llvm/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp
Chris Lattner 5e6cbe0eff simplify EmitFrameMoves to take BaseLabel in as a symbol
instead of as a stem+idx pair, simplify the "is a new 
location" check to use symbol comparison.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98432 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-13 08:05:25 +00:00

311 lines
11 KiB
C++

//===--- lib/CodeGen/DwarfPrinter.cpp - Dwarf Printer ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Emit general DWARF directives.
//
//===----------------------------------------------------------------------===//
#include "DwarfPrinter.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/ADT/SmallString.h"
using namespace llvm;
DwarfPrinter::DwarfPrinter(raw_ostream &OS, AsmPrinter *A, const MCAsmInfo *T)
: O(OS), Asm(A), MAI(T), TD(Asm->TM.getTargetData()),
RI(Asm->TM.getRegisterInfo()), M(NULL), MF(NULL), MMI(NULL),
SubprogramCount(0) {}
/// getDWLabel - Return the MCSymbol corresponding to the assembler temporary
/// label with the specified stem and unique ID.
MCSymbol *DwarfPrinter::getDWLabel(const char *Name, unsigned ID) const {
// FIXME: REMOVE this. However, there is stuff in EH that passes counters in
// here that can be zero.
//assert(ID && "Should use getTempLabel if no ID");
if (ID == 0) return getTempLabel(Name);
return Asm->OutContext.GetOrCreateTemporarySymbol
(Twine(MAI->getPrivateGlobalPrefix()) + Twine(Name) + Twine(ID));
}
/// getTempLabel - Return the MCSymbol corresponding to the assembler temporary
/// label with the specified name.
MCSymbol *DwarfPrinter::getTempLabel(const char *Name) const {
return Asm->OutContext.GetOrCreateTemporarySymbol
(Twine(MAI->getPrivateGlobalPrefix()) + Name);
}
/// SizeOfEncodedValue - Return the size of the encoding in bytes.
unsigned DwarfPrinter::SizeOfEncodedValue(unsigned Encoding) const {
if (Encoding == dwarf::DW_EH_PE_omit)
return 0;
switch (Encoding & 0x07) {
case dwarf::DW_EH_PE_absptr:
return TD->getPointerSize();
case dwarf::DW_EH_PE_udata2:
return 2;
case dwarf::DW_EH_PE_udata4:
return 4;
case dwarf::DW_EH_PE_udata8:
return 8;
}
assert(0 && "Invalid encoded value.");
return 0;
}
static const char *DecodeDWARFEncoding(unsigned Encoding) {
switch (Encoding) {
case dwarf::DW_EH_PE_absptr: return "absptr";
case dwarf::DW_EH_PE_omit: return "omit";
case dwarf::DW_EH_PE_pcrel: return "pcrel";
case dwarf::DW_EH_PE_udata4: return "udata4";
case dwarf::DW_EH_PE_udata8: return "udata8";
case dwarf::DW_EH_PE_sdata4: return "sdata4";
case dwarf::DW_EH_PE_sdata8: return "sdata8";
case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4: return "pcrel udata4";
case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4: return "pcrel sdata4";
case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8: return "pcrel udata8";
case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8: return "pcrel sdata8";
case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata4:
return "indirect pcrel udata4";
case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata4:
return "indirect pcrel sdata4";
case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata8:
return "indirect pcrel udata8";
case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata8:
return "indirect pcrel sdata8";
}
return "<unknown encoding>";
}
/// EmitEncodingByte - Emit a .byte 42 directive that corresponds to an
/// encoding. If verbose assembly output is enabled, we output comments
/// describing the encoding. Desc is an optional string saying what the
/// encoding is specifying (e.g. "LSDA").
void DwarfPrinter::EmitEncodingByte(unsigned Val, const char *Desc) {
if (Asm->VerboseAsm) {
if (Desc != 0)
Asm->OutStreamer.AddComment(Twine(Desc)+" Encoding = " +
Twine(DecodeDWARFEncoding(Val)));
else
Asm->OutStreamer.AddComment(Twine("Encoding = ") +
DecodeDWARFEncoding(Val));
}
Asm->OutStreamer.EmitIntValue(Val, 1, 0/*addrspace*/);
}
/// EmitCFAByte - Emit a .byte 42 directive for a DW_CFA_xxx value.
void DwarfPrinter::EmitCFAByte(unsigned Val) {
if (Asm->VerboseAsm) {
if (Val >= dwarf::DW_CFA_offset && Val < dwarf::DW_CFA_offset+64)
Asm->OutStreamer.AddComment("DW_CFA_offset + Reg (" +
Twine(Val-dwarf::DW_CFA_offset) + ")");
else
Asm->OutStreamer.AddComment(dwarf::CallFrameString(Val));
}
Asm->OutStreamer.EmitIntValue(Val, 1, 0/*addrspace*/);
}
/// EmitSLEB128 - emit the specified signed leb128 value.
void DwarfPrinter::EmitSLEB128(int Value, const char *Desc) const {
if (Asm->VerboseAsm && Desc)
Asm->OutStreamer.AddComment(Desc);
if (MAI->hasLEB128()) {
// FIXME: MCize.
O << "\t.sleb128\t" << Value;
Asm->OutStreamer.AddBlankLine();
return;
}
// If we don't have .sleb128, emit as .bytes.
int Sign = Value >> (8 * sizeof(Value) - 1);
bool IsMore;
do {
unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
Value >>= 7;
IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
if (IsMore) Byte |= 0x80;
Asm->OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
} while (IsMore);
}
/// EmitULEB128 - emit the specified signed leb128 value.
void DwarfPrinter::EmitULEB128(unsigned Value, const char *Desc,
unsigned PadTo) const {
if (Asm->VerboseAsm && Desc)
Asm->OutStreamer.AddComment(Desc);
if (MAI->hasLEB128() && PadTo == 0) {
// FIXME: MCize.
O << "\t.uleb128\t" << Value;
Asm->OutStreamer.AddBlankLine();
return;
}
// If we don't have .uleb128 or we want to emit padding, emit as .bytes.
do {
unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
Value >>= 7;
if (Value || PadTo != 0) Byte |= 0x80;
Asm->OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
} while (Value);
if (PadTo) {
if (PadTo > 1)
Asm->OutStreamer.EmitFill(PadTo - 1, 0x80/*fillval*/, 0/*addrspace*/);
Asm->OutStreamer.EmitFill(1, 0/*fillval*/, 0/*addrspace*/);
}
}
void DwarfPrinter::EmitReference(const MCSymbol *Sym, unsigned Encoding) const {
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
const MCExpr *Exp = TLOF.getExprForDwarfReference(Sym, Asm->Mang,
Asm->MMI, Encoding,
Asm->OutStreamer);
Asm->OutStreamer.EmitValue(Exp, SizeOfEncodedValue(Encoding), /*addrspace*/0);
}
void DwarfPrinter::EmitReference(const GlobalValue *GV, unsigned Encoding)const{
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
const MCExpr *Exp =
TLOF.getExprForDwarfGlobalReference(GV, Asm->Mang, Asm->MMI, Encoding,
Asm->OutStreamer);
Asm->OutStreamer.EmitValue(Exp, SizeOfEncodedValue(Encoding), /*addrspace*/0);
}
/// EmitDifference - Emit the difference between two labels. If this assembler
/// supports .set, we emit a .set of a temporary and then use it in the .word.
void DwarfPrinter::EmitDifference(const MCSymbol *TagHi, const MCSymbol *TagLo,
bool IsSmall) {
unsigned Size = IsSmall ? 4 : TD->getPointerSize();
Asm->EmitLabelDifference(TagHi, TagLo, Size);
}
void DwarfPrinter::EmitSectionOffset(const MCSymbol *Label,
const MCSymbol *Section,
bool IsSmall, bool isEH) {
bool isAbsolute;
if (isEH)
isAbsolute = MAI->isAbsoluteEHSectionOffsets();
else
isAbsolute = MAI->isAbsoluteDebugSectionOffsets();
if (!isAbsolute)
return EmitDifference(Label, Section, IsSmall);
// On COFF targets, we have to emit the weird .secrel32 directive.
if (const char *SecOffDir = MAI->getDwarfSectionOffsetDirective()) {
// FIXME: MCize.
Asm->O << SecOffDir << Label->getName();
Asm->OutStreamer.AddBlankLine();
} else {
unsigned Size = IsSmall ? 4 : TD->getPointerSize();
Asm->OutStreamer.EmitSymbolValue(Label, Size, 0/*AddrSpace*/);
}
}
/// EmitFrameMoves - Emit frame instructions to describe the layout of the
/// frame.
void DwarfPrinter::EmitFrameMoves(MCSymbol *BaseLabel,
const std::vector<MachineMove> &Moves,
bool isEH) {
int stackGrowth = TD->getPointerSize();
if (Asm->TM.getFrameInfo()->getStackGrowthDirection() !=
TargetFrameInfo::StackGrowsUp)
stackGrowth *= -1;
for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
const MachineMove &Move = Moves[i];
unsigned LabelID = Move.getLabelID();
// Throw out move if the label is invalid.
if (LabelID && MMI->isLabelDeleted(LabelID))
continue;
const MachineLocation &Dst = Move.getDestination();
const MachineLocation &Src = Move.getSource();
// Advance row if new location.
if (BaseLabel && LabelID) {
MCSymbol *ThisSym = getDWLabel("label", LabelID);
if (ThisSym != BaseLabel) {
EmitCFAByte(dwarf::DW_CFA_advance_loc4);
EmitDifference(ThisSym, BaseLabel, true);
BaseLabel = ThisSym;
}
}
// If advancing cfa.
if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
if (!Src.isReg()) {
if (Src.getReg() == MachineLocation::VirtualFP) {
EmitCFAByte(dwarf::DW_CFA_def_cfa_offset);
} else {
EmitCFAByte(dwarf::DW_CFA_def_cfa);
EmitULEB128(RI->getDwarfRegNum(Src.getReg(), isEH), "Register");
}
int Offset = -Src.getOffset();
EmitULEB128(Offset, "Offset");
} else {
llvm_unreachable("Machine move not supported yet.");
}
} else if (Src.isReg() &&
Src.getReg() == MachineLocation::VirtualFP) {
if (Dst.isReg()) {
EmitCFAByte(dwarf::DW_CFA_def_cfa_register);
EmitULEB128(RI->getDwarfRegNum(Dst.getReg(), isEH), "Register");
} else {
llvm_unreachable("Machine move not supported yet.");
}
} else {
unsigned Reg = RI->getDwarfRegNum(Src.getReg(), isEH);
int Offset = Dst.getOffset() / stackGrowth;
if (Offset < 0) {
EmitCFAByte(dwarf::DW_CFA_offset_extended_sf);
EmitULEB128(Reg, "Reg");
EmitSLEB128(Offset, "Offset");
} else if (Reg < 64) {
EmitCFAByte(dwarf::DW_CFA_offset + Reg);
EmitULEB128(Offset, "Offset");
} else {
EmitCFAByte(dwarf::DW_CFA_offset_extended);
EmitULEB128(Reg, "Reg");
EmitULEB128(Offset, "Offset");
}
}
}
}