When deciding whether a deferred declaration has already been emitted,

aliases count as definitions regardless of whether their target has been
emitted yet.  Fixes PR 7142.

llvm-svn: 104796

1 files changed, 13 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 1b89d622420..103024c3239 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -513,9 +513,14 @@ void CodeGenModule::EmitDeferred() {
     GlobalDecl D = DeferredDeclsToEmit.back();
     DeferredDeclsToEmit.pop_back();
 
-    // Look it up to see if it was defined with a stronger definition (e.g. an
-    // extern inline function with a strong function redefinition).  If so,
-    // just ignore the deferred decl.
+    // Check to see if we've already emitted this.  This is necessary
+    // for a couple of reasons: first, decls can end up in the
+    // deferred-decls queue multiple times, and second, decls can end
+    // up with definitions in unusual ways (e.g. by an extern inline
+    // function acquiring a strong function redefinition).  Just
+    // ignore these cases.
+    //
+    // TODO: That said, looking this up multiple times is very wasteful.
     MangleBuffer Name;
     getMangledName(Name, D);
     llvm::GlobalValue *CGRef = GetGlobalValue(Name);
@@ -524,6 +529,11 @@ void CodeGenModule::EmitDeferred() {
     if (!CGRef->isDeclaration())
       continue;
 
+    // GlobalAlias::isDeclaration() defers to the aliasee, but for our
+    // purposes an alias counts as a definition.
+    if (isa<llvm::GlobalAlias>(CGRef))
+      continue;
+
     // Otherwise, emit the definition and move on to the next one.
     EmitGlobalDefinition(D);
   }