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Give the X86 JIT the ability to encode global+disp constants. Patch

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contributed by Jeff Cohen!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17010 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-10-15 04:53:13 +00:00
parent d416f086cc
commit 8cce7cd0ae
1 changed files with 54 additions and 27 deletions
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81
lib/Target/X86/X86CodeEmitter.cpp
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@ -193,7 +193,7 @@ namespace {
void emitPCRelativeBlockAddress(const MachineBasicBlock *BB);
void emitMaybePCRelativeValue(unsigned Address, bool isPCRelative);
void emitGlobalAddressForCall(GlobalValue *GV);
void emitGlobalAddressForPtr(GlobalValue *GV);
void emitGlobalAddressForPtr(GlobalValue *GV, int Disp = 0);
void emitRegModRMByte(unsigned ModRMReg, unsigned RegOpcodeField);
void emitSIBByte(unsigned SS, unsigned Index, unsigned Base);
@ -294,7 +294,7 @@ void Emitter::emitGlobalAddressForCall(GlobalValue *GV) {
/// this is part of a "take the address of a global" instruction, which is not
/// PC relative.
///
void Emitter::emitGlobalAddressForPtr(GlobalValue *GV) {
void Emitter::emitGlobalAddressForPtr(GlobalValue *GV, int Disp /* = 0 */) {
// Get the address from the backend...
unsigned Address = MCE.getGlobalValueAddress(GV);
@ -306,7 +306,7 @@ void Emitter::emitGlobalAddressForPtr(GlobalValue *GV) {
Address = getResolver(MCE).getLazyResolver((Function*)GV);
}
emitMaybePCRelativeValue(Address, false);
emitMaybePCRelativeValue(Address + Disp, false);
}
@ -374,14 +374,25 @@ static bool isDisp8(int Value) {
void Emitter::emitMemModRMByte(const MachineInstr &MI,
unsigned Op, unsigned RegOpcodeField) {
const MachineOperand &Disp = MI.getOperand(Op+3);
const MachineOperand &Op3 = MI.getOperand(Op+3);
GlobalValue *GV = 0;
int DispVal = 0;
if (Op3.isGlobalAddress()) {
GV = Op3.getGlobal();
DispVal = Op3.getOffset();
} else {
DispVal = Op3.getImmedValue();
}
if (MI.getOperand(Op).isConstantPoolIndex()) {
// Emit a direct address reference [disp32] where the displacement of the
// constant pool entry is controlled by the MCE.
assert(!GV && "Constant Pool reference cannot be relative to global!");
MCE.emitByte(ModRMByte(0, RegOpcodeField, 5));
unsigned Index = MI.getOperand(Op).getConstantPoolIndex();
unsigned Address = MCE.getConstantPoolEntryAddress(Index);
MCE.emitWord(Address+Disp.getImmedValue());
MCE.emitWord(Address+DispVal);
return;
}
@ -394,20 +405,27 @@ void Emitter::emitMemModRMByte(const MachineInstr &MI,
if (BaseReg.getReg() == 0) { // Just a displacement?
// Emit special case [disp32] encoding
MCE.emitByte(ModRMByte(0, RegOpcodeField, 5));
emitConstant(Disp.getImmedValue(), 4);
if (GV)
emitGlobalAddressForPtr(GV, DispVal);
else
emitConstant(DispVal, 4);
} else {
unsigned BaseRegNo = getX86RegNum(BaseReg.getReg());
if (Disp.getImmedValue() == 0 && BaseRegNo != N86::EBP) {
if (GV) {
// Emit the most general non-SIB encoding: [REG+disp32]
MCE.emitByte(ModRMByte(2, RegOpcodeField, BaseRegNo));
emitGlobalAddressForPtr(GV, DispVal);
} else if (DispVal == 0 && BaseRegNo != N86::EBP) {
// Emit simple indirect register encoding... [EAX] f.e.
MCE.emitByte(ModRMByte(0, RegOpcodeField, BaseRegNo));
} else if (isDisp8(Disp.getImmedValue())) {
} else if (isDisp8(DispVal)) {
// Emit the disp8 encoding... [REG+disp8]
MCE.emitByte(ModRMByte(1, RegOpcodeField, BaseRegNo));
emitConstant(Disp.getImmedValue(), 1);
emitConstant(DispVal, 1);
} else {
// Emit the most general non-SIB encoding: [REG+disp32]
MCE.emitByte(ModRMByte(2, RegOpcodeField, BaseRegNo));
emitConstant(Disp.getImmedValue(), 4);
emitConstant(DispVal, 4);
}
}
@ -421,10 +439,14 @@ void Emitter::emitMemModRMByte(const MachineInstr &MI,
// MOD=0, BASE=5, to JUST get the index, scale, and displacement.
MCE.emitByte(ModRMByte(0, RegOpcodeField, 4));
ForceDisp32 = true;
} else if (Disp.getImmedValue() == 0 && BaseReg.getReg() != X86::EBP) {
} else if (GV) {
// Emit the normal disp32 encoding...
MCE.emitByte(ModRMByte(2, RegOpcodeField, 4));
ForceDisp32 = true;
} else if (DispVal == 0 && BaseReg.getReg() != X86::EBP) {
// Emit no displacement ModR/M byte
MCE.emitByte(ModRMByte(0, RegOpcodeField, 4));
} else if (isDisp8(Disp.getImmedValue())) {
} else if (isDisp8(DispVal)) {
// Emit the disp8 encoding...
MCE.emitByte(ModRMByte(1, RegOpcodeField, 4));
ForceDisp8 = true; // Make sure to force 8 bit disp if Base=EBP
@ -446,18 +468,20 @@ void Emitter::emitMemModRMByte(const MachineInstr &MI,
unsigned BaseRegNo = getX86RegNum(BaseReg.getReg());
unsigned IndexRegNo;
if (IndexReg.getReg())
IndexRegNo = getX86RegNum(IndexReg.getReg());
IndexRegNo = getX86RegNum(IndexReg.getReg());
else
IndexRegNo = 4; // For example [ESP+1*<noreg>+4]
IndexRegNo = 4; // For example [ESP+1*<noreg>+4]
emitSIBByte(SS, IndexRegNo, BaseRegNo);
}
// Do we need to output a displacement?
if (Disp.getImmedValue() != 0 || ForceDisp32 || ForceDisp8) {
if (!ForceDisp32 && isDisp8(Disp.getImmedValue()))
emitConstant(Disp.getImmedValue(), 1);
if (DispVal != 0 || ForceDisp32 || ForceDisp8) {
if (!ForceDisp32 && isDisp8(DispVal))
emitConstant(DispVal, 1);
else if (GV)
emitGlobalAddressForPtr(GV, DispVal);
else
emitConstant(Disp.getImmedValue(), 4);
emitConstant(DispVal, 4);
}
}
}
@ -492,8 +516,8 @@ void Emitter::emitInstruction(const MachineInstr &MI) {
case X86II::D8: case X86II::D9: case X86II::DA: case X86II::DB:
case X86II::DC: case X86II::DD: case X86II::DE: case X86II::DF:
MCE.emitByte(0xD8+
(((Desc.TSFlags & X86II::Op0Mask)-X86II::D8)
>> X86II::Op0Shift));
(((Desc.TSFlags & X86II::Op0Mask)-X86II::D8)
>> X86II::Op0Shift));
break; // Two-byte opcode prefix
default: assert(0 && "Invalid prefix!");
case 0: break; // No prefix!
@ -525,7 +549,7 @@ void Emitter::emitInstruction(const MachineInstr &MI) {
} else if (MO.isImmediate()) {
emitConstant(MO.getImmedValue(), sizeOfImm(Desc));
} else {
assert(0 && "Unknown RawFrm operand!");
assert(0 && "Unknown RawFrm operand!");
}
}
break;
@ -535,15 +559,17 @@ void Emitter::emitInstruction(const MachineInstr &MI) {
if (MI.getNumOperands() == 2) {
const MachineOperand &MO1 = MI.getOperand(1);
if (Value *V = MO1.getVRegValueOrNull()) {
assert(sizeOfImm(Desc) == 4 && "Don't know how to emit non-pointer values!");
assert(sizeOfImm(Desc) == 4 &&
"Don't know how to emit non-pointer values!");
emitGlobalAddressForPtr(cast<GlobalValue>(V));
} else if (MO1.isGlobalAddress()) {
assert(sizeOfImm(Desc) == 4 && "Don't know how to emit non-pointer values!");
assert(sizeOfImm(Desc) == 4 &&
"Don't know how to emit non-pointer values!");
assert(!MO1.isPCRelative() && "Function pointer ref is PC relative?");
emitGlobalAddressForPtr(MO1.getGlobal());
emitGlobalAddressForPtr(MO1.getGlobal(), MO1.getOffset());
} else if (MO1.isExternalSymbol()) {
assert(sizeOfImm(Desc) == 4 && "Don't know how to emit non-pointer values!");
assert(sizeOfImm(Desc) == 4 &&
"Don't know how to emit non-pointer values!");
unsigned Address = MCE.getGlobalValueAddress(MO1.getSymbolName());
assert(Address && "Unknown external symbol!");
emitMaybePCRelativeValue(Address, MO1.isPCRelative());
@ -608,7 +634,8 @@ void Emitter::emitInstruction(const MachineInstr &MI) {
if (MI.getOperand(4).isImmediate())
emitConstant(MI.getOperand(4).getImmedValue(), sizeOfImm(Desc));
else if (MI.getOperand(4).isGlobalAddress())
emitGlobalAddressForPtr(MI.getOperand(4).getGlobal());
emitGlobalAddressForPtr(MI.getOperand(4).getGlobal(),
MI.getOperand(4).getOffset());
else
assert(0 && "Unknown operand!");
}