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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 /riscV | |
| 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 'riscV')
| -rw-r--r-- | riscV/Builtins1.v | 2 | ||||
| -rw-r--r-- | riscV/Conventions1.v | 21 |
2 files changed, 11 insertions, 12 deletions
diff --git a/riscV/Builtins1.v b/riscV/Builtins1.v index f6e643d2..53c83d7e 100644 --- a/riscV/Builtins1.v +++ b/riscV/Builtins1.v @@ -29,5 +29,5 @@ Definition platform_builtin_table : list (string * platform_builtin) := Definition platform_builtin_sig (b: platform_builtin) : signature := match b with end. -Definition platform_builtin_sem (b: platform_builtin) : builtin_sem (proj_sig_res (platform_builtin_sig b)) := +Definition platform_builtin_sem (b: platform_builtin) : builtin_sem (sig_res (platform_builtin_sig b)) := match b with end. diff --git a/riscV/Conventions1.v b/riscV/Conventions1.v index df7ddfd2..09cbbb44 100644 --- a/riscV/Conventions1.v +++ b/riscV/Conventions1.v @@ -115,11 +115,10 @@ Definition is_float_reg (r: mreg) := with one integer result. *) Definition loc_result (s: signature) : rpair mreg := - match s.(sig_res) with - | None => One R10 - | Some (Tint | Tany32) => One R10 - | Some (Tfloat | Tsingle | Tany64) => One F10 - | Some Tlong => if Archi.ptr64 then One R10 else Twolong R11 R10 + match proj_sig_res s with + | Tint | Tany32 => One R10 + | Tfloat | Tsingle | Tany64 => One F10 + | Tlong => if Archi.ptr64 then One R10 else Twolong R11 R10 end. (** The result registers have types compatible with that given in the signature. *) @@ -128,8 +127,8 @@ Lemma loc_result_type: forall sig, subtype (proj_sig_res sig) (typ_rpair mreg_type (loc_result sig)) = true. Proof. - intros. unfold proj_sig_res, loc_result, mreg_type; - destruct (sig_res sig) as [[]|]; auto; destruct Archi.ptr64; auto. + intros. unfold loc_result, mreg_type; + destruct (proj_sig_res sig); auto; destruct Archi.ptr64; auto. Qed. (** The result locations are caller-save registers *) @@ -139,7 +138,7 @@ Lemma loc_result_caller_save: forall_rpair (fun r => is_callee_save r = false) (loc_result s). Proof. intros. unfold loc_result, is_callee_save; - destruct (sig_res s) as [[]|]; simpl; auto; destruct Archi.ptr64; simpl; auto. + destruct (proj_sig_res s); simpl; auto; destruct Archi.ptr64; simpl; auto. Qed. (** If the result is in a pair of registers, those registers are distinct and have type [Tint] at least. *) @@ -149,13 +148,13 @@ Lemma loc_result_pair: match loc_result sg with | One _ => True | Twolong r1 r2 => - r1 <> r2 /\ sg.(sig_res) = Some Tlong + r1 <> r2 /\ proj_sig_res sg = Tlong /\ subtype Tint (mreg_type r1) = true /\ subtype Tint (mreg_type r2) = true /\ Archi.ptr64 = false end. Proof. intros. - unfold loc_result; destruct (sig_res sg) as [[]|]; auto. + unfold loc_result; destruct (proj_sig_res sg); auto. unfold mreg_type; destruct Archi.ptr64; auto. split; auto. congruence. Qed. @@ -165,7 +164,7 @@ Qed. Lemma loc_result_exten: forall s1 s2, s1.(sig_res) = s2.(sig_res) -> loc_result s1 = loc_result s2. Proof. - intros. unfold loc_result. rewrite H; auto. + intros. unfold loc_result, proj_sig_res. rewrite H; auto. Qed. (** ** Location of function arguments *) |