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-rw-r--r--contrib/llvm/lib/MC/MCDwarf.cpp1086
1 files changed, 1086 insertions, 0 deletions
diff --git a/contrib/llvm/lib/MC/MCDwarf.cpp b/contrib/llvm/lib/MC/MCDwarf.cpp
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--- /dev/null
+++ b/contrib/llvm/lib/MC/MCDwarf.cpp
@@ -0,0 +1,1086 @@
+//===- 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/MCAsmInfo.h"
+#include "llvm/MC/MCDwarf.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetAsmInfo.h"
+#include "llvm/ADT/FoldingSet.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Twine.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);
+}
+
+//
+// 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 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()->begin(),
+ ie = LineSection->getMCLineEntries()->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 the dwarf line section.
+ MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
+
+ const MCAsmInfo &asmInfo = MCOS->getContext().getAsmInfo();
+ MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
+ asmInfo.getPointerSize());
+}
+
+//
+// This emits the Dwarf file and the line tables.
+//
+void MCDwarfFileTable::Emit(MCStreamer *MCOS) {
+ MCContext &context = MCOS->getContext();
+ // Switch to the section where the table will be emitted into.
+ MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
+
+ // Create a symbol at the beginning of this section.
+ MCSymbol *LineStartSym = context.CreateTempSymbol();
+ // Set the value of the symbol, as we are at the start of the section.
+ 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 std::vector<StringRef> &MCDwarfDirs =
+ context.getMCDwarfDirs();
+ for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
+ MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
+ MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
+ }
+ MCOS->EmitIntValue(0, 1); // Terminate the directory list
+
+ // Second the file table.
+ const std::vector<MCDwarfFile *> &MCDwarfFiles =
+ MCOS->getContext().getMCDwarfFiles();
+ for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
+ MCOS->EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
+ MCOS->EmitBytes(StringRef("\0", 1), 0); // 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);
+
+ // Now delete the MCLineSections that were created in MCLineEntry::Make()
+ // and used to emit the line table.
+ delete Line;
+ }
+
+ 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);
+}
+
+/// 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(), /*AddrSpace=*/0);
+}
+
+/// 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);
+ MCObjectWriter::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);
+ SmallString<32> Tmp;
+ raw_svector_ostream OSE(Tmp);
+ MCObjectWriter::EncodeSLEB128(LineDelta, OSE);
+ OS << OSE.str();
+
+ 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);
+ SmallString<32> Tmp;
+ raw_svector_ostream OSE(Tmp);
+ MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
+ OS << OSE.str();
+
+ if (NeedCopy)
+ OS << char(dwarf::DW_LNS_copy);
+ else
+ OS << char(Temp);
+}
+
+void MCDwarfFile::print(raw_ostream &OS) const {
+ OS << '"' << getName() << '"';
+}
+
+void MCDwarfFile::dump() const {
+ print(dbgs());
+}
+
+static int getDataAlignmentFactor(MCStreamer &streamer) {
+ MCContext &context = streamer.getContext();
+ const MCAsmInfo &asmInfo = context.getAsmInfo();
+ int size = asmInfo.getPointerSize();
+ 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:
+ assert(0 && "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 TargetAsmInfo &TAI,
+ const MachineLocation &Loc) {
+ unsigned Reg = Loc.getReg() == MachineLocation::VirtualFP ?
+ MachineLocation::VirtualFP :
+ unsigned(TAI.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, const MCSymbol *sectionStart) :
+ CFAOffset(0), CIENum(0), UsingCFI(usingCFI), IsEH(isEH),
+ SectionStart(sectionStart) {
+ }
+
+ /// 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,
+ 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 = 0;
+ switch (Encoding) {
+ default: EncStr = "<unknown encoding>";
+ case dwarf::DW_EH_PE_absptr: EncStr = "absptr";
+ case dwarf::DW_EH_PE_omit: EncStr = "omit";
+ case dwarf::DW_EH_PE_pcrel: EncStr = "pcrel";
+ case dwarf::DW_EH_PE_udata4: EncStr = "udata4";
+ case dwarf::DW_EH_PE_udata8: EncStr = "udata8";
+ case dwarf::DW_EH_PE_sdata4: EncStr = "sdata4";
+ case dwarf::DW_EH_PE_sdata8: EncStr = "sdata8";
+ case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata4: EncStr = "pcrel udata4";
+ case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata4: EncStr = "pcrel sdata4";
+ case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata8: EncStr = "pcrel udata8";
+ case dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata8: EncStr = "pcrel sdata8";
+ case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata4:
+ EncStr = "indirect pcrel udata4";
+ case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata4:
+ EncStr = "indirect pcrel sdata4";
+ case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_udata8:
+ EncStr = "indirect pcrel udata8";
+ case dwarf::DW_EH_PE_indirect |dwarf::DW_EH_PE_pcrel|dwarf::DW_EH_PE_sdata8:
+ EncStr = "indirect pcrel sdata8";
+ }
+
+ 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::Move:
+ case MCCFIInstruction::RelMove: {
+ const MachineLocation &Dst = Instr.getDestination();
+ const MachineLocation &Src = Instr.getSource();
+ const bool IsRelative = Instr.getOperation() == MCCFIInstruction::RelMove;
+
+ // If advancing cfa.
+ if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
+ if (Src.getReg() == MachineLocation::VirtualFP) {
+ if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa_offset");
+ Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
+ } else {
+ if (VerboseAsm) Streamer.AddComment("DW_CFA_def_cfa");
+ Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
+ if (VerboseAsm) Streamer.AddComment(Twine("Reg ") +
+ Twine(Src.getReg()));
+ Streamer.EmitULEB128IntValue(Src.getReg());
+ }
+
+ if (IsRelative)
+ CFAOffset += Src.getOffset();
+ else
+ CFAOffset = -Src.getOffset();
+
+ if (VerboseAsm) Streamer.AddComment(Twine("Offset " + Twine(CFAOffset)));
+ Streamer.EmitULEB128IntValue(CFAOffset);
+ return;
+ }
+
+ if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
+ assert(Dst.isReg() && "Machine move not supported yet.");
+ 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(Dst.getReg()));
+ Streamer.EmitULEB128IntValue(Dst.getReg());
+ return;
+ }
+
+ unsigned Reg = Src.getReg();
+ int Offset = Dst.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::Remember:
+ if (VerboseAsm) Streamer.AddComment("DW_CFA_remember_state");
+ Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
+ return;
+ case MCCFIInstruction::Restore:
+ if (VerboseAsm) Streamer.AddComment("DW_CFA_restore_state");
+ Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
+ return;
+ case MCCFIInstruction::SameValue: {
+ unsigned Reg = Instr.getDestination().getReg();
+ 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;
+ }
+ }
+ 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) {
+#if 1
+ return false;
+#else
+ MCContext &Context = Streamer.getContext();
+ const TargetAsmInfo &TAI = Context.getTargetAsmInfo();
+ 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 =
+ TAI.getCompactUnwindEncoding(Frame.Instructions,
+ getDataAlignmentFactor(Streamer), IsEH);
+ if (!Encoding) return false;
+
+ // The encoding needs to know we have an LSDA.
+ if (Frame.Lsda)
+ Encoding |= 0x40000000;
+
+ Streamer.SwitchSection(TAI.getCompactUnwindSection());
+
+ // Range Start
+ unsigned FDEEncoding = TAI.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(Twine("Compact Unwind Encoding: 0x") +
+ Twine(llvm::utohexstr(Encoding)));
+ Streamer.EmitIntValue(Encoding, Size);
+
+ // Personality Function
+ Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
+ if (VerboseAsm) Streamer.AddComment("Personality Function");
+ if (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 (Frame.Lsda)
+ Streamer.EmitSymbolValue(Frame.Lsda, Size);
+ else
+ Streamer.EmitIntValue(0, Size); // No LSDA
+
+ return true;
+#endif
+}
+
+const MCSymbol &FrameEmitterImpl::EmitCIE(MCStreamer &streamer,
+ const MCSymbol *personality,
+ unsigned personalityEncoding,
+ const MCSymbol *lsda,
+ unsigned lsdaEncoding) {
+ MCContext &context = streamer.getContext();
+ const TargetAsmInfo &TAI = context.getTargetAsmInfo();
+ bool verboseAsm = streamer.isVerboseAsm();
+
+ MCSymbol *sectionStart;
+ if (TAI.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";
+ streamer.EmitBytes(Augmentation.str(), 0);
+ }
+ 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(TAI.getDwarfRARegNum(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, TAI.getFDEEncoding(UsingCFI),
+ "FDE Encoding");
+ }
+
+ // Initial Instructions
+
+ const std::vector<MachineMove> &Moves = TAI.getInitialFrameState();
+ std::vector<MCCFIInstruction> Instructions;
+
+ for (int i = 0, n = Moves.size(); i != n; ++i) {
+ MCSymbol *Label = Moves[i].getLabel();
+ const MachineLocation &Dst =
+ TranslateMachineLocation(TAI, Moves[i].getDestination());
+ const MachineLocation &Src =
+ TranslateMachineLocation(TAI, Moves[i].getSource());
+ MCCFIInstruction Inst(Label, Dst, Src);
+ 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 TargetAsmInfo &TAI = context.getTargetAsmInfo();
+ bool verboseAsm = streamer.isVerboseAsm();
+
+ if (!TAI.isFunctionEHFrameSymbolPrivate() && IsEH) {
+ 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.doesDwarfRequireRelocationForSectionOffset()) {
+ const MCExpr *offset = MakeStartMinusEndExpr(streamer, *SectionStart,
+ cieStart, 0);
+ streamer.EmitAbsValue(offset, 4);
+ } else {
+ streamer.EmitSymbolValue(&cieStart, 4);
+ }
+
+ unsigned fdeEncoding = TAI.getFDEEncoding(UsingCFI);
+ unsigned size = getSizeForEncoding(streamer, fdeEncoding);
+
+ // PC Begin
+ unsigned PCBeginEncoding = IsEH ? fdeEncoding :
+ (unsigned)dwarf::DW_EH_PE_absptr;
+ unsigned PCBeginSize = getSizeForEncoding(streamer, PCBeginEncoding);
+ EmitSymbol(streamer, *frame.Begin, PCBeginEncoding, "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, size);
+
+ 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(PCBeginSize);
+
+ return fdeEnd;
+}
+
+namespace {
+ struct CIEKey {
+ static const CIEKey getEmptyKey() { return CIEKey(0, 0, -1); }
+ static const CIEKey getTombstoneKey() { return CIEKey(0, -1, 0); }
+
+ CIEKey(const MCSymbol* Personality_, unsigned PersonalityEncoding_,
+ unsigned LsdaEncoding_) : Personality(Personality_),
+ PersonalityEncoding(PersonalityEncoding_),
+ LsdaEncoding(LsdaEncoding_) {
+ }
+ const MCSymbol* Personality;
+ unsigned PersonalityEncoding;
+ unsigned LsdaEncoding;
+ };
+}
+
+namespace llvm {
+ template <>
+ struct DenseMapInfo<CIEKey> {
+ static CIEKey getEmptyKey() {
+ return CIEKey::getEmptyKey();
+ }
+ static CIEKey getTombstoneKey() {
+ return CIEKey::getTombstoneKey();
+ }
+ static unsigned getHashValue(const CIEKey &Key) {
+ FoldingSetNodeID ID;
+ ID.AddPointer(Key.Personality);
+ ID.AddInteger(Key.PersonalityEncoding);
+ ID.AddInteger(Key.LsdaEncoding);
+ return ID.ComputeHash();
+ }
+ static bool isEqual(const CIEKey &LHS,
+ const CIEKey &RHS) {
+ return LHS.Personality == RHS.Personality &&
+ LHS.PersonalityEncoding == RHS.PersonalityEncoding &&
+ LHS.LsdaEncoding == RHS.LsdaEncoding;
+ }
+ };
+}
+
+void MCDwarfFrameEmitter::Emit(MCStreamer &Streamer,
+ bool UsingCFI,
+ bool IsEH) {
+ MCContext &Context = Streamer.getContext();
+ const TargetAsmInfo &TAI = Context.getTargetAsmInfo();
+ const MCSection &Section = IsEH ? *TAI.getEHFrameSection() :
+ *TAI.getDwarfFrameSection();
+ Streamer.SwitchSection(&Section);
+ MCSymbol *SectionStart = Context.CreateTempSymbol();
+ Streamer.EmitLabel(SectionStart);
+
+ MCSymbol *FDEEnd = NULL;
+ DenseMap<CIEKey, const MCSymbol*> CIEStarts;
+ FrameEmitterImpl Emitter(UsingCFI, IsEH, SectionStart);
+
+ const MCSymbol *DummyDebugKey = NULL;
+ for (unsigned i = 0, n = Streamer.getNumFrameInfos(); i < n; ++i) {
+ const MCDwarfFrameInfo &Frame = Streamer.getFrameInfo(i);
+ if (IsEH && TAI.getCompactUnwindSection() &&
+ Emitter.EmitCompactUnwind(Streamer, Frame)) {
+ FDEEnd = NULL;
+ continue;
+ }
+
+ CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
+ Frame.LsdaEncoding);
+ const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
+ if (!CIEStart)
+ CIEStart = &Emitter.EmitCIE(Streamer, Frame.Personality,
+ Frame.PersonalityEncoding, Frame.Lsda,
+ 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(), /*AddrSpace=*/0);
+}
+
+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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