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Without this patch clang warns on 

struct __attribute__((visibility("hidden"))) zed {
};
struct __attribute__((visibility("hidden"))) zed;

Which is a bit silly and got a lot noisier now that we correctly handle
visibility pragmas. This patch fixes that and also has some extra quality
improvements:

* We now produce an error instead of a warning for

struct __attribute__((visibility("hidden"))) zed {
};
struct __attribute__((visibility("default"))) zed;

* The "after definition" warning now points to the new attribute that is
  ignored instead of pointing to the declaration.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160227 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rafael Espindola 2012-07-15 01:33:40 +00:00
parent 4b044c6bc7
commit d320ffc0f5
2 changed files with 54 additions and 7 deletions
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42
lib/Sema/SemaDecl.cpp
View File

@ -1767,16 +1767,46 @@ static const Decl *getDefinition(const Decl *D) {
return NULL;
}
static bool hasAttribute(const Decl *D, attr::Kind Kind) {
for (Decl::attr_iterator I = D->attr_begin(), E = D->attr_end();
I != E; ++I) {
Attr *Attribute = *I;
if (Attribute->getKind() == Kind)
return true;
}
return false;
}
/// checkNewAttributesAfterDef - If we already have a definition, check that
/// there are no new attributes in this declaration.
static void checkNewAttributesAfterDef(Sema &S, Decl *New, const Decl *Old) {
if (!New->hasAttrs())
return;
const Decl *Def = getDefinition(Old);
if (!Def || Def == New)
return;
AttrVec &NewAttributes = New->getAttrs();
for (unsigned I = 0, E = NewAttributes.size(); I != E;) {
const Attr *NewAttribute = NewAttributes[I];
if (hasAttribute(Def, NewAttribute->getKind())) {
++I;
continue; // regular attr merging will take care of validating this.
}
S.Diag(NewAttribute->getLocation(),
diag::warn_attribute_precede_definition);
S.Diag(Def->getLocation(), diag::note_previous_definition);
NewAttributes.erase(NewAttributes.begin() + I);
--E;
}
}
/// mergeDeclAttributes - Copy attributes from the Old decl to the New one.
void Sema::mergeDeclAttributes(Decl *New, Decl *Old,
bool MergeDeprecation) {
// attributes declared post-definition are currently ignored
const Decl *Def = getDefinition(Old);
if (Def && Def != New && New->hasAttrs()) {
Diag(New->getLocation(), diag::warn_attribute_precede_definition);
Diag(Def->getLocation(), diag::note_previous_definition);
New->dropAttrs();
}
checkNewAttributesAfterDef(*this, New, Old);
if (!Old->hasAttrs())
return;

19
test/Sema/attr-decl-after-definition.c
View File

@ -14,9 +14,26 @@ int bar __attribute__((weak));
int bar __attribute__((used));
extern int bar __attribute__((weak));
int bar = 0; // expected-note {{previous definition is here}}
int bar __attribute__((weak)); // expected-warning {{must precede definition}}
int bar __attribute__((weak)); // no warning as it matches the existing
// attribute.
int bar __attribute__((used,
visibility("hidden"))); // expected-warning {{must precede definition}}
int bar;
struct zed { // expected-note {{previous definition is here}}
};
struct __attribute__((visibility("hidden"))) zed; // expected-warning {{must precede definition}}
struct __attribute__((visibility("hidden"))) zed2 {
};
struct __attribute__((visibility("hidden"))) zed2;
struct __attribute__((visibility("hidden"))) zed3 { // expected-note {{previous definition is here}}
};
struct __attribute__((visibility("hidden"),
packed // expected-warning {{must precede definition}}
)) zed3;
struct __attribute__((visibility("hidden"))) zed4 { // expected-note {{previous attribute is here}}
};
struct __attribute__((visibility("default"))) zed4; // expected-error {{visibility does not match previous declaration}}