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-rw-r--r--contrib/llvm/lib/MC/MCDwarf.cpp1583
1 files changed, 1583 insertions, 0 deletions
diff --git a/contrib/llvm/lib/MC/MCDwarf.cpp b/contrib/llvm/lib/MC/MCDwarf.cpp
new file mode 100644
index 0000000..a99ac4e
--- /dev/null
+++ b/contrib/llvm/lib/MC/MCDwarf.cpp
@@ -0,0 +1,1583 @@
+//===- 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/STLExtras.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/MCObjectStreamer.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSection.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;
+
+static inline uint64_t ScaleAddrDelta(MCContext &Context, uint64_t AddrDelta) {
+ unsigned MinInsnLength = Context.getAsmInfo()->getMinInstAlignment();
+ if (MinInsnLength == 1)
+ return AddrDelta;
+ if (AddrDelta % MinInsnLength != 0) {
+ // TODO: report this error, but really only once.
+ ;
+ }
+ return AddrDelta / MinInsnLength;
+}
+
+//
+// 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(MCObjectStreamer *MCOS, 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();
+
+ // Add the line entry to this section's entries.
+ MCOS->getContext()
+ .getMCDwarfLineTable(MCOS->getContext().getDwarfCompileUnitID())
+ .getMCLineSections()
+ .addLineEntry(LineEntry, Section);
+}
+
+//
+// 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(MCObjectStreamer *MCOS, MCSection *Section,
+ const MCLineSection::MCLineEntryCollection &LineEntries) {
+ unsigned FileNum = 1;
+ unsigned LastLine = 1;
+ unsigned Column = 0;
+ unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
+ unsigned Isa = 0;
+ unsigned Discriminator = 0;
+ MCSymbol *LastLabel = nullptr;
+
+ // Loop through each MCLineEntry and encode the dwarf line number table.
+ for (auto it = LineEntries.begin(),
+ ie = LineEntries.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 (Discriminator != it->getDiscriminator()) {
+ Discriminator = it->getDiscriminator();
+ unsigned Size = getULEB128Size(Discriminator);
+ MCOS->EmitIntValue(dwarf::DW_LNS_extended_op, 1);
+ MCOS->EmitULEB128IntValue(Size + 1);
+ MCOS->EmitIntValue(dwarf::DW_LNE_set_discriminator, 1);
+ MCOS->EmitULEB128IntValue(Discriminator);
+ }
+ 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.
+ // Use the section end label 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.
+ MCSymbol *SectionEnd = MCOS->endSection(Section);
+
+ // Switch back the dwarf line section, in case endSection had to switch the
+ // section.
+ MCContext &Ctx = MCOS->getContext();
+ MCOS->SwitchSection(Ctx.getObjectFileInfo()->getDwarfLineSection());
+
+ const MCAsmInfo *AsmInfo = Ctx.getAsmInfo();
+ MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
+ AsmInfo->getPointerSize());
+}
+
+//
+// This emits the Dwarf file and the line tables.
+//
+void MCDwarfLineTable::Emit(MCObjectStreamer *MCOS,
+ MCDwarfLineTableParams Params) {
+ MCContext &context = MCOS->getContext();
+
+ auto &LineTables = context.getMCDwarfLineTables();
+
+ // Bail out early so we don't switch to the debug_line section needlessly and
+ // in doing so create an unnecessary (if empty) section.
+ if (LineTables.empty())
+ return;
+
+ // Switch to the section where the table will be emitted into.
+ MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
+
+ // Handle the rest of the Compile Units.
+ for (const auto &CUIDTablePair : LineTables)
+ CUIDTablePair.second.EmitCU(MCOS, Params);
+}
+
+void MCDwarfDwoLineTable::Emit(MCStreamer &MCOS,
+ MCDwarfLineTableParams Params) const {
+ MCOS.EmitLabel(Header.Emit(&MCOS, Params, None).second);
+}
+
+std::pair<MCSymbol *, MCSymbol *>
+MCDwarfLineTableHeader::Emit(MCStreamer *MCOS,
+ MCDwarfLineTableParams Params) const {
+ static const char StandardOpcodeLengths[] = {
+ 0, // length of DW_LNS_copy
+ 1, // length of DW_LNS_advance_pc
+ 1, // length of DW_LNS_advance_line
+ 1, // length of DW_LNS_set_file
+ 1, // length of DW_LNS_set_column
+ 0, // length of DW_LNS_negate_stmt
+ 0, // length of DW_LNS_set_basic_block
+ 0, // length of DW_LNS_const_add_pc
+ 1, // length of DW_LNS_fixed_advance_pc
+ 0, // length of DW_LNS_set_prologue_end
+ 0, // length of DW_LNS_set_epilogue_begin
+ 1 // DW_LNS_set_isa
+ };
+ assert(array_lengthof(StandardOpcodeLengths) >=
+ (Params.DWARF2LineOpcodeBase - 1U));
+ return Emit(MCOS, Params, makeArrayRef(StandardOpcodeLengths,
+ Params.DWARF2LineOpcodeBase - 1));
+}
+
+static const MCExpr *forceExpAbs(MCStreamer &OS, const MCExpr* Expr) {
+ MCContext &Context = OS.getContext();
+ assert(!isa<MCSymbolRefExpr>(Expr));
+ if (Context.getAsmInfo()->hasAggressiveSymbolFolding())
+ return Expr;
+
+ MCSymbol *ABS = Context.createTempSymbol();
+ OS.EmitAssignment(ABS, Expr);
+ return MCSymbolRefExpr::create(ABS, Context);
+}
+
+static void emitAbsValue(MCStreamer &OS, const MCExpr *Value, unsigned Size) {
+ const MCExpr *ABS = forceExpAbs(OS, Value);
+ OS.EmitValue(ABS, Size);
+}
+
+std::pair<MCSymbol *, MCSymbol *>
+MCDwarfLineTableHeader::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
+ ArrayRef<char> StandardOpcodeLengths) const {
+ MCContext &context = MCOS->getContext();
+
+ // Create a symbol at the beginning of the line table.
+ MCSymbol *LineStartSym = Label;
+ 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).
+ emitAbsValue(*MCOS,
+ 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.
+ emitAbsValue(
+ *MCOS,
+ MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym, (4 + 2 + 4)), 4);
+
+ // Parameters of the state machine, are next.
+ MCOS->EmitIntValue(context.getAsmInfo()->getMinInstAlignment(), 1);
+ MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
+ MCOS->EmitIntValue(Params.DWARF2LineBase, 1);
+ MCOS->EmitIntValue(Params.DWARF2LineRange, 1);
+ MCOS->EmitIntValue(StandardOpcodeLengths.size() + 1, 1);
+
+ // Standard opcode lengths
+ for (char Length : StandardOpcodeLengths)
+ MCOS->EmitIntValue(Length, 1);
+
+ // Put out the directory and file tables.
+
+ // First the directory table.
+ 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.
+ for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
+ assert(!MCDwarfFiles[i].Name.empty());
+ MCOS->EmitBytes(MCDwarfFiles[i].Name); // FileName
+ MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
+ // the Directory num
+ MCOS->EmitULEB128IntValue(MCDwarfFiles[i].DirIndex);
+ 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);
+
+ return std::make_pair(LineStartSym, LineEndSym);
+}
+
+void MCDwarfLineTable::EmitCU(MCObjectStreamer *MCOS,
+ MCDwarfLineTableParams Params) const {
+ MCSymbol *LineEndSym = Header.Emit(MCOS, Params).second;
+
+ // Put out the line tables.
+ for (const auto &LineSec : MCLineSections.getMCLineEntries())
+ EmitDwarfLineTable(MCOS, LineSec.first, LineSec.second);
+
+ // 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);
+}
+
+unsigned MCDwarfLineTable::getFile(StringRef &Directory, StringRef &FileName,
+ unsigned FileNumber) {
+ return Header.getFile(Directory, FileName, FileNumber);
+}
+
+unsigned MCDwarfLineTableHeader::getFile(StringRef &Directory,
+ StringRef &FileName,
+ unsigned FileNumber) {
+ if (Directory == CompilationDir)
+ Directory = "";
+ if (FileName.empty()) {
+ FileName = "<stdin>";
+ Directory = "";
+ }
+ assert(!FileName.empty());
+ if (FileNumber == 0) {
+ FileNumber = SourceIdMap.size() + 1;
+ assert((MCDwarfFiles.empty() || FileNumber == MCDwarfFiles.size()) &&
+ "Don't mix autonumbered and explicit numbered line table usage");
+ SmallString<256> Buffer;
+ auto IterBool = SourceIdMap.insert(
+ std::make_pair((Directory + Twine('\0') + FileName).toStringRef(Buffer),
+ FileNumber));
+ if (!IterBool.second)
+ return IterBool.first->second;
+ }
+ // Make space for this FileNumber in the MCDwarfFiles vector if needed.
+ MCDwarfFiles.resize(FileNumber + 1);
+
+ // Get the new MCDwarfFile slot for this FileNumber.
+ MCDwarfFile &File = MCDwarfFiles[FileNumber];
+
+ // It is an error to use see the same number more than once.
+ if (!File.Name.empty())
+ return 0;
+
+ if (Directory.empty()) {
+ // Separate the directory part from the basename of the FileName.
+ StringRef tFileName = sys::path::filename(FileName);
+ if (!tFileName.empty()) {
+ Directory = sys::path::parent_path(FileName);
+ if (!Directory.empty())
+ FileName = tFileName;
+ }
+ }
+
+ // Find or make an entry in the MCDwarfDirs vector for this Directory.
+ // Capture directory name.
+ unsigned DirIndex;
+ if (Directory.empty()) {
+ // For FileNames with no directories a DirIndex of 0 is used.
+ DirIndex = 0;
+ } else {
+ DirIndex = 0;
+ for (unsigned End = MCDwarfDirs.size(); DirIndex < End; DirIndex++) {
+ if (Directory == MCDwarfDirs[DirIndex])
+ break;
+ }
+ if (DirIndex >= MCDwarfDirs.size())
+ MCDwarfDirs.push_back(Directory);
+ // The DirIndex is one based, as DirIndex of 0 is used for FileNames with
+ // no directories. MCDwarfDirs[] is unlike MCDwarfFiles[] in that the
+ // directory names are stored at MCDwarfDirs[DirIndex-1] where FileNames
+ // are stored at MCDwarfFiles[FileNumber].Name .
+ DirIndex++;
+ }
+
+ File.Name = FileName;
+ File.DirIndex = DirIndex;
+
+ // return the allocated FileNumber.
+ return FileNumber;
+}
+
+/// Utility function to emit the encoding to a streamer.
+void MCDwarfLineAddr::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
+ int64_t LineDelta, uint64_t AddrDelta) {
+ MCContext &Context = MCOS->getContext();
+ SmallString<256> Tmp;
+ raw_svector_ostream OS(Tmp);
+ MCDwarfLineAddr::Encode(Context, Params, LineDelta, AddrDelta, OS);
+ MCOS->EmitBytes(OS.str());
+}
+
+/// Given a special op, return the address skip amount (in units of
+/// DWARF2_LINE_MIN_INSN_LENGTH).
+static uint64_t SpecialAddr(MCDwarfLineTableParams Params, uint64_t op) {
+ return (op - Params.DWARF2LineOpcodeBase) / Params.DWARF2LineRange;
+}
+
+/// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
+void MCDwarfLineAddr::Encode(MCContext &Context, MCDwarfLineTableParams Params,
+ int64_t LineDelta, uint64_t AddrDelta,
+ raw_ostream &OS) {
+ uint64_t Temp, Opcode;
+ bool NeedCopy = false;
+
+ // The maximum address skip amount that can be encoded with a special op.
+ uint64_t MaxSpecialAddrDelta = SpecialAddr(Params, 255);
+
+ // Scale the address delta by the minimum instruction length.
+ AddrDelta = ScaleAddrDelta(Context, 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 == MaxSpecialAddrDelta)
+ OS << char(dwarf::DW_LNS_const_add_pc);
+ else if (AddrDelta) {
+ 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 - Params.DWARF2LineBase;
+
+ // If the line increment is out of range of a special opcode, we must encode
+ // it with DW_LNS_advance_line.
+ if (Temp >= Params.DWARF2LineRange) {
+ OS << char(dwarf::DW_LNS_advance_line);
+ encodeSLEB128(LineDelta, OS);
+
+ LineDelta = 0;
+ Temp = 0 - Params.DWARF2LineBase;
+ 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 += Params.DWARF2LineOpcodeBase;
+
+ // Avoid overflow when addr_delta is large.
+ if (AddrDelta < 256 + MaxSpecialAddrDelta) {
+ // Try using a special opcode.
+ Opcode = Temp + AddrDelta * Params.DWARF2LineRange;
+ if (Opcode <= 255) {
+ OS << char(Opcode);
+ return;
+ }
+
+ // Try using DW_LNS_const_add_pc followed by special op.
+ Opcode = Temp + (AddrDelta - MaxSpecialAddrDelta) * Params.DWARF2LineRange;
+ 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);
+}
+
+// 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,
+ context.getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
+ : dwarf::DW_FORM_data4);
+ if (context.getGenDwarfSectionSyms().size() > 1 &&
+ context.getDwarfVersion() >= 3) {
+ EmitAbbrev(MCOS, dwarf::DW_AT_ranges,
+ context.getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
+ : dwarf::DW_FORM_data4);
+ } else {
+ 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);
+ if (!context.getCompilationDir().empty())
+ 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. This section contains a header and a table of pairs
+// of PointerSize'ed values for the address and size of section(s) with line
+// table entries.
+static void EmitGenDwarfAranges(MCStreamer *MCOS,
+ const MCSymbol *InfoSectionSymbol) {
+ MCContext &context = MCOS->getContext();
+
+ auto &Sections = context.getGenDwarfSectionSyms();
+
+ 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 each section we have in the table.
+ Length += 2 * AddrSize * Sections.size();
+ // 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,
+ asmInfo->needsDwarfSectionOffsetDirective());
+ 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
+ // addresses and sizes.
+ for (MCSection *Sec : Sections) {
+ const MCSymbol *StartSymbol = Sec->getBeginSymbol();
+ MCSymbol *EndSymbol = Sec->getEndSymbol(context);
+ assert(StartSymbol && "StartSymbol must not be NULL");
+ assert(EndSymbol && "EndSymbol must not be NULL");
+
+ const MCExpr *Addr = MCSymbolRefExpr::create(
+ StartSymbol, MCSymbolRefExpr::VK_None, context);
+ const MCExpr *Size = MakeStartMinusEndExpr(*MCOS,
+ *StartSymbol, *EndSymbol, 0);
+ MCOS->EmitValue(Addr, AddrSize);
+ emitAbsValue(*MCOS, 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,
+ const MCSymbol *RangesSectionSymbol) {
+ 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);
+ emitAbsValue(*MCOS, Length, 4);
+
+ // The 2 byte DWARF version.
+ MCOS->EmitIntValue(context.getDwarfVersion(), 2);
+
+ const MCAsmInfo &AsmInfo = *context.getAsmInfo();
+ // 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 == nullptr)
+ MCOS->EmitIntValue(0, 4);
+ else
+ MCOS->EmitSymbolValue(AbbrevSectionSymbol, 4,
+ AsmInfo.needsDwarfSectionOffsetDirective());
+
+ 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,
+ AsmInfo.needsDwarfSectionOffsetDirective());
+ else
+ MCOS->EmitIntValue(0, 4);
+
+ if (RangesSectionSymbol) {
+ // There are multiple sections containing code, so we must use the
+ // .debug_ranges sections.
+
+ // AT_ranges, the 4 byte offset from the start of the .debug_ranges section
+ // to the address range list for this compilation unit.
+ MCOS->EmitSymbolValue(RangesSectionSymbol, 4);
+ } else {
+ // If we only have one non-empty code section, we can use the simpler
+ // AT_low_pc and AT_high_pc attributes.
+
+ // Find the first (and only) non-empty text section
+ auto &Sections = context.getGenDwarfSectionSyms();
+ const auto TextSection = Sections.begin();
+ assert(TextSection != Sections.end() && "No text section found");
+
+ MCSymbol *StartSymbol = (*TextSection)->getBeginSymbol();
+ MCSymbol *EndSymbol = (*TextSection)->getEndSymbol(context);
+ assert(StartSymbol && "StartSymbol must not be NULL");
+ assert(EndSymbol && "EndSymbol must not be NULL");
+
+ // AT_low_pc, the first address of the default .text section.
+ const MCExpr *Start = MCSymbolRefExpr::create(
+ StartSymbol, MCSymbolRefExpr::VK_None, context);
+ MCOS->EmitValue(Start, AddrSize);
+
+ // AT_high_pc, the last address of the default .text section.
+ const MCExpr *End = MCSymbolRefExpr::create(
+ EndSymbol, MCSymbolRefExpr::VK_None, context);
+ MCOS->EmitValue(End, AddrSize);
+ }
+
+ // AT_name, the name of the source file. Reconstruct from the first directory
+ // and file table entries.
+ const SmallVectorImpl<std::string> &MCDwarfDirs = context.getMCDwarfDirs();
+ if (MCDwarfDirs.size() > 0) {
+ MCOS->EmitBytes(MCDwarfDirs[0]);
+ MCOS->EmitBytes(sys::path::get_separator());
+ }
+ const SmallVectorImpl<MCDwarfFile> &MCDwarfFiles =
+ MCOS->getContext().getMCDwarfFiles();
+ MCOS->EmitBytes(MCDwarfFiles[1].Name);
+ MCOS->EmitIntValue(0, 1); // NULL byte to terminate the string.
+
+ // AT_comp_dir, the working directory the assembly was done in.
+ if (!context.getCompilationDir().empty()) {
+ 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 " PACKAGE_VERSION ")"));
+ 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<MCGenDwarfLabelEntry> &Entries =
+ MCOS->getContext().getMCGenDwarfLabelEntries();
+ for (const auto &Entry : Entries) {
+ // 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->EmitValue(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);
+ }
+
+ // 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 data for
+// .debug_ranges section. We only emit one range list, which spans all of the
+// executable sections of this file.
+static void EmitGenDwarfRanges(MCStreamer *MCOS) {
+ MCContext &context = MCOS->getContext();
+ auto &Sections = context.getGenDwarfSectionSyms();
+
+ const MCAsmInfo *AsmInfo = context.getAsmInfo();
+ int AddrSize = AsmInfo->getPointerSize();
+
+ MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfRangesSection());
+
+ for (MCSection *Sec : Sections) {
+ const MCSymbol *StartSymbol = Sec->getBeginSymbol();
+ MCSymbol *EndSymbol = Sec->getEndSymbol(context);
+ assert(StartSymbol && "StartSymbol must not be NULL");
+ assert(EndSymbol && "EndSymbol must not be NULL");
+
+ // Emit a base address selection entry for the start of this section
+ const MCExpr *SectionStartAddr = MCSymbolRefExpr::create(
+ StartSymbol, MCSymbolRefExpr::VK_None, context);
+ MCOS->EmitFill(AddrSize, 0xFF);
+ MCOS->EmitValue(SectionStartAddr, AddrSize);
+
+ // Emit a range list entry spanning this section
+ const MCExpr *SectionSize = MakeStartMinusEndExpr(*MCOS,
+ *StartSymbol, *EndSymbol, 0);
+ MCOS->EmitIntValue(0, AddrSize);
+ emitAbsValue(*MCOS, SectionSize, AddrSize);
+ }
+
+ // Emit end of list entry
+ MCOS->EmitIntValue(0, AddrSize);
+ MCOS->EmitIntValue(0, AddrSize);
+}
+
+//
+// When generating dwarf for assembly source files this emits the Dwarf
+// sections.
+//
+void MCGenDwarfInfo::Emit(MCStreamer *MCOS) {
+ MCContext &context = MCOS->getContext();
+
+ // Create the dwarf sections in this order (.debug_line already created).
+ const MCAsmInfo *AsmInfo = context.getAsmInfo();
+ bool CreateDwarfSectionSymbols =
+ AsmInfo->doesDwarfUseRelocationsAcrossSections();
+ MCSymbol *LineSectionSymbol = nullptr;
+ if (CreateDwarfSectionSymbols)
+ LineSectionSymbol = MCOS->getDwarfLineTableSymbol(0);
+ MCSymbol *AbbrevSectionSymbol = nullptr;
+ MCSymbol *InfoSectionSymbol = nullptr;
+ MCSymbol *RangesSectionSymbol = nullptr;
+
+ // Create end symbols for each section, and remove empty sections
+ MCOS->getContext().finalizeDwarfSections(*MCOS);
+
+ // If there are no sections to generate debug info for, we don't need
+ // to do anything
+ if (MCOS->getContext().getGenDwarfSectionSyms().empty())
+ return;
+
+ // We only use the .debug_ranges section if we have multiple code sections,
+ // and we are emitting a DWARF version which supports it.
+ const bool UseRangesSection =
+ MCOS->getContext().getGenDwarfSectionSyms().size() > 1 &&
+ MCOS->getContext().getDwarfVersion() >= 3;
+ CreateDwarfSectionSymbols |= UseRangesSection;
+
+ 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);
+ }
+ if (UseRangesSection) {
+ MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfRangesSection());
+ if (CreateDwarfSectionSymbols) {
+ RangesSectionSymbol = context.createTempSymbol();
+ MCOS->EmitLabel(RangesSectionSymbol);
+ }
+ }
+
+ assert((RangesSectionSymbol != NULL) || !UseRangesSection);
+
+ MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfARangesSection());
+
+ // Output the data for .debug_aranges section.
+ EmitGenDwarfAranges(MCOS, InfoSectionSymbol);
+
+ if (UseRangesSection)
+ EmitGenDwarfRanges(MCOS);
+
+ // Output the data for .debug_abbrev section.
+ EmitGenDwarfAbbrev(MCOS);
+
+ // Output the data for .debug_info section.
+ EmitGenDwarfInfo(MCOS, AbbrevSectionSymbol, LineSectionSymbol,
+ RangesSectionSymbol);
+}
+
+//
+// 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.
+ if (Symbol->isTemporary())
+ return;
+ MCContext &context = MCOS->getContext();
+ // We won't create dwarf labels for symbols in sections that we are not
+ // generating debug info for.
+ if (!context.getGenDwarfSectionSyms().count(MCOS->getCurrentSection().first))
+ 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.
+ unsigned 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.
+ MCOS->getContext().addMCGenDwarfLabelEntry(
+ MCGenDwarfLabelEntry(Name, FileNumber, LineNumber, Label));
+}
+
+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 emitFDESymbol(MCObjectStreamer &streamer, const MCSymbol &symbol,
+ unsigned symbolEncoding, bool isEH) {
+ MCContext &context = streamer.getContext();
+ const MCAsmInfo *asmInfo = context.getAsmInfo();
+ const MCExpr *v = asmInfo->getExprForFDESymbol(&symbol,
+ symbolEncoding,
+ streamer);
+ unsigned size = getSizeForEncoding(streamer, symbolEncoding);
+ if (asmInfo->doDwarfFDESymbolsUseAbsDiff() && isEH)
+ emitAbsValue(streamer, v, size);
+ else
+ streamer.EmitValue(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);
+}
+
+namespace {
+class FrameEmitterImpl {
+ int CFAOffset = 0;
+ int InitialCFAOffset = 0;
+ bool IsEH;
+ MCObjectStreamer &Streamer;
+
+public:
+ FrameEmitterImpl(bool IsEH, MCObjectStreamer &Streamer)
+ : IsEH(IsEH), Streamer(Streamer) {}
+
+ /// Emit the unwind information in a compact way.
+ void EmitCompactUnwind(const MCDwarfFrameInfo &frame);
+
+ const MCSymbol &EmitCIE(const MCSymbol *personality,
+ unsigned personalityEncoding, const MCSymbol *lsda,
+ bool IsSignalFrame, unsigned lsdaEncoding,
+ bool IsSimple);
+ void EmitFDE(const MCSymbol &cieStart, const MCDwarfFrameInfo &frame,
+ bool LastInSection, const MCSymbol &SectionStart);
+ void EmitCFIInstructions(ArrayRef<MCCFIInstruction> Instrs,
+ MCSymbol *BaseLabel);
+ void EmitCFIInstruction(const MCCFIInstruction &Instr);
+};
+
+} // end anonymous namespace
+
+static void emitEncodingByte(MCObjectStreamer &Streamer, unsigned Encoding) {
+ Streamer.EmitIntValue(Encoding, 1);
+}
+
+void FrameEmitterImpl::EmitCFIInstruction(const MCCFIInstruction &Instr) {
+ int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
+ auto *MRI = Streamer.getContext().getRegisterInfo();
+
+ switch (Instr.getOperation()) {
+ case MCCFIInstruction::OpRegister: {
+ unsigned Reg1 = Instr.getRegister();
+ unsigned Reg2 = Instr.getRegister2();
+ if (!IsEH) {
+ Reg1 = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg1, true), false);
+ Reg2 = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg2, true), false);
+ }
+ Streamer.EmitIntValue(dwarf::DW_CFA_register, 1);
+ Streamer.EmitULEB128IntValue(Reg1);
+ Streamer.EmitULEB128IntValue(Reg2);
+ return;
+ }
+ case MCCFIInstruction::OpWindowSave: {
+ Streamer.EmitIntValue(dwarf::DW_CFA_GNU_window_save, 1);
+ return;
+ }
+ case MCCFIInstruction::OpUndefined: {
+ unsigned Reg = Instr.getRegister();
+ Streamer.EmitIntValue(dwarf::DW_CFA_undefined, 1);
+ Streamer.EmitULEB128IntValue(Reg);
+ return;
+ }
+ case MCCFIInstruction::OpAdjustCfaOffset:
+ case MCCFIInstruction::OpDefCfaOffset: {
+ const bool IsRelative =
+ Instr.getOperation() == MCCFIInstruction::OpAdjustCfaOffset;
+
+ Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
+
+ if (IsRelative)
+ CFAOffset += Instr.getOffset();
+ else
+ CFAOffset = -Instr.getOffset();
+
+ Streamer.EmitULEB128IntValue(CFAOffset);
+
+ return;
+ }
+ case MCCFIInstruction::OpDefCfa: {
+ unsigned Reg = Instr.getRegister();
+ if (!IsEH)
+ Reg = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg, true), false);
+ Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
+ Streamer.EmitULEB128IntValue(Reg);
+ CFAOffset = -Instr.getOffset();
+ Streamer.EmitULEB128IntValue(CFAOffset);
+
+ return;
+ }
+
+ case MCCFIInstruction::OpDefCfaRegister: {
+ unsigned Reg = Instr.getRegister();
+ if (!IsEH)
+ Reg = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg, true), false);
+ Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
+ Streamer.EmitULEB128IntValue(Reg);
+
+ return;
+ }
+
+ case MCCFIInstruction::OpOffset:
+ case MCCFIInstruction::OpRelOffset: {
+ const bool IsRelative =
+ Instr.getOperation() == MCCFIInstruction::OpRelOffset;
+
+ unsigned Reg = Instr.getRegister();
+ if (!IsEH)
+ Reg = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg, true), false);
+
+ int Offset = Instr.getOffset();
+ if (IsRelative)
+ Offset -= CFAOffset;
+ Offset = Offset / dataAlignmentFactor;
+
+ if (Offset < 0) {
+ Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended_sf, 1);
+ Streamer.EmitULEB128IntValue(Reg);
+ Streamer.EmitSLEB128IntValue(Offset);
+ } else if (Reg < 64) {
+ Streamer.EmitIntValue(dwarf::DW_CFA_offset + Reg, 1);
+ Streamer.EmitULEB128IntValue(Offset);
+ } else {
+ Streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
+ Streamer.EmitULEB128IntValue(Reg);
+ Streamer.EmitULEB128IntValue(Offset);
+ }
+ return;
+ }
+ case MCCFIInstruction::OpRememberState:
+ Streamer.EmitIntValue(dwarf::DW_CFA_remember_state, 1);
+ return;
+ case MCCFIInstruction::OpRestoreState:
+ Streamer.EmitIntValue(dwarf::DW_CFA_restore_state, 1);
+ return;
+ case MCCFIInstruction::OpSameValue: {
+ unsigned Reg = Instr.getRegister();
+ Streamer.EmitIntValue(dwarf::DW_CFA_same_value, 1);
+ Streamer.EmitULEB128IntValue(Reg);
+ return;
+ }
+ case MCCFIInstruction::OpRestore: {
+ unsigned Reg = Instr.getRegister();
+ if (!IsEH)
+ Reg = MRI->getDwarfRegNum(MRI->getLLVMRegNum(Reg, true), false);
+ Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
+ return;
+ }
+ case MCCFIInstruction::OpGnuArgsSize: {
+ Streamer.EmitIntValue(dwarf::DW_CFA_GNU_args_size, 1);
+ Streamer.EmitULEB128IntValue(Instr.getOffset());
+ return;
+ }
+ case MCCFIInstruction::OpEscape:
+ Streamer.EmitBytes(Instr.getValues());
+ return;
+ }
+ llvm_unreachable("Unhandled case in switch");
+}
+
+/// Emit frame instructions to describe the layout of the frame.
+void FrameEmitterImpl::EmitCFIInstructions(ArrayRef<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) {
+ Streamer.EmitDwarfAdvanceFrameAddr(BaseLabel, ThisSym);
+ BaseLabel = ThisSym;
+ }
+ }
+
+ EmitCFIInstruction(Instr);
+ }
+}
+
+/// Emit the unwind information in a compact way.
+void FrameEmitterImpl::EmitCompactUnwind(const MCDwarfFrameInfo &Frame) {
+ MCContext &Context = Streamer.getContext();
+ const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
+
+ // 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;
+ if (!Encoding) return;
+ bool DwarfEHFrameOnly = (Encoding == MOFI->getCompactUnwindDwarfEHFrameOnly());
+
+ // The encoding needs to know we have an LSDA.
+ if (!DwarfEHFrameOnly && Frame.Lsda)
+ Encoding |= 0x40000000;
+
+ // Range Start
+ unsigned FDEEncoding = MOFI->getFDEEncoding();
+ unsigned Size = getSizeForEncoding(Streamer, FDEEncoding);
+ Streamer.EmitSymbolValue(Frame.Begin, Size);
+
+ // Range Length
+ const MCExpr *Range = MakeStartMinusEndExpr(Streamer, *Frame.Begin,
+ *Frame.End, 0);
+ emitAbsValue(Streamer, Range, 4);
+
+ // Compact Encoding
+ Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_udata4);
+ Streamer.EmitIntValue(Encoding, Size);
+
+ // Personality Function
+ Size = getSizeForEncoding(Streamer, dwarf::DW_EH_PE_absptr);
+ if (!DwarfEHFrameOnly && Frame.Personality)
+ Streamer.EmitSymbolValue(Frame.Personality, Size);
+ else
+ Streamer.EmitIntValue(0, Size); // No personality fn
+
+ // LSDA
+ Size = getSizeForEncoding(Streamer, Frame.LsdaEncoding);
+ if (!DwarfEHFrameOnly && Frame.Lsda)
+ Streamer.EmitSymbolValue(Frame.Lsda, Size);
+ else
+ Streamer.EmitIntValue(0, Size); // No LSDA
+}
+
+static unsigned getCIEVersion(bool IsEH, unsigned DwarfVersion) {
+ if (IsEH)
+ return 1;
+ switch (DwarfVersion) {
+ case 2:
+ return 1;
+ case 3:
+ return 3;
+ case 4:
+ case 5:
+ return 4;
+ }
+ llvm_unreachable("Unknown version");
+}
+
+const MCSymbol &FrameEmitterImpl::EmitCIE(const MCSymbol *personality,
+ unsigned personalityEncoding,
+ const MCSymbol *lsda,
+ bool IsSignalFrame,
+ unsigned lsdaEncoding,
+ bool IsSimple) {
+ MCContext &context = Streamer.getContext();
+ const MCRegisterInfo *MRI = context.getRegisterInfo();
+ const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
+
+ MCSymbol *sectionStart = context.createTempSymbol();
+ Streamer.EmitLabel(sectionStart);
+
+ MCSymbol *sectionEnd = context.createTempSymbol();
+
+ // Length
+ const MCExpr *Length =
+ MakeStartMinusEndExpr(Streamer, *sectionStart, *sectionEnd, 4);
+ emitAbsValue(Streamer, Length, 4);
+
+ // CIE ID
+ unsigned CIE_ID = IsEH ? 0 : -1;
+ Streamer.EmitIntValue(CIE_ID, 4);
+
+ // Version
+ uint8_t CIEVersion = getCIEVersion(IsEH, context.getDwarfVersion());
+ Streamer.EmitIntValue(CIEVersion, 1);
+
+ // Augmentation String
+ SmallString<8> Augmentation;
+ if (IsEH) {
+ Augmentation += "z";
+ if (personality)
+ Augmentation += "P";
+ if (lsda)
+ Augmentation += "L";
+ Augmentation += "R";
+ if (IsSignalFrame)
+ Augmentation += "S";
+ Streamer.EmitBytes(Augmentation);
+ }
+ Streamer.EmitIntValue(0, 1);
+
+ if (CIEVersion >= 4) {
+ // Address Size
+ Streamer.EmitIntValue(context.getAsmInfo()->getPointerSize(), 1);
+
+ // Segment Descriptor Size
+ Streamer.EmitIntValue(0, 1);
+ }
+
+ // Code Alignment Factor
+ Streamer.EmitULEB128IntValue(context.getAsmInfo()->getMinInstAlignment());
+
+ // Data Alignment Factor
+ Streamer.EmitSLEB128IntValue(getDataAlignmentFactor(Streamer));
+
+ // Return Address Register
+ if (CIEVersion == 1) {
+ assert(MRI->getRARegister() <= 255 &&
+ "DWARF 2 encodes return_address_register in one byte");
+ Streamer.EmitIntValue(MRI->getDwarfRegNum(MRI->getRARegister(), IsEH), 1);
+ } else {
+ Streamer.EmitULEB128IntValue(
+ MRI->getDwarfRegNum(MRI->getRARegister(), IsEH));
+ }
+
+ // 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;
+
+ Streamer.EmitULEB128IntValue(augmentationLength);
+
+ // Augmentation Data (optional)
+ if (personality) {
+ // Personality Encoding
+ emitEncodingByte(Streamer, personalityEncoding);
+ // Personality
+ EmitPersonality(Streamer, *personality, personalityEncoding);
+ }
+
+ if (lsda)
+ emitEncodingByte(Streamer, lsdaEncoding);
+
+ // Encoding of the FDE pointers
+ emitEncodingByte(Streamer, MOFI->getFDEEncoding());
+ }
+
+ // Initial Instructions
+
+ const MCAsmInfo *MAI = context.getAsmInfo();
+ if (!IsSimple) {
+ const std::vector<MCCFIInstruction> &Instructions =
+ MAI->getInitialFrameState();
+ EmitCFIInstructions(Instructions, nullptr);
+ }
+
+ InitialCFAOffset = CFAOffset;
+
+ // Padding
+ Streamer.EmitValueToAlignment(IsEH ? 4 : MAI->getPointerSize());
+
+ Streamer.EmitLabel(sectionEnd);
+ return *sectionStart;
+}
+
+void FrameEmitterImpl::EmitFDE(const MCSymbol &cieStart,
+ const MCDwarfFrameInfo &frame,
+ bool LastInSection,
+ const MCSymbol &SectionStart) {
+ MCContext &context = Streamer.getContext();
+ MCSymbol *fdeStart = context.createTempSymbol();
+ MCSymbol *fdeEnd = context.createTempSymbol();
+ const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
+
+ CFAOffset = InitialCFAOffset;
+
+ // Length
+ const MCExpr *Length = MakeStartMinusEndExpr(Streamer, *fdeStart, *fdeEnd, 0);
+ emitAbsValue(Streamer, Length, 4);
+
+ Streamer.EmitLabel(fdeStart);
+
+ // CIE Pointer
+ const MCAsmInfo *asmInfo = context.getAsmInfo();
+ if (IsEH) {
+ const MCExpr *offset =
+ MakeStartMinusEndExpr(Streamer, cieStart, *fdeStart, 0);
+ emitAbsValue(Streamer, offset, 4);
+ } else if (!asmInfo->doesDwarfUseRelocationsAcrossSections()) {
+ const MCExpr *offset =
+ MakeStartMinusEndExpr(Streamer, SectionStart, cieStart, 0);
+ emitAbsValue(Streamer, offset, 4);
+ } else {
+ Streamer.EmitSymbolValue(&cieStart, 4);
+ }
+
+ // PC Begin
+ unsigned PCEncoding =
+ IsEH ? MOFI->getFDEEncoding() : (unsigned)dwarf::DW_EH_PE_absptr;
+ unsigned PCSize = getSizeForEncoding(Streamer, PCEncoding);
+ emitFDESymbol(Streamer, *frame.Begin, PCEncoding, IsEH);
+
+ // PC Range
+ const MCExpr *Range =
+ MakeStartMinusEndExpr(Streamer, *frame.Begin, *frame.End, 0);
+ emitAbsValue(Streamer, Range, PCSize);
+
+ if (IsEH) {
+ // Augmentation Data Length
+ unsigned augmentationLength = 0;
+
+ if (frame.Lsda)
+ augmentationLength += getSizeForEncoding(Streamer, frame.LsdaEncoding);
+
+ Streamer.EmitULEB128IntValue(augmentationLength);
+
+ // Augmentation Data
+ if (frame.Lsda)
+ emitFDESymbol(Streamer, *frame.Lsda, frame.LsdaEncoding, true);
+ }
+
+ // Call Frame Instructions
+ EmitCFIInstructions(frame.Instructions, frame.Begin);
+
+ // Padding
+ // The size of a .eh_frame section has to be a multiple of the alignment
+ // since a null CIE is interpreted as the end. Old systems overaligned
+ // .eh_frame, so we do too and account for it in the last FDE.
+ unsigned Align = LastInSection ? asmInfo->getPointerSize() : PCSize;
+ Streamer.EmitValueToAlignment(Align);
+
+ Streamer.EmitLabel(fdeEnd);
+}
+
+namespace {
+struct CIEKey {
+ static const CIEKey getEmptyKey() {
+ return CIEKey(nullptr, 0, -1, false, false);
+ }
+ static const CIEKey getTombstoneKey() {
+ return CIEKey(nullptr, -1, 0, false, false);
+ }
+
+ CIEKey(const MCSymbol *Personality, unsigned PersonalityEncoding,
+ unsigned LsdaEncoding, bool IsSignalFrame, bool IsSimple)
+ : Personality(Personality), PersonalityEncoding(PersonalityEncoding),
+ LsdaEncoding(LsdaEncoding), IsSignalFrame(IsSignalFrame),
+ IsSimple(IsSimple) {}
+ const MCSymbol *Personality;
+ unsigned PersonalityEncoding;
+ unsigned LsdaEncoding;
+ bool IsSignalFrame;
+ bool IsSimple;
+};
+} // anonymous namespace
+
+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, Key.IsSimple));
+ }
+ 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 &&
+ LHS.IsSimple == RHS.IsSimple;
+ }
+};
+} // namespace llvm
+
+void MCDwarfFrameEmitter::Emit(MCObjectStreamer &Streamer, MCAsmBackend *MAB,
+ bool IsEH) {
+ Streamer.generateCompactUnwindEncodings(MAB);
+
+ MCContext &Context = Streamer.getContext();
+ const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
+ FrameEmitterImpl Emitter(IsEH, Streamer);
+ ArrayRef<MCDwarfFrameInfo> FrameArray = Streamer.getDwarfFrameInfos();
+
+ // Emit the compact unwind info if available.
+ bool NeedsEHFrameSection = !MOFI->getSupportsCompactUnwindWithoutEHFrame();
+ if (IsEH && MOFI->getCompactUnwindSection()) {
+ bool SectionEmitted = false;
+ for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
+ const MCDwarfFrameInfo &Frame = FrameArray[i];
+ if (Frame.CompactUnwindEncoding == 0) continue;
+ if (!SectionEmitted) {
+ Streamer.SwitchSection(MOFI->getCompactUnwindSection());
+ Streamer.EmitValueToAlignment(Context.getAsmInfo()->getPointerSize());
+ SectionEmitted = true;
+ }
+ NeedsEHFrameSection |=
+ Frame.CompactUnwindEncoding ==
+ MOFI->getCompactUnwindDwarfEHFrameOnly();
+ Emitter.EmitCompactUnwind(Frame);
+ }
+ }
+
+ if (!NeedsEHFrameSection) return;
+
+ MCSection &Section =
+ IsEH ? *const_cast<MCObjectFileInfo *>(MOFI)->getEHFrameSection()
+ : *MOFI->getDwarfFrameSection();
+
+ Streamer.SwitchSection(&Section);
+ MCSymbol *SectionStart = Context.createTempSymbol();
+ Streamer.EmitLabel(SectionStart);
+
+ DenseMap<CIEKey, const MCSymbol *> CIEStarts;
+
+ const MCSymbol *DummyDebugKey = nullptr;
+ bool CanOmitDwarf = MOFI->getOmitDwarfIfHaveCompactUnwind();
+ for (auto I = FrameArray.begin(), E = FrameArray.end(); I != E;) {
+ const MCDwarfFrameInfo &Frame = *I;
+ ++I;
+ if (CanOmitDwarf && Frame.CompactUnwindEncoding !=
+ MOFI->getCompactUnwindDwarfEHFrameOnly())
+ // Don't generate an EH frame if we don't need one. I.e., it's taken care
+ // of by the compact unwind encoding.
+ continue;
+
+ CIEKey Key(Frame.Personality, Frame.PersonalityEncoding,
+ Frame.LsdaEncoding, Frame.IsSignalFrame, Frame.IsSimple);
+ const MCSymbol *&CIEStart = IsEH ? CIEStarts[Key] : DummyDebugKey;
+ if (!CIEStart)
+ CIEStart = &Emitter.EmitCIE(Frame.Personality, Frame.PersonalityEncoding,
+ Frame.Lsda, Frame.IsSignalFrame,
+ Frame.LsdaEncoding, Frame.IsSimple);
+
+ Emitter.EmitFDE(*CIEStart, Frame, I == E, *SectionStart);
+ }
+}
+
+void MCDwarfFrameEmitter::EmitAdvanceLoc(MCObjectStreamer &Streamer,
+ uint64_t AddrDelta) {
+ MCContext &Context = Streamer.getContext();
+ SmallString<256> Tmp;
+ raw_svector_ostream OS(Tmp);
+ MCDwarfFrameEmitter::EncodeAdvanceLoc(Context, AddrDelta, OS);
+ Streamer.EmitBytes(OS.str());
+}
+
+void MCDwarfFrameEmitter::EncodeAdvanceLoc(MCContext &Context,
+ uint64_t AddrDelta,
+ raw_ostream &OS) {
+ // Scale the address delta by the minimum instruction length.
+ AddrDelta = ScaleAddrDelta(Context, AddrDelta);
+
+ 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)) {
+ OS << uint8_t(dwarf::DW_CFA_advance_loc2);
+ if (Context.getAsmInfo()->isLittleEndian())
+ support::endian::Writer<support::little>(OS).write<uint16_t>(AddrDelta);
+ else
+ support::endian::Writer<support::big>(OS).write<uint16_t>(AddrDelta);
+ } else {
+ assert(isUInt<32>(AddrDelta));
+ OS << uint8_t(dwarf::DW_CFA_advance_loc4);
+ if (Context.getAsmInfo()->isLittleEndian())
+ support::endian::Writer<support::little>(OS).write<uint32_t>(AddrDelta);
+ else
+ support::endian::Writer<support::big>(OS).write<uint32_t>(AddrDelta);
+ }
+}
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