Google Git Google Git
Sign in
llvm/llvm-project/6b26457a0ef2994de54606eb5c356cb897cadda2/./llvm/lib/Target/ARM/ARMAsmPrinter.cpp
blob: ef21aa3ba6adfb776cf6c417768a3e766d6aae32 [file]
//===-- ARMAsmPrinter.cpp - Print machine code to an ARM .s file ----------===//
//
// 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 GAS-format ARM assembly language.
//
//===----------------------------------------------------------------------===//
#include "ARMAsmPrinter.h"
#include "ARM.h"
#include "ARMConstantPoolValue.h"
#include "ARMMachineFunctionInfo.h"
#include "ARMTargetMachine.h"
#include "ARMTargetObjectFile.h"
#include "MCTargetDesc/ARMInstPrinter.h"
#include "MCTargetDesc/ARMMCAsmInfo.h"
#include "TargetInfo/ARMTargetInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/CodeGen/MachineJumpTableInfo.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCELFStreamer.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstBuilder.h"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/ARMBuildAttributes.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
#define DEBUG_TYPE "asm-printer"
ARMAsmPrinter::ARMAsmPrinter(TargetMachine &TM,
std::unique_ptr<MCStreamer> Streamer)
: AsmPrinter(TM, std::move(Streamer), ID), AFI(nullptr), MCP(nullptr),
InConstantPool(false), OptimizationGoals(-1) {}
const ARMBaseTargetMachine &ARMAsmPrinter::getTM() const {
return static_cast<const ARMBaseTargetMachine &>(TM);
}
void ARMAsmPrinter::emitFunctionBodyEnd() {
// Make sure to terminate any constant pools that were at the end
// of the function.
if (!InConstantPool)
return;
InConstantPool = false;
OutStreamer->emitDataRegion(MCDR_DataRegionEnd);
}
void ARMAsmPrinter::emitFunctionEntryLabel() {
auto &TS =
static_cast<ARMTargetStreamer &>(*OutStreamer->getTargetStreamer());
if (AFI->isThumbFunction()) {
TS.emitCode16();
TS.emitThumbFunc(CurrentFnSym);
} else {
TS.emitCode32();
}
// Emit symbol for CMSE non-secure entry point
if (AFI->isCmseNSEntryFunction()) {
MCSymbol *S =
OutContext.getOrCreateSymbol("__acle_se_" + CurrentFnSym->getName());
emitLinkage(&MF->getFunction(), S);
OutStreamer->emitSymbolAttribute(S, MCSA_ELF_TypeFunction);
OutStreamer->emitLabel(S);
}
AsmPrinter::emitFunctionEntryLabel();
}
void ARMAsmPrinter::emitXXStructor(const DataLayout &DL, const Constant *CV) {
uint64_t Size = getDataLayout().getTypeAllocSize(CV->getType());
assert(Size && "C++ constructor pointer had zero size!");
const GlobalValue *GV = dyn_cast<GlobalValue>(CV->stripPointerCasts());
assert(GV && "C++ constructor pointer was not a GlobalValue!");
const MCExpr *E = MCSymbolRefExpr::create(
GetARMGVSymbol(GV, ARMII::MO_NO_FLAG),
(TM.getTargetTriple().isOSBinFormatELF() ? ARM::S_TARGET1 : ARM::S_None),
OutContext);
OutStreamer->emitValue(E, Size);
}
// An alias to a cmse entry function should also emit a `__acle_se_` symbol.
void ARMAsmPrinter::emitCMSEVeneerAlias(const GlobalAlias &GA) {
const Function *BaseFn = dyn_cast_or_null<Function>(GA.getAliaseeObject());
if (!BaseFn || !BaseFn->hasFnAttribute("cmse_nonsecure_entry"))
return;
MCSymbol *AliasSym = getSymbol(&GA);
MCSymbol *FnSym = getSymbol(BaseFn);
MCSymbol *SEAliasSym =
OutContext.getOrCreateSymbol(Twine("__acle_se_") + AliasSym->getName());
MCSymbol *SEBaseSym =
OutContext.getOrCreateSymbol(Twine("__acle_se_") + FnSym->getName());
// Mirror alias linkage/visibility onto the veneer-alias symbol.
emitLinkage(&GA, SEAliasSym);
OutStreamer->emitSymbolAttribute(SEAliasSym, MCSA_ELF_TypeFunction);
emitVisibility(SEAliasSym, GA.getVisibility());
// emit "__acle_se_<alias> = __acle_se_<aliasee>"
const MCExpr *SEExpr = MCSymbolRefExpr::create(SEBaseSym, OutContext);
OutStreamer->emitAssignment(SEAliasSym, SEExpr);
}
void ARMAsmPrinter::emitGlobalAlias(const Module &M, const GlobalAlias &GA) {
AsmPrinter::emitGlobalAlias(M, GA);
emitCMSEVeneerAlias(GA);
}
void ARMAsmPrinter::emitGlobalVariable(const GlobalVariable *GV) {
if (PromotedGlobals.count(GV))
// The global was promoted into a constant pool. It should not be emitted.
return;
AsmPrinter::emitGlobalVariable(GV);
}
/// runOnMachineFunction - This uses the emitInstruction()
/// method to print assembly for each instruction.
///
bool ARMAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
AFI = MF.getInfo<ARMFunctionInfo>();
MCP = MF.getConstantPool();
SetupMachineFunction(MF);
const Function &F = MF.getFunction();
const TargetMachine& TM = MF.getTarget();
// Collect all globals that had their storage promoted to a constant pool.
// Functions are emitted before variables, so this accumulates promoted
// globals from all functions in PromotedGlobals.
PromotedGlobals.insert_range(AFI->getGlobalsPromotedToConstantPool());
// Calculate this function's optimization goal.
unsigned OptimizationGoal;
if (F.hasOptNone())
// For best debugging illusion, speed and small size sacrificed
OptimizationGoal = 6;
else if (F.hasMinSize())
// Aggressively for small size, speed and debug illusion sacrificed
OptimizationGoal = 4;
else if (F.hasOptSize())
// For small size, but speed and debugging illusion preserved
OptimizationGoal = 3;
else if (TM.getOptLevel() == CodeGenOptLevel::Aggressive)
// Aggressively for speed, small size and debug illusion sacrificed
OptimizationGoal = 2;
else if (TM.getOptLevel() > CodeGenOptLevel::None)
// For speed, but small size and good debug illusion preserved
OptimizationGoal = 1;
else // TM.getOptLevel() == CodeGenOptLevel::None
// For good debugging, but speed and small size preserved
OptimizationGoal = 5;
// Combine a new optimization goal with existing ones.
if (OptimizationGoals == -1) // uninitialized goals
OptimizationGoals = OptimizationGoal;
else if (OptimizationGoals != (int)OptimizationGoal) // conflicting goals
OptimizationGoals = 0;
if (TM.getTargetTriple().isOSBinFormatCOFF()) {
bool Local = F.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();
// If we need V4T thumb mode Register Indirect Jump pads, emit them.
// These are created per function, rather than per TU, since it's
// relatively easy to exceed the thumb branch range within a TU.
if (! ThumbIndirectPads.empty()) {
auto &TS =
static_cast<ARMTargetStreamer &>(*OutStreamer->getTargetStreamer());
TS.emitCode16();
emitAlignment(Align(2));
for (std::pair<unsigned, MCSymbol *> &TIP : ThumbIndirectPads) {
OutStreamer->emitLabel(TIP.second);
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tBX)
.addReg(TIP.first)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
}
ThumbIndirectPads.clear();
}
// We didn't modify anything.
return false;
}
void ARMAsmPrinter::PrintSymbolOperand(const MachineOperand &MO,
raw_ostream &O) {
assert(MO.isGlobal() && "caller should check MO.isGlobal");
unsigned TF = MO.getTargetFlags();
if (TF & ARMII::MO_LO16)
O << ":lower16:";
else if (TF & ARMII::MO_HI16)
O << ":upper16:";
else if (TF & ARMII::MO_LO_0_7)
O << ":lower0_7:";
else if (TF & ARMII::MO_LO_8_15)
O << ":lower8_15:";
else if (TF & ARMII::MO_HI_0_7)
O << ":upper0_7:";
else if (TF & ARMII::MO_HI_8_15)
O << ":upper8_15:";
GetARMGVSymbol(MO.getGlobal(), TF)->print(O, MAI);
printOffset(MO.getOffset(), O);
}
void ARMAsmPrinter::printOperand(const MachineInstr *MI, int 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!");
if(ARM::GPRPairRegClass.contains(Reg)) {
const MachineFunction &MF = *MI->getParent()->getParent();
const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
Reg = TRI->getSubReg(Reg, ARM::gsub_0);
}
O << ARMInstPrinter::getRegisterName(Reg);
break;
}
case MachineOperand::MO_Immediate: {
O << '#';
unsigned TF = MO.getTargetFlags();
if (TF == ARMII::MO_LO16)
O << ":lower16:";
else if (TF == ARMII::MO_HI16)
O << ":upper16:";
else if (TF == ARMII::MO_LO_0_7)
O << ":lower0_7:";
else if (TF == ARMII::MO_LO_8_15)
O << ":lower8_15:";
else if (TF == ARMII::MO_HI_0_7)
O << ":upper0_7:";
else if (TF == ARMII::MO_HI_8_15)
O << ":upper8_15:";
O << MO.getImm();
break;
}
case MachineOperand::MO_MachineBasicBlock:
MO.getMBB()->getSymbol()->print(O, MAI);
return;
case MachineOperand::MO_GlobalAddress: {
PrintSymbolOperand(MO, O);
break;
}
case MachineOperand::MO_ConstantPoolIndex:
assert(!MF->getSubtarget<ARMSubtarget>().genExecuteOnly() &&
"execute-only should not generate constant pools");
GetCPISymbol(MO.getIndex())->print(O, MAI);
break;
}
}
MCSymbol *ARMAsmPrinter::GetCPISymbol(unsigned CPID) const {
// The AsmPrinter::GetCPISymbol superclass method tries to use CPID as
// indexes in MachineConstantPool, which isn't in sync with indexes used here.
const DataLayout &DL = getDataLayout();
return OutContext.getOrCreateSymbol(Twine(DL.getInternalSymbolPrefix()) +
"CPI" + Twine(getFunctionNumber()) + "_" +
Twine(CPID));
}
//===--------------------------------------------------------------------===//
MCSymbol *ARMAsmPrinter::
GetARMJTIPICJumpTableLabel(unsigned uid) const {
const DataLayout &DL = getDataLayout();
SmallString<60> Name;
raw_svector_ostream(Name) << DL.getInternalSymbolPrefix() << "JTI"
<< getFunctionNumber() << '_' << uid;
return OutContext.getOrCreateSymbol(Name);
}
bool ARMAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNum,
const char *ExtraCode, raw_ostream &O) {
// 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:
// See if this is a generic print operand
return AsmPrinter::PrintAsmOperand(MI, OpNum, ExtraCode, O);
case 'P': // Print a VFP double precision register.
case 'q': // Print a NEON quad precision register.
printOperand(MI, OpNum, O);
return false;
case 'y': // Print a VFP single precision register as indexed double.
if (MI->getOperand(OpNum).isReg()) {
MCRegister Reg = MI->getOperand(OpNum).getReg().asMCReg();
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
// Find the 'd' register that has this 's' register as a sub-register,
// and determine the lane number.
for (MCPhysReg SR : TRI->superregs(Reg)) {
if (!ARM::DPRRegClass.contains(SR))
continue;
bool Lane0 = TRI->getSubReg(SR, ARM::ssub_0) == Reg;
O << ARMInstPrinter::getRegisterName(SR) << (Lane0 ? "[0]" : "[1]");
return false;
}
}
return true;
case 'B': // Bitwise inverse of integer or symbol without a preceding #.
if (!MI->getOperand(OpNum).isImm())
return true;
O << ~(MI->getOperand(OpNum).getImm());
return false;
case 'L': // The low 16 bits of an immediate constant.
if (!MI->getOperand(OpNum).isImm())
return true;
O << (MI->getOperand(OpNum).getImm() & 0xffff);
return false;
case 'M': { // A register range suitable for LDM/STM.
if (!MI->getOperand(OpNum).isReg())
return true;
const MachineOperand &MO = MI->getOperand(OpNum);
Register RegBegin = MO.getReg();
// This takes advantage of the 2 operand-ness of ldm/stm and that we've
// already got the operands in registers that are operands to the
// inline asm statement.
O << "{";
if (ARM::GPRPairRegClass.contains(RegBegin)) {
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
Register Reg0 = TRI->getSubReg(RegBegin, ARM::gsub_0);
O << ARMInstPrinter::getRegisterName(Reg0) << ", ";
RegBegin = TRI->getSubReg(RegBegin, ARM::gsub_1);
}
O << ARMInstPrinter::getRegisterName(RegBegin);
// FIXME: The register allocator not only may not have given us the
// registers in sequence, but may not be in ascending registers. This
// will require changes in the register allocator that'll need to be
// propagated down here if the operands change.
unsigned RegOps = OpNum + 1;
while (MI->getOperand(RegOps).isReg()) {
O << ", "
<< ARMInstPrinter::getRegisterName(MI->getOperand(RegOps).getReg());
RegOps++;
}
O << "}";
return false;
}
case 'R': // The most significant register of a pair.
case 'Q': { // The least significant register of a pair.
if (OpNum == 0)
return true;
const MachineOperand &FlagsOP = MI->getOperand(OpNum - 1);
if (!FlagsOP.isImm())
return true;
InlineAsm::Flag F(FlagsOP.getImm());
// This operand may not be the one that actually provides the register. If
// it's tied to a previous one then we should refer instead to that one
// for registers and their classes.
unsigned TiedIdx;
if (F.isUseOperandTiedToDef(TiedIdx)) {
for (OpNum = InlineAsm::MIOp_FirstOperand; TiedIdx; --TiedIdx) {
unsigned OpFlags = MI->getOperand(OpNum).getImm();
const InlineAsm::Flag F(OpFlags);
OpNum += F.getNumOperandRegisters() + 1;
}
F = InlineAsm::Flag(MI->getOperand(OpNum).getImm());
// Later code expects OpNum to be pointing at the register rather than
// the flags.
OpNum += 1;
}
const unsigned NumVals = F.getNumOperandRegisters();
unsigned RC;
bool FirstHalf;
const ARMBaseTargetMachine &ATM =
static_cast<const ARMBaseTargetMachine &>(TM);
// 'Q' should correspond to the low order register and 'R' to the high
// order register. Whether this corresponds to the upper or lower half
// depends on the endianness mode.
if (ExtraCode[0] == 'Q')
FirstHalf = ATM.isLittleEndian();
else
// ExtraCode[0] == 'R'.
FirstHalf = !ATM.isLittleEndian();
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
if (F.hasRegClassConstraint(RC) &&
ARM::GPRPairRegClass.hasSubClassEq(TRI->getRegClass(RC))) {
if (NumVals != 1)
return true;
const MachineOperand &MO = MI->getOperand(OpNum);
if (!MO.isReg())
return true;
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
Register Reg =
TRI->getSubReg(MO.getReg(), FirstHalf ? ARM::gsub_0 : ARM::gsub_1);
O << ARMInstPrinter::getRegisterName(Reg);
return false;
}
if (NumVals != 2)
return true;
unsigned RegOp = FirstHalf ? OpNum : OpNum + 1;
if (RegOp >= MI->getNumOperands())
return true;
const MachineOperand &MO = MI->getOperand(RegOp);
if (!MO.isReg())
return true;
Register Reg = MO.getReg();
O << ARMInstPrinter::getRegisterName(Reg);
return false;
}
case 'e': // The low doubleword register of a NEON quad register.
case 'f': { // The high doubleword register of a NEON quad register.
if (!MI->getOperand(OpNum).isReg())
return true;
Register Reg = MI->getOperand(OpNum).getReg();
if (!ARM::QPRRegClass.contains(Reg))
return true;
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
Register SubReg =
TRI->getSubReg(Reg, ExtraCode[0] == 'e' ? ARM::dsub_0 : ARM::dsub_1);
O << ARMInstPrinter::getRegisterName(SubReg);
return false;
}
// This modifier is not yet supported.
case 'h': // A range of VFP/NEON registers suitable for VLD1/VST1.
return true;
case 'H': { // The highest-numbered register of a pair.
const MachineOperand &MO = MI->getOperand(OpNum);
if (!MO.isReg())
return true;
const MachineFunction &MF = *MI->getParent()->getParent();
const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
Register Reg = MO.getReg();
if(!ARM::GPRPairRegClass.contains(Reg))
return false;
Reg = TRI->getSubReg(Reg, ARM::gsub_1);
O << ARMInstPrinter::getRegisterName(Reg);
return false;
}
}
}
printOperand(MI, OpNum, O);
return false;
}
bool ARMAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
unsigned OpNum, const char *ExtraCode,
raw_ostream &O) {
// 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]) {
case 'A': // A memory operand for a VLD1/VST1 instruction.
default: return true; // Unknown modifier.
case 'm': // The base register of a memory operand.
if (!MI->getOperand(OpNum).isReg())
return true;
O << ARMInstPrinter::getRegisterName(MI->getOperand(OpNum).getReg());
return false;
}
}
const MachineOperand &MO = MI->getOperand(OpNum);
assert(MO.isReg() && "unexpected inline asm memory operand");
O << "[" << ARMInstPrinter::getRegisterName(MO.getReg()) << "]";
return false;
}
static bool isThumb(const MCSubtargetInfo& STI) {
return STI.hasFeature(ARM::ModeThumb);
}
void ARMAsmPrinter::emitInlineAsmEnd(const MCSubtargetInfo &StartInfo,
const MCSubtargetInfo *EndInfo,
const MachineInstr *MI) {
// If either end mode is unknown (EndInfo == NULL) or different than
// the start mode, then restore the start mode.
const bool WasThumb = isThumb(StartInfo);
if (!EndInfo || WasThumb != isThumb(*EndInfo)) {
auto &TS =
static_cast<ARMTargetStreamer &>(*OutStreamer->getTargetStreamer());
if (WasThumb)
TS.emitCode16();
else
TS.emitCode32();
}
}
void ARMAsmPrinter::emitStartOfAsmFile(Module &M) {
const Triple &TT = TM.getTargetTriple();
auto &TS =
static_cast<ARMTargetStreamer &>(*OutStreamer->getTargetStreamer());
// Use unified assembler syntax.
TS.emitSyntaxUnified();
// Emit ARM Build Attributes
if (TT.isOSBinFormatELF())
emitAttributes();
// Use the triple's architecture and subarchitecture to determine
// if we're thumb for the purposes of the top level code16 state.
if (!M.getModuleInlineAsm().empty() && TT.isThumb())
TS.emitCode16();
}
static void
emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
MachineModuleInfoImpl::StubValueTy &MCSym) {
// L_foo$stub:
OutStreamer.emitLabel(StubLabel);
// .indirect_symbol _foo
OutStreamer.emitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
if (MCSym.getInt())
// External to current translation unit.
OutStreamer.emitIntValue(0, 4/*size*/);
else
// Internal to current translation unit.
//
// When we place the LSDA into the TEXT section, the type info
// pointers need to be indirect and pc-rel. We accomplish this by
// using NLPs; however, sometimes the types are local to the file.
// We need to fill in the value for the NLP in those cases.
OutStreamer.emitValue(
MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
4 /*size*/);
}
void ARMAsmPrinter::emitEndOfAsmFile(Module &M) {
const Triple &TT = TM.getTargetTriple();
if (TT.isOSBinFormatMachO()) {
// All darwin targets use mach-o.
const TargetLoweringObjectFileMachO &TLOFMacho =
static_cast<const TargetLoweringObjectFileMachO &>(getObjFileLowering());
MachineModuleInfoMachO &MMIMacho =
MMI->getObjFileInfo<MachineModuleInfoMachO>();
// Output non-lazy-pointers for external and common global variables.
MachineModuleInfoMachO::SymbolListTy Stubs = MMIMacho.GetGVStubList();
if (!Stubs.empty()) {
// Switch with ".non_lazy_symbol_pointer" directive.
OutStreamer->switchSection(TLOFMacho.getNonLazySymbolPointerSection());
emitAlignment(Align(4));
for (auto &Stub : Stubs)
emitNonLazySymbolPointer(*OutStreamer, Stub.first, Stub.second);
Stubs.clear();
OutStreamer->addBlankLine();
}
Stubs = MMIMacho.GetThreadLocalGVStubList();
if (!Stubs.empty()) {
// Switch with ".non_lazy_symbol_pointer" directive.
OutStreamer->switchSection(TLOFMacho.getThreadLocalPointerSection());
emitAlignment(Align(4));
for (auto &Stub : Stubs)
emitNonLazySymbolPointer(*OutStreamer, Stub.first, Stub.second);
Stubs.clear();
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();
}
// The last attribute to be emitted is ABI_optimization_goals
MCTargetStreamer &TS = *OutStreamer->getTargetStreamer();
ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
if (OptimizationGoals > 0 &&
(TT.isTargetAEABI() || TT.isTargetGNUAEABI() || TT.isTargetMuslAEABI()))
ATS.emitAttribute(ARMBuildAttrs::ABI_optimization_goals, OptimizationGoals);
OptimizationGoals = -1;
ATS.finishAttributeSection();
}
//===----------------------------------------------------------------------===//
// Helper routines for emitStartOfAsmFile() and emitEndOfAsmFile()
// FIXME:
// The following seem like one-off assembler flags, but they actually need
// to appear in the .ARM.attributes section in ELF.
// Instead of subclassing the MCELFStreamer, we do the work here.
// Returns true if all function definitions have the same function attribute
// value. It also returns true when the module has no functions.
static bool checkFunctionsAttributeConsistency(const Module &M, StringRef Attr,
StringRef Value) {
return !any_of(M, [&](const Function &F) {
if (F.isDeclaration())
return false;
return F.getFnAttribute(Attr).getValueAsString() != Value;
});
}
// Returns true if all functions definitions have the same denormal mode.
// It also returns true when the module has no functions.
static bool checkDenormalAttributeConsistency(const Module &M,
DenormalFPEnv Value) {
return !any_of(M, [&](const Function &F) {
if (F.isDeclaration())
return false;
return F.getDenormalFPEnv() != Value;
});
}
// Returns true if any function definition in the module has the strictfp
// attribute, which taints the whole module: such code may change the FP
// rounding mode at run time.
static bool checkModuleHasStrictFP(const Module &M) {
return any_of(M, [](const Function &F) {
return !F.isDeclaration() && F.isStrictFP();
});
}
// Returns true if all functions have different denormal modes.
static bool checkDenormalAttributeInconsistency(const Module &M) {
auto F = M.functions().begin();
auto E = M.functions().end();
if (F == E)
return false;
DenormalFPEnv Value = F->getDenormalFPEnv();
++F;
return std::any_of(F, E, [&](const Function &F) {
return !F.isDeclaration() && F.getDenormalFPEnv() != Value;
});
}
void ARMAsmPrinter::emitAttributes() {
MCTargetStreamer &TS = *OutStreamer->getTargetStreamer();
ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
ATS.emitTextAttribute(ARMBuildAttrs::conformance, "2.09");
ATS.switchVendor("aeabi");
// Compute ARM ELF Attributes based on the default subtarget that
// we'd have constructed. The existing ARM behavior isn't LTO clean
// anyhow.
// FIXME: For ifunc related functions we could iterate over and look
// for a feature string that doesn't match the default one.
const Triple &TT = TM.getTargetTriple();
StringRef CPU = TM.getTargetCPU();
StringRef FS = TM.getTargetFeatureString();
std::string ArchFS = ARM_MC::ParseARMTriple(TT, CPU);
if (!FS.empty()) {
if (!ArchFS.empty())
ArchFS = (Twine(ArchFS) + "," + FS).str();
else
ArchFS = std::string(FS);
}
const ARMBaseTargetMachine &ATM =
static_cast<const ARMBaseTargetMachine &>(TM);
FloatABI::ABIType FloatABI = ATM.getFloatABI(*MMI->getModule());
ARM::ARMABI ABI = ATM.getEffectiveABI(*MMI->getModule());
const ARMSubtarget STI(TT, std::string(CPU), ArchFS, ATM,
ATM.isLittleEndian(), FloatABI, ABI);
// Emit build attributes for the available hardware.
ATS.emitTargetAttributes(STI);
// RW data addressing.
if (isPositionIndependent()) {
ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_RW_data,
ARMBuildAttrs::AddressRWPCRel);
} else if (STI.isRWPI()) {
// RWPI specific attributes.
ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_RW_data,
ARMBuildAttrs::AddressRWSBRel);
}
// RO data addressing.
if (isPositionIndependent() || STI.isROPI()) {
ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_RO_data,
ARMBuildAttrs::AddressROPCRel);
}
// GOT use.
if (isPositionIndependent()) {
ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_GOT_use,
ARMBuildAttrs::AddressGOT);
} else {
ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_GOT_use,
ARMBuildAttrs::AddressDirect);
}
// Set FP Denormals.
if (auto *DM = mdconst::extract_or_null<ConstantInt>(
MMI->getModule()->getModuleFlag("arm-eabi-fp-denormal"))) {
if (unsigned TagVal = DM->getZExtValue())
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_denormal, TagVal);
} else if (checkDenormalAttributeConsistency(*MMI->getModule(),
DenormalMode::getPreserveSign()))
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_denormal,
ARMBuildAttrs::PreserveFPSign);
else if (checkDenormalAttributeConsistency(*MMI->getModule(),
DenormalMode::getPositiveZero()))
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_denormal,
ARMBuildAttrs::PositiveZero);
else if (checkDenormalAttributeInconsistency(*MMI->getModule()) ||
checkDenormalAttributeConsistency(*MMI->getModule(),
DenormalMode::getIEEE()))
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_denormal,
ARMBuildAttrs::IEEEDenormals);
else {
if (!STI.hasVFP2Base()) {
// When the target doesn't have an FPU (by design or
// intention), the assumptions made on the software support
// mirror that of the equivalent hardware support *if it
// existed*. For v7 and better we indicate that denormals are
// flushed preserving sign, and for V6 we indicate that
// denormals are flushed to positive zero.
if (STI.hasV7Ops())
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_denormal,
ARMBuildAttrs::PreserveFPSign);
} else if (STI.hasVFP3Base()) {
// In VFPv4, VFPv4U, VFPv3, or VFPv3U, it is preserved. That is,
// the sign bit of the zero matches the sign bit of the input or
// result that is being flushed to zero.
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_denormal,
ARMBuildAttrs::PreserveFPSign);
}
// For VFPv2 implementations it is implementation defined as
// to whether denormals are flushed to positive zero or to
// whatever the sign of zero is (ARM v7AR ARM 2.7.5). Historically
// LLVM has chosen to flush this to positive zero (most likely for
// GCC compatibility), so that's the chosen value here (the
// absence of its emission implies zero).
}
// Set FP exceptions and rounding
if (auto *Ex = mdconst::extract_or_null<ConstantInt>(
MMI->getModule()->getModuleFlag("arm-eabi-fp-exceptions"))) {
if (unsigned TagVal = Ex->getZExtValue())
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_exceptions, TagVal);
} else if (checkFunctionsAttributeConsistency(*MMI->getModule(),
"no-trapping-math", "true"))
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_exceptions,
ARMBuildAttrs::Not_Allowed);
else {
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_exceptions, ARMBuildAttrs::Allowed);
// If any function may change the FP rounding mode at run time the code
// cannot assume the default rounding, so emit the rounding attribute.
if (checkModuleHasStrictFP(*MMI->getModule()))
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_rounding, ARMBuildAttrs::Allowed);
}
// Generate ABI tags from module flags.
if (auto *NumModel = mdconst::extract_or_null<ConstantInt>(
MMI->getModule()->getModuleFlag("arm-eabi-fp-number-model"))) {
if (unsigned TagVal = NumModel->getZExtValue())
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_number_model, TagVal);
} else
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_number_model,
ARMBuildAttrs::AllowIEEE754);
// FIXME: add more flags to ARMBuildAttributes.h
// 8-bytes alignment stuff.
ATS.emitAttribute(ARMBuildAttrs::ABI_align_needed, 1);
ATS.emitAttribute(ARMBuildAttrs::ABI_align_preserved, 1);
// Hard float. Use both S and D registers and conform to AAPCS-VFP.
if (STI.isAAPCS_ABI() && STI.isTargetHardFloat())
ATS.emitAttribute(ARMBuildAttrs::ABI_VFP_args, ARMBuildAttrs::HardFPAAPCS);
// FIXME: To support emitting this build attribute as GCC does, the
// -mfp16-format option and associated plumbing must be
// supported. For now the __fp16 type is exposed by default, so this
// attribute should be emitted with value 1.
ATS.emitAttribute(ARMBuildAttrs::ABI_FP_16bit_format,
ARMBuildAttrs::FP16FormatIEEE);
if (const Module *SourceModule = MMI->getModule()) {
// ABI_PCS_wchar_t to indicate wchar_t width
// FIXME: There is no way to emit value 0 (wchar_t prohibited).
int WCharWidth = TM.getTargetTriple().getDefaultWCharSize();
if (auto WCharWidthValue = mdconst::extract_or_null<ConstantInt>(
SourceModule->getModuleFlag("wchar_size")))
WCharWidth = WCharWidthValue->getZExtValue();
assert((WCharWidth == 2 || WCharWidth == 4) &&
"wchar_t width must be 2 or 4 bytes");
ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_wchar_t, WCharWidth);
// ABI_enum_size to indicate enum width
// FIXME: There is no way to emit value 0 (enums prohibited) or value 3
// (all enums contain a value needing 32 bits to encode).
if (auto EnumWidthValue = mdconst::extract_or_null<ConstantInt>(
SourceModule->getModuleFlag("min_enum_size"))) {
int EnumWidth = EnumWidthValue->getZExtValue();
assert((EnumWidth == 1 || EnumWidth == 4) &&
"Minimum enum width must be 1 or 4 bytes");
int EnumBuildAttr = EnumWidth == 1 ? 1 : 2;
ATS.emitAttribute(ARMBuildAttrs::ABI_enum_size, EnumBuildAttr);
}
auto *PACValue = mdconst::extract_or_null<ConstantInt>(
SourceModule->getModuleFlag("sign-return-address"));
if (PACValue && PACValue->isOne()) {
// If "+pacbti" is used as an architecture extension,
// Tag_PAC_extension is emitted in
// ARMTargetStreamer::emitTargetAttributes().
if (!STI.hasPACBTI()) {
ATS.emitAttribute(ARMBuildAttrs::PAC_extension,
ARMBuildAttrs::AllowPACInNOPSpace);
}
ATS.emitAttribute(ARMBuildAttrs::PACRET_use, ARMBuildAttrs::PACRETUsed);
}
auto *BTIValue = mdconst::extract_or_null<ConstantInt>(
SourceModule->getModuleFlag("branch-target-enforcement"));
if (BTIValue && !BTIValue->isZero()) {
// If "+pacbti" is used as an architecture extension,
// Tag_BTI_extension is emitted in
// ARMTargetStreamer::emitTargetAttributes().
if (!STI.hasPACBTI()) {
ATS.emitAttribute(ARMBuildAttrs::BTI_extension,
ARMBuildAttrs::AllowBTIInNOPSpace);
}
ATS.emitAttribute(ARMBuildAttrs::BTI_use, ARMBuildAttrs::BTIUsed);
}
}
// We currently do not support using R9 as the TLS pointer.
if (STI.isRWPI())
ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_R9_use,
ARMBuildAttrs::R9IsSB);
else if (STI.isR9Reserved())
ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_R9_use,
ARMBuildAttrs::R9Reserved);
else
ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_R9_use,
ARMBuildAttrs::R9IsGPR);
}
//===----------------------------------------------------------------------===//
static MCSymbol *getBFLabel(StringRef Prefix, unsigned FunctionNumber,
unsigned LabelId, MCContext &Ctx) {
MCSymbol *Label = Ctx.getOrCreateSymbol(Twine(Prefix)
+ "BF" + Twine(FunctionNumber) + "_" + Twine(LabelId));
return Label;
}
static MCSymbol *getPICLabel(StringRef Prefix, unsigned FunctionNumber,
unsigned LabelId, MCContext &Ctx) {
MCSymbol *Label = Ctx.getOrCreateSymbol(Twine(Prefix)
+ "PC" + Twine(FunctionNumber) + "_" + Twine(LabelId));
return Label;
}
static uint8_t getModifierSpecifier(ARMCP::ARMCPModifier Modifier) {
switch (Modifier) {
case ARMCP::no_modifier:
return ARM::S_None;
case ARMCP::TLSGD:
return ARM::S_TLSGD;
case ARMCP::TPOFF:
return ARM::S_TPOFF;
case ARMCP::GOTTPOFF:
return ARM::S_GOTTPOFF;
case ARMCP::SBREL:
return ARM::S_SBREL;
case ARMCP::GOT_PREL:
return ARM::S_GOT_PREL;
case ARMCP::SECREL:
return ARM::S_COFF_SECREL;
}
llvm_unreachable("Invalid ARMCPModifier!");
}
MCSymbol *ARMAsmPrinter::GetARMGVSymbol(const GlobalValue *GV,
unsigned char TargetFlags) {
const Triple &TT = TM.getTargetTriple();
if (TT.isOSBinFormatMachO()) {
bool IsIndirect =
(TargetFlags & ARMII::MO_NONLAZY) && getTM().isGVIndirectSymbol(GV);
if (!IsIndirect)
return getSymbol(GV);
// FIXME: Remove this when Darwin transition to @GOT like syntax.
MCSymbol *MCSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
MachineModuleInfoMachO &MMIMachO =
MMI->getObjFileInfo<MachineModuleInfoMachO>();
MachineModuleInfoImpl::StubValueTy &StubSym =
GV->isThreadLocal() ? MMIMachO.getThreadLocalGVStubEntry(MCSym)
: MMIMachO.getGVStubEntry(MCSym);
if (!StubSym.getPointer())
StubSym = MachineModuleInfoImpl::StubValueTy(getSymbol(GV),
!GV->hasInternalLinkage());
return MCSym;
} else if (TT.isOSBinFormatCOFF()) {
assert(TT.isOSWindows() && "Windows is the only supported COFF target");
bool IsIndirect =
(TargetFlags & (ARMII::MO_DLLIMPORT | ARMII::MO_COFFSTUB));
if (!IsIndirect)
return getSymbol(GV);
SmallString<128> Name;
if (TargetFlags & ARMII::MO_DLLIMPORT)
Name = "__imp_";
else if (TargetFlags & ARMII::MO_COFFSTUB)
Name = ".refptr.";
getNameWithPrefix(Name, GV);
MCSymbol *MCSym = OutContext.getOrCreateSymbol(Name);
if (TargetFlags & ARMII::MO_COFFSTUB) {
MachineModuleInfoCOFF &MMICOFF =
MMI->getObjFileInfo<MachineModuleInfoCOFF>();
MachineModuleInfoImpl::StubValueTy &StubSym =
MMICOFF.getGVStubEntry(MCSym);
if (!StubSym.getPointer())
StubSym = MachineModuleInfoImpl::StubValueTy(getSymbol(GV), true);
}
return MCSym;
} else if (TT.isOSBinFormatELF()) {
return getSymbolPreferLocal(*GV);
}
llvm_unreachable("unexpected target");
}
void ARMAsmPrinter::emitMachineConstantPoolValue(
MachineConstantPoolValue *MCPV) {
const DataLayout &DL = getDataLayout();
int Size = DL.getTypeAllocSize(MCPV->getType());
ARMConstantPoolValue *ACPV = static_cast<ARMConstantPoolValue*>(MCPV);
if (ACPV->isPromotedGlobal()) {
// This constant pool entry is actually a global whose storage has been
// promoted into the constant pool. This global may be referenced still
// by debug information, and due to the way AsmPrinter is set up, the debug
// info is immutable by the time we decide to promote globals to constant
// pools. Because of this, we need to ensure we emit a symbol for the global
// with private linkage (the default) so debug info can refer to it.
//
// However, if this global is promoted into several functions we must ensure
// we don't try and emit duplicate symbols!
auto *ACPC = cast<ARMConstantPoolConstant>(ACPV);
for (const auto *GV : ACPC->promotedGlobals()) {
if (!EmittedPromotedGlobalLabels.count(GV)) {
MCSymbol *GVSym = getSymbol(GV);
OutStreamer->emitLabel(GVSym);
EmittedPromotedGlobalLabels.insert(GV);
}
}
return emitGlobalConstant(DL, ACPC->getPromotedGlobalInit());
}
MCSymbol *MCSym;
if (ACPV->isLSDA()) {
MCSym = getMBBExceptionSym(MF->front());
} else if (ACPV->isBlockAddress()) {
const BlockAddress *BA =
cast<ARMConstantPoolConstant>(ACPV)->getBlockAddress();
MCSym = GetBlockAddressSymbol(BA);
} else if (ACPV->isGlobalValue()) {
const GlobalValue *GV = cast<ARMConstantPoolConstant>(ACPV)->getGV();
// On Darwin, const-pool entries may get the "FOO$non_lazy_ptr" mangling, so
// flag the global as MO_NONLAZY.
unsigned char TF =
TM.getTargetTriple().isOSBinFormatMachO() ? ARMII::MO_NONLAZY : 0;
MCSym = GetARMGVSymbol(GV, TF);
// For dso_local weak symbols in ELF PIC mode, the assembler would eagerly
// resolve a PC-relative expression like sym-(LPC+8) when the symbol and
// reference are in the same section, preventing the linker from overriding
// a weak definition with a non-weak definition from another section. Use a
// .reloc directive rather than a fixup to force the generation of a
// relocation (R_ARM_REL32) so the linker can perform the override. This is
// restricted to dso_local, non-TLS symbols: a preemptible/external weak
// symbol (e.g. an extern_weak reference) must use the GOT, as R_ARM_REL32
// against an external symbol cannot be used when making a shared object;
// and TLS symbols require TLS-specific relocations, not R_ARM_REL32.
if (GV->isWeakForLinker() && GV->isDSOLocal() && !GV->isThreadLocal() &&
TM.getTargetTriple().isOSBinFormatELF() && TM.isPositionIndependent() &&
ACPV->getPCAdjustment() != 0) {
MCSymbol *CPILabel = OutContext.createTempSymbol();
OutStreamer->emitLabel(CPILabel);
// Emit local-only expression: CPILabel - (LPC+PCAdj)
const MCExpr *LocalExpr = MCSymbolRefExpr::create(CPILabel, OutContext);
MCSymbol *PCLabel =
getPICLabel(DL.getInternalSymbolPrefix(), getFunctionNumber(),
ACPV->getLabelId(), OutContext);
const MCExpr *PCRelExpr = MCSymbolRefExpr::create(PCLabel, OutContext);
PCRelExpr = MCBinaryExpr::createAdd(
PCRelExpr,
MCConstantExpr::create(ACPV->getPCAdjustment(), OutContext),
OutContext);
LocalExpr = MCBinaryExpr::createSub(LocalExpr, PCRelExpr, OutContext);
OutStreamer->emitValue(LocalExpr, Size);
// Emit .reloc to force linker resolution of the weak symbol.
const MCExpr *CPIExpr = MCSymbolRefExpr::create(CPILabel, OutContext);
const MCExpr *SymExpr = MCSymbolRefExpr::create(MCSym, OutContext);
OutStreamer->emitRelocDirective(*CPIExpr, "R_ARM_REL32", SymExpr,
SMLoc());
return;
}
} else if (ACPV->isMachineBasicBlock()) {
const MachineBasicBlock *MBB = cast<ARMConstantPoolMBB>(ACPV)->getMBB();
MCSym = MBB->getSymbol();
} else {
assert(ACPV->isExtSymbol() && "unrecognized constant pool value");
auto Sym = cast<ARMConstantPoolSymbol>(ACPV)->getSymbol();
MCSym = GetExternalSymbolSymbol(Sym);
}
// Create an MCSymbol for the reference.
const MCExpr *Expr = MCSymbolRefExpr::create(
MCSym, getModifierSpecifier(ACPV->getModifier()), OutContext);
if (ACPV->getPCAdjustment()) {
MCSymbol *PCLabel =
getPICLabel(DL.getInternalSymbolPrefix(), getFunctionNumber(),
ACPV->getLabelId(), OutContext);
const MCExpr *PCRelExpr = MCSymbolRefExpr::create(PCLabel, OutContext);
PCRelExpr =
MCBinaryExpr::createAdd(PCRelExpr,
MCConstantExpr::create(ACPV->getPCAdjustment(),
OutContext),
OutContext);
if (ACPV->mustAddCurrentAddress()) {
// We want "(<expr> - .)", but MC doesn't have a concept of the '.'
// label, so just emit a local label end reference that instead.
MCSymbol *DotSym = OutContext.createTempSymbol();
OutStreamer->emitLabel(DotSym);
const MCExpr *DotExpr = MCSymbolRefExpr::create(DotSym, OutContext);
PCRelExpr = MCBinaryExpr::createSub(PCRelExpr, DotExpr, OutContext);
}
Expr = MCBinaryExpr::createSub(Expr, PCRelExpr, OutContext);
}
OutStreamer->emitValue(Expr, Size);
}
void ARMAsmPrinter::emitJumpTableAddrs(const MachineInstr *MI) {
const MachineOperand &MO1 = MI->getOperand(1);
unsigned JTI = MO1.getIndex();
// Make sure the Thumb jump table is 4-byte aligned. This will be a nop for
// ARM mode tables.
emitAlignment(Align(4));
// Emit a label for the jump table.
MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel(JTI);
OutStreamer->emitLabel(JTISymbol);
// Mark the jump table as data-in-code.
OutStreamer->emitDataRegion(MCDR_DataRegionJT32);
// Emit each entry of the table.
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
for (MachineBasicBlock *MBB : JTBBs) {
// Construct an MCExpr for the entry. We want a value of the form:
// (BasicBlockAddr - TableBeginAddr)
//
// For example, a table with entries jumping to basic blocks BB0 and BB1
// would look like:
// LJTI_0_0:
// .word (LBB0 - LJTI_0_0)
// .word (LBB1 - LJTI_0_0)
const MCExpr *Expr = MCSymbolRefExpr::create(MBB->getSymbol(), OutContext);
const ARMSubtarget &STI = MF->getSubtarget<ARMSubtarget>();
if (isPositionIndependent() || STI.isROPI())
Expr = MCBinaryExpr::createSub(Expr, MCSymbolRefExpr::create(JTISymbol,
OutContext),
OutContext);
// If we're generating a table of Thumb addresses in static relocation
// model, we need to add one to keep interworking correctly.
else if (AFI->isThumbFunction())
Expr = MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(1,OutContext),
OutContext);
OutStreamer->emitValue(Expr, 4);
}
// Mark the end of jump table data-in-code region.
OutStreamer->emitDataRegion(MCDR_DataRegionEnd);
}
void ARMAsmPrinter::emitJumpTableInsts(const MachineInstr *MI) {
const MachineOperand &MO1 = MI->getOperand(1);
unsigned JTI = MO1.getIndex();
// Make sure the Thumb jump table is 4-byte aligned. This will be a nop for
// ARM mode tables.
emitAlignment(Align(4));
// Emit a label for the jump table.
MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel(JTI);
OutStreamer->emitLabel(JTISymbol);
// Emit each entry of the table.
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
for (MachineBasicBlock *MBB : JTBBs) {
const MCExpr *MBBSymbolExpr = MCSymbolRefExpr::create(MBB->getSymbol(),
OutContext);
// If this isn't a TBB or TBH, the entries are direct branch instructions.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2B)
.addExpr(MBBSymbolExpr)
.addImm(ARMCC::AL)
.addReg(0));
}
}
void ARMAsmPrinter::emitJumpTableTBInst(const MachineInstr *MI,
unsigned OffsetWidth) {
assert((OffsetWidth == 1 || OffsetWidth == 2) && "invalid tbb/tbh width");
const MachineOperand &MO1 = MI->getOperand(1);
unsigned JTI = MO1.getIndex();
const ARMSubtarget &STI = MF->getSubtarget<ARMSubtarget>();
if (STI.isThumb1Only())
emitAlignment(Align(4));
MCSymbol *JTISymbol = GetARMJTIPICJumpTableLabel(JTI);
OutStreamer->emitLabel(JTISymbol);
// Emit each entry of the table.
const MachineJumpTableInfo *MJTI = MF->getJumpTableInfo();
const std::vector<MachineJumpTableEntry> &JT = MJTI->getJumpTables();
const std::vector<MachineBasicBlock*> &JTBBs = JT[JTI].MBBs;
// Mark the jump table as data-in-code.
OutStreamer->emitDataRegion(OffsetWidth == 1 ? MCDR_DataRegionJT8
: MCDR_DataRegionJT16);
for (auto *MBB : JTBBs) {
const MCExpr *MBBSymbolExpr = MCSymbolRefExpr::create(MBB->getSymbol(),
OutContext);
// Otherwise it's an offset from the dispatch instruction. Construct an
// MCExpr for the entry. We want a value of the form:
// (BasicBlockAddr - TBBInstAddr + 4) / 2
//
// For example, a TBB table with entries jumping to basic blocks BB0 and BB1
// would look like:
// LJTI_0_0:
// .byte (LBB0 - (LCPI0_0 + 4)) / 2
// .byte (LBB1 - (LCPI0_0 + 4)) / 2
// where LCPI0_0 is a label defined just before the TBB instruction using
// this table.
MCSymbol *TBInstPC = GetCPISymbol(MI->getOperand(0).getImm());
const MCExpr *Expr = MCBinaryExpr::createAdd(
MCSymbolRefExpr::create(TBInstPC, OutContext),
MCConstantExpr::create(4, OutContext), OutContext);
Expr = MCBinaryExpr::createSub(MBBSymbolExpr, Expr, OutContext);
Expr = MCBinaryExpr::createDiv(Expr, MCConstantExpr::create(2, OutContext),
OutContext);
OutStreamer->emitValue(Expr, OffsetWidth);
}
// Mark the end of jump table data-in-code region. 32-bit offsets use
// actual branch instructions here, so we don't mark those as a data-region
// at all.
OutStreamer->emitDataRegion(MCDR_DataRegionEnd);
// Make sure the next instruction is 2-byte aligned.
emitAlignment(Align(2));
}
std::tuple<const MCSymbol *, uint64_t, const MCSymbol *,
codeview::JumpTableEntrySize>
ARMAsmPrinter::getCodeViewJumpTableInfo(int JTI,
const MachineInstr *BranchInstr,
const MCSymbol *BranchLabel) const {
codeview::JumpTableEntrySize EntrySize;
const MCSymbol *BaseLabel;
uint64_t BaseOffset = 0;
switch (BranchInstr->getOpcode()) {
case ARM::BR_JTadd:
case ARM::BR_JTr:
case ARM::tBR_JTr:
// Word relative to the jump table address.
EntrySize = codeview::JumpTableEntrySize::UInt32;
BaseLabel = GetARMJTIPICJumpTableLabel(JTI);
break;
case ARM::tTBH_JT:
case ARM::t2TBH_JT:
// half-word shifted left, relative to *after* the branch instruction.
EntrySize = codeview::JumpTableEntrySize::UInt16ShiftLeft;
BranchLabel = GetCPISymbol(BranchInstr->getOperand(3).getImm());
BaseLabel = BranchLabel;
BaseOffset = 4;
break;
case ARM::tTBB_JT:
case ARM::t2TBB_JT:
// byte shifted left, relative to *after* the branch instruction.
EntrySize = codeview::JumpTableEntrySize::UInt8ShiftLeft;
BranchLabel = GetCPISymbol(BranchInstr->getOperand(3).getImm());
BaseLabel = BranchLabel;
BaseOffset = 4;
break;
case ARM::t2BR_JT:
// Direct jump.
BaseLabel = nullptr;
EntrySize = codeview::JumpTableEntrySize::Pointer;
break;
default:
llvm_unreachable("Unknown jump table instruction");
}
return std::make_tuple(BaseLabel, BaseOffset, BranchLabel, EntrySize);
}
void ARMAsmPrinter::EmitUnwindingInstruction(const MachineInstr *MI) {
assert(MI->getFlag(MachineInstr::FrameSetup) &&
"Only instruction which are involved into frame setup code are allowed");
MCTargetStreamer &TS = *OutStreamer->getTargetStreamer();
ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
const MachineFunction &MF = *MI->getParent()->getParent();
const TargetRegisterInfo *TargetRegInfo =
MF.getSubtarget().getRegisterInfo();
const MachineRegisterInfo &MachineRegInfo = MF.getRegInfo();
Register FramePtr = TargetRegInfo->getFrameRegister(MF);
unsigned Opc = MI->getOpcode();
unsigned SrcReg, DstReg;
switch (Opc) {
case ARM::tPUSH:
// special case: tPUSH does not have src/dst regs.
SrcReg = DstReg = ARM::SP;
break;
case ARM::tLDRpci:
case ARM::t2MOVi16:
case ARM::t2MOVTi16:
case ARM::tMOVi8:
case ARM::tADDi8:
case ARM::tLSLri:
// special cases:
// 1) for Thumb1 code we sometimes materialize the constant via constpool
// load.
// 2) for Thumb1 execute only code we materialize the constant via the
// following pattern:
// movs r3, #:upper8_15:<const>
// lsls r3, #8
// adds r3, #:upper0_7:<const>
// lsls r3, #8
// adds r3, #:lower8_15:<const>
// lsls r3, #8
// adds r3, #:lower0_7:<const>
// So we need to special-case MOVS, ADDS and LSLS, and keep track of
// where we are in the sequence with the simplest of state machines.
// 3) for Thumb2 execute only code we materialize the constant via
// immediate constants in 2 separate instructions (MOVW/MOVT).
SrcReg = ~0U;
DstReg = MI->getOperand(0).getReg();
break;
case ARM::VMRS:
SrcReg = ARM::FPSCR;
DstReg = MI->getOperand(0).getReg();
break;
case ARM::VMRS_FPEXC:
SrcReg = ARM::FPEXC;
DstReg = MI->getOperand(0).getReg();
break;
default:
SrcReg = MI->getOperand(1).getReg();
DstReg = MI->getOperand(0).getReg();
break;
}
// Try to figure out the unwinding opcode out of src / dst regs.
if (MI->mayStore()) {
// Register saves.
assert(DstReg == ARM::SP &&
"Only stack pointer as a destination reg is supported");
SmallVector<MCRegister, 4> RegList;
// Skip src & dst reg, and pred ops.
unsigned StartOp = 2 + 2;
// Use all the operands.
unsigned NumOffset = 0;
// Amount of SP adjustment folded into a push, before the
// registers are stored (pad at higher addresses).
unsigned PadBefore = 0;
// Amount of SP adjustment folded into a push, after the
// registers are stored (pad at lower addresses).
unsigned PadAfter = 0;
switch (Opc) {
default:
MI->print(errs());
llvm_unreachable("Unsupported opcode for unwinding information");
case ARM::tPUSH:
// Special case here: no src & dst reg, but two extra imp ops.
StartOp = 2; NumOffset = 2;
[[fallthrough]];
case ARM::STMDB_UPD:
case ARM::t2STMDB_UPD:
case ARM::VSTMDDB_UPD:
assert(SrcReg == ARM::SP &&
"Only stack pointer as a source reg is supported");
for (unsigned i = StartOp, NumOps = MI->getNumOperands() - NumOffset;
i != NumOps; ++i) {
const MachineOperand &MO = MI->getOperand(i);
// Actually, there should never be any impdef stuff here. Skip it
// temporary to workaround PR11902.
if (MO.isImplicit())
continue;
// Registers, pushed as a part of folding an SP update into the
// push instruction are marked as undef and should not be
// restored when unwinding, because the function can modify the
// corresponding stack slots.
if (MO.isUndef()) {
assert(RegList.empty() &&
"Pad registers must come before restored ones");
unsigned Width =
TargetRegInfo->getRegSizeInBits(MO.getReg(), MachineRegInfo) / 8;
PadAfter += Width;
continue;
}
// Check for registers that are remapped (for a Thumb1 prologue that
// saves high registers).
Register Reg = MO.getReg();
if (unsigned RemappedReg = AFI->EHPrologueRemappedRegs.lookup(Reg))
Reg = RemappedReg;
RegList.push_back(Reg);
}
break;
case ARM::STR_PRE_IMM:
case ARM::STR_PRE_REG:
case ARM::t2STR_PRE:
assert(MI->getOperand(2).getReg() == ARM::SP &&
"Only stack pointer as a source reg is supported");
if (unsigned RemappedReg = AFI->EHPrologueRemappedRegs.lookup(SrcReg))
SrcReg = RemappedReg;
RegList.push_back(SrcReg);
break;
case ARM::t2STRD_PRE:
assert(MI->getOperand(3).getReg() == ARM::SP &&
"Only stack pointer as a source reg is supported");
SrcReg = MI->getOperand(1).getReg();
if (unsigned RemappedReg = AFI->EHPrologueRemappedRegs.lookup(SrcReg))
SrcReg = RemappedReg;
RegList.push_back(SrcReg);
SrcReg = MI->getOperand(2).getReg();
if (unsigned RemappedReg = AFI->EHPrologueRemappedRegs.lookup(SrcReg))
SrcReg = RemappedReg;
RegList.push_back(SrcReg);
PadBefore = -MI->getOperand(4).getImm() - 8;
break;
}
if (MAI.getExceptionHandlingType() == ExceptionHandling::ARM) {
if (PadBefore)
ATS.emitPad(PadBefore);
ATS.emitRegSave(RegList, Opc == ARM::VSTMDDB_UPD);
// Account for the SP adjustment, folded into the push.
if (PadAfter)
ATS.emitPad(PadAfter);
}
} else {
// Changes of stack / frame pointer.
if (SrcReg == ARM::SP) {
int64_t Offset = 0;
switch (Opc) {
default:
MI->print(errs());
llvm_unreachable("Unsupported opcode for unwinding information");
case ARM::tLDRspi:
// Used to restore LR in a prologue which uses it as a temporary, has
// no effect on unwind tables.
return;
case ARM::MOVr:
case ARM::tMOVr:
Offset = 0;
break;
case ARM::ADDri:
case ARM::t2ADDri:
case ARM::t2ADDri12:
case ARM::t2ADDspImm:
case ARM::t2ADDspImm12:
Offset = -MI->getOperand(2).getImm();
break;
case ARM::SUBri:
case ARM::t2SUBri:
case ARM::t2SUBri12:
case ARM::t2SUBspImm:
case ARM::t2SUBspImm12:
Offset = MI->getOperand(2).getImm();
break;
case ARM::tSUBspi:
Offset = MI->getOperand(2).getImm()*4;
break;
case ARM::tADDspi:
case ARM::tADDrSPi:
Offset = -MI->getOperand(2).getImm()*4;
break;
case ARM::tADDhirr:
Offset =
-AFI->EHPrologueOffsetInRegs.lookup(MI->getOperand(2).getReg());
break;
}
if (MAI.getExceptionHandlingType() == ExceptionHandling::ARM) {
if (DstReg == FramePtr && FramePtr != ARM::SP)
// Set-up of the frame pointer. Positive values correspond to "add"
// instruction.
ATS.emitSetFP(FramePtr, ARM::SP, -Offset);
else if (DstReg == ARM::SP) {
// Change of SP by an offset. Positive values correspond to "sub"
// instruction.
ATS.emitPad(Offset);
} else {
// Move of SP to a register. Positive values correspond to an "add"
// instruction.
ATS.emitMovSP(DstReg, -Offset);
}
}
} else if (DstReg == ARM::SP) {
MI->print(errs());
llvm_unreachable("Unsupported opcode for unwinding information");
} else {
int64_t Offset = 0;
switch (Opc) {
case ARM::tMOVr:
// If a Thumb1 function spills r8-r11, we copy the values to low
// registers before pushing them. Record the copy so we can emit the
// correct ".save" later.
AFI->EHPrologueRemappedRegs[DstReg] = SrcReg;
break;
case ARM::VMRS:
case ARM::VMRS_FPEXC:
// If a function spills FPSCR or FPEXC, we copy the values to low
// registers before pushing them. However, we can't issue annotations
// for FP status registers because ".save" requires GPR registers, and
// ".vsave" requires DPR registers, so don't record the copy and simply
// emit annotations for the source registers used for the store.
break;
case ARM::tLDRpci: {
// Grab the constpool index and check, whether it corresponds to
// original or cloned constpool entry.
unsigned CPI = MI->getOperand(1).getIndex();
const MachineConstantPool *MCP = MF.getConstantPool();
if (CPI >= MCP->getConstants().size())
CPI = AFI->getOriginalCPIdx(CPI);
assert(CPI != -1U && "Invalid constpool index");
// Derive the actual offset.
const MachineConstantPoolEntry &CPE = MCP->getConstants()[CPI];
assert(!CPE.isMachineConstantPoolEntry() && "Invalid constpool entry");
Offset = cast<ConstantInt>(CPE.Val.ConstVal)->getSExtValue();
AFI->EHPrologueOffsetInRegs[DstReg] = Offset;
break;
}
case ARM::t2MOVi16:
Offset = MI->getOperand(1).getImm();
AFI->EHPrologueOffsetInRegs[DstReg] = Offset;
break;
case ARM::t2MOVTi16:
Offset = MI->getOperand(2).getImm();
AFI->EHPrologueOffsetInRegs[DstReg] |= (Offset << 16);
break;
case ARM::tMOVi8:
Offset = MI->getOperand(2).getImm();
AFI->EHPrologueOffsetInRegs[DstReg] = Offset;
break;
case ARM::tLSLri:
assert(MI->getOperand(3).getImm() == 8 &&
"The shift amount is not equal to 8");
assert(MI->getOperand(2).getReg() == MI->getOperand(0).getReg() &&
"The source register is not equal to the destination register");
AFI->EHPrologueOffsetInRegs[DstReg] <<= 8;
break;
case ARM::tADDi8:
assert(MI->getOperand(2).getReg() == MI->getOperand(0).getReg() &&
"The source register is not equal to the destination register");
Offset = MI->getOperand(3).getImm();
AFI->EHPrologueOffsetInRegs[DstReg] += Offset;
break;
case ARM::t2PAC:
case ARM::t2PACBTI:
AFI->EHPrologueRemappedRegs[ARM::R12] = ARM::RA_AUTH_CODE;
break;
default:
MI->print(errs());
llvm_unreachable("Unsupported opcode for unwinding information");
}
}
}
}
// Simple pseudo-instructions have their lowering (with expansion to real
// instructions) auto-generated.
#include "ARMGenMCPseudoLowering.inc"
// Helper function to check if a register is live (used as an implicit operand)
// in the given call instruction.
static bool isRegisterLiveInCall(const MachineInstr &Call, MCRegister Reg) {
for (const MachineOperand &MO : Call.implicit_operands()) {
if (MO.isReg() && MO.getReg() == Reg && MO.isUse()) {
return true;
}
}
return false;
}
void ARMAsmPrinter::EmitKCFI_CHECK_ARM32(Register AddrReg, int64_t Type,
const MachineInstr &Call,
int64_t PrefixNops) {
// Choose scratch register: r12 primary, r3 if target is r12.
unsigned ScratchReg = ARM::R12;
if (AddrReg == ARM::R12) {
ScratchReg = ARM::R3;
}
// Calculate ESR for ARM mode (16-bit): 0x8000 | (scratch_reg << 5) | addr_reg
// Note: scratch_reg is always 0x1F since the EOR sequence clobbers it.
const ARMBaseRegisterInfo *TRI = static_cast<const ARMBaseRegisterInfo *>(
MF->getSubtarget().getRegisterInfo());
unsigned AddrIndex = TRI->getEncodingValue(AddrReg);
unsigned ESR = 0x8000 | (31 << 5) | (AddrIndex & 31);
// Check if r3 is live and needs to be spilled.
bool NeedSpillR3 =
(ScratchReg == ARM::R3) && isRegisterLiveInCall(Call, ARM::R3);
// If we need to spill r3, push it first.
if (NeedSpillR3) {
// push {r3}
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::STMDB_UPD)
.addReg(ARM::SP)
.addReg(ARM::SP)
.addImm(ARMCC::AL)
.addReg(0)
.addReg(ARM::R3));
}
// Clear bit 0 of target address to handle Thumb function pointers.
// In 32-bit ARM, function pointers may have the low bit set to indicate
// Thumb state when ARM/Thumb interworking is enabled (ARMv4T and later).
// We need to clear it to avoid an alignment fault when loading.
// bic scratch, target, #1
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::BICri)
.addReg(ScratchReg)
.addReg(AddrReg)
.addImm(1)
.addImm(ARMCC::AL)
.addReg(0)
.addReg(0));
// ldr scratch, [scratch, #-(PrefixNops * 4 + 4)]
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::LDRi12)
.addReg(ScratchReg)
.addReg(ScratchReg)
.addImm(-(PrefixNops * 4 + 4))
.addImm(ARMCC::AL)
.addReg(0));
// Each EOR instruction XORs one byte of the type, shifted to its position.
for (int i = 0; i < 4; i++) {
uint8_t byte = (Type >> (i * 8)) & 0xFF;
uint32_t imm = byte << (i * 8);
bool isLast = (i == 3);
// Encode as ARM modified immediate.
int SOImmVal = ARM_AM::getSOImmVal(imm);
assert(SOImmVal != -1 &&
"Cannot encode immediate as ARM modified immediate");
// eor[s] scratch, scratch, #imm (last one sets flags with CPSR)
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::EORri)
.addReg(ScratchReg)
.addReg(ScratchReg)
.addImm(SOImmVal)
.addImm(ARMCC::AL)
.addReg(0)
.addReg(isLast ? ARM::CPSR : Register()));
}
// If we spilled r3, restore it immediately after the comparison.
// This must happen before the branch so r3 is valid on both paths.
if (NeedSpillR3) {
// pop {r3}
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::LDMIA_UPD)
.addReg(ARM::SP)
.addReg(ARM::SP)
.addImm(ARMCC::AL)
.addReg(0)
.addReg(ARM::R3));
}
// beq .Lpass (branch if types match, i.e., scratch is zero)
MCSymbol *Pass = OutContext.createTempSymbol();
EmitToStreamer(*OutStreamer,
MCInstBuilder(ARM::Bcc)
.addExpr(MCSymbolRefExpr::create(Pass, OutContext))
.addImm(ARMCC::EQ)
.addReg(ARM::CPSR));
// udf #ESR (trap with encoded diagnostic)
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::UDF).addImm(ESR));
OutStreamer->emitLabel(Pass);
}
void ARMAsmPrinter::EmitKCFI_CHECK_Thumb2(Register AddrReg, int64_t Type,
const MachineInstr &Call,
int64_t PrefixNops) {
// Choose scratch register: r12 primary, r3 if target is r12.
unsigned ScratchReg = ARM::R12;
if (AddrReg == ARM::R12) {
ScratchReg = ARM::R3;
}
// Calculate ESR for Thumb mode (8-bit): 0x80 | addr_reg
// Bit 7: KCFI trap indicator
// Bits 6-5: Reserved
// Bits 4-0: Address register encoding
const ARMBaseRegisterInfo *TRI = static_cast<const ARMBaseRegisterInfo *>(
MF->getSubtarget().getRegisterInfo());
unsigned AddrIndex = TRI->getEncodingValue(AddrReg);
unsigned ESR = 0x80 | (AddrIndex & 0x1F);
// Check if r3 is live and needs to be spilled.
bool NeedSpillR3 =
(ScratchReg == ARM::R3) && isRegisterLiveInCall(Call, ARM::R3);
// If we need to spill r3, push it first.
if (NeedSpillR3) {
// push {r3}
EmitToStreamer(
*OutStreamer,
MCInstBuilder(ARM::tPUSH).addImm(ARMCC::AL).addReg(0).addReg(ARM::R3));
}
// Clear bit 0 of target address to handle Thumb function pointers.
// In 32-bit ARM, function pointers may have the low bit set to indicate
// Thumb state when ARM/Thumb interworking is enabled (ARMv4T and later).
// We need to clear it to avoid an alignment fault when loading.
// bic scratch, target, #1
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2BICri)
.addReg(ScratchReg)
.addReg(AddrReg)
.addImm(1)
.addImm(ARMCC::AL)
.addReg(0)
.addReg(0));
// ldr scratch, [scratch, #-(PrefixNops * 4 + 4)]
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2LDRi8)
.addReg(ScratchReg)
.addReg(ScratchReg)
.addImm(-(PrefixNops * 4 + 4))
.addImm(ARMCC::AL)
.addReg(0));
// Each EOR instruction XORs one byte of the type, shifted to its position.
for (int i = 0; i < 4; i++) {
uint8_t byte = (Type >> (i * 8)) & 0xFF;
uint32_t imm = byte << (i * 8);
bool isLast = (i == 3);
// Verify the immediate can be encoded as Thumb2 modified immediate.
assert(ARM_AM::getT2SOImmVal(imm) != -1 &&
"Cannot encode immediate as Thumb2 modified immediate");
// eor[s] scratch, scratch, #imm (last one sets flags with CPSR)
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2EORri)
.addReg(ScratchReg)
.addReg(ScratchReg)
.addImm(imm)
.addImm(ARMCC::AL)
.addReg(0)
.addReg(isLast ? ARM::CPSR : Register()));
}
// If we spilled r3, restore it immediately after the comparison.
// This must happen before the branch so r3 is valid on both paths.
if (NeedSpillR3) {
// pop {r3}
EmitToStreamer(
*OutStreamer,
MCInstBuilder(ARM::tPOP).addImm(ARMCC::AL).addReg(0).addReg(ARM::R3));
}
// beq .Lpass (branch if types match, i.e., scratch is zero)
MCSymbol *Pass = OutContext.createTempSymbol();
EmitToStreamer(*OutStreamer,
MCInstBuilder(ARM::t2Bcc)
.addExpr(MCSymbolRefExpr::create(Pass, OutContext))
.addImm(ARMCC::EQ)
.addReg(ARM::CPSR));
// udf #ESR (trap with encoded diagnostic)
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tUDF).addImm(ESR));
OutStreamer->emitLabel(Pass);
}
void ARMAsmPrinter::EmitKCFI_CHECK_Thumb1(Register AddrReg, int64_t Type,
const MachineInstr &Call,
int64_t PrefixNops) {
// For Thumb1, use R2 unconditionally as scratch register (a low register
// required for tLDRi). R3 is used for building the type hash.
unsigned ScratchReg = ARM::R2;
unsigned TempReg = ARM::R3;
// Check if r3 is live and needs to be spilled.
bool NeedSpillR3 = isRegisterLiveInCall(Call, ARM::R3);
// Spill r3 if needed
if (NeedSpillR3) {
EmitToStreamer(
*OutStreamer,
MCInstBuilder(ARM::tPUSH).addImm(ARMCC::AL).addReg(0).addReg(ARM::R3));
}
// Check if r2 is live and needs to be spilled.
bool NeedSpillR2 = isRegisterLiveInCall(Call, ARM::R2);
// Push R2 if it's live
if (NeedSpillR2) {
EmitToStreamer(
*OutStreamer,
MCInstBuilder(ARM::tPUSH).addImm(ARMCC::AL).addReg(0).addReg(ARM::R2));
}
// Clear bit 0 from target address
// TempReg (R3) is used first as helper for BIC, then later for building type
// hash.
// movs temp, #1
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tMOVi8)
.addReg(TempReg)
.addReg(ARM::CPSR)
.addImm(1)
.addImm(ARMCC::AL)
.addReg(0));
// mov scratch, target
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tMOVr)
.addReg(ScratchReg)
.addReg(AddrReg)
.addImm(ARMCC::AL));
// bics scratch, temp (scratch = scratch & ~temp)
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tBIC)
.addReg(ScratchReg)
.addReg(ARM::CPSR)
.addReg(ScratchReg)
.addReg(TempReg)
.addImm(ARMCC::AL)
.addReg(0));
// Load type hash. Thumb1 doesn't support negative offsets, so subtract.
int offset = PrefixNops * 4 + 4;
// subs scratch, #offset
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tSUBi8)
.addReg(ScratchReg)
.addReg(ARM::CPSR)
.addReg(ScratchReg)
.addImm(offset)
.addImm(ARMCC::AL)
.addReg(0));
// ldr scratch, [scratch, #0]
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLDRi)
.addReg(ScratchReg)
.addReg(ScratchReg)
.addImm(0)
.addImm(ARMCC::AL)
.addReg(0));
// Load expected type inline (instead of EOR sequence)
//
// This creates the 32-bit value byte-by-byte in the temp register:
// movs temp, #byte3 (high byte)
// lsls temp, temp, #8
// adds temp, #byte2
// lsls temp, temp, #8
// adds temp, #byte1
// lsls temp, temp, #8
// adds temp, #byte0 (low byte)
uint8_t byte0 = (Type >> 0) & 0xFF;
uint8_t byte1 = (Type >> 8) & 0xFF;
uint8_t byte2 = (Type >> 16) & 0xFF;
uint8_t byte3 = (Type >> 24) & 0xFF;
// movs temp, #byte3 (start with high byte)
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tMOVi8)
.addReg(TempReg)
.addReg(ARM::CPSR)
.addImm(byte3)
.addImm(ARMCC::AL)
.addReg(0));
// lsls temp, temp, #8
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLSLri)
.addReg(TempReg)
.addReg(ARM::CPSR)
.addReg(TempReg)
.addImm(8)
.addImm(ARMCC::AL)
.addReg(0));
// adds temp, #byte2
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tADDi8)
.addReg(TempReg)
.addReg(ARM::CPSR)
.addReg(TempReg)
.addImm(byte2)
.addImm(ARMCC::AL)
.addReg(0));
// lsls temp, temp, #8
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLSLri)
.addReg(TempReg)
.addReg(ARM::CPSR)
.addReg(TempReg)
.addImm(8)
.addImm(ARMCC::AL)
.addReg(0));
// adds temp, #byte1
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tADDi8)
.addReg(TempReg)
.addReg(ARM::CPSR)
.addReg(TempReg)
.addImm(byte1)
.addImm(ARMCC::AL)
.addReg(0));
// lsls temp, temp, #8
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLSLri)
.addReg(TempReg)
.addReg(ARM::CPSR)
.addReg(TempReg)
.addImm(8)
.addImm(ARMCC::AL)
.addReg(0));
// adds temp, #byte0 (low byte)
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tADDi8)
.addReg(TempReg)
.addReg(ARM::CPSR)
.addReg(TempReg)
.addImm(byte0)
.addImm(ARMCC::AL)
.addReg(0));
// cmp scratch, temp
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tCMPr)
.addReg(ScratchReg)
.addReg(TempReg)
.addImm(ARMCC::AL)
.addReg(0));
// Restore registers if spilled (pop in reverse order of push: R2, then R3)
if (NeedSpillR2) {
// pop {r2}
EmitToStreamer(
*OutStreamer,
MCInstBuilder(ARM::tPOP).addImm(ARMCC::AL).addReg(0).addReg(ARM::R2));
}
// Restore r3 if spilled
if (NeedSpillR3) {
// pop {r3}
EmitToStreamer(
*OutStreamer,
MCInstBuilder(ARM::tPOP).addImm(ARMCC::AL).addReg(0).addReg(ARM::R3));
}
// beq .Lpass (branch if types match, i.e., scratch == temp)
MCSymbol *Pass = OutContext.createTempSymbol();
EmitToStreamer(*OutStreamer,
MCInstBuilder(ARM::tBcc)
.addExpr(MCSymbolRefExpr::create(Pass, OutContext))
.addImm(ARMCC::EQ)
.addReg(ARM::CPSR));
// bkpt #0 (trap with encoded diagnostic)
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tBKPT).addImm(0));
OutStreamer->emitLabel(Pass);
}
void ARMAsmPrinter::LowerKCFI_CHECK(const MachineInstr &MI) {
Register AddrReg = MI.getOperand(0).getReg();
const int64_t Type = MI.getOperand(1).getImm();
// Get the call instruction that follows this KCFI_CHECK.
assert(std::next(MI.getIterator())->isCall() &&
"KCFI_CHECK not followed by a call instruction");
const MachineInstr &Call = *std::next(MI.getIterator());
// Adjust the offset for patchable-function-prefix.
int64_t PrefixNops = MI.getMF()->getFunction().getFnAttributeAsParsedInteger(
"patchable-function-prefix");
// Emit the appropriate instruction sequence based on the opcode variant.
switch (MI.getOpcode()) {
case ARM::KCFI_CHECK_ARM:
EmitKCFI_CHECK_ARM32(AddrReg, Type, Call, PrefixNops);
break;
case ARM::KCFI_CHECK_Thumb2:
EmitKCFI_CHECK_Thumb2(AddrReg, Type, Call, PrefixNops);
break;
case ARM::KCFI_CHECK_Thumb1:
EmitKCFI_CHECK_Thumb1(AddrReg, Type, Call, PrefixNops);
break;
default:
llvm_unreachable("Unexpected KCFI_CHECK opcode");
}
}
void ARMAsmPrinter::emitInstruction(const MachineInstr *MI) {
ARM_MC::verifyInstructionPredicates(MI->getOpcode(),
getSubtargetInfo().getFeatureBits());
const ARMSubtarget &STI = MF->getSubtarget<ARMSubtarget>();
const DataLayout &DL = getDataLayout();
MCTargetStreamer &TS = *OutStreamer->getTargetStreamer();
ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
// If we just ended a constant pool, mark it as such.
if (InConstantPool && MI->getOpcode() != ARM::CONSTPOOL_ENTRY) {
OutStreamer->emitDataRegion(MCDR_DataRegionEnd);
InConstantPool = false;
}
// Emit unwinding stuff for frame-related instructions
if (TM.getTargetTriple().isTargetEHABICompatible() &&
MI->getFlag(MachineInstr::FrameSetup))
EmitUnwindingInstruction(MI);
// Do any auto-generated pseudo lowerings.
if (MCInst OutInst; lowerPseudoInstExpansion(MI, OutInst)) {
EmitToStreamer(*OutStreamer, OutInst);
return;
}
assert(!convertAddSubFlagsOpcode(MI->getOpcode()) &&
"Pseudo flag setting opcode should be expanded early");
// Check for manual lowerings.
unsigned Opc = MI->getOpcode();
switch (Opc) {
case ARM::t2MOVi32imm: llvm_unreachable("Should be lowered by thumb2it pass");
case ARM::DBG_VALUE: llvm_unreachable("Should be handled by generic printing");
case ARM::KCFI_CHECK_ARM:
case ARM::KCFI_CHECK_Thumb2:
case ARM::KCFI_CHECK_Thumb1:
LowerKCFI_CHECK(*MI);
return;
case ARM::LEApcrel:
case ARM::tLEApcrel:
case ARM::t2LEApcrel: {
// FIXME: Need to also handle globals and externals
MCSymbol *CPISymbol = GetCPISymbol(MI->getOperand(1).getIndex());
EmitToStreamer(*OutStreamer, MCInstBuilder(MI->getOpcode() ==
ARM::t2LEApcrel ? ARM::t2ADR
: (MI->getOpcode() == ARM::tLEApcrel ? ARM::tADR
: ARM::ADR))
.addReg(MI->getOperand(0).getReg())
.addExpr(MCSymbolRefExpr::create(CPISymbol, OutContext))
// Add predicate operands.
.addImm(MI->getOperand(2).getImm())
.addReg(MI->getOperand(3).getReg()));
return;
}
case ARM::LEApcrelJT:
case ARM::tLEApcrelJT:
case ARM::t2LEApcrelJT: {
MCSymbol *JTIPICSymbol =
GetARMJTIPICJumpTableLabel(MI->getOperand(1).getIndex());
EmitToStreamer(*OutStreamer, MCInstBuilder(MI->getOpcode() ==
ARM::t2LEApcrelJT ? ARM::t2ADR
: (MI->getOpcode() == ARM::tLEApcrelJT ? ARM::tADR
: ARM::ADR))
.addReg(MI->getOperand(0).getReg())
.addExpr(MCSymbolRefExpr::create(JTIPICSymbol, OutContext))
// Add predicate operands.
.addImm(MI->getOperand(2).getImm())
.addReg(MI->getOperand(3).getReg()));
return;
}
// Darwin call instructions are just normal call instructions with different
// clobber semantics (they clobber R9).
case ARM::BX_CALL: {
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::MOVr)
.addReg(ARM::LR)
.addReg(ARM::PC)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0)
// Add 's' bit operand (always reg0 for this)
.addReg(0));
assert(STI.hasV4TOps() && "Expected V4TOps for BX call");
EmitToStreamer(*OutStreamer,
MCInstBuilder(ARM::BX).addReg(MI->getOperand(0).getReg()));
return;
}
case ARM::tBX_CALL: {
assert(!STI.hasV5TOps() && "Expected BLX to be selected for v5t+");
// On ARM v4t, when doing a call from thumb mode, we need to ensure
// that the saved lr has its LSB set correctly (the arch doesn't
// have blx).
// So here we generate a bl to a small jump pad that does bx rN.
// The jump pads are emitted after the function body.
Register TReg = MI->getOperand(0).getReg();
MCSymbol *TRegSym = nullptr;
for (std::pair<unsigned, MCSymbol *> &TIP : ThumbIndirectPads) {
if (TIP.first == TReg) {
TRegSym = TIP.second;
break;
}
}
if (!TRegSym) {
TRegSym = OutContext.createTempSymbol();
ThumbIndirectPads.push_back(std::make_pair(TReg, TRegSym));
}
// Create a link-saving branch to the Reg Indirect Jump Pad.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tBL)
// Predicate comes first here.
.addImm(ARMCC::AL).addReg(0)
.addExpr(MCSymbolRefExpr::create(TRegSym, OutContext)));
return;
}
case ARM::BMOVPCRX_CALL: {
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::MOVr)
.addReg(ARM::LR)
.addReg(ARM::PC)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0)
// Add 's' bit operand (always reg0 for this)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::MOVr)
.addReg(ARM::PC)
.addReg(MI->getOperand(0).getReg())
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0)
// Add 's' bit operand (always reg0 for this)
.addReg(0));
return;
}
case ARM::BMOVPCB_CALL: {
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::MOVr)
.addReg(ARM::LR)
.addReg(ARM::PC)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0)
// Add 's' bit operand (always reg0 for this)
.addReg(0));
const MachineOperand &Op = MI->getOperand(0);
const GlobalValue *GV = Op.getGlobal();
const unsigned TF = Op.getTargetFlags();
MCSymbol *GVSym = GetARMGVSymbol(GV, TF);
const MCExpr *GVSymExpr = MCSymbolRefExpr::create(GVSym, OutContext);
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::Bcc)
.addExpr(GVSymExpr)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
return;
}
case ARM::MOVi16_ga_pcrel:
case ARM::t2MOVi16_ga_pcrel: {
MCInst TmpInst;
TmpInst.setOpcode(Opc == ARM::MOVi16_ga_pcrel? ARM::MOVi16 : ARM::t2MOVi16);
TmpInst.addOperand(MCOperand::createReg(MI->getOperand(0).getReg()));
unsigned TF = MI->getOperand(1).getTargetFlags();
const GlobalValue *GV = MI->getOperand(1).getGlobal();
MCSymbol *GVSym = GetARMGVSymbol(GV, TF);
const MCExpr *GVSymExpr = MCSymbolRefExpr::create(GVSym, OutContext);
MCSymbol *LabelSym =
getPICLabel(DL.getInternalSymbolPrefix(), getFunctionNumber(),
MI->getOperand(2).getImm(), OutContext);
const MCExpr *LabelSymExpr= MCSymbolRefExpr::create(LabelSym, OutContext);
unsigned PCAdj = (Opc == ARM::MOVi16_ga_pcrel) ? 8 : 4;
const MCExpr *PCRelExpr = ARM::createLower16(
MCBinaryExpr::createSub(
GVSymExpr,
MCBinaryExpr::createAdd(LabelSymExpr,
MCConstantExpr::create(PCAdj, OutContext),
OutContext),
OutContext),
OutContext);
TmpInst.addOperand(MCOperand::createExpr(PCRelExpr));
// Add predicate operands.
TmpInst.addOperand(MCOperand::createImm(ARMCC::AL));
TmpInst.addOperand(MCOperand::createReg(0));
// Add 's' bit operand (always reg0 for this)
TmpInst.addOperand(MCOperand::createReg(0));
EmitToStreamer(*OutStreamer, TmpInst);
return;
}
case ARM::MOVTi16_ga_pcrel:
case ARM::t2MOVTi16_ga_pcrel: {
MCInst TmpInst;
TmpInst.setOpcode(Opc == ARM::MOVTi16_ga_pcrel
? ARM::MOVTi16 : ARM::t2MOVTi16);
TmpInst.addOperand(MCOperand::createReg(MI->getOperand(0).getReg()));
TmpInst.addOperand(MCOperand::createReg(MI->getOperand(1).getReg()));
unsigned TF = MI->getOperand(2).getTargetFlags();
const GlobalValue *GV = MI->getOperand(2).getGlobal();
MCSymbol *GVSym = GetARMGVSymbol(GV, TF);
const MCExpr *GVSymExpr = MCSymbolRefExpr::create(GVSym, OutContext);
MCSymbol *LabelSym =
getPICLabel(DL.getInternalSymbolPrefix(), getFunctionNumber(),
MI->getOperand(3).getImm(), OutContext);
const MCExpr *LabelSymExpr= MCSymbolRefExpr::create(LabelSym, OutContext);
unsigned PCAdj = (Opc == ARM::MOVTi16_ga_pcrel) ? 8 : 4;
const MCExpr *PCRelExpr = ARM::createUpper16(
MCBinaryExpr::createSub(
GVSymExpr,
MCBinaryExpr::createAdd(LabelSymExpr,
MCConstantExpr::create(PCAdj, OutContext),
OutContext),
OutContext),
OutContext);
TmpInst.addOperand(MCOperand::createExpr(PCRelExpr));
// Add predicate operands.
TmpInst.addOperand(MCOperand::createImm(ARMCC::AL));
TmpInst.addOperand(MCOperand::createReg(0));
// Add 's' bit operand (always reg0 for this)
TmpInst.addOperand(MCOperand::createReg(0));
EmitToStreamer(*OutStreamer, TmpInst);
return;
}
case ARM::t2BFi:
case ARM::t2BFic:
case ARM::t2BFLi:
case ARM::t2BFr:
case ARM::t2BFLr: {
// This is a Branch Future instruction.
const MCExpr *BranchLabel = MCSymbolRefExpr::create(
getBFLabel(DL.getInternalSymbolPrefix(), getFunctionNumber(),
MI->getOperand(0).getIndex(), OutContext),
OutContext);
auto MCInst = MCInstBuilder(Opc).addExpr(BranchLabel);
if (MI->getOperand(1).isReg()) {
// For BFr/BFLr
MCInst.addReg(MI->getOperand(1).getReg());
} else {
// For BFi/BFLi/BFic
const MCExpr *BranchTarget;
if (MI->getOperand(1).isMBB())
BranchTarget = MCSymbolRefExpr::create(
MI->getOperand(1).getMBB()->getSymbol(), OutContext);
else if (MI->getOperand(1).isGlobal()) {
const GlobalValue *GV = MI->getOperand(1).getGlobal();
BranchTarget = MCSymbolRefExpr::create(
GetARMGVSymbol(GV, MI->getOperand(1).getTargetFlags()), OutContext);
} else if (MI->getOperand(1).isSymbol()) {
BranchTarget = MCSymbolRefExpr::create(
GetExternalSymbolSymbol(MI->getOperand(1).getSymbolName()),
OutContext);
} else
llvm_unreachable("Unhandled operand kind in Branch Future instruction");
MCInst.addExpr(BranchTarget);
}
if (Opc == ARM::t2BFic) {
const MCExpr *ElseLabel = MCSymbolRefExpr::create(
getBFLabel(DL.getInternalSymbolPrefix(), getFunctionNumber(),
MI->getOperand(2).getIndex(), OutContext),
OutContext);
MCInst.addExpr(ElseLabel);
MCInst.addImm(MI->getOperand(3).getImm());
} else {
MCInst.addImm(MI->getOperand(2).getImm())
.addReg(MI->getOperand(3).getReg());
}
EmitToStreamer(*OutStreamer, MCInst);
return;
}
case ARM::t2BF_LabelPseudo: {
// This is a pseudo op for a label used by a branch future instruction
// Emit the label.
OutStreamer->emitLabel(
getBFLabel(DL.getInternalSymbolPrefix(), getFunctionNumber(),
MI->getOperand(0).getIndex(), OutContext));
return;
}
case ARM::tPICADD: {
// This is a pseudo op for a label + instruction sequence, which looks like:
// LPC0:
// add r0, pc
// This adds the address of LPC0 to r0.
// Emit the label.
OutStreamer->emitLabel(getPICLabel(DL.getInternalSymbolPrefix(),
getFunctionNumber(),
MI->getOperand(2).getImm(), OutContext));
// Form and emit the add.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tADDhirr)
.addReg(MI->getOperand(0).getReg())
.addReg(MI->getOperand(0).getReg())
.addReg(ARM::PC)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
return;
}
case ARM::PICADD: {
// This is a pseudo op for a label + instruction sequence, which looks like:
// LPC0:
// add r0, pc, r0
// This adds the address of LPC0 to r0.
// Emit the label.
OutStreamer->emitLabel(getPICLabel(DL.getInternalSymbolPrefix(),
getFunctionNumber(),
MI->getOperand(2).getImm(), OutContext));
// Form and emit the add.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::ADDrr)
.addReg(MI->getOperand(0).getReg())
.addReg(ARM::PC)
.addReg(MI->getOperand(1).getReg())
// Add predicate operands.
.addImm(MI->getOperand(3).getImm())
.addReg(MI->getOperand(4).getReg())
// Add 's' bit operand (always reg0 for this)
.addReg(0));
return;
}
case ARM::PICSTR:
case ARM::PICSTRB:
case ARM::PICSTRH:
case ARM::PICLDR:
case ARM::PICLDRB:
case ARM::PICLDRH:
case ARM::PICLDRSB:
case ARM::PICLDRSH: {
// This is a pseudo op for a label + instruction sequence, which looks like:
// LPC0:
// OP r0, [pc, r0]
// The LCP0 label is referenced by a constant pool entry in order to get
// a PC-relative address at the ldr instruction.
// Emit the label.
OutStreamer->emitLabel(getPICLabel(DL.getInternalSymbolPrefix(),
getFunctionNumber(),
MI->getOperand(2).getImm(), OutContext));
// Form and emit the load
unsigned Opcode;
switch (MI->getOpcode()) {
default:
llvm_unreachable("Unexpected opcode!");
case ARM::PICSTR: Opcode = ARM::STRrs; break;
case ARM::PICSTRB: Opcode = ARM::STRBrs; break;
case ARM::PICSTRH: Opcode = ARM::STRH; break;
case ARM::PICLDR: Opcode = ARM::LDRrs; break;
case ARM::PICLDRB: Opcode = ARM::LDRBrs; break;
case ARM::PICLDRH: Opcode = ARM::LDRH; break;
case ARM::PICLDRSB: Opcode = ARM::LDRSB; break;
case ARM::PICLDRSH: Opcode = ARM::LDRSH; break;
}
EmitToStreamer(*OutStreamer, MCInstBuilder(Opcode)
.addReg(MI->getOperand(0).getReg())
.addReg(ARM::PC)
.addReg(MI->getOperand(1).getReg())
.addImm(0)
// Add predicate operands.
.addImm(MI->getOperand(3).getImm())
.addReg(MI->getOperand(4).getReg()));
return;
}
case ARM::CONSTPOOL_ENTRY: {
assert(!STI.genExecuteOnly() &&
"execute-only should not generate constant pools");
/// CONSTPOOL_ENTRY - This instruction represents a floating constant pool
/// in the function. The first operand is the ID# for this instruction, the
/// second is the index into the MachineConstantPool that this is, the third
/// is the size in bytes of this constant pool entry.
/// The required alignment is specified on the basic block holding this MI.
unsigned LabelId = (unsigned)MI->getOperand(0).getImm();
unsigned CPIdx = (unsigned)MI->getOperand(1).getIndex();
// If this is the first entry of the pool, mark it.
if (!InConstantPool) {
OutStreamer->emitDataRegion(MCDR_DataRegion);
InConstantPool = true;
}
OutStreamer->emitLabel(GetCPISymbol(LabelId));
const MachineConstantPoolEntry &MCPE = MCP->getConstants()[CPIdx];
if (MCPE.isMachineConstantPoolEntry())
emitMachineConstantPoolValue(MCPE.Val.MachineCPVal);
else
emitGlobalConstant(DL, MCPE.Val.ConstVal);
return;
}
case ARM::JUMPTABLE_ADDRS:
emitJumpTableAddrs(MI);
return;
case ARM::JUMPTABLE_INSTS:
emitJumpTableInsts(MI);
return;
case ARM::JUMPTABLE_TBB:
case ARM::JUMPTABLE_TBH:
emitJumpTableTBInst(MI, MI->getOpcode() == ARM::JUMPTABLE_TBB ? 1 : 2);
return;
case ARM::t2BR_JT: {
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tMOVr)
.addReg(ARM::PC)
.addReg(MI->getOperand(0).getReg())
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
return;
}
case ARM::t2TBB_JT:
case ARM::t2TBH_JT: {
unsigned Opc = MI->getOpcode() == ARM::t2TBB_JT ? ARM::t2TBB : ARM::t2TBH;
// Lower and emit the PC label, then the instruction itself.
OutStreamer->emitLabel(GetCPISymbol(MI->getOperand(3).getImm()));
EmitToStreamer(*OutStreamer, MCInstBuilder(Opc)
.addReg(MI->getOperand(0).getReg())
.addReg(MI->getOperand(1).getReg())
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
return;
}
case ARM::tTBB_JT:
case ARM::tTBH_JT: {
bool Is8Bit = MI->getOpcode() == ARM::tTBB_JT;
Register Base = MI->getOperand(0).getReg();
Register Idx = MI->getOperand(1).getReg();
assert(MI->getOperand(1).isKill() && "We need the index register as scratch!");
// Multiply up idx if necessary.
if (!Is8Bit)
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLSLri)
.addReg(Idx)
.addReg(ARM::CPSR)
.addReg(Idx)
.addImm(1)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
if (Base == ARM::PC) {
// TBB [base, idx] =
// ADDS idx, idx, base
// LDRB idx, [idx, #4] ; or LDRH if TBH
// LSLS idx, #1
// ADDS pc, pc, idx
// When using PC as the base, it's important that there is no padding
// between the last ADDS and the start of the jump table. The jump table
// is 4-byte aligned, so we ensure we're 4 byte aligned here too.
//
// FIXME: Ideally we could vary the LDRB index based on the padding
// between the sequence and jump table, however that relies on MCExprs
// for load indexes which are currently not supported.
OutStreamer->emitCodeAlignment(Align(4), getSubtargetInfo());
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tADDhirr)
.addReg(Idx)
.addReg(Idx)
.addReg(Base)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
unsigned Opc = Is8Bit ? ARM::tLDRBi : ARM::tLDRHi;
EmitToStreamer(*OutStreamer, MCInstBuilder(Opc)
.addReg(Idx)
.addReg(Idx)
.addImm(Is8Bit ? 4 : 2)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
} else {
// TBB [base, idx] =
// LDRB idx, [base, idx] ; or LDRH if TBH
// LSLS idx, #1
// ADDS pc, pc, idx
unsigned Opc = Is8Bit ? ARM::tLDRBr : ARM::tLDRHr;
EmitToStreamer(*OutStreamer, MCInstBuilder(Opc)
.addReg(Idx)
.addReg(Base)
.addReg(Idx)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
}
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLSLri)
.addReg(Idx)
.addReg(ARM::CPSR)
.addReg(Idx)
.addImm(1)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
OutStreamer->emitLabel(GetCPISymbol(MI->getOperand(3).getImm()));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tADDhirr)
.addReg(ARM::PC)
.addReg(ARM::PC)
.addReg(Idx)
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0));
return;
}
case ARM::tBR_JTr:
case ARM::BR_JTr: {
// mov pc, target
MCInst TmpInst;
unsigned Opc = MI->getOpcode() == ARM::BR_JTr ?
ARM::MOVr : ARM::tMOVr;
TmpInst.setOpcode(Opc);
TmpInst.addOperand(MCOperand::createReg(ARM::PC));
TmpInst.addOperand(MCOperand::createReg(MI->getOperand(0).getReg()));
// Add predicate operands.
TmpInst.addOperand(MCOperand::createImm(ARMCC::AL));
TmpInst.addOperand(MCOperand::createReg(0));
// Add 's' bit operand (always reg0 for this)
if (Opc == ARM::MOVr)
TmpInst.addOperand(MCOperand::createReg(0));
EmitToStreamer(*OutStreamer, TmpInst);
return;
}
case ARM::BR_JTm_i12: {
// ldr pc, target
MCInst TmpInst;
TmpInst.setOpcode(ARM::LDRi12);
TmpInst.addOperand(MCOperand::createReg(ARM::PC));
TmpInst.addOperand(MCOperand::createReg(MI->getOperand(0).getReg()));
TmpInst.addOperand(MCOperand::createImm(MI->getOperand(2).getImm()));
// Add predicate operands.
TmpInst.addOperand(MCOperand::createImm(ARMCC::AL));
TmpInst.addOperand(MCOperand::createReg(0));
EmitToStreamer(*OutStreamer, TmpInst);
return;
}
case ARM::BR_JTm_rs: {
// ldr pc, target
MCInst TmpInst;
TmpInst.setOpcode(ARM::LDRrs);
TmpInst.addOperand(MCOperand::createReg(ARM::PC));
TmpInst.addOperand(MCOperand::createReg(MI->getOperand(0).getReg()));
TmpInst.addOperand(MCOperand::createReg(MI->getOperand(1).getReg()));
TmpInst.addOperand(MCOperand::createImm(MI->getOperand(2).getImm()));
// Add predicate operands.
TmpInst.addOperand(MCOperand::createImm(ARMCC::AL));
TmpInst.addOperand(MCOperand::createReg(0));
EmitToStreamer(*OutStreamer, TmpInst);
return;
}
case ARM::BR_JTadd: {
// add pc, target, idx
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::ADDrr)
.addReg(ARM::PC)
.addReg(MI->getOperand(0).getReg())
.addReg(MI->getOperand(1).getReg())
// Add predicate operands.
.addImm(ARMCC::AL)
.addReg(0)
// Add 's' bit operand (always reg0 for this)
.addReg(0));
return;
}
case ARM::SPACE:
OutStreamer->emitZeros(MI->getOperand(1).getImm());
return;
case ARM::TRAP: {
// Non-Darwin binutils don't yet support the "trap" mnemonic.
// FIXME: Remove this special case when they do.
if (!TM.getTargetTriple().isOSBinFormatMachO()) {
uint32_t Val = 0xe7ffdefeUL;
OutStreamer->AddComment("trap");
ATS.emitInst(Val);
return;
}
break;
}
case ARM::tTRAP: {
// Non-Darwin binutils don't yet support the "trap" mnemonic.
// FIXME: Remove this special case when they do.
if (!TM.getTargetTriple().isOSBinFormatMachO()) {
uint16_t Val = 0xdefe;
OutStreamer->AddComment("trap");
ATS.emitInst(Val, 'n');
return;
}
break;
}
case ARM::t2Int_eh_sjlj_setjmp:
case ARM::t2Int_eh_sjlj_setjmp_nofp:
case ARM::tInt_eh_sjlj_setjmp: {
// Two incoming args: GPR:$src, GPR:$val
// mov $val, pc
// adds $val, #7
// str $val, [$src, #4]
// movs r0, #0
// b LSJLJEH
// movs r0, #1
// LSJLJEH:
Register SrcReg = MI->getOperand(0).getReg();
Register ValReg = MI->getOperand(1).getReg();
MCSymbol *Label = OutContext.createTempSymbol("SJLJEH");
OutStreamer->AddComment("eh_setjmp begin");
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tMOVr)
.addReg(ValReg)
.addReg(ARM::PC)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tADDi3)
.addReg(ValReg)
// 's' bit operand
.addReg(ARM::CPSR)
.addReg(ValReg)
.addImm(7)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tSTRi)
.addReg(ValReg)
.addReg(SrcReg)
// The offset immediate is #4. The operand value is scaled by 4 for the
// tSTR instruction.
.addImm(1)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tMOVi8)
.addReg(ARM::R0)
.addReg(ARM::CPSR)
.addImm(0)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
const MCExpr *SymbolExpr = MCSymbolRefExpr::create(Label, OutContext);
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tB)
.addExpr(SymbolExpr)
.addImm(ARMCC::AL)
.addReg(0));
OutStreamer->AddComment("eh_setjmp end");
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tMOVi8)
.addReg(ARM::R0)
.addReg(ARM::CPSR)
.addImm(1)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
OutStreamer->emitLabel(Label);
return;
}
case ARM::Int_eh_sjlj_setjmp_nofp:
case ARM::Int_eh_sjlj_setjmp: {
// Two incoming args: GPR:$src, GPR:$val
// add $val, pc, #8
// str $val, [$src, #+4]
// mov r0, #0
// add pc, pc, #0
// mov r0, #1
Register SrcReg = MI->getOperand(0).getReg();
Register ValReg = MI->getOperand(1).getReg();
OutStreamer->AddComment("eh_setjmp begin");
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::ADDri)
.addReg(ValReg)
.addReg(ARM::PC)
.addImm(8)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0)
// 's' bit operand (always reg0 for this).
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::STRi12)
.addReg(ValReg)
.addReg(SrcReg)
.addImm(4)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::MOVi)
.addReg(ARM::R0)
.addImm(0)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0)
// 's' bit operand (always reg0 for this).
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::ADDri)
.addReg(ARM::PC)
.addReg(ARM::PC)
.addImm(0)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0)
// 's' bit operand (always reg0 for this).
.addReg(0));
OutStreamer->AddComment("eh_setjmp end");
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::MOVi)
.addReg(ARM::R0)
.addImm(1)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0)
// 's' bit operand (always reg0 for this).
.addReg(0));
return;
}
case ARM::Int_eh_sjlj_longjmp: {
// ldr sp, [$src, #8]
// ldr $scratch, [$src, #4]
// ldr r7, [$src]
// bx $scratch
Register SrcReg = MI->getOperand(0).getReg();
Register ScratchReg = MI->getOperand(1).getReg();
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::LDRi12)
.addReg(ARM::SP)
.addReg(SrcReg)
.addImm(8)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::LDRi12)
.addReg(ScratchReg)
.addReg(SrcReg)
.addImm(4)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
if (STI.isTargetDarwin() || STI.isTargetWindows()) {
// These platforms always use the same frame register
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::LDRi12)
.addReg(STI.getFramePointerReg())
.addReg(SrcReg)
.addImm(0)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
} else {
// If the calling code might use either R7 or R11 as
// frame pointer register, restore it into both.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::LDRi12)
.addReg(ARM::R7)
.addReg(SrcReg)
.addImm(0)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::LDRi12)
.addReg(ARM::R11)
.addReg(SrcReg)
.addImm(0)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
}
assert(STI.hasV4TOps());
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::BX)
.addReg(ScratchReg)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
return;
}
case ARM::tInt_eh_sjlj_longjmp: {
// ldr $scratch, [$src, #8]
// mov sp, $scratch
// ldr $scratch, [$src, #4]
// ldr r7, [$src]
// bx $scratch
Register SrcReg = MI->getOperand(0).getReg();
Register ScratchReg = MI->getOperand(1).getReg();
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLDRi)
.addReg(ScratchReg)
.addReg(SrcReg)
// The offset immediate is #8. The operand value is scaled by 4 for the
// tLDR instruction.
.addImm(2)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tMOVr)
.addReg(ARM::SP)
.addReg(ScratchReg)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLDRi)
.addReg(ScratchReg)
.addReg(SrcReg)
.addImm(1)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
if (STI.isTargetDarwin() || STI.isTargetWindows()) {
// These platforms always use the same frame register
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLDRi)
.addReg(STI.getFramePointerReg())
.addReg(SrcReg)
.addImm(0)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
} else {
// If the calling code might use either R7 or R11 as
// frame pointer register, restore it into both.
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLDRi)
.addReg(ARM::R7)
.addReg(SrcReg)
.addImm(0)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tLDRi)
.addReg(ARM::R11)
.addReg(SrcReg)
.addImm(0)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
}
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::tBX)
.addReg(ScratchReg)
// Predicate.
.addImm(ARMCC::AL)
.addReg(0));
return;
}
case ARM::tInt_WIN_eh_sjlj_longjmp: {
// ldr.w r11, [$src, #0]
// ldr.w sp, [$src, #8]
// ldr.w pc, [$src, #4]
Register SrcReg = MI->getOperand(0).getReg();
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2LDRi12)
.addReg(ARM::R11)
.addReg(SrcReg)
.addImm(0)
// Predicate
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2LDRi12)
.addReg(ARM::SP)
.addReg(SrcReg)
.addImm(8)
// Predicate
.addImm(ARMCC::AL)
.addReg(0));
EmitToStreamer(*OutStreamer, MCInstBuilder(ARM::t2LDRi12)
.addReg(ARM::PC)
.addReg(SrcReg)
.addImm(4)
// Predicate
.addImm(ARMCC::AL)
.addReg(0));
return;
}
case ARM::PATCHABLE_FUNCTION_ENTER:
LowerPATCHABLE_FUNCTION_ENTER(*MI);
return;
case ARM::PATCHABLE_FUNCTION_EXIT:
LowerPATCHABLE_FUNCTION_EXIT(*MI);
return;
case ARM::PATCHABLE_TAIL_CALL:
LowerPATCHABLE_TAIL_CALL(*MI);
return;
case ARM::SpeculationBarrierISBDSBEndBB: {
// Print DSB SYS + ISB
MCInst TmpInstDSB;
TmpInstDSB.setOpcode(ARM::DSB);
TmpInstDSB.addOperand(MCOperand::createImm(0xf));
EmitToStreamer(*OutStreamer, TmpInstDSB);
MCInst TmpInstISB;
TmpInstISB.setOpcode(ARM::ISB);
TmpInstISB.addOperand(MCOperand::createImm(0xf));
EmitToStreamer(*OutStreamer, TmpInstISB);
return;
}
case ARM::t2SpeculationBarrierISBDSBEndBB: {
// Print DSB SYS + ISB
MCInst TmpInstDSB;
TmpInstDSB.setOpcode(ARM::t2DSB);
TmpInstDSB.addOperand(MCOperand::createImm(0xf));
TmpInstDSB.addOperand(MCOperand::createImm(ARMCC::AL));
TmpInstDSB.addOperand(MCOperand::createReg(0));
EmitToStreamer(*OutStreamer, TmpInstDSB);
MCInst TmpInstISB;
TmpInstISB.setOpcode(ARM::t2ISB);
TmpInstISB.addOperand(MCOperand::createImm(0xf));
TmpInstISB.addOperand(MCOperand::createImm(ARMCC::AL));
TmpInstISB.addOperand(MCOperand::createReg(0));
EmitToStreamer(*OutStreamer, TmpInstISB);
return;
}
case ARM::SpeculationBarrierSBEndBB: {
// Print SB
MCInst TmpInstSB;
TmpInstSB.setOpcode(ARM::SB);
EmitToStreamer(*OutStreamer, TmpInstSB);
return;
}
case ARM::t2SpeculationBarrierSBEndBB: {
// Print SB
MCInst TmpInstSB;
TmpInstSB.setOpcode(ARM::t2SB);
EmitToStreamer(*OutStreamer, TmpInstSB);
return;
}
case ARM::SEH_StackAlloc:
ATS.emitARMWinCFIAllocStack(MI->getOperand(0).getImm(),
MI->getOperand(1).getImm());
return;
case ARM::SEH_SaveRegs:
case ARM::SEH_SaveRegs_Ret:
ATS.emitARMWinCFISaveRegMask(MI->getOperand(0).getImm(),
MI->getOperand(1).getImm());
return;
case ARM::SEH_SaveSP:
ATS.emitARMWinCFISaveSP(MI->getOperand(0).getImm());
return;
case ARM::SEH_SaveFRegs:
ATS.emitARMWinCFISaveFRegs(MI->getOperand(0).getImm(),
MI->getOperand(1).getImm());
return;
case ARM::SEH_SaveLR:
ATS.emitARMWinCFISaveLR(MI->getOperand(0).getImm());
return;
case ARM::SEH_Nop:
case ARM::SEH_Nop_Ret:
ATS.emitARMWinCFINop(MI->getOperand(0).getImm());
return;
case ARM::SEH_PrologEnd:
ATS.emitARMWinCFIPrologEnd(/*Fragment=*/false);
return;
case ARM::SEH_EpilogStart:
ATS.emitARMWinCFIEpilogStart(ARMCC::AL);
return;
case ARM::SEH_EpilogEnd:
ATS.emitARMWinCFIEpilogEnd();
return;
}
MCInst TmpInst;
LowerARMMachineInstrToMCInst(MI, TmpInst, *this);
EmitToStreamer(*OutStreamer, TmpInst);
}
char ARMAsmPrinter::ID = 0;
INITIALIZE_PASS(ARMAsmPrinter, "arm-asm-printer", "ARM Assembly Printer", false,
false)
//===----------------------------------------------------------------------===//
// Target Registry Stuff
//===----------------------------------------------------------------------===//
// Force static initialization.
extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
LLVMInitializeARMAsmPrinter() {
RegisterAsmPrinter<ARMAsmPrinter> X(getTheARMLETarget());
RegisterAsmPrinter<ARMAsmPrinter> Y(getTheARMBETarget());
RegisterAsmPrinter<ARMAsmPrinter> A(getTheThumbLETarget());
RegisterAsmPrinter<ARMAsmPrinter> B(getTheThumbBETarget());
}