Revert "Revert "Debug Info: Using declarations/DW_TAG_imported_declaration of variables, types, and functions.""

This reverts commit r181947 (git d2990ce56a16050cac0d7937ec9919ff54c6df62 )

This addresses one of the two issues identified in r181947, ensuring
that types imported via using declarations only result in a declaration
being emitted for the type, not a definition. The second issue (emitting
using declarations that are unused) is hopefully an acceptable increase
as the real fix for this would be a bit difficult (probably at best we
could record which using directives were involved in lookups - but may
not have been the result of the lookup).

This also ensures that DW_TAG_imported_declarations (& directives) are
not emitted in line-tables-only mode as well as ensuring that typedefs
only require/emit declarations (rather than definitions) for referenced
types.

llvm-svn: 182231

1 files changed, 5 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index eb2b0e7..ce7a13d 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -72,14 +72,13 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
   case Decl::Block:
   case Decl::Captured:
   case Decl::ClassScopeFunctionSpecialization:
+  case Decl::UsingShadow:
     llvm_unreachable("Declaration should not be in declstmts!");
   case Decl::Function:  // void X();
   case Decl::Record:    // struct/union/class X;
   case Decl::Enum:      // enum X;
   case Decl::EnumConstant: // enum ? { X = ? }
   case Decl::CXXRecord: // struct/union/class X; [C++]
-  case Decl::Using:          // using X; [C++]
-  case Decl::UsingShadow:
   case Decl::NamespaceAlias:
   case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
   case Decl::Label:        // __label__ x;
@@ -89,6 +88,10 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
     // None of these decls require codegen support.
     return;
 
+  case Decl::Using:          // using X; [C++]
+    if (CGDebugInfo *DI = getDebugInfo())
+        DI->EmitUsingDecl(cast<UsingDecl>(D));
+    return;
   case Decl::UsingDirective: // using namespace X; [C++]
     if (CGDebugInfo *DI = getDebugInfo())
       DI->EmitUsingDirective(cast<UsingDirectiveDecl>(D));