From 9018ef709e798ad49957fc808744aee4ecf52b5f Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Fri, 5 Oct 2012 01:49:33 +0000
Subject: [PATCH] Make sure to generate the right kind of MDNode for enum
 forward declarations. PR14029, clang part.

llvm-svn: 165289
---
 clang/lib/CodeGen/CGDebugInfo.cpp               | 31 ++++++++++++++++++-------
 clang/test/CodeGenCXX/debug-info-enum-class.cpp | 16 ++++++++++++-
 clang/test/CodeGenObjC/debug-info-fwddecl.m     |  2 +-
 3 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 9a0bcd5..16115c1 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -1598,9 +1598,29 @@ llvm::DIType CGDebugInfo::CreateType(const AtomicType *Ty,
 
 /// CreateEnumType - get enumeration type.
 llvm::DIType CGDebugInfo::CreateEnumType(const EnumDecl *ED) {
-  SmallVector<llvm::Value *, 16> Enumerators;
+  uint64_t Size = 0;
+  uint64_t Align = 0;
+  if (!ED->getTypeForDecl()->isIncompleteType()) {
+    Size = CGM.getContext().getTypeSize(ED->getTypeForDecl());
+    Align = CGM.getContext().getTypeAlign(ED->getTypeForDecl());
+  }
+
+  // If this is just a forward declaration, construct an appropriately
+  // marked node and just return it.
+  if (!ED->getDefinition()) {
+    llvm::DIDescriptor EDContext;
+    EDContext = getContextDescriptor(cast<Decl>(ED->getDeclContext()));
+    llvm::DIFile DefUnit = getOrCreateFile(ED->getLocation());
+    unsigned Line = getLineNumber(ED->getLocation());
+    StringRef EDName = ED->getName();
+    return DBuilder.createForwardDecl(llvm::dwarf::DW_TAG_enumeration_type,
+                                      EDName, EDContext, DefUnit, Line, 0,
+                                      Size, Align);
+  }
 
   // Create DIEnumerator elements for each enumerator.
+  SmallVector<llvm::Value *, 16> Enumerators;
+  ED = ED->getDefinition();
   for (EnumDecl::enumerator_iterator
          Enum = ED->enumerator_begin(), EnumEnd = ED->enumerator_end();
        Enum != EnumEnd; ++Enum) {
@@ -1614,21 +1634,14 @@ llvm::DIType CGDebugInfo::CreateEnumType(const EnumDecl *ED) {
 
   llvm::DIFile DefUnit = getOrCreateFile(ED->getLocation());
   unsigned Line = getLineNumber(ED->getLocation());
-  uint64_t Size = 0;
-  uint64_t Align = 0;
-  if (!ED->getTypeForDecl()->isIncompleteType()) {
-    Size = CGM.getContext().getTypeSize(ED->getTypeForDecl());
-    Align = CGM.getContext().getTypeAlign(ED->getTypeForDecl());
-  }
   llvm::DIDescriptor EnumContext = 
     getContextDescriptor(cast<Decl>(ED->getDeclContext()));
   llvm::DIType ClassTy = ED->isScopedUsingClassTag() ?
     getOrCreateType(ED->getIntegerType(), DefUnit) : llvm::DIType();
-  unsigned Flags = !ED->isCompleteDefinition() ? llvm::DIDescriptor::FlagFwdDecl : 0;
   llvm::DIType DbgTy = 
     DBuilder.createEnumerationType(EnumContext, ED->getName(), DefUnit, Line,
                                    Size, Align, EltArray,
-                                   ClassTy, Flags);
+                                   ClassTy);
   return DbgTy;
 }
 
diff --git a/clang/test/CodeGenCXX/debug-info-enum-class.cpp b/clang/test/CodeGenCXX/debug-info-enum-class.cpp
index 6f88439..fd243ab 100644
--- a/clang/test/CodeGenCXX/debug-info-enum-class.cpp
+++ b/clang/test/CodeGenCXX/debug-info-enum-class.cpp
@@ -12,4 +12,18 @@ D d;
 // CHECK: metadata !{i32 {{.*}}, null, metadata !"A", metadata !4, i32 3, i64 32, i64 32, i32 0, i32 0, metadata !5, metadata !6, i32 0, i32 0} ; [ DW_TAG_enumeration_type ]
 // CHECK: metadata !{i32 {{.*}}, null, metadata !"B", metadata !4, i32 4, i64 64, i64 64, i32 0, i32 0, metadata !9, metadata !10, i32 0, i32 0} ; [ DW_TAG_enumeration_type ]
 // CHECK: metadata !{i32 {{.*}}, null, metadata !"C", metadata !4, i32 5, i64 32, i64 32, i32 0, i32 0, null, metadata !13, i32 0, i32 0} ; [ DW_TAG_enumeration_type ]
-// CHECK: metadata !{i32 {{.*}}, null, metadata !"D", metadata !4, i32 6, i64 16, i64 16, i32 0, i32 4, null, metadata !16, i32 0, i32 0} ; [ DW_TAG_enumeration_type ]
+// CHECK: metadata !{i32 {{.*}}, null, metadata !"D", metadata !4, i32 6, i64 16, i64 16, i32 0, i32 4, null, null, i32 0} ; [ DW_TAG_enumeration_type ]
+
+namespace PR14029 {
+  // Make sure this doesn't crash/assert.
+  template <typename T> struct Test {
+    enum class Tag {
+      test = 0
+    };
+    Test() {
+      auto t = Tag::test;
+    }
+    Tag tag() const { return static_cast<Tag>(1); }
+  };
+  Test<int> t;
+}
diff --git a/clang/test/CodeGenObjC/debug-info-fwddecl.m b/clang/test/CodeGenObjC/debug-info-fwddecl.m
index ebdc5f2..8f2860c 100644
--- a/clang/test/CodeGenObjC/debug-info-fwddecl.m
+++ b/clang/test/CodeGenObjC/debug-info-fwddecl.m
@@ -2,4 +2,4 @@
 @class ForwardObjcClass;
 ForwardObjcClass *ptr = 0;
 
-// CHECK: metadata !{i32 {{.*}}, null, metadata !"ForwardObjcClass", metadata !{{.*}}, i32 2, i32 0, i32 0, i32 0, i32 4, null, null, i32 16} ; [ DW_TAG_structure_type ]
+// CHECK: metadata !{i32 {{.*}}, null, metadata !"ForwardObjcClass", metadata !{{.*}}, i32 2, i64 0, i64 0, i32 0, i32 4, null, null, i32 16} ; [ DW_TAG_structure_type ]
-- 
2.7.4