CodeGen: Emit some functions as weak_odr under -fms-compatibility
Summary:
MSVC always emits inline functions marked with the extern storage class
specifier. The result is something similar to the opposite of
__attribute__((gnu_inline)).
This extension is also available in C.
This fixes PR19264.
Reviewers: rnk, rsmith
CC: cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D3207
llvm-svn: 205485
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 83cbb44..13681dd 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2546,6 +2546,37 @@
return NumRequiredArgs;
}
+/// \brief The combination of the extern and inline keywords under MSVC forces
+/// the function to be required.
+///
+/// Note: This function assumes that we will only get called when isInlined()
+/// would return true for this FunctionDecl.
+bool FunctionDecl::isMSExternInline() const {
+ assert(isInlined() && "expected to get called on an inlined function!");
+
+ const ASTContext &Context = getASTContext();
+ if (!Context.getLangOpts().MSVCCompat)
+ return false;
+
+ for (const FunctionDecl *FD = this; FD; FD = FD->getPreviousDecl())
+ if (FD->getStorageClass() == SC_Extern)
+ return true;
+
+ return false;
+}
+
+static bool redeclForcesDefMSVC(const FunctionDecl *Redecl) {
+ if (Redecl->getStorageClass() != SC_Extern)
+ return false;
+
+ for (const FunctionDecl *FD = Redecl->getPreviousDecl(); FD;
+ FD = FD->getPreviousDecl())
+ if (FD->getStorageClass() == SC_Extern)
+ return false;
+
+ return true;
+}
+
static bool RedeclForcesDefC99(const FunctionDecl *Redecl) {
// Only consider file-scope declarations in this test.
if (!Redecl->getLexicalDeclContext()->isTranslationUnit())
@@ -2565,7 +2596,7 @@
/// \brief For a function declaration in C or C++, determine whether this
/// declaration causes the definition to be externally visible.
///
-/// Specifically, this determines if adding the current declaration to the set
+/// For instance, this determines if adding the current declaration to the set
/// of redeclarations of the given functions causes
/// isInlineDefinitionExternallyVisible to change from false to true.
bool FunctionDecl::doesDeclarationForceExternallyVisibleDefinition() const {
@@ -2574,6 +2605,13 @@
ASTContext &Context = getASTContext();
+ if (Context.getLangOpts().MSVCCompat) {
+ const FunctionDecl *Definition;
+ if (hasBody(Definition) && Definition->isInlined() &&
+ redeclForcesDefMSVC(this))
+ return true;
+ }
+
if (Context.getLangOpts().GNUInline || hasAttr<GNUInlineAttr>()) {
// With GNU inlining, a declaration with 'inline' but not 'extern', forces
// an externally visible definition.