diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 2018 |
1 files changed, 2018 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp new file mode 100644 index 0000000..3466f34 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -0,0 +1,2018 @@ +//===-- llvm/CodeGen/DwarfDebug.cpp - Dwarf Debug Framework ---------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file contains support for writing dwarf debug info into asm files. +// +//===----------------------------------------------------------------------===// + +#include "DwarfDebug.h" +#include "ByteStreamer.h" +#include "DIEHash.h" +#include "DebugLocEntry.h" +#include "DwarfCompileUnit.h" +#include "DwarfExpression.h" +#include "DwarfUnit.h" +#include "llvm/ADT/STLExtras.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/ADT/StringExtras.h" +#include "llvm/ADT/Triple.h" +#include "llvm/CodeGen/DIE.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineModuleInfo.h" +#include "llvm/IR/Constants.h" +#include "llvm/IR/DIBuilder.h" +#include "llvm/IR/DataLayout.h" +#include "llvm/IR/DebugInfo.h" +#include "llvm/IR/Instructions.h" +#include "llvm/IR/Module.h" +#include "llvm/IR/ValueHandle.h" +#include "llvm/MC/MCAsmInfo.h" +#include "llvm/MC/MCDwarf.h" +#include "llvm/MC/MCSection.h" +#include "llvm/MC/MCStreamer.h" +#include "llvm/MC/MCSymbol.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/Dwarf.h" +#include "llvm/Support/Endian.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/FormattedStream.h" +#include "llvm/Support/LEB128.h" +#include "llvm/Support/MD5.h" +#include "llvm/Support/Path.h" +#include "llvm/Support/Timer.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Target/TargetFrameLowering.h" +#include "llvm/Target/TargetLoweringObjectFile.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetOptions.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Target/TargetSubtargetInfo.h" +using namespace llvm; + +#define DEBUG_TYPE "dwarfdebug" + +static cl::opt<bool> +DisableDebugInfoPrinting("disable-debug-info-print", cl::Hidden, + cl::desc("Disable debug info printing")); + +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> +GenerateGnuPubSections("generate-gnu-dwarf-pub-sections", cl::Hidden, + cl::desc("Generate GNU-style pubnames and pubtypes"), + cl::init(false)); + +static cl::opt<bool> GenerateARangeSection("generate-arange-section", + cl::Hidden, + cl::desc("Generate dwarf aranges"), + cl::init(false)); + +namespace { +enum DefaultOnOff { Default, Enable, Disable }; +} + +static cl::opt<DefaultOnOff> +DwarfAccelTables("dwarf-accel-tables", cl::Hidden, + cl::desc("Output prototype dwarf accelerator tables."), + 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 DWARF5 split debug info."), + cl::values(clEnumVal(Default, "Default for platform"), + clEnumVal(Enable, "Enabled"), + clEnumVal(Disable, "Disabled"), clEnumValEnd), + cl::init(Default)); + +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<DefaultOnOff> +DwarfLinkageNames("dwarf-linkage-names", cl::Hidden, + cl::desc("Emit DWARF linkage-name attributes."), + cl::values(clEnumVal(Default, "Default for platform"), + clEnumVal(Enable, "Enabled"), + clEnumVal(Disable, "Disabled"), clEnumValEnd), + cl::init(Default)); + +static const char *const DWARFGroupName = "DWARF Emission"; +static const char *const DbgTimerName = "DWARF Debug Writer"; + +void DebugLocDwarfExpression::EmitOp(uint8_t Op, const char *Comment) { + BS.EmitInt8( + Op, Comment ? Twine(Comment) + " " + dwarf::OperationEncodingString(Op) + : dwarf::OperationEncodingString(Op)); +} + +void DebugLocDwarfExpression::EmitSigned(int64_t Value) { + BS.EmitSLEB128(Value, Twine(Value)); +} + +void DebugLocDwarfExpression::EmitUnsigned(uint64_t Value) { + BS.EmitULEB128(Value, Twine(Value)); +} + +bool DebugLocDwarfExpression::isFrameRegister(unsigned MachineReg) { + // This information is not available while emitting .debug_loc entries. + return false; +} + +//===----------------------------------------------------------------------===// + +/// resolve - Look in the DwarfDebug map for the MDNode that +/// corresponds to the reference. +template <typename T> T *DbgVariable::resolve(TypedDINodeRef<T> Ref) const { + return DD->resolve(Ref); +} + +bool DbgVariable::isBlockByrefVariable() const { + assert(Var && "Invalid complex DbgVariable!"); + return Var->getType() + .resolve(DD->getTypeIdentifierMap()) + ->isBlockByrefStruct(); +} + +const DIType *DbgVariable::getType() const { + DIType *Ty = Var->getType().resolve(DD->getTypeIdentifierMap()); + // FIXME: isBlockByrefVariable should be reformulated in terms of complex + // addresses instead. + if (Ty->isBlockByrefStruct()) { + /* Byref variables, in Blocks, are declared by the programmer as + "SomeType VarName;", but the compiler creates a + __Block_byref_x_VarName struct, and gives the variable VarName + either the struct, or a pointer to the struct, as its type. This + is necessary for various behind-the-scenes things the compiler + needs to do with by-reference variables in blocks. + + However, as far as the original *programmer* is concerned, the + variable should still have type 'SomeType', as originally declared. + + The following function dives into the __Block_byref_x_VarName + struct to find the original type of the variable. This will be + passed back to the code generating the type for the Debug + Information Entry for the variable 'VarName'. 'VarName' will then + have the original type 'SomeType' in its debug information. + + The original type 'SomeType' will be the type of the field named + 'VarName' inside the __Block_byref_x_VarName struct. + + NOTE: In order for this to not completely fail on the debugger + side, the Debug Information Entry for the variable VarName needs to + have a DW_AT_location that tells the debugger how to unwind through + the pointers and __Block_byref_x_VarName struct to find the actual + value of the variable. The function addBlockByrefType does this. */ + DIType *subType = Ty; + uint16_t tag = Ty->getTag(); + + if (tag == dwarf::DW_TAG_pointer_type) + subType = resolve(cast<DIDerivedType>(Ty)->getBaseType()); + + auto Elements = cast<DICompositeType>(subType)->getElements(); + for (unsigned i = 0, N = Elements.size(); i < N; ++i) { + auto *DT = cast<DIDerivedType>(Elements[i]); + if (getName() == DT->getName()) + return resolve(DT->getBaseType()); + } + } + return Ty; +} + +static LLVM_CONSTEXPR DwarfAccelTable::Atom TypeAtoms[] = { + DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, dwarf::DW_FORM_data4), + DwarfAccelTable::Atom(dwarf::DW_ATOM_die_tag, dwarf::DW_FORM_data2), + DwarfAccelTable::Atom(dwarf::DW_ATOM_type_flags, dwarf::DW_FORM_data1)}; + +DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M) + : Asm(A), MMI(Asm->MMI), DebugLocs(A->OutStreamer->isVerboseAsm()), + PrevLabel(nullptr), InfoHolder(A, "info_string", DIEValueAllocator), + SkeletonHolder(A, "skel_string", DIEValueAllocator), + IsDarwin(Triple(A->getTargetTriple()).isOSDarwin()), + AccelNames(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, + dwarf::DW_FORM_data4)), + AccelObjC(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, + dwarf::DW_FORM_data4)), + AccelNamespace(DwarfAccelTable::Atom(dwarf::DW_ATOM_die_offset, + dwarf::DW_FORM_data4)), + AccelTypes(TypeAtoms), DebuggerTuning(DebuggerKind::Default) { + + CurFn = nullptr; + CurMI = nullptr; + Triple TT(Asm->getTargetTriple()); + + // Make sure we know our "debugger tuning." The target option takes + // precedence; fall back to triple-based defaults. + if (Asm->TM.Options.DebuggerTuning != DebuggerKind::Default) + DebuggerTuning = Asm->TM.Options.DebuggerTuning; + else if (IsDarwin || TT.isOSFreeBSD()) + DebuggerTuning = DebuggerKind::LLDB; + else if (TT.isPS4CPU()) + DebuggerTuning = DebuggerKind::SCE; + else + DebuggerTuning = DebuggerKind::GDB; + + // Turn on accelerator tables for LLDB by default. + if (DwarfAccelTables == Default) + HasDwarfAccelTables = tuneForLLDB(); + else + HasDwarfAccelTables = DwarfAccelTables == Enable; + + // Handle split DWARF. Off by default for now. + if (SplitDwarf == Default) + HasSplitDwarf = false; + else + HasSplitDwarf = SplitDwarf == Enable; + + // Pubnames/pubtypes on by default for GDB. + if (DwarfPubSections == Default) + HasDwarfPubSections = tuneForGDB(); + else + HasDwarfPubSections = DwarfPubSections == Enable; + + // SCE does not use linkage names. + if (DwarfLinkageNames == Default) + UseLinkageNames = !tuneForSCE(); + else + UseLinkageNames = DwarfLinkageNames == Enable; + + unsigned DwarfVersionNumber = Asm->TM.Options.MCOptions.DwarfVersion; + DwarfVersion = DwarfVersionNumber ? DwarfVersionNumber + : MMI->getModule()->getDwarfVersion(); + // Use dwarf 4 by default if nothing is requested. + DwarfVersion = DwarfVersion ? DwarfVersion : dwarf::DWARF_VERSION; + + // Work around a GDB bug. GDB doesn't support the standard opcode; + // SCE doesn't support GNU's; LLDB prefers the standard opcode, which + // is defined as of DWARF 3. + // See GDB bug 11616 - DW_OP_form_tls_address is unimplemented + // https://sourceware.org/bugzilla/show_bug.cgi?id=11616 + UseGNUTLSOpcode = tuneForGDB() || DwarfVersion < 3; + + Asm->OutStreamer->getContext().setDwarfVersion(DwarfVersion); + + { + NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled); + beginModule(); + } +} + +// Define out of line so we don't have to include DwarfUnit.h in DwarfDebug.h. +DwarfDebug::~DwarfDebug() { } + +static bool isObjCClass(StringRef Name) { + return Name.startswith("+") || Name.startswith("-"); +} + +static bool hasObjCCategory(StringRef Name) { + if (!isObjCClass(Name)) + return false; + + return Name.find(") ") != StringRef::npos; +} + +static void getObjCClassCategory(StringRef In, StringRef &Class, + StringRef &Category) { + if (!hasObjCCategory(In)) { + Class = In.slice(In.find('[') + 1, In.find(' ')); + Category = ""; + return; + } + + Class = In.slice(In.find('[') + 1, In.find('(')); + Category = In.slice(In.find('[') + 1, In.find(' ')); + return; +} + +static StringRef getObjCMethodName(StringRef In) { + return In.slice(In.find(' ') + 1, In.find(']')); +} + +// Add the various names to the Dwarf accelerator table names. +// TODO: Determine whether or not we should add names for programs +// that do not have a DW_AT_name or DW_AT_linkage_name field - this +// is only slightly different than the lookup of non-standard ObjC names. +void DwarfDebug::addSubprogramNames(const DISubprogram *SP, DIE &Die) { + if (!SP->isDefinition()) + return; + addAccelName(SP->getName(), Die); + + // If the linkage name is different than the name, go ahead and output + // that as well into the name table. + if (SP->getLinkageName() != "" && SP->getName() != SP->getLinkageName()) + addAccelName(SP->getLinkageName(), Die); + + // If this is an Objective-C selector name add it to the ObjC accelerator + // too. + if (isObjCClass(SP->getName())) { + StringRef Class, Category; + getObjCClassCategory(SP->getName(), Class, Category); + addAccelObjC(Class, Die); + if (Category != "") + addAccelObjC(Category, Die); + // Also add the base method name to the name table. + addAccelName(getObjCMethodName(SP->getName()), Die); + } +} + +/// Check whether we should create a DIE for the given Scope, return true +/// if we don't create a DIE (the corresponding DIE is null). +bool DwarfDebug::isLexicalScopeDIENull(LexicalScope *Scope) { + if (Scope->isAbstractScope()) + return false; + + // We don't create a DIE if there is no Range. + const SmallVectorImpl<InsnRange> &Ranges = Scope->getRanges(); + if (Ranges.empty()) + return true; + + if (Ranges.size() > 1) + return false; + + // We don't create a DIE if we have a single Range and the end label + // is null. + return !getLabelAfterInsn(Ranges.front().second); +} + +template <typename Func> void forBothCUs(DwarfCompileUnit &CU, Func F) { + F(CU); + if (auto *SkelCU = CU.getSkeleton()) + F(*SkelCU); +} + +void DwarfDebug::constructAbstractSubprogramScopeDIE(LexicalScope *Scope) { + assert(Scope && Scope->getScopeNode()); + assert(Scope->isAbstractScope()); + assert(!Scope->getInlinedAt()); + + const MDNode *SP = Scope->getScopeNode(); + + ProcessedSPNodes.insert(SP); + + // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram + // was inlined from another compile unit. + auto &CU = SPMap[SP]; + forBothCUs(*CU, [&](DwarfCompileUnit &CU) { + CU.constructAbstractSubprogramScopeDIE(Scope); + }); +} + +void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const { + if (!GenerateGnuPubSections) + return; + + U.addFlag(D, dwarf::DW_AT_GNU_pubnames); +} + +// Create new DwarfCompileUnit for the given metadata node with tag +// DW_TAG_compile_unit. +DwarfCompileUnit & +DwarfDebug::constructDwarfCompileUnit(const DICompileUnit *DIUnit) { + StringRef FN = DIUnit->getFilename(); + CompilationDir = DIUnit->getDirectory(); + + auto OwnedUnit = make_unique<DwarfCompileUnit>( + InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder); + DwarfCompileUnit &NewCU = *OwnedUnit; + DIE &Die = NewCU.getUnitDie(); + InfoHolder.addUnit(std::move(OwnedUnit)); + if (useSplitDwarf()) + NewCU.setSkeleton(constructSkeletonCU(NewCU)); + + // LTO with assembly output shares a single line table amongst multiple CUs. + // To avoid the compilation directory being ambiguous, let the line table + // explicitly describe the directory of all files, never relying on the + // compilation directory. + if (!Asm->OutStreamer->hasRawTextSupport() || SingleCU) + Asm->OutStreamer->getContext().setMCLineTableCompilationDir( + NewCU.getUniqueID(), CompilationDir); + + NewCU.addString(Die, dwarf::DW_AT_producer, DIUnit->getProducer()); + NewCU.addUInt(Die, dwarf::DW_AT_language, dwarf::DW_FORM_data2, + DIUnit->getSourceLanguage()); + NewCU.addString(Die, dwarf::DW_AT_name, FN); + + if (!useSplitDwarf()) { + NewCU.initStmtList(); + + // 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); + + addGnuPubAttributes(NewCU, Die); + } + + if (DIUnit->isOptimized()) + NewCU.addFlag(Die, dwarf::DW_AT_APPLE_optimized); + + StringRef Flags = DIUnit->getFlags(); + if (!Flags.empty()) + NewCU.addString(Die, dwarf::DW_AT_APPLE_flags, Flags); + + if (unsigned RVer = DIUnit->getRuntimeVersion()) + NewCU.addUInt(Die, dwarf::DW_AT_APPLE_major_runtime_vers, + dwarf::DW_FORM_data1, RVer); + + if (useSplitDwarf()) + NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoDWOSection()); + else + NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection()); + + if (DIUnit->getDWOId()) { + // This CU is either a clang module DWO or a skeleton CU. + NewCU.addUInt(Die, dwarf::DW_AT_GNU_dwo_id, dwarf::DW_FORM_data8, + DIUnit->getDWOId()); + if (!DIUnit->getSplitDebugFilename().empty()) + // This is a prefabricated skeleton CU. + NewCU.addString(Die, dwarf::DW_AT_GNU_dwo_name, + DIUnit->getSplitDebugFilename()); + } + + CUMap.insert(std::make_pair(DIUnit, &NewCU)); + CUDieMap.insert(std::make_pair(&Die, &NewCU)); + return NewCU; +} + +void DwarfDebug::constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU, + const DIImportedEntity *N) { + if (DIE *D = TheCU.getOrCreateContextDIE(N->getScope())) + D->addChild(TheCU.constructImportedEntityDIE(N)); +} + +// Emit all Dwarf sections that should come prior to the content. Create +// global DIEs and emit initial debug info sections. This is invoked by +// the target AsmPrinter. +void DwarfDebug::beginModule() { + if (DisableDebugInfoPrinting) + return; + + const Module *M = MMI->getModule(); + + NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu"); + if (!CU_Nodes) + return; + TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes); + + SingleCU = CU_Nodes->getNumOperands() == 1; + + for (MDNode *N : CU_Nodes->operands()) { + auto *CUNode = cast<DICompileUnit>(N); + DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode); + for (auto *IE : CUNode->getImportedEntities()) + CU.addImportedEntity(IE); + for (auto *GV : CUNode->getGlobalVariables()) + CU.getOrCreateGlobalVariableDIE(GV); + for (auto *SP : CUNode->getSubprograms()) + SPMap.insert(std::make_pair(SP, &CU)); + for (auto *Ty : CUNode->getEnumTypes()) { + // The enum types array by design contains pointers to + // MDNodes rather than DIRefs. Unique them here. + CU.getOrCreateTypeDIE(cast<DIType>(resolve(Ty->getRef()))); + } + for (auto *Ty : CUNode->getRetainedTypes()) { + // The retained types array by design contains pointers to + // MDNodes rather than DIRefs. Unique them here. + DIType *RT = cast<DIType>(resolve(Ty->getRef())); + if (!RT->isExternalTypeRef()) + // There is no point in force-emitting a forward declaration. + CU.getOrCreateTypeDIE(RT); + } + // Emit imported_modules last so that the relevant context is already + // available. + for (auto *IE : CUNode->getImportedEntities()) + constructAndAddImportedEntityDIE(CU, IE); + } + + // Tell MMI that we have debug info. + MMI->setDebugInfoAvailability(true); +} + +void DwarfDebug::finishVariableDefinitions() { + for (const auto &Var : ConcreteVariables) { + DIE *VariableDie = Var->getDIE(); + assert(VariableDie); + // FIXME: Consider the time-space tradeoff of just storing the unit pointer + // in the ConcreteVariables list, rather than looking it up again here. + // DIE::getUnit isn't simple - it walks parent pointers, etc. + DwarfCompileUnit *Unit = lookupUnit(VariableDie->getUnit()); + assert(Unit); + DbgVariable *AbsVar = getExistingAbstractVariable( + InlinedVariable(Var->getVariable(), Var->getInlinedAt())); + if (AbsVar && AbsVar->getDIE()) { + Unit->addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin, + *AbsVar->getDIE()); + } else + Unit->applyVariableAttributes(*Var, *VariableDie); + } +} + +void DwarfDebug::finishSubprogramDefinitions() { + for (const auto &P : SPMap) + forBothCUs(*P.second, [&](DwarfCompileUnit &CU) { + CU.finishSubprogramDefinition(cast<DISubprogram>(P.first)); + }); +} + + +// Collect info for variables that were optimized out. +void DwarfDebug::collectDeadVariables() { + const Module *M = MMI->getModule(); + + if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) { + for (MDNode *N : CU_Nodes->operands()) { + auto *TheCU = cast<DICompileUnit>(N); + // Construct subprogram DIE and add variables DIEs. + DwarfCompileUnit *SPCU = + static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU)); + assert(SPCU && "Unable to find Compile Unit!"); + for (auto *SP : TheCU->getSubprograms()) { + if (ProcessedSPNodes.count(SP) != 0) + continue; + SPCU->collectDeadVariables(SP); + } + } + } +} + +void DwarfDebug::finalizeModuleInfo() { + const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); + + finishSubprogramDefinitions(); + + finishVariableDefinitions(); + + // Collect info for variables that were optimized out. + collectDeadVariables(); + + // Handle anything that needs to be done on a per-unit basis after + // all other generation. + for (const auto &P : CUMap) { + auto &TheCU = *P.second; + // Emit DW_AT_containing_type attribute to connect types with their + // vtable holding type. + TheCU.constructContainingTypeDIEs(); + + // Add CU specific attributes if we need to add any. + // If we're splitting the dwarf out now that we've got the entire + // CU then add the dwo id to it. + auto *SkCU = TheCU.getSkeleton(); + if (useSplitDwarf()) { + // Emit a unique identifier for this CU. + uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie()); + TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id, + dwarf::DW_FORM_data8, ID); + SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id, + dwarf::DW_FORM_data8, ID); + + // We don't keep track of which addresses are used in which CU so this + // is a bit pessimistic under LTO. + if (!AddrPool.isEmpty()) { + const MCSymbol *Sym = TLOF.getDwarfAddrSection()->getBeginSymbol(); + SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_addr_base, + Sym, Sym); + } + if (!SkCU->getRangeLists().empty()) { + const MCSymbol *Sym = TLOF.getDwarfRangesSection()->getBeginSymbol(); + SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base, + Sym, Sym); + } + } + + // If we have code split among multiple sections or non-contiguous + // ranges of code then emit a DW_AT_ranges attribute on the unit that will + // remain in the .o file, otherwise add a DW_AT_low_pc. + // FIXME: We should use ranges allow reordering of code ala + // .subsections_via_symbols in mach-o. This would mean turning on + // ranges for all subprogram DIEs for mach-o. + DwarfCompileUnit &U = SkCU ? *SkCU : TheCU; + if (unsigned NumRanges = TheCU.getRanges().size()) { + if (NumRanges > 1) + // A DW_AT_low_pc attribute may also be specified in combination with + // DW_AT_ranges to specify the default base address for use in + // location lists (see Section 2.6.2) and range lists (see Section + // 2.17.3). + U.addUInt(U.getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0); + else + U.setBaseAddress(TheCU.getRanges().front().getStart()); + U.attachRangesOrLowHighPC(U.getUnitDie(), TheCU.takeRanges()); + } + } + + // Compute DIE offsets and sizes. + InfoHolder.computeSizeAndOffsets(); + if (useSplitDwarf()) + SkeletonHolder.computeSizeAndOffsets(); +} + +// Emit all Dwarf sections that should come after the content. +void DwarfDebug::endModule() { + assert(CurFn == nullptr); + assert(CurMI == nullptr); + + // If we aren't actually generating debug info (check beginModule - + // conditionalized on !DisableDebugInfoPrinting and the presence of the + // llvm.dbg.cu metadata node) + if (!MMI->hasDebugInfo()) + return; + + // Finalize the debug info for the module. + finalizeModuleInfo(); + + emitDebugStr(); + + if (useSplitDwarf()) + emitDebugLocDWO(); + else + // Emit info into a debug loc section. + emitDebugLoc(); + + // Corresponding abbreviations into a abbrev section. + emitAbbreviations(); + + // Emit all the DIEs into a debug info section. + emitDebugInfo(); + + // Emit info into a debug aranges section. + if (GenerateARangeSection) + emitDebugARanges(); + + // Emit info into a debug ranges section. + emitDebugRanges(); + + if (useSplitDwarf()) { + emitDebugStrDWO(); + emitDebugInfoDWO(); + emitDebugAbbrevDWO(); + emitDebugLineDWO(); + // Emit DWO addresses. + AddrPool.emit(*Asm, Asm->getObjFileLowering().getDwarfAddrSection()); + } + + // Emit info into the dwarf accelerator table sections. + if (useDwarfAccelTables()) { + emitAccelNames(); + emitAccelObjC(); + emitAccelNamespaces(); + emitAccelTypes(); + } + + // Emit the pubnames and pubtypes sections if requested. + if (HasDwarfPubSections) { + emitDebugPubNames(GenerateGnuPubSections); + emitDebugPubTypes(GenerateGnuPubSections); + } + + // clean up. + SPMap.clear(); + AbstractVariables.clear(); +} + +// Find abstract variable, if any, associated with Var. +DbgVariable * +DwarfDebug::getExistingAbstractVariable(InlinedVariable IV, + const DILocalVariable *&Cleansed) { + // More then one inlined variable corresponds to one abstract variable. + Cleansed = IV.first; + auto I = AbstractVariables.find(Cleansed); + if (I != AbstractVariables.end()) + return I->second.get(); + return nullptr; +} + +DbgVariable *DwarfDebug::getExistingAbstractVariable(InlinedVariable IV) { + const DILocalVariable *Cleansed; + return getExistingAbstractVariable(IV, Cleansed); +} + +void DwarfDebug::createAbstractVariable(const DILocalVariable *Var, + LexicalScope *Scope) { + auto AbsDbgVariable = make_unique<DbgVariable>(Var, /* IA */ nullptr, this); + InfoHolder.addScopeVariable(Scope, AbsDbgVariable.get()); + AbstractVariables[Var] = std::move(AbsDbgVariable); +} + +void DwarfDebug::ensureAbstractVariableIsCreated(InlinedVariable IV, + const MDNode *ScopeNode) { + const DILocalVariable *Cleansed = nullptr; + if (getExistingAbstractVariable(IV, Cleansed)) + return; + + createAbstractVariable(Cleansed, LScopes.getOrCreateAbstractScope( + cast<DILocalScope>(ScopeNode))); +} + +void DwarfDebug::ensureAbstractVariableIsCreatedIfScoped( + InlinedVariable IV, const MDNode *ScopeNode) { + const DILocalVariable *Cleansed = nullptr; + if (getExistingAbstractVariable(IV, Cleansed)) + return; + + if (LexicalScope *Scope = + LScopes.findAbstractScope(cast_or_null<DILocalScope>(ScopeNode))) + createAbstractVariable(Cleansed, Scope); +} + +// Collect variable information from side table maintained by MMI. +void DwarfDebug::collectVariableInfoFromMMITable( + DenseSet<InlinedVariable> &Processed) { + for (const auto &VI : MMI->getVariableDbgInfo()) { + if (!VI.Var) + continue; + assert(VI.Var->isValidLocationForIntrinsic(VI.Loc) && + "Expected inlined-at fields to agree"); + + InlinedVariable Var(VI.Var, VI.Loc->getInlinedAt()); + Processed.insert(Var); + LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc); + + // If variable scope is not found then skip this variable. + if (!Scope) + continue; + + ensureAbstractVariableIsCreatedIfScoped(Var, Scope->getScopeNode()); + auto RegVar = make_unique<DbgVariable>(Var.first, Var.second, this); + RegVar->initializeMMI(VI.Expr, VI.Slot); + if (InfoHolder.addScopeVariable(Scope, RegVar.get())) + ConcreteVariables.push_back(std::move(RegVar)); + } +} + +// Get .debug_loc entry for the instruction range starting at MI. +static DebugLocEntry::Value getDebugLocValue(const MachineInstr *MI) { + const DIExpression *Expr = MI->getDebugExpression(); + + assert(MI->getNumOperands() == 4); + if (MI->getOperand(0).isReg()) { + MachineLocation MLoc; + // If the second operand is an immediate, this is a + // register-indirect address. + if (!MI->getOperand(1).isImm()) + MLoc.set(MI->getOperand(0).getReg()); + else + MLoc.set(MI->getOperand(0).getReg(), MI->getOperand(1).getImm()); + return DebugLocEntry::Value(Expr, MLoc); + } + if (MI->getOperand(0).isImm()) + return DebugLocEntry::Value(Expr, MI->getOperand(0).getImm()); + if (MI->getOperand(0).isFPImm()) + return DebugLocEntry::Value(Expr, MI->getOperand(0).getFPImm()); + if (MI->getOperand(0).isCImm()) + return DebugLocEntry::Value(Expr, MI->getOperand(0).getCImm()); + + llvm_unreachable("Unexpected 4-operand DBG_VALUE instruction!"); +} + +/// Determine whether two variable pieces overlap. +static bool piecesOverlap(const DIExpression *P1, const DIExpression *P2) { + if (!P1->isBitPiece() || !P2->isBitPiece()) + return true; + unsigned l1 = P1->getBitPieceOffset(); + unsigned l2 = P2->getBitPieceOffset(); + unsigned r1 = l1 + P1->getBitPieceSize(); + unsigned r2 = l2 + P2->getBitPieceSize(); + // True where [l1,r1[ and [r1,r2[ overlap. + return (l1 < r2) && (l2 < r1); +} + +/// Build the location list for all DBG_VALUEs in the function that +/// describe the same variable. If the ranges of several independent +/// pieces of the same variable overlap partially, split them up and +/// combine the ranges. The resulting DebugLocEntries are will have +/// strict monotonically increasing begin addresses and will never +/// overlap. +// +// Input: +// +// Ranges History [var, loc, piece ofs size] +// 0 | [x, (reg0, piece 0, 32)] +// 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry +// 2 | | ... +// 3 | [clobber reg0] +// 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of +// x. +// +// Output: +// +// [0-1] [x, (reg0, piece 0, 32)] +// [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)] +// [3-4] [x, (reg1, piece 32, 32)] +// [4- ] [x, (mem, piece 0, 64)] +void +DwarfDebug::buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc, + const DbgValueHistoryMap::InstrRanges &Ranges) { + SmallVector<DebugLocEntry::Value, 4> OpenRanges; + + for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) { + const MachineInstr *Begin = I->first; + const MachineInstr *End = I->second; + assert(Begin->isDebugValue() && "Invalid History entry"); + + // Check if a variable is inaccessible in this range. + if (Begin->getNumOperands() > 1 && + Begin->getOperand(0).isReg() && !Begin->getOperand(0).getReg()) { + OpenRanges.clear(); + continue; + } + + // If this piece overlaps with any open ranges, truncate them. + const DIExpression *DIExpr = Begin->getDebugExpression(); + auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(), + [&](DebugLocEntry::Value R) { + return piecesOverlap(DIExpr, R.getExpression()); + }); + OpenRanges.erase(Last, OpenRanges.end()); + + const MCSymbol *StartLabel = getLabelBeforeInsn(Begin); + assert(StartLabel && "Forgot label before DBG_VALUE starting a range!"); + + const MCSymbol *EndLabel; + if (End != nullptr) + EndLabel = getLabelAfterInsn(End); + else if (std::next(I) == Ranges.end()) + EndLabel = Asm->getFunctionEnd(); + else + EndLabel = getLabelBeforeInsn(std::next(I)->first); + assert(EndLabel && "Forgot label after instruction ending a range!"); + + DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n"); + + auto Value = getDebugLocValue(Begin); + DebugLocEntry Loc(StartLabel, EndLabel, Value); + bool couldMerge = false; + + // If this is a piece, it may belong to the current DebugLocEntry. + if (DIExpr->isBitPiece()) { + // Add this value to the list of open ranges. + OpenRanges.push_back(Value); + + // Attempt to add the piece to the last entry. + if (!DebugLoc.empty()) + if (DebugLoc.back().MergeValues(Loc)) + couldMerge = true; + } + + if (!couldMerge) { + // Need to add a new DebugLocEntry. Add all values from still + // valid non-overlapping pieces. + if (OpenRanges.size()) + Loc.addValues(OpenRanges); + + DebugLoc.push_back(std::move(Loc)); + } + + // Attempt to coalesce the ranges of two otherwise identical + // DebugLocEntries. + auto CurEntry = DebugLoc.rbegin(); + DEBUG({ + dbgs() << CurEntry->getValues().size() << " Values:\n"; + for (auto &Value : CurEntry->getValues()) + Value.getExpression()->dump(); + dbgs() << "-----\n"; + }); + + auto PrevEntry = std::next(CurEntry); + if (PrevEntry != DebugLoc.rend() && PrevEntry->MergeRanges(*CurEntry)) + DebugLoc.pop_back(); + } +} + +DbgVariable *DwarfDebug::createConcreteVariable(LexicalScope &Scope, + InlinedVariable IV) { + ensureAbstractVariableIsCreatedIfScoped(IV, Scope.getScopeNode()); + ConcreteVariables.push_back( + make_unique<DbgVariable>(IV.first, IV.second, this)); + InfoHolder.addScopeVariable(&Scope, ConcreteVariables.back().get()); + return ConcreteVariables.back().get(); +} + +// Find variables for each lexical scope. +void DwarfDebug::collectVariableInfo(DwarfCompileUnit &TheCU, + const DISubprogram *SP, + DenseSet<InlinedVariable> &Processed) { + // Grab the variable info that was squirreled away in the MMI side-table. + collectVariableInfoFromMMITable(Processed); + + for (const auto &I : DbgValues) { + InlinedVariable IV = I.first; + if (Processed.count(IV)) + continue; + + // Instruction ranges, specifying where IV is accessible. + const auto &Ranges = I.second; + if (Ranges.empty()) + continue; + + LexicalScope *Scope = nullptr; + if (const DILocation *IA = IV.second) + Scope = LScopes.findInlinedScope(IV.first->getScope(), IA); + else + Scope = LScopes.findLexicalScope(IV.first->getScope()); + // If variable scope is not found then skip this variable. + if (!Scope) + continue; + + Processed.insert(IV); + DbgVariable *RegVar = createConcreteVariable(*Scope, IV); + + const MachineInstr *MInsn = Ranges.front().first; + assert(MInsn->isDebugValue() && "History must begin with debug value"); + + // Check if the first DBG_VALUE is valid for the rest of the function. + if (Ranges.size() == 1 && Ranges.front().second == nullptr) { + RegVar->initializeDbgValue(MInsn); + continue; + } + + // Handle multiple DBG_VALUE instructions describing one variable. + DebugLocStream::ListBuilder List(DebugLocs, TheCU, *Asm, *RegVar, *MInsn); + + // Build the location list for this variable. + SmallVector<DebugLocEntry, 8> Entries; + buildLocationList(Entries, Ranges); + + // If the variable has an DIBasicType, extract it. Basic types cannot have + // unique identifiers, so don't bother resolving the type with the + // identifier map. + const DIBasicType *BT = dyn_cast<DIBasicType>( + static_cast<const Metadata *>(IV.first->getType())); + + // Finalize the entry by lowering it into a DWARF bytestream. + for (auto &Entry : Entries) + Entry.finalize(*Asm, List, BT); + } + + // Collect info for variables that were optimized out. + for (const DILocalVariable *DV : SP->getVariables()) { + if (Processed.insert(InlinedVariable(DV, nullptr)).second) + if (LexicalScope *Scope = LScopes.findLexicalScope(DV->getScope())) + createConcreteVariable(*Scope, InlinedVariable(DV, nullptr)); + } +} + +// Return Label preceding the instruction. +MCSymbol *DwarfDebug::getLabelBeforeInsn(const MachineInstr *MI) { + MCSymbol *Label = LabelsBeforeInsn.lookup(MI); + assert(Label && "Didn't insert label before instruction"); + return Label; +} + +// Return Label immediately following the instruction. +MCSymbol *DwarfDebug::getLabelAfterInsn(const MachineInstr *MI) { + return LabelsAfterInsn.lookup(MI); +} + +// Process beginning of an instruction. +void DwarfDebug::beginInstruction(const MachineInstr *MI) { + assert(CurMI == nullptr); + CurMI = MI; + // Check if source location changes, but ignore DBG_VALUE locations. + if (!MI->isDebugValue()) { + DebugLoc DL = MI->getDebugLoc(); + if (DL != PrevInstLoc) { + if (DL) { + unsigned Flags = 0; + PrevInstLoc = DL; + if (DL == PrologEndLoc) { + Flags |= DWARF2_FLAG_PROLOGUE_END; + PrologEndLoc = DebugLoc(); + Flags |= DWARF2_FLAG_IS_STMT; + } + if (DL.getLine() != + Asm->OutStreamer->getContext().getCurrentDwarfLoc().getLine()) + Flags |= DWARF2_FLAG_IS_STMT; + + const MDNode *Scope = DL.getScope(); + recordSourceLine(DL.getLine(), DL.getCol(), Scope, Flags); + } else if (UnknownLocations) { + PrevInstLoc = DL; + recordSourceLine(0, 0, nullptr, 0); + } + } + } + + // Insert labels where requested. + DenseMap<const MachineInstr *, MCSymbol *>::iterator I = + LabelsBeforeInsn.find(MI); + + // No label needed. + if (I == LabelsBeforeInsn.end()) + return; + + // Label already assigned. + if (I->second) + return; + + if (!PrevLabel) { + PrevLabel = MMI->getContext().createTempSymbol(); + Asm->OutStreamer->EmitLabel(PrevLabel); + } + I->second = PrevLabel; +} + +// Process end of an instruction. +void DwarfDebug::endInstruction() { + assert(CurMI != nullptr); + // Don't create a new label after DBG_VALUE instructions. + // They don't generate code. + if (!CurMI->isDebugValue()) + PrevLabel = nullptr; + + DenseMap<const MachineInstr *, MCSymbol *>::iterator I = + LabelsAfterInsn.find(CurMI); + CurMI = nullptr; + + // No label needed. + if (I == LabelsAfterInsn.end()) + return; + + // Label already assigned. + if (I->second) + return; + + // We need a label after this instruction. + if (!PrevLabel) { + PrevLabel = MMI->getContext().createTempSymbol(); + Asm->OutStreamer->EmitLabel(PrevLabel); + } + I->second = PrevLabel; +} + +// Each LexicalScope has first instruction and last instruction to mark +// beginning and end of a scope respectively. Create an inverse map that list +// scopes starts (and ends) with an instruction. One instruction may start (or +// end) multiple scopes. Ignore scopes that are not reachable. +void DwarfDebug::identifyScopeMarkers() { + SmallVector<LexicalScope *, 4> WorkList; + WorkList.push_back(LScopes.getCurrentFunctionScope()); + while (!WorkList.empty()) { + LexicalScope *S = WorkList.pop_back_val(); + + const SmallVectorImpl<LexicalScope *> &Children = S->getChildren(); + if (!Children.empty()) + WorkList.append(Children.begin(), Children.end()); + + if (S->isAbstractScope()) + continue; + + for (const InsnRange &R : S->getRanges()) { + assert(R.first && "InsnRange does not have first instruction!"); + assert(R.second && "InsnRange does not have second instruction!"); + requestLabelBeforeInsn(R.first); + requestLabelAfterInsn(R.second); + } + } +} + +static DebugLoc findPrologueEndLoc(const MachineFunction *MF) { + // First known non-DBG_VALUE and non-frame setup location marks + // the beginning of the function body. + for (const auto &MBB : *MF) + for (const auto &MI : MBB) + if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) && + MI.getDebugLoc()) + return MI.getDebugLoc(); + return DebugLoc(); +} + +// Gather pre-function debug information. Assumes being called immediately +// after the function entry point has been emitted. +void DwarfDebug::beginFunction(const MachineFunction *MF) { + CurFn = MF; + + // If there's no debug info for the function we're not going to do anything. + if (!MMI->hasDebugInfo()) + return; + + auto DI = MF->getFunction()->getSubprogram(); + if (!DI) + return; + + // Grab the lexical scopes for the function, if we don't have any of those + // then we're not going to be able to do anything. + LScopes.initialize(*MF); + if (LScopes.empty()) + return; + + assert(DbgValues.empty() && "DbgValues map wasn't cleaned!"); + + // Make sure that each lexical scope will have a begin/end label. + identifyScopeMarkers(); + + // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function + // belongs to so that we add to the correct per-cu line table in the + // non-asm case. + LexicalScope *FnScope = LScopes.getCurrentFunctionScope(); + // FnScope->getScopeNode() and DI->second should represent the same function, + // though they may not be the same MDNode due to inline functions merged in + // LTO where the debug info metadata still differs (either due to distinct + // written differences - two versions of a linkonce_odr function + // written/copied into two separate files, or some sub-optimal metadata that + // isn't structurally identical (see: file path/name info from clang, which + // includes the directory of the cpp file being built, even when the file name + // is absolute (such as an <> lookup header))) + DwarfCompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode()); + assert(TheCU && "Unable to find compile unit!"); + if (Asm->OutStreamer->hasRawTextSupport()) + // Use a single line table if we are generating assembly. + Asm->OutStreamer->getContext().setDwarfCompileUnitID(0); + else + Asm->OutStreamer->getContext().setDwarfCompileUnitID(TheCU->getUniqueID()); + + // Calculate history for local variables. + calculateDbgValueHistory(MF, Asm->MF->getSubtarget().getRegisterInfo(), + DbgValues); + + // Request labels for the full history. + for (const auto &I : DbgValues) { + const auto &Ranges = I.second; + if (Ranges.empty()) + continue; + + // The first mention of a function argument gets the CurrentFnBegin + // label, so arguments are visible when breaking at function entry. + const DILocalVariable *DIVar = Ranges.front().first->getDebugVariable(); + if (DIVar->isParameter() && + getDISubprogram(DIVar->getScope())->describes(MF->getFunction())) { + LabelsBeforeInsn[Ranges.front().first] = Asm->getFunctionBegin(); + if (Ranges.front().first->getDebugExpression()->isBitPiece()) { + // Mark all non-overlapping initial pieces. + for (auto I = Ranges.begin(); I != Ranges.end(); ++I) { + const DIExpression *Piece = I->first->getDebugExpression(); + if (std::all_of(Ranges.begin(), I, + [&](DbgValueHistoryMap::InstrRange Pred) { + return !piecesOverlap(Piece, Pred.first->getDebugExpression()); + })) + LabelsBeforeInsn[I->first] = Asm->getFunctionBegin(); + else + break; + } + } + } + + for (const auto &Range : Ranges) { + requestLabelBeforeInsn(Range.first); + if (Range.second) + requestLabelAfterInsn(Range.second); + } + } + + PrevInstLoc = DebugLoc(); + PrevLabel = Asm->getFunctionBegin(); + + // Record beginning of function. + PrologEndLoc = findPrologueEndLoc(MF); + if (DILocation *L = PrologEndLoc) { + // We'd like to list the prologue as "not statements" but GDB behaves + // poorly if we do that. Revisit this with caution/GDB (7.5+) testing. + auto *SP = L->getInlinedAtScope()->getSubprogram(); + recordSourceLine(SP->getScopeLine(), 0, SP, DWARF2_FLAG_IS_STMT); + } +} + +// Gather and emit post-function debug information. +void DwarfDebug::endFunction(const MachineFunction *MF) { + assert(CurFn == MF && + "endFunction should be called with the same function as beginFunction"); + + if (!MMI->hasDebugInfo() || LScopes.empty() || + !MF->getFunction()->getSubprogram()) { + // If we don't have a lexical scope for this function then there will + // be a hole in the range information. Keep note of this by setting the + // previously used section to nullptr. + PrevCU = nullptr; + CurFn = nullptr; + return; + } + + // Set DwarfDwarfCompileUnitID in MCContext to default value. + Asm->OutStreamer->getContext().setDwarfCompileUnitID(0); + + LexicalScope *FnScope = LScopes.getCurrentFunctionScope(); + auto *SP = cast<DISubprogram>(FnScope->getScopeNode()); + DwarfCompileUnit &TheCU = *SPMap.lookup(SP); + + DenseSet<InlinedVariable> ProcessedVars; + collectVariableInfo(TheCU, SP, ProcessedVars); + + // Add the range of this function to the list of ranges for the CU. + TheCU.addRange(RangeSpan(Asm->getFunctionBegin(), Asm->getFunctionEnd())); + + // Under -gmlt, skip building the subprogram if there are no inlined + // subroutines inside it. + if (TheCU.getCUNode()->getEmissionKind() == DIBuilder::LineTablesOnly && + LScopes.getAbstractScopesList().empty() && !IsDarwin) { + assert(InfoHolder.getScopeVariables().empty()); + assert(DbgValues.empty()); + // FIXME: This wouldn't be true in LTO with a -g (with inlining) CU followed + // by a -gmlt CU. Add a test and remove this assertion. + assert(AbstractVariables.empty()); + LabelsBeforeInsn.clear(); + LabelsAfterInsn.clear(); + PrevLabel = nullptr; + CurFn = nullptr; + return; + } + +#ifndef NDEBUG + size_t NumAbstractScopes = LScopes.getAbstractScopesList().size(); +#endif + // Construct abstract scopes. + for (LexicalScope *AScope : LScopes.getAbstractScopesList()) { + auto *SP = cast<DISubprogram>(AScope->getScopeNode()); + // Collect info for variables that were optimized out. + for (const DILocalVariable *DV : SP->getVariables()) { + if (!ProcessedVars.insert(InlinedVariable(DV, nullptr)).second) + continue; + ensureAbstractVariableIsCreated(InlinedVariable(DV, nullptr), + DV->getScope()); + assert(LScopes.getAbstractScopesList().size() == NumAbstractScopes + && "ensureAbstractVariableIsCreated inserted abstract scopes"); + } + constructAbstractSubprogramScopeDIE(AScope); + } + + TheCU.constructSubprogramScopeDIE(FnScope); + if (auto *SkelCU = TheCU.getSkeleton()) + if (!LScopes.getAbstractScopesList().empty()) + SkelCU->constructSubprogramScopeDIE(FnScope); + + // Clear debug info + // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the + // DbgVariables except those that are also in AbstractVariables (since they + // can be used cross-function) + InfoHolder.getScopeVariables().clear(); + DbgValues.clear(); + LabelsBeforeInsn.clear(); + LabelsAfterInsn.clear(); + PrevLabel = nullptr; + CurFn = nullptr; +} + +// Register a source line with debug info. Returns the unique label that was +// emitted and which provides correspondence to the source line list. +void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S, + unsigned Flags) { + StringRef Fn; + StringRef Dir; + unsigned Src = 1; + unsigned Discriminator = 0; + if (auto *Scope = cast_or_null<DIScope>(S)) { + Fn = Scope->getFilename(); + Dir = Scope->getDirectory(); + if (auto *LBF = dyn_cast<DILexicalBlockFile>(Scope)) + Discriminator = LBF->getDiscriminator(); + + unsigned CUID = Asm->OutStreamer->getContext().getDwarfCompileUnitID(); + Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID]) + .getOrCreateSourceID(Fn, Dir); + } + Asm->OutStreamer->EmitDwarfLocDirective(Src, Line, Col, Flags, 0, + Discriminator, Fn); +} + +//===----------------------------------------------------------------------===// +// Emit Methods +//===----------------------------------------------------------------------===// + +// Emit the debug info section. +void DwarfDebug::emitDebugInfo() { + DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder; + Holder.emitUnits(/* UseOffsets */ false); +} + +// Emit the abbreviation section. +void DwarfDebug::emitAbbreviations() { + DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder; + + Holder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevSection()); +} + +void DwarfDebug::emitAccel(DwarfAccelTable &Accel, MCSection *Section, + StringRef TableName) { + Accel.FinalizeTable(Asm, TableName); + Asm->OutStreamer->SwitchSection(Section); + + // Emit the full data. + Accel.emit(Asm, Section->getBeginSymbol(), this); +} + +// Emit visible names into a hashed accelerator table section. +void DwarfDebug::emitAccelNames() { + emitAccel(AccelNames, Asm->getObjFileLowering().getDwarfAccelNamesSection(), + "Names"); +} + +// Emit objective C classes and categories into a hashed accelerator table +// section. +void DwarfDebug::emitAccelObjC() { + emitAccel(AccelObjC, Asm->getObjFileLowering().getDwarfAccelObjCSection(), + "ObjC"); +} + +// Emit namespace dies into a hashed accelerator table. +void DwarfDebug::emitAccelNamespaces() { + emitAccel(AccelNamespace, + Asm->getObjFileLowering().getDwarfAccelNamespaceSection(), + "namespac"); +} + +// Emit type dies into a hashed accelerator table. +void DwarfDebug::emitAccelTypes() { + emitAccel(AccelTypes, Asm->getObjFileLowering().getDwarfAccelTypesSection(), + "types"); +} + +// Public name handling. +// The format for the various pubnames: +// +// dwarf pubnames - offset/name pairs where the offset is the offset into the CU +// for the DIE that is named. +// +// gnu pubnames - offset/index value/name tuples where the offset is the offset +// into the CU and the index value is computed according to the type of value +// for the DIE that is named. +// +// For type units the offset is the offset of the skeleton DIE. For split dwarf +// it's the offset within the debug_info/debug_types dwo section, however, the +// reference in the pubname header doesn't change. + +/// computeIndexValue - Compute the gdb index value for the DIE and CU. +static dwarf::PubIndexEntryDescriptor computeIndexValue(DwarfUnit *CU, + const DIE *Die) { + dwarf::GDBIndexEntryLinkage Linkage = dwarf::GIEL_STATIC; + + // We could have a specification DIE that has our most of our knowledge, + // look for that now. + if (DIEValue SpecVal = Die->findAttribute(dwarf::DW_AT_specification)) { + DIE &SpecDIE = SpecVal.getDIEEntry().getEntry(); + if (SpecDIE.findAttribute(dwarf::DW_AT_external)) + Linkage = dwarf::GIEL_EXTERNAL; + } else if (Die->findAttribute(dwarf::DW_AT_external)) + Linkage = dwarf::GIEL_EXTERNAL; + + switch (Die->getTag()) { + case dwarf::DW_TAG_class_type: + case dwarf::DW_TAG_structure_type: + case dwarf::DW_TAG_union_type: + case dwarf::DW_TAG_enumeration_type: + return dwarf::PubIndexEntryDescriptor( + dwarf::GIEK_TYPE, CU->getLanguage() != dwarf::DW_LANG_C_plus_plus + ? dwarf::GIEL_STATIC + : dwarf::GIEL_EXTERNAL); + case dwarf::DW_TAG_typedef: + case dwarf::DW_TAG_base_type: + case dwarf::DW_TAG_subrange_type: + return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_TYPE, dwarf::GIEL_STATIC); + case dwarf::DW_TAG_namespace: + return dwarf::GIEK_TYPE; + case dwarf::DW_TAG_subprogram: + return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_FUNCTION, Linkage); + case dwarf::DW_TAG_variable: + return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, Linkage); + case dwarf::DW_TAG_enumerator: + return dwarf::PubIndexEntryDescriptor(dwarf::GIEK_VARIABLE, + dwarf::GIEL_STATIC); + default: + return dwarf::GIEK_NONE; + } +} + +/// emitDebugPubNames - Emit visible names into a debug pubnames section. +/// +void DwarfDebug::emitDebugPubNames(bool GnuStyle) { + MCSection *PSec = GnuStyle + ? Asm->getObjFileLowering().getDwarfGnuPubNamesSection() + : Asm->getObjFileLowering().getDwarfPubNamesSection(); + + emitDebugPubSection(GnuStyle, PSec, "Names", + &DwarfCompileUnit::getGlobalNames); +} + +void DwarfDebug::emitDebugPubSection( + bool GnuStyle, MCSection *PSec, StringRef Name, + const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const) { + for (const auto &NU : CUMap) { + DwarfCompileUnit *TheU = NU.second; + + const auto &Globals = (TheU->*Accessor)(); + + if (Globals.empty()) + continue; + + if (auto *Skeleton = TheU->getSkeleton()) + TheU = Skeleton; + + // Start the dwarf pubnames section. + Asm->OutStreamer->SwitchSection(PSec); + + // Emit the header. + Asm->OutStreamer->AddComment("Length of Public " + Name + " Info"); + MCSymbol *BeginLabel = Asm->createTempSymbol("pub" + Name + "_begin"); + MCSymbol *EndLabel = Asm->createTempSymbol("pub" + Name + "_end"); + Asm->EmitLabelDifference(EndLabel, BeginLabel, 4); + + Asm->OutStreamer->EmitLabel(BeginLabel); + + Asm->OutStreamer->AddComment("DWARF Version"); + Asm->EmitInt16(dwarf::DW_PUBNAMES_VERSION); + + Asm->OutStreamer->AddComment("Offset of Compilation Unit Info"); + Asm->emitDwarfSymbolReference(TheU->getLabelBegin()); + + Asm->OutStreamer->AddComment("Compilation Unit Length"); + Asm->EmitInt32(TheU->getLength()); + + // Emit the pubnames for this compilation unit. + for (const auto &GI : Globals) { + const char *Name = GI.getKeyData(); + const DIE *Entity = GI.second; + + Asm->OutStreamer->AddComment("DIE offset"); + Asm->EmitInt32(Entity->getOffset()); + + if (GnuStyle) { + dwarf::PubIndexEntryDescriptor Desc = computeIndexValue(TheU, Entity); + Asm->OutStreamer->AddComment( + Twine("Kind: ") + dwarf::GDBIndexEntryKindString(Desc.Kind) + ", " + + dwarf::GDBIndexEntryLinkageString(Desc.Linkage)); + Asm->EmitInt8(Desc.toBits()); + } + + Asm->OutStreamer->AddComment("External Name"); + Asm->OutStreamer->EmitBytes(StringRef(Name, GI.getKeyLength() + 1)); + } + + Asm->OutStreamer->AddComment("End Mark"); + Asm->EmitInt32(0); + Asm->OutStreamer->EmitLabel(EndLabel); + } +} + +void DwarfDebug::emitDebugPubTypes(bool GnuStyle) { + MCSection *PSec = GnuStyle + ? Asm->getObjFileLowering().getDwarfGnuPubTypesSection() + : Asm->getObjFileLowering().getDwarfPubTypesSection(); + + emitDebugPubSection(GnuStyle, PSec, "Types", + &DwarfCompileUnit::getGlobalTypes); +} + +// Emit visible names into a debug str section. +void DwarfDebug::emitDebugStr() { + DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder; + Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection()); +} + +void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer, + const DebugLocStream::Entry &Entry) { + auto &&Comments = DebugLocs.getComments(Entry); + auto Comment = Comments.begin(); + auto End = Comments.end(); + for (uint8_t Byte : DebugLocs.getBytes(Entry)) + Streamer.EmitInt8(Byte, Comment != End ? *(Comment++) : ""); +} + +static void emitDebugLocValue(const AsmPrinter &AP, const DIBasicType *BT, + ByteStreamer &Streamer, + const DebugLocEntry::Value &Value, + unsigned PieceOffsetInBits) { + DebugLocDwarfExpression DwarfExpr(*AP.MF->getSubtarget().getRegisterInfo(), + AP.getDwarfDebug()->getDwarfVersion(), + Streamer); + // Regular entry. + if (Value.isInt()) { + if (BT && (BT->getEncoding() == dwarf::DW_ATE_signed || + BT->getEncoding() == dwarf::DW_ATE_signed_char)) + DwarfExpr.AddSignedConstant(Value.getInt()); + else + DwarfExpr.AddUnsignedConstant(Value.getInt()); + } else if (Value.isLocation()) { + MachineLocation Loc = Value.getLoc(); + const DIExpression *Expr = Value.getExpression(); + if (!Expr || !Expr->getNumElements()) + // Regular entry. + AP.EmitDwarfRegOp(Streamer, Loc); + else { + // Complex address entry. + if (Loc.getOffset()) { + DwarfExpr.AddMachineRegIndirect(Loc.getReg(), Loc.getOffset()); + DwarfExpr.AddExpression(Expr->expr_op_begin(), Expr->expr_op_end(), + PieceOffsetInBits); + } else + DwarfExpr.AddMachineRegExpression(Expr, Loc.getReg(), + PieceOffsetInBits); + } + } + // else ... ignore constant fp. There is not any good way to + // to represent them here in dwarf. + // FIXME: ^ +} + +void DebugLocEntry::finalize(const AsmPrinter &AP, + DebugLocStream::ListBuilder &List, + const DIBasicType *BT) { + DebugLocStream::EntryBuilder Entry(List, Begin, End); + BufferByteStreamer Streamer = Entry.getStreamer(); + const DebugLocEntry::Value &Value = Values[0]; + if (Value.isBitPiece()) { + // Emit all pieces that belong to the same variable and range. + assert(std::all_of(Values.begin(), Values.end(), [](DebugLocEntry::Value P) { + return P.isBitPiece(); + }) && "all values are expected to be pieces"); + assert(std::is_sorted(Values.begin(), Values.end()) && + "pieces are expected to be sorted"); + + unsigned Offset = 0; + for (auto Piece : Values) { + const DIExpression *Expr = Piece.getExpression(); + unsigned PieceOffset = Expr->getBitPieceOffset(); + unsigned PieceSize = Expr->getBitPieceSize(); + assert(Offset <= PieceOffset && "overlapping or duplicate pieces"); + if (Offset < PieceOffset) { + // The DWARF spec seriously mandates pieces with no locations for gaps. + DebugLocDwarfExpression Expr(*AP.MF->getSubtarget().getRegisterInfo(), + AP.getDwarfDebug()->getDwarfVersion(), + Streamer); + Expr.AddOpPiece(PieceOffset-Offset, 0); + Offset += PieceOffset-Offset; + } + Offset += PieceSize; + + emitDebugLocValue(AP, BT, Streamer, Piece, PieceOffset); + } + } else { + assert(Values.size() == 1 && "only pieces may have >1 value"); + emitDebugLocValue(AP, BT, Streamer, Value, 0); + } +} + +void DwarfDebug::emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry) { + // Emit the size. + Asm->OutStreamer->AddComment("Loc expr size"); + Asm->EmitInt16(DebugLocs.getBytes(Entry).size()); + + // Emit the entry. + APByteStreamer Streamer(*Asm); + emitDebugLocEntry(Streamer, Entry); +} + +// Emit locations into the debug loc section. +void DwarfDebug::emitDebugLoc() { + // Start the dwarf loc section. + Asm->OutStreamer->SwitchSection( + Asm->getObjFileLowering().getDwarfLocSection()); + unsigned char Size = Asm->getDataLayout().getPointerSize(); + for (const auto &List : DebugLocs.getLists()) { + Asm->OutStreamer->EmitLabel(List.Label); + const DwarfCompileUnit *CU = List.CU; + for (const auto &Entry : DebugLocs.getEntries(List)) { + // Set up the range. This range is relative to the entry point of the + // compile unit. This is a hard coded 0 for low_pc when we're emitting + // ranges, or the DW_AT_low_pc on the compile unit otherwise. + if (auto *Base = CU->getBaseAddress()) { + Asm->EmitLabelDifference(Entry.BeginSym, Base, Size); + Asm->EmitLabelDifference(Entry.EndSym, Base, Size); + } else { + Asm->OutStreamer->EmitSymbolValue(Entry.BeginSym, Size); + Asm->OutStreamer->EmitSymbolValue(Entry.EndSym, Size); + } + + emitDebugLocEntryLocation(Entry); + } + Asm->OutStreamer->EmitIntValue(0, Size); + Asm->OutStreamer->EmitIntValue(0, Size); + } +} + +void DwarfDebug::emitDebugLocDWO() { + Asm->OutStreamer->SwitchSection( + Asm->getObjFileLowering().getDwarfLocDWOSection()); + for (const auto &List : DebugLocs.getLists()) { + Asm->OutStreamer->EmitLabel(List.Label); + for (const auto &Entry : DebugLocs.getEntries(List)) { + // Just always use start_length for now - at least that's one address + // rather than two. We could get fancier and try to, say, reuse an + // address we know we've emitted elsewhere (the start of the function? + // The start of the CU or CU subrange that encloses this range?) + Asm->EmitInt8(dwarf::DW_LLE_start_length_entry); + unsigned idx = AddrPool.getIndex(Entry.BeginSym); + Asm->EmitULEB128(idx); + Asm->EmitLabelDifference(Entry.EndSym, Entry.BeginSym, 4); + + emitDebugLocEntryLocation(Entry); + } + Asm->EmitInt8(dwarf::DW_LLE_end_of_list_entry); + } +} + +struct ArangeSpan { + const MCSymbol *Start, *End; +}; + +// Emit a debug aranges section, containing a CU lookup for any +// address we can tie back to a CU. +void DwarfDebug::emitDebugARanges() { + // Provides a unique id per text section. + MapVector<MCSection *, SmallVector<SymbolCU, 8>> SectionMap; + + // Filter labels by section. + for (const SymbolCU &SCU : ArangeLabels) { + if (SCU.Sym->isInSection()) { + // Make a note of this symbol and it's section. + MCSection *Section = &SCU.Sym->getSection(); + if (!Section->getKind().isMetadata()) + SectionMap[Section].push_back(SCU); + } else { + // Some symbols (e.g. common/bss on mach-o) can have no section but still + // appear in the output. This sucks as we rely on sections to build + // arange spans. We can do it without, but it's icky. + SectionMap[nullptr].push_back(SCU); + } + } + + // Add terminating symbols for each section. + for (const auto &I : SectionMap) { + MCSection *Section = I.first; + MCSymbol *Sym = nullptr; + + if (Section) + Sym = Asm->OutStreamer->endSection(Section); + + // Insert a final terminator. + SectionMap[Section].push_back(SymbolCU(nullptr, Sym)); + } + + DenseMap<DwarfCompileUnit *, std::vector<ArangeSpan>> Spans; + + for (auto &I : SectionMap) { + const MCSection *Section = I.first; + SmallVector<SymbolCU, 8> &List = I.second; + if (List.size() < 2) + continue; + + // If we have no section (e.g. common), just write out + // individual spans for each symbol. + if (!Section) { + for (const SymbolCU &Cur : List) { + ArangeSpan Span; + Span.Start = Cur.Sym; + Span.End = nullptr; + if (Cur.CU) + Spans[Cur.CU].push_back(Span); + } + continue; + } + + // Sort the symbols by offset within the section. + std::sort(List.begin(), List.end(), + [&](const SymbolCU &A, const SymbolCU &B) { + unsigned IA = A.Sym ? Asm->OutStreamer->GetSymbolOrder(A.Sym) : 0; + unsigned IB = B.Sym ? Asm->OutStreamer->GetSymbolOrder(B.Sym) : 0; + + // Symbols with no order assigned should be placed at the end. + // (e.g. section end labels) + if (IA == 0) + return false; + if (IB == 0) + return true; + return IA < IB; + }); + + // Build spans between each label. + const MCSymbol *StartSym = List[0].Sym; + for (size_t n = 1, e = List.size(); n < e; n++) { + const SymbolCU &Prev = List[n - 1]; + const SymbolCU &Cur = List[n]; + + // Try and build the longest span we can within the same CU. + if (Cur.CU != Prev.CU) { + ArangeSpan Span; + Span.Start = StartSym; + Span.End = Cur.Sym; + Spans[Prev.CU].push_back(Span); + StartSym = Cur.Sym; + } + } + } + + // Start the dwarf aranges section. + Asm->OutStreamer->SwitchSection( + Asm->getObjFileLowering().getDwarfARangesSection()); + + unsigned PtrSize = Asm->getDataLayout().getPointerSize(); + + // Build a list of CUs used. + std::vector<DwarfCompileUnit *> CUs; + for (const auto &it : Spans) { + DwarfCompileUnit *CU = it.first; + CUs.push_back(CU); + } + + // Sort the CU list (again, to ensure consistent output order). + std::sort(CUs.begin(), CUs.end(), [](const DwarfUnit *A, const DwarfUnit *B) { + return A->getUniqueID() < B->getUniqueID(); + }); + + // Emit an arange table for each CU we used. + for (DwarfCompileUnit *CU : CUs) { + std::vector<ArangeSpan> &List = Spans[CU]; + + // Describe the skeleton CU's offset and length, not the dwo file's. + if (auto *Skel = CU->getSkeleton()) + CU = Skel; + + // Emit size of content not including length itself. + unsigned ContentSize = + sizeof(int16_t) + // DWARF ARange version number + sizeof(int32_t) + // Offset of CU in the .debug_info section + sizeof(int8_t) + // Pointer Size (in bytes) + sizeof(int8_t); // Segment Size (in bytes) + + unsigned TupleSize = PtrSize * 2; + + // 7.20 in the Dwarf specs requires the table to be aligned to a tuple. + unsigned Padding = + OffsetToAlignment(sizeof(int32_t) + ContentSize, TupleSize); + + ContentSize += Padding; + ContentSize += (List.size() + 1) * TupleSize; + + // For each compile unit, write the list of spans it covers. + Asm->OutStreamer->AddComment("Length of ARange Set"); + Asm->EmitInt32(ContentSize); + Asm->OutStreamer->AddComment("DWARF Arange version number"); + Asm->EmitInt16(dwarf::DW_ARANGES_VERSION); + Asm->OutStreamer->AddComment("Offset Into Debug Info Section"); + Asm->emitDwarfSymbolReference(CU->getLabelBegin()); + Asm->OutStreamer->AddComment("Address Size (in bytes)"); + Asm->EmitInt8(PtrSize); + Asm->OutStreamer->AddComment("Segment Size (in bytes)"); + Asm->EmitInt8(0); + + Asm->OutStreamer->EmitFill(Padding, 0xff); + + for (const ArangeSpan &Span : List) { + Asm->EmitLabelReference(Span.Start, PtrSize); + + // Calculate the size as being from the span start to it's end. + if (Span.End) { + Asm->EmitLabelDifference(Span.End, Span.Start, PtrSize); + } else { + // For symbols without an end marker (e.g. common), we + // write a single arange entry containing just that one symbol. + uint64_t Size = SymSize[Span.Start]; + if (Size == 0) + Size = 1; + + Asm->OutStreamer->EmitIntValue(Size, PtrSize); + } + } + + Asm->OutStreamer->AddComment("ARange terminator"); + Asm->OutStreamer->EmitIntValue(0, PtrSize); + Asm->OutStreamer->EmitIntValue(0, PtrSize); + } +} + +// Emit visible names into a debug ranges section. +void DwarfDebug::emitDebugRanges() { + // Start the dwarf ranges section. + Asm->OutStreamer->SwitchSection( + Asm->getObjFileLowering().getDwarfRangesSection()); + + // Size for our labels. + unsigned char Size = Asm->getDataLayout().getPointerSize(); + + // Grab the specific ranges for the compile units in the module. + for (const auto &I : CUMap) { + DwarfCompileUnit *TheCU = I.second; + + if (auto *Skel = TheCU->getSkeleton()) + TheCU = Skel; + + // Iterate over the misc ranges for the compile units in the module. + for (const RangeSpanList &List : TheCU->getRangeLists()) { + // Emit our symbol so we can find the beginning of the range. + Asm->OutStreamer->EmitLabel(List.getSym()); + + for (const RangeSpan &Range : List.getRanges()) { + const MCSymbol *Begin = Range.getStart(); + const MCSymbol *End = Range.getEnd(); + assert(Begin && "Range without a begin symbol?"); + assert(End && "Range without an end symbol?"); + if (auto *Base = TheCU->getBaseAddress()) { + Asm->EmitLabelDifference(Begin, Base, Size); + Asm->EmitLabelDifference(End, Base, Size); + } else { + Asm->OutStreamer->EmitSymbolValue(Begin, Size); + Asm->OutStreamer->EmitSymbolValue(End, Size); + } + } + + // And terminate the list with two 0 values. + Asm->OutStreamer->EmitIntValue(0, Size); + Asm->OutStreamer->EmitIntValue(0, Size); + } + } +} + +// DWARF5 Experimental Separate Dwarf emitters. + +void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die, + std::unique_ptr<DwarfUnit> NewU) { + NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name, + U.getCUNode()->getSplitDebugFilename()); + + if (!CompilationDir.empty()) + NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir); + + addGnuPubAttributes(*NewU, Die); + + SkeletonHolder.addUnit(std::move(NewU)); +} + +// This DIE has the following attributes: DW_AT_comp_dir, DW_AT_stmt_list, +// DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges, DW_AT_dwo_name, DW_AT_dwo_id, +// DW_AT_addr_base, DW_AT_ranges_base. +DwarfCompileUnit &DwarfDebug::constructSkeletonCU(const DwarfCompileUnit &CU) { + + auto OwnedUnit = make_unique<DwarfCompileUnit>( + CU.getUniqueID(), CU.getCUNode(), Asm, this, &SkeletonHolder); + DwarfCompileUnit &NewCU = *OwnedUnit; + NewCU.initSection(Asm->getObjFileLowering().getDwarfInfoSection()); + + NewCU.initStmtList(); + + initSkeletonUnit(CU, NewCU.getUnitDie(), std::move(OwnedUnit)); + + return NewCU; +} + +// Emit the .debug_info.dwo section for separated dwarf. This contains the +// compile units that would normally be in debug_info. +void DwarfDebug::emitDebugInfoDWO() { + assert(useSplitDwarf() && "No split dwarf debug info?"); + // Don't emit relocations into the dwo file. + InfoHolder.emitUnits(/* UseOffsets */ true); +} + +// Emit the .debug_abbrev.dwo section for separated dwarf. This contains the +// abbreviations for the .debug_info.dwo section. +void DwarfDebug::emitDebugAbbrevDWO() { + assert(useSplitDwarf() && "No split dwarf?"); + InfoHolder.emitAbbrevs(Asm->getObjFileLowering().getDwarfAbbrevDWOSection()); +} + +void DwarfDebug::emitDebugLineDWO() { + assert(useSplitDwarf() && "No split dwarf?"); + Asm->OutStreamer->SwitchSection( + Asm->getObjFileLowering().getDwarfLineDWOSection()); + SplitTypeUnitFileTable.Emit(*Asm->OutStreamer, MCDwarfLineTableParams()); +} + +// Emit the .debug_str.dwo section for separated dwarf. This contains the +// string section and is identical in format to traditional .debug_str +// sections. +void DwarfDebug::emitDebugStrDWO() { + assert(useSplitDwarf() && "No split dwarf?"); + MCSection *OffSec = Asm->getObjFileLowering().getDwarfStrOffDWOSection(); + InfoHolder.emitStrings(Asm->getObjFileLowering().getDwarfStrDWOSection(), + OffSec); +} + +MCDwarfDwoLineTable *DwarfDebug::getDwoLineTable(const DwarfCompileUnit &CU) { + if (!useSplitDwarf()) + return nullptr; + if (SingleCU) + SplitTypeUnitFileTable.setCompilationDir(CU.getCUNode()->getDirectory()); + return &SplitTypeUnitFileTable; +} + +uint64_t DwarfDebug::makeTypeSignature(StringRef Identifier) { + MD5 Hash; + Hash.update(Identifier); + // ... take the least significant 8 bytes and return those. Our MD5 + // implementation always returns its results in little endian, swap bytes + // appropriately. + MD5::MD5Result Result; + Hash.final(Result); + return support::endian::read64le(Result + 8); +} + +void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU, + StringRef Identifier, DIE &RefDie, + const DICompositeType *CTy) { + // Fast path if we're building some type units and one has already used the + // address pool we know we're going to throw away all this work anyway, so + // don't bother building dependent types. + if (!TypeUnitsUnderConstruction.empty() && AddrPool.hasBeenUsed()) + return; + + const DwarfTypeUnit *&TU = DwarfTypeUnits[CTy]; + if (TU) { + CU.addDIETypeSignature(RefDie, *TU); + return; + } + + bool TopLevelType = TypeUnitsUnderConstruction.empty(); + AddrPool.resetUsedFlag(); + + 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; + TypeUnitsUnderConstruction.push_back( + std::make_pair(std::move(OwnedUnit), CTy)); + + NewTU.addUInt(UnitDie, dwarf::DW_AT_language, dwarf::DW_FORM_data2, + CU.getLanguage()); + + uint64_t Signature = makeTypeSignature(Identifier); + NewTU.setTypeSignature(Signature); + + if (useSplitDwarf()) + NewTU.initSection(Asm->getObjFileLowering().getDwarfTypesDWOSection()); + else { + CU.applyStmtList(UnitDie); + NewTU.initSection( + Asm->getObjFileLowering().getDwarfTypesSection(Signature)); + } + + NewTU.setType(NewTU.createTypeDIE(CTy)); + + if (TopLevelType) { + auto TypeUnitsToAdd = std::move(TypeUnitsUnderConstruction); + TypeUnitsUnderConstruction.clear(); + + // Types referencing entries in the address table cannot be placed in type + // units. + if (AddrPool.hasBeenUsed()) { + + // Remove all the types built while building this type. + // This is pessimistic as some of these types might not be dependent on + // the type that used an address. + for (const auto &TU : TypeUnitsToAdd) + DwarfTypeUnits.erase(TU.second); + + // Construct this type in the CU directly. + // This is inefficient because all the dependent types will be rebuilt + // from scratch, including building them in type units, discovering that + // they depend on addresses, throwing them out and rebuilding them. + CU.constructTypeDIE(RefDie, cast<DICompositeType>(CTy)); + return; + } + + // If the type wasn't dependent on fission addresses, finish adding the type + // and all its dependent types. + for (auto &TU : TypeUnitsToAdd) + InfoHolder.addUnit(std::move(TU.first)); + } + CU.addDIETypeSignature(RefDie, NewTU); +} + +// Accelerator table mutators - add each name along with its companion +// DIE to the proper table while ensuring that the name that we're going +// to reference is in the string table. We do this since the names we +// add may not only be identical to the names in the DIE. +void DwarfDebug::addAccelName(StringRef Name, const DIE &Die) { + if (!useDwarfAccelTables()) + return; + AccelNames.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die); +} + +void DwarfDebug::addAccelObjC(StringRef Name, const DIE &Die) { + if (!useDwarfAccelTables()) + return; + AccelObjC.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die); +} + +void DwarfDebug::addAccelNamespace(StringRef Name, const DIE &Die) { + if (!useDwarfAccelTables()) + return; + AccelNamespace.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die); +} + +void DwarfDebug::addAccelType(StringRef Name, const DIE &Die, char Flags) { + if (!useDwarfAccelTables()) + return; + AccelTypes.AddName(InfoHolder.getStringPool().getEntry(*Asm, Name), &Die); +} |
