1 | |
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2 | include "RTLabs/semantics.ma". |
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3 | include "common/StructuredTraces.ma". |
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4 | |
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5 | discriminator status_class. |
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6 | |
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7 | (* We augment states with a stack of function blocks (i.e. pointers) so that we |
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8 | can make sensible "program counters" for the abstract state definition, along |
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9 | with a proof that we will get the correct code when we do the lookup (which |
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10 | is done to find cost labels given a pc). |
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11 | |
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12 | Adding them to the semantics is an alternative, more direct approach. |
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13 | However, it makes animating the semantics extremely difficult, because it |
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14 | is hard to avoid normalising and displaying irrelevant parts of the global |
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15 | environment and proofs. |
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16 | |
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17 | We use blocks rather than identifiers because the global environments go |
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18 | |
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19 | identifier → block → definition |
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20 | |
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21 | and we'd have to introduce backwards lookups to find identifiers for |
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22 | function pointers. |
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23 | *) |
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24 | |
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25 | definition Ras_Fn_Match ≝ |
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26 | λge,state,fn_stack. |
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27 | match state with |
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28 | [ State f fs m ⇒ All2 … (λfr,b. find_funct_ptr ? ge b = Some ? (Internal ? (func fr))) (f::fs) fn_stack |
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29 | | Callstate fd _ _ fs _ ⇒ |
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30 | match fn_stack with |
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31 | [ nil ⇒ False |
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32 | | cons h t ⇒ find_funct_ptr ? ge h = Some ? fd ∧ |
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33 | All2 … (λfr,b. find_funct_ptr ? ge b = Some ? (Internal ? (func fr))) fs t |
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34 | ] |
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35 | | Returnstate _ _ fs _ ⇒ |
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36 | All2 … (λfr,b. find_funct_ptr ? ge b = Some ? (Internal ? (func fr))) fs fn_stack |
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37 | | Finalstate _ ⇒ fn_stack = [ ] |
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38 | ]. |
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39 | |
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40 | record RTLabs_state (ge:genv) : Type[0] ≝ { |
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41 | Ras_state :> state; |
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42 | Ras_fn_stack : list block; |
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43 | Ras_fn_match : Ras_Fn_Match ge Ras_state Ras_fn_stack |
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44 | }. |
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45 | |
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46 | (* Given a plain step of the RTLabs semantics, give the next state along with |
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47 | the shadow stack of function block numbers. Carefully defined so that the |
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48 | coercion back to the plain state always reduces. *) |
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49 | definition next_state : ∀ge. ∀s:RTLabs_state ge. ∀s':state. ∀t. |
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50 | eval_statement ge s = Value ??? 〈t,s'〉 → RTLabs_state ge ≝ |
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51 | λge,s,s',t,EX. mk_RTLabs_state ge s' |
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52 | (match s' return λs'. eval_statement ge s = Value ??? 〈t,s'〉 → ? with [ State _ _ _ ⇒ λ_. Ras_fn_stack … s | Callstate _ _ _ _ _ ⇒ λEX. func_block_of_exec … EX::Ras_fn_stack … s | Returnstate _ _ _ _ ⇒ λ_. tail … (Ras_fn_stack … s) | Finalstate _ ⇒ λ_. [ ] ] EX) |
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53 | ?. |
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54 | cases s' in EX ⊢ %; |
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55 | [ -s' #f #fs #m cases s -s #s #stk #mtc #EX whd in ⊢ (???%); inversion (eval_preserves … EX) |
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56 | [ #ge' #f1 #f2 #fs' #m1 #m2 #F #E1 #E2 #E3 #E4 destruct |
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57 | whd cases stk in mtc ⊢ %; [ * ] |
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58 | #hd #tl * #M1 #M2 % [ inversion F #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 destruct // |
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59 | | @M2 ] |
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60 | | #ge' #f1 #fs1 #m1 #fd #args #f' #dst #F #b #FFP #E1 #E2 #E3 #E4 destruct |
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61 | | #ge' #fn #locals #next #nok #sp #fs0 #m0 #args #dst #m' #E1 #E2 #E3 #E4 destruct |
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62 | whd cases stk in mtc ⊢ %; [ * ] |
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63 | #hd #tl #H @H |
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64 | | #H14 #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 destruct |
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65 | | #ge' #f0 #fs0 #rtv #dst #f' #m0 #F #E1 #E2 #E3 #E4 destruct |
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66 | cases stk in mtc ⊢ %; [ * ] #hd #tl * #M1 #M2 % |
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67 | [ inversion F #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 destruct // | @M2 ] |
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68 | | #ge' #r #dst #m0 #E1 #E2 #E3 #E4 destruct |
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69 | ] |
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70 | | -s' #fd #args #dst #fs #m #EX whd in ⊢ (???%); cases (func_block_of_exec … EX) #func_block #FFP |
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71 | whd % // -func_block cases s in EX ⊢ %; -s #s #stk #mtc #EX inversion (eval_preserves … EX) |
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72 | [ #ge' #f1 #f2 #fs' #m1 #m2 #F #E1 #E2 #E3 #E4 destruct |
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73 | | #ge' #f1 #fs1 #m1 #fd' #args' #f' #dst' #F #b #FFP #E1 #E2 #E3 #E4 destruct |
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74 | cases stk in mtc; [ * ] #b1 #bs * #M1 #M2 % |
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75 | [ inversion F #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 destruct // | @M2 ] |
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76 | | #ge' #fn #locals #next #nok #sp #fs0 #m0 #args #dst #m' #E1 #E2 #E3 #E4 destruct |
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77 | | #H14 #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 destruct |
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78 | | #ge' #f0 #fs0 #rtv #dst #f' #m0 #F #E1 #E2 #E3 #E4 destruct |
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79 | | #ge' #r #dst #m0 #E1 #E2 #E3 #E4 destruct |
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80 | ] |
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81 | | -s' #rtv #dst #fs #m #EX whd in ⊢ (???%); cases s in EX ⊢ %; -s #s #stk #mtc #EX inversion (eval_preserves … EX) |
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82 | [ #ge' #f1 #f2 #fs' #m1 #m2 #F #E1 #E2 #E3 #E4 destruct |
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83 | | #ge' #f1 #fs1 #m1 #fd' #args' #f' #dst' #F #b #FFP #E1 #E2 #E3 #E4 destruct |
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84 | | #ge' #fn #locals #next #nok #sp #fs0 #m0 #args #dst #m' #E1 #E2 #E3 #E4 destruct |
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85 | | #ge' #f #fs' #m' #rtv' #dst' #m' #E1 #E2 #E3 #E4 destruct |
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86 | cases stk in mtc ⊢ %; [ * ] #b #bs * #_ #H @H |
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87 | | #ge' #f0 #fs0 #rtv #dst #f' #m0 #F #E1 #E2 #E3 #E4 destruct |
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88 | | #ge' #r #dst #m0 #E1 #E2 #E3 #E4 destruct |
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89 | ] |
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90 | | #r #EX whd @refl |
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91 | ] qed. |
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92 | |
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93 | (* |
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94 | definition next_state : ∀ge. ∀s:RTLabs_state ge. ∀s':state. ∀t. |
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95 | eval_statement ge s = Value ??? 〈t,s'〉 → RTLabs_state ge ≝ |
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96 | λge,s,s',t. |
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97 | match s' return λs'. eval_statement ge s = Value ??? 〈t,s'〉 → RTLabs_state ge with |
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98 | [ State f fs m ⇒ λEX. mk_RTLabs_state ge (State f fs m) (Ras_fn_stack … s) ? |
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99 | | Callstate fd args dst fs m ⇒ λEX. mk_RTLabs_state ge (Callstate fd args dst fs m) (func_block_of_exec … EX::Ras_fn_stack … s) ? |
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100 | | Returnstate rtv dst fs m ⇒ λEX. mk_RTLabs_state ge (Returnstate rtv dst fs m) (tail … (Ras_fn_stack … s)) ? |
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101 | | Finalstate r ⇒ λEX. mk_RTLabs_state ge (Finalstate r) [ ] ? |
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102 | ]. |
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103 | [ cases s in EX ⊢ %; -s #s #stk #mtc #EX inversion (eval_preserves … EX) |
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104 | [ #ge' #f1 #f2 #fs' #m1 #m2 #F #E1 #E2 #E3 #E4 destruct |
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105 | whd cases stk in mtc ⊢ %; [ * ] |
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106 | #hd #tl * #M1 #M2 % [ inversion F #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 destruct // |
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107 | | @M2 ] |
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108 | | #ge' #f1 #fs1 #m1 #fd #args #f' #dst #F #b #FFP #E1 #E2 #E3 #E4 destruct |
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109 | | #ge' #fn #locals #next #nok #sp #fs0 #m0 #args #dst #m' #E1 #E2 #E3 #E4 destruct |
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110 | whd cases stk in mtc ⊢ %; [ * ] |
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111 | #hd #tl #H @H |
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112 | | #H14 #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 destruct |
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113 | | #ge' #f0 #fs0 #rtv #dst #f' #m0 #F #E1 #E2 #E3 #E4 destruct |
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114 | cases stk in mtc ⊢ %; [ * ] #hd #tl * #M1 #M2 % |
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115 | [ inversion F #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 destruct // | @M2 ] |
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116 | | #ge' #r #dst #m0 #E1 #E2 #E3 #E4 destruct |
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117 | ] |
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118 | | cases (func_block_of_exec … EX) #func_block #FFP |
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119 | whd % // -func_block cases s in EX ⊢ %; -s #s #stk #mtc #EX inversion (eval_preserves … EX) |
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120 | [ #ge' #f1 #f2 #fs' #m1 #m2 #F #E1 #E2 #E3 #E4 destruct |
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121 | | #ge' #f1 #fs1 #m1 #fd' #args' #f' #dst' #F #b #FFP #E1 #E2 #E3 #E4 destruct |
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122 | cases stk in mtc; [ * ] #b1 #bs * #M1 #M2 % |
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123 | [ inversion F #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 destruct // | @M2 ] |
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124 | | #ge' #fn #locals #next #nok #sp #fs0 #m0 #args #dst #m' #E1 #E2 #E3 #E4 destruct |
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125 | | #H14 #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 destruct |
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126 | | #ge' #f0 #fs0 #rtv #dst #f' #m0 #F #E1 #E2 #E3 #E4 destruct |
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127 | | #ge' #r #dst #m0 #E1 #E2 #E3 #E4 destruct |
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128 | ] |
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129 | | cases s in EX ⊢ %; -s #s #stk #mtc #EX inversion (eval_preserves … EX) |
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130 | [ #ge' #f1 #f2 #fs' #m1 #m2 #F #E1 #E2 #E3 #E4 destruct |
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131 | | #ge' #f1 #fs1 #m1 #fd' #args' #f' #dst' #F #b #FFP #E1 #E2 #E3 #E4 destruct |
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132 | | #ge' #fn #locals #next #nok #sp #fs0 #m0 #args #dst #m' #E1 #E2 #E3 #E4 destruct |
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133 | | #ge' #f #fs' #m' #rtv' #dst' #m' #E1 #E2 #E3 #E4 destruct |
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134 | cases stk in mtc ⊢ %; [ * ] #b #bs * #_ #H @H |
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135 | | #ge' #f0 #fs0 #rtv #dst #f' #m0 #F #E1 #E2 #E3 #E4 destruct |
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136 | | #ge' #r #dst #m0 #E1 #E2 #E3 #E4 destruct |
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137 | ] |
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138 | | whd @refl |
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139 | ] qed.*) |
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140 | |
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141 | (* NB: For RTLabs we only classify branching behaviour as jumps. Other jumps |
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142 | will be added later (LTL → LIN). *) |
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143 | |
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144 | definition RTLabs_classify : state → status_class ≝ |
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145 | λs. match s with |
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146 | [ State f _ _ ⇒ |
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147 | match lookup_present ?? (f_graph (func f)) (next f) (next_ok f) with |
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148 | [ St_cond _ _ _ ⇒ cl_jump |
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149 | | St_jumptable _ _ ⇒ cl_jump |
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150 | | _ ⇒ cl_other |
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151 | ] |
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152 | | Callstate _ _ _ _ _ ⇒ cl_call |
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153 | | Returnstate _ _ _ _ ⇒ cl_return |
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154 | | Finalstate _ ⇒ cl_other |
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155 | ]. |
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156 | |
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157 | (* We define a straight "is this a cost label" pair of functions, which is |
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158 | convenient for most of our uses here (because we can make a hypothesis of |
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159 | it without naming the label), and a pair which return the label to fit the |
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160 | definition of abstract_status. *) |
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161 | |
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162 | definition is_cost_label : statement → bool ≝ |
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163 | λs. match s with [ St_cost _ _ ⇒ true | _ ⇒ false ]. |
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164 | |
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165 | definition RTLabs_cost : state → bool ≝ |
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166 | λs. match s with |
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167 | [ State f fs m ⇒ |
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168 | is_cost_label (lookup_present ?? (f_graph (func f)) (next f) (next_ok f)) |
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169 | | _ ⇒ false |
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170 | ]. |
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171 | |
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172 | definition cost_label_of : statement → option costlabel ≝ |
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173 | λs. match s with [ St_cost s _ ⇒ Some ? s | _ ⇒ None ? ]. |
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174 | |
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175 | definition RTLabs_cost_label : state → option costlabel ≝ |
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176 | λs. match s with |
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177 | [ State f fs m ⇒ |
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178 | cost_label_of (lookup_present ?? (f_graph (func f)) (next f) (next_ok f)) |
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179 | | _ ⇒ None ? |
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180 | ]. |
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181 | |
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182 | inductive RTLabs_pc : Type[0] ≝ |
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183 | | rapc_state : block → label → RTLabs_pc |
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184 | | rapc_call : block → RTLabs_pc |
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185 | | rapc_ret : option block → RTLabs_pc |
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186 | | rapc_fin : RTLabs_pc |
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187 | . |
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188 | |
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189 | definition block_eq : DeqSet ≝ mk_DeqSet block eq_block ?. |
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190 | #x #y @eq_block_elim |
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191 | [ #E destruct /2/ |
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192 | | * #NE % #E destruct cases (NE (refl ??)) |
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193 | ] qed. |
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194 | |
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195 | definition RTLabs_pc_eq : RTLabs_pc → RTLabs_pc → bool ≝ |
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196 | λx,y. match x with |
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197 | [ rapc_state b1 l1 ⇒ match y with [ rapc_state b2 l2 ⇒ eq_block b1 b2 ∧ eq_identifier … l1 l2 | _ ⇒ false ] |
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198 | | rapc_call b1 ⇒ match y with [ rapc_call b2 ⇒ eq_block b1 b2 | _ ⇒ false ] |
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199 | | rapc_ret b1 ⇒ match y with [ rapc_ret b2 ⇒ eq_option block_eq b1 b2 | _ ⇒ false ] |
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200 | | rapc_fin ⇒ match y with [ rapc_fin ⇒ true | _ ⇒ false ] |
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201 | ]. |
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202 | |
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203 | definition RTLabs_deqset : DeqSet ≝ mk_DeqSet RTLabs_pc RTLabs_pc_eq ?. |
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204 | whd in match RTLabs_pc_eq; whd in match eq_option; whd in match block_eq; |
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205 | * [ #b1 #l1 | #b1 | * [2: #b1 ] | ] |
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206 | * [ 1,5,9,13,17: #b2 #l2 | 2,6,10,14,18: #b2 | 3,7,11,15,19: * [2,4,6,8,10: #b2] | *: ] |
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207 | normalize nodelta |
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208 | [ 1,7,13: @eq_block_elim [ 1,3,5: #E destruct | *: * #NE ] ] |
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209 | [ 1,4: @eq_identifier_elim [ 1,3: #E destruct | *: * #NE ] ] |
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210 | normalize % #E destruct try (cases (NE (refl ??))) @refl |
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211 | qed. |
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212 | |
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213 | definition RTLabs_state_to_pc : ∀ge. RTLabs_state ge → RTLabs_deqset ≝ |
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214 | λge,s. match s with [ mk_RTLabs_state s' stk mtc0 ⇒ |
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215 | match s' return λs'. Ras_Fn_Match ? s' ? → ? with |
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216 | [ State f fs m ⇒ match stk return λstk. Ras_Fn_Match ?? stk → ? with [ nil ⇒ λmtc. ⊥ | cons b _ ⇒ λ_. rapc_state b (next … f) ] |
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217 | | Callstate _ _ _ _ _ ⇒ match stk return λstk. Ras_Fn_Match ?? stk → ? with [ nil ⇒ λmtc. ⊥ | cons b _ ⇒ λ_. rapc_call b ] |
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218 | | Returnstate _ _ _ _ ⇒ match stk with [ nil ⇒ λ_. rapc_ret (None ?) | cons b _ ⇒ λ_. rapc_ret (Some ? b) ] |
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219 | | Finalstate _ ⇒ λmtc. rapc_fin |
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220 | ] mtc0 ]. |
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221 | whd in mtc; cases mtc |
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222 | qed. |
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223 | |
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224 | definition RTLabs_pc_to_cost_label : ∀ge. RTLabs_pc → option costlabel ≝ |
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225 | λge,pc. |
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226 | match pc with |
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227 | [ rapc_state b l ⇒ |
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228 | match find_funct_ptr … ge b with [ None ⇒ None ? | Some fd ⇒ |
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229 | match fd with [ Internal f ⇒ match lookup ?? (f_graph f) l with [ Some s ⇒ cost_label_of s | _ ⇒ None ? ] | _ ⇒ None ? ] ] |
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230 | | _ ⇒ None ? |
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231 | ]. |
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232 | |
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233 | definition RTLabs_status : genv → abstract_status ≝ |
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234 | λge. |
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235 | mk_abstract_status |
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236 | (RTLabs_state ge) |
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237 | (λs,s'. ∃t,EX. next_state ge s s' t EX = s') |
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238 | RTLabs_deqset |
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239 | (RTLabs_state_to_pc ge) |
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240 | (λs,c. RTLabs_classify s = c) |
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241 | (RTLabs_pc_to_cost_label ge) |
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242 | (λs,s'. match s with |
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243 | [ mk_Sig s p ⇒ |
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244 | match s return λs. RTLabs_classify s = cl_call → ? with |
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245 | [ Callstate fd args dst stk m ⇒ |
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246 | λ_. match s' with |
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247 | [ State f fs m ⇒ match stk with [ nil ⇒ False | cons h t ⇒ next h = next f ∧ f_graph (func h) = f_graph (func f) ] |
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248 | | Finalstate r ⇒ stk = [ ] |
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249 | | _ ⇒ False |
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250 | ] |
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251 | | State f fs m ⇒ λH.⊥ |
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252 | | _ ⇒ λH.⊥ |
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253 | ] p |
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254 | ]) |
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255 | (λs. RTLabs_is_final s ≠ None ?). |
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256 | [ normalize in H; destruct |
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257 | | normalize in H; destruct |
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258 | | whd in H:(??%?); |
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259 | cases (lookup_present LabelTag statement (f_graph (func f)) (next f) (next_ok f)) in H; |
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260 | normalize try #a try #b try #c try #d try #e try #g try #h try #i try #j destruct |
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261 | ] qed. |
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262 | |
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263 | (* Allow us to move between the different notions of when a state is cost |
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264 | labelled. *) |
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265 | |
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266 | lemma RTLabs_costed : ∀ge. ∀s:RTLabs_state ge. |
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267 | RTLabs_cost s = true ↔ |
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268 | as_costed (RTLabs_status ge) s. |
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269 | cut (None (identifier CostTag) ≠ None ? → False) [ * /2/ ] #NONE |
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270 | #ge * * |
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271 | [ * #func #locals #next #nok #sp #r #fs #m #stk #mtc |
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272 | whd in ⊢ (??%); whd in ⊢ (??(?(??%?))); |
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273 | whd in match (as_pc_of ??); |
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274 | cases stk in mtc ⊢ %; [ * ] #func_block #stk' * #M1 #M2 |
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275 | whd in ⊢ (??(?(??%?))); >M1 whd in ⊢ (??(?(??%?))); |
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276 | >(lookup_lookup_present … nok) |
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277 | whd in ⊢ (?(??%?)(?(??%?))); |
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278 | % cases (lookup_present ?? (f_graph func) ??) normalize |
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279 | #A try #B try #C try #D try #E try #F try #G try #H try #G destruct |
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280 | try (% #E' destruct) |
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281 | cases (NONE ?) assumption |
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282 | | #fd #args #dst #fs #m #stk #mtc % |
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283 | [ #E normalize in E; destruct |
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284 | | whd in ⊢ (% → ?); whd in ⊢ (?(??%?) → ?); whd in match (as_pc_of ??); |
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285 | cases stk in mtc ⊢ %; [*] #fblk #fblks #mtc whd in ⊢ (?(??%?) → ?); |
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286 | #H cases (NONE H) |
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287 | ] |
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288 | | #v #dst #fs #m #stk #mtc % |
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289 | [ #E normalize in E; destruct |
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290 | | whd in ⊢ (% → ?); whd in ⊢ (?(??%?) → ?); whd in match (as_pc_of ??); |
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291 | cases stk in mtc ⊢ %; [2: #fblk #fblks ] #mtc whd in ⊢ (?(??%?) → ?); |
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292 | #H cases (NONE H) |
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293 | ] |
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294 | | #r #stk #mtc % |
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295 | [ #E normalize in E; destruct |
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296 | | #E normalize in E; cases (NONE E) |
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297 | ] |
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298 | ] qed. |
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299 | |
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300 | lemma RTLabs_not_cost : ∀ge. ∀s:RTLabs_state ge. |
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301 | RTLabs_cost s = false → |
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302 | ¬ as_costed (RTLabs_status ge) s. |
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303 | #ge #s #E % #C >(proj2 … (RTLabs_costed ??)) in E; // #E destruct |
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304 | qed. |
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305 | |
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306 | (* Before attempting to construct a structured trace, let's show that we can |
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307 | form flat traces with evidence that they were constructed from an execution. |
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308 | |
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309 | For now we don't consider I/O. *) |
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310 | |
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311 | |
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312 | coinductive exec_no_io (o:Type[0]) (i:o → Type[0]) : execution state o i → Prop ≝ |
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313 | | noio_stop : ∀a,b,c. exec_no_io o i (e_stop … a b c) |
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314 | | noio_step : ∀a,b,e. exec_no_io o i e → exec_no_io o i (e_step … a b e) |
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315 | | noio_wrong : ∀m. exec_no_io o i (e_wrong … m). |
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316 | |
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317 | (* add I/O? *) |
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318 | coinductive flat_trace (o:Type[0]) (i:o → Type[0]) (ge:genv) : state → Type[0] ≝ |
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319 | | ft_stop : ∀s. RTLabs_is_final s ≠ None ? → flat_trace o i ge s |
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320 | | ft_step : ∀s,tr,s'. eval_statement ge s = Value ??? 〈tr,s'〉 → flat_trace o i ge s' → flat_trace o i ge s |
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321 | | ft_wrong : ∀s,m. RTLabs_is_final s = None ? → eval_statement ge s = Wrong ??? m → flat_trace o i ge s. |
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322 | |
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323 | coinductive not_wrong (o:Type[0]) (i:o → Type[0]) (ge:genv) : ∀s. flat_trace o i ge s → Type[0] ≝ |
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324 | | nw_stop : ∀s,H. not_wrong o i ge s (ft_stop o i ge s H) |
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325 | | nw_step : ∀s,tr,s',H,tr'. not_wrong o i ge s' tr' → not_wrong o i ge s (ft_step o i ge s tr s' H tr'). |
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326 | |
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327 | lemma still_not_wrong : ∀o,i,ge,s,tr,s',H,tr'. |
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328 | not_wrong o i ge s (ft_step o i ge s tr s' H tr') → |
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329 | not_wrong o i ge s' tr'. |
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330 | #o #i #ge #s #tr #s' #H #tr' #NW inversion NW |
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331 | [ #H105 #H106 #H107 #H108 #H109 destruct |
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332 | | #H111 #H112 #H113 #H114 #H115 #H116 #H117 #H118 #H119 destruct // |
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333 | ] qed. |
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334 | |
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335 | let corec make_flat_trace ge s |
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336 | (NF:RTLabs_is_final s = None ?) |
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337 | (H:exec_no_io … (exec_inf_aux … RTLabs_fullexec ge (eval_statement ge s))) : |
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338 | flat_trace io_out io_in ge s ≝ |
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339 | let e ≝ exec_inf_aux … RTLabs_fullexec ge (eval_statement ge s) in |
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340 | match e return λx. e = x → ? with |
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341 | [ e_stop tr i s' ⇒ λE. ft_step … s tr s' ? (ft_stop … s' ?) |
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342 | | e_step tr s' e' ⇒ λE. ft_step … s tr s' ? (make_flat_trace ge s' ??) |
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343 | | e_wrong m ⇒ λE. ft_wrong … s m ?? |
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344 | | e_interact o f ⇒ λE. ⊥ |
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345 | ] (refl ? e). |
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346 | [ 1,2: whd in E:(??%?); >exec_inf_aux_unfold in E; |
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347 | cases (eval_statement ge s) |
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348 | [ 1,4: #O #K whd in ⊢ (??%? → ?); #E destruct |
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349 | | 2,5: * #tr #s1 whd in ⊢ (??%? → ?); |
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350 | >(?:is_final ????? = RTLabs_is_final s1) // |
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351 | lapply (refl ? (RTLabs_is_final s1)) |
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352 | cases (RTLabs_is_final s1) in ⊢ (???% → %); |
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353 | [ 1,3: #_ whd in ⊢ (??%? → ?); #E destruct |
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354 | | #i #_ whd in ⊢ (??%? → ?); #E destruct /2/ @refl |
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355 | | #i #E whd in ⊢ (??%? → ?); #E2 destruct >E % #E' destruct |
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356 | ] |
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357 | | *: #m whd in ⊢ (??%? → ?); #E destruct |
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358 | ] |
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359 | | whd in E:(??%?); >exec_inf_aux_unfold in E; |
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360 | cases (eval_statement ge s) |
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361 | [ #O #K whd in ⊢ (??%? → ?); #E destruct |
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362 | | * #tr #s1 whd in ⊢ (??%? → ?); |
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363 | cases (is_final ?????) |
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364 | [ whd in ⊢ (??%? → ?); #E destruct @refl |
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365 | | #i whd in ⊢ (??%? → ?); #E destruct |
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366 | ] |
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367 | | #m whd in ⊢ (??%? → ?); #E destruct |
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368 | ] |
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369 | | whd in E:(??%?); >E in H; #H >exec_inf_aux_unfold in E; |
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370 | cases (eval_statement ge s) |
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371 | [ #O #K whd in ⊢ (??%? → ?); #E destruct |
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372 | | * #tr #s1 whd in ⊢ (??%? → ?); |
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373 | cases (is_final ?????) |
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374 | [ whd in ⊢ (??%? → ?); #E |
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375 | change with (eval_statement ge s1) in E:(??(??????(?????%))?); |
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376 | destruct |
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377 | inversion H |
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378 | [ #a #b #c #E1 destruct |
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379 | | #trx #sx #ex #H1 #E2 #E3 destruct @H1 |
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380 | | #m #E1 destruct |
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381 | ] |
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382 | | #i whd in ⊢ (??%? → ?); #E destruct |
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383 | ] |
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384 | | #m whd in ⊢ (??%? → ?); #E destruct |
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385 | ] |
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386 | | whd in E:(??%?); >exec_inf_aux_unfold in E; |
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387 | cases (eval_statement ge s) |
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388 | [ #o #K whd in ⊢ (??%? → ?); #E destruct |
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389 | | * #tr #s1 whd in ⊢ (??%? → ?); |
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390 | lapply (refl ? (RTLabs_is_final s1)) |
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391 | change with (RTLabs_is_final s1) in ⊢ (? → ??(match % with [_⇒?|_⇒?])? → ?); |
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392 | cases (RTLabs_is_final s1) in ⊢ (???% → %); |
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393 | [ #F #E whd in E:(??%?); destruct @F |
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394 | | #r #F #E whd in E:(??%?); destruct |
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395 | ] |
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396 | | #m #E whd in E:(??%?); destruct |
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397 | ] |
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398 | | @NF |
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399 | | whd in E:(??%?); >exec_inf_aux_unfold in E; |
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400 | cases (eval_statement ge s) |
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401 | [ #O #K whd in ⊢ (??%? → ?); #E destruct |
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402 | | * #tr1 #s1 whd in ⊢ (??%? → ?); |
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403 | cases (is_final ?????) |
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404 | [ whd in ⊢ (??%? → ?); #E destruct |
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405 | | #i whd in ⊢ (??%? → ?); #E destruct |
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406 | ] |
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407 | | #m whd in ⊢ (??%? → ?); #E destruct @refl |
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408 | ] |
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409 | | whd in E:(??%?); >E in H; #H |
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410 | inversion H |
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411 | [ #a #b #c #E destruct |
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412 | | #a #b #c #d #E1 destruct |
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413 | | #m #E1 destruct |
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414 | ] |
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415 | ] qed. |
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416 | |
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417 | let corec make_whole_flat_trace p s |
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418 | (H:exec_no_io … (exec_inf … RTLabs_fullexec p)) |
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419 | (I:make_initial_state ??? p = OK ? s) : |
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420 | flat_trace io_out io_in (make_global … RTLabs_fullexec p) s ≝ |
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421 | let ge ≝ make_global … p in |
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422 | let e ≝ exec_inf_aux ?? RTLabs_fullexec ge (Value … 〈E0, s〉) in |
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423 | match e return λx. e = x → ? with |
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424 | [ e_stop tr i s' ⇒ λE. ft_stop ?? ge s ? |
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425 | | e_step _ _ e' ⇒ λE. make_flat_trace ge s ?? |
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426 | | e_wrong m ⇒ λE. ⊥ |
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427 | | e_interact o f ⇒ λE. ⊥ |
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428 | ] (refl ? e). |
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429 | [ whd in E:(??%?); >exec_inf_aux_unfold in E; |
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430 | whd in ⊢ (??%? → ?); |
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431 | change with (RTLabs_is_final s) in ⊢ (??(match % with[_⇒?|_⇒?])? → ?); |
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432 | cases (RTLabs_is_final s) |
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433 | [ #E whd in E:(??%?); destruct |
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434 | | #r #E % #E' destruct |
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435 | ] |
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436 | | @(initial_state_is_not_final … I) |
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437 | | whd in H:(???%); >I in H; whd in ⊢ (???% → ?); whd in E:(??%?); |
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438 | >exec_inf_aux_unfold in E ⊢ %; whd in ⊢ (??%? → ???% → ?); cases (is_final ?????) |
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439 | [ whd in ⊢ (??%? → ???% → ?); #E #H inversion H |
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440 | [ #a #b #c #E1 destruct |
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441 | | #tr1 #s1 #e1 #H1 #E1 #E2 -E2 -I destruct (E1) |
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442 | @H1 |
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443 | | #m #E1 destruct |
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444 | ] |
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445 | | #i whd in ⊢ (??%? → ???% → ?); #E destruct |
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446 | ] |
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447 | | whd in E:(??%?); >exec_inf_aux_unfold in E; whd in ⊢ (??%? → ?); |
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448 | cases (is_final ?????) [2:#i] whd in ⊢ (??%? → ?); #E destruct |
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449 | | whd in E:(??%?); >exec_inf_aux_unfold in E; whd in ⊢ (??%? → ?); |
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450 | cases (is_final ?????) [2:#i] whd in ⊢ (??%? → ?); #E destruct |
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451 | ] qed. |
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452 | |
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453 | (* Need a way to choose whether a called function terminates. Then, |
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454 | if the initial function terminates we generate a purely inductive structured trace, |
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455 | otherwise we start generating the coinductive one, and on every function call |
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456 | use the choice method again to decide whether to step over or keep going. |
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457 | |
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458 | Not quite what we need - have to decide on seeing each label whether we will see |
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459 | another or hit a non-terminating call? |
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460 | |
---|
461 | Also - need the notion of well-labelled in order to break loops. |
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462 | |
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463 | |
---|
464 | |
---|
465 | outline: |
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466 | |
---|
467 | does function terminate? |
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468 | - yes, get (bound on the number of steps until return), generate finite |
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469 | structure using bound as termination witness |
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470 | - no, get (¬ bound on steps to return), start building infinite trace out of |
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471 | finite steps. At calls, check for termination, generate appr. form. |
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472 | |
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473 | generating the finite parts: |
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474 | |
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475 | We start with the status after the call has been executed; well-labelling tells |
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476 | us that this is a labelled state. Now we want to generate a trace_label_return |
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477 | and also return the remainder of the flat trace. |
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478 | |
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479 | *) |
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480 | |
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481 | (* [will_return ge depth s trace] says that after a finite number of steps of |
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482 | [trace] from [s] we reach the return state for the current function. [depth] |
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483 | performs the call/return counting necessary for handling deeper function |
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484 | calls. It should be zero at the top level. *) |
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485 | inductive will_return (ge:genv) : nat → ∀s. flat_trace io_out io_in ge s → Type[0] ≝ |
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486 | | wr_step : ∀s,tr,s',depth,EX,trace. |
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487 | RTLabs_classify s = cl_other ∨ RTLabs_classify s = cl_jump → |
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488 | will_return ge depth s' trace → |
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489 | will_return ge depth s (ft_step ?? ge s tr s' EX trace) |
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490 | | wr_call : ∀s,tr,s',depth,EX,trace. |
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491 | RTLabs_classify s = cl_call → |
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492 | will_return ge (S depth) s' trace → |
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493 | will_return ge depth s (ft_step ?? ge s tr s' EX trace) |
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494 | | wr_ret : ∀s,tr,s',depth,EX,trace. |
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495 | RTLabs_classify s = cl_return → |
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496 | will_return ge depth s' trace → |
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497 | will_return ge (S depth) s (ft_step ?? ge s tr s' EX trace) |
---|
498 | (* Note that we require the ability to make a step after the return (this |
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499 | corresponds to somewhere that will be guaranteed to be a label at the |
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500 | end of the compilation chain). *) |
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501 | | wr_base : ∀s,tr,s',EX,trace. |
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502 | RTLabs_classify s = cl_return → |
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503 | will_return ge O s (ft_step ?? ge s tr s' EX trace) |
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504 | . |
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505 | |
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506 | (* The way we will use [will_return] won't satisfy Matita's guardedness check, |
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507 | so we will measure the length of these termination proofs and use an upper |
---|
508 | bound to show termination of the finite structured trace construction |
---|
509 | functions. *) |
---|
510 | |
---|
511 | let rec will_return_length ge d s tr (T:will_return ge d s tr) on T : nat ≝ |
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512 | match T with |
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513 | [ wr_step _ _ _ _ _ _ _ T' ⇒ S (will_return_length … T') |
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514 | | wr_call _ _ _ _ _ _ _ T' ⇒ S (will_return_length … T') |
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515 | | wr_ret _ _ _ _ _ _ _ T' ⇒ S (will_return_length … T') |
---|
516 | | wr_base _ _ _ _ _ _ ⇒ S O |
---|
517 | ]. |
---|
518 | |
---|
519 | include alias "arithmetics/nat.ma". |
---|
520 | |
---|
521 | (* Specialised to the particular situation it is used in. *) |
---|
522 | lemma wrl_nonzero : ∀ge,d,s,tr,T. O ≥ 3 * (will_return_length ge d s tr T) → False. |
---|
523 | #ge #d #s #tr * #s1 #tr1 #s2 [ 1,2,3: #d ] #EX #tr' #CL [1,2,3:#IH] |
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524 | whd in ⊢ (??(??%) → ?); |
---|
525 | >commutative_times |
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526 | #H lapply (le_plus_b … H) |
---|
527 | #H lapply (le_to_leb_true … H) |
---|
528 | normalize #E destruct |
---|
529 | qed. |
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530 | |
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531 | let rec will_return_end ge d s tr (T:will_return ge d s tr) on T : 𝚺s'.flat_trace io_out io_in ge s' ≝ |
---|
532 | match T with |
---|
533 | [ wr_step _ _ _ _ _ _ _ T' ⇒ will_return_end … T' |
---|
534 | | wr_call _ _ _ _ _ _ _ T' ⇒ will_return_end … T' |
---|
535 | | wr_ret _ _ _ _ _ _ _ T' ⇒ will_return_end … T' |
---|
536 | | wr_base _ _ _ _ tr' _ ⇒ mk_DPair ? (λs.flat_trace io_out io_in ge s) ? tr' |
---|
537 | ]. |
---|
538 | |
---|
539 | (* Inversion lemmas on [will_return] that also note the effect on the length |
---|
540 | of the proof. *) |
---|
541 | lemma will_return_call : ∀ge,d,s,tr,s',EX,trace. |
---|
542 | RTLabs_classify s = cl_call → |
---|
543 | ∀TM:will_return ge d s (ft_step ?? ge s tr s' EX trace). |
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544 | ΣTM':will_return ge (S d) s' trace. will_return_length … TM > will_return_length … TM' ∧ will_return_end … TM = will_return_end … TM'. |
---|
545 | #ge #d #s #tr #s' #EX #trace #CL #TERM inversion TERM |
---|
546 | [ #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 #H28 #H29 #H30 #H31 @⊥ destruct >CL in H25; * #E destruct |
---|
547 | | #H33 #H34 #H35 #H36 #H37 #H38 #H39 #H40 #H41 #H42 #H43 #H44 #H45 destruct % /2/ |
---|
548 | | #H47 #H48 #H49 #H50 #H51 #H52 #H53 #H54 #H55 #H56 #H57 #H58 #H59 @⊥ destruct >CL in H53; #E destruct |
---|
549 | | #H61 #H62 #H63 #H64 #H65 #H66 #H67 #H68 #H69 #H70 @⊥ destruct >CL in H66; #E destruct |
---|
550 | ] qed. |
---|
551 | |
---|
552 | lemma will_return_return : ∀ge,d,s,tr,s',EX,trace. |
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553 | RTLabs_classify s = cl_return → |
---|
554 | ∀TM:will_return ge d s (ft_step ?? ge s tr s' EX trace). |
---|
555 | match d with |
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556 | [ O ⇒ will_return_end … TM = ❬s', trace❭ |
---|
557 | | S d' ⇒ |
---|
558 | ΣTM':will_return ge d' s' trace. will_return_length … TM > will_return_length … TM' ∧ will_return_end … TM = will_return_end … TM' |
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559 | ]. |
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560 | #ge #d #s #tr #s' #EX #trace #CL #TERM inversion TERM |
---|
561 | [ #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 #H28 #H29 #H30 #H31 @⊥ destruct >CL in H25; * #E destruct |
---|
562 | | #H33 #H34 #H35 #H36 #H37 #H38 #H39 #H40 #H41 #H42 #H43 #H44 #H45 @⊥ destruct >CL in H39; #E destruct |
---|
563 | | #H47 #H48 #H49 #H50 #H51 #H52 #H53 #H54 #H55 #H56 #H57 #H58 #H59 destruct % /2/ |
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564 | | #H61 #H62 #H63 #H64 #H65 #H66 #H67 #H68 #H69 #H70 destruct @refl |
---|
565 | ] qed. |
---|
566 | |
---|
567 | lemma will_return_notfn : ∀ge,d,s,tr,s',EX,trace. |
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568 | (RTLabs_classify s = cl_other) ⊎ (RTLabs_classify s = cl_jump) → |
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569 | ∀TM:will_return ge d s (ft_step ?? ge s tr s' EX trace). |
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570 | ΣTM':will_return ge d s' trace. will_return_length … TM > will_return_length … TM' ∧ will_return_end … TM = will_return_end … TM'. |
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571 | #ge #d #s #tr #s' #EX #trace * #CL #TERM inversion TERM |
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572 | [ #H290 #H291 #H292 #H293 #H294 #H295 #H296 #H297 #H298 #H299 #H300 #H301 #H302 destruct % /2/ |
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573 | | #H304 #H305 #H306 #H307 #H308 #H309 #H310 #H311 #H312 #H313 #H314 #H315 #H316 @⊥ destruct >CL in H310; #E destruct |
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574 | | #H318 #H319 #H320 #H321 #H322 #H323 #H324 #H325 #H326 #H327 #H328 #H329 #H330 @⊥ destruct >CL in H324; #E destruct |
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575 | | #H332 #H333 #H334 #H335 #H336 #H337 #H338 #H339 #H340 #H341 @⊥ destruct >CL in H337; #E destruct |
---|
576 | | #H343 #H344 #H345 #H346 #H347 #H348 #H349 #H350 #H351 #H352 #H353 #H354 #H355 destruct % /2/ |
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577 | | #H357 #H358 #H359 #H360 #H361 #H362 #H363 #H364 #H365 #H366 #H367 #H368 #H369 @⊥ destruct >CL in H363; #E destruct |
---|
578 | | #H371 #H372 #H373 #H374 #H375 #H376 #H377 #H378 #H379 #H380 #H381 #H382 #H383 @⊥ destruct >CL in H377; #E destruct |
---|
579 | | #H385 #H386 #H387 #H388 #H389 #H390 #H391 #H392 #H393 #H394 @⊥ destruct >CL in H390; #E destruct |
---|
580 | ] qed. |
---|
581 | |
---|
582 | (* When it comes to building bits of nonterminating executions we'll need to be |
---|
583 | able to glue termination proofs together. *) |
---|
584 | |
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585 | lemma will_return_prepend : ∀ge,d1,s1,t1. |
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586 | ∀T1:will_return ge d1 s1 t1. |
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587 | ∀d2,s2,t2. |
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588 | will_return ge d2 s2 t2 → |
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589 | will_return_end … T1 = ❬s2, t2❭ → |
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590 | will_return ge (d1 + S d2) s1 t1. |
---|
591 | #ge #d1 #s1 #tr1 #T1 elim T1 |
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592 | [ #s #tr #s' #depth #EX #t #CL #T #IH #d2 #s2 #t2 #T2 #E |
---|
593 | %1 // @(IH … T2) @E |
---|
594 | | #s #tr #s' #depth #EX #t #CL #T #IH #d2 #s2 #t2 #T2 #E %2 // @(IH … T2) @E |
---|
595 | | #s #tr #s' #depth #EX #t #CL #T #IH #s2 #s2 #t2 #T2 #E %3 // @(IH … T2) @E |
---|
596 | | #s #tr #s' #EX #t #CL #d2 #s2 #t2 #T2 #E normalize in E; destruct %3 // |
---|
597 | ] qed. |
---|
598 | |
---|
599 | discriminator nat. |
---|
600 | |
---|
601 | lemma will_return_remove_call : ∀ge,d1,s1,t1. |
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602 | ∀T1:will_return ge d1 s1 t1. |
---|
603 | ∀d2. |
---|
604 | will_return ge (d1 + S d2) s1 t1 → |
---|
605 | ∀s2,t2. |
---|
606 | will_return_end … T1 = ❬s2, t2❭ → |
---|
607 | will_return ge d2 s2 t2. |
---|
608 | (* The key part of the proof is to show that the two termination proofs follow |
---|
609 | the same pattern. *) |
---|
610 | #ge #d1x #s1x #t1x #T1 elim T1 |
---|
611 | [ #s #tr #s' #d1 #EX #t #CL #T #IH #d2 #T2 #s2 #t2 #E @IH |
---|
612 | [ inversion T2 [ #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 #H13 destruct // |
---|
613 | | #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 @⊥ destruct |
---|
614 | >H21 in CL; * #E destruct |
---|
615 | | #H29 #H30 #H31 #H32 #H33 #H34 #H35 #H36 #H37 #H38 #H39 #H40 #H41 @⊥ destruct |
---|
616 | >H35 in CL; * #E destruct |
---|
617 | | #H43 #H44 #H45 #H46 #H47 #H48 #H49 #H50 #H51 #H52 @⊥ destruct |
---|
618 | >H48 in CL; * #E destruct |
---|
619 | ] |
---|
620 | | @E |
---|
621 | ] |
---|
622 | | #s #tr #s' #d1 #EX #t #CL #T #IH #d2 #T2 #s2 #t2 #E @IH |
---|
623 | [ inversion T2 [ #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 #H13 @⊥ destruct |
---|
624 | >CL in H7; * #E destruct |
---|
625 | | #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 destruct // |
---|
626 | | #H29 #H30 #H31 #H32 #H33 #H34 #H35 #H36 #H37 #H38 #H39 #H40 #H41 @⊥ destruct |
---|
627 | >H35 in CL; #E destruct |
---|
628 | | #H43 #H44 #H45 #H46 #H47 #H48 #H49 #H50 #H51 #H52 @⊥ destruct |
---|
629 | >H48 in CL; #E destruct |
---|
630 | ] |
---|
631 | | @E |
---|
632 | ] |
---|
633 | | #s #tr #s' #d1 #EX #t #CL #T #IH #d2 #T2 #s2 #t2 #E @IH |
---|
634 | [ inversion T2 [ #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 #H13 @⊥ destruct |
---|
635 | >CL in H7; * #E destruct |
---|
636 | | #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 @⊥ destruct |
---|
637 | >H21 in CL; #E destruct |
---|
638 | | #H29 #H30 #H31 #H32 #H33 #H34 #H35 #H36 #H37 #H38 #H39 #H40 #H41 |
---|
639 | whd in H38:(??%??); destruct // |
---|
640 | | #H43 #H44 #H45 #H46 #H47 #H48 #H49 #H50 #H51 #H52 |
---|
641 | whd in H49:(??%??); @⊥ destruct |
---|
642 | ] |
---|
643 | | @E |
---|
644 | ] |
---|
645 | | #s #tr #s' #EX #t #CL #d2 #T2 #s2 #t2 #E whd in E:(??%?); destruct |
---|
646 | inversion T2 [ #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 #H13 @⊥ destruct |
---|
647 | >CL in H7; * #E destruct |
---|
648 | | #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 @⊥ destruct |
---|
649 | >H21 in CL; #E destruct |
---|
650 | | #H29 #H30 #H31 #H32 #H33 #H34 #H35 #H36 #H37 #H38 #H39 #H40 #H41 |
---|
651 | whd in H38:(??%??); destruct // |
---|
652 | | #H43 #H44 #H45 #H46 #H47 #H48 #H49 #H50 #H51 #H52 |
---|
653 | whd in H49:(??%??); @⊥ destruct |
---|
654 | ] |
---|
655 | ] qed. |
---|
656 | |
---|
657 | lemma will_return_not_wrong : ∀ge,d,s,t,s',t'. |
---|
658 | ∀T:will_return ge d s t. |
---|
659 | not_wrong io_out io_in ge s t → |
---|
660 | will_return_end … T = ❬s', t'❭ → |
---|
661 | not_wrong io_out io_in ge s' t'. |
---|
662 | #ge #d #s #t #s' #t' #T elim T |
---|
663 | [ #s #tr #s' #d #EV #t1 #CL #T' #IH #NW #E @IH |
---|
664 | [ inversion NW |
---|
665 | [ #H1 #H2 #H3 #H4 #H5 destruct |
---|
666 | | #H7 #H8 #H9 #H10 #H11 #H12 #H13 #H14 #H15 destruct // |
---|
667 | ] |
---|
668 | | @E |
---|
669 | ] |
---|
670 | | #s #tr #s' #d #EV #t1 #CL #T' #IH #NW #E @IH |
---|
671 | [ inversion NW [ #H1 #H2 #H3 #H4 #H5 destruct | #H7 #H8 #H9 #H10 #H11 #H12 #H13 #H14 #H15 destruct // ] |
---|
672 | | @E |
---|
673 | ] |
---|
674 | | #s #tr #s' #d #EV #t1 #CL #T' #IH #NW #E @IH |
---|
675 | [ inversion NW [ #H1 #H2 #H3 #H4 #H5 destruct | #H7 #H8 #H9 #H10 #H11 #H12 #H13 #H14 #H15 destruct // ] |
---|
676 | | @E |
---|
677 | ] |
---|
678 | | #s #tr #s' #d #t1 #CL #NW #E normalize in E; destruct |
---|
679 | inversion NW [ #H1 #H2 #H3 #H4 #H5 destruct | #H7 #H8 #H9 #H10 #H11 #H12 #H13 #H14 #H15 destruct // ] |
---|
680 | ] qed. |
---|
681 | |
---|
682 | |
---|
683 | lemma will_return_lower : ∀ge,d,s,t. |
---|
684 | will_return ge d s t → |
---|
685 | ∀d'. d' ≤ d → |
---|
686 | will_return ge d' s t. |
---|
687 | #ge #d0 #s0 #t0 #TM elim TM |
---|
688 | [ #s #tr #s' #d #EX #tr #CL #TM1 #IH #d' #LE % /2/ |
---|
689 | | #s #tr #s' #d #EX #tr #CL #TM1 #IH #d' #LE %2 // @IH /2/ |
---|
690 | | #s #tr #s' #d #EX #tr #CL #TM1 #IH * |
---|
691 | [ #LE @wr_base // |
---|
692 | | #d' #LE %3 // @IH /2/ |
---|
693 | ] |
---|
694 | | #s #tr #s' #EX #tr #CL * |
---|
695 | [ #_ @wr_base // |
---|
696 | | #d' #LE @⊥ /2/ |
---|
697 | ] |
---|
698 | ] qed. |
---|
699 | |
---|
700 | (* We require that labels appear after branch instructions and at the start of |
---|
701 | functions. The first is required for preciseness, the latter for soundness. |
---|
702 | We will make a separate requirement for there to be a finite number of steps |
---|
703 | between labels to catch loops for soundness (is this sufficient?). *) |
---|
704 | |
---|
705 | definition well_cost_labelled_statement : ∀f:internal_function. ∀s. labels_present (f_graph f) s → Prop ≝ |
---|
706 | λf,s. match s return λs. labels_present ? s → Prop with |
---|
707 | [ St_cond _ l1 l2 ⇒ λH. |
---|
708 | is_cost_label (lookup_present … (f_graph f) l1 ?) = true ∧ |
---|
709 | is_cost_label (lookup_present … (f_graph f) l2 ?) = true |
---|
710 | | St_jumptable _ ls ⇒ λH. |
---|
711 | (* I did have a dependent version of All here, but it's a pain. *) |
---|
712 | All … (λl. ∃H. is_cost_label (lookup_present … (f_graph f) l H) = true) ls |
---|
713 | | _ ⇒ λ_. True |
---|
714 | ]. whd in H; |
---|
715 | [ @(proj1 … H) |
---|
716 | | @(proj2 … H) |
---|
717 | ] qed. |
---|
718 | |
---|
719 | definition well_cost_labelled_fn : internal_function → Prop ≝ |
---|
720 | λf. (∀l. ∀H:present … (f_graph f) l. |
---|
721 | well_cost_labelled_statement f (lookup_present … (f_graph f) l H) (f_closed f l …)) ∧ |
---|
722 | is_cost_label (lookup_present … (f_graph f) (f_entry f) ?) = true. |
---|
723 | [ @lookup_lookup_present | cases (f_entry f) // ] qed. |
---|
724 | |
---|
725 | (* We need to ensure that any code we come across is well-cost-labelled. We may |
---|
726 | get function code from either the global environment or the state. *) |
---|
727 | |
---|
728 | definition well_cost_labelled_ge : genv → Prop ≝ |
---|
729 | λge. ∀b,f. find_funct_ptr … ge b = Some ? (Internal ? f) → well_cost_labelled_fn f. |
---|
730 | |
---|
731 | definition well_cost_labelled_state : state → Prop ≝ |
---|
732 | λs. match s with |
---|
733 | [ State f fs m ⇒ well_cost_labelled_fn (func f) ∧ All ? (λf. well_cost_labelled_fn (func f)) fs |
---|
734 | | Callstate fd _ _ fs _ ⇒ match fd with [ Internal fn ⇒ well_cost_labelled_fn fn | External _ ⇒ True ] ∧ |
---|
735 | All ? (λf. well_cost_labelled_fn (func f)) fs |
---|
736 | | Returnstate _ _ fs _ ⇒ All ? (λf. well_cost_labelled_fn (func f)) fs |
---|
737 | | Finalstate _ ⇒ True |
---|
738 | ]. |
---|
739 | |
---|
740 | lemma well_cost_labelled_state_step : ∀ge,s,tr,s'. |
---|
741 | eval_statement ge s = Value ??? 〈tr,s'〉 → |
---|
742 | well_cost_labelled_ge ge → |
---|
743 | well_cost_labelled_state s → |
---|
744 | well_cost_labelled_state s'. |
---|
745 | #ge #s #tr' #s' #EV cases (eval_preserves … EV) |
---|
746 | [ #ge #f #f' #fs #m #m' * #func #locals #next #next_ok #sp #retdst #locals' #next' #next_ok' #Hge * #H1 #H2 % // |
---|
747 | | #ge #f #fs #m * #fn #args #f' #dst * #func #locals #next #next_ok #sp #retdst #locals' #next' #next_ok' #b #Hfn #Hge * #H1 #H2 % /2/ |
---|
748 | (* |
---|
749 | | #ge #f #fs #m * #fn #args #f' #dst #m' #b #Hge * #H1 #H2 % /2/ |
---|
750 | *) |
---|
751 | | #ge #fn #locals #next #nok #sp #fs #m #args #dst #m' #Hge * #H1 #H2 % /2/ |
---|
752 | | #ge #f #fs #m #rtv #dst #m' #Hge * #H1 #H2 @H2 |
---|
753 | | #ge #f #fs #rtv #dst #f' #m * #func #locals #next #nok #sp #retdst #locals' #next' #nok' #Hge * #H1 #H2 % // |
---|
754 | | // |
---|
755 | ] qed. |
---|
756 | |
---|
757 | lemma rtlabs_jump_inv : ∀s. |
---|
758 | RTLabs_classify s = cl_jump → |
---|
759 | ∃f,fs,m. s = State f fs m ∧ |
---|
760 | let stmt ≝ lookup_present ?? (f_graph (func f)) (next f) (next_ok f) in |
---|
761 | (∃r,l1,l2. stmt = St_cond r l1 l2) ∨ (∃r,ls. stmt = St_jumptable r ls). |
---|
762 | * |
---|
763 | [ #f #fs #m #E |
---|
764 | %{f} %{fs} %{m} % |
---|
765 | [ @refl |
---|
766 | | whd in E:(??%?); cases (lookup_present ? statement ???) in E ⊢ %; |
---|
767 | try (normalize try #A try #B try #C try #D try #F try #G try #H try #I try #J destruct) |
---|
768 | [ %1 %{A} %{B} %{C} @refl |
---|
769 | | %2 %{A} %{B} @refl |
---|
770 | ] |
---|
771 | ] |
---|
772 | | normalize #H1 #H2 #H3 #H4 #H5 #H6 destruct |
---|
773 | | normalize #H8 #H9 #H10 #H11 #H12 destruct |
---|
774 | | #r #E normalize in E; destruct |
---|
775 | ] qed. |
---|
776 | |
---|
777 | lemma well_cost_labelled_jump : ∀ge,s,tr,s'. |
---|
778 | eval_statement ge s = Value ??? 〈tr,s'〉 → |
---|
779 | well_cost_labelled_state s → |
---|
780 | RTLabs_classify s = cl_jump → |
---|
781 | RTLabs_cost s' = true. |
---|
782 | #ge #s #tr #s' #EV #H #CL |
---|
783 | cases (rtlabs_jump_inv s CL) |
---|
784 | #fr * #fs * #m * #Es * |
---|
785 | [ * #r * #l1 * #l2 #Estmt |
---|
786 | >Es in H; whd in ⊢ (% → ?); * * #Hbody #_ #Hfs |
---|
787 | >Es in EV; whd in ⊢ (??%? → ?); generalize in ⊢ (??(?%)? → ?); |
---|
788 | >Estmt #LP whd in ⊢ (??%? → ?); |
---|
789 | (* replace with lemma on successors? *) |
---|
790 | @bind_res_value #v #Ev @bind_ok * #Eb whd in ⊢ (??%? → ?); #E destruct |
---|
791 | lapply (Hbody (next fr) (next_ok fr)) |
---|
792 | generalize in ⊢ (???% → ?); |
---|
793 | >Estmt #LP' |
---|
794 | whd in ⊢ (% → ?); |
---|
795 | * #H1 #H2 [ @H1 | @H2 ] |
---|
796 | | * #r * #ls #Estmt |
---|
797 | >Es in H; whd in ⊢ (% → ?); * * #Hbody #_ #Hfs |
---|
798 | >Es in EV; whd in ⊢ (??%? → ?); generalize in ⊢ (??(?%)? → ?); |
---|
799 | >Estmt #LP whd in ⊢ (??%? → ?); |
---|
800 | (* replace with lemma on successors? *) |
---|
801 | @bind_res_value #a cases a [ | #sz #i | #f | | #ptr ] #Ea whd in ⊢ (??%? → ?); |
---|
802 | [ 2: (* later *) |
---|
803 | | *: #E destruct |
---|
804 | ] |
---|
805 | lapply (Hbody (next fr) (next_ok fr)) |
---|
806 | generalize in ⊢ (???% → ?); >Estmt #LP' whd in ⊢ (% → ?); #CP |
---|
807 | generalize in ⊢ (??(?%)? → ?); |
---|
808 | cases (nth_opt label (nat_of_bitvector (bitsize_of_intsize sz) i) ls) in ⊢ (???% → ??(match % with [_⇒?|_⇒?]?)? → ?); |
---|
809 | [ #E1 #E2 whd in E2:(??%?); destruct |
---|
810 | | #l' #E1 #E2 whd in E2:(??%?); destruct |
---|
811 | cases (All_nth ???? CP ? E1) |
---|
812 | #H1 #H2 @H2 |
---|
813 | ] |
---|
814 | ] qed. |
---|
815 | |
---|
816 | lemma rtlabs_call_inv : ∀s. |
---|
817 | RTLabs_classify s = cl_call → |
---|
818 | ∃fd,args,dst,stk,m. s = Callstate fd args dst stk m. |
---|
819 | * [ #f #fs #m whd in ⊢ (??%? → ?); |
---|
820 | cases (lookup_present … (next f) (next_ok f)) normalize |
---|
821 | try #A try #B try #C try #D try #E try #F try #G try #I try #J destruct |
---|
822 | | #fd #args #dst #stk #m #E %{fd} %{args} %{dst} %{stk} %{m} @refl |
---|
823 | | normalize #H411 #H412 #H413 #H414 #H415 destruct |
---|
824 | | normalize #H1 #H2 destruct |
---|
825 | ] qed. |
---|
826 | |
---|
827 | lemma well_cost_labelled_call : ∀ge,s,tr,s'. |
---|
828 | eval_statement ge s = Value ??? 〈tr,s'〉 → |
---|
829 | well_cost_labelled_state s → |
---|
830 | RTLabs_classify s = cl_call → |
---|
831 | RTLabs_cost s' = true. |
---|
832 | #ge #s #tr #s' #EV #WCL #CL |
---|
833 | cases (rtlabs_call_inv s CL) |
---|
834 | #fd * #args * #dst * #stk * #m #E >E in EV WCL; |
---|
835 | whd in ⊢ (??%? → % → ?); |
---|
836 | cases fd |
---|
837 | [ #fn whd in ⊢ (??%? → % → ?); |
---|
838 | @bind_res_value #lcl #Elcl cases (alloc m O (f_stacksize fn) XData) |
---|
839 | #m' #b whd in ⊢ (??%? → ?); #E' destruct |
---|
840 | * whd in ⊢ (% → ?); * #WCL1 #WCL2 #WCL3 |
---|
841 | @WCL2 |
---|
842 | | #fn whd in ⊢ (??%? → % → ?); |
---|
843 | @bindIO_value #evargs #Eargs |
---|
844 | whd in ⊢ (??%? → ?); |
---|
845 | #E' destruct |
---|
846 | ] qed. |
---|
847 | |
---|
848 | |
---|
849 | (* The preservation of (most of) the stack is useful to show as_after_return. |
---|
850 | We do this by showing that during the execution of a function the lower stack |
---|
851 | frames never change, and that after returning from the function we preserve |
---|
852 | the identity of the next instruction to execute. |
---|
853 | |
---|
854 | Note: since this was first written I've introduced the shadow stack of |
---|
855 | function blocks. It might be possible to replace some or all of the stack |
---|
856 | preservation with that. |
---|
857 | *) |
---|
858 | |
---|
859 | inductive stack_of_state : list frame → state → Prop ≝ |
---|
860 | | sos_State : ∀f,fs,m. stack_of_state fs (State f fs m) |
---|
861 | | sos_Callstate : ∀fd,args,dst,f,fs,m. stack_of_state fs (Callstate fd args dst (f::fs) m) |
---|
862 | | sos_Returnstate : ∀rtv,dst,fs,m. stack_of_state fs (Returnstate rtv dst fs m) |
---|
863 | . |
---|
864 | |
---|
865 | inductive stack_preserved : trace_ends_with_ret → state → state → Prop ≝ |
---|
866 | | sp_normal : ∀fs,s1,s2. |
---|
867 | stack_of_state fs s1 → |
---|
868 | stack_of_state fs s2 → |
---|
869 | stack_preserved doesnt_end_with_ret s1 s2 |
---|
870 | | sp_finished : ∀s1,f,f',fs,m. |
---|
871 | next f = next f' → |
---|
872 | frame_rel f f' → |
---|
873 | stack_of_state (f::fs) s1 → |
---|
874 | stack_preserved ends_with_ret s1 (State f' fs m) |
---|
875 | | sp_stop : ∀s1,r. |
---|
876 | stack_of_state [ ] s1 → |
---|
877 | stack_preserved ends_with_ret s1 (Finalstate r) |
---|
878 | | sp_top : ∀fd,args,dst,m,r. |
---|
879 | stack_preserved doesnt_end_with_ret (Callstate fd args dst [ ] m) (Finalstate r) |
---|
880 | . |
---|
881 | |
---|
882 | discriminator list. |
---|
883 | |
---|
884 | lemma stack_of_state_eq : ∀fs,fs',s. |
---|
885 | stack_of_state fs s → |
---|
886 | stack_of_state fs' s → |
---|
887 | fs = fs'. |
---|
888 | #fs0 #fs0' #s0 * |
---|
889 | [ #f #fs #m #H inversion H |
---|
890 | #a #b #c #d try #e try #g try #h try #i try #j destruct @refl |
---|
891 | | #fd #args #dst #f #fs #m #H inversion H |
---|
892 | #a #b #c #d try #e try #g try #h try #i try #j destruct @refl |
---|
893 | | #rtv #dst #fs #m #H inversion H |
---|
894 | #a #b #c #d try #e try #g try #h try #i try #j destruct @refl |
---|
895 | ] qed. |
---|
896 | |
---|
897 | lemma stack_preserved_final : ∀e,r,s. |
---|
898 | ¬stack_preserved e (Finalstate r) s. |
---|
899 | #e #r #s % #H inversion H |
---|
900 | [ #H184 #H185 #H186 #SOS #H188 #H189 #H190 #H191 #H192 destruct |
---|
901 | inversion SOS #a #b #c #d #e #f try #g try #h destruct |
---|
902 | | #H194 #H195 #H196 #H197 #H198 #H199 #H200 #SOS #H201 #H202 #H203 #H204 destruct |
---|
903 | inversion SOS #a #b #c #d #e #f try #g try #h destruct |
---|
904 | | #s' #r' #SOS #E1 #E2 #E3 #E4 destruct |
---|
905 | inversion SOS #a #b #c #d #e #f try #g try #h destruct |
---|
906 | | #H24 #H25 #H26 #H27 #H28 #H29 #H30 #H31 #H32 destruct |
---|
907 | ] qed. |
---|
908 | |
---|
909 | lemma stack_preserved_join : ∀e,s1,s2,s3. |
---|
910 | stack_preserved doesnt_end_with_ret s1 s2 → |
---|
911 | stack_preserved e s2 s3 → |
---|
912 | stack_preserved e s1 s3. |
---|
913 | #e1 #s1 #s2 #s3 #H1 inversion H1 |
---|
914 | [ #fs #s1' #s2' #S1 #S2 #E1 #E2 #E3 #E4 destruct |
---|
915 | #H2 inversion H2 |
---|
916 | [ #fs' #s1'' #s2'' #S1' #S2' #E1 #E2 #E3 #E4 destruct |
---|
917 | @(sp_normal fs) // <(stack_of_state_eq … S1' S2) // |
---|
918 | | #s1'' #f #f' #fs' #m #N #F #S1' #E1 #E2 #E3 #E4 destruct |
---|
919 | @(sp_finished … N) >(stack_of_state_eq … S1' S2) // |
---|
920 | | #s1'' #r #S1'' #E1 #E2 #E3 #E4 destruct @sp_stop >(stack_of_state_eq … S1'' S2) // |
---|
921 | | #fd #args #dst #m #r #E1 #E2 #E3 #E4 destruct |
---|
922 | inversion S2 |
---|
923 | [ #H34 #H35 #H36 #H37 #H38 #H39 destruct |
---|
924 | | #fd' #args' #dst' #f #fs' #m' #E1 #E2 #E3 destruct |
---|
925 | | #H41 #H42 #H43 #H44 #H45 #H46 #H47 destruct |
---|
926 | ] |
---|
927 | ] |
---|
928 | | #H25 #H26 #H27 #H28 #H29 #H30 #H31 #H32 #H33 #H34 #H35 #H36 destruct |
---|
929 | | #H19 #H20 #H21 #H22 #H23 #H24 #H25 destruct #H |
---|
930 | cases (stack_preserved_final … H) #r #E destruct |
---|
931 | | #fd #args #dst #m #r #E1 #E2 #E3 #E4 destruct #F @⊥ |
---|
932 | @(absurd … F) // |
---|
933 | ] qed. |
---|
934 | |
---|
935 | lemma stack_preserved_return : ∀ge,s1,s2,tr. |
---|
936 | RTLabs_classify s1 = cl_return → |
---|
937 | eval_statement ge s1 = Value ??? 〈tr,s2〉 → |
---|
938 | stack_preserved ends_with_ret s1 s2. |
---|
939 | #ge * |
---|
940 | [ #f #fs #m #s2 #tr #E @⊥ whd in E:(??%?); |
---|
941 | cases (lookup_present ??? (next f) (next_ok f)) in E; |
---|
942 | normalize #a try #b try #c try #d try #e try #f try #g try #i try #j destruct |
---|
943 | | #fd #args #dst #fs #m #s2 #tr #E normalize in E; destruct |
---|
944 | | #res #dst * |
---|
945 | [ #m #s2 #tr #_ #EV whd in EV:(??%?); cases res in EV; |
---|
946 | [ normalize #EV destruct | * [ 2: * #r normalize #EV destruct /2/ | *: normalize #a try #b destruct ] ] |
---|
947 | | #f #fs #m #s2 #tr #_ whd in ⊢ (??%? → ?); @bind_res_value #locals #El #EV |
---|
948 | whd in EV:(??%?); destruct @(sp_finished ? f) // |
---|
949 | cases f // |
---|
950 | ] |
---|
951 | | #r #s2 #tr #E normalize in E; destruct |
---|
952 | ] qed. |
---|
953 | |
---|
954 | lemma stack_preserved_step : ∀ge,s1,s2,tr. |
---|
955 | RTLabs_classify s1 = cl_other ∨ RTLabs_classify s1 = cl_jump → |
---|
956 | eval_statement ge s1 = Value ??? 〈tr,s2〉 → |
---|
957 | stack_preserved doesnt_end_with_ret s1 s2. |
---|
958 | #ge0 #s1 #s2 #tr #CL #EV inversion (eval_preserves … EV) |
---|
959 | [ #ge #f #f' #fs #m #m' #F #E1 #E2 #E3 #E4 destruct /2/ |
---|
960 | | #ge #f #fs #m #fd #args #f' #dst #F #b #FFP #E1 #E2 #E3 #E4 /2/ |
---|
961 | | #ge #fn #locals #next #nok #sp #fs #m #args #dst #m' #E1 #E2 #E3 #E4 destruct |
---|
962 | normalize in CL; cases CL #E destruct |
---|
963 | | #ge #f #fs #m #rtv #dst #m' #E1 #E2 #E3 #E4 destruct /2/ |
---|
964 | | #ge #f #fs #rtv #dst #f' #m #F #E1 #E2 #E3 #E4 destruct cases CL |
---|
965 | #E normalize in E; destruct |
---|
966 | | #ge #r #dst #m #E1 #E2 destruct @⊥ cases CL normalize #E destruct |
---|
967 | ] qed. |
---|
968 | |
---|
969 | lemma stack_preserved_call : ∀ge,s1,s2,s3,tr. |
---|
970 | RTLabs_classify s1 = cl_call → |
---|
971 | eval_statement ge s1 = Value ??? 〈tr,s2〉 → |
---|
972 | stack_preserved ends_with_ret s2 s3 → |
---|
973 | stack_preserved doesnt_end_with_ret s1 s3. |
---|
974 | #ge #s1 #s2 #s3 #tr #CL #EV #SP |
---|
975 | cases (rtlabs_call_inv … CL) |
---|
976 | #fd * #args * #dst * #stk * #m #E destruct |
---|
977 | inversion SP |
---|
978 | [ #H38 #H39 #H40 #H41 #H42 #H43 #H44 #H45 #H46 destruct |
---|
979 | | #s2' #f #f' #fs #m' #N #F #S #E1 #E2 #E3 #E4 destruct |
---|
980 | inversion (eval_preserves … EV) |
---|
981 | [ #H48 #H49 #H50 #H51 #H52 #H53 #H54 #H55 #H56 #H57 #H58 destruct |
---|
982 | | #H60 #H61 #H62 #H63 #H64 #H65 #H66 #H67 #H68 #H69 #H70 #H71 #H72 #H73 #H74 destruct |
---|
983 | | #ge' #fn #locals #next #nok #sp #fs1 #m1 #args1 #dst1 #m2 #E1 #E2 #E3 #E4 destruct |
---|
984 | inversion S |
---|
985 | [ #fx #fsx #mx #E1 #E2 #E3 destruct /2/ |
---|
986 | | #H76 #H77 #H78 #H79 #H80 #H81 #H82 #H83 #H84 destruct |
---|
987 | | #H86 #H87 #H88 #H89 #H90 #H91 #H92 destruct |
---|
988 | ] |
---|
989 | | #H94 #H95 #H96 #H97 #H98 #H99 #H100 #H101 #H102 #H103 #H104 destruct |
---|
990 | | #H106 #H107 #H108 #H109 #H110 #H111 #H112 #H113 #H114 #H115 #H116 #H117 destruct |
---|
991 | | #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 destruct |
---|
992 | ] |
---|
993 | | #s1 #r #S1 #E1 #E2 #E3 #_ destruct |
---|
994 | inversion (eval_preserves … EV) |
---|
995 | [ #H48 #H49 #H50 #H51 #H52 #H53 #H54 #H55 #H56 #H57 #H58 destruct |
---|
996 | | #H60 #H61 #H62 #H63 #H64 #H65 #H66 #H67 #H68 #H69 #H70 #H71 #H72 #H73 #H74 destruct |
---|
997 | | #ge' #fn #locals #next #nok #sp #fs1 #m1 #args1 #dst1 #m2 #E1 #E2 #E3 #E4 destruct |
---|
998 | inversion S1 |
---|
999 | [ #fx #fsx #mx #E1 #E2 #E3 destruct /2/ |
---|
1000 | | #H76 #H77 #H78 #H79 #H80 #H81 #H82 #H83 #H84 destruct |
---|
1001 | | #H86 #H87 #H88 #H89 #H90 #H91 #H92 destruct |
---|
1002 | ] |
---|
1003 | | #H94 #H95 #H96 #H97 #H98 #H99 #H100 #H101 #H102 #H103 #H104 destruct |
---|
1004 | | #H106 #H107 #H108 #H109 #H110 #H111 #H112 #H113 #H114 #H115 #H116 #H117 destruct |
---|
1005 | | #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 destruct |
---|
1006 | ] |
---|
1007 | | #H49 #H50 #H51 #H52 #H53 #H54 #H55 #H56 #H57 destruct |
---|
1008 | ] qed. |
---|
1009 | |
---|
1010 | lemma RTLabs_after_call : ∀ge.∀s1,s2,s3:RTLabs_state ge.∀tr. |
---|
1011 | ∀CL : RTLabs_classify s1 = cl_call. |
---|
1012 | eval_statement ge s1 = Value ??? 〈tr,s2〉 → |
---|
1013 | stack_preserved ends_with_ret s2 s3 → |
---|
1014 | as_after_return (RTLabs_status ge) «s1,CL» s3. |
---|
1015 | #ge * #s1 #stk1 #M1 * #s2 #stk2 #M2 * #s3 #stk3 #M3 #tr #CL #EV #S23 |
---|
1016 | cases (rtlabs_call_inv … CL) #fn * #args * #dst * #stk * #m #E destruct |
---|
1017 | whd |
---|
1018 | inversion S23 |
---|
1019 | [ #H129 #H130 #H131 #H132 #H133 #H134 #H135 #H136 #H137 destruct |
---|
1020 | | #s2' #f #f' #fs #m' #N #F #S #E1 #E2 #E3 #E4 destruct whd |
---|
1021 | inversion (eval_preserves … EV) |
---|
1022 | [ #H139 #H140 #H141 #H142 #H143 #H144 #H145 #H146 #H147 #H148 #H149 destruct |
---|
1023 | | #H151 #H152 #H153 #H154 #H155 #H156 #H157 #H158 #H159 #H160 #H161 #H162 #H163 #H164 #H165 destruct |
---|
1024 | | #gex #fnx #locals #next #nok #sp #fsx #mx #argsx #dstx #mx' #E1 #E2 #E3 #E4 destruct |
---|
1025 | inversion S |
---|
1026 | [ #fy #fsy #my #E1 #E2 #E3 destruct whd % [ @N | inversion F // ] |
---|
1027 | | #H167 #H168 #H169 #H170 #H171 #H172 #H173 #H174 #H175 destruct |
---|
1028 | | #H177 #H178 #H179 #H180 #H181 #H182 #H183 destruct |
---|
1029 | ] |
---|
1030 | | #H185 #H186 #H187 #H188 #H189 #H190 #H191 #H192 #H193 #H194 #H195 destruct |
---|
1031 | | #H197 #H198 #H199 #H200 #H201 #H202 #H203 #H204 #H205 #H206 #H207 #H208 destruct |
---|
1032 | | #H10 #H11 #H12 #H13 #H14 #H15 #H16 #H17 destruct |
---|
1033 | ] |
---|
1034 | | #s1 #r #S1 #E1 #E2 #E3 #E4 destruct whd |
---|
1035 | inversion (eval_preserves … EV) |
---|
1036 | [ #H59 #H60 #H61 #H62 #H63 #H64 #H65 #H66 #H67 #H68 #H69 destruct |
---|
1037 | | #H71 #H72 #H73 #H74 #H75 #H76 #H77 #H78 #H79 #H80 #H81 #H82 #H83 #H84 #H85 destruct |
---|
1038 | | #ge' #fn' #locals #next #nok #sp #fs #m' #args' #dst' #m'' #E1 #E2 #E3 #E4 destruct |
---|
1039 | inversion S1 |
---|
1040 | [ #H103 #H104 #H105 #H106 #H107 #H108 destruct // |
---|
1041 | | #H110 #H111 #H112 #H113 #H114 #H115 #H116 #H117 #H118 destruct |
---|
1042 | | #H120 #H121 #H122 #H123 #H124 #H125 #H126 destruct |
---|
1043 | ] |
---|
1044 | | #H185 #H186 #H187 #H188 #H189 #H190 #H191 #H192 #H193 #H194 #H195 destruct |
---|
1045 | | #H197 #H198 #H199 #H200 #H201 #H202 #H203 #H204 #H205 #H206 #H207 #H208 destruct |
---|
1046 | | #H10 #H11 #H12 #H13 #H14 #H15 #H16 #H17 destruct |
---|
1047 | ] |
---|
1048 | | #H128 #H129 #H130 #H131 #H132 #H133 #H134 #H135 #H136 destruct |
---|
1049 | ] qed. |
---|
1050 | |
---|
1051 | (* Don't need to know that labels break loops because we have termination. *) |
---|
1052 | |
---|
1053 | (* A bit of mucking around with the depth to avoid proving termination after |
---|
1054 | termination. Note that we keep a proof that our upper bound on the length |
---|
1055 | of the termination proof is respected. *) |
---|
1056 | record trace_result (ge:genv) (depth:nat) (ends:trace_ends_with_ret) |
---|
1057 | (start:RTLabs_state ge) (full:flat_trace io_out io_in ge start) |
---|
1058 | (original_terminates: will_return ge depth start full) |
---|
1059 | (T:RTLabs_state ge → Type[0]) (limit:nat) : Type[0] ≝ |
---|
1060 | { |
---|
1061 | new_state : RTLabs_state ge; |
---|
1062 | remainder : flat_trace io_out io_in ge new_state; |
---|
1063 | cost_labelled : well_cost_labelled_state new_state; |
---|
1064 | new_trace : T new_state; |
---|
1065 | stack_ok : stack_preserved ends start new_state; |
---|
1066 | terminates : match (match ends with [ doesnt_end_with_ret ⇒ S depth | _ ⇒ depth ]) with |
---|
1067 | [ O ⇒ will_return_end … original_terminates = ❬new_state, remainder❭ |
---|
1068 | | S d ⇒ ΣTM:will_return ge d new_state remainder. |
---|
1069 | gt limit (will_return_length … TM) ∧ |
---|
1070 | will_return_end … original_terminates = will_return_end … TM |
---|
1071 | ] |
---|
1072 | }. |
---|
1073 | |
---|
1074 | (* The same with a flag indicating whether the function returned, as opposed to |
---|
1075 | encountering a label. *) |
---|
1076 | record sub_trace_result (ge:genv) (depth:nat) |
---|
1077 | (start:RTLabs_state ge) (full:flat_trace io_out io_in ge start) |
---|
1078 | (original_terminates: will_return ge depth start full) |
---|
1079 | (T:trace_ends_with_ret → RTLabs_state ge → Type[0]) (limit:nat) : Type[0] ≝ |
---|
1080 | { |
---|
1081 | ends : trace_ends_with_ret; |
---|
1082 | trace_res :> trace_result ge depth ends start full original_terminates (T ends) limit |
---|
1083 | }. |
---|
1084 | |
---|
1085 | (* We often return the result from a recursive call with an addition to the |
---|
1086 | structured trace, so we define a couple of functions to help. The bound on |
---|
1087 | the size of the termination proof might need to be relaxed, too. *) |
---|
1088 | |
---|
1089 | definition replace_trace : ∀ge,d,e.∀s1,s2:RTLabs_state ge.∀t1,t2,TM1,TM2,T1,T2,l1,l2. l2 ≥ l1 → |
---|
1090 | ∀r:trace_result ge d e s1 t1 TM1 T1 l1. |
---|
1091 | will_return_end … TM1 = will_return_end … TM2 → |
---|
1092 | T2 (new_state … r) → |
---|
1093 | stack_preserved e s2 (new_state … r) → |
---|
1094 | trace_result ge d e s2 t2 TM2 T2 l2 ≝ |
---|
1095 | λge,d,e,s1,s2,t1,t2,TM1,TM2,T1,T2,l1,l2,lGE,r,TME,trace,SP. |
---|
1096 | mk_trace_result ge d e s2 t2 TM2 T2 l2 |
---|
1097 | (new_state … r) |
---|
1098 | (remainder … r) |
---|
1099 | (cost_labelled … r) |
---|
1100 | trace |
---|
1101 | SP |
---|
1102 | ? |
---|
1103 | (*(match d return λd'.match d' with [ O ⇒ True | S d'' ⇒ ΣTM.l1 > will_return_length ge d'' (new_state … r) (remainder … r) TM] → |
---|
1104 | match d' with [ O ⇒ True | S d'' ⇒ ΣTM.l2 > will_return_length ge d'' (new_state … r) (remainder … r) TM] with |
---|
1105 | [O ⇒ λ_. I | _ ⇒ λTM. «pi1 … TM, ?» ] (terminates ???????? r))*) |
---|
1106 | . |
---|
1107 | cases e in r ⊢ %; |
---|
1108 | [ <TME -TME * cases d in TM1 TM2 ⊢ %; |
---|
1109 | [ #TM1 #TM2 #ns #rem #WCLS #T1NS #SP whd in ⊢ (% → %); #TMS @TMS |
---|
1110 | | #d' #TM1 #TM2 #ns #rem #WCLS #T1NS #SP whd in ⊢ (% → %); * #TMa * #L1 #TME |
---|
1111 | %{TMa} % // @(transitive_le … lGE) @L1 |
---|
1112 | ] |
---|
1113 | | <TME -TME * #ns #rem #WCLS #T1NS #SP whd in ⊢ (% → %); |
---|
1114 | * #TMa * #L1 #TME |
---|
1115 | %{TMa} % // @(transitive_le … lGE) @L1 |
---|
1116 | ] qed. |
---|
1117 | |
---|
1118 | definition replace_sub_trace : ∀ge,d.∀s1,s2:RTLabs_state ge.∀t1,t2,TM1,TM2,T1,T2,l1,l2. l2 ≥ l1 → |
---|
1119 | ∀r:sub_trace_result ge d s1 t1 TM1 T1 l1. |
---|
1120 | will_return_end … TM1 = will_return_end … TM2 → |
---|
1121 | T2 (ends … r) (new_state … r) → |
---|
1122 | stack_preserved (ends … r) s2 (new_state … r) → |
---|
1123 | sub_trace_result ge d s2 t2 TM2 T2 l2 ≝ |
---|
1124 | λge,d,s1,s2,t1,t2,TM1,TM2,T1,T2,l1,l2,lGE,r,TME,trace,SP. |
---|
1125 | mk_sub_trace_result ge d s2 t2 TM2 T2 l2 |
---|
1126 | (ends … r) |
---|
1127 | (replace_trace … lGE … r TME trace SP). |
---|
1128 | |
---|
1129 | (* Small syntax hack to avoid ambiguous input problems. *) |
---|
1130 | definition myge : nat → nat → Prop ≝ ge. |
---|
1131 | |
---|
1132 | let rec make_label_return ge depth (s:RTLabs_state ge) |
---|
1133 | (trace: flat_trace io_out io_in ge s) |
---|
1134 | (ENV_COSTLABELLED: well_cost_labelled_ge ge) |
---|
1135 | (STATE_COSTLABELLED: well_cost_labelled_state s) (* functions in the state *) |
---|
1136 | (STATEMENT_COSTLABEL: RTLabs_cost s = true) (* current statement is a cost label *) |
---|
1137 | (TERMINATES: will_return ge depth s trace) |
---|
1138 | (TIME: nat) |
---|
1139 | (TERMINATES_IN_TIME: myge TIME (plus 2 (times 3 (will_return_length … TERMINATES)))) |
---|
1140 | on TIME : trace_result ge depth ends_with_ret s trace TERMINATES |
---|
1141 | (trace_label_return (RTLabs_status ge) s) |
---|
1142 | (will_return_length … TERMINATES) ≝ |
---|
1143 | |
---|
1144 | match TIME return λTIME. TIME ≥ ? → ? with |
---|
1145 | [ O ⇒ λTERMINATES_IN_TIME. ⊥ |
---|
1146 | | S TIME ⇒ λTERMINATES_IN_TIME. |
---|
1147 | |
---|
1148 | let r ≝ make_label_label ge depth s |
---|
1149 | trace |
---|
1150 | ENV_COSTLABELLED |
---|
1151 | STATE_COSTLABELLED |
---|
1152 | STATEMENT_COSTLABEL |
---|
1153 | TERMINATES |
---|
1154 | TIME ? in |
---|
1155 | match ends … r return λx. trace_result ge depth x s trace TERMINATES (trace_label_label (RTLabs_status ge) x s) ? → |
---|
1156 | trace_result ge depth ends_with_ret s trace TERMINATES (trace_label_return (RTLabs_status ge) s) (will_return_length … TERMINATES) with |
---|
1157 | [ ends_with_ret ⇒ λr. |
---|
1158 | replace_trace … r ? (tlr_base (RTLabs_status ge) s (new_state … r) (new_trace … r)) (stack_ok … r) |
---|
1159 | | doesnt_end_with_ret ⇒ λr. |
---|
1160 | let r' ≝ make_label_return ge depth (new_state … r) |
---|
1161 | (remainder … r) |
---|
1162 | ENV_COSTLABELLED |
---|
1163 | (cost_labelled … r) ? |
---|
1164 | (pi1 … (terminates … r)) TIME ? in |
---|
1165 | replace_trace … r' ? |
---|
1166 | (tlr_step (RTLabs_status ge) s (new_state … r) |
---|
1167 | (new_state … r') (new_trace … r) (new_trace … r')) ? |
---|
1168 | ] (trace_res … r) |
---|
1169 | |
---|
1170 | ] TERMINATES_IN_TIME |
---|
1171 | |
---|
1172 | |
---|
1173 | and make_label_label ge depth (s:RTLabs_state ge) |
---|
1174 | (trace: flat_trace io_out io_in ge s) |
---|
1175 | (ENV_COSTLABELLED: well_cost_labelled_ge ge) |
---|
1176 | (STATE_COSTLABELLED: well_cost_labelled_state s) (* functions in the state *) |
---|
1177 | (STATEMENT_COSTLABEL: RTLabs_cost s = true) (* current statement is a cost label *) |
---|
1178 | (TERMINATES: will_return ge depth s trace) |
---|
1179 | (TIME: nat) |
---|
1180 | (TERMINATES_IN_TIME: myge TIME (plus 1 (times 3 (will_return_length … TERMINATES)))) |
---|
1181 | on TIME : sub_trace_result ge depth s trace TERMINATES |
---|
1182 | (λends. trace_label_label (RTLabs_status ge) ends s) |
---|
1183 | (will_return_length … TERMINATES) ≝ |
---|
1184 | |
---|
1185 | match TIME return λTIME. TIME ≥ ? → ? with |
---|
1186 | [ O ⇒ λTERMINATES_IN_TIME. ⊥ |
---|
1187 | | S TIME ⇒ λTERMINATES_IN_TIME. |
---|
1188 | |
---|
1189 | let r ≝ make_any_label ge depth s trace ENV_COSTLABELLED STATE_COSTLABELLED TERMINATES TIME ? in |
---|
1190 | replace_sub_trace … r ? |
---|
1191 | (tll_base (RTLabs_status ge) (ends … r) s (new_state … r) (new_trace … r) ?) (stack_ok … r) |
---|
1192 | |
---|
1193 | ] TERMINATES_IN_TIME |
---|
1194 | |
---|
1195 | |
---|
1196 | and make_any_label ge depth (s0:RTLabs_state ge) |
---|
1197 | (trace: flat_trace io_out io_in ge s0) |
---|
1198 | (ENV_COSTLABELLED: well_cost_labelled_ge ge) |
---|
1199 | (STATE_COSTLABELLED: well_cost_labelled_state s0) (* functions in the state *) |
---|
1200 | (TERMINATES: will_return ge depth s0 trace) |
---|
1201 | (TIME: nat) |
---|
1202 | (TERMINATES_IN_TIME: myge TIME (times 3 (will_return_length … TERMINATES))) |
---|
1203 | on TIME : sub_trace_result ge depth s0 trace TERMINATES |
---|
1204 | (λends. trace_any_label (RTLabs_status ge) ends s0) |
---|
1205 | (will_return_length … TERMINATES) ≝ |
---|
1206 | |
---|
1207 | match TIME return λTIME. TIME ≥ ? → ? with |
---|
1208 | [ O ⇒ λTERMINATES_IN_TIME. ⊥ |
---|
1209 | | S TIME ⇒ λTERMINATES_IN_TIME. |
---|
1210 | match s0 return λs:RTLabs_state ge. ∀trace:flat_trace io_out io_in ge s. |
---|
1211 | well_cost_labelled_state s → |
---|
1212 | ∀TM:will_return ??? trace. |
---|
1213 | myge ? (times 3 (will_return_length ??? trace TM)) → |
---|
1214 | sub_trace_result ge depth s trace TM (λends. trace_any_label (RTLabs_status ge) ends s) (will_return_length … TM) |
---|
1215 | with [ mk_RTLabs_state s stk mtc0 ⇒ λtrace. |
---|
1216 | match trace return λs,trace. ∀mtc:Ras_Fn_Match ge s stk. |
---|
1217 | well_cost_labelled_state s → |
---|
1218 | ∀TM:will_return ??? trace. |
---|
1219 | myge ? (times 3 (will_return_length ??? trace TM)) → |
---|
1220 | sub_trace_result ge depth (mk_RTLabs_state ge s stk mtc) trace TM (λends. trace_any_label (RTLabs_status ge) ends (mk_RTLabs_state ge s stk mtc)) (will_return_length … TM) with |
---|
1221 | [ ft_stop st FINAL ⇒ |
---|
1222 | λmtc,STATE_COSTLABELLED,TERMINATES,TERMINATES_IN_TIME. ⊥ |
---|
1223 | |
---|
1224 | | ft_step start tr next EV trace' ⇒ λmtc,STATE_COSTLABELLED,TERMINATES,TERMINATES_IN_TIME. |
---|
1225 | let start' ≝ mk_RTLabs_state ge start stk mtc in |
---|
1226 | let next' ≝ next_state ? start' ?? EV in |
---|
1227 | match RTLabs_classify start return λx. RTLabs_classify start = x → sub_trace_result ge depth ??? (λends. trace_any_label (RTLabs_status ge) ends ?) (will_return_length … TERMINATES) with |
---|
1228 | [ cl_other ⇒ λCL. |
---|
1229 | match RTLabs_cost next return λx. RTLabs_cost next = x → sub_trace_result ge depth ??? (λends. trace_any_label (RTLabs_status ge) ends ?) (will_return_length … TERMINATES) with |
---|
1230 | (* We're about to run into a label. *) |
---|
1231 | [ true ⇒ λCS. |
---|
1232 | mk_sub_trace_result ge depth start' ? TERMINATES (λends. trace_any_label (RTLabs_status ge) ends start') ? |
---|
1233 | doesnt_end_with_ret |
---|
1234 | (mk_trace_result ge … next' trace' ? |
---|
1235 | (tal_base_not_return (RTLabs_status ge) start' next' ?? (proj1 … (RTLabs_costed ge next') CS)) ??) |
---|
1236 | (* An ordinary step, keep going. *) |
---|
1237 | | false ⇒ λCS. |
---|
1238 | let r ≝ make_any_label ge depth next' trace' ENV_COSTLABELLED ? (will_return_notfn … TERMINATES) TIME ? in |
---|
1239 | replace_sub_trace ????????????? r ? |
---|
1240 | (tal_step_default (RTLabs_status ge) (ends … r) |
---|
1241 | start' next' (new_state … r) ? (new_trace … r) ? (RTLabs_not_cost ? next' CS)) ? |
---|
1242 | ] (refl ??) |
---|
1243 | |
---|
1244 | | cl_jump ⇒ λCL. |
---|
1245 | mk_sub_trace_result ge depth start' ? TERMINATES (λends. trace_any_label (RTLabs_status ge) ends start') ? |
---|
1246 | doesnt_end_with_ret |
---|
1247 | (mk_trace_result ge … next' trace' ? |
---|
1248 | (tal_base_not_return (RTLabs_status ge) start' next' ???) ??) |
---|
1249 | |
---|
1250 | | cl_call ⇒ λCL. |
---|
1251 | let r ≝ make_label_return ge (S depth) next' trace' ENV_COSTLABELLED ?? (will_return_call … CL TERMINATES) TIME ? in |
---|
1252 | match RTLabs_cost (new_state … r) return λx. RTLabs_cost (new_state … r) = x → sub_trace_result ge depth start' ?? (λends. trace_any_label (RTLabs_status ge) ends ?) (will_return_length … TERMINATES) with |
---|
1253 | (* We're about to run into a label, use base case for call *) |
---|
1254 | [ true ⇒ λCS. |
---|
1255 | mk_sub_trace_result ge depth start' ? TERMINATES (λends. trace_any_label (RTLabs_status ge) ends start') ? |
---|
1256 | doesnt_end_with_ret |
---|
1257 | (mk_trace_result ge … |
---|
1258 | (tal_base_call (RTLabs_status ge) start' next' (new_state … r) |
---|
1259 | ? CL ? (new_trace … r) ((proj1 … (RTLabs_costed …)) … CS)) ??) |
---|
1260 | (* otherwise use step case *) |
---|
1261 | | false ⇒ λCS. |
---|
1262 | let r' ≝ make_any_label ge depth |
---|
1263 | (new_state … r) (remainder … r) ENV_COSTLABELLED ? |
---|
1264 | (pi1 … (terminates … r)) TIME ? in |
---|
1265 | replace_sub_trace … r' ? |
---|
1266 | (tal_step_call (RTLabs_status ge) (ends … r') |
---|
1267 | start' next' (new_state … r) (new_state … r') ? CL ? |
---|
1268 | (new_trace … r) (RTLabs_not_cost … CS) (new_trace … r')) ? |
---|
1269 | ] (refl ??) |
---|
1270 | |
---|
1271 | | cl_return ⇒ λCL. |
---|
1272 | mk_sub_trace_result ge depth start' ? TERMINATES (λends. trace_any_label (RTLabs_status ge) ends start') ? |
---|
1273 | ends_with_ret |
---|
1274 | (mk_trace_result ge … |
---|
1275 | next' |
---|
1276 | trace' |
---|
1277 | ? |
---|
1278 | (tal_base_return (RTLabs_status ge) start' next' ? CL) |
---|
1279 | ? |
---|
1280 | ?) |
---|
1281 | ] (refl ? (RTLabs_classify start)) |
---|
1282 | |
---|
1283 | | ft_wrong start m NF EV ⇒ λmtc,STATE_COSTLABELLED,TERMINATES. ⊥ |
---|
1284 | |
---|
1285 | ] mtc0 ] trace STATE_COSTLABELLED TERMINATES TERMINATES_IN_TIME |
---|
1286 | ] TERMINATES_IN_TIME. |
---|
1287 | |
---|
1288 | [ cases (not_le_Sn_O ?) [ #H @H @TERMINATES_IN_TIME ] |
---|
1289 | | // |
---|
1290 | | // |
---|
1291 | | cases r #H1 #H2 #H3 #H4 #H5 * #H7 * #GT #_ @(le_S_to_le … GT) |
---|
1292 | | cases r #H1 #H2 #H3 #H4 #H5 * #H7 * #_ #EEQ // |
---|
1293 | | @(stack_preserved_join … (stack_ok … r)) // |
---|
1294 | | @(proj2 … (RTLabs_costed ge …)) @(trace_label_label_label … (new_trace … r)) |
---|
1295 | | cases r #H1 #H2 #H3 #H4 #H5 * #H7 * #LT #_ |
---|
1296 | @(le_plus_to_le … 1) @(transitive_le … TERMINATES_IN_TIME) |
---|
1297 | @(transitive_le … (3*(will_return_length … TERMINATES))) |
---|
1298 | [ >commutative_times change with ((S ?) * 3 ≤ ?) >commutative_times |
---|
1299 | @(monotonic_le_times_r 3 … LT) |
---|
1300 | | @le_S @le_S @le_n |
---|
1301 | ] |
---|
1302 | | @le_S_S_to_le @TERMINATES_IN_TIME |
---|
1303 | | cases (not_le_Sn_O ?) [ #H @H @TERMINATES_IN_TIME ] |
---|
1304 | | @le_n |
---|
1305 | | // |
---|
1306 | | @(proj1 … (RTLabs_costed …)) // |
---|
1307 | | @le_S_S_to_le @TERMINATES_IN_TIME |
---|
1308 | | @(wrl_nonzero … TERMINATES_IN_TIME) |
---|
1309 | | (* We can't reach the final state because the function terminates with a |
---|
1310 | return *) |
---|
1311 | inversion TERMINATES |
---|
1312 | [ #H214 #H215 #H216 #H217 #H218 #H219 #H220 #H221 #H222 #H223 #H224 #H225 #_ -TERMINATES -TERMINATES destruct |
---|
1313 | | #H228 #H229 #H230 #H231 #H232 #H233 #H234 #H235 #H236 #H237 #H238 #H239 #H240 -TERMINATES -TERMINATES destruct |
---|
1314 | | #H242 #H243 #H244 #H245 #H246 #H247 #H248 #H249 #H250 #H251 #H252 #H253 #H254 -TERMINATES -TERMINATES destruct |
---|
1315 | | #H256 #H257 #H258 #H259 #H260 #H261 #H262 #H263 #H264 #H265 -TERMINATES -TERMINATES destruct |
---|
1316 | ] |
---|
1317 | | @(will_return_return … CL TERMINATES) |
---|
1318 | | @(stack_preserved_return … EV) // |
---|
1319 | | %{tr} %{EV} @refl |
---|
1320 | | @(well_cost_labelled_state_step … EV) // |
---|
1321 | | whd @(will_return_notfn … TERMINATES) %2 @CL |
---|
1322 | | @(stack_preserved_step … EV) /2/ |
---|
1323 | | %{tr} %{EV} % |
---|
1324 | | %1 whd @CL |
---|
1325 | | @(proj1 … (RTLabs_costed …)) @(well_cost_labelled_jump … EV) // |
---|
1326 | | @(well_cost_labelled_state_step … EV) // |
---|
1327 | | whd cases (terminates ???????? r) #TMr * #LTr #EQr %{TMr} % |
---|
1328 | [ @(transitive_lt … LTr) cases (will_return_call … CL TERMINATES) |
---|
1329 | #TMx * #LT' #_ @LT' |
---|
1330 | | <EQr cases (will_return_call … CL TERMINATES) |
---|
1331 | #TM' * #_ #EQ' @EQ' |
---|
1332 | ] |
---|
1333 | | @(stack_preserved_call … EV (stack_ok … r)) // |
---|
1334 | | %{tr} %{EV} % |
---|
1335 | | @(RTLabs_after_call … next') [2: @EV | skip | // ] |
---|
1336 | | @(cost_labelled … r) |
---|
1337 | | skip |
---|
1338 | | cases r #ns #rm #WS #TLR #SP * #TM * #LT #_ @le_S_to_le |
---|
1339 | @(transitive_lt … LT) |
---|
1340 | cases (will_return_call … CL TERMINATES) #TM' * #LT' #_ @LT' |
---|
1341 | | cases r #ns #rm #WS #TLR #SP * #TM * #_ #EQ <EQ |
---|
1342 | cases (will_return_call … CL TERMINATES) #TM' * #_ #EQ' @sym_eq @EQ' |
---|
1343 | | @(RTLabs_after_call … next') [2: @EV | skip | // ] |
---|
1344 | | %{tr} %{EV} % |
---|
1345 | | @(stack_preserved_join … (stack_ok … r')) @(stack_preserved_call … EV (stack_ok … r)) // |
---|
1346 | | @(cost_labelled … r) |
---|
1347 | | cases r #H72 #H73 #H74 #H75 #HX * #HY * #GT #H78 |
---|
1348 | @(le_plus_to_le … 1) @(transitive_le … TERMINATES_IN_TIME) |
---|
1349 | cases (will_return_call … TERMINATES) in GT; |
---|
1350 | #X * #Y #_ #Z |
---|
1351 | @(transitive_le … (monotonic_lt_times_r 3 … Y)) |
---|
1352 | [ @(transitive_le … (monotonic_lt_times_r 3 … Z)) // |
---|
1353 | | // |
---|
1354 | ] |
---|
1355 | | @(well_cost_labelled_state_step … EV) // |
---|
1356 | | @(well_cost_labelled_call … EV) // |
---|
1357 | | cases (will_return_call … TERMINATES) |
---|
1358 | #TM * #GT #_ @le_S_S_to_le |
---|
1359 | >commutative_times change with ((S ?) * 3 ≤ ?) >commutative_times |
---|
1360 | @(transitive_le … TERMINATES_IN_TIME) |
---|
1361 | @(monotonic_le_times_r 3 … GT) |
---|
1362 | | whd @(will_return_notfn … TERMINATES) %1 @CL |
---|
1363 | | @(stack_preserved_step … EV) /2/ |
---|
1364 | | %{tr} %{EV} % |
---|
1365 | | %2 whd @CL |
---|
1366 | | @(well_cost_labelled_state_step … EV) // |
---|
1367 | | cases (will_return_notfn … TERMINATES) #TM * #GT #_ @(le_S_to_le … GT) |
---|
1368 | | cases (will_return_notfn … TERMINATES) #TM * #_ #EQ @sym_eq @EQ |
---|
1369 | | @CL |
---|
1370 | | %{tr} %{EV} % |
---|
1371 | | @(stack_preserved_join … (stack_ok … r)) @(stack_preserved_step … EV) /2/ |
---|
1372 | | @(well_cost_labelled_state_step … EV) // |
---|
1373 | | %1 @CL |
---|
1374 | | cases (will_return_notfn … TERMINATES) #TM * #GT #_ |
---|
1375 | @le_S_S_to_le |
---|
1376 | @(transitive_le … (monotonic_lt_times_r … GT) TERMINATES_IN_TIME) |
---|
1377 | // |
---|
1378 | | inversion TERMINATES |
---|
1379 | [ #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 #H13 -TERMINATES -TERMINATES destruct |
---|
1380 | | #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 #H28 #H29 -TERMINATES -TERMINATES destruct |
---|
1381 | | #H33 #H34 #H35 #H36 #H37 #H38 #H39 #H40 #H41 #H42 #H43 #H44 #H45 -TERMINATES -TERMINATES destruct |
---|
1382 | | #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 -TERMINATES -TERMINATES destruct |
---|
1383 | ] |
---|
1384 | ] qed. |
---|
1385 | |
---|
1386 | (* We can initialise TIME with a suitably large value based on the length of the |
---|
1387 | termination proof. *) |
---|
1388 | let rec make_label_return' ge depth (s:RTLabs_state ge) |
---|
1389 | (trace: flat_trace io_out io_in ge s) |
---|
1390 | (ENV_COSTLABELLED: well_cost_labelled_ge ge) |
---|
1391 | (STATE_COSTLABELLED: well_cost_labelled_state s) (* functions in the state *) |
---|
1392 | (STATEMENT_COSTLABEL: RTLabs_cost s = true) (* current statement is a cost label *) |
---|
1393 | (TERMINATES: will_return ge depth s trace) |
---|
1394 | : trace_result ge depth ends_with_ret s trace TERMINATES (trace_label_return (RTLabs_status ge) s) (will_return_length … TERMINATES) ≝ |
---|
1395 | make_label_return ge depth s trace ENV_COSTLABELLED STATE_COSTLABELLED STATEMENT_COSTLABEL TERMINATES |
---|
1396 | (2 + 3 * will_return_length … TERMINATES) ?. |
---|
1397 | @le_n |
---|
1398 | qed. |
---|
1399 | |
---|
1400 | (* Tail-calls would not be handled properly (which means that if we try to show the |
---|
1401 | full version with non-termination we'll fail because calls and returns aren't |
---|
1402 | balanced. |
---|
1403 | *) |
---|
1404 | |
---|
1405 | inductive inhabited (T:Type[0]) : Prop ≝ |
---|
1406 | | witness : T → inhabited T. |
---|
1407 | |
---|
1408 | (* We also require that program's traces are soundly labelled: for any state |
---|
1409 | in the execution, we can give a distance to a labelled state or termination. |
---|
1410 | |
---|
1411 | Note that this differs from the syntactic notions in earlier languages |
---|
1412 | because it is a global property. In principle, we would have a loop broken |
---|
1413 | only by a call to a function (which necessarily has a label) and no local |
---|
1414 | cost label. |
---|
1415 | *) |
---|
1416 | |
---|
1417 | let rec nth_state ge s |
---|
1418 | (trace: flat_trace io_out io_in ge s) |
---|
1419 | n |
---|
1420 | on n : option state ≝ |
---|
1421 | match n with |
---|
1422 | [ O ⇒ Some ? s |
---|
1423 | | S n' ⇒ |
---|
1424 | match trace with |
---|
1425 | [ ft_step _ _ s' _ trace' ⇒ nth_state ge s' trace' n' |
---|
1426 | | _ ⇒ None ? |
---|
1427 | ] |
---|
1428 | ]. |
---|
1429 | |
---|
1430 | definition soundly_labelled_trace : ∀ge,s. flat_trace io_out io_in ge s → Prop ≝ |
---|
1431 | λge,s,trace. ∀n.∃m. ∀s'. nth_state ge s trace (n+m) = Some ? s' → RTLabs_cost s' = true. |
---|
1432 | |
---|
1433 | lemma soundly_labelled_step : ∀ge,s,tr,s',EV,trace'. |
---|
1434 | soundly_labelled_trace ge s (ft_step … ge s tr s' EV trace') → |
---|
1435 | soundly_labelled_trace ge s' trace'. |
---|
1436 | #ge #s #tr #s' #EV #trace' #H |
---|
1437 | #n cases (H (S n)) #m #H' %{m} @H' |
---|
1438 | qed. |
---|
1439 | |
---|
1440 | (* Define a notion of sound labellings of RTLabs programs. *) |
---|
1441 | |
---|
1442 | let rec successors (s : statement) : list label ≝ |
---|
1443 | match s with |
---|
1444 | [ St_skip l ⇒ [l] |
---|
1445 | | St_cost _ l ⇒ [l] |
---|
1446 | | St_const _ _ _ l ⇒ [l] |
---|
1447 | | St_op1 _ _ _ _ _ l ⇒ [l] |
---|
1448 | | St_op2 _ _ _ _ _ _ _ l ⇒ [l] |
---|
1449 | | St_load _ _ _ l ⇒ [l] |
---|
1450 | | St_store _ _ _ l ⇒ [l] |
---|
1451 | | St_call_id _ _ _ l ⇒ [l] |
---|
1452 | | St_call_ptr _ _ _ l ⇒ [l] |
---|
1453 | (* |
---|
1454 | | St_tailcall_id _ _ ⇒ [ ] |
---|
1455 | | St_tailcall_ptr _ _ ⇒ [ ] |
---|
1456 | *) |
---|
1457 | | St_cond _ l1 l2 ⇒ [l1; l2] |
---|
1458 | | St_jumptable _ ls ⇒ ls |
---|
1459 | | St_return ⇒ [ ] |
---|
1460 | ]. |
---|
1461 | |
---|
1462 | definition actual_successor : state → option label ≝ |
---|
1463 | λs. match s with |
---|
1464 | [ State f fs m ⇒ Some ? (next f) |
---|
1465 | | Callstate _ _ _ fs _ ⇒ match fs with [ cons f _ ⇒ Some ? (next f) | _ ⇒ None ? ] |
---|
1466 | | Returnstate _ _ _ _ ⇒ None ? |
---|
1467 | | Finalstate _ ⇒ None ? |
---|
1468 | ]. |
---|
1469 | |
---|
1470 | lemma nth_opt_Exists : ∀A,n,l,a. |
---|
1471 | nth_opt A n l = Some A a → |
---|
1472 | Exists A (λa'. a' = a) l. |
---|
1473 | #A #n elim n |
---|
1474 | [ * [ #a #E normalize in E; destruct | #a #l #a' #E normalize in E; destruct % // ] |
---|
1475 | | #m #IH * |
---|
1476 | [ #a #E normalize in E; destruct |
---|
1477 | | #a #l #a' #E %2 @IH @E |
---|
1478 | ] |
---|
1479 | ] qed. |
---|
1480 | |
---|
1481 | lemma eval_successor : ∀ge,f,fs,m,tr,s'. |
---|
1482 | eval_statement ge (State f fs m) = Value ??? 〈tr,s'〉 → |
---|
1483 | RTLabs_classify s' = cl_return ∨ |
---|
1484 | ∃l. actual_successor s' = Some ? l ∧ Exists ? (λl0. l0 = l) (successors (lookup_present … (f_graph (func f)) (next f) (next_ok f))). |
---|
1485 | #ge * #func #locals #next #next_ok #sp #dst #fs #m #tr #s' |
---|
1486 | whd in ⊢ (??%? → ?); |
---|
1487 | generalize in ⊢ (??(?%)? → ?); cases (lookup_present ??? next next_ok) |
---|
1488 | [ #l #LP whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // % // |
---|
1489 | | #cl #l #LP whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // % // |
---|
1490 | | #ty #r #c #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev @bind_ok #locals' #El whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // % // |
---|
1491 | | #ty #ty' #op #r1 #r2 #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev @bind_ok #v' #Ev' @bind_ok #locals' #El whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // % // |
---|
1492 | | #ty1 #ty2 #ty' #op #r1 #r2 #r3 #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v1 #Ev1 @bind_ok #v2 #Ev2 @bind_ok #v' #Ev' @bind_ok #locals' #El whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // % // |
---|
1493 | | #ch #r1 #r2 #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v1 #Ev1 @bind_ok #v2 #Ev2 @bind_ok #locals' #El whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // % // |
---|
1494 | | #ch #r1 #r2 #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v1 #Ev1 @bind_ok #v2 #Ev2 @bind_ok #m' #Em whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // % // |
---|
1495 | | #id #rs #r #l #LP whd in ⊢ (??%? → ?); @bind_res_value #b #Eb @bind_ok #fd #Efd @bind_ok #vs #Evs whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // % // |
---|
1496 | | #r #rs #r' #l #LP whd in ⊢ (??%? → ?); @bind_res_value #fv #Efv @bind_ok #fd #Efd @bind_ok #vs #Evs whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // % // |
---|
1497 | | #r #l1 #l2 #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev @bind_ok #b #Eb whd in ⊢ (??%? → ?); #E destruct %2 cases b [ %{l1} | %{l2} ] % // [ % | %2 %] // |
---|
1498 | | #r #ls #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev |
---|
1499 | cases v [ #E normalize in E; destruct | #sz #i | #f #E normalize in E; destruct | #E normalize in E; destruct | #p #E normalize in E; destruct ] |
---|
1500 | whd in ⊢ (??%? → ?); |
---|
1501 | generalize in ⊢ (??(?%)? → ?); |
---|
1502 | cases (nth_opt label (nat_of_bitvector (bitsize_of_intsize sz) i) ls) in ⊢ (???% → ??(match % with [ _ ⇒ ? | _ ⇒ ? ] ?)? → ?); |
---|
1503 | [ #e #E normalize in E; destruct |
---|
1504 | | #l #El whd in ⊢ (??%? → ?); #E destruct %2 %{l} % // @(nth_opt_Exists … El) |
---|
1505 | ] |
---|
1506 | | #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev whd in ⊢ (??%? → ?); #E destruct %1 @refl |
---|
1507 | ] qed. |
---|
1508 | |
---|
1509 | definition steps_for_statement : statement → nat ≝ |
---|
1510 | λs. S (match s with [ St_call_id _ _ _ _ ⇒ 1 | St_call_ptr _ _ _ _ ⇒ 1 | St_return ⇒ 1 | _ ⇒ 0 ]). |
---|
1511 | |
---|
1512 | inductive bound_on_steps_to_cost (g:graph statement) : label → nat → Prop ≝ |
---|
1513 | | bostc_here : ∀l,n,H. is_cost_label (lookup_present … g l H) → bound_on_steps_to_cost g l n |
---|
1514 | | bostc_later : ∀l,n. bound_on_steps_to_cost1 g l n → bound_on_steps_to_cost g l n |
---|
1515 | with bound_on_steps_to_cost1 : label → nat → Prop ≝ |
---|
1516 | | bostc_step : ∀l,n,H. |
---|
1517 | let stmt ≝ lookup_present … g l H in |
---|
1518 | (∀l'. Exists label (λl0. l0 = l') (successors stmt) → |
---|
1519 | bound_on_steps_to_cost g l' n) → |
---|
1520 | bound_on_steps_to_cost1 g l (steps_for_statement stmt + n). |
---|
1521 | |
---|
1522 | (* |
---|
1523 | lemma steps_to_label_bound_inv : ∀g,l,n. |
---|
1524 | steps_to_label_bound g l n → |
---|
1525 | ∀H. let stmt ≝ lookup_present … g l H in |
---|
1526 | ∃n'. n = steps_for_statement stmt + n' ∧ |
---|
1527 | (∀l'. Exists label (λl0. l0 = l') (successors stmt) → |
---|
1528 | (∃H'. bool_to_Prop (is_cost_label (lookup_present … g l' H'))) ∨ |
---|
1529 | steps_to_label_bound g l' n'). |
---|
1530 | #g #l0 #n0 #S inversion S #l #n #H #IH #E1 #E2 #_ destruct #H' |
---|
1531 | % [2: % [ @refl | #l' #EX cases (IH l' EX) /2/ ] | skip ] |
---|
1532 | qed. |
---|
1533 | *) |
---|
1534 | |
---|
1535 | (* |
---|
1536 | definition soundly_labelled_pc ≝ λg,l. ∃n. steps_to_label_bound g l n. |
---|
1537 | |
---|
1538 | let rec soundly_labelled_fn (fn : internal_function) : Prop ≝ |
---|
1539 | soundly_labelled_pc (f_graph fn) (f_entry fn). |
---|
1540 | |
---|
1541 | |
---|
1542 | definition soundly_labelled_frame : frame → Prop ≝ |
---|
1543 | λf. soundly_labelled_pc (f_graph (func f)) (next f). |
---|
1544 | |
---|
1545 | definition soundly_labelled_state : state → Prop ≝ |
---|
1546 | λs. match s with |
---|
1547 | [ State f _ _ ⇒ soundly_labelled_frame f |
---|
1548 | | Callstate _ _ _ stk _ ⇒ match stk with [ nil ⇒ False | cons f _ ⇒ soundly_labelled_frame f ] |
---|
1549 | | Returnstate _ _ stk _ ⇒ match stk with [ nil ⇒ False | cons f _ ⇒ soundly_labelled_frame f ] |
---|
1550 | ]. |
---|
1551 | *) |
---|
1552 | definition frame_bound_on_steps_to_cost : frame → nat → Prop ≝ |
---|
1553 | λf. bound_on_steps_to_cost (f_graph (func f)) (next f). |
---|
1554 | definition frame_bound_on_steps_to_cost1 : frame → nat → Prop ≝ |
---|
1555 | λf. bound_on_steps_to_cost1 (f_graph (func f)) (next f). |
---|
1556 | |
---|
1557 | inductive state_bound_on_steps_to_cost : state → nat → Prop ≝ |
---|
1558 | | sbostc_state : ∀f,fs,m,n. frame_bound_on_steps_to_cost1 f n → state_bound_on_steps_to_cost (State f fs m) n |
---|
1559 | | sbostc_call : ∀fd,args,dst,f,fs,m,n. frame_bound_on_steps_to_cost f n → state_bound_on_steps_to_cost (Callstate fd args dst (f::fs) m) (S n) |
---|
1560 | | sbostc_ret : ∀rtv,dst,f,fs,m,n. frame_bound_on_steps_to_cost f n → state_bound_on_steps_to_cost (Returnstate rtv dst (f::fs) m) (S n) |
---|
1561 | . |
---|
1562 | |
---|
1563 | lemma state_bound_on_steps_to_cost_zero : ∀s. |
---|
1564 | ¬ state_bound_on_steps_to_cost s O. |
---|
1565 | #s % #H inversion H |
---|
1566 | [ #H46 #H47 #H48 #H49 #H50 #H51 #H52 #H53 destruct |
---|
1567 | whd in H50; @(bound_on_steps_to_cost1_inv_ind … H50) (* XXX inversion H50*) |
---|
1568 | #H55 #H56 #H57 #H58 #H59 #H60 #H61 normalize in H60; destruct |
---|
1569 | | #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 destruct |
---|
1570 | | #H13 #H14 #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 destruct |
---|
1571 | ] qed. |
---|
1572 | |
---|
1573 | lemma eval_steps : ∀ge,f,fs,m,tr,s'. |
---|
1574 | eval_statement ge (State f fs m) = Value ??? 〈tr,s'〉 → |
---|
1575 | steps_for_statement (lookup_present ?? (f_graph (func f)) (next f) (next_ok f)) = |
---|
1576 | match s' with [ State _ _ _ ⇒ 1 | Callstate _ _ _ _ _ ⇒ 2 | Returnstate _ _ _ _ ⇒ 2 | Finalstate _ ⇒ 1 ]. |
---|
1577 | #ge * #func #locals #next #next_ok #sp #dst #fs #m #tr #s' |
---|
1578 | whd in ⊢ (??%? → ?); |
---|
1579 | generalize in ⊢ (??(?%)? → ?); cases (lookup_present ??? next next_ok) |
---|
1580 | [ #l #LP whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1581 | | #cl #l #LP whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1582 | | #ty #r #c #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev @bind_ok #locals' #El whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1583 | | #ty #ty' #op #r1 #r2 #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev @bind_ok #v' #Ev' @bind_ok #locals' #El whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1584 | | #ty1 #ty2 #ty' #op #r1 #r2 #r3 #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v1 #Ev1 @bind_ok #v2 #Ev2 @bind_ok #v' #Ev' @bind_ok #locals' #El whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1585 | | #ch #r1 #r2 #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v1 #Ev1 @bind_ok #v2 #Ev2 @bind_ok #locals' #El whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1586 | | #ch #r1 #r2 #l #LP whd in ⊢ (??%? → ?); @bind_res_value #v1 #Ev1 @bind_ok #v2 #Ev2 @bind_ok #m' #Em whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1587 | | #id #rs #r #l #LP whd in ⊢ (??%? → ?); @bind_res_value #b #Eb @bind_ok #fd #Efd @bind_ok #vs #Evs whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1588 | | #r #rs #r' #l #LP whd in ⊢ (??%? → ?); @bind_res_value #fv #Efv @bind_ok #fd #Efd @bind_ok #vs #Evs whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1589 | | #r #l1 #l2 #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev @bind_ok #b #Eb whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1590 | | #r #ls #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev |
---|
1591 | cases v [ #E normalize in E; destruct | #sz #i | #f #E normalize in E; destruct | #E normalize in E; destruct | #p #E normalize in E; destruct ] |
---|
1592 | whd in ⊢ (??%? → ?); |
---|
1593 | generalize in ⊢ (??(?%)? → ?); |
---|
1594 | cases (nth_opt label (nat_of_bitvector (bitsize_of_intsize sz) i) ls) in ⊢ (???% → ??(match % with [ _ ⇒ ? | _ ⇒ ? ] ?)? → ?); |
---|
1595 | [ #e #E normalize in E; destruct |
---|
1596 | | #l #El whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1597 | ] |
---|
1598 | | #LP whd in ⊢ (??%? → ?); @bind_res_value #v #Ev whd in ⊢ (??%? → ?); #E destruct @refl |
---|
1599 | ] qed. |
---|
1600 | |
---|
1601 | lemma bound_after_call : ∀ge.∀s,s':RTLabs_state ge.∀n. |
---|
1602 | state_bound_on_steps_to_cost s (S n) → |
---|
1603 | ∀CL:RTLabs_classify s = cl_call. |
---|
1604 | as_after_return (RTLabs_status ge) «s, CL» s' → |
---|
1605 | RTLabs_cost s' = false → |
---|
1606 | state_bound_on_steps_to_cost s' n. |
---|
1607 | #ge * #s #stk #mtc * #s' #stk' #mtc' #n #H #CL whd in ⊢ (% → ?); -stk -stk' lapply CL -CL inversion H |
---|
1608 | [ #f #fs #m #n' #S #E1 #E2 #_ #CL @⊥ cases (rtlabs_call_inv … CL) |
---|
1609 | #fn * #args * #dst * #stk * #m' #E destruct |
---|
1610 | | #fd #args #dst #f #fs #m #n' #S #E1 #E2 #_ destruct |
---|
1611 | whd in S; #CL cases s' |
---|
1612 | [ #f' #fs' #m' * #N #F #CS |
---|
1613 | %1 whd |
---|
1614 | inversion S |
---|
1615 | [ #l #n #P #CS' #E1 #E2 #_ destruct @⊥ |
---|
1616 | change with (is_cost_label ?) in CS:(??%?); >N in P CS'; >F >CS #P * |
---|
1617 | | #l #n #B #E1 #E2 #_ destruct <N <F @B |
---|
1618 | ] |
---|
1619 | | #fd' #args' #dst' #fs' #m' * |
---|
1620 | | #rv #dst' #fs' #m' * |
---|
1621 | | #r #E normalize in E; destruct |
---|
1622 | ] |
---|
1623 | | #rtv #dst #f #fs #m #n' #S #E1 #E2 #E3 destruct #CL normalize in CL; destruct |
---|
1624 | ] qed. |
---|
1625 | |
---|
1626 | lemma bound_after_step : ∀ge,s,tr,s',n. |
---|
1627 | state_bound_on_steps_to_cost s (S n) → |
---|
1628 | eval_statement ge s = Value ??? 〈tr, s'〉 → |
---|
1629 | RTLabs_cost s' = false → |
---|
1630 | (RTLabs_classify s' = cl_return ∨ RTLabs_classify s = cl_call) ∨ |
---|
1631 | state_bound_on_steps_to_cost s' n. |
---|
1632 | #ge #s #tr #s' #n #BOUND1 inversion BOUND1 |
---|
1633 | [ #f #fs #m #m #FS #E1 #E2 #_ destruct |
---|
1634 | #EVAL cases (eval_successor … EVAL) |
---|
1635 | [ /3/ |
---|
1636 | | * #l * #S1 #S2 #NC %2 |
---|
1637 | (* |
---|
1638 | cases (bound_on_steps_to_cost1_inv … FS ?) [2: @(next_ok f) ] |
---|
1639 | *) |
---|
1640 | @(bound_on_steps_to_cost1_inv_ind … FS) #next #n' #next_ok #IH #E1 #E2 #E3 destruct |
---|
1641 | inversion (eval_preserves … EVAL) |
---|
1642 | [ #ge0 #f0 #f' #fs' #m0 #m' #F #E4 #E5 #E6 #_ destruct |
---|
1643 | >(eval_steps … EVAL) in E2; #En normalize in En; |
---|
1644 | inversion F #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 destruct |
---|
1645 | %1 inversion (IH … S2) |
---|
1646 | [ #lx #nx #LPx #CSx #E1x #E2x @⊥ destruct |
---|
1647 | change with (RTLabs_cost (State (mk_frame H1 H7 lx LPx H5 H6) fs' m')) in CSx:(?%); |
---|
1648 | whd in S1:(??%?); destruct >NC in CSx; * |
---|
1649 | | whd in S1:(??%?); destruct #H71 #H72 #H73 #H74 #H75 #H76 destruct @H73 |
---|
1650 | ] |
---|
1651 | | #ge0 #f0 #fs' #m0 #fd #args #f' #dst #F #b #FFP #E4 #E5 #E6 #_ destruct |
---|
1652 | >(eval_steps … EVAL) in E2; #En normalize in En; |
---|
1653 | inversion F #H1 #H2 #H3 #H4 #H5 #H6 #H7 #H8 #H9 #H10 #H11 #H12 destruct |
---|
1654 | %2 @IH normalize in S1; destruct @S2 |
---|
1655 | | #H14 #H15 #H16 #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 #H28 |
---|
1656 | destruct |
---|
1657 | | #H31 #H32 #H33 #H34 #H35 #H36 #H37 #H38 #H39 #H40 #H41 destruct |
---|
1658 | normalize in S1; destruct |
---|
1659 | | #H44 #H45 #H46 #H47 #H48 #H49 #H50 #H51 #H52 #H53 #H54 #H55 destruct |
---|
1660 | | #H267 #H268 #H269 #H270 #H271 #H272 #H273 #H274 destruct |
---|
1661 | ] |
---|
1662 | ] |
---|
1663 | | #H58 #H59 #H60 #H61 #H62 #H63 #H64 #H65 #H66 #H67 #H68 #H69 #H70 destruct |
---|
1664 | /3/ |
---|
1665 | | #rtv #dst #f #fs #m #n' #FS #E1 #E2 #_ destruct |
---|
1666 | #EVAL #NC %2 inversion (eval_preserves … EVAL) |
---|
1667 | [ #H72 #H73 #H74 #H75 #H76 #H77 #H78 #H79 #H80 #H81 #H82 destruct |
---|
1668 | | #H84 #H85 #H86 #H87 #H88 #H89 #H90 #H91 #H92 #H93 #H94 #H95 #H96 #H97 #H98 destruct |
---|
1669 | | #H100 #H101 #H102 #H103 #H104 #H105 #H106 #H107 #H108 #H109 #H110 #H111 #H112 #H113 #H114 destruct |
---|
1670 | | #H116 #H117 #H118 #H119 #H120 #H121 #H122 #H123 #H124 #H125 #H126 destruct |
---|
1671 | | #ge' #f' #fs' #rtv' #dst' #f'' #m' #F #E1 #E2 #E3 #_ destruct |
---|
1672 | %1 whd in FS ⊢ %; |
---|
1673 | inversion (stack_preserved_return … EVAL) [ @refl | 2,4,5: #H141 #H142 #H143 #H144 #H145 #H146 #H147 try #H148 try #H149 destruct ] |
---|
1674 | #s1 #f1 #f2 #fs #m #FE #FR #SS1 #_ #E1 #E2 #_ destruct <FE |
---|
1675 | inversion SS1 [ #H163 #H164 #H165 #H166 #H167 #H168 destruct | #H170 #H171 #H172 #H173 #H174 #H175 #H176 #H177 #H178 destruct | #rtv #dst #fs0 #m0 #E1 #E2 #_ destruct ] |
---|
1676 | inversion F #func #locals #next #next_ok #sp #retdst #locals' #next' #next_ok' #E1 #E2 #_ destruct |
---|
1677 | inversion FS |
---|
1678 | [ #lx #nx #LPx #CSx #E1x #E2x @⊥ destruct |
---|
1679 | change with (RTLabs_cost (State (mk_frame func locals' lx ? sp retdst) fs m0)) in CSx:(?%); |
---|
1680 | >NC in CSx; * |
---|
1681 | | #lx #nx #H #E1x #E2x #_ destruct @H |
---|
1682 | ] |
---|
1683 | | #H284 #H285 #H286 #H287 #H288 #H289 #H290 #H291 destruct |
---|
1684 | ] |
---|
1685 | ] qed. |
---|
1686 | |
---|
1687 | |
---|
1688 | |
---|
1689 | |
---|
1690 | definition soundly_labelled_fn : internal_function → Prop ≝ |
---|
1691 | λf. ∀l. present … (f_graph f) l → ∃n. bound_on_steps_to_cost1 (f_graph f) l n. |
---|
1692 | |
---|
1693 | definition soundly_labelled_ge : genv → Prop ≝ |
---|
1694 | λge. ∀b,f. find_funct_ptr … ge b = Some ? (Internal ? f) → soundly_labelled_fn f. |
---|
1695 | |
---|
1696 | definition soundly_labelled_state : state → Prop ≝ |
---|
1697 | λs. match s with |
---|
1698 | [ State f fs m ⇒ soundly_labelled_fn (func f) ∧ All ? (λf. soundly_labelled_fn (func f)) fs |
---|
1699 | | Callstate fd _ _ fs _ ⇒ match fd with [ Internal fn ⇒ soundly_labelled_fn fn | External _ ⇒ True ] ∧ |
---|
1700 | All ? (λf. soundly_labelled_fn (func f)) fs |
---|
1701 | | Returnstate _ _ fs _ ⇒ All ? (λf. soundly_labelled_fn (func f)) fs |
---|
1702 | | Finalstate _ ⇒ True |
---|
1703 | ]. |
---|
1704 | |
---|
1705 | lemma steps_from_sound : ∀s. |
---|
1706 | RTLabs_cost s = true → |
---|
1707 | soundly_labelled_state s → |
---|
1708 | ∃n. state_bound_on_steps_to_cost s n. |
---|
1709 | * [ #f #fs #m #CS | #a #b #c #d #e #E normalize in E; destruct | #a #b #c #d #E normalize in E; destruct | #a #E normalize in E; destruct ] |
---|
1710 | whd in ⊢ (% → ?); * #SLF #_ |
---|
1711 | cases (SLF (next f) (next_ok f)) #n #B1 |
---|
1712 | %{n} % @B1 |
---|
1713 | qed. |
---|
1714 | |
---|
1715 | lemma soundly_labelled_state_step : ∀ge,s,tr,s'. |
---|
1716 | soundly_labelled_ge ge → |
---|
1717 | eval_statement ge s = Value ??? 〈tr,s'〉 → |
---|
1718 | soundly_labelled_state s → |
---|
1719 | soundly_labelled_state s'. |
---|
1720 | #ge #s #tr #s' #ENV #EV #S |
---|
1721 | inversion (eval_preserves … EV) |
---|
1722 | [ #ge' #f #f' #fs #m #m' #F #E1 #E2 #E3 #_ destruct |
---|
1723 | whd in S ⊢ %; inversion F #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 #H28 destruct @S |
---|
1724 | | #ge' #f #fs #m #fd #args #f' #dst #F #b #FFP #E1 #E2 #E3 #_ destruct |
---|
1725 | whd in S ⊢ %; % |
---|
1726 | [ cases fd in FFP ⊢ %; // #fn #FFP @ENV // |
---|
1727 | | inversion F #H30 #H31 #H32 #H33 #H34 #H35 #H36 #H37 #H38 #H39 #H40 #H41 destruct @S |
---|
1728 | ] |
---|
1729 | | #ge' #fn #locals #next #nok #sp #fs #m #args #dst #m' #E1 #E2 #E3 #E4 destruct |
---|
1730 | whd in S ⊢ %; @S |
---|
1731 | | #ge' #f #fs #m #rtv #dst #m' #E1 #E2 #E3 #E4 destruct |
---|
1732 | whd in S ⊢ %; cases S // |
---|
1733 | | #ge' #f #fs #rtv #dst #f' #m #F #E1 #E2 #E3 #E4 destruct |
---|
1734 | whd in S ⊢ %; inversion F #H17 #H18 #H19 #H20 #H21 #H22 #H23 #H24 #H25 #H26 #H27 #H28 destruct @S |
---|
1735 | | #ge' #r #dst #m #E1 #E2 #E3 #E4 destruct @I |
---|
1736 | ] qed. |
---|
1737 | |
---|
1738 | lemma soundly_labelled_state_preserved : ∀s,s'. |
---|
1739 | stack_preserved ends_with_ret s s' → |
---|
1740 | soundly_labelled_state s → |
---|
1741 | soundly_labelled_state s'. |
---|
1742 | #s0 #s0' #SP inversion SP |
---|
1743 | [ #H73 #H74 #H75 #H76 #H77 #H78 #H79 #H80 #H81 #H82 destruct |
---|
1744 | | #s1 #f #f' #fs #m #N #F #S1 #E1 #E2 #E3 #E4 destruct |
---|
1745 | inversion S1 |
---|
1746 | [ #f1 #fs1 #m1 #E1 #E2 #E3 destruct |
---|
1747 | * #_ #S whd in S; |
---|
1748 | inversion F #H96 #H97 #H98 #H99 #H100 #H101 #H102 #H103 #H104 #H105 #H106 #H107 |
---|
1749 | destruct @S |
---|
1750 | | #fd #args #dst #f1 #fs1 #m1 #E1 #E2 #E3 destruct * #_ * #_ #S |
---|
1751 | inversion F #H96 #H97 #H98 #H99 #H100 #H101 #H102 #H103 #H104 #H105 #H106 #H107 |
---|
1752 | destruct @S |
---|
1753 | | #rtv #dst #fs1 #m1 #E1 #E2 #E3 destruct #S |
---|
1754 | inversion F #H96 #H97 #H98 #H99 #H100 #H101 #H102 #H103 #H104 #H105 #H106 #H107 |
---|
1755 | destruct @S |
---|
1756 | ] |
---|
1757 | | // |
---|
1758 | | // |
---|
1759 | ] qed. |
---|
1760 | |
---|
1761 | (* When constructing an infinite trace, we need to be able to grab the finite |
---|
1762 | portion of the trace for the next [trace_label_diverges] constructor. We |
---|
1763 | use the fact that the trace is soundly labelled to achieve this. *) |
---|
1764 | |
---|
1765 | record remainder_ok (ge:genv) (s:RTLabs_state ge) (t:flat_trace io_out io_in ge s) : Type[0] ≝ { |
---|
1766 | ro_well_cost_labelled: well_cost_labelled_state s; |
---|
1767 | ro_soundly_labelled: soundly_labelled_state s; |
---|
1768 | ro_no_termination: Not (∃depth. inhabited (will_return ge depth s t)); |
---|
1769 | ro_not_undefined: not_wrong … t; |
---|
1770 | ro_not_final: RTLabs_is_final s = None ? |
---|
1771 | }. |
---|
1772 | |
---|
1773 | inductive finite_prefix (ge:genv) : RTLabs_state ge → Prop ≝ |
---|
1774 | | fp_tal : ∀s,s':RTLabs_state ge. |
---|
1775 | trace_any_label (RTLabs_status ge) doesnt_end_with_ret s s' → |
---|
1776 | ∀t:flat_trace io_out io_in ge s'. |
---|
1777 | remainder_ok ge s' t → |
---|
1778 | finite_prefix ge s |
---|
1779 | | fp_tac : ∀s1,s2,s3:RTLabs_state ge. |
---|
1780 | trace_any_call (RTLabs_status ge) s1 s2 → |
---|
1781 | well_cost_labelled_state s2 → |
---|
1782 | as_execute (RTLabs_status ge) s2 s3 → |
---|
1783 | ∀t:flat_trace io_out io_in ge s3. |
---|
1784 | remainder_ok ge s3 t → |
---|
1785 | finite_prefix ge s1 |
---|
1786 | . |
---|
1787 | |
---|
1788 | definition fp_add_default : ∀ge. ∀s,s':RTLabs_state ge. |
---|
1789 | RTLabs_classify s = cl_other → |
---|
1790 | finite_prefix ge s' → |
---|
1791 | as_execute (RTLabs_status ge) s s' → |
---|
1792 | RTLabs_cost s' = false → |
---|
1793 | finite_prefix ge s ≝ |
---|
1794 | λge,s,s',OTHER,fp. |
---|
1795 | match fp return λs1.λfp1:finite_prefix ge s1. as_execute (RTLabs_status ge) ? s1 → RTLabs_cost s1 = false → finite_prefix ge s with |
---|
1796 | [ fp_tal s' sf TAL rem rok ⇒ λEVAL, NOT_COST. fp_tal ge s sf |
---|
1797 | (tal_step_default (RTLabs_status ge) doesnt_end_with_ret s s' sf EVAL TAL OTHER (RTLabs_not_cost … NOT_COST)) |
---|
1798 | rem rok |
---|
1799 | | fp_tac s1 s2 s3 TAC WCL2 EV rem rok ⇒ λEVAL, NOT_COST. fp_tac ge s s2 s3 |
---|
1800 | (tac_step_default (RTLabs_status ge) ??? EVAL TAC OTHER (RTLabs_not_cost … NOT_COST)) |
---|
1801 | WCL2 EV rem rok |
---|
1802 | ]. |
---|
1803 | |
---|
1804 | definition fp_add_terminating_call : ∀ge.∀s,s1,s'':RTLabs_state ge. |
---|
1805 | as_execute (RTLabs_status ge) s s1 → |
---|
1806 | ∀CALL:RTLabs_classify s = cl_call. |
---|
1807 | finite_prefix ge s'' → |
---|
1808 | trace_label_return (RTLabs_status ge) s1 s'' → |
---|
1809 | as_after_return (RTLabs_status ge) (mk_Sig ?? s CALL) s'' → |
---|
1810 | RTLabs_cost s'' = false → |
---|
1811 | finite_prefix ge s ≝ |
---|
1812 | λge,s,s1,s'',EVAL,CALL,fp. |
---|
1813 | match fp return λs''.λfp:finite_prefix ge s''. trace_label_return (RTLabs_status ge) ? s'' → as_after_return (RTLabs_status ge) ? s'' → RTLabs_cost s'' = false → finite_prefix ge s with |
---|
1814 | [ fp_tal s'' sf TAL rem rok ⇒ λTLR,RET,NOT_COST. fp_tal ge s sf |
---|
1815 | (tal_step_call (RTLabs_status ge) doesnt_end_with_ret s s1 s'' sf EVAL CALL RET TLR (RTLabs_not_cost … NOT_COST) TAL) |
---|
1816 | rem rok |
---|
1817 | | fp_tac s'' s2 s3 TAC WCL2 EV rem rok ⇒ λTLR,RET,NOT_COST. fp_tac ge s s2 s3 |
---|
1818 | (tac_step_call (RTLabs_status ge) s s'' s2 s1 EVAL CALL RET TLR (RTLabs_not_cost … NOT_COST) TAC) |
---|
1819 | WCL2 EV rem rok |
---|
1820 | ]. |
---|
1821 | |
---|
1822 | lemma not_return_to_not_final : ∀ge,s,tr,s'. |
---|
1823 | eval_statement ge s = Value ??? 〈tr, s'〉 → |
---|
1824 | RTLabs_classify s ≠ cl_return → |
---|
1825 | RTLabs_is_final s' = None ?. |
---|
1826 | #ge #s #tr #s' #EV |
---|
1827 | inversion (eval_preserves … EV) // |
---|
1828 | #H48 #H49 #H50 #H51 #H52 #H53 #H54 #H55 #CL |
---|
1829 | @⊥ @(absurd ?? CL) @refl |
---|
1830 | qed. |
---|
1831 | |
---|
1832 | definition termination_oracle ≝ ∀ge,depth,s,trace. |
---|
1833 | inhabited (will_return ge depth s trace) ∨ ¬ inhabited (will_return ge depth s trace). |
---|
1834 | |
---|
1835 | let rec finite_segment ge (s:RTLabs_state ge) n trace |
---|
1836 | (ORACLE: termination_oracle) |
---|
1837 | (TRACE_OK: remainder_ok ge s trace) |
---|
1838 | (ENV_COSTLABELLED: well_cost_labelled_ge ge) |
---|
1839 | (ENV_SOUNDLY_LABELLED: soundly_labelled_ge ge) |
---|
1840 | (LABEL_LIMIT: state_bound_on_steps_to_cost s n) |
---|
1841 | on n : finite_prefix ge s ≝ |
---|
1842 | match n return λn. state_bound_on_steps_to_cost s n → finite_prefix ge s with |
---|
1843 | [ O ⇒ λLABEL_LIMIT. ⊥ |
---|
1844 | | S n' ⇒ |
---|
1845 | match s return λs:RTLabs_state ge. ∀trace:flat_trace io_out io_in ge s. remainder_ok ge s trace → state_bound_on_steps_to_cost s (S n') → finite_prefix ge s with [ mk_RTLabs_state s0 stk mtc0 ⇒ λtrace'. |
---|
1846 | match trace' return λs:state.λtrace:flat_trace io_out io_in ge s. ∀mtc:Ras_Fn_Match ge s stk. remainder_ok ge (mk_RTLabs_state ge s ? mtc) trace → state_bound_on_steps_to_cost s (S n') → finite_prefix ge (mk_RTLabs_state ge s ? mtc) with |
---|
1847 | [ ft_stop st FINAL ⇒ λmtc,TRACE_OK,LABEL_LIMIT. ⊥ |
---|
1848 | | ft_step start tr next EV trace' ⇒ λmtc,TRACE_OK,LABEL_LIMIT. |
---|
1849 | let start' ≝ mk_RTLabs_state ge start stk mtc in |
---|
1850 | let next' ≝ next_state ge start' next tr EV in |
---|
1851 | match RTLabs_classify start return λx. RTLabs_classify start = x → ? with |
---|
1852 | [ cl_other ⇒ λCL. |
---|
1853 | let TRACE_OK' ≝ ? in |
---|
1854 | match RTLabs_cost next return λx. RTLabs_cost next = x → ? with |
---|
1855 | [ true ⇒ λCS. |
---|
1856 | fp_tal ge start' next' (tal_base_not_return (RTLabs_status ge) start' next' ?? ((proj1 … (RTLabs_costed ge next')) … CS)) trace' TRACE_OK' |
---|
1857 | | false ⇒ λCS. |
---|
1858 | let fs ≝ finite_segment ge next' n' trace' ORACLE TRACE_OK' ENV_COSTLABELLED ENV_SOUNDLY_LABELLED ? in |
---|
1859 | fp_add_default ge start' next' CL fs ? CS |
---|
1860 | ] (refl ??) |
---|
1861 | | cl_jump ⇒ λCL. |
---|
1862 | fp_tal ge start' next' (tal_base_not_return (RTLabs_status ge) start' next' ?? ?) trace' ? |
---|
1863 | | cl_call ⇒ λCL. |
---|
1864 | match ORACLE ge O next trace' return λ_. finite_prefix ge start' with |
---|
1865 | [ or_introl TERMINATES ⇒ |
---|
1866 | match TERMINATES with [ witness TERMINATES ⇒ |
---|
1867 | let tlr ≝ make_label_return' ge O next' trace' ENV_COSTLABELLED ?? TERMINATES in |
---|
1868 | let TRACE_OK' ≝ ? in |
---|
1869 | match RTLabs_cost (new_state … tlr) return λx. RTLabs_cost (new_state … tlr) = x → finite_prefix ge start' with |
---|
1870 | [ true ⇒ λCS. fp_tal ge start' (new_state … tlr) (tal_base_call (RTLabs_status ge) start' next' (new_state … tlr) ? CL ? (new_trace … tlr) ((proj1 … (RTLabs_costed ge ?)) … CS)) (remainder … tlr) TRACE_OK' |
---|
1871 | | false ⇒ λCS. |
---|
1872 | let fs ≝ finite_segment ge (new_state … tlr) n' (remainder … tlr) ORACLE TRACE_OK' ENV_COSTLABELLED ENV_SOUNDLY_LABELLED ? in |
---|
1873 | fp_add_terminating_call … fs (new_trace … tlr) ? CS |
---|
1874 | ] (refl ??) |
---|
1875 | ] |
---|
1876 | | or_intror NO_TERMINATION ⇒ |
---|
1877 | fp_tac ge start' start' next' (tac_base (RTLabs_status ge) start' CL) ?? trace' ? |
---|
1878 | ] |
---|
1879 | | cl_return ⇒ λCL. ⊥ |
---|
1880 | ] (refl ??) |
---|
1881 | | ft_wrong start m NF EV ⇒ λmtc,TRACE_OK,LABEL_LIMIT. ⊥ |
---|
1882 | ] mtc0 |
---|
1883 | ] trace TRACE_OK |
---|
1884 | ] LABEL_LIMIT. |
---|
1885 | [ cases (state_bound_on_steps_to_cost_zero s) /2/ |
---|
1886 | | @(absurd … (ro_not_final … TRACE_OK) FINAL) |
---|
1887 | | @(absurd ?? (ro_no_termination … TRACE_OK)) |
---|
1888 | %{0} % @wr_base // |
---|
1889 | | @(proj1 … (RTLabs_costed …)) @(well_cost_labelled_jump … EV) [ @(ro_well_cost_labelled … TRACE_OK) | // ] |
---|
1890 | | 5,6,9,10,11: /3/ |
---|
1891 | | cases TRACE_OK #H1 #H2 #H3 #H4 #H5 |
---|
1892 | % [ @(well_cost_labelled_state_step … EV) // |
---|
1893 | | @(soundly_labelled_state_step … EV) // |
---|
1894 | | @(not_to_not … (ro_no_termination … TRACE_OK)) * #depth * #TM1 %{depth} % @wr_step /2/ |
---|
1895 | | @(still_not_wrong … EV) // |
---|
1896 | | @(not_return_to_not_final … EV) >CL % #E destruct |
---|
1897 | ] |
---|
1898 | | @(RTLabs_after_call ge start' next' … EV (stack_ok … tlr)) |
---|
1899 | | @(RTLabs_after_call ge start' next' … EV (stack_ok … tlr)) |
---|
1900 | | @(bound_after_call ge start' (new_state … tlr) ? LABEL_LIMIT CL ? CS) |
---|
1901 | @(RTLabs_after_call ge start' next' … EV (stack_ok … tlr)) |
---|
1902 | | % [ /2/ |
---|
1903 | | @(soundly_labelled_state_preserved … (stack_ok … tlr)) |
---|
1904 | @(soundly_labelled_state_step … EV) /2/ @(ro_soundly_labelled … TRACE_OK) |
---|
1905 | | @(not_to_not … (ro_no_termination … TRACE_OK)) * #depth * #TM1 %{depth} % |
---|
1906 | @wr_call // |
---|
1907 | @(will_return_prepend … TERMINATES … TM1) |
---|
1908 | cases (terminates … tlr) // |
---|
1909 | | @(will_return_not_wrong … TERMINATES) |
---|
1910 | [ @(still_not_wrong … EV) @(ro_not_undefined … TRACE_OK) |
---|
1911 | | cases (terminates … tlr) // |
---|
1912 | ] |
---|
1913 | | (* By stack preservation we cannot be in the final state *) |
---|
1914 | inversion (stack_ok … tlr) |
---|
1915 | [ #H101 #H102 #H103 #H104 #H105 #H106 #H107 #H108 #H109 destruct |
---|
1916 | | #s1 #f #f' #fs #m #N #F #S #E1 #E2 #E3 #E4 -TERMINATES destruct @refl |
---|
1917 | | #s1 #r #S #E1 #E2 #E3 #E4 -TERMINATES destruct whd in S:(??%); -next' -s0 |
---|
1918 | cases (rtlabs_call_inv … CL) #fd * #args * #dst * #stk * #m #E destruct |
---|
1919 | inversion (eval_preserves … EV) |
---|
1920 | [ 1,2,4,5,6: #H111 #H112 #H113 #H114 #H115 #H116 #H117 #H118 try #H119 try #H120 try #H121 try #H122 try #H123 @⊥ -next destruct ] |
---|
1921 | #ge' #fn #locals #nextx #nok #sp #fs #m' #args' #dst' #m'' #E1 #E2 #E3 #E4 -TRACE_OK destruct |
---|
1922 | inversion S |
---|
1923 | [ #f #fs0 #m #E1 #E2 #E3 destruct | *: #H123 #H124 #H125 #H126 #H127 #H128 #H129 try #H130 destruct ] |
---|
1924 | (* state_bound_on_steps_to_cost needs to know about the current stack frame, |
---|
1925 | so we can use it as a witness that at least one frame exists *) |
---|
1926 | inversion LABEL_LIMIT |
---|
1927 | #H141 #H142 #H143 #H144 #H145 #H146 #H147 #H148 try #H150 destruct |
---|
1928 | | #H173 #H174 #H175 #H176 #H177 #H178 #H179 #H180 #H181 destruct |
---|
1929 | ] |
---|
1930 | ] |
---|
1931 | | @(well_cost_labelled_state_step … EV) /2/ @(ro_well_cost_labelled … TRACE_OK) |
---|
1932 | | @(well_cost_labelled_call … EV) [ @(ro_well_cost_labelled … TRACE_OK) | // ] |
---|
1933 | | /2/ |
---|
1934 | | %{tr} %{EV} % |
---|
1935 | | cases TRACE_OK #H1 #H2 #H3 #H4 #H5 |
---|
1936 | % [ @(well_cost_labelled_state_step … EV) /2/ |
---|
1937 | | @(soundly_labelled_state_step … EV) /2/ |
---|
1938 | | @(not_to_not … NO_TERMINATION) * #depth * #TM % |
---|
1939 | @(will_return_lower … TM) // |
---|
1940 | | @(still_not_wrong … EV) /2/ |
---|
1941 | | @(not_return_to_not_final … EV) >CL % #E destruct |
---|
1942 | ] |
---|
1943 | | %2 @CL |
---|
1944 | | 21,22: %{tr} %{EV} % |
---|
1945 | | cases (bound_after_step … LABEL_LIMIT EV ?) |
---|
1946 | [ * [ #TERMINATES @⊥ @(absurd ?? (ro_no_termination … TRACE_OK)) %{0} % @wr_step [ %1 // | |
---|
1947 | inversion trace' |
---|
1948 | [ #s0 #FINAL #E1 #E2 -TRACE_OK' destruct @⊥ |
---|
1949 | @(absurd ?? FINAL) @(not_return_to_not_final … EV) |
---|
1950 | % >CL #E destruct |
---|
1951 | | #s1 #tr1 #s2 #EVAL' #trace'' #E1 #E2 -TRACE_OK' destruct |
---|
1952 | @wr_base // |
---|
1953 | | #H99 #H100 #H101 #H102 #H103 -TRACE_OK' destruct |
---|
1954 | inversion (ro_not_undefined … TRACE_OK) |
---|
1955 | [ #H137 #H138 #H139 #H140 #H141 destruct |
---|
1956 | | #H143 #H144 #H145 #H146 #H147 #H148 #H149 #H150 #H151 #H152 destruct |
---|
1957 | inversion H148 |
---|
1958 | [ #H153 #H154 #H155 #H156 #H157 destruct |
---|
1959 | | #H159 #H160 #H161 #H162 #H163 #H164 #H165 #H166 #H167 destruct |
---|
1960 | ] |
---|
1961 | ] |
---|
1962 | ] |
---|
1963 | ] |
---|
1964 | | >CL #E destruct |
---|
1965 | ] |
---|
1966 | | // |
---|
1967 | | // |
---|
1968 | ] |
---|
1969 | | cases TRACE_OK #H1 #H2 #H3 #H4 #H5 |
---|
1970 | % [ @(well_cost_labelled_state_step … EV) // |
---|
1971 | | @(soundly_labelled_state_step … EV) // |
---|
1972 | | @(not_to_not … (ro_no_termination … TRACE_OK)) |
---|
1973 | * #depth * #TERM %{depth} % @wr_step /2/ |
---|
1974 | | @(still_not_wrong … (ro_not_undefined … TRACE_OK)) |
---|
1975 | | @(not_return_to_not_final … EV) >CL % #E destruct |
---|
1976 | ] |
---|
1977 | | inversion (ro_not_undefined … TRACE_OK) |
---|
1978 | [ #H169 #H170 #H171 #H172 #H173 destruct |
---|
1979 | | #H175 #H176 #H177 #H178 #H179 #H180 #H181 #H182 #H183 destruct |
---|
1980 | ] |
---|
1981 | ] qed. |
---|
1982 | |
---|
1983 | (* NB: This isn't quite what I'd like. Ideally, we'd show the existence of |
---|
1984 | a trace_label_diverges value, but I only know how to construct those |
---|
1985 | using a cofixpoint in Type[0], which means I can't use the termination |
---|
1986 | oracle. |
---|
1987 | *) |
---|
1988 | |
---|
1989 | let corec make_label_diverges ge (s:RTLabs_state ge) |
---|
1990 | (trace: flat_trace io_out io_in ge s) |
---|
1991 | (ORACLE: termination_oracle) |
---|
1992 | (TRACE_OK: remainder_ok ge s trace) |
---|
1993 | (ENV_COSTLABELLED: well_cost_labelled_ge ge) |
---|
1994 | (ENV_SOUNDLY_LABELLED: soundly_labelled_ge ge) |
---|
1995 | (STATEMENT_COSTLABEL: RTLabs_cost s = true) (* current statement is a cost label *) |
---|
1996 | : trace_label_diverges_exists (RTLabs_status ge) s ≝ |
---|
1997 | match steps_from_sound s STATEMENT_COSTLABEL (ro_soundly_labelled … TRACE_OK) with |
---|
1998 | [ ex_intro n B ⇒ |
---|
1999 | match finite_segment ge s n trace ORACLE TRACE_OK ENV_COSTLABELLED ENV_SOUNDLY_LABELLED B |
---|
2000 | return λs:RTLabs_state ge.λ_. RTLabs_cost s = true → trace_label_diverges_exists (RTLabs_status ge) s |
---|
2001 | with |
---|
2002 | [ fp_tal s s' T t tOK ⇒ λSTATEMENT_COSTLABEL. |
---|
2003 | let T' ≝ make_label_diverges ge s' t ORACLE tOK ENV_COSTLABELLED ENV_SOUNDLY_LABELLED ? in |
---|
2004 | tld_step' (RTLabs_status ge) s s' (tll_base … T ((proj1 … (RTLabs_costed …)) … STATEMENT_COSTLABEL)) T' |
---|
2005 | (* |
---|
2006 | match make_label_diverges ge s' t ORACLE tOK ENV_COSTLABELLED ENV_SOUNDLY_LABELLED ? with |
---|
2007 | [ ex_intro T' _ ⇒ |
---|
2008 | ex_intro ?? (tld_step (RTLabs_status ge) s s' (tll_base … T STATEMENT_COSTLABEL) T') I |
---|
2009 | ]*) |
---|
2010 | | fp_tac s s2 s3 T WCL2 EV t tOK ⇒ λSTATEMENT_COSTLABEL. |
---|
2011 | let T' ≝ make_label_diverges ge s3 t ORACLE tOK ENV_COSTLABELLED ENV_SOUNDLY_LABELLED ? in |
---|
2012 | tld_base' (RTLabs_status ge) s s2 s3 (tlc_base … T ((proj1 … (RTLabs_costed …)) … STATEMENT_COSTLABEL)) ?? T' |
---|
2013 | (* |
---|
2014 | match make_label_diverges ge s3 t ORACLE tOK ENV_COSTLABELLED ENV_SOUNDLY_LABELLED ? with |
---|
2015 | [ ex_intro T' _ ⇒ |
---|
2016 | ex_intro ?? (tld_base (RTLabs_status ge) s s2 s3 (tlc_base … T STATEMENT_COSTLABEL) ?? T') ? |
---|
2017 | ]*) |
---|
2018 | ] STATEMENT_COSTLABEL |
---|
2019 | ]. |
---|
2020 | [ @((proj2 … (RTLabs_costed …))) @(trace_any_label_label … T) |
---|
2021 | | @EV |
---|
2022 | | @(trace_any_call_call … T) |
---|
2023 | | cases EV #tr * #EV' #N @(well_cost_labelled_call … EV') // @(trace_any_call_call … T) |
---|
2024 | ] qed. |
---|
2025 | |
---|
2026 | lemma after_the_initial_call_is_the_final_state : ∀ge,p,s1,tr,s2,s'. |
---|
2027 | make_initial_state p = OK ? s1 → |
---|
2028 | eval_statement ge s1 = Value ??? 〈tr,s2〉 → |
---|
2029 | stack_preserved ends_with_ret s2 s' → |
---|
2030 | RTLabs_is_final s' ≠ None ?. |
---|
2031 | #ge #p #s1 #tr #s2 #s' whd in ⊢ (??%? → ?); |
---|
2032 | @bind_ok #m #_ |
---|
2033 | @bind_ok #b #_ |
---|
2034 | @bind_ok #f #_ |
---|
2035 | #E destruct |
---|
2036 | #EV #SP inversion (eval_preserves … EV) |
---|
2037 | [ 3: #ge' #fn #locals #next #nok #sp #fs #m1 #args #dst #m2 #E1 #E2 #E3 #_ destruct |
---|
2038 | inversion SP |
---|
2039 | [ 3: #s1 #r #S #_ #_ #_ #_ % #E whd in E:(??%?); destruct |
---|
2040 | | *: #H28 #H29 #H30 #H31 #H32 #H33 #H34 #H35 #H36 try #H38 try #H39 try #H40 destruct |
---|
2041 | inversion H35 #H61 #H62 #H63 #H64 #H65 #H66 try #H68 try #H69 try #H70 destruct |
---|
2042 | ] |
---|
2043 | | *: #H98 #H99 #H100 #H101 #H102 #H103 #H104 #H105 try #H106 try #H107 try #H108 try #H109 try #H110 destruct |
---|
2044 | ] qed. |
---|
2045 | |
---|
2046 | lemma initial_state_is_call : ∀p,s. |
---|
2047 | make_initial_state p = OK ? s → |
---|
2048 | RTLabs_classify s = cl_call. |
---|
2049 | #p #s whd in ⊢ (??%? → ?); |
---|
2050 | @bind_ok #m #_ |
---|
2051 | @bind_ok #b #_ |
---|
2052 | @bind_ok #f #_ |
---|
2053 | #E destruct |
---|
2054 | @refl |
---|
2055 | qed. |
---|
2056 | |
---|
2057 | let rec whole_structured_trace_exists ge p (s:RTLabs_state ge) |
---|
2058 | (ORACLE: termination_oracle) |
---|
2059 | (ENV_COSTLABELLED: well_cost_labelled_ge ge) |
---|
2060 | (ENV_SOUNDLY_LABELLED: soundly_labelled_ge ge) |
---|
2061 | : ∀trace: flat_trace io_out io_in ge s. |
---|
2062 | ∀INITIAL: make_initial_state p = OK state s. |
---|
2063 | ∀NOT_WRONG: not_wrong ??? s trace. |
---|
2064 | ∀STATE_COSTLABELLED: well_cost_labelled_state s. |
---|
2065 | ∀STATE_SOUNDLY_LABELLED: soundly_labelled_state s. |
---|
2066 | trace_whole_program_exists (RTLabs_status ge) s ≝ |
---|
2067 | match s return λs:RTLabs_state ge. ∀trace:flat_trace io_out io_in ge s. |
---|
2068 | make_initial_state p = OK ? s → |
---|
2069 | not_wrong ??? s trace → |
---|
2070 | well_cost_labelled_state s → |
---|
2071 | soundly_labelled_state s → |
---|
2072 | trace_whole_program_exists (RTLabs_status ge) s with |
---|
2073 | [ mk_RTLabs_state s0 stk mtc0 ⇒ λtrace. |
---|
2074 | match trace return λs,trace. ∀mtc:Ras_Fn_Match ge s stk. |
---|
2075 | make_initial_state p = OK state s → |
---|
2076 | not_wrong ??? s trace → |
---|
2077 | well_cost_labelled_state s → |
---|
2078 | soundly_labelled_state s → |
---|
2079 | trace_whole_program_exists (RTLabs_status ge) (mk_RTLabs_state ge s stk mtc) with |
---|
2080 | [ ft_step s tr next EV trace' ⇒ λmtc,INITIAL,NOT_WRONG,STATE_COSTLABELLED,STATE_SOUNDLY_LABELLED. |
---|
2081 | let IS_CALL ≝ initial_state_is_call … INITIAL in |
---|
2082 | let s' ≝ mk_RTLabs_state ge s stk mtc in |
---|
2083 | let next' ≝ next_state ge s' next tr EV in |
---|
2084 | match ORACLE ge O next trace' with |
---|
2085 | [ or_introl TERMINATES ⇒ |
---|
2086 | match TERMINATES with |
---|
2087 | [ witness TERMINATES ⇒ |
---|
2088 | let tlr ≝ make_label_return' ge O next' trace' ENV_COSTLABELLED ?? TERMINATES in |
---|
2089 | twp_terminating (RTLabs_status ge) s' next' (new_state … tlr) IS_CALL ? (new_trace … tlr) ? |
---|
2090 | ] |
---|
2091 | | or_intror NO_TERMINATION ⇒ |
---|
2092 | twp_diverges (RTLabs_status ge) s' next' IS_CALL ? |
---|
2093 | (make_label_diverges ge next' trace' ORACLE ? |
---|
2094 | ENV_COSTLABELLED ENV_SOUNDLY_LABELLED ?) |
---|
2095 | ] |
---|
2096 | | ft_stop st FINAL ⇒ λmtc,INITIAL,NOT_WRONG. ⊥ |
---|
2097 | | ft_wrong start m NF EV ⇒ λmtc,INITIAL,NOT_WRONG. ⊥ |
---|
2098 | ] mtc0 ]. |
---|
2099 | [ cases (rtlabs_call_inv … (initial_state_is_call … INITIAL)) #fn * #args * #dst * #stk * #m #E destruct |
---|
2100 | cases FINAL #E @E @refl |
---|
2101 | | %{tr} %{EV} % |
---|
2102 | | @(after_the_initial_call_is_the_final_state … INITIAL EV) |
---|
2103 | @(stack_ok … tlr) |
---|
2104 | | @(well_cost_labelled_state_step … EV) // |
---|
2105 | | @(well_cost_labelled_call … EV) // |
---|
2106 | | %{tr} %{EV} % |
---|
2107 | | @(well_cost_labelled_call … EV) // |
---|
2108 | | % [ @(well_cost_labelled_state_step … EV) // |
---|
2109 | | @(soundly_labelled_state_step … EV) // |
---|
2110 | | @(not_to_not … NO_TERMINATION) * #d * #TM % /2/ |
---|
2111 | | @(still_not_wrong … NOT_WRONG) |
---|
2112 | | @(not_return_to_not_final … EV) >IS_CALL % #E destruct |
---|
2113 | ] |
---|
2114 | | inversion NOT_WRONG #H29 #H30 #H31 #H32 #H33 try #H35 try #H36 try #H37 destruct |
---|
2115 | ] qed. |
---|
2116 | |
---|
2117 | definition well_cost_labelled_program : RTLabs_program → Prop ≝ |
---|
2118 | λp. All ? (λx. let 〈id,fd〉 ≝ x in |
---|
2119 | match fd with [ Internal fn ⇒ well_cost_labelled_fn fn | _ ⇒ True]) (prog_funct … p). |
---|
2120 | (* |
---|
2121 | theorem program_trace_exists : |
---|
2122 | termination_oracle → |
---|
2123 | ∀p:RTLabs_program. |
---|
2124 | ∀s:state. |
---|
2125 | ∀I: make_initial_state p = OK ? s. |
---|
2126 | |
---|
2127 | let plain_trace ≝ exec_inf io_out io_in RTLabs_fullexec p in |
---|
2128 | |
---|
2129 | ∀NOIO:exec_no_io … plain_trace. |
---|
2130 | |
---|
2131 | let flat_trace ≝ make_whole_flat_trace p s NOIO I in |
---|
2132 | |
---|
2133 | trace_whole_program_exists (RTLabs_status (make_global p)) s. |
---|
2134 | #ORACLE #p #s #I |
---|
2135 | letin plain_trace ≝ (exec_inf io_out io_in RTLabs_fullexec p) |
---|
2136 | #NOIO |
---|
2137 | letin flat_trace ≝ (make_whole_flat_trace p s NOIO I) |
---|
2138 | whd |
---|
2139 | @(whole_structured_trace_exists … flat_trace) |
---|
2140 | // |
---|
2141 | [ whd |
---|
2142 | *) |
---|
2143 | |
---|
2144 | lemma simplify_exec : ∀ge.∀s,s':RTLabs_state ge. |
---|
2145 | as_execute (RTLabs_status ge) s s' → |
---|
2146 | ∃tr. eval_statement ge s = Value … 〈tr,s'〉. |
---|
2147 | #ge #s #s' * #tr * #EX #_ %{tr} @EX |
---|
2148 | qed. |
---|
2149 | |
---|
2150 | (* as_execute might be in Prop, but because the semantics is deterministic |
---|
2151 | we can retrieve the event trace anyway. *) |
---|
2152 | |
---|
2153 | let rec deprop_execute ge (s,s':state) |
---|
2154 | (X:∃t. eval_statement ge s = Value … 〈t,s'〉) |
---|
2155 | : Σtr. eval_statement ge s = Value … 〈tr,s'〉 ≝ |
---|
2156 | match eval_statement ge s return λE. (∃t.E = ?) → Σt.E = Value … 〈t,s'〉 with |
---|
2157 | [ Value ts ⇒ λY. «fst … ts, ?» |
---|
2158 | | _ ⇒ λY. ⊥ |
---|
2159 | ] X. |
---|
2160 | [ 1,3: cases Y #x #E destruct |
---|
2161 | | cases Y #trP #E destruct @refl |
---|
2162 | ] qed. |
---|
2163 | |
---|
2164 | let rec deprop_as_execute ge (s,s':RTLabs_state ge) |
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2165 | (X:as_execute (RTLabs_status ge) s s') |
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2166 | : Σtr. eval_statement ge s = Value … 〈tr,s'〉 ≝ |
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2167 | deprop_execute ge s s' ?. |
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2168 | cases X #tr * #EX #_ %{tr} @EX |
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2169 | qed. |
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2170 | |
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2171 | (* A non-empty finite section of a flat_trace *) |
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2172 | inductive partial_flat_trace (o:Type[0]) (i:o → Type[0]) (ge:genv) : state → state → Type[0] ≝ |
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2173 | | pft_base : ∀s,tr,s'. eval_statement ge s = Value ??? 〈tr,s'〉 → partial_flat_trace o i ge s s' |
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2174 | | pft_step : ∀s,tr,s',s''. eval_statement ge s = Value ??? 〈tr,s'〉 → partial_flat_trace o i ge s' s'' → partial_flat_trace o i ge s s''. |
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2175 | |
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2176 | let rec append_partial_flat_trace o i ge s1 s2 s3 |
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2177 | (tr1:partial_flat_trace o i ge s1 s2) |
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2178 | on tr1 : partial_flat_trace o i ge s2 s3 → partial_flat_trace o i ge s1 s3 ≝ |
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2179 | match tr1 with |
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2180 | [ pft_base s tr s' EX ⇒ pft_step … s tr s' s3 EX |
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2181 | | pft_step s tr s' s'' EX tr' ⇒ λtr2. pft_step … s tr s' s3 EX (append_partial_flat_trace … tr' tr2) |
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2182 | ]. |
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2183 | |
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2184 | let rec partial_to_flat_trace o i ge s1 s2 |
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2185 | (tr:partial_flat_trace o i ge s1 s2) |
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2186 | on tr : flat_trace o i ge s2 → flat_trace o i ge s1 ≝ |
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2187 | match tr with |
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2188 | [ pft_base s tr s' EX ⇒ ft_step … EX |
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2189 | | pft_step s tr s' s'' EX tr' ⇒ λtr''. ft_step … EX (partial_to_flat_trace … tr' tr'') |
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2190 | ]. |
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2191 | |
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2192 | (* Extract a flat trace from a structured one. *) |
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2193 | let rec flat_trace_of_label_return ge (s,s':RTLabs_state ge) |
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2194 | (tr:trace_label_return (RTLabs_status ge) s s') |
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2195 | on tr : |
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2196 | partial_flat_trace io_out io_in ge s s' ≝ |
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2197 | match tr with |
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2198 | [ tlr_base s1 s2 tll ⇒ flat_trace_of_label_label ge ends_with_ret s1 s2 tll |
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2199 | | tlr_step s1 s2 s3 tll tlr ⇒ |
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2200 | append_partial_flat_trace … |
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2201 | (flat_trace_of_label_label ge doesnt_end_with_ret s1 s2 tll) |
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2202 | (flat_trace_of_label_return ge s2 s3 tlr) |
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2203 | ] |
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2204 | and flat_trace_of_label_label ge ends (s,s':RTLabs_state ge) |
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2205 | (tr:trace_label_label (RTLabs_status ge) ends s s') |
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2206 | on tr : |
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2207 | partial_flat_trace io_out io_in ge s s' ≝ |
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2208 | match tr with |
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2209 | [ tll_base e s1 s2 tal _ ⇒ flat_trace_of_any_label ge e s1 s2 tal |
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2210 | ] |
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2211 | and flat_trace_of_any_label ge ends (s,s':RTLabs_state ge) |
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2212 | (tr:trace_any_label (RTLabs_status ge) ends s s') |
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2213 | on tr : |
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2214 | partial_flat_trace io_out io_in ge s s' ≝ |
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2215 | match tr with |
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2216 | [ tal_base_not_return s1 s2 EX CL CS ⇒ |
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2217 | match deprop_as_execute ge ?? EX with [ mk_Sig tr EX' ⇒ |
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2218 | pft_base … EX' ] |
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2219 | | tal_base_return s1 s2 EX CL ⇒ |
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2220 | match deprop_as_execute ge ?? EX with [ mk_Sig tr EX' ⇒ |
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2221 | pft_base … EX' ] |
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2222 | | tal_base_call s1 s2 s3 EX CL AR tlr CS ⇒ |
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2223 | let suffix' ≝ flat_trace_of_label_return ge ?? tlr in |
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2224 | match deprop_as_execute ge ?? EX with [ mk_Sig tr EX' ⇒ |
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2225 | pft_step … EX' suffix' ] |
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2226 | | tal_step_call ends s1 s2 s3 s4 EX CL AR tlr CS tal ⇒ |
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2227 | match deprop_as_execute ge ?? EX with [ mk_Sig tr EX' ⇒ |
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2228 | pft_step … EX' |
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2229 | (append_partial_flat_trace … |
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2230 | (flat_trace_of_label_return ge ?? tlr) |
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2231 | (flat_trace_of_any_label ge ??? tal)) |
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2232 | ] |
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2233 | | tal_step_default ends s1 s2 s3 EX tal CL CS ⇒ |
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2234 | match deprop_as_execute ge ?? EX with [ mk_Sig tr EX' ⇒ |
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2235 | pft_step … EX' (flat_trace_of_any_label ge ??? tal) |
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2236 | ] |
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2237 | ]. |
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2238 | |
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2239 | |
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2240 | (* We take an extra step so that we can always return a non-empty trace to |
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2241 | satisfy the guardedness condition in the cofixpoint. *) |
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2242 | let rec flat_trace_of_any_call ge (s,s',s'':RTLabs_state ge) et |
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2243 | (tr:trace_any_call (RTLabs_status ge) s s') |
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2244 | (EX'':eval_statement ge s' = Value … 〈et,s''〉) |
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2245 | on tr : |
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2246 | partial_flat_trace io_out io_in ge s s'' ≝ |
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2247 | match tr return λs,s':RTLabs_state ge.λ_. eval_statement ge s' = ? → partial_flat_trace io_out io_in ge s s'' with |
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2248 | [ tac_base s1 CL ⇒ λEX''. pft_base … ge ??? EX'' |
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2249 | | tac_step_call s1 s2 s3 s4 EX CL AR tlr CS tac ⇒ λEX''. |
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2250 | match deprop_as_execute ge ?? EX with [ mk_Sig et EX' ⇒ |
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2251 | pft_step … EX' |
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2252 | (append_partial_flat_trace … |
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2253 | (flat_trace_of_label_return ge ?? tlr) |
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2254 | (flat_trace_of_any_call ge … tac EX'')) |
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2255 | ] |
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2256 | | tac_step_default s1 s2 s3 EX tal CL CS ⇒ λEX''. |
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2257 | match deprop_as_execute ge ?? EX with [ mk_Sig tr EX' ⇒ |
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2258 | pft_step … EX' |
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2259 | (flat_trace_of_any_call ge … tal EX'') |
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2260 | ] |
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2261 | ] EX''. |
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2262 | |
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2263 | let rec flat_trace_of_label_call ge (s,s',s'':RTLabs_state ge) et |
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2264 | (tr:trace_label_call (RTLabs_status ge) s s') |
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2265 | (EX'':eval_statement ge s' = Value … 〈et,s''〉) |
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2266 | on tr : |
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2267 | partial_flat_trace io_out io_in ge s s'' ≝ |
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2268 | match tr with |
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2269 | [ tlc_base s1 s2 tac CS ⇒ flat_trace_of_any_call … tac |
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2270 | ] EX''. |
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2271 | |
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2272 | (* Now reconstruct the flat_trace of a diverging execution. Note that we need |
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2273 | to take care to satisfy the guardedness condition by witnessing the fact that |
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2274 | the partial traces are non-empty. *) |
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2275 | let corec flat_trace_of_label_diverges ge (s:RTLabs_state ge) |
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2276 | (tr:trace_label_diverges (RTLabs_status ge) s) |
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2277 | : flat_trace io_out io_in ge s ≝ |
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2278 | match tr return λs:RTLabs_state ge.λtr:trace_label_diverges (RTLabs_status ge) s. flat_trace io_out io_in ge s with |
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2279 | [ tld_step sx sy tll tld ⇒ |
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2280 | match sy in RTLabs_state return λsy:RTLabs_state ge. trace_label_label (RTLabs_status ge) ? sx sy → trace_label_diverges (RTLabs_status ge) sy → flat_trace io_out io_in ge ? with [ mk_RTLabs_state sy' stk mtc0 ⇒ |
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2281 | λtll. |
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2282 | match flat_trace_of_label_label ge … tll return λs1,s2:state.λ_:partial_flat_trace io_out io_in ge s1 s2. ∀mtc:Ras_Fn_Match ge s2 stk. trace_label_diverges (RTLabs_status ge) (mk_RTLabs_state ge s2 stk mtc) → flat_trace ??? s1 with |
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2283 | [ pft_base s1 tr s2 EX ⇒ λmtc,tld. ft_step … EX (flat_trace_of_label_diverges ge ? tld) |
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2284 | | pft_step s1 et s2 s3 EX tr' ⇒ λmtc,tld. ft_step … EX (add_partial_flat_trace ge … (mk_RTLabs_state ge s3 stk mtc) tr' tld) |
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2285 | ] mtc0 ] tll tld |
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2286 | | tld_base s1 s2 s3 tlc EX CL tld ⇒ |
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2287 | match s3 in RTLabs_state return λs3:RTLabs_state ge. as_execute (RTLabs_status ge) ? s3 → trace_label_diverges (RTLabs_status ge) s3 → flat_trace io_out io_in ge ? with [ mk_RTLabs_state s3' stk mtc0 ⇒ |
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2288 | λEX. match deprop_as_execute ge ?? EX with [ mk_Sig tr EX' ⇒ |
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2289 | match flat_trace_of_label_call … tlc EX' return λs1,s3.λ_. ∀mtc:Ras_Fn_Match ge s3 stk. trace_label_diverges (RTLabs_status ge) (mk_RTLabs_state ge s3 stk mtc) → flat_trace ??? s1 with |
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2290 | [ pft_base s1 tr s2 EX ⇒ λmtc,tld. ft_step … EX (flat_trace_of_label_diverges ge ? tld) |
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2291 | | pft_step s1 et s2 s3 EX tr' ⇒ λmtc,tld. ft_step … EX (add_partial_flat_trace ge … (mk_RTLabs_state ge s3 stk mtc) tr' tld) |
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2292 | ] mtc0 |
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2293 | ] |
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2294 | ] EX tld |
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2295 | ] |
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2296 | (* Helper to keep adding the partial trace without violating the guardedness |
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2297 | condition. *) |
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2298 | and add_partial_flat_trace ge (s:state) (s':RTLabs_state ge) |
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2299 | : partial_flat_trace io_out io_in ge s s' → |
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2300 | trace_label_diverges (RTLabs_status ge) s' → |
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2301 | flat_trace io_out io_in ge s ≝ |
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2302 | match s' return λs':RTLabs_state ge. partial_flat_trace io_out io_in ge s s' → trace_label_diverges (RTLabs_status ge) s' → flat_trace io_out io_in ge s with [ mk_RTLabs_state sx stk mtc ⇒ |
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2303 | λptr. match ptr return λs,s'.λ_. ∀mtc:Ras_Fn_Match ge s' stk. trace_label_diverges (RTLabs_status ge) (mk_RTLabs_state ge s' ? mtc) → flat_trace io_out io_in ge s with |
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2304 | [ pft_base s tr s' EX ⇒ λmtc,tr. ft_step … EX (flat_trace_of_label_diverges ge ? tr) |
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2305 | | pft_step s1 et s2 s3 EX tr' ⇒ λmtc,tr. ft_step … EX (add_partial_flat_trace ge s2 (mk_RTLabs_state ge s3 stk mtc) tr' tr) |
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2306 | ] mtc ] |
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2307 | . |
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2308 | |
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2309 | |
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2310 | coinductive equal_flat_traces (ge:genv) : ∀s. flat_trace io_out io_in ge s → flat_trace io_out io_in ge s → Prop ≝ |
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2311 | | eft_stop : ∀s,F. equal_flat_traces ge s (ft_stop … F) (ft_stop … F) |
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2312 | | eft_step : ∀s,tr,s',EX,tr1,tr2. equal_flat_traces ge s' tr1 tr2 → equal_flat_traces ge s (ft_step … EX tr1) (ft_step … s tr s' EX tr2) |
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2313 | | eft_wrong : ∀s,m,NF,EX. equal_flat_traces ge s (ft_wrong … s m NF EX) (ft_wrong … s m NF EX). |
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2314 | |
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2315 | (* XXX move to semantics *) |
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2316 | lemma final_cannot_move : ∀ge,s. |
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2317 | RTLabs_is_final s ≠ None ? → |
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2318 | ∃err. eval_statement ge s = Wrong ??? err. |
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2319 | #ge * |
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2320 | [ #f #fs #m * #F cases (F ?) @refl |
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2321 | | #a #b #c #d #e * #F cases (F ?) @refl |
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2322 | | #a #b #c #d * #F cases (F ?) @refl |
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2323 | | #r #F % [2: @refl | skip ] |
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2324 | ] qed. |
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2325 | |
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2326 | let corec flat_traces_are_determined_by_starting_point ge s tr1 |
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2327 | : ∀tr2. equal_flat_traces ge s tr1 tr2 ≝ |
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2328 | match tr1 return λs,tr1. flat_trace ??? s → equal_flat_traces ? s tr1 ? with |
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2329 | [ ft_stop s F ⇒ λtr2. ? |
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2330 | | ft_step s1 tr s2 EX0 tr1' ⇒ λtr2. |
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2331 | match tr2 return λs,tr2. ∀EX:eval_statement ge s = ?. equal_flat_traces ? s (ft_step ??? s ?? EX ?) tr2 with |
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2332 | [ ft_stop s F ⇒ λEX. ? |
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2333 | | ft_step s tr' s2' EX' tr2' ⇒ λEX. ? |
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2334 | | ft_wrong s m NF EX' ⇒ λEX. ? |
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2335 | ] EX0 |
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2336 | | ft_wrong s m NF EX ⇒ λtr2. ? |
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2337 | ]. |
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2338 | [ inversion tr2 in tr1 F; |
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2339 | [ #s #F #_ #_ #tr1 #F' @eft_stop |
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2340 | | #s1 #tr #s2 #EX #tr' #E #_ #tr'' #F' @⊥ destruct |
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2341 | cases (final_cannot_move ge … F') #err #Er >Er in EX; #E destruct |
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2342 | | #s #m #NF #EX #_ #_ #_ #F @⊥ >NF in F; * /2/ |
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2343 | ] |
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2344 | | @⊥ cases (final_cannot_move ge … F) #err #Er >Er in EX; #E destruct |
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2345 | | -EX0 |
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2346 | cut (s2 = s2'). >EX in EX'; #E destruct @refl. #E (* Can't use destruct due to cofixpoint guardedness check *) |
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2347 | @(match E return λs2',E. ∀tr2':flat_trace ??? s2'. ∀EX':? = Value ??? 〈?,s2'〉. equal_flat_traces ??? (ft_step ????? s2' EX' tr2') with [ refl ⇒ ? ] tr2' EX') |
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2348 | -E -EX' -tr2' #tr2' #EX' |
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2349 | cut (tr = tr'). >EX in EX'; #E destruct @refl. #E (* Can't use destruct due to cofixpoint guardedness check *) |
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2350 | @(match E return λtr',E. ∀EX':? = Value ??? 〈tr',?〉. equal_flat_traces ??? (ft_step ???? tr' ? EX' ?) with [ refl ⇒ ? ] EX') |
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2351 | -E -EX' #EX' |
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2352 | @eft_step @flat_traces_are_determined_by_starting_point |
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2353 | | @⊥ >EX in EX'; #E destruct |
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2354 | | inversion tr2 in NF EX; |
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2355 | [ #s #F #_ #_ #NF @⊥ >NF in F; * /2/ |
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2356 | | #s1 #tr #s2 #EX #tr1 #E1 #_ #NF #EX' @⊥ >EX in EX'; #E destruct |
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2357 | | #sx #m' #NF #EX #_ #_ #NF' #EX' cut (m=m'). >EX in EX'; #E destruct @refl. |
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2358 | #E destruct |
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2359 | @eft_wrong |
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2360 | ] |
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2361 | ] qed. |
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2362 | |
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2363 | let corec diverging_traces_have_unique_flat_trace ge (s:RTLabs_state ge) |
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2364 | (str:trace_label_diverges (RTLabs_status ge) s) |
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2365 | (tr:flat_trace io_out io_in ge s) |
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2366 | : equal_flat_traces … (flat_trace_of_label_diverges … str) tr ≝ ?. |
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2367 | @flat_traces_are_determined_by_starting_point |
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2368 | qed. |
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2369 | |
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2370 | let rec flat_trace_of_whole_program ge (s:RTLabs_state ge) |
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2371 | (tr:trace_whole_program (RTLabs_status ge) s) |
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2372 | on tr : flat_trace io_out io_in ge s ≝ |
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2373 | match tr return λs:RTLabs_state ge.λtr. flat_trace io_out io_in ge s with |
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2374 | [ twp_terminating s1 s2 sf CL EX tlr F ⇒ |
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2375 | match deprop_as_execute ge ?? EX with [ mk_Sig tr EX' ⇒ |
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2376 | ft_step … EX' (partial_to_flat_trace … (flat_trace_of_label_return … tlr) (ft_stop … F)) |
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2377 | ] |
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2378 | | twp_diverges s1 s2 CL EX tld ⇒ |
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2379 | match deprop_as_execute ge ?? EX with [ mk_Sig tr EX' ⇒ |
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2380 | ft_step … EX' (flat_trace_of_label_diverges … tld) |
---|
2381 | ] |
---|
2382 | ]. |
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2383 | |
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2384 | let corec whole_traces_have_unique_flat_trace ge (s:RTLabs_state ge) |
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2385 | (str:trace_whole_program (RTLabs_status ge) s) |
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2386 | (tr:flat_trace io_out io_in ge s) |
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2387 | : equal_flat_traces … (flat_trace_of_whole_program … str) tr ≝ ?. |
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2388 | @flat_traces_are_determined_by_starting_point |
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2389 | qed. |
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