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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/Allocproof.v | |
| parent | a9eaf4897c825093aba2137ff76e56bfbf1e72d5 (diff) | |
| download | compcert-be0b1872bf2ad36df9b0c7a0ffa63b9e77fa769b.tar.gz compcert-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/Allocproof.v')
| -rw-r--r-- | backend/Allocproof.v | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/backend/Allocproof.v b/backend/Allocproof.v index 1804f46b..51755912 100644 --- a/backend/Allocproof.v +++ b/backend/Allocproof.v @@ -1301,10 +1301,10 @@ Proof. Qed. Lemma add_equations_res_lessdef: - forall r oty l e e' rs ls, - add_equations_res r oty l e = Some e' -> + forall r ty l e e' rs ls, + add_equations_res r ty l e = Some e' -> satisf rs ls e' -> - Val.has_type rs#r (match oty with Some ty => ty | None => Tint end) -> + Val.has_type rs#r ty -> Val.lessdef rs#r (Locmap.getpair (map_rpair R l) ls). Proof. intros. functional inversion H; simpl. @@ -1892,7 +1892,7 @@ Qed. Inductive match_stackframes: list RTL.stackframe -> list LTL.stackframe -> signature -> Prop := | match_stackframes_nil: forall sg, - sg.(sig_res) = Some Tint -> + sg.(sig_res) = Tint -> match_stackframes nil nil sg | match_stackframes_cons: forall res f sp pc rs s tf bb ls ts sg an e env @@ -2425,13 +2425,13 @@ Proof. (return_regs (parent_locset ts) ls1)) with (Locmap.getpair (map_rpair R (loc_result (RTL.fn_sig f))) ls1). eapply add_equations_res_lessdef; eauto. - rewrite H13. apply WTRS. + rewrite <- H14. apply WTRS. generalize (loc_result_caller_save (RTL.fn_sig f)). destruct (loc_result (RTL.fn_sig f)); simpl. intros A; rewrite A; auto. intros [A B]; rewrite A, B; auto. apply return_regs_agree_callee_save. - unfold proj_sig_res. rewrite <- H11; rewrite H13. apply WTRS. + rewrite <- H11, <- H14. apply WTRS. (* internal function *) - monadInv FUN. simpl in *. @@ -2463,7 +2463,8 @@ Proof. simpl. destruct (loc_result (ef_sig ef)) eqn:RES; simpl. rewrite Locmap.gss; auto. generalize (loc_result_pair (ef_sig ef)); rewrite RES; intros (A & B & C & D & E). - exploit external_call_well_typed; eauto. unfold proj_sig_res; rewrite B. intros WTRES'. + assert (WTRES': Val.has_type v' Tlong). + { rewrite <- B. eapply external_call_well_typed; eauto. } rewrite Locmap.gss. rewrite Locmap.gso by (red; auto). rewrite Locmap.gss. rewrite val_longofwords_eq_1 by auto. auto. red; intros. rewrite (AG l H0). |