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llvm-project/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
Abhay Kanhere e39d2822bc
[CodeGen][AArch64] ptrauth intrinsic to safely construct relative ptr (#142047) 
ptrauth intrinsic to safely construct relative ptr for swift coroutines.

A ptrauth intrinsic for swift co-routine support that allows creation of
signed pointer
 from offset stored at address relative to the pointer.

Following C-like pseudo code (ignoring keys,discriminators) explains its
operation:
      let rawptr = PACauth(inputptr);
return PACsign( rawptr + signextend64( *(int32*)(rawptr+addend) ))

What: Authenticate a signed pointer, load a 32bit value at offset
'addend' from pointer,
       add this value to pointer, sign this new pointer.
 builtin: __builtin_ptrauth_auth_load_relative_and_sign
 intrinsic: ptrauth_auth_resign_load_relative
2026-02-03 18:03:37 +01:00

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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/AArch64MCAsmInfo.h"
#include "MCTargetDesc/AArch64MCTargetDesc.h"
#include "MCTargetDesc/AArch64TargetStreamer.h"
#include "TargetInfo/AArch64TargetInfo.h"
#include "Utils/AArch64BaseInfo.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/BinaryFormat/MachO.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/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstBuilder.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/TargetParser/Triple.h"
#include "llvm/Transforms/Instrumentation/HWAddressSanitizer.h"
#include <cassert>
#include <cstdint>
#include <map>
#include <memory>
using namespace llvm;
#define DEBUG_TYPE "AArch64AsmPrinter"
// Doesn't count FPR128 ZCZ instructions which are handled
// by TableGen pattern matching
STATISTIC(NumZCZeroingInstrsFPR,
"Number of zero-cycle FPR zeroing instructions expanded from "
"canonical pseudo instructions");
enum PtrauthCheckMode { Default, Unchecked, Poison, Trap };
static cl::opt<PtrauthCheckMode> PtrauthAuthChecks(
"aarch64-ptrauth-auth-checks", cl::Hidden,
cl::values(clEnumValN(Unchecked, "none", "don't test for failure"),
clEnumValN(Poison, "poison", "poison on failure"),
clEnumValN(Trap, "trap", "trap on failure")),
cl::desc("Check pointer authentication auth/resign failures"),
cl::init(Default));
namespace {
class AArch64AsmPrinter : public AsmPrinter {
AArch64MCInstLower MCInstLowering;
FaultMaps FM;
const AArch64Subtarget *STI;
bool ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags = false;
#ifndef NDEBUG
unsigned InstsEmitted;
#endif
bool EnableImportCallOptimization = false;
MapVector<MCSection *, std::vector<std::pair<MCSymbol *, MCSymbol *>>>
SectionToImportedFunctionCalls;
unsigned PAuthIFuncNextUniqueID = 1;
public:
static char ID;
AArch64AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
: AsmPrinter(TM, std::move(Streamer), ID),
MCInstLowering(OutContext, *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);
}
const MCExpr *lowerConstantPtrAuth(const ConstantPtrAuth &CPA) override;
const MCExpr *lowerBlockAddressConstant(const BlockAddress &BA) override;
void emitStartOfAsmFile(Module &M) override;
void emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
ArrayRef<unsigned> JumpTableIndices) override;
std::tuple<const MCSymbol *, uint64_t, const MCSymbol *,
codeview::JumpTableEntrySize>
getCodeViewJumpTableInfo(int JTI, const MachineInstr *BranchInstr,
const MCSymbol *BranchLabel) const override;
void emitFunctionEntryLabel() override;
void emitXXStructor(const DataLayout &DL, const Constant *CV) override;
void LowerJumpTableDest(MCStreamer &OutStreamer, const MachineInstr &MI);
void LowerHardenedBRJumpTable(const MachineInstr &MI);
void LowerMOPS(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);
void LowerPATCHABLE_EVENT_CALL(const MachineInstr &MI, bool Typed);
typedef std::tuple<unsigned, bool, uint32_t, bool, uint64_t>
HwasanMemaccessTuple;
std::map<HwasanMemaccessTuple, MCSymbol *> HwasanMemaccessSymbols;
void LowerKCFI_CHECK(const MachineInstr &MI);
void LowerHWASAN_CHECK_MEMACCESS(const MachineInstr &MI);
void emitHwasanMemaccessSymbols(Module &M);
void emitSled(const MachineInstr &MI, SledKind Kind);
// Returns whether Reg may be used to store sensitive temporary values when
// expanding PtrAuth pseudos. Some OSes may take extra care to protect a
// small subset of GPRs on context switches - use these registers then.
//
// If there are no preferred registers, returns true for any Reg.
bool isPtrauthRegSafe(Register Reg) const {
if (STI->isX16X17Safer())
return Reg == AArch64::X16 || Reg == AArch64::X17;
return true;
}
// Emit the sequence for BRA/BLRA (authenticate + branch/call).
void emitPtrauthBranch(const MachineInstr *MI);
void emitPtrauthCheckAuthenticatedValue(Register TestedReg,
Register ScratchReg,
AArch64PACKey::ID Key,
AArch64PAuth::AuthCheckMethod Method,
const MCSymbol *OnFailure = nullptr);
// Check authenticated LR before tail calling.
void emitPtrauthTailCallHardening(const MachineInstr *TC);
struct PtrAuthSchema {
PtrAuthSchema(AArch64PACKey::ID Key, uint64_t IntDisc,
const MachineOperand &AddrDiscOp);
AArch64PACKey::ID Key;
uint64_t IntDisc;
Register AddrDisc;
bool AddrDiscIsKilled;
};
// Emit the sequence for AUT or AUTPAC. Addend if AUTRELLOADPAC
void emitPtrauthAuthResign(Register Pointer, Register Scratch,
PtrAuthSchema AuthSchema,
std::optional<PtrAuthSchema> SignSchema,
std::optional<uint64_t> Addend, Value *DS);
// Emit R_AARCH64_PATCHINST, the deactivation symbol relocation. Returns true
// if no instruction should be emitted because the deactivation symbol is
// defined in the current module so this function emitted a NOP instead.
bool emitDeactivationSymbolRelocation(Value *DS);
// Emit the sequence for PAC.
void emitPtrauthSign(const MachineInstr *MI);
// Emit the sequence to compute the discriminator.
//
// The Scratch register passed to this function must be safe, as returned by
// isPtrauthRegSafe(ScratchReg).
//
// The returned register is either ScratchReg, AddrDisc, or XZR. Furthermore,
// it is guaranteed to be safe (or XZR), with the only exception of
// passing-through an *unmodified* unsafe AddrDisc register.
//
// If the expanded pseudo is allowed to clobber AddrDisc register, setting
// MayClobberAddrDisc may save one MOV instruction, provided
// isPtrauthRegSafe(AddrDisc) is true:
//
// mov x17, x16
// movk x17, #1234, lsl #48
// ; x16 is not used anymore
//
// can be replaced by
//
// movk x16, #1234, lsl #48
Register emitPtrauthDiscriminator(uint64_t Disc, Register AddrDisc,
Register ScratchReg,
bool MayClobberAddrDisc = false);
// Emit the sequence for LOADauthptrstatic
void LowerLOADauthptrstatic(const MachineInstr &MI);
// Emit the sequence for LOADgotPAC/MOVaddrPAC (either GOT adrp-ldr or
// adrp-add followed by PAC sign)
void LowerMOVaddrPAC(const MachineInstr &MI);
// Emit the sequence for LOADgotAUTH (load signed pointer from signed ELF GOT
// and authenticate it with, if FPAC bit is not set, check+trap sequence after
// authenticating)
void LowerLOADgotAUTH(const MachineInstr &MI);
void emitAddImm(MCRegister Val, int64_t Addend, MCRegister Tmp);
void emitAddress(MCRegister Reg, const MCExpr *Expr, MCRegister Tmp,
bool DSOLocal, const MCSubtargetInfo &STI);
const MCExpr *emitPAuthRelocationAsIRelative(
const MCExpr *Target, uint64_t Disc, AArch64PACKey::ID KeyID,
bool HasAddressDiversity, bool IsDSOLocal, const MCExpr *DSExpr);
/// tblgen'erated driver function for lowering simple MI->MC
/// pseudo instructions.
bool lowerPseudoInstExpansion(const MachineInstr *MI, MCInst &Inst);
// Emit Build Attributes
void emitAttributes(unsigned Flags, uint64_t PAuthABIPlatform,
uint64_t PAuthABIVersion, AArch64TargetStreamer *TS);
// Emit expansion of Compare-and-branch pseudo instructions
void emitCBPseudoExpansion(const MachineInstr *MI);
void EmitToStreamer(MCStreamer &S, const MCInst &Inst);
void EmitToStreamer(const MCInst &Inst) {
EmitToStreamer(*OutStreamer, Inst);
}
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 {
if (auto *PSIW = getAnalysisIfAvailable<ProfileSummaryInfoWrapperPass>())
PSI = &PSIW->getPSI();
if (auto *SDPIW =
getAnalysisIfAvailable<StaticDataProfileInfoWrapperPass>())
SDPI = &SDPIW->getStaticDataProfileInfo();
AArch64FI = MF.getInfo<AArch64FunctionInfo>();
STI = &MF.getSubtarget<AArch64Subtarget>();
SetupMachineFunction(MF);
if (STI->isTargetCOFF()) {
bool Local = MF.getFunction().hasLocalLinkage();
COFF::SymbolStorageClass Scl =
Local ? 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;
}
const MCExpr *lowerConstant(const Constant *CV,
const Constant *BaseCV = nullptr,
uint64_t Offset = 0) override;
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;
void emitGlobalAlias(const Module &M, const GlobalAlias &GA) override;
MCSymbol *GetCPISymbol(unsigned CPID) const override;
void emitEndOfAsmFile(Module &M) override;
AArch64FunctionInfo *AArch64FI = nullptr;
/// Emit the LOHs contained in AArch64FI.
void emitLOHs();
void emitMovXReg(Register Dest, Register Src);
void emitMOVZ(Register Dest, uint64_t Imm, unsigned Shift);
void emitMOVK(Register Dest, uint64_t Imm, unsigned Shift);
void emitAUT(AArch64PACKey::ID Key, Register Pointer, Register Disc);
void emitPAC(AArch64PACKey::ID Key, Register Pointer, Register Disc);
void emitBLRA(bool IsCall, AArch64PACKey::ID Key, Register Target,
Register Disc);
/// Emit instruction to set float register to zero.
void emitFMov0(const MachineInstr &MI);
void emitFMov0AsFMov(const MachineInstr &MI, Register DestReg);
using MInstToMCSymbol = std::map<const MachineInstr *, MCSymbol *>;
MInstToMCSymbol LOHInstToLabel;
bool shouldEmitWeakSwiftAsyncExtendedFramePointerFlags() const override {
return ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags;
}
const MCSubtargetInfo *getIFuncMCSubtargetInfo() const override {
assert(STI);
return STI;
}
void emitMachOIFuncStubBody(Module &M, const GlobalIFunc &GI,
MCSymbol *LazyPointer) override;
void emitMachOIFuncStubHelperBody(Module &M, const GlobalIFunc &GI,
MCSymbol *LazyPointer) override;
/// Checks if this instruction is part of a sequence that is eligle for import
/// call optimization and, if so, records it to be emitted in the import call
/// section.
void recordIfImportCall(const MachineInstr *BranchInst);
};
} // end anonymous namespace
void AArch64AsmPrinter::emitStartOfAsmFile(Module &M) {
const Triple &TT = TM.getTargetTriple();
if (TT.isOSBinFormatCOFF()) {
emitCOFFFeatureSymbol(M);
emitCOFFReplaceableFunctionData(M);
if (M.getModuleFlag("import-call-optimization"))
EnableImportCallOptimization = true;
}
if (!TT.isOSBinFormatELF())
return;
// For emitting build attributes and .note.gnu.property section
auto *TS =
static_cast<AArch64TargetStreamer *>(OutStreamer->getTargetStreamer());
// Assemble feature flags that may require creation of build attributes and a
// note section.
unsigned BAFlags = 0;
unsigned GNUFlags = 0;
if (const auto *BTE = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("branch-target-enforcement"))) {
if (!BTE->isZero()) {
BAFlags |= AArch64BuildAttributes::FeatureAndBitsFlag::Feature_BTI_Flag;
GNUFlags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
}
}
if (const auto *GCS = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("guarded-control-stack"))) {
if (!GCS->isZero()) {
BAFlags |= AArch64BuildAttributes::FeatureAndBitsFlag::Feature_GCS_Flag;
GNUFlags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_GCS;
}
}
if (const auto *Sign = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("sign-return-address"))) {
if (!Sign->isZero()) {
BAFlags |= AArch64BuildAttributes::FeatureAndBitsFlag::Feature_PAC_Flag;
GNUFlags |= ELF::GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
}
}
uint64_t PAuthABIPlatform = -1;
if (const auto *PAP = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("aarch64-elf-pauthabi-platform"))) {
PAuthABIPlatform = PAP->getZExtValue();
}
uint64_t PAuthABIVersion = -1;
if (const auto *PAV = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("aarch64-elf-pauthabi-version"))) {
PAuthABIVersion = PAV->getZExtValue();
}
// Emit AArch64 Build Attributes
emitAttributes(BAFlags, PAuthABIPlatform, PAuthABIVersion, TS);
// Emit a .note.gnu.property section with the flags.
TS->emitNoteSection(GNUFlags, PAuthABIPlatform, PAuthABIVersion);
}
void AArch64AsmPrinter::emitFunctionHeaderComment() {
const AArch64FunctionInfo *FI = MF->getInfo<AArch64FunctionInfo>();
std::optional<std::string> OutlinerString = FI->getOutliningStyle();
if (OutlinerString != std::nullopt)
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 W17, #12 ; W17 := 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(Align(4), &getSubtargetInfo());
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::NOP));
OutStreamer->emitLabel(Target);
recordSled(CurSled, MI, Kind, 2);
}
void AArch64AsmPrinter::emitAttributes(unsigned Flags,
uint64_t PAuthABIPlatform,
uint64_t PAuthABIVersion,
AArch64TargetStreamer *TS) {
PAuthABIPlatform = (uint64_t(-1) == PAuthABIPlatform) ? 0 : PAuthABIPlatform;
PAuthABIVersion = (uint64_t(-1) == PAuthABIVersion) ? 0 : PAuthABIVersion;
if (PAuthABIPlatform || PAuthABIVersion) {
TS->emitAttributesSubsection(
AArch64BuildAttributes::getVendorName(
AArch64BuildAttributes::AEABI_PAUTHABI),
AArch64BuildAttributes::SubsectionOptional::REQUIRED,
AArch64BuildAttributes::SubsectionType::ULEB128);
TS->emitAttribute(AArch64BuildAttributes::getVendorName(
AArch64BuildAttributes::AEABI_PAUTHABI),
AArch64BuildAttributes::TAG_PAUTH_PLATFORM,
PAuthABIPlatform, "");
TS->emitAttribute(AArch64BuildAttributes::getVendorName(
AArch64BuildAttributes::AEABI_PAUTHABI),
AArch64BuildAttributes::TAG_PAUTH_SCHEMA, PAuthABIVersion,
"");
}
unsigned BTIValue =
(Flags & AArch64BuildAttributes::Feature_BTI_Flag) ? 1 : 0;
unsigned PACValue =
(Flags & AArch64BuildAttributes::Feature_PAC_Flag) ? 1 : 0;
unsigned GCSValue =
(Flags & AArch64BuildAttributes::Feature_GCS_Flag) ? 1 : 0;
if (BTIValue || PACValue || GCSValue) {
TS->emitAttributesSubsection(
AArch64BuildAttributes::getVendorName(
AArch64BuildAttributes::AEABI_FEATURE_AND_BITS),
AArch64BuildAttributes::SubsectionOptional::OPTIONAL,
AArch64BuildAttributes::SubsectionType::ULEB128);
TS->emitAttribute(AArch64BuildAttributes::getVendorName(
AArch64BuildAttributes::AEABI_FEATURE_AND_BITS),
AArch64BuildAttributes::TAG_FEATURE_BTI, BTIValue, "");
TS->emitAttribute(AArch64BuildAttributes::getVendorName(
AArch64BuildAttributes::AEABI_FEATURE_AND_BITS),
AArch64BuildAttributes::TAG_FEATURE_PAC, PACValue, "");
TS->emitAttribute(AArch64BuildAttributes::getVendorName(
AArch64BuildAttributes::AEABI_FEATURE_AND_BITS),
AArch64BuildAttributes::TAG_FEATURE_GCS, GCSValue, "");
}
}
// Emit the following code for Intrinsic::{xray_customevent,xray_typedevent}
// (built-in functions __xray_customevent/__xray_typedevent).
//
// .Lxray_event_sled_N:
// b 1f
// save x0 and x1 (and also x2 for TYPED_EVENT_CALL)
// set up x0 and x1 (and also x2 for TYPED_EVENT_CALL)
// bl __xray_CustomEvent or __xray_TypedEvent
// restore x0 and x1 (and also x2 for TYPED_EVENT_CALL)
// 1:
//
// There are 6 instructions for EVENT_CALL and 9 for TYPED_EVENT_CALL.
//
// Then record a sled of kind CUSTOM_EVENT or TYPED_EVENT.
// After patching, b .+N will become a nop.
void AArch64AsmPrinter::LowerPATCHABLE_EVENT_CALL(const MachineInstr &MI,
bool Typed) {
auto &O = *OutStreamer;
MCSymbol *CurSled = OutContext.createTempSymbol("xray_sled_", true);
O.emitLabel(CurSled);
bool MachO = TM.getTargetTriple().isOSBinFormatMachO();
auto *Sym = MCSymbolRefExpr::create(
OutContext.getOrCreateSymbol(
Twine(MachO ? "_" : "") +
(Typed ? "__xray_TypedEvent" : "__xray_CustomEvent")),
OutContext);
if (Typed) {
O.AddComment("Begin XRay typed event");
EmitToStreamer(O, MCInstBuilder(AArch64::B).addImm(9));
EmitToStreamer(O, MCInstBuilder(AArch64::STPXpre)
.addReg(AArch64::SP)
.addReg(AArch64::X0)
.addReg(AArch64::X1)
.addReg(AArch64::SP)
.addImm(-4));
EmitToStreamer(O, MCInstBuilder(AArch64::STRXui)
.addReg(AArch64::X2)
.addReg(AArch64::SP)
.addImm(2));
emitMovXReg(AArch64::X0, MI.getOperand(0).getReg());
emitMovXReg(AArch64::X1, MI.getOperand(1).getReg());
emitMovXReg(AArch64::X2, MI.getOperand(2).getReg());
EmitToStreamer(O, MCInstBuilder(AArch64::BL).addExpr(Sym));
EmitToStreamer(O, MCInstBuilder(AArch64::LDRXui)
.addReg(AArch64::X2)
.addReg(AArch64::SP)
.addImm(2));
O.AddComment("End XRay typed event");
EmitToStreamer(O, MCInstBuilder(AArch64::LDPXpost)
.addReg(AArch64::SP)
.addReg(AArch64::X0)
.addReg(AArch64::X1)
.addReg(AArch64::SP)
.addImm(4));
recordSled(CurSled, MI, SledKind::TYPED_EVENT, 2);
} else {
O.AddComment("Begin XRay custom event");
EmitToStreamer(O, MCInstBuilder(AArch64::B).addImm(6));
EmitToStreamer(O, MCInstBuilder(AArch64::STPXpre)
.addReg(AArch64::SP)
.addReg(AArch64::X0)
.addReg(AArch64::X1)
.addReg(AArch64::SP)
.addImm(-2));
emitMovXReg(AArch64::X0, MI.getOperand(0).getReg());
emitMovXReg(AArch64::X1, MI.getOperand(1).getReg());
EmitToStreamer(O, MCInstBuilder(AArch64::BL).addExpr(Sym));
O.AddComment("End XRay custom event");
EmitToStreamer(O, MCInstBuilder(AArch64::LDPXpost)
.addReg(AArch64::SP)
.addReg(AArch64::X0)
.addReg(AArch64::X1)
.addReg(AArch64::SP)
.addImm(2));
recordSled(CurSled, MI, SledKind::CUSTOM_EVENT, 2);
}
}
void AArch64AsmPrinter::LowerKCFI_CHECK(const MachineInstr &MI) {
Register AddrReg = MI.getOperand(0).getReg();
assert(std::next(MI.getIterator())->isCall() &&
"KCFI_CHECK not followed by a call instruction");
assert(std::next(MI.getIterator())->getOperand(0).getReg() == AddrReg &&
"KCFI_CHECK call target doesn't match call operand");
// Default to using the intra-procedure-call temporary registers for
// comparing the hashes.
unsigned ScratchRegs[] = {AArch64::W16, AArch64::W17};
if (AddrReg == AArch64::XZR) {
// Checking XZR makes no sense. Instead of emitting a load, zero
// ScratchRegs[0] and use it for the ESR AddrIndex below.
AddrReg = getXRegFromWReg(ScratchRegs[0]);
emitMovXReg(AddrReg, AArch64::XZR);
} else {
// If one of the scratch registers is used for the call target (e.g.
// with AArch64::TCRETURNriBTI), we can clobber another caller-saved
// temporary register instead (in this case, AArch64::W9) as the check
// is immediately followed by the call instruction.
for (auto &Reg : ScratchRegs) {
if (Reg == getWRegFromXReg(AddrReg)) {
Reg = AArch64::W9;
break;
}
}
assert(ScratchRegs[0] != AddrReg && ScratchRegs[1] != AddrReg &&
"Invalid scratch registers for KCFI_CHECK");
// Adjust the offset for patchable-function-prefix. This assumes that
// patchable-function-prefix is the same for all functions.
int64_t PrefixNops = 0;
(void)MI.getMF()
->getFunction()
.getFnAttribute("patchable-function-prefix")
.getValueAsString()
.getAsInteger(10, PrefixNops);
// Load the target function type hash.
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::LDURWi)
.addReg(ScratchRegs[0])
.addReg(AddrReg)
.addImm(-(PrefixNops * 4 + 4)));
}
// Load the expected type hash.
const int64_t Type = MI.getOperand(1).getImm();
emitMOVK(ScratchRegs[1], Type & 0xFFFF, 0);
emitMOVK(ScratchRegs[1], (Type >> 16) & 0xFFFF, 16);
// Compare the hashes and trap if there's a mismatch.
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::SUBSWrs)
.addReg(AArch64::WZR)
.addReg(ScratchRegs[0])
.addReg(ScratchRegs[1])
.addImm(0));
MCSymbol *Pass = OutContext.createTempSymbol();
EmitToStreamer(*OutStreamer,
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::EQ)
.addExpr(MCSymbolRefExpr::create(Pass, OutContext)));
// The base ESR is 0x8000 and the register information is encoded in bits
// 0-9 as follows:
// - 0-4: n, where the register Xn contains the target address
// - 5-9: m, where the register Wm contains the expected type hash
// Where n, m are in [0, 30].
unsigned TypeIndex = ScratchRegs[1] - AArch64::W0;
unsigned AddrIndex;
switch (AddrReg) {
default:
AddrIndex = AddrReg - AArch64::X0;
break;
case AArch64::FP:
AddrIndex = 29;
break;
case AArch64::LR:
AddrIndex = 30;
break;
}
assert(AddrIndex < 31 && TypeIndex < 31);
unsigned ESR = 0x8000 | ((TypeIndex & 31) << 5) | (AddrIndex & 31);
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::BRK).addImm(ESR));
OutStreamer->emitLabel(Pass);
}
void AArch64AsmPrinter::LowerHWASAN_CHECK_MEMACCESS(const MachineInstr &MI) {
Register Reg = MI.getOperand(0).getReg();
// The HWASan pass won't emit a CHECK_MEMACCESS intrinsic with a pointer
// statically known to be zero. However, conceivably, the HWASan pass may
// encounter a "cannot currently statically prove to be null" pointer (and is
// therefore unable to omit the intrinsic) that later optimization passes
// convert into a statically known-null pointer.
if (Reg == AArch64::XZR)
return;
bool IsShort =
((MI.getOpcode() == AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES) ||
(MI.getOpcode() ==
AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES_FIXEDSHADOW));
uint32_t AccessInfo = MI.getOperand(1).getImm();
bool IsFixedShadow =
((MI.getOpcode() == AArch64::HWASAN_CHECK_MEMACCESS_FIXEDSHADOW) ||
(MI.getOpcode() ==
AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES_FIXEDSHADOW));
uint64_t FixedShadowOffset = IsFixedShadow ? MI.getOperand(2).getImm() : 0;
MCSymbol *&Sym = HwasanMemaccessSymbols[HwasanMemaccessTuple(
Reg, IsShort, AccessInfo, IsFixedShadow, FixedShadowOffset)];
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 (IsFixedShadow)
SymName += "_fixed_" + utostr(FixedShadowOffset);
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());
// AArch64Subtarget is huge, so heap allocate it so we don't run out of stack
// space.
auto STI = std::make_unique<AArch64Subtarget>(
TT, TM.getTargetCPU(), TM.getTargetCPU(), TM.getTargetFeatureString(), TM,
true);
this->STI = STI.get();
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);
bool IsFixedShadow = std::get<3>(P.first);
uint64_t FixedShadowOffset = std::get<4>(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);
EmitToStreamer(MCInstBuilder(AArch64::SBFMXri)
.addReg(AArch64::X16)
.addReg(Reg)
.addImm(4)
.addImm(55));
if (IsFixedShadow) {
// Aarch64 makes it difficult to embed large constants in the code.
// Fortuitously, kShadowBaseAlignment == 32, so we use the 32-bit
// left-shift option in the MOV instruction. Combined with the 16-bit
// immediate, this is enough to represent any offset up to 2**48.
emitMOVZ(AArch64::X17, FixedShadowOffset >> 32, 32);
EmitToStreamer(MCInstBuilder(AArch64::LDRBBroX)
.addReg(AArch64::W16)
.addReg(AArch64::X17)
.addReg(AArch64::X16)
.addImm(0)
.addImm(0));
} else {
EmitToStreamer(MCInstBuilder(AArch64::LDRBBroX)
.addReg(AArch64::W16)
.addReg(IsShort ? AArch64::X20 : AArch64::X9)
.addReg(AArch64::X16)
.addImm(0)
.addImm(0));
}
EmitToStreamer(MCInstBuilder(AArch64::SUBSXrs)
.addReg(AArch64::XZR)
.addReg(AArch64::X16)
.addReg(Reg)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSR, 56)));
MCSymbol *HandleMismatchOrPartialSym = OutContext.createTempSymbol();
EmitToStreamer(MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::NE)
.addExpr(MCSymbolRefExpr::create(
HandleMismatchOrPartialSym, OutContext)));
MCSymbol *ReturnSym = OutContext.createTempSymbol();
OutStreamer->emitLabel(ReturnSym);
EmitToStreamer(MCInstBuilder(AArch64::RET).addReg(AArch64::LR));
OutStreamer->emitLabel(HandleMismatchOrPartialSym);
if (HasMatchAllTag) {
EmitToStreamer(MCInstBuilder(AArch64::UBFMXri)
.addReg(AArch64::X17)
.addReg(Reg)
.addImm(56)
.addImm(63));
EmitToStreamer(MCInstBuilder(AArch64::SUBSXri)
.addReg(AArch64::XZR)
.addReg(AArch64::X17)
.addImm(MatchAllTag)
.addImm(0));
EmitToStreamer(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::EQ)
.addExpr(MCSymbolRefExpr::create(ReturnSym, OutContext)));
}
if (IsShort) {
EmitToStreamer(MCInstBuilder(AArch64::SUBSWri)
.addReg(AArch64::WZR)
.addReg(AArch64::W16)
.addImm(15)
.addImm(0));
MCSymbol *HandleMismatchSym = OutContext.createTempSymbol();
EmitToStreamer(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::HI)
.addExpr(MCSymbolRefExpr::create(HandleMismatchSym, OutContext)));
EmitToStreamer(MCInstBuilder(AArch64::ANDXri)
.addReg(AArch64::X17)
.addReg(Reg)
.addImm(AArch64_AM::encodeLogicalImmediate(0xf, 64)));
if (Size != 1)
EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
.addReg(AArch64::X17)
.addReg(AArch64::X17)
.addImm(Size - 1)
.addImm(0));
EmitToStreamer(MCInstBuilder(AArch64::SUBSWrs)
.addReg(AArch64::WZR)
.addReg(AArch64::W16)
.addReg(AArch64::W17)
.addImm(0));
EmitToStreamer(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::LS)
.addExpr(MCSymbolRefExpr::create(HandleMismatchSym, OutContext)));
EmitToStreamer(MCInstBuilder(AArch64::ORRXri)
.addReg(AArch64::X16)
.addReg(Reg)
.addImm(AArch64_AM::encodeLogicalImmediate(0xf, 64)));
EmitToStreamer(MCInstBuilder(AArch64::LDRBBui)
.addReg(AArch64::W16)
.addReg(AArch64::X16)
.addImm(0));
EmitToStreamer(
MCInstBuilder(AArch64::SUBSXrs)
.addReg(AArch64::XZR)
.addReg(AArch64::X16)
.addReg(Reg)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSR, 56)));
EmitToStreamer(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::EQ)
.addExpr(MCSymbolRefExpr::create(ReturnSym, OutContext)));
OutStreamer->emitLabel(HandleMismatchSym);
}
EmitToStreamer(MCInstBuilder(AArch64::STPXpre)
.addReg(AArch64::SP)
.addReg(AArch64::X0)
.addReg(AArch64::X1)
.addReg(AArch64::SP)
.addImm(-32));
EmitToStreamer(MCInstBuilder(AArch64::STPXi)
.addReg(AArch64::FP)
.addReg(AArch64::LR)
.addReg(AArch64::SP)
.addImm(29));
if (Reg != AArch64::X0)
emitMovXReg(AArch64::X0, Reg);
emitMOVZ(AArch64::X1, AccessInfo & HWASanAccessInfo::RuntimeMask, 0);
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.
EmitToStreamer(MCInstBuilder(AArch64::B).addExpr(HwasanTagMismatchRef));
} 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.
EmitToStreamer(MCInstBuilder(AArch64::ADRP)
.addReg(AArch64::X16)
.addExpr(MCSpecifierExpr::create(HwasanTagMismatchRef,
AArch64::S_GOT_PAGE,
OutContext)));
EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
.addReg(AArch64::X16)
.addReg(AArch64::X16)
.addExpr(MCSpecifierExpr::create(HwasanTagMismatchRef,
AArch64::S_GOT_LO12,
OutContext)));
EmitToStreamer(MCInstBuilder(AArch64::BR).addReg(AArch64::X16));
}
}
this->STI = nullptr;
}
static void emitAuthenticatedPointer(MCStreamer &OutStreamer,
MCSymbol *StubLabel,
const MCExpr *StubAuthPtrRef) {
// sym$auth_ptr$key$disc:
OutStreamer.emitLabel(StubLabel);
OutStreamer.emitValue(StubAuthPtrRef, /*size=*/8);
}
void AArch64AsmPrinter::emitEndOfAsmFile(Module &M) {
emitHwasanMemaccessSymbols(M);
const Triple &TT = TM.getTargetTriple();
if (TT.isOSBinFormatMachO()) {
// Output authenticated pointers as indirect symbols, if we have any.
MachineModuleInfoMachO &MMIMacho =
MMI->getObjFileInfo<MachineModuleInfoMachO>();
auto Stubs = MMIMacho.getAuthGVStubList();
if (!Stubs.empty()) {
// Switch to the "__auth_ptr" section.
OutStreamer->switchSection(
OutContext.getMachOSection("__DATA", "__auth_ptr", MachO::S_REGULAR,
SectionKind::getMetadata()));
emitAlignment(Align(8));
for (const auto &Stub : Stubs)
emitAuthenticatedPointer(*OutStreamer, Stub.first, Stub.second);
OutStreamer->addBlankLine();
}
// 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->emitSubsectionsViaSymbols();
}
if (TT.isOSBinFormatELF()) {
// Output authenticated pointers as indirect symbols, if we have any.
MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
auto Stubs = MMIELF.getAuthGVStubList();
if (!Stubs.empty()) {
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
OutStreamer->switchSection(TLOF.getDataSection());
emitAlignment(Align(8));
for (const auto &Stub : Stubs)
emitAuthenticatedPointer(*OutStreamer, Stub.first, Stub.second);
OutStreamer->addBlankLine();
}
// With signed ELF GOT enabled, the linker looks at the symbol type to
// choose between keys IA (for STT_FUNC) and DA (for other types). Symbols
// for functions not defined in the module have STT_NOTYPE type by default.
// This makes linker to emit signing schema with DA key (instead of IA) for
// corresponding R_AARCH64_AUTH_GLOB_DAT dynamic reloc. To avoid that, force
// all function symbols used in the module to have STT_FUNC type. See
// https://github.com/ARM-software/abi-aa/blob/main/pauthabielf64/pauthabielf64.rst#default-signing-schema
const auto *PtrAuthELFGOTFlag = mdconst::extract_or_null<ConstantInt>(
M.getModuleFlag("ptrauth-elf-got"));
if (PtrAuthELFGOTFlag && PtrAuthELFGOTFlag->getZExtValue() == 1)
for (const GlobalValue &GV : M.global_values())
if (!GV.use_empty() && isa<Function>(GV) &&
!GV.getName().starts_with("llvm."))
OutStreamer->emitSymbolAttribute(getSymbol(&GV),
MCSA_ELF_TypeFunction);
}
// Emit stack and fault map information.
FM.serializeToFaultMapSection();
// If import call optimization is enabled, emit the appropriate section.
// We do this whether or not we recorded any import calls.
if (EnableImportCallOptimization && TT.isOSBinFormatCOFF()) {
OutStreamer->switchSection(getObjFileLowering().getImportCallSection());
// Section always starts with some magic.
constexpr char ImpCallMagic[12] = "Imp_Call_V1";
OutStreamer->emitBytes(StringRef{ImpCallMagic, sizeof(ImpCallMagic)});
// Layout of this section is:
// Per section that contains calls to imported functions:
// uint32_t SectionSize: Size in bytes for information in this section.
// uint32_t Section Number
// Per call to imported function in section:
// uint32_t Kind: the kind of imported function.
// uint32_t BranchOffset: the offset of the branch instruction in its
// parent section.
// uint32_t TargetSymbolId: the symbol id of the called function.
for (auto &[Section, CallsToImportedFuncs] :
SectionToImportedFunctionCalls) {
unsigned SectionSize =
sizeof(uint32_t) * (2 + 3 * CallsToImportedFuncs.size());
OutStreamer->emitInt32(SectionSize);
OutStreamer->emitCOFFSecNumber(Section->getBeginSymbol());
for (auto &[CallsiteSymbol, CalledSymbol] : CallsToImportedFuncs) {
// Kind is always IMAGE_REL_ARM64_DYNAMIC_IMPORT_CALL (0x13).
OutStreamer->emitInt32(0x13);
OutStreamer->emitCOFFSecOffset(CallsiteSymbol);
OutStreamer->emitCOFFSymbolIndex(CalledSymbol);
}
}
}
}
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(Reg.isPhysical());
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;
case 't':
Reg = getXRegFromXRegTuple(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();
MCRegister 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);
// If this is an x register tuple, print an x register.
if (AArch64::GPR64x8ClassRegClass.contains(Reg))
return printAsmMRegister(MO, 't', 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 if (AArch64::PNRRegClass.contains(Reg)) {
RegClass = &AArch64::PNRRegClass;
} 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 = llvm::size(MI->debug_operands()); I < E; ++I) {
if (I != 0)
OS << ", ";
printOperand(MI, I, OS);
}
OS << ']';
OS << "+";
printOperand(MI, NOps - 2, OS);
}
void AArch64AsmPrinter::emitJumpTableImpl(const MachineJumpTableInfo &MJTI,
ArrayRef<unsigned> JumpTableIndices) {
// Fast return if there is nothing to emit to avoid creating empty sections.
if (JumpTableIndices.empty())
return;
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
const auto &F = MF->getFunction();
ArrayRef<MachineJumpTableEntry> JT = MJTI.getJumpTables();
MCSection *ReadOnlySec = nullptr;
if (TM.Options.EnableStaticDataPartitioning) {
ReadOnlySec =
TLOF.getSectionForJumpTable(F, TM, &JT[JumpTableIndices.front()]);
} else {
ReadOnlySec = TLOF.getSectionForJumpTable(F, TM);
}
OutStreamer->switchSection(ReadOnlySec);
auto AFI = MF->getInfo<AArch64FunctionInfo>();
for (unsigned JTI : JumpTableIndices) {
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);
}
}
}
std::tuple<const MCSymbol *, uint64_t, const MCSymbol *,
codeview::JumpTableEntrySize>
AArch64AsmPrinter::getCodeViewJumpTableInfo(int JTI,
const MachineInstr *BranchInstr,
const MCSymbol *BranchLabel) const {
const auto AFI = MF->getInfo<AArch64FunctionInfo>();
const auto Base = AArch64FI->getJumpTableEntryPCRelSymbol(JTI);
codeview::JumpTableEntrySize EntrySize;
switch (AFI->getJumpTableEntrySize(JTI)) {
case 1:
EntrySize = codeview::JumpTableEntrySize::UInt8ShiftLeft;
break;
case 2:
EntrySize = codeview::JumpTableEntrySize::UInt16ShiftLeft;
break;
case 4:
EntrySize = codeview::JumpTableEntrySize::Int32;
break;
default:
llvm_unreachable("Unexpected jump table entry size");
}
return std::make_tuple(Base, 0, BranchLabel, EntrySize);
}
void AArch64AsmPrinter::emitFunctionEntryLabel() {
const Triple &TT = TM.getTargetTriple();
if (TT.isOSBinFormatELF() &&
(MF->getFunction().getCallingConv() == CallingConv::AArch64_VectorCall ||
MF->getFunction().getCallingConv() ==
CallingConv::AArch64_SVE_VectorCall ||
MF->getInfo<AArch64FunctionInfo>()->isSVECC())) {
auto *TS =
static_cast<AArch64TargetStreamer *>(OutStreamer->getTargetStreamer());
TS->emitDirectiveVariantPCS(CurrentFnSym);
}
AsmPrinter::emitFunctionEntryLabel();
if (TT.isWindowsArm64EC() && !MF->getFunction().hasLocalLinkage()) {
// For ARM64EC targets, a function definition's name is mangled differently
// from the normal symbol, emit required aliases here.
auto emitFunctionAlias = [&](MCSymbol *Src, MCSymbol *Dst) {
OutStreamer->emitSymbolAttribute(Src, MCSA_WeakAntiDep);
OutStreamer->emitAssignment(
Src, MCSymbolRefExpr::create(Dst, MMI->getContext()));
};
auto getSymbolFromMetadata = [&](StringRef Name) {
MCSymbol *Sym = nullptr;
if (MDNode *Node = MF->getFunction().getMetadata(Name)) {
StringRef NameStr = cast<MDString>(Node->getOperand(0))->getString();
Sym = MMI->getContext().getOrCreateSymbol(NameStr);
}
return Sym;
};
SmallVector<MDNode *> UnmangledNames;
MF->getFunction().getMetadata("arm64ec_unmangled_name", UnmangledNames);
for (MDNode *Node : UnmangledNames) {
StringRef NameStr = cast<MDString>(Node->getOperand(0))->getString();
MCSymbol *UnmangledSym = MMI->getContext().getOrCreateSymbol(NameStr);
if (std::optional<std::string> MangledName =
getArm64ECMangledFunctionName(UnmangledSym->getName())) {
MCSymbol *ECMangledSym =
MMI->getContext().getOrCreateSymbol(*MangledName);
emitFunctionAlias(UnmangledSym, ECMangledSym);
}
}
if (MCSymbol *ECMangledSym =
getSymbolFromMetadata("arm64ec_ecmangled_name"))
emitFunctionAlias(ECMangledSym, CurrentFnSym);
}
}
void AArch64AsmPrinter::emitXXStructor(const DataLayout &DL,
const Constant *CV) {
if (const auto *CPA = dyn_cast<ConstantPtrAuth>(CV))
if (CPA->hasAddressDiscriminator() &&
!CPA->hasSpecialAddressDiscriminator(
ConstantPtrAuth::AddrDiscriminator_CtorsDtors))
report_fatal_error(
"unexpected address discrimination value for ctors/dtors entry, only "
"'ptr inttoptr (i64 1 to ptr)' is allowed");
// If we have signed pointers in xxstructors list, they'll be lowered to @AUTH
// MCExpr's via AArch64AsmPrinter::lowerConstantPtrAuth. It does not look at
// actual address discrimination value and only checks
// hasAddressDiscriminator(), so it's OK to leave special address
// discrimination value here.
AsmPrinter::emitXXStructor(DL, CV);
}
void AArch64AsmPrinter::emitGlobalAlias(const Module &M,
const GlobalAlias &GA) {
if (auto F = dyn_cast_or_null<Function>(GA.getAliasee())) {
// Global aliases must point to a definition, but unmangled patchable
// symbols are special and need to point to an undefined symbol with "EXP+"
// prefix. Such undefined symbol is resolved by the linker by creating
// x86 thunk that jumps back to the actual EC target.
if (MDNode *Node = F->getMetadata("arm64ec_exp_name")) {
StringRef ExpStr = cast<MDString>(Node->getOperand(0))->getString();
MCSymbol *ExpSym = MMI->getContext().getOrCreateSymbol(ExpStr);
MCSymbol *Sym = MMI->getContext().getOrCreateSymbol(GA.getName());
OutStreamer->beginCOFFSymbolDef(ExpSym);
OutStreamer->emitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_EXTERNAL);
OutStreamer->emitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
<< COFF::SCT_COMPLEX_TYPE_SHIFT);
OutStreamer->endCOFFSymbolDef();
OutStreamer->beginCOFFSymbolDef(Sym);
OutStreamer->emitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_EXTERNAL);
OutStreamer->emitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
<< COFF::SCT_COMPLEX_TYPE_SHIFT);
OutStreamer->endCOFFSymbolDef();
OutStreamer->emitSymbolAttribute(Sym, MCSA_Weak);
OutStreamer->emitAssignment(
Sym, MCSymbolRefExpr::create(ExpSym, MMI->getContext()));
return;
}
}
AsmPrinter::emitGlobalAlias(M, GA);
}
/// 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::LowerHardenedBRJumpTable(const MachineInstr &MI) {
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
assert(MJTI && "Can't lower jump-table dispatch without JTI");
const std::vector<MachineJumpTableEntry> &JTs = MJTI->getJumpTables();
assert(!JTs.empty() && "Invalid JT index for jump-table dispatch");
// Emit:
// mov x17, #<size of table> ; depending on table size, with MOVKs
// cmp x16, x17 ; or #imm if table size fits in 12-bit
// csel x16, x16, xzr, ls ; check for index overflow
//
// adrp x17, Ltable@PAGE ; materialize table address
// add x17, Ltable@PAGEOFF
// ldrsw x16, [x17, x16, lsl #2] ; load table entry
//
// Lanchor:
// adr x17, Lanchor ; compute target address
// add x16, x17, x16
// br x16 ; branch to target
MachineOperand JTOp = MI.getOperand(0);
unsigned JTI = JTOp.getIndex();
assert(!AArch64FI->getJumpTableEntryPCRelSymbol(JTI) &&
"unsupported compressed jump table");
const uint64_t NumTableEntries = JTs[JTI].MBBs.size();
// cmp only supports a 12-bit immediate. If we need more, materialize the
// immediate, using x17 as a scratch register.
uint64_t MaxTableEntry = NumTableEntries - 1;
if (isUInt<12>(MaxTableEntry)) {
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::SUBSXri)
.addReg(AArch64::XZR)
.addReg(AArch64::X16)
.addImm(MaxTableEntry)
.addImm(0));
} else {
emitMOVZ(AArch64::X17, static_cast<uint16_t>(MaxTableEntry), 0);
// It's sad that we have to manually materialize instructions, but we can't
// trivially reuse the main pseudo expansion logic.
// A MOVK sequence is easy enough to generate and handles the general case.
for (int Offset = 16; Offset < 64; Offset += 16) {
if ((MaxTableEntry >> Offset) == 0)
break;
emitMOVK(AArch64::X17, static_cast<uint16_t>(MaxTableEntry >> Offset),
Offset);
}
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::SUBSXrs)
.addReg(AArch64::XZR)
.addReg(AArch64::X16)
.addReg(AArch64::X17)
.addImm(0));
}
// This picks entry #0 on failure.
// We might want to trap instead.
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::CSELXr)
.addReg(AArch64::X16)
.addReg(AArch64::X16)
.addReg(AArch64::XZR)
.addImm(AArch64CC::LS));
// Prepare the @PAGE/@PAGEOFF low/high operands.
MachineOperand JTMOHi(JTOp), JTMOLo(JTOp);
MCOperand JTMCHi, JTMCLo;
JTMOHi.setTargetFlags(AArch64II::MO_PAGE);
JTMOLo.setTargetFlags(AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
MCInstLowering.lowerOperand(JTMOHi, JTMCHi);
MCInstLowering.lowerOperand(JTMOLo, JTMCLo);
EmitToStreamer(
*OutStreamer,
MCInstBuilder(AArch64::ADRP).addReg(AArch64::X17).addOperand(JTMCHi));
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::ADDXri)
.addReg(AArch64::X17)
.addReg(AArch64::X17)
.addOperand(JTMCLo)
.addImm(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::LDRSWroX)
.addReg(AArch64::X16)
.addReg(AArch64::X17)
.addReg(AArch64::X16)
.addImm(0)
.addImm(1));
MCSymbol *AdrLabel = MF->getContext().createTempSymbol();
const auto *AdrLabelE = MCSymbolRefExpr::create(AdrLabel, MF->getContext());
AArch64FI->setJumpTableEntryInfo(JTI, 4, AdrLabel);
OutStreamer->emitLabel(AdrLabel);
EmitToStreamer(
*OutStreamer,
MCInstBuilder(AArch64::ADR).addReg(AArch64::X17).addExpr(AdrLabelE));
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::ADDXrs)
.addReg(AArch64::X16)
.addReg(AArch64::X17)
.addReg(AArch64::X16)
.addImm(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::BR).addReg(AArch64::X16));
}
void AArch64AsmPrinter::LowerMOPS(llvm::MCStreamer &OutStreamer,
const llvm::MachineInstr &MI) {
unsigned Opcode = MI.getOpcode();
assert(STI->hasMOPS());
assert(STI->hasMTE() || Opcode != AArch64::MOPSMemorySetTaggingPseudo);
const auto Ops = [Opcode]() -> std::array<unsigned, 3> {
if (Opcode == AArch64::MOPSMemoryCopyPseudo)
return {AArch64::CPYFP, AArch64::CPYFM, AArch64::CPYFE};
if (Opcode == AArch64::MOPSMemoryMovePseudo)
return {AArch64::CPYP, AArch64::CPYM, AArch64::CPYE};
if (Opcode == AArch64::MOPSMemorySetPseudo)
return {AArch64::SETP, AArch64::SETM, AArch64::SETE};
if (Opcode == AArch64::MOPSMemorySetTaggingPseudo)
return {AArch64::SETGP, AArch64::SETGM, AArch64::MOPSSETGE};
llvm_unreachable("Unhandled memory operation pseudo");
}();
const bool IsSet = Opcode == AArch64::MOPSMemorySetPseudo ||
Opcode == AArch64::MOPSMemorySetTaggingPseudo;
for (auto Op : Ops) {
int i = 0;
auto MCIB = MCInstBuilder(Op);
// Destination registers
MCIB.addReg(MI.getOperand(i++).getReg());
MCIB.addReg(MI.getOperand(i++).getReg());
if (!IsSet)
MCIB.addReg(MI.getOperand(i++).getReg());
// Input registers
MCIB.addReg(MI.getOperand(i++).getReg());
MCIB.addReg(MI.getOperand(i++).getReg());
MCIB.addReg(MI.getOperand(i++).getReg());
EmitToStreamer(OutStreamer, MCIB);
}
}
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::NOP));
}
// 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:
emitMOVZ(ScratchReg, (CallTarget >> 32) & 0xFFFF, 32);
emitMOVK(ScratchReg, (CallTarget >> 16) & 0xFFFF, 16);
emitMOVK(ScratchReg, CallTarget & 0xFFFF, 0);
EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::BLR).addReg(ScratchReg));
}
// Emit padding.
unsigned NumBytes = Opers.getNumPatchBytes();
assert(NumBytes >= EncodedBytes &&
"Patchpoint can't request size less than the length of a call.");
assert((NumBytes - EncodedBytes) % 4 == 0 &&
"Invalid number of NOP bytes requested!");
for (unsigned i = EncodedBytes; i < NumBytes; i += 4)
EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::NOP));
}
void AArch64AsmPrinter::LowerSTATEPOINT(MCStreamer &OutStreamer, StackMaps &SM,
const MachineInstr &MI) {
StatepointOpers SOpers(&MI);
if (unsigned PatchBytes = SOpers.getNumPatchBytes()) {
assert(PatchBytes % 4 == 0 && "Invalid number of NOP bytes requested!");
for (unsigned i = 0; i < PatchBytes; i += 4)
EmitToStreamer(OutStreamer, MCInstBuilder(AArch64::NOP));
} else {
// Lower call target and choose correct opcode
const MachineOperand &CallTarget = SOpers.getCallTarget();
MCOperand CallTargetMCOp;
unsigned CallOpcode;
switch (CallTarget.getType()) {
case MachineOperand::MO_GlobalAddress:
case MachineOperand::MO_ExternalSymbol:
MCInstLowering.lowerOperand(CallTarget, CallTargetMCOp);
CallOpcode = AArch64::BL;
break;
case MachineOperand::MO_Immediate:
CallTargetMCOp = MCOperand::createImm(CallTarget.getImm());
CallOpcode = AArch64::BL;
break;
case MachineOperand::MO_Register:
CallTargetMCOp = MCOperand::createReg(CallTarget.getReg());
CallOpcode = AArch64::BLR;
break;
default:
llvm_unreachable("Unsupported operand type in statepoint call target");
break;
}
EmitToStreamer(OutStreamer,
MCInstBuilder(CallOpcode).addOperand(CallTargetMCOp));
}
auto &Ctx = OutStreamer.getContext();
MCSymbol *MILabel = Ctx.createTempSymbol();
OutStreamer.emitLabel(MILabel);
SM.recordStatepoint(*MILabel, MI);
}
void AArch64AsmPrinter::LowerFAULTING_OP(const MachineInstr &FaultingMI) {
// FAULTING_LOAD_OP <def>, <faltinf type>, <MBB handler>,
// <opcode>, <operands>
Register DefRegister = FaultingMI.getOperand(0).getReg();
FaultMaps::FaultKind FK =
static_cast<FaultMaps::FaultKind>(FaultingMI.getOperand(1).getImm());
MCSymbol *HandlerLabel = FaultingMI.getOperand(2).getMBB()->getSymbol();
unsigned Opcode = FaultingMI.getOperand(3).getImm();
unsigned OperandsBeginIdx = 4;
auto &Ctx = OutStreamer->getContext();
MCSymbol *FaultingLabel = Ctx.createTempSymbol();
OutStreamer->emitLabel(FaultingLabel);
assert(FK < FaultMaps::FaultKindMax && "Invalid Faulting Kind!");
FM.recordFaultingOp(FK, FaultingLabel, HandlerLabel);
MCInst MI;
MI.setOpcode(Opcode);
if (DefRegister != (Register)0)
MI.addOperand(MCOperand::createReg(DefRegister));
for (const MachineOperand &MO :
llvm::drop_begin(FaultingMI.operands(), OperandsBeginIdx)) {
MCOperand Dest;
lowerOperand(MO, Dest);
MI.addOperand(Dest);
}
OutStreamer->AddComment("on-fault: " + HandlerLabel->getName());
EmitToStreamer(MI);
}
void AArch64AsmPrinter::emitMovXReg(Register Dest, Register Src) {
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::ORRXrs)
.addReg(Dest)
.addReg(AArch64::XZR)
.addReg(Src)
.addImm(0));
}
void AArch64AsmPrinter::emitMOVZ(Register Dest, uint64_t Imm, unsigned Shift) {
bool Is64Bit = AArch64::GPR64RegClass.contains(Dest);
EmitToStreamer(*OutStreamer,
MCInstBuilder(Is64Bit ? AArch64::MOVZXi : AArch64::MOVZWi)
.addReg(Dest)
.addImm(Imm)
.addImm(Shift));
}
void AArch64AsmPrinter::emitMOVK(Register Dest, uint64_t Imm, unsigned Shift) {
bool Is64Bit = AArch64::GPR64RegClass.contains(Dest);
EmitToStreamer(*OutStreamer,
MCInstBuilder(Is64Bit ? AArch64::MOVKXi : AArch64::MOVKWi)
.addReg(Dest)
.addReg(Dest)
.addImm(Imm)
.addImm(Shift));
}
void AArch64AsmPrinter::emitAUT(AArch64PACKey::ID Key, Register Pointer,
Register Disc) {
bool IsZeroDisc = Disc == AArch64::XZR;
unsigned Opcode = getAUTOpcodeForKey(Key, IsZeroDisc);
// autiza x16 ; if IsZeroDisc
// autia x16, x17 ; if !IsZeroDisc
MCInst AUTInst;
AUTInst.setOpcode(Opcode);
AUTInst.addOperand(MCOperand::createReg(Pointer));
AUTInst.addOperand(MCOperand::createReg(Pointer));
if (!IsZeroDisc)
AUTInst.addOperand(MCOperand::createReg(Disc));
EmitToStreamer(AUTInst);
}
void AArch64AsmPrinter::emitPAC(AArch64PACKey::ID Key, Register Pointer,
Register Disc) {
bool IsZeroDisc = Disc == AArch64::XZR;
unsigned Opcode = getPACOpcodeForKey(Key, IsZeroDisc);
// paciza x16 ; if IsZeroDisc
// pacia x16, x17 ; if !IsZeroDisc
MCInst PACInst;
PACInst.setOpcode(Opcode);
PACInst.addOperand(MCOperand::createReg(Pointer));
PACInst.addOperand(MCOperand::createReg(Pointer));
if (!IsZeroDisc)
PACInst.addOperand(MCOperand::createReg(Disc));
EmitToStreamer(PACInst);
}
void AArch64AsmPrinter::emitBLRA(bool IsCall, AArch64PACKey::ID Key,
Register Target, Register Disc) {
bool IsZeroDisc = Disc == AArch64::XZR;
unsigned Opcode = getBranchOpcodeForKey(IsCall, Key, IsZeroDisc);
// blraaz x16 ; if IsZeroDisc
// blraa x16, x17 ; if !IsZeroDisc
MCInst Inst;
Inst.setOpcode(Opcode);
Inst.addOperand(MCOperand::createReg(Target));
if (!IsZeroDisc)
Inst.addOperand(MCOperand::createReg(Disc));
EmitToStreamer(Inst);
}
void AArch64AsmPrinter::emitFMov0(const MachineInstr &MI) {
Register DestReg = MI.getOperand(0).getReg();
if (!STI->hasZeroCycleZeroingFPWorkaround() && STI->isNeonAvailable()) {
if (STI->hasZeroCycleZeroingFPR64()) {
// Convert H/S register to corresponding D register
const AArch64RegisterInfo *TRI = STI->getRegisterInfo();
if (AArch64::FPR16RegClass.contains(DestReg))
DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::hsub,
&AArch64::FPR64RegClass);
else if (AArch64::FPR32RegClass.contains(DestReg))
DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::ssub,
&AArch64::FPR64RegClass);
else
assert(AArch64::FPR64RegClass.contains(DestReg));
MCInst MOVI;
MOVI.setOpcode(AArch64::MOVID);
MOVI.addOperand(MCOperand::createReg(DestReg));
MOVI.addOperand(MCOperand::createImm(0));
EmitToStreamer(*OutStreamer, MOVI);
++NumZCZeroingInstrsFPR;
} else if (STI->hasZeroCycleZeroingFPR128()) {
// Convert H/S/D register to corresponding Q register
const AArch64RegisterInfo *TRI = STI->getRegisterInfo();
if (AArch64::FPR16RegClass.contains(DestReg)) {
DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::hsub,
&AArch64::FPR128RegClass);
} else if (AArch64::FPR32RegClass.contains(DestReg)) {
DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::ssub,
&AArch64::FPR128RegClass);
} else {
assert(AArch64::FPR64RegClass.contains(DestReg));
DestReg = TRI->getMatchingSuperReg(DestReg, AArch64::dsub,
&AArch64::FPR128RegClass);
}
MCInst MOVI;
MOVI.setOpcode(AArch64::MOVIv2d_ns);
MOVI.addOperand(MCOperand::createReg(DestReg));
MOVI.addOperand(MCOperand::createImm(0));
EmitToStreamer(*OutStreamer, MOVI);
++NumZCZeroingInstrsFPR;
} else {
emitFMov0AsFMov(MI, DestReg);
}
} else {
emitFMov0AsFMov(MI, DestReg);
}
}
void AArch64AsmPrinter::emitFMov0AsFMov(const MachineInstr &MI,
Register DestReg) {
MCInst FMov;
switch (MI.getOpcode()) {
default:
llvm_unreachable("Unexpected opcode");
case AArch64::FMOVH0:
FMov.setOpcode(STI->hasFullFP16() ? AArch64::FMOVWHr : AArch64::FMOVWSr);
if (!STI->hasFullFP16())
DestReg = (AArch64::S0 + (DestReg - AArch64::H0));
FMov.addOperand(MCOperand::createReg(DestReg));
FMov.addOperand(MCOperand::createReg(AArch64::WZR));
break;
case AArch64::FMOVS0:
FMov.setOpcode(AArch64::FMOVWSr);
FMov.addOperand(MCOperand::createReg(DestReg));
FMov.addOperand(MCOperand::createReg(AArch64::WZR));
break;
case AArch64::FMOVD0:
FMov.setOpcode(AArch64::FMOVXDr);
FMov.addOperand(MCOperand::createReg(DestReg));
FMov.addOperand(MCOperand::createReg(AArch64::XZR));
break;
}
EmitToStreamer(*OutStreamer, FMov);
}
Register AArch64AsmPrinter::emitPtrauthDiscriminator(uint64_t Disc,
Register AddrDisc,
Register ScratchReg,
bool MayClobberAddrDisc) {
assert(isPtrauthRegSafe(ScratchReg) &&
"Safe scratch register must be provided by the caller");
assert(isUInt<16>(Disc) && "Constant discriminator is too wide");
// So far we've used NoRegister in pseudos. Now we need real encodings.
if (AddrDisc == AArch64::NoRegister)
AddrDisc = AArch64::XZR;
// If there is no constant discriminator, there's no blend involved:
// just use the address discriminator register as-is (XZR or not).
if (!Disc)
return AddrDisc;
// If there's only a constant discriminator, MOV it into the scratch register.
if (AddrDisc == AArch64::XZR) {
emitMOVZ(ScratchReg, Disc, 0);
return ScratchReg;
}
// If there are both, emit a blend into the scratch register.
// Check if we can save one MOV instruction.
if (MayClobberAddrDisc && isPtrauthRegSafe(AddrDisc)) {
ScratchReg = AddrDisc;
} else {
emitMovXReg(ScratchReg, AddrDisc);
assert(ScratchReg != AddrDisc &&
"Forbidden to clobber AddrDisc, but have to");
}
emitMOVK(ScratchReg, Disc, 48);
return ScratchReg;
}
/// Emit a code sequence to check an authenticated pointer value.
///
/// This function emits a sequence of instructions that checks if TestedReg was
/// authenticated successfully. On success, execution continues at the next
/// instruction after the sequence.
///
/// The action performed on failure depends on the OnFailure argument:
/// * if OnFailure is not nullptr, control is transferred to that label after
/// clearing the PAC field
/// * otherwise, BRK instruction is emitted to generate an error
void AArch64AsmPrinter::emitPtrauthCheckAuthenticatedValue(
Register TestedReg, Register ScratchReg, AArch64PACKey::ID Key,
AArch64PAuth::AuthCheckMethod Method, const MCSymbol *OnFailure) {
// Insert a sequence to check if authentication of TestedReg succeeded,
// such as:
//
// - checked and clearing:
// ; x16 is TestedReg, x17 is ScratchReg
// mov x17, x16
// xpaci x17
// cmp x16, x17
// b.eq Lsuccess
// mov x16, x17
// b Lend
// Lsuccess:
// ; skipped if authentication failed
// Lend:
// ...
//
// - checked and trapping:
// mov x17, x16
// xpaci x17
// cmp x16, x17
// b.eq Lsuccess
// brk #<0xc470 + aut key>
// Lsuccess:
// ...
//
// See the documentation on AuthCheckMethod enumeration constants for
// the specific code sequences that can be used to perform the check.
using AArch64PAuth::AuthCheckMethod;
if (Method == AuthCheckMethod::None)
return;
if (Method == AuthCheckMethod::DummyLoad) {
EmitToStreamer(MCInstBuilder(AArch64::LDRWui)
.addReg(getWRegFromXReg(ScratchReg))
.addReg(TestedReg)
.addImm(0));
assert(!OnFailure && "DummyLoad always traps on error");
return;
}
MCSymbol *SuccessSym = createTempSymbol("auth_success_");
if (Method == AuthCheckMethod::XPAC || Method == AuthCheckMethod::XPACHint) {
// mov Xscratch, Xtested
emitMovXReg(ScratchReg, TestedReg);
if (Method == AuthCheckMethod::XPAC) {
// xpac(i|d) Xscratch
unsigned XPACOpc = getXPACOpcodeForKey(Key);
EmitToStreamer(
MCInstBuilder(XPACOpc).addReg(ScratchReg).addReg(ScratchReg));
} else {
// xpaclri
// Note that this method applies XPAC to TestedReg instead of ScratchReg.
assert(TestedReg == AArch64::LR &&
"XPACHint mode is only compatible with checking the LR register");
assert((Key == AArch64PACKey::IA || Key == AArch64PACKey::IB) &&
"XPACHint mode is only compatible with I-keys");
EmitToStreamer(MCInstBuilder(AArch64::XPACLRI));
}
// cmp Xtested, Xscratch
EmitToStreamer(MCInstBuilder(AArch64::SUBSXrs)
.addReg(AArch64::XZR)
.addReg(TestedReg)
.addReg(ScratchReg)
.addImm(0));
// b.eq Lsuccess
EmitToStreamer(
MCInstBuilder(AArch64::Bcc)
.addImm(AArch64CC::EQ)
.addExpr(MCSymbolRefExpr::create(SuccessSym, OutContext)));
} else if (Method == AuthCheckMethod::HighBitsNoTBI) {
// eor Xscratch, Xtested, Xtested, lsl #1
EmitToStreamer(MCInstBuilder(AArch64::EORXrs)
.addReg(ScratchReg)
.addReg(TestedReg)
.addReg(TestedReg)
.addImm(1));
// tbz Xscratch, #62, Lsuccess
EmitToStreamer(
MCInstBuilder(AArch64::TBZX)
.addReg(ScratchReg)
.addImm(62)
.addExpr(MCSymbolRefExpr::create(SuccessSym, OutContext)));
} else {
llvm_unreachable("Unsupported check method");
}
if (!OnFailure) {
// Trapping sequences do a 'brk'.
// brk #<0xc470 + aut key>
EmitToStreamer(MCInstBuilder(AArch64::BRK).addImm(0xc470 | Key));
} else {
// Non-trapping checked sequences return the stripped result in TestedReg,
// skipping over success-only code (such as re-signing the pointer) by
// jumping to OnFailure label.
// Note that this can introduce an authentication oracle (such as based on
// the high bits of the re-signed value).
// FIXME: The XPAC method can be optimized by applying XPAC to TestedReg
// instead of ScratchReg, thus eliminating one `mov` instruction.
// Both XPAC and XPACHint can be further optimized by not using a
// conditional branch jumping over an unconditional one.
switch (Method) {
case AuthCheckMethod::XPACHint:
// LR is already XPAC-ed at this point.
break;
case AuthCheckMethod::XPAC:
// mov Xtested, Xscratch
emitMovXReg(TestedReg, ScratchReg);
break;
default:
// If Xtested was not XPAC-ed so far, emit XPAC here.
// xpac(i|d) Xtested
unsigned XPACOpc = getXPACOpcodeForKey(Key);
EmitToStreamer(
MCInstBuilder(XPACOpc).addReg(TestedReg).addReg(TestedReg));
}
// b Lend
const auto *OnFailureExpr = MCSymbolRefExpr::create(OnFailure, OutContext);
EmitToStreamer(MCInstBuilder(AArch64::B).addExpr(OnFailureExpr));
}
// If the auth check succeeds, we can continue.
// Lsuccess:
OutStreamer->emitLabel(SuccessSym);
}
// With Pointer Authentication, it may be needed to explicitly check the
// authenticated value in LR before performing a tail call.
// Otherwise, the callee may re-sign the invalid return address,
// introducing a signing oracle.
void AArch64AsmPrinter::emitPtrauthTailCallHardening(const MachineInstr *TC) {
if (!AArch64FI->shouldSignReturnAddress(*MF))
return;
auto LRCheckMethod = STI->getAuthenticatedLRCheckMethod(*MF);
if (LRCheckMethod == AArch64PAuth::AuthCheckMethod::None)
return;
const AArch64RegisterInfo *TRI = STI->getRegisterInfo();
Register ScratchReg =
TC->readsRegister(AArch64::X16, TRI) ? AArch64::X17 : AArch64::X16;
assert(!TC->readsRegister(ScratchReg, TRI) &&
"Neither x16 nor x17 is available as a scratch register");
AArch64PACKey::ID Key =
AArch64FI->shouldSignWithBKey() ? AArch64PACKey::IB : AArch64PACKey::IA;
emitPtrauthCheckAuthenticatedValue(AArch64::LR, ScratchReg, Key,
LRCheckMethod);
}
bool AArch64AsmPrinter::emitDeactivationSymbolRelocation(Value *DS) {
if (!DS)
return false;
if (isa<GlobalAlias>(DS)) {
// Just emit the nop directly.
EmitToStreamer(MCInstBuilder(AArch64::NOP));
return true;
}
MCSymbol *Dot = OutContext.createTempSymbol();
OutStreamer->emitLabel(Dot);
const MCExpr *DeactDotExpr = MCSymbolRefExpr::create(Dot, OutContext);
const MCExpr *DSExpr = MCSymbolRefExpr::create(
OutContext.getOrCreateSymbol(DS->getName()), OutContext);
OutStreamer->emitRelocDirective(*DeactDotExpr, "R_AARCH64_PATCHINST", DSExpr,
SMLoc());
return false;
}
AArch64AsmPrinter::PtrAuthSchema::PtrAuthSchema(
AArch64PACKey::ID Key, uint64_t IntDisc, const MachineOperand &AddrDiscOp)
: Key(Key), IntDisc(IntDisc), AddrDisc(AddrDiscOp.getReg()),
AddrDiscIsKilled(AddrDiscOp.isKill()) {}
void AArch64AsmPrinter::emitPtrauthAuthResign(
Register Pointer, Register Scratch, PtrAuthSchema AuthSchema,
std::optional<PtrAuthSchema> SignSchema, std::optional<uint64_t> OptAddend,
Value *DS) {
const bool IsResign = SignSchema.has_value();
const bool HasLoad = OptAddend.has_value();
// We expand AUT/AUTPAC into a sequence of the form
//
// ; authenticate x16
// ; check pointer in x16
// Lsuccess:
// ; sign x16 (if AUTPAC)
// Lend: ; if not trapping on failure
//
// with the checking sequence chosen depending on whether/how we should check
// the pointer and whether we should trap on failure.
// By default, auth/resign sequences check for auth failures.
bool ShouldCheck = true;
// In the checked sequence, we only trap if explicitly requested.
bool ShouldTrap = MF->getFunction().hasFnAttribute("ptrauth-auth-traps");
// On an FPAC CPU, you get traps whether you want them or not: there's
// no point in emitting checks or traps.
if (STI->hasFPAC())
ShouldCheck = ShouldTrap = false;
// However, command-line flags can override this, for experimentation.
switch (PtrauthAuthChecks) {
case PtrauthCheckMode::Default:
break;
case PtrauthCheckMode::Unchecked:
ShouldCheck = ShouldTrap = false;
break;
case PtrauthCheckMode::Poison:
ShouldCheck = true;
ShouldTrap = false;
break;
case PtrauthCheckMode::Trap:
ShouldCheck = ShouldTrap = true;
break;
}
// Compute aut discriminator
Register AUTDiscReg =
emitPtrauthDiscriminator(AuthSchema.IntDisc, AuthSchema.AddrDisc, Scratch,
AuthSchema.AddrDiscIsKilled);
if (!emitDeactivationSymbolRelocation(DS))
emitAUT(AuthSchema.Key, Pointer, AUTDiscReg);
// Unchecked or checked-but-non-trapping AUT is just an "AUT": we're done.
if (!IsResign && (!ShouldCheck || !ShouldTrap))
return;
MCSymbol *EndSym = nullptr;
if (ShouldCheck) {
if (IsResign && !ShouldTrap)
EndSym = createTempSymbol("resign_end_");
emitPtrauthCheckAuthenticatedValue(Pointer, Scratch, AuthSchema.Key,
AArch64PAuth::AuthCheckMethod::XPAC,
EndSym);
}
// We already emitted unchecked and checked-but-non-trapping AUTs.
// That left us with trapping AUTs, and AUTPA/AUTRELLOADPACs.
// Trapping AUTs don't need PAC: we're done.
if (!IsResign)
return;
if (HasLoad) {
int64_t Addend = *OptAddend;
// incoming rawpointer in X16, X17 is not live at this point.
// LDSRWpre x17, x16, simm9 ; note: x16+simm9 used later.
if (isInt<9>(Addend)) {
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::LDRSWpre)
.addReg(AArch64::X16)
.addReg(AArch64::X17)
.addReg(AArch64::X16)
.addImm(/*simm9:*/ Addend));
} else {
// x16 = x16 + Addend computation has 2 variants
if (isUInt<24>(Addend)) {
// variant 1: add x16, x16, Addend >> shift12 ls shift12
// This can take upto 2 instructions.
for (int BitPos = 0; BitPos != 24 && (Addend >> BitPos); BitPos += 12) {
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::ADDXri)
.addReg(AArch64::X16)
.addReg(AArch64::X16)
.addImm((Addend >> BitPos) & 0xfff)
.addImm(AArch64_AM::getShifterImm(
AArch64_AM::LSL, BitPos)));
}
} else {
// variant 2: accumulate constant in X17 16 bits at a time, and add to
// X16 This can take 2-5 instructions.
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::MOVZXi)
.addReg(AArch64::X17)
.addImm(Addend & 0xffff)
.addImm(AArch64_AM::getShifterImm(
AArch64_AM::LSL, 0)));
for (int Offset = 16; Offset < 64; Offset += 16) {
uint16_t Fragment = static_cast<uint16_t>(Addend >> Offset);
if (!Fragment)
continue;
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::MOVKXi)
.addReg(AArch64::X17)
.addReg(AArch64::X17)
.addImm(Fragment)
.addImm(/*shift:*/ Offset));
}
// addx x16, x16, x17
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::ADDXrs)
.addReg(AArch64::X16)
.addReg(AArch64::X16)
.addReg(AArch64::X17)
.addImm(0));
}
// ldrsw x17,x16(0)
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::LDRSWui)
.addReg(AArch64::X17)
.addReg(AArch64::X16)
.addImm(0));
}
// addx x16, x16, x17
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::ADDXrs)
.addReg(AArch64::X16)
.addReg(AArch64::X16)
.addReg(AArch64::X17)
.addImm(0));
} /* HasLoad == true */
// Compute pac discriminator into x17
Register PACDiscReg = emitPtrauthDiscriminator(SignSchema->IntDisc,
SignSchema->AddrDisc, Scratch);
emitPAC(SignSchema->Key, Pointer, PACDiscReg);
// Lend:
if (EndSym)
OutStreamer->emitLabel(EndSym);
}
void AArch64AsmPrinter::emitPtrauthSign(const MachineInstr *MI) {
Register Val = MI->getOperand(1).getReg();
auto Key = (AArch64PACKey::ID)MI->getOperand(2).getImm();
uint64_t Disc = MI->getOperand(3).getImm();
Register AddrDisc = MI->getOperand(4).getReg();
bool AddrDiscKilled = MI->getOperand(4).isKill();
// As long as at least one of Val and AddrDisc is in GPR64noip, a scratch
// register is available.
Register ScratchReg = Val == AArch64::X16 ? AArch64::X17 : AArch64::X16;
assert(ScratchReg != AddrDisc &&
"Neither X16 nor X17 is available as a scratch register");
// Compute pac discriminator
Register DiscReg = emitPtrauthDiscriminator(
Disc, AddrDisc, ScratchReg, /*MayClobberAddrDisc=*/AddrDiscKilled);
if (emitDeactivationSymbolRelocation(MI->getDeactivationSymbol()))
return;
emitPAC(Key, Val, DiscReg);
}
void AArch64AsmPrinter::emitPtrauthBranch(const MachineInstr *MI) {
bool IsCall = MI->getOpcode() == AArch64::BLRA;
unsigned BrTarget = MI->getOperand(0).getReg();
auto Key = (AArch64PACKey::ID)MI->getOperand(1).getImm();
uint64_t Disc = MI->getOperand(2).getImm();
unsigned AddrDisc = MI->getOperand(3).getReg();
// Make sure AddrDisc is solely used to compute the discriminator.
// While hardly meaningful, it is still possible to describe an authentication
// of a pointer against its own value (instead of storage address) with
// intrinsics, so use report_fatal_error instead of assert.
if (BrTarget == AddrDisc)
report_fatal_error("Branch target is signed with its own value");
// If we are printing BLRA pseudo, try to save one MOV by making use of the
// fact that x16 and x17 are described as clobbered by the MI instruction and
// AddrDisc is not used as any other input.
//
// Back in the day, emitPtrauthDiscriminator was restricted to only returning
// either x16 or x17, meaning the returned register is always among the
// implicit-def'ed registers of BLRA pseudo. Now this property can be violated
// if isX16X17Safer predicate is false, thus manually check if AddrDisc is
// among x16 and x17 to prevent clobbering unexpected registers.
//
// Unlike BLRA, BRA pseudo is used to perform computed goto, and thus not
// declared as clobbering x16/x17.
//
// FIXME: Make use of `killed` flags and register masks instead.
bool AddrDiscIsImplicitDef =
IsCall && (AddrDisc == AArch64::X16 || AddrDisc == AArch64::X17);
Register DiscReg = emitPtrauthDiscriminator(Disc, AddrDisc, AArch64::X17,
AddrDiscIsImplicitDef);
emitBLRA(IsCall, Key, BrTarget, DiscReg);
}
void AArch64AsmPrinter::emitAddImm(MCRegister Reg, int64_t Addend,
MCRegister Tmp) {
if (Addend != 0) {
const uint64_t AbsOffset = (Addend > 0 ? Addend : -((uint64_t)Addend));
const bool IsNeg = Addend < 0;
if (isUInt<24>(AbsOffset)) {
for (int BitPos = 0; BitPos != 24 && (AbsOffset >> BitPos);
BitPos += 12) {
EmitToStreamer(
MCInstBuilder(IsNeg ? AArch64::SUBXri : AArch64::ADDXri)
.addReg(Reg)
.addReg(Reg)
.addImm((AbsOffset >> BitPos) & 0xfff)
.addImm(AArch64_AM::getShifterImm(AArch64_AM::LSL, BitPos)));
}
} else {
const uint64_t UAddend = Addend;
EmitToStreamer(MCInstBuilder(IsNeg ? AArch64::MOVNXi : AArch64::MOVZXi)
.addReg(Tmp)
.addImm((IsNeg ? ~UAddend : UAddend) & 0xffff)
.addImm(/*shift=*/0));
auto NeedMovk = [IsNeg, UAddend](int BitPos) -> bool {
assert(BitPos == 16 || BitPos == 32 || BitPos == 48);
uint64_t Shifted = UAddend >> BitPos;
if (!IsNeg)
return Shifted != 0;
for (int I = 0; I != 64 - BitPos; I += 16)
if (((Shifted >> I) & 0xffff) != 0xffff)
return true;
return false;
};
for (int BitPos = 16; BitPos != 64 && NeedMovk(BitPos); BitPos += 16)
emitMOVK(Tmp, (UAddend >> BitPos) & 0xffff, BitPos);
EmitToStreamer(MCInstBuilder(AArch64::ADDXrs)
.addReg(Reg)
.addReg(Reg)
.addReg(Tmp)
.addImm(/*shift=*/0));
}
}
}
void AArch64AsmPrinter::emitAddress(MCRegister Reg, const MCExpr *Expr,
MCRegister Tmp, bool DSOLocal,
const MCSubtargetInfo &STI) {
MCValue Val;
if (!Expr->evaluateAsRelocatable(Val, nullptr))
report_fatal_error("emitAddress could not evaluate");
if (DSOLocal) {
EmitToStreamer(
MCInstBuilder(AArch64::ADRP)
.addReg(Reg)
.addExpr(MCSpecifierExpr::create(Expr, AArch64::S_ABS_PAGE,
OutStreamer->getContext())));
EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
.addReg(Reg)
.addReg(Reg)
.addExpr(MCSpecifierExpr::create(
Expr, AArch64::S_LO12, OutStreamer->getContext()))
.addImm(0));
} else {
auto *SymRef =
MCSymbolRefExpr::create(Val.getAddSym(), OutStreamer->getContext());
EmitToStreamer(
MCInstBuilder(AArch64::ADRP)
.addReg(Reg)
.addExpr(MCSpecifierExpr::create(SymRef, AArch64::S_GOT_PAGE,
OutStreamer->getContext())));
EmitToStreamer(
MCInstBuilder(AArch64::LDRXui)
.addReg(Reg)
.addReg(Reg)
.addExpr(MCSpecifierExpr::create(SymRef, AArch64::S_GOT_LO12,
OutStreamer->getContext())));
emitAddImm(Reg, Val.getConstant(), Tmp);
}
}
static bool targetSupportsIRelativeRelocation(const Triple &TT) {
// IFUNCs are ELF-only.
if (!TT.isOSBinFormatELF())
return false;
// IFUNCs are supported on glibc, bionic, and some but not all of the BSDs.
return TT.isOSGlibc() || TT.isAndroid() || TT.isOSFreeBSD() ||
TT.isOSDragonFly() || TT.isOSNetBSD();
}
// Emit an ifunc resolver that returns a signed pointer to the specified target,
// and return a FUNCINIT reference to the resolver. In the linked binary, this
// function becomes the target of an IRELATIVE relocation. This resolver is used
// to relocate signed pointers in global variable initializers in special cases
// where the standard R_AARCH64_AUTH_ABS64 relocation would not work.
//
// Example (signed null pointer, not address discriminated):
//
// .8byte .Lpauth_ifunc0
// .pushsection .text.startup,"ax",@progbits
// .Lpauth_ifunc0:
// mov x0, #0
// mov x1, #12345
// b __emupac_pacda
//
// Example (signed null pointer, address discriminated):
//
// .Ltmp:
// .8byte .Lpauth_ifunc0
// .pushsection .text.startup,"ax",@progbits
// .Lpauth_ifunc0:
// mov x0, #0
// adrp x1, .Ltmp
// add x1, x1, :lo12:.Ltmp
// b __emupac_pacda
// .popsection
//
// Example (signed pointer to symbol, not address discriminated):
//
// .Ltmp:
// .8byte .Lpauth_ifunc0
// .pushsection .text.startup,"ax",@progbits
// .Lpauth_ifunc0:
// adrp x0, symbol
// add x0, x0, :lo12:symbol
// mov x1, #12345
// b __emupac_pacda
// .popsection
//
// Example (signed null pointer, not address discriminated, with deactivation
// symbol ds):
//
// .8byte .Lpauth_ifunc0
// .pushsection .text.startup,"ax",@progbits
// .Lpauth_ifunc0:
// mov x0, #0
// mov x1, #12345
// .reloc ., R_AARCH64_PATCHINST, ds
// b __emupac_pacda
// ret
// .popsection
const MCExpr *AArch64AsmPrinter::emitPAuthRelocationAsIRelative(
const MCExpr *Target, uint64_t Disc, AArch64PACKey::ID KeyID,
bool HasAddressDiversity, bool IsDSOLocal, const MCExpr *DSExpr) {
const Triple &TT = TM.getTargetTriple();
// We only emit an IRELATIVE relocation if the target supports IRELATIVE.
if (!targetSupportsIRelativeRelocation(TT))
return nullptr;
// For now, only the DA key is supported.
if (KeyID != AArch64PACKey::DA)
return nullptr;
// AArch64Subtarget is huge, so heap allocate it so we don't run out of stack
// space.
auto STI = std::make_unique<AArch64Subtarget>(
TT, TM.getTargetCPU(), TM.getTargetCPU(), TM.getTargetFeatureString(), TM,
true);
this->STI = STI.get();
MCSymbol *Place = OutStreamer->getContext().createTempSymbol();
OutStreamer->emitLabel(Place);
OutStreamer->pushSection();
const MCSymbolELF *Group =
static_cast<MCSectionELF *>(OutStreamer->getCurrentSectionOnly())
->getGroup();
auto Flags = ELF::SHF_ALLOC | ELF::SHF_EXECINSTR;
if (Group)
Flags |= ELF::SHF_GROUP;
OutStreamer->switchSection(OutStreamer->getContext().getELFSection(
".text.startup", ELF::SHT_PROGBITS, Flags, 0, Group, true,
Group ? MCSection::NonUniqueID : PAuthIFuncNextUniqueID++, nullptr));
MCSymbol *IRelativeSym =
OutStreamer->getContext().createLinkerPrivateSymbol("pauth_ifunc");
OutStreamer->emitLabel(IRelativeSym);
if (isa<MCConstantExpr>(Target)) {
OutStreamer->emitInstruction(MCInstBuilder(AArch64::MOVZXi)
.addReg(AArch64::X0)
.addExpr(Target)
.addImm(0),
*STI);
} else {
emitAddress(AArch64::X0, Target, AArch64::X16, IsDSOLocal, *STI);
}
if (HasAddressDiversity) {
auto *PlacePlusDisc = MCBinaryExpr::createAdd(
MCSymbolRefExpr::create(Place, OutStreamer->getContext()),
MCConstantExpr::create(Disc, OutStreamer->getContext()),
OutStreamer->getContext());
emitAddress(AArch64::X1, PlacePlusDisc, AArch64::X16, /*IsDSOLocal=*/true,
*STI);
} else {
if (!isUInt<16>(Disc)) {
OutContext.reportError(SMLoc(), "AArch64 PAC Discriminator '" +
Twine(Disc) +
"' out of range [0, 0xFFFF]");
}
emitMOVZ(AArch64::X1, Disc, 0);
}
if (DSExpr) {
MCSymbol *PrePACInst = OutStreamer->getContext().createTempSymbol();
OutStreamer->emitLabel(PrePACInst);
auto *PrePACInstExpr =
MCSymbolRefExpr::create(PrePACInst, OutStreamer->getContext());
OutStreamer->emitRelocDirective(*PrePACInstExpr, "R_AARCH64_PATCHINST",
DSExpr, SMLoc());
}
// We don't know the subtarget because this is being emitted for a global
// initializer. Because the performance of IFUNC resolvers is unimportant, we
// always call the EmuPAC runtime, which will end up using the PAC instruction
// if the target supports PAC.
MCSymbol *EmuPAC =
OutStreamer->getContext().getOrCreateSymbol("__emupac_pacda");
const MCSymbolRefExpr *EmuPACRef =
MCSymbolRefExpr::create(EmuPAC, OutStreamer->getContext());
OutStreamer->emitInstruction(MCInstBuilder(AArch64::B).addExpr(EmuPACRef),
*STI);
// We need a RET despite the above tail call because the deactivation symbol
// may replace the tail call with a NOP.
if (DSExpr)
OutStreamer->emitInstruction(
MCInstBuilder(AArch64::RET).addReg(AArch64::LR), *STI);
OutStreamer->popSection();
return MCSymbolRefExpr::create(IRelativeSym, AArch64::S_FUNCINIT,
OutStreamer->getContext());
}
const MCExpr *
AArch64AsmPrinter::lowerConstantPtrAuth(const ConstantPtrAuth &CPA) {
MCContext &Ctx = OutContext;
// Figure out the base symbol and the addend, if any.
APInt Offset(64, 0);
const Value *BaseGV = CPA.getPointer()->stripAndAccumulateConstantOffsets(
getDataLayout(), Offset, /*AllowNonInbounds=*/true);
auto *BaseGVB = dyn_cast<GlobalValue>(BaseGV);
const MCExpr *Sym;
if (BaseGVB) {
// If there is an addend, turn that into the appropriate MCExpr.
Sym = MCSymbolRefExpr::create(getSymbol(BaseGVB), Ctx);
if (Offset.sgt(0))
Sym = MCBinaryExpr::createAdd(
Sym, MCConstantExpr::create(Offset.getSExtValue(), Ctx), Ctx);
else if (Offset.slt(0))
Sym = MCBinaryExpr::createSub(
Sym, MCConstantExpr::create((-Offset).getSExtValue(), Ctx), Ctx);
} else {
Sym = MCConstantExpr::create(Offset.getSExtValue(), Ctx);
}
const MCExpr *DSExpr = nullptr;
if (auto *DS = dyn_cast<GlobalValue>(CPA.getDeactivationSymbol())) {
if (isa<GlobalAlias>(DS))
return Sym;
DSExpr = MCSymbolRefExpr::create(getSymbol(DS), Ctx);
}
uint64_t KeyID = CPA.getKey()->getZExtValue();
// We later rely on valid KeyID value in AArch64PACKeyIDToString call from
// AArch64AuthMCExpr::printImpl, so fail fast.
if (KeyID > AArch64PACKey::LAST) {
CPA.getContext().emitError("AArch64 PAC Key ID '" + Twine(KeyID) +
"' out of range [0, " +
Twine((unsigned)AArch64PACKey::LAST) + "]");
KeyID = 0;
}
uint64_t Disc = CPA.getDiscriminator()->getZExtValue();
// Check if we can represent this with an IRELATIVE and emit it if so.
if (auto *IFuncSym = emitPAuthRelocationAsIRelative(
Sym, Disc, AArch64PACKey::ID(KeyID), CPA.hasAddressDiscriminator(),
BaseGVB && BaseGVB->isDSOLocal(), DSExpr))
return IFuncSym;
if (!isUInt<16>(Disc)) {
CPA.getContext().emitError("AArch64 PAC Discriminator '" + Twine(Disc) +
"' out of range [0, 0xFFFF]");
Disc = 0;
}
if (DSExpr)
report_fatal_error("deactivation symbols unsupported in constant "
"expressions on this target");
// Finally build the complete @AUTH expr.
return AArch64AuthMCExpr::create(Sym, Disc, AArch64PACKey::ID(KeyID),
CPA.hasAddressDiscriminator(), Ctx);
}
void AArch64AsmPrinter::LowerLOADauthptrstatic(const MachineInstr &MI) {
unsigned DstReg = MI.getOperand(0).getReg();
const MachineOperand &GAOp = MI.getOperand(1);
const uint64_t KeyC = MI.getOperand(2).getImm();
assert(KeyC <= AArch64PACKey::LAST &&
"key is out of range [0, AArch64PACKey::LAST]");
const auto Key = (AArch64PACKey::ID)KeyC;
const uint64_t Disc = MI.getOperand(3).getImm();
assert(isUInt<16>(Disc) &&
"constant discriminator is out of range [0, 0xffff]");
// Emit instruction sequence like the following:
// ADRP x16, symbol$auth_ptr$key$disc
// LDR x16, [x16, :lo12:symbol$auth_ptr$key$disc]
//
// Where the $auth_ptr$ symbol is the stub slot containing the signed pointer
// to symbol.
MCSymbol *AuthPtrStubSym;
if (TM.getTargetTriple().isOSBinFormatELF()) {
const auto &TLOF =
static_cast<const AArch64_ELFTargetObjectFile &>(getObjFileLowering());
assert(GAOp.getOffset() == 0 &&
"non-zero offset for $auth_ptr$ stub slots is not supported");
const MCSymbol *GASym = TM.getSymbol(GAOp.getGlobal());
AuthPtrStubSym = TLOF.getAuthPtrSlotSymbol(TM, MMI, GASym, Key, Disc);
} else {
assert(TM.getTargetTriple().isOSBinFormatMachO() &&
"LOADauthptrstatic is implemented only for MachO/ELF");
const auto &TLOF = static_cast<const AArch64_MachoTargetObjectFile &>(
getObjFileLowering());
assert(GAOp.getOffset() == 0 &&
"non-zero offset for $auth_ptr$ stub slots is not supported");
const MCSymbol *GASym = TM.getSymbol(GAOp.getGlobal());
AuthPtrStubSym = TLOF.getAuthPtrSlotSymbol(TM, MMI, GASym, Key, Disc);
}
MachineOperand StubMOHi =
MachineOperand::CreateMCSymbol(AuthPtrStubSym, AArch64II::MO_PAGE);
MachineOperand StubMOLo = MachineOperand::CreateMCSymbol(
AuthPtrStubSym, AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
MCOperand StubMCHi, StubMCLo;
MCInstLowering.lowerOperand(StubMOHi, StubMCHi);
MCInstLowering.lowerOperand(StubMOLo, StubMCLo);
EmitToStreamer(
*OutStreamer,
MCInstBuilder(AArch64::ADRP).addReg(DstReg).addOperand(StubMCHi));
EmitToStreamer(*OutStreamer, MCInstBuilder(AArch64::LDRXui)
.addReg(DstReg)
.addReg(DstReg)
.addOperand(StubMCLo));
}
void AArch64AsmPrinter::LowerMOVaddrPAC(const MachineInstr &MI) {
const bool IsGOTLoad = MI.getOpcode() == AArch64::LOADgotPAC;
const bool IsELFSignedGOT = MI.getParent()
->getParent()
->getInfo<AArch64FunctionInfo>()
->hasELFSignedGOT();
MachineOperand GAOp = MI.getOperand(0);
const uint64_t KeyC = MI.getOperand(1).getImm();
assert(KeyC <= AArch64PACKey::LAST &&
"key is out of range [0, AArch64PACKey::LAST]");
const auto Key = (AArch64PACKey::ID)KeyC;
const unsigned AddrDisc = MI.getOperand(2).getReg();
const uint64_t Disc = MI.getOperand(3).getImm();
const int64_t Offset = GAOp.getOffset();
GAOp.setOffset(0);
// Emit:
// target materialization:
// - via GOT:
// - unsigned GOT:
// adrp x16, :got:target
// ldr x16, [x16, :got_lo12:target]
// add offset to x16 if offset != 0
// - ELF signed GOT:
// adrp x17, :got:target
// add x17, x17, :got_auth_lo12:target
// ldr x16, [x17]
// aut{i|d}a x16, x17
// check+trap sequence (if no FPAC)
// add offset to x16 if offset != 0
//
// - direct:
// adrp x16, target
// add x16, x16, :lo12:target
// add offset to x16 if offset != 0
//
// add offset to x16:
// - abs(offset) fits 24 bits:
// add/sub x16, x16, #<offset>[, #lsl 12] (up to 2 instructions)
// - abs(offset) does not fit 24 bits:
// - offset < 0:
// movn+movk sequence filling x17 register with the offset (up to 4
// instructions)
// add x16, x16, x17
// - offset > 0:
// movz+movk sequence filling x17 register with the offset (up to 4
// instructions)
// add x16, x16, x17
//
// signing:
// - 0 discriminator:
// paciza x16
// - Non-0 discriminator, no address discriminator:
// mov x17, #Disc
// pacia x16, x17
// - address discriminator (with potentially folded immediate discriminator):
// pacia x16, xAddrDisc
MachineOperand GAMOHi(GAOp), GAMOLo(GAOp);
MCOperand GAMCHi, GAMCLo;
GAMOHi.setTargetFlags(AArch64II::MO_PAGE);
GAMOLo.setTargetFlags(AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
if (IsGOTLoad) {
GAMOHi.addTargetFlag(AArch64II::MO_GOT);
GAMOLo.addTargetFlag(AArch64II::MO_GOT);
}
MCInstLowering.lowerOperand(GAMOHi, GAMCHi);
MCInstLowering.lowerOperand(GAMOLo, GAMCLo);
EmitToStreamer(
MCInstBuilder(AArch64::ADRP)
.addReg(IsGOTLoad && IsELFSignedGOT ? AArch64::X17 : AArch64::X16)
.addOperand(GAMCHi));
if (IsGOTLoad) {
if (IsELFSignedGOT) {
EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
.addReg(AArch64::X17)
.addReg(AArch64::X17)
.addOperand(GAMCLo)
.addImm(0));
EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
.addReg(AArch64::X16)
.addReg(AArch64::X17)
.addImm(0));
assert(GAOp.isGlobal());
assert(GAOp.getGlobal()->getValueType() != nullptr);
bool IsFunctionTy = GAOp.getGlobal()->getValueType()->isFunctionTy();
auto AuthKey = IsFunctionTy ? AArch64PACKey::IA : AArch64PACKey::DA;
emitAUT(AuthKey, AArch64::X16, AArch64::X17);
if (!STI->hasFPAC())
emitPtrauthCheckAuthenticatedValue(AArch64::X16, AArch64::X17, AuthKey,
AArch64PAuth::AuthCheckMethod::XPAC);
} else {
EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
.addReg(AArch64::X16)
.addReg(AArch64::X16)
.addOperand(GAMCLo));
}
} else {
EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
.addReg(AArch64::X16)
.addReg(AArch64::X16)
.addOperand(GAMCLo)
.addImm(0));
}
emitAddImm(AArch64::X16, Offset, AArch64::X17);
Register DiscReg = emitPtrauthDiscriminator(Disc, AddrDisc, AArch64::X17);
emitPAC(Key, AArch64::X16, DiscReg);
}
void AArch64AsmPrinter::LowerLOADgotAUTH(const MachineInstr &MI) {
Register DstReg = MI.getOperand(0).getReg();
Register AuthResultReg = STI->hasFPAC() ? DstReg : AArch64::X16;
const MachineOperand &GAMO = MI.getOperand(1);
assert(GAMO.getOffset() == 0);
if (MI.getMF()->getTarget().getCodeModel() == CodeModel::Tiny) {
MCOperand GAMC;
MCInstLowering.lowerOperand(GAMO, GAMC);
EmitToStreamer(
MCInstBuilder(AArch64::ADR).addReg(AArch64::X17).addOperand(GAMC));
EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
.addReg(AuthResultReg)
.addReg(AArch64::X17)
.addImm(0));
} else {
MachineOperand GAHiOp(GAMO);
MachineOperand GALoOp(GAMO);
GAHiOp.addTargetFlag(AArch64II::MO_PAGE);
GALoOp.addTargetFlag(AArch64II::MO_PAGEOFF | AArch64II::MO_NC);
MCOperand GAMCHi, GAMCLo;
MCInstLowering.lowerOperand(GAHiOp, GAMCHi);
MCInstLowering.lowerOperand(GALoOp, GAMCLo);
EmitToStreamer(
MCInstBuilder(AArch64::ADRP).addReg(AArch64::X17).addOperand(GAMCHi));
EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
.addReg(AArch64::X17)
.addReg(AArch64::X17)
.addOperand(GAMCLo)
.addImm(0));
EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
.addReg(AuthResultReg)
.addReg(AArch64::X17)
.addImm(0));
}
assert(GAMO.isGlobal());
MCSymbol *UndefWeakSym;
if (GAMO.getGlobal()->hasExternalWeakLinkage()) {
UndefWeakSym = createTempSymbol("undef_weak");
EmitToStreamer(
MCInstBuilder(AArch64::CBZX)
.addReg(AuthResultReg)
.addExpr(MCSymbolRefExpr::create(UndefWeakSym, OutContext)));
}
assert(GAMO.getGlobal()->getValueType() != nullptr);
bool IsFunctionTy = GAMO.getGlobal()->getValueType()->isFunctionTy();
auto AuthKey = IsFunctionTy ? AArch64PACKey::IA : AArch64PACKey::DA;
emitAUT(AuthKey, AuthResultReg, AArch64::X17);
if (GAMO.getGlobal()->hasExternalWeakLinkage())
OutStreamer->emitLabel(UndefWeakSym);
if (!STI->hasFPAC()) {
emitPtrauthCheckAuthenticatedValue(AuthResultReg, AArch64::X17, AuthKey,
AArch64PAuth::AuthCheckMethod::XPAC);
emitMovXReg(DstReg, AuthResultReg);
}
}
const MCExpr *
AArch64AsmPrinter::lowerBlockAddressConstant(const BlockAddress &BA) {
const MCExpr *BAE = AsmPrinter::lowerBlockAddressConstant(BA);
const Function &Fn = *BA.getFunction();
if (std::optional<uint16_t> BADisc =
STI->getPtrAuthBlockAddressDiscriminatorIfEnabled(Fn))
return AArch64AuthMCExpr::create(BAE, *BADisc, AArch64PACKey::IA,
/*HasAddressDiversity=*/false, OutContext);
return BAE;
}
void AArch64AsmPrinter::emitCBPseudoExpansion(const MachineInstr *MI) {
bool IsImm = false;
unsigned Width = 0;
switch (MI->getOpcode()) {
default:
llvm_unreachable("This is not a CB pseudo instruction");
case AArch64::CBBAssertExt:
IsImm = false;
Width = 8;
break;
case AArch64::CBHAssertExt:
IsImm = false;
Width = 16;
break;
case AArch64::CBWPrr:
Width = 32;
break;
case AArch64::CBXPrr:
Width = 64;
break;
case AArch64::CBWPri:
IsImm = true;
Width = 32;
break;
case AArch64::CBXPri:
IsImm = true;
Width = 64;
break;
}
AArch64CC::CondCode CC =
static_cast<AArch64CC::CondCode>(MI->getOperand(0).getImm());
bool NeedsRegSwap = false;
bool NeedsImmDec = false;
bool NeedsImmInc = false;
#define GET_CB_OPC(IsImm, Width, ImmCond, RegCond) \
(IsImm \
? (Width == 32 ? AArch64::CB##ImmCond##Wri : AArch64::CB##ImmCond##Xri) \
: (Width == 8 \
? AArch64::CBB##RegCond##Wrr \
: (Width == 16 ? AArch64::CBH##RegCond##Wrr \
: (Width == 32 ? AArch64::CB##RegCond##Wrr \
: AArch64::CB##RegCond##Xrr))))
unsigned MCOpC;
// Decide if we need to either swap register operands or increment/decrement
// immediate operands
switch (CC) {
default:
llvm_unreachable("Invalid CB condition code");
case AArch64CC::EQ:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ EQ, /* Reg-Reg */ EQ);
break;
case AArch64CC::NE:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ NE, /* Reg-Reg */ NE);
break;
case AArch64CC::HS:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ HI, /* Reg-Reg */ HS);
NeedsImmDec = IsImm;
break;
case AArch64CC::LO:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ LO, /* Reg-Reg */ HI);
NeedsRegSwap = !IsImm;
break;
case AArch64CC::HI:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ HI, /* Reg-Reg */ HI);
break;
case AArch64CC::LS:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ LO, /* Reg-Reg */ HS);
NeedsRegSwap = !IsImm;
NeedsImmInc = IsImm;
break;
case AArch64CC::GE:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ GT, /* Reg-Reg */ GE);
NeedsImmDec = IsImm;
break;
case AArch64CC::LT:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ LT, /* Reg-Reg */ GT);
NeedsRegSwap = !IsImm;
break;
case AArch64CC::GT:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ GT, /* Reg-Reg */ GT);
break;
case AArch64CC::LE:
MCOpC = GET_CB_OPC(IsImm, Width, /* Reg-Imm */ LT, /* Reg-Reg */ GE);
NeedsRegSwap = !IsImm;
NeedsImmInc = IsImm;
break;
}
#undef GET_CB_OPC
MCInst Inst;
Inst.setOpcode(MCOpC);
MCOperand Lhs, Rhs, Trgt;
lowerOperand(MI->getOperand(1), Lhs);
lowerOperand(MI->getOperand(2), Rhs);
lowerOperand(MI->getOperand(3), Trgt);
// Now swap, increment or decrement
if (NeedsRegSwap) {
assert(Lhs.isReg() && "Expected register operand for CB");
assert(Rhs.isReg() && "Expected register operand for CB");
Inst.addOperand(Rhs);
Inst.addOperand(Lhs);
} else if (NeedsImmDec) {
Rhs.setImm(Rhs.getImm() - 1);
Inst.addOperand(Lhs);
Inst.addOperand(Rhs);
} else if (NeedsImmInc) {
Rhs.setImm(Rhs.getImm() + 1);
Inst.addOperand(Lhs);
Inst.addOperand(Rhs);
} else {
Inst.addOperand(Lhs);
Inst.addOperand(Rhs);
}
assert((!IsImm || (Rhs.getImm() >= 0 && Rhs.getImm() < 64)) &&
"CB immediate operand out-of-bounds");
Inst.addOperand(Trgt);
EmitToStreamer(*OutStreamer, Inst);
}
// Simple pseudo-instructions have their lowering (with expansion to real
// instructions) auto-generated.
#include "AArch64GenMCPseudoLowering.inc"
void AArch64AsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {
S.emitInstruction(Inst, *STI);
#ifndef NDEBUG
++InstsEmitted;
#endif
}
void AArch64AsmPrinter::emitInstruction(const MachineInstr *MI) {
AArch64_MC::verifyInstructionPredicates(MI->getOpcode(), STI->getFeatureBits());
#ifndef NDEBUG
InstsEmitted = 0;
llvm::scope_exit CheckMISize([&]() {
assert(STI->getInstrInfo()->getInstSizeInBytes(*MI) >= InstsEmitted * 4);
});
#endif
// Do any auto-generated pseudo lowerings.
if (MCInst OutInst; lowerPseudoInstExpansion(MI, OutInst)) {
EmitToStreamer(*OutStreamer, OutInst);
return;
}
if (MI->getOpcode() == AArch64::ADRP) {
for (auto &Opd : MI->operands()) {
if (Opd.isSymbol() && StringRef(Opd.getSymbolName()) ==
"swift_async_extendedFramePointerFlags") {
ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags = true;
}
}
}
if (AArch64FI->getLOHRelated().count(MI)) {
// Generate a label for LOH related instruction
MCSymbol *LOHLabel = createTempSymbol("loh");
// Associate the instruction with the label
LOHInstToLabel[MI] = LOHLabel;
OutStreamer->emitLabel(LOHLabel);
}
AArch64TargetStreamer *TS =
static_cast<AArch64TargetStreamer *>(OutStreamer->getTargetStreamer());
// Do any manual lowerings.
switch (MI->getOpcode()) {
default:
assert(!AArch64InstrInfo::isTailCallReturnInst(*MI) &&
"Unhandled tail call instruction");
break;
case AArch64::HINT: {
// CurrentPatchableFunctionEntrySym can be CurrentFnBegin only for
// -fpatchable-function-entry=N,0. The entry MBB is guaranteed to be
// non-empty. If MI is the initial BTI, place the
// __patchable_function_entries label after BTI.
if (CurrentPatchableFunctionEntrySym &&
CurrentPatchableFunctionEntrySym == CurrentFnBegin &&
MI == &MF->front().front()) {
int64_t Imm = MI->getOperand(0).getImm();
if ((Imm & 32) && (Imm & 6)) {
MCInst Inst;
MCInstLowering.Lower(MI, Inst);
EmitToStreamer(*OutStreamer, Inst);
CurrentPatchableFunctionEntrySym = createTempSymbol("patch");
OutStreamer->emitLabel(CurrentPatchableFunctionEntrySym);
return;
}
}
break;
}
case AArch64::MOVMCSym: {
Register DestReg = MI->getOperand(0).getReg();
const MachineOperand &MO_Sym = MI->getOperand(1);
MachineOperand Hi_MOSym(MO_Sym), Lo_MOSym(MO_Sym);
MCOperand Hi_MCSym, Lo_MCSym;
Hi_MOSym.setTargetFlags(AArch64II::MO_G1 | AArch64II::MO_S);
Lo_MOSym.setTargetFlags(AArch64II::MO_G0 | AArch64II::MO_NC);
MCInstLowering.lowerOperand(Hi_MOSym, Hi_MCSym);
MCInstLowering.lowerOperand(Lo_MOSym, Lo_MCSym);
MCInst MovZ;
MovZ.setOpcode(AArch64::MOVZXi);
MovZ.addOperand(MCOperand::createReg(DestReg));
MovZ.addOperand(Hi_MCSym);
MovZ.addOperand(MCOperand::createImm(16));
EmitToStreamer(*OutStreamer, MovZ);
MCInst MovK;
MovK.setOpcode(AArch64::MOVKXi);
MovK.addOperand(MCOperand::createReg(DestReg));
MovK.addOperand(MCOperand::createReg(DestReg));
MovK.addOperand(Lo_MCSym);
MovK.addOperand(MCOperand::createImm(0));
EmitToStreamer(*OutStreamer, MovK);
return;
}
case AArch64::MOVIv2d_ns:
// It is generally beneficial to rewrite "fmov s0, wzr" to "movi d0, #0".
// as movi is more efficient across all cores. Newer cores can eliminate
// fmovs early and there is no difference with movi, but this not true for
// all implementations.
//
// The floating-point version doesn't quite work in rare cases on older
// CPUs, so on those targets we lower this instruction to movi.16b instead.
if (STI->hasZeroCycleZeroingFPWorkaround() &&
MI->getOperand(1).getImm() == 0) {
MCInst TmpInst;
TmpInst.setOpcode(AArch64::MOVIv16b_ns);
TmpInst.addOperand(MCOperand::createReg(MI->getOperand(0).getReg()));
TmpInst.addOperand(MCOperand::createImm(0));
EmitToStreamer(*OutStreamer, TmpInst);
return;
}
break;
case AArch64::DBG_VALUE:
case AArch64::DBG_VALUE_LIST:
if (isVerbose() && OutStreamer->hasRawTextSupport()) {
SmallString<128> TmpStr;
raw_svector_ostream OS(TmpStr);
PrintDebugValueComment(MI, OS);
OutStreamer->emitRawText(StringRef(OS.str()));
}
return;
case AArch64::EMITBKEY: {
ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
ExceptionHandlingType != ExceptionHandling::ARM)
return;
if (getFunctionCFISectionType(*MF) == CFISection::None)
return;
OutStreamer->emitCFIBKeyFrame();
return;
}
case AArch64::EMITMTETAGGED: {
ExceptionHandling ExceptionHandlingType = MAI->getExceptionHandlingType();
if (ExceptionHandlingType != ExceptionHandling::DwarfCFI &&
ExceptionHandlingType != ExceptionHandling::ARM)
return;
if (getFunctionCFISectionType(*MF) != CFISection::None)
OutStreamer->emitCFIMTETaggedFrame();
return;
}
case AArch64::AUTx16x17: {
const Register Pointer = AArch64::X16;
const Register Scratch = AArch64::X17;
PtrAuthSchema AuthSchema((AArch64PACKey::ID)MI->getOperand(0).getImm(),
MI->getOperand(1).getImm(), MI->getOperand(2));
emitPtrauthAuthResign(Pointer, Scratch, AuthSchema, std::nullopt,
std::nullopt, MI->getDeactivationSymbol());
return;
}
case AArch64::AUTxMxN: {
const Register Pointer = MI->getOperand(0).getReg();
const Register Scratch = MI->getOperand(1).getReg();
PtrAuthSchema AuthSchema((AArch64PACKey::ID)MI->getOperand(3).getImm(),
MI->getOperand(4).getImm(), MI->getOperand(5));
emitPtrauthAuthResign(Pointer, Scratch, AuthSchema, std::nullopt,
std::nullopt, MI->getDeactivationSymbol());
return;
}
case AArch64::AUTPAC: {
const Register Pointer = AArch64::X16;
const Register Scratch = AArch64::X17;
PtrAuthSchema AuthSchema((AArch64PACKey::ID)MI->getOperand(0).getImm(),
MI->getOperand(1).getImm(), MI->getOperand(2));
PtrAuthSchema SignSchema((AArch64PACKey::ID)MI->getOperand(3).getImm(),
MI->getOperand(4).getImm(), MI->getOperand(5));
emitPtrauthAuthResign(Pointer, Scratch, AuthSchema, SignSchema,
std::nullopt, MI->getDeactivationSymbol());
return;
}
case AArch64::AUTRELLOADPAC: {
const Register Pointer = AArch64::X16;
const Register Scratch = AArch64::X17;
PtrAuthSchema AuthSchema((AArch64PACKey::ID)MI->getOperand(0).getImm(),
MI->getOperand(1).getImm(), MI->getOperand(2));
PtrAuthSchema SignSchema((AArch64PACKey::ID)MI->getOperand(3).getImm(),
MI->getOperand(4).getImm(), MI->getOperand(5));
emitPtrauthAuthResign(Pointer, Scratch, AuthSchema, SignSchema,
MI->getOperand(6).getImm(),
MI->getDeactivationSymbol());
return;
}
case AArch64::PAC:
emitPtrauthSign(MI);
return;
case AArch64::LOADauthptrstatic:
LowerLOADauthptrstatic(*MI);
return;
case AArch64::LOADgotPAC:
case AArch64::MOVaddrPAC:
LowerMOVaddrPAC(*MI);
return;
case AArch64::LOADgotAUTH:
LowerLOADgotAUTH(*MI);
return;
case AArch64::BRA:
case AArch64::BLRA:
emitPtrauthBranch(MI);
return;
// Tail calls use pseudo instructions so they have the proper code-gen
// attributes (isCall, isReturn, etc.). We lower them to the real
// instruction here.
case AArch64::AUTH_TCRETURN:
case AArch64::AUTH_TCRETURN_BTI: {
Register Callee = MI->getOperand(0).getReg();
const auto Key = (AArch64PACKey::ID)MI->getOperand(2).getImm();
const uint64_t Disc = MI->getOperand(3).getImm();
Register AddrDisc = MI->getOperand(4).getReg();
Register ScratchReg = Callee == AArch64::X16 ? AArch64::X17 : AArch64::X16;
emitPtrauthTailCallHardening(MI);
// See the comments in emitPtrauthBranch.
if (Callee == AddrDisc)
report_fatal_error("Call target is signed with its own value");
// After isX16X17Safer predicate was introduced, emitPtrauthDiscriminator is
// no longer restricted to only reusing AddrDisc when it is X16 or X17
// (which are implicit-def'ed by AUTH_TCRETURN pseudos), thus impose this
// restriction manually not to clobber an unexpected register.
bool AddrDiscIsImplicitDef =
AddrDisc == AArch64::X16 || AddrDisc == AArch64::X17;
Register DiscReg = emitPtrauthDiscriminator(Disc, AddrDisc, ScratchReg,
AddrDiscIsImplicitDef);
emitBLRA(/*IsCall*/ false, Key, Callee, DiscReg);
return;
}
case AArch64::TCRETURNri:
case AArch64::TCRETURNrix16x17:
case AArch64::TCRETURNrix17:
case AArch64::TCRETURNrinotx16:
case AArch64::TCRETURNriALL: {
emitPtrauthTailCallHardening(MI);
recordIfImportCall(MI);
MCInst TmpInst;
TmpInst.setOpcode(AArch64::BR);
TmpInst.addOperand(MCOperand::createReg(MI->getOperand(0).getReg()));
EmitToStreamer(*OutStreamer, TmpInst);
return;
}
case AArch64::TCRETURNdi: {
emitPtrauthTailCallHardening(MI);
MCOperand Dest;
MCInstLowering.lowerOperand(MI->getOperand(0), Dest);
recordIfImportCall(MI);
MCInst TmpInst;
TmpInst.setOpcode(AArch64::B);
TmpInst.addOperand(Dest);
EmitToStreamer(*OutStreamer, TmpInst);
return;
}
case AArch64::SpeculationBarrierISBDSBEndBB: {
// Print DSB SYS + ISB
MCInst TmpInstDSB;
TmpInstDSB.setOpcode(AArch64::DSB);
TmpInstDSB.addOperand(MCOperand::createImm(0xf));
EmitToStreamer(*OutStreamer, TmpInstDSB);
MCInst TmpInstISB;
TmpInstISB.setOpcode(AArch64::ISB);
TmpInstISB.addOperand(MCOperand::createImm(0xf));
EmitToStreamer(*OutStreamer, TmpInstISB);
return;
}
case AArch64::SpeculationBarrierSBEndBB: {
// Print SB
MCInst TmpInstSB;
TmpInstSB.setOpcode(AArch64::SB);
EmitToStreamer(*OutStreamer, TmpInstSB);
return;
}
case AArch64::TLSDESC_AUTH_CALLSEQ: {
/// lower this to:
/// adrp x0, :tlsdesc_auth:var
/// ldr x16, [x0, #:tlsdesc_auth_lo12:var]
/// add x0, x0, #:tlsdesc_auth_lo12:var
/// blraa x16, x0
/// (TPIDR_EL0 offset now in x0)
const MachineOperand &MO_Sym = MI->getOperand(0);
MachineOperand MO_TLSDESC_LO12(MO_Sym), MO_TLSDESC(MO_Sym);
MCOperand SymTLSDescLo12, SymTLSDesc;
MO_TLSDESC_LO12.setTargetFlags(AArch64II::MO_TLS | AArch64II::MO_PAGEOFF);
MO_TLSDESC.setTargetFlags(AArch64II::MO_TLS | AArch64II::MO_PAGE);
MCInstLowering.lowerOperand(MO_TLSDESC_LO12, SymTLSDescLo12);
MCInstLowering.lowerOperand(MO_TLSDESC, SymTLSDesc);
MCInst Adrp;
Adrp.setOpcode(AArch64::ADRP);
Adrp.addOperand(MCOperand::createReg(AArch64::X0));
Adrp.addOperand(SymTLSDesc);
EmitToStreamer(*OutStreamer, Adrp);
MCInst Ldr;
Ldr.setOpcode(AArch64::LDRXui);
Ldr.addOperand(MCOperand::createReg(AArch64::X16));
Ldr.addOperand(MCOperand::createReg(AArch64::X0));
Ldr.addOperand(SymTLSDescLo12);
Ldr.addOperand(MCOperand::createImm(0));
EmitToStreamer(*OutStreamer, Ldr);
MCInst Add;
Add.setOpcode(AArch64::ADDXri);
Add.addOperand(MCOperand::createReg(AArch64::X0));
Add.addOperand(MCOperand::createReg(AArch64::X0));
Add.addOperand(SymTLSDescLo12);
Add.addOperand(MCOperand::createImm(AArch64_AM::getShiftValue(0)));
EmitToStreamer(*OutStreamer, Add);
// Authenticated TLSDESC accesses are not relaxed.
// Thus, do not emit .tlsdesccall for AUTH TLSDESC.
MCInst Blraa;
Blraa.setOpcode(AArch64::BLRAA);
Blraa.addOperand(MCOperand::createReg(AArch64::X16));
Blraa.addOperand(MCOperand::createReg(AArch64::X0));
EmitToStreamer(*OutStreamer, Blraa);
return;
}
case AArch64::TLSDESC_CALLSEQ: {
/// lower this to:
/// adrp x0, :tlsdesc:var
/// ldr x1, [x0, #:tlsdesc_lo12:var]
/// add x0, x0, #:tlsdesc_lo12:var
/// .tlsdesccall var
/// blr x1
/// (TPIDR_EL0 offset now in x0)
const MachineOperand &MO_Sym = MI->getOperand(0);
MachineOperand MO_TLSDESC_LO12(MO_Sym), MO_TLSDESC(MO_Sym);
MCOperand Sym, SymTLSDescLo12, SymTLSDesc;
MO_TLSDESC_LO12.setTargetFlags(AArch64II::MO_TLS | AArch64II::MO_PAGEOFF);
MO_TLSDESC.setTargetFlags(AArch64II::MO_TLS | AArch64II::MO_PAGE);
MCInstLowering.lowerOperand(MO_Sym, Sym);
MCInstLowering.lowerOperand(MO_TLSDESC_LO12, SymTLSDescLo12);
MCInstLowering.lowerOperand(MO_TLSDESC, SymTLSDesc);
MCInst Adrp;
Adrp.setOpcode(AArch64::ADRP);
Adrp.addOperand(MCOperand::createReg(AArch64::X0));
Adrp.addOperand(SymTLSDesc);
EmitToStreamer(*OutStreamer, Adrp);
MCInst Ldr;
if (STI->isTargetILP32()) {
Ldr.setOpcode(AArch64::LDRWui);
Ldr.addOperand(MCOperand::createReg(AArch64::W1));
} else {
Ldr.setOpcode(AArch64::LDRXui);
Ldr.addOperand(MCOperand::createReg(AArch64::X1));
}
Ldr.addOperand(MCOperand::createReg(AArch64::X0));
Ldr.addOperand(SymTLSDescLo12);
Ldr.addOperand(MCOperand::createImm(0));
EmitToStreamer(*OutStreamer, Ldr);
MCInst Add;
if (STI->isTargetILP32()) {
Add.setOpcode(AArch64::ADDWri);
Add.addOperand(MCOperand::createReg(AArch64::W0));
Add.addOperand(MCOperand::createReg(AArch64::W0));
} else {
Add.setOpcode(AArch64::ADDXri);
Add.addOperand(MCOperand::createReg(AArch64::X0));
Add.addOperand(MCOperand::createReg(AArch64::X0));
}
Add.addOperand(SymTLSDescLo12);
Add.addOperand(MCOperand::createImm(AArch64_AM::getShiftValue(0)));
EmitToStreamer(*OutStreamer, Add);
// Emit a relocation-annotation. This expands to no code, but requests
// the following instruction gets an R_AARCH64_TLSDESC_CALL.
MCInst TLSDescCall;
TLSDescCall.setOpcode(AArch64::TLSDESCCALL);
TLSDescCall.addOperand(Sym);
EmitToStreamer(*OutStreamer, TLSDescCall);
#ifndef NDEBUG
--InstsEmitted; // no code emitted
#endif
MCInst Blr;
Blr.setOpcode(AArch64::BLR);
Blr.addOperand(MCOperand::createReg(AArch64::X1));
EmitToStreamer(*OutStreamer, Blr);
return;
}
case AArch64::JumpTableDest32:
case AArch64::JumpTableDest16:
case AArch64::JumpTableDest8:
LowerJumpTableDest(*OutStreamer, *MI);
return;
case AArch64::BR_JumpTable:
LowerHardenedBRJumpTable(*MI);
return;
case AArch64::FMOVH0:
case AArch64::FMOVS0:
case AArch64::FMOVD0:
emitFMov0(*MI);
return;
case AArch64::MOPSMemoryCopyPseudo:
case AArch64::MOPSMemoryMovePseudo:
case AArch64::MOPSMemorySetPseudo:
case AArch64::MOPSMemorySetTaggingPseudo:
LowerMOPS(*OutStreamer, *MI);
return;
case TargetOpcode::STACKMAP:
return LowerSTACKMAP(*OutStreamer, SM, *MI);
case TargetOpcode::PATCHPOINT:
return LowerPATCHPOINT(*OutStreamer, SM, *MI);
case TargetOpcode::STATEPOINT:
return LowerSTATEPOINT(*OutStreamer, SM, *MI);
case TargetOpcode::FAULTING_OP:
return LowerFAULTING_OP(*MI);
case TargetOpcode::PATCHABLE_FUNCTION_ENTER:
LowerPATCHABLE_FUNCTION_ENTER(*MI);
return;
case TargetOpcode::PATCHABLE_FUNCTION_EXIT:
LowerPATCHABLE_FUNCTION_EXIT(*MI);
return;
case TargetOpcode::PATCHABLE_TAIL_CALL:
LowerPATCHABLE_TAIL_CALL(*MI);
return;
case TargetOpcode::PATCHABLE_EVENT_CALL:
return LowerPATCHABLE_EVENT_CALL(*MI, false);
case TargetOpcode::PATCHABLE_TYPED_EVENT_CALL:
return LowerPATCHABLE_EVENT_CALL(*MI, true);
case AArch64::KCFI_CHECK:
LowerKCFI_CHECK(*MI);
return;
case AArch64::HWASAN_CHECK_MEMACCESS:
case AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES:
case AArch64::HWASAN_CHECK_MEMACCESS_FIXEDSHADOW:
case AArch64::HWASAN_CHECK_MEMACCESS_SHORTGRANULES_FIXEDSHADOW:
LowerHWASAN_CHECK_MEMACCESS(*MI);
return;
case AArch64::SEH_StackAlloc:
TS->emitARM64WinCFIAllocStack(MI->getOperand(0).getImm());
return;
case AArch64::SEH_SaveFPLR:
TS->emitARM64WinCFISaveFPLR(MI->getOperand(0).getImm());
return;
case AArch64::SEH_SaveFPLR_X:
assert(MI->getOperand(0).getImm() < 0 &&
"Pre increment SEH opcode must have a negative offset");
TS->emitARM64WinCFISaveFPLRX(-MI->getOperand(0).getImm());
return;
case AArch64::SEH_SaveReg:
TS->emitARM64WinCFISaveReg(MI->getOperand(0).getImm(),
MI->getOperand(1).getImm());
return;
case AArch64::SEH_SaveReg_X:
assert(MI->getOperand(1).getImm() < 0 &&
"Pre increment SEH opcode must have a negative offset");
TS->emitARM64WinCFISaveRegX(MI->getOperand(0).getImm(),
-MI->getOperand(1).getImm());
return;
case AArch64::SEH_SaveRegP:
if (MI->getOperand(1).getImm() == 30 && MI->getOperand(0).getImm() >= 19 &&
MI->getOperand(0).getImm() <= 28) {
assert((MI->getOperand(0).getImm() - 19) % 2 == 0 &&
"Register paired with LR must be odd");
TS->emitARM64WinCFISaveLRPair(MI->getOperand(0).getImm(),
MI->getOperand(2).getImm());
return;
}
assert((MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1) &&
"Non-consecutive registers not allowed for save_regp");
TS->emitARM64WinCFISaveRegP(MI->getOperand(0).getImm(),
MI->getOperand(2).getImm());
return;
case AArch64::SEH_SaveRegP_X:
assert((MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1) &&
"Non-consecutive registers not allowed for save_regp_x");
assert(MI->getOperand(2).getImm() < 0 &&
"Pre increment SEH opcode must have a negative offset");
TS->emitARM64WinCFISaveRegPX(MI->getOperand(0).getImm(),
-MI->getOperand(2).getImm());
return;
case AArch64::SEH_SaveFReg:
TS->emitARM64WinCFISaveFReg(MI->getOperand(0).getImm(),
MI->getOperand(1).getImm());
return;
case AArch64::SEH_SaveFReg_X:
assert(MI->getOperand(1).getImm() < 0 &&
"Pre increment SEH opcode must have a negative offset");
TS->emitARM64WinCFISaveFRegX(MI->getOperand(0).getImm(),
-MI->getOperand(1).getImm());
return;
case AArch64::SEH_SaveFRegP:
assert((MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1) &&
"Non-consecutive registers not allowed for save_regp");
TS->emitARM64WinCFISaveFRegP(MI->getOperand(0).getImm(),
MI->getOperand(2).getImm());
return;
case AArch64::SEH_SaveFRegP_X:
assert((MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1) &&
"Non-consecutive registers not allowed for save_regp_x");
assert(MI->getOperand(2).getImm() < 0 &&
"Pre increment SEH opcode must have a negative offset");
TS->emitARM64WinCFISaveFRegPX(MI->getOperand(0).getImm(),
-MI->getOperand(2).getImm());
return;
case AArch64::SEH_SetFP:
TS->emitARM64WinCFISetFP();
return;
case AArch64::SEH_AddFP:
TS->emitARM64WinCFIAddFP(MI->getOperand(0).getImm());
return;
case AArch64::SEH_Nop:
TS->emitARM64WinCFINop();
return;
case AArch64::SEH_PrologEnd:
TS->emitARM64WinCFIPrologEnd();
return;
case AArch64::SEH_EpilogStart:
TS->emitARM64WinCFIEpilogStart();
return;
case AArch64::SEH_EpilogEnd:
TS->emitARM64WinCFIEpilogEnd();
return;
case AArch64::SEH_PACSignLR:
TS->emitARM64WinCFIPACSignLR();
return;
case AArch64::SEH_SaveAnyRegI:
assert(MI->getOperand(1).getImm() <= 1008 &&
"SaveAnyRegQP SEH opcode offset must fit into 6 bits");
TS->emitARM64WinCFISaveAnyRegI(MI->getOperand(0).getImm(),
MI->getOperand(1).getImm());
return;
case AArch64::SEH_SaveAnyRegIP:
assert(MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1 &&
"Non-consecutive registers not allowed for save_any_reg");
assert(MI->getOperand(2).getImm() <= 1008 &&
"SaveAnyRegQP SEH opcode offset must fit into 6 bits");
TS->emitARM64WinCFISaveAnyRegIP(MI->getOperand(0).getImm(),
MI->getOperand(2).getImm());
return;
case AArch64::SEH_SaveAnyRegQP:
assert(MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1 &&
"Non-consecutive registers not allowed for save_any_reg");
assert(MI->getOperand(2).getImm() >= 0 &&
"SaveAnyRegQP SEH opcode offset must be non-negative");
assert(MI->getOperand(2).getImm() <= 1008 &&
"SaveAnyRegQP SEH opcode offset must fit into 6 bits");
TS->emitARM64WinCFISaveAnyRegQP(MI->getOperand(0).getImm(),
MI->getOperand(2).getImm());
return;
case AArch64::SEH_SaveAnyRegQPX:
assert(MI->getOperand(1).getImm() - MI->getOperand(0).getImm() == 1 &&
"Non-consecutive registers not allowed for save_any_reg");
assert(MI->getOperand(2).getImm() < 0 &&
"SaveAnyRegQPX SEH opcode offset must be negative");
assert(MI->getOperand(2).getImm() >= -1008 &&
"SaveAnyRegQPX SEH opcode offset must fit into 6 bits");
TS->emitARM64WinCFISaveAnyRegQPX(MI->getOperand(0).getImm(),
-MI->getOperand(2).getImm());
return;
case AArch64::SEH_AllocZ:
assert(MI->getOperand(0).getImm() >= 0 &&
"AllocZ SEH opcode offset must be non-negative");
assert(MI->getOperand(0).getImm() <= 255 &&
"AllocZ SEH opcode offset must fit into 8 bits");
TS->emitARM64WinCFIAllocZ(MI->getOperand(0).getImm());
return;
case AArch64::SEH_SaveZReg:
assert(MI->getOperand(1).getImm() >= 0 &&
"SaveZReg SEH opcode offset must be non-negative");
assert(MI->getOperand(1).getImm() <= 255 &&
"SaveZReg SEH opcode offset must fit into 8 bits");
TS->emitARM64WinCFISaveZReg(MI->getOperand(0).getImm(),
MI->getOperand(1).getImm());
return;
case AArch64::SEH_SavePReg:
assert(MI->getOperand(1).getImm() >= 0 &&
"SavePReg SEH opcode offset must be non-negative");
assert(MI->getOperand(1).getImm() <= 255 &&
"SavePReg SEH opcode offset must fit into 8 bits");
TS->emitARM64WinCFISavePReg(MI->getOperand(0).getImm(),
MI->getOperand(1).getImm());
return;
case AArch64::BLR:
case AArch64::BR: {
recordIfImportCall(MI);
MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
EmitToStreamer(*OutStreamer, TmpInst);
return;
}
case AArch64::CBWPri:
case AArch64::CBXPri:
case AArch64::CBBAssertExt:
case AArch64::CBHAssertExt:
case AArch64::CBWPrr:
case AArch64::CBXPrr:
emitCBPseudoExpansion(MI);
return;
}
if (emitDeactivationSymbolRelocation(MI->getDeactivationSymbol()))
return;
// Finally, do the automated lowerings for everything else.
MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
EmitToStreamer(*OutStreamer, TmpInst);
}
void AArch64AsmPrinter::recordIfImportCall(
const llvm::MachineInstr *BranchInst) {
if (!EnableImportCallOptimization)
return;
auto [GV, OpFlags] = BranchInst->getMF()->tryGetCalledGlobal(BranchInst);
if (GV && GV->hasDLLImportStorageClass()) {
auto *CallSiteSymbol = MMI->getContext().createNamedTempSymbol("impcall");
OutStreamer->emitLabel(CallSiteSymbol);
auto *CalledSymbol = MCInstLowering.GetGlobalValueSymbol(GV, OpFlags);
SectionToImportedFunctionCalls[OutStreamer->getCurrentSectionOnly()]
.push_back({CallSiteSymbol, CalledSymbol});
}
}
void AArch64AsmPrinter::emitMachOIFuncStubBody(Module &M, const GlobalIFunc &GI,
MCSymbol *LazyPointer) {
// _ifunc:
// adrp x16, lazy_pointer@GOTPAGE
// ldr x16, [x16, lazy_pointer@GOTPAGEOFF]
// ldr x16, [x16]
// br x16
{
MCInst Adrp;
Adrp.setOpcode(AArch64::ADRP);
Adrp.addOperand(MCOperand::createReg(AArch64::X16));
MCOperand SymPage;
MCInstLowering.lowerOperand(
MachineOperand::CreateMCSymbol(LazyPointer,
AArch64II::MO_GOT | AArch64II::MO_PAGE),
SymPage);
Adrp.addOperand(SymPage);
EmitToStreamer(Adrp);
}
{
MCInst Ldr;
Ldr.setOpcode(AArch64::LDRXui);
Ldr.addOperand(MCOperand::createReg(AArch64::X16));
Ldr.addOperand(MCOperand::createReg(AArch64::X16));
MCOperand SymPageOff;
MCInstLowering.lowerOperand(
MachineOperand::CreateMCSymbol(LazyPointer, AArch64II::MO_GOT |
AArch64II::MO_PAGEOFF),
SymPageOff);
Ldr.addOperand(SymPageOff);
Ldr.addOperand(MCOperand::createImm(0));
EmitToStreamer(Ldr);
}
EmitToStreamer(MCInstBuilder(AArch64::LDRXui)
.addReg(AArch64::X16)
.addReg(AArch64::X16)
.addImm(0));
EmitToStreamer(MCInstBuilder(TM.getTargetTriple().isArm64e() ? AArch64::BRAAZ
: AArch64::BR)
.addReg(AArch64::X16));
}
void AArch64AsmPrinter::emitMachOIFuncStubHelperBody(Module &M,
const GlobalIFunc &GI,
MCSymbol *LazyPointer) {
// These stub helpers are only ever called once, so here we're optimizing for
// minimum size by using the pre-indexed store variants, which saves a few
// bytes of instructions to bump & restore sp.
// _ifunc.stub_helper:
// stp fp, lr, [sp, #-16]!
// mov fp, sp
// stp x1, x0, [sp, #-16]!
// stp x3, x2, [sp, #-16]!
// stp x5, x4, [sp, #-16]!
// stp x7, x6, [sp, #-16]!
// stp d1, d0, [sp, #-16]!
// stp d3, d2, [sp, #-16]!
// stp d5, d4, [sp, #-16]!
// stp d7, d6, [sp, #-16]!
// bl _resolver
// adrp x16, lazy_pointer@GOTPAGE
// ldr x16, [x16, lazy_pointer@GOTPAGEOFF]
// str x0, [x16]
// mov x16, x0
// ldp d7, d6, [sp], #16
// ldp d5, d4, [sp], #16
// ldp d3, d2, [sp], #16
// ldp d1, d0, [sp], #16
// ldp x7, x6, [sp], #16
// ldp x5, x4, [sp], #16
// ldp x3, x2, [sp], #16
// ldp x1, x0, [sp], #16
// ldp fp, lr, [sp], #16
// br x16
EmitToStreamer(MCInstBuilder(AArch64::STPXpre)
.addReg(AArch64::SP)
.addReg(AArch64::FP)
.addReg(AArch64::LR)
.addReg(AArch64::SP)
.addImm(-2));
EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
.addReg(AArch64::FP)
.addReg(AArch64::SP)
.addImm(0)
.addImm(0));
for (int I = 0; I != 4; ++I)
EmitToStreamer(MCInstBuilder(AArch64::STPXpre)
.addReg(AArch64::SP)
.addReg(AArch64::X1 + 2 * I)
.addReg(AArch64::X0 + 2 * I)
.addReg(AArch64::SP)
.addImm(-2));
for (int I = 0; I != 4; ++I)
EmitToStreamer(MCInstBuilder(AArch64::STPDpre)
.addReg(AArch64::SP)
.addReg(AArch64::D1 + 2 * I)
.addReg(AArch64::D0 + 2 * I)
.addReg(AArch64::SP)
.addImm(-2));
EmitToStreamer(
MCInstBuilder(AArch64::BL)
.addOperand(MCOperand::createExpr(lowerConstant(GI.getResolver()))));
{
MCInst Adrp;
Adrp.setOpcode(AArch64::ADRP);
Adrp.addOperand(MCOperand::createReg(AArch64::X16));
MCOperand SymPage;
MCInstLowering.lowerOperand(
MachineOperand::CreateES(LazyPointer->getName().data() + 1,
AArch64II::MO_GOT | AArch64II::MO_PAGE),
SymPage);
Adrp.addOperand(SymPage);
EmitToStreamer(Adrp);
}
{
MCInst Ldr;
Ldr.setOpcode(AArch64::LDRXui);
Ldr.addOperand(MCOperand::createReg(AArch64::X16));
Ldr.addOperand(MCOperand::createReg(AArch64::X16));
MCOperand SymPageOff;
MCInstLowering.lowerOperand(
MachineOperand::CreateES(LazyPointer->getName().data() + 1,
AArch64II::MO_GOT | AArch64II::MO_PAGEOFF),
SymPageOff);
Ldr.addOperand(SymPageOff);
Ldr.addOperand(MCOperand::createImm(0));
EmitToStreamer(Ldr);
}
EmitToStreamer(MCInstBuilder(AArch64::STRXui)
.addReg(AArch64::X0)
.addReg(AArch64::X16)
.addImm(0));
EmitToStreamer(MCInstBuilder(AArch64::ADDXri)
.addReg(AArch64::X16)
.addReg(AArch64::X0)
.addImm(0)
.addImm(0));
for (int I = 3; I != -1; --I)
EmitToStreamer(MCInstBuilder(AArch64::LDPDpost)
.addReg(AArch64::SP)
.addReg(AArch64::D1 + 2 * I)
.addReg(AArch64::D0 + 2 * I)
.addReg(AArch64::SP)
.addImm(2));
for (int I = 3; I != -1; --I)
EmitToStreamer(MCInstBuilder(AArch64::LDPXpost)
.addReg(AArch64::SP)
.addReg(AArch64::X1 + 2 * I)
.addReg(AArch64::X0 + 2 * I)
.addReg(AArch64::SP)
.addImm(2));
EmitToStreamer(MCInstBuilder(AArch64::LDPXpost)
.addReg(AArch64::SP)
.addReg(AArch64::FP)
.addReg(AArch64::LR)
.addReg(AArch64::SP)
.addImm(2));
EmitToStreamer(MCInstBuilder(TM.getTargetTriple().isArm64e() ? AArch64::BRAAZ
: AArch64::BR)
.addReg(AArch64::X16));
}
const MCExpr *AArch64AsmPrinter::lowerConstant(const Constant *CV,
const Constant *BaseCV,
uint64_t Offset) {
if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV)) {
return MCSymbolRefExpr::create(MCInstLowering.GetGlobalValueSymbol(GV, 0),
OutContext);
}
return AsmPrinter::lowerConstant(CV, BaseCV, Offset);
}
char AArch64AsmPrinter::ID = 0;
INITIALIZE_PASS(AArch64AsmPrinter, "aarch64-asm-printer",
"AArch64 Assembly Printer", false, false)
// Force static initialization.
extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
LLVMInitializeAArch64AsmPrinter() {
RegisterAsmPrinter<AArch64AsmPrinter> X(getTheAArch64leTarget());
RegisterAsmPrinter<AArch64AsmPrinter> Y(getTheAArch64beTarget());
RegisterAsmPrinter<AArch64AsmPrinter> Z(getTheARM64Target());
RegisterAsmPrinter<AArch64AsmPrinter> W(getTheARM64_32Target());
RegisterAsmPrinter<AArch64AsmPrinter> V(getTheAArch64_32Target());
}
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