Improved macro emission in dwarf.

Changed emitting offset of macinfo entry into compiler unit DIE to use "addSectionLabel" method rather than explicitly calculating size/offset of macro entry.

Differential Revision: http://reviews.llvm.org/D16292

llvm-svn: 259358

llvm/include/llvm/CodeGen/DIE.h

@@ -29,48 +29,6 @@ class MCSymbol;
 class raw_ostream;
 class DwarfTypeUnit;
 
-// AsmStreamerBase - A base abstract interface class defines methods that
-// can be implemented to stream objects or can be implemented to
-// calculate the size of the streamed objects.
-// The derived classes will use an AsmPrinter to implement the methods.
-//
-// TODO: complete this interface and use it to merge EmitValue and SizeOf
-//       methods in the DIE classes below.
-class AsmStreamerBase {
-protected:
-  const AsmPrinter *AP;
-  AsmStreamerBase(const AsmPrinter *AP) : AP(AP) {}
-
-public:
-  virtual ~AsmStreamerBase() {}
-  virtual unsigned emitULEB128(uint64_t Value, const char *Desc = nullptr,
-                               unsigned PadTo = 0) = 0;
-  virtual unsigned emitInt8(unsigned char Value) = 0;
-  virtual unsigned emitBytes(StringRef Data) = 0;
-};
-
-/// EmittingAsmStreamer - Implements AbstractAsmStreamer to stream objects.
-/// Notice that the return value is not the actual size of the streamed object.
-/// For size calculation use SizeReporterAsmStreamer.
-class EmittingAsmStreamer : public AsmStreamerBase {
-public:
-  EmittingAsmStreamer(const AsmPrinter *AP) : AsmStreamerBase(AP) {}
-  unsigned emitULEB128(uint64_t Value, const char *Desc = nullptr,
-                       unsigned PadTo = 0) override;
-  unsigned emitInt8(unsigned char Value) override;
-  unsigned emitBytes(StringRef Data) override;
-};
-
-/// SizeReporterAsmStreamer - Only reports the size of the streamed objects.
-class SizeReporterAsmStreamer : public AsmStreamerBase {
-public:
-  SizeReporterAsmStreamer(const AsmPrinter *AP) : AsmStreamerBase(AP) {}
-  unsigned emitULEB128(uint64_t Value, const char *Desc = nullptr,
-                       unsigned PadTo = 0) override;
-  unsigned emitInt8(unsigned char Value) override;
-  unsigned emitBytes(StringRef Data) override;
-};
-
 //===--------------------------------------------------------------------===//
 /// DIEAbbrevData - Dwarf abbreviation data, describes one attribute of a
 /// Dwarf abbreviation.

llvm/lib/CodeGen/AsmPrinter/DIE.cpp

@@ -31,39 +31,6 @@
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
-//===----------------------------------------------------------------------===//
-// EmittingAsmStreamer Implementation
-//===----------------------------------------------------------------------===//
-unsigned EmittingAsmStreamer::emitULEB128(uint64_t Value, const char *Desc,
-                                          unsigned PadTo) {
-  AP->EmitULEB128(Value, Desc, PadTo);
-  return 0;
-}
-
-unsigned EmittingAsmStreamer::emitInt8(unsigned char Value) {
-  AP->EmitInt8(Value);
-  return 0;
-}
-
-unsigned EmittingAsmStreamer::emitBytes(StringRef Data) {
-  AP->OutStreamer->EmitBytes(Data);
-  return 0;
-}
-
-//===----------------------------------------------------------------------===//
-// SizeReporterAsmStreamer Implementation
-//===----------------------------------------------------------------------===//
-unsigned SizeReporterAsmStreamer::emitULEB128(uint64_t Value, const char *Desc,
-                                              unsigned PadTo) {
-  return getULEB128Size(Value);
-}
-
-unsigned SizeReporterAsmStreamer::emitInt8(unsigned char Value) { return 1; }
-
-unsigned SizeReporterAsmStreamer::emitBytes(StringRef Data) {
-  return Data.size();
-}
-
 //===----------------------------------------------------------------------===//
 // DIEAbbrevData Implementation
 //===----------------------------------------------------------------------===//

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -22,6 +22,7 @@ DwarfCompileUnit::DwarfCompileUnit(unsigned UID, const DICompileUnit *Node,
     : DwarfUnit(UID, dwarf::DW_TAG_compile_unit, Node, A, DW, DWU),
       Skeleton(nullptr), BaseAddress(nullptr) {
   insertDIE(Node, &getUnitDie());
+  MacroLabelBegin = Asm->createTempSymbol("cu_macro_begin");
 }
 
 /// addLabelAddress - Add a dwarf label attribute data and value using

llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h

@@ -39,6 +39,9 @@ class DwarfCompileUnit : public DwarfUnit {
   /// The start of the unit within its section.
   MCSymbol *LabelBegin;
 
+  /// The start of the unit macro info within macro section.
+  MCSymbol *MacroLabelBegin;
+
   typedef llvm::SmallVector<const MDNode *, 8> ImportedEntityList;
   typedef llvm::DenseMap<const MDNode *, ImportedEntityList>
   ImportedEntityMap;
@@ -189,6 +192,10 @@ public:
     return LabelBegin;
   }
 
+  MCSymbol *getMacroLabelBegin() const {
+    return MacroLabelBegin;
+  }
+
   /// Add a new global name to the compile unit.
   void addGlobalName(StringRef Name, DIE &Die, const DIScope *Context) override;
 

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -561,8 +561,6 @@ void DwarfDebug::finalizeModuleInfo() {
   // Collect info for variables that were optimized out.
   collectDeadVariables();
 
-  unsigned MacroOffset = 0;
-  std::unique_ptr<AsmStreamerBase> AS(new SizeReporterAsmStreamer(Asm));
   // Handle anything that needs to be done on a per-unit basis after
   // all other generation.
   for (const auto &P : CUMap) {
@@ -617,13 +615,11 @@ void DwarfDebug::finalizeModuleInfo() {
     }
 
     auto *CUNode = cast<DICompileUnit>(P.first);
-    if (CUNode->getMacros()) {
-      // Compile Unit has macros, emit "DW_AT_macro_info" attribute.
-      U.addUInt(U.getUnitDie(), dwarf::DW_AT_macro_info,
-                dwarf::DW_FORM_sec_offset, MacroOffset);
-      // Update macro section offset
-      MacroOffset += handleMacroNodes(AS.get(), CUNode->getMacros(), U);
-    }
+    // If compile Unit has macros, emit "DW_AT_macro_info" attribute.
+    if (CUNode->getMacros())
+      U.addSectionLabel(U.getUnitDie(), dwarf::DW_AT_macro_info,
+                        U.getMacroLabelBegin(),
+                        TLOF.getDwarfMacinfoSection()->getBeginSymbol());
   }
 
   // Compute DIE offsets and sizes.
@@ -1865,65 +1861,56 @@ void DwarfDebug::emitDebugRanges() {
   }
 }
 
-unsigned DwarfDebug::handleMacroNodes(AsmStreamerBase *AS,
-                                      DIMacroNodeArray Nodes,
-                                      DwarfCompileUnit &U) {
-  unsigned Size = 0;
+void DwarfDebug::handleMacroNodes(DIMacroNodeArray Nodes, DwarfCompileUnit &U) {
   for (auto *MN : Nodes) {
     if (auto *M = dyn_cast<DIMacro>(MN))
-      Size += emitMacro(AS, *M);
+      emitMacro(*M);
     else if (auto *F = dyn_cast<DIMacroFile>(MN))
-      Size += emitMacroFile(AS, *F, U);
+      emitMacroFile(*F, U);
     else
       llvm_unreachable("Unexpected DI type!");
   }
-  return Size;
 }
 
-unsigned DwarfDebug::emitMacro(AsmStreamerBase *AS, DIMacro &M) {
-  int Size = 0;
-  Size += AS->emitULEB128(M.getMacinfoType());
-  Size += AS->emitULEB128(M.getLine());
+void DwarfDebug::emitMacro(DIMacro &M) {
+  Asm->EmitULEB128(M.getMacinfoType());
+  Asm->EmitULEB128(M.getLine());
   StringRef Name = M.getName();
   StringRef Value = M.getValue();
-  Size += AS->emitBytes(Name);
+  Asm->OutStreamer->EmitBytes(Name);
   if (!Value.empty()) {
     // There should be one space between macro name and macro value.
-    Size += AS->emitInt8(' ');
-    Size += AS->emitBytes(Value);
+    Asm->EmitInt8(' ');
+    Asm->OutStreamer->EmitBytes(Value);
   }
-  Size += AS->emitInt8('\0');
-  return Size;
+  Asm->EmitInt8('\0');
 }
 
-unsigned DwarfDebug::emitMacroFile(AsmStreamerBase *AS, DIMacroFile &F,
-                                   DwarfCompileUnit &U) {
-  int Size = 0;
+void DwarfDebug::emitMacroFile(DIMacroFile &F, DwarfCompileUnit &U) {
   assert(F.getMacinfoType() == dwarf::DW_MACINFO_start_file);
-  Size += AS->emitULEB128(dwarf::DW_MACINFO_start_file);
-  Size += AS->emitULEB128(F.getLine());
+  Asm->EmitULEB128(dwarf::DW_MACINFO_start_file);
+  Asm->EmitULEB128(F.getLine());
   DIFile *File = F.getFile();
   unsigned FID =
       U.getOrCreateSourceID(File->getFilename(), File->getDirectory());
-  Size += AS->emitULEB128(FID);
-  Size += handleMacroNodes(AS, F.getElements(), U);
-  Size += AS->emitULEB128(dwarf::DW_MACINFO_end_file);
-  return Size;
+  Asm->EmitULEB128(FID);
+  handleMacroNodes(F.getElements(), U);
+  Asm->EmitULEB128(dwarf::DW_MACINFO_end_file);
 }
 
 /// Emit macros into a debug macinfo section.
 void DwarfDebug::emitDebugMacinfo() {
-  if (MCSection *Macinfo = Asm->getObjFileLowering().getDwarfMacinfoSection()) {
   // Start the dwarf macinfo section.
-    Asm->OutStreamer->SwitchSection(Macinfo);
-  }
-  std::unique_ptr<AsmStreamerBase> AS(new EmittingAsmStreamer(Asm));
+  Asm->OutStreamer->SwitchSection(
+      Asm->getObjFileLowering().getDwarfMacinfoSection());
+
   for (const auto &P : CUMap) {
     auto &TheCU = *P.second;
     auto *SkCU = TheCU.getSkeleton();
     DwarfCompileUnit &U = SkCU ? *SkCU : TheCU;
     auto *CUNode = cast<DICompileUnit>(P.first);
-    handleMacroNodes(AS.get(), CUNode->getMacros(), U);
+    Asm->OutStreamer->EmitLabel(U.getMacroLabelBegin());
+    handleMacroNodes(CUNode->getMacros(), U);
   }
   Asm->OutStreamer->AddComment("End Of Macro List Mark");
   Asm->EmitInt8(0);

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

@@ -414,11 +414,9 @@ class DwarfDebug : public AsmPrinterHandler {
 
   /// Emit macros into a debug macinfo section.
   void emitDebugMacinfo();
-  unsigned emitMacro(AsmStreamerBase *AS, DIMacro &M);
-  unsigned emitMacroFile(AsmStreamerBase *AS, DIMacroFile &F,
-                         DwarfCompileUnit &U);
-  unsigned handleMacroNodes(AsmStreamerBase *AS, DIMacroNodeArray Nodes,
-                            DwarfCompileUnit &U);
+  void emitMacro(DIMacro &M);
+  void emitMacroFile(DIMacroFile &F, DwarfCompileUnit &U);
+  void handleMacroNodes(DIMacroNodeArray Nodes, DwarfCompileUnit &U);
 
   /// DWARF 5 Experimental Split Dwarf Emitters
 

llvm/lib/MC/MCObjectFileInfo.cpp

@@ -259,7 +259,7 @@ void MCObjectFileInfo::initMachOMCObjectFileInfo(Triple T) {
                            SectionKind::getMetadata(), "debug_range");
   DwarfMacinfoSection =
       Ctx->getMachOSection("__DWARF", "__debug_macinfo", MachO::S_ATTR_DEBUG,
-                           SectionKind::getMetadata());
+                           SectionKind::getMetadata(), "debug_macinfo");
   DwarfDebugInlineSection =
       Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
                            SectionKind::getMetadata());
@@ -510,8 +510,8 @@ void MCObjectFileInfo::initELFMCObjectFileInfo(Triple T) {
       Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0);
   DwarfRangesSection =
       Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0, "debug_range");
-  DwarfMacinfoSection =
-      Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0);
+  DwarfMacinfoSection = Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS,
+                                           0, "debug_macinfo");
 
   // DWARF5 Experimental Debug Info
 
@@ -700,7 +700,7 @@ void MCObjectFileInfo::initCOFFMCObjectFileInfo(Triple T) {
       ".debug_macinfo",
       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
           COFF::IMAGE_SCN_MEM_READ,
-      SectionKind::getMetadata());
+      SectionKind::getMetadata(), "debug_macinfo");
   DwarfInfoDWOSection = Ctx->getCOFFSection(
       ".debug_info.dwo",
       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |