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//===-- llvm/CodeGen/DwarfUnit.cpp - Dwarf Type and Compile Units ---------===//
// 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 constructing a dwarf compile unit.
#include "DwarfUnit.h"
#include "AddressPool.h"
#include "DwarfCompileUnit.h"
#include "DwarfDebug.h"
#include "DwarfExpression.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Metadata.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MachineLocation.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include <cassert>
#include <cstdint>
#include <string>
#include <utility>
using namespace llvm;
#define DEBUG_TYPE "dwarfdebug"
DIEDwarfExpression::DIEDwarfExpression(const AsmPrinter &AP, DwarfUnit &DU,
: DwarfExpression(AP.getDwarfVersion()), AP(AP), DU(DU),
void DIEDwarfExpression::emitOp(uint8_t Op, const char* Comment) {
DU.addUInt(DIE, dwarf::DW_FORM_data1, Op);
void DIEDwarfExpression::emitSigned(int64_t Value) {
DU.addSInt(DIE, dwarf::DW_FORM_sdata, Value);
void DIEDwarfExpression::emitUnsigned(uint64_t Value) {
DU.addUInt(DIE, dwarf::DW_FORM_udata, Value);
bool DIEDwarfExpression::isFrameRegister(const TargetRegisterInfo &TRI,
unsigned MachineReg) {
return MachineReg == TRI.getFrameRegister(*AP.MF);
DwarfUnit::DwarfUnit(dwarf::Tag UnitTag, const DICompileUnit *Node,
AsmPrinter *A, DwarfDebug *DW, DwarfFile *DWU)
: DIEUnit(A->getDwarfVersion(), A->MAI->getCodePointerSize(), UnitTag),
CUNode(Node), Asm(A), DD(DW), DU(DWU), IndexTyDie(nullptr) {
DwarfTypeUnit::DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A,
DwarfDebug *DW, DwarfFile *DWU,
MCDwarfDwoLineTable *SplitLineTable)
: DwarfUnit(dwarf::DW_TAG_type_unit, CU.getCUNode(), A, DW, DWU), CU(CU),
SplitLineTable(SplitLineTable) {
DwarfUnit::~DwarfUnit() {
for (unsigned j = 0, M = DIEBlocks.size(); j < M; ++j)
for (unsigned j = 0, M = DIELocs.size(); j < M; ++j)
int64_t DwarfUnit::getDefaultLowerBound() const {
switch (getLanguage()) {
// The languages below have valid values in all DWARF versions.
case dwarf::DW_LANG_C:
case dwarf::DW_LANG_C89:
case dwarf::DW_LANG_C_plus_plus:
return 0;
case dwarf::DW_LANG_Fortran77:
case dwarf::DW_LANG_Fortran90:
return 1;
// The languages below have valid values only if the DWARF version >= 3.
case dwarf::DW_LANG_C99:
case dwarf::DW_LANG_ObjC:
case dwarf::DW_LANG_ObjC_plus_plus:
if (DD->getDwarfVersion() >= 3)
return 0;
case dwarf::DW_LANG_Fortran95:
if (DD->getDwarfVersion() >= 3)
return 1;
// Starting with DWARF v4, all defined languages have valid values.
case dwarf::DW_LANG_D:
case dwarf::DW_LANG_Java:
case dwarf::DW_LANG_Python:
case dwarf::DW_LANG_UPC:
if (DD->getDwarfVersion() >= 4)
return 0;
case dwarf::DW_LANG_Ada83:
case dwarf::DW_LANG_Ada95:
case dwarf::DW_LANG_Cobol74:
case dwarf::DW_LANG_Cobol85:
case dwarf::DW_LANG_Modula2:
case dwarf::DW_LANG_Pascal83:
case dwarf::DW_LANG_PLI:
if (DD->getDwarfVersion() >= 4)
return 1;
// The languages below are new in DWARF v5.
case dwarf::DW_LANG_BLISS:
case dwarf::DW_LANG_C11:
case dwarf::DW_LANG_C_plus_plus_03:
case dwarf::DW_LANG_C_plus_plus_11:
case dwarf::DW_LANG_C_plus_plus_14:
case dwarf::DW_LANG_Dylan:
case dwarf::DW_LANG_Go:
case dwarf::DW_LANG_Haskell:
case dwarf::DW_LANG_OCaml:
case dwarf::DW_LANG_OpenCL:
case dwarf::DW_LANG_RenderScript:
case dwarf::DW_LANG_Rust:
case dwarf::DW_LANG_Swift:
if (DD->getDwarfVersion() >= 5)
return 0;
case dwarf::DW_LANG_Fortran03:
case dwarf::DW_LANG_Fortran08:
case dwarf::DW_LANG_Julia:
case dwarf::DW_LANG_Modula3:
if (DD->getDwarfVersion() >= 5)
return 1;
return -1;
/// Check whether the DIE for this MDNode can be shared across CUs.
bool DwarfUnit::isShareableAcrossCUs(const DINode *D) const {
// When the MDNode can be part of the type system, the DIE can be shared
// across CUs.
// Combining type units and cross-CU DIE sharing is lower value (since
// cross-CU DIE sharing is used in LTO and removes type redundancy at that
// level already) but may be implementable for some value in projects
// building multiple independent libraries with LTO and then linking those
// together.
if (isDwoUnit() && !DD->shareAcrossDWOCUs())
return false;
return (isa<DIType>(D) ||
(isa<DISubprogram>(D) && !cast<DISubprogram>(D)->isDefinition())) &&
DIE *DwarfUnit::getDIE(const DINode *D) const {
if (isShareableAcrossCUs(D))
return DU->getDIE(D);
return MDNodeToDieMap.lookup(D);
void DwarfUnit::insertDIE(const DINode *Desc, DIE *D) {
if (isShareableAcrossCUs(Desc)) {
DU->insertDIE(Desc, D);
MDNodeToDieMap.insert(std::make_pair(Desc, D));
void DwarfUnit::addFlag(DIE &Die, dwarf::Attribute Attribute) {
if (DD->getDwarfVersion() >= 4)
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_flag_present,
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_flag,
void DwarfUnit::addUInt(DIEValueList &Die, dwarf::Attribute Attribute,
Optional<dwarf::Form> Form, uint64_t Integer) {
if (!Form)
Form = DIEInteger::BestForm(false, Integer);
assert(Form != dwarf::DW_FORM_implicit_const &&
"DW_FORM_implicit_const is used only for signed integers");
Die.addValue(DIEValueAllocator, Attribute, *Form, DIEInteger(Integer));
void DwarfUnit::addUInt(DIEValueList &Block, dwarf::Form Form,
uint64_t Integer) {
addUInt(Block, (dwarf::Attribute)0, Form, Integer);
void DwarfUnit::addSInt(DIEValueList &Die, dwarf::Attribute Attribute,
Optional<dwarf::Form> Form, int64_t Integer) {
if (!Form)
Form = DIEInteger::BestForm(true, Integer);
Die.addValue(DIEValueAllocator, Attribute, *Form, DIEInteger(Integer));
void DwarfUnit::addSInt(DIELoc &Die, Optional<dwarf::Form> Form,
int64_t Integer) {
addSInt(Die, (dwarf::Attribute)0, Form, Integer);
void DwarfUnit::addString(DIE &Die, dwarf::Attribute Attribute,
StringRef String) {
if (CUNode->isDebugDirectivesOnly())
if (DD->useInlineStrings()) {
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_string,
new (DIEValueAllocator)
DIEInlineString(String, DIEValueAllocator));
dwarf::Form IxForm =
isDwoUnit() ? dwarf::DW_FORM_GNU_str_index : dwarf::DW_FORM_strp;
auto StringPoolEntry =
useSegmentedStringOffsetsTable() || IxForm == dwarf::DW_FORM_GNU_str_index
? DU->getStringPool().getIndexedEntry(*Asm, String)
: DU->getStringPool().getEntry(*Asm, String);
// For DWARF v5 and beyond, use the smallest strx? form possible.
if (useSegmentedStringOffsetsTable()) {
IxForm = dwarf::DW_FORM_strx1;
unsigned Index = StringPoolEntry.getIndex();
if (Index > 0xffffff)
IxForm = dwarf::DW_FORM_strx4;
else if (Index > 0xffff)
IxForm = dwarf::DW_FORM_strx3;
else if (Index > 0xff)
IxForm = dwarf::DW_FORM_strx2;
Die.addValue(DIEValueAllocator, Attribute, IxForm,
DIEValueList::value_iterator DwarfUnit::addLabel(DIEValueList &Die,
dwarf::Attribute Attribute,
dwarf::Form Form,
const MCSymbol *Label) {
return Die.addValue(DIEValueAllocator, Attribute, Form, DIELabel(Label));
void DwarfUnit::addLabel(DIELoc &Die, dwarf::Form Form, const MCSymbol *Label) {
addLabel(Die, (dwarf::Attribute)0, Form, Label);
void DwarfUnit::addSectionOffset(DIE &Die, dwarf::Attribute Attribute,
uint64_t Integer) {
if (DD->getDwarfVersion() >= 4)
addUInt(Die, Attribute, dwarf::DW_FORM_sec_offset, Integer);
addUInt(Die, Attribute, dwarf::DW_FORM_data4, Integer);
MD5::MD5Result *DwarfUnit::getMD5AsBytes(const DIFile *File) const {
if (DD->getDwarfVersion() < 5)
return nullptr;
Optional<DIFile::ChecksumInfo<StringRef>> Checksum = File->getChecksum();
if (!Checksum || Checksum->Kind != DIFile::CSK_MD5)
return nullptr;
// Convert the string checksum to an MD5Result for the streamer.
// The verifier validates the checksum so we assume it's okay.
// An MD5 checksum is 16 bytes.
std::string ChecksumString = fromHex(Checksum->Value);
void *CKMem = Asm->OutStreamer->getContext().allocate(16, 1);
memcpy(CKMem,, 16);
return reinterpret_cast<MD5::MD5Result *>(CKMem);
unsigned DwarfTypeUnit::getOrCreateSourceID(const DIFile *File) {
if (!SplitLineTable)
return getCU().getOrCreateSourceID(File);
if (!UsedLineTable) {
UsedLineTable = true;
// This is a split type unit that needs a line table.
addSectionOffset(getUnitDie(), dwarf::DW_AT_stmt_list, 0);
return SplitLineTable->getFile(File->getDirectory(), File->getFilename(),
getMD5AsBytes(File), File->getSource());
void DwarfUnit::addOpAddress(DIELoc &Die, const MCSymbol *Sym) {
if (DD->getDwarfVersion() >= 5) {
addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_addrx);
addUInt(Die, dwarf::DW_FORM_addrx, DD->getAddressPool().getIndex(Sym));
if (DD->useSplitDwarf()) {
addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_addr_index);
addUInt(Die, dwarf::DW_FORM_GNU_addr_index,
addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_addr);
addLabel(Die, dwarf::DW_FORM_udata, Sym);
void DwarfUnit::addLabelDelta(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Hi, const MCSymbol *Lo) {
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_data4,
new (DIEValueAllocator) DIEDelta(Hi, Lo));
void DwarfUnit::addDIEEntry(DIE &Die, dwarf::Attribute Attribute, DIE &Entry) {
addDIEEntry(Die, Attribute, DIEEntry(Entry));
void DwarfUnit::addDIETypeSignature(DIE &Die, uint64_t Signature) {
// Flag the type unit reference as a declaration so that if it contains
// members (implicit special members, static data member definitions, member
// declarations for definitions in this CU, etc) consumers don't get confused
// and think this is a full definition.
addFlag(Die, dwarf::DW_AT_declaration);
Die.addValue(DIEValueAllocator, dwarf::DW_AT_signature,
dwarf::DW_FORM_ref_sig8, DIEInteger(Signature));
void DwarfUnit::addDIEEntry(DIE &Die, dwarf::Attribute Attribute,
DIEEntry Entry) {
const DIEUnit *CU = Die.getUnit();
const DIEUnit *EntryCU = Entry.getEntry().getUnit();
if (!CU)
// We assume that Die belongs to this CU, if it is not linked to any CU yet.
CU = getUnitDie().getUnit();
if (!EntryCU)
EntryCU = getUnitDie().getUnit();
Die.addValue(DIEValueAllocator, Attribute,
EntryCU == CU ? dwarf::DW_FORM_ref4 : dwarf::DW_FORM_ref_addr,
DIE &DwarfUnit::createAndAddDIE(unsigned Tag, DIE &Parent, const DINode *N) {
DIE &Die = Parent.addChild(DIE::get(DIEValueAllocator, (dwarf::Tag)Tag));
if (N)
insertDIE(N, &Die);
return Die;
void DwarfUnit::addBlock(DIE &Die, dwarf::Attribute Attribute, DIELoc *Loc) {
DIELocs.push_back(Loc); // Memoize so we can call the destructor later on.
Die.addValue(DIEValueAllocator, Attribute,
Loc->BestForm(DD->getDwarfVersion()), Loc);
void DwarfUnit::addBlock(DIE &Die, dwarf::Attribute Attribute,
DIEBlock *Block) {
DIEBlocks.push_back(Block); // Memoize so we can call the destructor later on.
Die.addValue(DIEValueAllocator, Attribute, Block->BestForm(), Block);
void DwarfUnit::addSourceLine(DIE &Die, unsigned Line, const DIFile *File) {
if (Line == 0)
unsigned FileID = getOrCreateSourceID(File);
assert(FileID && "Invalid file id");
addUInt(Die, dwarf::DW_AT_decl_file, None, FileID);
addUInt(Die, dwarf::DW_AT_decl_line, None, Line);
void DwarfUnit::addSourceLine(DIE &Die, const DILocalVariable *V) {
addSourceLine(Die, V->getLine(), V->getFile());
void DwarfUnit::addSourceLine(DIE &Die, const DIGlobalVariable *G) {
addSourceLine(Die, G->getLine(), G->getFile());
void DwarfUnit::addSourceLine(DIE &Die, const DISubprogram *SP) {
addSourceLine(Die, SP->getLine(), SP->getFile());
void DwarfUnit::addSourceLine(DIE &Die, const DILabel *L) {
addSourceLine(Die, L->getLine(), L->getFile());
void DwarfUnit::addSourceLine(DIE &Die, const DIType *Ty) {
addSourceLine(Die, Ty->getLine(), Ty->getFile());
void DwarfUnit::addSourceLine(DIE &Die, const DIObjCProperty *Ty) {
addSourceLine(Die, Ty->getLine(), Ty->getFile());
/// Return true if type encoding is unsigned.
static bool isUnsignedDIType(DwarfDebug *DD, const DIType *Ty) {
if (auto *CTy = dyn_cast<DICompositeType>(Ty)) {
// FIXME: Enums without a fixed underlying type have unknown signedness
// here, leading to incorrectly emitted constants.
if (CTy->getTag() == dwarf::DW_TAG_enumeration_type)
return false;
// (Pieces of) aggregate types that get hacked apart by SROA may be
// represented by a constant. Encode them as unsigned bytes.
return true;
if (auto *DTy = dyn_cast<DIDerivedType>(Ty)) {
dwarf::Tag T = (dwarf::Tag)Ty->getTag();
// Encode pointer constants as unsigned bytes. This is used at least for
// null pointer constant emission.
// FIXME: reference and rvalue_reference /probably/ shouldn't be allowed
// here, but accept them for now due to a bug in SROA producing bogus
// dbg.values.
if (T == dwarf::DW_TAG_pointer_type ||
T == dwarf::DW_TAG_ptr_to_member_type ||
T == dwarf::DW_TAG_reference_type ||
T == dwarf::DW_TAG_rvalue_reference_type)
return true;
assert(T == dwarf::DW_TAG_typedef || T == dwarf::DW_TAG_const_type ||
T == dwarf::DW_TAG_volatile_type ||
T == dwarf::DW_TAG_restrict_type || T == dwarf::DW_TAG_atomic_type);
DITypeRef Deriv = DTy->getBaseType();
assert(Deriv && "Expected valid base type");
return isUnsignedDIType(DD, DD->resolve(Deriv));
auto *BTy = cast<DIBasicType>(Ty);
unsigned Encoding = BTy->getEncoding();
assert((Encoding == dwarf::DW_ATE_unsigned ||
Encoding == dwarf::DW_ATE_unsigned_char ||
Encoding == dwarf::DW_ATE_signed ||
Encoding == dwarf::DW_ATE_signed_char ||
Encoding == dwarf::DW_ATE_float || Encoding == dwarf::DW_ATE_UTF ||
Encoding == dwarf::DW_ATE_boolean ||
(Ty->getTag() == dwarf::DW_TAG_unspecified_type &&
Ty->getName() == "decltype(nullptr)")) &&
"Unsupported encoding");
return Encoding == dwarf::DW_ATE_unsigned ||
Encoding == dwarf::DW_ATE_unsigned_char ||
Encoding == dwarf::DW_ATE_UTF || Encoding == dwarf::DW_ATE_boolean ||
Ty->getTag() == dwarf::DW_TAG_unspecified_type;
void DwarfUnit::addConstantFPValue(DIE &Die, const MachineOperand &MO) {
assert(MO.isFPImm() && "Invalid machine operand!");
DIEBlock *Block = new (DIEValueAllocator) DIEBlock;
APFloat FPImm = MO.getFPImm()->getValueAPF();
// Get the raw data form of the floating point.
const APInt FltVal = FPImm.bitcastToAPInt();
const char *FltPtr = (const char *)FltVal.getRawData();
int NumBytes = FltVal.getBitWidth() / 8; // 8 bits per byte.
bool LittleEndian = Asm->getDataLayout().isLittleEndian();
int Incr = (LittleEndian ? 1 : -1);
int Start = (LittleEndian ? 0 : NumBytes - 1);
int Stop = (LittleEndian ? NumBytes : -1);
// Output the constant to DWARF one byte at a time.
for (; Start != Stop; Start += Incr)
addUInt(*Block, dwarf::DW_FORM_data1, (unsigned char)0xFF & FltPtr[Start]);
addBlock(Die, dwarf::DW_AT_const_value, Block);
void DwarfUnit::addConstantFPValue(DIE &Die, const ConstantFP *CFP) {
// Pass this down to addConstantValue as an unsigned bag of bits.
addConstantValue(Die, CFP->getValueAPF().bitcastToAPInt(), true);
void DwarfUnit::addConstantValue(DIE &Die, const ConstantInt *CI,
const DIType *Ty) {
addConstantValue(Die, CI->getValue(), Ty);
void DwarfUnit::addConstantValue(DIE &Die, const MachineOperand &MO,
const DIType *Ty) {
assert(MO.isImm() && "Invalid machine operand!");
addConstantValue(Die, isUnsignedDIType(DD, Ty), MO.getImm());
void DwarfUnit::addConstantValue(DIE &Die, bool Unsigned, uint64_t Val) {
// FIXME: This is a bit conservative/simple - it emits negative values always
// sign extended to 64 bits rather than minimizing the number of bytes.
addUInt(Die, dwarf::DW_AT_const_value,
Unsigned ? dwarf::DW_FORM_udata : dwarf::DW_FORM_sdata, Val);
void DwarfUnit::addConstantValue(DIE &Die, const APInt &Val, const DIType *Ty) {
addConstantValue(Die, Val, isUnsignedDIType(DD, Ty));
void DwarfUnit::addConstantValue(DIE &Die, const APInt &Val, bool Unsigned) {
unsigned CIBitWidth = Val.getBitWidth();
if (CIBitWidth <= 64) {
addConstantValue(Die, Unsigned,
Unsigned ? Val.getZExtValue() : Val.getSExtValue());
DIEBlock *Block = new (DIEValueAllocator) DIEBlock;
// Get the raw data form of the large APInt.
const uint64_t *Ptr64 = Val.getRawData();
int NumBytes = Val.getBitWidth() / 8; // 8 bits per byte.
bool LittleEndian = Asm->getDataLayout().isLittleEndian();
// Output the constant to DWARF one byte at a time.
for (int i = 0; i < NumBytes; i++) {
uint8_t c;
if (LittleEndian)
c = Ptr64[i / 8] >> (8 * (i & 7));
c = Ptr64[(NumBytes - 1 - i) / 8] >> (8 * ((NumBytes - 1 - i) & 7));
addUInt(*Block, dwarf::DW_FORM_data1, c);
addBlock(Die, dwarf::DW_AT_const_value, Block);
void DwarfUnit::addLinkageName(DIE &Die, StringRef LinkageName) {
if (!LinkageName.empty())
DD->getDwarfVersion() >= 4 ? dwarf::DW_AT_linkage_name
: dwarf::DW_AT_MIPS_linkage_name,
void DwarfUnit::addTemplateParams(DIE &Buffer, DINodeArray TParams) {
// Add template parameters.
for (const auto *Element : TParams) {
if (auto *TTP = dyn_cast<DITemplateTypeParameter>(Element))
constructTemplateTypeParameterDIE(Buffer, TTP);
else if (auto *TVP = dyn_cast<DITemplateValueParameter>(Element))
constructTemplateValueParameterDIE(Buffer, TVP);
/// Add thrown types.
void DwarfUnit::addThrownTypes(DIE &Die, DINodeArray ThrownTypes) {
for (const auto *Ty : ThrownTypes) {
DIE &TT = createAndAddDIE(dwarf::DW_TAG_thrown_type, Die);
addType(TT, cast<DIType>(Ty));
DIE *DwarfUnit::getOrCreateContextDIE(const DIScope *Context) {
if (!Context || isa<DIFile>(Context))
return &getUnitDie();
if (auto *T = dyn_cast<DIType>(Context))
return getOrCreateTypeDIE(T);
if (auto *NS = dyn_cast<DINamespace>(Context))
return getOrCreateNameSpace(NS);
if (auto *SP = dyn_cast<DISubprogram>(Context))
return getOrCreateSubprogramDIE(SP);
if (auto *M = dyn_cast<DIModule>(Context))
return getOrCreateModule(M);
return getDIE(Context);
DIE *DwarfTypeUnit::createTypeDIE(const DICompositeType *Ty) {
auto *Context = resolve(Ty->getScope());
DIE *ContextDIE = getOrCreateContextDIE(Context);
if (DIE *TyDIE = getDIE(Ty))
return TyDIE;
// Create new type.
DIE &TyDIE = createAndAddDIE(Ty->getTag(), *ContextDIE, Ty);
constructTypeDIE(TyDIE, cast<DICompositeType>(Ty));
updateAcceleratorTables(Context, Ty, TyDIE);
return &TyDIE;
DIE *DwarfUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
if (!TyNode)
return nullptr;
auto *Ty = cast<DIType>(TyNode);
// DW_TAG_restrict_type is not supported in DWARF2
if (Ty->getTag() == dwarf::DW_TAG_restrict_type && DD->getDwarfVersion() <= 2)
return getOrCreateTypeDIE(resolve(cast<DIDerivedType>(Ty)->getBaseType()));
// DW_TAG_atomic_type is not supported in DWARF < 5
if (Ty->getTag() == dwarf::DW_TAG_atomic_type && DD->getDwarfVersion() < 5)
return getOrCreateTypeDIE(resolve(cast<DIDerivedType>(Ty)->getBaseType()));
// Construct the context before querying for the existence of the DIE in case
// such construction creates the DIE.
auto *Context = resolve(Ty->getScope());
DIE *ContextDIE = getOrCreateContextDIE(Context);
if (DIE *TyDIE = getDIE(Ty))
return TyDIE;
// Create new type.
DIE &TyDIE = createAndAddDIE(Ty->getTag(), *ContextDIE, Ty);
updateAcceleratorTables(Context, Ty, TyDIE);
if (auto *BT = dyn_cast<DIBasicType>(Ty))
constructTypeDIE(TyDIE, BT);
else if (auto *STy = dyn_cast<DISubroutineType>(Ty))
constructTypeDIE(TyDIE, STy);
else if (auto *CTy = dyn_cast<DICompositeType>(Ty)) {
if (DD->generateTypeUnits() && !Ty->isForwardDecl())
if (MDString *TypeId = CTy->getRawIdentifier()) {
DD->addDwarfTypeUnitType(getCU(), TypeId->getString(), TyDIE, CTy);
// Skip updating the accelerator tables since this is not the full type.
return &TyDIE;
constructTypeDIE(TyDIE, CTy);
} else {
constructTypeDIE(TyDIE, cast<DIDerivedType>(Ty));
return &TyDIE;
void DwarfUnit::updateAcceleratorTables(const DIScope *Context,
const DIType *Ty, const DIE &TyDIE) {
if (!Ty->getName().empty() && !Ty->isForwardDecl()) {
bool IsImplementation = false;
if (auto *CT = dyn_cast<DICompositeType>(Ty)) {
// A runtime language of 0 actually means C/C++ and that any
// non-negative value is some version of Objective-C/C++.
IsImplementation = CT->getRuntimeLang() == 0 || CT->isObjcClassComplete();
unsigned Flags = IsImplementation ? dwarf::DW_FLAG_type_implementation : 0;
DD->addAccelType(*CUNode, Ty->getName(), TyDIE, Flags);
if (!Context || isa<DICompileUnit>(Context) || isa<DIFile>(Context) ||
addGlobalType(Ty, TyDIE, Context);
void DwarfUnit::addType(DIE &Entity, const DIType *Ty,
dwarf::Attribute Attribute) {
assert(Ty && "Trying to add a type that doesn't exist?");
addDIEEntry(Entity, Attribute, DIEEntry(*getOrCreateTypeDIE(Ty)));
std::string DwarfUnit::getParentContextString(const DIScope *Context) const {
if (!Context)
return "";
// FIXME: Decide whether to implement this for non-C++ languages.
if (getLanguage() != dwarf::DW_LANG_C_plus_plus)
return "";
std::string CS;
SmallVector<const DIScope *, 1> Parents;
while (!isa<DICompileUnit>(Context)) {
if (Context->getScope())
Context = resolve(Context->getScope());
// Structure, etc types will have a NULL context if they're at the top
// level.
// Reverse iterate over our list to go from the outermost construct to the
// innermost.
for (const DIScope *Ctx : make_range(Parents.rbegin(), Parents.rend())) {
StringRef Name = Ctx->getName();
if (Name.empty() && isa<DINamespace>(Ctx))
Name = "(anonymous namespace)";
if (!Name.empty()) {
CS += Name;
CS += "::";
return CS;
void DwarfUnit::constructTypeDIE(DIE &Buffer, const DIBasicType *BTy) {
// Get core information.
StringRef Name = BTy->getName();
// Add name if not anonymous or intermediate type.
if (!Name.empty())
addString(Buffer, dwarf::DW_AT_name, Name);
// An unspecified type only has a name attribute.
if (BTy->getTag() == dwarf::DW_TAG_unspecified_type)
addUInt(Buffer, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1,
uint64_t Size = BTy->getSizeInBits() >> 3;
addUInt(Buffer, dwarf::DW_AT_byte_size, None, Size);
if (BTy->isBigEndian())
addUInt(Buffer, dwarf::DW_AT_endianity, None, dwarf::DW_END_big);
else if (BTy->isLittleEndian())
addUInt(Buffer, dwarf::DW_AT_endianity, None, dwarf::DW_END_little);
void DwarfUnit::constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy) {
// Get core information.
StringRef Name = DTy->getName();
uint64_t Size = DTy->getSizeInBits() >> 3;
uint16_t Tag = Buffer.getTag();
// Map to main type, void will not have a type.
const DIType *FromTy = resolve(DTy->getBaseType());
if (FromTy)
addType(Buffer, FromTy);
// Add name if not anonymous or intermediate type.
if (!Name.empty())
addString(Buffer, dwarf::DW_AT_name, Name);
// Add size if non-zero (derived types might be zero-sized.)
if (Size && Tag != dwarf::DW_TAG_pointer_type
&& Tag != dwarf::DW_TAG_ptr_to_member_type
&& Tag != dwarf::DW_TAG_reference_type
&& Tag != dwarf::DW_TAG_rvalue_reference_type)
addUInt(Buffer, dwarf::DW_AT_byte_size, None, Size);
if (Tag == dwarf::DW_TAG_ptr_to_member_type)
Buffer, dwarf::DW_AT_containing_type,
// Add source line info if available and TyDesc is not a forward declaration.
if (!DTy->isForwardDecl())
addSourceLine(Buffer, DTy);
// If DWARF address space value is other than None, add it for pointer and
// reference types as DW_AT_address_class.
if (DTy->getDWARFAddressSpace() && (Tag == dwarf::DW_TAG_pointer_type ||
Tag == dwarf::DW_TAG_reference_type))
addUInt(Buffer, dwarf::DW_AT_address_class, dwarf::DW_FORM_data4,
void DwarfUnit::constructSubprogramArguments(DIE &Buffer, DITypeRefArray Args) {
for (unsigned i = 1, N = Args.size(); i < N; ++i) {
const DIType *Ty = resolve(Args[i]);
if (!Ty) {
assert(i == N-1 && "Unspecified parameter must be the last argument");
createAndAddDIE(dwarf::DW_TAG_unspecified_parameters, Buffer);
} else {
DIE &Arg = createAndAddDIE(dwarf::DW_TAG_formal_parameter, Buffer);
addType(Arg, Ty);
if (Ty->isArtificial())
addFlag(Arg, dwarf::DW_AT_artificial);
void DwarfUnit::constructTypeDIE(DIE &Buffer, const DISubroutineType *CTy) {
// Add return type. A void return won't have a type.
auto Elements = cast<DISubroutineType>(CTy)->getTypeArray();
if (Elements.size())
if (auto RTy = resolve(Elements[0]))
addType(Buffer, RTy);
bool isPrototyped = true;
if (Elements.size() == 2 && !Elements[1])
isPrototyped = false;
constructSubprogramArguments(Buffer, Elements);
// Add prototype flag if we're dealing with a C language and the function has
// been prototyped.
uint16_t Language = getLanguage();
if (isPrototyped &&
(Language == dwarf::DW_LANG_C89 || Language == dwarf::DW_LANG_C99 ||
Language == dwarf::DW_LANG_ObjC))
addFlag(Buffer, dwarf::DW_AT_prototyped);
// Add a DW_AT_calling_convention if this has an explicit convention.
if (CTy->getCC() && CTy->getCC() != dwarf::DW_CC_normal)
addUInt(Buffer, dwarf::DW_AT_calling_convention, dwarf::DW_FORM_data1,
if (CTy->isLValueReference())
addFlag(Buffer, dwarf::DW_AT_reference);
if (CTy->isRValueReference())
addFlag(Buffer, dwarf::DW_AT_rvalue_reference);
void DwarfUnit::constructTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
// Add name if not anonymous or intermediate type.
StringRef Name = CTy->getName();
uint64_t Size = CTy->getSizeInBits() >> 3;
uint16_t Tag = Buffer.getTag();
switch (Tag) {
case dwarf::DW_TAG_array_type:
constructArrayTypeDIE(Buffer, CTy);
case dwarf::DW_TAG_enumeration_type:
constructEnumTypeDIE(Buffer, CTy);
case dwarf::DW_TAG_variant_part:
case dwarf::DW_TAG_structure_type:
case dwarf::DW_TAG_union_type:
case dwarf::DW_TAG_class_type: {
// Emit the discriminator for a variant part.
DIDerivedType *Discriminator = nullptr;
if (Tag == dwarf::DW_TAG_variant_part) {
Discriminator = CTy->getDiscriminator();
if (Discriminator) {
// DWARF says:
// If the variant part has a discriminant, the discriminant is
// represented by a separate debugging information entry which is
// a child of the variant part entry.
DIE &DiscMember = constructMemberDIE(Buffer, Discriminator);
addDIEEntry(Buffer, dwarf::DW_AT_discr, DiscMember);
// Add elements to structure type.
DINodeArray Elements = CTy->getElements();
for (const auto *Element : Elements) {
if (!Element)
if (auto *SP = dyn_cast<DISubprogram>(Element))
else if (auto *DDTy = dyn_cast<DIDerivedType>(Element)) {
if (DDTy->getTag() == dwarf::DW_TAG_friend) {
DIE &ElemDie = createAndAddDIE(dwarf::DW_TAG_friend, Buffer);
addType(ElemDie, resolve(DDTy->getBaseType()), dwarf::DW_AT_friend);
} else if (DDTy->isStaticMember()) {
} else if (Tag == dwarf::DW_TAG_variant_part) {
// When emitting a variant part, wrap each member in
// DW_TAG_variant.
DIE &Variant = createAndAddDIE(dwarf::DW_TAG_variant, Buffer);
if (const ConstantInt *CI =
dyn_cast_or_null<ConstantInt>(DDTy->getDiscriminantValue())) {
if (isUnsignedDIType(DD, resolve(Discriminator->getBaseType())))
addUInt(Variant, dwarf::DW_AT_discr_value, None, CI->getZExtValue());
addSInt(Variant, dwarf::DW_AT_discr_value, None, CI->getSExtValue());
constructMemberDIE(Variant, DDTy);
} else {
constructMemberDIE(Buffer, DDTy);
} else if (auto *Property = dyn_cast<DIObjCProperty>(Element)) {
DIE &ElemDie = createAndAddDIE(Property->getTag(), Buffer);
StringRef PropertyName = Property->getName();
addString(ElemDie, dwarf::DW_AT_APPLE_property_name, PropertyName);
if (Property->getType())
addType(ElemDie, resolve(Property->getType()));
addSourceLine(ElemDie, Property);
StringRef GetterName = Property->getGetterName();
if (!GetterName.empty())
addString(ElemDie, dwarf::DW_AT_APPLE_property_getter, GetterName);
StringRef SetterName = Property->getSetterName();
if (!SetterName.empty())
addString(ElemDie, dwarf::DW_AT_APPLE_property_setter, SetterName);
if (unsigned PropertyAttributes = Property->getAttributes())
addUInt(ElemDie, dwarf::DW_AT_APPLE_property_attribute, None,
} else if (auto *Composite = dyn_cast<DICompositeType>(Element)) {
if (Composite->getTag() == dwarf::DW_TAG_variant_part) {
DIE &VariantPart = createAndAddDIE(Composite->getTag(), Buffer);
constructTypeDIE(VariantPart, Composite);
if (CTy->isAppleBlockExtension())
addFlag(Buffer, dwarf::DW_AT_APPLE_block);
// This is outside the DWARF spec, but GDB expects a DW_AT_containing_type
// inside C++ composite types to point to the base class with the vtable.
// Rust uses DW_AT_containing_type to link a vtable to the type
// for which it was created.
if (auto *ContainingType = resolve(CTy->getVTableHolder()))
addDIEEntry(Buffer, dwarf::DW_AT_containing_type,
if (CTy->isObjcClassComplete())
addFlag(Buffer, dwarf::DW_AT_APPLE_objc_complete_type);
// Add template parameters to a class, structure or union types.
// FIXME: The support isn't in the metadata for this yet.
if (Tag == dwarf::DW_TAG_class_type ||
Tag == dwarf::DW_TAG_structure_type || Tag == dwarf::DW_TAG_union_type)
addTemplateParams(Buffer, CTy->getTemplateParams());
// Add the type's non-standard calling convention.
uint8_t CC = 0;
if (CTy->isTypePassByValue())
CC = dwarf::DW_CC_pass_by_value;
else if (CTy->isTypePassByReference())
CC = dwarf::DW_CC_pass_by_reference;
if (CC)
addUInt(Buffer, dwarf::DW_AT_calling_convention, dwarf::DW_FORM_data1,
// Add name if not anonymous or intermediate type.
if (!Name.empty())
addString(Buffer, dwarf::DW_AT_name, Name);
if (Tag == dwarf::DW_TAG_enumeration_type ||
Tag == dwarf::DW_TAG_class_type || Tag == dwarf::DW_TAG_structure_type ||
Tag == dwarf::DW_TAG_union_type) {
// Add size if non-zero (derived types might be zero-sized.)
// TODO: Do we care about size for enum forward declarations?
if (Size)
addUInt(Buffer, dwarf::DW_AT_byte_size, None, Size);
else if (!CTy->isForwardDecl())
// Add zero size if it is not a forward declaration.
addUInt(Buffer, dwarf::DW_AT_byte_size, None, 0);
// If we're a forward decl, say so.
if (CTy->isForwardDecl())
addFlag(Buffer, dwarf::DW_AT_declaration);
// Add source line info if available.
if (!CTy->isForwardDecl())
addSourceLine(Buffer, CTy);
// No harm in adding the runtime language to the declaration.
unsigned RLang = CTy->getRuntimeLang();
if (RLang)
addUInt(Buffer, dwarf::DW_AT_APPLE_runtime_class, dwarf::DW_FORM_data1,
// Add align info if available.
if (uint32_t AlignInBytes = CTy->getAlignInBytes())
addUInt(Buffer, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
void DwarfUnit::constructTemplateTypeParameterDIE(
DIE &Buffer, const DITemplateTypeParameter *TP) {
DIE &ParamDIE =
createAndAddDIE(dwarf::DW_TAG_template_type_parameter, Buffer);
// Add the type if it exists, it could be void and therefore no type.
if (TP->getType())
addType(ParamDIE, resolve(TP->getType()));
if (!TP->getName().empty())
addString(ParamDIE, dwarf::DW_AT_name, TP->getName());
void DwarfUnit::constructTemplateValueParameterDIE(
DIE &Buffer, const DITemplateValueParameter *VP) {
DIE &ParamDIE = createAndAddDIE(VP->getTag(), Buffer);
// Add the type if there is one, template template and template parameter
// packs will not have a type.
if (VP->getTag() == dwarf::DW_TAG_template_value_parameter)
addType(ParamDIE, resolve(VP->getType()));
if (!VP->getName().empty())
addString(ParamDIE, dwarf::DW_AT_name, VP->getName());
if (Metadata *Val = VP->getValue()) {
if (ConstantInt *CI = mdconst::dyn_extract<ConstantInt>(Val))
addConstantValue(ParamDIE, CI, resolve(VP->getType()));
else if (GlobalValue *GV = mdconst::dyn_extract<GlobalValue>(Val)) {
// We cannot describe the location of dllimport'd entities: the
// computation of their address requires loads from the IAT.
if (!GV->hasDLLImportStorageClass()) {
// For declaration non-type template parameters (such as global values
// and functions)
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
addOpAddress(*Loc, Asm->getSymbol(GV));
// Emit DW_OP_stack_value to use the address as the immediate value of
// the parameter, rather than a pointer to it.
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_stack_value);
addBlock(ParamDIE, dwarf::DW_AT_location, Loc);
} else if (VP->getTag() == dwarf::DW_TAG_GNU_template_template_param) {
addString(ParamDIE, dwarf::DW_AT_GNU_template_name,
} else if (VP->getTag() == dwarf::DW_TAG_GNU_template_parameter_pack) {
addTemplateParams(ParamDIE, cast<MDTuple>(Val));
DIE *DwarfUnit::getOrCreateNameSpace(const DINamespace *NS) {
// Construct the context before querying for the existence of the DIE in case
// such construction creates the DIE.
DIE *ContextDIE = getOrCreateContextDIE(NS->getScope());
if (DIE *NDie = getDIE(NS))
return NDie;
DIE &NDie = createAndAddDIE(dwarf::DW_TAG_namespace, *ContextDIE, NS);
StringRef Name = NS->getName();
if (!Name.empty())
addString(NDie, dwarf::DW_AT_name, NS->getName());
Name = "(anonymous namespace)";
DD->addAccelNamespace(*CUNode, Name, NDie);
addGlobalName(Name, NDie, NS->getScope());
if (NS->getExportSymbols())
addFlag(NDie, dwarf::DW_AT_export_symbols);
return &NDie;
DIE *DwarfUnit::getOrCreateModule(const DIModule *M) {
// Construct the context before querying for the existence of the DIE in case
// such construction creates the DIE.
DIE *ContextDIE = getOrCreateContextDIE(M->getScope());
if (DIE *MDie = getDIE(M))
return MDie;
DIE &MDie = createAndAddDIE(dwarf::DW_TAG_module, *ContextDIE, M);
if (!M->getName().empty()) {
addString(MDie, dwarf::DW_AT_name, M->getName());
addGlobalName(M->getName(), MDie, M->getScope());
if (!M->getConfigurationMacros().empty())
addString(MDie, dwarf::DW_AT_LLVM_config_macros,
if (!M->getIncludePath().empty())
addString(MDie, dwarf::DW_AT_LLVM_include_path, M->getIncludePath());
if (!M->getISysRoot().empty())
addString(MDie, dwarf::DW_AT_LLVM_isysroot, M->getISysRoot());
return &MDie;
DIE *DwarfUnit::getOrCreateSubprogramDIE(const DISubprogram *SP, bool Minimal) {
// Construct the context before querying for the existence of the DIE in case
// such construction creates the DIE (as is the case for member function
// declarations).
DIE *ContextDIE =
Minimal ? &getUnitDie() : getOrCreateContextDIE(resolve(SP->getScope()));
if (DIE *SPDie = getDIE(SP))
return SPDie;
if (auto *SPDecl = SP->getDeclaration()) {
if (!Minimal) {
// Add subprogram definitions to the CU die directly.
ContextDIE = &getUnitDie();
// Build the decl now to ensure it precedes the definition.
// DW_TAG_inlined_subroutine may refer to this DIE.
DIE &SPDie = createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, SP);
// Stop here and fill this in later, depending on whether or not this
// subprogram turns out to have inlined instances or not.
if (SP->isDefinition())
return &SPDie;
applySubprogramAttributes(SP, SPDie);
return &SPDie;
bool DwarfUnit::applySubprogramDefinitionAttributes(const DISubprogram *SP,
DIE &SPDie) {
DIE *DeclDie = nullptr;
StringRef DeclLinkageName;
if (auto *SPDecl = SP->getDeclaration()) {
DeclDie = getDIE(SPDecl);
assert(DeclDie && "This DIE should've already been constructed when the "
"definition DIE was created in "
// Look at the Decl's linkage name only if we emitted it.
if (DD->useAllLinkageNames())
DeclLinkageName = SPDecl->getLinkageName();
unsigned DeclID = getOrCreateSourceID(SPDecl->getFile());
unsigned DefID = getOrCreateSourceID(SP->getFile());
if (DeclID != DefID)
addUInt(SPDie, dwarf::DW_AT_decl_file, None, DefID);
if (SP->getLine() != SPDecl->getLine())
addUInt(SPDie, dwarf::DW_AT_decl_line, None, SP->getLine());
// Add function template parameters.
addTemplateParams(SPDie, SP->getTemplateParams());
// Add the linkage name if we have one and it isn't in the Decl.
StringRef LinkageName = SP->getLinkageName();
assert(((LinkageName.empty() || DeclLinkageName.empty()) ||
LinkageName == DeclLinkageName) &&
"decl has a linkage name and it is different");
if (DeclLinkageName.empty() &&
// Always emit it for abstract subprograms.
(DD->useAllLinkageNames() || DU->getAbstractSPDies().lookup(SP)))
addLinkageName(SPDie, LinkageName);
if (!DeclDie)
return false;
// Refer to the function declaration where all the other attributes will be
// found.
addDIEEntry(SPDie, dwarf::DW_AT_specification, *DeclDie);
return true;
void DwarfUnit::applySubprogramAttributes(const DISubprogram *SP, DIE &SPDie,
bool SkipSPAttributes) {
// If -fdebug-info-for-profiling is enabled, need to emit the subprogram
// and its source location.
bool SkipSPSourceLocation = SkipSPAttributes &&
if (!SkipSPSourceLocation)
if (applySubprogramDefinitionAttributes(SP, SPDie))
// Constructors and operators for anonymous aggregates do not have names.
if (!SP->getName().empty())
addString(SPDie, dwarf::DW_AT_name, SP->getName());
if (!SkipSPSourceLocation)
addSourceLine(SPDie, SP);
// Skip the rest of the attributes under -gmlt to save space.
if (SkipSPAttributes)
// Add the prototype if we have a prototype and we have a C like
// language.
uint16_t Language = getLanguage();
if (SP->isPrototyped() &&
(Language == dwarf::DW_LANG_C89 || Language == dwarf::DW_LANG_C99 ||
Language == dwarf::DW_LANG_ObjC))
addFlag(SPDie, dwarf::DW_AT_prototyped);
unsigned CC = 0;
DITypeRefArray Args;
if (const DISubroutineType *SPTy = SP->getType()) {
Args = SPTy->getTypeArray();
CC = SPTy->getCC();
// Add a DW_AT_calling_convention if this has an explicit convention.
if (CC && CC != dwarf::DW_CC_normal)
addUInt(SPDie, dwarf::DW_AT_calling_convention, dwarf::DW_FORM_data1, CC);
// Add a return type. If this is a type like a C/C++ void type we don't add a
// return type.
if (Args.size())
if (auto Ty = resolve(Args[0]))
addType(SPDie, Ty);
unsigned VK = SP->getVirtuality();
if (VK) {
addUInt(SPDie, dwarf::DW_AT_virtuality, dwarf::DW_FORM_data1, VK);
if (SP->getVirtualIndex() != -1u) {
DIELoc *Block = getDIELoc();
addUInt(*Block, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
addUInt(*Block, dwarf::DW_FORM_udata, SP->getVirtualIndex());
addBlock(SPDie, dwarf::DW_AT_vtable_elem_location, Block);
std::make_pair(&SPDie, resolve(SP->getContainingType())));
if (!SP->isDefinition()) {
addFlag(SPDie, dwarf::DW_AT_declaration);
// Add arguments. Do not add arguments for subprogram definition. They will
// be handled while processing variables.
constructSubprogramArguments(SPDie, Args);
addThrownTypes(SPDie, SP->getThrownTypes());
if (SP->isArtificial())
addFlag(SPDie, dwarf::DW_AT_artificial);
if (!SP->isLocalToUnit())
addFlag(SPDie, dwarf::DW_AT_external);
if (DD->useAppleExtensionAttributes()) {
if (SP->isOptimized())
addFlag(SPDie, dwarf::DW_AT_APPLE_optimized);
if (unsigned isa = Asm->getISAEncoding())
addUInt(SPDie, dwarf::DW_AT_APPLE_isa, dwarf::DW_FORM_flag, isa);
if (SP->isLValueReference())
addFlag(SPDie, dwarf::DW_AT_reference);
if (SP->isRValueReference())
addFlag(SPDie, dwarf::DW_AT_rvalue_reference);
if (SP->isNoReturn())
addFlag(SPDie, dwarf::DW_AT_noreturn);
if (SP->isProtected())
addUInt(SPDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
else if (SP->isPrivate())
addUInt(SPDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
else if (SP->isPublic())
addUInt(SPDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
if (SP->isExplicit())
addFlag(SPDie, dwarf::DW_AT_explicit);
if (SP->isMainSubprogram())
addFlag(SPDie, dwarf::DW_AT_main_subprogram);
void DwarfUnit::constructSubrangeDIE(DIE &Buffer, const DISubrange *SR,
DIE *IndexTy) {
DIE &DW_Subrange = createAndAddDIE(dwarf::DW_TAG_subrange_type, Buffer);
addDIEEntry(DW_Subrange, dwarf::DW_AT_type, *IndexTy);
// The LowerBound value defines the lower bounds which is typically zero for
// C/C++. The Count value is the number of elements. Values are 64 bit. If
// Count == -1 then the array is unbounded and we do not emit
// DW_AT_lower_bound and DW_AT_count attributes.
int64_t LowerBound = SR->getLowerBound();
int64_t DefaultLowerBound = getDefaultLowerBound();
int64_t Count = -1;
if (auto *CI = SR->getCount().dyn_cast<ConstantInt*>())
Count = CI->getSExtValue();
if (DefaultLowerBound == -1 || LowerBound != DefaultLowerBound)
addUInt(DW_Subrange, dwarf::DW_AT_lower_bound, None, LowerBound);
if (auto *CV = SR->getCount().dyn_cast<DIVariable*>()) {
if (auto *CountVarDIE = getDIE(CV))
addDIEEntry(DW_Subrange, dwarf::DW_AT_count, *CountVarDIE);
} else if (Count != -1)
addUInt(DW_Subrange, dwarf::DW_AT_count, None, Count);
DIE *DwarfUnit::getIndexTyDie() {
if (IndexTyDie)
return IndexTyDie;
// Construct an integer type to use for indexes.
IndexTyDie = &createAndAddDIE(dwarf::DW_TAG_base_type, getUnitDie());
StringRef Name = "__ARRAY_SIZE_TYPE__";
addString(*IndexTyDie, dwarf::DW_AT_name, Name);
addUInt(*IndexTyDie, dwarf::DW_AT_byte_size, None, sizeof(int64_t));
addUInt(*IndexTyDie, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1,
DD->addAccelType(*CUNode, Name, *IndexTyDie, /*Flags*/ 0);
return IndexTyDie;
/// Returns true if the vector's size differs from the sum of sizes of elements
/// the user specified. This can occur if the vector has been rounded up to
/// fit memory alignment constraints.
static bool hasVectorBeenPadded(const DICompositeType *CTy) {
assert(CTy && CTy->isVector() && "Composite type is not a vector");
const uint64_t ActualSize = CTy->getSizeInBits();
// Obtain the size of each element in the vector.
DIType *BaseTy = CTy->getBaseType().resolve();
assert(BaseTy && "Unknown vector element type.");
const uint64_t ElementSize = BaseTy->getSizeInBits();
// Locate the number of elements in the vector.
const DINodeArray Elements = CTy->getElements();
assert(Elements.size() == 1 &&
Elements[0]->getTag() == dwarf::DW_TAG_subrange_type &&
"Invalid vector element array, expected one element of type subrange");
const auto Subrange = cast<DISubrange>(Elements[0]);
const auto CI = Subrange->getCount().get<ConstantInt *>();
const int32_t NumVecElements = CI->getSExtValue();
// Ensure we found the element count and that the actual size is wide
// enough to contain the requested size.
assert(ActualSize >= (NumVecElements * ElementSize) && "Invalid vector size");
return ActualSize != (NumVecElements * ElementSize);
void DwarfUnit::constructArrayTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
if (CTy->isVector()) {
addFlag(Buffer, dwarf::DW_AT_GNU_vector);
if (hasVectorBeenPadded(CTy))
addUInt(Buffer, dwarf::DW_AT_byte_size, None,
CTy->getSizeInBits() / CHAR_BIT);
// Emit the element type.
addType(Buffer, resolve(CTy->getBaseType()));
// Get an anonymous type for index type.
// FIXME: This type should be passed down from the front end
// as different languages may have different sizes for indexes.
DIE *IdxTy = getIndexTyDie();
// Add subranges to array type.
DINodeArray Elements = CTy->getElements();
for (unsigned i = 0, N = Elements.size(); i < N; ++i) {
// FIXME: Should this really be such a loose cast?
if (auto *Element = dyn_cast_or_null<DINode>(Elements[i]))
if (Element->getTag() == dwarf::DW_TAG_subrange_type)
constructSubrangeDIE(Buffer, cast<DISubrange>(Element), IdxTy);
void DwarfUnit::constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
const DIType *DTy = resolve(CTy->getBaseType());
bool IsUnsigned = DTy && isUnsignedDIType(DD, DTy);
if (DTy) {
if (DD->getDwarfVersion() >= 3)
addType(Buffer, DTy);
if (DD->getDwarfVersion() >= 4 && (CTy->getFlags() & DINode::FlagEnumClass))
addFlag(Buffer, dwarf::DW_AT_enum_class);
DINodeArray Elements = CTy->getElements();
// Add enumerators to enumeration type.
for (unsigned i = 0, N = Elements.size(); i < N; ++i) {
auto *Enum = dyn_cast_or_null<DIEnumerator>(Elements[i]);
if (Enum) {
DIE &Enumerator = createAndAddDIE(dwarf::DW_TAG_enumerator, Buffer);
StringRef Name = Enum->getName();
addString(Enumerator, dwarf::DW_AT_name, Name);
auto Value = static_cast<uint64_t>(Enum->getValue());
addConstantValue(Enumerator, IsUnsigned, Value);
void DwarfUnit::constructContainingTypeDIEs() {
for (auto CI = ContainingTypeMap.begin(), CE = ContainingTypeMap.end();
CI != CE; ++CI) {
DIE &SPDie = *CI->first;
const DINode *D = CI->second;
if (!D)
DIE *NDie = getDIE(D);
if (!NDie)
addDIEEntry(SPDie, dwarf::DW_AT_containing_type, *NDie);
DIE &DwarfUnit::constructMemberDIE(DIE &Buffer, const DIDerivedType *DT) {
DIE &MemberDie = createAndAddDIE(DT->getTag(), Buffer);
StringRef Name = DT->getName();
if (!Name.empty())
addString(MemberDie, dwarf::DW_AT_name, Name);
if (DIType *Resolved = resolve(DT->getBaseType()))
addType(MemberDie, Resolved);
addSourceLine(MemberDie, DT);
if (DT->getTag() == dwarf::DW_TAG_inheritance && DT->isVirtual()) {
// For C++, virtual base classes are not at fixed offset. Use following
// expression to extract appropriate offset from vtable.
// BaseAddr = ObAddr + *((*ObAddr) - Offset)
DIELoc *VBaseLocationDie = new (DIEValueAllocator) DIELoc;
addUInt(*VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_dup);
addUInt(*VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
addUInt(*VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
addUInt(*VBaseLocationDie, dwarf::DW_FORM_udata, DT->getOffsetInBits());
addUInt(*VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_minus);
addUInt(*VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_deref);
addUInt(*VBaseLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
addBlock(MemberDie, dwarf::DW_AT_data_member_location, VBaseLocationDie);
} else {
uint64_t Size = DT->getSizeInBits();
uint64_t FieldSize = DD->getBaseTypeSize(DT);
uint32_t AlignInBytes = DT->getAlignInBytes();
uint64_t OffsetInBytes;
bool IsBitfield = FieldSize && Size != FieldSize;
if (IsBitfield) {
// Handle bitfield, assume bytes are 8 bits.
if (DD->useDWARF2Bitfields())
addUInt(MemberDie, dwarf::DW_AT_byte_size, None, FieldSize/8);
addUInt(MemberDie, dwarf::DW_AT_bit_size, None, Size);
uint64_t Offset = DT->getOffsetInBits();
// We can't use DT->getAlignInBits() here: AlignInBits for member type
// is non-zero if and only if alignment was forced (e.g. _Alignas()),
// which can't be done with bitfields. Thus we use FieldSize here.
uint32_t AlignInBits = FieldSize;
uint32_t AlignMask = ~(AlignInBits - 1);
// The bits from the start of the storage unit to the start of the field.
uint64_t StartBitOffset = Offset - (Offset & AlignMask);
// The byte offset of the field's aligned storage unit inside the struct.
OffsetInBytes = (Offset - StartBitOffset) / 8;
if (DD->useDWARF2Bitfields()) {
uint64_t HiMark = (Offset + FieldSize) & AlignMask;
uint64_t FieldOffset = (HiMark - FieldSize);
Offset -= FieldOffset;
// Maybe we need to work from the other end.
if (Asm->getDataLayout().isLittleEndian())
Offset = FieldSize - (Offset + Size);
addUInt(MemberDie, dwarf::DW_AT_bit_offset, None, Offset);
OffsetInBytes = FieldOffset >> 3;
} else {
addUInt(MemberDie, dwarf::DW_AT_data_bit_offset, None, Offset);
} else {
// This is not a bitfield.
OffsetInBytes = DT->getOffsetInBits() / 8;
if (AlignInBytes)
addUInt(MemberDie, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
if (DD->getDwarfVersion() <= 2) {
DIELoc *MemLocationDie = new (DIEValueAllocator) DIELoc;
addUInt(*MemLocationDie, dwarf::DW_FORM_data1, dwarf::DW_OP_plus_uconst);
addUInt(*MemLocationDie, dwarf::DW_FORM_udata, OffsetInBytes);
addBlock(MemberDie, dwarf::DW_AT_data_member_location, MemLocationDie);
} else if (!IsBitfield || DD->useDWARF2Bitfields())
addUInt(MemberDie, dwarf::DW_AT_data_member_location, None,
if (DT->isProtected())
addUInt(MemberDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
else if (DT->isPrivate())
addUInt(MemberDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
// Otherwise C++ member and base classes are considered public.
else if (DT->isPublic())
addUInt(MemberDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
if (DT->isVirtual())
addUInt(MemberDie, dwarf::DW_AT_virtuality, dwarf::DW_FORM_data1,
// Objective-C properties.
if (DINode *PNode = DT->getObjCProperty())
if (DIE *PDie = getDIE(PNode))
MemberDie.addValue(DIEValueAllocator, dwarf::DW_AT_APPLE_property,
dwarf::DW_FORM_ref4, DIEEntry(*PDie));
if (DT->isArtificial())
addFlag(MemberDie, dwarf::DW_AT_artificial);
return MemberDie;
DIE *DwarfUnit::getOrCreateStaticMemberDIE(const DIDerivedType *DT) {
if (!DT)
return nullptr;
// Construct the context before querying for the existence of the DIE in case
// such construction creates the DIE.
DIE *ContextDIE = getOrCreateContextDIE(resolve(DT->getScope()));
assert(dwarf::isType(ContextDIE->getTag()) &&
"Static member should belong to a type.");
if (DIE *StaticMemberDIE = getDIE(DT))
return StaticMemberDIE;
DIE &StaticMemberDIE = createAndAddDIE(DT->getTag(), *ContextDIE, DT);
const DIType *Ty = resolve(DT->getBaseType());
addString(StaticMemberDIE, dwarf::DW_AT_name, DT->getName());
addType(StaticMemberDIE, Ty);
addSourceLine(StaticMemberDIE, DT);
addFlag(StaticMemberDIE, dwarf::DW_AT_external);
addFlag(StaticMemberDIE, dwarf::DW_AT_declaration);
// FIXME: We could omit private if the parent is a class_type, and
// public if the parent is something else.
if (DT->isProtected())
addUInt(StaticMemberDIE, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
else if (DT->isPrivate())
addUInt(StaticMemberDIE, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
else if (DT->isPublic())
addUInt(StaticMemberDIE, dwarf::DW_AT_accessibility, dwarf::DW_FORM_data1,
if (const ConstantInt *CI = dyn_cast_or_null<ConstantInt>(DT->getConstant()))
addConstantValue(StaticMemberDIE, CI, Ty);
if (const ConstantFP *CFP = dyn_cast_or_null<ConstantFP>(DT->getConstant()))
addConstantFPValue(StaticMemberDIE, CFP);
if (uint32_t AlignInBytes = DT->getAlignInBytes())
addUInt(StaticMemberDIE, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
return &StaticMemberDIE;
void DwarfUnit::emitCommonHeader(bool UseOffsets, dwarf::UnitType UT) {
// Emit size of content not including length itself
Asm->OutStreamer->AddComment("Length of Unit");
if (!DD->useSectionsAsReferences()) {
StringRef Prefix = isDwoUnit() ? "debug_info_dwo_" : "debug_info_";
MCSymbol *BeginLabel = Asm->createTempSymbol(Prefix + "start");
EndLabel = Asm->createTempSymbol(Prefix + "end");
Asm->EmitLabelDifference(EndLabel, BeginLabel, 4);
} else
Asm->emitInt32(getHeaderSize() + getUnitDie().getSize());
Asm->OutStreamer->AddComment("DWARF version number");
unsigned Version = DD->getDwarfVersion();
// DWARF v5 reorders the address size and adds a unit type.
if (Version >= 5) {
Asm->OutStreamer->AddComment("DWARF Unit Type");
Asm->OutStreamer->AddComment("Address Size (in bytes)");
// We share one abbreviations table across all units so it's always at the
// start of the section. Use a relocatable offset where needed to ensure
// linking doesn't invalidate that offset.
Asm->OutStreamer->AddComment("Offset Into Abbrev. Section");
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
if (UseOffsets)
TLOF.getDwarfAbbrevSection()->getBeginSymbol(), false);
if (Version <= 4) {
Asm->OutStreamer->AddComment("Address Size (in bytes)");
void DwarfTypeUnit::emitHeader(bool UseOffsets) {
DD->useSplitDwarf() ? dwarf::DW_UT_split_type
: dwarf::DW_UT_type);
Asm->OutStreamer->AddComment("Type Signature");
Asm->OutStreamer->EmitIntValue(TypeSignature, sizeof(TypeSignature));
Asm->OutStreamer->AddComment("Type DIE Offset");
// In a skeleton type unit there is no type DIE so emit a zero offset.
Asm->OutStreamer->EmitIntValue(Ty ? Ty->getOffset() : 0,
DwarfUnit::addSectionDelta(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Hi, const MCSymbol *Lo) {
return Die.addValue(DIEValueAllocator, Attribute,
DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
: dwarf::DW_FORM_data4,
new (DIEValueAllocator) DIEDelta(Hi, Lo));
DwarfUnit::addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label, const MCSymbol *Sec) {
if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
return addLabel(Die, Attribute,
DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
: dwarf::DW_FORM_data4,
return addSectionDelta(Die, Attribute, Label, Sec);
bool DwarfTypeUnit::isDwoUnit() const {
// Since there are no skeleton type units, all type units are dwo type units
// when split DWARF is being used.
return DD->useSplitDwarf();
void DwarfTypeUnit::addGlobalName(StringRef Name, const DIE &Die,
const DIScope *Context) {
getCU().addGlobalNameForTypeUnit(Name, Context);
void DwarfTypeUnit::addGlobalType(const DIType *Ty, const DIE &Die,
const DIScope *Context) {
getCU().addGlobalTypeUnitType(Ty, Context);
const MCSymbol *DwarfUnit::getCrossSectionRelativeBaseAddress() const {
if (!Asm->MAI->doesDwarfUseRelocationsAcrossSections())
return nullptr;
if (isDwoUnit())
return nullptr;
return getSection()->getBeginSymbol();
void DwarfUnit::addStringOffsetsStart() {
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
addSectionLabel(getUnitDie(), dwarf::DW_AT_str_offsets_base,
void DwarfUnit::addRnglistsBase() {
assert(DD->getDwarfVersion() >= 5 &&
"DW_AT_rnglists_base requires DWARF version 5 or later");
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
addSectionLabel(getUnitDie(), dwarf::DW_AT_rnglists_base,
void DwarfUnit::addLoclistsBase() {
assert(DD->getDwarfVersion() >= 5 &&
"DW_AT_loclists_base requires DWARF version 5 or later");
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
addSectionLabel(getUnitDie(), dwarf::DW_AT_loclists_base,