Reapply "DebugInfo: Don't put fission type units in comdat sections."

This recommits r208930, r208933, and r208975 (by reverting r209338) and
reverts r209529 (the FIXME to readd this functionality once the tools
were fixed) now that DWP has been fixed to cope with a single section
for all fission type units.

Original commit message:

"Since type units in the dwo file are handled by a debug aware tool,
they don't need to leverage the ELF comdat grouping to implement
deduplication. Avoid creating all the .group sections for these as a
space optimization."

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213956 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/MC/MCObjectFileInfo.h b/include/llvm/MC/MCObjectFileInfo.h
index 4d1715eccf5a00e868f4a201205648b2f8137fbf..5e7c7709aa4c4de55871bb51d44049c62f00bec0 100644 (file)
--- a/include/llvm/MC/MCObjectFileInfo.h
+++ b/include/llvm/MC/MCObjectFileInfo.h
@@ -116,6 +116,7 @@ protected:
 
   /// These are used for the Fission separate debug information files.
   const MCSection *DwarfInfoDWOSection;
+  const MCSection *DwarfTypesDWOSection;
   const MCSection *DwarfAbbrevDWOSection;
   const MCSection *DwarfStrDWOSection;
   const MCSection *DwarfLineDWOSection;
@@ -261,7 +262,9 @@ public:
     return DwarfInfoDWOSection;
   }
   const MCSection *getDwarfTypesSection(uint64_t Hash) const;
-  const MCSection *getDwarfTypesDWOSection(uint64_t Hash) const;
+  const MCSection *getDwarfTypesDWOSection() const {
+    return DwarfTypesDWOSection;
+  }
   const MCSection *getDwarfAbbrevDWOSection() const {
     return DwarfAbbrevDWOSection;
   }

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 99e7a272d7fdfa952a623f30cdd997c75d54b258..b45d5917615eb60ddebcda023b8e653f53218e2e 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1640,9 +1640,12 @@ void DwarfDebug::emitSectionLabels() {
   // Dwarf sections base addresses.
   DwarfInfoSectionSym =
       emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
-  if (useSplitDwarf())
+  if (useSplitDwarf()) {
     DwarfInfoDWOSectionSym =
         emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
+    DwarfTypesDWOSectionSym =
+        emitSectionSym(Asm, TLOF.getDwarfTypesDWOSection(), "section_types_dwo");
+  }
   DwarfAbbrevSectionSym =
       emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
   if (useSplitDwarf())
@@ -2406,9 +2409,9 @@ void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
   bool TopLevelType = TypeUnitsUnderConstruction.empty();
   AddrPool.resetUsedFlag();
 
-  auto OwnedUnit =
-      make_unique<DwarfTypeUnit>(InfoHolder.getUnits().size(), CU, Asm, this,
-                                 &InfoHolder, getDwoLineTable(CU));
+  auto OwnedUnit = make_unique<DwarfTypeUnit>(
+      InfoHolder.getUnits().size() + TypeUnitsUnderConstruction.size(), CU, Asm,
+      this, &InfoHolder, getDwoLineTable(CU));
   DwarfTypeUnit &NewTU = *OwnedUnit;
   DIE &UnitDie = NewTU.getUnitDie();
   TU = &NewTU;
@@ -2421,15 +2424,14 @@ void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
   uint64_t Signature = makeTypeSignature(Identifier);
   NewTU.setTypeSignature(Signature);
 
-  if (!useSplitDwarf())
+  if (useSplitDwarf())
+    NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection(),
+                      DwarfTypesDWOSectionSym);
+  else {
     CU.applyStmtList(UnitDie);
-
-  // FIXME: Skip using COMDAT groups for type units in the .dwo file once tools
-  // such as DWP ( http://gcc.gnu.org/wiki/DebugFissionDWP ) can cope with it.
-  NewTU.initSection(
-      useSplitDwarf()
-          ? Asm->getObjFileLowering().getDwarfTypesDWOSection(Signature)
-          : Asm->getObjFileLowering().getDwarfTypesSection(Signature));
+    NewTU.initSection(
+        Asm->getObjFileLowering().getDwarfTypesSection(Signature));
+  }
 
   NewTU.setType(NewTU.createTypeDIE(CTy));
 

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index ffe4843b98729ecf02f160f4520936183a44d4a3..f45314ae0f1f1e761d68b277835af5eafd45194b 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -258,6 +258,7 @@ class DwarfDebug : public AsmPrinterHandler {
   MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym, *DwarfAddrSectionSym;
   MCSymbol *FunctionBeginSym, *FunctionEndSym;
   MCSymbol *DwarfInfoDWOSectionSym, *DwarfAbbrevDWOSectionSym;
+  MCSymbol *DwarfTypesDWOSectionSym;
   MCSymbol *DwarfStrDWOSectionSym;
   MCSymbol *DwarfGnuPubNamesSectionSym, *DwarfGnuPubTypesSectionSym;
 

diff --git a/lib/CodeGen/AsmPrinter/DwarfUnit.h b/lib/CodeGen/AsmPrinter/DwarfUnit.h
index b7b83b282d821bb1069367142166252ff4187964..a224c173369d1bc495242f1dbc533d51de9e98d6 100644 (file)
--- a/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -579,6 +579,10 @@ public:
            sizeof(uint32_t);                               // Type DIE Offset
   }
   void initSection(const MCSection *Section);
+  // Bring in the base function (taking two args, including the section symbol)
+  // for use when building DWO type units (they don't go in unique comdat
+  // sections)
+  using DwarfUnit::initSection;
   DwarfCompileUnit &getCU() override { return CU; }
 
 protected:

diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp
index ed6351866c00f2647b4e20d09bc20a6ca96c360f..df5787c7426e9e9829c375c3465248d74ae3002d 100644 (file)
--- a/lib/MC/MCObjectFileInfo.cpp
+++ b/lib/MC/MCObjectFileInfo.cpp
@@ -561,6 +561,9 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
   DwarfInfoDWOSection =
     Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0,
                        SectionKind::getMetadata());
+  DwarfTypesDWOSection =
+    Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS, 0,
+                       SectionKind::getMetadata());
   DwarfAbbrevDWOSection =
     Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0,
                        SectionKind::getMetadata());
@@ -736,6 +739,10 @@ void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
                           COFF::IMAGE_SCN_MEM_READ,
                           SectionKind::getMetadata());
+  DwarfTypesDWOSection =
+      Ctx->getCOFFSection(".debug_types.dwo", COFF::IMAGE_SCN_MEM_DISCARDABLE |
+                                                  COFF::IMAGE_SCN_MEM_READ,
+                          SectionKind::getMetadata());
   DwarfAbbrevDWOSection =
       Ctx->getCOFFSection(".debug_abbrev.dwo",
                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
@@ -847,13 +854,6 @@ const MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
                             SectionKind::getMetadata(), 0, utostr(Hash));
 }
 
-const MCSection *
-MCObjectFileInfo::getDwarfTypesDWOSection(uint64_t Hash) const {
-  return Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS,
-                            ELF::SHF_GROUP, SectionKind::getMetadata(), 0,
-                            utostr(Hash));
-}
-
 void MCObjectFileInfo::InitEHFrameSection() {
   if (Env == IsMachO)
     EHFrameSection =

diff --git a/test/DebugInfo/X86/generate-odr-hash.ll b/test/DebugInfo/X86/generate-odr-hash.ll
index 2256b3e212a74583779ef5f0bcd6c05eb94fd0e0..a232e2f76e7c03b0b9bf2a6dc56a548eb7016493 100644 (file)
--- a/test/DebugInfo/X86/generate-odr-hash.ll
+++ b/test/DebugInfo/X86/generate-odr-hash.ll
@@ -1,10 +1,12 @@
 ; REQUIRES: object-emission
 
-; RUN: llc %s -o %t -filetype=obj -O0 -generate-type-units -mtriple=x86_64-unknown-linux-gnu
+; RUN: llc < %s -o %t -filetype=obj -O0 -generate-type-units -mtriple=x86_64-unknown-linux-gnu
 ; RUN: llvm-dwarfdump %t | FileCheck --check-prefix=CHECK --check-prefix=SINGLE %s
+; RUN: llvm-readobj -s -t %t | FileCheck --check-prefix=OBJ_COMMON %s
 
-; RUN: llc %s -split-dwarf=Enable -o %t -filetype=obj -O0 -generate-type-units -mtriple=x86_64-unknown-linux-gnu
+; RUN: llc < %s -split-dwarf=Enable -o %t -filetype=obj -O0 -generate-type-units -mtriple=x86_64-unknown-linux-gnu
 ; RUN: llvm-dwarfdump %t | FileCheck --check-prefix=CHECK --check-prefix=FISSION %s
+; RUN: llvm-readobj -s -t %t | FileCheck --check-prefix=OBJ_COMMON --check-prefix=OBJ_FISSION %s
 
 ; Generated from bar.cpp:
 
@@ -161,6 +163,20 @@
 ; CHECK-DAG: [[WOMBAT]] "wombat"
 ; CHECK-DAG: [[FLUFFY]] "echidna::capybara::mongoose::fluffy"
 
+; Make sure debug_types are in comdat groups. This could be more rigid to check
+; that they're the right comdat groups (each type in a separate comdat group,
+; etc)
+; OBJ_COMMON: Name: .debug_types (
+; OBJ_COMMON-NOT: }
+; OBJ_COMMON: SHF_GROUP
+
+; Fission type units don't go in comdat groups, since their linker is debug
+; aware it's handled using the debug info semantics rather than raw ELF object
+; semantics.
+; OBJ_FISSION: Name: .debug_types.dwo (
+; OBJ_FISSION-NOT: SHF_GROUP
+; OBJ_FISSION: }
+
 %struct.bar = type { i8 }
 %"class.echidna::capybara::mongoose::fluffy" = type { i32, i32 }
 %"struct.<anonymous namespace>::walrus" = type { i8 }