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//===- AsmPrinter.cpp - Common AsmPrinter code ----------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the AsmPrinter class.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/AsmPrinter.h"
#include "CodeViewDebug.h"
#include "DwarfDebug.h"
#include "DwarfException.h"
#include "PseudoProbePrinter.h"
#include "WasmException.h"
#include "WinCFGuard.h"
#include "WinException.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/TinyPtrVector.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Analysis/MemoryLocation.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/CodeGen/GCMetadata.h"
#include "llvm/CodeGen/GCMetadataPrinter.h"
#include "llvm/CodeGen/LazyMachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBundle.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
#include "llvm/CodeGen/StackMaps.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetOpcodes.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/Config/config.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Comdat.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/EHPersonalities.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GCStrategy.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalIFunc.h"
#include "llvm/IR/GlobalObject.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PseudoProbe.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/SectionKind.h"
#include "llvm/Object/ELFTypes.h"
#include "llvm/Pass.h"
#include "llvm/Remarks/RemarkStreamer.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Timer.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/TargetParser/Triple.h"
#include <algorithm>
#include <cassert>
#include <cinttypes>
#include <cstdint>
#include <iterator>
#include <memory>
#include <optional>
#include <string>
#include <utility>
#include <vector>
using namespace llvm;
#define DEBUG_TYPE "asm-printer"
static cl::opt<std::string> BasicBlockProfileDump(
"mbb-profile-dump", cl::Hidden,
cl::desc("Basic block profile dump for external cost modelling. If "
"matching up BBs with afterwards, the compilation must be "
"performed with -basic-block-sections=labels. Enabling this "
"flag during in-process ThinLTO is not supported."));
const char DWARFGroupName[] = "dwarf";
const char DWARFGroupDescription[] = "DWARF Emission";
const char DbgTimerName[] = "emit";
const char DbgTimerDescription[] = "Debug Info Emission";
const char EHTimerName[] = "write_exception";
const char EHTimerDescription[] = "DWARF Exception Writer";
const char CFGuardName[] = "Control Flow Guard";
const char CFGuardDescription[] = "Control Flow Guard";
const char CodeViewLineTablesGroupName[] = "linetables";
const char CodeViewLineTablesGroupDescription[] = "CodeView Line Tables";
const char PPTimerName[] = "emit";
const char PPTimerDescription[] = "Pseudo Probe Emission";
const char PPGroupName[] = "pseudo probe";
const char PPGroupDescription[] = "Pseudo Probe Emission";
STATISTIC(EmittedInsts, "Number of machine instrs printed");
char AsmPrinter::ID = 0;
namespace {
class AddrLabelMapCallbackPtr final : CallbackVH {
AddrLabelMap *Map = nullptr;
public:
AddrLabelMapCallbackPtr() = default;
AddrLabelMapCallbackPtr(Value *V) : CallbackVH(V) {}
void setPtr(BasicBlock *BB) {
ValueHandleBase::operator=(BB);
}
void setMap(AddrLabelMap *map) { Map = map; }
void deleted() override;
void allUsesReplacedWith(Value *V2) override;
};
} // namespace
class llvm::AddrLabelMap {
MCContext &Context;
struct AddrLabelSymEntry {
/// The symbols for the label.
TinyPtrVector<MCSymbol *> Symbols;
Function *Fn; // The containing function of the BasicBlock.
unsigned Index; // The index in BBCallbacks for the BasicBlock.
};
DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
/// Callbacks for the BasicBlock's that we have entries for. We use this so
/// we get notified if a block is deleted or RAUWd.
std::vector<AddrLabelMapCallbackPtr> BBCallbacks;
/// This is a per-function list of symbols whose corresponding BasicBlock got
/// deleted. These symbols need to be emitted at some point in the file, so
/// AsmPrinter emits them after the function body.
DenseMap<AssertingVH<Function>, std::vector<MCSymbol *>>
DeletedAddrLabelsNeedingEmission;
public:
AddrLabelMap(MCContext &context) : Context(context) {}
~AddrLabelMap() {
assert(DeletedAddrLabelsNeedingEmission.empty() &&
"Some labels for deleted blocks never got emitted");
}
ArrayRef<MCSymbol *> getAddrLabelSymbolToEmit(BasicBlock *BB);
void takeDeletedSymbolsForFunction(Function *F,
std::vector<MCSymbol *> &Result);
void UpdateForDeletedBlock(BasicBlock *BB);
void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
};
ArrayRef<MCSymbol *> AddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) {
assert(BB->hasAddressTaken() &&
"Shouldn't get label for block without address taken");
AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
// If we already had an entry for this block, just return it.
if (!Entry.Symbols.empty()) {
assert(BB->getParent() == Entry.Fn && "Parent changed");
return Entry.Symbols;
}
// Otherwise, this is a new entry, create a new symbol for it and add an
// entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
BBCallbacks.emplace_back(BB);
BBCallbacks.back().setMap(this);
Entry.Index = BBCallbacks.size() - 1;
Entry.Fn = BB->getParent();
MCSymbol *Sym = BB->hasAddressTaken() ? Context.createNamedTempSymbol()
: Context.createTempSymbol();
Entry.Symbols.push_back(Sym);
return Entry.Symbols;
}
/// If we have any deleted symbols for F, return them.
void AddrLabelMap::takeDeletedSymbolsForFunction(
Function *F, std::vector<MCSymbol *> &Result) {
DenseMap<AssertingVH<Function>, std::vector<MCSymbol *>>::iterator I =
DeletedAddrLabelsNeedingEmission.find(F);
// If there are no entries for the function, just return.
if (I == DeletedAddrLabelsNeedingEmission.end())
return;
// Otherwise, take the list.
std::swap(Result, I->second);
DeletedAddrLabelsNeedingEmission.erase(I);
}
//===- Address of Block Management ----------------------------------------===//
ArrayRef<MCSymbol *>
AsmPrinter::getAddrLabelSymbolToEmit(const BasicBlock *BB) {
// Lazily create AddrLabelSymbols.
if (!AddrLabelSymbols)
AddrLabelSymbols = std::make_unique<AddrLabelMap>(OutContext);
return AddrLabelSymbols->getAddrLabelSymbolToEmit(
const_cast<BasicBlock *>(BB));
}
void AsmPrinter::takeDeletedSymbolsForFunction(
const Function *F, std::vector<MCSymbol *> &Result) {
// If no blocks have had their addresses taken, we're done.
if (!AddrLabelSymbols)
return;
return AddrLabelSymbols->takeDeletedSymbolsForFunction(
const_cast<Function *>(F), Result);
}
void AddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {
// If the block got deleted, there is no need for the symbol. If the symbol
// was already emitted, we can just forget about it, otherwise we need to
// queue it up for later emission when the function is output.
AddrLabelSymEntry Entry = std::move(AddrLabelSymbols[BB]);
AddrLabelSymbols.erase(BB);
assert(!Entry.Symbols.empty() && "Didn't have a symbol, why a callback?");
BBCallbacks[Entry.Index] = nullptr; // Clear the callback.
#if !LLVM_MEMORY_SANITIZER_BUILD
// BasicBlock is destroyed already, so this access is UB detectable by msan.
assert((BB->getParent() == nullptr || BB->getParent() == Entry.Fn) &&
"Block/parent mismatch");
#endif
for (MCSymbol *Sym : Entry.Symbols) {
if (Sym->isDefined())
return;
// If the block is not yet defined, we need to emit it at the end of the
// function. Add the symbol to the DeletedAddrLabelsNeedingEmission list
// for the containing Function. Since the block is being deleted, its
// parent may already be removed, we have to get the function from 'Entry'.
DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);
}
}
void AddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
// Get the entry for the RAUW'd block and remove it from our map.
AddrLabelSymEntry OldEntry = std::move(AddrLabelSymbols[Old]);
AddrLabelSymbols.erase(Old);
assert(!OldEntry.Symbols.empty() && "Didn't have a symbol, why a callback?");
AddrLabelSymEntry &NewEntry = AddrLabelSymbols[New];
// If New is not address taken, just move our symbol over to it.
if (NewEntry.Symbols.empty()) {
BBCallbacks[OldEntry.Index].setPtr(New); // Update the callback.
NewEntry = std::move(OldEntry); // Set New's entry.
return;
}
BBCallbacks[OldEntry.Index] = nullptr; // Update the callback.
// Otherwise, we need to add the old symbols to the new block's set.
llvm::append_range(NewEntry.Symbols, OldEntry.Symbols);
}
void AddrLabelMapCallbackPtr::deleted() {
Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
}
void AddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
}
/// getGVAlignment - Return the alignment to use for the specified global
/// value. This rounds up to the preferred alignment if possible and legal.
Align AsmPrinter::getGVAlignment(const GlobalObject *GV, const DataLayout &DL,
Align InAlign) {
Align Alignment;
if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
Alignment = DL.getPreferredAlign(GVar);
// If InAlign is specified, round it to it.
if (InAlign > Alignment)
Alignment = InAlign;
// If the GV has a specified alignment, take it into account.
const MaybeAlign GVAlign(GV->getAlign());
if (!GVAlign)
return Alignment;
assert(GVAlign && "GVAlign must be set");
// 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 > Alignment || GV->hasSection())
Alignment = *GVAlign;
return Alignment;
}
AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer)
: MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()),
OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)),
SM(*this) {
VerboseAsm = OutStreamer->isVerboseAsm();
DwarfUsesRelocationsAcrossSections =
MAI->doesDwarfUseRelocationsAcrossSections();
}
AsmPrinter::~AsmPrinter() {
assert(!DD && Handlers.size() == NumUserHandlers &&
"Debug/EH info didn't get finalized");
}
bool AsmPrinter::isPositionIndependent() const {
return TM.isPositionIndependent();
}
/// getFunctionNumber - Return a unique ID for the current function.
unsigned AsmPrinter::getFunctionNumber() const {
return MF->getFunctionNumber();
}
const TargetLoweringObjectFile &AsmPrinter::getObjFileLowering() const {
return *TM.getObjFileLowering();
}
const DataLayout &AsmPrinter::getDataLayout() const {
assert(MMI && "MMI could not be nullptr!");
return MMI->getModule()->getDataLayout();
}
// Do not use the cached DataLayout because some client use it without a Module
// (dsymutil, llvm-dwarfdump).
unsigned AsmPrinter::getPointerSize() const {
return TM.getPointerSize(0); // FIXME: Default address space
}
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());
}
void AsmPrinter::emitInitialRawDwarfLocDirective(const MachineFunction &MF) {
if (DD) {
assert(OutStreamer->hasRawTextSupport() &&
"Expected assembly output mode.");
// This is NVPTX specific and it's unclear why.
// PR51079: If we have code without debug information we need to give up.
DISubprogram *MFSP = MF.getFunction().getSubprogram();
if (!MFSP)
return;
(void)DD->emitInitialLocDirective(MF, /*CUID=*/0);
}
}
/// getCurrentSection() - Return the current section we are emitting to.
const MCSection *AsmPrinter::getCurrentSection() const {
return OutStreamer->getCurrentSectionOnly();
}
void AsmPrinter::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(AU);
AU.addRequired<MachineOptimizationRemarkEmitterPass>();
AU.addRequired<GCModuleInfo>();
AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
}
bool AsmPrinter::doInitialization(Module &M) {
auto *MMIWP = getAnalysisIfAvailable<MachineModuleInfoWrapperPass>();
MMI = MMIWP ? &MMIWP->getMMI() : nullptr;
HasSplitStack = false;
HasNoSplitStack = false;
AddrLabelSymbols = nullptr;
// Initialize TargetLoweringObjectFile.
const_cast<TargetLoweringObjectFile&>(getObjFileLowering())
.Initialize(OutContext, TM);
const_cast<TargetLoweringObjectFile &>(getObjFileLowering())
.getModuleMetadata(M);
OutStreamer->initSections(false, *TM.getMCSubtargetInfo());
// Emit the version-min deployment 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.
const Triple &Target = TM.getTargetTriple();
Triple TVT(M.getDarwinTargetVariantTriple());
OutStreamer->emitVersionForTarget(
Target, M.getSDKVersion(),
M.getDarwinTargetVariantTriple().empty() ? nullptr : &TVT,
M.getDarwinTargetVariantSDKVersion());
// 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"
SmallString<128> FileName;
if (MAI->hasBasenameOnlyForFileDirective())
FileName = llvm::sys::path::filename(M.getSourceFileName());
else
FileName = M.getSourceFileName();
if (MAI->hasFourStringsDotFile()) {
#ifdef PACKAGE_VENDOR
const char VerStr[] =
PACKAGE_VENDOR " " PACKAGE_NAME " version " PACKAGE_VERSION;
#else
const char VerStr[] = PACKAGE_NAME " version " PACKAGE_VERSION;
#endif
// TODO: Add timestamp and description.
OutStreamer->emitFileDirective(FileName, VerStr, "", "");
} else {
OutStreamer->emitFileDirective(FileName);
}
}
// On AIX, emit bytes for llvm.commandline metadata after .file so that the
// C_INFO symbol is preserved if any csect is kept by the linker.
if (TM.getTargetTriple().isOSBinFormatXCOFF())
emitModuleCommandLines(M);
GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>();
assert(MI && "AsmPrinter didn't require GCModuleInfo?");
for (const 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", *TM.getMCSubtargetInfo(),
TM.Options.MCOptions);
OutStreamer->AddComment("End of file scope inline assembly");
OutStreamer->addBlankLine();
}
if (MAI->doesSupportDebugInformation()) {
bool EmitCodeView = M.getCodeViewFlag();
if (EmitCodeView && TM.getTargetTriple().isOSWindows()) {
Handlers.emplace_back(std::make_unique<CodeViewDebug>(this),
DbgTimerName, DbgTimerDescription,
CodeViewLineTablesGroupName,
CodeViewLineTablesGroupDescription);
}
if (!EmitCodeView || M.getDwarfVersion()) {
assert(MMI && "MMI could not be nullptr here!");
if (MMI->hasDebugInfo()) {
DD = new DwarfDebug(this);
Handlers.emplace_back(std::unique_ptr<DwarfDebug>(DD), DbgTimerName,
DbgTimerDescription, DWARFGroupName,
DWARFGroupDescription);
}
}
}
if (M.getNamedMetadata(PseudoProbeDescMetadataName)) {
PP = new PseudoProbeHandler(this);
Handlers.emplace_back(std::unique_ptr<PseudoProbeHandler>(PP), PPTimerName,
PPTimerDescription, PPGroupName, PPGroupDescription);
}
switch (MAI->getExceptionHandlingType()) {
case ExceptionHandling::None:
// We may want to emit CFI for debug.
[[fallthrough]];
case ExceptionHandling::SjLj:
case ExceptionHandling::DwarfCFI:
case ExceptionHandling::ARM:
for (auto &F : M.getFunctionList()) {
if (getFunctionCFISectionType(F) != CFISection::None)
ModuleCFISection = getFunctionCFISectionType(F);
// If any function needsUnwindTableEntry(), it needs .eh_frame and hence
// the module needs .eh_frame. If we have found that case, we are done.
if (ModuleCFISection == CFISection::EH)
break;
}
assert(MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI ||
usesCFIWithoutEH() || ModuleCFISection != CFISection::EH);
break;
default:
break;
}
EHStreamer *ES = nullptr;
switch (MAI->getExceptionHandlingType()) {
case ExceptionHandling::None:
if (!usesCFIWithoutEH())
break;
[[fallthrough]];
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::Invalid:
break;
case WinEH::EncodingType::X86:
case WinEH::EncodingType::Itanium:
ES = new WinException(this);
break;
}
break;
case ExceptionHandling::Wasm:
ES = new WasmException(this);
break;
case ExceptionHandling::AIX:
ES = new AIXException(this);
break;
}
if (ES)
Handlers.emplace_back(std::unique_ptr<EHStreamer>(ES), EHTimerName,
EHTimerDescription, DWARFGroupName,
DWARFGroupDescription);
// Emit tables for any value of cfguard flag (i.e. cfguard=1 or cfguard=2).
if (mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("cfguard")))
Handlers.emplace_back(std::make_unique<WinCFGuard>(this), CFGuardName,
CFGuardDescription, DWARFGroupName,
DWARFGroupDescription);
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
HI.TimerGroupDescription, TimePassesIsEnabled);
HI.Handler->beginModule(&M);
}
if (!BasicBlockProfileDump.empty()) {
std::error_code PossibleFileError;
MBBProfileDumpFileOutput = std::make_unique<raw_fd_ostream>(
BasicBlockProfileDump, PossibleFileError);
if (PossibleFileError) {
M.getContext().emitError("Failed to open file for MBB Profile Dump: " +
PossibleFileError.message() + "\n");
}
}
return false;
}
static bool canBeHidden(const GlobalValue *GV, const MCAsmInfo &MAI) {
if (!MAI.hasWeakDefCanBeHiddenDirective())
return false;
return GV->canBeOmittedFromSymbolTable();
}
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->avoidWeakIfComdat() && GV->hasComdat()) {
// .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::ExternalLinkage:
OutStreamer->emitSymbolAttribute(GVSym, MCSA_Global);
return;
case GlobalValue::PrivateLinkage:
case GlobalValue::InternalLinkage:
return;
case GlobalValue::ExternalWeakLinkage:
case GlobalValue::AvailableExternallyLinkage:
case GlobalValue::AppendingLinkage:
llvm_unreachable("Should never emit this");
}
llvm_unreachable("Unknown linkage type!");
}
void AsmPrinter::getNameWithPrefix(SmallVectorImpl<char> &Name,
const GlobalValue *GV) const {
TM.getNameWithPrefix(Name, GV, getObjFileLowering().getMangler());
}
MCSymbol *AsmPrinter::getSymbol(const GlobalValue *GV) const {
return TM.getSymbol(GV);
}
MCSymbol *AsmPrinter::getSymbolPreferLocal(const GlobalValue &GV) const {
// On ELF, use .Lfoo$local if GV is a non-interposable GlobalObject with an
// exact definion (intersection of GlobalValue::hasExactDefinition() and
// !isInterposable()). These linkages include: external, appending, internal,
// private. It may be profitable to use a local alias for external. The
// assembler would otherwise be conservative and assume a global default
// visibility symbol can be interposable, even if the code generator already
// assumed it.
if (TM.getTargetTriple().isOSBinFormatELF() && GV.canBenefitFromLocalAlias()) {
const Module &M = *GV.getParent();
if (TM.getRelocationModel() != Reloc::Static &&
M.getPIELevel() == PIELevel::Default && GV.isDSOLocal())
return getSymbolWithGlobalValueBase(&GV, "$local");
}
return TM.getSymbol(&GV);
}
/// EmitGlobalVariable - Emit the specified global variable to the .s file.
void AsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
bool IsEmuTLSVar = TM.useEmulatedTLS() && GV->isThreadLocal();
assert(!(IsEmuTLSVar && GV->hasCommonLinkage()) &&
"No emulated TLS variables in the common section");
// Never emit TLS variable xyz in emulated TLS model.
// The initialization value is in __emutls_t.xyz instead of xyz.
if (IsEmuTLSVar)
return;
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()) {
// When printing the control variable __emutls_v.*,
// we don't need to print the original TLS variable name.
GV->printAsOperand(OutStreamer->getCommentOS(),
/*PrintType=*/false, GV->getParent());
OutStreamer->getCommentOS() << '\n';
}
}
MCSymbol *GVSym = getSymbol(GV);
MCSymbol *EmittedSym = GVSym;
// getOrCreateEmuTLSControlSym only creates the symbol with name and default
// attributes.
// GV's or GVSym's attributes will be used for the EmittedSym.
emitVisibility(EmittedSym, GV->getVisibility(), !GV->isDeclaration());
if (GV->isTagged()) {
Triple T = TM.getTargetTriple();
if (T.getArch() != Triple::aarch64 || !T.isAndroid())
OutContext.reportError(SMLoc(),
"tagged symbols (-fsanitize=memtag-globals) are "
"only supported on AArch64 Android");
OutStreamer->emitSymbolAttribute(EmittedSym, MAI->getMemtagAttr());
}
if (!GV->hasInitializer()) // External globals require no extra code.
return;
GVSym->redefineIfPossible();
if (GVSym->isDefined() || GVSym->isVariable())
OutContext.reportError(SMLoc(), "symbol '" + Twine(GVSym->getName()) +
"' is already defined");
if (MAI->hasDotTypeDotSizeDirective())
OutStreamer->emitSymbolAttribute(EmittedSym, MCSA_ELF_TypeObject);
SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
const DataLayout &DL = GV->getParent()->getDataLayout();
uint64_t Size = DL.getTypeAllocSize(GV->getValueType());
// 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).
const Align Alignment = getGVAlignment(GV, DL);
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerDescription,
HI.TimerGroupName, HI.TimerGroupDescription,
TimePassesIsEnabled);
HI.Handler->setSymbolSize(GVSym, Size);
}
// Handle common symbols
if (GVKind.isCommon()) {
if (Size == 0) Size = 1; // .comm Foo, 0 is undefined, avoid it.
// .comm _foo, 42, 4
OutStreamer->emitCommonSymbol(GVSym, Size, Alignment);
return;
}
// Determine to which section this global should be emitted.
MCSection *TheSection = getObjFileLowering().SectionForGlobal(GV, GVKind, TM);
// If we have a bss global going to a section that supports the
// zerofill directive, do so here.
if (GVKind.isBSS() && MAI->hasMachoZeroFillDirective() &&
TheSection->isVirtualSection()) {
if (Size == 0)
Size = 1; // zerofill of 0 bytes is undefined.
emitLinkage(GV, GVSym);
// .zerofill __DATA, __bss, _foo, 400, 5
OutStreamer->emitZerofill(TheSection, GVSym, Size, Alignment);
return;
}
// If this is a BSS local symbol and we are emitting in the BSS
// section use .lcomm/.comm directive.
if (GVKind.isBSSLocal() &&
getObjFileLowering().getBSSSection() == TheSection) {
if (Size == 0)
Size = 1; // .comm Foo, 0 is undefined, avoid it.
// 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, Alignment);
return;
}
// .local _foo
OutStreamer->emitSymbolAttribute(GVSym, MCSA_Local);
// .comm _foo, 42, 4
OutStreamer->emitCommonSymbol(GVSym, Size, Alignment);
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, Alignment);
} else if (GVKind.isThreadData()) {
OutStreamer->switchSection(TheSection);
emitAlignment(Alignment, GV);
OutStreamer->emitLabel(MangSym);
emitGlobalConstant(GV->getParent()->getDataLayout(),
GV->getInitializer());
}
OutStreamer->addBlankLine();
// Emit the variable struct for the runtime.
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;
}
MCSymbol *EmittedInitSym = GVSym;
OutStreamer->switchSection(TheSection);
emitLinkage(GV, EmittedInitSym);
emitAlignment(Alignment, GV);
OutStreamer->emitLabel(EmittedInitSym);
MCSymbol *LocalAlias = getSymbolPreferLocal(*GV);
if (LocalAlias != EmittedInitSym)
OutStreamer->emitLabel(LocalAlias);
emitGlobalConstant(GV->getParent()->getDataLayout(), GV->getInitializer());
if (MAI->hasDotTypeDotSizeDirective())
// .size foo, 42
OutStreamer->emitELFSize(EmittedInitSym,
MCConstantExpr::create(Size, OutContext));
OutStreamer->addBlankLine();
}
/// Emit the directive and value for debug thread local expression
///
/// \p Value - The value to emit.
/// \p Size - The size of the integer (in bytes) to emit.
void AsmPrinter::emitDebugValue(const MCExpr *Value, unsigned Size) const {
OutStreamer->emitValue(Value, Size);
}
void AsmPrinter::emitFunctionHeaderComment() {}
/// EmitFunctionHeader - This method emits the header for the current
/// function.
void AsmPrinter::emitFunctionHeader() {
const Function &F = MF->getFunction();
if (isVerbose())
OutStreamer->getCommentOS()
<< "-- Begin function "
<< GlobalValue::dropLLVMManglingEscape(F.getName()) << '\n';
// Print out constants referenced by the function
emitConstantPool();
// Print the 'header' of function.
// If basic block sections are desired, explicitly request a unique section
// for this function's entry block.
if (MF->front().isBeginSection())
MF->setSection(getObjFileLowering().getUniqueSectionForFunction(F, TM));
else
MF->setSection(getObjFileLowering().SectionForGlobal(&F, TM));
OutStreamer->switchSection(MF->getSection());
if (!MAI->hasVisibilityOnlyWithLinkage())
emitVisibility(CurrentFnSym, F.getVisibility());
if (MAI->needsFunctionDescriptors())
emitLinkage(&F, CurrentFnDescSym);
emitLinkage(&F, CurrentFnSym);
if (MAI->hasFunctionAlignment())
emitAlignment(MF->getAlignment(), &F);
if (MAI->hasDotTypeDotSizeDirective())
OutStreamer->emitSymbolAttribute(CurrentFnSym, MCSA_ELF_TypeFunction);
if (F.hasFnAttribute(Attribute::Cold))
OutStreamer->emitSymbolAttribute(CurrentFnSym, MCSA_Cold);
// Emit the prefix data.
if (F.hasPrefixData()) {
if (MAI->hasSubsectionsViaSymbols()) {
// Preserving prefix data on platforms which use subsections-via-symbols
// is a bit tricky. Here we introduce a symbol for the prefix data
// and use the .alt_entry attribute to mark the function's real entry point
// as an alternative entry point to the prefix-data symbol.
MCSymbol *PrefixSym = OutContext.createLinkerPrivateTempSymbol();
OutStreamer->emitLabel(PrefixSym);
emitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData());
// Emit an .alt_entry directive for the actual function symbol.
OutStreamer->emitSymbolAttribute(CurrentFnSym, MCSA_AltEntry);
} else {
emitGlobalConstant(F.getParent()->getDataLayout(), F.getPrefixData());
}
}
// Emit KCFI type information before patchable-function-prefix nops.
emitKCFITypeId(*MF);
// Emit M NOPs for -fpatchable-function-entry=N,M where M>0. We arbitrarily
// place prefix data before NOPs.
unsigned PatchableFunctionPrefix = 0;
unsigned PatchableFunctionEntry = 0;
(void)F.getFnAttribute("patchable-function-prefix")
.getValueAsString()
.getAsInteger(10, PatchableFunctionPrefix);
(void)F.getFnAttribute("patchable-function-entry")
.getValueAsString()
.getAsInteger(10, PatchableFunctionEntry);
if (PatchableFunctionPrefix) {
CurrentPatchableFunctionEntrySym =
OutContext.createLinkerPrivateTempSymbol();
OutStreamer->emitLabel(CurrentPatchableFunctionEntrySym);
emitNops(PatchableFunctionPrefix);
} else if (PatchableFunctionEntry) {
// May be reassigned when emitting the body, to reference the label after
// the initial BTI (AArch64) or endbr32/endbr64 (x86).
CurrentPatchableFunctionEntrySym = CurrentFnBegin;
}
// Emit the function prologue data for the indirect call sanitizer.
if (const MDNode *MD = F.getMetadata(LLVMContext::MD_func_sanitize)) {
assert(MD->getNumOperands() == 2);
auto *PrologueSig = mdconst::extract<Constant>(MD->getOperand(0));
auto *TypeHash = mdconst::extract<Constant>(MD->getOperand(1));
emitGlobalConstant(F.getParent()->getDataLayout(), PrologueSig);
emitGlobalConstant(F.getParent()->getDataLayout(), TypeHash);
}
if (isVerbose()) {
F.printAsOperand(OutStreamer->getCommentOS(),
/*PrintType=*/false, F.getParent());
emitFunctionHeaderComment();
OutStreamer->getCommentOS() << '\n';
}
// Emit the function descriptor. This is a virtual function to allow targets
// to emit their specific function descriptor. Right now it is only used by
// the AIX target. The PowerPC 64-bit V1 ELF target also uses function
// descriptors and should be converted to use this hook as well.
if (MAI->needsFunctionDescriptors())
emitFunctionDescriptor();
// 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;
takeDeletedSymbolsForFunction(&F, DeadBlockSyms);
for (MCSymbol *DeadBlockSym : DeadBlockSyms) {
OutStreamer->AddComment("Address taken block that was later removed");
OutStreamer->emitLabel(DeadBlockSym);
}
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.TimerDescription, HI.TimerGroupName,
HI.TimerGroupDescription, TimePassesIsEnabled);
HI.Handler->beginFunction(MF);
}
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
HI.TimerGroupDescription, TimePassesIsEnabled);
HI.Handler->beginBasicBlockSection(MF->front());
}
// Emit the prologue data.
if (F.hasPrologueData())
emitGlobalConstant(F.getParent()->getDataLayout(), 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");
OutStreamer->emitLabel(CurrentFnSym);
if (TM.getTargetTriple().isOSBinFormatELF()) {
MCSymbol *Sym = getSymbolPreferLocal(MF->getFunction());
if (Sym != CurrentFnSym) {
cast<MCSymbolELF>(Sym)->setType(ELF::STT_FUNC);
CurrentFnBeginLocal = Sym;
OutStreamer->emitLabel(Sym);
if (MAI->hasDotTypeDotSizeDirective())
OutStreamer->emitSymbolAttribute(Sym, MCSA_ELF_TypeFunction);
}
}
}
/// emitComments - Pretty-print comments for instructions.
static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) {
const MachineFunction *MF = MI.getMF();
const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
// Check for spills and reloads
// We assume a single instruction only has a spill or reload, not
// both.
std::optional<unsigned> Size;
if ((Size = MI.getRestoreSize(TII))) {
CommentOS << *Size << "-byte Reload\n";
} else if ((Size = MI.getFoldedRestoreSize(TII))) {
if (*Size) {
if (*Size == unsigned(MemoryLocation::UnknownSize))
CommentOS << "Unknown-size Folded Reload\n";
else
CommentOS << *Size << "-byte Folded Reload\n";
}
} else if ((Size = MI.getSpillSize(TII))) {
CommentOS << *Size << "-byte Spill\n";
} else if ((Size = MI.getFoldedSpillSize(TII))) {
if (*Size) {
if (*Size == unsigned(MemoryLocation::UnknownSize))
CommentOS << "Unknown-size Folded Spill\n";
else
CommentOS << *Size << "-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 {
Register RegNo = MI->getOperand(0).getReg();
SmallString<128> Str;
raw_svector_ostream OS(Str);
OS << "implicit-def: "
<< printReg(RegNo, MF->getSubtarget().getRegisterInfo());
OutStreamer->AddComment(OS.str());
OutStreamer->addBlankLine();
}
static void emitKill(const MachineInstr *MI, AsmPrinter &AP) {
std::string Str;
raw_string_ostream OS(Str);
OS << "kill:";
for (const MachineOperand &Op : MI->operands()) {
assert(Op.isReg() && "KILL instruction must have only register operands");
OS << ' ' << (Op.isDef() ? "def " : "killed ")
<< printReg(Op.getReg(), AP.MF->getSubtarget().getRegisterInfo());
}
AP.OutStreamer->AddComment(OS.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->isNonListDebugValue() && MI->getNumOperands() != 4)
return false;
SmallString<128> Str;
raw_svector_ostream OS(Str);
OS << "DEBUG_VALUE: ";
const DILocalVariable *V = MI->getDebugVariable();
if (auto *SP = dyn_cast<DISubprogram>(V->getScope())) {
StringRef Name = SP->getName();
if (!Name.empty())
OS << Name << ":";
}
OS << V->getName();
OS << " <- ";
const DIExpression *Expr = MI->getDebugExpression();
// First convert this to a non-variadic expression if possible, to simplify
// the output.
if (auto NonVariadicExpr = DIExpression::convertToNonVariadicExpression(Expr))
Expr = *NonVariadicExpr;
// Then, output the possibly-simplified expression.
if (Expr->getNumElements()) {
OS << '[';
ListSeparator LS;
for (auto &Op : Expr->expr_ops()) {
OS << LS << dwarf::OperationEncodingString(Op.getOp());
for (unsigned I = 0; I < Op.getNumArgs(); ++I)
OS << ' ' << Op.getArg(I);
}
OS << "] ";
}
// Register or immediate value. Register 0 means undef.
for (const MachineOperand &Op : MI->debug_operands()) {
if (&Op != MI->debug_operands().begin())
OS << ", ";
switch (Op.getType()) {
case MachineOperand::MO_FPImmediate: {
APFloat APF = APFloat(Op.getFPImm()->getValueAPF());
Type *ImmTy = Op.getFPImm()->getType();
if (ImmTy->isBFloatTy() || ImmTy->isHalfTy() || ImmTy->isFloatTy() ||
ImmTy->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();
}
break;
}
case MachineOperand::MO_Immediate: {
OS << Op.getImm();
break;
}
case MachineOperand::MO_CImmediate: {
Op.getCImm()->getValue().print(OS, false /*isSigned*/);
break;
}
case MachineOperand::MO_TargetIndex: {
OS << "!target-index(" << Op.getIndex() << "," << Op.getOffset() << ")";
break;
}
case MachineOperand::MO_Register:
case MachineOperand::MO_FrameIndex: {
Register Reg;
std::optional<StackOffset> Offset;
if (Op.isReg()) {
Reg = Op.getReg();
} else {
const TargetFrameLowering *TFI =
AP.MF->getSubtarget().getFrameLowering();
Offset = TFI->getFrameIndexReference(*AP.MF, Op.getIndex(), Reg);
}
if (!Reg) {
// Suppress offset, it is not meaningful here.
OS << "undef";
break;
}
// The second operand is only an offset if it's an immediate.
if (MI->isIndirectDebugValue())
Offset = StackOffset::getFixed(MI->getDebugOffset().getImm());
if (Offset)
OS << '[';
OS << printReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
if (Offset)
OS << '+' << Offset->getFixed() << ']';
break;
}
default:
llvm_unreachable("Unknown operand type");
}
}
// NOTE: Want this comment at start of line, don't emit with AddComment.
AP.OutStreamer->emitRawComment(OS.str());
return true;
}
/// This method handles the target-independent form of DBG_LABEL, returning
/// true if it was able to do so. A false return means the target will need
/// to handle MI in EmitInstruction.
static bool emitDebugLabelComment(const MachineInstr *MI, AsmPrinter &AP) {
if (MI->getNumOperands() != 1)
return false;
SmallString<128> Str;
raw_svector_ostream OS(Str);
OS << "DEBUG_LABEL: ";
const DILabel *V = MI->getDebugLabel();
if (auto *SP = dyn_cast<DISubprogram>(
V->getScope()->getNonLexicalBlockFileScope())) {
StringRef Name = SP->getName();
if (!Name.empty())
OS << Name << ":";
}
OS << V->getName();
// NOTE: Want this comment at start of line, don't emit with AddComment.
AP.OutStreamer->emitRawComment(OS.str());
return true;
}
AsmPrinter::CFISection
AsmPrinter::getFunctionCFISectionType(const Function &F) const {
// Ignore functions that won't get emitted.
if (F.isDeclarationForLinker())
return CFISection::None;
if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI &&
F.needsUnwindTableEntry())
return CFISection::EH;
if (MAI->usesCFIWithoutEH() && F.hasUWTable())
return CFISection::EH;
assert(MMI != nullptr && "Invalid machine module info");
if (MMI->hasDebugInfo() || TM.Options.ForceDwarfFrameSection)
return CFISection::Debug;
return CFISection::None;
}
AsmPrinter::CFISection
AsmPrinter::getFunctionCFISectionType(const MachineFunction &MF) const {
return getFunctionCFISectionType(MF.getFunction());
}
bool AsmPrinter::needsSEHMoves() {
return MAI->usesWindowsCFI() && MF->getFunction().needsUnwindTableEntry();
}
bool AsmPrinter::usesCFIWithoutEH() const {
return MAI->usesCFIWithoutEH() && ModuleCFISection != CFISection::None;
}
void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) {
ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
if (!usesCFIWithoutEH() &&
ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
ExceptionHandlingType != ExceptionHandling::ARM)
return;
if (getFunctionCFISectionType(*MF) == CFISection::None)
return;
// If there is no "real" instruction following this CFI instruction, skip
// emitting it; it would be beyond the end of the function's FDE range.
auto *MBB = MI.getParent();
auto I = std::next(MI.getIterator());
while (I != MBB->end() && I->isTransient())
++I;
if (I == MBB->instr_end() &&
MBB->getReverseIterator() == MBB->getParent()->rbegin())
return;
const std::vector<MCCFIInstruction> &Instrs = MF->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));
}
/// Returns the BB metadata to be emitted in the SHT_LLVM_BB_ADDR_MAP section
/// for a given basic block. This can be used to capture more precise profile
/// information.
static uint32_t getBBAddrMapMetadata(const MachineBasicBlock &MBB) {
const TargetInstrInfo *TII = MBB.getParent()->getSubtarget().getInstrInfo();
return object::BBAddrMap::BBEntry::Metadata{
MBB.isReturnBlock(), !MBB.empty() && TII->isTailCall(MBB.back()),
MBB.isEHPad(), const_cast<MachineBasicBlock &>(MBB).canFallThrough(),
!MBB.empty() && MBB.rbegin()->isIndirectBranch()}
.encode();
}
void AsmPrinter::emitBBAddrMapSection(const MachineFunction &MF) {
MCSection *BBAddrMapSection =
getObjFileLowering().getBBAddrMapSection(*MF.getSection());
assert(BBAddrMapSection && ".llvm_bb_addr_map section is not initialized.");
const MCSymbol *FunctionSymbol = getFunctionBegin();
OutStreamer->pushSection();
OutStreamer->switchSection(BBAddrMapSection);
OutStreamer->AddComment("version");
uint8_t BBAddrMapVersion = OutStreamer->getContext().getBBAddrMapVersion();
OutStreamer->emitInt8(BBAddrMapVersion);
OutStreamer->AddComment("feature");
OutStreamer->emitInt8(0);
OutStreamer->AddComment("function address");
OutStreamer->emitSymbolValue(FunctionSymbol, getPointerSize());
OutStreamer->AddComment("number of basic blocks");
OutStreamer->emitULEB128IntValue(MF.size());
const MCSymbol *PrevMBBEndSymbol = FunctionSymbol;
// Emit BB Information for each basic block in the function.
for (const MachineBasicBlock &MBB : MF) {
const MCSymbol *MBBSymbol =
MBB.isEntryBlock() ? FunctionSymbol : MBB.getSymbol();
// TODO: Remove this check when version 1 is deprecated.
if (BBAddrMapVersion > 1) {
OutStreamer->AddComment("BB id");
// Emit the BB ID for this basic block.
OutStreamer->emitULEB128IntValue(*MBB.getBBID());
}
// Emit the basic block offset relative to the end of the previous block.
// This is zero unless the block is padded due to alignment.
emitLabelDifferenceAsULEB128(MBBSymbol, PrevMBBEndSymbol);
// Emit the basic block size. When BBs have alignments, their size cannot
// always be computed from their offsets.
emitLabelDifferenceAsULEB128(MBB.getEndSymbol(), MBBSymbol);
// Emit the Metadata.
OutStreamer->emitULEB128IntValue(getBBAddrMapMetadata(MBB));
PrevMBBEndSymbol = MBB.getEndSymbol();
}
OutStreamer->popSection();
}
void AsmPrinter::emitKCFITrapEntry(const MachineFunction &MF,
const MCSymbol *Symbol) {
MCSection *Section =
getObjFileLowering().getKCFITrapSection(*MF.getSection());
if (!Section)
return;
OutStreamer->pushSection();
OutStreamer->switchSection(Section);
MCSymbol *Loc = OutContext.createLinkerPrivateTempSymbol();
OutStreamer->emitLabel(Loc);
OutStreamer->emitAbsoluteSymbolDiff(Symbol, Loc, 4);
OutStreamer->popSection();
}
void AsmPrinter::emitKCFITypeId(const MachineFunction &MF) {
const Function &F = MF.getFunction();
if (const MDNode *MD = F.getMetadata(LLVMContext::MD_kcfi_type))
emitGlobalConstant(F.getParent()->getDataLayout(),
mdconst::extract<ConstantInt>(MD->getOperand(0)));
}
void AsmPrinter::emitPseudoProbe(const MachineInstr &MI) {
if (PP) {
auto GUID = MI.getOperand(0).getImm();
auto Index = MI.getOperand(1).getImm();
auto Type = MI.getOperand(2).getImm();
auto Attr = MI.getOperand(3).getImm();
DILocation *DebugLoc = MI.getDebugLoc();
PP->emitPseudoProbe(GUID, Index, Type, Attr, DebugLoc);
}
}
void AsmPrinter::emitStackSizeSection(const MachineFunction &MF) {
if (!MF.getTarget().Options.EmitStackSizeSection)
return;
MCSection *StackSizeSection =
getObjFileLowering().getStackSizesSection(*getCurrentSection());
if (!StackSizeSection)
return;
const MachineFrameInfo &FrameInfo = MF.getFrameInfo();
// Don't emit functions with dynamic stack allocations.
if (FrameInfo.hasVarSizedObjects())
return;
OutStreamer->pushSection();
OutStreamer->switchSection(StackSizeSection);
const MCSymbol *FunctionSymbol = getFunctionBegin();
uint64_t StackSize =
FrameInfo.getStackSize() + FrameInfo.getUnsafeStackSize();
OutStreamer->emitSymbolValue(FunctionSymbol, TM.getProgramPointerSize());
OutStreamer->emitULEB128IntValue(StackSize);
OutStreamer->popSection();
}
void AsmPrinter::emitStackUsage(const MachineFunction &MF) {
const std::string &OutputFilename = MF.getTarget().Options.StackUsageOutput;
// OutputFilename empty implies -fstack-usage is not passed.
if (OutputFilename.empty())
return;
const MachineFrameInfo &FrameInfo = MF.getFrameInfo();
uint64_t StackSize =
FrameInfo.getStackSize() + FrameInfo.getUnsafeStackSize();
if (StackUsageStream == nullptr) {
std::error_code EC;
StackUsageStream =
std::make_unique<raw_fd_ostream>(OutputFilename, EC, sys::fs::OF_Text);
if (EC) {
errs() << "Could not open file: " << EC.message();
return;
}
}
*StackUsageStream << MF.getFunction().getParent()->getName();
if (const DISubprogram *DSP = MF.getFunction().getSubprogram())
*StackUsageStream << ':' << DSP->getLine();
*StackUsageStream << ':' << MF.getName() << '\t' << StackSize << '\t';
if (FrameInfo.hasVarSizedObjects())
*StackUsageStream << "dynamic\n";
else
*StackUsageStream << "static\n";
}
void AsmPrinter::emitPCSectionsLabel(const MachineFunction &MF,
const MDNode &MD) {
MCSymbol *S = MF.getContext().createTempSymbol("pcsection");
OutStreamer->emitLabel(S);
PCSectionsSymbols[&MD].emplace_back(S);
}
void AsmPrinter::emitPCSections(const MachineFunction &MF) {
const Function &F = MF.getFunction();
if (PCSectionsSymbols.empty() && !F.hasMetadata(LLVMContext::MD_pcsections))
return;
const CodeModel::Model CM = MF.getTarget().getCodeModel();
const unsigned RelativeRelocSize =
(CM == CodeModel::Medium || CM == CodeModel::Large) ? getPointerSize()
: 4;
// Switch to PCSection, short-circuiting the common case where the current
// section is still valid (assume most MD_pcsections contain just 1 section).
auto SwitchSection = [&, Prev = StringRef()](const StringRef &Sec) mutable {
if (Sec == Prev)
return;
MCSection *S = getObjFileLowering().getPCSection(Sec, MF.getSection());
assert(S && "PC section is not initialized");
OutStreamer->switchSection(S);
Prev = Sec;
};
// Emit symbols into sections and data as specified in the pcsections MDNode.
auto EmitForMD = [&](const MDNode &MD, ArrayRef<const MCSymbol *> Syms,
bool Deltas) {
// Expect the first operand to be a section name. After that, a tuple of
// constants may appear, which will simply be emitted into the current
// section (the user of MD_pcsections decides the format of encoded data).
assert(isa<MDString>(MD.getOperand(0)) && "first operand not a string");
bool ConstULEB128 = false;
for (const MDOperand &MDO : MD.operands()) {
if (auto *S = dyn_cast<MDString>(MDO)) {
// Found string, start of new section!
// Find options for this section "<section>!<opts>" - supported options:
// C = Compress constant integers of size 2-8 bytes as ULEB128.
const StringRef SecWithOpt = S->getString();
const size_t OptStart = SecWithOpt.find('!'); // likely npos
const StringRef Sec = SecWithOpt.substr(0, OptStart);
const StringRef Opts = SecWithOpt.substr(OptStart); // likely empty
ConstULEB128 = Opts.find('C') != StringRef::npos;
#ifndef NDEBUG
for (char O : Opts)
assert((O == '!' || O == 'C') && "Invalid !pcsections options");
#endif
SwitchSection(Sec);
const MCSymbol *Prev = Syms.front();
for (const MCSymbol *Sym : Syms) {
if (Sym == Prev || !Deltas) {
// Use the entry itself as the base of the relative offset.
MCSymbol *Base = MF.getContext().createTempSymbol("pcsection_base");
OutStreamer->emitLabel(Base);
// Emit relative relocation `addr - base`, which avoids a dynamic
// relocation in the final binary. User will get the address with
// `base + addr`.
emitLabelDifference(Sym, Base, RelativeRelocSize);
} else {
// Emit delta between symbol and previous symbol.
if (ConstULEB128)
emitLabelDifferenceAsULEB128(Sym, Prev);
else
emitLabelDifference(Sym, Prev, 4);
}
Prev = Sym;
}
} else {
// Emit auxiliary data after PC.
assert(isa<MDNode>(MDO) && "expecting either string or tuple");
const auto *AuxMDs = cast<MDNode>(MDO);
for (const MDOperand &AuxMDO : AuxMDs->operands()) {
assert(isa<ConstantAsMetadata>(AuxMDO) && "expecting a constant");
const Constant *C = cast<ConstantAsMetadata>(AuxMDO)->getValue();
const DataLayout &DL = F.getParent()->getDataLayout();
const uint64_t Size = DL.getTypeStoreSize(C->getType());
if (auto *CI = dyn_cast<ConstantInt>(C);
CI && ConstULEB128 && Size > 1 && Size <= 8) {
emitULEB128(CI->getZExtValue());
} else {
emitGlobalConstant(DL, C);
}
}
}
}
};
OutStreamer->pushSection();
// Emit PCs for function start and function size.
if (const MDNode *MD = F.getMetadata(LLVMContext::MD_pcsections))
EmitForMD(*MD, {getFunctionBegin(), getFunctionEnd()}, true);
// Emit PCs for instructions collected.
for (const auto &MS : PCSectionsSymbols)
EmitForMD(*MS.first, MS.second, false);
OutStreamer->popSection();
PCSectionsSymbols.clear();
}
/// Returns true if function begin and end labels should be emitted.
static bool needFuncLabels(const MachineFunction &MF) {
MachineModuleInfo &MMI = MF.getMMI();
if (!MF.getLandingPads().empty() || MF.hasEHFunclets() ||
MMI.hasDebugInfo() ||
MF.getFunction().hasMetadata(LLVMContext::MD_pcsections))
return true;
// We might emit an EH table that uses function begin and end labels even if
// we don't have any landingpads.
if (!MF.getFunction().hasPersonalityFn())
return false;
return !isNoOpWithoutInvoke(
classifyEHPersonality(MF.getFunction().getPersonalityFn()));
}
/// EmitFunctionBody - This method emits the body and trailer for a
/// function.
void AsmPrinter::emitFunctionBody() {
emitFunctionHeader();
// Emit target-specific gunk before the function body.
emitFunctionBodyStart();
if (isVerbose()) {
// Get MachineDominatorTree or compute it on the fly if it's unavailable
MDT = getAnalysisIfAvailable<MachineDominatorTree>();
if (!MDT) {
OwnedMDT = std::make_unique<MachineDominatorTree>();
OwnedMDT->getBase().recalculate(*MF);
MDT = OwnedMDT.get();
}
// Get MachineLoopInfo or compute it on the fly if it's unavailable
MLI = getAnalysisIfAvailable<MachineLoopInfo>();
if (!MLI) {
OwnedMLI = std::make_unique<MachineLoopInfo>();
OwnedMLI->getBase().analyze(MDT->getBase());
MLI = OwnedMLI.get();
}
}
// Print out code for the function.
bool HasAnyRealCode = false;
int NumInstsInFunction = 0;
bool IsEHa = MMI->getModule()->getModuleFlag("eh-asynch");
bool CanDoExtraAnalysis = ORE->allowExtraAnalysis(DEBUG_TYPE);
for (auto &MBB : *MF) {
// Print a label for the basic block.
emitBasicBlockStart(MBB);
DenseMap<StringRef, unsigned> MnemonicCounts;
for (auto &MI : MBB) {
// Print the assembly for the instruction.
if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() &&
!MI.isDebugInstr()) {
HasAnyRealCode = true;
++NumInstsInFunction;
}
// If there is a pre-instruction symbol, emit a label for it here.
if (MCSymbol *S = MI.getPreInstrSymbol())
OutStreamer->emitLabel(S);
if (MDNode *MD = MI.getPCSections())
emitPCSectionsLabel(*MF, *MD);
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
HI.TimerGroupDescription, TimePassesIsEnabled);
HI.Handler->beginInstruction(&MI);
}
if (isVerbose())
emitComments(MI, OutStreamer->getCommentOS());
switch (MI.getOpcode()) {
case TargetOpcode::CFI_INSTRUCTION:
emitCFIInstruction(MI);
break;
case TargetOpcode::LOCAL_ESCAPE:
emitFrameAlloc(MI);
break;
case TargetOpcode::ANNOTATION_LABEL:
case TargetOpcode::GC_LABEL:
OutStreamer->emitLabel(MI.getOperand(0).getMCSymbol());
break;
case TargetOpcode::EH_LABEL:
OutStreamer->emitLabel(MI.getOperand(0).getMCSymbol());
// For AsynchEH, insert a Nop if followed by a trap inst
// Or the exception won't be caught.
// (see MCConstantExpr::create(1,..) in WinException.cpp)
// Ignore SDiv/UDiv because a DIV with Const-0 divisor
// must have being turned into an UndefValue.
// Div with variable opnds won't be the first instruction in
// an EH region as it must be led by at least a Load
{
auto MI2 = std::next(MI.getIterator());
if (IsEHa && MI2 != MBB.end() &&
(MI2->mayLoadOrStore() || MI2->mayRaiseFPException()))
emitNops(1);
}
break;
case TargetOpcode::INLINEASM:
case TargetOpcode::INLINEASM_BR:
emitInlineAsm(&MI);
break;
case TargetOpcode::DBG_VALUE:
case TargetOpcode::DBG_VALUE_LIST:
if (isVerbose()) {
if (!emitDebugValueComment(&MI, *this))
emitInstruction(&MI);
}
break;
case TargetOpcode::DBG_INSTR_REF:
// This instruction reference will have been resolved to a machine
// location, and a nearby DBG_VALUE created. We can safely ignore
// the instruction reference.
break;
case TargetOpcode::DBG_PHI:
// This instruction is only used to label a program point, it's purely
// meta information.
break;
case TargetOpcode::DBG_LABEL:
if (isVerbose()) {
if (!emitDebugLabelComment(&MI, *this))
emitInstruction(&MI);
}
break;
case TargetOpcode::IMPLICIT_DEF:
if (isVerbose()) emitImplicitDef(&MI);
break;
case TargetOpcode::KILL:
if (isVerbose()) emitKill(&MI, *this);
break;
case TargetOpcode::PSEUDO_PROBE:
emitPseudoProbe(MI);
break;
case TargetOpcode::ARITH_FENCE:
if (isVerbose())
OutStreamer->emitRawComment("ARITH_FENCE");
break;
case TargetOpcode::MEMBARRIER:
OutStreamer->emitRawComment("MEMBARRIER");
break;
case TargetOpcode::JUMP_TABLE_DEBUG_INFO:
// This instruction is only used to note jump table debug info, it's
// purely meta information.
break;
default:
emitInstruction(&MI);
if (CanDoExtraAnalysis) {
MCInst MCI;
MCI.setOpcode(MI.getOpcode());
auto Name = OutStreamer->getMnemonic(MCI);
auto I = MnemonicCounts.insert({Name, 0u});
I.first->second++;
}
break;
}
// If there is a post-instruction symbol, emit a label for it here.
if (MCSymbol *S = MI.getPostInstrSymbol())
OutStreamer->emitLabel(S);
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
HI.TimerGroupDescription, TimePassesIsEnabled);
HI.Handler->endInstruction();
}
}
// We must emit temporary symbol for the end of this basic block, if either
// we have BBLabels enabled or if this basic blocks marks the end of a
// section.
if (MF->hasBBLabels() ||
(MAI->hasDotTypeDotSizeDirective() && MBB.isEndSection()))
OutStreamer->emitLabel(MBB.getEndSymbol());
if (MBB.isEndSection()) {
// The size directive for the section containing the entry block is
// handled separately by the function section.
if (!MBB.sameSection(&MF->front())) {
if (MAI->hasDotTypeDotSizeDirective()) {
// Emit the size directive for the basic block section.
const MCExpr *SizeExp = MCBinaryExpr::createSub(
MCSymbolRefExpr::create(MBB.getEndSymbol(), OutContext),
MCSymbolRefExpr::create(CurrentSectionBeginSym, OutContext),
OutContext);
OutStreamer->emitELFSize(CurrentSectionBeginSym, SizeExp);
}
MBBSectionRanges[MBB.getSectionIDNum()] =
MBBSectionRange{CurrentSectionBeginSym, MBB.getEndSymbol()};
}
}
emitBasicBlockEnd(MBB);
if (CanDoExtraAnalysis) {
// Skip empty blocks.
if (MBB.empty())
continue;
MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionMix",
MBB.begin()->getDebugLoc(), &MBB);
// Generate instruction mix remark. First, sort counts in descending order
// by count and name.
SmallVector<std::pair<StringRef, unsigned>, 128> MnemonicVec;
for (auto &KV : MnemonicCounts)
MnemonicVec.emplace_back(KV.first, KV.second);
sort(MnemonicVec, [](const std::pair<StringRef, unsigned> &A,
const std::pair<StringRef, unsigned> &B) {
if (A.second > B.second)
return true;
if (A.second == B.second)
return StringRef(A.first) < StringRef(B.first);
return false;
});
R << "BasicBlock: " << ore::NV("BasicBlock", MBB.getName()) << "\n";
for (auto &KV : MnemonicVec) {
auto Name = (Twine("INST_") + getToken(KV.first.trim()).first).str();
R << KV.first << ": " << ore::NV(Name, KV.second) << "\n";
}
ORE->emit(R);
}
}
EmittedInsts += NumInstsInFunction;
MachineOptimizationRemarkAnalysis R(DEBUG_TYPE, "InstructionCount",
MF->getFunction().getSubprogram(),
&MF->front());
R << ore::NV("NumInstructions", NumInstsInFunction)
<< " instructions in function";
ORE->emit(R);
// 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.
// Similarly, don't emit empty functions on Windows either. It can lead to
// duplicate entries (two functions with the same RVA) in the Guard CF Table
// after linking, causing the kernel not to load the binary:
// https://developercommunity.visualstudio.com/content/problem/45366/vc-linker-creates-invalid-dll-with-clang-cl.html
// FIXME: Hide this behind some API in e.g. MCAsmInfo or MCTargetStreamer.
const Triple &TT = TM.getTargetTriple();
if (!HasAnyRealCode && (MAI->hasSubsectionsViaSymbols() ||
(TT.isOSWindows() && TT.isOSBinFormatCOFF()))) {
MCInst Noop = MF->getSubtarget().getInstrInfo()->getNop();
// Targets can opt-out of emitting the noop here by leaving the opcode
// unspecified.
if (Noop.getOpcode()) {
OutStreamer->AddComment("avoids zero-length function");
emitNops(1);
}
}
// Switch to the original section in case basic block sections was used.
OutStreamer->switchSection(MF->getSection());
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();
// Even though wasm supports .type and .size in general, function symbols
// are automatically sized.
bool EmitFunctionSize = MAI->hasDotTypeDotSizeDirective() && !TT.isWasm();
if (needFuncLabels(*MF) || EmitFunctionSize) {
// Create a symbol for the end of function.
CurrentFnEnd = createTempSymbol("func_end");
OutStreamer->emitLabel(CurrentFnEnd);
}
// If the target wants a .size directive for the size of the function, emit
// it.
if (EmitFunctionSize) {
// 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);
if (CurrentFnBeginLocal)
OutStreamer->emitELFSize(CurrentFnBeginLocal, SizeExp);
}
// Call endBasicBlockSection on the last block now, if it wasn't already
// called.
if (!MF->back().isEndSection()) {
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
HI.TimerGroupDescription, TimePassesIsEnabled);
HI.Handler->endBasicBlockSection(MF->back());
}
}
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
HI.TimerGroupDescription, TimePassesIsEnabled);
HI.Handler->markFunctionEnd();
}
MBBSectionRanges[MF->front().getSectionIDNum()] =
MBBSectionRange{CurrentFnBegin, CurrentFnEnd};
// 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.TimerDescription, HI.TimerGroupName,
HI.TimerGroupDescription, TimePassesIsEnabled);
HI.Handler->endFunction(MF);
}
// Emit section containing BB address offsets and their metadata, when
// BB labels are requested for this function. Skip empty functions.
if (MF->hasBBLabels() && HasAnyRealCode)
emitBBAddrMapSection(*MF);
// Emit sections containing instruction and function PCs.
emitPCSections(*MF);
// Emit section containing stack size metadata.
emitStackSizeSection(*MF);
// Emit .su file containing function stack size information.
emitStackUsage(*MF);
emitPatchableFunctionEntries();
if (isVerbose())
OutStreamer->getCommentOS() << "-- End function\n";
OutStreamer->addBlankLine();
// Output MBB ids, function names, and frequencies if the flag to dump
// MBB profile information has been set
if (MBBProfileDumpFileOutput && !MF->empty() &&
MF->getFunction().getEntryCount()) {
if (!MF->hasBBLabels())
MF->getContext().reportError(
SMLoc(),
"Unable to find BB labels for MBB profile dump. -mbb-profile-dump "
"must be called with -basic-block-sections=labels");
MachineBlockFrequencyInfo &MBFI =
getAnalysis<LazyMachineBlockFrequencyInfoPass>().getBFI();
// The entry count and the entry basic block frequency aren't the same. We
// want to capture "absolute" frequencies, i.e. the frequency with which a
// MBB is executed when the program is executed. From there, we can derive
// Function-relative frequencies (divide by the value for the first MBB).
// We also have the information about frequency with which functions
// were called. This helps, for example, in a type of integration tests
// where we want to cross-validate the compiler's profile with a real
// profile.
// Using double precision because uint64 values used to encode mbb
// "frequencies" may be quite large.
const double EntryCount =
static_cast<double>(MF->getFunction().getEntryCount()->getCount());
for (const auto &MBB : *MF) {
const double MBBRelFreq = MBFI.getBlockFreqRelativeToEntryBlock(&MBB);
const double AbsMBBFreq = MBBRelFreq * EntryCount;
*MBBProfileDumpFileOutput.get()
<< MF->getName() << "," << MBB.getBBID() << "," << AbsMBBFreq << "\n";
}
}
}
/// 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 (const auto *CU : C->users())
NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU));
return NumUses;
}
/// 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->hasGlobalUnnamedAddr() || !GV->hasInitializer() ||
!GV->isConstant() || !GV->isDiscardableIfUnused() ||
!isa<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 (const auto *U : GV->users())
NumGOTEquivUsers += getNumGlobalVariableUses(dyn_cast<Constant>(U));
return NumGOTEquivUsers > 0;
}
/// 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);
}
}
/// 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;
SmallVector<const GlobalVariable *, 8> FailedCandidates;
for (auto &I : GlobalGOTEquivs) {
const GlobalVariable *GV = I.second.first;
unsigned Cnt = I.second.second;
if (Cnt)
FailedCandidates.push_back(GV);
}
GlobalGOTEquivs.clear();
for (const auto *GV : FailedCandidates)
emitGlobalVariable(GV);
}
void AsmPrinter::emitGlobalAlias(Module &M, const GlobalAlias &GA) {
MCSymbol *Name = getSymbol(&GA);
bool IsFunction = GA.getValueType()->isFunctionTy();
// Treat bitcasts of functions as functions also. This is important at least
// on WebAssembly where object and function addresses can't alias each other.
if (!IsFunction)
IsFunction = isa<Function>(GA.getAliasee()->stripPointerCasts());
// AIX's assembly directive `.set` is not usable for aliasing purpose,
// so AIX has to use the extra-label-at-definition strategy. At this
// point, all the extra label is emitted, we just have to emit linkage for
// those labels.
if (TM.getTargetTriple().isOSBinFormatXCOFF()) {
assert(MAI->hasVisibilityOnlyWithLinkage() &&
"Visibility should be handled with emitLinkage() on AIX.");
// Linkage for alias of global variable has been emitted.
if (isa<GlobalVariable>(GA.getAliaseeObject()))
return;
emitLinkage(&GA, Name);
// If it's a function, also emit linkage for aliases of function entry
// point.
if (IsFunction)
emitLinkage(&GA,
getObjFileLowering().getFunctionEntryPointSymbol(&GA, TM));
return;
}
if (GA.hasExternalLinkage() || !MAI->getWeakRefDirective())
OutStreamer->emitSymbolAttribute(Name, MCSA_Global);
else if (GA.hasWeakLinkage() || GA.hasLinkOnceLinkage())
OutStreamer->emitSymbolAttribute(Name, MCSA_WeakReference);
else
assert(GA.hasLocalLinkage() && "Invalid alias linkage");
// Set the symbol type to function if the alias has a function type.
// This affects codegen when the aliasee is not a function.
if (IsFunction) {
OutStreamer->emitSymbolAttribute(Name, MCSA_ELF_TypeFunction);
if (TM.getTargetTriple().isOSBinFormatCOFF()) {
OutStreamer->beginCOFFSymbolDef(Name);
OutStreamer->emitCOFFSymbolStorageClass(
GA.hasLocalLinkage() ? COFF::IMAGE_SYM_CLASS_STATIC
: COFF::IMAGE_SYM_CLASS_EXTERNAL);
OutStreamer->emitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
<< COFF::SCT_COMPLEX_TYPE_SHIFT);
OutStreamer->endCOFFSymbolDef();
}
}
emitVisibility(Name, GA.getVisibility());
const MCExpr *Expr = lowerConstant(GA.getAliasee());
if (MAI->hasAltEntry() && isa<MCBinaryExpr>(Expr))
OutStreamer->emitSymbolAttribute(Name, MCSA_AltEntry);
// Emit the directives as assignments aka .set:
OutStreamer->emitAssignment(Name, Expr);
MCSymbol *LocalAlias = getSymbolPreferLocal(GA);
if (LocalAlias != Name)
OutStreamer->emitAssignment(LocalAlias, Expr);
// If the aliasee does not correspond to a symbol in the output, i.e. the
// alias is not of an object or the aliased object is private, then set the
// size of the alias symbol from the type of the alias. We don't do this in
// other situations as the alias and aliasee having differing types but same
// size may be intentional.
const GlobalObject *BaseObject = GA.getAliaseeObject();
if (MAI->hasDotTypeDotSizeDirective() && GA.getValueType()->isSized() &&
(!BaseObject || BaseObject->hasPrivateLinkage())) {
const DataLayout &DL = M.getDataLayout();
uint64_t Size = DL.getTypeAllocSize(GA.getValueType());
OutStreamer->emitELFSize(Name, MCConstantExpr::create(Size, OutContext));
}
}
void AsmPrinter::emitGlobalIFunc(Module &M, const GlobalIFunc &GI) {
assert(!TM.getTargetTriple().isOSBinFormatXCOFF() &&
"IFunc is not supported on AIX.");
MCSymbol *Name = getSymbol(&GI);
if (GI.hasExternalLinkage() || !MAI->getWeakRefDirective())
OutStreamer->emitSymbolAttribute(Name, MCSA_Global);
else if (GI.hasWeakLinkage() || GI.hasLinkOnceLinkage())
OutStreamer->emitSymbolAttribute(Name, MCSA_WeakReference);
else
assert(GI.hasLocalLinkage() && "Invalid ifunc linkage");
OutStreamer->emitSymbolAttribute(Name, MCSA_ELF_TypeIndFunction);
emitVisibility(Name, GI.getVisibility());
// Emit the directives as assignments aka .set:
const MCExpr *Expr = lowerConstant(GI.getResolver());
OutStreamer->emitAssignment(Name, Expr);
MCSymbol *LocalAlias = getSymbolPreferLocal(GI);
if (LocalAlias != Name)
OutStreamer->emitAssignment(LocalAlias, Expr);
}
void AsmPrinter::emitRemarksSection(remarks::RemarkStreamer &RS) {
if (!RS.needsSection())
return;
remarks::RemarkSerializer &RemarkSerializer = RS.getSerializer();
std::optional<SmallString<128>> Filename;
if (std::optional<StringRef> FilenameRef = RS.getFilename()) {
Filename = *FilenameRef;
sys::fs::make_absolute(*Filename);
assert(!Filename->empty() && "The filename can't be empty.");
}
std::string Buf;
raw_string_ostream OS(Buf);
std::unique_ptr<remarks::MetaSerializer> MetaSerializer =
Filename ? RemarkSerializer.metaSerializer(OS, Filename->str())
: RemarkSerializer.metaSerializer(OS);
MetaSerializer->emit();
// Switch to the remarks section.
MCSection *RemarksSection =
OutContext.getObjectFileInfo()->getRemarksSection();
OutStreamer->switchSection(RemarksSection);
OutStreamer->emitBinaryData(OS.str());
}
bool AsmPrinter::doFinalization(Module &M) {
// Set the MachineFunction to nullptr so that we can catch attempted
// accesses to MF specific features at the module level and so that
// we can conditionalize accesses based on whether or not it is nullptr.
MF = nullptr;
// 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();
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
// Emit linkage(XCOFF) and visibility info for declarations
for (const Function &F : M) {
if (!F.isDeclarationForLinker())
continue;
MCSymbol *Name = getSymbol(&F);
// Function getSymbol gives us the function descriptor symbol for XCOFF.
if (!TM.getTargetTriple().isOSBinFormatXCOFF()) {
GlobalValue::VisibilityTypes V = F.getVisibility();
if (V == GlobalValue::DefaultVisibility)
continue;
emitVisibility(Name, V, false);
continue;
}
if (F.isIntrinsic())
continue;
// Handle the XCOFF case.
// Variable `Name` is the function descriptor symbol (see above). Get the
// function entry point symbol.
MCSymbol *FnEntryPointSym = TLOF.getFunctionEntryPointSymbol(&F, TM);
// Emit linkage for the function entry point.
emitLinkage(&F, FnEntryPointSym);
// Emit linkage for the function descriptor.
emitLinkage(&F, Name);
}
// Emit the remarks section contents.
// FIXME: Figure out when is the safest time to emit this section. It should
// not come after debug info.
if (remarks::RemarkStreamer *RS = M.getContext().getMainRemarkStreamer())
emitRemarksSection(*RS);
TLOF.emitModuleMetadata(*OutStreamer, M);
if (TM.getTargetTriple().isOSBinFormatELF()) {
MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
// Output stubs for external and common global variables.
MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
if (!Stubs.empty()) {
OutStreamer->switchSection(TLOF.getDataSection());
const DataLayout &DL = M.getDataLayout();
emitAlignment(Align(DL.getPointerSize()));
for (const auto &Stub : Stubs) {
OutStreamer->emitLabel(Stub.first);
OutStreamer->emitSymbolValue(Stub.second.getPointer(),
DL.getPointerSize());
}
}
}
if (TM.getTargetTriple().isOSBinFormatCOFF()) {
MachineModuleInfoCOFF &MMICOFF =
MMI->getObjFileInfo<MachineModuleInfoCOFF>();
// Output stubs for external and common global variables.
MachineModuleInfoCOFF::SymbolListTy Stubs = MMICOFF.GetGVStubList();
if (!Stubs.empty()) {
const DataLayout &DL = M.getDataLayout();
for (const auto &Stub : Stubs) {
SmallString<256> SectionName = StringRef(".rdata$");
SectionName += Stub.first->getName();
OutStreamer->switchSection(OutContext.getCOFFSection(
SectionName,
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_LNK_COMDAT,
SectionKind::getReadOnly(), Stub.first->getName(),
COFF::IMAGE_COMDAT_SELECT_ANY));
emitAlignment(Align(DL.getPointerSize()));
OutStreamer->emitSymbolAttribute(Stub.first, MCSA_Global);
OutStreamer->emitLabel(Stub.first);
OutStreamer->emitSymbolValue(Stub.second.getPointer(),
DL.getPointerSize());
}
}
}
// This needs to happen before emitting debug information since that can end
// arbitrary sections.
if (auto *TS = OutStreamer->getTargetStreamer())
TS->emitConstantPools();
// Emit Stack maps before any debug info. Mach-O requires that no data or
// text sections come after debug info has been emitted. This matters for
// stack maps as they are arbitrary data, and may even have a custom format
// through user plugins.
emitStackMaps();
// Finalize debug and EH information.
for (const HandlerInfo &HI : Handlers) {
NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName,
HI.TimerGroupDescription, TimePassesIsEnabled);
HI.Handler->endModule();
}
// This deletes all the ephemeral handlers that AsmPrinter added, while
// keeping all the user-added handlers alive until the AsmPrinter is
// destroyed.
Handlers.erase(Handlers.begin() + NumUserHandlers, Handlers.end());
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 objects here.
for (const auto &GO : M.global_objects()) {
if (!GO.hasExternalWeakLinkage())
continue;
OutStreamer->emitSymbolAttribute(getSymbol(&GO), MCSA_WeakReference);
}
if (shouldEmitWeakSwiftAsyncExtendedFramePointerFlags()) {
auto SymbolName = "swift_async_extendedFramePointerFlags";
auto Global = M.getGlobalVariable(SymbolName);
if (!Global) {
auto Int8PtrTy = Type::getInt8PtrTy(M.getContext());
Global = new GlobalVariable(M, Int8PtrTy, false,
GlobalValue::ExternalWeakLinkage, nullptr,
SymbolName);
OutStreamer->emitSymbolAttribute(getSymbol(Global), MCSA_WeakReference);
}
}
}
// Print aliases in topological order, that is, for each alias a = b,
// b must be printed before a.
// This is because on some targets (e.g. PowerPC) linker expects aliases in
// such an order to generate correct TOC information.
SmallVector<const GlobalAlias *, 16> AliasStack;
SmallPtrSet<const GlobalAlias *, 16> AliasVisited;
for (const auto &Alias : M.aliases()) {
if (Alias.hasAvailableExternallyLinkage())
continue;
for (const GlobalAlias *Cur = &Alias; Cur;
Cur = dyn_cast<GlobalAlias>(Cur->getAliasee())) {
if (!AliasVisited.insert(Cur).second)
break;
AliasStack.push_back(Cur);
}
for (const GlobalAlias *AncestorAlias : llvm::reverse(AliasStack))
emitGlobalAlias(M, *AncestorAlias);
AliasStack.clear();
}
for (const auto &IFunc : M.ifuncs())
emitGlobalIFunc(M, IFunc);
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 bytes for llvm.commandline metadata.
// The command line metadata is emitted earlier on XCOFF.
if (!TM.getTargetTriple().isOSBinFormatXCOFF())
emitModuleCommandLines(M);
// Emit .note.GNU-split-stack and .note.GNU-no-split-stack sections if
// split-stack is used.
if (TM.getTargetTriple().isOSBinFormatELF() && HasSplitStack) {
OutStreamer->switchSection(OutContext.getELFSection(".note.GNU-split-stack",
ELF::SHT_PROGBITS, 0));
if (HasNoSplitStack)
OutStreamer->switchSection(OutContext.getELFSection(
".note.GNU-no-split-stack", ELF::SHT_PROGBITS, 0));
}
// 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 (MCSection *S = MAI->getNonexecutableStackSection(OutContext))
OutStreamer->switchSection(S);
if (TM.Options.EmitAddrsig) {
// Emit address-significance attributes for all globals.
OutStreamer->emitAddrsig();
for (const GlobalValue &GV : M.global_values()) {
if (!GV.use_empty() && !GV.isThreadLocal() &&
!GV.hasDLLImportStorageClass() && !GV.getName().startswith("llvm.") &&
!GV.hasAtLeastLocalUnnamedAddr())
OutStreamer->emitAddrsigSym(getSymbol(&GV));
}
}
// Emit symbol partition specifications (ELF only).
if (TM.getTargetTriple().isOSBinFormatELF()) {
unsigned UniqueID = 0;
for (const GlobalValue &GV : M.global_values()) {
if (!GV.hasPartition() || GV.isDeclarationForLinker() ||
GV.getVisibility() != GlobalValue::DefaultVisibility)
continue;
OutStreamer->switchSection(
OutContext.getELFSection(".llvm_sympart", ELF::SHT_LLVM_SYMPART, 0, 0,
"", false, ++UniqueID, nullptr));
OutStreamer->emitBytes(GV.getPartition());
OutStreamer->emitZeros(1);
OutStreamer->emitValue(
MCSymbolRefExpr::create(getSymbol(&GV), OutContext),
MAI->getCodePointerSize());
}
}
// Allow the target to emit any magic that it wants at the end of the file,
// after everything else has gone out.
emitEndOfAsmFile(M);
MMI = nullptr;
AddrLabelSymbols = nullptr;
OutStreamer->finish();
OutStreamer->reset();
OwnedMLI.reset();
OwnedMDT.reset();
return false;
}
MCSymbol *AsmPrinter::getMBBExceptionSym(const MachineBasicBlock &MBB) {
auto Res = MBBSectionExceptionSyms.try_emplace(MBB.getSectionIDNum());
if (Res.second)
Res.first->second = createTempSymbol("exception");
return Res.first->second;
}
void AsmPrinter::SetupMachineFunction(MachineFunction &MF) {
this->MF = &MF;
const Function &F = MF.getFunction();
// Record that there are split-stack functions, so we will emit a special
// section to tell the linker.
if (MF.shouldSplitStack()) {
HasSplitStack = true;
if (!MF.getFrameInfo().needsSplitStackProlog())
HasNoSplitStack = true;
} else
HasNoSplitStack = true;
// Get the function symbol.
if (!MAI->needsFunctionDescriptors()) {
CurrentFnSym = getSymbol(&MF.getFunction());
} else {
assert(TM.getTargetTriple().isOSAIX() &&
"Only AIX uses the function descriptor hooks.");
// AIX is unique here in that the name of the symbol emitted for the
// function body does not have the same name as the source function's
// C-linkage name.
assert(CurrentFnDescSym && "The function descriptor symbol needs to be"
" initalized first.");
// Get the function entry point symbol.
CurrentFnSym = getObjFileLowering().getFunctionEntryPointSymbol(&F, TM);
}
CurrentFnSymForSize = CurrentFnSym;
CurrentFnBegin = nullptr;
CurrentFnBeginLocal = nullptr;
CurrentSectionBeginSym = nullptr;
MBBSectionRanges.clear();
MBBSectionExceptionSyms.clear();
bool NeedsLocalForSize = MAI->needsLocalForSize();
if (F.hasFnAttribute("patchable-function-entry") ||
F.hasFnAttribute("function-instrument") ||
F.hasFnAttribute("xray-instruction-threshold") ||
needFuncLabels(MF) || NeedsLocalForSize ||
MF.getTarget().Options.EmitStackSizeSection || MF.hasBBLabels()) {
CurrentFnBegin = createTempSymbol("func_begin");
if (NeedsLocalForSize)
CurrentFnSymForSize = CurrentFnBegin;
}
ORE = &getAnalysis<MachineOptimizationRemarkEmitterPass>().getORE();
}
namespace {
// Keep track the alignment, constpool entries per Section.
struct SectionCPs {
MCSection *S;
Align Alignment;
SmallVector<unsigned, 4> CPEs;
SectionCPs(MCSection *s, Align a) : S(s), Alignment(a) {}
};
} // end anonymous namespace
/// 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];
Align Alignment = CPE.getAlign();
SectionKind Kind = CPE.getSectionKind(&getDataLayout());
const Constant *C = nullptr;
if (!CPE.isMachineConstantPoolEntry())
C = CPE.Val.ConstVal;
MCSection *S = getObjFileLowering().getSectionForConstant(
getDataLayout(), Kind, C, Alignment);
// 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, Alignment));
}
if (Alignment > CPSections[SecIdx].Alignment)
CPSections[SecIdx].Alignment = Alignment;
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(Align(CPSections[i].Alignment));
CurSection = CPSections[i].S;
Offset = 0;
}
MachineConstantPoolEntry CPE = CP[CPI];
// Emit inter-object padding for alignment.
unsigned NewOffset = alignTo(Offset, CPE.getAlign());
OutStreamer->emitZeros(NewOffset - Offset);
Offset = NewOffset + CPE.getSizeInBytes(getDataLayout());
OutStreamer->emitLabel(Sym);
if (CPE.isMachineConstantPoolEntry())
emitMachineConstantPoolValue(CPE.Val.MachineCPVal);
else
emitGlobalConstant(getDataLayout(), CPE.Val.ConstVal);
}
}
}
// Print assembly representations of the jump tables used by the current
// function.
void AsmPrinter::emitJumpTableInfo() {
const DataLayout &DL = MF->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 ||
MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference64,
F);
if (JTInDiffSection) {
// Drop it in the readonly section.
MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(F, TM);
OutStreamer->switchSection(ReadOnlySection);
}
emitAlignment(Align(MJTI->getEntryAlignment(DL)));
// 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->doesSetDirectiveSuppressReloc()) {
SmallPtrSet<const MachineBasicBlock*, 16> EmittedSets;
const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
const MCExpr *Base = TLI->getPICJumpTableRelocBaseExpr(MF,JTI,OutContext);
for (const MachineBasicBlock *MBB : JTBBs) {
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 local label started with 'l' would work. Simplify
// GetJTISymbol.
OutStreamer->emitLabel(GetJTISymbol(JTI, true));
MCSymbol* JTISymbol = GetJTISymbol(JTI);
OutStreamer->emitLabel(JTISymbol);
for (const MachineBasicBlock *MBB : JTBBs)
emitJumpTableEntry(MJTI, MBB, 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:
case MachineJumpTableInfo::EK_LabelDifference64: {
// 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 (MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 &&
MAI->doesSetDirectiveSuppressReloc()) {
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(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 (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->getParent()->getDataLayout(), GV->getInitializer(),
/* isCtor */ true);
return true;
}
if (GV->getName() == "llvm.global_dtors") {
emitXXStructorList(GV->getParent()->getDataLayout(), GV->getInitializer(),
/* isCtor */ false);
return true;
}
report_fatal_error("unknown special variable");
}
/// EmitLLVMUsedList - For targets that define a MAI::UsedDirective, mark each
/// global in the specified llvm.used list.
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);