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AArch64AsmPrinter.cpp
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//===- AArch64AsmPrinter.cpp - AArch64 LLVM assembly writer ---------------===//
//
// 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 contains a printer that converts from our internal representation
// of machine-dependent LLVM code to the AArch64 assembly language.
//
//===----------------------------------------------------------------------===//
#include "AArch64.h"
#include "AArch64MCInstLower.h"
#include "AArch64MachineFunctionInfo.h"
#include "AArch64RegisterInfo.h"
#include "AArch64Subtarget.h"
#include "AArch64TargetObjectFile.h"
#include "MCTargetDesc/AArch64AddressingModes.h"
#include "MCTargetDesc/AArch64InstPrinter.h"
#include "MCTargetDesc/AArch64MCExpr.h"
#include "MCTargetDesc/AArch64MCTargetDesc.h"
#include "MCTargetDesc/AArch64TargetStreamer.h"
#include "TargetInfo/AArch64TargetInfo.h"
#include "Utils/AArch64BaseInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/FaultMaps.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/StackMaps.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstBuilder.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Instrumentation/HWAddressSanitizer.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <map>
#include <memory>
using namespace llvm;
#define DEBUG_TYPE "asm-printer"
namespace {
class AArch64AsmPrinter : public AsmPrinter {
AArch64MCInstLower MCInstLowering;
StackMaps SM;
FaultMaps FM;
const AArch64Subtarget *STI;
public:
AArch64AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
: AsmPrinter(TM, std::move(Streamer)), MCInstLowering(OutContext, *this),
SM(*this), FM(*this) {}
StringRef getPassName() const override { return "AArch64 Assembly Printer"; }
/// Wrapper for MCInstLowering.lowerOperand() for the
/// tblgen'erated pseudo lowering.
bool lowerOperand(const MachineOperand &MO, MCOperand &MCOp) const {
return MCInstLowering.lowerOperand(MO, MCOp);
}
void emitStartOfAsmFile(Module &M) override;
void emitJumpTableInfo() override;
void emitFunctionEntryLabel() override;
void LowerJumpTableDest(MCStreamer &OutStreamer, const MachineInstr &MI);
void LowerSTACKMAP(MCStreamer &OutStreamer, StackMaps &SM,
const MachineInstr &MI);
void LowerPATCHPOINT(MCStreamer &OutStreamer, StackMaps &SM,
const MachineInstr &MI);
void LowerSTATEPOINT(MCStreamer &OutStreamer, StackMaps &SM,
const MachineInstr &MI);
void LowerFAULTING_OP(const MachineInstr &MI);
void LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI);
void LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr &MI);
void LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI);
typedef std::tuple<unsigned, bool, uint32_t> HwasanMemaccessTuple;
std::map<HwasanMemaccessTuple, MCSymbol *> HwasanMemaccessSymbols;
void LowerHWASAN_CHECK_MEMACCESS(const MachineInstr &MI);
void EmitHwasanMemaccessSymbols(Module &M);
void EmitSled(const MachineInstr &MI, SledKind Kind);
/// tblgen'erated driver function for lowering simple MI->MC
/// pseudo instructions.
bool emitPseudoExpansionLowering(MCStreamer &OutStreamer,
const MachineInstr *MI);
void emitInstruction(const MachineInstr *MI) override;
void emitFunctionHeaderComment() override;
void getAnalysisUsage(AnalysisUsage &AU) const override {
AsmPrinter::getAnalysisUsage(AU);
AU.setPreservesAll();
}
bool runOnMachineFunction(MachineFunction &MF) override {
AArch64FI = MF.getInfo<AArch64FunctionInfo>();
STI = static_cast<const AArch64Subtarget*>(&MF.getSubtarget());
SetupMachineFunction(MF);
if (STI->isTargetCOFF()) {
bool Internal = MF.getFunction().hasInternalLinkage();
COFF::SymbolStorageClass Scl = Internal ? COFF::IMAGE_SYM_CLASS_STATIC
: COFF::IMAGE_SYM_CLASS_EXTERNAL;
int Type =
COFF::IMAGE_SYM_DTYPE_FUNCTION << COFF::SCT_COMPLEX_TYPE_SHIFT;
OutStreamer->BeginCOFFSymbolDef(CurrentFnSym);
OutStreamer->EmitCOFFSymbolStorageClass(Scl);
OutStreamer->EmitCOFFSymbolType(Type);
OutStreamer->EndCOFFSymbolDef();
}
// Emit the rest of the function body.
emitFunctionBody();
// Emit the XRay table for this function.
emitXRayTable();
// We didn't modify anything.
return false;
}
private:
void printOperand(const MachineInstr *MI, unsigned OpNum, raw_ostream &O);
bool printAsmMRegister(const MachineOperand &MO, char Mode, raw_ostream &O);
bool printAsmRegInClass(const MachineOperand &MO,
const TargetRegisterClass *RC, unsigned AltName,
raw_ostream &O);
bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
const char *ExtraCode, raw_ostream &O) override;
bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNum,
const char *ExtraCode, raw_ostream &O) override;
void PrintDebugValueComment(const MachineInstr *MI, raw_ostream &OS);
void emitFunctionBodyEnd() override;
MCSymbol *GetCPISymbol(unsigned CPID) const override;
void emitEndOfAsmFile(Module &M) override;
AArch64FunctionInfo *AArch64FI = nullptr;
/// Emit the LOHs contained in AArch64FI.
void EmitLOHs();
/// Emit instruction to set float register to zero.
void EmitFMov0(const MachineInstr &MI);
using MInstToMCSymbol = std::map<const MachineInstr *, MCSymbol *>;
MInstToMCSymbol LOHInstToLabel;
};
} // end anonymous namespace
void AArch64AsmPrinter::emitStartOfAsmFile(Module &M) {
const Triple &TT = TM.getTargetTriple();
if (TT.isOSBinFormatCOFF()) {
// Emit an absolute @feat.00 symbol. This appears to be some kind of
// compiler features bitfield read by link.exe.
MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
OutStreamer->BeginCOFFSymbolDef(S);
OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
OutStreamer->EndCOFFSymbolDef();
int64_t Feat00Flags = 0;
if (M.getModuleFlag("cfguard")) {
Feat00Flags |= 0x800; // Object is CFG-aware.
}
if (M.getModuleFlag("ehcontguard")) {
Feat00Flags |= 0x4000; // Object also has EHCont.
}
OutStreamer->emitSymbolAttribute(S, MCSA_Global);
OutStreamer->emitAssignment(
S, MCConstantExpr::create(Feat00Flags, MMI->getContext()));
}
if (!TT.isOSBinFormatELF())
return;
// Assemble feature flags that may require creation of a note section.
unsigned Flags = 0;
if (const auto *BTE = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("branch-target-enforcement")))
if (BTE->getZExtValue())
Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
if (const auto *Sign = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("sign-return-address")))
if (Sign->getZExtValue())
Flags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
if (Flags == 0)
return;
// Emit a .note.gnu.property section with the flags.
if (auto *TS = static_cast<AArch64TargetStreamer *>(
OutStreamer->getTargetStreamer()))
TS->emitNoteSection(Flags);
}
void AArch64AsmPrinter::emitFunctionHeaderComment() {
const AArch64FunctionInfo *FI = MF->getInfo<AArch64FunctionInfo>();
Optional<std::string> OutlinerString = FI->getOutliningStyle();
if (OutlinerString != None)
OutStreamer->GetCommentOS() << ' ' << OutlinerString;
}
void AArch64AsmPrinter::LowerPATCHABLE_FUNCTION_ENTER(const MachineInstr &MI)
{
const Function &F = MF->getFunction();
if (F.hasFnAttribute("patchable-function-entry")) {
unsigned Num;
if (F.getFnAttribute("patchable-function-entry")
.getValueAsString()
.getAsInteger(10, Num))
return;
emitNops(Num);
return;
}
EmitSled(MI, SledKind::FUNCTION_ENTER);
}
void AArch64AsmPrinter::LowerPATCHABLE_FUNCTION_EXIT(const MachineInstr &MI)
{
EmitSled(MI, SledKind::FUNCTION_EXIT);
}
void AArch64AsmPrinter::LowerPATCHABLE_TAIL_CALL(const MachineInstr &MI)
{
EmitSled(MI, SledKind::TAIL_CALL);
}
void AArch64AsmPrinter::EmitSled(const MachineInstr &MI, SledKind Kind)
{
static const int8_t NoopsInSledCount = 7;
// We want to emit the following pattern:
//
// .Lxray_sled_N:
// ALIGN
// B #32
// ; 7 NOP instructions (28 bytes)
// .tmpN
//
// We need the 28 bytes (7 instructions) because at runtime, we'd be patching
// over the full 32 bytes (8 instructions) with the following pattern:
//
// STP X0, X30, [SP, #-16]! ; push X0 and the link register to the stack
// LDR W0, #12 ; W0 := function ID
// LDR X16,#12 ; X16 := addr of __xray_FunctionEntry or __xray_FunctionExit
// BLR X16 ; call the tracing trampoline
// ;DATA: 32 bits of function ID
// ;DATA: lower 32 bits of the address of the trampoline
// ;DATA: higher 32 bits of the address of the trampoline
// LDP X0, X30, [SP], #16 ; pop X0 and the link register from the stack
//
OutStreamer->emitCodeAlignment(4);
auto CurSled = OutContext.createTempSymbol("xray_sled_", true);
OutStreamer->emitLabel(CurSled);
auto Target = OutContext.createTempSymbol();
// Emit "B #32" instruction, which jumps over the next 28 bytes.
// The operand has to be the number of 4-byte instructions to jump over,
// including the current instruction.
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::B).addImm(8));
for (int8_t I = 0; I < NoopsInSledCount; I++)
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::HINT).addImm(0));
OutStreamer->emitLabel(Target);
recordSled(CurSled, MI, Kind, 2);
}
void AArch64AsmPrinter::LowerHWASAN_CHECK_MEMACCESS(const MachineInstr &MI) {
Register Reg = MI.getOperand(0).getReg();
bool IsShort =
MI.getOpcode() == AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES;
uint32_t AccessInfo = MI.getOperand(1).getImm();
MCSymbol *&Sym =
HwasanMemaccessSymbols[HwasanMemaccessTuple(Reg, IsShort, AccessInfo)];
if (!Sym) {
// FIXME: Make this work on non-ELF.
if (!TM.getTargetTriple().isOSBinFormatELF())
report_fatal_error("llvm.hwasan.check.memaccess only supported on ELF");
std::string SymName = "__hwasan_check_x" + utostr(Reg - AArch64::X0) + "_" +
utostr(AccessInfo);
if (IsShort)
SymName += "_short_v2";
Sym = OutContext.getOrCreateSymbol(SymName);
}
EmitToStreamer(*OutStreamer,
MCInstBuilder(AArch64::BL)
.addExpr(MCSymbolRefExpr::create(Sym, OutContext)));
}
void AArch64AsmPrinter::EmitHwasanMemaccessSymbols(Module &M) {
if (HwasanMemaccessSymbols.empty())
return;
const Triple &TT = TM.getTargetTriple();
assert(TT.isOSBinFormatELF());
std::unique_ptr<MCSubtargetInfo> STI(
TM.getTarget().createMCSubtargetInfo(TT.str(), "", ""));
assert(STI && "Unable to create subtarget info");
MCSymbol *HwasanTagMismatchV1Sym =
OutContext.getOrCreateSymbol("__hwasan_tag_mismatch");
MCSymbol *HwasanTagMismatchV2Sym =
OutContext.getOrCreateSymbol("__hwasan_tag_mismatch_v2");
const MCSymbolRefExpr *HwasanTagMismatchV1Ref =
MCSymbolRefExpr::create(HwasanTagMismatchV1Sym, OutContext);
const MCSymbolRefExpr *HwasanTagMismatchV2Ref =
MCSymbolRefExpr::create(HwasanTagMismatchV2Sym, OutContext);
for (auto &P : HwasanMemaccessSymbols) {
unsigned Reg = std::get<0>(P.first);
bool IsShort = std::get<1>(P.first);
uint32_t AccessInfo = std::get<2>(P.first);
const MCSymbolRefExpr *HwasanTagMismatchRef =
IsShort ? HwasanTagMismatchV2Ref : HwasanTagMismatchV1Ref;
MCSymbol *Sym = P.second;
bool HasMatchAllTag =
(AccessInfo >> HWASanAccessInfo::HasMatchAllShift) & 1;
uint8_t MatchAllTag =
(AccessInfo >> HWASanAccessInfo::MatchAllShift) & 0xff;
unsigned Size =
1 << ((AccessInfo >> HWASanAccessInfo::AccessSizeShift) & 0xf);
bool CompileKernel =
(AccessInfo >> HWASanAccessInfo::CompileKernelShift) & 1;
OutStreamer->SwitchSection(OutContext.getELFSection(
".text.hot", ELF::SHT_PROGBITS,
ELF::SHF_EXECINSTR | ELF::SHF_ALLOC | ELF::SHF_GROUP, 0,
Sym->getName(), /*IsComdat=*/true));
OutStreamer->emitSymbolAttribute(Sym, MCSA_ELF_TypeFunction);
OutStreamer->emitSymbolAttribute(Sym, MCSA_Weak);
OutStreamer->emitSymbolAttribute(Sym, MCSA_Hidden);
OutStreamer->emitLabel(Sym);
OutStreamer->emitInstruction(MCInstBuilder(AArch64::SBFMXri)
.addReg(AArch64::X16)
.addReg(Reg)
.addImm(4)
.addImm(55),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::LDRBBroX)
.addReg(AArch64::W16)
.addReg(IsShort ? AArch64::X20 : AArch64::X9)
.addReg(AArch64::X16)
.addImm(0)
.addImm(0),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::SUBSXrs)
.addReg(AArch64::XZR)
.addReg(AArch64::X16)
.addReg(Reg)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSR, 56)),
*STI);
MCSymbol *HandleMismatchOrPartialSym = OutContext.createTempSymbol();
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::NE)
.addExpr(MCSymbolRefExpr::create(HandleMismatchOrPartialSym,
OutContext)),
*STI);
MCSymbol *ReturnSym = OutContext.createTempSymbol();
OutStreamer->emitLabel(ReturnSym);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::RET).addReg(AArch64::LR), *STI);
OutStreamer->emitLabel(HandleMismatchOrPartialSym);
if (HasMatchAllTag) {
OutStreamer->emitInstruction(MCInstBuilder(AArch64::UBFMXri)
.addReg(AArch64::X16)
.addReg(Reg)
.addImm(56)
.addImm(63),
*STI);
OutStreamer->emitInstruction(MCInstBuilder(AArch64::SUBSXri)
.addReg(AArch64::XZR)
.addReg(AArch64::X16)
.addImm(MatchAllTag)
.addImm(0),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::EQ)
.addExpr(MCSymbolRefExpr::create(ReturnSym, OutContext)),
*STI);
}
if (IsShort) {
OutStreamer->emitInstruction(MCInstBuilder(AArch64::SUBSWri)
.addReg(AArch64::WZR)
.addReg(AArch64::W16)
.addImm(15)
.addImm(0),
*STI);
MCSymbol *HandleMismatchSym = OutContext.createTempSymbol();
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::HI)
.addExpr(MCSymbolRefExpr::create(HandleMismatchSym, OutContext)),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::ANDXri)
.addReg(AArch64::X17)
.addReg(Reg)
.addImm(AArch64_AM::encodeLogicalImmediate(0xf, 64)),
*STI);
if (Size != 1)
OutStreamer->emitInstruction(MCInstBuilder(AArch64::ADDXri)
.addReg(AArch64::X17)
.addReg(AArch64::X17)
.addImm(Size - 1)
.addImm(0),
*STI);
OutStreamer->emitInstruction(MCInstBuilder(AArch64::SUBSWrs)
.addReg(AArch64::WZR)
.addReg(AArch64::W16)
.addReg(AArch64::W17)
.addImm(0),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::LS)
.addExpr(MCSymbolRefExpr::create(HandleMismatchSym, OutContext)),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::ORRXri)
.addReg(AArch64::X16)
.addReg(Reg)
.addImm(AArch64_AM::encodeLogicalImmediate(0xf, 64)),
*STI);
OutStreamer->emitInstruction(MCInstBuilder(AArch64::LDRBBui)
.addReg(AArch64::W16)
.addReg(AArch64::X16)
.addImm(0),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::SUBSXrs)
.addReg(AArch64::XZR)
.addReg(AArch64::X16)
.addReg(Reg)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSR, 56)),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::EQ)
.addExpr(MCSymbolRefExpr::create(ReturnSym, OutContext)),
*STI);
OutStreamer->emitLabel(HandleMismatchSym);
}
OutStreamer->emitInstruction(MCInstBuilder(AArch64::STPXpre)
.addReg(AArch64::SP)
.addReg(AArch64::X0)
.addReg(AArch64::X1)
.addReg(AArch64::SP)
.addImm(-32),
*STI);
OutStreamer->emitInstruction(MCInstBuilder(AArch64::STPXi)
.addReg(AArch64::FP)
.addReg(AArch64::LR)
.addReg(AArch64::SP)
.addImm(29),
*STI);
if (Reg != AArch64::X0)
OutStreamer->emitInstruction(MCInstBuilder(AArch64::ORRXrs)
.addReg(AArch64::X0)
.addReg(AArch64::XZR)
.addReg(Reg)
.addImm(0),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::MOVZXi)
.addReg(AArch64::X1)
.addImm(AccessInfo & HWASanAccessInfo::RuntimeMask)
.addImm(0),
*STI);
if (CompileKernel) {
// The Linux kernel's dynamic loader doesn't support GOT relative
// relocations, but it doesn't support late binding either, so just call
// the function directly.
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::B).addExpr(HwasanTagMismatchRef), *STI);
} else {
// Intentionally load the GOT entry and branch to it, rather than possibly
// late binding the function, which may clobber the registers before we
// have a chance to save them.
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::ADRP)
.addReg(AArch64::X16)
.addExpr(AArch64MCExpr::create(
HwasanTagMismatchRef, AArch64MCExpr::VariantKind::VK_GOT_PAGE,
OutContext)),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::LDRXui)
.addReg(AArch64::X16)
.addReg(AArch64::X16)
.addExpr(AArch64MCExpr::create(
HwasanTagMismatchRef, AArch64MCExpr::VariantKind::VK_GOT_LO12,
OutContext)),
*STI);
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::BR).addReg(AArch64::X16), *STI);
}
}
}
void AArch64AsmPrinter::emitEndOfAsmFile(Module &M) {
EmitHwasanMemaccessSymbols(M);
const Triple &TT = TM.getTargetTriple();
if (TT.isOSBinFormatMachO()) {
// Funny Darwin hack: This flag tells the linker that no global symbols
// contain code that falls through to other global symbols (e.g. the obvious
// implementation of multiple entry points). If this doesn't occur, the
// linker can safely perform dead code stripping. Since LLVM never
// generates code that does this, it is always safe to set.
OutStreamer->emitAssemblerFlag(MCAF_SubsectionsViaSymbols);
}
// Emit stack and fault map information.
emitStackMaps(SM);
FM.serializeToFaultMapSection();
}
void AArch64AsmPrinter::EmitLOHs() {
SmallVector<MCSymbol *, 3> MCArgs;
for (const auto &D : AArch64FI->getLOHContainer()) {
for (const MachineInstr *MI : D.getArgs()) {
MInstToMCSymbol::iterator LabelIt = LOHInstToLabel.find(MI);
assert(LabelIt != LOHInstToLabel.end() &&
"Label hasn't been inserted for LOH related instruction");
MCArgs.push_back(LabelIt->second);
}
OutStreamer->emitLOHDirective(D.getKind(), MCArgs);
MCArgs.clear();
}
}
void AArch64AsmPrinter::emitFunctionBodyEnd() {
if (!AArch64FI->getLOHRelated().empty())
EmitLOHs();
}
/// GetCPISymbol - Return the symbol for the specified constant pool entry.
MCSymbol *AArch64AsmPrinter::GetCPISymbol(unsigned CPID) const {
// Darwin uses a linker-private symbol name for constant-pools (to
// avoid addends on the relocation?), ELF has no such concept and
// uses a normal private symbol.
if (!getDataLayout().getLinkerPrivateGlobalPrefix().empty())
return OutContext.getOrCreateSymbol(
Twine(getDataLayout().getLinkerPrivateGlobalPrefix()) + "CPI" +
Twine(getFunctionNumber()) + "_" + Twine(CPID));
return AsmPrinter::GetCPISymbol(CPID);
}
void AArch64AsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNum,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(OpNum);
switch (MO.getType()) {
default:
llvm_unreachable("<unknown operand type>");
case MachineOperand::MO_Register: {
Register Reg = MO.getReg();
assert(Register::isPhysicalRegister(Reg));
assert(!MO.getSubReg() && "Subregs should be eliminated!");
O << AArch64InstPrinter::getRegisterName(Reg);
break;
}
case MachineOperand::MO_Immediate: {
O << MO.getImm();
break;
}
case MachineOperand::MO_GlobalAddress: {
PrintSymbolOperand(MO, O);
break;
}
case MachineOperand::MO_BlockAddress: {
MCSymbol *Sym = GetBlockAddressSymbol(MO.getBlockAddress());
Sym->print(O, MAI);
break;
}
}
}
bool AArch64AsmPrinter::printAsmMRegister(const MachineOperand &MO, char Mode,
raw_ostream &O) {
Register Reg = MO.getReg();
switch (Mode) {
default:
return true; // Unknown mode.
case 'w':
Reg = getWRegFromXReg(Reg);
break;
case 'x':
Reg = getXRegFromWReg(Reg);
break;
}
O << AArch64InstPrinter::getRegisterName(Reg);
return false;
}
// Prints the register in MO using class RC using the offset in the
// new register class. This should not be used for cross class
// printing.
bool AArch64AsmPrinter::printAsmRegInClass(const MachineOperand &MO,
const TargetRegisterClass *RC,
unsigned AltName, raw_ostream &O) {
assert(MO.isReg() && "Should only get here with a register!");
const TargetRegisterInfo *RI = STI->getRegisterInfo();
Register Reg = MO.getReg();
unsigned RegToPrint = RC->getRegister(RI->getEncodingValue(Reg));
if (!RI->regsOverlap(RegToPrint, Reg))
return true;
O << AArch64InstPrinter::getRegisterName(RegToPrint, AltName);
return false;
}
bool AArch64AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
const char *ExtraCode, raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(OpNum);
// First try the generic code, which knows about modifiers like 'c' and 'n'.
if (!AsmPrinter::PrintAsmOperand(MI, OpNum, ExtraCode, O))
return false;
// Does this asm operand have a single letter operand modifier?
if (ExtraCode && ExtraCode[0]) {
if (ExtraCode[1] != 0)
return true; // Unknown modifier.
switch (ExtraCode[0]) {
default:
return true; // Unknown modifier.
case 'w': // Print W register
case 'x': // Print X register
if (MO.isReg())
return printAsmMRegister(MO, ExtraCode[0], O);
if (MO.isImm() && MO.getImm() == 0) {
unsigned Reg = ExtraCode[0] == 'w' ? AArch64::WZR : AArch64::XZR;
O << AArch64InstPrinter::getRegisterName(Reg);
return false;
}
printOperand(MI, OpNum, O);
return false;
case 'b': // Print B register.
case 'h': // Print H register.
case 's': // Print S register.
case 'd': // Print D register.
case 'q': // Print Q register.
case 'z': // Print Z register.
if (MO.isReg()) {
const TargetRegisterClass *RC;
switch (ExtraCode[0]) {
case 'b':
RC = &AArch64::FPR8RegClass;
break;
case 'h':
RC = &AArch64::FPR16RegClass;
break;
case 's':
RC = &AArch64::FPR32RegClass;
break;
case 'd':
RC = &AArch64::FPR64RegClass;
break;
case 'q':
RC = &AArch64::FPR128RegClass;
break;
case 'z':
RC = &AArch64::ZPRRegClass;
break;
default:
return true;
}
return printAsmRegInClass(MO, RC, AArch64::NoRegAltName, O);
}
printOperand(MI, OpNum, O);
return false;
}
}
// According to ARM, we should emit x and v registers unless we have a
// modifier.
if (MO.isReg()) {
Register Reg = MO.getReg();
// If this is a w or x register, print an x register.
if (AArch64::GPR32allRegClass.contains(Reg) ||
AArch64::GPR64allRegClass.contains(Reg))
return printAsmMRegister(MO, 'x', O);
unsigned AltName = AArch64::NoRegAltName;
const TargetRegisterClass *RegClass;
if (AArch64::ZPRRegClass.contains(Reg)) {
RegClass = &AArch64::ZPRRegClass;
} else if (AArch64::PPRRegClass.contains(Reg)) {
RegClass = &AArch64::PPRRegClass;
} else {
RegClass = &AArch64::FPR128RegClass;
AltName = AArch64::vreg;
}
// If this is a b, h, s, d, or q register, print it as a v register.
return printAsmRegInClass(MO, RegClass, AltName, O);
}
printOperand(MI, OpNum, O);
return false;
}
bool AArch64AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
unsigned OpNum,
const char *ExtraCode,
raw_ostream &O) {
if (ExtraCode && ExtraCode[0] && ExtraCode[0] != 'a')
return true; // Unknown modifier.
const MachineOperand &MO = MI->getOperand(OpNum);
assert(MO.isReg() && "unexpected inline asm memory operand");
O << "[" << AArch64InstPrinter::getRegisterName(MO.getReg()) << "]";
return false;
}
void AArch64AsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
raw_ostream &OS) {
unsigned NOps = MI->getNumOperands();
assert(NOps == 4);
OS << '\t' << MAI->getCommentString() << "DEBUG_VALUE: ";
// cast away const; DIetc do not take const operands for some reason.
OS << MI->getDebugVariable()->getName();
OS << " <- ";
// Frame address. Currently handles register +- offset only.
assert(MI->isIndirectDebugValue());
OS << '[';
for (unsigned I = 0, E = std::distance(MI->debug_operands().begin(),
MI->debug_operands().end());
I < E; ++I) {
if (I != 0)
OS << ", ";
printOperand(MI, I, OS);
}
OS << ']';
OS << "+";
printOperand(MI, NOps - 2, OS);
}
void AArch64AsmPrinter::emitJumpTableInfo() {
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
if (!MJTI) return;
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
if (JT.empty()) return;
const Function &F = MF->getFunction();
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
bool JTInDiffSection =
!STI->isTargetCOFF() ||
!TLOF.shouldPutJumpTableInFunctionSection(
MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
F);
if (JTInDiffSection) {
// Drop it in the readonly section.
MCSection *ReadOnlySec = TLOF.getSectionForJumpTable(F, TM);
OutStreamer->SwitchSection(ReadOnlySec);
}
auto AFI = MF->getInfo<AArch64FunctionInfo>();
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;
unsigned Size = AFI->getJumpTableEntrySize(JTI);
emitAlignment(Align(Size));
OutStreamer->emitLabel(GetJTISymbol(JTI));
const MCSymbol *BaseSym = AArch64FI->getJumpTableEntryPCRelSymbol(JTI);
const MCExpr *Base = MCSymbolRefExpr::create(BaseSym, OutContext);
for (auto *JTBB : JTBBs) {
const MCExpr *Value =
MCSymbolRefExpr::create(JTBB->getSymbol(), OutContext);
// Each entry is:
// .byte/.hword (LBB - Lbase)>>2
// or plain:
// .word LBB - Lbase
Value = MCBinaryExpr::createSub(Value, Base, OutContext);
if (Size != 4)
Value = MCBinaryExpr::createLShr(
Value, MCConstantExpr::create(2, OutContext), OutContext);
OutStreamer->emitValue(Value, Size);
}
}
}
void AArch64AsmPrinter::emitFunctionEntryLabel() {
if (MF->getFunction().getCallingConv() == CallingConv::AArch64_VectorCall ||
MF->getFunction().getCallingConv() ==
CallingConv::AArch64_SVE_VectorCall ||
STI->getRegisterInfo()->hasSVEArgsOrReturn(MF)) {
auto *TS =
static_cast<AArch64TargetStreamer *>(OutStreamer->getTargetStreamer());
TS->emitDirectiveVariantPCS(CurrentFnSym);
}
return AsmPrinter::emitFunctionEntryLabel();
}
/// Small jump tables contain an unsigned byte or half, representing the offset
/// from the lowest-addressed possible destination to the desired basic
/// block. Since all instructions are 4-byte aligned, this is further compressed
/// by counting in instructions rather than bytes (i.e. divided by 4). So, to
/// materialize the correct destination we need:
///
/// adr xDest, .LBB0_0
/// ldrb wScratch, [xTable, xEntry] (with "lsl #1" for ldrh).
/// add xDest, xDest, xScratch (with "lsl #2" for smaller entries)
void AArch64AsmPrinter::LowerJumpTableDest(llvm::MCStreamer &OutStreamer,
const llvm::MachineInstr &MI) {
Register DestReg = MI.getOperand(0).getReg();
Register ScratchReg = MI.getOperand(1).getReg();
Register ScratchRegW =
STI->getRegisterInfo()->getSubReg(ScratchReg, AArch64::sub_32);
Register TableReg = MI.getOperand(2).getReg();
Register EntryReg = MI.getOperand(3).getReg();
int JTIdx = MI.getOperand(4).getIndex();
int Size = AArch64FI->getJumpTableEntrySize(JTIdx);
// This has to be first because the compression pass based its reachability
// calculations on the start of the JumpTableDest instruction.
auto Label =
MF->getInfo<AArch64FunctionInfo>()->getJumpTableEntryPCRelSymbol(JTIdx);
// If we don't already have a symbol to use as the base, use the ADR
// instruction itself.
if (!Label) {
Label = MF->getContext().createTempSymbol();
AArch64FI->setJumpTableEntryInfo(JTIdx, Size, Label);
OutStreamer.emitLabel(Label);
}
auto LabelExpr = MCSymbolRefExpr::create(Label, MF->getContext());
EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::ADR)
.addReg(DestReg)
.addExpr(LabelExpr));
// Load the number of instruction-steps to offset from the label.
unsigned LdrOpcode;
switch (Size) {
case 1: LdrOpcode = AArch64::LDRBBroX; break;
case 2: LdrOpcode = AArch64::LDRHHroX; break;
case 4: LdrOpcode = AArch64::LDRSWroX; break;
default:
llvm_unreachable("Unknown jump table size");
}
EmitToStreamer(OutStreamer, MCInstBuilder(LdrOpcode)
.addReg(Size == 4 ? ScratchReg : ScratchRegW)
.addReg(TableReg)
.addReg(EntryReg)
.addImm(0)
.addImm(Size == 1 ? 0 : 1));
// Add to the already materialized base label address, multiplying by 4 if
// compressed.
EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::ADDXrs)
.addReg(DestReg)
.addReg(DestReg)
.addReg(ScratchReg)
.addImm(Size == 4 ? 0 : 2));
}
void AArch64AsmPrinter::LowerSTACKMAP(MCStreamer &OutStreamer, StackMaps &SM,
const MachineInstr &MI) {
unsigned NumNOPBytes = StackMapOpers(&MI).getNumPatchBytes();
auto &Ctx = OutStreamer.getContext();
MCSymbol *MILabel = Ctx.createTempSymbol();
OutStreamer.emitLabel(MILabel);
SM.recordStackMap(*MILabel, MI);
assert(NumNOPBytes % 4 == 0 && "Invalid number of NOP bytes requested!");
// Scan ahead to trim the shadow.
const MachineBasicBlock &MBB = *MI.getParent();
MachineBasicBlock::const_iterator MII(MI);
++MII;
while (NumNOPBytes > 0) {
if (MII == MBB.end() || MII->isCall() ||
MII->getOpcode() == AArch64::DBG_VALUE ||
MII->getOpcode() == TargetOpcode::PATCHPOINT ||
MII->getOpcode() == TargetOpcode::STACKMAP)
break;
++MII;
NumNOPBytes -= 4;
}
// Emit nops.
for (unsigned i = 0; i < NumNOPBytes; i += 4)
EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::HINT).addImm(0));
}
// Lower a patchpoint of the form:
// [<def>], <id>, <numBytes>, <target>, <numArgs>
void AArch64AsmPrinter::LowerPATCHPOINT(MCStreamer &OutStreamer, StackMaps &SM,
const MachineInstr &MI) {
auto &Ctx = OutStreamer.getContext();
MCSymbol *MILabel = Ctx.createTempSymbol();
OutStreamer.emitLabel(MILabel);
SM.recordPatchPoint(*MILabel, MI);
PatchPointOpers Opers(&MI);
int64_t CallTarget = Opers.getCallTarget().getImm();
unsigned EncodedBytes = 0;
if (CallTarget) {
assert((CallTarget & 0xFFFFFFFFFFFF) == CallTarget &&
"High 16 bits of call target should be zero.");
Register ScratchReg = MI.getOperand(Opers.getNextScratchIdx()).getReg();
EncodedBytes = 16;
// Materialize the jump address:
EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::MOVZXi)
.addReg(ScratchReg)
.addImm((CallTarget >> 32) & 0xFFFF)
.addImm(32));
EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::MOVKXi)
.addReg(ScratchReg)
.addReg(ScratchReg)
.addImm((CallTarget >> 16) & 0xFFFF)
.addImm(16));
EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::MOVKXi)
.addReg(ScratchReg)
.addReg(ScratchReg)
.addImm(CallTarget & 0xFFFF)