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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/Elab.ml | |
| 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/Elab.ml')
| -rw-r--r-- | cparser/Elab.ml | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/cparser/Elab.ml b/cparser/Elab.ml index 8f27b2a0..8f42fe0a 100644 --- a/cparser/Elab.ml +++ b/cparser/Elab.ml @@ -598,7 +598,7 @@ let get_nontype_attrs env ty = | Attr_type -> false | Attr_function -> not (is_function_type env ty) | _ -> true in - let nta = List.filter to_be_removed (attributes_of_type env ty) in + let nta = List.filter to_be_removed (attributes_of_type_no_expand ty) in (remove_attributes_type env nta ty, nta) (* Elaboration of a type specifier. Returns 6-tuple: |