Use the DWARF form DW_FORM_sec_offset or DW_FORM_data4 depending on the Dwarf version being generated

[keith.walker.arm]

Summary

In Dwarf 3 (and Dwarf 2) attributes whose value are offsets into a section use the form DW_FORM_data4 whilst in Dwarf 4 and later they use the form DW_FORM_sec_offset.

This patch updates the places where such attributes are generated to use the appropriate form depending on the Dwarf version. The DIE entries affected have the following tags:
DW_AT_stmt_list, DW_AT_ranges, DW_AT_location, DW_AT_GNU_pubnames, DW_AT_GNU_pubtypes, DW_AT_GNU_addr_base, DW_AT_GNU_ranges_base

It also adds a hidden command line option "--dwarf-version=<uint>" to llc which allows the version of Dwarf to be generated to override what is specified in the metadata; this makes it possible to update existing tests to check the debugging information generated for both Dwarf 4 (the default) and Dwarf 3 using the same metadata.

[echristo]

LGTM. Do you need someone to commit for you?

[probinson]

+; RUN: llc -split-dwarf=Enable -O0 %s -mtriple=x86_64-unknown-linux-gnu -filetype=obj -o %t -dwarf-version=3

This seems weird, fission with DWARF 3... but of course 4 doesn't
have it either, so it's no less weird than what we have today.

It's good to have the forms more consistent with the target version
but eventually we might want to be more picky about mix-n-match.
--paulr

-----Original Message-----
From: [e-mail] [mailto:llvm-commits-
[e-mail]] On Behalf Of Keith Walker
Sent: Thursday, November 14, 2013 8:29 AM
To: [e-mail]; [e-mail]
Cc: [e-mail]
Subject: [PATCH] Use the DWARF form DW_FORM_sec_offset or DW_FORM_data4
depending on the Dwarf version being generated

Hi echristo,

In Dwarf 3 (and Dwarf 2) attributes whose value are offsets into a
section use the form DW_FORM_data4 whilst in Dwarf 4 and later they use
the form DW_FORM_sec_offset.

This patch updates the places where such attributes are generated to use
the appropriate form depending on the Dwarf version. The DIE entries
affected have the following tags:
DW_AT_stmt_list, DW_AT_ranges, DW_AT_location, DW_AT_GNU_pubnames,
DW_AT_GNU_pubtypes, DW_AT_GNU_addr_base, DW_AT_GNU_ranges_base

It also adds a hidden command line option "--dwarf-version=<uint>" to
llc which allows the version of Dwarf to be generated to override what
is specified in the metadata; this makes it possible to update existing
tests to check the debugging information generated for both Dwarf 4 (the
default) and Dwarf 3 using the same metadata.

http://llvm-reviews.chandlerc.com/D2180

Files:

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
lib/CodeGen/AsmPrinter/DIE.cpp
lib/CodeGen/AsmPrinter/DwarfDebug.cpp
test/DebugInfo/X86/op_deref.ll
test/DebugInfo/X86/block-capture.ll
test/DebugInfo/X86/DW_AT_stmt_list_sec_offset.ll
test/DebugInfo/X86/gnu-public-names.ll
test/DebugInfo/X86/fission-cu.ll
test/DebugInfo/X86/stmt-list-multiple-compile-units.ll

[keith.walker.arm]

Updated to remove DWARF 3 checks in fission test.

Eric if there are no further issues with this patch could you please commit it on my behalf.

[echristo]

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

234

I do apologize for the lateness of this comment, but rather than bringing this into addLabel I'd prefer we have a "getSectionOffset()" function that will return the proper form that can be used at the call site. Either that or make these function something like "addSectionOffset". Probably prefer the latter, but I'd want that patch to be more uniform across all of the additions.

Make sense? That possible in the time you have?

[keith.walker.arm]

From: Eric Christopher [mailto:[e-mail]]
Comment at: lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:234
@@ +233,3 @@
+ const MCSymbol *Label) {
+ if (DD->getDwarfVersion() >= 4)

+ addLabel(Die, Attribute, dwarf::DW_FORM_sec_offset, Label);

I do apologize for the lateness of this comment, but rather than bringing this
into addLabel I'd prefer we have a "getSectionOffset()" function that will return
the proper form that can be used at the call site. Either that or make these
function something like "addSectionOffset". Probably prefer the latter, but I'd
want that patch to be more uniform across all of the additions.

Make sense? That possible in the time you have?

I have updated the patch such that methods that use DW_FORM_sec_offset/DW_FORM_data4 are renames as follows:

addLabel() -> addSectionLabel()
addOffset() -> addSectionOffset()
addDelta() -> addSectionDelta()

Hopefully these changes are along the lines that make the usage clearer.

[I am on vacation this week so I am also bit slow responding :-) ]

[echristo]

I've gone ahead and applied this thusly (slightly modified):

M test/DebugInfo/X86/DW_AT_stmt_list_sec_offset.ll
M test/DebugInfo/X86/gnu-public-names.ll
M test/DebugInfo/X86/stmt-list-multiple-compile-units.ll
M test/DebugInfo/X86/op_deref.ll
M test/DebugInfo/X86/block-capture.ll
M lib/CodeGen/AsmPrinter/DIE.cpp
M lib/CodeGen/AsmPrinter/DwarfDebug.cpp
M lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
M lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
r195391 = 9e22df523d65f5200399bfe2dcdeeb900f75a054 (refs/remotes/origin/master)

FWIW llvm-dwarfdump does support dumping some locations but you'd have
to look at the actual debug_loc section to see if the right one
exists. Probably just need to fix the relocation handling and get the
addend in the relocation for DW_AT_location. It would be nice if that
was fixed for sure.

-eric

[echristo]

According to the comments I committed this.

lib/CodeGen/AsmPrinter/DIE.cpp

 void DIEDelta::EmitValue(AsmPrinter *AP, dwarf::Form Form) const {
   AP->EmitLabelDifference(LabelHi, LabelLo, SizeOf(AP, Form));
 }
 
 /// SizeOf - Determine size of delta value in bytes.
 ///
 unsigned DIEDelta::SizeOf(AsmPrinter *AP, dwarf::Form Form) const {
   if (Form == dwarf::DW_FORM_data4) return 4;
+  if (Form == dwarf::DW_FORM_sec_offset) return 4;
   if (Form == dwarf::DW_FORM_strp) return 4;
   return AP->getDataLayout().getPointerSize();
 }
 
 #ifndef NDEBUG
 void DIEDelta::print(raw_ostream &O) const {
   O << "Del: " << LabelHi->getName() << "-" << LabelLo->getName();
 }

lib/CodeGen/AsmPrinter/DwarfCompileUnit.h

public:
 
   /// addLabel - Add a Dwarf label attribute data and value.
   ///
   void addLabel(DIE *Die, dwarf::Attribute Attribute, dwarf::Form Form,
                 const MCSymbol *Label);
 
   void addLabel(DIEBlock *Die, dwarf::Form Form, const MCSymbol *Label);
 
+  /// addLabel - Add a Dwarf label attribute data and value.
+  ///
+  void addLabel(DIE *Die, dwarf::Attribute Attribute, const MCSymbol *Label);
+
+  /// addOffset - Add an offset into a section attribute data and value.
+  ///
+  void addOffset(DIE *Die, dwarf::Attribute Attribute, uint64_t Integer);
+
   /// addLabelAddress - Add a dwarf label attribute data and value using
   /// either DW_FORM_addr or DW_FORM_GNU_addr_index.
   ///
   void addLabelAddress(DIE *Die, dwarf::Attribute Attribute, MCSymbol *Label);
 
   /// addOpAddress - Add a dwarf op address data and value using the
   /// form given and an op of either DW_FORM_addr or DW_FORM_GNU_addr_index.
   ///
   void addOpAddress(DIEBlock *Die, const MCSymbol *Label);
 
   /// addDelta - Add a label delta attribute data and value.
   ///
-  void addDelta(DIE *Die, dwarf::Attribute Attribute, dwarf::Form Form, const MCSymbol *Hi,
+  void addDelta(DIE *Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
                 const MCSymbol *Lo);
 
   /// addDIEEntry - Add a DIE attribute data and value.
   ///
   void addDIEEntry(DIE *Die, dwarf::Attribute Attribute, DIE *Entry);
 
   /// addDIEEntry - Add a DIE attribute data and value.
   ///

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

void CompileUnit::addLabel(DIE *Die, dwarf::Attribute Attribute,
   Die->addValue(Attribute, Form, Value);
 }
 
 void CompileUnit::addLabel(DIEBlock *Die, dwarf::Form Form,
                            const MCSymbol *Label) {
   addLabel(Die, (dwarf::Attribute)0, Form, Label);
 }
 
+/// addLabel - Add a Dwarf label attribute data and value.
+///
+void CompileUnit::addLabel(DIE *Die, dwarf::Attribute Attribute,
+                                  const MCSymbol *Label) {
+  if (DD->getDwarfVersion() >= 4)
+    addLabel(Die, Attribute, dwarf::DW_FORM_sec_offset, Label);
+  else
+    addLabel(Die, Attribute, dwarf::DW_FORM_data4, Label);
+}
+
+/// addOffset - Add an offset into a section attribute data and value.
+///
+void CompileUnit::addOffset(DIE *Die, dwarf::Attribute Attribute,
+                                   uint64_t Integer) {
+  if (DD->getDwarfVersion() >= 4)
+    addUInt(Die, Attribute, dwarf::DW_FORM_sec_offset, Integer);
+  else
+    addUInt(Die, Attribute, dwarf::DW_FORM_data4, Integer);
+}
+
 /// addLabelAddress - Add a dwarf label attribute data and value using
 /// DW_FORM_addr or DW_FORM_GNU_addr_index.
 ///
 void CompileUnit::addLabelAddress(DIE *Die, dwarf::Attribute Attribute,
                                   MCSymbol *Label) {
   if (Label)
     DD->addArangeLabel(SymbolCU(this, Label));
 
if (!DD->useSplitDwarf()) {
     addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_addr_index);
     addUInt(Die, dwarf::DW_FORM_GNU_addr_index, DU->getAddrPoolIndex(Sym));
   }
 }
 
 /// addDelta - Add a label delta attribute data and value.
 ///
 void CompileUnit::addDelta(DIE *Die, dwarf::Attribute Attribute,
-                           dwarf::Form Form, const MCSymbol *Hi,
-                           const MCSymbol *Lo) {
+                           const MCSymbol *Hi, const MCSymbol *Lo) {
   DIEValue *Value = new (DIEValueAllocator) DIEDelta(Hi, Lo);
-  Die->addValue(Attribute, Form, Value);
+  if (DD->getDwarfVersion() >= 4)
+    Die->addValue(Attribute, dwarf::DW_FORM_sec_offset, Value);
+  else
+    Die->addValue(Attribute, dwarf::DW_FORM_data4, Value);
 }
 
 /// addDIEEntry - Add a DIE attribute data and value.
 ///
 void CompileUnit::addDIEEntry(DIE *Die, dwarf::Attribute Attribute,
                               DIE *Entry) {
   addDIEEntry(Die, Attribute, createDIEEntry(Entry));
 }
if (isScopeAbstract) {
     return VariableDie;
   }
 
   // Add variable address.
 
   unsigned Offset = DV.getDotDebugLocOffset();
   if (Offset != ~0U) {
     addLabel(VariableDie, dwarf::DW_AT_location,
-             DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
-                                        : dwarf::DW_FORM_data4,
              Asm->GetTempSymbol("debug_loc", Offset));
     DV.setDIE(VariableDie);
     return VariableDie;
   }
 
   // Check if variable is described by a DBG_VALUE instruction.
   if (const MachineInstr *DVInsn = DV.getMInsn()) {
     assert(DVInsn->getNumOperands() == 3);

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

 static cl::opt<DefaultOnOff>
 DwarfPubSections("generate-dwarf-pub-sections", cl::Hidden,
                  cl::desc("Generate DWARF pubnames and pubtypes sections"),
                  cl::values(clEnumVal(Default, "Default for platform"),
                             clEnumVal(Enable, "Enabled"),
                             clEnumVal(Disable, "Disabled"), clEnumValEnd),
                  cl::init(Default));
 
+static cl::opt<unsigned>
+DwarfVersionNumber("dwarf-version", cl::Hidden,
+                   cl::desc("Generate DWARF for dwarf version."),
+                   cl::init(0));
+
 static const char *const DWARFGroupName = "DWARF Emission";
 static const char *const DbgTimerName = "DWARF Debug Writer";
 
 //===----------------------------------------------------------------------===//
 
 // Configuration values for initial hash set sizes (log2).
 //
 static const unsigned InitAbbreviationsSetSize = 9; // log2(512)

 /// Return Dwarf Version by checking module flags.
 static unsigned getDwarfVersionFromModule(const Module *M) {
   Value *Val = M->getModuleFlag("Dwarf Version");
   if (!Val)
     return dwarf::DWARF_VERSION;
   return cast<ConstantInt>(Val)->getZExtValue();
 }
 
+/// Return Dwarf Version from command line options, or 0 if no
+/// valid option specified.
+static unsigned getDwarfVersionFromOption() {
+  if (DwarfVersionNumber >= 2 && DwarfVersionNumber <= 4) {
+    return DwarfVersionNumber;
+  }
+  return 0;
+}
+
 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   : Asm(A), MMI(Asm->MMI), FirstCU(0),
     AbbreviationsSet(InitAbbreviationsSetSize),
     SourceIdMap(DIEValueAllocator),
     PrevLabel(NULL), GlobalCUIndexCount(0),
     InfoHolder(A, &AbbreviationsSet, Abbreviations, "info_string",
                DIEValueAllocator),
     SkeletonAbbrevSet(InitAbbreviationsSetSize),
DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   else
     HasSplitDwarf = SplitDwarf == Enable;
 
   if (DwarfPubSections == Default)
     HasDwarfPubSections = !IsDarwin;
   else
     HasDwarfPubSections = DwarfPubSections == Enable;
 
+  DwarfVersion = getDwarfVersionFromOption();
+  if (!DwarfVersion)
     DwarfVersion = getDwarfVersionFromModule(MMI->getModule());
 
   {
     NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
     beginModule();
   }
 }
 
 // Switch to the specified MCSection and emit an assembler
if (Scope->isAbstractScope())
     return ScopeDIE;
 
   const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges();
   // If we have multiple ranges, emit them into the range section.
   if (Ranges.size() > 1) {
     // .debug_range section has not been laid out yet. Emit offset in
     // .debug_range as a uint, size 4, for now. emitDIE will handle
     // DW_AT_ranges appropriately.
-    TheCU->addUInt(ScopeDIE, dwarf::DW_AT_ranges, dwarf::DW_FORM_data4,
+    TheCU->addOffset(ScopeDIE, dwarf::DW_AT_ranges,
                    DebugRangeSymbols.size()
                    * Asm->getDataLayout().getPointerSize());
     for (SmallVectorImpl<InsnRange>::const_iterator RI = Ranges.begin(),
          RE = Ranges.end(); RI != RE; ++RI) {
       DebugRangeSymbols.push_back(getLabelBeforeInsn(RI->first));
       DebugRangeSymbols.push_back(getLabelAfterInsn(RI->second));
     }
 
DIE *DwarfDebug::constructInlinedScopeDIE(CompileUnit *TheCU,
 
   DIE *ScopeDIE = new DIE(dwarf::DW_TAG_inlined_subroutine);
   TheCU->addDIEEntry(ScopeDIE, dwarf::DW_AT_abstract_origin, OriginDIE);
 
   if (Ranges.size() > 1) {
     // .debug_range section has not been laid out yet. Emit offset in
     // .debug_range as a uint, size 4, for now. emitDIE will handle
     // DW_AT_ranges appropriately.
-    TheCU->addUInt(ScopeDIE, dwarf::DW_AT_ranges, dwarf::DW_FORM_data4,
+    TheCU->addOffset(ScopeDIE, dwarf::DW_AT_ranges,
                    DebugRangeSymbols.size()
                    * Asm->getDataLayout().getPointerSize());
     for (SmallVectorImpl<InsnRange>::const_iterator RI = Ranges.begin(),
          RE = Ranges.end(); RI != RE; ++RI) {
       DebugRangeSymbols.push_back(getLabelBeforeInsn(RI->first));
       DebugRangeSymbols.push_back(getLabelAfterInsn(RI->second));
     }
     DebugRangeSymbols.push_back(NULL);
CompileUnit *DwarfDebug::constructCompileUnit(DICompileUnit DIUnit) {
 
   if (!useSplitDwarf()) {
     // DW_AT_stmt_list is a offset of line number information for this
     // compile unit in debug_line section. For split dwarf this is
     // left in the skeleton CU and so not included.
     // The line table entries are not always emitted in assembly, so it
     // is not okay to use line_table_start here.
     if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
-      NewCU->addLabel(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_sec_offset,
+      NewCU->addLabel(Die, dwarf::DW_AT_stmt_list,
                       UseTheFirstCU ? Asm->GetTempSymbol("section_line")
                                     : LineTableStartSym);
     else if (UseTheFirstCU)
-      NewCU->addUInt(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4, 0);
+      NewCU->addOffset(Die, dwarf::DW_AT_stmt_list, 0);
     else
-      NewCU->addDelta(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4,
+      NewCU->addDelta(Die, dwarf::DW_AT_stmt_list,
                       LineTableStartSym, DwarfLineSectionSym);
 
     // If we're using split dwarf the compilation dir is going to be in the
     // skeleton CU and so we don't need to duplicate it here.
     if (!CompilationDir.empty())
       NewCU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
 
     // Flags to let the linker know we have emitted new style pubnames. Only
     // emit it here if we don't have a skeleton CU for split dwarf.
     if (GenerateGnuPubSections) {
       if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
         NewCU->addLabel(Die, dwarf::DW_AT_GNU_pubnames,
-                        dwarf::DW_FORM_sec_offset,
                         Asm->GetTempSymbol("gnu_pubnames",
                                            NewCU->getUniqueID()));
       else
-        NewCU->addDelta(Die, dwarf::DW_AT_GNU_pubnames, dwarf::DW_FORM_data4,
+        NewCU->addDelta(Die, dwarf::DW_AT_GNU_pubnames,
                         Asm->GetTempSymbol("gnu_pubnames",
                                            NewCU->getUniqueID()),
                         DwarfGnuPubNamesSectionSym);
 
       if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
         NewCU->addLabel(Die, dwarf::DW_AT_GNU_pubtypes,
-                        dwarf::DW_FORM_sec_offset,
                         Asm->GetTempSymbol("gnu_pubtypes",
                                            NewCU->getUniqueID()));
       else
-        NewCU->addDelta(Die, dwarf::DW_AT_GNU_pubtypes, dwarf::DW_FORM_data4,
+        NewCU->addDelta(Die, dwarf::DW_AT_GNU_pubtypes,
                         Asm->GetTempSymbol("gnu_pubtypes",
                                            NewCU->getUniqueID()),
                         DwarfGnuPubTypesSectionSym);
     }
   }
 
   if (DIUnit.isOptimized())
     NewCU->addFlag(Die, dwarf::DW_AT_APPLE_optimized);
CompileUnit *NewCU = new CompileUnit(CU->getUniqueID(), Die, CU->getNode(),
                                        Asm, this, &SkeletonHolder);
 
   NewCU->addLocalString(Die, dwarf::DW_AT_GNU_dwo_name,
                         CU->getNode().getSplitDebugFilename());
 
   // Relocate to the beginning of the addr_base section, else 0 for the
   // beginning of the one for this compile unit.
   if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
-    NewCU->addLabel(Die, dwarf::DW_AT_GNU_addr_base, dwarf::DW_FORM_sec_offset,
+    NewCU->addLabel(Die, dwarf::DW_AT_GNU_addr_base,
                     DwarfAddrSectionSym);
   else
-    NewCU->addUInt(Die, dwarf::DW_AT_GNU_addr_base,
-                   dwarf::DW_FORM_sec_offset, 0);
+    NewCU->addOffset(Die, dwarf::DW_AT_GNU_addr_base, 0);
 
   // 2.17.1 requires that we use DW_AT_low_pc for a single entry point
   // into an entity. We're using 0, or a NULL label for this.
   NewCU->addUInt(Die, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
 
   // DW_AT_stmt_list is a offset of line number information for this
   // compile unit in debug_line section.
   // FIXME: Should handle multiple compile units.
   if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
-    NewCU->addLabel(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_sec_offset,
+    NewCU->addLabel(Die, dwarf::DW_AT_stmt_list,
                     DwarfLineSectionSym);
   else
-    NewCU->addUInt(Die, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_sec_offset, 0);
+    NewCU->addOffset(Die, dwarf::DW_AT_stmt_list, 0);
 
   if (!CompilationDir.empty())
     NewCU->addLocalString(Die, dwarf::DW_AT_comp_dir, CompilationDir);
 
   // Flags to let the linker know we have emitted new style pubnames.
   if (GenerateGnuPubSections) {
     if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
-      NewCU->addLabel(Die, dwarf::DW_AT_GNU_pubnames, dwarf::DW_FORM_sec_offset,
+      NewCU->addLabel(Die, dwarf::DW_AT_GNU_pubnames,
                       Asm->GetTempSymbol("gnu_pubnames", NewCU->getUniqueID()));
     else
-      NewCU->addDelta(Die, dwarf::DW_AT_GNU_pubnames, dwarf::DW_FORM_data4,
+      NewCU->addDelta(Die, dwarf::DW_AT_GNU_pubnames,
                       Asm->GetTempSymbol("gnu_pubnames", NewCU->getUniqueID()),
                       DwarfGnuPubNamesSectionSym);
 
     if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
-      NewCU->addLabel(Die, dwarf::DW_AT_GNU_pubtypes, dwarf::DW_FORM_sec_offset,
+      NewCU->addLabel(Die, dwarf::DW_AT_GNU_pubtypes,
                       Asm->GetTempSymbol("gnu_pubtypes", NewCU->getUniqueID()));
     else
-      NewCU->addDelta(Die, dwarf::DW_AT_GNU_pubtypes, dwarf::DW_FORM_data4,
+      NewCU->addDelta(Die, dwarf::DW_AT_GNU_pubtypes,
                       Asm->GetTempSymbol("gnu_pubtypes", NewCU->getUniqueID()),
                       DwarfGnuPubTypesSectionSym);
   }
 
   // Flag if we've emitted any ranges and their location for the compile unit.
   if (DebugRangeSymbols.size()) {
     if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
       NewCU->addLabel(Die, dwarf::DW_AT_GNU_ranges_base,
-                      dwarf::DW_FORM_sec_offset, DwarfDebugRangeSectionSym);
+                DwarfDebugRangeSectionSym);
     else
       NewCU->addUInt(Die, dwarf::DW_AT_GNU_ranges_base, dwarf::DW_FORM_data4,
                      0);
   }
 
   SkeletonHolder.addUnit(NewCU);
   SkeletonCUs.push_back(NewCU);
 

test/DebugInfo/X86/DW_AT_stmt_list_sec_offset.ll

 ; RUN: llc -mtriple=i686-w64-mingw32 -o %t -filetype=obj %s
 ; RUN: llvm-dwarfdump -debug-dump=all %t | FileCheck %s
+; RUN: llc -mtriple=i686-w64-mingw32 -o %t -filetype=obj -dwarf-version=3 %s
+; RUN: llvm-dwarfdump -debug-dump=all %t | FileCheck %s -check-prefix=DWARF3
 
 ; CHECK:     DW_AT_stmt_list [DW_FORM_sec_offset]
+; DWARF3:    DW_AT_stmt_list [DW_FORM_data4]
 ;
 ; generated from:
 ; clang -g -S -emit-llvm test.c -o test.ll
 ; int main()
 ; {
 ;   return 0;
 ; }
 

 !1 = metadata !{metadata !"test.c", metadata !"C:\5CProjects"}
 !2 = metadata !{i32 0}
 !3 = metadata !{metadata !4}
 !4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"main", metadata !"main", metadata !"", i32 1, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 0, i1 false, i32 ()* @main, null, null, metadata !2, i32 2} ; [ DW_TAG_subprogram ] [line 1] [def] [scope 2] [main]
 !5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [C:\Projects/test.c]
 !6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
 !7 = metadata !{metadata !8}
 !8 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
-!9 = metadata !{i32 2, metadata !"Dwarf Version", i32 3}
+!9 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
 !10 = metadata !{i32 3, i32 0, metadata !4, null}

test/DebugInfo/X86/block-capture.ll

 ; RUN: llc -mtriple=x86_64-apple-darwin %s -o %t -filetype=obj
 ; RUN: llvm-dwarfdump -debug-dump=info %t | FileCheck %s
+; RUN: llc -mtriple=x86_64-apple-darwin %s -o %t -filetype=obj -dwarf-version=3
+; RUN: llvm-dwarfdump -debug-dump=info %t | FileCheck %s -check-prefix=DWARF3
 
 ; Checks that we emit debug info for the block variable declare.
 ; CHECK: DW_TAG_subprogram [3]
 ; CHECK: DW_TAG_variable [5]
 ; CHECK: DW_AT_name [DW_FORM_strp]     ( .debug_str[{{.*}}] = "block")
 ; CHECK: DW_AT_location [DW_FORM_sec_offset]        ({{.*}})
 
+; DWARF3: DW_TAG_subprogram [3]
+; DWARF3: DW_TAG_variable [5]
+; DWARF3: DW_AT_name [DW_FORM_strp]     ( .debug_str[{{.*}}] = "block")
+; DWARF3: DW_AT_location [DW_FORM_data4]        ({{.*}})
+
 %struct.__block_descriptor = type { i64, i64 }
 %struct.__block_literal_generic = type { i8*, i32, i32, i8*, %struct.__block_descriptor* }
 
 declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
 
 define hidden void @__foo_block_invoke_0(i8* %.block_descriptor) uwtable ssp {
 entry:
   %exn.slot = alloca i8*

test/DebugInfo/X86/gnu-public-names.ll

 ; RUN: llc -mtriple=x86_64-pc-linux-gnu -generate-gnu-dwarf-pub-sections < %s | FileCheck -check-prefix=ASM %s
 ; RUN: llc -mtriple=x86_64-pc-linux-gnu -generate-gnu-dwarf-pub-sections -filetype=obj < %s | llvm-dwarfdump - | FileCheck %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -generate-gnu-dwarf-pub-sections -filetype=obj -dwarf-version=3 < %s | llvm-dwarfdump - | FileCheck %s -check-prefix=DWARF3
 ; ModuleID = 'dwarf-public-names.cpp'
 ;
 ; Generated from:
 ;
 ; struct C {
 ;   void member_function();
 ;   static int static_member_function();
 ;   static int static_member_variable;

 
 
 ; CHECK-LABEL: debug_gnu_pubtypes contents:
 ; CHECK: Offset     Linkage  Kind     Name
 ; CHECK-DAG:  [[C]] EXTERNAL TYPE     "C"
 ; CHECK-DAG:  [[D]] EXTERNAL TYPE     "ns::D"
 ; CHECK-DAG:  [[INT]] STATIC   TYPE     "int"
 
+; DWARF3: .debug_info contents:
+; DWARF3: DW_AT_GNU_pubnames [DW_FORM_data4]   (0x00000000)
+; DWARF3: DW_AT_GNU_pubtypes [DW_FORM_data4]   (0x00000000)
+
+; DWARF3: [[C:[0-9a-f]+]]: DW_TAG_structure_type
+; DWARF3-NEXT: DW_AT_name {{.*}} "C"
+
+; DWARF3: [[STATIC_MEM_DECL:[0-9a-f]+]]: DW_TAG_member
+; DWARF3-NEXT: DW_AT_name {{.*}} "static_member_variable"
+
+; DWARF3: [[MEM_FUNC_DECL:[0-9a-f]+]]: DW_TAG_subprogram
+; DWARF3-NEXT: DW_AT_MIPS_linkage_name
+; DWARF3-NEXT: DW_AT_name {{.*}} "member_function"
+
+; DWARF3: [[STATIC_MEM_FUNC_DECL:[0-9a-f]+]]: DW_TAG_subprogram
+; DWARF3-NEXT: DW_AT_MIPS_linkage_name
+; DWARF3-NEXT: DW_AT_name {{.*}} "static_member_function"
+
+; DWARF3: [[INT:[0-9a-f]+]]: DW_TAG_base_type
+; DWARF3-NEXT: DW_AT_name {{.*}} "int"
+
+; DWARF3: [[STATIC_MEM_VAR:[0-9a-f]+]]: DW_TAG_variable
+; DWARF3-NEXT: DW_AT_specification {{.*}}[[STATIC_MEM_DECL]]
+
+; DWARF3: [[GLOB_VAR:[0-9a-f]+]]: DW_TAG_variable
+; DWARF3-NEXT: DW_AT_name {{.*}} "global_variable"
+
+; DWARF3: [[NS:[0-9a-f]+]]: DW_TAG_namespace
+; DWARF3-NEXT: DW_AT_name {{.*}} "ns"
+
+; DWARF3: [[GLOB_NS_VAR_DECL:[0-9a-f]+]]: DW_TAG_variable
+; DWARF3-NEXT: DW_AT_name {{.*}} "global_namespace_variable"
+
+; DWARF3: [[D_VAR_DECL:[0-9a-f]+]]: DW_TAG_variable
+; DWARF3-NEXT: DW_AT_name {{.*}} "d"
+
+; DWARF3: [[D:[0-9a-f]+]]: DW_TAG_structure_type
+; DWARF3-NEXT: DW_AT_name {{.*}} "D"
+
+; DWARF3: [[GLOB_NS_FUNC:[0-9a-f]+]]: DW_TAG_subprogram
+; DWARF3-NEXT: DW_AT_MIPS_linkage_name
+; DWARF3-NEXT: DW_AT_name {{.*}} "global_namespace_function"
+
+; DWARF3: [[GLOB_NS_VAR:[0-9a-f]+]]: DW_TAG_variable
+; DWARF3-NEXT: DW_AT_specification {{.*}}[[GLOB_NS_VAR_DECL]]
+
+; DWARF3: [[D_VAR:[0-9a-f]+]]: DW_TAG_variable
+; DWARF3-NEXT: DW_AT_specification {{.*}}[[D_VAR_DECL]]
+
+; DWARF3: [[MEM_FUNC:[0-9a-f]+]]: DW_TAG_subprogram
+; DWARF3-NEXT: DW_AT_specification {{.*}}[[MEM_FUNC_DECL]]
+
+; DWARF3: [[STATIC_MEM_FUNC:[0-9a-f]+]]: DW_TAG_subprogram
+; DWARF3-NEXT: DW_AT_specification {{.*}}[[STATIC_MEM_FUNC_DECL]]
+
+; DWARF3: [[GLOBAL_FUNC:[0-9a-f]+]]: DW_TAG_subprogram
+; DWARF3-NEXT: DW_AT_MIPS_linkage_name
+; DWARF3-NEXT: DW_AT_name {{.*}} "global_function"
+
+; DWARF3-LABEL: .debug_gnu_pubnames contents:
+; DWARF3-NEXT: length = 0x000000e7 version = 0x0002 unit_offset = 0x00000000 unit_size = 0x0000018b
+; DWARF3-NEXT: Offset     Linkage  Kind     Name
+; DWARF3-DAG:  [[GLOBAL_FUNC]] EXTERNAL FUNCTION "global_function"
+; DWARF3-DAG:  [[NS]] EXTERNAL TYPE     "ns"
+; DWARF3-DAG:  [[MEM_FUNC]] EXTERNAL FUNCTION "C::member_function"
+; DWARF3-DAG:  [[GLOB_VAR]] EXTERNAL VARIABLE "global_variable"
+; DWARF3-DAG:  [[GLOB_NS_VAR]] EXTERNAL VARIABLE "ns::global_namespace_variable"
+; DWARF3-DAG:  [[GLOB_NS_FUNC]] EXTERNAL FUNCTION "ns::global_namespace_function"
+; DWARF3-DAG:  [[D_VAR]] EXTERNAL VARIABLE "ns::d"
+; DWARF3-DAG:  [[STATIC_MEM_VAR]] EXTERNAL VARIABLE "C::static_member_variable"
+; DWARF3-DAG:  [[STATIC_MEM_FUNC]] EXTERNAL FUNCTION "C::static_member_function"
+
+
+; DWARF3-LABEL: debug_gnu_pubtypes contents:
+; DWARF3: Offset     Linkage  Kind     Name
+; DWARF3-DAG:  [[C]] EXTERNAL TYPE     "C"
+; DWARF3-DAG:  [[D]] EXTERNAL TYPE     "ns::D"
+; DWARF3-DAG:  [[INT]] STATIC   TYPE     "int"
+
 %struct.C = type { i8 }
 %"struct.ns::D" = type { i32 }
 
 @_ZN1C22static_member_variableE = global i32 0, align 4
 @global_variable = global %struct.C zeroinitializer, align 1
 @_ZN2ns25global_namespace_variableE = global i32 1, align 4
 @_ZN2ns1dE = global %"struct.ns::D" zeroinitializer, align 4
 

test/DebugInfo/X86/op_deref.ll

 ; RUN: llc -O0 -mtriple=x86_64-apple-darwin %s -o %t -filetype=obj
 ; RUN: llvm-dwarfdump -debug-dump=info %t | FileCheck %s -check-prefix=DW-CHECK
+; RUN: llc -O0 -mtriple=x86_64-apple-darwin %s -o %t -filetype=obj -dwarf-version=3
+; RUN: llvm-dwarfdump -debug-dump=info %t | FileCheck %s -check-prefix=DWARF3
 
 ; DW-CHECK: DW_AT_name [DW_FORM_strp]  ( .debug_str[0x00000067] = "vla")
 ; FIXME: The location here needs to be fixed, but llvm-dwarfdump doesn't handle
 ; DW_AT_location lists yet.
 ; DW-CHECK: DW_AT_location [DW_FORM_sec_offset]                      (0x00000000)
 
+; DWARF3: DW_AT_name [DW_FORM_strp]  ( .debug_str[0x00000067] = "vla")
+; FIXME: The location here needs to be fixed, but llvm-dwarfdump doesn't handle
+; DW_AT_location lists yet.
+; DWARF3: DW_AT_location [DW_FORM_data4]                      (0x00000000)
+
 ; Unfortunately llvm-dwarfdump can't unparse a list of DW_AT_locations
 ; right now, so we check the asm output:
 ; RUN: llc -O0 -mtriple=x86_64-apple-darwin %s -o - -filetype=asm | FileCheck %s -check-prefix=ASM-CHECK
 ; vla should have a register-indirect address at one point.
 ; ASM-CHECK: DEBUG_VALUE: vla <- RCX
 ; ASM-CHECK: DW_OP_breg2
 
 define void @testVLAwithSize(i32 %s) nounwind uwtable ssp {

test/DebugInfo/X86/stmt-list-multiple-compile-units.ll

 ; RUN: llc -O0 %s -mtriple=x86_64-apple-darwin -filetype=obj -o %t
 ; RUN: llvm-dwarfdump %t | FileCheck %s
+; RUN: llc -O0 %s -mtriple=x86_64-apple-darwin -filetype=obj -o %t -dwarf-version=3
+; RUN: llvm-dwarfdump %t | FileCheck %s -check-prefix=DWARF3
 ; RUN: llc < %s -O0 -mtriple=x86_64-apple-macosx10.7 | FileCheck %s -check-prefix=ASM
 
 ; rdar://13067005
 ; CHECK: .debug_info contents:
 ; CHECK: DW_TAG_compile_unit
 ; CHECK: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
-; CHECK: DW_AT_stmt_list [DW_FORM_data4]   (0x00000000)
+; CHECK: DW_AT_stmt_list [DW_FORM_sec_offset]   (0x00000000)
 
 ; CHECK: DW_TAG_compile_unit
 ; CHECK: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
-; CHECK: DW_AT_stmt_list [DW_FORM_data4]   (0x0000003c)
+; CHECK: DW_AT_stmt_list [DW_FORM_sec_offset]   (0x0000003c)
 
 ; CHECK: .debug_line contents:
 ; CHECK-NEXT: Line table prologue:
 ; CHECK-NEXT: total_length: 0x00000038
 ; CHECK: file_names[  1]    0 0x00000000 0x00000000 simple.c
 ; CHECK: Line table prologue:
 ; CHECK-NEXT: total_length: 0x00000039
 ; CHECK: file_names[  1]    0 0x00000000 0x00000000 simple2.c
 ; CHECK-NOT: file_names
 
+; DWARF3: .debug_info contents:
+; DWARF3: DW_TAG_compile_unit
+; DWARF3: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
+; DWARF3: DW_AT_stmt_list [DW_FORM_data4]   (0x00000000)
+
+; DWARF3: DW_TAG_compile_unit
+; DWARF3: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
+; DWARF3: DW_AT_stmt_list [DW_FORM_data4]   (0x0000003c)
+
+; DWARF3: .debug_line contents:
+; DWARF3-NEXT: Line table prologue:
+; DWARF3-NEXT: total_length: 0x00000038
+; DWARF3: file_names[  1]    0 0x00000000 0x00000000 simple.c
+; DWARF3: Line table prologue:
+; DWARF3-NEXT: total_length: 0x00000039
+; DWARF3: file_names[  1]    0 0x00000000 0x00000000 simple2.c
+; DWARF3-NOT: file_names
+
 ; PR15408
 ; ASM: L__DWARF__debug_info_begin0:
 ; ASM: .long   0                       ## DW_AT_stmt_list
 ; ASM: L__DWARF__debug_info_begin1:
 ; ASM: .long   0                       ## DW_AT_stmt_list
 define i32 @test(i32 %a) nounwind uwtable ssp {
 entry:
   %a.addr = alloca i32, align 4