Module debugging: Defer emitting tag types until their definition

was visited and all decls have been merged.

We only get a single chance to emit the types for virtual classes because
CGDebugInfo::completeRequiredType() categorically doesn't complete them.

llvm-svn: 256962

1 files changed, 16 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp b/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
index b397eb3..f385e53 100644
--- a/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
+++ b/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
@@ -59,8 +59,10 @@ class PCHContainerGenerator : public ASTConsumer {
   struct DebugTypeVisitor : public RecursiveASTVisitor<DebugTypeVisitor> {
     clang::CodeGen::CGDebugInfo &DI;
     ASTContext &Ctx;
-    DebugTypeVisitor(clang::CodeGen::CGDebugInfo &DI, ASTContext &Ctx)
-        : DI(DI), Ctx(Ctx) {}
+    bool SkipTagDecls;
+    DebugTypeVisitor(clang::CodeGen::CGDebugInfo &DI, ASTContext &Ctx,
+                     bool SkipTagDecls)
+        : DI(DI), Ctx(Ctx), SkipTagDecls(SkipTagDecls) {}
 
     /// Determine whether this type can be represented in DWARF.
     static bool CanRepresent(const Type *Ty) {
@@ -75,6 +77,12 @@ class PCHContainerGenerator : public ASTConsumer {
     }
 
     bool VisitTypeDecl(TypeDecl *D) {
+      // TagDecls may be deferred until after all decls have been merged and we
+      // know the complete type. Pure forward declarations will be skipped, but
+      // they don't need to be emitted into the module anyway.
+      if (SkipTagDecls && isa<TagDecl>(D))
+          return true;
+
       QualType QualTy = Ctx.getTypeDeclType(D);
       if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
         DI.getOrCreateStandaloneType(QualTy, D->getLocation());
@@ -165,7 +173,7 @@ public:
     // Collect debug info for all decls in this group.
     for (auto *I : D)
       if (!I->isFromASTFile()) {
-        DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
+        DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx, true);
         DTV.TraverseDecl(I);
       }
     return true;
@@ -179,6 +187,11 @@ public:
     if (Diags.hasErrorOccurred())
       return;
 
+    if (D->isFromASTFile())
+      return;
+
+    DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx, false);
+    DTV.TraverseDecl(D);
     Builder->UpdateCompletedType(D);
   }