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llvm-6502/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
Anton Korobeynikov b5e16af9ea Some first rudimentary support for ARM EHABI: print exception table in "text mode". 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127099 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-05 18:43:15 +00:00

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//===-- AsmPrinter.cpp - Common AsmPrinter code ---------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the AsmPrinter class.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "asm-printer"
#include "llvm/CodeGen/AsmPrinter.h"
#include "DwarfDebug.h"
#include "DwarfException.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/GCMetadataPrinter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/Mangler.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/Timer.h"
using namespace llvm;
static const char *DWARFGroupName = "DWARF Emission";
static const char *DbgTimerName = "DWARF Debug Writer";
static const char *EHTimerName = "DWARF Exception Writer";
STATISTIC(EmittedInsts, "Number of machine instrs printed");
char AsmPrinter::ID = 0;
typedef DenseMap<GCStrategy*,GCMetadataPrinter*> gcp_map_type;
static gcp_map_type &getGCMap(void *&P) {
if (P == 0)
P = new gcp_map_type();
return *(gcp_map_type*)P;
}
/// getGVAlignmentLog2 - Return the alignment to use for the specified global
/// value in log2 form. This rounds up to the preferred alignment if possible
/// and legal.
static unsigned getGVAlignmentLog2(const GlobalValue *GV, const TargetData &TD,
unsigned InBits = 0) {
unsigned NumBits = 0;
if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
NumBits = TD.getPreferredAlignmentLog(GVar);
// If InBits is specified, round it to it.
if (InBits > NumBits)
NumBits = InBits;
// If the GV has a specified alignment, take it into account.
if (GV->getAlignment() == 0)
return NumBits;
unsigned GVAlign = Log2_32(GV->getAlignment());
// If the GVAlign is larger than NumBits, or if we are required to obey
// NumBits because the GV has an assigned section, obey it.
if (GVAlign > NumBits || GV->hasSection())
NumBits = GVAlign;
return NumBits;
}
AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer)
: MachineFunctionPass(ID),
TM(tm), MAI(tm.getMCAsmInfo()),
OutContext(Streamer.getContext()),
OutStreamer(Streamer),
LastMI(0), LastFn(0), Counter(~0U), SetCounter(0) {
DD = 0; DE = 0; MMI = 0; LI = 0;
GCMetadataPrinters = 0;
VerboseAsm = Streamer.isVerboseAsm();
}
AsmPrinter::~AsmPrinter() {
assert(DD == 0 && DE == 0 && "Debug/EH info didn't get finalized");
if (GCMetadataPrinters != 0) {
gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
for (gcp_map_type::iterator I = GCMap.begin(), E = GCMap.end(); I != E; ++I)
delete I->second;
delete &GCMap;
GCMetadataPrinters = 0;
}
delete &OutStreamer;
}
/// getFunctionNumber - Return a unique ID for the current function.
///
unsigned AsmPrinter::getFunctionNumber() const {
return MF->getFunctionNumber();
}
const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
return TM.getTargetLowering()->getObjFileLowering();
}
/// getTargetData - Return information about data layout.
const TargetData &AsmPrinter::getTargetData() const {
return *TM.getTargetData();
}
/// getCurrentSection() - Return the current section we are emitting to.
const MCSection *AsmPrinter::getCurrentSection() const {
return OutStreamer.getCurrentSection();
}
void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
AU.addRequired<MachineModuleInfo>();
AU.addRequired<GCModuleInfo>();
if (isVerbose())
AU.addRequired<MachineLoopInfo>();
}
bool AsmPrinter::doInitialization(Module &M) {
MMI = getAnalysisIfAvailable<MachineModuleInfo>();
MMI->AnalyzeModule(M);
// Initialize TargetLoweringObjectFile.
const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
.Initialize(OutContext, TM);
Mang = new Mangler(OutContext, *TM.getTargetData());
// Allow the target to emit any magic that it wants at the start of the file.
EmitStartOfAsmFile(M);
// Very minimal debug info. It is ignored if we emit actual debug info. If we
// don't, this at least helps the user find where a global came from.
if (MAI->hasSingleParameterDotFile()) {
// .file "foo.c"
OutStreamer.EmitFileDirective(M.getModuleIdentifier());
}
GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
assert(MI && "AsmPrinter didn't require GCModuleInfo?");
for (GCModuleInfo::iterator I = MI->begin(), E = MI->end(); I != E; ++I)
if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
MP->beginAssembly(*this);
// Emit module-level inline asm if it exists.
if (!M.getModuleInlineAsm().empty()) {
OutStreamer.AddComment("Start of file scope inline assembly");
OutStreamer.AddBlankLine();
EmitInlineAsm(M.getModuleInlineAsm()+"\n");
OutStreamer.AddComment("End of file scope inline assembly");
OutStreamer.AddBlankLine();
}
if (MAI->doesSupportDebugInformation())
DD = new DwarfDebug(this, &M);
if (MAI->doesSupportExceptionHandling())
switch (MAI->getExceptionHandlingType()) {
default:
case ExceptionHandling::DwarfTable:
DE = new DwarfTableException(this);
break;
case ExceptionHandling::DwarfCFI:
DE = new DwarfCFIException(this);
break;
case ExceptionHandling::ARM:
DE = new ARMException(this);
break;
}
return false;
}
void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const {
switch ((GlobalValue::LinkageTypes)Linkage) {
case GlobalValue::CommonLinkage:
case GlobalValue::LinkOnceAnyLinkage:
case GlobalValue::LinkOnceODRLinkage:
case GlobalValue::WeakAnyLinkage:
case GlobalValue::WeakODRLinkage:
case GlobalValue::LinkerPrivateWeakLinkage:
case GlobalValue::LinkerPrivateWeakDefAutoLinkage:
if (MAI->getWeakDefDirective() != 0) {
// .globl _foo
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
if ((GlobalValue::LinkageTypes)Linkage !=
GlobalValue::LinkerPrivateWeakDefAutoLinkage)
// .weak_definition _foo
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
else
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
} else if (MAI->getLinkOnceDirective() != 0) {
// .globl _foo
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
//NOTE: linkonce is handled by the section the symbol was assigned to.
} else {
// .weak _foo
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Weak);
}
break;
case GlobalValue::DLLExportLinkage:
case GlobalValue::AppendingLinkage:
// FIXME: appending linkage variables should go into a section of
// their name or something. For now, just emit them as external.
case GlobalValue::ExternalLinkage:
// If external or appending, declare as a global symbol.
// .globl _foo
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
break;
case GlobalValue::PrivateLinkage:
case GlobalValue::InternalLinkage:
case GlobalValue::LinkerPrivateLinkage:
break;
default:
llvm_unreachable("Unknown linkage type!");
}
}
/// EmitGlobalVariable - Emit the specified global variable to the .s file.
void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
if (!GV->hasInitializer()) // External globals require no code.
return;
// Check to see if this is a special global used by LLVM, if so, emit it.
if (EmitSpecialLLVMGlobal(GV))
return;
if (isVerbose()) {
WriteAsOperand(OutStreamer.GetCommentOS(), GV,
/*PrintType=*/false, GV->getParent());
OutStreamer.GetCommentOS() << '\n';
}
MCSymbol *GVSym = Mang->getSymbol(GV);
EmitVisibility(GVSym, GV->getVisibility());
if (MAI->hasDotTypeDotSizeDirective())
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
const TargetData *TD = TM.getTargetData();
uint64_t Size = TD->getTypeAllocSize(GV->getType()->getElementType());
// If the alignment is specified, we *must* obey it. Overaligning a global
// with a specified alignment is a prompt way to break globals emitted to
// sections and expected to be contiguous (e.g. ObjC metadata).
unsigned AlignLog = getGVAlignmentLog2(GV, *TD);
// Handle common and BSS local symbols (.lcomm).
if (GVKind.isCommon() || GVKind.isBSSLocal()) {
if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
if (isVerbose()) {
WriteAsOperand(OutStreamer.GetCommentOS(), GV,
/*PrintType=*/false, GV->getParent());
OutStreamer.GetCommentOS() << '\n';
}
// Handle common symbols.
if (GVKind.isCommon()) {
unsigned Align = 1 << AlignLog;
if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
Align = 0;
// .comm _foo, 42, 4
OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
return;
}
// Handle local BSS symbols.
if (MAI->hasMachoZeroFillDirective()) {
const MCSection *TheSection =
getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
// .zerofill __DATA, __bss, _foo, 400, 5
OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
return;
}
if (MAI->hasLCOMMDirective()) {
// .lcomm _foo, 42
OutStreamer.EmitLocalCommonSymbol(GVSym, Size);
return;
}
unsigned Align = 1 << AlignLog;
if (!getObjFileLowering().getCommDirectiveSupportsAlignment())
Align = 0;
// .local _foo
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Local);
// .comm _foo, 42, 4
OutStreamer.EmitCommonSymbol(GVSym, Size, Align);
return;
}
const MCSection *TheSection =
getObjFileLowering().SectionForGlobal(GV, GVKind, Mang, TM);
// Handle the zerofill directive on darwin, which is a special form of BSS
// emission.
if (GVKind.isBSSExtern() && MAI->hasMachoZeroFillDirective()) {
if (Size == 0) Size = 1; // zerofill of 0 bytes is undefined.
// .globl _foo
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
// .zerofill __DATA, __common, _foo, 400, 5
OutStreamer.EmitZerofill(TheSection, GVSym, Size, 1 << AlignLog);
return;
}
// Handle thread local data for mach-o which requires us to output an
// additional structure of data and mangle the original symbol so that we
// can reference it later.
//
// TODO: This should become an "emit thread local global" method on TLOF.
// All of this macho specific stuff should be sunk down into TLOFMachO and
// stuff like "TLSExtraDataSection" should no longer be part of the parent
// TLOF class. This will also make it more obvious that stuff like
// MCStreamer::EmitTBSSSymbol is macho specific and only called from macho
// specific code.
if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) {
// Emit the .tbss symbol
MCSymbol *MangSym =
OutContext.GetOrCreateSymbol(GVSym->getName() + Twine("$tlv$init"));
if (GVKind.isThreadBSS())
OutStreamer.EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog);
else if (GVKind.isThreadData()) {
OutStreamer.SwitchSection(TheSection);
EmitAlignment(AlignLog, GV);
OutStreamer.EmitLabel(MangSym);
EmitGlobalConstant(GV->getInitializer());
}
OutStreamer.AddBlankLine();
// Emit the variable struct for the runtime.
const MCSection *TLVSect
= getObjFileLowering().getTLSExtraDataSection();
OutStreamer.SwitchSection(TLVSect);
// Emit the linkage here.
EmitLinkage(GV->getLinkage(), GVSym);
OutStreamer.EmitLabel(GVSym);
// Three pointers in size:
// - __tlv_bootstrap - used to make sure support exists
// - spare pointer, used when mapped by the runtime
// - pointer to mangled symbol above with initializer
unsigned PtrSize = TD->getPointerSizeInBits()/8;
OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
PtrSize, 0);
OutStreamer.EmitIntValue(0, PtrSize, 0);
OutStreamer.EmitSymbolValue(MangSym, PtrSize, 0);
OutStreamer.AddBlankLine();
return;
}
OutStreamer.SwitchSection(TheSection);
EmitLinkage(GV->getLinkage(), GVSym);
EmitAlignment(AlignLog, GV);
OutStreamer.EmitLabel(GVSym);
EmitGlobalConstant(GV->getInitializer());
if (MAI->hasDotTypeDotSizeDirective())
// .size foo, 42
OutStreamer.EmitELFSize(GVSym, MCConstantExpr::Create(Size, OutContext));
OutStreamer.AddBlankLine();
}
/// EmitFunctionHeader - This method emits the header for the current
/// function.
void AsmPrinter::EmitFunctionHeader() {
// Print out constants referenced by the function
EmitConstantPool();
// Print the 'header' of function.
const Function *F = MF->getFunction();
OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));
EmitVisibility(CurrentFnSym, F->getVisibility());
EmitLinkage(F->getLinkage(), CurrentFnSym);
EmitAlignment(MF->getAlignment(), F);
if (MAI->hasDotTypeDotSizeDirective())
OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
if (isVerbose()) {
WriteAsOperand(OutStreamer.GetCommentOS(), F,
/*PrintType=*/false, F->getParent());
OutStreamer.GetCommentOS() << '\n';
}
// Emit the CurrentFnSym. This is a virtual function to allow targets to
// do their wild and crazy things as required.
EmitFunctionEntryLabel();
// If the function had address-taken blocks that got deleted, then we have
// references to the dangling symbols. Emit them at the start of the function
// so that we don't get references to undefined symbols.
std::vector<MCSymbol*> DeadBlockSyms;
MMI->takeDeletedSymbolsForFunction(F, DeadBlockSyms);
for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {
OutStreamer.AddComment("Address taken block that was later removed");
OutStreamer.EmitLabel(DeadBlockSyms[i]);
}
// Add some workaround for linkonce linkage on Cygwin\MinGW.
if (MAI->getLinkOnceDirective() != 0 &&
(F->hasLinkOnceLinkage() || F->hasWeakLinkage())) {
// FIXME: What is this?
MCSymbol *FakeStub =
OutContext.GetOrCreateSymbol(Twine("Lllvm$workaround$fake$stub$")+
CurrentFnSym->getName());
OutStreamer.EmitLabel(FakeStub);
}
// Emit pre-function debug and/or EH information.
if (DE) {
NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
DE->BeginFunction(MF);
}
if (DD) {
NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
DD->beginFunction(MF);
}
}
/// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
/// function. This can be overridden by targets as required to do custom stuff.
void AsmPrinter::EmitFunctionEntryLabel() {
// The function label could have already been emitted if two symbols end up
// conflicting due to asm renaming. Detect this and emit an error.
if (CurrentFnSym->isUndefined())
return OutStreamer.EmitLabel(CurrentFnSym);
report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
"' label emitted multiple times to assembly file");
}
static void EmitDebugLoc(DebugLoc DL, const MachineFunction *MF,
raw_ostream &CommentOS) {
const LLVMContext &Ctx = MF->getFunction()->getContext();
if (!DL.isUnknown()) { // Print source line info.
DIScope Scope(DL.getScope(Ctx));
// Omit the directory, because it's likely to be long and uninteresting.
if (Scope.Verify())
CommentOS << Scope.getFilename();
else
CommentOS << "<unknown>";
CommentOS << ':' << DL.getLine();
if (DL.getCol() != 0)
CommentOS << ':' << DL.getCol();
DebugLoc InlinedAtDL = DebugLoc::getFromDILocation(DL.getInlinedAt(Ctx));
if (!InlinedAtDL.isUnknown()) {
CommentOS << "[ ";
EmitDebugLoc(InlinedAtDL, MF, CommentOS);
CommentOS << " ]";
}
}
}
/// EmitComments - Pretty-print comments for instructions.
static void EmitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
const MachineFunction *MF = MI.getParent()->getParent();
const TargetMachine &TM = MF->getTarget();
DebugLoc DL = MI.getDebugLoc();
if (!DL.isUnknown()) { // Print source line info.
EmitDebugLoc(DL, MF, CommentOS);
CommentOS << '\n';
}
// Check for spills and reloads
int FI;
const MachineFrameInfo *FrameInfo = MF->getFrameInfo();
// We assume a single instruction only has a spill or reload, not
// both.
const MachineMemOperand *MMO;
if (TM.getInstrInfo()->isLoadFromStackSlotPostFE(&MI, FI)) {
if (FrameInfo->isSpillSlotObjectIndex(FI)) {
MMO = *MI.memoperands_begin();
CommentOS << MMO->getSize() << "-byte Reload\n";
}
} else if (TM.getInstrInfo()->hasLoadFromStackSlot(&MI, MMO, FI)) {
if (FrameInfo->isSpillSlotObjectIndex(FI))
CommentOS << MMO->getSize() << "-byte Folded Reload\n";
} else if (TM.getInstrInfo()->isStoreToStackSlotPostFE(&MI, FI)) {
if (FrameInfo->isSpillSlotObjectIndex(FI)) {
MMO = *MI.memoperands_begin();
CommentOS << MMO->getSize() << "-byte Spill\n";
}
} else if (TM.getInstrInfo()->hasStoreToStackSlot(&MI, MMO, FI)) {
if (FrameInfo->isSpillSlotObjectIndex(FI))
CommentOS << MMO->getSize() << "-byte Folded Spill\n";
}
// Check for spill-induced copies
if (MI.getAsmPrinterFlag(MachineInstr::ReloadReuse))
CommentOS << " Reload Reuse\n";
}
/// EmitImplicitDef - This method emits the specified machine instruction
/// that is an implicit def.
static void EmitImplicitDef(const MachineInstr *MI, AsmPrinter &AP) {
unsigned RegNo = MI->getOperand(0).getReg();
AP.OutStreamer.AddComment(Twine("implicit-def: ") +
AP.TM.getRegisterInfo()->getName(RegNo));
AP.OutStreamer.AddBlankLine();
}
static void EmitKill(const MachineInstr *MI, AsmPrinter &AP) {
std::string Str = "kill:";
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &Op = MI->getOperand(i);
assert(Op.isReg() && "KILL instruction must have only register operands");
Str += ' ';
Str += AP.TM.getRegisterInfo()->getName(Op.getReg());
Str += (Op.isDef() ? "<def>" : "<kill>");
}
AP.OutStreamer.AddComment(Str);
AP.OutStreamer.AddBlankLine();
}
/// EmitDebugValueComment - This method handles the target-independent form
/// of DBG_VALUE, returning true if it was able to do so. A false return
/// means the target will need to handle MI in EmitInstruction.
static bool EmitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
// This code handles only the 3-operand target-independent form.
if (MI->getNumOperands() != 3)
return false;
SmallString<128> Str;
raw_svector_ostream OS(Str);
OS << '\t' << AP.MAI->getCommentString() << "DEBUG_VALUE: ";
// cast away const; DIetc do not take const operands for some reason.
DIVariable V(const_cast<MDNode*>(MI->getOperand(2).getMetadata()));
if (V.getContext().isSubprogram())
OS << DISubprogram(V.getContext()).getDisplayName() << ":";
OS << V.getName() << " <- ";
// Register or immediate value. Register 0 means undef.
if (MI->getOperand(0).isFPImm()) {
APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF());
if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) {
OS << (double)APF.convertToFloat();
} else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) {
OS << APF.convertToDouble();
} else {
// There is no good way to print long double. Convert a copy to
// double. Ah well, it's only a comment.
bool ignored;
APF.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
&ignored);
OS << "(long double) " << APF.convertToDouble();
}
} else if (MI->getOperand(0).isImm()) {
OS << MI->getOperand(0).getImm();
} else {
assert(MI->getOperand(0).isReg() && "Unknown operand type");
if (MI->getOperand(0).getReg() == 0) {
// Suppress offset, it is not meaningful here.
OS << "undef";
// NOTE: Want this comment at start of line, don't emit with AddComment.
AP.OutStreamer.EmitRawText(OS.str());
return true;
}
OS << AP.TM.getRegisterInfo()->getName(MI->getOperand(0).getReg());
}
OS << '+' << MI->getOperand(1).getImm();
// NOTE: Want this comment at start of line, don't emit with AddComment.
AP.OutStreamer.EmitRawText(OS.str());
return true;
}
/// EmitFunctionBody - This method emits the body and trailer for a
/// function.
void AsmPrinter::EmitFunctionBody() {
// Emit target-specific gunk before the function body.
EmitFunctionBodyStart();
bool ShouldPrintDebugScopes = DD && MMI->hasDebugInfo();
// Print out code for the function.
bool HasAnyRealCode = false;
const MachineInstr *LastMI = 0;
for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
I != E; ++I) {
// Print a label for the basic block.
EmitBasicBlockStart(I);
for (MachineBasicBlock::const_iterator II = I->begin(), IE = I->end();
II != IE; ++II) {
LastMI = II;
// Print the assembly for the instruction.
if (!II->isLabel() && !II->isImplicitDef() && !II->isKill() &&
!II->isDebugValue()) {
HasAnyRealCode = true;
++EmittedInsts;
}
if (ShouldPrintDebugScopes) {
NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
DD->beginInstruction(II);
}
if (isVerbose())
EmitComments(*II, OutStreamer.GetCommentOS());
switch (II->getOpcode()) {
case TargetOpcode::PROLOG_LABEL:
case TargetOpcode::EH_LABEL:
case TargetOpcode::GC_LABEL:
OutStreamer.EmitLabel(II->getOperand(0).getMCSymbol());
break;
case TargetOpcode::INLINEASM:
EmitInlineAsm(II);
break;
case TargetOpcode::DBG_VALUE:
if (isVerbose()) {
if (!EmitDebugValueComment(II, *this))
EmitInstruction(II);
}
break;
case TargetOpcode::IMPLICIT_DEF:
if (isVerbose()) EmitImplicitDef(II, *this);
break;
case TargetOpcode::KILL:
if (isVerbose()) EmitKill(II, *this);
break;
default:
EmitInstruction(II);
break;
}
if (ShouldPrintDebugScopes) {
NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
DD->endInstruction(II);
}
}
}
// If the last instruction was a prolog label, then we have a situation where
// we emitted a prolog but no function body. This results in the ending prolog
// label equaling the end of function label and an invalid "row" in the
// FDE. We need to emit a noop in this situation so that the FDE's rows are
// valid.
bool RequiresNoop = LastMI && LastMI->isPrologLabel();
// If the function is empty and the object file uses .subsections_via_symbols,
// then we need to emit *something* to the function body to prevent the
// labels from collapsing together. Just emit a noop.
if ((MAI->hasSubsectionsViaSymbols() && !HasAnyRealCode) || RequiresNoop) {
MCInst Noop;
TM.getInstrInfo()->getNoopForMachoTarget(Noop);
if (Noop.getOpcode()) {
OutStreamer.AddComment("avoids zero-length function");
OutStreamer.EmitInstruction(Noop);
} else // Target not mc-ized yet.
OutStreamer.EmitRawText(StringRef("\tnop\n"));
}
// Emit target-specific gunk after the function body.
EmitFunctionBodyEnd();
// If the target wants a .size directive for the size of the function, emit
// it.
if (MAI->hasDotTypeDotSizeDirective()) {
// Create a symbol for the end of function, so we can get the size as
// difference between the function label and the temp label.
MCSymbol *FnEndLabel = OutContext.CreateTempSymbol();
OutStreamer.EmitLabel(FnEndLabel);
const MCExpr *SizeExp =
MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(FnEndLabel, OutContext),
MCSymbolRefExpr::Create(CurrentFnSym, OutContext),
OutContext);
OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
}
// Emit post-function debug information.
if (DD) {
NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
DD->endFunction(MF);
}
if (DE) {
NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
DE->EndFunction();
}
MMI->EndFunction();
// Print out jump tables referenced by the function.
EmitJumpTableInfo();
OutStreamer.AddBlankLine();
}
/// getDebugValueLocation - Get location information encoded by DBG_VALUE
/// operands.
MachineLocation AsmPrinter::getDebugValueLocation(const MachineInstr *MI) const {
// Target specific DBG_VALUE instructions are handled by each target.
return MachineLocation();
}
bool AsmPrinter::doFinalization(Module &M) {
// Emit global variables.
for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I)
EmitGlobalVariable(I);
// Emit visibility info for declarations
for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
const Function &F = *I;
if (!F.isDeclaration())
continue;
GlobalValue::VisibilityTypes V = F.getVisibility();
if (V == GlobalValue::DefaultVisibility)
continue;
MCSymbol *Name = Mang->getSymbol(&F);
EmitVisibility(Name, V, false);
}
// Finalize debug and EH information.
if (DE) {
{
NamedRegionTimer T(EHTimerName, DWARFGroupName, TimePassesIsEnabled);
DE->EndModule();
}
delete DE; DE = 0;
}
if (DD) {
{
NamedRegionTimer T(DbgTimerName, DWARFGroupName, TimePassesIsEnabled);
DD->endModule();
}
delete DD; DD = 0;
}
// If the target wants to know about weak references, print them all.
if (MAI->getWeakRefDirective()) {
// FIXME: This is not lazy, it would be nice to only print weak references
// to stuff that is actually used. Note that doing so would require targets
// to notice uses in operands (due to constant exprs etc). This should
// happen with the MC stuff eventually.
// Print out module-level global variables here.
for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I) {
if (!I->hasExternalWeakLinkage()) continue;
OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
}
for (Module::const_iterator I = M.begin(), E = M.end(); I != E; ++I) {
if (!I->hasExternalWeakLinkage()) continue;
OutStreamer.EmitSymbolAttribute(Mang->getSymbol(I), MCSA_WeakReference);
}
}
if (MAI->hasSetDirective()) {
OutStreamer.AddBlankLine();
for (Module::const_alias_iterator I = M.alias_begin(), E = M.alias_end();
I != E; ++I) {
MCSymbol *Name = Mang->getSymbol(I);
const GlobalValue *GV = cast<GlobalValue>(I->getAliasedGlobal());
MCSymbol *Target = Mang->getSymbol(GV);
if (I->hasExternalLinkage() || !MAI->getWeakRefDirective())
OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
else if (I->hasWeakLinkage())
OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
else
assert(I->hasLocalLinkage() && "Invalid alias linkage");
EmitVisibility(Name, I->getVisibility());
// Emit the directives as assignments aka .set:
OutStreamer.EmitAssignment(Name,
MCSymbolRefExpr::Create(Target, OutContext));
}
}
GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
assert(MI && "AsmPrinter didn't require GCModuleInfo?");
for (GCModuleInfo::iterator I = MI->end(), E = MI->begin(); I != E; )
if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*--I))
MP->finishAssembly(*this);
// If we don't have any trampolines, then we don't require stack memory
// to be executable. Some targets have a directive to declare this.
Function *InitTrampolineIntrinsic = M.getFunction("llvm.init.trampoline");
if (!InitTrampolineIntrinsic || InitTrampolineIntrinsic->use_empty())
if (const MCSection *S = MAI->getNonexecutableStackSection(OutContext))
OutStreamer.SwitchSection(S);
// Allow the target to emit any magic that it wants at the end of the file,
// after everything else has gone out.
EmitEndOfAsmFile(M);
delete Mang; Mang = 0;
MMI = 0;
OutStreamer.Finish();
return false;
}
void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
this->MF = &MF;
// Get the function symbol.
CurrentFnSym = Mang->getSymbol(MF.getFunction());
if (isVerbose())
LI = &getAnalysis<MachineLoopInfo>();
}
namespace {
// SectionCPs - Keep track the alignment, constpool entries per Section.
struct SectionCPs {
const MCSection *S;
unsigned Alignment;
SmallVector<unsigned, 4> CPEs;
SectionCPs(const MCSection *s, unsigned a) : S(s), Alignment(a) {}
};
}
/// EmitConstantPool - Print to the current output stream assembly
/// representations of the constants in the constant pool MCP. This is
/// used to print out constants which have been "spilled to memory" by
/// the code generator.
///
void AsmPrinter::EmitConstantPool() {
const MachineConstantPool *MCP = MF->getConstantPool();
const std::vector<MachineConstantPoolEntry> &CP = MCP->getConstants();
if (CP.empty()) return;
// Calculate sections for constant pool entries. We collect entries to go into
// the same section together to reduce amount of section switch statements.
SmallVector<SectionCPs, 4> CPSections;
for (unsigned i = 0, e = CP.size(); i != e; ++i) {
const MachineConstantPoolEntry &CPE = CP[i];
unsigned Align = CPE.getAlignment();
SectionKind Kind;
switch (CPE.getRelocationInfo()) {
default: llvm_unreachable("Unknown section kind");
case 2: Kind = SectionKind::getReadOnlyWithRel(); break;
case 1:
Kind = SectionKind::getReadOnlyWithRelLocal();
break;
case 0:
switch (TM.getTargetData()->getTypeAllocSize(CPE.getType())) {
case 4: Kind = SectionKind::getMergeableConst4(); break;
case 8: Kind = SectionKind::getMergeableConst8(); break;
case 16: Kind = SectionKind::getMergeableConst16();break;
default: Kind = SectionKind::getMergeableConst(); break;
}
}
const MCSection *S = getObjFileLowering().getSectionForConstant(Kind);
// The number of sections are small, just do a linear search from the
// last section to the first.
bool Found = false;
unsigned SecIdx = CPSections.size();
while (SecIdx != 0) {
if (CPSections[--SecIdx].S == S) {
Found = true;
break;
}
}
if (!Found) {
SecIdx = CPSections.size();
CPSections.push_back(SectionCPs(S, Align));
}
if (Align > CPSections[SecIdx].Alignment)
CPSections[SecIdx].Alignment = Align;
CPSections[SecIdx].CPEs.push_back(i);
}
// Now print stuff into the calculated sections.
for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
OutStreamer.SwitchSection(CPSections[i].S);
EmitAlignment(Log2_32(CPSections[i].Alignment));
unsigned Offset = 0;
for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
unsigned CPI = CPSections[i].CPEs[j];
MachineConstantPoolEntry CPE = CP[CPI];
// Emit inter-object padding for alignment.
unsigned AlignMask = CPE.getAlignment() - 1;
unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
OutStreamer.EmitFill(NewOffset - Offset, 0/*fillval*/, 0/*addrspace*/);
const Type *Ty = CPE.getType();
Offset = NewOffset + TM.getTargetData()->getTypeAllocSize(Ty);
OutStreamer.EmitLabel(GetCPISymbol(CPI));
if (CPE.isMachineConstantPoolEntry())
EmitMachineConstantPoolValue(CPE.Val.MachineCPVal);
else
EmitGlobalConstant(CPE.Val.ConstVal);
}
}
}
/// EmitJumpTableInfo - Print assembly representations of the jump tables used
/// by the current function to the current output stream.
///
void AsmPrinter::EmitJumpTableInfo() {
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
if (MJTI == 0) return;
if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return;
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
if (JT.empty()) return;
// Pick the directive to use to print the jump table entries, and switch to
// the appropriate section.
const Function *F = MF->getFunction();
bool JTInDiffSection = false;
if (// In PIC mode, we need to emit the jump table to the same section as the
// function body itself, otherwise the label differences won't make sense.
// FIXME: Need a better predicate for this: what about custom entries?
MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
// We should also do if the section name is NULL or function is declared
// in discardable section
// FIXME: this isn't the right predicate, should be based on the MCSection
// for the function.
F->isWeakForLinker()) {
OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F,Mang,TM));
} else {
// Otherwise, drop it in the readonly section.
const MCSection *ReadOnlySection =
getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly());
OutStreamer.SwitchSection(ReadOnlySection);
JTInDiffSection = true;
}
EmitAlignment(Log2_32(MJTI->getEntryAlignment(*TM.getTargetData())));
for (unsigned JTI = 0, e = JT.size(); JTI != e; ++JTI) {
const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
// If this jump table was deleted, ignore it.
if (JTBBs.empty()) continue;
// For the EK_LabelDifference32 entry, if the target supports .set, emit a
// .set directive for each unique entry. This reduces the number of
// relocations the assembler will generate for the jump table.
if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
MAI->hasSetDirective()) {
SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
const TargetLowering *TLI = TM.getTargetLowering();
const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) {
const MachineBasicBlock *MBB = JTBBs[ii];
if (!EmittedSets.insert(MBB)) continue;
// .set LJTSet, LBB32-base
const MCExpr *LHS =
MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
OutStreamer.EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()),
MCBinaryExpr::CreateSub(LHS, Base, OutContext));
}
}
// On some targets (e.g. Darwin) we want to emit two consecutive labels
// before each jump table. The first label is never referenced, but tells
// the assembler and linker the extents of the jump table object. The
// second label is actually referenced by the code.
if (JTInDiffSection && MAI->getLinkerPrivateGlobalPrefix()[0])
// FIXME: This doesn't have to have any specific name, just any randomly
// named and numbered 'l' label would work. Simplify GetJTISymbol.
OutStreamer.EmitLabel(GetJTISymbol(JTI, true));
OutStreamer.EmitLabel(GetJTISymbol(JTI));
for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii)
EmitJumpTableEntry(MJTI, JTBBs[ii], JTI);
}
}
/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the
/// current stream.
void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI,
const MachineBasicBlock *MBB,
unsigned UID) const {
assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block");
const MCExpr *Value = 0;
switch (MJTI->getEntryKind()) {
case MachineJumpTableInfo::EK_Inline:
llvm_unreachable("Cannot emit EK_Inline jump table entry"); break;
case MachineJumpTableInfo::EK_Custom32:
Value = TM.getTargetLowering()->LowerCustomJumpTableEntry(MJTI, MBB, UID,
OutContext);
break;
case MachineJumpTableInfo::EK_BlockAddress:
// EK_BlockAddress - Each entry is a plain address of block, e.g.:
// .word LBB123
Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
break;
case MachineJumpTableInfo::EK_GPRel32BlockAddress: {
// EK_GPRel32BlockAddress - Each entry is an address of block, encoded
// with a relocation as gp-relative, e.g.:
// .gprel32 LBB123
MCSymbol *MBBSym = MBB->getSymbol();
OutStreamer.EmitGPRel32Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
return;
}
case MachineJumpTableInfo::EK_LabelDifference32: {
// EK_LabelDifference32 - Each entry is the address of the block minus
// the address of the jump table. This is used for PIC jump tables where
// gprel32 is not supported. e.g.:
// .word LBB123 - LJTI1_2
// If the .set directive is supported, this is emitted as:
// .set L4_5_set_123, LBB123 - LJTI1_2
// .word L4_5_set_123
// If we have emitted set directives for the jump table entries, print
// them rather than the entries themselves. If we're emitting PIC, then
// emit the table entries as differences between two text section labels.
if (MAI->hasSetDirective()) {
// If we used .set, reference the .set's symbol.
Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
OutContext);
break;
}
// Otherwise, use the difference as the jump table entry.
Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
const MCExpr *JTI = MCSymbolRefExpr::Create(GetJTISymbol(UID), OutContext);
Value = MCBinaryExpr::CreateSub(Value, JTI, OutContext);
break;
}
}
assert(Value && "Unknown entry kind!");
unsigned EntrySize = MJTI->getEntrySize(*TM.getTargetData());
OutStreamer.EmitValue(Value, EntrySize, /*addrspace*/0);
}
/// EmitSpecialLLVMGlobal - Check to see if the specified global is a
/// special global used by LLVM. If so, emit it and return true, otherwise
/// do nothing and return false.
bool AsmPrinter::EmitSpecialLLVMGlobal(const GlobalVariable *GV) {
if (GV->getName() == "llvm.used") {
if (MAI->hasNoDeadStrip()) // No need to emit this at all.
EmitLLVMUsedList(GV->getInitializer());
return true;
}
// Ignore debug and non-emitted data. This handles llvm.compiler.used.
if (GV->getSection() == "llvm.metadata" ||
GV->hasAvailableExternallyLinkage())
return true;
if (!GV->hasAppendingLinkage()) return false;
assert(GV->hasInitializer() && "Not a special LLVM global!");
const TargetData *TD = TM.getTargetData();
unsigned Align = Log2_32(TD->getPointerPrefAlignment());
if (GV->getName() == "llvm.global_ctors") {
OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
EmitAlignment(Align);
EmitXXStructorList(GV->getInitializer());
if (TM.getRelocationModel() == Reloc::Static &&
MAI->hasStaticCtorDtorReferenceInStaticMode()) {
StringRef Sym(".constructors_used");
OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
MCSA_Reference);
}
return true;
}
if (GV->getName() == "llvm.global_dtors") {
OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
EmitAlignment(Align);
EmitXXStructorList(GV->getInitializer());
if (TM.getRelocationModel() == Reloc::Static &&
MAI->hasStaticCtorDtorReferenceInStaticMode()) {
StringRef Sym(".destructors_used");
OutStreamer.EmitSymbolAttribute(OutContext.GetOrCreateSymbol(Sym),
MCSA_Reference);
}
return true;
}
return false;
}
/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
/// global in the specified llvm.used list for which emitUsedDirectiveFor
/// is true, as being used with this directive.
void AsmPrinter::EmitLLVMUsedList(Constant *List) {
// Should be an array of 'i8*'.
ConstantArray *InitList = dyn_cast<ConstantArray>(List);
if (InitList == 0) return;
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
const GlobalValue *GV =
dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
if (GV && getObjFileLowering().shouldEmitUsedDirectiveFor(GV, Mang))
OutStreamer.EmitSymbolAttribute(Mang->getSymbol(GV), MCSA_NoDeadStrip);
}
}
/// EmitXXStructorList - Emit the ctor or dtor list. This just prints out the
/// function pointers, ignoring the init priority.
void AsmPrinter::EmitXXStructorList(Constant *List) {
// Should be an array of '{ int, void ()* }' structs. The first value is the
// init priority, which we ignore.
if (!isa<ConstantArray>(List)) return;
ConstantArray *InitList = cast<ConstantArray>(List);
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
if (ConstantStruct *CS = dyn_cast<ConstantStruct>(InitList->getOperand(i))){
if (CS->getNumOperands() != 2) return; // Not array of 2-element structs.
if (CS->getOperand(1)->isNullValue())
return; // Found a null terminator, exit printing.
// Emit the function pointer.
EmitGlobalConstant(CS->getOperand(1));
}
}
//===--------------------------------------------------------------------===//
// Emission and print routines
//
/// EmitInt8 - Emit a byte directive and value.
///
void AsmPrinter::EmitInt8(int Value) const {
OutStreamer.EmitIntValue(Value, 1, 0/*addrspace*/);
}
/// EmitInt16 - Emit a short directive and value.
///
void AsmPrinter::EmitInt16(int Value) const {
OutStreamer.EmitIntValue(Value, 2, 0/*addrspace*/);
}
/// EmitInt32 - Emit a long directive and value.
///
void AsmPrinter::EmitInt32(int Value) const {
OutStreamer.EmitIntValue(Value, 4, 0/*addrspace*/);
}
/// EmitLabelDifference - Emit something like ".long Hi-Lo" where the size
/// in bytes of the directive is specified by Size and Hi/Lo specify the
/// labels. This implicitly uses .set if it is available.
void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo,
unsigned Size) const {
// Get the Hi-Lo expression.
const MCExpr *Diff =
MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(Hi, OutContext),
MCSymbolRefExpr::Create(Lo, OutContext),
OutContext);
if (!MAI->hasSetDirective()) {
OutStreamer.EmitValue(Diff, Size, 0/*AddrSpace*/);
return;
}
// Otherwise, emit with .set (aka assignment).
MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
OutStreamer.EmitAssignment(SetLabel, Diff);
OutStreamer.EmitSymbolValue(SetLabel, Size, 0/*AddrSpace*/);
}
/// EmitLabelOffsetDifference - Emit something like ".long Hi+Offset-Lo"
/// where the size in bytes of the directive is specified by Size and Hi/Lo
/// specify the labels. This implicitly uses .set if it is available.
void AsmPrinter::EmitLabelOffsetDifference(const MCSymbol *Hi, uint64_t Offset,
const MCSymbol *Lo, unsigned Size)
const {
// Emit Hi+Offset - Lo
// Get the Hi+Offset expression.
const MCExpr *Plus =
MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Hi, OutContext),
MCConstantExpr::Create(Offset, OutContext),
OutContext);
// Get the Hi+Offset-Lo expression.
const MCExpr *Diff =
MCBinaryExpr::CreateSub(Plus,
MCSymbolRefExpr::Create(Lo, OutContext),
OutContext);
if (!MAI->hasSetDirective())
OutStreamer.EmitValue(Diff, 4, 0/*AddrSpace*/);
else {
// Otherwise, emit with .set (aka assignment).
MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
OutStreamer.EmitAssignment(SetLabel, Diff);
OutStreamer.EmitSymbolValue(SetLabel, 4, 0/*AddrSpace*/);
}
}
/// EmitLabelPlusOffset - Emit something like ".long Label+Offset"
/// where the size in bytes of the directive is specified by Size and Label
/// specifies the label. This implicitly uses .set if it is available.
void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset,
unsigned Size)
const {
// Emit Label+Offset
const MCExpr *Plus =
MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Label, OutContext),
MCConstantExpr::Create(Offset, OutContext),
OutContext);
OutStreamer.EmitValue(Plus, 4, 0/*AddrSpace*/);
}
//===----------------------------------------------------------------------===//
// EmitAlignment - Emit an alignment directive to the specified power of
// two boundary. For example, if you pass in 3 here, you will get an 8
// byte alignment. If a global value is specified, and if that global has
// an explicit alignment requested, it will override the alignment request
// if required for correctness.
//
void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getTargetData(), NumBits);
if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
if (getCurrentSection()->getKind().isText())
OutStreamer.EmitCodeAlignment(1 << NumBits);
else
OutStreamer.EmitValueToAlignment(1 << NumBits, 0, 1, 0);
}
//===----------------------------------------------------------------------===//
// Constant emission.
//===----------------------------------------------------------------------===//
/// LowerConstant - Lower the specified LLVM Constant to an MCExpr.
///
static const MCExpr *LowerConstant(const Constant *CV, AsmPrinter &AP) {
MCContext &Ctx = AP.OutContext;
if (CV->isNullValue() || isa<UndefValue>(CV))
return MCConstantExpr::Create(0, Ctx);
if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV))
return MCConstantExpr::Create(CI->getZExtValue(), Ctx);
if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
return MCSymbolRefExpr::Create(AP.Mang->getSymbol(GV), Ctx);
if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
return MCSymbolRefExpr::Create(AP.GetBlockAddressSymbol(BA), Ctx);
const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
if (CE == 0) {
llvm_unreachable("Unknown constant value to lower!");
return MCConstantExpr::Create(0, Ctx);
}
switch (CE->getOpcode()) {
default:
// If the code isn't optimized, there may be outstanding folding
// opportunities. Attempt to fold the expression using TargetData as a
// last resort before giving up.
if (Constant *C =
ConstantFoldConstantExpression(CE, AP.TM.getTargetData()))
if (C != CE)
return LowerConstant(C, AP);
// Otherwise report the problem to the user.
{
std::string S;
raw_string_ostream OS(S);
OS << "Unsupported expression in static initializer: ";
WriteAsOperand(OS, CE, /*PrintType=*/false,
!AP.MF ? 0 : AP.MF->getFunction()->getParent());
report_fatal_error(OS.str());
}
return MCConstantExpr::Create(0, Ctx);
case Instruction::GetElementPtr: {
const TargetData &TD = *AP.TM.getTargetData();
// Generate a symbolic expression for the byte address
const Constant *PtrVal = CE->getOperand(0);
SmallVector<Value*, 8> IdxVec(CE->op_begin()+1, CE->op_end());
int64_t Offset = TD.getIndexedOffset(PtrVal->getType(), &IdxVec[0],
IdxVec.size());
const MCExpr *Base = LowerConstant(CE->getOperand(0), AP);
if (Offset == 0)
return Base;
// Truncate/sext the offset to the pointer size.
if (TD.getPointerSizeInBits() != 64) {
int SExtAmount = 64-TD.getPointerSizeInBits();
Offset = (Offset << SExtAmount) >> SExtAmount;
}
return MCBinaryExpr::CreateAdd(Base, MCConstantExpr::Create(Offset, Ctx),
Ctx);
}
case Instruction::Trunc:
// We emit the value and depend on the assembler to truncate the generated
// expression properly. This is important for differences between
// blockaddress labels. Since the two labels are in the same function, it
// is reasonable to treat their delta as a 32-bit value.
// FALL THROUGH.
case Instruction::BitCast:
return LowerConstant(CE->getOperand(0), AP);
case Instruction::IntToPtr: {
const TargetData &TD = *AP.TM.getTargetData();
// Handle casts to pointers by changing them into casts to the appropriate
// integer type. This promotes constant folding and simplifies this code.
Constant *Op = CE->getOperand(0);
Op = ConstantExpr::getIntegerCast(Op, TD.getIntPtrType(CV->getContext()),
false/*ZExt*/);
return LowerConstant(Op, AP);
}
case Instruction::PtrToInt: {
const TargetData &TD = *AP.TM.getTargetData();
// Support only foldable casts to/from pointers that can be eliminated by
// changing the pointer to the appropriately sized integer type.
Constant *Op = CE->getOperand(0);
const Type *Ty = CE->getType();
const MCExpr *OpExpr = LowerConstant(Op, AP);
// We can emit the pointer value into this slot if the slot is an
// integer slot equal to the size of the pointer.
if (TD.getTypeAllocSize(Ty) == TD.getTypeAllocSize(Op->getType()))
return OpExpr;
// Otherwise the pointer is smaller than the resultant integer, mask off
// the high bits so we are sure to get a proper truncation if the input is
// a constant expr.
unsigned InBits = TD.getTypeAllocSizeInBits(Op->getType());
const MCExpr *MaskExpr = MCConstantExpr::Create(~0ULL >> (64-InBits), Ctx);
return MCBinaryExpr::CreateAnd(OpExpr, MaskExpr, Ctx);
}
// The MC library also has a right-shift operator, but it isn't consistently
// signed or unsigned between different targets.
case Instruction::Add:
case Instruction::Sub:
case Instruction::Mul:
case Instruction::SDiv:
case Instruction::SRem:
case Instruction::Shl:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor: {
const MCExpr *LHS = LowerConstant(CE->getOperand(0), AP);
const MCExpr *RHS = LowerConstant(CE->getOperand(1), AP);
switch (CE->getOpcode()) {
default: llvm_unreachable("Unknown binary operator constant cast expr");
case Instruction::Add: return MCBinaryExpr::CreateAdd(LHS, RHS, Ctx);
case Instruction::Sub: return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
case Instruction::Mul: return MCBinaryExpr::CreateMul(LHS, RHS, Ctx);
case Instruction::SDiv: return MCBinaryExpr::CreateDiv(LHS, RHS, Ctx);
case Instruction::SRem: return MCBinaryExpr::CreateMod(LHS, RHS, Ctx);
case Instruction::Shl: return MCBinaryExpr::CreateShl(LHS, RHS, Ctx);
case Instruction::And: return MCBinaryExpr::CreateAnd(LHS, RHS, Ctx);
case Instruction::Or: return MCBinaryExpr::CreateOr (LHS, RHS, Ctx);
case Instruction::Xor: return MCBinaryExpr::CreateXor(LHS, RHS, Ctx);
}
}
}
}
static void EmitGlobalConstantImpl(const Constant *C, unsigned AddrSpace,
AsmPrinter &AP);
static void EmitGlobalConstantArray(const ConstantArray *CA, unsigned AddrSpace,
AsmPrinter &AP) {
if (AddrSpace != 0 || !CA->isString()) {
// Not a string. Print the values in successive locations
for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
EmitGlobalConstantImpl(CA->getOperand(i), AddrSpace, AP);
return;
}
// Otherwise, it can be emitted as .ascii.
SmallVector<char, 128> TmpVec;
TmpVec.reserve(CA->getNumOperands());
for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i)
TmpVec.push_back(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
AP.OutStreamer.EmitBytes(StringRef(TmpVec.data(), TmpVec.size()), AddrSpace);
}
static void EmitGlobalConstantVector(const ConstantVector *CV,
unsigned AddrSpace, AsmPrinter &AP) {
for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
EmitGlobalConstantImpl(CV->getOperand(i), AddrSpace, AP);
}
static void EmitGlobalConstantStruct(const ConstantStruct *CS,
unsigned AddrSpace, AsmPrinter &AP) {
// Print the fields in successive locations. Pad to align if needed!
const TargetData *TD = AP.TM.getTargetData();
unsigned Size = TD->getTypeAllocSize(CS->getType());
const StructLayout *Layout = TD->getStructLayout(CS->getType());
uint64_t SizeSoFar = 0;
for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
const Constant *Field = CS->getOperand(i);
// Check if padding is needed and insert one or more 0s.
uint64_t FieldSize = TD->getTypeAllocSize(Field->getType());
uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
- Layout->getElementOffset(i)) - FieldSize;
SizeSoFar += FieldSize + PadSize;
// Now print the actual field value.
EmitGlobalConstantImpl(Field, AddrSpace, AP);
// Insert padding - this may include padding to increase the size of the
// current field up to the ABI size (if the struct is not packed) as well
// as padding to ensure that the next field starts at the right offset.
AP.OutStreamer.EmitZeros(PadSize, AddrSpace);
}
assert(SizeSoFar == Layout->getSizeInBytes() &&
"Layout of constant struct may be incorrect!");
}
static void EmitGlobalConstantFP(const ConstantFP *CFP, unsigned AddrSpace,
AsmPrinter &AP) {
// FP Constants are printed as integer constants to avoid losing
// precision.
if (CFP->getType()->isDoubleTy()) {
if (AP.isVerbose()) {
double Val = CFP->getValueAPF().convertToDouble();
AP.OutStreamer.GetCommentOS() << "double " << Val << '\n';
}
uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
return;
}
if (CFP->getType()->isFloatTy()) {
if (AP.isVerbose()) {
float Val = CFP->getValueAPF().convertToFloat();
AP.OutStreamer.GetCommentOS() << "float " << Val << '\n';
}
uint64_t Val = CFP->getValueAPF().bitcastToAPInt().getZExtValue();
AP.OutStreamer.EmitIntValue(Val, 4, AddrSpace);
return;
}
if (CFP->getType()->isX86_FP80Ty()) {
// all long double variants are printed as hex
// API needed to prevent premature destruction
APInt API = CFP->getValueAPF().bitcastToAPInt();
const uint64_t *p = API.getRawData();
if (AP.isVerbose()) {
// Convert to double so we can print the approximate val as a comment.
APFloat DoubleVal = CFP->getValueAPF();
bool ignored;
DoubleVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven,
&ignored);
AP.OutStreamer.GetCommentOS() << "x86_fp80 ~= "
<< DoubleVal.convertToDouble() << '\n';
}
if (AP.TM.getTargetData()->isBigEndian()) {
AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
} else {
AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
AP.OutStreamer.EmitIntValue(p[1], 2, AddrSpace);
}
// Emit the tail padding for the long double.
const TargetData &TD = *AP.TM.getTargetData();
AP.OutStreamer.EmitZeros(TD.getTypeAllocSize(CFP->getType()) -
TD.getTypeStoreSize(CFP->getType()), AddrSpace);
return;
}
assert(CFP->getType()->isPPC_FP128Ty() &&
"Floating point constant type not handled");
// All long double variants are printed as hex
// API needed to prevent premature destruction.
APInt API = CFP->getValueAPF().bitcastToAPInt();
const uint64_t *p = API.getRawData();
if (AP.TM.getTargetData()->isBigEndian()) {
AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
} else {
AP.OutStreamer.EmitIntValue(p[1], 8, AddrSpace);
AP.OutStreamer.EmitIntValue(p[0], 8, AddrSpace);
}
}
static void EmitGlobalConstantLargeInt(const ConstantInt *CI,
unsigned AddrSpace, AsmPrinter &AP) {
const TargetData *TD = AP.TM.getTargetData();
unsigned BitWidth = CI->getBitWidth();
assert((BitWidth & 63) == 0 && "only support multiples of 64-bits");
// We don't expect assemblers to support integer data directives
// for more than 64 bits, so we emit the data in at most 64-bit
// quantities at a time.
const uint64_t *RawData = CI->getValue().getRawData();
for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
uint64_t Val = TD->isBigEndian() ? RawData[e - i - 1] : RawData[i];
AP.OutStreamer.EmitIntValue(Val, 8, AddrSpace);
}
}
static void EmitGlobalConstantImpl(const Constant *CV, unsigned AddrSpace,
AsmPrinter &AP) {
if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) {
uint64_t Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
return AP.OutStreamer.EmitZeros(Size, AddrSpace);
}
if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
switch (Size) {
case 1:
case 2:
case 4:
case 8:
if (AP.isVerbose())
AP.OutStreamer.GetCommentOS() << format("0x%llx\n", CI->getZExtValue());
AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size, AddrSpace);
return;
default:
EmitGlobalConstantLargeInt(CI, AddrSpace, AP);
return;
}
}
if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
return EmitGlobalConstantArray(CVA, AddrSpace, AP);
if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
return EmitGlobalConstantStruct(CVS, AddrSpace, AP);
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
return EmitGlobalConstantFP(CFP, AddrSpace, AP);
if (isa<ConstantPointerNull>(CV)) {
unsigned Size = AP.TM.getTargetData()->getTypeAllocSize(CV->getType());
AP.OutStreamer.EmitIntValue(0, Size, AddrSpace);
return;
}
if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
return EmitGlobalConstantVector(V, AddrSpace, AP);
// Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
// thread the streamer with EmitValue.
AP.OutStreamer.EmitValue(LowerConstant(CV, AP),
AP.TM.getTargetData()->getTypeAllocSize(CV->getType()),
AddrSpace);
}
/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
void AsmPrinter::EmitGlobalConstant(const Constant *CV, unsigned AddrSpace) {
uint64_t Size = TM.getTargetData()->getTypeAllocSize(CV->getType());
if (Size)
EmitGlobalConstantImpl(CV, AddrSpace, *this);
else if (MAI->hasSubsectionsViaSymbols()) {
// If the global has zero size, emit a single byte so that two labels don't
// look like they are at the same location.
OutStreamer.EmitIntValue(0, 1, AddrSpace);
}
}
void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) {
// Target doesn't support this yet!
llvm_unreachable("Target does not support EmitMachineConstantPoolValue");
}
void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const {
if (Offset > 0)
OS << '+' << Offset;
else if (Offset < 0)
OS << Offset;
}
//===----------------------------------------------------------------------===//
// Symbol Lowering Routines.
//===----------------------------------------------------------------------===//
/// GetTempSymbol - Return the MCSymbol corresponding to the assembler
/// temporary label with the specified stem and unique ID.
MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name, unsigned ID) const {
return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
Name + Twine(ID));
}
/// GetTempSymbol - Return an assembler temporary label with the specified
/// stem.
MCSymbol *AsmPrinter::GetTempSymbol(StringRef Name) const {
return OutContext.GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix())+
Name);
}
MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const {
return MMI->getAddrLabelSymbol(BA->getBasicBlock());
}
MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const {
return MMI->getAddrLabelSymbol(BB);
}
/// GetCPISymbol - Return the symbol for the specified constant pool entry.
MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const {
return OutContext.GetOrCreateSymbol
(Twine(MAI->getPrivateGlobalPrefix()) + "CPI" + Twine(getFunctionNumber())
+ "_" + Twine(CPID));
}
/// GetJTISymbol - Return the symbol for the specified jump table entry.
MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const {
return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate);
}
/// GetJTSetSymbol - Return the symbol for the specified jump table .set
/// FIXME: privatize to AsmPrinter.
MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const {
return OutContext.GetOrCreateSymbol
(Twine(MAI->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
Twine(UID) + "_set_" + Twine(MBBID));
}
/// GetSymbolWithGlobalValueBase - Return the MCSymbol for a symbol with
/// global value name as its base, with the specified suffix, and where the
/// symbol is forced to have private linkage if ForcePrivate is true.
MCSymbol *AsmPrinter::GetSymbolWithGlobalValueBase(const GlobalValue *GV,
StringRef Suffix,
bool ForcePrivate) const {
SmallString<60> NameStr;
Mang->getNameWithPrefix(NameStr, GV, ForcePrivate);
NameStr.append(Suffix.begin(), Suffix.end());
return OutContext.GetOrCreateSymbol(NameStr.str());
}
/// GetExternalSymbolSymbol - Return the MCSymbol for the specified
/// ExternalSymbol.
MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const {
SmallString<60> NameStr;
Mang->getNameWithPrefix(NameStr, Sym);
return OutContext.GetOrCreateSymbol(NameStr.str());
}
/// PrintParentLoopComment - Print comments about parent loops of this one.
static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop,
unsigned FunctionNumber) {
if (Loop == 0) return;
PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber);
OS.indent(Loop->getLoopDepth()*2)
<< "Parent Loop BB" << FunctionNumber << "_"
<< Loop->getHeader()->getNumber()
<< " Depth=" << Loop->getLoopDepth() << '\n';
}
/// PrintChildLoopComment - Print comments about child loops within
/// the loop for this basic block, with nesting.
static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop,
unsigned FunctionNumber) {
// Add child loop information
for (MachineLoop::iterator CL = Loop->begin(), E = Loop->end();CL != E; ++CL){
OS.indent((*CL)->getLoopDepth()*2)
<< "Child Loop BB" << FunctionNumber << "_"
<< (*CL)->getHeader()->getNumber() << " Depth " << (*CL)->getLoopDepth()
<< '\n';
PrintChildLoopComment(OS, *CL, FunctionNumber);
}
}
/// EmitBasicBlockLoopComments - Pretty-print comments for basic blocks.
static void EmitBasicBlockLoopComments(const MachineBasicBlock &MBB,
const MachineLoopInfo *LI,
const AsmPrinter &AP) {
// Add loop depth information
const MachineLoop *Loop = LI->getLoopFor(&MBB);
if (Loop == 0) return;
MachineBasicBlock *Header = Loop->getHeader();
assert(Header && "No header for loop");
// If this block is not a loop header, just print out what is the loop header
// and return.
if (Header != &MBB) {
AP.OutStreamer.AddComment(" in Loop: Header=BB" +
Twine(AP.getFunctionNumber())+"_" +
Twine(Loop->getHeader()->getNumber())+
" Depth="+Twine(Loop->getLoopDepth()));
return;
}
// Otherwise, it is a loop header. Print out information about child and
// parent loops.
raw_ostream &OS = AP.OutStreamer.GetCommentOS();
PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber());
OS << "=>";
OS.indent(Loop->getLoopDepth()*2-2);
OS << "This ";
if (Loop->empty())
OS << "Inner ";
OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n';
PrintChildLoopComment(OS, Loop, AP.getFunctionNumber());
}
/// EmitBasicBlockStart - This method prints the label for the specified
/// MachineBasicBlock, an alignment (if present) and a comment describing
/// it if appropriate.
void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock *MBB) const {
// Emit an alignment directive for this block, if needed.
if (unsigned Align = MBB->getAlignment())
EmitAlignment(Log2_32(Align));
// If the block has its address taken, emit any labels that were used to
// reference the block. It is possible that there is more than one label
// here, because multiple LLVM BB's may have been RAUW'd to this block after
// the references were generated.
if (MBB->hasAddressTaken()) {
const BasicBlock *BB = MBB->getBasicBlock();
if (isVerbose())
OutStreamer.AddComment("Block address taken");
std::vector<MCSymbol*> Syms = MMI->getAddrLabelSymbolToEmit(BB);
for (unsigned i = 0, e = Syms.size(); i != e; ++i)
OutStreamer.EmitLabel(Syms[i]);
}
// Print the main label for the block.
if (MBB->pred_empty() || isBlockOnlyReachableByFallthrough(MBB)) {
if (isVerbose() && OutStreamer.hasRawTextSupport()) {
if (const BasicBlock *BB = MBB->getBasicBlock())
if (BB->hasName())
OutStreamer.AddComment("%" + BB->getName());
EmitBasicBlockLoopComments(*MBB, LI, *this);
// NOTE: Want this comment at start of line, don't emit with AddComment.
OutStreamer.EmitRawText(Twine(MAI->getCommentString()) + " BB#" +
Twine(MBB->getNumber()) + ":");
}
} else {
if (isVerbose()) {
if (const BasicBlock *BB = MBB->getBasicBlock())
if (BB->hasName())
OutStreamer.AddComment("%" + BB->getName());
EmitBasicBlockLoopComments(*MBB, LI, *this);
}
OutStreamer.EmitLabel(MBB->getSymbol());
}
}
void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility,
bool IsDefinition) const {
MCSymbolAttr Attr = MCSA_Invalid;
switch (Visibility) {
default: break;
case GlobalValue::HiddenVisibility:
if (IsDefinition)
Attr = MAI->getHiddenVisibilityAttr();
else
Attr = MAI->getHiddenDeclarationVisibilityAttr();
break;
case GlobalValue::ProtectedVisibility:
Attr = MAI->getProtectedVisibilityAttr();
break;
}
if (Attr != MCSA_Invalid)
OutStreamer.EmitSymbolAttribute(Sym, Attr);
}
/// isBlockOnlyReachableByFallthough - Return true if the basic block has
/// exactly one predecessor and the control transfer mechanism between
/// the predecessor and this block is a fall-through.
bool AsmPrinter::
isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const {
// If this is a landing pad, it isn't a fall through. If it has no preds,
// then nothing falls through to it.
if (MBB->isLandingPad() || MBB->pred_empty())
return false;
// If there isn't exactly one predecessor, it can't be a fall through.
MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
++PI2;
if (PI2 != MBB->pred_end())
return false;
// The predecessor has to be immediately before this block.
const MachineBasicBlock *Pred = *PI;
if (!Pred->isLayoutSuccessor(MBB))
return false;
// If the block is completely empty, then it definitely does fall through.
if (Pred->empty())
return true;
// Otherwise, check the last instruction.
const MachineInstr &LastInst = Pred->back();
return !LastInst.getDesc().isBarrier();
}
GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy *S) {
if (!S->usesMetadata())
return 0;
gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
gcp_map_type::iterator GCPI = GCMap.find(S);
if (GCPI != GCMap.end())
return GCPI->second;
const char *Name = S->getName().c_str();
for (GCMetadataPrinterRegistry::iterator
I = GCMetadataPrinterRegistry::begin(),
E = GCMetadataPrinterRegistry::end(); I != E; ++I)
if (strcmp(Name, I->getName()) == 0) {
GCMetadataPrinter *GMP = I->instantiate();
GMP->S = S;
GCMap.insert(std::make_pair(S, GMP));
return GMP;
}
report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
return 0;
}
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