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Diffstat (limited to 'contrib/llvm-project/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp')
| -rw-r--r-- | contrib/llvm-project/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp | 3210 |
1 files changed, 3210 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/contrib/llvm-project/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp new file mode 100644 index 000000000000..54f6cc2d5571 --- /dev/null +++ b/contrib/llvm-project/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp @@ -0,0 +1,3210 @@ +//===- 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 "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/StringRef.h" +#include "llvm/ADT/Triple.h" +#include "llvm/ADT/Twine.h" +#include "llvm/Analysis/ConstantFolding.h" +#include "llvm/Analysis/EHPersonalities.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/GCStrategy.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/MachineMemOperand.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/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/Function.h" +#include "llvm/IR/GlobalAlias.h" +#include "llvm/IR/GlobalIFunc.h" +#include "llvm/IR/GlobalIndirectSymbol.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/RemarkStreamer.h" +#include "llvm/IR/Type.h" +#include "llvm/IR/Value.h" +#include "llvm/MC/MCAsmInfo.h" +#include "llvm/MC/MCCodePadder.h" +#include "llvm/MC/MCContext.h" +#include "llvm/MC/MCDirectives.h" +#include "llvm/MC/MCDwarf.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/Pass.h" +#include "llvm/Remarks/Remark.h" +#include "llvm/Remarks/RemarkFormat.h" +#include "llvm/Remarks/RemarkStringTable.h" +#include "llvm/Support/Casting.h" +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Compiler.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/Format.h" +#include "llvm/Support/MathExtras.h" +#include "llvm/Support/Path.h" +#include "llvm/Support/TargetRegistry.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 <algorithm> +#include <cassert> +#include <cinttypes> +#include <cstdint> +#include <iterator> +#include <limits> +#include <memory> +#include <string> +#include <utility> +#include <vector> + +using namespace llvm; + +#define DEBUG_TYPE "asm-printer" + +static const char *const DWARFGroupName = "dwarf"; +static const char *const DWARFGroupDescription = "DWARF Emission"; +static const char *const DbgTimerName = "emit"; +static const char *const DbgTimerDescription = "Debug Info Emission"; +static const char *const EHTimerName = "write_exception"; +static const char *const EHTimerDescription = "DWARF Exception Writer"; +static const char *const CFGuardName = "Control Flow Guard"; +static const char *const CFGuardDescription = "Control Flow Guard Tables"; +static const char *const CodeViewLineTablesGroupName = "linetables"; +static const char *const CodeViewLineTablesGroupDescription = + "CodeView Line Tables"; + +STATISTIC(EmittedInsts, "Number of machine instrs printed"); + +static cl::opt<bool> EnableRemarksSection( + "remarks-section", + cl::desc("Emit a section containing remark diagnostics metadata"), + cl::init(false)); + +char AsmPrinter::ID = 0; + +using gcp_map_type = DenseMap<GCStrategy *, std::unique_ptr<GCMetadataPrinter>>; + +static gcp_map_type &getGCMap(void *&P) { + if (!P) + P = new gcp_map_type(); + return *(gcp_map_type*)P; +} + +/// getGVAlignmentLog2 - Return the alignment to use for the specified global +/// value in log2 form. This rounds up to the preferred alignment if possible +/// and legal. +static unsigned getGVAlignmentLog2(const GlobalValue *GV, const DataLayout &DL, + unsigned InBits = 0) { + unsigned NumBits = 0; + if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) + NumBits = DL.getPreferredAlignmentLog(GVar); + + // If InBits is specified, round it to it. + if (InBits > NumBits) + NumBits = InBits; + + // If the GV has a specified alignment, take it into account. + if (GV->getAlignment() == 0) + return NumBits; + + unsigned GVAlign = Log2_32(GV->getAlignment()); + + // If the GVAlign is larger than NumBits, or if we are required to obey + // NumBits because the GV has an assigned section, obey it. + if (GVAlign > NumBits || GV->hasSection()) + NumBits = GVAlign; + return NumBits; +} + +AsmPrinter::AsmPrinter(TargetMachine &tm, std::unique_ptr<MCStreamer> Streamer) + : MachineFunctionPass(ID), TM(tm), MAI(tm.getMCAsmInfo()), + OutContext(Streamer->getContext()), OutStreamer(std::move(Streamer)) { + VerboseAsm = OutStreamer->isVerboseAsm(); +} + +AsmPrinter::~AsmPrinter() { + assert(!DD && Handlers.empty() && "Debug/EH info didn't get finalized"); + + if (GCMetadataPrinters) { + gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); + + delete &GCMap; + GCMetadataPrinters = nullptr; + } +} + +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 { + 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) { + assert(DD && "Dwarf debug file is not defined."); + assert(OutStreamer->hasRawTextSupport() && "Expected assembly output mode."); + (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<MachineModuleInfo>(); + AU.addRequired<MachineOptimizationRemarkEmitterPass>(); + AU.addRequired<GCModuleInfo>(); +} + +bool AsmPrinter::doInitialization(Module &M) { + MMI = getAnalysisIfAvailable<MachineModuleInfo>(); + + // Initialize TargetLoweringObjectFile. + const_cast<TargetLoweringObjectFile&>(getObjFileLowering()) + .Initialize(OutContext, TM); + + const_cast<TargetLoweringObjectFile &>(getObjFileLowering()) + .getModuleMetadata(M); + + OutStreamer->InitSections(false); + + // 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(); + OutStreamer->EmitVersionForTarget(Target, M.getSDKVersion()); + + // Allow the target to emit any magic that it wants at the start of the file. + EmitStartOfAsmFile(M); + + // Very minimal debug info. It is ignored if we emit actual debug info. If we + // don't, this at least helps the user find where a global came from. + if (MAI->hasSingleParameterDotFile()) { + // .file "foo.c" + OutStreamer->EmitFileDirective( + llvm::sys::path::filename(M.getSourceFileName())); + } + + GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); + assert(MI && "AsmPrinter didn't require GCModuleInfo?"); + for (auto &I : *MI) + if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I)) + MP->beginAssembly(M, *MI, *this); + + // Emit module-level inline asm if it exists. + if (!M.getModuleInlineAsm().empty()) { + // We're at the module level. Construct MCSubtarget from the default CPU + // and target triple. + std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo( + TM.getTargetTriple().str(), TM.getTargetCPU(), + TM.getTargetFeatureString())); + OutStreamer->AddComment("Start of file scope inline assembly"); + OutStreamer->AddBlankLine(); + EmitInlineAsm(M.getModuleInlineAsm()+"\n", + OutContext.getSubtargetCopy(*STI), TM.Options.MCOptions); + OutStreamer->AddComment("End of file scope inline assembly"); + OutStreamer->AddBlankLine(); + } + + if (MAI->doesSupportDebugInformation()) { + bool EmitCodeView = MMI->getModule()->getCodeViewFlag(); + if (EmitCodeView && TM.getTargetTriple().isOSWindows()) { + Handlers.emplace_back(llvm::make_unique<CodeViewDebug>(this), + DbgTimerName, DbgTimerDescription, + CodeViewLineTablesGroupName, + CodeViewLineTablesGroupDescription); + } + if (!EmitCodeView || MMI->getModule()->getDwarfVersion()) { + DD = new DwarfDebug(this, &M); + DD->beginModule(); + Handlers.emplace_back(std::unique_ptr<DwarfDebug>(DD), DbgTimerName, + DbgTimerDescription, DWARFGroupName, + DWARFGroupDescription); + } + } + + switch (MAI->getExceptionHandlingType()) { + case ExceptionHandling::SjLj: + case ExceptionHandling::DwarfCFI: + case ExceptionHandling::ARM: + isCFIMoveForDebugging = true; + if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI) + break; + for (auto &F: M.getFunctionList()) { + // If the module contains any function with unwind data, + // .eh_frame has to be emitted. + // Ignore functions that won't get emitted. + if (!F.isDeclarationForLinker() && F.needsUnwindTableEntry()) { + isCFIMoveForDebugging = false; + break; + } + } + break; + default: + isCFIMoveForDebugging = false; + break; + } + + EHStreamer *ES = nullptr; + switch (MAI->getExceptionHandlingType()) { + case ExceptionHandling::None: + break; + case ExceptionHandling::SjLj: + case ExceptionHandling::DwarfCFI: + ES = new DwarfCFIException(this); + break; + case ExceptionHandling::ARM: + ES = new ARMException(this); + break; + case ExceptionHandling::WinEH: + switch (MAI->getWinEHEncodingType()) { + default: llvm_unreachable("unsupported unwinding information encoding"); + case WinEH::EncodingType::Invalid: + break; + case WinEH::EncodingType::X86: + case WinEH::EncodingType::Itanium: + ES = new WinException(this); + break; + } + break; + case ExceptionHandling::Wasm: + ES = new WasmException(this); + break; + } + if (ES) + Handlers.emplace_back(std::unique_ptr<EHStreamer>(ES), EHTimerName, + EHTimerDescription, DWARFGroupName, + DWARFGroupDescription); + + if (mdconst::extract_or_null<ConstantInt>( + MMI->getModule()->getModuleFlag("cfguardtable"))) + Handlers.emplace_back(llvm::make_unique<WinCFGuard>(this), CFGuardName, + CFGuardDescription, DWARFGroupName, + DWARFGroupDescription); + + 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->hasLinkOnceDirective()) { + // .globl _foo + OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global); + //NOTE: linkonce is handled by the section the symbol was assigned to. + } else { + // .weak _foo + OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Weak); + } + return; + case GlobalValue::ExternalLinkage: + // If external, declare as a global symbol: .globl _foo + OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Global); + return; + case GlobalValue::PrivateLinkage: + case GlobalValue::InternalLinkage: + return; + case GlobalValue::AppendingLinkage: + case GlobalValue::AvailableExternallyLinkage: + case GlobalValue::ExternalWeakLinkage: + 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); +} + +/// 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->hasInitializer()) // External globals require no extra code. + return; + + GVSym->redefineIfPossible(); + if (GVSym->isDefined() || GVSym->isVariable()) + report_fatal_error("symbol '" + Twine(GVSym->getName()) + + "' is already defined"); + + if (MAI->hasDotTypeDotSizeDirective()) + OutStreamer->EmitSymbolAttribute(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). + unsigned AlignLog = getGVAlignmentLog2(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. + unsigned Align = 1 << AlignLog; + if (!getObjFileLowering().getCommDirectiveSupportsAlignment()) + Align = 0; + + // .comm _foo, 42, 4 + OutStreamer->EmitCommonSymbol(GVSym, Size, Align); + 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. + unsigned Align = 1 << AlignLog; + EmitLinkage(GV, GVSym); + // .zerofill __DATA, __bss, _foo, 400, 5 + OutStreamer->EmitZerofill(TheSection, GVSym, Size, Align); + 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. + unsigned Align = 1 << AlignLog; + + // Use .lcomm only if it supports user-specified alignment. + // Otherwise, while it would still be correct to use .lcomm in some + // cases (e.g. when Align == 1), the external assembler might enfore + // some -unknown- default alignment behavior, which could cause + // spurious differences between external and integrated assembler. + // Prefer to simply fall back to .local / .comm in this case. + if (MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) { + // .lcomm _foo, 42 + OutStreamer->EmitLocalCommonSymbol(GVSym, Size, Align); + return; + } + + if (!getObjFileLowering().getCommDirectiveSupportsAlignment()) + Align = 0; + + // .local _foo + OutStreamer->EmitSymbolAttribute(GVSym, MCSA_Local); + // .comm _foo, 42, 4 + OutStreamer->EmitCommonSymbol(GVSym, Size, Align); + return; + } + + // Handle thread local data for mach-o which requires us to output an + // additional structure of data and mangle the original symbol so that we + // can reference it later. + // + // TODO: This should become an "emit thread local global" method on TLOF. + // All of this macho specific stuff should be sunk down into TLOFMachO and + // stuff like "TLSExtraDataSection" should no longer be part of the parent + // TLOF class. This will also make it more obvious that stuff like + // MCStreamer::EmitTBSSSymbol is macho specific and only called from macho + // specific code. + if (GVKind.isThreadLocal() && MAI->hasMachoTBSSDirective()) { + // Emit the .tbss symbol + MCSymbol *MangSym = + OutContext.getOrCreateSymbol(GVSym->getName() + Twine("$tlv$init")); + + if (GVKind.isThreadBSS()) { + TheSection = getObjFileLowering().getTLSBSSSection(); + OutStreamer->EmitTBSSSymbol(TheSection, MangSym, Size, 1 << AlignLog); + } else if (GVKind.isThreadData()) { + OutStreamer->SwitchSection(TheSection); + + EmitAlignment(AlignLog, GV); + OutStreamer->EmitLabel(MangSym); + + EmitGlobalConstant(GV->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(AlignLog, GV); + + OutStreamer->EmitLabel(EmittedInitSym); + + 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); +} + +/// 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. + OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(&F, TM)); + EmitVisibility(CurrentFnSym, F.getVisibility()); + + 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); + + if (isVerbose()) { + F.printAsOperand(OutStreamer->GetCommentOS(), + /*PrintType=*/false, F.getParent()); + OutStreamer->GetCommentOS() << '\n'; + } + + // 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 the CurrentFnSym. This is a virtual function to allow targets to + // do their wild and crazy things as required. + EmitFunctionEntryLabel(); + + // If the function had address-taken blocks that got deleted, then we have + // references to the dangling symbols. Emit them at the start of the function + // so that we don't get references to undefined symbols. + std::vector<MCSymbol*> DeadBlockSyms; + MMI->takeDeletedSymbolsForFunction(&F, DeadBlockSyms); + for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) { + OutStreamer->AddComment("Address taken block that was later removed"); + OutStreamer->EmitLabel(DeadBlockSyms[i]); + } + + if (CurrentFnBegin) { + if (MAI->useAssignmentForEHBegin()) { + MCSymbol *CurPos = OutContext.createTempSymbol(); + OutStreamer->EmitLabel(CurPos); + OutStreamer->EmitAssignment(CurrentFnBegin, + MCSymbolRefExpr::create(CurPos, OutContext)); + } else { + OutStreamer->EmitLabel(CurrentFnBegin); + } + } + + // Emit pre-function debug and/or EH information. + for (const HandlerInfo &HI : Handlers) { + NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, + HI.TimerGroupDescription, TimePassesIsEnabled); + HI.Handler->beginFunction(MF); + } + + // 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"); + if (CurrentFnSym->isDefined()) + report_fatal_error("'" + Twine(CurrentFnSym->getName()) + + "' label emitted multiple times to assembly file"); + + return OutStreamer->EmitLabel(CurrentFnSym); +} + +/// emitComments - Pretty-print comments for instructions. +static void emitComments(const MachineInstr &MI, raw_ostream &CommentOS) { + const MachineFunction *MF = MI.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. + Optional<unsigned> Size; + if ((Size = MI.getRestoreSize(TII))) { + CommentOS << *Size << "-byte Reload\n"; + } else if ((Size = MI.getFoldedRestoreSize(TII))) { + if (*Size) + 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) + 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 { + unsigned 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 (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { + const MachineOperand &Op = MI->getOperand(i); + assert(Op.isReg() && "KILL instruction must have only register operands"); + 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->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 << " <- "; + + // The second operand is only an offset if it's an immediate. + bool MemLoc = MI->getOperand(0).isReg() && MI->getOperand(1).isImm(); + int64_t Offset = MemLoc ? MI->getOperand(1).getImm() : 0; + const DIExpression *Expr = MI->getDebugExpression(); + if (Expr->getNumElements()) { + OS << '['; + bool NeedSep = false; + for (auto Op : Expr->expr_ops()) { + if (NeedSep) + OS << ", "; + else + NeedSep = true; + OS << 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. + if (MI->getOperand(0).isFPImm()) { + APFloat APF = APFloat(MI->getOperand(0).getFPImm()->getValueAPF()); + if (MI->getOperand(0).getFPImm()->getType()->isFloatTy()) { + OS << (double)APF.convertToFloat(); + } else if (MI->getOperand(0).getFPImm()->getType()->isDoubleTy()) { + OS << APF.convertToDouble(); + } else { + // There is no good way to print long double. Convert a copy to + // double. Ah well, it's only a comment. + bool ignored; + APF.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven, + &ignored); + OS << "(long double) " << APF.convertToDouble(); + } + } else if (MI->getOperand(0).isImm()) { + OS << MI->getOperand(0).getImm(); + } else if (MI->getOperand(0).isCImm()) { + MI->getOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/); + } else { + unsigned Reg; + if (MI->getOperand(0).isReg()) { + Reg = MI->getOperand(0).getReg(); + } else { + assert(MI->getOperand(0).isFI() && "Unknown operand type"); + const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering(); + Offset += TFI->getFrameIndexReference(*AP.MF, + MI->getOperand(0).getIndex(), Reg); + MemLoc = true; + } + if (Reg == 0) { + // Suppress offset, it is not meaningful here. + OS << "undef"; + // NOTE: Want this comment at start of line, don't emit with AddComment. + AP.OutStreamer->emitRawComment(OS.str()); + return true; + } + if (MemLoc) + OS << '['; + OS << printReg(Reg, AP.MF->getSubtarget().getRegisterInfo()); + } + + if (MemLoc) + OS << '+' << Offset << ']'; + + // 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())) { + 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::CFIMoveType AsmPrinter::needsCFIMoves() const { + if (MAI->getExceptionHandlingType() == ExceptionHandling::DwarfCFI && + MF->getFunction().needsUnwindTableEntry()) + return CFI_M_EH; + + if (MMI->hasDebugInfo()) + return CFI_M_Debug; + + return CFI_M_None; +} + +bool AsmPrinter::needsSEHMoves() { + return MAI->usesWindowsCFI() && MF->getFunction().needsUnwindTableEntry(); +} + +void AsmPrinter::emitCFIInstruction(const MachineInstr &MI) { + ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType(); + if (ExceptionHandlingType != ExceptionHandling::DwarfCFI && + ExceptionHandlingType != ExceptionHandling::ARM) + return; + + if (needsCFIMoves() == CFI_M_None) + return; + + // 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)); +} + +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(); + OutStreamer->EmitSymbolValue(FunctionSymbol, TM.getProgramPointerSize()); + OutStreamer->EmitULEB128IntValue(StackSize); + + OutStreamer->PopSection(); +} + +static bool needFuncLabelsForEHOrDebugInfo(const MachineFunction &MF, + MachineModuleInfo *MMI) { + if (!MF.getLandingPads().empty() || MF.hasEHFunclets() || MMI->hasDebugInfo()) + 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(); + + bool ShouldPrintDebugScopes = MMI->hasDebugInfo(); + + if (isVerbose()) { + // Get MachineDominatorTree or compute it on the fly if it's unavailable + MDT = getAnalysisIfAvailable<MachineDominatorTree>(); + if (!MDT) { + OwnedMDT = 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 = make_unique<MachineLoopInfo>(); + OwnedMLI->getBase().analyze(MDT->getBase()); + MLI = OwnedMLI.get(); + } + } + + // Print out code for the function. + bool HasAnyRealCode = false; + int NumInstsInFunction = 0; + for (auto &MBB : *MF) { + // Print a label for the basic block. + EmitBasicBlockStart(MBB); + for (auto &MI : MBB) { + // Print the assembly for the instruction. + if (!MI.isPosition() && !MI.isImplicitDef() && !MI.isKill() && + !MI.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 (ShouldPrintDebugScopes) { + 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::EH_LABEL: + case TargetOpcode::GC_LABEL: + OutStreamer->EmitLabel(MI.getOperand(0).getMCSymbol()); + break; + case TargetOpcode::INLINEASM: + case TargetOpcode::INLINEASM_BR: + EmitInlineAsm(&MI); + break; + case TargetOpcode::DBG_VALUE: + if (isVerbose()) { + if (!emitDebugValueComment(&MI, *this)) + EmitInstruction(&MI); + } + 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; + default: + EmitInstruction(&MI); + break; + } + + // If there is a post-instruction symbol, emit a label for it here. + if (MCSymbol *S = MI.getPostInstrSymbol()) + OutStreamer->EmitLabel(S); + + if (ShouldPrintDebugScopes) { + for (const HandlerInfo &HI : Handlers) { + NamedRegionTimer T(HI.TimerName, HI.TimerDescription, + HI.TimerGroupName, HI.TimerGroupDescription, + TimePassesIsEnabled); + HI.Handler->endInstruction(); + } + } + } + + EmitBasicBlockEnd(MBB); + } + + 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()->getNoop(Noop); + + // Targets can opt-out of emitting the noop here by leaving the opcode + // unspecified. + if (Noop.getOpcode()) { + OutStreamer->AddComment("avoids zero-length function"); + OutStreamer->EmitInstruction(Noop, getSubtargetInfo()); + } + } + + const Function &F = MF->getFunction(); + for (const auto &BB : F) { + if (!BB.hasAddressTaken()) + continue; + MCSymbol *Sym = GetBlockAddressSymbol(&BB); + if (Sym->isDefined()) + continue; + OutStreamer->AddComment("Address of block that was removed by CodeGen"); + OutStreamer->EmitLabel(Sym); + } + + // Emit target-specific gunk after the function body. + EmitFunctionBodyEnd(); + + if (needFuncLabelsForEHOrDebugInfo(*MF, MMI) || + MAI->hasDotTypeDotSizeDirective()) { + // 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 (MAI->hasDotTypeDotSizeDirective()) { + // We can get the size as difference between the function label and the + // temp label. + const MCExpr *SizeExp = MCBinaryExpr::createSub( + MCSymbolRefExpr::create(CurrentFnEnd, OutContext), + MCSymbolRefExpr::create(CurrentFnSymForSize, OutContext), OutContext); + OutStreamer->emitELFSize(CurrentFnSym, SizeExp); + } + + for (const HandlerInfo &HI : Handlers) { + NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, + HI.TimerGroupDescription, TimePassesIsEnabled); + HI.Handler->markFunctionEnd(); + } + + // Print out jump tables referenced by the function. + EmitJumpTableInfo(); + + // Emit post-function debug and/or EH information. + for (const HandlerInfo &HI : Handlers) { + NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, + HI.TimerGroupDescription, TimePassesIsEnabled); + HI.Handler->endFunction(MF); + } + + // Emit section containing stack size metadata. + emitStackSizeSection(*MF); + + if (isVerbose()) + OutStreamer->GetCommentOS() << "-- End function\n"; + + OutStreamer->AddBlankLine(); +} + +/// Compute the number of Global Variables that uses a Constant. +static unsigned getNumGlobalVariableUses(const Constant *C) { + if (!C) + return 0; + + if (isa<GlobalVariable>(C)) + return 1; + + unsigned NumUses = 0; + for (auto *CU : C->users()) + NumUses += getNumGlobalVariableUses(dyn_cast<Constant>(CU)); + + return NumUses; +} + +/// 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 (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 (auto *GV : FailedCandidates) + EmitGlobalVariable(GV); +} + +void AsmPrinter::emitGlobalIndirectSymbol(Module &M, + const GlobalIndirectSymbol& GIS) { + MCSymbol *Name = getSymbol(&GIS); + + if (GIS.hasExternalLinkage() || !MAI->getWeakRefDirective()) + OutStreamer->EmitSymbolAttribute(Name, MCSA_Global); + else if (GIS.hasWeakLinkage() || GIS.hasLinkOnceLinkage()) + OutStreamer->EmitSymbolAttribute(Name, MCSA_WeakReference); + else + assert(GIS.hasLocalLinkage() && "Invalid alias or ifunc linkage"); + + bool IsFunction = GIS.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) + if (auto *CE = dyn_cast<ConstantExpr>(GIS.getIndirectSymbol())) + if (CE->getOpcode() == Instruction::BitCast) + IsFunction = + CE->getOperand(0)->getType()->getPointerElementType()->isFunctionTy(); + + // 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 (isa<GlobalIFunc>(GIS)) + OutStreamer->EmitSymbolAttribute(Name, MCSA_ELF_TypeIndFunction); + } + + EmitVisibility(Name, GIS.getVisibility()); + + const MCExpr *Expr = lowerConstant(GIS.getIndirectSymbol()); + + if (isa<GlobalAlias>(&GIS) && MAI->hasAltEntry() && isa<MCBinaryExpr>(Expr)) + OutStreamer->EmitSymbolAttribute(Name, MCSA_AltEntry); + + // Emit the directives as assignments aka .set: + OutStreamer->EmitAssignment(Name, Expr); + + if (auto *GA = dyn_cast<GlobalAlias>(&GIS)) { + // 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->getBaseObject(); + 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::emitRemarksSection(Module &M) { + RemarkStreamer *RS = M.getContext().getRemarkStreamer(); + if (!RS) + return; + const remarks::Serializer &Serializer = RS->getSerializer(); + + // Switch to the right section: .remarks/__remarks. + MCSection *RemarksSection = + OutContext.getObjectFileInfo()->getRemarksSection(); + OutStreamer->SwitchSection(RemarksSection); + + // Emit the magic number. + OutStreamer->EmitBytes(remarks::Magic); + // Explicitly emit a '\0'. + OutStreamer->EmitIntValue(/*Value=*/0, /*Size=*/1); + + // Emit the version number: little-endian uint64_t. + // The version number is located at the offset 0x0 in the section. + std::array<char, 8> Version; + support::endian::write64le(Version.data(), remarks::Version); + OutStreamer->EmitBinaryData(StringRef(Version.data(), Version.size())); + + // Emit the string table in the section. + // Note: we need to use the streamer here to emit it in the section. We can't + // just use the serialize function with a raw_ostream because of the way + // MCStreamers work. + uint64_t StrTabSize = + Serializer.StrTab ? Serializer.StrTab->SerializedSize : 0; + // Emit the total size of the string table (the size itself excluded): + // little-endian uint64_t. + // The total size is located after the version number. + // Note: even if no string table is used, emit 0. + std::array<char, 8> StrTabSizeBuf; + support::endian::write64le(StrTabSizeBuf.data(), StrTabSize); + OutStreamer->EmitBinaryData( + StringRef(StrTabSizeBuf.data(), StrTabSizeBuf.size())); + + if (const Optional<remarks::StringTable> &StrTab = Serializer.StrTab) { + std::vector<StringRef> StrTabStrings = StrTab->serialize(); + // Emit a list of null-terminated strings. + // Note: the order is important here: the ID used in the remarks corresponds + // to the position of the string in the section. + for (StringRef Str : StrTabStrings) { + OutStreamer->EmitBytes(Str); + // Explicitly emit a '\0'. + OutStreamer->EmitIntValue(/*Value=*/0, /*Size=*/1); + } + } + + // Emit the null-terminated absolute path to the remark file. + // The path is located at the offset 0x4 in the section. + StringRef FilenameRef = RS->getFilename(); + SmallString<128> Filename = FilenameRef; + sys::fs::make_absolute(Filename); + assert(!Filename.empty() && "The filename can't be empty."); + OutStreamer->EmitBytes(Filename); + // Explicitly emit a '\0'. + OutStreamer->EmitIntValue(/*Value=*/0, /*Size=*/1); +} + +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(); + + // Emit visibility info for declarations + for (const Function &F : M) { + if (!F.isDeclarationForLinker()) + continue; + GlobalValue::VisibilityTypes V = F.getVisibility(); + if (V == GlobalValue::DefaultVisibility) + continue; + + MCSymbol *Name = getSymbol(&F); + EmitVisibility(Name, V, false); + } + + // 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 (EnableRemarksSection) + emitRemarksSection(M); + + const TargetLoweringObjectFile &TLOF = getObjFileLowering(); + + 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(Log2_32(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(Log2_32(DL.getPointerSize())); + OutStreamer->EmitSymbolAttribute(Stub.first, MCSA_Global); + OutStreamer->EmitLabel(Stub.first); + OutStreamer->EmitSymbolValue(Stub.second.getPointer(), + DL.getPointerSize()); + } + } + } + + // Finalize debug and EH information. + for (const HandlerInfo &HI : Handlers) { + NamedRegionTimer T(HI.TimerName, HI.TimerDescription, HI.TimerGroupName, + HI.TimerGroupDescription, TimePassesIsEnabled); + HI.Handler->endModule(); + } + Handlers.clear(); + DD = nullptr; + + // If the target wants to know about weak references, print them all. + if (MAI->getWeakRefDirective()) { + // FIXME: This is not lazy, it would be nice to only print weak references + // to stuff that is actually used. Note that doing so would require targets + // to notice uses in operands (due to constant exprs etc). This should + // happen with the MC stuff eventually. + + // Print out module-level global objects here. + for (const auto &GO : M.global_objects()) { + if (!GO.hasExternalWeakLinkage()) + continue; + OutStreamer->EmitSymbolAttribute(getSymbol(&GO), MCSA_WeakReference); + } + } + + OutStreamer->AddBlankLine(); + + // 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()) { + 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)) + emitGlobalIndirectSymbol(M, *AncestorAlias); + AliasStack.clear(); + } + for (const auto &IFunc : M.ifuncs()) + emitGlobalIndirectSymbol(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. + EmitModuleCommandLines(M); + + // Emit __morestack address if needed for indirect calls. + if (MMI->usesMorestackAddr()) { + unsigned Align = 1; + MCSection *ReadOnlySection = getObjFileLowering().getSectionForConstant( + getDataLayout(), SectionKind::getReadOnly(), + /*C=*/nullptr, Align); + OutStreamer->SwitchSection(ReadOnlySection); + + MCSymbol *AddrSymbol = + OutContext.getOrCreateSymbol(StringRef("__morestack_addr")); + OutStreamer->EmitLabel(AddrSymbol); + + unsigned PtrSize = MAI->getCodePointerSize(); + OutStreamer->EmitSymbolValue(GetExternalSymbolSymbol("__morestack"), + PtrSize); + } + + // Emit .note.GNU-split-stack and .note.GNU-no-split-stack sections if + // split-stack is used. + if (TM.getTargetTriple().isOSBinFormatELF() && MMI->hasSplitStack()) { + OutStreamer->SwitchSection( + OutContext.getELFSection(".note.GNU-split-stack", ELF::SHT_PROGBITS, 0)); + if (MMI->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.getTargetTriple().isOSBinFormatCOFF()) { + // Emit /EXPORT: flags for each exported global as necessary. + const auto &TLOF = getObjFileLowering(); + std::string Flags; + + for (const GlobalValue &GV : M.global_values()) { + raw_string_ostream OS(Flags); + TLOF.emitLinkerFlagsForGlobal(OS, &GV); + OS.flush(); + if (!Flags.empty()) { + OutStreamer->SwitchSection(TLOF.getDrectveSection()); + OutStreamer->EmitBytes(Flags); + } + Flags.clear(); + } + + // Emit /INCLUDE: flags for each used global as necessary. + if (const auto *LU = M.getNamedGlobal("llvm.used")) { + assert(LU->hasInitializer() && + "expected llvm.used to have an initializer"); + assert(isa<ArrayType>(LU->getValueType()) && + "expected llvm.used to be an array type"); + if (const auto *A = cast<ConstantArray>(LU->getInitializer())) { + for (const Value *Op : A->operands()) { + const auto *GV = + cast<GlobalValue>(Op->stripPointerCastsNoFollowAliases()); + // Global symbols with internal or private linkage are not visible to + // the linker, and thus would cause an error when the linker tried to + // preserve the symbol due to the `/include:` directive. + if (GV->hasLocalLinkage()) + continue; + + raw_string_ostream OS(Flags); + TLOF.emitLinkerFlagsForUsed(OS, GV); + OS.flush(); + + if (!Flags.empty()) { + OutStreamer->SwitchSection(TLOF.getDrectveSection()); + OutStreamer->EmitBytes(Flags); + } + Flags.clear(); + } + } + } + } + + 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, "", ++UniqueID)); + 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; + + OutStreamer->Finish(); + OutStreamer->reset(); + OwnedMLI.reset(); + OwnedMDT.reset(); + + return false; +} + +MCSymbol *AsmPrinter::getCurExceptionSym() { + if (!CurExceptionSym) + CurExceptionSym = createTempSymbol("exception"); + return CurExceptionSym; +} + +void AsmPrinter::SetupMachineFunction(MachineFunction &MF) { + this->MF = &MF; + // Get the function symbol. + CurrentFnSym = getSymbol(&MF.getFunction()); + CurrentFnSymForSize = CurrentFnSym; + CurrentFnBegin = nullptr; + CurExceptionSym = nullptr; + bool NeedsLocalForSize = MAI->needsLocalForSize(); + if (needFuncLabelsForEHOrDebugInfo(MF, MMI) || NeedsLocalForSize || + MF.getTarget().Options.EmitStackSizeSection) { + 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; + unsigned Alignment; + SmallVector<unsigned, 4> CPEs; + + SectionCPs(MCSection *s, unsigned 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]; + unsigned Align = CPE.getAlignment(); + + SectionKind Kind = CPE.getSectionKind(&getDataLayout()); + + const Constant *C = nullptr; + if (!CPE.isMachineConstantPoolEntry()) + C = CPE.Val.ConstVal; + + MCSection *S = getObjFileLowering().getSectionForConstant(getDataLayout(), + Kind, C, Align); + + // The number of sections are small, just do a linear search from the + // last section to the first. + bool Found = false; + unsigned SecIdx = CPSections.size(); + while (SecIdx != 0) { + if (CPSections[--SecIdx].S == S) { + Found = true; + break; + } + } + if (!Found) { + SecIdx = CPSections.size(); + CPSections.push_back(SectionCPs(S, Align)); + } + + if (Align > CPSections[SecIdx].Alignment) + CPSections[SecIdx].Alignment = Align; + CPSections[SecIdx].CPEs.push_back(i); + } + + // Now print stuff into the calculated sections. + const MCSection *CurSection = nullptr; + unsigned Offset = 0; + for (unsigned i = 0, e = CPSections.size(); i != e; ++i) { + for (unsigned j = 0, ee = CPSections[i].CPEs.size(); j != ee; ++j) { + unsigned CPI = CPSections[i].CPEs[j]; + MCSymbol *Sym = GetCPISymbol(CPI); + if (!Sym->isUndefined()) + continue; + + if (CurSection != CPSections[i].S) { + OutStreamer->SwitchSection(CPSections[i].S); + EmitAlignment(Log2_32(CPSections[i].Alignment)); + CurSection = CPSections[i].S; + Offset = 0; + } + + MachineConstantPoolEntry CPE = CP[CPI]; + + // Emit inter-object padding for alignment. + unsigned AlignMask = CPE.getAlignment() - 1; + unsigned NewOffset = (Offset + AlignMask) & ~AlignMask; + OutStreamer->EmitZeros(NewOffset - Offset); + + Type *Ty = CPE.getType(); + Offset = NewOffset + getDataLayout().getTypeAllocSize(Ty); + + OutStreamer->EmitLabel(Sym); + if (CPE.isMachineConstantPoolEntry()) + EmitMachineConstantPoolValue(CPE.Val.MachineCPVal); + else + EmitGlobalConstant(getDataLayout(), CPE.Val.ConstVal); + } + } +} + +/// EmitJumpTableInfo - Print assembly representations of the jump tables used +/// by the current function to the current output stream. +void AsmPrinter::EmitJumpTableInfo() { + const DataLayout &DL = MF->getDataLayout(); + const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo(); + if (!MJTI) return; + if (MJTI->getEntryKind() == MachineJumpTableInfo::EK_Inline) return; + const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables(); + if (JT.empty()) return; + + // Pick the directive to use to print the jump table entries, and switch to + // the appropriate section. + const Function &F = MF->getFunction(); + const TargetLoweringObjectFile &TLOF = getObjFileLowering(); + bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection( + MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32, + F); + if (JTInDiffSection) { + // Drop it in the readonly section. + MCSection *ReadOnlySection = TLOF.getSectionForJumpTable(F, TM); + OutStreamer->SwitchSection(ReadOnlySection); + } + + EmitAlignment(Log2_32(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 (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) { + const MachineBasicBlock *MBB = JTBBs[ii]; + if (!EmittedSets.insert(MBB).second) + continue; + + // .set LJTSet, LBB32-base + const MCExpr *LHS = + MCSymbolRefExpr::create(MBB->getSymbol(), OutContext); + OutStreamer->EmitAssignment(GetJTSetSymbol(JTI, MBB->getNumber()), + MCBinaryExpr::createSub(LHS, Base, + OutContext)); + } + } + + // On some targets (e.g. Darwin) we want to emit two consecutive labels + // before each jump table. The first label is never referenced, but tells + // the assembler and linker the extents of the jump table object. The + // second label is actually referenced by the code. + if (JTInDiffSection && DL.hasLinkerPrivateGlobalPrefix()) + // FIXME: This doesn't have to have any specific name, just any randomly + // named and numbered 'l' label would work. Simplify GetJTISymbol. + OutStreamer->EmitLabel(GetJTISymbol(JTI, true)); + + OutStreamer->EmitLabel(GetJTISymbol(JTI)); + + for (unsigned ii = 0, ee = JTBBs.size(); ii != ee; ++ii) + EmitJumpTableEntry(MJTI, JTBBs[ii], JTI); + } + if (!JTInDiffSection) + OutStreamer->EmitDataRegion(MCDR_DataRegionEnd); +} + +/// EmitJumpTableEntry - Emit a jump table entry for the specified MBB to the +/// current stream. +void AsmPrinter::EmitJumpTableEntry(const MachineJumpTableInfo *MJTI, + const MachineBasicBlock *MBB, + unsigned UID) const { + assert(MBB && MBB->getNumber() >= 0 && "Invalid basic block"); + const MCExpr *Value = nullptr; + switch (MJTI->getEntryKind()) { + case MachineJumpTableInfo::EK_Inline: + llvm_unreachable("Cannot emit EK_Inline jump table entry"); + case MachineJumpTableInfo::EK_Custom32: + Value = MF->getSubtarget().getTargetLowering()->LowerCustomJumpTableEntry( + MJTI, MBB, UID, OutContext); + break; + case MachineJumpTableInfo::EK_BlockAddress: + // EK_BlockAddress - Each entry is a plain address of block, e.g.: + // .word LBB123 + Value = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext); + break; + case MachineJumpTableInfo::EK_GPRel32BlockAddress: { + // EK_GPRel32BlockAddress - Each entry is an address of block, encoded + // with a relocation as gp-relative, e.g.: + // .gprel32 LBB123 + MCSymbol *MBBSym = MBB->getSymbol(); + OutStreamer->EmitGPRel32Value(MCSymbolRefExpr::create(MBBSym, OutContext)); + return; + } + + case MachineJumpTableInfo::EK_GPRel64BlockAddress: { + // EK_GPRel64BlockAddress - Each entry is an address of block, encoded + // with a relocation as gp-relative, e.g.: + // .gpdword LBB123 + MCSymbol *MBBSym = MBB->getSymbol(); + OutStreamer->EmitGPRel64Value(MCSymbolRefExpr::create(MBBSym, OutContext)); + return; + } + + case MachineJumpTableInfo::EK_LabelDifference32: { + // Each entry is the address of the block minus the address of the jump + // table. This is used for PIC jump tables where gprel32 is not supported. + // e.g.: + // .word LBB123 - LJTI1_2 + // If the .set directive avoids relocations, this is emitted as: + // .set L4_5_set_123, LBB123 - LJTI1_2 + // .word L4_5_set_123 + if (MAI->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); + } +} + +namespace { + +struct Structor { + int Priority = 0; + Constant *Func = nullptr; + GlobalValue *ComdatKey = nullptr; + + Structor() = default; +}; + +} // end anonymous namespace + +/// EmitXXStructorList - Emit the ctor or dtor list taking into account the init +/// priority. +void AsmPrinter::EmitXXStructorList(const DataLayout &DL, const Constant *List, + bool isCtor) { + // Should be an array of '{ i32, void ()*, i8* }' structs. The first value is the + // init priority. + if (!isa<ConstantArray>(List)) return; + + // Sanity check the structors list. + const ConstantArray *InitList = dyn_cast<ConstantArray>(List); + if (!InitList) return; // Not an array! + StructType *ETy = dyn_cast<StructType>(InitList->getType()->getElementType()); + if (!ETy || ETy->getNumElements() != 3 || + !isa<IntegerType>(ETy->getTypeAtIndex(0U)) || + !isa<PointerType>(ETy->getTypeAtIndex(1U)) || + !isa<PointerType>(ETy->getTypeAtIndex(2U))) + return; // Not (int, ptr, ptr). + + // Gather the structors in a form that's convenient for sorting by priority. + SmallVector<Structor, 8> Structors; + for (Value *O : InitList->operands()) { + ConstantStruct *CS = dyn_cast<ConstantStruct>(O); + if (!CS) continue; // Malformed. + if (CS->getOperand(1)->isNullValue()) + break; // Found a null terminator, skip the rest. + ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0)); + if (!Priority) continue; // Malformed. + Structors.push_back(Structor()); + Structor &S = Structors.back(); + S.Priority = Priority->getLimitedValue(65535); + S.Func = CS->getOperand(1); + if (!CS->getOperand(2)->isNullValue()) + S.ComdatKey = + dyn_cast<GlobalValue>(CS->getOperand(2)->stripPointerCasts()); + } + + // Emit the function pointers in the target-specific order + unsigned Align = Log2_32(DL.getPointerPrefAlignment()); + llvm::stable_sort(Structors, [](const Structor &L, const Structor &R) { + return L.Priority < R.Priority; + }); + for (Structor &S : Structors) { + const TargetLoweringObjectFile &Obj = getObjFileLowering(); + const MCSymbol *KeySym = nullptr; + if (GlobalValue *GV = S.ComdatKey) { + if (GV->isDeclarationForLinker()) + // If the associated variable is not defined in this module + // (it might be available_externally, or have been an + // available_externally definition that was dropped by the + // EliminateAvailableExternally pass), some other TU + // will provide its dynamic initializer. + continue; + + KeySym = getSymbol(GV); + } + MCSection *OutputSection = + (isCtor ? Obj.getStaticCtorSection(S.Priority, KeySym) + : Obj.getStaticDtorSection(S.Priority, KeySym)); + OutStreamer->SwitchSection(OutputSection); + if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection()) + EmitAlignment(Align); + EmitXXStructor(DL, S.Func); + } +} + +void AsmPrinter::EmitModuleIdents(Module &M) { + if (!MAI->hasIdentDirective()) + return; + + if (const NamedMDNode *NMD = M.getNamedMetadata("llvm.ident")) { + for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) { + const MDNode *N = NMD->getOperand(i); + assert(N->getNumOperands() == 1 && + "llvm.ident metadata entry can have only one operand"); + const MDString *S = cast<MDString>(N->getOperand(0)); + OutStreamer->EmitIdent(S->getString()); + } + } +} + +void AsmPrinter::EmitModuleCommandLines(Module &M) { + MCSection *CommandLine = getObjFileLowering().getSectionForCommandLines(); + if (!CommandLine) + return; + + const NamedMDNode *NMD = M.getNamedMetadata("llvm.commandline"); + if (!NMD || !NMD->getNumOperands()) + return; + + OutStreamer->PushSection(); + OutStreamer->SwitchSection(CommandLine); + OutStreamer->EmitZeros(1); + for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) { + const MDNode *N = NMD->getOperand(i); + assert(N->getNumOperands() == 1 && + "llvm.commandline metadata entry can have only one operand"); + const MDString *S = cast<MDString>(N->getOperand(0)); + OutStreamer->EmitBytes(S->getString()); + OutStreamer->EmitZeros(1); + } + OutStreamer->PopSection(); +} + +//===--------------------------------------------------------------------===// +// Emission and print routines +// + +/// Emit a byte directive and value. +/// +void AsmPrinter::emitInt8(int Value) const { + OutStreamer->EmitIntValue(Value, 1); +} + +/// Emit a short directive and value. +void AsmPrinter::emitInt16(int Value) const { + OutStreamer->EmitIntValue(Value, 2); +} + +/// Emit a long directive and value. +void AsmPrinter::emitInt32(int Value) const { + OutStreamer->EmitIntValue(Value, 4); +} + +/// Emit a long long directive and value. +void AsmPrinter::emitInt64(uint64_t Value) const { + OutStreamer->EmitIntValue(Value, 8); +} + +/// Emit something like ".long Hi-Lo" where the size in bytes of the directive +/// is specified by Size and Hi/Lo specify the labels. This implicitly uses +/// .set if it avoids relocations. +void AsmPrinter::EmitLabelDifference(const MCSymbol *Hi, const MCSymbol *Lo, + unsigned Size) const { + OutStreamer->emitAbsoluteSymbolDiff(Hi, Lo, Size); +} + +/// EmitLabelPlusOffset - Emit something like ".long Label+Offset" +/// where the size in bytes of the directive is specified by Size and Label +/// specifies the label. This implicitly uses .set if it is available. +void AsmPrinter::EmitLabelPlusOffset(const MCSymbol *Label, uint64_t Offset, + unsigned Size, + bool IsSectionRelative) const { + if (MAI->needsDwarfSectionOffsetDirective() && IsSectionRelative) { + OutStreamer->EmitCOFFSecRel32(Label, Offset); + if (Size > 4) + OutStreamer->EmitZeros(Size - 4); + return; + } + + // Emit Label+Offset (or just Label if Offset is zero) + const MCExpr *Expr = MCSymbolRefExpr::create(Label, OutContext); + if (Offset) + Expr = MCBinaryExpr::createAdd( + Expr, MCConstantExpr::create(Offset, OutContext), OutContext); + + OutStreamer->EmitValue(Expr, Size); +} + +//===----------------------------------------------------------------------===// + +// EmitAlignment - Emit an alignment directive to the specified power of +// two boundary. For example, if you pass in 3 here, you will get an 8 +// byte alignment. If a global value is specified, and if that global has +// an explicit alignment requested, it will override the alignment request +// if required for correctness. +void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalObject *GV) const { + if (GV) + NumBits = getGVAlignmentLog2(GV, GV->getParent()->getDataLayout(), NumBits); + + if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment. + + assert(NumBits < + static_cast<unsigned>(std::numeric_limits<unsigned>::digits) && + "undefined behavior"); + if (getCurrentSection()->getKind().isText()) + OutStreamer->EmitCodeAlignment(1u << NumBits); + else + OutStreamer->EmitValueToAlignment(1u << NumBits); +} + +//===----------------------------------------------------------------------===// +// Constant emission. +//===----------------------------------------------------------------------===// + +const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) { + MCContext &Ctx = OutContext; + + if (CV->isNullValue() || isa<UndefValue>(CV)) + return MCConstantExpr::create(0, Ctx); + + if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) + return MCConstantExpr::create(CI->getZExtValue(), Ctx); + + if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) + return MCSymbolRefExpr::create(getSymbol(GV), Ctx); + + if (const BlockAddress *BA = dyn_cast<BlockAddress>(CV)) + return MCSymbolRefExpr::create(GetBlockAddressSymbol(BA), Ctx); + + const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV); + if (!CE) { + llvm_unreachable("Unknown constant value to lower!"); + } + + switch (CE->getOpcode()) { + default: + // If the code isn't optimized, there may be outstanding folding + // opportunities. Attempt to fold the expression using DataLayout as a + // last resort before giving up. + if (Constant *C = ConstantFoldConstant(CE, getDataLayout())) + if (C != CE) + return lowerConstant(C); + + // Otherwise report the problem to the user. + { + std::string S; + raw_string_ostream OS(S); + OS << "Unsupported expression in static initializer: "; + CE->printAsOperand(OS, /*PrintType=*/false, + !MF ? nullptr : MF->getFunction().getParent()); + report_fatal_error(OS.str()); + } + case Instruction::GetElementPtr: { + // Generate a symbolic expression for the byte address + APInt OffsetAI(getDataLayout().getPointerTypeSizeInBits(CE->getType()), 0); + cast<GEPOperator>(CE)->accumulateConstantOffset(getDataLayout(), OffsetAI); + + const MCExpr *Base = lowerConstant(CE->getOperand(0)); + if (!OffsetAI) + return Base; + + int64_t Offset = OffsetAI.getSExtValue(); + return MCBinaryExpr::createAdd(Base, MCConstantExpr::create(Offset, Ctx), + Ctx); + } + + case Instruction::Trunc: + // We emit the value and depend on the assembler to truncate the generated + // expression properly. This is important for differences between + // blockaddress labels. Since the two labels are in the same function, it + // is reasonable to treat their delta as a 32-bit value. + LLVM_FALLTHROUGH; + case Instruction::BitCast: + return lowerConstant(CE->getOperand(0)); + + case Instruction::IntToPtr: { + const DataLayout &DL = getDataLayout(); + + // Handle casts to pointers by changing them into casts to the appropriate + // integer type. This promotes constant folding and simplifies this code. + Constant *Op = CE->getOperand(0); + Op = ConstantExpr::getIntegerCast(Op, DL.getIntPtrType(CV->getType()), + false/*ZExt*/); + return lowerConstant(Op); + } + + case Instruction::PtrToInt: { + const DataLayout &DL = getDataLayout(); + + // Support only foldable casts to/from pointers that can be eliminated by + // changing the pointer to the appropriately sized integer type. + Constant *Op = CE->getOperand(0); + Type *Ty = CE->getType(); + + const MCExpr *OpExpr = lowerConstant(Op); + + // We can emit the pointer value into this slot if the slot is an + // integer slot equal to the size of the pointer. + // + // If the pointer is larger than the resultant integer, then + // as with Trunc just depend on the assembler to truncate it. + if (DL.getTypeAllocSize(Ty) <= DL.getTypeAllocSize(Op->getType())) + return OpExpr; + + // Otherwise the pointer is smaller than the resultant integer, mask off + // the high bits so we are sure to get a proper truncation if the input is + // a constant expr. + unsigned InBits = DL.getTypeAllocSizeInBits(Op->getType()); + const MCExpr *MaskExpr = MCConstantExpr::create(~0ULL >> (64-InBits), Ctx); + return MCBinaryExpr::createAnd(OpExpr, MaskExpr, Ctx); + } + + case Instruction::Sub: { + GlobalValue *LHSGV; + APInt LHSOffset; + if (IsConstantOffsetFromGlobal(CE->getOperand(0), LHSGV, LHSOffset, + getDataLayout())) { + GlobalValue *RHSGV; + APInt RHSOffset; + if (IsConstantOffsetFromGlobal(CE->getOperand(1), RHSGV, RHSOffset, + getDataLayout())) { + const MCExpr *RelocExpr = + getObjFileLowering().lowerRelativeReference(LHSGV, RHSGV, TM); + if (!RelocExpr) + RelocExpr = MCBinaryExpr::createSub( + MCSymbolRefExpr::create(getSymbol(LHSGV), Ctx), + MCSymbolRefExpr::create(getSymbol(RHSGV), Ctx), Ctx); + int64_t Addend = (LHSOffset - RHSOffset).getSExtValue(); + if (Addend != 0) + RelocExpr = MCBinaryExpr::createAdd( + RelocExpr, MCConstantExpr::create(Addend, Ctx), Ctx); + return RelocExpr; + } + } + } + // else fallthrough + LLVM_FALLTHROUGH; + + // The MC library also has a right-shift operator, but it isn't consistently + // signed or unsigned between different targets. + case Instruction::Add: + case Instruction::Mul: + case Instruction::SDiv: + case Instruction::SRem: + case Instruction::Shl: + case Instruction::And: + case Instruction::Or: + case Instruction::Xor: { + const MCExpr *LHS = lowerConstant(CE->getOperand(0)); + const MCExpr *RHS = lowerConstant(CE->getOperand(1)); + switch (CE->getOpcode()) { + default: llvm_unreachable("Unknown binary operator constant cast expr"); + case Instruction::Add: return MCBinaryExpr::createAdd(LHS, RHS, Ctx); + case Instruction::Sub: return MCBinaryExpr::createSub(LHS, RHS, Ctx); + case Instruction::Mul: return MCBinaryExpr::createMul(LHS, RHS, Ctx); + case Instruction::SDiv: return MCBinaryExpr::createDiv(LHS, RHS, Ctx); + case Instruction::SRem: return MCBinaryExpr::createMod(LHS, RHS, Ctx); + case Instruction::Shl: return MCBinaryExpr::createShl(LHS, RHS, Ctx); + case Instruction::And: return MCBinaryExpr::createAnd(LHS, RHS, Ctx); + case Instruction::Or: return MCBinaryExpr::createOr (LHS, RHS, Ctx); + case Instruction::Xor: return MCBinaryExpr::createXor(LHS, RHS, Ctx); + } + } + } +} + +static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *C, + AsmPrinter &AP, + const Constant *BaseCV = nullptr, + uint64_t Offset = 0); + +static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP); +static void emitGlobalConstantFP(APFloat APF, Type *ET, AsmPrinter &AP); + +/// isRepeatedByteSequence - Determine whether the given value is +/// composed of a repeated sequence of identical bytes and return the +/// byte value. If it is not a repeated sequence, return -1. +static int isRepeatedByteSequence(const ConstantDataSequential *V) { + StringRef Data = V->getRawDataValues(); + assert(!Data.empty() && "Empty aggregates should be CAZ node"); + char C = Data[0]; + for (unsigned i = 1, e = Data.size(); i != e; ++i) + if (Data[i] != C) return -1; + return static_cast<uint8_t>(C); // Ensure 255 is not returned as -1. +} + +/// isRepeatedByteSequence - Determine whether the given value is +/// composed of a repeated sequence of identical bytes and return the +/// byte value. If it is not a repeated sequence, return -1. +static int isRepeatedByteSequence(const Value *V, const DataLayout &DL) { + if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) { + uint64_t Size = DL.getTypeAllocSizeInBits(V->getType()); + assert(Size % 8 == 0); + + // Extend the element to take zero padding into account. + APInt Value = CI->getValue().zextOrSelf(Size); + if (!Value.isSplat(8)) + return -1; + + return Value.zextOrTrunc(8).getZExtValue(); + } + if (const ConstantArray *CA = dyn_cast<ConstantArray>(V)) { + // Make sure all array elements are sequences of the same repeated + // byte. + assert(CA->getNumOperands() != 0 && "Should be a CAZ"); + Constant *Op0 = CA->getOperand(0); + int Byte = isRepeatedByteSequence(Op0, DL); + if (Byte == -1) + return -1; + + // All array elements must be equal. + for (unsigned i = 1, e = CA->getNumOperands(); i != e; ++i) + if (CA->getOperand(i) != Op0) + return -1; + return Byte; + } + + if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(V)) + return isRepeatedByteSequence(CDS); + + return -1; +} + +static void emitGlobalConstantDataSequential(const DataLayout &DL, + const ConstantDataSequential *CDS, + AsmPrinter &AP) { + // See if we can aggregate this into a .fill, if so, emit it as such. + int Value = isRepeatedByteSequence(CDS, DL); + if (Value != -1) { + uint64_t Bytes = DL.getTypeAllocSize(CDS->getType()); + // Don't emit a 1-byte object as a .fill. + if (Bytes > 1) + return AP.OutStreamer->emitFill(Bytes, Value); + } + + // If this can be emitted with .ascii/.asciz, emit it as such. + if (CDS->isString()) + return AP.OutStreamer->EmitBytes(CDS->getAsString()); + + // Otherwise, emit the values in successive locations. + unsigned ElementByteSize = CDS->getElementByteSize(); + if (isa<IntegerType>(CDS->getElementType())) { + for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) { + if (AP.isVerbose()) + AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n", + CDS->getElementAsInteger(i)); + AP.OutStreamer->EmitIntValue(CDS->getElementAsInteger(i), + ElementByteSize); + } + } else { + Type *ET = CDS->getElementType(); + for (unsigned I = 0, E = CDS->getNumElements(); I != E; ++I) + emitGlobalConstantFP(CDS->getElementAsAPFloat(I), ET, AP); + } + + unsigned Size = DL.getTypeAllocSize(CDS->getType()); + unsigned EmittedSize = DL.getTypeAllocSize(CDS->getType()->getElementType()) * + CDS->getNumElements(); + assert(EmittedSize <= Size && "Size cannot be less than EmittedSize!"); + if (unsigned Padding = Size - EmittedSize) + AP.OutStreamer->EmitZeros(Padding); +} + +static void emitGlobalConstantArray(const DataLayout &DL, + const ConstantArray *CA, AsmPrinter &AP, + const Constant *BaseCV, uint64_t Offset) { + // See if we can aggregate some values. Make sure it can be + // represented as a series of bytes of the constant value. + int Value = isRepeatedByteSequence(CA, DL); + + if (Value != -1) { + uint64_t Bytes = DL.getTypeAllocSize(CA->getType()); + AP.OutStreamer->emitFill(Bytes, Value); + } + else { + for (unsigned i = 0, e = CA->getNumOperands(); i != e; ++i) { + emitGlobalConstantImpl(DL, CA->getOperand(i), AP, BaseCV, Offset); + Offset += DL.getTypeAllocSize(CA->getOperand(i)->getType()); + } + } +} + +static void emitGlobalConstantVector(const DataLayout &DL, + const ConstantVector *CV, AsmPrinter &AP) { + for (unsigned i = 0, e = CV->getType()->getNumElements(); i != e; ++i) + emitGlobalConstantImpl(DL, CV->getOperand(i), AP); + + unsigned Size = DL.getTypeAllocSize(CV->getType()); + unsigned EmittedSize = DL.getTypeAllocSize(CV->getType()->getElementType()) * + CV->getType()->getNumElements(); + if (unsigned Padding = Size - EmittedSize) + AP.OutStreamer->EmitZeros(Padding); +} + +static void emitGlobalConstantStruct(const DataLayout &DL, + const ConstantStruct *CS, AsmPrinter &AP, + const Constant *BaseCV, uint64_t Offset) { + // Print the fields in successive locations. Pad to align if needed! + unsigned Size = DL.getTypeAllocSize(CS->getType()); + const StructLayout *Layout = DL.getStructLayout(CS->getType()); + uint64_t SizeSoFar = 0; + for (unsigned i = 0, e = CS->getNumOperands(); i != e; ++i) { + const Constant *Field = CS->getOperand(i); + + // Print the actual field value. + emitGlobalConstantImpl(DL, Field, AP, BaseCV, Offset + SizeSoFar); + + // Check if padding is needed and insert one or more 0s. + uint64_t FieldSize = DL.getTypeAllocSize(Field->getType()); + uint64_t PadSize = ((i == e-1 ? Size : Layout->getElementOffset(i+1)) + - Layout->getElementOffset(i)) - FieldSize; + SizeSoFar += FieldSize + PadSize; + + // Insert padding - this may include padding to increase the size of the + // current field up to the ABI size (if the struct is not packed) as well + // as padding to ensure that the next field starts at the right offset. + AP.OutStreamer->EmitZeros(PadSize); + } + assert(SizeSoFar == Layout->getSizeInBytes() && + "Layout of constant struct may be incorrect!"); +} + +static void emitGlobalConstantFP(APFloat APF, Type *ET, AsmPrinter &AP) { + APInt API = APF.bitcastToAPInt(); + + // First print a comment with what we think the original floating-point value + // should have been. + if (AP.isVerbose()) { + SmallString<8> StrVal; + APF.toString(StrVal); + + if (ET) + ET->print(AP.OutStreamer->GetCommentOS()); + else + AP.OutStreamer->GetCommentOS() << "Printing <null> Type"; + AP.OutStreamer->GetCommentOS() << ' ' << StrVal << '\n'; + } + + // Now iterate through the APInt chunks, emitting them in endian-correct + // order, possibly with a smaller chunk at beginning/end (e.g. for x87 80-bit + // floats). + unsigned NumBytes = API.getBitWidth() / 8; + unsigned TrailingBytes = NumBytes % sizeof(uint64_t); + const uint64_t *p = API.getRawData(); + + // PPC's long double has odd notions of endianness compared to how LLVM + // handles it: p[0] goes first for *big* endian on PPC. + if (AP.getDataLayout().isBigEndian() && !ET->isPPC_FP128Ty()) { + int Chunk = API.getNumWords() - 1; + + if (TrailingBytes) + AP.OutStreamer->EmitIntValue(p[Chunk--], TrailingBytes); + + for (; Chunk >= 0; --Chunk) + AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t)); + } else { + unsigned Chunk; + for (Chunk = 0; Chunk < NumBytes / sizeof(uint64_t); ++Chunk) + AP.OutStreamer->EmitIntValue(p[Chunk], sizeof(uint64_t)); + + if (TrailingBytes) + AP.OutStreamer->EmitIntValue(p[Chunk], TrailingBytes); + } + + // Emit the tail padding for the long double. + const DataLayout &DL = AP.getDataLayout(); + AP.OutStreamer->EmitZeros(DL.getTypeAllocSize(ET) - DL.getTypeStoreSize(ET)); +} + +static void emitGlobalConstantFP(const ConstantFP *CFP, AsmPrinter &AP) { + emitGlobalConstantFP(CFP->getValueAPF(), CFP->getType(), AP); +} + +static void emitGlobalConstantLargeInt(const ConstantInt *CI, AsmPrinter &AP) { + const DataLayout &DL = AP.getDataLayout(); + unsigned BitWidth = CI->getBitWidth(); + + // Copy the value as we may massage the layout for constants whose bit width + // is not a multiple of 64-bits. + APInt Realigned(CI->getValue()); + uint64_t ExtraBits = 0; + unsigned ExtraBitsSize = BitWidth & 63; + + if (ExtraBitsSize) { + // The bit width of the data is not a multiple of 64-bits. + // The extra bits are expected to be at the end of the chunk of the memory. + // Little endian: + // * Nothing to be done, just record the extra bits to emit. + // Big endian: + // * Record the extra bits to emit. + // * Realign the raw data to emit the chunks of 64-bits. + if (DL.isBigEndian()) { + // Basically the structure of the raw data is a chunk of 64-bits cells: + // 0 1 BitWidth / 64 + // [chunk1][chunk2] ... [chunkN]. + // The most significant chunk is chunkN and it should be emitted first. + // However, due to the alignment issue chunkN contains useless bits. + // Realign the chunks so that they contain only useless information: + // ExtraBits 0 1 (BitWidth / 64) - 1 + // chu[nk1 chu][nk2 chu] ... [nkN-1 chunkN] + ExtraBits = Realigned.getRawData()[0] & + (((uint64_t)-1) >> (64 - ExtraBitsSize)); + Realigned.lshrInPlace(ExtraBitsSize); + } else + ExtraBits = Realigned.getRawData()[BitWidth / 64]; + } + + // We don't expect assemblers to support integer data directives + // for more than 64 bits, so we emit the data in at most 64-bit + // quantities at a time. + const uint64_t *RawData = Realigned.getRawData(); + for (unsigned i = 0, e = BitWidth / 64; i != e; ++i) { + uint64_t Val = DL.isBigEndian() ? RawData[e - i - 1] : RawData[i]; + AP.OutStreamer->EmitIntValue(Val, 8); + } + + if (ExtraBitsSize) { + // Emit the extra bits after the 64-bits chunks. + + // Emit a directive that fills the expected size. + uint64_t Size = AP.getDataLayout().getTypeAllocSize(CI->getType()); + Size -= (BitWidth / 64) * 8; + assert(Size && Size * 8 >= ExtraBitsSize && + (ExtraBits & (((uint64_t)-1) >> (64 - ExtraBitsSize))) + == ExtraBits && "Directive too small for extra bits."); + AP.OutStreamer->EmitIntValue(ExtraBits, Size); + } +} + +/// Transform a not absolute MCExpr containing a reference to a GOT +/// equivalent global, by a target specific GOT pc relative access to the +/// final symbol. +static void handleIndirectSymViaGOTPCRel(AsmPrinter &AP, const MCExpr **ME, + const Constant *BaseCst, + uint64_t Offset) { + // The global @foo below illustrates a global that uses a got equivalent. + // + // @bar = global i32 42 + // @gotequiv = private unnamed_addr constant i32* @bar + // @foo = i32 trunc (i64 sub (i64 ptrtoint (i32** @gotequiv to i64), + // i64 ptrtoint (i32* @foo to i64)) + // to i32) + // + // The cstexpr in @foo is converted into the MCExpr `ME`, where we actually + // check whether @foo is suitable to use a GOTPCREL. `ME` is usually in the + // form: + // + // foo = cstexpr, where + // cstexpr := <gotequiv> - "." + <cst> + // cstexpr := <gotequiv> - (<foo> - <offset from @foo base>) + <cst> + // + // After canonicalization by evaluateAsRelocatable `ME` turns into: + // + // cstexpr := <gotequiv> - <foo> + gotpcrelcst, where + // gotpcrelcst := <offset from @foo base> + <cst> + MCValue MV; + if (!(*ME)->evaluateAsRelocatable(MV, nullptr, nullptr) || MV.isAbsolute()) + return; + const MCSymbolRefExpr *SymA = MV.getSymA(); + if (!SymA) + return; + + // Check that GOT equivalent symbol is cached. + const MCSymbol *GOTEquivSym = &SymA->getSymbol(); + if (!AP.GlobalGOTEquivs.count(GOTEquivSym)) + return; + + const GlobalValue *BaseGV = dyn_cast_or_null<GlobalValue>(BaseCst); + if (!BaseGV) + return; + + // Check for a valid base symbol + const MCSymbol *BaseSym = AP.getSymbol(BaseGV); + const MCSymbolRefExpr *SymB = MV.getSymB(); + + if (!SymB || BaseSym != &SymB->getSymbol()) + return; + + // Make sure to match: + // + // gotpcrelcst := <offset from @foo base> + <cst> + // + // If gotpcrelcst is positive it means that we can safely fold the pc rel + // displacement into the GOTPCREL. We can also can have an extra offset <cst> + // if the target knows how to encode it. + int64_t GOTPCRelCst = Offset + MV.getConstant(); + if (GOTPCRelCst < 0) + return; + if (!AP.getObjFileLowering().supportGOTPCRelWithOffset() && GOTPCRelCst != 0) + return; + + // Emit the GOT PC relative to replace the got equivalent global, i.e.: + // + // bar: + // .long 42 + // gotequiv: + // .quad bar + // foo: + // .long gotequiv - "." + <cst> + // + // is replaced by the target specific equivalent to: + // + // bar: + // .long 42 + // foo: + // .long bar@GOTPCREL+<gotpcrelcst> + AsmPrinter::GOTEquivUsePair Result = AP.GlobalGOTEquivs[GOTEquivSym]; + const GlobalVariable *GV = Result.first; + int NumUses = (int)Result.second; + const GlobalValue *FinalGV = dyn_cast<GlobalValue>(GV->getOperand(0)); + const MCSymbol *FinalSym = AP.getSymbol(FinalGV); + *ME = AP.getObjFileLowering().getIndirectSymViaGOTPCRel( + FinalSym, MV, Offset, AP.MMI, *AP.OutStreamer); + + // Update GOT equivalent usage information + --NumUses; + if (NumUses >= 0) + AP.GlobalGOTEquivs[GOTEquivSym] = std::make_pair(GV, NumUses); +} + +static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV, + AsmPrinter &AP, const Constant *BaseCV, + uint64_t Offset) { + uint64_t Size = DL.getTypeAllocSize(CV->getType()); + + // Globals with sub-elements such as combinations of arrays and structs + // are handled recursively by emitGlobalConstantImpl. Keep track of the + // constant symbol base and the current position with BaseCV and Offset. + if (!BaseCV && CV->hasOneUse()) + BaseCV = dyn_cast<Constant>(CV->user_back()); + + if (isa<ConstantAggregateZero>(CV) || isa<UndefValue>(CV)) + return AP.OutStreamer->EmitZeros(Size); + + if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) { + switch (Size) { + case 1: + case 2: + case 4: + case 8: + if (AP.isVerbose()) + AP.OutStreamer->GetCommentOS() << format("0x%" PRIx64 "\n", + CI->getZExtValue()); + AP.OutStreamer->EmitIntValue(CI->getZExtValue(), Size); + return; + default: + emitGlobalConstantLargeInt(CI, AP); + return; + } + } + + if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) + return emitGlobalConstantFP(CFP, AP); + + if (isa<ConstantPointerNull>(CV)) { + AP.OutStreamer->EmitIntValue(0, Size); + return; + } + + if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(CV)) + return emitGlobalConstantDataSequential(DL, CDS, AP); + + if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) + return emitGlobalConstantArray(DL, CVA, AP, BaseCV, Offset); + + if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) + return emitGlobalConstantStruct(DL, CVS, AP, BaseCV, Offset); + + if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) { + // Look through bitcasts, which might not be able to be MCExpr'ized (e.g. of + // vectors). + if (CE->getOpcode() == Instruction::BitCast) + return emitGlobalConstantImpl(DL, CE->getOperand(0), AP); + + if (Size > 8) { + // If the constant expression's size is greater than 64-bits, then we have + // to emit the value in chunks. Try to constant fold the value and emit it + // that way. + Constant *New = ConstantFoldConstant(CE, DL); + if (New && New != CE) + return emitGlobalConstantImpl(DL, New, AP); + } + } + + if (const ConstantVector *V = dyn_cast<ConstantVector>(CV)) + return emitGlobalConstantVector(DL, V, AP); + + // Otherwise, it must be a ConstantExpr. Lower it to an MCExpr, then emit it + // thread the streamer with EmitValue. + const MCExpr *ME = AP.lowerConstant(CV); + + // Since lowerConstant already folded and got rid of all IR pointer and + // integer casts, detect GOT equivalent accesses by looking into the MCExpr + // directly. + if (AP.getObjFileLowering().supportIndirectSymViaGOTPCRel()) + handleIndirectSymViaGOTPCRel(AP, &ME, BaseCV, Offset); + + AP.OutStreamer->EmitValue(ME, Size); +} + +/// EmitGlobalConstant - Print a general LLVM constant to the .s file. +void AsmPrinter::EmitGlobalConstant(const DataLayout &DL, const Constant *CV) { + uint64_t Size = DL.getTypeAllocSize(CV->getType()); + if (Size) + emitGlobalConstantImpl(DL, CV, *this); + else if (MAI->hasSubsectionsViaSymbols()) { + // If the global has zero size, emit a single byte so that two labels don't + // look like they are at the same location. + OutStreamer->EmitIntValue(0, 1); + } +} + +void AsmPrinter::EmitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) { + // Target doesn't support this yet! + llvm_unreachable("Target does not support EmitMachineConstantPoolValue"); +} + +void AsmPrinter::printOffset(int64_t Offset, raw_ostream &OS) const { + if (Offset > 0) + OS << '+' << Offset; + else if (Offset < 0) + OS << Offset; +} + +//===----------------------------------------------------------------------===// +// Symbol Lowering Routines. +//===----------------------------------------------------------------------===// + +MCSymbol *AsmPrinter::createTempSymbol(const Twine &Name) const { + return OutContext.createTempSymbol(Name, true); +} + +MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BlockAddress *BA) const { + return MMI->getAddrLabelSymbol(BA->getBasicBlock()); +} + +MCSymbol *AsmPrinter::GetBlockAddressSymbol(const BasicBlock *BB) const { + return MMI->getAddrLabelSymbol(BB); +} + +/// GetCPISymbol - Return the symbol for the specified constant pool entry. +MCSymbol *AsmPrinter::GetCPISymbol(unsigned CPID) const { + if (getSubtargetInfo().getTargetTriple().isWindowsMSVCEnvironment()) { + const MachineConstantPoolEntry &CPE = + MF->getConstantPool()->getConstants()[CPID]; + if (!CPE.isMachineConstantPoolEntry()) { + const DataLayout &DL = MF->getDataLayout(); + SectionKind Kind = CPE.getSectionKind(&DL); + const Constant *C = CPE.Val.ConstVal; + unsigned Align = CPE.Alignment; + if (const MCSectionCOFF *S = dyn_cast<MCSectionCOFF>( + getObjFileLowering().getSectionForConstant(DL, Kind, C, Align))) { + if (MCSymbol *Sym = S->getCOMDATSymbol()) { + if (Sym->isUndefined()) + OutStreamer->EmitSymbolAttribute(Sym, MCSA_Global); + return Sym; + } + } + } + } + + const DataLayout &DL = getDataLayout(); + return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) + + "CPI" + Twine(getFunctionNumber()) + "_" + + Twine(CPID)); +} + +/// GetJTISymbol - Return the symbol for the specified jump table entry. +MCSymbol *AsmPrinter::GetJTISymbol(unsigned JTID, bool isLinkerPrivate) const { + return MF->getJTISymbol(JTID, OutContext, isLinkerPrivate); +} + +/// GetJTSetSymbol - Return the symbol for the specified jump table .set +/// FIXME: privatize to AsmPrinter. +MCSymbol *AsmPrinter::GetJTSetSymbol(unsigned UID, unsigned MBBID) const { + const DataLayout &DL = getDataLayout(); + return OutContext.getOrCreateSymbol(Twine(DL.getPrivateGlobalPrefix()) + + Twine(getFunctionNumber()) + "_" + + Twine(UID) + "_set_" + Twine(MBBID)); +} + +MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV, + StringRef Suffix) const { + return getObjFileLowering().getSymbolWithGlobalValueBase(GV, Suffix, TM); +} + +/// Return the MCSymbol for the specified ExternalSymbol. +MCSymbol *AsmPrinter::GetExternalSymbolSymbol(StringRef Sym) const { + SmallString<60> NameStr; + Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout()); + return OutContext.getOrCreateSymbol(NameStr); +} + +/// PrintParentLoopComment - Print comments about parent loops of this one. +static void PrintParentLoopComment(raw_ostream &OS, const MachineLoop *Loop, + unsigned FunctionNumber) { + if (!Loop) return; + PrintParentLoopComment(OS, Loop->getParentLoop(), FunctionNumber); + OS.indent(Loop->getLoopDepth()*2) + << "Parent Loop BB" << FunctionNumber << "_" + << Loop->getHeader()->getNumber() + << " Depth=" << Loop->getLoopDepth() << '\n'; +} + +/// PrintChildLoopComment - Print comments about child loops within +/// the loop for this basic block, with nesting. +static void PrintChildLoopComment(raw_ostream &OS, const MachineLoop *Loop, + unsigned FunctionNumber) { + // Add child loop information + for (const MachineLoop *CL : *Loop) { + OS.indent(CL->getLoopDepth()*2) + << "Child Loop BB" << FunctionNumber << "_" + << CL->getHeader()->getNumber() << " Depth " << CL->getLoopDepth() + << '\n'; + PrintChildLoopComment(OS, CL, FunctionNumber); + } +} + +/// emitBasicBlockLoopComments - Pretty-print comments for basic blocks. +static void emitBasicBlockLoopComments(const MachineBasicBlock &MBB, + const MachineLoopInfo *LI, + const AsmPrinter &AP) { + // Add loop depth information + const MachineLoop *Loop = LI->getLoopFor(&MBB); + if (!Loop) return; + + MachineBasicBlock *Header = Loop->getHeader(); + assert(Header && "No header for loop"); + + // If this block is not a loop header, just print out what is the loop header + // and return. + if (Header != &MBB) { + AP.OutStreamer->AddComment(" in Loop: Header=BB" + + Twine(AP.getFunctionNumber())+"_" + + Twine(Loop->getHeader()->getNumber())+ + " Depth="+Twine(Loop->getLoopDepth())); + return; + } + + // Otherwise, it is a loop header. Print out information about child and + // parent loops. + raw_ostream &OS = AP.OutStreamer->GetCommentOS(); + + PrintParentLoopComment(OS, Loop->getParentLoop(), AP.getFunctionNumber()); + + OS << "=>"; + OS.indent(Loop->getLoopDepth()*2-2); + + OS << "This "; + if (Loop->empty()) + OS << "Inner "; + OS << "Loop Header: Depth=" + Twine(Loop->getLoopDepth()) << '\n'; + + PrintChildLoopComment(OS, Loop, AP.getFunctionNumber()); +} + +void AsmPrinter::setupCodePaddingContext(const MachineBasicBlock &MBB, + MCCodePaddingContext &Context) const { + assert(MF != nullptr && "Machine function must be valid"); + Context.IsPaddingActive = !MF->hasInlineAsm() && + !MF->getFunction().hasOptSize() && + TM.getOptLevel() != CodeGenOpt::None; + Context.IsBasicBlockReachableViaFallthrough = + std::find(MBB.pred_begin(), MBB.pred_end(), MBB.getPrevNode()) != + MBB.pred_end(); + Context.IsBasicBlockReachableViaBranch = + MBB.pred_size() > 0 && !isBlockOnlyReachableByFallthrough(&MBB); +} + +/// EmitBasicBlockStart - This method prints the label for the specified +/// MachineBasicBlock, an alignment (if present) and a comment describing +/// it if appropriate. +void AsmPrinter::EmitBasicBlockStart(const MachineBasicBlock &MBB) const { + // End the previous funclet and start a new one. + if (MBB.isEHFuncletEntry()) { + for (const HandlerInfo &HI : Handlers) { + HI.Handler->endFunclet(); + HI.Handler->beginFunclet(MBB); + } + } + + // Emit an alignment directive for this block, if needed. + if (unsigned Align = MBB.getAlignment()) + EmitAlignment(Align); + MCCodePaddingContext Context; + setupCodePaddingContext(MBB, Context); + OutStreamer->EmitCodePaddingBasicBlockStart(Context); + + // If the block has its address taken, emit any labels that were used to + // reference the block. It is possible that there is more than one label + // here, because multiple LLVM BB's may have been RAUW'd to this block after + // the references were generated. + if (MBB.hasAddressTaken()) { + const BasicBlock *BB = MBB.getBasicBlock(); + if (isVerbose()) + OutStreamer->AddComment("Block address taken"); + + // MBBs can have their address taken as part of CodeGen without having + // their corresponding BB's address taken in IR + if (BB->hasAddressTaken()) + for (MCSymbol *Sym : MMI->getAddrLabelSymbolToEmit(BB)) + OutStreamer->EmitLabel(Sym); + } + + // Print some verbose block comments. + if (isVerbose()) { + if (const BasicBlock *BB = MBB.getBasicBlock()) { + if (BB->hasName()) { + BB->printAsOperand(OutStreamer->GetCommentOS(), + /*PrintType=*/false, BB->getModule()); + OutStreamer->GetCommentOS() << '\n'; + } + } + + assert(MLI != nullptr && "MachineLoopInfo should has been computed"); + emitBasicBlockLoopComments(MBB, MLI, *this); + } + + // Print the main label for the block. + if (MBB.pred_empty() || + (isBlockOnlyReachableByFallthrough(&MBB) && !MBB.isEHFuncletEntry() && + !MBB.hasLabelMustBeEmitted())) { + if (isVerbose()) { + // NOTE: Want this comment at start of line, don't emit with AddComment. + OutStreamer->emitRawComment(" %bb." + Twine(MBB.getNumber()) + ":", + false); + } + } else { + if (isVerbose() && MBB.hasLabelMustBeEmitted()) + OutStreamer->AddComment("Label of block must be emitted"); + OutStreamer->EmitLabel(MBB.getSymbol()); + } +} + +void AsmPrinter::EmitBasicBlockEnd(const MachineBasicBlock &MBB) { + MCCodePaddingContext Context; + setupCodePaddingContext(MBB, Context); + OutStreamer->EmitCodePaddingBasicBlockEnd(Context); +} + +void AsmPrinter::EmitVisibility(MCSymbol *Sym, unsigned Visibility, + bool IsDefinition) const { + MCSymbolAttr Attr = MCSA_Invalid; + + switch (Visibility) { + default: break; + case GlobalValue::HiddenVisibility: + if (IsDefinition) + Attr = MAI->getHiddenVisibilityAttr(); + else + Attr = MAI->getHiddenDeclarationVisibilityAttr(); + break; + case GlobalValue::ProtectedVisibility: + Attr = MAI->getProtectedVisibilityAttr(); + break; + } + + if (Attr != MCSA_Invalid) + OutStreamer->EmitSymbolAttribute(Sym, Attr); +} + +/// isBlockOnlyReachableByFallthough - Return true if the basic block has +/// exactly one predecessor and the control transfer mechanism between +/// the predecessor and this block is a fall-through. +bool AsmPrinter:: +isBlockOnlyReachableByFallthrough(const MachineBasicBlock *MBB) const { + // If this is a landing pad, it isn't a fall through. If it has no preds, + // then nothing falls through to it. + if (MBB->isEHPad() || MBB->pred_empty()) + return false; + + // If there isn't exactly one predecessor, it can't be a fall through. + if (MBB->pred_size() > 1) + return false; + + // The predecessor has to be immediately before this block. + MachineBasicBlock *Pred = *MBB->pred_begin(); + if (!Pred->isLayoutSuccessor(MBB)) + return false; + + // If the block is completely empty, then it definitely does fall through. + if (Pred->empty()) + return true; + + // Check the terminators in the previous blocks + for (const auto &MI : Pred->terminators()) { + // If it is not a simple branch, we are in a table somewhere. + if (!MI.isBranch() || MI.isIndirectBranch()) + return false; + + // If we are the operands of one of the branches, this is not a fall + // through. Note that targets with delay slots will usually bundle + // terminators with the delay slot instruction. + for (ConstMIBundleOperands OP(MI); OP.isValid(); ++OP) { + if (OP->isJTI()) + return false; + if (OP->isMBB() && OP->getMBB() == MBB) + return false; + } + } + + return true; +} + +GCMetadataPrinter *AsmPrinter::GetOrCreateGCPrinter(GCStrategy &S) { + if (!S.usesMetadata()) + return nullptr; + + gcp_map_type &GCMap = getGCMap(GCMetadataPrinters); + gcp_map_type::iterator GCPI = GCMap.find(&S); + if (GCPI != GCMap.end()) + return GCPI->second.get(); + + auto Name = S.getName(); + + for (GCMetadataPrinterRegistry::iterator + I = GCMetadataPrinterRegistry::begin(), + E = GCMetadataPrinterRegistry::end(); I != E; ++I) + if (Name == I->getName()) { + std::unique_ptr<GCMetadataPrinter> GMP = I->instantiate(); + GMP->S = &S; + auto IterBool = GCMap.insert(std::make_pair(&S, std::move(GMP))); + return IterBool.first->second.get(); + } + + report_fatal_error("no GCMetadataPrinter registered for GC: " + Twine(Name)); +} + +void AsmPrinter::emitStackMaps(StackMaps &SM) { + GCModuleInfo *MI = getAnalysisIfAvailable<GCModuleInfo>(); + assert(MI && "AsmPrinter didn't require GCModuleInfo?"); + bool NeedsDefault = false; + if (MI->begin() == MI->end()) + // No GC strategy, use the default format. + NeedsDefault = true; + else + for (auto &I : *MI) { + if (GCMetadataPrinter *MP = GetOrCreateGCPrinter(*I)) + if (MP->emitStackMaps(SM, *this)) + continue; + // The strategy doesn't have printer or doesn't emit custom stack maps. + // Use the default format. + NeedsDefault = true; + } + + if (NeedsDefault) + SM.serializeToStackMapSection(); +} + +/// Pin vtable to this file. +AsmPrinterHandler::~AsmPrinterHandler() = default; + +void AsmPrinterHandler::markFunctionEnd() {} + +// In the binary's "xray_instr_map" section, an array of these function entries +// describes each instrumentation point. When XRay patches your code, the index +// into this table will be given to your handler as a patch point identifier. +void AsmPrinter::XRayFunctionEntry::emit(int Bytes, MCStreamer *Out, + const MCSymbol *CurrentFnSym) const { + Out->EmitSymbolValue(Sled, Bytes); + Out->EmitSymbolValue(CurrentFnSym, Bytes); + auto Kind8 = static_cast<uint8_t>(Kind); + Out->EmitBinaryData(StringRef(reinterpret_cast<const char *>(&Kind8), 1)); + Out->EmitBinaryData( + StringRef(reinterpret_cast<const char *>(&AlwaysInstrument), 1)); + Out->EmitBinaryData(StringRef(reinterpret_cast<const char *>(&Version), 1)); + auto Padding = (4 * Bytes) - ((2 * Bytes) + 3); + assert(Padding >= 0 && "Instrumentation map entry > 4 * Word Size"); + Out->EmitZeros(Padding); +} + +void AsmPrinter::emitXRayTable() { + if (Sleds.empty()) + return; + + auto PrevSection = OutStreamer->getCurrentSectionOnly(); + const Function &F = MF->getFunction(); + MCSection *InstMap = nullptr; + MCSection *FnSledIndex = nullptr; + if (MF->getSubtarget().getTargetTriple().isOSBinFormatELF()) { + auto Associated = dyn_cast<MCSymbolELF>(CurrentFnSym); + assert(Associated != nullptr); + auto Flags = ELF::SHF_WRITE | ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER; + std::string GroupName; + if (F.hasComdat()) { + Flags |= ELF::SHF_GROUP; + GroupName = F.getComdat()->getName(); + } + + auto UniqueID = ++XRayFnUniqueID; + InstMap = + OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS, Flags, 0, + GroupName, UniqueID, Associated); + FnSledIndex = + OutContext.getELFSection("xray_fn_idx", ELF::SHT_PROGBITS, Flags, 0, + GroupName, UniqueID, Associated); + } else if (MF->getSubtarget().getTargetTriple().isOSBinFormatMachO()) { + InstMap = OutContext.getMachOSection("__DATA", "xray_instr_map", 0, + SectionKind::getReadOnlyWithRel()); + FnSledIndex = OutContext.getMachOSection("__DATA", "xray_fn_idx", 0, + SectionKind::getReadOnlyWithRel()); + } else { + llvm_unreachable("Unsupported target"); + } + + auto WordSizeBytes = MAI->getCodePointerSize(); + + // Now we switch to the instrumentation map section. Because this is done + // per-function, we are able to create an index entry that will represent the + // range of sleds associated with a function. + MCSymbol *SledsStart = OutContext.createTempSymbol("xray_sleds_start", true); + OutStreamer->SwitchSection(InstMap); + OutStreamer->EmitLabel(SledsStart); + for (const auto &Sled : Sleds) + Sled.emit(WordSizeBytes, OutStreamer.get(), CurrentFnSym); + MCSymbol *SledsEnd = OutContext.createTempSymbol("xray_sleds_end", true); + OutStreamer->EmitLabel(SledsEnd); + + // We then emit a single entry in the index per function. We use the symbols + // that bound the instrumentation map as the range for a specific function. + // Each entry here will be 2 * word size aligned, as we're writing down two + // pointers. This should work for both 32-bit and 64-bit platforms. + OutStreamer->SwitchSection(FnSledIndex); + OutStreamer->EmitCodeAlignment(2 * WordSizeBytes); + OutStreamer->EmitSymbolValue(SledsStart, WordSizeBytes, false); + OutStreamer->EmitSymbolValue(SledsEnd, WordSizeBytes, false); + OutStreamer->SwitchSection(PrevSection); + Sleds.clear(); +} + +void AsmPrinter::recordSled(MCSymbol *Sled, const MachineInstr &MI, + SledKind Kind, uint8_t Version) { + const Function &F = MI.getMF()->getFunction(); + auto Attr = F.getFnAttribute("function-instrument"); + bool LogArgs = F.hasFnAttribute("xray-log-args"); + bool AlwaysInstrument = + Attr.isStringAttribute() && Attr.getValueAsString() == "xray-always"; + if (Kind == SledKind::FUNCTION_ENTER && LogArgs) + Kind = SledKind::LOG_ARGS_ENTER; + Sleds.emplace_back(XRayFunctionEntry{Sled, CurrentFnSym, Kind, + AlwaysInstrument, &F, Version}); +} + +uint16_t AsmPrinter::getDwarfVersion() const { + return OutStreamer->getContext().getDwarfVersion(); +} + +void AsmPrinter::setDwarfVersion(uint16_t Version) { + OutStreamer->getContext().setDwarfVersion(Version); +} |