Allow optionally generating pubnames section in DWARF info. Introduce

option "generate-dwarf-pubnames" to control it, set to "false" by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174981 91177308-0d34-0410-b5e6-96231b3b80d8

7 files changed, 226 insertions, 2 deletions

diff --git a/include/llvm/MC/MCObjectFileInfo.h b/include/llvm/MC/MCObjectFileInfo.h
index c52130a094..c8d748420e 100644
--- a/include/llvm/MC/MCObjectFileInfo.h
+++ b/include/llvm/MC/MCObjectFileInfo.h
@@ -97,6 +97,9 @@ protected:
   const MCSection *DwarfARangesSection;
   const MCSection *DwarfRangesSection;
   const MCSection *DwarfMacroInfoSection;
+  // The pubnames section is no longer generated by default.  The generation
+  // can be enabled by a compiler flag.
+  const MCSection *DwarfPubNamesSection;
 
   // DWARF5 Experimental Debug Info Sections
   /// DwarfAccelNamesSection, DwarfAccelObjCSection,
@@ -209,6 +212,7 @@ public:
   const MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
   const MCSection *getDwarfLineSection() const { return DwarfLineSection; }
   const MCSection *getDwarfFrameSection() const { return DwarfFrameSection; }
+  const MCSection *getDwarfPubNamesSection() const{return DwarfPubNamesSection;}
   const MCSection *getDwarfPubTypesSection() const{return DwarfPubTypesSection;}
   const MCSection *getDwarfDebugInlineSection() const {
     return DwarfDebugInlineSection;
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index dad1054872..93b00fb522 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -1311,8 +1311,10 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
     addType(VariableDIE, GTy);
 
     // Add scoping info.
-    if (!GV.isLocalToUnit())
+    if (!GV.isLocalToUnit()) {
       addFlag(VariableDIE, dwarf::DW_AT_external);
+      addGlobalName(GV.getName(), VariableDIE);
+    }
 
     // Add line number info.
     addSourceLine(VariableDIE, GV);
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index c7662f992e..77bf6a9e50 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -64,6 +64,10 @@ class CompileUnit {
   /// descriptors to debug information entries using a DIEEntry proxy.
   DenseMap<const MDNode *, DIEEntry *> MDNodeToDIEEntryMap;
 
+  /// GlobalNames - A map of globally visible named entities for this unit.
+  ///
+  StringMap<DIE*> GlobalNames;
+
   /// GlobalTypes - A map of globally visible types for this unit.
   ///
   StringMap<DIE*> GlobalTypes;
@@ -99,6 +103,7 @@ public:
   unsigned getUniqueID()            const { return UniqueID; }
   unsigned getLanguage()            const { return Language; }
   DIE* getCUDie()                   const { return CUDie.get(); }
+  const StringMap<DIE*> &getGlobalNames() const { return GlobalNames; }
   const StringMap<DIE*> &getGlobalTypes() const { return GlobalTypes; }
 
   const StringMap<std::vector<DIE*> > &getAccelNames() const {
@@ -119,6 +124,10 @@ public:
   ///
   bool hasContent() const { return !CUDie->getChildren().empty(); }
 
+  /// addGlobalName - Add a new global entity to the compile unit.
+  ///
+  void addGlobalName(StringRef Name, DIE *Die) { GlobalNames[Name] = Die; }
+
   /// addGlobalType - Add a new global type to the compile unit.
   ///
   void addGlobalType(DIType Ty);
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 6d3759d19a..0982dbb831 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -54,6 +54,10 @@ static cl::opt<bool> UnknownLocations("use-unknown-locations", cl::Hidden,
      cl::desc("Make an absence of debug location information explicit."),
      cl::init(false));
 
+static cl::opt<bool> GenerateDwarfPubNamesSection("generate-dwarf-pubnames",
+     cl::Hidden, cl::ZeroOrMore, cl::init(false),
+     cl::desc("Generate DWARF pubnames section"));
+
 namespace {
   enum DefaultOnOff {
     Default, Enable, Disable
@@ -733,7 +737,9 @@ void DwarfDebug::constructSubprogramDIE(CompileUnit *TheCU,
   // Add to context owner.
   TheCU->addToContextOwner(SubprogramDie, SP.getContext());
 
-  return;
+  // Expose as global, if requested.
+  if (GenerateDwarfPubNamesSection)
+    TheCU->addGlobalName(SP.getName(), SubprogramDie);
 }
 
 // Collect debug info from named mdnodes such as llvm.dbg.enum and llvm.dbg.ty.
@@ -1028,6 +1034,10 @@ void DwarfDebug::endModule() {
     emitAccelTypes();
   }
 
+  // Emit info into a debug pubnames section, if requested.
+  if (GenerateDwarfPubNamesSection)
+    emitDebugPubnames();
+
   // Emit info into a debug pubtypes section.
   // TODO: When we don't need the option anymore we can
   // remove all of the code that adds to the table.
@@ -1784,6 +1794,8 @@ void DwarfDebug::emitSectionLabels() {
   DwarfLineSectionSym =
     emitSectionSym(Asm, TLOF.getDwarfLineSection(), "section_line");
   emitSectionSym(Asm, TLOF.getDwarfLocSection());
+  if (GenerateDwarfPubNamesSection)
+    emitSectionSym(Asm, TLOF.getDwarfPubNamesSection());
   emitSectionSym(Asm, TLOF.getDwarfPubTypesSection());
   DwarfStrSectionSym =
     emitSectionSym(Asm, TLOF.getDwarfStrSection(), "info_string");
@@ -2119,6 +2131,61 @@ void DwarfDebug::emitAccelTypes() {
   AT.Emit(Asm, SectionBegin, &InfoHolder);
 }
 
+/// emitDebugPubnames - Emit visible names into a debug pubnames section.
+///
+void DwarfDebug::emitDebugPubnames() {
+  const MCSection *ISec = Asm->getObjFileLowering().getDwarfInfoSection();
+
+  typedef DenseMap<const MDNode*, CompileUnit*> CUMapType;
+  for (CUMapType::iterator I = CUMap.begin(), E = CUMap.end(); I != E; ++I) {
+    CompileUnit *TheCU = I->second;
+    unsigned ID = TheCU->getUniqueID();
+
+    if (TheCU->getGlobalNames().empty())
+      continue;
+
+    // Start the dwarf pubnames section.
+    Asm->OutStreamer.SwitchSection(
+      Asm->getObjFileLowering().getDwarfPubNamesSection());
+
+    Asm->OutStreamer.AddComment("Length of Public Names Info");
+    Asm->EmitLabelDifference(Asm->GetTempSymbol("pubnames_end", ID),
+                             Asm->GetTempSymbol("pubnames_begin", ID), 4);
+
+    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("pubnames_begin", ID));
+
+    Asm->OutStreamer.AddComment("DWARF Version");
+    Asm->EmitInt16(dwarf::DWARF_VERSION);
+
+    Asm->OutStreamer.AddComment("Offset of Compilation Unit Info");
+    Asm->EmitSectionOffset(Asm->GetTempSymbol(ISec->getLabelBeginName(), ID),
+                           DwarfInfoSectionSym);
+
+    Asm->OutStreamer.AddComment("Compilation Unit Length");
+    Asm->EmitLabelDifference(Asm->GetTempSymbol(ISec->getLabelEndName(), ID),
+                             Asm->GetTempSymbol(ISec->getLabelBeginName(), ID),
+                             4);
+
+    const StringMap<DIE*> &Globals = TheCU->getGlobalNames();
+    for (StringMap<DIE*>::const_iterator
+           GI = Globals.begin(), GE = Globals.end(); GI != GE; ++GI) {
+      const char *Name = GI->getKeyData();
+      const DIE *Entity = GI->second;
+
+      Asm->OutStreamer.AddComment("DIE offset");
+      Asm->EmitInt32(Entity->getOffset());
+
+      if (Asm->isVerbose())
+        Asm->OutStreamer.AddComment("External Name");
+      Asm->OutStreamer.EmitBytes(StringRef(Name, strlen(Name)+1), 0);
+    }
+
+    Asm->OutStreamer.AddComment("End Mark");
+    Asm->EmitInt32(0);
+    Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("pubnames_end", ID));
+  }
+}
+
 void DwarfDebug::emitDebugPubTypes() {
   for (DenseMap<const MDNode *, CompileUnit *>::iterator I = CUMap.begin(),
          E = CUMap.end(); I != E; ++I) {
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 7d57a829af..7b56815040 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -500,6 +500,9 @@ private:
   /// \brief Emit type dies into a hashed accelerator table.
   void emitAccelTypes();
 
+  /// \brief Emit visible names into a debug pubnames section.
+  void emitDebugPubnames();
+
   /// \brief Emit visible types into a debug pubtypes section.
   void emitDebugPubTypes();
 
diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index ae0abde86a..2e1a045569 100644
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -186,6 +186,10 @@ void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
     Ctx->getMachOSection("__DWARF", "__debug_frame",
                          MCSectionMachO::S_ATTR_DEBUG,
                          SectionKind::getMetadata());
+  DwarfPubNamesSection =
+    Ctx->getMachOSection("__DWARF", "__debug_pubnames",
+                         MCSectionMachO::S_ATTR_DEBUG,
+                         SectionKind::getMetadata());
   DwarfPubTypesSection =
     Ctx->getMachOSection("__DWARF", "__debug_pubtypes",
                          MCSectionMachO::S_ATTR_DEBUG,
@@ -400,6 +404,9 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
   DwarfFrameSection =
     Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
                        SectionKind::getMetadata());
+  DwarfPubNamesSection =
+    Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0,
+                       SectionKind::getMetadata());
   DwarfPubTypesSection =
     Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
                        SectionKind::getMetadata());
@@ -543,6 +550,11 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
                         COFF::IMAGE_SCN_MEM_READ,
                         SectionKind::getMetadata());
+  DwarfPubNamesSection =
+    Ctx->getCOFFSection(".debug_pubnames",
+                        COFF::IMAGE_SCN_MEM_DISCARDABLE |
+                        COFF::IMAGE_SCN_MEM_READ,
+                        SectionKind::getMetadata());
   DwarfPubTypesSection =
     Ctx->getCOFFSection(".debug_pubtypes",
                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
diff --git a/test/DebugInfo/dwarf-public-names.ll b/test/DebugInfo/dwarf-public-names.ll
new file mode 100644
index 0000000000..c850c544af
--- /dev/null
+++ b/test/DebugInfo/dwarf-public-names.ll
@@ -0,0 +1,127 @@
+; RUN: llc -generate-dwarf-pubnames -filetype=obj -o %t.o < %s
+; RUN: llvm-dwarfdump -debug-dump=pubnames %t.o | FileCheck %s
+;
+; ModuleID = 'dwarf-public-names.cpp'
+;
+; Generated from:
+;
+; struct C {
+;   void member_function();
+;   static int static_member_function();
+;   static int static_member_variable;
+; };
+;
+; int C::static_member_variable = 0;
+;
+; void C::member_function() {
+;   static_member_variable = 0;
+; }
+;
+; int C::static_member_function() {
+;   return static_member_variable;
+; }
+;
+; C global_variable;
+;
+; int global_function() {
+;   return -1;
+; }
+;
+; namespace ns {
+;   void global_namespace_function() {
+;     global_variable.member_function();
+;   }
+;   int global_namespace_variable = 1;
+; }
+
+; Skip the output to the header of the pubnames section.
+; CHECK: debug_pubnames
+
+; Check for each name in the output.
+; CHECK: global_namespace_variable
+; CHECK: global_namespace_function
+; CHECK: static_member_function
+; CHECK: global_variable
+; CHECK: global_function
+; CHECK: member_function
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.C = type { i8 }
+
+@_ZN1C22static_member_variableE = global i32 0, align 4
+@global_variable = global %struct.C zeroinitializer, align 1
+@_ZN2ns25global_namespace_variableE = global i32 1, align 4
+
+define void @_ZN1C15member_functionEv(%struct.C* %this) nounwind uwtable align 2 {
+entry:
+  %this.addr = alloca %struct.C*, align 8
+  store %struct.C* %this, %struct.C** %this.addr, align 8
+  call void @llvm.dbg.declare(metadata !{%struct.C** %this.addr}, metadata !28), !dbg !30
+  %this1 = load %struct.C** %this.addr
+  store i32 0, i32* @_ZN1C22static_member_variableE, align 4, !dbg !31
+  ret void, !dbg !32
+}
+
+declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
+
+define i32 @_ZN1C22static_member_functionEv() nounwind uwtable align 2 {
+entry:
+  %0 = load i32* @_ZN1C22static_member_variableE, align 4, !dbg !33
+  ret i32 %0, !dbg !33
+}
+
+define i32 @_Z15global_functionv() nounwind uwtable {
+entry:
+  ret i32 -1, !dbg !34
+}
+
+define void @_ZN2ns25global_namespace_functionEv() nounwind uwtable {
+entry:
+  call void @_ZN1C15member_functionEv(%struct.C* @global_variable), !dbg !35
+  ret void, !dbg !36
+}
+
+attributes #0 = { nounwind uwtable }
+attributes #1 = { nounwind readnone }
+
+!llvm.dbg.cu = !{!0}
+
+!0 = metadata !{i32 786449, i32 0, i32 4, metadata !"dwarf-public-names.cpp", metadata !"/usr2/kparzysz/s.hex/t", metadata !"clang version 3.3 (http://llvm.org/git/clang.git a09cd8103a6a719cb2628cdf0c91682250a17bd2) (http://llvm.org/git/llvm.git 47d03cec0afca0c01ae42b82916d1d731716cd20)", i1 true, i1 false, metadata !"", i32 0, metadata !1, metadata !1, metadata !2, metadata !24} ; [ DW_TAG_compile_unit ] [/usr2/kparzysz/s.hex/t/dwarf-public-names.cpp] [DW_LANG_C_plus_plus]
+!1 = metadata !{i32 0}
+!2 = metadata !{metadata !3, metadata !18, metadata !19, metadata !20}
+!3 = metadata !{i32 786478, i32 0, null, metadata !"member_function", metadata !"member_function", metadata !"_ZN1C15member_functionEv", metadata !4, i32 9, metadata !5, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, void (%struct.C*)* @_ZN1C15member_functionEv, null, metadata !12, metadata !1, i32 9} ; [ DW_TAG_subprogram ] [line 9] [def] [member_function]
+!4 = metadata !{i32 786473, metadata !"dwarf-public-names.cpp", metadata !"/usr2/kparzysz/s.hex/t", null} ; [ DW_TAG_file_type ]
+!5 = metadata !{i32 786453, i32 0, metadata !"", i32 0, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !6, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!6 = metadata !{null, metadata !7}
+!7 = metadata !{i32 786447, i32 0, metadata !"", i32 0, i32 0, i64 64, i64 64, i64 0, i32 1088, metadata !8} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [artificial] [from C]
+!8 = metadata !{i32 786451, null, metadata !"C", metadata !4, i32 1, i64 8, i64 8, i32 0, i32 0, null, metadata !9, i32 0, null, null} ; [ DW_TAG_structure_type ] [C] [line 1, size 8, align 8, offset 0] [from ]
+!9 = metadata !{metadata !10, metadata !12, metadata !14}
+!10 = metadata !{i32 786445, metadata !8, metadata !"static_member_variable", metadata !4, i32 4, i64 0, i64 0, i64 0, i32 4096, metadata !11, null} ; [ DW_TAG_member ] [static_member_variable] [line 4, size 0, align 0, offset 0] [static] [from int]
+!11 = metadata !{i32 786468, null, metadata !"int", null, 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]
+!12 = metadata !{i32 786478, i32 0, metadata !8, metadata !"member_function", metadata !"member_function", metadata !"_ZN1C15member_functionEv", metadata !4, i32 2, metadata !5, i1 false, i1 false, i32 0, i32 0, null, i32 256, i1 false, null, null, i32 0, metadata !13, i32 2} ; [ DW_TAG_subprogram ] [line 2] [member_function]
+!13 = metadata !{i32 786468}                      ; [ DW_TAG_base_type ] [line 0, size 0, align 0, offset 0]
+!14 = metadata !{i32 786478, i32 0, metadata !8, metadata !"static_member_function", metadata !"static_member_function", metadata !"_ZN1C22static_member_functionEv", metadata !4, i32 3, metadata !15, i1 false, i1 false, i32 0, i32 0, null, i32 256, i1 false, null, null, i32 0, metadata !17, i32 3} ; [ DW_TAG_subprogram ] [line 3] [static_member_function]
+!15 = metadata !{i32 786453, i32 0, metadata !"", i32 0, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !16, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!16 = metadata !{metadata !11}
+!17 = metadata !{i32 786468}                      ; [ DW_TAG_base_type ] [line 0, size 0, align 0, offset 0]
+!18 = metadata !{i32 786478, i32 0, null, metadata !"static_member_function", metadata !"static_member_function", metadata !"_ZN1C22static_member_functionEv", metadata !4, i32 13, metadata !15, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 ()* @_ZN1C22static_member_functionEv, null, metadata !14, metadata !1, i32 13} ; [ DW_TAG_subprogram ] [line 13] [def] [static_member_function]
+!19 = metadata !{i32 786478, i32 0, metadata !4, metadata !"global_function", metadata !"global_function", metadata !"_Z15global_functionv", metadata !4, i32 19, metadata !15, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 ()* @_Z15global_functionv, null, null, metadata !1, i32 19} ; [ DW_TAG_subprogram ] [line 19] [def] [global_function]
+!20 = metadata !{i32 786478, i32 0, metadata !21, metadata !"global_namespace_function", metadata !"global_namespace_function", metadata !"_ZN2ns25global_namespace_functionEv", metadata !4, i32 24, metadata !22, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, void ()* @_ZN2ns25global_namespace_functionEv, null, null, metadata !1, i32 24} ; [ DW_TAG_subprogram ] [line 24] [def] [global_namespace_function]
+!21 = metadata !{i32 786489, null, metadata !"ns", metadata !4, i32 23} ; [ DW_TAG_namespace ] [/usr2/kparzysz/s.hex/t/dwarf-public-names.cpp]
+!22 = metadata !{i32 786453, i32 0, metadata !"", i32 0, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !23, i32 0, i32 0} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!23 = metadata !{null}
+!24 = metadata !{metadata !25, metadata !26, metadata !27}
+!25 = metadata !{i32 786484, i32 0, metadata !8, metadata !"static_member_variable", metadata !"static_member_variable", metadata !"_ZN1C22static_member_variableE", metadata !4, i32 7, metadata !11, i32 0, i32 1, i32* @_ZN1C22static_member_variableE, metadata !10} ; [ DW_TAG_variable ] [static_member_variable] [line 7] [def]
+!26 = metadata !{i32 786484, i32 0, null, metadata !"global_variable", metadata !"global_variable", metadata !"", metadata !4, i32 17, metadata !8, i32 0, i32 1, %struct.C* @global_variable, null} ; [ DW_TAG_variable ] [global_variable] [line 17] [def]
+!27 = metadata !{i32 786484, i32 0, metadata !21, metadata !"global_namespace_variable", metadata !"global_namespace_variable", metadata !"_ZN2ns25global_namespace_variableE", metadata !4, i32 27, metadata !11, i32 0, i32 1, i32* @_ZN2ns25global_namespace_variableE, null} ; [ DW_TAG_variable ] [global_namespace_variable] [line 27] [def]
+!28 = metadata !{i32 786689, metadata !3, metadata !"this", metadata !4, i32 16777225, metadata !29, i32 1088, i32 0} ; [ DW_TAG_arg_variable ] [this] [line 9]
+!29 = metadata !{i32 786447, null, metadata !"", null, i32 0, i64 64, i64 64, i64 0, i32 0, metadata !8} ; [ DW_TAG_pointer_type ] [line 0, size 64, align 64, offset 0] [from C]
+!30 = metadata !{i32 9, i32 0, metadata !3, null}
+!31 = metadata !{i32 10, i32 0, metadata !3, null}
+!32 = metadata !{i32 11, i32 0, metadata !3, null}
+!33 = metadata !{i32 14, i32 0, metadata !18, null}
+!34 = metadata !{i32 20, i32 0, metadata !19, null}
+!35 = metadata !{i32 25, i32 0, metadata !20, null}
+!36 = metadata !{i32 26, i32 0, metadata !20, null}