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| author | Xavier Leroy <xavier.leroy@college-de-france.fr> | 2020-02-18 16:57:17 +0100 |
|---|---|---|
| committer | Xavier Leroy <xavierleroy@users.noreply.github.com> | 2020-02-21 13:29:39 +0100 |
| commit | be0b1872bf2ad36df9b0c7a0ffa63b9e77fa769b (patch) | |
| tree | 0d54cce547d12567d7e9e9f2c4d650e5a1b94b39 /backend/Cminor.v | |
| parent | a9eaf4897c825093aba2137ff76e56bfbf1e72d5 (diff) | |
| download | compcert-kvx-be0b1872bf2ad36df9b0c7a0ffa63b9e77fa769b.tar.gz compcert-kvx-be0b1872bf2ad36df9b0c7a0ffa63b9e77fa769b.zip | |
Refine the type of function results in AST.signature
Before it was "option typ". Now it is a proper inductive type
that can also express small integer types (8/16-bit unsigned/signed integers).
One benefit is that external functions get more precise types that
control better their return values. As a consequence,
the CompCert C type preservation property now holds unconditionally,
without extra typing hypotheses on external functions.
Diffstat (limited to 'backend/Cminor.v')
| -rw-r--r-- | backend/Cminor.v | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/backend/Cminor.v b/backend/Cminor.v index ca01ad50..91a4c104 100644 --- a/backend/Cminor.v +++ b/backend/Cminor.v @@ -676,12 +676,24 @@ Definition outcome_block (out: outcome) : outcome := | out => out end. +(* Definition outcome_result_value - (out: outcome) (retsig: option typ) (vres: val) : Prop := + (out: outcome) (retsig: rettype) (vres: val) : Prop := match out with | Out_normal => vres = Vundef | Out_return None => vres = Vundef - | Out_return (Some v) => retsig <> None /\ vres = v + | Out_return (Some v) => retsig <> Tvoid /\ vres = v + | Out_tailcall_return v => vres = v + | _ => False + end. +*) + +Definition outcome_result_value + (out: outcome) (vres: val) : Prop := + match out with + | Out_normal => vres = Vundef + | Out_return None => vres = Vundef + | Out_return (Some v) => vres = v | Out_tailcall_return v => vres = v | _ => False end. @@ -711,7 +723,7 @@ Inductive eval_funcall: Mem.alloc m 0 f.(fn_stackspace) = (m1, sp) -> set_locals f.(fn_vars) (set_params vargs f.(fn_params)) = e -> exec_stmt f (Vptr sp Ptrofs.zero) e m1 f.(fn_body) t e2 m2 out -> - outcome_result_value out f.(fn_sig).(sig_res) vres -> + outcome_result_value out vres -> outcome_free_mem out m2 sp f.(fn_stackspace) m3 -> eval_funcall m (Internal f) vargs t m3 vres | eval_funcall_external: @@ -995,7 +1007,7 @@ Proof. subst vres. replace k with (call_cont k') by congruence. apply star_one. apply step_return_0; auto. (* Out_return Some *) - destruct H3. subst vres. + subst vres. replace k with (call_cont k') by congruence. apply star_one. eapply step_return_1; eauto. (* Out_tailcall_return *) |