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llvm-6502/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
Rafael Espindola be886690bd Print jump tables before exception tables. 
In the case where just tables are part of the function section, this produces
more readable assembly by avoiding switching to the eh section and back
to .text.

This would also break with non unique section names, as trying to switch to
a unique section actually creates a new one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231677 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-09 18:29:12 +00:00

2512 lines
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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.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/AsmPrinter.h"
#include "DwarfDebug.h"
#include "DwarfException.h"
#include "Win64Exception.h"
#include "WinCodeViewLineTables.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/JumpInstrTableInfo.h"
#include "llvm/CodeGen/Analysis.h"
#include "llvm/CodeGen/GCMetadataPrinter.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBundle.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.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/MC/MCValue.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/Timer.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
using namespace llvm;
#define DEBUG_TYPE "asm-printer"
static const char *const DWARFGroupName = "DWARF Emission";
static const char *const DbgTimerName = "Debug Info Emission";
static const char *const EHTimerName = "DWARF Exception Writer";
static const char *const CodeViewLineTablesGroupName = "CodeView Line Tables";
STATISTIC(EmittedInsts, "Number of machine instrs printed");
char AsmPrinter::ID = 0;
typedef DenseMap<GCStrategy*, std::unique_ptr<GCMetadataPrinter>> gcp_map_type;
static gcp_map_type &getGCMap(void *&P) {
if (!P)
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 DataLayout &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, std::unique_ptr<MCStreamer> Streamer)
: MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
OutContext(Streamer->getContext()), OutStreamer(*Streamer.release()),
LastMI(nullptr), LastFn(0), Counter(~0U), SetCounter(0) {
DD = nullptr;
MMI = nullptr;
LI = nullptr;
MF = nullptr;
CurrentFnSym = CurrentFnSymForSize = nullptr;
CurrentFnBegin = nullptr;
CurrentFnEnd = nullptr;
GCMetadataPrinters = nullptr;
VerboseAsm = OutStreamer.isVerboseAsm();
}
AsmPrinter::~AsmPrinter() {
assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized");
if (GCMetadataPrinters) {
gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
delete &GCMap;
GCMetadataPrinters = nullptr;
}
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.getObjFileLowering();
}
/// getDataLayout - Return information about data layout.
const DataLayout &AsmPrinter::getDataLayout() const {
return *TM.getDataLayout();
}
const MCSubtargetInfo &AsmPrinter::getSubtargetInfo() const {
assert(MF && "getSubtargetInfo requires a valid MachineFunction!");
return MF->getSubtarget<MCSubtargetInfo>();
}
void AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
S.EmitInstruction(Inst, getSubtargetInfo());
}
StringRef AsmPrinter::getTargetTriple() const {
return TM.getTargetTriple();
}
/// getCurrentSection() - Return the current section we are emitting to.
const MCSection *AsmPrinter::getCurrentSection() const {
return OutStreamer.getCurrentSection().first;
}
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);
OutStreamer.InitSections(false);
Mang = new Mangler(TM.getDataLayout());
// Emit the version-min deplyment target directive if needed.
//
// FIXME: If we end up with a collection of these sorts of Darwin-specific
// or ELF-specific things, it may make sense to have a platform helper class
// that will work with the target helper class. For now keep it here, as the
// alternative is duplicated code in each of the target asm printers that
// use the directive, where it would need the same conditionalization
// anyway.
Triple TT(getTargetTriple());
if (TT.isOSDarwin()) {
unsigned Major, Minor, Update;
TT.getOSVersion(Major, Minor, Update);
// If there is a version specified, Major will be non-zero.
if (Major)
OutStreamer.EmitVersionMin((TT.isMacOSX() ?
MCVM_OSXVersionMin : MCVM_IOSVersionMin),
Major, Minor, Update);
}
// 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 (auto &I : *MI)
if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I))
MP->beginAssembly(M, *MI, *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()) {
bool skip_dwarf = false;
if (Triple(TM.getTargetTriple()).isKnownWindowsMSVCEnvironment()) {
Handlers.push_back(HandlerInfo(new WinCodeViewLineTables(this),
DbgTimerName,
CodeViewLineTablesGroupName));
// FIXME: Don't emit DWARF debug info if there's at least one function
// with AddressSanitizer instrumentation.
// This is a band-aid fix for PR22032.
for (auto &F : M.functions()) {
if (F.hasFnAttribute(Attribute::SanitizeAddress)) {
skip_dwarf = true;
break;
}
}
}
if (!skip_dwarf) {
DD = new DwarfDebug(this, &M);
Handlers.push_back(HandlerInfo(DD, DbgTimerName, DWARFGroupName));
}
}
EHStreamer *ES = nullptr;
switch (MAI->getExceptionHandlingType()) {
case ExceptionHandling::None:
break;
case ExceptionHandling::SjLj:
case ExceptionHandling::DwarfCFI:
ES = new DwarfCFIException(this);
break;
case ExceptionHandling::ARM:
ES = new ARMException(this);
break;
case ExceptionHandling::WinEH:
switch (MAI->getWinEHEncodingType()) {
default: llvm_unreachable("unsupported unwinding information encoding");
case WinEH::EncodingType::Itanium:
ES = new Win64Exception(this);
break;
}
break;
}
if (ES)
Handlers.push_back(HandlerInfo(ES, EHTimerName, DWARFGroupName));
return false;
}
static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
if (!MAI.hasWeakDefCanBeHiddenDirective())
return false;
return canBeOmittedFromSymbolTable(GV);
}
void AsmPrinter::EmitLinkage(const GlobalValue *GV, MCSymbol *GVSym) const {
GlobalValue::LinkageTypes Linkage = GV->getLinkage();
switch (Linkage) {
case GlobalValue::CommonLinkage:
case GlobalValue::LinkOnceAnyLinkage:
case GlobalValue::LinkOnceODRLinkage:
case GlobalValue::WeakAnyLinkage:
case GlobalValue::WeakODRLinkage:
if (MAI->hasWeakDefDirective()) {
// .globl _foo
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
if (!canBeHidden(GV, *MAI))
// .weak_definition _foo
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
else
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
} else if (MAI->hasLinkOnceDirective()) {
// .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);
}
return;
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);
return;
case GlobalValue::PrivateLinkage:
case GlobalValue::InternalLinkage:
return;
case GlobalValue::AvailableExternallyLinkage:
llvm_unreachable("Should never emit this");
case GlobalValue::ExternalWeakLinkage:
llvm_unreachable("Don't know how to emit these");
}
llvm_unreachable("Unknown linkage type!");
}
void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
const GlobalValue *GV) const {
TM.getNameWithPrefix(Name, GV, *Mang);
}
MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
return TM.getSymbol(GV, *Mang);
}
/// EmitGlobalVariable - Emit the specified global variable to the .s file.
void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
if (GV->hasInitializer()) {
// Check to see if this is a special global used by LLVM, if so, emit it.
if (EmitSpecialLLVMGlobal(GV))
return;
// Skip the emission of global equivalents. The symbol can be emitted later
// on by emitGlobalGOTEquivs in case it turns out to be needed.
if (GlobalGOTEquivs.count(getSymbol(GV)))
return;
if (isVerbose()) {
GV->printAsOperand(OutStreamer.GetCommentOS(),
/*PrintType=*/false, GV->getParent());
OutStreamer.GetCommentOS() << '\n';
}
}
MCSymbol *GVSym = getSymbol(GV);
EmitVisibility(GVSym, GV->getVisibility(), !GV->isDeclaration());
if (!GV->hasInitializer()) // External globals require no extra code.
return;
GVSym->redefineIfPossible();
if (GVSym->isDefined() || GVSym->isVariable())
report_fatal_error("symbol '" + Twine(GVSym->getName()) +
"' is already defined");
if (MAI->hasDotTypeDotSizeDirective())
OutStreamer.EmitSymbolAttribute(GVSym, MCSA_ELF_TypeObject);
SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
const DataLayout *DL = TM.getDataLayout();
uint64_t Size = DL->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, *DL);
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
HI.Handler->setSymbolSize(GVSym, Size);
}
// Handle common and BSS local symbols (.lcomm).
if (GVKind.isCommon() || GVKind.isBSSLocal()) {
if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
unsigned Align = 1 << AlignLog;
// Handle common symbols.
if (GVKind.isCommon()) {
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, Align);
return;
}
// Use .lcomm only if it supports user-specified alignment.
// Otherwise, while it would still be correct to use .lcomm in some
// cases (e.g. when Align == 1), the external assembler might enfore
// some -unknown- default alignment behavior, which could cause
// spurious differences between external and integrated assembler.
// Prefer to simply fall back to .local / .comm in this case.
if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
// .lcomm _foo, 42
OutStreamer.EmitLocalCommonSymbol(GVSym, Size, Align);
return;
}
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()) {
TheSection = getObjFileLowering().getTLSBSSSection();
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, 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 = DL->getPointerTypeSize(GV->getType());
OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("_tlv_bootstrap"),
PtrSize);
OutStreamer.EmitIntValue(0, PtrSize);
OutStreamer.EmitSymbolValue(MangSym, PtrSize);
OutStreamer.AddBlankLine();
return;
}
OutStreamer.SwitchSection(TheSection);
EmitLinkage(GV, 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, CurrentFnSym);
EmitAlignment(MF->getAlignment(), F);
if (MAI->hasDotTypeDotSizeDirective())
OutStreamer.EmitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
if (isVerbose()) {
F->printAsOperand(OutStreamer.GetCommentOS(),
/*PrintType=*/false, F->getParent());
OutStreamer.GetCommentOS() << '\n';
}
// Emit the prefix data.
if (F->hasPrefixData())
EmitGlobalConstant(F->getPrefixData());
// 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]);
}
if (CurrentFnBegin) {
if (MAI->useAssignmentForEHBegin()) {
MCSymbol *CurPos = OutContext.CreateTempSymbol();
OutStreamer.EmitLabel(CurPos);
OutStreamer.EmitAssignment(CurrentFnBegin,
MCSymbolRefExpr::Create(CurPos, OutContext));
} else {
OutStreamer.EmitLabel(CurrentFnBegin);
}
}
// Emit pre-function debug and/or EH information.
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
HI.Handler->beginFunction(MF);
}
// Emit the prologue data.
if (F->hasPrologueData())
EmitGlobalConstant(F->getPrologueData());
}
/// 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() {
CurrentFnSym->redefineIfPossible();
// 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->isVariable())
report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
"' is a protected alias");
if (CurrentFnSym->isDefined())
report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
"' label emitted multiple times to assembly file");
return OutStreamer.EmitLabel(CurrentFnSym);
}
/// emitComments - Pretty-print comments for instructions.
static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
const MachineFunction *MF = MI.getParent()->getParent();
const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
// 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 (TII->isLoadFromStackSlotPostFE(&MI, FI)) {
if (FrameInfo->isSpillSlotObjectIndex(FI)) {
MMO = *MI.memoperands_begin();
CommentOS << MMO->getSize() << "-byte Reload\n";
}
} else if (TII->hasLoadFromStackSlot(&MI, MMO, FI)) {
if (FrameInfo->isSpillSlotObjectIndex(FI))
CommentOS << MMO->getSize() << "-byte Folded Reload\n";
} else if (TII->isStoreToStackSlotPostFE(&MI, FI)) {
if (FrameInfo->isSpillSlotObjectIndex(FI)) {
MMO = *MI.memoperands_begin();
CommentOS << MMO->getSize() << "-byte Spill\n";
}
} else if (TII->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.
void AsmPrinter::emitImplicitDef(const MachineInstr *MI) const {
unsigned RegNo = MI->getOperand(0).getReg();
OutStreamer.AddComment(Twine("implicit-def: ") +
MMI->getContext().getRegisterInfo()->getName(RegNo));
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.MMI->getContext().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 4-operand target-independent form.
if (MI->getNumOperands() != 4)
return false;
SmallString<128> Str;
raw_svector_ostream OS(Str);
OS << "DEBUG_VALUE: ";
DIVariable V = MI->getDebugVariable();
if (V.getContext().isSubprogram()) {
StringRef Name = DISubprogram(V.getContext()).getDisplayName();
if (!Name.empty())
OS << Name << ":";
}
OS << V.getName();
DIExpression Expr = MI->getDebugExpression();
if (Expr.isBitPiece())
OS << " [bit_piece offset=" << Expr.getBitPieceOffset()
<< " size=" << Expr.getBitPieceSize() << "]";
OS << " <- ";
// The second operand is only an offset if it's an immediate.
bool Deref = MI->getOperand(0).isReg() && MI->getOperand(1).isImm();
int64_t Offset = Deref ? MI->getOperand(1).getImm() : 0;
// 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 if (MI->getOperand(0).isCImm()) {
MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
} else {
unsigned Reg;
if (MI->getOperand(0).isReg()) {
Reg = MI->getOperand(0).getReg();
} else {
assert(MI->getOperand(0).isFI() && "Unknown operand type");
const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
Offset += TFI->getFrameIndexReference(*AP.MF,
MI->getOperand(0).getIndex(), Reg);
Deref = true;
}
if (Reg == 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.emitRawComment(OS.str());
return true;
}
if (Deref)
OS << '[';
OS << AP.MMI->getContext().getRegisterInfo()->getName(Reg);
}
if (Deref)
OS << '+' << Offset << ']';
// NOTE: Want this comment at start of line, don't emit with AddComment.
AP.OutStreamer.emitRawComment(OS.str());
return true;
}
AsmPrinter::CFIMoveType AsmPrinter::needsCFIMoves() {
if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
MF->getFunction()->needsUnwindTableEntry())
return CFI_M_EH;
if (MMI->hasDebugInfo())
return CFI_M_Debug;
return CFI_M_None;
}
bool AsmPrinter::needsSEHMoves() {
return MAI->usesWindowsCFI() && MF->getFunction()->needsUnwindTableEntry();
}
void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
ExceptionHandlingType != ExceptionHandling::ARM)
return;
if (needsCFIMoves() == CFI_M_None)
return;
const MachineModuleInfo &MMI = MF->getMMI();
const std::vector<MCCFIInstruction> &Instrs = MMI.getFrameInstructions();
unsigned CFIIndex = MI.getOperand(0).getCFIIndex();
const MCCFIInstruction &CFI = Instrs[CFIIndex];
emitCFIInstruction(CFI);
}
void AsmPrinter::emitFrameAlloc(const MachineInstr &MI) {
// The operands are the MCSymbol and the frame offset of the allocation.
MCSymbol *FrameAllocSym = MI.getOperand(0).getMCSymbol();
int FrameOffset = MI.getOperand(1).getImm();
// Emit a symbol assignment.
OutStreamer.EmitAssignment(FrameAllocSym,
MCConstantExpr::Create(FrameOffset, OutContext));
}
/// 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 = MMI->hasDebugInfo();
// Print out code for the function.
bool HasAnyRealCode = false;
for (auto &MBB : *MF) {
// Print a label for the basic block.
EmitBasicBlockStart(MBB);
for (auto &MI : MBB) {
// Print the assembly for the instruction.
if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
!MI.isDebugValue()) {
HasAnyRealCode = true;
++EmittedInsts;
}
if (ShouldPrintDebugScopes) {
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
TimePassesIsEnabled);
HI.Handler->beginInstruction(&MI);
}
}
if (isVerbose())
emitComments(MI, OutStreamer.GetCommentOS());
switch (MI.getOpcode()) {
case TargetOpcode::CFI_INSTRUCTION:
emitCFIInstruction(MI);
break;
case TargetOpcode::FRAME_ALLOC:
emitFrameAlloc(MI);
break;
case TargetOpcode::EH_LABEL:
case TargetOpcode::GC_LABEL:
OutStreamer.EmitLabel(MI.getOperand(0).getMCSymbol());
break;
case TargetOpcode::INLINEASM:
EmitInlineAsm(&MI);
break;
case TargetOpcode::DBG_VALUE:
if (isVerbose()) {
if (!emitDebugValueComment(&MI, *this))
EmitInstruction(&MI);
}
break;
case TargetOpcode::IMPLICIT_DEF:
if (isVerbose()) emitImplicitDef(&MI);
break;
case TargetOpcode::KILL:
if (isVerbose()) emitKill(&MI, *this);
break;
default:
EmitInstruction(&MI);
break;
}
if (ShouldPrintDebugScopes) {
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
TimePassesIsEnabled);
HI.Handler->endInstruction();
}
}
}
EmitBasicBlockEnd(MBB);
}
// 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)) {
MCInst Noop;
MF->getSubtarget().getInstrInfo()->getNoopForMachoTarget(Noop);
OutStreamer.AddComment("avoids zero-length function");
// Targets can opt-out of emitting the noop here by leaving the opcode
// unspecified.
if (Noop.getOpcode())
OutStreamer.EmitInstruction(Noop, getSubtargetInfo());
}
const Function *F = MF->getFunction();
for (const auto &BB : *F) {
if (!BB.hasAddressTaken())
continue;
MCSymbol *Sym = GetBlockAddressSymbol(&BB);
if (Sym->isDefined())
continue;
OutStreamer.AddComment("Address of block that was removed by CodeGen");
OutStreamer.EmitLabel(Sym);
}
// Emit target-specific gunk after the function body.
EmitFunctionBodyEnd();
if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
MAI->hasDotTypeDotSizeDirective()) {
// Create a symbol for the end of function.
CurrentFnEnd = createTempSymbol("func_end", getFunctionNumber());
OutStreamer.EmitLabel(CurrentFnEnd);
}
// If the target wants a .size directive for the size of the function, emit
// it.
if (MAI->hasDotTypeDotSizeDirective()) {
// We can get the size as difference between the function label and the
// temp label.
const MCExpr *SizeExp =
MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(CurrentFnEnd, OutContext),
MCSymbolRefExpr::Create(CurrentFnSymForSize,
OutContext),
OutContext);
OutStreamer.EmitELFSize(CurrentFnSym, SizeExp);
}
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
HI.Handler->markFunctionEnd();
}
// Print out jump tables referenced by the function.
EmitJumpTableInfo();
// Emit post-function debug and/or EH information.
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerGroupName, TimePassesIsEnabled);
HI.Handler->endFunction(MF);
}
MMI->EndFunction();
OutStreamer.AddBlankLine();
}
/// \brief Compute the number of Global Variables that uses a Constant.
static unsigned getNumGlobalVariableUses(const Constant *C) {
if (!C)
return 0;
if (isa<GlobalVariable>(C))
return 1;
unsigned NumUses = 0;
for (auto *CU : C->users())
NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
return NumUses;
}
/// \brief Only consider global GOT equivalents if at least one user is a
/// cstexpr inside an initializer of another global variables. Also, don't
/// handle cstexpr inside instructions. During global variable emission,
/// candidates are skipped and are emitted later in case at least one cstexpr
/// isn't replaced by a PC relative GOT entry access.
static bool isGOTEquivalentCandidate(const GlobalVariable *GV,
unsigned &NumGOTEquivUsers) {
// Global GOT equivalents are unnamed private globals with a constant
// pointer initializer to another global symbol. They must point to a
// GlobalVariable or Function, i.e., as GlobalValue.
if (!GV->hasUnnamedAddr() || !GV->hasInitializer() || !GV->isConstant() ||
!GV->isDiscardableIfUnused() || !dyn_cast<GlobalValue>(GV->getOperand(0)))
return false;
// To be a got equivalent, at least one of its users need to be a constant
// expression used by another global variable.
for (auto *U : GV->users())
NumGOTEquivUsers += getNumGlobalVariableUses(cast<Constant>(U));
return NumGOTEquivUsers > 0;
}
/// \brief Unnamed constant global variables solely contaning a pointer to
/// another globals variable is equivalent to a GOT table entry; it contains the
/// the address of another symbol. Optimize it and replace accesses to these
/// "GOT equivalents" by using the GOT entry for the final global instead.
/// Compute GOT equivalent candidates among all global variables to avoid
/// emitting them if possible later on, after it use is replaced by a GOT entry
/// access.
void AsmPrinter::computeGlobalGOTEquivs(Module &M) {
if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
return;
for (const auto &G : M.globals()) {
unsigned NumGOTEquivUsers = 0;
if (!isGOTEquivalentCandidate(&G, NumGOTEquivUsers))
continue;
const MCSymbol *GOTEquivSym = getSymbol(&G);
GlobalGOTEquivs[GOTEquivSym] = std::make_pair(&G, NumGOTEquivUsers);
}
}
/// \brief Constant expressions using GOT equivalent globals may not be eligible
/// for PC relative GOT entry conversion, in such cases we need to emit such
/// globals we previously omitted in EmitGlobalVariable.
void AsmPrinter::emitGlobalGOTEquivs() {
if (!getObjFileLowering().supportIndirectSymViaGOTPCRel())
return;
while (!GlobalGOTEquivs.empty()) {
DenseMap<const MCSymbol *, GOTEquivUsePair>::iterator I =
GlobalGOTEquivs.begin();
const MCSymbol *S = I->first;
const GlobalVariable *GV = I->second.first;
GlobalGOTEquivs.erase(S);
EmitGlobalVariable(GV);
}
}
bool AsmPrinter::doFinalization(Module &M) {
// Gather all GOT equivalent globals in the module. We really need two
// passes over the globals: one to compute and another to avoid its emission
// in EmitGlobalVariable, otherwise we would not be able to handle cases
// where the got equivalent shows up before its use.
computeGlobalGOTEquivs(M);
// Emit global variables.
for (const auto &G : M.globals())
EmitGlobalVariable(&G);
// Emit remaining GOT equivalent globals.
emitGlobalGOTEquivs();
// Emit visibility info for declarations
for (const Function &F : M) {
if (!F.isDeclaration())
continue;
GlobalValue::VisibilityTypes V = F.getVisibility();
if (V == GlobalValue::DefaultVisibility)
continue;
MCSymbol *Name = getSymbol(&F);
EmitVisibility(Name, V, false);
}
// Emit module flags.
SmallVector<Module::ModuleFlagEntry, 8> ModuleFlags;
M.getModuleFlagsMetadata(ModuleFlags);
if (!ModuleFlags.empty())
getObjFileLowering().emitModuleFlags(OutStreamer, ModuleFlags, *Mang, TM);
// Make sure we wrote out everything we need.
OutStreamer.Flush();
// Finalize debug and EH information.
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerGroupName,
TimePassesIsEnabled);
HI.Handler->endModule();
delete HI.Handler;
}
Handlers.clear();
DD = nullptr;
// 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 (const auto &G : M.globals()) {
if (!G.hasExternalWeakLinkage())
continue;
OutStreamer.EmitSymbolAttribute(getSymbol(&G), MCSA_WeakReference);
}
for (const auto &F : M) {
if (!F.hasExternalWeakLinkage())
continue;
OutStreamer.EmitSymbolAttribute(getSymbol(&F), MCSA_WeakReference);
}
}
OutStreamer.AddBlankLine();
for (const auto &Alias : M.aliases()) {
MCSymbol *Name = getSymbol(&Alias);
if (Alias.hasExternalLinkage() || !MAI->getWeakRefDirective())
OutStreamer.EmitSymbolAttribute(Name, MCSA_Global);
else if (Alias.hasWeakLinkage() || Alias.hasLinkOnceLinkage())
OutStreamer.EmitSymbolAttribute(Name, MCSA_WeakReference);
else
assert(Alias.hasLocalLinkage() && "Invalid alias linkage");
EmitVisibility(Name, Alias.getVisibility());
// Emit the directives as assignments aka .set:
OutStreamer.EmitAssignment(Name, lowerConstant(Alias.getAliasee()));
}
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(M, *MI, *this);
// Emit llvm.ident metadata in an '.ident' directive.
EmitModuleIdents(M);
// Emit __morestack address if needed for indirect calls.
if (MMI->usesMorestackAddr()) {
const MCSection *ReadOnlySection =
getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly(),
/*C=*/nullptr);
OutStreamer.SwitchSection(ReadOnlySection);
MCSymbol *AddrSymbol =
OutContext.GetOrCreateSymbol(StringRef("__morestack_addr"));
OutStreamer.EmitLabel(AddrSymbol);
unsigned PtrSize = TM.getDataLayout()->getPointerSize(0);
OutStreamer.EmitSymbolValue(GetExternalSymbolSymbol("__morestack"),
PtrSize);
}
// 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 = nullptr;
MMI = nullptr;
OutStreamer.Finish();
OutStreamer.reset();
return false;
}
void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
this->MF = &MF;
// Get the function symbol.
CurrentFnSym = getSymbol(MF.getFunction());
CurrentFnSymForSize = CurrentFnSym;
CurrentFnBegin = nullptr;
bool NeedsLocalForSize = MAI->needsLocalForSize();
if (!MMI->getLandingPads().empty() || MMI->hasDebugInfo() ||
NeedsLocalForSize) {
CurrentFnBegin = createTempSymbol("func_begin", getFunctionNumber());
if (NeedsLocalForSize)
CurrentFnSymForSize = CurrentFnBegin;
}
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 =
CPE.getSectionKind(TM.getDataLayout());
const Constant *C = nullptr;
if (!CPE.isMachineConstantPoolEntry())
C = CPE.Val.ConstVal;
const MCSection *S = getObjFileLowering().getSectionForConstant(Kind, C);
// 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.
const MCSection *CurSection = nullptr;
unsigned Offset = 0;
for (unsigned i = 0, e = CPSections.size(); i != e; ++i) {
for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) {
unsigned CPI = CPSections[i].CPEs[j];
MCSymbol *Sym = GetCPISymbol(CPI);
if (!Sym->isUndefined())
continue;
if (CurSection != CPSections[i].S) {
OutStreamer.SwitchSection(CPSections[i].S);
EmitAlignment(Log2_32(CPSections[i].Alignment));
CurSection = CPSections[i].S;
Offset = 0;
}
MachineConstantPoolEntry CPE = CP[CPI];
// Emit inter-object padding for alignment.
unsigned AlignMask = CPE.getAlignment() - 1;
unsigned NewOffset = (Offset + AlignMask) & ~AlignMask;
OutStreamer.EmitZeros(NewOffset - Offset);
Type *Ty = CPE.getType();
Offset = NewOffset +
TM.getDataLayout()->getTypeAllocSize(Ty);
OutStreamer.EmitLabel(Sym);
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 DataLayout *DL = MF->getTarget().getDataLayout();
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
if (!MJTI) 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();
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
*F);
if (JTInDiffSection) {
// Drop it in the readonly section.
const MCSection *ReadOnlySection =
TLOF.getSectionForJumpTable(*F, *Mang, TM);
OutStreamer.SwitchSection(ReadOnlySection);
}
EmitAlignment(Log2_32(
MJTI->getEntryAlignment(*TM.getDataLayout())));
// Jump tables in code sections are marked with a data_region directive
// where that's supported.
if (!JTInDiffSection)
OutStreamer.EmitDataRegion(MCDR_DataRegionJT32);
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 using .set avoids a relocation,
/// emit a .set directive for each unique entry.
if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
MAI->doesSetDirectiveSuppressesReloc()) {
SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
const TargetLowering *TLI = MF->getSubtarget().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).second)
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 && DL->hasLinkerPrivateGlobalPrefix())
// 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);
}
if (!JTInDiffSection)
OutStreamer.EmitDataRegion(MCDR_DataRegionEnd);
}
/// 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 = nullptr;
switch (MJTI->getEntryKind()) {
case MachineJumpTableInfo::EK_Inline:
llvm_unreachable("Cannot emit EK_Inline jump table entry");
case MachineJumpTableInfo::EK_Custom32:
Value = MF->getSubtarget().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_GPRel64BlockAddress: {
// EK_GPRel64BlockAddress - Each entry is an address of block, encoded
// with a relocation as gp-relative, e.g.:
// .gpdword LBB123
MCSymbol *MBBSym = MBB->getSymbol();
OutStreamer.EmitGPRel64Value(MCSymbolRefExpr::Create(MBBSym, OutContext));
return;
}
case MachineJumpTableInfo::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 avoids relocations, this is emitted as:
// .set L4_5_set_123, LBB123 - LJTI1_2
// .word L4_5_set_123
if (MAI->doesSetDirectiveSuppressesReloc()) {
Value = MCSymbolRefExpr::Create(GetJTSetSymbol(UID, MBB->getNumber()),
OutContext);
break;
}
Value = MCSymbolRefExpr::Create(MBB->getSymbol(), OutContext);
const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF, UID, OutContext);
Value = MCBinaryExpr::CreateSub(Value, Base, OutContext);
break;
}
}
assert(Value && "Unknown entry kind!");
unsigned EntrySize =
MJTI->getEntrySize(*TM.getDataLayout());
OutStreamer.EmitValue(Value, EntrySize);
}
/// 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(cast<ConstantArray>(GV->getInitializer()));
return true;
}
// Ignore debug and non-emitted data. This handles llvm.compiler.used.
if (StringRef(GV->getSection()) == "llvm.metadata" ||
GV->hasAvailableExternallyLinkage())
return true;
if (!GV->hasAppendingLinkage()) return false;
assert(GV->hasInitializer() && "Not a special LLVM global!");
if (GV->getName() == "llvm.global_ctors") {
EmitXXStructorList(GV->getInitializer(), /* isCtor */ true);
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") {
EmitXXStructorList(GV->getInitializer(), /* isCtor */ false);
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(const ConstantArray *InitList) {
// Should be an array of 'i8*'.
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
const GlobalValue *GV =
dyn_cast<GlobalValue>(InitList->getOperand(i)->stripPointerCasts());
if (GV)
OutStreamer.EmitSymbolAttribute(getSymbol(GV), MCSA_NoDeadStrip);
}
}
namespace {
struct Structor {
Structor() : Priority(0), Func(nullptr), ComdatKey(nullptr) {}
int Priority;
llvm::Constant *Func;
llvm::GlobalValue *ComdatKey;
};
} // end namespace
/// EmitXXStructorList - Emit the ctor or dtor list taking into account the init
/// priority.
void AsmPrinter::EmitXXStructorList(const Constant *List, bool isCtor) {
// Should be an array of '{ int, void ()* }' structs. The first value is the
// init priority.
if (!isa<ConstantArray>(List)) return;
// Sanity check the structors list.
const ConstantArray *InitList = dyn_cast<ConstantArray>(List);
if (!InitList) return; // Not an array!
StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
// FIXME: Only allow the 3-field form in LLVM 4.0.
if (!ETy || ETy->getNumElements() < 2 || ETy->getNumElements() > 3)
return; // Not an array of two or three elements!
if (!isa<IntegerType>(ETy->getTypeAtIndex(0U)) ||
!isa<PointerType>(ETy->getTypeAtIndex(1U))) return; // Not (int, ptr).
if (ETy->getNumElements() == 3 && !isa<PointerType>(ETy->getTypeAtIndex(2U)))
return; // Not (int, ptr, ptr).
// Gather the structors in a form that's convenient for sorting by priority.
SmallVector<Structor, 8> Structors;
for (Value *O : InitList->operands()) {
ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
if (!CS) continue; // Malformed.
if (CS->getOperand(1)->isNullValue())
break; // Found a null terminator, skip the rest.
ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
if (!Priority) continue; // Malformed.
Structors.push_back(Structor());
Structor &S = Structors.back();
S.Priority = Priority->getLimitedValue(65535);
S.Func = CS->getOperand(1);
if (ETy->getNumElements() == 3 && !CS->getOperand(2)->isNullValue())
S.ComdatKey = dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts());
}
// Emit the function pointers in the target-specific order
const DataLayout *DL = TM.getDataLayout();
unsigned Align = Log2_32(DL->getPointerPrefAlignment());
std::stable_sort(Structors.begin(), Structors.end(),
[](const Structor &L,
const Structor &R) { return L.Priority < R.Priority; });
for (Structor &S : Structors) {
const TargetLoweringObjectFile &Obj = getObjFileLowering();
const MCSymbol *KeySym = nullptr;
if (GlobalValue *GV = S.ComdatKey) {
if (GV->hasAvailableExternallyLinkage())
// If the associated variable is available_externally, some other TU
// will provide its dynamic initializer.
continue;
KeySym = getSymbol(GV);
}
const MCSection *OutputSection =
(isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym)
: Obj.getStaticDtorSection(S.Priority, KeySym));
OutStreamer.SwitchSection(OutputSection);
if (OutStreamer.getCurrentSection() != OutStreamer.getPreviousSection())
EmitAlignment(Align);
EmitXXStructor(S.Func);
}
}
void AsmPrinter::EmitModuleIdents(Module &M) {
if (!MAI->hasIdentDirective())
return;
if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) {
for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
const MDNode *N = NMD->getOperand(i);
assert(N->getNumOperands() == 1 &&
"llvm.ident metadata entry can have only one operand");
const MDString *S = cast<MDString>(N->getOperand(0));
OutStreamer.EmitIdent(S->getString());
}
}
}
//===--------------------------------------------------------------------===//
// Emission and print routines
//
/// EmitInt8 - Emit a byte directive and value.
///
void AsmPrinter::EmitInt8(int Value) const {
OutStreamer.EmitIntValue(Value, 1);
}
/// EmitInt16 - Emit a short directive and value.
///
void AsmPrinter::EmitInt16(int Value) const {
OutStreamer.EmitIntValue(Value, 2);
}
/// EmitInt32 - Emit a long directive and value.
///
void AsmPrinter::EmitInt32(int Value) const {
OutStreamer.EmitIntValue(Value, 4);
}
/// 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 avoids relocations.
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->doesSetDirectiveSuppressesReloc()) {
OutStreamer.EmitValue(Diff, Size);
return;
}
// Otherwise, emit with .set (aka assignment).
MCSymbol *SetLabel = GetTempSymbol("set", SetCounter++);
OutStreamer.EmitAssignment(SetLabel, Diff);
OutStreamer.EmitSymbolValue(SetLabel, Size);
}
/// 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,
bool IsSectionRelative) const {
if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) {
OutStreamer.EmitCOFFSecRel32(Label);
return;
}
// Emit Label+Offset (or just Label if Offset is zero)
const MCExpr *Expr = MCSymbolRefExpr::Create(Label, OutContext);
if (Offset)
Expr = MCBinaryExpr::CreateAdd(
Expr, MCConstantExpr::Create(Offset, OutContext), OutContext);
OutStreamer.EmitValue(Expr, Size);
}
//===----------------------------------------------------------------------===//
// 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 GlobalObject *GV) const {
if (GV)
NumBits = getGVAlignmentLog2(GV, *TM.getDataLayout(),
NumBits);
if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
assert(NumBits <
static_cast<unsigned>(std::numeric_limits<unsigned>::digits) &&
"undefined behavior");
if (getCurrentSection()->getKind().isText())
OutStreamer.EmitCodeAlignment(1u << NumBits);
else
OutStreamer.EmitValueToAlignment(1u << NumBits);
}
//===----------------------------------------------------------------------===//
// Constant emission.
//===----------------------------------------------------------------------===//
const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
MCContext &Ctx = 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(getSymbol(GV), Ctx);
if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV))
return MCSymbolRefExpr::Create(GetBlockAddressSymbol(BA), Ctx);
const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV);
if (!CE) {
llvm_unreachable("Unknown constant value to lower!");
}
if (const MCExpr *RelocExpr
= getObjFileLowering().getExecutableRelativeSymbol(CE, *Mang, TM))
return RelocExpr;
switch (CE->getOpcode()) {
default:
// If the code isn't optimized, there may be outstanding folding
// opportunities. Attempt to fold the expression using DataLayout as a
// last resort before giving up.
if (Constant *C = ConstantFoldConstantExpression(
CE, TM.getDataLayout()))
if (C != CE)
return lowerConstant(C);
// Otherwise report the problem to the user.
{
std::string S;
raw_string_ostream OS(S);
OS << "Unsupported expression in static initializer: ";
CE->printAsOperand(OS, /*PrintType=*/false,
!MF ? nullptr : MF->getFunction()->getParent());
report_fatal_error(OS.str());
}
case Instruction::GetElementPtr: {
const DataLayout &DL = *TM.getDataLayout();
// Generate a symbolic expression for the byte address
APInt OffsetAI(DL.getPointerTypeSizeInBits(CE->getType()), 0);
cast<GEPOperator>(CE)->accumulateConstantOffset(DL, OffsetAI);
const MCExpr *Base = lowerConstant(CE->getOperand(0));
if (!OffsetAI)
return Base;
int64_t Offset = OffsetAI.getSExtValue();
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));
case Instruction::IntToPtr: {
const DataLayout &DL = *TM.getDataLayout();
// 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, DL.getIntPtrType(CV->getType()),
false/*ZExt*/);
return lowerConstant(Op);
}
case Instruction::PtrToInt: {
const DataLayout &DL = *TM.getDataLayout();
// 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);
Type *Ty = CE->getType();
const MCExpr *OpExpr = lowerConstant(Op);
// We can emit the pointer value into this slot if the slot is an
// integer slot equal to the size of the pointer.
if (DL.getTypeAllocSize(Ty) == DL.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 = DL.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));
const MCExpr *RHS = lowerConstant(CE->getOperand(1));
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, AsmPrinter &AP,
const Constant *BaseCV = nullptr,
uint64_t Offset = 0);
/// isRepeatedByteSequence - Determine whether the given value is
/// composed of a repeated sequence of identical bytes and return the
/// byte value. If it is not a repeated sequence, return -1.
static int isRepeatedByteSequence(const ConstantDataSequential *V) {
StringRef Data = V->getRawDataValues();
assert(!Data.empty() && "Empty aggregates should be CAZ node");
char C = Data[0];
for (unsigned i = 1, e = Data.size(); i != e; ++i)
if (Data[i] != C) return -1;
return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1.
}
/// isRepeatedByteSequence - Determine whether the given value is
/// composed of a repeated sequence of identical bytes and return the
/// byte value. If it is not a repeated sequence, return -1.
static int isRepeatedByteSequence(const Value *V, TargetMachine &TM) {
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
if (CI->getBitWidth() > 64) return -1;
uint64_t Size =
TM.getDataLayout()->getTypeAllocSize(V->getType());
uint64_t Value = CI->getZExtValue();
// Make sure the constant is at least 8 bits long and has a power
// of 2 bit width. This guarantees the constant bit width is
// always a multiple of 8 bits, avoiding issues with padding out
// to Size and other such corner cases.
if (CI->getBitWidth() < 8 || !isPowerOf2_64(CI->getBitWidth())) return -1;
uint8_t Byte = static_cast<uint8_t>(Value);
for (unsigned i = 1; i < Size; ++i) {
Value >>= 8;
if (static_cast<uint8_t>(Value) != Byte) return -1;
}
return Byte;
}
if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) {
// Make sure all array elements are sequences of the same repeated
// byte.
assert(CA->getNumOperands() != 0 && "Should be a CAZ");
int Byte = isRepeatedByteSequence(CA->getOperand(0), TM);
if (Byte == -1) return -1;
for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) {
int ThisByte = isRepeatedByteSequence(CA->getOperand(i), TM);
if (ThisByte == -1) return -1;
if (Byte != ThisByte) return -1;
}
return Byte;
}
if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V))
return isRepeatedByteSequence(CDS);
return -1;
}
static void emitGlobalConstantDataSequential(const ConstantDataSequential *CDS,
AsmPrinter &AP){
// See if we can aggregate this into a .fill, if so, emit it as such.
int Value = isRepeatedByteSequence(CDS, AP.TM);
if (Value != -1) {
uint64_t Bytes =
AP.TM.getDataLayout()->getTypeAllocSize(
CDS->getType());
// Don't emit a 1-byte object as a .fill.
if (Bytes > 1)
return AP.OutStreamer.EmitFill(Bytes, Value);
}
// If this can be emitted with .ascii/.asciz, emit it as such.
if (CDS->isString())
return AP.OutStreamer.EmitBytes(CDS->getAsString());
// Otherwise, emit the values in successive locations.
unsigned ElementByteSize = CDS->getElementByteSize();
if (isa<IntegerType>(CDS->getElementType())) {
for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
if (AP.isVerbose())
AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n",
CDS->getElementAsInteger(i));
AP.OutStreamer.EmitIntValue(CDS->getElementAsInteger(i),
ElementByteSize);
}
} else if (ElementByteSize == 4) {
// FP Constants are printed as integer constants to avoid losing
// precision.
assert(CDS->getElementType()->isFloatTy());
for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
union {
float F;
uint32_t I;
};
F = CDS->getElementAsFloat(i);
if (AP.isVerbose())
AP.OutStreamer.GetCommentOS() << "float " << F << '\n';
AP.OutStreamer.EmitIntValue(I, 4);
}
} else {
assert(CDS->getElementType()->isDoubleTy());
for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
union {
double F;
uint64_t I;
};
F = CDS->getElementAsDouble(i);
if (AP.isVerbose())
AP.OutStreamer.GetCommentOS() << "double " << F << '\n';
AP.OutStreamer.EmitIntValue(I, 8);
}
}
const DataLayout &DL = *AP.TM.getDataLayout();
unsigned Size = DL.getTypeAllocSize(CDS->getType());
unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) *
CDS->getNumElements();
if (unsigned Padding = Size - EmittedSize)
AP.OutStreamer.EmitZeros(Padding);
}
static void emitGlobalConstantArray(const ConstantArray *CA, AsmPrinter &AP,
const Constant *BaseCV, uint64_t Offset) {
// See if we can aggregate some values. Make sure it can be
// represented as a series of bytes of the constant value.
int Value = isRepeatedByteSequence(CA, AP.TM);
const DataLayout &DL = *AP.TM.getDataLayout();
if (Value != -1) {
uint64_t Bytes = DL.getTypeAllocSize(CA->getType());
AP.OutStreamer.EmitFill(Bytes, Value);
}
else {
for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) {
emitGlobalConstantImpl(CA->getOperand(i), AP, BaseCV, Offset);
Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType());
}
}
}
static void emitGlobalConstantVector(const ConstantVector *CV, AsmPrinter &AP) {
for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i)
emitGlobalConstantImpl(CV->getOperand(i), AP);
const DataLayout &DL = *AP.TM.getDataLayout();
unsigned Size = DL.getTypeAllocSize(CV->getType());
unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) *
CV->getType()->getNumElements();
if (unsigned Padding = Size - EmittedSize)
AP.OutStreamer.EmitZeros(Padding);
}
static void emitGlobalConstantStruct(const ConstantStruct *CS, AsmPrinter &AP,
const Constant *BaseCV, uint64_t Offset) {
// Print the fields in successive locations. Pad to align if needed!
const DataLayout *DL = AP.TM.getDataLayout();
unsigned Size = DL->getTypeAllocSize(CS->getType());
const StructLayout *Layout = DL->getStructLayout(CS->getType());
uint64_t SizeSoFar = 0;
for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) {
const Constant *Field = CS->getOperand(i);
// Print the actual field value.
emitGlobalConstantImpl(Field, AP, BaseCV, Offset+SizeSoFar);
// Check if padding is needed and insert one or more 0s.
uint64_t FieldSize = DL->getTypeAllocSize(Field->getType());
uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1))
- Layout->getElementOffset(i)) - FieldSize;
SizeSoFar += FieldSize + PadSize;
// 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);
}
assert(SizeSoFar == Layout->getSizeInBytes() &&
"Layout of constant struct may be incorrect!");
}
static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) {
APInt API = CFP->getValueAPF().bitcastToAPInt();
// First print a comment with what we think the original floating-point value
// should have been.
if (AP.isVerbose()) {
SmallString<8> StrVal;
CFP->getValueAPF().toString(StrVal);
if (CFP->getType())
CFP->getType()->print(AP.OutStreamer.GetCommentOS());
else
AP.OutStreamer.GetCommentOS() << "Printing <null> Type";
AP.OutStreamer.GetCommentOS() << ' ' << StrVal << '\n';
}
// Now iterate through the APInt chunks, emitting them in endian-correct
// order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit
// floats).
unsigned NumBytes = API.getBitWidth() / 8;
unsigned TrailingBytes = NumBytes % sizeof(uint64_t);
const uint64_t *p = API.getRawData();
// PPC's long double has odd notions of endianness compared to how LLVM
// handles it: p[0] goes first for *big* endian on PPC.
if (AP.TM.getDataLayout()->isBigEndian() &&
!CFP->getType()->isPPC_FP128Ty()) {
int Chunk = API.getNumWords() - 1;
if (TrailingBytes)
AP.OutStreamer.EmitIntValue(p[Chunk--], TrailingBytes);
for (; Chunk >= 0; --Chunk)
AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t));
} else {
unsigned Chunk;
for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk)
AP.OutStreamer.EmitIntValue(p[Chunk], sizeof(uint64_t));
if (TrailingBytes)
AP.OutStreamer.EmitIntValue(p[Chunk], TrailingBytes);
}
// Emit the tail padding for the long double.
const DataLayout &DL = *AP.TM.getDataLayout();
AP.OutStreamer.EmitZeros(DL.getTypeAllocSize(CFP->getType()) -
DL.getTypeStoreSize(CFP->getType()));
}
static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) {
const DataLayout *DL = AP.TM.getDataLayout();
unsigned BitWidth = CI->getBitWidth();
// Copy the value as we may massage the layout for constants whose bit width
// is not a multiple of 64-bits.
APInt Realigned(CI->getValue());
uint64_t ExtraBits = 0;
unsigned ExtraBitsSize = BitWidth & 63;
if (ExtraBitsSize) {
// The bit width of the data is not a multiple of 64-bits.
// The extra bits are expected to be at the end of the chunk of the memory.
// Little endian:
// * Nothing to be done, just record the extra bits to emit.
// Big endian:
// * Record the extra bits to emit.
// * Realign the raw data to emit the chunks of 64-bits.
if (DL->isBigEndian()) {
// Basically the structure of the raw data is a chunk of 64-bits cells:
// 0 1 BitWidth / 64
// [chunk1][chunk2] ... [chunkN].
// The most significant chunk is chunkN and it should be emitted first.
// However, due to the alignment issue chunkN contains useless bits.
// Realign the chunks so that they contain only useless information:
// ExtraBits 0 1 (BitWidth / 64) - 1
// chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN]
ExtraBits = Realigned.getRawData()[0] &
(((uint64_t)-1) >> (64 - ExtraBitsSize));
Realigned = Realigned.lshr(ExtraBitsSize);
} else
ExtraBits = Realigned.getRawData()[BitWidth / 64];
}
// 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 = Realigned.getRawData();
for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) {
uint64_t Val = DL->isBigEndian() ? RawData[e - i - 1] : RawData[i];
AP.OutStreamer.EmitIntValue(Val, 8);
}
if (ExtraBitsSize) {
// Emit the extra bits after the 64-bits chunks.
// Emit a directive that fills the expected size.
uint64_t Size = AP.TM.getDataLayout()->getTypeAllocSize(
CI->getType());
Size -= (BitWidth / 64) * 8;
assert(Size && Size * 8 >= ExtraBitsSize &&
(ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize)))
== ExtraBits && "Directive too small for extra bits.");
AP.OutStreamer.EmitIntValue(ExtraBits, Size);
}
}
/// \brief Transform a not absolute MCExpr containing a reference to a GOT
/// equivalent global, by a target specific GOT pc relative access to the
/// final symbol.
static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME,
const Constant *BaseCst,
uint64_t Offset) {
// The global @foo below illustrates a global that uses a got equivalent.
//
// @bar = global i32 42
// @gotequiv = private unnamed_addr constant i32* @bar
// @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64),
// i64 ptrtoint (i32* @foo to i64))
// to i32)
//
// The cstexpr in @foo is converted into the MCExpr `ME`, where we actually
// check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the
// form:
//
// foo = cstexpr, where
// cstexpr := <gotequiv> - "." + <cst>
// cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst>
//
// After canonicalization by EvaluateAsRelocatable `ME` turns into:
//
// cstexpr := <gotequiv> - <foo> + gotpcrelcst, where
// gotpcrelcst := <offset from @foo base> + <cst>
//
MCValue MV;
if (!(*ME)->EvaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute())
return;
const MCSymbol *GOTEquivSym = &MV.getSymA()->getSymbol();
if (!AP.GlobalGOTEquivs.count(GOTEquivSym))
return;
const GlobalValue *BaseGV = dyn_cast<GlobalValue>(BaseCst);
if (!BaseGV)
return;
const MCSymbol *BaseSym = AP.getSymbol(BaseGV);
if (BaseSym != &MV.getSymB()->getSymbol())
return;
// Make sure to match:
//
// gotpcrelcst := <offset from @foo base> + <cst>
//
// If gotpcrelcst is positive it means that we can safely fold the pc rel
// displacement into the GOTPCREL. We can also can have an extra offset <cst>
// if the target knows how to encode it.
//
int64_t GOTPCRelCst = Offset + MV.getConstant();
if (GOTPCRelCst < 0)
return;
if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0)
return;
// Emit the GOT PC relative to replace the got equivalent global, i.e.:
//
// bar:
// .long 42
// gotequiv:
// .quad bar
// foo:
// .long gotequiv - "." + <cst>
//
// is replaced by the target specific equivalent to:
//
// bar:
// .long 42
// foo:
// .long bar@GOTPCREL+<gotpcrelcst>
//
AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym];
const GlobalVariable *GV = Result.first;
unsigned NumUses = Result.second;
const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0));
const MCSymbol *FinalSym = AP.getSymbol(FinalGV);
*ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel(
FinalSym, MV, Offset, AP.MMI, AP.OutStreamer);
// Update GOT equivalent usage information
--NumUses;
if (NumUses)
AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses);
else
AP.GlobalGOTEquivs.erase(GOTEquivSym);
}
static void emitGlobalConstantImpl(const Constant *CV, AsmPrinter &AP,
const Constant *BaseCV, uint64_t Offset) {
const DataLayout *DL = AP.TM.getDataLayout();
uint64_t Size = DL->getTypeAllocSize(CV->getType());
// Globals with sub-elements such as combinations of arrays and structs
// are handled recursively by emitGlobalConstantImpl. Keep track of the
// constant symbol base and the current position with BaseCV and Offset.
if (!BaseCV && CV->hasOneUse())
BaseCV = dyn_cast<Constant>(CV->user_back());
if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV))
return AP.OutStreamer.EmitZeros(Size);
if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
switch (Size) {
case 1:
case 2:
case 4:
case 8:
if (AP.isVerbose())
AP.OutStreamer.GetCommentOS() << format("0x%" PRIx64 "\n",
CI->getZExtValue());
AP.OutStreamer.EmitIntValue(CI->getZExtValue(), Size);
return;
default:
emitGlobalConstantLargeInt(CI, AP);
return;
}
}
if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV))
return emitGlobalConstantFP(CFP, AP);
if (isa<ConstantPointerNull>(CV)) {
AP.OutStreamer.EmitIntValue(0, Size);
return;
}
if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV))
return emitGlobalConstantDataSequential(CDS, AP);
if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV))
return emitGlobalConstantArray(CVA, AP, BaseCV, Offset);
if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV))
return emitGlobalConstantStruct(CVS, AP, BaseCV, Offset);
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
// Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of
// vectors).
if (CE->getOpcode() == Instruction::BitCast)
return emitGlobalConstantImpl(CE->getOperand(0), AP);
if (Size > 8) {
// If the constant expression's size is greater than 64-bits, then we have
// to emit the value in chunks. Try to constant fold the value and emit it
// that way.
Constant *New = ConstantFoldConstantExpression(CE, DL);
if (New && New != CE)
return emitGlobalConstantImpl(New, AP);
}
}
if (const ConstantVector *V = dyn_cast<ConstantVector>(CV))
return emitGlobalConstantVector(V, AP);
// Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it
// thread the streamer with EmitValue.
const MCExpr *ME = AP.lowerConstant(CV);
// Since lowerConstant already folded and got rid of all IR pointer and
// integer casts, detect GOT equivalent accesses by looking into the MCExpr
// directly.
if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel())
handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset);
AP.OutStreamer.EmitValue(ME, Size);
}
/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
void AsmPrinter::EmitGlobalConstant(const Constant *CV) {
uint64_t Size =
TM.getDataLayout()->getTypeAllocSize(CV->getType());
if (Size)
emitGlobalConstantImpl(CV, *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);
}
}
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(const Twine &Name, unsigned ID) const {
const DataLayout *DL = TM.getDataLayout();
return OutContext.GetOrCreateSymbol(Twine(DL->getPrivateGlobalPrefix()) +
Name + Twine(ID));
}
/// GetTempSymbol - Return an assembler temporary label with the specified
/// stem.
MCSymbol *AsmPrinter::GetTempSymbol(const Twine &Name) const {
const DataLayout *DL = TM.getDataLayout();
return OutContext.GetOrCreateSymbol(Twine(DL->getPrivateGlobalPrefix())+
Name);
}
MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name, unsigned ID) const {
return OutContext.createTempSymbol(Name + Twine(ID));
}
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 {
const DataLayout *DL = TM.getDataLayout();
return OutContext.GetOrCreateSymbol
(Twine(DL->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 {
const DataLayout *DL = TM.getDataLayout();
return OutContext.GetOrCreateSymbol
(Twine(DL->getPrivateGlobalPrefix()) + Twine(getFunctionNumber()) + "_" +
Twine(UID) + "_set_" + Twine(MBBID));
}
MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
StringRef Suffix) const {
return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, *Mang,
TM);
}
/// 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) 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 (const MachineLoop *CL : *Loop) {
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) 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(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*> Symbols = MMI->getAddrLabelSymbolToEmit(BB);
for (auto *Sym : Symbols)
OutStreamer.EmitLabel(Sym);
}
// Print some verbose block comments.
if (isVerbose()) {
if (const BasicBlock *BB = MBB.getBasicBlock())
if (BB->hasName())
OutStreamer.AddComment("%" + BB->getName());
emitBasicBlockLoopComments(MBB, LI, *this);
}
// Print the main label for the block.
if (MBB.pred_empty() || isBlockOnlyReachableByFallthrough(&MBB)) {
if (isVerbose()) {
// NOTE: Want this comment at start of line, don't emit with AddComment.
OutStreamer.emitRawComment(" BB#" + Twine(MBB.getNumber()) + ":", false);
}
} else {
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.
if (MBB->pred_size() > 1)
return false;
// The predecessor has to be immediately before this block.
MachineBasicBlock *Pred = *MBB->pred_begin();
if (!Pred->isLayoutSuccessor(MBB))
return false;
// If the block is completely empty, then it definitely does fall through.
if (Pred->empty())
return true;
// Check the terminators in the previous blocks
for (const auto &MI : Pred->terminators()) {
// If it is not a simple branch, we are in a table somewhere.
if (!MI.isBranch() || MI.isIndirectBranch())
return false;
// If we are the operands of one of the branches, this is not a fall
// through. Note that targets with delay slots will usually bundle
// terminators with the delay slot instruction.
for (ConstMIBundleOperands OP(&MI); OP.isValid(); ++OP) {
if (OP->isJTI())
return false;
if (OP->isMBB() && OP->getMBB() == MBB)
return false;
}
}
return true;
}
GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) {
if (!S.usesMetadata())
return nullptr;
assert(!S.useStatepoints() && "statepoints do not currently support custom"
" stackmap formats, please see the documentation for a description of"
" the default format. If you really need a custom serialized format,"
" please file a bug");
gcp_map_type &GCMap = getGCMap(GCMetadataPrinters);
gcp_map_type::iterator GCPI = GCMap.find(&S);
if (GCPI != GCMap.end())
return GCPI->second.get();
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) {
std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate();
GMP->S = &S;
auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP)));
return IterBool.first->second.get();
}
report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name));
}
/// Pin vtable to this file.
AsmPrinterHandler::~AsmPrinterHandler() {}
void AsmPrinterHandler::markFunctionEnd() {}
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