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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 /common/Memtype.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 'common/Memtype.v')
| -rw-r--r-- | common/Memtype.v | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/common/Memtype.v b/common/Memtype.v index 53775d8b..ca9c6f1f 100644 --- a/common/Memtype.v +++ b/common/Memtype.v @@ -300,6 +300,11 @@ Axiom load_type: load chunk m b ofs = Some v -> Val.has_type v (type_of_chunk chunk). +Axiom load_rettype: + forall m chunk b ofs v, + load chunk m b ofs = Some v -> + Val.has_rettype v (rettype_of_chunk chunk). + (** For a small integer or float type, the value returned by [load] is invariant under the corresponding cast. *) Axiom load_cast: |