From 5f0929577b652b74fc0caab08b5beb5563c32e50 Mon Sep 17 00:00:00 2001
From: David Blaikie <dblaikie@gmail.com>
Date: Thu, 9 Jan 2014 05:08:28 +0000
Subject: Prototype of skeleton type units for fission

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198851 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 22 +++++++++++++++++++---
 lib/CodeGen/AsmPrinter/DwarfDebug.h   |  4 ++++
 lib/CodeGen/AsmPrinter/DwarfUnit.cpp  |  4 +++-
 3 files changed, 26 insertions(+), 4 deletions(-)

(limited to 'lib/CodeGen')

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 247cd04eac..690ae37674 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2976,6 +2976,21 @@ DwarfCompileUnit *DwarfDebug::constructSkeletonCU(const DwarfCompileUnit *CU) {
   return NewCU;
 }
 
+// This DIE has the following attributes: DW_AT_comp_dir, DW_AT_dwo_name,
+// DW_AT_addr_base.
+DwarfTypeUnit *DwarfDebug::constructSkeletonTU(const DwarfTypeUnit *TU) {
+
+  DIE *Die = new DIE(dwarf::DW_TAG_type_unit);
+  DwarfTypeUnit *NewTU = new DwarfTypeUnit(
+      TU->getUniqueID(), Die, TU->getCUNode(), Asm, this, &SkeletonHolder);
+  NewTU->setTypeSignature(TU->getTypeSignature());
+  NewTU->initSection(
+      Asm->getObjFileLowering().getDwarfTypesSection(TU->getTypeSignature()));
+
+  initSkeletonUnit(TU, Die, NewTU);
+  return NewTU;
+}
+
 // Emit the .debug_info.dwo section for separated dwarf. This contains the
 // compile units that would normally be in debug_info.
 void DwarfDebug::emitDebugInfoDWO() {
@@ -3018,8 +3033,6 @@ void DwarfDebug::addDwarfTypeUnitType(DICompileUnit CUNode,
     NewTU->addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2,
                    CUNode.getLanguage());
 
-    DIE *Die = NewTU->createTypeDIE(CTy);
-
     MD5 Hash;
     Hash.update(Identifier);
     // ... take the least significant 8 bytes and return those. Our MD5
@@ -3029,7 +3042,10 @@ void DwarfDebug::addDwarfTypeUnitType(DICompileUnit CUNode,
     Hash.final(Result);
     uint64_t Signature = *reinterpret_cast<support::ulittle64_t *>(Result + 8);
     NewTU->setTypeSignature(Signature);
-    NewTU->setType(Die);
+    if (useSplitDwarf())
+      NewTU->setSkeleton(constructSkeletonTU(NewTU));
+
+    NewTU->setType(NewTU->createTypeDIE(CTy));
 
     NewTU->initSection(
         useSplitDwarf()
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 0c00c1be36..5a21106055 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -596,6 +596,10 @@ class DwarfDebug : public AsmPrinterHandler {
   /// section.
   DwarfCompileUnit *constructSkeletonCU(const DwarfCompileUnit *CU);
 
+  /// \brief Construct the split debug info compile unit for the debug info
+  /// section.
+  DwarfTypeUnit *constructSkeletonTU(const DwarfTypeUnit *TU);
+
   /// \brief Emit the debug info dwo section.
   void emitDebugInfoDWO();
 
diff --git a/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index b066c95fe9..7cf66954e4 100644
--- a/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1987,7 +1987,9 @@ void DwarfTypeUnit::emitHeader(const MCSection *ASection,
   Asm->OutStreamer.AddComment("Type Signature");
   Asm->OutStreamer.EmitIntValue(TypeSignature, sizeof(TypeSignature));
   Asm->OutStreamer.AddComment("Type DIE Offset");
-  Asm->OutStreamer.EmitIntValue(Ty->getOffset(), sizeof(Ty->getOffset()));
+  // In a skeleton type unit there is no type DIE so emit a zero offset.
+  Asm->OutStreamer.EmitIntValue(Ty ? Ty->getOffset() : 0,
+                                sizeof(Ty->getOffset()));
 }
 
 void DwarfTypeUnit::initSection(const MCSection *Section) {
-- 
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