mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-26 07:29:55 +00:00
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216086 91177308-0d34-0410-b5e6-96231b3b80d8
1582 lines
56 KiB
C++
1582 lines
56 KiB
C++
//===- lib/MC/MCDwarf.cpp - MCDwarf implementation ------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/MC/MCDwarf.h"
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#include "llvm/ADT/Hashing.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/Config/config.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCObjectFileInfo.h"
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#include "llvm/MC/MCObjectStreamer.h"
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#include "llvm/MC/MCRegisterInfo.h"
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#include "llvm/MC/MCSection.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/LEB128.h"
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#include "llvm/Support/Path.h"
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#include "llvm/Support/SourceMgr.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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// Given a special op, return the address skip amount (in units of
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// DWARF2_LINE_MIN_INSN_LENGTH.
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#define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
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// The maximum address skip amount that can be encoded with a special op.
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#define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
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// First special line opcode - leave room for the standard opcodes.
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// Note: If you want to change this, you'll have to update the
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// "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
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#define DWARF2_LINE_OPCODE_BASE 13
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// Minimum line offset in a special line info. opcode. This value
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// was chosen to give a reasonable range of values.
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#define DWARF2_LINE_BASE -5
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// Range of line offsets in a special line info. opcode.
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#define DWARF2_LINE_RANGE 14
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static inline uint64_t ScaleAddrDelta(MCContext &Context, uint64_t AddrDelta) {
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unsigned MinInsnLength = Context.getAsmInfo()->getMinInstAlignment();
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if (MinInsnLength == 1)
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return AddrDelta;
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if (AddrDelta % MinInsnLength != 0) {
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// TODO: report this error, but really only once.
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;
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}
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return AddrDelta / MinInsnLength;
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}
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//
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// This is called when an instruction is assembled into the specified section
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// and if there is information from the last .loc directive that has yet to have
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// a line entry made for it is made.
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//
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void MCLineEntry::Make(MCObjectStreamer *MCOS, const MCSection *Section) {
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if (!MCOS->getContext().getDwarfLocSeen())
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return;
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// Create a symbol at in the current section for use in the line entry.
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MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
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// Set the value of the symbol to use for the MCLineEntry.
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MCOS->EmitLabel(LineSym);
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// Get the current .loc info saved in the context.
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const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
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// Create a (local) line entry with the symbol and the current .loc info.
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MCLineEntry LineEntry(LineSym, DwarfLoc);
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// clear DwarfLocSeen saying the current .loc info is now used.
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MCOS->getContext().ClearDwarfLocSeen();
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// Add the line entry to this section's entries.
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MCOS->getContext()
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.getMCDwarfLineTable(MCOS->getContext().getDwarfCompileUnitID())
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.getMCLineSections()
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.addLineEntry(LineEntry, Section);
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}
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//
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// This helper routine returns an expression of End - Start + IntVal .
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//
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static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
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const MCSymbol &Start,
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const MCSymbol &End,
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int IntVal) {
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MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
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const MCExpr *Res =
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MCSymbolRefExpr::Create(&End, Variant, MCOS.getContext());
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const MCExpr *RHS =
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MCSymbolRefExpr::Create(&Start, Variant, MCOS.getContext());
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const MCExpr *Res1 =
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MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS.getContext());
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const MCExpr *Res2 =
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MCConstantExpr::Create(IntVal, MCOS.getContext());
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const MCExpr *Res3 =
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MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS.getContext());
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return Res3;
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}
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//
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// This emits the Dwarf line table for the specified section from the entries
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// in the LineSection.
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//
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static inline void
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EmitDwarfLineTable(MCObjectStreamer *MCOS, const MCSection *Section,
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const MCLineSection::MCLineEntryCollection &LineEntries) {
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unsigned FileNum = 1;
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unsigned LastLine = 1;
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unsigned Column = 0;
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unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
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unsigned Isa = 0;
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unsigned Discriminator = 0;
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MCSymbol *LastLabel = nullptr;
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// Loop through each MCLineEntry and encode the dwarf line number table.
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for (auto it = LineEntries.begin(),
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ie = LineEntries.end();
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it != ie; ++it) {
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if (FileNum != it->getFileNum()) {
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FileNum = it->getFileNum();
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MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
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MCOS->EmitULEB128IntValue(FileNum);
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}
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if (Column != it->getColumn()) {
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Column = it->getColumn();
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MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
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MCOS->EmitULEB128IntValue(Column);
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}
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if (Discriminator != it->getDiscriminator()) {
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Discriminator = it->getDiscriminator();
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unsigned Size = getULEB128Size(Discriminator);
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MCOS->EmitIntValue(dwarf::DW_LNS_extended_op, 1);
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MCOS->EmitULEB128IntValue(Size + 1);
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MCOS->EmitIntValue(dwarf::DW_LNE_set_discriminator, 1);
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MCOS->EmitULEB128IntValue(Discriminator);
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}
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if (Isa != it->getIsa()) {
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Isa = it->getIsa();
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MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
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MCOS->EmitULEB128IntValue(Isa);
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}
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if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
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Flags = it->getFlags();
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MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
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}
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if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
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MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
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if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
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MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
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if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
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MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
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int64_t LineDelta = static_cast<int64_t>(it->getLine()) - LastLine;
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MCSymbol *Label = it->getLabel();
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// At this point we want to emit/create the sequence to encode the delta in
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// line numbers and the increment of the address from the previous Label
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// and the current Label.
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const MCAsmInfo *asmInfo = MCOS->getContext().getAsmInfo();
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MCOS->EmitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
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asmInfo->getPointerSize());
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LastLine = it->getLine();
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LastLabel = Label;
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}
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// Emit a DW_LNE_end_sequence for the end of the section.
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// Using the pointer Section create a temporary label at the end of the
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// section and use that and the LastLabel to compute the address delta
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// and use INT64_MAX as the line delta which is the signal that this is
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// actually a DW_LNE_end_sequence.
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// Switch to the section to be able to create a symbol at its end.
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// TODO: keep track of the last subsection so that this symbol appears in the
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// correct place.
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MCOS->SwitchSection(Section);
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MCContext &context = MCOS->getContext();
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// Create a symbol at the end of the section.
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MCSymbol *SectionEnd = context.CreateTempSymbol();
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// Set the value of the symbol, as we are at the end of the section.
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MCOS->EmitLabel(SectionEnd);
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// Switch back the dwarf line section.
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MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
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const MCAsmInfo *asmInfo = MCOS->getContext().getAsmInfo();
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MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd,
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asmInfo->getPointerSize());
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}
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//
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// This emits the Dwarf file and the line tables.
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//
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void MCDwarfLineTable::Emit(MCObjectStreamer *MCOS) {
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MCContext &context = MCOS->getContext();
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auto &LineTables = context.getMCDwarfLineTables();
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// Bail out early so we don't switch to the debug_line section needlessly and
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// in doing so create an unnecessary (if empty) section.
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if (LineTables.empty())
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return;
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// Switch to the section where the table will be emitted into.
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MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
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// Handle the rest of the Compile Units.
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for (const auto &CUIDTablePair : LineTables)
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CUIDTablePair.second.EmitCU(MCOS);
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}
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void MCDwarfDwoLineTable::Emit(MCStreamer &MCOS) const {
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MCOS.EmitLabel(Header.Emit(&MCOS, None).second);
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}
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std::pair<MCSymbol *, MCSymbol *> MCDwarfLineTableHeader::Emit(MCStreamer *MCOS) const {
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static const char StandardOpcodeLengths[] = {
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0, // length of DW_LNS_copy
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1, // length of DW_LNS_advance_pc
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1, // length of DW_LNS_advance_line
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1, // length of DW_LNS_set_file
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1, // length of DW_LNS_set_column
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0, // length of DW_LNS_negate_stmt
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0, // length of DW_LNS_set_basic_block
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0, // length of DW_LNS_const_add_pc
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1, // length of DW_LNS_fixed_advance_pc
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0, // length of DW_LNS_set_prologue_end
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0, // length of DW_LNS_set_epilogue_begin
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1 // DW_LNS_set_isa
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};
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assert(array_lengthof(StandardOpcodeLengths) == (DWARF2_LINE_OPCODE_BASE - 1));
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return Emit(MCOS, StandardOpcodeLengths);
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}
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static const MCExpr *forceExpAbs(MCStreamer &OS, const MCExpr* Expr) {
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MCContext &Context = OS.getContext();
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assert(!isa<MCSymbolRefExpr>(Expr));
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if (Context.getAsmInfo()->hasAggressiveSymbolFolding())
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return Expr;
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MCSymbol *ABS = Context.CreateTempSymbol();
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OS.EmitAssignment(ABS, Expr);
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return MCSymbolRefExpr::Create(ABS, Context);
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}
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static void emitAbsValue(MCStreamer &OS, const MCExpr *Value, unsigned Size) {
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const MCExpr *ABS = forceExpAbs(OS, Value);
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OS.EmitValue(ABS, Size);
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}
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std::pair<MCSymbol *, MCSymbol *>
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MCDwarfLineTableHeader::Emit(MCStreamer *MCOS,
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ArrayRef<char> StandardOpcodeLengths) const {
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MCContext &context = MCOS->getContext();
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// Create a symbol at the beginning of the line table.
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MCSymbol *LineStartSym = Label;
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if (!LineStartSym)
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LineStartSym = context.CreateTempSymbol();
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// Set the value of the symbol, as we are at the start of the line table.
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MCOS->EmitLabel(LineStartSym);
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// Create a symbol for the end of the section (to be set when we get there).
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MCSymbol *LineEndSym = context.CreateTempSymbol();
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// The first 4 bytes is the total length of the information for this
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// compilation unit (not including these 4 bytes for the length).
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emitAbsValue(*MCOS,
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MakeStartMinusEndExpr(*MCOS, *LineStartSym, *LineEndSym, 4), 4);
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// Next 2 bytes is the Version, which is Dwarf 2.
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MCOS->EmitIntValue(2, 2);
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// Create a symbol for the end of the prologue (to be set when we get there).
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MCSymbol *ProEndSym = context.CreateTempSymbol(); // Lprologue_end
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// Length of the prologue, is the next 4 bytes. Which is the start of the
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// section to the end of the prologue. Not including the 4 bytes for the
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// total length, the 2 bytes for the version, and these 4 bytes for the
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// length of the prologue.
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emitAbsValue(
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*MCOS,
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MakeStartMinusEndExpr(*MCOS, *LineStartSym, *ProEndSym, (4 + 2 + 4)), 4);
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// Parameters of the state machine, are next.
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MCOS->EmitIntValue(context.getAsmInfo()->getMinInstAlignment(), 1);
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MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
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MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
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MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
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MCOS->EmitIntValue(StandardOpcodeLengths.size() + 1, 1);
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// Standard opcode lengths
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for (char Length : StandardOpcodeLengths)
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MCOS->EmitIntValue(Length, 1);
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// Put out the directory and file tables.
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// First the directory table.
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for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
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MCOS->EmitBytes(MCDwarfDirs[i]); // the DirectoryName
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MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
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}
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MCOS->EmitIntValue(0, 1); // Terminate the directory list
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// Second the file table.
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for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
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assert(!MCDwarfFiles[i].Name.empty());
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MCOS->EmitBytes(MCDwarfFiles[i].Name); // FileName
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MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
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// the Directory num
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MCOS->EmitULEB128IntValue(MCDwarfFiles[i].DirIndex);
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MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
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MCOS->EmitIntValue(0, 1); // filesize (always 0)
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}
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MCOS->EmitIntValue(0, 1); // Terminate the file list
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// This is the end of the prologue, so set the value of the symbol at the
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// end of the prologue (that was used in a previous expression).
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MCOS->EmitLabel(ProEndSym);
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return std::make_pair(LineStartSym, LineEndSym);
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}
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void MCDwarfLineTable::EmitCU(MCObjectStreamer *MCOS) const {
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MCSymbol *LineEndSym = Header.Emit(MCOS).second;
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// Put out the line tables.
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for (const auto &LineSec : MCLineSections.getMCLineEntries())
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EmitDwarfLineTable(MCOS, LineSec.first, LineSec.second);
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if (MCOS->getContext().getAsmInfo()->getLinkerRequiresNonEmptyDwarfLines() &&
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MCLineSections.getMCLineEntries().empty()) {
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// The darwin9 linker has a bug (see PR8715). For for 32-bit architectures
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// it requires:
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// total_length >= prologue_length + 10
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// We are 4 bytes short, since we have total_length = 51 and
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// prologue_length = 45
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// The regular end_sequence should be sufficient.
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MCDwarfLineAddr::Emit(MCOS, INT64_MAX, 0);
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}
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// This is the end of the section, so set the value of the symbol at the end
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// of this section (that was used in a previous expression).
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MCOS->EmitLabel(LineEndSym);
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}
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unsigned MCDwarfLineTable::getFile(StringRef &Directory, StringRef &FileName,
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unsigned FileNumber) {
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return Header.getFile(Directory, FileName, FileNumber);
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}
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unsigned MCDwarfLineTableHeader::getFile(StringRef &Directory,
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StringRef &FileName,
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unsigned FileNumber) {
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if (Directory == CompilationDir)
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Directory = "";
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if (FileName.empty()) {
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FileName = "<stdin>";
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Directory = "";
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}
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assert(!FileName.empty());
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if (FileNumber == 0) {
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FileNumber = SourceIdMap.size() + 1;
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assert((MCDwarfFiles.empty() || FileNumber == MCDwarfFiles.size()) &&
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"Don't mix autonumbered and explicit numbered line table usage");
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StringMapEntry<unsigned> &Ent = SourceIdMap.GetOrCreateValue(
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(Directory + Twine('\0') + FileName).str(), FileNumber);
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if (Ent.getValue() != FileNumber)
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return Ent.getValue();
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}
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// Make space for this FileNumber in the MCDwarfFiles vector if needed.
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MCDwarfFiles.resize(FileNumber + 1);
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// Get the new MCDwarfFile slot for this FileNumber.
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MCDwarfFile &File = MCDwarfFiles[FileNumber];
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// It is an error to use see the same number more than once.
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if (!File.Name.empty())
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return 0;
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if (Directory.empty()) {
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// Separate the directory part from the basename of the FileName.
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StringRef tFileName = sys::path::filename(FileName);
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if (!tFileName.empty()) {
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Directory = sys::path::parent_path(FileName);
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if (!Directory.empty())
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FileName = tFileName;
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}
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}
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// Find or make an entry in the MCDwarfDirs vector for this Directory.
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// Capture directory name.
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unsigned DirIndex;
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if (Directory.empty()) {
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// For FileNames with no directories a DirIndex of 0 is used.
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DirIndex = 0;
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} else {
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DirIndex = 0;
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for (unsigned End = MCDwarfDirs.size(); DirIndex < End; DirIndex++) {
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if (Directory == MCDwarfDirs[DirIndex])
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break;
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}
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if (DirIndex >= MCDwarfDirs.size())
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MCDwarfDirs.push_back(Directory);
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// The DirIndex is one based, as DirIndex of 0 is used for FileNames with
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// no directories. MCDwarfDirs[] is unlike MCDwarfFiles[] in that the
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// directory names are stored at MCDwarfDirs[DirIndex-1] where FileNames
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// are stored at MCDwarfFiles[FileNumber].Name .
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DirIndex++;
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}
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File.Name = FileName;
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File.DirIndex = DirIndex;
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// return the allocated FileNumber.
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return FileNumber;
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}
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/// Utility function to emit the encoding to a streamer.
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void MCDwarfLineAddr::Emit(MCStreamer *MCOS, int64_t LineDelta,
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uint64_t AddrDelta) {
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MCContext &Context = MCOS->getContext();
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SmallString<256> Tmp;
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raw_svector_ostream OS(Tmp);
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MCDwarfLineAddr::Encode(Context, LineDelta, AddrDelta, OS);
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MCOS->EmitBytes(OS.str());
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}
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|
|
/// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
|
|
void MCDwarfLineAddr::Encode(MCContext &Context, 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(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 == 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);
|
|
}
|
|
|
|
// 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);
|
|
if (MCOS->getContext().getGenDwarfSectionSyms().size() > 1) {
|
|
EmitAbbrev(MCOS, dwarf::DW_AT_ranges, 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);
|
|
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 (const auto &sec : Sections) {
|
|
MCSymbol *StartSymbol = sec.second.first;
|
|
MCSymbol *EndSymbol = sec.second.second;
|
|
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);
|
|
} 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->second.first;
|
|
MCSymbol *EndSymbol = TextSection->second.second;
|
|
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 (const auto sec : Sections) {
|
|
|
|
MCSymbol *StartSymbol = sec.second.first;
|
|
MCSymbol *EndSymbol = sec.second.second;
|
|
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 = NULL;
|
|
|
|
// 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 need to use the .debug_ranges section if we have multiple
|
|
// code sections.
|
|
const bool UseRangesSection =
|
|
MCOS->getContext().getGenDwarfSectionSyms().size() > 1;
|
|
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;
|
|
bool IsEH;
|
|
const MCSymbol *SectionStart;
|
|
public:
|
|
FrameEmitterImpl(bool isEH)
|
|
: CFAOffset(0), IsEH(isEH), SectionStart(nullptr) {}
|
|
|
|
void setSectionStart(const MCSymbol *Label) { SectionStart = Label; }
|
|
|
|
/// Emit the unwind information in a compact way.
|
|
void EmitCompactUnwind(MCObjectStreamer &streamer,
|
|
const MCDwarfFrameInfo &frame);
|
|
|
|
const MCSymbol &EmitCIE(MCObjectStreamer &streamer,
|
|
const MCSymbol *personality,
|
|
unsigned personalityEncoding,
|
|
const MCSymbol *lsda,
|
|
bool IsSignalFrame,
|
|
unsigned lsdaEncoding,
|
|
bool IsSimple);
|
|
MCSymbol *EmitFDE(MCObjectStreamer &streamer,
|
|
const MCSymbol &cieStart,
|
|
const MCDwarfFrameInfo &frame);
|
|
void EmitCFIInstructions(MCObjectStreamer &streamer,
|
|
ArrayRef<MCCFIInstruction> Instrs,
|
|
MCSymbol *BaseLabel);
|
|
void EmitCFIInstruction(MCObjectStreamer &Streamer,
|
|
const MCCFIInstruction &Instr);
|
|
};
|
|
|
|
} // end anonymous namespace
|
|
|
|
static void emitEncodingByte(MCObjectStreamer &Streamer, unsigned Encoding) {
|
|
Streamer.EmitIntValue(Encoding, 1);
|
|
}
|
|
|
|
void FrameEmitterImpl::EmitCFIInstruction(MCObjectStreamer &Streamer,
|
|
const MCCFIInstruction &Instr) {
|
|
int dataAlignmentFactor = getDataAlignmentFactor(Streamer);
|
|
|
|
switch (Instr.getOperation()) {
|
|
case MCCFIInstruction::OpRegister: {
|
|
unsigned Reg1 = Instr.getRegister();
|
|
unsigned Reg2 = Instr.getRegister2();
|
|
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: {
|
|
Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
|
|
Streamer.EmitULEB128IntValue(Instr.getRegister());
|
|
CFAOffset = -Instr.getOffset();
|
|
Streamer.EmitULEB128IntValue(CFAOffset);
|
|
|
|
return;
|
|
}
|
|
|
|
case MCCFIInstruction::OpDefCfaRegister: {
|
|
Streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
|
|
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) {
|
|
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();
|
|
Streamer.EmitIntValue(dwarf::DW_CFA_restore | Reg, 1);
|
|
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(MCObjectStreamer &streamer,
|
|
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(streamer, Instr);
|
|
}
|
|
}
|
|
|
|
/// Emit the unwind information in a compact way.
|
|
void FrameEmitterImpl::EmitCompactUnwind(MCObjectStreamer &Streamer,
|
|
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
|
|
}
|
|
|
|
const MCSymbol &FrameEmitterImpl::EmitCIE(MCObjectStreamer &streamer,
|
|
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
|
|
// For DWARF2, we use CIE version 1
|
|
// For DWARF3+, we use CIE version 3
|
|
uint8_t CIEVersion = context.getDwarfVersion() <= 2 ? 1 : 3;
|
|
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.str());
|
|
}
|
|
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(), true), 1);
|
|
} else {
|
|
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;
|
|
|
|
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(streamer, Instructions, nullptr);
|
|
}
|
|
|
|
// Padding
|
|
streamer.EmitValueToAlignment(IsEH ? 4 : MAI->getPointerSize());
|
|
|
|
streamer.EmitLabel(sectionEnd);
|
|
return *sectionStart;
|
|
}
|
|
|
|
MCSymbol *FrameEmitterImpl::EmitFDE(MCObjectStreamer &streamer,
|
|
const MCSymbol &cieStart,
|
|
const MCDwarfFrameInfo &frame) {
|
|
MCContext &context = streamer.getContext();
|
|
MCSymbol *fdeStart = context.CreateTempSymbol();
|
|
MCSymbol *fdeEnd = context.CreateTempSymbol();
|
|
const MCObjectFileInfo *MOFI = context.getObjectFileInfo();
|
|
|
|
// 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(streamer, frame.Instructions, frame.Begin);
|
|
|
|
// Padding
|
|
streamer.EmitValueToAlignment(PCSize);
|
|
|
|
return 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;
|
|
};
|
|
}
|
|
|
|
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;
|
|
}
|
|
};
|
|
}
|
|
|
|
void MCDwarfFrameEmitter::Emit(MCObjectStreamer &Streamer, MCAsmBackend *MAB,
|
|
bool IsEH) {
|
|
Streamer.generateCompactUnwindEncodings(MAB);
|
|
|
|
MCContext &Context = Streamer.getContext();
|
|
const MCObjectFileInfo *MOFI = Context.getObjectFileInfo();
|
|
FrameEmitterImpl Emitter(IsEH);
|
|
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(Streamer, Frame);
|
|
}
|
|
}
|
|
|
|
if (!NeedsEHFrameSection) return;
|
|
|
|
const MCSection &Section =
|
|
IsEH ? *const_cast<MCObjectFileInfo*>(MOFI)->getEHFrameSection() :
|
|
*MOFI->getDwarfFrameSection();
|
|
|
|
Streamer.SwitchSection(&Section);
|
|
MCSymbol *SectionStart = Context.CreateTempSymbol();
|
|
Streamer.EmitLabel(SectionStart);
|
|
Emitter.setSectionStart(SectionStart);
|
|
|
|
MCSymbol *FDEEnd = nullptr;
|
|
DenseMap<CIEKey, const MCSymbol *> CIEStarts;
|
|
|
|
const MCSymbol *DummyDebugKey = nullptr;
|
|
NeedsEHFrameSection = !MOFI->getSupportsCompactUnwindWithoutEHFrame();
|
|
for (unsigned i = 0, n = FrameArray.size(); i < n; ++i) {
|
|
const MCDwarfFrameInfo &Frame = FrameArray[i];
|
|
|
|
// Emit the label from the previous iteration
|
|
if (FDEEnd) {
|
|
Streamer.EmitLabel(FDEEnd);
|
|
FDEEnd = nullptr;
|
|
}
|
|
|
|
if (!NeedsEHFrameSection && 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(Streamer, Frame.Personality,
|
|
Frame.PersonalityEncoding, Frame.Lsda,
|
|
Frame.IsSignalFrame,
|
|
Frame.LsdaEncoding,
|
|
Frame.IsSimple);
|
|
|
|
FDEEnd = Emitter.EmitFDE(Streamer, *CIEStart, Frame);
|
|
}
|
|
|
|
Streamer.EmitValueToAlignment(Context.getAsmInfo()->getPointerSize());
|
|
if (FDEEnd)
|
|
Streamer.EmitLabel(FDEEnd);
|
|
}
|
|
|
|
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)) {
|
|
// 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);
|
|
|
|
}
|
|
}
|