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//===- llvm/CodeGen/DwarfCompileUnit.cpp - Dwarf 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 "DwarfCompileUnit.h"
#include "AddressPool.h"
#include "DwarfDebug.h"
#include "DwarfExpression.h"
#include "DwarfUnit.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/DIE.h"
#include "llvm/CodeGen/LexicalScopes.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/MC/MachineLocation.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/Casting.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <iterator>
#include <memory>
#include <string>
#include <utility>
using namespace llvm;
DwarfCompileUnit::DwarfCompileUnit(unsigned UID, const DICompileUnit *Node,
AsmPrinter *A, DwarfDebug *DW,
DwarfFile *DWU)
: DwarfUnit(dwarf::DW_TAG_compile_unit, Node, A, DW, DWU), UniqueID(UID) {
insertDIE(Node, &getUnitDie());
MacroLabelBegin = Asm->createTempSymbol("cu_macro_begin");
/// addLabelAddress - Add a dwarf label attribute data and value using
/// DW_FORM_addr or DW_FORM_GNU_addr_index.
void DwarfCompileUnit::addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label) {
// Don't use the address pool in non-fission or in the skeleton unit itself.
// FIXME: Once GDB supports this, it's probably worthwhile using the address
// pool from the skeleton - maybe even in non-fission (possibly fewer
// relocations by sharing them in the pool, but we have other ideas about how
// to reduce the number of relocations as well/instead).
if (!DD->useSplitDwarf() || !Skeleton)
return addLocalLabelAddress(Die, Attribute, Label);
if (Label)
DD->addArangeLabel(SymbolCU(this, Label));
unsigned idx = DD->getAddressPool().getIndex(Label);
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_GNU_addr_index,
void DwarfCompileUnit::addLocalLabelAddress(DIE &Die,
dwarf::Attribute Attribute,
const MCSymbol *Label) {
if (Label)
DD->addArangeLabel(SymbolCU(this, Label));
if (Label)
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
unsigned DwarfCompileUnit::getOrCreateSourceID(StringRef FileName,
StringRef DirName) {
// If we print assembly, we can't separate .file entries according to
// compile units. Thus all files will belong to the default compile unit.
// FIXME: add a better feature test than hasRawTextSupport. Even better,
// extend .file to support this.
return Asm->OutStreamer->EmitDwarfFileDirective(
0, DirName, FileName,
Asm->OutStreamer->hasRawTextSupport() ? 0 : getUniqueID());
DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
const DIGlobalVariable *GV, ArrayRef<GlobalExpr> GlobalExprs) {
// Check for pre-existence.
if (DIE *Die = getDIE(GV))
return Die;
auto *GVContext = GV->getScope();
auto *GTy = DD->resolve(GV->getType());
// Construct the context before querying for the existence of the DIE in
// case such construction creates the DIE.
DIE *ContextDIE = getOrCreateContextDIE(GVContext);
// Add to map.
DIE *VariableDIE = &createAndAddDIE(GV->getTag(), *ContextDIE, GV);
DIScope *DeclContext;
if (auto *SDMDecl = GV->getStaticDataMemberDeclaration()) {
DeclContext = resolve(SDMDecl->getScope());
assert(SDMDecl->isStaticMember() && "Expected static member decl");
// We need the declaration DIE that is in the static member's class.
DIE *VariableSpecDIE = getOrCreateStaticMemberDIE(SDMDecl);
addDIEEntry(*VariableDIE, dwarf::DW_AT_specification, *VariableSpecDIE);
// If the global variable's type is different from the one in the class
// member type, assume that it's more specific and also emit it.
if (GTy != DD->resolve(SDMDecl->getBaseType()))
addType(*VariableDIE, GTy);
} else {
DeclContext = GV->getScope();
// Add name and type.
addString(*VariableDIE, dwarf::DW_AT_name, GV->getDisplayName());
addType(*VariableDIE, GTy);
// Add scoping info.
if (!GV->isLocalToUnit())
addFlag(*VariableDIE, dwarf::DW_AT_external);
// Add line number info.
addSourceLine(*VariableDIE, GV);
if (!GV->isDefinition())
addFlag(*VariableDIE, dwarf::DW_AT_declaration);
addGlobalName(GV->getName(), *VariableDIE, DeclContext);
if (uint32_t AlignInBytes = GV->getAlignInBytes())
addUInt(*VariableDIE, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
// Add location.
bool addToAccelTable = false;
DIELoc *Loc = nullptr;
std::unique_ptr<DIEDwarfExpression> DwarfExpr;
for (const auto &GE : GlobalExprs) {
const GlobalVariable *Global = GE.Var;
const DIExpression *Expr = GE.Expr;
// For compatibility with DWARF 3 and earlier,
// DW_AT_location(DW_OP_constu, X, DW_OP_stack_value) becomes
// DW_AT_const_value(X).
if (GlobalExprs.size() == 1 && Expr && Expr->isConstant()) {
addToAccelTable = true;
addConstantValue(*VariableDIE, /*Unsigned=*/true, Expr->getElement(1));
// We cannot describe the location of dllimport'd variables: the
// computation of their address requires loads from the IAT.
if (Global && Global->hasDLLImportStorageClass())
// Nothing to describe without address or constant.
if (!Global && (!Expr || !Expr->isConstant()))
if (!Loc) {
addToAccelTable = true;
Loc = new (DIEValueAllocator) DIELoc;
DwarfExpr = llvm::make_unique<DIEDwarfExpression>(*Asm, *this, *Loc);
if (Global) {
const MCSymbol *Sym = Asm->getSymbol(Global);
if (Global->isThreadLocal()) {
if (Asm->TM.Options.EmulatedTLS) {
// TODO: add debug info for emulated thread local mode.
} else {
// FIXME: Make this work with -gsplit-dwarf.
unsigned PointerSize = Asm->getDataLayout().getPointerSize();
assert((PointerSize == 4 || PointerSize == 8) &&
"Add support for other sizes if necessary");
// Based on GCC's support for TLS:
if (!DD->useSplitDwarf()) {
// 1) Start with a constNu of the appropriate pointer size
addUInt(*Loc, dwarf::DW_FORM_data1,
PointerSize == 4 ? dwarf::DW_OP_const4u
: dwarf::DW_OP_const8u);
// 2) containing the (relocated) offset of the TLS variable
// within the module's TLS block.
addExpr(*Loc, dwarf::DW_FORM_udata,
} else {
addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_const_index);
addUInt(*Loc, dwarf::DW_FORM_udata,
DD->getAddressPool().getIndex(Sym, /* TLS */ true));
// 3) followed by an OP to make the debugger do a TLS lookup.
addUInt(*Loc, dwarf::DW_FORM_data1,
DD->useGNUTLSOpcode() ? dwarf::DW_OP_GNU_push_tls_address
: dwarf::DW_OP_form_tls_address);
} else {
DD->addArangeLabel(SymbolCU(this, Sym));
addOpAddress(*Loc, Sym);
if (Expr) {
if (Loc)
addBlock(*VariableDIE, dwarf::DW_AT_location, DwarfExpr->finalize());
if (DD->useAllLinkageNames())
addLinkageName(*VariableDIE, GV->getLinkageName());
if (addToAccelTable) {
DD->addAccelName(GV->getName(), *VariableDIE);
// If the linkage name is different than the name, go ahead and output
// that as well into the name table.
if (GV->getLinkageName() != "" && GV->getName() != GV->getLinkageName())
DD->addAccelName(GV->getLinkageName(), *VariableDIE);
return VariableDIE;
void DwarfCompileUnit::addRange(RangeSpan Range) {
bool SameAsPrevCU = this == DD->getPrevCU();
// If we have no current ranges just add the range and return, otherwise,
// check the current section and CU against the previous section and CU we
// emitted into and the subprogram was contained within. If these are the
// same then extend our current range, otherwise add this as a new range.
if (CURanges.empty() || !SameAsPrevCU ||
(&CURanges.back().getEnd()->getSection() !=
&Range.getEnd()->getSection())) {
void DwarfCompileUnit::initStmtList() {
// Define start line table label for each Compile Unit.
MCSymbol *LineTableStartSym =
// DW_AT_stmt_list is a offset of line number information for this
// compile unit in debug_line section. For split dwarf this is
// left in the skeleton CU and so not included.
// The line table entries are not always emitted in assembly, so it
// is not okay to use line_table_start here.
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
StmtListValue =
addSectionLabel(getUnitDie(), dwarf::DW_AT_stmt_list, LineTableStartSym,
void DwarfCompileUnit::applyStmtList(DIE &D) {
D.addValue(DIEValueAllocator, *StmtListValue);
void DwarfCompileUnit::attachLowHighPC(DIE &D, const MCSymbol *Begin,
const MCSymbol *End) {
assert(Begin && "Begin label should not be null!");
assert(End && "End label should not be null!");
assert(Begin->isDefined() && "Invalid starting label");
assert(End->isDefined() && "Invalid end label");
addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
if (DD->getDwarfVersion() < 4)
addLabelAddress(D, dwarf::DW_AT_high_pc, End);
addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
// Find DIE for the given subprogram and attach appropriate DW_AT_low_pc
// and DW_AT_high_pc attributes. If there are global variables in this
// scope then create and insert DIEs for these variables.
DIE &DwarfCompileUnit::updateSubprogramScopeDIE(const DISubprogram *SP) {
DIE *SPDie = getOrCreateSubprogramDIE(SP, includeMinimalInlineScopes());
attachLowHighPC(*SPDie, Asm->getFunctionBegin(), Asm->getFunctionEnd());
if (DD->useAppleExtensionAttributes() &&
addFlag(*SPDie, dwarf::DW_AT_APPLE_omit_frame_ptr);
// Only include DW_AT_frame_base in full debug info
if (!includeMinimalInlineScopes()) {
const TargetRegisterInfo *RI = Asm->MF->getSubtarget().getRegisterInfo();
MachineLocation Location(RI->getFrameRegister(*Asm->MF));
if (RI->isPhysicalRegister(Location.getReg()))
addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
// Add name to the name table, we do this here because we're guaranteed
// to have concrete versions of our DW_TAG_subprogram nodes.
DD->addSubprogramNames(SP, *SPDie);
return *SPDie;
// Construct a DIE for this scope.
void DwarfCompileUnit::constructScopeDIE(
LexicalScope *Scope, SmallVectorImpl<DIE *> &FinalChildren) {
if (!Scope || !Scope->getScopeNode())
auto *DS = Scope->getScopeNode();
assert((Scope->getInlinedAt() || !isa<DISubprogram>(DS)) &&
"Only handle inlined subprograms here, use "
"constructSubprogramScopeDIE for non-inlined "
SmallVector<DIE *, 8> Children;
// We try to create the scope DIE first, then the children DIEs. This will
// avoid creating un-used children then removing them later when we find out
// the scope DIE is null.
DIE *ScopeDIE;
if (Scope->getParent() && isa<DISubprogram>(DS)) {
ScopeDIE = constructInlinedScopeDIE(Scope);
if (!ScopeDIE)
// We create children when the scope DIE is not null.
createScopeChildrenDIE(Scope, Children);
} else {
// Early exit when we know the scope DIE is going to be null.
if (DD->isLexicalScopeDIENull(Scope))
bool HasNonScopeChildren = false;
// We create children here when we know the scope DIE is not going to be
// null and the children will be added to the scope DIE.
createScopeChildrenDIE(Scope, Children, &HasNonScopeChildren);
// If there are only other scopes as children, put them directly in the
// parent instead, as this scope would serve no purpose.
if (!HasNonScopeChildren) {
ScopeDIE = constructLexicalScopeDIE(Scope);
assert(ScopeDIE && "Scope DIE should not be null.");
// Add children
for (auto &I : Children)
void DwarfCompileUnit::addScopeRangeList(DIE &ScopeDIE,
SmallVector<RangeSpan, 2> Range) {
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
// Emit offset in .debug_range as a relocatable label. emitDIE will handle
// emitting it appropriately.
const MCSymbol *RangeSectionSym =
RangeSpanList List(Asm->createTempSymbol("debug_ranges"), std::move(Range));
// Under fission, ranges are specified by constant offsets relative to the
// CU's DW_AT_GNU_ranges_base.
if (isDwoUnit())
addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
addSectionLabel(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
// Add the range list to the set of ranges to be emitted.
(Skeleton ? Skeleton : this)->CURangeLists.push_back(std::move(List));
void DwarfCompileUnit::attachRangesOrLowHighPC(
DIE &Die, SmallVector<RangeSpan, 2> Ranges) {
if (Ranges.size() == 1) {
const auto &single = Ranges.front();
attachLowHighPC(Die, single.getStart(), single.getEnd());
} else
addScopeRangeList(Die, std::move(Ranges));
void DwarfCompileUnit::attachRangesOrLowHighPC(
DIE &Die, const SmallVectorImpl<InsnRange> &Ranges) {
SmallVector<RangeSpan, 2> List;
for (const InsnRange &R : Ranges)
attachRangesOrLowHighPC(Die, std::move(List));
// This scope represents inlined body of a function. Construct DIE to
// represent this concrete inlined copy of the function.
DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope) {
auto *DS = Scope->getScopeNode();
auto *InlinedSP = getDISubprogram(DS);
// Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
// was inlined from another compile unit.
DIE *OriginDIE = getAbstractSPDies()[InlinedSP];
assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_inlined_subroutine);
addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
// Add the call site information to the DIE.
const DILocation *IA = Scope->getInlinedAt();
addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
getOrCreateSourceID(IA->getFilename(), IA->getDirectory()));
addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, IA->getLine());
if (IA->getDiscriminator() && DD->getDwarfVersion() >= 4)
addUInt(*ScopeDIE, dwarf::DW_AT_GNU_discriminator, None,
// Add name to the name table, we do this here because we're guaranteed
// to have concrete versions of our DW_TAG_inlined_subprogram nodes.
DD->addSubprogramNames(InlinedSP, *ScopeDIE);
return ScopeDIE;
// Construct new DW_TAG_lexical_block for this scope and attach
// DW_AT_low_pc/DW_AT_high_pc labels.
DIE *DwarfCompileUnit::constructLexicalScopeDIE(LexicalScope *Scope) {
if (DD->isLexicalScopeDIENull(Scope))
return nullptr;
auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_lexical_block);
if (Scope->isAbstractScope())
return ScopeDIE;
attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
return ScopeDIE;
/// constructVariableDIE - Construct a DIE for the given DbgVariable.
DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV, bool Abstract) {
auto D = constructVariableDIEImpl(DV, Abstract);
return D;
DIE *DwarfCompileUnit::constructVariableDIEImpl(const DbgVariable &DV,
bool Abstract) {
// Define variable debug information entry.
auto VariableDie = DIE::get(DIEValueAllocator, DV.getTag());
if (Abstract) {
applyVariableAttributes(DV, *VariableDie);
return VariableDie;
// Add variable address.
unsigned Offset = DV.getDebugLocListIndex();
if (Offset != ~0U) {
addLocationList(*VariableDie, dwarf::DW_AT_location, Offset);
return VariableDie;
// Check if variable is described by a DBG_VALUE instruction.
if (const MachineInstr *DVInsn = DV.getMInsn()) {
assert(DVInsn->getNumOperands() == 4);
if (DVInsn->getOperand(0).isReg()) {
auto RegOp = DVInsn->getOperand(0);
auto Op1 = DVInsn->getOperand(1);
// If the second operand is an immediate, this is an indirect value.
assert((!Op1.isImm() || (Op1.getImm() == 0)) && "unexpected offset");
MachineLocation Location(RegOp.getReg(), Op1.isImm());
addVariableAddress(DV, *VariableDie, Location);
} else if (DVInsn->getOperand(0).isImm()) {
// This variable is described by a single constant.
// Check whether it has a DIExpression.
auto *Expr = DV.getSingleExpression();
if (Expr && Expr->getNumElements()) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
// If there is an expression, emit raw unsigned bytes.
addBlock(*VariableDie, dwarf::DW_AT_location, DwarfExpr.finalize());
} else
addConstantValue(*VariableDie, DVInsn->getOperand(0), DV.getType());
} else if (DVInsn->getOperand(0).isFPImm())
addConstantFPValue(*VariableDie, DVInsn->getOperand(0));
else if (DVInsn->getOperand(0).isCImm())
addConstantValue(*VariableDie, DVInsn->getOperand(0).getCImm(),
return VariableDie;
// .. else use frame index.
if (!DV.hasFrameIndexExprs())
return VariableDie;
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
for (auto &Fragment : DV.getFrameIndexExprs()) {
unsigned FrameReg = 0;
const DIExpression *Expr = Fragment.Expr;
const TargetFrameLowering *TFI = Asm->MF->getSubtarget().getFrameLowering();
int Offset = TFI->getFrameIndexReference(*Asm->MF, Fragment.FI, FrameReg);
SmallVector<uint64_t, 8> Ops;
Ops.append(Expr->elements_begin(), Expr->elements_end());
DIExpressionCursor Cursor(Ops);
*Asm->MF->getSubtarget().getRegisterInfo(), Cursor, FrameReg);
addBlock(*VariableDie, dwarf::DW_AT_location, DwarfExpr.finalize());
return VariableDie;
DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV,
const LexicalScope &Scope,
DIE *&ObjectPointer) {
auto Var = constructVariableDIE(DV, Scope.isAbstractScope());
if (DV.isObjectPointer())
ObjectPointer = Var;
return Var;
DIE *DwarfCompileUnit::createScopeChildrenDIE(LexicalScope *Scope,
SmallVectorImpl<DIE *> &Children,
bool *HasNonScopeChildren) {
DIE *ObjectPointer = nullptr;
for (DbgVariable *DV : DU->getScopeVariables().lookup(Scope))
Children.push_back(constructVariableDIE(*DV, *Scope, ObjectPointer));
// Skip imported directives in gmlt-like data.
if (!includeMinimalInlineScopes()) {
// There is no need to emit empty lexical block DIE.
for (const auto *IE : ImportedEntities[Scope->getScopeNode()])
if (HasNonScopeChildren)
*HasNonScopeChildren = !Children.empty();
for (LexicalScope *LS : Scope->getChildren())
constructScopeDIE(LS, Children);
return ObjectPointer;
void DwarfCompileUnit::constructSubprogramScopeDIE(const DISubprogram *Sub, LexicalScope *Scope) {
DIE &ScopeDIE = updateSubprogramScopeDIE(Sub);
if (Scope) {
// Collect lexical scope children first.
// ObjectPointer might be a local (non-argument) local variable if it's a
// block's synthetic this pointer.
if (DIE *ObjectPointer = createAndAddScopeChildren(Scope, ScopeDIE))
addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
// If this is a variadic function, add an unspecified parameter.
DITypeRefArray FnArgs = Sub->getType()->getTypeArray();
// If we have a single element of null, it is a function that returns void.
// If we have more than one elements and the last one is null, it is a
// variadic function.
if (FnArgs.size() > 1 && !FnArgs[FnArgs.size() - 1] &&
DIE::get(DIEValueAllocator, dwarf::DW_TAG_unspecified_parameters));
DIE *DwarfCompileUnit::createAndAddScopeChildren(LexicalScope *Scope,
DIE &ScopeDIE) {
// We create children when the scope DIE is not null.
SmallVector<DIE *, 8> Children;
DIE *ObjectPointer = createScopeChildrenDIE(Scope, Children);
// Add children
for (auto &I : Children)
return ObjectPointer;
void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
LexicalScope *Scope) {
DIE *&AbsDef = getAbstractSPDies()[Scope->getScopeNode()];
if (AbsDef)
auto *SP = cast<DISubprogram>(Scope->getScopeNode());
DIE *ContextDIE;
if (includeMinimalInlineScopes())
ContextDIE = &getUnitDie();
// Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
// the important distinction that the debug node is not associated with the
// DIE (since the debug node will be associated with the concrete DIE, if
// any). It could be refactored to some common utility function.
else if (auto *SPDecl = SP->getDeclaration()) {
ContextDIE = &getUnitDie();
} else
ContextDIE = getOrCreateContextDIE(resolve(SP->getScope()));
// Passing null as the associated node because the abstract definition
// shouldn't be found by lookup.
AbsDef = &createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, nullptr);
applySubprogramAttributesToDefinition(SP, *AbsDef);
if (!includeMinimalInlineScopes())
addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
if (DIE *ObjectPointer = createAndAddScopeChildren(Scope, *AbsDef))
addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
DIE *DwarfCompileUnit::constructImportedEntityDIE(
const DIImportedEntity *Module) {
DIE *IMDie = DIE::get(DIEValueAllocator, (dwarf::Tag)Module->getTag());
insertDIE(Module, IMDie);
DIE *EntityDie;
auto *Entity = resolve(Module->getEntity());
if (auto *NS = dyn_cast<DINamespace>(Entity))
EntityDie = getOrCreateNameSpace(NS);
else if (auto *M = dyn_cast<DIModule>(Entity))
EntityDie = getOrCreateModule(M);
else if (auto *SP = dyn_cast<DISubprogram>(Entity))
EntityDie = getOrCreateSubprogramDIE(SP);
else if (auto *T = dyn_cast<DIType>(Entity))
EntityDie = getOrCreateTypeDIE(T);
else if (auto *GV = dyn_cast<DIGlobalVariable>(Entity))
EntityDie = getOrCreateGlobalVariableDIE(GV, {});
EntityDie = getDIE(Entity);
auto *File = Module->getFile();
addSourceLine(*IMDie, Module->getLine(), File ? File->getFilename() : "",
File ? File->getDirectory() : "");
addDIEEntry(*IMDie, dwarf::DW_AT_import, *EntityDie);
StringRef Name = Module->getName();
if (!Name.empty())
addString(*IMDie, dwarf::DW_AT_name, Name);
return IMDie;
void DwarfCompileUnit::finishSubprogramDefinition(const DISubprogram *SP) {
DIE *D = getDIE(SP);
if (DIE *AbsSPDIE = getAbstractSPDies().lookup(SP)) {
if (D)
// If this subprogram has an abstract definition, reference that
addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
} else {
assert(D || includeMinimalInlineScopes());
if (D)
// And attach the attributes
applySubprogramAttributesToDefinition(SP, *D);
void DwarfCompileUnit::finishVariableDefinition(const DbgVariable &Var) {
DbgVariable *AbsVar = getExistingAbstractVariable(
InlinedVariable(Var.getVariable(), Var.getInlinedAt()));
auto *VariableDie = Var.getDIE();
if (AbsVar && AbsVar->getDIE()) {
addDIEEntry(*VariableDie, dwarf::DW_AT_abstract_origin,
} else
applyVariableAttributes(Var, *VariableDie);
DbgVariable *DwarfCompileUnit::getExistingAbstractVariable(InlinedVariable IV) {
const DILocalVariable *Cleansed;
return getExistingAbstractVariable(IV, Cleansed);
// Find abstract variable, if any, associated with Var.
DbgVariable *DwarfCompileUnit::getExistingAbstractVariable(
InlinedVariable IV, const DILocalVariable *&Cleansed) {
// More then one inlined variable corresponds to one abstract variable.
Cleansed = IV.first;
auto &AbstractVariables = getAbstractVariables();
auto I = AbstractVariables.find(Cleansed);
if (I != AbstractVariables.end())
return I->second.get();
return nullptr;
void DwarfCompileUnit::createAbstractVariable(const DILocalVariable *Var,
LexicalScope *Scope) {
assert(Scope && Scope->isAbstractScope());
auto AbsDbgVariable = llvm::make_unique<DbgVariable>(Var, /* IA */ nullptr);
DU->addScopeVariable(Scope, AbsDbgVariable.get());
getAbstractVariables()[Var] = std::move(AbsDbgVariable);
void DwarfCompileUnit::emitHeader(bool UseOffsets) {
// Don't bother labeling the .dwo unit, as its offset isn't used.
if (!Skeleton) {
LabelBegin = Asm->createTempSymbol("cu_begin");
dwarf::UnitType UT = Skeleton ? dwarf::DW_UT_split_compile
: DD->useSplitDwarf() ? dwarf::DW_UT_skeleton
: dwarf::DW_UT_compile;
DwarfUnit::emitCommonHeader(UseOffsets, UT);
bool DwarfCompileUnit::hasDwarfPubSections() const {
// Opting in to GNU Pubnames/types overrides the default to ensure these are
// generated for things like Gold's gdb_index generation.
if (CUNode->getGnuPubnames())
return true;
return DD->tuneForGDB() && !includeMinimalInlineScopes();
/// addGlobalName - Add a new global name to the compile unit.
void DwarfCompileUnit::addGlobalName(StringRef Name, const DIE &Die,
const DIScope *Context) {
if (!hasDwarfPubSections())
std::string FullName = getParentContextString(Context) + Name.str();
GlobalNames[FullName] = &Die;
void DwarfCompileUnit::addGlobalNameForTypeUnit(StringRef Name,
const DIScope *Context) {
if (!hasDwarfPubSections())
std::string FullName = getParentContextString(Context) + Name.str();
// Insert, allowing the entry to remain as-is if it's already present
// This way the CU-level type DIE is preferred over the "can't describe this
// type as a unit offset because it's not really in the CU at all, it's only
// in a type unit"
GlobalNames.insert(std::make_pair(std::move(FullName), &getUnitDie()));
/// Add a new global type to the unit.
void DwarfCompileUnit::addGlobalType(const DIType *Ty, const DIE &Die,
const DIScope *Context) {
if (!hasDwarfPubSections())
std::string FullName = getParentContextString(Context) + Ty->getName().str();
GlobalTypes[FullName] = &Die;
void DwarfCompileUnit::addGlobalTypeUnitType(const DIType *Ty,
const DIScope *Context) {
if (!hasDwarfPubSections())
std::string FullName = getParentContextString(Context) + Ty->getName().str();
// Insert, allowing the entry to remain as-is if it's already present
// This way the CU-level type DIE is preferred over the "can't describe this
// type as a unit offset because it's not really in the CU at all, it's only
// in a type unit"
GlobalTypes.insert(std::make_pair(std::move(FullName), &getUnitDie()));
/// addVariableAddress - Add DW_AT_location attribute for a
/// DbgVariable based on provided MachineLocation.
void DwarfCompileUnit::addVariableAddress(const DbgVariable &DV, DIE &Die,
MachineLocation Location) {
// addBlockByrefAddress is obsolete and will be removed soon.
// The clang frontend always generates block byref variables with a
// complex expression that encodes exactly what addBlockByrefAddress
// would do.
assert((!DV.isBlockByrefVariable() || DV.hasComplexAddress()) &&
"block byref variable without a complex expression");
if (DV.hasComplexAddress())
addComplexAddress(DV, Die, dwarf::DW_AT_location, Location);
else if (DV.isBlockByrefVariable())
addBlockByrefAddress(DV, Die, dwarf::DW_AT_location, Location);
addAddress(Die, dwarf::DW_AT_location, Location);
/// Add an address attribute to a die based on the location provided.
void DwarfCompileUnit::addAddress(DIE &Die, dwarf::Attribute Attribute,
const MachineLocation &Location) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
if (Location.isIndirect())
DIExpressionCursor Cursor({});
const TargetRegisterInfo &TRI = *Asm->MF->getSubtarget().getRegisterInfo();
if (!DwarfExpr.addMachineRegExpression(TRI, Cursor, Location.getReg()))
// Now attach the location information to the DIE.
addBlock(Die, Attribute, DwarfExpr.finalize());
/// Start with the address based on the location provided, and generate the
/// DWARF information necessary to find the actual variable given the extra
/// address information encoded in the DbgVariable, starting from the starting
/// location. Add the DWARF information to the die.
void DwarfCompileUnit::addComplexAddress(const DbgVariable &DV, DIE &Die,
dwarf::Attribute Attribute,
const MachineLocation &Location) {
DIELoc *Loc = new (DIEValueAllocator) DIELoc;
DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
const DIExpression *DIExpr = DV.getSingleExpression();
if (Location.isIndirect())
DIExpressionCursor Cursor(DIExpr);
const TargetRegisterInfo &TRI = *Asm->MF->getSubtarget().getRegisterInfo();
if (!DwarfExpr.addMachineRegExpression(TRI, Cursor, Location.getReg()))
// Now attach the location information to the DIE.
addBlock(Die, Attribute, DwarfExpr.finalize());
/// Add a Dwarf loclistptr attribute data and value.
void DwarfCompileUnit::addLocationList(DIE &Die, dwarf::Attribute Attribute,
unsigned Index) {
dwarf::Form Form = DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
: dwarf::DW_FORM_data4;
Die.addValue(DIEValueAllocator, Attribute, Form, DIELocList(Index));
void DwarfCompileUnit::applyVariableAttributes(const DbgVariable &Var,
DIE &VariableDie) {
StringRef Name = Var.getName();
if (!Name.empty())
addString(VariableDie, dwarf::DW_AT_name, Name);
const auto *DIVar = Var.getVariable();
if (DIVar)
if (uint32_t AlignInBytes = DIVar->getAlignInBytes())
addUInt(VariableDie, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
addSourceLine(VariableDie, DIVar);
addType(VariableDie, Var.getType());
if (Var.isArtificial())
addFlag(VariableDie, dwarf::DW_AT_artificial);
/// Add a Dwarf expression attribute data and value.
void DwarfCompileUnit::addExpr(DIELoc &Die, dwarf::Form Form,
const MCExpr *Expr) {
Die.addValue(DIEValueAllocator, (dwarf::Attribute)0, Form, DIEExpr(Expr));
void DwarfCompileUnit::applySubprogramAttributesToDefinition(
const DISubprogram *SP, DIE &SPDie) {
auto *SPDecl = SP->getDeclaration();
auto *Context = resolve(SPDecl ? SPDecl->getScope() : SP->getScope());
applySubprogramAttributes(SP, SPDie, includeMinimalInlineScopes());
addGlobalName(SP->getName(), SPDie, Context);
bool DwarfCompileUnit::isDwoUnit() const {
return DD->useSplitDwarf() && Skeleton;
bool DwarfCompileUnit::includeMinimalInlineScopes() const {
return getCUNode()->getEmissionKind() == DICompileUnit::LineTablesOnly ||
(DD->useSplitDwarf() && !Skeleton);