From 04d6d478650503e74d2f7e8337e6c2b381ba1bc7 Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Wed, 14 Sep 2011 23:13:28 +0000
Subject: [PATCH] Add support to emit debug info for C++0x nullptr type.

llvm-svn: 139751
---
 llvm/include/llvm/Analysis/DIBuilder.h        |  3 +++
 llvm/lib/Analysis/DIBuilder.cpp               | 20 +++++++++++++++++++
 llvm/lib/Analysis/DebugInfo.cpp               |  9 ++++++++-
 .../CodeGen/AsmPrinter/DwarfCompileUnit.cpp   | 15 ++++++++++----
 4 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/llvm/include/llvm/Analysis/DIBuilder.h b/llvm/include/llvm/Analysis/DIBuilder.h
index 8a6a58e3ed4c..a29d762b46bc 100644
--- a/llvm/include/llvm/Analysis/DIBuilder.h
+++ b/llvm/include/llvm/Analysis/DIBuilder.h
@@ -97,6 +97,9 @@ namespace llvm {
     /// createEnumerator - Create a single enumerator value.
     DIEnumerator createEnumerator(StringRef Name, uint64_t Val);
 
+    /// createNullPtrType - Create C++0x nullptr type.
+    DIType createNullPtrType(StringRef Name);
+
     /// createBasicType - Create debugging information entry for a basic 
     /// type.
     /// @param Name        Type name.
diff --git a/llvm/lib/Analysis/DIBuilder.cpp b/llvm/lib/Analysis/DIBuilder.cpp
index cce8d9685408..fd56d369a667 100644
--- a/llvm/lib/Analysis/DIBuilder.cpp
+++ b/llvm/lib/Analysis/DIBuilder.cpp
@@ -146,6 +146,26 @@ DIEnumerator DIBuilder::createEnumerator(StringRef Name, uint64_t Val) {
   return DIEnumerator(MDNode::get(VMContext, Elts));
 }
 
+/// createNullPtrType - Create C++0x nullptr type.
+DIType DIBuilder::createNullPtrType(StringRef Name) {
+  assert(!Name.empty() && "Unable to create type without name");
+  // nullptr is encoded in DIBasicType format. Line number, filename,
+  // ,size, alignment, offset and flags are always empty here.
+  Value *Elts[] = {
+    GetTagConstant(VMContext, dwarf::DW_TAG_unspecified_type),
+    NULL, //TheCU,
+    MDString::get(VMContext, Name),
+    NULL, // Filename
+    ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Line
+    ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Size
+    ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Align
+    ConstantInt::get(Type::getInt64Ty(VMContext), 0), // Offset
+    ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Flags;
+    ConstantInt::get(Type::getInt32Ty(VMContext), 0), // Encoding
+  };
+  return DIType(MDNode::get(VMContext, Elts));
+}
+
 /// createBasicType - Create debugging information entry for a basic
 /// type, e.g 'char'.
 DIType DIBuilder::createBasicType(StringRef Name, uint64_t SizeInBits,
diff --git a/llvm/lib/Analysis/DebugInfo.cpp b/llvm/lib/Analysis/DebugInfo.cpp
index a3dea40d87b1..aeb039ce71c1 100644
--- a/llvm/lib/Analysis/DebugInfo.cpp
+++ b/llvm/lib/Analysis/DebugInfo.cpp
@@ -130,7 +130,14 @@ MDNode *DIVariable::getInlinedAt() const {
 /// isBasicType - Return true if the specified tag is legal for
 /// DIBasicType.
 bool DIDescriptor::isBasicType() const {
-  return DbgNode && getTag() == dwarf::DW_TAG_base_type;
+  if (!DbgNode) return false;
+  switch (getTag()) {
+  case dwarf::DW_TAG_base_type:
+  case dwarf::DW_TAG_unspecified_type:
+    return true;
+  default:
+    return false;
+  }
 }
 
 /// isDerivedType - Return true if the specified tag is legal for DIDerivedType.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index d6be3f3f5b70..33a065d58430 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -658,13 +658,20 @@ void CompileUnit::addPubTypes(DISubprogram SP) {
 void CompileUnit::constructTypeDIE(DIE &Buffer, DIBasicType BTy) {
   // Get core information.
   StringRef Name = BTy.getName();
-  Buffer.setTag(dwarf::DW_TAG_base_type);
-  addUInt(&Buffer, dwarf::DW_AT_encoding,  dwarf::DW_FORM_data1,
-          BTy.getEncoding());
-
   // Add name if not anonymous or intermediate type.
   if (!Name.empty())
     addString(&Buffer, dwarf::DW_AT_name, dwarf::DW_FORM_string, Name);
+
+  if (BTy.getTag() == dwarf::DW_TAG_unspecified_type) {
+    Buffer.setTag(dwarf::DW_TAG_unspecified_type);
+    // Unspecified types has only name, nothing else.
+    return;
+  }
+
+  Buffer.setTag(dwarf::DW_TAG_base_type);
+  addUInt(&Buffer, dwarf::DW_AT_encoding,  dwarf::DW_FORM_data1,
+	  BTy.getEncoding());
+
   uint64_t Size = BTy.getSizeInBits() >> 3;
   addUInt(&Buffer, dwarf::DW_AT_byte_size, 0, Size);
 }