forked from OSchip/llvm-project
301 lines
10 KiB
C++
301 lines
10 KiB
C++
//===-- AsmPrinterDwarf.cpp - AsmPrinter Dwarf Support --------------------===//
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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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//
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// This file implements the Dwarf emissions parts of AsmPrinter.
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//
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//===----------------------------------------------------------------------===//
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#include "ByteStreamer.h"
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#include "DwarfDebug.h"
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#include "DwarfExpression.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/CodeGen/AsmPrinter.h"
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#include "llvm/CodeGen/DIE.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/MC/MCAsmInfo.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/MCStreamer.h"
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#include "llvm/MC/MCSymbol.h"
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#include "llvm/MC/MachineLocation.h"
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#include "llvm/Support/Dwarf.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Target/TargetLoweringObjectFile.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetSubtargetInfo.h"
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using namespace llvm;
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#define DEBUG_TYPE "asm-printer"
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//===----------------------------------------------------------------------===//
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// Dwarf Emission Helper Routines
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//===----------------------------------------------------------------------===//
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/// EmitSLEB128 - emit the specified signed leb128 value.
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void AsmPrinter::EmitSLEB128(int64_t Value, const char *Desc) const {
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if (isVerbose() && Desc)
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OutStreamer->AddComment(Desc);
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OutStreamer->EmitSLEB128IntValue(Value);
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}
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/// EmitULEB128 - emit the specified signed leb128 value.
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void AsmPrinter::EmitULEB128(uint64_t Value, const char *Desc,
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unsigned PadTo) const {
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if (isVerbose() && Desc)
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OutStreamer->AddComment(Desc);
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OutStreamer->EmitULEB128IntValue(Value, PadTo);
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}
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/// EmitCFAByte - Emit a .byte 42 directive for a DW_CFA_xxx value.
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void AsmPrinter::EmitCFAByte(unsigned Val) const {
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if (isVerbose()) {
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if (Val >= dwarf::DW_CFA_offset && Val < dwarf::DW_CFA_offset + 64)
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OutStreamer->AddComment("DW_CFA_offset + Reg (" +
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Twine(Val - dwarf::DW_CFA_offset) + ")");
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else
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OutStreamer->AddComment(dwarf::CallFrameString(Val));
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}
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OutStreamer->EmitIntValue(Val, 1);
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}
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static const char *DecodeDWARFEncoding(unsigned Encoding) {
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switch (Encoding) {
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case dwarf::DW_EH_PE_absptr:
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return "absptr";
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case dwarf::DW_EH_PE_omit:
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return "omit";
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case dwarf::DW_EH_PE_pcrel:
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return "pcrel";
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case dwarf::DW_EH_PE_udata4:
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return "udata4";
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case dwarf::DW_EH_PE_udata8:
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return "udata8";
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case dwarf::DW_EH_PE_sdata4:
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return "sdata4";
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case dwarf::DW_EH_PE_sdata8:
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return "sdata8";
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case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
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return "pcrel udata4";
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case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
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return "pcrel sdata4";
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case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
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return "pcrel udata8";
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case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
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return "pcrel sdata8";
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case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4
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:
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return "indirect pcrel udata4";
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case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
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:
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return "indirect pcrel sdata4";
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case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8
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:
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return "indirect pcrel udata8";
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case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8
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:
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return "indirect pcrel sdata8";
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}
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return "<unknown encoding>";
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}
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/// EmitEncodingByte - Emit a .byte 42 directive that corresponds to an
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/// encoding. If verbose assembly output is enabled, we output comments
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/// describing the encoding. Desc is an optional string saying what the
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/// encoding is specifying (e.g. "LSDA").
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void AsmPrinter::EmitEncodingByte(unsigned Val, const char *Desc) const {
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if (isVerbose()) {
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if (Desc)
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OutStreamer->AddComment(Twine(Desc) + " Encoding = " +
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Twine(DecodeDWARFEncoding(Val)));
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else
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OutStreamer->AddComment(Twine("Encoding = ") + DecodeDWARFEncoding(Val));
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}
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OutStreamer->EmitIntValue(Val, 1);
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}
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/// GetSizeOfEncodedValue - Return the size of the encoding in bytes.
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unsigned AsmPrinter::GetSizeOfEncodedValue(unsigned Encoding) const {
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if (Encoding == dwarf::DW_EH_PE_omit)
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return 0;
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switch (Encoding & 0x07) {
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default:
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llvm_unreachable("Invalid encoded value.");
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case dwarf::DW_EH_PE_absptr:
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return TM.getDataLayout()->getPointerSize();
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case dwarf::DW_EH_PE_udata2:
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return 2;
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case dwarf::DW_EH_PE_udata4:
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return 4;
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case dwarf::DW_EH_PE_udata8:
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return 8;
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}
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}
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void AsmPrinter::EmitTTypeReference(const GlobalValue *GV,
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unsigned Encoding) const {
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if (GV) {
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const TargetLoweringObjectFile &TLOF = getObjFileLowering();
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const MCExpr *Exp =
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TLOF.getTTypeGlobalReference(GV, Encoding, *Mang, TM, MMI,
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*OutStreamer);
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OutStreamer->EmitValue(Exp, GetSizeOfEncodedValue(Encoding));
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} else
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OutStreamer->EmitIntValue(0, GetSizeOfEncodedValue(Encoding));
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}
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void AsmPrinter::emitDwarfSymbolReference(const MCSymbol *Label,
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bool ForceOffset) const {
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if (!ForceOffset) {
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// On COFF targets, we have to emit the special .secrel32 directive.
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if (MAI->needsDwarfSectionOffsetDirective()) {
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OutStreamer->EmitCOFFSecRel32(Label);
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return;
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}
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// If the format uses relocations with dwarf, refer to the symbol directly.
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if (MAI->doesDwarfUseRelocationsAcrossSections()) {
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OutStreamer->EmitSymbolValue(Label, 4);
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return;
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}
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}
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// Otherwise, emit it as a label difference from the start of the section.
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EmitLabelDifference(Label, Label->getSection().getBeginSymbol(), 4);
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}
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void AsmPrinter::emitDwarfStringOffset(DwarfStringPoolEntryRef S) const {
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if (MAI->doesDwarfUseRelocationsAcrossSections()) {
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emitDwarfSymbolReference(S.getSymbol());
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return;
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}
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// Just emit the offset directly; no need for symbol math.
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EmitInt32(S.getOffset());
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}
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/// EmitDwarfRegOp - Emit dwarf register operation.
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void AsmPrinter::EmitDwarfRegOp(ByteStreamer &Streamer,
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const MachineLocation &MLoc) const {
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DebugLocDwarfExpression Expr(*MF->getSubtarget().getRegisterInfo(),
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getDwarfDebug()->getDwarfVersion(), Streamer);
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const MCRegisterInfo *MRI = MMI->getContext().getRegisterInfo();
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int Reg = MRI->getDwarfRegNum(MLoc.getReg(), false);
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if (Reg < 0) {
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// We assume that pointers are always in an addressable register.
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if (MLoc.isIndirect())
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// FIXME: We have no reasonable way of handling errors in here. The
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// caller might be in the middle of a dwarf expression. We should
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// probably assert that Reg >= 0 once debug info generation is more
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// mature.
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return Expr.EmitOp(dwarf::DW_OP_nop,
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"nop (could not find a dwarf register number)");
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// Attempt to find a valid super- or sub-register.
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if (!Expr.AddMachineRegPiece(MLoc.getReg()))
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Expr.EmitOp(dwarf::DW_OP_nop,
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"nop (could not find a dwarf register number)");
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return;
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}
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if (MLoc.isIndirect())
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Expr.AddRegIndirect(Reg, MLoc.getOffset());
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else
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Expr.AddReg(Reg);
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}
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//===----------------------------------------------------------------------===//
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// Dwarf Lowering Routines
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//===----------------------------------------------------------------------===//
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void AsmPrinter::emitCFIInstruction(const MCCFIInstruction &Inst) const {
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switch (Inst.getOperation()) {
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default:
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llvm_unreachable("Unexpected instruction");
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case MCCFIInstruction::OpDefCfaOffset:
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OutStreamer->EmitCFIDefCfaOffset(Inst.getOffset());
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break;
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case MCCFIInstruction::OpDefCfa:
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OutStreamer->EmitCFIDefCfa(Inst.getRegister(), Inst.getOffset());
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break;
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case MCCFIInstruction::OpDefCfaRegister:
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OutStreamer->EmitCFIDefCfaRegister(Inst.getRegister());
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break;
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case MCCFIInstruction::OpOffset:
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OutStreamer->EmitCFIOffset(Inst.getRegister(), Inst.getOffset());
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break;
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case MCCFIInstruction::OpRegister:
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OutStreamer->EmitCFIRegister(Inst.getRegister(), Inst.getRegister2());
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break;
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case MCCFIInstruction::OpWindowSave:
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OutStreamer->EmitCFIWindowSave();
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break;
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case MCCFIInstruction::OpSameValue:
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OutStreamer->EmitCFISameValue(Inst.getRegister());
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break;
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}
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}
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void AsmPrinter::emitDwarfDIE(const DIE &Die) const {
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// Emit the code (index) for the abbreviation.
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if (isVerbose())
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OutStreamer->AddComment("Abbrev [" + Twine(Die.getAbbrevNumber()) + "] 0x" +
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Twine::utohexstr(Die.getOffset()) + ":0x" +
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Twine::utohexstr(Die.getSize()) + " " +
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dwarf::TagString(Die.getTag()));
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EmitULEB128(Die.getAbbrevNumber());
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// Emit the DIE attribute values.
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for (const auto &V : Die.values()) {
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dwarf::Attribute Attr = V.getAttribute();
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assert(V.getForm() && "Too many attributes for DIE (check abbreviation)");
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if (isVerbose()) {
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OutStreamer->AddComment(dwarf::AttributeString(Attr));
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if (Attr == dwarf::DW_AT_accessibility)
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OutStreamer->AddComment(
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dwarf::AccessibilityString(V.getDIEInteger().getValue()));
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}
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// Emit an attribute using the defined form.
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V.EmitValue(this);
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}
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// Emit the DIE children if any.
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if (Die.hasChildren()) {
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for (auto &Child : Die.children())
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emitDwarfDIE(Child);
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OutStreamer->AddComment("End Of Children Mark");
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EmitInt8(0);
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}
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}
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void
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AsmPrinter::emitDwarfAbbrevs(const std::vector<DIEAbbrev *>& Abbrevs) const {
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// For each abbrevation.
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for (const DIEAbbrev *Abbrev : Abbrevs) {
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// Emit the abbrevations code (base 1 index.)
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EmitULEB128(Abbrev->getNumber(), "Abbreviation Code");
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// Emit the abbreviations data.
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Abbrev->Emit(this);
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}
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// Mark end of abbreviations.
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EmitULEB128(0, "EOM(3)");
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}
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