Explictly track tentative definitions within Sema, then hand those

tentative definitions off to the ASTConsumer at the end of the
translation unit. 

Eliminate CodeGen's internal tracking of tentative definitions, and
instead hook into ASTConsumer::CompleteTentativeDefinition. Also,
tweak the definition-deferal logic for C++, where there are no
tentative definitions.

Fixes <rdar://problem/6808352>, and will make it much easier for
precompiled headers to cope with tentative definitions in the future.

llvm-svn: 69681

1 files changed, 32 insertions, 33 deletions

diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index ed5c431da82..19155b6cc34 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "Sema.h"
+#include "clang/AST/ASTConsumer.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/Expr.h"
@@ -232,41 +233,39 @@ void Sema::ActOnEndOfTranslationUnit() {
   //   translation unit contains a file scope declaration of that
   //   identifier, with the composite type as of the end of the
   //   translation unit, with an initializer equal to 0.
-  if (!getLangOptions().CPlusPlus) {
-    // Note: we traverse the scope's list of declarations rather than
-    // the DeclContext's list, because we only want to see the most
-    // recent declaration of each identifier.
-    for (Scope::decl_iterator I = TUScope->decl_begin(),
-         IEnd = TUScope->decl_end();
-         I != IEnd; ++I) {
-      Decl *D = (*I).getAs<Decl>();
-      if (D->isInvalidDecl())
-        continue;
+  for (llvm::DenseMap<DeclarationName, VarDecl *>::iterator 
+         D = TentativeDefinitions.begin(),
+         DEnd = TentativeDefinitions.end();
+       D != DEnd; ++D) {
+    VarDecl *VD = D->second;
 
-      if (VarDecl *VD = dyn_cast<VarDecl>(D)) {
-        if (VD->isTentativeDefinition(Context)) {
-          if (const IncompleteArrayType *ArrayT 
-                = Context.getAsIncompleteArrayType(VD->getType())) {
-            if (RequireCompleteType(VD->getLocation(), 
-                                    ArrayT->getElementType(),
-                                 diag::err_tentative_def_incomplete_type_arr))
-              VD->setInvalidDecl();
-            else {
-              // Set the length of the array to 1 (C99 6.9.2p5).
-              Diag(VD->getLocation(),  diag::warn_tentative_incomplete_array);
-              llvm::APInt One(Context.getTypeSize(Context.getSizeType()), 
-                              true);
-              QualType T 
-                = Context.getConstantArrayType(ArrayT->getElementType(),
-                                               One, ArrayType::Normal, 0);
-              VD->setType(T);
-            }
-          } else if (RequireCompleteType(VD->getLocation(), VD->getType(), 
-                                    diag::err_tentative_def_incomplete_type))
-            VD->setInvalidDecl();
-        }
+    if (VD->isInvalidDecl() || !VD->isTentativeDefinition(Context))
+      continue;
+
+    if (const IncompleteArrayType *ArrayT 
+        = Context.getAsIncompleteArrayType(VD->getType())) {
+      if (RequireCompleteType(VD->getLocation(), 
+                              ArrayT->getElementType(),
+                              diag::err_tentative_def_incomplete_type_arr))
+        VD->setInvalidDecl();
+      else {
+        // Set the length of the array to 1 (C99 6.9.2p5).
+        Diag(VD->getLocation(),  diag::warn_tentative_incomplete_array);
+        llvm::APInt One(Context.getTypeSize(Context.getSizeType()), 
+                        true);
+        QualType T 
+          = Context.getConstantArrayType(ArrayT->getElementType(),
+                                         One, ArrayType::Normal, 0);
+        VD->setType(T);
       }
-    }
+    } else if (RequireCompleteType(VD->getLocation(), VD->getType(), 
+                                   diag::err_tentative_def_incomplete_type))
+      VD->setInvalidDecl();
+
+    // Notify the consumer that we've completed a tentative definition.
+    if (!VD->isInvalidDecl())
+      Consumer.CompleteTentativeDefinition(VD);
+
   }
 }