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| author | Xavier Leroy <xavier.leroy@college-de-france.fr> | 2019-02-12 11:25:22 +0100 |
|---|---|---|
| committer | Xavier Leroy <xavierleroy@users.noreply.github.com> | 2019-02-25 17:15:36 +0100 |
| commit | 0616171c89d3db651b6842338fdf2da9da885aa1 (patch) | |
| tree | f3915dd053050785277c93e8647f13f7202b53e2 /cparser/Cutil.mli | |
| parent | 3881d799d23bcc0cbaaa9e6bfa82c5bc3b2030eb (diff) | |
| download | compcert-kvx-0616171c89d3db651b6842338fdf2da9da885aa1.tar.gz compcert-kvx-0616171c89d3db651b6842338fdf2da9da885aa1.zip | |
Do not expand type names when floating attributes "up" a declaration
During elaboration of type declarators, non-type-related attributes such as "aligned" or "section" are "floated up" so that they apply to the thing being declared. For example, consider:
```
__attribute((aligned(16))) int * p;
```
The attribute is first attached to type `int`, then floated up to type `int *`, so that it finally applies to `p`, giving a 16-aligned pointer to int, and not a naturally-aligned pointer to 16-aligned int.
What happens when the non-type-related attribute comes from a typedef?
```
typedef __attribute((aligned(16))) int i16;
i16 * p;
```
CompCert used to expand the typedef then float up the attribute, resulting in `p` being a 16-aligned pointer to int.
GCC and Clang produce a naturally-aligned pointer, so they do not expand the typedef before floating.
The old CompCert behavior is somewhat surprising, and potentially less useful than the GCC/Clang behavior.
This commit changes the floating up of non-type-related attributes so that typedefs and struct/union/enum definitions are not expanded when determining which attributes to float up. This is a first step towards mimicking the GCC/Clang behavior.
Diffstat (limited to 'cparser/Cutil.mli')
| -rw-r--r-- | cparser/Cutil.mli | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/cparser/Cutil.mli b/cparser/Cutil.mli index dc9dc0cc..a99bf3af 100644 --- a/cparser/Cutil.mli +++ b/cparser/Cutil.mli @@ -50,6 +50,8 @@ val remove_custom_attributes : string list -> attributes -> attributes in the given list of names. *) val attributes_of_type : Env.t -> typ -> attributes (* Return the attributes of the given type, expanding typedefs if needed. *) +val attributes_of_type_no_expand : typ -> attributes + (* Return the attributes of the given type, without expanding typedefs. *) val add_attributes_type : attributes -> typ -> typ (* Add the given set of attributes to those of the given type. *) val remove_attributes_type : Env.t -> attributes -> typ -> typ |