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//===-- llvm/CodeGen/DwarfUnit.cpp - Dwarf Type and Compile Units ---------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file contains support for constructing a dwarf compile unit.
#include "DwarfUnit.h"
#include "AddressPool.h"
#include "DwarfCompileUnit.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,
DwarfCompileUnit &CU, DIELoc &DIE)
: DwarfExpression(AP.getDwarfVersion(), CU), AP(AP), OutDIE(DIE) {}
void DIEDwarfExpression::emitOp(uint8_t Op, const char* Comment) {
CU.addUInt(getActiveDIE(), dwarf::DW_FORM_data1, Op);
void DIEDwarfExpression::emitSigned(int64_t Value) {
CU.addSInt(getActiveDIE(), dwarf::DW_FORM_sdata, Value);
void DIEDwarfExpression::emitUnsigned(uint64_t Value) {
CU.addUInt(getActiveDIE(), dwarf::DW_FORM_udata, Value);
void DIEDwarfExpression::emitData1(uint8_t Value) {
CU.addUInt(getActiveDIE(), dwarf::DW_FORM_data1, Value);
void DIEDwarfExpression::emitBaseTypeRef(uint64_t Idx) {
CU.addBaseTypeRef(getActiveDIE(), Idx);
void DIEDwarfExpression::enableTemporaryBuffer() {
assert(!IsBuffering && "Already buffering?");
IsBuffering = true;
void DIEDwarfExpression::disableTemporaryBuffer() { IsBuffering = false; }
unsigned DIEDwarfExpression::getTemporaryBufferSize() {
return TmpDIE.ComputeSize(&AP);
void DIEDwarfExpression::commitTemporaryBuffer() { OutDIE.takeValues(TmpDIE); }
bool DIEDwarfExpression::isFrameRegister(const TargetRegisterInfo &TRI,
llvm::Register MachineReg) {
return MachineReg == TRI.getFrameRegister(*AP.MF);
DwarfUnit::DwarfUnit(dwarf::Tag UnitTag, const DICompileUnit *Node,
AsmPrinter *A, DwarfDebug *DW, DwarfFile *DWU)
: DIEUnit(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 (DIEBlock *B : DIEBlocks)
for (DIELoc *L : DIELocs)
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::insertDIE(DIE *D) {
MDNodeToDieMap.insert(std::make_pair(nullptr, D));
void DwarfUnit::addFlag(DIE &Die, dwarf::Attribute Attribute) {
if (DD->getDwarfVersion() >= 4)
addAttribute(Die, Attribute, dwarf::DW_FORM_flag_present, DIEInteger(1));
addAttribute(Die, Attribute, dwarf::DW_FORM_flag, DIEInteger(1));
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");
addAttribute(Die, 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);
addAttribute(Die, 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()) {
addAttribute(Die, 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;
addAttribute(Die, Attribute, IxForm, DIEString(StringPoolEntry));
void DwarfUnit::addLabel(DIEValueList &Die, dwarf::Attribute Attribute,
dwarf::Form Form, const MCSymbol *Label) {
addAttribute(Die, 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) {
addUInt(Die, Attribute, DD->getDwarfSectionOffsetForm(), Integer);
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(), DD->getMD5AsBytes(File),
Asm->OutContext.getDwarfVersion(), File->getSource());
void DwarfUnit::addPoolOpAddress(DIEValueList &Die, const MCSymbol *Label) {
bool UseAddrOffsetFormOrExpressions =
DD->useAddrOffsetForm() || DD->useAddrOffsetExpressions();
const MCSymbol *Base = nullptr;
if (Label->isInSection() && UseAddrOffsetFormOrExpressions)
Base = DD->getSectionLabel(&Label->getSection());
uint32_t Index = DD->getAddressPool().getIndex(Base ? Base : Label);
if (DD->getDwarfVersion() >= 5) {
addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_addrx);
addUInt(Die, dwarf::DW_FORM_addrx, Index);
} else {
addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_addr_index);
addUInt(Die, dwarf::DW_FORM_GNU_addr_index, Index);
if (Base && Base != Label) {
addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_const4u);
addLabelDelta(Die, (dwarf::Attribute)0, Label, Base);
addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
void DwarfUnit::addOpAddress(DIELoc &Die, const MCSymbol *Sym) {
if (DD->getDwarfVersion() >= 5) {
addPoolOpAddress(Die, Sym);
if (DD->useSplitDwarf()) {
addPoolOpAddress(Die, Sym);
addUInt(Die, dwarf::DW_FORM_data1, dwarf::DW_OP_addr);
addLabel(Die, dwarf::DW_FORM_addr, Sym);
void DwarfUnit::addLabelDelta(DIEValueList &Die, dwarf::Attribute Attribute,
const MCSymbol *Hi, const MCSymbol *Lo) {
addAttribute(Die, 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);
addAttribute(Die, dwarf::DW_AT_signature, dwarf::DW_FORM_ref_sig8,
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();
addAttribute(Die, Attribute,
EntryCU == CU ? dwarf::DW_FORM_ref4 : dwarf::DW_FORM_ref_addr,
DIE &DwarfUnit::createAndAddDIE(dwarf::Tag Tag, DIE &Parent, const DINode *N) {
DIE &Die = Parent.addChild(DIE::get(DIEValueAllocator, 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.
addAttribute(Die, Attribute, Loc->BestForm(DD->getDwarfVersion()), Loc);
void DwarfUnit::addBlock(DIE &Die, dwarf::Attribute Attribute, dwarf::Form Form,
DIEBlock *Block) {
DIEBlocks.push_back(Block); // Memoize so we can call the destructor later on.
addAttribute(Die, Attribute, Form, Block);
void DwarfUnit::addBlock(DIE &Die, dwarf::Attribute Attribute,
DIEBlock *Block) {
addBlock(Die, Attribute, Block->BestForm(), Block);
void DwarfUnit::addSourceLine(DIE &Die, unsigned Line, const DIFile *File) {
if (Line == 0)
unsigned FileID = getOrCreateSourceID(File);
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());
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, uint64_t Val, const DIType *Ty) {
addConstantValue(Die, DD->isUnsignedDIType(Ty), Val);
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, DD->isUnsignedDIType(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 *DwarfUnit::createTypeDIE(const DICompositeType *Ty) {
auto *Context = 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::createTypeDIE(const DIScope *Context, DIE &ContextDIE,
const DIType *Ty) {
// 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 *ST = dyn_cast<DIStringType>(Ty))
constructTypeDIE(TyDIE, ST);
else if (auto *STy = dyn_cast<DISubroutineType>(Ty))
constructTypeDIE(TyDIE, STy);
else if (auto *CTy = dyn_cast<DICompositeType>(Ty)) {
if (DD->generateTypeUnits() && !Ty->isForwardDecl() &&
(Ty->getRawName() || CTy->getRawIdentifier())) {
// Skip updating the accelerator tables since this is not the full type.
if (MDString *TypeId = CTy->getRawIdentifier())
DD->addDwarfTypeUnitType(getCU(), TypeId->getString(), TyDIE, CTy);
else {
auto X = DD->enterNonTypeUnitContext();
finishNonUnitTypeDIE(TyDIE, CTy);
return &TyDIE;
constructTypeDIE(TyDIE, CTy);
} else {
constructTypeDIE(TyDIE, cast<DIDerivedType>(Ty));
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(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(cast<DIDerivedType>(Ty)->getBaseType());
// Construct the context before querying for the existence of the DIE in case
// such construction creates the DIE.
auto *Context = Ty->getScope();
DIE *ContextDIE = getOrCreateContextDIE(Context);
if (DIE *TyDIE = getDIE(Ty))
return TyDIE;
return static_cast<DwarfUnit *>(ContextDIE->getUnit())
->createTypeDIE(Context, *ContextDIE, Ty);
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) ||
isa<DINamespace>(Context) || isa<DICommonBlock>(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 (!dwarf::isCPlusPlus((dwarf::SourceLanguage)getLanguage()))
return "";
std::string CS;
SmallVector<const DIScope *, 1> Parents;
while (!isa<DICompileUnit>(Context)) {
if (const DIScope *S = Context->getScope())
Context = S;
// 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 : llvm::reverse(Parents)) {
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)
if (BTy->getTag() != dwarf::DW_TAG_string_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 DIStringType *STy) {
// Get core information.
StringRef Name = STy->getName();
// Add name if not anonymous or intermediate type.
if (!Name.empty())
addString(Buffer, dwarf::DW_AT_name, Name);
if (DIVariable *Var = STy->getStringLength()) {
if (auto *VarDIE = getDIE(Var))
addDIEEntry(Buffer, dwarf::DW_AT_string_length, *VarDIE);
} else if (DIExpression *Expr = STy->getStringLengthExp()) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, getCU(), *Loc);
// This is to describe the memory location of the
// length of a Fortran deferred length string, so
// lock it down as such.
addBlock(Buffer, dwarf::DW_AT_string_length, DwarfExpr.finalize());
} else {
uint64_t Size = STy->getSizeInBits() >> 3;
addUInt(Buffer, dwarf::DW_AT_byte_size, None, Size);
if (STy->getEncoding()) {
// For eventual Unicode support.
addUInt(Buffer, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1,
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 = 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);
addAnnotation(Buffer, DTy->getAnnotations());
// If alignment is specified for a typedef , create and insert DW_AT_alignment
// attribute in DW_TAG_typedef DIE.
if (Tag == dwarf::DW_TAG_typedef && DD->getDwarfVersion() >= 5) {
uint32_t AlignInBytes = DTy->getAlignInBytes();
if (AlignInBytes > 0)
addUInt(Buffer, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
// 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)
addDIEEntry(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. The IR
// verifier checks that DWARF address space only exists for pointer
// or reference types.
if (DTy->getDWARFAddressSpace())
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 = 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 = 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::addAnnotation(DIE &Buffer, DINodeArray Annotations) {
if (!Annotations)
for (const Metadata *Annotation : Annotations->operands()) {
const MDNode *MD = cast<MDNode>(Annotation);
const MDString *Name = cast<MDString>(MD->getOperand(0));
// Currently, only MDString is supported with btf_decl_tag attribute.
const MDString *Value = cast<MDString>(MD->getOperand(1));
DIE &AnnotationDie = createAndAddDIE(dwarf::DW_TAG_LLVM_annotation, Buffer);
addString(AnnotationDie, dwarf::DW_AT_name, Name->getString());
addString(AnnotationDie, dwarf::DW_AT_const_value, Value->getString());
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:
case dwarf::DW_TAG_namelist: {
// 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 template parameters to a class, structure or union types.
if (Tag == dwarf::DW_TAG_class_type ||
Tag == dwarf::DW_TAG_structure_type || Tag == dwarf::DW_TAG_union_type)
addTemplateParams(Buffer, CTy->getTemplateParams());
// 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, 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 (DD->isUnsignedDIType(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, 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);
} else if (Tag == dwarf::DW_TAG_namelist) {
auto *Var = dyn_cast<DINode>(Element);
auto *VarDIE = getDIE(Var);
if (VarDIE) {
DIE &ItemDie = createAndAddDIE(dwarf::DW_TAG_namelist_item, Buffer);
addDIEEntry(ItemDie, dwarf::DW_AT_namelist_item, *VarDIE);
if (CTy->isAppleBlockExtension())
addFlag(Buffer, dwarf::DW_AT_APPLE_block);
if (CTy->getExportSymbols())
addFlag(Buffer, dwarf::DW_AT_export_symbols);
// 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 = CTy->getVTableHolder())
addDIEEntry(Buffer, dwarf::DW_AT_containing_type,
if (CTy->isObjcClassComplete())
addFlag(Buffer, dwarf::DW_AT_APPLE_objc_complete_type);
// Add the type's non-standard calling convention.
// DW_CC_pass_by_value/DW_CC_pass_by_reference are introduced in DWARF 5.
if (!Asm->TM.Options.DebugStrictDwarf || DD->getDwarfVersion() >= 5) {
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);
addAnnotation(Buffer, CTy->getAnnotations());
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.)
// Ignore the size if it's a non-enum forward decl.
// TODO: Do we care about size for enum forward declarations?
if (Size &&
(!CTy->isForwardDecl() || Tag == dwarf::DW_TAG_enumeration_type))
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, TP->getType());
if (!TP->getName().empty())
addString(ParamDIE, dwarf::DW_AT_name, TP->getName());
if (TP->isDefault() && (DD->getDwarfVersion() >= 5))
addFlag(ParamDIE, dwarf::DW_AT_default_value);
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, VP->getType());
if (!VP->getName().empty())
addString(ParamDIE, dwarf::DW_AT_name, VP->getName());
if (VP->isDefault() && (DD->getDwarfVersion() >= 5))
addFlag(ParamDIE, dwarf::DW_AT_default_value);
if (Metadata *Val = VP->getValue()) {
if (ConstantInt *CI = mdconst::dyn_extract<ConstantInt>(Val))
addConstantValue(ParamDIE, CI, 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->getAPINotesFile().empty())
addString(MDie, dwarf::DW_AT_LLVM_apinotes, M->getAPINotesFile());
if (M->getFile())
addUInt(MDie, dwarf::DW_AT_decl_file, None,
if (M->getLineNo())
addUInt(MDie, dwarf::DW_AT_decl_line, None, M->getLineNo());
if (M->getIsDecl())
addFlag(MDie, dwarf::DW_AT_declaration);
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(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;
static_cast<DwarfUnit *>(SPDie.getUnit())
->applySubprogramAttributes(SP, SPDie);
return &SPDie;
bool DwarfUnit::applySubprogramDefinitionAttributes(const DISubprogram *SP,
DIE &SPDie, bool Minimal) {
DIE *DeclDie = nullptr;
StringRef DeclLinkageName;
if (auto *SPDecl = SP->getDeclaration()) {
if (!Minimal) {
DITypeRefArray DeclArgs, DefinitionArgs;
DeclArgs = SPDecl->getType()->getTypeArray();
DefinitionArgs = SP->getType()->getTypeArray();
if (DeclArgs.size() && DefinitionArgs.size())
if (DefinitionArgs[0] != NULL && DeclArgs[0] != DefinitionArgs[0])
addType(SPDie, DefinitionArgs[0]);
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, SkipSPAttributes))
// Constructors and operators for anonymous aggregates do not have names.
if (!SP->getName().empty())
addString(SPDie, dwarf::DW_AT_name, SP->getName());
addAnnotation(SPDie, SP->getAnnotations());
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);
if (SP->isObjCDirect())
addFlag(SPDie, dwarf::DW_AT_APPLE_objc_direct);
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 = 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);
ContainingTypeMap.insert(std::make_pair(&SPDie, 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);
if (SP->isPure())
addFlag(SPDie, dwarf::DW_AT_pure);
if (SP->isElemental())
addFlag(SPDie, dwarf::DW_AT_elemental);
if (SP->isRecursive())
addFlag(SPDie, dwarf::DW_AT_recursive);
if (DD->getDwarfVersion() >= 5 && SP->isDeleted())
addFlag(SPDie, dwarf::DW_AT_deleted);
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 DefaultLowerBound = getDefaultLowerBound();
auto AddBoundTypeEntry = [&](dwarf::Attribute Attr,
DISubrange::BoundType Bound) -> void {
if (auto *BV = Bound.dyn_cast<DIVariable *>()) {
if (auto *VarDIE = getDIE(BV))
addDIEEntry(DW_Subrange, Attr, *VarDIE);
} else if (auto *BE = Bound.dyn_cast<DIExpression *>()) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, getCU(), *Loc);
addBlock(DW_Subrange, Attr, DwarfExpr.finalize());
} else if (auto *BI = Bound.dyn_cast<ConstantInt *>()) {
if (Attr == dwarf::DW_AT_count) {
if (BI->getSExtValue() != -1)
addUInt(DW_Subrange, Attr, None, BI->getSExtValue());
} else if (Attr != dwarf::DW_AT_lower_bound || DefaultLowerBound == -1 ||
BI->getSExtValue() != DefaultLowerBound)
addSInt(DW_Subrange, Attr, dwarf::DW_FORM_sdata, BI->getSExtValue());
AddBoundTypeEntry(dwarf::DW_AT_lower_bound, SR->getLowerBound());
AddBoundTypeEntry(dwarf::DW_AT_count, SR->getCount());
AddBoundTypeEntry(dwarf::DW_AT_upper_bound, SR->getUpperBound());
AddBoundTypeEntry(dwarf::DW_AT_byte_stride, SR->getStride());
void DwarfUnit::constructGenericSubrangeDIE(DIE &Buffer,
const DIGenericSubrange *GSR,
DIE *IndexTy) {
DIE &DwGenericSubrange =
createAndAddDIE(dwarf::DW_TAG_generic_subrange, Buffer);
addDIEEntry(DwGenericSubrange, dwarf::DW_AT_type, *IndexTy);
int64_t DefaultLowerBound = getDefaultLowerBound();
auto AddBoundTypeEntry = [&](dwarf::Attribute Attr,
DIGenericSubrange::BoundType Bound) -> void {
if (auto *BV = Bound.dyn_cast<DIVariable *>()) {
if (auto *VarDIE = getDIE(BV))
addDIEEntry(DwGenericSubrange, Attr, *VarDIE);
} else if (auto *BE = Bound.dyn_cast<DIExpression *>()) {
if (BE->isConstant() &&
DIExpression::SignedOrUnsignedConstant::SignedConstant ==
*BE->isConstant()) {
if (Attr != dwarf::DW_AT_lower_bound || DefaultLowerBound == -1 ||
static_cast<int64_t>(BE->getElement(1)) != DefaultLowerBound)
addSInt(DwGenericSubrange, Attr, dwarf::DW_FORM_sdata,
} else {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, getCU(), *Loc);
addBlock(DwGenericSubrange, Attr, DwarfExpr.finalize());
AddBoundTypeEntry(dwarf::DW_AT_lower_bound, GSR->getLowerBound());
AddBoundTypeEntry(dwarf::DW_AT_count, GSR->getCount());
AddBoundTypeEntry(dwarf::DW_AT_upper_bound, GSR->getUpperBound());
AddBoundTypeEntry(dwarf::DW_AT_byte_stride, GSR->getStride());
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();
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 NumVecElements =
? Subrange->getCount().get<ConstantInt *>()->getSExtValue()
: 0;
// 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);
if (DIVariable *Var = CTy->getDataLocation()) {
if (auto *VarDIE = getDIE(Var))
addDIEEntry(Buffer, dwarf::DW_AT_data_location, *VarDIE);
} else if (DIExpression *Expr = CTy->getDataLocationExp()) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, getCU(), *Loc);
addBlock(Buffer, dwarf::DW_AT_data_location, DwarfExpr.finalize());
if (DIVariable *Var = CTy->getAssociated()) {
if (auto *VarDIE = getDIE(Var))
addDIEEntry(Buffer, dwarf::DW_AT_associated, *VarDIE);
} else if (DIExpression *Expr = CTy->getAssociatedExp()) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, getCU(), *Loc);
addBlock(Buffer, dwarf::DW_AT_associated, DwarfExpr.finalize());
if (DIVariable *Var = CTy->getAllocated()) {
if (auto *VarDIE = getDIE(Var))
addDIEEntry(Buffer, dwarf::DW_AT_allocated, *VarDIE);
} else if (DIExpression *Expr = CTy->getAllocatedExp()) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, getCU(), *Loc);
addBlock(Buffer, dwarf::DW_AT_allocated, DwarfExpr.finalize());
if (auto *RankConst = CTy->getRankConst()) {
addSInt(Buffer, dwarf::DW_AT_rank, dwarf::DW_FORM_sdata,
} else if (auto *RankExpr = CTy->getRankExp()) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, getCU(), *Loc);
addBlock(Buffer, dwarf::DW_AT_rank, DwarfExpr.finalize());
// Emit the element type.
addType(Buffer, 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 (DINode *E : Elements) {
// FIXME: Should this really be such a loose cast?
if (auto *Element = dyn_cast_or_null<DINode>(E)) {
if (Element->getTag() == dwarf::DW_TAG_subrange_type)
constructSubrangeDIE(Buffer, cast<DISubrange>(Element), IdxTy);
else if (Element->getTag() == dwarf::DW_TAG_generic_subrange)
constructGenericSubrangeDIE(Buffer, cast<DIGenericSubrange>(Element),
void DwarfUnit::constructEnumTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
const DIType *DTy = CTy->getBaseType();
bool IsUnsigned = DTy && DD->isUnsignedDIType(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);
auto *Context = CTy->getScope();
bool IndexEnumerators = !Context || isa<DICompileUnit>(Context) || isa<DIFile>(Context) ||
isa<DINamespace>(Context) || isa<DICommonBlock>(Context);
DINodeArray Elements = CTy->getElements();
// Add enumerators to enumeration type.
for (const DINode *E : Elements) {
auto *Enum = dyn_cast_or_null<DIEnumerator>(E);
if (Enum) {
DIE &Enumerator = createAndAddDIE(dwarf::DW_TAG_enumerator, Buffer);
StringRef Name = Enum->getName();
addString(Enumerator, dwarf::DW_AT_name, Name);
addConstantValue(Enumerator, Enum->getValue(), IsUnsigned);
if (IndexEnumerators)
addGlobalName(Name, Enumerator, Context);
void DwarfUnit::constructContainingTypeDIEs() {
for (auto &P : ContainingTypeMap) {
DIE &SPDie = *P.first;
const DINode *D = P.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);
addAnnotation(MemberDie, DT->getAnnotations());
if (DIType *Resolved = 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()) {
// In DWARF v3, DW_FORM_data4/8 in DW_AT_data_member_location are
// interpreted as location-list pointers. Interpreting constants as
// pointers is not expected, so we use DW_FORM_udata to encode the
// constants here.
if (DD->getDwarfVersion() == 3)
addUInt(MemberDie, dwarf::DW_AT_data_member_location,
dwarf::DW_FORM_udata, OffsetInBytes);
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))
addAttribute(MemberDie, 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(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 = 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
if (!DD->useSectionsAsReferences())
EndLabel = Asm->emitDwarfUnitLength(
isDwoUnit() ? "debug_info_dwo" : "debug_info", "Length of Unit");
Asm->emitDwarfUnitLength(getHeaderSize() + getUnitDie().getSize(),
"Length of Unit");
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->emitDwarfLengthOrOffset(Ty ? Ty->getOffset() : 0);
void DwarfUnit::addSectionDelta(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Hi, const MCSymbol *Lo) {
addAttribute(Die, Attribute, DD->getDwarfSectionOffsetForm(),
new (DIEValueAllocator) DIEDelta(Hi, Lo));
void DwarfUnit::addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label, const MCSymbol *Sec) {
if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
addLabel(Die, Attribute, DD->getDwarfSectionOffsetForm(), Label);
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 DwarfTypeUnit::finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) {
addFlag(D, dwarf::DW_AT_declaration);
StringRef Name = CTy->getName();
if (!Name.empty())
addString(D, dwarf::DW_AT_name, Name);