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//===- llvm/CodeGen/DwarfCompileUnit.h - Dwarf Compile Unit -----*- C++ -*-===//
// 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 writing dwarf compile unit.
#include "DwarfDebug.h"
#include "DwarfUnit.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
#include "llvm/CodeGen/LexicalScopes.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/Support/Casting.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <memory>
namespace llvm {
class AsmPrinter;
class DIE;
class DIELoc;
class DIEValueList;
class DwarfFile;
class GlobalVariable;
class MCExpr;
class MCSymbol;
class MDNode;
enum class UnitKind { Skeleton, Full };
class DwarfCompileUnit final : public DwarfUnit {
/// A numeric ID unique among all CUs in the module
unsigned UniqueID;
bool HasRangeLists = false;
/// The start of the unit line section, this is also
/// reused in appyStmtList.
MCSymbol *LineTableStartSym;
/// Skeleton unit associated with this unit.
DwarfCompileUnit *Skeleton = nullptr;
/// The start of the unit within its section.
MCSymbol *LabelBegin = nullptr;
/// The start of the unit macro info within macro section.
MCSymbol *MacroLabelBegin;
using ImportedEntityList = SmallVector<const MDNode *, 8>;
using ImportedEntityMap = DenseMap<const MDNode *, ImportedEntityList>;
ImportedEntityMap ImportedEntities;
/// GlobalNames - A map of globally visible named entities for this unit.
StringMap<const DIE *> GlobalNames;
/// GlobalTypes - A map of globally visible types for this unit.
StringMap<const DIE *> GlobalTypes;
// List of ranges for a given compile unit.
SmallVector<RangeSpan, 2> CURanges;
// The base address of this unit, if any. Used for relative references in
// ranges/locs.
const MCSymbol *BaseAddress = nullptr;
DenseMap<const MDNode *, DIE *> AbstractSPDies;
DenseMap<const DINode *, std::unique_ptr<DbgEntity>> AbstractEntities;
/// DWO ID for correlating skeleton and split units.
uint64_t DWOId = 0;
/// Construct a DIE for the given DbgVariable without initializing the
/// DbgVariable's DIE reference.
DIE *constructVariableDIEImpl(const DbgVariable &DV, bool Abstract);
bool isDwoUnit() const override;
DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
if (isDwoUnit() && !DD->shareAcrossDWOCUs())
return AbstractSPDies;
return DU->getAbstractSPDies();
DenseMap<const DINode *, std::unique_ptr<DbgEntity>> &getAbstractEntities() {
if (isDwoUnit() && !DD->shareAcrossDWOCUs())
return AbstractEntities;
return DU->getAbstractEntities();
void finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) override;
DwarfCompileUnit(unsigned UID, const DICompileUnit *Node, AsmPrinter *A,
DwarfDebug *DW, DwarfFile *DWU,
UnitKind Kind = UnitKind::Full);
bool hasRangeLists() const { return HasRangeLists; }
unsigned getUniqueID() const { return UniqueID; }
DwarfCompileUnit *getSkeleton() const {
return Skeleton;
bool includeMinimalInlineScopes() const;
void initStmtList();
/// Apply the DW_AT_stmt_list from this compile unit to the specified DIE.
void applyStmtList(DIE &D);
/// Get line table start symbol for this unit.
MCSymbol *getLineTableStartSym() const { return LineTableStartSym; }
/// A pair of GlobalVariable and DIExpression.
struct GlobalExpr {
const GlobalVariable *Var;
const DIExpression *Expr;
struct BaseTypeRef {
BaseTypeRef(unsigned BitSize, dwarf::TypeKind Encoding) :
BitSize(BitSize), Encoding(Encoding) {}
unsigned BitSize;
dwarf::TypeKind Encoding;
DIE *Die = nullptr;
std::vector<BaseTypeRef> ExprRefedBaseTypes;
/// Get or create global variable DIE.
getOrCreateGlobalVariableDIE(const DIGlobalVariable *GV,
ArrayRef<GlobalExpr> GlobalExprs);
DIE *getOrCreateCommonBlock(const DICommonBlock *CB,
ArrayRef<GlobalExpr> GlobalExprs);
void addLocationAttribute(DIE *ToDIE, const DIGlobalVariable *GV,
ArrayRef<GlobalExpr> GlobalExprs);
/// addLabelAddress - Add a dwarf label attribute data and value using
/// either DW_FORM_addr or DW_FORM_GNU_addr_index.
void addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label);
/// addLocalLabelAddress - Add a dwarf label attribute data and value using
/// DW_FORM_addr only.
void addLocalLabelAddress(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label);
DwarfCompileUnit &getCU() override { return *this; }
unsigned getOrCreateSourceID(const DIFile *File) override;
void addImportedEntity(const DIImportedEntity* IE) {
DIScope *Scope = IE->getScope();
assert(Scope && "Invalid Scope encoding!");
if (!isa<DILocalScope>(Scope))
// No need to add imported enities that are not local declaration.
auto *LocalScope = cast<DILocalScope>(Scope)->getNonLexicalBlockFileScope();
/// addRange - Add an address range to the list of ranges for this unit.
void addRange(RangeSpan Range);
void attachLowHighPC(DIE &D, const MCSymbol *Begin, const MCSymbol *End);
/// 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 &updateSubprogramScopeDIE(const DISubprogram *SP);
void constructScopeDIE(LexicalScope *Scope, DIE &ParentScopeDIE);
/// A helper function to construct a RangeSpanList for a given
/// lexical scope.
void addScopeRangeList(DIE &ScopeDIE, SmallVector<RangeSpan, 2> Range);
void attachRangesOrLowHighPC(DIE &D, SmallVector<RangeSpan, 2> Ranges);
void attachRangesOrLowHighPC(DIE &D,
const SmallVectorImpl<InsnRange> &Ranges);
/// This scope represents inlined body of a function. Construct
/// DIE to represent this concrete inlined copy of the function.
DIE *constructInlinedScopeDIE(LexicalScope *Scope);
/// Construct new DW_TAG_lexical_block for this scope and
/// attach DW_AT_low_pc/DW_AT_high_pc labels.
DIE *constructLexicalScopeDIE(LexicalScope *Scope);
/// constructVariableDIE - Construct a DIE for the given DbgVariable.
DIE *constructVariableDIE(DbgVariable &DV, bool Abstract = false);
DIE *constructVariableDIE(DbgVariable &DV, const LexicalScope &Scope,
DIE *&ObjectPointer);
/// Construct a DIE for the given DbgLabel.
DIE *constructLabelDIE(DbgLabel &DL, const LexicalScope &Scope);
void createBaseTypeDIEs();
/// Construct a DIE for this subprogram scope.
DIE &constructSubprogramScopeDIE(const DISubprogram *Sub,
LexicalScope *Scope);
DIE *createAndAddScopeChildren(LexicalScope *Scope, DIE &ScopeDIE);
void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
/// Whether to use the GNU analog for a DWARF5 tag, attribute, or location
/// atom. Only applicable when emitting otherwise DWARF4-compliant debug info.
bool useGNUAnalogForDwarf5Feature() const;
/// This takes a DWARF 5 tag and returns it or a GNU analog.
dwarf::Tag getDwarf5OrGNUTag(dwarf::Tag Tag) const;
/// This takes a DWARF 5 attribute and returns it or a GNU analog.
dwarf::Attribute getDwarf5OrGNUAttr(dwarf::Attribute Attr) const;
/// This takes a DWARF 5 location atom and either returns it or a GNU analog.
dwarf::LocationAtom getDwarf5OrGNULocationAtom(dwarf::LocationAtom Loc) const;
/// Construct a call site entry DIE describing a call within \p Scope to a
/// callee described by \p CalleeSP.
/// \p IsTail specifies whether the call is a tail call.
/// \p PCAddr points to the PC value after the call instruction.
/// \p CallAddr points to the PC value at the call instruction (or is null).
/// \p CallReg is a register location for an indirect call. For direct calls
/// the \p CallReg is set to 0.
DIE &constructCallSiteEntryDIE(DIE &ScopeDIE, const DISubprogram *CalleeSP,
bool IsTail, const MCSymbol *PCAddr,
const MCSymbol *CallAddr, unsigned CallReg);
/// Construct call site parameter DIEs for the \p CallSiteDIE. The \p Params
/// were collected by the \ref collectCallSiteParameters.
/// Note: The order of parameters does not matter, since debuggers recognize
/// call site parameters by the DW_AT_location attribute.
void constructCallSiteParmEntryDIEs(DIE &CallSiteDIE,
SmallVector<DbgCallSiteParam, 4> &Params);
/// Construct import_module DIE.
DIE *constructImportedEntityDIE(const DIImportedEntity *Module);
void finishSubprogramDefinition(const DISubprogram *SP);
void finishEntityDefinition(const DbgEntity *Entity);
/// Find abstract variable associated with Var.
using InlinedEntity = DbgValueHistoryMap::InlinedEntity;
DbgEntity *getExistingAbstractEntity(const DINode *Node);
void createAbstractEntity(const DINode *Node, LexicalScope *Scope);
/// Set the skeleton unit associated with this unit.
void setSkeleton(DwarfCompileUnit &Skel) { Skeleton = &Skel; }
unsigned getHeaderSize() const override {
// DWARF v5 added the DWO ID to the header for split/skeleton units.
unsigned DWOIdSize =
DD->getDwarfVersion() >= 5 && DD->useSplitDwarf() ? sizeof(uint64_t)
: 0;
return DwarfUnit::getHeaderSize() + DWOIdSize;
unsigned getLength() {
return Asm->getUnitLengthFieldByteSize() + // Length field
getHeaderSize() + getUnitDie().getSize();
void emitHeader(bool UseOffsets) override;
/// Add the DW_AT_addr_base attribute to the unit DIE.
void addAddrTableBase();
MCSymbol *getLabelBegin() const {
assert(LabelBegin && "LabelBegin is not initialized");
return LabelBegin;
MCSymbol *getMacroLabelBegin() const {
return MacroLabelBegin;
/// Add a new global name to the compile unit.
void addGlobalName(StringRef Name, const DIE &Die,
const DIScope *Context) override;
/// Add a new global name present in a type unit to this compile unit.
void addGlobalNameForTypeUnit(StringRef Name, const DIScope *Context);
/// Add a new global type to the compile unit.
void addGlobalType(const DIType *Ty, const DIE &Die,
const DIScope *Context) override;
/// Add a new global type present in a type unit to this compile unit.
void addGlobalTypeUnitType(const DIType *Ty, const DIScope *Context);
const StringMap<const DIE *> &getGlobalNames() const { return GlobalNames; }
const StringMap<const DIE *> &getGlobalTypes() const { return GlobalTypes; }
/// Add DW_AT_location attribute for a DbgVariable based on provided
/// MachineLocation.
void addVariableAddress(const DbgVariable &DV, DIE &Die,
MachineLocation Location);
/// Add an address attribute to a die based on the location provided.
void addAddress(DIE &Die, dwarf::Attribute Attribute,
const MachineLocation &Location);
/// Start with the address based on the location provided, and generate the
/// DWARF information necessary to find the actual variable (navigating the
/// extra location information encoded in the type) based on the starting
/// location. Add the DWARF information to the die.
void addComplexAddress(const DbgVariable &DV, DIE &Die,
dwarf::Attribute Attribute,
const MachineLocation &Location);
/// Add a Dwarf loclistptr attribute data and value.
void addLocationList(DIE &Die, dwarf::Attribute Attribute, unsigned Index);
void applyVariableAttributes(const DbgVariable &Var, DIE &VariableDie);
/// Add a Dwarf expression attribute data and value.
void addExpr(DIELoc &Die, dwarf::Form Form, const MCExpr *Expr);
void applySubprogramAttributesToDefinition(const DISubprogram *SP,
DIE &SPDie);
void applyLabelAttributes(const DbgLabel &Label, DIE &LabelDie);
/// getRanges - Get the list of ranges for this unit.
const SmallVectorImpl<RangeSpan> &getRanges() const { return CURanges; }
SmallVector<RangeSpan, 2> takeRanges() { return std::move(CURanges); }
void setBaseAddress(const MCSymbol *Base) { BaseAddress = Base; }
const MCSymbol *getBaseAddress() const { return BaseAddress; }
uint64_t getDWOId() const { return DWOId; }
void setDWOId(uint64_t DwoId) { DWOId = DwoId; }
bool hasDwarfPubSections() const;
void addBaseTypeRef(DIEValueList &Die, int64_t Idx);
} // end namespace llvm