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

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//===-- X86/Printer.cpp - Convert X86 LLVM code to Intel 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 Intel-format assembly language. This
// printer is the output mechanism used by `llc' and `lli -print-machineinstrs'
// on X86.
//
//===----------------------------------------------------------------------===//
#include "X86.h"
#include "X86InstrInfo.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/Mangler.h"
#include "Support/Statistic.h"
#include "Support/StringExtras.h"
#include "Support/CommandLine.h"
using namespace llvm;
namespace {
Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");
// FIXME: This should be automatically picked up by autoconf from the C
// frontend
cl::opt<bool> EmitCygwin("enable-cygwin-compatible-output", cl::Hidden,
cl::desc("Emit X86 assembly code suitable for consumption by cygwin"));
struct Printer : public MachineFunctionPass {
/// Output stream on which we're printing assembly code.
///
std::ostream &O;
/// Target machine description which we query for reg. names, data
/// layout, etc.
///
TargetMachine &TM;
/// Name-mangler for global names.
///
Mangler *Mang;
Printer(std::ostream &o, TargetMachine &tm) : O(o), TM(tm) { }
/// We name each basic block in a Function with a unique number, so
/// that we can consistently refer to them later. This is cleared
/// at the beginning of each call to runOnMachineFunction().
///
typedef std::map<const Value *, unsigned> ValueMapTy;
ValueMapTy NumberForBB;
/// Cache of mangled name for current function. This is
/// recalculated at the beginning of each call to
/// runOnMachineFunction().
///
std::string CurrentFnName;
virtual const char *getPassName() const {
return "X86 Assembly Printer";
}
void checkImplUses (const TargetInstrDescriptor &Desc);
void printMachineInstruction(const MachineInstr *MI);
void printOp(const MachineOperand &MO,
bool elideOffsetKeyword = false);
void printMemReference(const MachineInstr *MI, unsigned Op);
void printConstantPool(MachineConstantPool *MCP);
bool runOnMachineFunction(MachineFunction &F);
bool doInitialization(Module &M);
bool doFinalization(Module &M);
void emitGlobalConstant(const Constant* CV);
void emitConstantValueOnly(const Constant *CV);
};
} // end of anonymous namespace
/// createX86CodePrinterPass - Returns a pass that prints the X86
/// assembly code for a MachineFunction to the given output stream,
/// using the given target machine description. This should work
/// regardless of whether the function is in SSA form.
///
FunctionPass *llvm::createX86CodePrinterPass(std::ostream &o,TargetMachine &tm){
return new Printer(o, tm);
}
/// toOctal - Convert the low order bits of X into an octal digit.
///
static inline char toOctal(int X) {
return (X&7)+'0';
}
/// getAsCString - Return the specified array as a C compatible
/// string, only if the predicate isStringCompatible is true.
///
static void printAsCString(std::ostream &O, const ConstantArray *CVA) {
assert(CVA->isString() && "Array is not string compatible!");
O << "\"";
for (unsigned i = 0; i != CVA->getNumOperands(); ++i) {
unsigned char C = cast<ConstantInt>(CVA->getOperand(i))->getRawValue();
if (C == '"') {
O << "\\\"";
} else if (C == '\\') {
O << "\\\\";
} else if (isprint(C)) {
O << C;
} else {
switch(C) {
case '\b': O << "\\b"; break;
case '\f': O << "\\f"; break;
case '\n': O << "\\n"; break;
case '\r': O << "\\r"; break;
case '\t': O << "\\t"; break;
default:
O << '\\';
O << toOctal(C >> 6);
O << toOctal(C >> 3);
O << toOctal(C >> 0);
break;
}
}
}
O << "\"";
}
// Print out the specified constant, without a storage class. Only the
// constants valid in constant expressions can occur here.
void Printer::emitConstantValueOnly(const Constant *CV) {
if (CV->isNullValue())
O << "0";
else if (const ConstantBool *CB = dyn_cast<ConstantBool>(CV)) {
assert(CB == ConstantBool::True);
O << "1";
} else if (const ConstantSInt *CI = dyn_cast<ConstantSInt>(CV))
if (((CI->getValue() << 32) >> 32) == CI->getValue())
O << CI->getValue();
else
O << (unsigned long long)CI->getValue();
else if (const ConstantUInt *CI = dyn_cast<ConstantUInt>(CV))
O << CI->getValue();
else if (const ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(CV))
// This is a constant address for a global variable or function. Use the
// name of the variable or function as the address value.
O << Mang->getValueName(CPR->getValue());
else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
const TargetData &TD = TM.getTargetData();
switch(CE->getOpcode()) {
case Instruction::GetElementPtr: {
// generate a symbolic expression for the byte address
const Constant *ptrVal = CE->getOperand(0);
std::vector<Value*> idxVec(CE->op_begin()+1, CE->op_end());
if (unsigned Offset = TD.getIndexedOffset(ptrVal->getType(), idxVec)) {
O << "(";
emitConstantValueOnly(ptrVal);
O << ") + " << Offset;
} else {
emitConstantValueOnly(ptrVal);
}
break;
}
case Instruction::Cast: {
// Support only non-converting or widening casts for now, that is, ones
// that do not involve a change in value. This assertion is really gross,
// and may not even be a complete check.
Constant *Op = CE->getOperand(0);
const Type *OpTy = Op->getType(), *Ty = CE->getType();
// Remember, kids, pointers on x86 can be losslessly converted back and
// forth into 32-bit or wider integers, regardless of signedness. :-P
assert(((isa<PointerType>(OpTy)
&& (Ty == Type::LongTy || Ty == Type::ULongTy
|| Ty == Type::IntTy || Ty == Type::UIntTy))
|| (isa<PointerType>(Ty)
&& (OpTy == Type::LongTy || OpTy == Type::ULongTy
|| OpTy == Type::IntTy || OpTy == Type::UIntTy))
|| (((TD.getTypeSize(Ty) >= TD.getTypeSize(OpTy))
&& OpTy->isLosslesslyConvertibleTo(Ty))))
&& "FIXME: Don't yet support this kind of constant cast expr");
O << "(";
emitConstantValueOnly(Op);
O << ")";
break;
}
case Instruction::Add:
O << "(";
emitConstantValueOnly(CE->getOperand(0));
O << ") + (";
emitConstantValueOnly(CE->getOperand(1));
O << ")";
break;
default:
assert(0 && "Unsupported operator!");
}
} else {
assert(0 && "Unknown constant value!");
}
}
// Print a constant value or values, with the appropriate storage class as a
// prefix.
void Printer::emitGlobalConstant(const Constant *CV) {
const TargetData &TD = TM.getTargetData();
if (CV->isNullValue()) {
O << "\t.zero\t " << TD.getTypeSize(CV->getType()) << "\n";
return;
} else if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {
if (CVA->isString()) {
O << "\t.ascii\t";
printAsCString(O, CVA);
O << "\n";
} else { // Not a string. Print the values in successive locations
const std::vector<Use> &constValues = CVA->getValues();
for (unsigned i=0; i < constValues.size(); i++)
emitGlobalConstant(cast<Constant>(constValues[i].get()));
}
return;
} else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) {
// Print the fields in successive locations. Pad to align if needed!
const StructLayout *cvsLayout = TD.getStructLayout(CVS->getType());
const std::vector<Use>& constValues = CVS->getValues();
unsigned sizeSoFar = 0;
for (unsigned i=0, N = constValues.size(); i < N; i++) {
const Constant* field = cast<Constant>(constValues[i].get());
// Check if padding is needed and insert one or more 0s.
unsigned fieldSize = TD.getTypeSize(field->getType());
unsigned padSize = ((i == N-1? cvsLayout->StructSize
: cvsLayout->MemberOffsets[i+1])
- cvsLayout->MemberOffsets[i]) - fieldSize;
sizeSoFar += fieldSize + padSize;
// Now print the actual field value
emitGlobalConstant(field);
// Insert the field padding unless it's zero bytes...
if (padSize)
O << "\t.zero\t " << padSize << "\n";
}
assert(sizeSoFar == cvsLayout->StructSize &&
"Layout of constant struct may be incorrect!");
return;
} else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) {
// FP Constants are printed as integer constants to avoid losing
// precision...
double Val = CFP->getValue();
switch (CFP->getType()->getPrimitiveID()) {
default: assert(0 && "Unknown floating point type!");
case Type::FloatTyID: {
union FU { // Abide by C TBAA rules
float FVal;
unsigned UVal;
} U;
U.FVal = Val;
O << ".long\t" << U.UVal << "\t# float " << Val << "\n";
return;
}
case Type::DoubleTyID: {
union DU { // Abide by C TBAA rules
double FVal;
uint64_t UVal;
} U;
U.FVal = Val;
O << ".quad\t" << U.UVal << "\t# double " << Val << "\n";
return;
}
}
}
const Type *type = CV->getType();
O << "\t";
switch (type->getPrimitiveID()) {
case Type::BoolTyID: case Type::UByteTyID: case Type::SByteTyID:
O << ".byte";
break;
case Type::UShortTyID: case Type::ShortTyID:
O << ".word";
break;
case Type::FloatTyID: case Type::PointerTyID:
case Type::UIntTyID: case Type::IntTyID:
O << ".long";
break;
case Type::DoubleTyID:
case Type::ULongTyID: case Type::LongTyID:
O << ".quad";
break;
default:
assert (0 && "Can't handle printing this type of thing");
break;
}
O << "\t";
emitConstantValueOnly(CV);
O << "\n";
}
/// printConstantPool - Print to the current output stream assembly
/// representations of the constants in the constant pool MCP. This is
/// used to print out constants which have been "spilled to memory" by
/// the code generator.
///
void Printer::printConstantPool(MachineConstantPool *MCP) {
const std::vector<Constant*> &CP = MCP->getConstants();
const TargetData &TD = TM.getTargetData();
if (CP.empty()) return;
for (unsigned i = 0, e = CP.size(); i != e; ++i) {
O << "\t.section .rodata\n";
O << "\t.align " << (unsigned)TD.getTypeAlignment(CP[i]->getType())
<< "\n";
O << ".CPI" << CurrentFnName << "_" << i << ":\t\t\t\t\t#"
<< *CP[i] << "\n";
emitGlobalConstant(CP[i]);
}
}
/// runOnMachineFunction - This uses the printMachineInstruction()
/// method to print assembly for each instruction.
///
bool Printer::runOnMachineFunction(MachineFunction &MF) {
// BBNumber is used here so that a given Printer will never give two
// BBs the same name. (If you have a better way, please let me know!)
static unsigned BBNumber = 0;
O << "\n\n";
// What's my mangled name?
CurrentFnName = Mang->getValueName(MF.getFunction());
// Print out constants referenced by the function
printConstantPool(MF.getConstantPool());
// Print out labels for the function.
O << "\t.text\n";
O << "\t.align 16\n";
O << "\t.globl\t" << CurrentFnName << "\n";
if (!EmitCygwin)
O << "\t.type\t" << CurrentFnName << ", @function\n";
O << CurrentFnName << ":\n";
// Number each basic block so that we can consistently refer to them
// in PC-relative references.
NumberForBB.clear();
for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
I != E; ++I) {
NumberForBB[I->getBasicBlock()] = BBNumber++;
}
// 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.
O << ".LBB" << NumberForBB[I->getBasicBlock()] << ":\t# "
<< I->getBasicBlock()->getName() << "\n";
for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
II != E; ++II) {
// Print the assembly for the instruction.
O << "\t";
printMachineInstruction(II);
}
}
// We didn't modify anything.
return false;
}
static bool isScale(const MachineOperand &MO) {
return MO.isImmediate() &&
(MO.getImmedValue() == 1 || MO.getImmedValue() == 2 ||
MO.getImmedValue() == 4 || MO.getImmedValue() == 8);
}
static bool isMem(const MachineInstr *MI, unsigned Op) {
if (MI->getOperand(Op).isFrameIndex()) return true;
if (MI->getOperand(Op).isConstantPoolIndex()) return true;
return Op+4 <= MI->getNumOperands() &&
MI->getOperand(Op ).isRegister() &&isScale(MI->getOperand(Op+1)) &&
MI->getOperand(Op+2).isRegister() &&MI->getOperand(Op+3).isImmediate();
}
void Printer::printOp(const MachineOperand &MO,
bool elideOffsetKeyword /* = false */) {
const MRegisterInfo &RI = *TM.getRegisterInfo();
switch (MO.getType()) {
case MachineOperand::MO_VirtualRegister:
if (Value *V = MO.getVRegValueOrNull()) {
O << "<" << V->getName() << ">";
return;
}
// FALLTHROUGH
case MachineOperand::MO_MachineRegister:
if (MRegisterInfo::isPhysicalRegister(MO.getReg()))
// Bug Workaround: See note in Printer::doInitialization about %.
O << "%" << RI.get(MO.getReg()).Name;
else
O << "%reg" << MO.getReg();
return;
case MachineOperand::MO_SignExtendedImmed:
case MachineOperand::MO_UnextendedImmed:
O << (int)MO.getImmedValue();
return;
case MachineOperand::MO_PCRelativeDisp: {
ValueMapTy::const_iterator i = NumberForBB.find(MO.getVRegValue());
assert (i != NumberForBB.end()
&& "Could not find a BB in the NumberForBB map!");
O << ".LBB" << i->second << " # PC rel: " << MO.getVRegValue()->getName();
return;
}
case MachineOperand::MO_GlobalAddress:
if (!elideOffsetKeyword)
O << "OFFSET ";
O << Mang->getValueName(MO.getGlobal());
return;
case MachineOperand::MO_ExternalSymbol:
O << MO.getSymbolName();
return;
default:
O << "<unknown operand type>"; return;
}
}
static const char* const sizePtr(const TargetInstrDescriptor &Desc) {
switch (Desc.TSFlags & X86II::MemMask) {
default: assert(0 && "Unknown arg size!");
case X86II::Mem8: return "BYTE PTR";
case X86II::Mem16: return "WORD PTR";
case X86II::Mem32: return "DWORD PTR";
case X86II::Mem64: return "QWORD PTR";
case X86II::Mem80: return "XWORD PTR";
}
}
void Printer::printMemReference(const MachineInstr *MI, unsigned Op) {
assert(isMem(MI, Op) && "Invalid memory reference!");
if (MI->getOperand(Op).isFrameIndex()) {
O << "[frame slot #" << MI->getOperand(Op).getFrameIndex();
if (MI->getOperand(Op+3).getImmedValue())
O << " + " << MI->getOperand(Op+3).getImmedValue();
O << "]";
return;
} else if (MI->getOperand(Op).isConstantPoolIndex()) {
O << "[.CPI" << CurrentFnName << "_"
<< MI->getOperand(Op).getConstantPoolIndex();
if (MI->getOperand(Op+3).getImmedValue())
O << " + " << MI->getOperand(Op+3).getImmedValue();
O << "]";
return;
}
const MachineOperand &BaseReg = MI->getOperand(Op);
int ScaleVal = MI->getOperand(Op+1).getImmedValue();
const MachineOperand &IndexReg = MI->getOperand(Op+2);
int DispVal = MI->getOperand(Op+3).getImmedValue();
O << "[";
bool NeedPlus = false;
if (BaseReg.getReg()) {
printOp(BaseReg);
NeedPlus = true;
}
if (IndexReg.getReg()) {
if (NeedPlus) O << " + ";
if (ScaleVal != 1)
O << ScaleVal << "*";
printOp(IndexReg);
NeedPlus = true;
}
if (DispVal) {
if (NeedPlus)
if (DispVal > 0)
O << " + ";
else {
O << " - ";
DispVal = -DispVal;
}
O << DispVal;
}
O << "]";
}
/// checkImplUses - Emit the implicit-use registers for the
/// instruction described by DESC, if its PrintImplUses flag is set.
///
void Printer::checkImplUses (const TargetInstrDescriptor &Desc) {
const MRegisterInfo &RI = *TM.getRegisterInfo();
if (Desc.TSFlags & X86II::PrintImplUses) {
for (const unsigned *p = Desc.ImplicitUses; *p; ++p) {
// Bug Workaround: See note in Printer::doInitialization about %.
O << ", %" << RI.get(*p).Name;
}
}
}
/// printMachineInstruction -- Print out a single X86 LLVM instruction
/// MI in Intel syntax to the current output stream.
///
void Printer::printMachineInstruction(const MachineInstr *MI) {
unsigned Opcode = MI->getOpcode();
const TargetInstrInfo &TII = TM.getInstrInfo();
const TargetInstrDescriptor &Desc = TII.get(Opcode);
++EmittedInsts;
switch (Desc.TSFlags & X86II::FormMask) {
case X86II::Pseudo:
// Print pseudo-instructions as comments; either they should have been
// turned into real instructions by now, or they don't need to be
// seen by the assembler (e.g., IMPLICIT_USEs.)
O << "# ";
if (Opcode == X86::PHI) {
printOp(MI->getOperand(0));
O << " = phi ";
for (unsigned i = 1, e = MI->getNumOperands(); i != e; i+=2) {
if (i != 1) O << ", ";
O << "[";
printOp(MI->getOperand(i));
O << ", ";
printOp(MI->getOperand(i+1));
O << "]";
}
} else {
unsigned i = 0;
if (MI->getNumOperands() && MI->getOperand(0).isDef()) {
printOp(MI->getOperand(0));
O << " = ";
++i;
}
O << TII.getName(MI->getOpcode());
for (unsigned e = MI->getNumOperands(); i != e; ++i) {
O << " ";
if (MI->getOperand(i).isDef()) O << "*";
printOp(MI->getOperand(i));
if (MI->getOperand(i).isDef()) O << "*";
}
}
O << "\n";
return;
case X86II::RawFrm:
// The accepted forms of Raw instructions are:
// 1. nop - No operand required
// 2. jmp foo - PC relative displacement operand
// 3. call bar - GlobalAddress Operand or External Symbol Operand
//
assert(MI->getNumOperands() == 0 ||
(MI->getNumOperands() == 1 &&
(MI->getOperand(0).isPCRelativeDisp() ||
MI->getOperand(0).isGlobalAddress() ||
MI->getOperand(0).isExternalSymbol())) &&
"Illegal raw instruction!");
O << TII.getName(MI->getOpcode()) << " ";
if (MI->getNumOperands() == 1) {
printOp(MI->getOperand(0), true); // Don't print "OFFSET"...
}
O << "\n";
return;
case X86II::AddRegFrm: {
// There are currently two forms of acceptable AddRegFrm instructions.
// Either the instruction JUST takes a single register (like inc, dec, etc),
// or it takes a register and an immediate of the same size as the register
// (move immediate f.e.). Note that this immediate value might be stored as
// an LLVM value, to represent, for example, loading the address of a global
// into a register. The initial register might be duplicated if this is a
// M_2_ADDR_REG instruction
//
assert(MI->getOperand(0).isRegister() &&
(MI->getNumOperands() == 1 ||
(MI->getNumOperands() == 2 &&
(MI->getOperand(1).getVRegValueOrNull() ||
MI->getOperand(1).isImmediate() ||
MI->getOperand(1).isRegister() ||
MI->getOperand(1).isGlobalAddress() ||
MI->getOperand(1).isExternalSymbol()))) &&
"Illegal form for AddRegFrm instruction!");
unsigned Reg = MI->getOperand(0).getReg();
O << TII.getName(MI->getOpcode()) << " ";
printOp(MI->getOperand(0));
if (MI->getNumOperands() == 2 &&
(!MI->getOperand(1).isRegister() ||
MI->getOperand(1).getVRegValueOrNull() ||
MI->getOperand(1).isGlobalAddress() ||
MI->getOperand(1).isExternalSymbol())) {
O << ", ";
printOp(MI->getOperand(1));
}
checkImplUses(Desc);
O << "\n";
return;
}
case X86II::MRMDestReg: {
// There are three forms of MRMDestReg instructions, those with 2
// or 3 operands:
//
// 2 Operands: this is for things like mov that do not read a
// second input.
//
// 2 Operands: two address instructions which def&use the first
// argument and use the second as input.
//
// 3 Operands: in this form, two address instructions are the same
// as in 2 but have a constant argument as well.
//
bool isTwoAddr = TII.isTwoAddrInstr(Opcode);
assert(MI->getOperand(0).isRegister() &&
(MI->getNumOperands() == 2 ||
(MI->getNumOperands() == 3 && MI->getOperand(2).isImmediate()))
&& "Bad format for MRMDestReg!");
O << TII.getName(MI->getOpcode()) << " ";
printOp(MI->getOperand(0));
O << ", ";
printOp(MI->getOperand(1));
if (MI->getNumOperands() == 3) {
O << ", ";
printOp(MI->getOperand(2));
}
O << "\n";
return;
}
case X86II::MRMDestMem: {
// These instructions are the same as MRMDestReg, but instead of having a
// register reference for the mod/rm field, it's a memory reference.
//
assert(isMem(MI, 0) &&
(MI->getNumOperands() == 4+1 ||
(MI->getNumOperands() == 4+2 && MI->getOperand(5).isImmediate()))
&& "Bad format for MRMDestMem!");
O << TII.getName(MI->getOpcode()) << " " << sizePtr(Desc) << " ";
printMemReference(MI, 0);
O << ", ";
printOp(MI->getOperand(4));
if (MI->getNumOperands() == 4+2) {
O << ", ";
printOp(MI->getOperand(5));
}
O << "\n";
return;
}
case X86II::MRMSrcReg: {
// There are three forms that are acceptable for MRMSrcReg
// instructions, those with 2 or 3 operands:
//
// 2 Operands: this is for things like mov that do not read a
// second input.
//
// 2 Operands: in this form, the last register is the ModR/M
// input. The first operand is a def&use. This is for things
// like: add r32, r/m32
//
// 3 Operands: in this form, we can have 'INST R1, R2, imm', which is used
// for instructions like the IMULrri instructions.
//
//
assert(MI->getOperand(0).isRegister() &&
MI->getOperand(1).isRegister() &&
(MI->getNumOperands() == 2 ||
(MI->getNumOperands() == 3 &&
(MI->getOperand(2).isImmediate())))
&& "Bad format for MRMSrcReg!");
O << TII.getName(MI->getOpcode()) << " ";
printOp(MI->getOperand(0));
O << ", ";
printOp(MI->getOperand(1));
if (MI->getNumOperands() == 3) {
O << ", ";
printOp(MI->getOperand(2));
}
O << "\n";
return;
}
case X86II::MRMSrcMem: {
// These instructions are the same as MRMSrcReg, but instead of having a
// register reference for the mod/rm field, it's a memory reference.
//
assert(MI->getOperand(0).isRegister() &&
(MI->getNumOperands() == 1+4 && isMem(MI, 1)) ||
(MI->getNumOperands() == 2+4 && MI->getOperand(5).isImmediate() && isMem(MI, 1))
&& "Bad format for MRMSrcMem!");
O << TII.getName(MI->getOpcode()) << " ";
printOp(MI->getOperand(0));
O << ", " << sizePtr(Desc) << " ";
printMemReference(MI, 1);
if (MI->getNumOperands() == 2+4) {
O << ", ";
printOp(MI->getOperand(5));
}
O << "\n";
return;
}
case X86II::MRM0r: case X86II::MRM1r:
case X86II::MRM2r: case X86II::MRM3r:
case X86II::MRM4r: case X86II::MRM5r:
case X86II::MRM6r: case X86II::MRM7r: {
// In this form, the following are valid formats:
// 1. sete r
// 2. cmp reg, immediate
// 2. shl rdest, rinput <implicit CL or 1>
// 3. sbb rdest, rinput, immediate [rdest = rinput]
//
assert(MI->getNumOperands() > 0 && MI->getNumOperands() < 4 &&
MI->getOperand(0).isRegister() && "Bad MRMSxR format!");
assert((MI->getNumOperands() != 2 ||
MI->getOperand(1).isRegister() || MI->getOperand(1).isImmediate())&&
"Bad MRMSxR format!");
assert((MI->getNumOperands() < 3 ||
(MI->getOperand(1).isRegister() && MI->getOperand(2).isImmediate())) &&
"Bad MRMSxR format!");
if (MI->getNumOperands() > 1 && MI->getOperand(1).isRegister() &&
MI->getOperand(0).getReg() != MI->getOperand(1).getReg())
O << "**";
O << TII.getName(MI->getOpcode()) << " ";
printOp(MI->getOperand(0));
if (MI->getOperand(MI->getNumOperands()-1).isImmediate()) {
O << ", ";
printOp(MI->getOperand(MI->getNumOperands()-1));
}
checkImplUses(Desc);
O << "\n";
return;
}
case X86II::MRM0m: case X86II::MRM1m:
case X86II::MRM2m: case X86II::MRM3m:
case X86II::MRM4m: case X86II::MRM5m:
case X86II::MRM6m: case X86II::MRM7m: {
// In this form, the following are valid formats:
// 1. sete [m]
// 2. cmp [m], immediate
// 2. shl [m], rinput <implicit CL or 1>
// 3. sbb [m], immediate
//
assert(MI->getNumOperands() >= 4 && MI->getNumOperands() <= 5 &&
isMem(MI, 0) && "Bad MRMSxM format!");
assert((MI->getNumOperands() != 5 ||
(MI->getOperand(4).isImmediate() ||
MI->getOperand(4).isGlobalAddress())) &&
"Bad MRMSxM format!");
const MachineOperand &Op3 = MI->getOperand(3);
// Bug: The 80-bit FP store-pop instruction "fstp XWORD PTR [...]"
// is misassembled by gas in intel_syntax mode as its 32-bit
// equivalent "fstp DWORD PTR [...]". Workaround: Output the raw
// opcode bytes instead of the instruction.
if (MI->getOpcode() == X86::FSTP80m) {
if ((MI->getOperand(0).getReg() == X86::ESP)
&& (MI->getOperand(1).getImmedValue() == 1)) {
if (Op3.isImmediate() &&
Op3.getImmedValue() >= -128 && Op3.getImmedValue() <= 127) {
// 1 byte disp.
O << ".byte 0xdb, 0x7c, 0x24, 0x" << std::hex
<< ((unsigned)Op3.getImmedValue() & 255) << std::dec << "\t# ";
} else {
O << ".byte 0xdb, 0xbc, 0x24\n\t";
O << ".long ";
printOp(Op3);
O << "\t# ";
}
}
}
// Bug: The 80-bit FP load instruction "fld XWORD PTR [...]" is
// misassembled by gas in intel_syntax mode as its 32-bit
// equivalent "fld DWORD PTR [...]". Workaround: Output the raw
// opcode bytes instead of the instruction.
if (MI->getOpcode() == X86::FLD80m &&
MI->getOperand(0).getReg() == X86::ESP &&
MI->getOperand(1).getImmedValue() == 1) {
if (Op3.isImmediate() && Op3.getImmedValue() >= -128 &&
Op3.getImmedValue() <= 127) { // 1 byte displacement
O << ".byte 0xdb, 0x6c, 0x24, 0x" << std::hex
<< ((unsigned)Op3.getImmedValue() & 255) << std::dec << "\t# ";
} else {
O << ".byte 0xdb, 0xac, 0x24\n\t";
O << ".long ";
printOp(Op3);
O << "\t# ";
}
}
// Bug: gas intel_syntax mode treats "fild QWORD PTR [...]" as an
// invalid opcode, saying "64 bit operations are only supported in
// 64 bit modes." libopcodes disassembles it as "fild DWORD PTR
// [...]", which is wrong. Workaround: Output the raw opcode bytes
// instead of the instruction.
if (MI->getOpcode() == X86::FILD64m &&
MI->getOperand(0).getReg() == X86::ESP &&
MI->getOperand(1).getImmedValue() == 1) {
if (Op3.isImmediate() && Op3.getImmedValue() >= -128 &&
Op3.getImmedValue() <= 127) { // 1 byte displacement
O << ".byte 0xdf, 0x6c, 0x24, 0x" << std::hex
<< ((unsigned)Op3.getImmedValue() & 255) << std::dec << "\t# ";
} else {
O << ".byte 0xdf, 0xac, 0x24\n\t";
O << ".long ";
printOp(Op3);
O << std::dec << "\t# ";
}
}
// Bug: gas intel_syntax mode treats "fistp QWORD PTR [...]" as
// an invalid opcode, saying "64 bit operations are only
// supported in 64 bit modes." libopcodes disassembles it as
// "fistpll DWORD PTR [...]", which is wrong. Workaround: Output
// "fistpll DWORD PTR " instead, which is what libopcodes is
// expecting to see.
if (MI->getOpcode() == X86::FISTP64m) {
O << "fistpll DWORD PTR ";
printMemReference(MI, 0);
if (MI->getNumOperands() == 5) {
O << ", ";
printOp(MI->getOperand(4));
}
O << "\t# ";
}
O << TII.getName(MI->getOpcode()) << " ";
O << sizePtr(Desc) << " ";
printMemReference(MI, 0);
if (MI->getNumOperands() == 5) {
O << ", ";
printOp(MI->getOperand(4));
}
O << "\n";
return;
}
default:
O << "\tUNKNOWN FORM:\t\t-"; MI->print(O, TM); break;
}
}
bool Printer::doInitialization(Module &M) {
// Tell gas we are outputting Intel syntax (not AT&T syntax) assembly.
//
// Bug: gas in `intel_syntax noprefix' mode interprets the symbol `Sp' in an
// instruction as a reference to the register named sp, and if you try to
// reference a symbol `Sp' (e.g. `mov ECX, OFFSET Sp') then it gets lowercased
// before being looked up in the symbol table. This creates spurious
// `undefined symbol' errors when linking. Workaround: Do not use `noprefix'
// mode, and decorate all register names with percent signs.
O << "\t.intel_syntax\n";
Mang = new Mangler(M, EmitCygwin);
return false; // success
}
// SwitchSection - Switch to the specified section of the executable if we are
// not already in it!
//
static void SwitchSection(std::ostream &OS, std::string &CurSection,
const char *NewSection) {
if (CurSection != NewSection) {
CurSection = NewSection;
if (!CurSection.empty())
OS << "\t" << NewSection << "\n";
}
}
bool Printer::doFinalization(Module &M) {
const TargetData &TD = TM.getTargetData();
std::string CurSection;
// Print out module-level global variables here.
for (Module::const_giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
if (I->hasInitializer()) { // External global require no code
O << "\n\n";
std::string name = Mang->getValueName(I);
Constant *C = I->getInitializer();
unsigned Size = TD.getTypeSize(C->getType());
unsigned Align = TD.getTypeAlignment(C->getType());
if (C->isNullValue() &&
(I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
I->hasWeakLinkage() /* FIXME: Verify correct */)) {
SwitchSection(O, CurSection, ".data");
if (I->hasInternalLinkage())
O << "\t.local " << name << "\n";
O << "\t.comm " << name << "," << TD.getTypeSize(C->getType())
<< "," << (unsigned)TD.getTypeAlignment(C->getType());
O << "\t\t# ";
WriteAsOperand(O, I, true, true, &M);
O << "\n";
} else {
switch (I->getLinkage()) {
case GlobalValue::LinkOnceLinkage:
case GlobalValue::WeakLinkage: // FIXME: Verify correct for weak.
// Nonnull linkonce -> weak
O << "\t.weak " << name << "\n";
SwitchSection(O, CurSection, "");
O << "\t.section\t.llvm.linkonce.d." << name << ",\"aw\",@progbits\n";
break;
case GlobalValue::AppendingLinkage:
// FIXME: appending linkage variables should go into a section of
// their name or something. For now, just emit them as external.
case GlobalValue::ExternalLinkage:
// If external or appending, declare as a global symbol
O << "\t.globl " << name << "\n";
// FALL THROUGH
case GlobalValue::InternalLinkage:
if (C->isNullValue())
SwitchSection(O, CurSection, ".bss");
else
SwitchSection(O, CurSection, ".data");
break;
}
O << "\t.align " << Align << "\n";
O << "\t.type " << name << ",@object\n";
O << "\t.size " << name << "," << Size << "\n";
O << name << ":\t\t\t\t# ";
WriteAsOperand(O, I, true, true, &M);
O << " = ";
WriteAsOperand(O, C, false, false, &M);
O << "\n";
emitGlobalConstant(C);
}
}
delete Mang;
return false; // success
}
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