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llvm-project/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

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//===-- llvm/CodeGen/DwarfDebug.h - Dwarf Debug Framework ------*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains support for writing dwarf debug info into asm files.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
#define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
#include "DbgValueHistoryCalculator.h"
#include "DebugHandlerBase.h"
#include "DebugLocStream.h"
#include "DwarfAccelTable.h"
#include "DwarfFile.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/CodeGen/DIE.h"
#include "llvm/CodeGen/LexicalScopes.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DebugLoc.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MachineLocation.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Target/TargetOptions.h"
#include <memory>
namespace llvm {
class AsmPrinter;
class ByteStreamer;
class ConstantInt;
class ConstantFP;
class DebugLocEntry;
class DwarfCompileUnit;
class DwarfDebug;
class DwarfTypeUnit;
class DwarfUnit;
class MachineModuleInfo;
//===----------------------------------------------------------------------===//
/// This class is used to track local variable information.
///
/// Variables can be created from allocas, in which case they're generated from
/// the MMI table. Such variables can have multiple expressions and frame
/// indices. The \a Expr and \a FrameIndices array must match.
///
/// Variables can be created from \c DBG_VALUE instructions. Those whose
/// location changes over time use \a DebugLocListIndex, while those with a
/// single instruction use \a MInsn and (optionally) a single entry of \a Expr.
///
/// Variables that have been optimized out use none of these fields.
class DbgVariable {
const DILocalVariable *Var; /// Variable Descriptor.
const DILocation *IA; /// Inlined at location.
SmallVector<const DIExpression *, 1> Expr; /// Complex address.
DIE *TheDIE = nullptr; /// Variable DIE.
unsigned DebugLocListIndex = ~0u; /// Offset in DebugLocs.
const MachineInstr *MInsn = nullptr; /// DBG_VALUE instruction.
SmallVector<int, 1> FrameIndex; /// Frame index.
public:
/// Construct a DbgVariable.
///
/// Creates a variable without any DW_AT_location. Call \a initializeMMI()
/// for MMI entries, or \a initializeDbgValue() for DBG_VALUE instructions.
DbgVariable(const DILocalVariable *V, const DILocation *IA)
: Var(V), IA(IA) {}
/// Initialize from the MMI table.
void initializeMMI(const DIExpression *E, int FI) {
assert(Expr.empty() && "Already initialized?");
assert(FrameIndex.empty() && "Already initialized?");
assert(!MInsn && "Already initialized?");
assert((!E || E->isValid()) && "Expected valid expression");
assert(~FI && "Expected valid index");
Expr.push_back(E);
FrameIndex.push_back(FI);
}
/// Initialize from a DBG_VALUE instruction.
void initializeDbgValue(const MachineInstr *DbgValue) {
assert(Expr.empty() && "Already initialized?");
assert(FrameIndex.empty() && "Already initialized?");
assert(!MInsn && "Already initialized?");
assert(Var == DbgValue->getDebugVariable() && "Wrong variable");
assert(IA == DbgValue->getDebugLoc()->getInlinedAt() && "Wrong inlined-at");
MInsn = DbgValue;
if (auto *E = DbgValue->getDebugExpression())
if (E->getNumElements())
Expr.push_back(E);
}
// Accessors.
const DILocalVariable *getVariable() const { return Var; }
const DILocation *getInlinedAt() const { return IA; }
ArrayRef<const DIExpression *> getExpression() const { return Expr; }
const DIExpression *getSingleExpression() const {
assert(MInsn && Expr.size() <= 1);
return Expr.size() ? Expr[0] : nullptr;
}
void setDIE(DIE &D) { TheDIE = &D; }
DIE *getDIE() const { return TheDIE; }
void setDebugLocListIndex(unsigned O) { DebugLocListIndex = O; }
unsigned getDebugLocListIndex() const { return DebugLocListIndex; }
StringRef getName() const { return Var->getName(); }
const MachineInstr *getMInsn() const { return MInsn; }
ArrayRef<int> getFrameIndex() const { return FrameIndex; }
void addMMIEntry(const DbgVariable &V) {
assert(DebugLocListIndex == ~0U && !MInsn && "not an MMI entry");
assert(V.DebugLocListIndex == ~0U && !V.MInsn && "not an MMI entry");
assert(V.Var == Var && "conflicting variable");
assert(V.IA == IA && "conflicting inlined-at location");
assert(!FrameIndex.empty() && "Expected an MMI entry");
assert(!V.FrameIndex.empty() && "Expected an MMI entry");
assert(Expr.size() == FrameIndex.size() && "Mismatched expressions");
assert(V.Expr.size() == V.FrameIndex.size() && "Mismatched expressions");
Expr.append(V.Expr.begin(), V.Expr.end());
FrameIndex.append(V.FrameIndex.begin(), V.FrameIndex.end());
assert(all_of(Expr, [](const DIExpression *E) {
return E && E->isBitPiece();
}) && "conflicting locations for variable");
}
// Translate tag to proper Dwarf tag.
dwarf::Tag getTag() const {
// FIXME: Why don't we just infer this tag and store it all along?
if (Var->isParameter())
return dwarf::DW_TAG_formal_parameter;
return dwarf::DW_TAG_variable;
}
/// Return true if DbgVariable is artificial.
bool isArtificial() const {
if (Var->isArtificial())
return true;
if (getType()->isArtificial())
return true;
return false;
}
bool isObjectPointer() const {
if (Var->isObjectPointer())
return true;
if (getType()->isObjectPointer())
return true;
return false;
}
bool hasComplexAddress() const {
assert(MInsn && "Expected DBG_VALUE, not MMI variable");
assert(FrameIndex.empty() && "Expected DBG_VALUE, not MMI variable");
assert(
(Expr.empty() || (Expr.size() == 1 && Expr.back()->getNumElements())) &&
"Invalid Expr for DBG_VALUE");
return !Expr.empty();
}
bool isBlockByrefVariable() const;
const DIType *getType() const;
private:
template <typename T> T *resolve(TypedDINodeRef<T> Ref) const {
return Ref.resolve();
}
};
/// Helper used to pair up a symbol and its DWARF compile unit.
struct SymbolCU {
SymbolCU(DwarfCompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}
const MCSymbol *Sym;
DwarfCompileUnit *CU;
};
/// Collects and handles dwarf debug information.
class DwarfDebug : public DebugHandlerBase {
/// All DIEValues are allocated through this allocator.
BumpPtrAllocator DIEValueAllocator;
/// Maps MDNode with its corresponding DwarfCompileUnit.
MapVector<const MDNode *, DwarfCompileUnit *> CUMap;
/// Maps a CU DIE with its corresponding DwarfCompileUnit.
DenseMap<const DIE *, DwarfCompileUnit *> CUDieMap;
/// List of all labels used in aranges generation.
std::vector<SymbolCU> ArangeLabels;
/// Size of each symbol emitted (for those symbols that have a specific size).
DenseMap<const MCSymbol *, uint64_t> SymSize;
/// Collection of abstract variables.
DenseMap<const MDNode *, std::unique_ptr<DbgVariable>> AbstractVariables;
SmallVector<std::unique_ptr<DbgVariable>, 64> ConcreteVariables;
/// Collection of DebugLocEntry. Stored in a linked list so that DIELocLists
/// can refer to them in spite of insertions into this list.
DebugLocStream DebugLocs;
/// This is a collection of subprogram MDNodes that are processed to
/// create DIEs.
SmallPtrSet<const MDNode *, 16> ProcessedSPNodes;
/// If nonnull, stores the current machine function we're processing.
const MachineFunction *CurFn;
/// If nonnull, stores the CU in which the previous subprogram was contained.
const DwarfCompileUnit *PrevCU;
/// As an optimization, there is no need to emit an entry in the directory
/// table for the same directory as DW_AT_comp_dir.
StringRef CompilationDir;
/// Holder for the file specific debug information.
DwarfFile InfoHolder;
/// Holders for the various debug information flags that we might need to
/// have exposed. See accessor functions below for description.
/// Map from MDNodes for user-defined types to their type signatures. Also
/// used to keep track of which types we have emitted type units for.
DenseMap<const MDNode *, uint64_t> TypeSignatures;
SmallVector<
std::pair<std::unique_ptr<DwarfTypeUnit>, const DICompositeType *>, 1>
TypeUnitsUnderConstruction;
/// Whether to emit the pubnames/pubtypes sections.
bool HasDwarfPubSections;
/// Whether to use the GNU TLS opcode (instead of the standard opcode).
bool UseGNUTLSOpcode;
/// Whether to use DWARF 2 bitfields (instead of the DWARF 4 format).
bool UseDWARF2Bitfields;
/// Whether to emit all linkage names, or just abstract subprograms.
bool UseAllLinkageNames;
/// Version of dwarf we're emitting.
unsigned DwarfVersion;
/// DWARF5 Experimental Options
/// @{
bool HasDwarfAccelTables;
bool HasAppleExtensionAttributes;
bool HasSplitDwarf;
/// Separated Dwarf Variables
/// In general these will all be for bits that are left in the
/// original object file, rather than things that are meant
/// to be in the .dwo sections.
/// Holder for the skeleton information.
DwarfFile SkeletonHolder;
/// Store file names for type units under fission in a line table
/// header that will be emitted into debug_line.dwo.
// FIXME: replace this with a map from comp_dir to table so that we
// can emit multiple tables during LTO each of which uses directory
// 0, referencing the comp_dir of all the type units that use it.
MCDwarfDwoLineTable SplitTypeUnitFileTable;
/// @}
/// True iff there are multiple CUs in this module.
bool SingleCU;
bool IsDarwin;
AddressPool AddrPool;
DwarfAccelTable AccelNames;
DwarfAccelTable AccelObjC;
DwarfAccelTable AccelNamespace;
DwarfAccelTable AccelTypes;
// Identify a debugger for "tuning" the debug info.
DebuggerKind DebuggerTuning;
/// \defgroup DebuggerTuning Predicates to tune DWARF for a given debugger.
///
/// Returns whether we are "tuning" for a given debugger.
/// Should be used only within the constructor, to set feature flags.
/// @{
bool tuneForGDB() const { return DebuggerTuning == DebuggerKind::GDB; }
bool tuneForLLDB() const { return DebuggerTuning == DebuggerKind::LLDB; }
bool tuneForSCE() const { return DebuggerTuning == DebuggerKind::SCE; }
/// @}
MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
const SmallVectorImpl<std::unique_ptr<DwarfCompileUnit>> &getUnits() {
return InfoHolder.getUnits();
}
typedef DbgValueHistoryMap::InlinedVariable InlinedVariable;
/// Find abstract variable associated with Var.
DbgVariable *getExistingAbstractVariable(InlinedVariable IV,
const DILocalVariable *&Cleansed);
DbgVariable *getExistingAbstractVariable(InlinedVariable IV);
void createAbstractVariable(const DILocalVariable *DV, LexicalScope *Scope);
void ensureAbstractVariableIsCreated(InlinedVariable Var,
const MDNode *Scope);
void ensureAbstractVariableIsCreatedIfScoped(InlinedVariable Var,
const MDNode *Scope);
DbgVariable *createConcreteVariable(LexicalScope &Scope, InlinedVariable IV);
/// Construct a DIE for this abstract scope.
void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
void finishVariableDefinitions();
void finishSubprogramDefinitions();
/// Finish off debug information after all functions have been
/// processed.
void finalizeModuleInfo();
/// Emit the debug info section.
void emitDebugInfo();
/// Emit the abbreviation section.
void emitAbbreviations();
/// Emit a specified accelerator table.
void emitAccel(DwarfAccelTable &Accel, MCSection *Section,
StringRef TableName);
/// Emit visible names into a hashed accelerator table section.
void emitAccelNames();
/// Emit objective C classes and categories into a hashed
/// accelerator table section.
void emitAccelObjC();
/// Emit namespace dies into a hashed accelerator table.
void emitAccelNamespaces();
/// Emit type dies into a hashed accelerator table.
void emitAccelTypes();
/// Emit visible names into a debug pubnames section.
/// \param GnuStyle determines whether or not we want to emit
/// additional information into the table ala newer gcc for gdb
/// index.
void emitDebugPubNames(bool GnuStyle = false);
/// Emit visible types into a debug pubtypes section.
/// \param GnuStyle determines whether or not we want to emit
/// additional information into the table ala newer gcc for gdb
/// index.
void emitDebugPubTypes(bool GnuStyle = false);
void emitDebugPubSection(
bool GnuStyle, MCSection *PSec, StringRef Name,
const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const);
/// Emit null-terminated strings into a debug str section.
void emitDebugStr();
/// Emit variable locations into a debug loc section.
void emitDebugLoc();
/// Emit variable locations into a debug loc dwo section.
void emitDebugLocDWO();
/// Emit address ranges into a debug aranges section.
void emitDebugARanges();
/// Emit address ranges into a debug ranges section.
void emitDebugRanges();
/// Emit macros into a debug macinfo section.
void emitDebugMacinfo();
void emitMacro(DIMacro &M);
void emitMacroFile(DIMacroFile &F, DwarfCompileUnit &U);
void handleMacroNodes(DIMacroNodeArray Nodes, DwarfCompileUnit &U);
/// DWARF 5 Experimental Split Dwarf Emitters
/// Initialize common features of skeleton units.
void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
std::unique_ptr<DwarfCompileUnit> NewU);
/// Construct the split debug info compile unit for the debug info
/// section.
DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
/// Emit the debug info dwo section.
void emitDebugInfoDWO();
/// Emit the debug abbrev dwo section.
void emitDebugAbbrevDWO();
/// Emit the debug line dwo section.
void emitDebugLineDWO();
/// Emit the debug str dwo section.
void emitDebugStrDWO();
/// Flags to let the linker know we have emitted new style pubnames. Only
/// emit it here if we don't have a skeleton CU for split dwarf.
void addGnuPubAttributes(DwarfUnit &U, DIE &D) const;
/// Create new DwarfCompileUnit for the given metadata node with tag
/// DW_TAG_compile_unit.
DwarfCompileUnit &constructDwarfCompileUnit(const DICompileUnit *DIUnit);
/// Construct imported_module or imported_declaration DIE.
void constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
const DIImportedEntity *N);
/// Register a source line with debug info. Returns the unique
/// label that was emitted and which provides correspondence to the
/// source line list.
void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
unsigned Flags);
/// Populate LexicalScope entries with variables' info.
void collectVariableInfo(DwarfCompileUnit &TheCU, const DISubprogram *SP,
DenseSet<InlinedVariable> &ProcessedVars);
/// Build the location list for all DBG_VALUEs in the
/// function that describe the same variable.
void buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
const DbgValueHistoryMap::InstrRanges &Ranges);
/// Collect variable information from the side table maintained
/// by MMI.
void collectVariableInfoFromMMITable(DenseSet<InlinedVariable> &P);
public:
//===--------------------------------------------------------------------===//
// Main entry points.
//
DwarfDebug(AsmPrinter *A, Module *M);
~DwarfDebug() override;
/// Emit all Dwarf sections that should come prior to the
/// content.
void beginModule();
/// Emit all Dwarf sections that should come after the content.
void endModule() override;
/// Gather pre-function debug information.
void beginFunction(const MachineFunction *MF) override;
/// Gather and emit post-function debug information.
void endFunction(const MachineFunction *MF) override;
/// Process beginning of an instruction.
void beginInstruction(const MachineInstr *MI) override;
/// Perform an MD5 checksum of \p Identifier and return the lower 64 bits.
static uint64_t makeTypeSignature(StringRef Identifier);
/// Add a DIE to the set of types that we're going to pull into
/// type units.
void addDwarfTypeUnitType(DwarfCompileUnit &CU, StringRef Identifier,
DIE &Die, const DICompositeType *CTy);
/// Add a label so that arange data can be generated for it.
void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }
/// For symbols that have a size designated (e.g. common symbols),
/// this tracks that size.
void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {
SymSize[Sym] = Size;
}
/// Returns whether we should emit all DW_AT_[MIPS_]linkage_name.
/// If not, we still might emit certain cases.
bool useAllLinkageNames() const { return UseAllLinkageNames; }
/// Returns whether to use DW_OP_GNU_push_tls_address, instead of the
/// standard DW_OP_form_tls_address opcode
bool useGNUTLSOpcode() const { return UseGNUTLSOpcode; }
/// Returns whether to use the DWARF2 format for bitfields instyead of the
/// DWARF4 format.
bool useDWARF2Bitfields() const { return UseDWARF2Bitfields; }
// Experimental DWARF5 features.
/// Returns whether or not to emit tables that dwarf consumers can
/// use to accelerate lookup.
bool useDwarfAccelTables() const { return HasDwarfAccelTables; }
bool useAppleExtensionAttributes() const {
return HasAppleExtensionAttributes;
}
/// Returns whether or not to change the current debug info for the
/// split dwarf proposal support.
bool useSplitDwarf() const { return HasSplitDwarf; }
/// Returns the Dwarf Version.
unsigned getDwarfVersion() const { return DwarfVersion; }
/// Returns the previous CU that was being updated
const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
void setPrevCU(const DwarfCompileUnit *PrevCU) { this->PrevCU = PrevCU; }
/// Returns the entries for the .debug_loc section.
const DebugLocStream &getDebugLocs() const { return DebugLocs; }
/// Emit an entry for the debug loc section. This can be used to
/// handle an entry that's going to be emitted into the debug loc section.
void emitDebugLocEntry(ByteStreamer &Streamer,
const DebugLocStream::Entry &Entry);
/// Emit the location for a debug loc entry, including the size header.
void emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry);
/// Find the MDNode for the given reference.
template <typename T> T *resolve(TypedDINodeRef<T> Ref) const {
return Ref.resolve();
}
/// Find the DwarfCompileUnit for the given CU Die.
DwarfCompileUnit *lookupUnit(const DIE *CU) const {
return CUDieMap.lookup(CU);
}
void addSubprogramNames(const DISubprogram *SP, DIE &Die);
AddressPool &getAddressPool() { return AddrPool; }
void addAccelName(StringRef Name, const DIE &Die);
void addAccelObjC(StringRef Name, const DIE &Die);
void addAccelNamespace(StringRef Name, const DIE &Die);
void addAccelType(StringRef Name, const DIE &Die, char Flags);
const MachineFunction *getCurrentFunction() const { return CurFn; }
/// A helper function to check whether the DIE for a given Scope is
/// going to be null.
bool isLexicalScopeDIENull(LexicalScope *Scope);
// FIXME: Sink these functions down into DwarfFile/Dwarf*Unit.
SmallPtrSet<const MDNode *, 16> &getProcessedSPNodes() {
return ProcessedSPNodes;
}
};
} // End of namespace llvm
#endif
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