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Initial support for the cfi directives. This is just enough to get

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f:
        .cfi_startproc
        nop
        .cfi_endproc

assembled (on ELF).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121434 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rafael Espindola
2010-12-09 23:48:29 +00:00
parent 29012319cd
commit 1c952b9cc9
32 changed files with 550 additions and 176 deletions
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210
lib/MC/MCDwarf.cpp
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@ -19,6 +19,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetAsmBackend.h"
#include "llvm/Target/TargetAsmInfo.h"
using namespace llvm;
// Given a special op, return the address skip amount (in units of
@ -125,8 +126,7 @@ static inline const MCExpr *MakeStartMinusEndExpr(const MCStreamer &MCOS,
//
static inline void EmitDwarfLineTable(MCStreamer *MCOS,
const MCSection *Section,
const MCLineSection *LineSection,
const MCSection *DwarfLineSection) {
const MCLineSection *LineSection) {
unsigned FileNum = 1;
unsigned LastLine = 1;
unsigned Column = 0;
@ -185,13 +185,15 @@ static inline void EmitDwarfLineTable(MCStreamer *MCOS,
// Switch to the section to be able to create a symbol at its end.
MCOS->SwitchSection(Section);
MCContext &context = MCOS->getContext();
// Create a symbol at the end of the section.
MCSymbol *SectionEnd = MCOS->getContext().CreateTempSymbol();
MCSymbol *SectionEnd = context.CreateTempSymbol();
// Set the value of the symbol, as we are at the end of the section.
MCOS->EmitLabel(SectionEnd);
// Switch back the the dwarf line section.
MCOS->SwitchSection(DwarfLineSection);
MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
MCOS->EmitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, SectionEnd);
}
@ -199,18 +201,18 @@ static inline void EmitDwarfLineTable(MCStreamer *MCOS,
//
// This emits the Dwarf file and the line tables.
//
void MCDwarfFileTable::Emit(MCStreamer *MCOS,
const MCSection *DwarfLineSection) {
void MCDwarfFileTable::Emit(MCStreamer *MCOS) {
MCContext &context = MCOS->getContext();
// Switch to the section where the table will be emitted into.
MCOS->SwitchSection(DwarfLineSection);
MCOS->SwitchSection(context.getTargetAsmInfo().getDwarfLineSection());
// Create a symbol at the beginning of this section.
MCSymbol *LineStartSym = MCOS->getContext().CreateTempSymbol();
MCSymbol *LineStartSym = context.CreateTempSymbol();
// Set the value of the symbol, as we are at the start of the section.
MCOS->EmitLabel(LineStartSym);
// Create a symbol for the end of the section (to be set when we get there).
MCSymbol *LineEndSym = MCOS->getContext().CreateTempSymbol();
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).
@ -221,7 +223,7 @@ void MCDwarfFileTable::Emit(MCStreamer *MCOS,
MCOS->EmitIntValue(2, 2);
// Create a symbol for the end of the prologue (to be set when we get there).
MCSymbol *ProEndSym = MCOS->getContext().CreateTempSymbol(); // Lprologue_end
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
@ -256,7 +258,7 @@ void MCDwarfFileTable::Emit(MCStreamer *MCOS,
// First the directory table.
const std::vector<StringRef> &MCDwarfDirs =
MCOS->getContext().getMCDwarfDirs();
context.getMCDwarfDirs();
for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
@ -290,7 +292,7 @@ void MCDwarfFileTable::Emit(MCStreamer *MCOS,
++it) {
const MCSection *Sec = *it;
const MCLineSection *Line = MCLineSections.lookup(Sec);
EmitDwarfLineTable(MCOS, Sec, Line, DwarfLineSection);
EmitDwarfLineTable(MCOS, Sec, Line);
// Now delete the MCLineSections that were created in MCLineEntry::Make()
// and used to emit the line table.
@ -425,3 +427,187 @@ void MCDwarfFile::dump() const {
print(dbgs());
}
static int getDataAlignmentFactor(MCStreamer &streamer) {
MCContext &context = streamer.getContext();
const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
int size = asmInfo.getPointerSize();
if (asmInfo.getStackGrowthDirection() == TargetFrameInfo::StackGrowsUp)
return size;
else
return -size;
}
/// EmitFrameMoves - Emit frame instructions to describe the layout of the
/// frame.
static void EmitFrameMoves(MCStreamer &streamer,
const std::vector<MachineMove> &Moves,
MCSymbol *BaseLabel, bool isEH) {
MCContext &context = streamer.getContext();
const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
int dataAlignmentFactor = getDataAlignmentFactor(streamer);
for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
const MachineMove &Move = Moves[i];
MCSymbol *Label = Move.getLabel();
// Throw out move if the label is invalid.
if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
const MachineLocation &Dst = Move.getDestination();
const MachineLocation &Src = Move.getSource();
// Advance row if new location.
if (BaseLabel && Label) {
MCSymbol *ThisSym = Label;
if (ThisSym != BaseLabel) {
streamer.EmitIntValue(dwarf::DW_CFA_advance_loc4, 1);
const MCExpr *Length = MakeStartMinusEndExpr(streamer, *BaseLabel,
*ThisSym, 4);
streamer.EmitValue(Length, 4);
BaseLabel = ThisSym;
}
}
// If advancing cfa.
if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
assert(!Src.isReg() && "Machine move not supported yet.");
if (Src.getReg() == MachineLocation::VirtualFP) {
streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_offset, 1);
} else {
streamer.EmitIntValue(dwarf::DW_CFA_def_cfa, 1);
streamer.EmitULEB128IntValue(asmInfo.getDwarfRegNum(Src.getReg(), isEH),
1);
}
streamer.EmitULEB128IntValue(-Src.getOffset(), 1);
continue;
}
if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
assert(Dst.isReg() && "Machine move not supported yet.");
streamer.EmitIntValue(dwarf::DW_CFA_def_cfa_register, 1);
streamer.EmitULEB128IntValue(asmInfo.getDwarfRegNum(Dst.getReg(), isEH));
continue;
}
unsigned Reg = asmInfo.getDwarfRegNum(Src.getReg(), isEH);
int Offset = Dst.getOffset() / 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, 1);
} else {
streamer.EmitIntValue(dwarf::DW_CFA_offset_extended, 1);
streamer.EmitULEB128IntValue(Reg, 1);
streamer.EmitULEB128IntValue(Offset, 1);
}
}
}
static const MCSymbol &EmitCIE(MCStreamer &streamer) {
MCContext &context = streamer.getContext();
const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
const MCSection &section = *asmInfo.getEHFrameSection();
streamer.SwitchSection(&section);
MCSymbol *sectionStart = streamer.getContext().CreateTempSymbol();
MCSymbol *sectionEnd = streamer.getContext().CreateTempSymbol();
// Length
const MCExpr *Length = MakeStartMinusEndExpr(streamer, *sectionStart,
*sectionEnd, 4);
streamer.EmitLabel(sectionStart);
streamer.EmitValue(Length, 4);
// CIE ID
streamer.EmitIntValue(0, 4);
// Version
streamer.EmitIntValue(dwarf::DW_CIE_VERSION, 1);
// Augmentation String
SmallString<8> Augmentation;
Augmentation += "zR";
streamer.EmitBytes(Augmentation.str(), 0);
streamer.EmitIntValue(0, 1);
// Code Alignment Factor
streamer.EmitULEB128IntValue(1);
// Data Alignment Factor
streamer.EmitSLEB128IntValue(getDataAlignmentFactor(streamer));
// Return Address Register
streamer.EmitULEB128IntValue(asmInfo.getDwarfRARegNum(true));
// Augmentation Data Length (optional)
MCSymbol *augmentationStart = streamer.getContext().CreateTempSymbol();
MCSymbol *augmentationEnd = streamer.getContext().CreateTempSymbol();
const MCExpr *augmentationLength = MakeStartMinusEndExpr(streamer,
*augmentationStart,
*augmentationEnd, 0);
streamer.EmitULEB128Value(augmentationLength);
// Augmentation Data (optional)
streamer.EmitLabel(augmentationStart);
streamer.EmitIntValue(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4, 1);
streamer.EmitLabel(augmentationEnd);
// Initial Instructions
const std::vector<MachineMove> Moves = asmInfo.getInitialFrameState();
EmitFrameMoves(streamer, Moves, NULL, true);
// Padding
streamer.EmitValueToAlignment(asmInfo.getPointerSize());
streamer.EmitLabel(sectionEnd);
return *sectionStart;
}
static void EmitFDE(MCStreamer &streamer,
const MCSymbol &cieStart,
const MCDwarfFrameInfo &frame) {
MCContext &context = streamer.getContext();
const TargetAsmInfo &asmInfo = context.getTargetAsmInfo();
MCSymbol *fdeStart = streamer.getContext().CreateTempSymbol();
MCSymbol *fdeEnd = streamer.getContext().CreateTempSymbol();
// Length
const MCExpr *Length = MakeStartMinusEndExpr(streamer, *fdeStart, *fdeEnd, 0);
streamer.EmitValue(Length, 4);
streamer.EmitLabel(fdeStart);
// CIE Pointer
const MCExpr *offset = MakeStartMinusEndExpr(streamer, cieStart, *fdeStart,
0);
streamer.EmitValue(offset, 4);
// PC Begin
streamer.EmitPCRelSymbolValue(frame.Begin, 4);
// PC Range
const MCExpr *Range = MakeStartMinusEndExpr(streamer, *frame.Begin,
*frame.End, 0);
streamer.EmitValue(Range, 4);
// Augmentation Data Length
streamer.EmitULEB128IntValue(0);
// Augmentation Data
// Call Frame Instructions
// Padding
streamer.EmitValueToAlignment(asmInfo.getPointerSize());
streamer.EmitLabel(fdeEnd);
}
void MCDwarfFrameEmitter::Emit(MCStreamer &streamer) {
const MCSymbol &cieStart = EmitCIE(streamer);
for (unsigned i = 0, n = streamer.getNumFrameInfos(); i < n; ++i)
EmitFDE(streamer, cieStart, streamer.getFrameInfo(i));
}