llvm-6502/lib/CodeGen/AsmPrinter/DwarfDebug.h
Adrian Prantl 7b98f2d2a6 Debug Info: Support variables that are described by more than one MMI
table entry. This happens when SROA splits up an alloca and the resulting
allocas cannot be lowered to SSA values because their address is passed
to a function.

Fixes PR22502.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228764 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-10 23:18:28 +00:00

666 lines
24 KiB
C++

//===-- 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 "AsmPrinterHandler.h"
#include "DbgValueHistoryCalculator.h"
#include "DebugLocEntry.h"
#include "DebugLocList.h"
#include "DwarfAccelTable.h"
#include "DwarfFile.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/FoldingSet.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 <memory>
namespace llvm {
class AsmPrinter;
class ByteStreamer;
class ConstantInt;
class ConstantFP;
class DwarfCompileUnit;
class DwarfDebug;
class DwarfTypeUnit;
class DwarfUnit;
class MachineModuleInfo;
//===----------------------------------------------------------------------===//
/// \brief This class is used to record source line correspondence.
class SrcLineInfo {
unsigned Line; // Source line number.
unsigned Column; // Source column.
unsigned SourceID; // Source ID number.
MCSymbol *Label; // Label in code ID number.
public:
SrcLineInfo(unsigned L, unsigned C, unsigned S, MCSymbol *label)
: Line(L), Column(C), SourceID(S), Label(label) {}
// Accessors
unsigned getLine() const { return Line; }
unsigned getColumn() const { return Column; }
unsigned getSourceID() const { return SourceID; }
MCSymbol *getLabel() const { return Label; }
};
//===----------------------------------------------------------------------===//
/// \brief This class is used to track local variable information.
///
/// - Variables whose location changes over time have a DotDebugLocOffset and the
/// other fields are not used.
///
/// - Variables that are described by multiple MMI table entries have multiple
/// expressions and frame indices.
class DbgVariable {
DIVariable Var; /// Variable Descriptor.
SmallVector<DIExpression, 1> Expr; /// Complex address location expression.
DIE *TheDIE; /// Variable DIE.
unsigned DotDebugLocOffset; /// Offset in DotDebugLocEntries.
const MachineInstr *MInsn; /// DBG_VALUE instruction of the variable.
SmallVector<int, 1> FrameIndex; /// Frame index of the variable.
DwarfDebug *DD;
public:
/// Construct a DbgVariable from a DIVariable.
DbgVariable(DIVariable V, DIExpression E, DwarfDebug *DD, int FI = ~0)
: Var(V), Expr(1, E), TheDIE(nullptr), DotDebugLocOffset(~0U),
MInsn(nullptr), DD(DD) {
FrameIndex.push_back(FI);
assert(Var.Verify() && E.Verify());
}
/// Construct a DbgVariable from a DEBUG_VALUE.
/// AbstractVar may be NULL.
DbgVariable(const MachineInstr *DbgValue, DwarfDebug *DD)
: Var(DbgValue->getDebugVariable()), Expr(1, DbgValue->getDebugExpression()),
TheDIE(nullptr), DotDebugLocOffset(~0U), MInsn(DbgValue), DD(DD) {
FrameIndex.push_back(~0);
}
// Accessors.
DIVariable getVariable() const { return Var; }
const ArrayRef<DIExpression> getExpression() const { return Expr; }
void setDIE(DIE &D) { TheDIE = &D; }
DIE *getDIE() const { return TheDIE; }
void setDotDebugLocOffset(unsigned O) { DotDebugLocOffset = O; }
unsigned getDotDebugLocOffset() const { return DotDebugLocOffset; }
StringRef getName() const { return Var.getName(); }
const MachineInstr *getMInsn() const { return MInsn; }
const ArrayRef<int> getFrameIndex() const { return FrameIndex; }
void addMMIEntry(const DbgVariable &V) {
assert( DotDebugLocOffset == ~0U && !MInsn && "not an MMI entry");
assert(V.DotDebugLocOffset == ~0U && !V.MInsn && "not an MMI entry");
assert(V.Var == Var && "conflicting DIVariable");
if (V.getFrameIndex().back() != ~0) {
auto E = V.getExpression();
auto FI = V.getFrameIndex();
Expr.append(E.begin(), E.end());
FrameIndex.append(FI.begin(), FI.end());
}
assert(Expr.size() > 1
? std::all_of(Expr.begin(), Expr.end(),
[](DIExpression &E) { return E.isBitPiece(); })
: (true && "conflicting locations for variable"));
}
// Translate tag to proper Dwarf tag.
dwarf::Tag getTag() const {
if (Var.getTag() == dwarf::DW_TAG_arg_variable)
return dwarf::DW_TAG_formal_parameter;
return dwarf::DW_TAG_variable;
}
/// \brief 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 variableHasComplexAddress() const {
assert(Var.isVariable() && "Invalid complex DbgVariable!");
assert(Expr.size() == 1 &&
"variableHasComplexAddress() invoked on multi-FI variable");
return Expr.back().getNumElements() > 0;
}
bool isBlockByrefVariable() const;
DIType getType() const;
private:
/// resolve - Look in the DwarfDebug map for the MDNode that
/// corresponds to the reference.
template <typename T> T resolve(DIRef<T> Ref) const;
};
/// \brief 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;
};
/// \brief Collects and handles dwarf debug information.
class DwarfDebug : public AsmPrinterHandler {
// Target of Dwarf emission.
AsmPrinter *Asm;
// Collected machine module information.
MachineModuleInfo *MMI;
// All DIEValues are allocated through this allocator.
BumpPtrAllocator DIEValueAllocator;
// Maps MDNode with its corresponding DwarfCompileUnit.
MapVector<const MDNode *, DwarfCompileUnit *> CUMap;
// Maps subprogram MDNode with its corresponding DwarfCompileUnit.
MapVector<const MDNode *, DwarfCompileUnit *> SPMap;
// 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;
// Provides a unique id per text section.
typedef DenseMap<const MCSection *, SmallVector<SymbolCU, 8> > SectionMapType;
SectionMapType SectionMap;
LexicalScopes LScopes;
// 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.
SmallVector<DebugLocList, 4> DotDebugLocEntries;
// This is a collection of subprogram MDNodes that are processed to
// create DIEs.
SmallPtrSet<const MDNode *, 16> ProcessedSPNodes;
// Maps instruction with label emitted before instruction.
DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
// Maps instruction with label emitted after instruction.
DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
// History of DBG_VALUE and clobber instructions for each user variable.
// Variables are listed in order of appearance.
DbgValueHistoryMap DbgValues;
// Previous instruction's location information. This is used to determine
// label location to indicate scope boundries in dwarf debug info.
DebugLoc PrevInstLoc;
MCSymbol *PrevLabel;
// This location indicates end of function prologue and beginning of function
// body.
DebugLoc PrologEndLoc;
// If nonnull, stores the current machine function we're processing.
const MachineFunction *CurFn;
// If nonnull, stores the current machine instruction we're processing.
const MachineInstr *CurMI;
// If nonnull, stores the CU in which the previous subprogram was contained.
const DwarfCompileUnit *PrevCU;
// Section Symbols: these are assembler temporary labels that are emitted at
// the beginning of each supported dwarf section. These are used to form
// section offsets and are created by EmitSectionLabels.
MCSymbol *DwarfInfoSectionSym, *DwarfAbbrevSectionSym;
MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym, *DwarfAddrSectionSym;
MCSymbol *FunctionBeginSym, *FunctionEndSym;
MCSymbol *DwarfInfoDWOSectionSym, *DwarfAbbrevDWOSectionSym;
MCSymbol *DwarfTypesDWOSectionSym;
MCSymbol *DwarfStrDWOSectionSym;
MCSymbol *DwarfGnuPubNamesSectionSym, *DwarfGnuPubTypesSectionSym;
// 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;
// Counter for assigning globally unique IDs for ranges.
unsigned GlobalRangeCount;
// 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.
// Holder for imported entities.
typedef SmallVector<std::pair<const MDNode *, const MDNode *>, 32>
ImportedEntityMap;
ImportedEntityMap ScopesWithImportedEntities;
// Map from MDNodes for user-defined types to the type units that describe
// them.
DenseMap<const MDNode *, const DwarfTypeUnit *> DwarfTypeUnits;
SmallVector<std::pair<std::unique_ptr<DwarfTypeUnit>, DICompositeType>, 1> TypeUnitsUnderConstruction;
// Whether to emit the pubnames/pubtypes sections.
bool HasDwarfPubSections;
// Whether or not to use AT_ranges for compilation units.
bool HasCURanges;
// Whether we emitted a function into a section other than the default
// text.
bool UsedNonDefaultText;
// Version of dwarf we're emitting.
unsigned DwarfVersion;
// Maps from a type identifier to the actual MDNode.
DITypeIdentifierMap TypeIdentifierMap;
// DWARF5 Experimental Options
bool HasDwarfAccelTables;
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;
DenseMap<const Function *, DISubprogram> FunctionDIs;
MCDwarfDwoLineTable *getDwoLineTable(const DwarfCompileUnit &);
const SmallVectorImpl<std::unique_ptr<DwarfUnit>> &getUnits() {
return InfoHolder.getUnits();
}
/// \brief Find abstract variable associated with Var.
DbgVariable *getExistingAbstractVariable(const DIVariable &DV,
DIVariable &Cleansed);
DbgVariable *getExistingAbstractVariable(const DIVariable &DV);
void createAbstractVariable(const DIVariable &DV, LexicalScope *Scope);
void ensureAbstractVariableIsCreated(const DIVariable &Var,
const MDNode *Scope);
void ensureAbstractVariableIsCreatedIfScoped(const DIVariable &Var,
const MDNode *Scope);
/// \brief Construct a DIE for this abstract scope.
void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
/// \brief Emit initial Dwarf sections with a label at the start of each one.
void emitSectionLabels();
/// \brief Compute the size and offset of a DIE given an incoming Offset.
unsigned computeSizeAndOffset(DIE *Die, unsigned Offset);
/// \brief Compute the size and offset of all the DIEs.
void computeSizeAndOffsets();
/// \brief Collect info for variables that were optimized out.
void collectDeadVariables();
void finishVariableDefinitions();
void finishSubprogramDefinitions();
/// \brief Finish off debug information after all functions have been
/// processed.
void finalizeModuleInfo();
/// \brief Emit labels to close any remaining sections that have been left
/// open.
void endSections();
/// \brief Emit the debug info section.
void emitDebugInfo();
/// \brief Emit the abbreviation section.
void emitAbbreviations();
/// \brief Emit the last address of the section and the end of
/// the line matrix.
void emitEndOfLineMatrix(unsigned SectionEnd);
/// \brief Emit a specified accelerator table.
void emitAccel(DwarfAccelTable &Accel, const MCSection *Section,
StringRef TableName, StringRef SymName);
/// \brief Emit visible names into a hashed accelerator table section.
void emitAccelNames();
/// \brief Emit objective C classes and categories into a hashed
/// accelerator table section.
void emitAccelObjC();
/// \brief Emit namespace dies into a hashed accelerator table.
void emitAccelNamespaces();
/// \brief Emit type dies into a hashed accelerator table.
void emitAccelTypes();
/// \brief 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);
/// \brief 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, const MCSection *PSec, StringRef Name,
const StringMap<const DIE *> &(DwarfCompileUnit::*Accessor)() const);
/// \brief Emit visible names into a debug str section.
void emitDebugStr();
/// \brief Emit visible names into a debug loc section.
void emitDebugLoc();
/// \brief Emit visible names into a debug loc dwo section.
void emitDebugLocDWO();
/// \brief Emit visible names into a debug aranges section.
void emitDebugARanges();
/// \brief Emit visible names into a debug ranges section.
void emitDebugRanges();
/// \brief Emit inline info using custom format.
void emitDebugInlineInfo();
/// DWARF 5 Experimental Split Dwarf Emitters
/// \brief Initialize common features of skeleton units.
void initSkeletonUnit(const DwarfUnit &U, DIE &Die,
std::unique_ptr<DwarfUnit> NewU);
/// \brief Construct the split debug info compile unit for the debug info
/// section.
DwarfCompileUnit &constructSkeletonCU(const DwarfCompileUnit &CU);
/// \brief Construct the split debug info compile unit for the debug info
/// section.
DwarfTypeUnit &constructSkeletonTU(DwarfTypeUnit &TU);
/// \brief Emit the debug info dwo section.
void emitDebugInfoDWO();
/// \brief Emit the debug abbrev dwo section.
void emitDebugAbbrevDWO();
/// \brief Emit the debug line dwo section.
void emitDebugLineDWO();
/// \brief 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;
/// \brief Create new DwarfCompileUnit for the given metadata node with tag
/// DW_TAG_compile_unit.
DwarfCompileUnit &constructDwarfCompileUnit(DICompileUnit DIUnit);
/// \brief Construct imported_module or imported_declaration DIE.
void constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
const MDNode *N);
/// \brief 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);
/// \brief Indentify instructions that are marking the beginning of or
/// ending of a scope.
void identifyScopeMarkers();
/// \brief Populate LexicalScope entries with variables' info.
void collectVariableInfo(DwarfCompileUnit &TheCU, DISubprogram SP,
SmallPtrSetImpl<const MDNode *> &ProcessedVars);
/// \brief 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);
/// \brief Collect variable information from the side table maintained
/// by MMI.
void collectVariableInfoFromMMITable(SmallPtrSetImpl<const MDNode *> &P);
/// \brief Ensure that a label will be emitted before MI.
void requestLabelBeforeInsn(const MachineInstr *MI) {
LabelsBeforeInsn.insert(std::make_pair(MI, nullptr));
}
/// \brief Ensure that a label will be emitted after MI.
void requestLabelAfterInsn(const MachineInstr *MI) {
LabelsAfterInsn.insert(std::make_pair(MI, nullptr));
}
public:
//===--------------------------------------------------------------------===//
// Main entry points.
//
DwarfDebug(AsmPrinter *A, Module *M);
~DwarfDebug() override;
/// \brief Emit all Dwarf sections that should come prior to the
/// content.
void beginModule();
/// \brief Emit all Dwarf sections that should come after the content.
void endModule() override;
/// \brief Gather pre-function debug information.
void beginFunction(const MachineFunction *MF) override;
/// \brief Gather and emit post-function debug information.
void endFunction(const MachineFunction *MF) override;
/// \brief Process beginning of an instruction.
void beginInstruction(const MachineInstr *MI) override;
/// \brief Process end of an instruction.
void endInstruction() override;
/// \brief 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, DICompositeType CTy);
/// \brief Add a label so that arange data can be generated for it.
void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }
/// \brief 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;
}
/// \brief Recursively Emits a debug information entry.
void emitDIE(DIE &Die);
// Experimental DWARF5 features.
/// \brief Returns whether or not to emit tables that dwarf consumers can
/// use to accelerate lookup.
bool useDwarfAccelTables() const { return HasDwarfAccelTables; }
/// \brief 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 section symbol for the .debug_loc section.
MCSymbol *getDebugLocSym() const { return DwarfDebugLocSectionSym; }
/// Returns the section symbol for the .debug_str section.
MCSymbol *getDebugStrSym() const { return DwarfStrSectionSym; }
/// Returns the section symbol for the .debug_ranges section.
MCSymbol *getRangeSectionSym() const { return DwarfDebugRangeSectionSym; }
/// 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 SmallVectorImpl<DebugLocList> &
getDebugLocEntries() const {
return DotDebugLocEntries;
}
/// \brief 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 DebugLocEntry &Entry);
/// \brief emit a single value for the debug loc section.
void emitDebugLocValue(ByteStreamer &Streamer,
const DebugLocEntry::Value &Value,
unsigned PieceOffsetInBits = 0);
/// Emits an optimal (=sorted) sequence of DW_OP_pieces.
void emitLocPieces(ByteStreamer &Streamer,
const DITypeIdentifierMap &Map,
ArrayRef<DebugLocEntry::Value> Values);
/// Emit the location for a debug loc entry, including the size header.
void emitDebugLocEntryLocation(const DebugLocEntry &Entry);
/// Find the MDNode for the given reference.
template <typename T> T resolve(DIRef<T> Ref) const {
return Ref.resolve(TypeIdentifierMap);
}
/// \brief Return the TypeIdentifierMap.
const DITypeIdentifierMap &getTypeIdentifierMap() const {
return TypeIdentifierMap;
}
/// Find the DwarfCompileUnit for the given CU Die.
DwarfCompileUnit *lookupUnit(const DIE *CU) const {
return CUDieMap.lookup(CU);
}
/// isSubprogramContext - Return true if Context is either a subprogram
/// or another context nested inside a subprogram.
bool isSubprogramContext(const MDNode *Context);
void addSubprogramNames(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; }
const MCSymbol *getFunctionBeginSym() const { return FunctionBeginSym; }
const MCSymbol *getFunctionEndSym() const { return FunctionEndSym; }
iterator_range<ImportedEntityMap::const_iterator>
findImportedEntitiesForScope(const MDNode *Scope) const {
return make_range(std::equal_range(
ScopesWithImportedEntities.begin(), ScopesWithImportedEntities.end(),
std::pair<const MDNode *, const MDNode *>(Scope, nullptr),
less_first()));
}
/// \brief A helper function to check whether the DIE for a given Scope is
/// going to be null.
bool isLexicalScopeDIENull(LexicalScope *Scope);
/// \brief Return Label preceding the instruction.
MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
/// \brief Return Label immediately following the instruction.
MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
// FIXME: Consider rolling ranges up into DwarfDebug since we use a single
// range_base anyway, so there's no need to keep them as separate per-CU range
// lists. (though one day we might end up with a range.dwo section, in which
// case it'd go to DwarfFile)
unsigned getNextRangeNumber() { return GlobalRangeCount++; }
// FIXME: Sink these functions down into DwarfFile/Dwarf*Unit.
SmallPtrSet<const MDNode *, 16> &getProcessedSPNodes() {
return ProcessedSPNodes;
}
};
} // End of namespace llvm
#endif