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llvm-project/llvm/lib/Target/X86/X86ATTAsmPrinter.cpp

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//===-- X86ATTAsmPrinter.cpp - Convert X86 LLVM code to AT&T assembly -----===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains a printer that converts from our internal representation
// of machine-dependent LLVM code to AT&T format assembly
// language. This printer is the output mechanism used by `llc'.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "asm-printer"
#include "X86ATTAsmPrinter.h"
#include "X86.h"
#include "X86COFF.h"
#include "X86MachineFunctionInfo.h"
#include "X86TargetMachine.h"
#include "X86TargetAsmInfo.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/CallingConv.h"
#include "llvm/Module.h"
#include "llvm/Support/Mangler.h"
#include "llvm/Target/TargetAsmInfo.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/Statistic.h"
using namespace llvm;
STATISTIC(EmittedInsts, "Number of machine instrs printed");
static std::string computePICLabel(unsigned FnNum,
const TargetAsmInfo *TAI,
const X86Subtarget* Subtarget) {
std::string label;
if (Subtarget->isTargetDarwin())
label = "\"L" + utostr_32(FnNum) + "$pb\"";
else if (Subtarget->isTargetELF())
label = ".Lllvm$" + utostr_32(FnNum) + "$piclabel";
else
assert(0 && "Don't know how to print PIC label!\n");
return label;
}
/// getSectionForFunction - Return the section that we should emit the
/// specified function body into.
std::string X86ATTAsmPrinter::getSectionForFunction(const Function &F) const {
switch (F.getLinkage()) {
default: assert(0 && "Unknown linkage type!");
case Function::InternalLinkage:
case Function::DLLExportLinkage:
case Function::ExternalLinkage:
return TAI->getTextSection();
case Function::WeakLinkage:
case Function::LinkOnceLinkage:
if (Subtarget->isTargetDarwin()) {
return ".section __TEXT,__textcoal_nt,coalesced,pure_instructions";
} else if (Subtarget->isTargetCygMing()) {
return "\t.section\t.text$linkonce." + CurrentFnName + ",\"ax\"";
} else {
return "\t.section\t.llvm.linkonce.t." + CurrentFnName +
",\"ax\",@progbits";
}
}
}
/// runOnMachineFunction - This uses the printMachineInstruction()
/// method to print assembly for each instruction.
///
bool X86ATTAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
if (TAI->doesSupportDebugInformation()) {
// Let PassManager know we need debug information and relay
// the MachineModuleInfo address on to DwarfWriter.
DW.SetModuleInfo(&getAnalysis<MachineModuleInfo>());
}
SetupMachineFunction(MF);
O << "\n\n";
// Print out constants referenced by the function
EmitConstantPool(MF.getConstantPool());
// Print out labels for the function.
const Function *F = MF.getFunction();
unsigned CC = F->getCallingConv();
// Populate function information map. Actually, We don't want to populate
// non-stdcall or non-fastcall functions' information right now.
if (CC == CallingConv::X86_StdCall || CC == CallingConv::X86_FastCall)
FunctionInfoMap[F] = *MF.getInfo<X86MachineFunctionInfo>();
X86SharedAsmPrinter::decorateName(CurrentFnName, F);
SwitchToTextSection(getSectionForFunction(*F).c_str(), F);
switch (F->getLinkage()) {
default: assert(0 && "Unknown linkage type!");
case Function::InternalLinkage: // Symbols default to internal.
EmitAlignment(4, F); // FIXME: This should be parameterized somewhere.
break;
case Function::DLLExportLinkage:
DLLExportedFns.insert(Mang->makeNameProper(F->getName(), ""));
//FALLS THROUGH
case Function::ExternalLinkage:
EmitAlignment(4, F); // FIXME: This should be parameterized somewhere.
O << "\t.globl\t" << CurrentFnName << "\n";
break;
case Function::LinkOnceLinkage:
case Function::WeakLinkage:
if (Subtarget->isTargetDarwin()) {
O << "\t.globl\t" << CurrentFnName << "\n";
O << "\t.weak_definition\t" << CurrentFnName << "\n";
} else if (Subtarget->isTargetCygMing()) {
EmitAlignment(4, F); // FIXME: This should be parameterized somewhere.
O << "\t.globl " << CurrentFnName << "\n";
O << "\t.linkonce discard\n";
} else {
EmitAlignment(4, F); // FIXME: This should be parameterized somewhere.
O << "\t.weak " << CurrentFnName << "\n";
}
break;
}
if (F->hasHiddenVisibility()) {
if (const char *Directive = TAI->getHiddenDirective())
O << Directive << CurrentFnName << "\n";
} else if (F->hasProtectedVisibility()) {
if (const char *Directive = TAI->getProtectedDirective())
O << Directive << CurrentFnName << "\n";
}
if (Subtarget->isTargetELF())
O << "\t.type " << CurrentFnName << ",@function\n";
else if (Subtarget->isTargetCygMing()) {
O << "\t.def\t " << CurrentFnName
<< ";\t.scl\t" <<
(F->getLinkage() == Function::InternalLinkage ? COFF::C_STAT : COFF::C_EXT)
<< ";\t.type\t" << (COFF::DT_FCN << COFF::N_BTSHFT)
<< ";\t.endef\n";
}
O << CurrentFnName << ":\n";
// Add some workaround for linkonce linkage on Cygwin\MinGW
if (Subtarget->isTargetCygMing() &&
(F->getLinkage() == Function::LinkOnceLinkage ||
F->getLinkage() == Function::WeakLinkage))
O << "Lllvm$workaround$fake$stub$" << CurrentFnName << ":\n";
if (TAI->doesSupportDebugInformation()) {
// Emit pre-function debug information.
DW.BeginFunction(&MF);
}
// Print out code for the function.
for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
I != E; ++I) {
// Print a label for the basic block.
if (I->pred_begin() != I->pred_end()) {
printBasicBlockLabel(I, true);
O << '\n';
}
for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
II != E; ++II) {
// Print the assembly for the instruction.
O << "\t";
printMachineInstruction(II);
}
}
if (TAI->hasDotTypeDotSizeDirective())
O << "\t.size " << CurrentFnName << ", .-" << CurrentFnName << "\n";
if (TAI->doesSupportDebugInformation()) {
// Emit post-function debug information.
DW.EndFunction();
}
// Print out jump tables referenced by the function.
EmitJumpTableInfo(MF.getJumpTableInfo(), MF);
// We didn't modify anything.
return false;
}
static inline bool printGOT(TargetMachine &TM, const X86Subtarget* ST) {
return ST->isPICStyleGOT() && TM.getRelocationModel() == Reloc::PIC_;
}
static inline bool printStub(TargetMachine &TM, const X86Subtarget* ST) {
return ST->isPICStyleStub() && TM.getRelocationModel() != Reloc::Static;
}
void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
const char *Modifier, bool NotRIPRel) {
const MachineOperand &MO = MI->getOperand(OpNo);
const MRegisterInfo &RI = *TM.getRegisterInfo();
switch (MO.getType()) {
case MachineOperand::MO_Register: {
assert(MRegisterInfo::isPhysicalRegister(MO.getReg()) &&
"Virtual registers should not make it this far!");
O << '%';
unsigned Reg = MO.getReg();
if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
MVT::ValueType VT = (strcmp(Modifier+6,"64") == 0) ?
MVT::i64 : ((strcmp(Modifier+6, "32") == 0) ? MVT::i32 :
((strcmp(Modifier+6,"16") == 0) ? MVT::i16 : MVT::i8));
Reg = getX86SubSuperRegister(Reg, VT);
}
for (const char *Name = RI.get(Reg).Name; *Name; ++Name)
O << (char)tolower(*Name);
return;
}
case MachineOperand::MO_Immediate:
if (!Modifier ||
(strcmp(Modifier, "debug") && strcmp(Modifier, "mem")))
O << '$';
O << MO.getImmedValue();
return;
case MachineOperand::MO_MachineBasicBlock:
printBasicBlockLabel(MO.getMachineBasicBlock());
return;
case MachineOperand::MO_JumpTableIndex: {
bool isMemOp = Modifier && !strcmp(Modifier, "mem");
if (!isMemOp) O << '$';
O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber() << "_"
<< MO.getJumpTableIndex();
if (TM.getRelocationModel() == Reloc::PIC_) {
if (Subtarget->isPICStyleStub())
O << "-\"" << TAI->getPrivateGlobalPrefix() << getFunctionNumber()
<< "$pb\"";
else if (Subtarget->isPICStyleGOT())
O << "@GOTOFF";
}
if (isMemOp && Subtarget->isPICStyleRIPRel() && !NotRIPRel)
O << "(%rip)";
return;
}
case MachineOperand::MO_ConstantPoolIndex: {
bool isMemOp = Modifier && !strcmp(Modifier, "mem");
if (!isMemOp) O << '$';
O << TAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << "_"
<< MO.getConstantPoolIndex();
if (TM.getRelocationModel() == Reloc::PIC_) {
if (Subtarget->isPICStyleStub())
O << "-\"" << TAI->getPrivateGlobalPrefix() << getFunctionNumber()
<< "$pb\"";
else if (Subtarget->isPICStyleGOT())
O << "@GOTOFF";
}
int Offset = MO.getOffset();
if (Offset > 0)
O << "+" << Offset;
else if (Offset < 0)
O << Offset;
if (isMemOp && Subtarget->isPICStyleRIPRel() && !NotRIPRel)
O << "(%rip)";
return;
}
case MachineOperand::MO_GlobalAddress: {
bool isCallOp = Modifier && !strcmp(Modifier, "call");
bool isMemOp = Modifier && !strcmp(Modifier, "mem");
bool needCloseParen = false;
GlobalValue *GV = MO.getGlobal();
GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
bool isThreadLocal = GVar && GVar->isThreadLocal();
std::string Name = Mang->getValueName(GV);
X86SharedAsmPrinter::decorateName(Name, GV);
if (!isMemOp && !isCallOp)
O << '$';
else if (Name[0] == '$') {
// The name begins with a dollar-sign. In order to avoid having it look
// like an integer immediate to the assembler, enclose it in parens.
O << '(';
needCloseParen = true;
}
if (printStub(TM, Subtarget)) {
// Link-once, declaration, or Weakly-linked global variables need
// non-lazily-resolved stubs
if (GV->isDeclaration() ||
GV->hasWeakLinkage() ||
GV->hasLinkOnceLinkage()) {
// Dynamically-resolved functions need a stub for the function.
if (isCallOp && isa<Function>(GV)) {
FnStubs.insert(Name);
O << TAI->getPrivateGlobalPrefix() << Name << "$stub";
} else {
GVStubs.insert(Name);
O << TAI->getPrivateGlobalPrefix() << Name << "$non_lazy_ptr";
}
} else {
if (GV->hasDLLImportLinkage())
O << "__imp_";
O << Name;
}
if (!isCallOp && TM.getRelocationModel() == Reloc::PIC_)
O << "-\"" << TAI->getPrivateGlobalPrefix() << getFunctionNumber()
<< "$pb\"";
} else {
if (GV->hasDLLImportLinkage()) {
O << "__imp_";
}
O << Name;
if (isCallOp && isa<Function>(GV)) {
if (printGOT(TM, Subtarget)) {
// Assemble call via PLT for non-local symbols
if (!(GV->hasHiddenVisibility() || GV->hasProtectedVisibility()) ||
GV->isDeclaration())
O << "@PLT";
}
if (Subtarget->isTargetCygMing() && GV->isDeclaration())
// Save function name for later type emission
FnStubs.insert(Name);
}
}
if (GV->hasExternalWeakLinkage())
ExtWeakSymbols.insert(GV);
int Offset = MO.getOffset();
if (Offset > 0)
O << "+" << Offset;
else if (Offset < 0)
O << Offset;
if (isThreadLocal) {
if (TM.getRelocationModel() == Reloc::PIC_)
O << "@TLSGD"; // general dynamic TLS model
else
if (GV->isDeclaration())
O << "@INDNTPOFF"; // initial exec TLS model
else
O << "@NTPOFF"; // local exec TLS model
} else if (isMemOp) {
if (printGOT(TM, Subtarget)) {
if (Subtarget->GVRequiresExtraLoad(GV, TM, false))
O << "@GOT";
else
O << "@GOTOFF";
} else if (Subtarget->isPICStyleRIPRel() && !NotRIPRel) {
if ((GV->isDeclaration() ||
GV->hasWeakLinkage() ||
GV->hasLinkOnceLinkage()) &&
TM.getRelocationModel() != Reloc::Static)
O << "@GOTPCREL";
if (needCloseParen) {
needCloseParen = false;
O << ')';
}
// Use rip when possible to reduce code size, except when
// index or base register are also part of the address. e.g.
// foo(%rip)(%rcx,%rax,4) is not legal
O << "(%rip)";
}
}
if (needCloseParen)
O << ')';
return;
}
case MachineOperand::MO_ExternalSymbol: {
bool isCallOp = Modifier && !strcmp(Modifier, "call");
bool needCloseParen = false;
std::string Name(TAI->getGlobalPrefix());
Name += MO.getSymbolName();
if (isCallOp && printStub(TM, Subtarget)) {
FnStubs.insert(Name);
O << TAI->getPrivateGlobalPrefix() << Name << "$stub";
return;
}
if (!isCallOp)
O << '$';
else if (Name[0] == '$') {
// The name begins with a dollar-sign. In order to avoid having it look
// like an integer immediate to the assembler, enclose it in parens.
O << '(';
needCloseParen = true;
}
O << Name;
if (printGOT(TM, Subtarget)) {
std::string GOTName(TAI->getGlobalPrefix());
GOTName+="_GLOBAL_OFFSET_TABLE_";
if (Name == GOTName)
// HACK! Emit extra offset to PC during printing GOT offset to
// compensate for the size of popl instruction. The resulting code
// should look like:
// call .piclabel
// piclabel:
// popl %some_register
// addl $_GLOBAL_ADDRESS_TABLE_ + [.-piclabel], %some_register
O << " + [.-"
<< computePICLabel(getFunctionNumber(), TAI, Subtarget) << "]";
if (isCallOp)
O << "@PLT";
}
if (needCloseParen)
O << ')';
if (!isCallOp && Subtarget->isPICStyleRIPRel())
O << "(%rip)";
return;
}
default:
O << "<unknown operand type>"; return;
}
}
void X86ATTAsmPrinter::printSSECC(const MachineInstr *MI, unsigned Op) {
unsigned char value = MI->getOperand(Op).getImmedValue();
assert(value <= 7 && "Invalid ssecc argument!");
switch (value) {
case 0: O << "eq"; break;
case 1: O << "lt"; break;
case 2: O << "le"; break;
case 3: O << "unord"; break;
case 4: O << "neq"; break;
case 5: O << "nlt"; break;
case 6: O << "nle"; break;
case 7: O << "ord"; break;
}
}
void X86ATTAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op,
const char *Modifier){
assert(isMem(MI, Op) && "Invalid memory reference!");
MachineOperand BaseReg = MI->getOperand(Op);
MachineOperand IndexReg = MI->getOperand(Op+2);
const MachineOperand &DispSpec = MI->getOperand(Op+3);
bool NotRIPRel = IndexReg.getReg() || BaseReg.getReg();
if (DispSpec.isGlobalAddress() ||
DispSpec.isConstantPoolIndex() ||
DispSpec.isJumpTableIndex()) {
printOperand(MI, Op+3, "mem", NotRIPRel);
} else {
int DispVal = DispSpec.getImmedValue();
if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg()))
O << DispVal;
}
if (IndexReg.getReg() || BaseReg.getReg()) {
unsigned ScaleVal = MI->getOperand(Op+1).getImmedValue();
unsigned BaseRegOperand = 0, IndexRegOperand = 2;
// There are cases where we can end up with ESP/RSP in the indexreg slot.
// If this happens, swap the base/index register to support assemblers that
// don't work when the index is *SP.
if (IndexReg.getReg() == X86::ESP || IndexReg.getReg() == X86::RSP) {
assert(ScaleVal == 1 && "Scale not supported for stack pointer!");
std::swap(BaseReg, IndexReg);
std::swap(BaseRegOperand, IndexRegOperand);
}
O << "(";
if (BaseReg.getReg())
printOperand(MI, Op+BaseRegOperand, Modifier);
if (IndexReg.getReg()) {
O << ",";
printOperand(MI, Op+IndexRegOperand, Modifier);
if (ScaleVal != 1)
O << "," << ScaleVal;
}
O << ")";
}
}
void X86ATTAsmPrinter::printPICLabel(const MachineInstr *MI, unsigned Op) {
std::string label = computePICLabel(getFunctionNumber(), TAI, Subtarget);
O << label << "\n" << label << ":";
}
bool X86ATTAsmPrinter::printAsmMRegister(const MachineOperand &MO,
const char Mode) {
const MRegisterInfo &RI = *TM.getRegisterInfo();
unsigned Reg = MO.getReg();
switch (Mode) {
default: return true; // Unknown mode.
case 'b': // Print QImode register
Reg = getX86SubSuperRegister(Reg, MVT::i8);
break;
case 'h': // Print QImode high register
Reg = getX86SubSuperRegister(Reg, MVT::i8, true);
break;
case 'w': // Print HImode register
Reg = getX86SubSuperRegister(Reg, MVT::i16);
break;
case 'k': // Print SImode register
Reg = getX86SubSuperRegister(Reg, MVT::i32);
break;
}
O << '%';
for (const char *Name = RI.get(Reg).Name; *Name; ++Name)
O << (char)tolower(*Name);
return false;
}
/// PrintAsmOperand - Print out an operand for an inline asm expression.
///
bool X86ATTAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
unsigned AsmVariant,
const char *ExtraCode) {
// Does this asm operand have a single letter operand modifier?
if (ExtraCode && ExtraCode[0]) {
if (ExtraCode[1] != 0) return true; // Unknown modifier.
switch (ExtraCode[0]) {
default: return true; // Unknown modifier.
case 'c': // Don't print "$" before a global var name or constant.
printOperand(MI, OpNo, "mem");
return false;
case 'b': // Print QImode register
case 'h': // Print QImode high register
case 'w': // Print HImode register
case 'k': // Print SImode register
if (MI->getOperand(OpNo).isReg())
return printAsmMRegister(MI->getOperand(OpNo), ExtraCode[0]);
printOperand(MI, OpNo);
return false;
case 'P': // Don't print @PLT, but do print as memory.
printOperand(MI, OpNo, "mem");
return false;
}
}
printOperand(MI, OpNo);
return false;
}
bool X86ATTAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
unsigned OpNo,
unsigned AsmVariant,
const char *ExtraCode) {
if (ExtraCode && ExtraCode[0])
return true; // Unknown modifier.
printMemReference(MI, OpNo);
return false;
}
/// printMachineInstruction -- Print out a single X86 LLVM instruction
/// MI in AT&T syntax to the current output stream.
///
void X86ATTAsmPrinter::printMachineInstruction(const MachineInstr *MI) {
++EmittedInsts;
// See if a truncate instruction can be turned into a nop.
switch (MI->getOpcode()) {
default: break;
case X86::TRUNC_64to32:
case X86::TRUNC_64to16:
case X86::TRUNC_32to16:
case X86::TRUNC_32to8:
case X86::TRUNC_16to8:
case X86::TRUNC_32_to8:
case X86::TRUNC_16_to8: {
const MachineOperand &MO0 = MI->getOperand(0);
const MachineOperand &MO1 = MI->getOperand(1);
unsigned Reg0 = MO0.getReg();
unsigned Reg1 = MO1.getReg();
unsigned Opc = MI->getOpcode();
if (Opc == X86::TRUNC_64to32)
Reg1 = getX86SubSuperRegister(Reg1, MVT::i32);
else if (Opc == X86::TRUNC_32to16 || Opc == X86::TRUNC_64to16)
Reg1 = getX86SubSuperRegister(Reg1, MVT::i16);
else
Reg1 = getX86SubSuperRegister(Reg1, MVT::i8);
O << TAI->getCommentString() << " TRUNCATE ";
if (Reg0 != Reg1)
O << "\n\t";
break;
}
case X86::PsMOVZX64rr32:
O << TAI->getCommentString() << " ZERO-EXTEND " << "\n\t";
break;
}
// Call the autogenerated instruction printer routines.
printInstruction(MI);
}
// Include the auto-generated portion of the assembly writer.
#include "X86GenAsmWriter.inc"
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