llvm/lib/CodeGen/AsmPrinter/DwarfPrinter.cpp
Chris Lattner c618c8aff4 emit jump table an alias ".set" directives through MCStreamer as
assignments.

.set x, a-b

is the same as:

x = a-b



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94596 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-26 21:53:08 +00:00

342 lines
12 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/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
DwarfPrinter::DwarfPrinter(raw_ostream &OS, AsmPrinter *A, const MCAsmInfo *T,
const char *flavor)
: O(OS), Asm(A), MAI(T), TD(Asm->TM.getTargetData()),
RI(Asm->TM.getRegisterInfo()), M(NULL), MF(NULL), MMI(NULL),
SubprogramCount(0), Flavor(flavor), SetCounter(1) {}
void DwarfPrinter::PrintRelDirective(bool Force32Bit, bool isInSection) const {
if (isInSection && MAI->getDwarfSectionOffsetDirective())
O << MAI->getDwarfSectionOffsetDirective();
else if (Force32Bit || TD->getPointerSize() == sizeof(int32_t))
O << MAI->getData32bitsDirective();
else
O << MAI->getData64bitsDirective();
}
/// EOL - Print a newline character to asm stream. If a comment is present
/// then it will be printed first. Comments should not contain '\n'.
void DwarfPrinter::EOL(const Twine &Comment) const {
if (Asm->VerboseAsm && !Comment.isTriviallyEmpty()) {
Asm->O.PadToColumn(MAI->getCommentColumn());
Asm->O << Asm->MAI->getCommentString() << ' ' << Comment;
}
Asm->O << '\n';
}
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()) {
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) const {
if (Asm->VerboseAsm && Desc)
Asm->OutStreamer.AddComment(Desc);
if (MAI->hasLEB128()) {
O << "\t.uleb128\t" << Value;
Asm->OutStreamer.AddBlankLine();
return;
}
// If we don't have .uleb128, emit as .bytes.
do {
unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
Value >>= 7;
if (Value) Byte |= 0x80;
Asm->OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
} while (Value);
}
/// PrintLabelName - Print label name in form used by Dwarf writer.
///
void DwarfPrinter::PrintLabelName(const char *Tag, unsigned Number) const {
O << MAI->getPrivateGlobalPrefix() << Tag;
if (Number) O << Number;
}
void DwarfPrinter::PrintLabelName(const char *Tag, unsigned Number,
const char *Suffix) const {
O << MAI->getPrivateGlobalPrefix() << Tag;
if (Number) O << Number;
O << Suffix;
}
/// EmitLabel - Emit location label for internal use by Dwarf.
///
void DwarfPrinter::EmitLabel(const char *Tag, unsigned Number) const {
PrintLabelName(Tag, Number);
O << ":\n";
}
/// EmitReference - Emit a reference to a label.
///
void DwarfPrinter::EmitReference(const char *Tag, unsigned Number,
bool IsPCRelative, bool Force32Bit) const {
PrintRelDirective(Force32Bit);
PrintLabelName(Tag, Number);
if (IsPCRelative) O << "-" << MAI->getPCSymbol();
}
void DwarfPrinter::EmitReference(const std::string &Name, bool IsPCRelative,
bool Force32Bit) const {
PrintRelDirective(Force32Bit);
O << Name;
if (IsPCRelative) O << "-" << MAI->getPCSymbol();
}
void DwarfPrinter::EmitReference(const MCSymbol *Sym, bool IsPCRelative,
bool Force32Bit) const {
PrintRelDirective(Force32Bit);
O << *Sym;
if (IsPCRelative) O << "-" << MAI->getPCSymbol();
}
/// 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 char *TagHi, unsigned NumberHi,
const char *TagLo, unsigned NumberLo,
bool IsSmall) {
if (MAI->hasSetDirective()) {
// FIXME: switch to OutStreamer.EmitAssignment.
O << "\t.set\t";
PrintLabelName("set", SetCounter, Flavor);
O << ",";
PrintLabelName(TagHi, NumberHi);
O << "-";
PrintLabelName(TagLo, NumberLo);
O << "\n";
PrintRelDirective(IsSmall);
PrintLabelName("set", SetCounter, Flavor);
++SetCounter;
} else {
PrintRelDirective(IsSmall);
PrintLabelName(TagHi, NumberHi);
O << "-";
PrintLabelName(TagLo, NumberLo);
}
}
void DwarfPrinter::EmitSectionOffset(const char* Label, const char* Section,
unsigned LabelNumber,
unsigned SectionNumber,
bool IsSmall, bool isEH,
bool useSet) {
bool printAbsolute = false;
if (isEH)
printAbsolute = MAI->isAbsoluteEHSectionOffsets();
else
printAbsolute = MAI->isAbsoluteDebugSectionOffsets();
if (MAI->hasSetDirective() && useSet) {
// FIXME: switch to OutStreamer.EmitAssignment.
O << "\t.set\t";
PrintLabelName("set", SetCounter, Flavor);
O << ",";
PrintLabelName(Label, LabelNumber);
if (!printAbsolute) {
O << "-";
PrintLabelName(Section, SectionNumber);
}
O << "\n";
PrintRelDirective(IsSmall);
PrintLabelName("set", SetCounter, Flavor);
++SetCounter;
O << "\n";
} else {
PrintRelDirective(IsSmall, true);
PrintLabelName(Label, LabelNumber);
if (!printAbsolute) {
O << "-";
PrintLabelName(Section, SectionNumber);
}
O << "\n";
}
}
/// EmitFrameMoves - Emit frame instructions to describe the layout of the
/// frame.
void DwarfPrinter::EmitFrameMoves(const char *BaseLabel, unsigned BaseLabelID,
const std::vector<MachineMove> &Moves,
bool isEH) {
int stackGrowth =
Asm->TM.getFrameInfo()->getStackGrowthDirection() ==
TargetFrameInfo::StackGrowsUp ?
TD->getPointerSize() : -TD->getPointerSize();
bool IsLocal = BaseLabel && strcmp(BaseLabel, "label") == 0;
for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
const MachineMove &Move = Moves[i];
unsigned LabelID = Move.getLabelID();
if (LabelID) {
LabelID = MMI->MappedLabel(LabelID);
// Throw out move if the label is invalid.
if (!LabelID) continue;
}
const MachineLocation &Dst = Move.getDestination();
const MachineLocation &Src = Move.getSource();
// Advance row if new location.
if (BaseLabel && LabelID && (BaseLabelID != LabelID || !IsLocal)) {
EmitCFAByte(dwarf::DW_CFA_advance_loc4);
EmitDifference("label", LabelID, BaseLabel, BaseLabelID, true);
Asm->O << '\n';
BaseLabelID = LabelID;
BaseLabel = "label";
IsLocal = true;
}
// 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");
}
}
}
}