Fix handling of C99 "extern inline" semantics when dealing with
multiple declarations of the function. Should fix PR3989 and
<rdar://problem/6818429>.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69905 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index c7a45dc..b359208 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -833,7 +833,21 @@
// Merge the storage class.
New->setStorageClass(Old->getStorageClass());
- // FIXME: need to implement inline semantics
+ // Merge "inline"
+ if (Old->isInline())
+ New->setInline(true);
+
+ // If this function declaration by itself qualifies as a C99 inline
+ // definition (C99 6.7.4p6), but the previous definition did not,
+ // then the function is not a C99 inline definition.
+ if (New->isC99InlineDefinition() && !Old->isC99InlineDefinition())
+ New->setC99InlineDefinition(false);
+ else if (Old->isC99InlineDefinition() && !New->isC99InlineDefinition()) {
+ // Mark all preceding definitions as not being C99 inline definitions.
+ for (const FunctionDecl *Prev = Old; Prev;
+ Prev = Prev->getPreviousDeclaration())
+ const_cast<FunctionDecl *>(Prev)->setC99InlineDefinition(false);
+ }
// Merge "pure" flag.
if (Old->isPure())
@@ -2177,6 +2191,19 @@
isOutOfScopePreviousDeclaration(PrevDecl, DC, Context)))
PrevDecl = 0;
+ // FIXME: We need to determine whether the GNU inline attribute will
+ // be applied to this function declaration, since it affects
+ // declaration merging. This hack will go away when the FIXME below
+ // is resolved, since we should be putting *all* attributes onto the
+ // declaration now.
+ for (const AttributeList *Attr = D.getDeclSpec().getAttributes();
+ Attr; Attr = Attr->getNext()) {
+ if (Attr->getKind() == AttributeList::AT_gnu_inline) {
+ NewFD->addAttr(::new (Context) GNUInlineAttr());
+ break;
+ }
+ }
+
// Perform semantic checking on the function declaration.
bool OverloadableAttrRequired = false; // FIXME: HACK!
if (CheckFunctionDeclaration(NewFD, PrevDecl, Redeclaration,
@@ -2292,6 +2319,32 @@
InvalidDecl = true;
}
+ // C99 6.7.4p6:
+ // [... ] For a function with external linkage, the following
+ // restrictions apply: [...] If all of the file scope declarations
+ // for a function in a translation unit include the inline
+ // function specifier without extern, then the definition in that
+ // translation unit is an inline definition. An inline definition
+ // does not provide an external definition for the function, and
+ // does not forbid an external definition in another translation
+ // unit.
+ //
+ // Here we determine whether this function, in isolation, would be a
+ // C99 inline definition. MergeCompatibleFunctionDecls looks at
+ // previous declarations.
+ if (NewFD->isInline() &&
+ NewFD->getDeclContext()->getLookupContext()->isTranslationUnit()) {
+ bool GNUInline = NewFD->hasAttr<GNUInlineAttr>() ||
+ (PrevDecl && PrevDecl->hasAttr<GNUInlineAttr>());
+ if (GNUInline || (!getLangOptions().CPlusPlus && !getLangOptions().C99)) {
+ // GNU "extern inline" is the same as "inline" in C99.
+ if (NewFD->getStorageClass() == FunctionDecl::Extern)
+ NewFD->setC99InlineDefinition(true);
+ } else if (getLangOptions().C99 &&
+ NewFD->getStorageClass() == FunctionDecl::None)
+ NewFD->setC99InlineDefinition(true);
+ }
+
// Check for a previous declaration of this name.
if (!PrevDecl && NewFD->isExternC(Context)) {
// Since we did not find anything by this name and we're declaring
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index d0c0ab8..d05b99a 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -1474,7 +1474,11 @@
return;
}
- d->addAttr(::new (S.Context) GNUInlineAttr());
+ // FIXME: We only do this because of the hack in
+ // Sema::ActOnFunctionDeclarator, which needs to add the
+ // GNUInlineAttr early.
+ if (!d->hasAttr<GNUInlineAttr>())
+ d->addAttr(::new (S.Context) GNUInlineAttr());
}
static void HandleRegparmAttr(Decl *d, const AttributeList &Attr, Sema &S) {