Revert "Remove the darwin gdb option, that version of gdb is now dead and the rest of the compatibility should be done on a dwarf-N level."

This reverts commit r189903.

This commit broke the phase 1 buildbot for a while.

http://lab.llvm.org:8013/builders/clang-x86_64-darwin11-nobootstrap-RAincremental/builds/6684

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189913 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -100,7 +100,7 @@ int64_t CompileUnit::getDefaultLowerBound() const {
 
 /// addFlag - Add a flag that is true.
 void CompileUnit::addFlag(DIE *Die, uint16_t Attribute) {
-  if (DD->getDwarfVersion() >= 4)
+  if (!DD->useDarwinGDBCompat())
     Die->addValue(Attribute, dwarf::DW_FORM_flag_present,
                   DIEIntegerOne);
   else
@@ -1242,6 +1242,17 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
   // Add function template parameters.
   addTemplateParams(*SPDie, SP.getTemplateParams());
 
+  // Unfortunately this code needs to stay here instead of below the
+  // AT_specification code in order to work around a bug in older
+  // gdbs that requires the linkage name to resolve multiple template
+  // functions.
+  // TODO: Remove this set of code when we get rid of the old gdb
+  // compatibility.
+  StringRef LinkageName = SP.getLinkageName();
+  if (!LinkageName.empty() && DD->useDarwinGDBCompat())
+    addString(SPDie, dwarf::DW_AT_MIPS_linkage_name,
+              GlobalValue::getRealLinkageName(LinkageName));
+
   // If this DIE is going to refer declaration info using AT_specification
   // then there is no need to add other attributes.
   if (DeclDie) {
@@ -1253,8 +1264,7 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
   }
 
   // Add the linkage name if we have one.
-  StringRef LinkageName = SP.getLinkageName();
-  if (!LinkageName.empty())
+  if (!LinkageName.empty() && !DD->useDarwinGDBCompat())
     addString(SPDie, dwarf::DW_AT_MIPS_linkage_name,
               GlobalValue::getRealLinkageName(LinkageName));
 
@@ -1449,15 +1459,21 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
     } else {
       addBlock(VariableDIE, dwarf::DW_AT_location, 0, Block);
     }
-    // Add the linkage name.
+    // Add linkage name.
     StringRef LinkageName = GV.getLinkageName();
-    if (!LinkageName.empty())
+    if (!LinkageName.empty()) {
       // From DWARF4: DIEs to which DW_AT_linkage_name may apply include:
       // TAG_common_block, TAG_constant, TAG_entry_point, TAG_subprogram and
       // TAG_variable.
       addString(IsStaticMember && VariableSpecDIE ?
                 VariableSpecDIE : VariableDIE, dwarf::DW_AT_MIPS_linkage_name,
                 GlobalValue::getRealLinkageName(LinkageName));
+      // In compatibility mode with older gdbs we put the linkage name on both
+      // the TAG_variable DIE and on the TAG_member DIE.
+      if (IsStaticMember && VariableSpecDIE && DD->useDarwinGDBCompat())
+        addString(VariableDIE, dwarf::DW_AT_MIPS_linkage_name,
+                  GlobalValue::getRealLinkageName(LinkageName));
+    }
   } else if (const ConstantInt *CI =
              dyn_cast_or_null<ConstantInt>(GV.getConstant())) {
     // AT_const_value was added when the static member was created. To avoid

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -84,6 +84,14 @@ DwarfAccelTables("dwarf-accel-tables", cl::Hidden,
                             clEnumVal(Disable, "Disabled"), clEnumValEnd),
                  cl::init(Default));
 
+static cl::opt<DefaultOnOff>
+DarwinGDBCompat("darwin-gdb-compat", cl::Hidden,
+                cl::desc("Compatibility with Darwin gdb."),
+                cl::values(clEnumVal(Default, "Default for platform"),
+                           clEnumVal(Enable, "Enabled"),
+                           clEnumVal(Disable, "Disabled"), clEnumValEnd),
+                cl::init(Default));
+
 static cl::opt<DefaultOnOff>
 SplitDwarf("split-dwarf", cl::Hidden,
            cl::desc("Output prototype dwarf split debug info."),
@@ -198,6 +206,11 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   // and handle split dwarf.
   bool IsDarwin = Triple(A->getTargetTriple()).isOSDarwin();
 
+  if (DarwinGDBCompat == Default)
+    IsDarwinGDBCompat = IsDarwin;
+  else
+    IsDarwinGDBCompat = DarwinGDBCompat == Enable;
+
   if (DwarfAccelTables == Default)
     HasDwarfAccelTables = IsDarwin;
   else
@@ -1885,10 +1898,10 @@ void DwarfDebug::emitSectionLabels() {
   DwarfLineSectionSym =
     emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
   emitSectionSym(Asm, TLOF.getDwarfLocSection());
-  if (HasDwarfPubSections) {
+  if (HasDwarfPubSections)
     emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
+  if (useDarwinGDBCompat() || HasDwarfPubSections)
     emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
-  }
   DwarfStrSectionSym =
     emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
   if (useSplitDwarf()) {

test/DebugInfo/X86/debug-info-static-member.ll

@@ -151,6 +151,7 @@ declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
 ; DARWINP:      DW_AT_external
 ; DARWINP:      DW_AT_declaration
 ; DARWINP:      DW_AT_accessibility [DW_FORM_data1]   (0x03)
+; DARWINP:      DW_AT_MIPS_linkage_name {{.*}} "_ZN1C1aE"
 ; DARWINP:      DW_TAG_member
 ; DARWINP-NEXT: DW_AT_name {{.*}} "const_a"
 ; DARWINP:      DW_AT_external
@@ -160,6 +161,7 @@ declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
 ; DARWINP:      0x[[DECL_B:[0-9a-f]+]]: DW_TAG_member
 ; DARWINP-NEXT: DW_AT_name {{.*}} "b"
 ; DARWINP:      DW_AT_accessibility [DW_FORM_data1]   (0x02)
+; DARWINP:      DW_AT_MIPS_linkage_name {{.*}} "_ZN1C1bE"
 ; DARWINP:      DW_TAG_member
 ; DARWINP-NEXT: DW_AT_name {{.*}} "const_b"
 ; DARWINP:      DW_AT_accessibility [DW_FORM_data1]   (0x02)
@@ -167,6 +169,7 @@ declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
 ; DARWINP:      0x[[DECL_C:[0-9a-f]+]]: DW_TAG_member
 ; DARWINP-NEXT: DW_AT_name {{.*}} "c"
 ; DARWINP:      DW_AT_accessibility [DW_FORM_data1]   (0x01)
+; DARWINP:      DW_AT_MIPS_linkage_name {{.*}} "_ZN1C1cE"
 ; DARWINP:      DW_TAG_member
 ; DARWINP-NEXT: DW_AT_name {{.*}} "const_c"
 ; DARWINP:      DW_AT_accessibility [DW_FORM_data1]   (0x01)

test/DebugInfo/X86/linkage-name.ll

@@ -1,4 +1,4 @@
-; RUN: llc -mtriple=x86_64-macosx %s -o %t -filetype=obj
+; RUN: llc -mtriple=x86_64-macosx -darwin-gdb-compat=Disable %s -o %t -filetype=obj
 ; RUN: llvm-dwarfdump -debug-dump=info %t | FileCheck %s
 
 ; CHECK: DW_TAG_subprogram [9] *