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- //===- lib/MC/MCDwarf.cpp - MCDwarf implementation ------------------------===//
- //
- // The LLVM Compiler Infrastructure
- //
- // This file is distributed under the University of Illinois Open Source
- // License. See LICENSE.TXT for details.
- //
- //===----------------------------------------------------------------------===//
- #include "llvm/MC/MCDwarf.h"
- #include "llvm/ADT/Hashing.h"
- #include "llvm/ADT/SmallString.h"
- #include "llvm/ADT/Twine.h"
- #include "llvm/Config/config.h"
- #include "llvm/MC/MCAsmInfo.h"
- #include "llvm/MC/MCContext.h"
- #include "llvm/MC/MCExpr.h"
- #include "llvm/MC/MCObjectFileInfo.h"
- #include "llvm/MC/MCObjectWriter.h"
- #include "llvm/MC/MCRegisterInfo.h"
- #include "llvm/MC/MCStreamer.h"
- #include "llvm/MC/MCSymbol.h"
- #include "llvm/Support/Debug.h"
- #include "llvm/Support/ErrorHandling.h"
- #include "llvm/Support/LEB128.h"
- #include "llvm/Support/Path.h"
- #include "llvm/Support/SourceMgr.h"
- #include "llvm/Support/raw_ostream.h"
- using namespace llvm;
- // Given a special op, return the address skip amount (in units of
- // DWARF2_LINE_MIN_INSN_LENGTH.
- #define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
- // The maximum address skip amount that can be encoded with a special op.
- #define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
- // First special line opcode - leave room for the standard opcodes.
- // Note: If you want to change this, you'll have to update the
- // "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
- #define DWARF2_LINE_OPCODE_BASE 13
- // Minimum line offset in a special line info. opcode. This value
- // was chosen to give a reasonable range of values.
- #define DWARF2_LINE_BASE -5
- // Range of line offsets in a special line info. opcode.
- #define DWARF2_LINE_RANGE 14
- // Define the architecture-dependent minimum instruction length (in bytes).
- // This value should be rather too small than too big.
- #define DWARF2_LINE_MIN_INSN_LENGTH 1
- // Note: when DWARF2_LINE_MIN_INSN_LENGTH == 1 which is the current setting,
- // this routine is a nop and will be optimized away.
- static inline uint64_t ScaleAddrDelta(uint64_t AddrDelta) {
- if (DWARF2_LINE_MIN_INSN_LENGTH == 1)
- return AddrDelta;
- if (AddrDelta % DWARF2_LINE_MIN_INSN_LENGTH != 0) {
- // TODO: report this error, but really only once.
- ;
- }
- return AddrDelta / DWARF2_LINE_MIN_INSN_LENGTH;
- }
- //
- // This is called when an instruction is assembled into the specified section
- // and if there is information from the last .loc directive that has yet to have
- // a line entry made for it is made.
- //
- void MCLineEntry::Make(MCStreamer *MCOS, const MCSection *Section) {
- if (!MCOS->getContext().getDwarfLocSeen())
- return;
- // Create a symbol at in the current section for use in the line entry.
- MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
- // Set the value of the symbol to use for the MCLineEntry.
- MCOS->EmitLabel(LineSym);
- // Get the current .loc info saved in the context.
- const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
- // Create a (local) line entry with the symbol and the current .loc info.
- MCLineEntry LineEntry(LineSym, DwarfLoc);
- // clear DwarfLocSeen saying the current .loc info is now used.
- MCOS->getContext().ClearDwarfLocSeen();
- // Get the MCLineSection for this section, if one does not exist for this
- // section create it.
- const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
- MCOS->getContext().getMCLineSections();
- MCLineSection *LineSection = MCLineSections.lookup(Section);
- if (!LineSection) {
- // Create a new MCLineSection. This will be deleted after the dwarf line
- // table is created using it by iterating through the MCLineSections
- // DenseMap.
- LineSection = new MCLineSection;
- // Save a pointer to the new LineSection into the MCLineSections DenseMap.
- MCOS->getContext().addMCLineSection(Section, LineSection);
- }
- // Add the line entry to this section's entries.
- LineSection->addLineEntry(LineEntry,
- MCOS->getContext().getDwarfCompileUnitID());
- }
- //
- // This helper routine returns an expression of End - Start + IntVal .
- //
- static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
- const MCSymbol &Start,
- const MCSymbol &End,
- int IntVal) {
- MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
- const MCExpr *Res =
- MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
- const MCExpr *RHS =
- MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
- const MCExpr *Res1 =
- MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
- const MCExpr *Res2 =
- MCConstantExpr::Create(IntVal, MCOS.getContext());
- const MCExpr *Res3 =
- MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
- return Res3;
- }
- //
- // This emits the Dwarf line table for the specified section from the entries
- // in the LineSection.
- //
- static inline void EmitDwarfLineTable(MCStreamer *MCOS,
- const MCSection *Section,
- const MCLineSection *LineSection,
- unsigned CUID) {
- // This LineSection does not contain any LineEntry for the given Compile Unit.
- if (!LineSection->containEntriesForID(CUID))
- return;
- unsigned FileNum = 1;
- unsigned LastLine = 1;
- unsigned Column = 0;
- unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
- unsigned Isa = 0;
- MCSymbol *LastLabel = NULL;
- // Loop through each MCLineEntry and encode the dwarf line number table.
- for (MCLineSection::const_iterator
- it = LineSection->getMCLineEntries(CUID).begin(),
- ie = LineSection->getMCLineEntries(CUID).end(); it != ie; ++it) {
- if (FileNum != it->getFileNum()) {
- FileNum = it->getFileNum();
- MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
- MCOS->EmitULEB128IntValue(FileNum);
- }
- if (Column != it->getColumn()) {
- Column = it->getColumn();
- MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
- MCOS->EmitULEB128IntValue(Column);
- }
- if (Isa != it->getIsa()) {
- Isa = it->getIsa();
- MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
- MCOS->EmitULEB128IntValue(Isa);
- }
- if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
- Flags = it->getFlags();
- MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
- }
- if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
- MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
- if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
- MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
- if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
- MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
- int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
- MCSymbol *Label = it->getLabel();
- // At this point we want to emit/create the sequence to encode the delta in
- // line numbers and the increment of the address from the previous Label
- // and the current Label.
- const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
- MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
- asmInfo.getPointerSize());
- LastLine = it->getLine();
- LastLabel = Label;
- }
- // Emit a DW_LNE_end_sequence for the end of the section.
- // Using the pointer Section create a temporary label at the end of the
- // section and use that and the LastLabel to compute the address delta
- // and use INT64_MAX as the line delta which is the signal that this is
- // actually a DW_LNE_end_sequence.
- // Switch to the section to be able to create a symbol at its end.
- MCOS->SwitchSection(Section);
- MCContext &context = MCOS->getContext();
- // Create a symbol at the end of the section.
- MCSymbol *SectionEnd = context.CreateTempSymbol();
- // Set the value of the symbol, as we are at the end of the section.
- MCOS->EmitLabel(SectionEnd);
- // Switch back the dwarf line section.
- MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
- const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
- MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
- asmInfo.getPointerSize());
- }
- //
- // This emits the Dwarf file and the line tables.
- //
- const MCSymbol *MCDwarfFileTable::Emit(MCStreamer *MCOS) {
- MCContext &context = MCOS->getContext();
- // Switch to the section where the table will be emitted into.
- MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
- const DenseMap<unsigned, MCSymbol *> &MCLineTableSymbols =
- MCOS->getContext().getMCLineTableSymbols();
- // CUID and MCLineTableSymbols are set in DwarfDebug, when DwarfDebug does
- // not exist, CUID will be 0 and MCLineTableSymbols will be empty.
- // Handle Compile Unit 0, the line table start symbol is the section symbol.
- const MCSymbol *LineStartSym = EmitCU(MCOS, 0);
- // Handle the rest of the Compile Units.
- for (unsigned Is = 1, Ie = MCLineTableSymbols.size(); Is < Ie; Is++)
- EmitCU(MCOS, Is);
- // Now delete the MCLineSections that were created in MCLineEntry::Make()
- // and used to emit the line table.
- const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
- MCOS->getContext().getMCLineSections();
- for (DenseMap<const MCSection *, MCLineSection *>::const_iterator it =
- MCLineSections.begin(), ie = MCLineSections.end(); it != ie;
- ++it)
- delete it->second;
- return LineStartSym;
- }
- const MCSymbol *MCDwarfFileTable::EmitCU(MCStreamer *MCOS, unsigned CUID) {
- MCContext &context = MCOS->getContext();
- // Create a symbol at the beginning of the line table.
- MCSymbol *LineStartSym = MCOS->getContext().getMCLineTableSymbol(CUID);
- if (!LineStartSym)
- LineStartSym = context.CreateTempSymbol();
- // Set the value of the symbol, as we are at the start of the line table.
- MCOS->EmitLabel(LineStartSym);
- // Create a symbol for the end of the section (to be set when we get there).
- MCSymbol *LineEndSym = context.CreateTempSymbol();
- // The first 4 bytes is the total length of the information for this
- // compilation unit (not including these 4 bytes for the length).
- MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym,4),
- 4);
- // Next 2 bytes is the Version, which is Dwarf 2.
- MCOS->EmitIntValue(2, 2);
- // Create a symbol for the end of the prologue (to be set when we get there).
- MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
- // Length of the prologue, is the next 4 bytes. Which is the start of the
- // section to the end of the prologue. Not including the 4 bytes for the
- // total length, the 2 bytes for the version, and these 4 bytes for the
- // length of the prologue.
- MCOS->EmitAbsValue(MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym,
- (4 + 2 + 4)), 4, 0);
- // Parameters of the state machine, are next.
- MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
- MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
- MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
- MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
- MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
- // Standard opcode lengths
- MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
- MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
- MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
- MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
- MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
- MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
- MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
- MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
- MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
- MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
- MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
- MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
- // Put out the directory and file tables.
- // First the directory table.
- const SmallVectorImpl<StringRef> &MCDwarfDirs =
- context.getMCDwarfDirs(CUID);
- for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
- MCOS->EmitBytes(MCDwarfDirs[i]); // the DirectoryName
- MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
- }
- MCOS->EmitIntValue(0, 1); // Terminate the directory list
- // Second the file table.
- const SmallVectorImpl<MCDwarfFile *> &MCDwarfFiles =
- MCOS->getContext().getMCDwarfFiles(CUID);
- for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
- MCOS->EmitBytes(MCDwarfFiles[i]->getName()); // FileName
- MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
- // the Directory num
- MCOS->EmitULEB128IntValue(MCDwarfFiles[i]->getDirIndex());
- MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
- MCOS->EmitIntValue(0, 1); // filesize (always 0)
- }
- MCOS->EmitIntValue(0, 1); // Terminate the file list
- // This is the end of the prologue, so set the value of the symbol at the
- // end of the prologue (that was used in a previous expression).
- MCOS->EmitLabel(ProEndSym);
- // Put out the line tables.
- const DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
- MCOS->getContext().getMCLineSections();
- const std::vector<const MCSection *> &MCLineSectionOrder =
- MCOS->getContext().getMCLineSectionOrder();
- for (std::vector<const MCSection*>::const_iterator it =
- MCLineSectionOrder.begin(), ie = MCLineSectionOrder.end(); it != ie;
- ++it) {
- const MCSection *Sec = *it;
- const MCLineSection *Line = MCLineSections.lookup(Sec);
- EmitDwarfLineTable(MCOS, Sec, Line, CUID);
- }
- if (MCOS->getContext().getAsmInfo().getLinkerRequiresNonEmptyDwarfLines()
- && MCLineSectionOrder.begin() == MCLineSectionOrder.end()) {
- // The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
- // it requires:
- // total_length >= prologue_length + 10
- // We are 4 bytes short, since we have total_length = 51 and
- // prologue_length = 45
- // The regular end_sequence should be sufficient.
- MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
- }
- // This is the end of the section, so set the value of the symbol at the end
- // of this section (that was used in a previous expression).
- MCOS->EmitLabel(LineEndSym);
- return LineStartSym;
- }
- /// Utility function to write the encoding to an object writer.
- void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
- uint64_t AddrDelta) {
- SmallString<256> Tmp;
- raw_svector_ostream OS(Tmp);
- MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
- OW->WriteBytes(OS.str());
- }
- /// Utility function to emit the encoding to a streamer.
- void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
- uint64_t AddrDelta) {
- SmallString<256> Tmp;
- raw_svector_ostream OS(Tmp);
- MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
- MCOS->EmitBytes(OS.str());
- }
- /// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
- void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
- raw_ostream &OS) {
- uint64_t Temp, Opcode;
- bool NeedCopy = false;
- // Scale the address delta by the minimum instruction length.
- AddrDelta = ScaleAddrDelta(AddrDelta);
- // A LineDelta of INT64_MAX is a signal that this is actually a
- // DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
- // end_sequence to emit the matrix entry.
- if (LineDelta == INT64_MAX) {
- if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
- OS << char(dwarf::DW_LNS_const_add_pc);
- else {
- OS << char(dwarf::DW_LNS_advance_pc);
- encodeULEB128(AddrDelta, OS);
- }
- OS << char(dwarf::DW_LNS_extended_op);
- OS << char(1);
- OS << char(dwarf::DW_LNE_end_sequence);
- return;
- }
- // Bias the line delta by the base.
- Temp = LineDelta - DWARF2_LINE_BASE;
- // If the line increment is out of range of a special opcode, we must encode
- // it with DW_LNS_advance_line.
- if (Temp >= DWARF2_LINE_RANGE) {
- OS << char(dwarf::DW_LNS_advance_line);
- encodeSLEB128(LineDelta, OS);
- LineDelta = 0;
- Temp = 0 - DWARF2_LINE_BASE;
- NeedCopy = true;
- }
- // Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
- if (LineDelta == 0 && AddrDelta == 0) {
- OS << char(dwarf::DW_LNS_copy);
- return;
- }
- // Bias the opcode by the special opcode base.
- Temp += DWARF2_LINE_OPCODE_BASE;
- // Avoid overflow when addr_delta is large.
- if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
- // Try using a special opcode.
- Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
- if (Opcode <= 255) {
- OS << char(Opcode);
- return;
- }
- // Try using DW_LNS_const_add_pc followed by special op.
- Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
- if (Opcode <= 255) {
- OS << char(dwarf::DW_LNS_const_add_pc);
- OS << char(Opcode);
- return;
- }
- }
- // Otherwise use DW_LNS_advance_pc.
- OS << char(dwarf::DW_LNS_advance_pc);
- encodeULEB128(AddrDelta, OS);
- if (NeedCopy)
- OS << char(dwarf::DW_LNS_copy);
- else
- OS << char(Temp);
- }
- void MCDwarfFile::print(raw_ostream &OS) const {
- OS << '"' << getName() << '"';
- }
- #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
- void MCDwarfFile::dump() const {
- print(dbgs());
- }
- #endif
- // Utility function to write a tuple for .debug_abbrev.
- static void EmitAbbrev(MCStreamer *MCOS, uint64_t Name, uint64_t Form) {
- MCOS->EmitULEB128IntValue(Name);
- MCOS->EmitULEB128IntValue(Form);
- }
- // When generating dwarf for assembly source files this emits
- // the data for .debug_abbrev section which contains three DIEs.
- static void EmitGenDwarfAbbrev(MCStreamer *MCOS) {
- MCContext &context = MCOS->getContext();
- MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
- // DW_TAG_compile_unit DIE abbrev (1).
- MCOS->EmitULEB128IntValue(1);
- MCOS->EmitULEB128IntValue(dwarf::DW_TAG_compile_unit);
- MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
- EmitAbbrev(MCOS, dwarf::DW_AT_stmt_list, dwarf::DW_FORM_data4);
- EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
- EmitAbbrev(MCOS, dwarf::DW_AT_high_pc, dwarf::DW_FORM_addr);
- EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
- EmitAbbrev(MCOS, dwarf::DW_AT_comp_dir, dwarf::DW_FORM_string);
- StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
- if (!DwarfDebugFlags.empty())
- EmitAbbrev(MCOS, dwarf::DW_AT_APPLE_flags, dwarf::DW_FORM_string);
- EmitAbbrev(MCOS, dwarf::DW_AT_producer, dwarf::DW_FORM_string);
- EmitAbbrev(MCOS, dwarf::DW_AT_language, dwarf::DW_FORM_data2);
- EmitAbbrev(MCOS, 0, 0);
- // DW_TAG_label DIE abbrev (2).
- MCOS->EmitULEB128IntValue(2);
- MCOS->EmitULEB128IntValue(dwarf::DW_TAG_label);
- MCOS->EmitIntValue(dwarf::DW_CHILDREN_yes, 1);
- EmitAbbrev(MCOS, dwarf::DW_AT_name, dwarf::DW_FORM_string);
- EmitAbbrev(MCOS, dwarf::DW_AT_decl_file, dwarf::DW_FORM_data4);
- EmitAbbrev(MCOS, dwarf::DW_AT_decl_line, dwarf::DW_FORM_data4);
- EmitAbbrev(MCOS, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr);
- EmitAbbrev(MCOS, dwarf::DW_AT_prototyped, dwarf::DW_FORM_flag);
- EmitAbbrev(MCOS, 0, 0);
- // DW_TAG_unspecified_parameters DIE abbrev (3).
- MCOS->EmitULEB128IntValue(3);
- MCOS->EmitULEB128IntValue(dwarf::DW_TAG_unspecified_parameters);
- MCOS->EmitIntValue(dwarf::DW_CHILDREN_no, 1);
- EmitAbbrev(MCOS, 0, 0);
- // Terminate the abbreviations for this compilation unit.
- MCOS->EmitIntValue(0, 1);
- }
- // When generating dwarf for assembly source files this emits the data for
- // .debug_aranges section. Which contains a header and a table of pairs of
- // PointerSize'ed values for the address and size of section(s) with line table
- // entries (just the default .text in our case) and a terminating pair of zeros.
- static void EmitGenDwarfAranges(MCStreamer *MCOS,
- const MCSymbol *InfoSectionSymbol) {
- MCContext &context = MCOS->getContext();
- // Create a symbol at the end of the section that we are creating the dwarf
- // debugging info to use later in here as part of the expression to calculate
- // the size of the section for the table.
- MCOS->SwitchSection(context.getGenDwarfSection());
- MCSymbol *SectionEndSym = context.CreateTempSymbol();
- MCOS->EmitLabel(SectionEndSym);
- context.setGenDwarfSectionEndSym(SectionEndSym);
- MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
- // This will be the length of the .debug_aranges section, first account for
- // the size of each item in the header (see below where we emit these items).
- int Length = 4 + 2 + 4 + 1 + 1;
- // Figure the padding after the header before the table of address and size
- // pairs who's values are PointerSize'ed.
- const MCAsmInfo &asmInfo = context.getAsmInfo();
- int AddrSize = asmInfo.getPointerSize();
- int Pad = 2 * AddrSize - (Length & (2 * AddrSize - 1));
- if (Pad == 2 * AddrSize)
- Pad = 0;
- Length += Pad;
- // Add the size of the pair of PointerSize'ed values for the address and size
- // of the one default .text section we have in the table.
- Length += 2 * AddrSize;
- // And the pair of terminating zeros.
- Length += 2 * AddrSize;
- // Emit the header for this section.
- // The 4 byte length not including the 4 byte value for the length.
- MCOS->EmitIntValue(Length - 4, 4);
- // The 2 byte version, which is 2.
- MCOS->EmitIntValue(2, 2);
- // The 4 byte offset to the compile unit in the .debug_info from the start
- // of the .debug_info.
- if (InfoSectionSymbol)
- MCOS->EmitSymbolValue(InfoSectionSymbol, 4);
- else
- MCOS->EmitIntValue(0, 4);
- // The 1 byte size of an address.
- MCOS->EmitIntValue(AddrSize, 1);
- // The 1 byte size of a segment descriptor, we use a value of zero.
- MCOS->EmitIntValue(0, 1);
- // Align the header with the padding if needed, before we put out the table.
- for(int i = 0; i < Pad; i++)
- MCOS->EmitIntValue(0, 1);
- // Now emit the table of pairs of PointerSize'ed values for the section(s)
- // address and size, in our case just the one default .text section.
- const MCExpr *Addr = MCSymbolRefExpr::Create(
- context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
- const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
- *context.getGenDwarfSectionStartSym(), *SectionEndSym, 0);
- MCOS->EmitAbsValue(Addr, AddrSize);
- MCOS->EmitAbsValue(Size, AddrSize);
- // And finally the pair of terminating zeros.
- MCOS->EmitIntValue(0, AddrSize);
- MCOS->EmitIntValue(0, AddrSize);
- }
- // When generating dwarf for assembly source files this emits the data for
- // .debug_info section which contains three parts. The header, the compile_unit
- // DIE and a list of label DIEs.
- static void EmitGenDwarfInfo(MCStreamer *MCOS,
- const MCSymbol *AbbrevSectionSymbol,
- const MCSymbol *LineSectionSymbol) {
- MCContext &context = MCOS->getContext();
- MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
- // Create a symbol at the start and end of this section used in here for the
- // expression to calculate the length in the header.
- MCSymbol *InfoStart = context.CreateTempSymbol();
- MCOS->EmitLabel(InfoStart);
- MCSymbol *InfoEnd = context.CreateTempSymbol();
- // First part: the header.
- // The 4 byte total length of the information for this compilation unit, not
- // including these 4 bytes.
- const MCExpr *Length = MakeStartMinusEndExpr(*MCOS, *InfoStart, *InfoEnd, 4);
- MCOS->EmitAbsValue(Length, 4);
- // The 2 byte DWARF version, which is 2.
- MCOS->EmitIntValue(2, 2);
- // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
- // it is at the start of that section so this is zero.
- if (AbbrevSectionSymbol) {
- MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4);
- } else {
- MCOS->EmitIntValue(0, 4);
- }
- const MCAsmInfo &asmInfo = context.getAsmInfo();
- int AddrSize = asmInfo.getPointerSize();
- // The 1 byte size of an address.
- MCOS->EmitIntValue(AddrSize, 1);
- // Second part: the compile_unit DIE.
- // The DW_TAG_compile_unit DIE abbrev (1).
- MCOS->EmitULEB128IntValue(1);
- // DW_AT_stmt_list, a 4 byte offset from the start of the .debug_line section,
- // which is at the start of that section so this is zero.
- if (LineSectionSymbol) {
- MCOS->EmitSymbolValue(LineSectionSymbol, 4);
- } else {
- MCOS->EmitIntValue(0, 4);
- }
- // AT_low_pc, the first address of the default .text section.
- const MCExpr *Start = MCSymbolRefExpr::Create(
- context.getGenDwarfSectionStartSym(), MCSymbolRefExpr::VK_None, context);
- MCOS->EmitAbsValue(Start, AddrSize);
- // AT_high_pc, the last address of the default .text section.
- const MCExpr *End = MCSymbolRefExpr::Create(
- context.getGenDwarfSectionEndSym(), MCSymbolRefExpr::VK_None, context);
- MCOS->EmitAbsValue(End, AddrSize);
- // AT_name, the name of the source file. Reconstruct from the first directory
- // and file table entries.
- const SmallVectorImpl<StringRef> &MCDwarfDirs =
- context.getMCDwarfDirs();
- if (MCDwarfDirs.size() > 0) {
- MCOS->EmitBytes(MCDwarfDirs[0]);
- MCOS->EmitBytes("/");
- }
- const SmallVectorImpl<MCDwarfFile *> &MCDwarfFiles =
- MCOS->getContext().getMCDwarfFiles();
- MCOS->EmitBytes(MCDwarfFiles[1]->getName());
- MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
- // AT_comp_dir, the working directory the assembly was done in.
- MCOS->EmitBytes(context.getCompilationDir());
- MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
- // AT_APPLE_flags, the command line arguments of the assembler tool.
- StringRef DwarfDebugFlags = context.getDwarfDebugFlags();
- if (!DwarfDebugFlags.empty()){
- MCOS->EmitBytes(DwarfDebugFlags);
- MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
- }
- // AT_producer, the version of the assembler tool.
- StringRef DwarfDebugProducer = context.getDwarfDebugProducer();
- if (!DwarfDebugProducer.empty()){
- MCOS->EmitBytes(DwarfDebugProducer);
- }
- else {
- MCOS->EmitBytes(StringRef("llvm-mc (based on LLVM "));
- MCOS->EmitBytes(StringRef(PACKAGE_VERSION));
- MCOS->EmitBytes(StringRef(")"));
- }
- MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
- // AT_language, a 4 byte value. We use DW_LANG_Mips_Assembler as the dwarf2
- // draft has no standard code for assembler.
- MCOS->EmitIntValue(dwarf::DW_LANG_Mips_Assembler, 2);
- // Third part: the list of label DIEs.
- // Loop on saved info for dwarf labels and create the DIEs for them.
- const std::vector<const MCGenDwarfLabelEntry *> &Entries =
- MCOS->getContext().getMCGenDwarfLabelEntries();
- for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
- Entries.begin(), ie = Entries.end(); it != ie;
- ++it) {
- const MCGenDwarfLabelEntry *Entry = *it;
- // The DW_TAG_label DIE abbrev (2).
- MCOS->EmitULEB128IntValue(2);
- // AT_name, of the label without any leading underbar.
- MCOS->EmitBytes(Entry->getName());
- MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
- // AT_decl_file, index into the file table.
- MCOS->EmitIntValue(Entry->getFileNumber(), 4);
- // AT_decl_line, source line number.
- MCOS->EmitIntValue(Entry->getLineNumber(), 4);
- // AT_low_pc, start address of the label.
- const MCExpr *AT_low_pc = MCSymbolRefExpr::Create(Entry->getLabel(),
- MCSymbolRefExpr::VK_None, context);
- MCOS->EmitAbsValue(AT_low_pc, AddrSize);
- // DW_AT_prototyped, a one byte flag value of 0 saying we have no prototype.
- MCOS->EmitIntValue(0, 1);
- // The DW_TAG_unspecified_parameters DIE abbrev (3).
- MCOS->EmitULEB128IntValue(3);
- // Add the NULL DIE terminating the DW_TAG_unspecified_parameters DIE's.
- MCOS->EmitIntValue(0, 1);
- }
- // Deallocate the MCGenDwarfLabelEntry classes that saved away the info
- // for the dwarf labels.
- for (std::vector<const MCGenDwarfLabelEntry *>::const_iterator it =
- Entries.begin(), ie = Entries.end(); it != ie;
- ++it) {
- const MCGenDwarfLabelEntry *Entry = *it;
- delete Entry;
- }
- // Add the NULL DIE terminating the Compile Unit DIE's.
- MCOS->EmitIntValue(0, 1);
- // Now set the value of the symbol at the end of the info section.
- MCOS->EmitLabel(InfoEnd);
- }
- //
- // When generating dwarf for assembly source files this emits the Dwarf
- // sections.
- //
- void MCGenDwarfInfo::Emit(MCStreamer *MCOS, const MCSymbol *LineSectionSymbol) {
- // Create the dwarf sections in this order (.debug_line already created).
- MCContext &context = MCOS->getContext();
- const MCAsmInfo &AsmInfo = context.getAsmInfo();
- bool CreateDwarfSectionSymbols =
- AsmInfo.doesDwarfUseRelocationsAcrossSections();
- if (!CreateDwarfSectionSymbols)
- LineSectionSymbol = NULL;
- MCSymbol *AbbrevSectionSymbol = NULL;
- MCSymbol *InfoSectionSymbol = NULL;
- MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfInfoSection());
- if (CreateDwarfSectionSymbols) {
- InfoSectionSymbol = context.CreateTempSymbol();
- MCOS->EmitLabel(InfoSectionSymbol);
- }
- MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfAbbrevSection());
- if (CreateDwarfSectionSymbols) {
- AbbrevSectionSymbol = context.CreateTempSymbol();
- MCOS->EmitLabel(AbbrevSectionSymbol);
- }
- MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
- // If there are no line table entries then do not emit any section contents.
- if (context.getMCLineSections().empty())
- return;
- // Output the data for .debug_aranges section.
- EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
- // Output the data for .debug_abbrev section.
- EmitGenDwarfAbbrev(MCOS);
- // Output the data for .debug_info section.
- EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol);
- }
- //
- // When generating dwarf for assembly source files this is called when symbol
- // for a label is created. If this symbol is not a temporary and is in the
- // section that dwarf is being generated for, save the needed info to create
- // a dwarf label.
- //
- void MCGenDwarfLabelEntry::Make(MCSymbol *Symbol, MCStreamer *MCOS,
- SourceMgr &SrcMgr, SMLoc &Loc) {
- // We won't create dwarf labels for temporary symbols or symbols not in
- // the default text.
- if (Symbol->isTemporary())
- return;
- MCContext &context = MCOS->getContext();
- if (context.getGenDwarfSection() != MCOS->getCurrentSection())
- return;
- // The dwarf label's name does not have the symbol name's leading
- // underbar if any.
- StringRef Name = Symbol->getName();
- if (Name.startswith("_"))
- Name = Name.substr(1, Name.size()-1);
- // Get the dwarf file number to be used for the dwarf label.
- unsigned FileNumber = context.getGenDwarfFileNumber();
- // Finding the line number is the expensive part which is why we just don't
- // pass it in as for some symbols we won't create a dwarf label.
- int CurBuffer = SrcMgr.FindBufferContainingLoc(Loc);
- unsigned LineNumber = SrcMgr.FindLineNumber(Loc, CurBuffer);
- // We create a temporary symbol for use for the AT_high_pc and AT_low_pc
- // values so that they don't have things like an ARM thumb bit from the
- // original symbol. So when used they won't get a low bit set after
- // relocation.
- MCSymbol *Label = context.CreateTempSymbol();
- MCOS->EmitLabel(Label);
- // Create and entry for the info and add it to the other entries.
- MCGenDwarfLabelEntry *Entry =
- new MCGenDwarfLabelEntry(Name, FileNumber, LineNumber, Label);
- MCOS->getContext().addMCGenDwarfLabelEntry(Entry);
- }
- static int getDataAlignmentFactor(MCStreamer &streamer) {
- MCContext &context = streamer.getContext();
- const MCAsmInfo &asmInfo = context.getAsmInfo();
- int size = asmInfo.getCalleeSaveStackSlotSize();
- if (asmInfo.isStackGrowthDirectionUp())
- return size;
- else
- return -size;
- }
- static unsigned getSizeForEncoding(MCStreamer &streamer,
- unsigned symbolEncoding) {
- MCContext &context = streamer.getContext();
- unsigned format = symbolEncoding & 0x0f;
- switch (format) {
- default: llvm_unreachable("Unknown Encoding");
- case dwarf::DW_EH_PE_absptr:
- case dwarf::DW_EH_PE_signed:
- return context.getAsmInfo().getPointerSize();
- case dwarf::DW_EH_PE_udata2:
- case dwarf::DW_EH_PE_sdata2:
- return 2;
- case dwarf::DW_EH_PE_udata4:
- case dwarf::DW_EH_PE_sdata4:
- return 4;
- case dwarf::DW_EH_PE_udata8:
- case dwarf::DW_EH_PE_sdata8:
- return 8;
- }
- }
- static void EmitSymbol(MCStreamer &streamer, const MCSymbol &symbol,
- unsigned symbolEncoding, const char *comment = 0) {
- MCContext &context = streamer.getContext();
- const MCAsmInfo &asmInfo = context.getAsmInfo();
- const MCExpr *v = asmInfo.getExprForFDESymbol(&symbol,
- symbolEncoding,
- streamer);
- unsigned size = getSizeForEncoding(streamer, symbolEncoding);
- if (streamer.isVerboseAsm() && comment) streamer.AddComment(comment);
- streamer.EmitAbsValue(v, size);
- }
- static void EmitPersonality(MCStreamer &streamer, const MCSymbol &symbol,
- unsigned symbolEncoding) {
- MCContext &context = streamer.getContext();
- const MCAsmInfo &asmInfo = context.getAsmInfo();
- const MCExpr *v = asmInfo.getExprForPersonalitySymbol(&symbol,
- symbolEncoding,
- streamer);
- unsigned size = getSizeForEncoding(streamer, symbolEncoding);
- streamer.EmitValue(v, size);
- }
- static const MachineLocation TranslateMachineLocation(
- const MCRegisterInfo &MRI,
- const MachineLocation &Loc) {
- unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
- MachineLocation::VirtualFP :
- unsigned(MRI.getDwarfRegNum(Loc.getReg(), true));
- const MachineLocation &NewLoc = Loc.isReg() ?
- MachineLocation(Reg) : MachineLocation(Reg, Loc.getOffset());
- return NewLoc;
- }
- namespace {
- class FrameEmitterImpl {
- int CFAOffset;
- int CIENum;
- bool UsingCFI;
- bool IsEH;
- const MCSymbol *SectionStart;
- public:
- FrameEmitterImpl(bool usingCFI, bool isEH)
- : CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
- SectionStart(0) {}
- void setSectionStart(const MCSymbol *Label) { SectionStart = Label; }
- /// EmitCompactUnwind - Emit the unwind information in a compact way. If
- /// we're successful, return 'true'. Otherwise, return 'false' and it will
- /// emit the normal CIE and FDE.
- bool EmitCompactUnwind(MCStreamer &streamer,
- const MCDwarfFrameInfo &frame);
- const MCSymbol &EmitCIE(MCStreamer &streamer,
- const MCSymbol *personality,
- unsigned personalityEncoding,
- const MCSymbol *lsda,
- bool IsSignalFrame,
- unsigned lsdaEncoding);
- MCSymbol *EmitFDE(MCStreamer &streamer,
- const MCSymbol &cieStart,
- const MCDwarfFrameInfo &frame);
- void EmitCFIInstructions(MCStreamer &streamer,
- const std::vector<MCCFIInstruction> &Instrs,
- MCSymbol *BaseLabel);
- void EmitCFIInstruction(MCStreamer &Streamer,
- const MCCFIInstruction &Instr);
- };
- } // end anonymous namespace
- static void EmitEncodingByte(MCStreamer &Streamer, unsigned Encoding,
- StringRef Prefix) {
- if (Streamer.isVerboseAsm()) {
- const char *EncStr;
- switch (Encoding) {
- default: EncStr = "<unknown encoding>"; break;
- case dwarf::DW_EH_PE_absptr: EncStr = "absptr"; break;
- case dwarf::DW_EH_PE_omit: EncStr = "omit"; break;
- case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel"; break;
- case dwarf::DW_EH_PE_udata4: EncStr = "udata4"; break;
- case dwarf::DW_EH_PE_udata8: EncStr = "udata8"; break;
- case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4"; break;
- case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8"; break;
- case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
- EncStr = "pcrel udata4";
- break;
- case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
- EncStr = "pcrel sdata4";
- break;
- case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
- EncStr = "pcrel udata8";
- break;
- case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
- EncStr = "screl sdata8";
- break;
- case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
- EncStr = "indirect pcrel udata4";
- break;
- case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
- EncStr = "indirect pcrel sdata4";
- break;
- case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
- EncStr = "indirect pcrel udata8";
- break;
- case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
- EncStr = "indirect pcrel sdata8";
- break;
- }
- Streamer.AddComment(Twine(Prefix) + " = " + EncStr);
- }
- Streamer.EmitIntValue(Encoding, 1);
- }
- void FrameEmitterImpl::EmitCFIInstruction(MCStreamer &Streamer,
- const MCCFIInstruction &Instr) {
- int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
- bool VerboseAsm = Streamer.isVerboseAsm();
- switch (Instr.getOperation()) {
- case MCCFIInstruction::OpRegister: {
- unsigned Reg1 = Instr.getRegister();
- unsigned Reg2 = Instr.getRegister2();
- if (VerboseAsm) {
- Streamer.AddComment("DW_CFA_register");
- Streamer.AddComment(Twine("Reg1 ") + Twine(Reg1));
- Streamer.AddComment(Twine("Reg2 ") + Twine(Reg2));
- }
- Streamer.EmitIntValue(dwarf::DW_CFA_register, 1);
- Streamer.EmitULEB128IntValue(Reg1);
- Streamer.EmitULEB128IntValue(Reg2);
- return;
- }
- case MCCFIInstruction::OpUndefined: {
- unsigned Reg = Instr.getRegister();
- if (VerboseAsm) {
- Streamer.AddComment("DW_CFA_undefined");
- Streamer.AddComment(Twine("Reg ") + Twine(Reg));
- }
- Streamer.EmitIntValue(dwarf::DW_CFA_undefined, 1);
- Streamer.EmitULEB128IntValue(Reg);
- return;
- }
- case MCCFIInstruction::OpAdjustCfaOffset:
- case MCCFIInstruction::OpDefCfaOffset: {
- const bool IsRelative =
- Instr.getOperation() == MCCFIInstruction::OpAdjustCfaOffset;
- if (VerboseAsm)
- Streamer.AddComment("DW_CFA_def_cfa_offset");
- Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
- if (IsRelative)
- CFAOffset += Instr.getOffset();
- else
- CFAOffset = -Instr.getOffset();
- if (VerboseAsm)
- Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
- Streamer.EmitULEB128IntValue(CFAOffset);
- return;
- }
- case MCCFIInstruction::OpDefCfa: {
- if (VerboseAsm)
- Streamer.AddComment("DW_CFA_def_cfa");
- Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
- if (VerboseAsm)
- Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
- Streamer.EmitULEB128IntValue(Instr.getRegister());
- CFAOffset = -Instr.getOffset();
- if (VerboseAsm)
- Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
- Streamer.EmitULEB128IntValue(CFAOffset);
- return;
- }
- case MCCFIInstruction::OpDefCfaRegister: {
- if (VerboseAsm)
- Streamer.AddComment("DW_CFA_def_cfa_register");
- Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
- if (VerboseAsm)
- Streamer.AddComment(Twine("Reg ") + Twine(Instr.getRegister()));
- Streamer.EmitULEB128IntValue(Instr.getRegister());
- return;
- }
- case MCCFIInstruction::OpOffset:
- case MCCFIInstruction::OpRelOffset: {
- const bool IsRelative =
- Instr.getOperation() == MCCFIInstruction::OpRelOffset;
- unsigned Reg = Instr.getRegister();
- int Offset = Instr.getOffset();
- if (IsRelative)
- Offset -= CFAOffset;
- Offset = Offset / dataAlignmentFactor;
- if (Offset < 0) {
- if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended_sf");
- Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
- if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
- Streamer.EmitULEB128IntValue(Reg);
- if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
- Streamer.EmitSLEB128IntValue(Offset);
- } else if (Reg < 64) {
- if (VerboseAsm) Streamer.AddComment(Twine("DW_CFA_offset + Reg(") +
- Twine(Reg) + ")");
- Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
- if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
- Streamer.EmitULEB128IntValue(Offset);
- } else {
- if (VerboseAsm) Streamer.AddComment("DW_CFA_offset_extended");
- Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
- if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
- Streamer.EmitULEB128IntValue(Reg);
- if (VerboseAsm) Streamer.AddComment(Twine("Offset ") + Twine(Offset));
- Streamer.EmitULEB128IntValue(Offset);
- }
- return;
- }
- case MCCFIInstruction::OpRememberState:
- if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
- Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
- return;
- case MCCFIInstruction::OpRestoreState:
- if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
- Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
- return;
- case MCCFIInstruction::OpSameValue: {
- unsigned Reg = Instr.getRegister();
- if (VerboseAsm) Streamer.AddComment("DW_CFA_same_value");
- Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
- if (VerboseAsm) Streamer.AddComment(Twine("Reg ") + Twine(Reg));
- Streamer.EmitULEB128IntValue(Reg);
- return;
- }
- case MCCFIInstruction::OpRestore: {
- unsigned Reg = Instr.getRegister();
- if (VerboseAsm) {
- Streamer.AddComment("DW_CFA_restore");
- Streamer.AddComment(Twine("Reg ") + Twine(Reg));
- }
- Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
- return;
- }
- case MCCFIInstruction::OpEscape:
- if (VerboseAsm) Streamer.AddComment("Escape bytes");
- Streamer.EmitBytes(Instr.getValues());
- return;
- }
- llvm_unreachable("Unhandled case in switch");
- }
- /// EmitFrameMoves - Emit frame instructions to describe the layout of the
- /// frame.
- void FrameEmitterImpl::EmitCFIInstructions(MCStreamer &streamer,
- const std::vector<MCCFIInstruction> &Instrs,
- MCSymbol *BaseLabel) {
- for (unsigned i = 0, N = Instrs.size(); i < N; ++i) {
- const MCCFIInstruction &Instr = Instrs[i];
- MCSymbol *Label = Instr.getLabel();
- // Throw out move if the label is invalid.
- if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
- // Advance row if new location.
- if (BaseLabel && Label) {
- MCSymbol *ThisSym = Label;
- if (ThisSym != BaseLabel) {
- if (streamer.isVerboseAsm()) streamer.AddComment("DW_CFA_advance_loc4");
- streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
- BaseLabel = ThisSym;
- }
- }
- EmitCFIInstruction(streamer, Instr);
- }
- }
- /// EmitCompactUnwind - Emit the unwind information in a compact way. If we're
- /// successful, return 'true'. Otherwise, return 'false' and it will emit the
- /// normal CIE and FDE.
- bool FrameEmitterImpl::EmitCompactUnwind(MCStreamer &Streamer,
- const MCDwarfFrameInfo &Frame) {
- MCContext &Context = Streamer.getContext();
- const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
- bool VerboseAsm = Streamer.isVerboseAsm();
- // range-start range-length compact-unwind-enc personality-func lsda
- // _foo LfooEnd-_foo 0x00000023 0 0
- // _bar LbarEnd-_bar 0x00000025 __gxx_personality except_tab1
- //
- // .section __LD,__compact_unwind,regular,debug
- //
- // # compact unwind for _foo
- // .quad _foo
- // .set L1,LfooEnd-_foo
- // .long L1
- // .long 0x01010001
- // .quad 0
- // .quad 0
- //
- // # compact unwind for _bar
- // .quad _bar
- // .set L2,LbarEnd-_bar
- // .long L2
- // .long 0x01020011
- // .quad __gxx_personality
- // .quad except_tab1
- uint32_t Encoding = Frame.CompactUnwindEncoding;
- bool DwarfEHFrameOnly = (Encoding == MOFI->getCompactUnwindDwarfEHFrameOnly());
- // The encoding needs to know we have an LSDA.
- if (!DwarfEHFrameOnly && Frame.Lsda)
- Encoding |= 0x40000000;
- Streamer.SwitchSection(MOFI->getCompactUnwindSection());
- // Range Start
- unsigned FDEEncoding = MOFI->getFDEEncoding(UsingCFI);
- unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
- if (VerboseAsm) Streamer.AddComment("Range Start");
- Streamer.EmitSymbolValue(Frame.Function, Size);
- // Range Length
- const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
- *Frame.End, 0);
- if (VerboseAsm) Streamer.AddComment("Range Length");
- Streamer.EmitAbsValue(Range, 4);
- // Compact Encoding
- Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
- if (VerboseAsm) Streamer.AddComment("Compact Unwind Encoding: 0x" +
- Twine::utohexstr(Encoding));
- Streamer.EmitIntValue(Encoding, Size);
- // Personality Function
- Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
- if (VerboseAsm) Streamer.AddComment("Personality Function");
- if (!DwarfEHFrameOnly && Frame.Personality)
- Streamer.EmitSymbolValue(Frame.Personality, Size);
- else
- Streamer.EmitIntValue(0, Size); // No personality fn
- // LSDA
- Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
- if (VerboseAsm) Streamer.AddComment("LSDA");
- if (!DwarfEHFrameOnly && Frame.Lsda)
- Streamer.EmitSymbolValue(Frame.Lsda, Size);
- else
- Streamer.EmitIntValue(0, Size); // No LSDA
- return true;
- }
- const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
- const MCSymbol *personality,
- unsigned personalityEncoding,
- const MCSymbol *lsda,
- bool IsSignalFrame,
- unsigned lsdaEncoding) {
- MCContext &context = streamer.getContext();
- const MCRegisterInfo &MRI = context.getRegisterInfo();
- const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
- bool verboseAsm = streamer.isVerboseAsm();
- MCSymbol *sectionStart;
- if (MOFI->isFunctionEHFrameSymbolPrivate() || !IsEH)
- sectionStart = context.CreateTempSymbol();
- else
- sectionStart = context.GetOrCreateSymbol(Twine("EH_frame") + Twine(CIENum));
- streamer.EmitLabel(sectionStart);
- CIENum++;
- MCSymbol *sectionEnd = context.CreateTempSymbol();
- // Length
- const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
- *sectionEnd, 4);
- if (verboseAsm) streamer.AddComment("CIE Length");
- streamer.EmitAbsValue(Length, 4);
- // CIE ID
- unsigned CIE_ID = IsEH ? 0 : -1;
- if (verboseAsm) streamer.AddComment("CIE ID Tag");
- streamer.EmitIntValue(CIE_ID, 4);
- // Version
- if (verboseAsm) streamer.AddComment("DW_CIE_VERSION");
- streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
- // Augmentation String
- SmallString<8> Augmentation;
- if (IsEH) {
- if (verboseAsm) streamer.AddComment("CIE Augmentation");
- Augmentation += "z";
- if (personality)
- Augmentation += "P";
- if (lsda)
- Augmentation += "L";
- Augmentation += "R";
- if (IsSignalFrame)
- Augmentation += "S";
- streamer.EmitBytes(Augmentation.str());
- }
- streamer.EmitIntValue(0, 1);
- // Code Alignment Factor
- if (verboseAsm) streamer.AddComment("CIE Code Alignment Factor");
- streamer.EmitULEB128IntValue(1);
- // Data Alignment Factor
- if (verboseAsm) streamer.AddComment("CIE Data Alignment Factor");
- streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
- // Return Address Register
- if (verboseAsm) streamer.AddComment("CIE Return Address Column");
- streamer.EmitULEB128IntValue(MRI.getDwarfRegNum(MRI.getRARegister(), true));
- // Augmentation Data Length (optional)
- unsigned augmentationLength = 0;
- if (IsEH) {
- if (personality) {
- // Personality Encoding
- augmentationLength += 1;
- // Personality
- augmentationLength += getSizeForEncoding(streamer, personalityEncoding);
- }
- if (lsda)
- augmentationLength += 1;
- // Encoding of the FDE pointers
- augmentationLength += 1;
- if (verboseAsm) streamer.AddComment("Augmentation Size");
- streamer.EmitULEB128IntValue(augmentationLength);
- // Augmentation Data (optional)
- if (personality) {
- // Personality Encoding
- EmitEncodingByte(streamer, personalityEncoding,
- "Personality Encoding");
- // Personality
- if (verboseAsm) streamer.AddComment("Personality");
- EmitPersonality(streamer, *personality, personalityEncoding);
- }
- if (lsda)
- EmitEncodingByte(streamer, lsdaEncoding, "LSDA Encoding");
- // Encoding of the FDE pointers
- EmitEncodingByte(streamer, MOFI->getFDEEncoding(UsingCFI),
- "FDE Encoding");
- }
- // Initial Instructions
- const MCAsmInfo &MAI = context.getAsmInfo();
- const std::vector<MachineMove> &Moves = MAI.getInitialFrameState();
- std::vector<MCCFIInstruction> Instructions;
- for (int i = 0, n = Moves.size(); i != n; ++i) {
- MCSymbol *Label = Moves[i].getLabel();
- const MachineLocation &Dst =
- TranslateMachineLocation(MRI, Moves[i].getDestination());
- const MachineLocation &Src =
- TranslateMachineLocation(MRI, Moves[i].getSource());
- if (Dst.isReg()) {
- assert(Dst.getReg() == MachineLocation::VirtualFP);
- assert(!Src.isReg());
- MCCFIInstruction Inst =
- MCCFIInstruction::createDefCfa(Label, Src.getReg(), -Src.getOffset());
- Instructions.push_back(Inst);
- } else {
- assert(Src.isReg());
- unsigned Reg = Src.getReg();
- int Offset = Dst.getOffset();
- MCCFIInstruction Inst =
- MCCFIInstruction::createOffset(Label, Reg, Offset);
- Instructions.push_back(Inst);
- }
- }
- EmitCFIInstructions(streamer, Instructions, NULL);
- // Padding
- streamer.EmitValueToAlignment(IsEH
- ? 4 : context.getAsmInfo().getPointerSize());
- streamer.EmitLabel(sectionEnd);
- return *sectionStart;
- }
- MCSymbol *FrameEmitterImpl::EmitFDE(MCStreamer &streamer,
- const MCSymbol &cieStart,
- const MCDwarfFrameInfo &frame) {
- MCContext &context = streamer.getContext();
- MCSymbol *fdeStart = context.CreateTempSymbol();
- MCSymbol *fdeEnd = context.CreateTempSymbol();
- const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
- bool verboseAsm = streamer.isVerboseAsm();
- if (IsEH && frame.Function && !MOFI->isFunctionEHFrameSymbolPrivate()) {
- MCSymbol *EHSym =
- context.GetOrCreateSymbol(frame.Function->getName() + Twine(".eh"));
- streamer.EmitEHSymAttributes(frame.Function, EHSym);
- streamer.EmitLabel(EHSym);
- }
- // Length
- const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
- if (verboseAsm) streamer.AddComment("FDE Length");
- streamer.EmitAbsValue(Length, 4);
- streamer.EmitLabel(fdeStart);
- // CIE Pointer
- const MCAsmInfo &asmInfo = context.getAsmInfo();
- if (IsEH) {
- const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
- 0);
- if (verboseAsm) streamer.AddComment("FDE CIE Offset");
- streamer.EmitAbsValue(offset, 4);
- } else if (!asmInfo.doesDwarfUseRelocationsAcrossSections()) {
- const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
- cieStart, 0);
- streamer.EmitAbsValue(offset, 4);
- } else {
- streamer.EmitSymbolValue(&cieStart, 4);
- }
- // PC Begin
- unsigned PCEncoding = IsEH ? MOFI->getFDEEncoding(UsingCFI)
- : (unsigned)dwarf::DW_EH_PE_absptr;
- unsigned PCSize = getSizeForEncoding(streamer, PCEncoding);
- EmitSymbol(streamer, *frame.Begin, PCEncoding, "FDE initial location");
- // PC Range
- const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
- *frame.End, 0);
- if (verboseAsm) streamer.AddComment("FDE address range");
- streamer.EmitAbsValue(Range, PCSize);
- if (IsEH) {
- // Augmentation Data Length
- unsigned augmentationLength = 0;
- if (frame.Lsda)
- augmentationLength += getSizeForEncoding(streamer, frame.LsdaEncoding);
- if (verboseAsm) streamer.AddComment("Augmentation size");
- streamer.EmitULEB128IntValue(augmentationLength);
- // Augmentation Data
- if (frame.Lsda)
- EmitSymbol(streamer, *frame.Lsda, frame.LsdaEncoding,
- "Language Specific Data Area");
- }
- // Call Frame Instructions
- EmitCFIInstructions(streamer, frame.Instructions, frame.Begin);
- // Padding
- streamer.EmitValueToAlignment(PCSize);
- return fdeEnd;
- }
- namespace {
- struct CIEKey {
- static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1, false); }
- static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0, false); }
- CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
- unsigned LsdaEncoding_, bool IsSignalFrame_) :
- Personality(Personality_), PersonalityEncoding(PersonalityEncoding_),
- LsdaEncoding(LsdaEncoding_), IsSignalFrame(IsSignalFrame_) {
- }
- const MCSymbol* Personality;
- unsigned PersonalityEncoding;
- unsigned LsdaEncoding;
- bool IsSignalFrame;
- };
- }
- namespace llvm {
- template <>
- struct DenseMapInfo<CIEKey> {
- static CIEKey getEmptyKey() {
- return CIEKey::getEmptyKey();
- }
- static CIEKey getTombstoneKey() {
- return CIEKey::getTombstoneKey();
- }
- static unsigned getHashValue(const CIEKey &Key) {
- return static_cast<unsigned>(hash_combine(Key.Personality,
- Key.PersonalityEncoding,
- Key.LsdaEncoding,
- Key.IsSignalFrame));
- }
- static bool isEqual(const CIEKey &LHS,
- const CIEKey &RHS) {
- return LHS.Personality == RHS.Personality &&
- LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
- LHS.LsdaEncoding == RHS.LsdaEncoding &&
- LHS.IsSignalFrame == RHS.IsSignalFrame;
- }
- };
- }
- void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
- bool UsingCFI,
- bool IsEH) {
- MCContext &Context = Streamer.getContext();
- MCObjectFileInfo *MOFI =
- const_cast<MCObjectFileInfo*>(Context.getObjectFileInfo());
- FrameEmitterImpl Emitter(UsingCFI, IsEH);
- ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getFrameInfos();
- // Emit the compact unwind info if available.
- if (IsEH && MOFI->getCompactUnwindSection())
- for (unsigned i = 0, n = Streamer.getNumFrameInfos(); i < n; ++i) {
- const MCDwarfFrameInfo &Frame = Streamer.getFrameInfo(i);
- if (Frame.CompactUnwindEncoding)
- Emitter.EmitCompactUnwind(Streamer, Frame);
- }
- const MCSection &Section = IsEH ? *MOFI->getEHFrameSection() :
- *MOFI->getDwarfFrameSection();
- Streamer.SwitchSection(&Section);
- MCSymbol *SectionStart = Context.CreateTempSymbol();
- Streamer.EmitLabel(SectionStart);
- Emitter.setSectionStart(SectionStart);
- MCSymbol *FDEEnd = NULL;
- DenseMap<CIEKey, const MCSymbol*> CIEStarts;
- const MCSymbol *DummyDebugKey = NULL;
- for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
- const MCDwarfFrameInfo &Frame = FrameArray[i];
- CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
- Frame.LsdaEncoding, Frame.IsSignalFrame);
- const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
- if (!CIEStart)
- CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
- Frame.PersonalityEncoding, Frame.Lsda,
- Frame.IsSignalFrame,
- Frame.LsdaEncoding);
- FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
- if (i != n - 1)
- Streamer.EmitLabel(FDEEnd);
- }
- Streamer.EmitValueToAlignment(Context.getAsmInfo().getPointerSize());
- if (FDEEnd)
- Streamer.EmitLabel(FDEEnd);
- }
- void MCDwarfFrameEmitter::EmitAdvanceLoc(MCStreamer &Streamer,
- uint64_t AddrDelta) {
- SmallString<256> Tmp;
- raw_svector_ostream OS(Tmp);
- MCDwarfFrameEmitter::EncodeAdvanceLoc(AddrDelta, OS);
- Streamer.EmitBytes(OS.str());
- }
- void MCDwarfFrameEmitter::EncodeAdvanceLoc(uint64_t AddrDelta,
- raw_ostream &OS) {
- // FIXME: Assumes the code alignment factor is 1.
- if (AddrDelta == 0) {
- } else if (isUIntN(6, AddrDelta)) {
- uint8_t Opcode = dwarf::DW_CFA_advance_loc | AddrDelta;
- OS << Opcode;
- } else if (isUInt<8>(AddrDelta)) {
- OS << uint8_t(dwarf::DW_CFA_advance_loc1);
- OS << uint8_t(AddrDelta);
- } else if (isUInt<16>(AddrDelta)) {
- // FIXME: check what is the correct behavior on a big endian machine.
- OS << uint8_t(dwarf::DW_CFA_advance_loc2);
- OS << uint8_t( AddrDelta & 0xff);
- OS << uint8_t((AddrDelta >> 8) & 0xff);
- } else {
- // FIXME: check what is the correct behavior on a big endian machine.
- assert(isUInt<32>(AddrDelta));
- OS << uint8_t(dwarf::DW_CFA_advance_loc4);
- OS << uint8_t( AddrDelta & 0xff);
- OS << uint8_t((AddrDelta >> 8) & 0xff);
- OS << uint8_t((AddrDelta >> 16) & 0xff);
- OS << uint8_t((AddrDelta >> 24) & 0xff);
- }
- }
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