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//===--- 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/Target/TargetMachine.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/ADT/SmallString.h"
using namespace llvm;
DwarfPrinter::DwarfPrinter(AsmPrinter *A)
: Asm(A), MAI(A->MAI), TD(Asm->TM.getTargetData()),
RI(Asm->TM.getRegisterInfo()), M(NULL), MF(NULL), MMI(NULL),
SubprogramCount(0) {
}
/// EmitSectionOffset - Emit the 4-byte offset of Label from the start of its
/// section. This can be done with a special directive if the target supports
/// it (e.g. cygwin) or by emitting it as an offset from a label at the start
/// of the section.
///
/// SectionLabel is a temporary label emitted at the start of the section that
/// Label lives in.
void DwarfPrinter::EmitSectionOffset(const MCSymbol *Label,
const MCSymbol *SectionLabel) const {
// On COFF targets, we have to emit the special .secrel32 directive.
if (const char *SecOffDir = MAI->getDwarfSectionOffsetDirective()) {
// FIXME: MCize.
Asm->OutStreamer.EmitRawText(SecOffDir + Twine(Label->getName()));
return;
}
// Get the section that we're referring to, based on SectionLabel.
const MCSection &Section = SectionLabel->getSection();
// If Label has already been emitted, verify that it is in the same section as
// section label for sanity.
assert((!Label->isInSection() || &Label->getSection() == &Section) &&
"Section offset using wrong section base for label"); (void)Section;
// If the section in question will end up with an address of 0 anyway, we can
// just emit an absolute reference to save a relocation.
if (MAI->isAbsoluteDebugSectionOffsets()) {
Asm->OutStreamer.EmitSymbolValue(Label, 4, 0/*AddrSpace*/);
return;
}
Asm->EmitLabelDifference(Label, SectionLabel, 4);
}
/// 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];
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) {
Asm->EmitCFAByte(dwarf::DW_CFA_advance_loc4);
Asm->EmitLabelDifference(ThisSym, BaseLabel, 4);
BaseLabel = ThisSym;
}
}
// If advancing cfa.
if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
if (!Src.isReg()) {
if (Src.getReg() == MachineLocation::VirtualFP) {
Asm->EmitCFAByte(dwarf::DW_CFA_def_cfa_offset);
} else {
Asm->EmitCFAByte(dwarf::DW_CFA_def_cfa);
Asm->EmitULEB128(RI->getDwarfRegNum(Src.getReg(), isEH), "Register");
}
int Offset = -Src.getOffset();
Asm->EmitULEB128(Offset, "Offset");
} else {
llvm_unreachable("Machine move not supported yet.");
}
} else if (Src.isReg() &&
Src.getReg() == MachineLocation::VirtualFP) {
if (Dst.isReg()) {
Asm->EmitCFAByte(dwarf::DW_CFA_def_cfa_register);
Asm->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) {
Asm->EmitCFAByte(dwarf::DW_CFA_offset_extended_sf);
Asm->EmitULEB128(Reg, "Reg");
Asm->EmitSLEB128(Offset, "Offset");
} else if (Reg < 64) {
Asm->EmitCFAByte(dwarf::DW_CFA_offset + Reg);
Asm->EmitULEB128(Offset, "Offset");
} else {
Asm->EmitCFAByte(dwarf::DW_CFA_offset_extended);
Asm->EmitULEB128(Reg, "Reg");
Asm->EmitULEB128(Offset, "Offset");
}
}
}
}
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