From 76fe50c654df0f35fd93335b93d9a101fd1b8dfd Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Tue, 28 Apr 2009 06:37:30 +0000
Subject: Improve compatibility with GCC regarding inline semantics in GNU89
 mode and in the presence of __gnu_inline__ attributes. This should fix both
 PR3989 and PR4069.

As part of this, we now keep track of all of the attributes attached
to each declaration even after we've performed declaration
merging. This fixes PR3264.

llvm-svn: 70292
---
 clang/lib/Sema/SemaDecl.cpp | 51 ++++++++++-----------------------------------
 1 file changed, 11 insertions(+), 40 deletions(-)

(limited to 'clang/lib/Sema/SemaDecl.cpp')

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index b46dd5547fe..4427f0de1f2 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -584,22 +584,13 @@ static bool DeclHasAttr(const Decl *decl, const Attr *target) {
 
 /// MergeAttributes - append attributes from the Old decl to the New one.
 static void MergeAttributes(Decl *New, Decl *Old, ASTContext &C) {
-  Attr *attr = const_cast<Attr*>(Old->getAttrs());
-
-  while (attr) {
-    Attr *tmp = attr;
-    attr = attr->getNext();
-
-    if (!DeclHasAttr(New, tmp) && tmp->isMerged()) {
-      tmp->setInherited(true);
-      New->addAttr(tmp);
-    } else {
-      tmp->setNext(0);
-      tmp->Destroy(C);
+  for (const Attr *attr = Old->getAttrs(); attr; attr = attr->getNext()) {
+    if (!DeclHasAttr(New, attr) && attr->isMerged()) {
+      Attr *NewAttr = attr->clone(C);
+      NewAttr->setInherited(true);
+      New->addAttr(NewAttr);
     }
   }
-
-  Old->invalidateAttrs();
 }
 
 /// Used in MergeFunctionDecl to keep track of function parameters in
@@ -851,7 +842,8 @@ bool Sema::MergeCompatibleFunctionDecls(FunctionDecl *New, FunctionDecl *Old) {
   MergeAttributes(New, Old, Context);
 
   // Merge the storage class.
-  New->setStorageClass(Old->getStorageClass());
+  if (Old->getStorageClass() != FunctionDecl::Extern)
+    New->setStorageClass(Old->getStorageClass());
 
   // Merge "inline"
   if (Old->isInline())
@@ -2186,19 +2178,6 @@ Sema::ActOnFunctionDeclarator(Scope* S, Declarator& D, DeclContext* DC,
         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!
   CheckFunctionDeclaration(NewFD, PrevDecl, Redeclaration,
@@ -2328,18 +2307,10 @@ void Sema::CheckFunctionDeclaration(FunctionDecl *NewFD, NamedDecl *&PrevDecl,
   // 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);
-  }           
+  if (NewFD->isInline() && getLangOptions().C99 && 
+      NewFD->getStorageClass() == FunctionDecl::None &&
+      NewFD->getDeclContext()->getLookupContext()->isTranslationUnit())
+    NewFD->setC99InlineDefinition(true);
 
   // Check for a previous declaration of this name.
   if (!PrevDecl && NewFD->isExternC(Context)) {
-- 
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