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simplify displacement handling, emit displacements by-operand

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even for the immediate case.  No functionality change.

llvm-svn: 95770
This commit is contained in:
Chris Lattner 2010-02-10 06:30:00 +00:00
parent ff8027e33a
commit aa22470a1a
1 changed files with 19 additions and 50 deletions
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69
lib/Target/X86/X86MCCodeEmitter.cpp
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@ -68,8 +68,8 @@ public:
}
}
void EmitDisplacementField(const MCOperand *RelocOp, int DispVal,
int64_t Adj, bool IsPCRel, raw_ostream &OS) const;
void EmitDisplacementField(const MCOperand &Disp, int64_t Adj, bool IsPCRel,
raw_ostream &OS) const;
inline static unsigned char ModRMByte(unsigned Mod, unsigned RegOpcode,
unsigned RM) {
@ -119,12 +119,12 @@ static bool isDisp8(int Value) {
}
void X86MCCodeEmitter::
EmitDisplacementField(const MCOperand *RelocOp, int DispVal,
int64_t Adj, bool IsPCRel, raw_ostream &OS) const {
EmitDisplacementField(const MCOperand &DispOp, int64_t Adj, bool IsPCRel,
raw_ostream &OS) const {
// If this is a simple integer displacement that doesn't require a relocation,
// emit it now.
if (!RelocOp) {
EmitConstant(DispVal, 4, OS);
if (DispOp.isImm()) {
EmitConstant(DispOp.getImm(), 4, OS);
return;
}
@ -159,39 +159,8 @@ EmitDisplacementField(const MCOperand *RelocOp, int DispVal,
void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
unsigned RegOpcodeField,
intptr_t PCAdj,
raw_ostream &OS) const {
const MCOperand &Op3 = MI.getOperand(Op+3);
int DispVal = 0;
const MCOperand *DispForReloc = 0;
// Figure out what sort of displacement we have to handle here.
if (Op3.isImm()) {
DispVal = Op3.getImm();
} else {
assert(0 && "relocatable operand");
#if 0
if (Op3.isGlobal()) {
DispForReloc = &Op3;
} else if (Op3.isSymbol()) {
DispForReloc = &Op3;
} else if (Op3.isCPI()) {
if (!MCE.earlyResolveAddresses() || Is64BitMode || IsPIC) {
DispForReloc = &Op3;
} else {
DispVal += MCE.getConstantPoolEntryAddress(Op3.getIndex());
DispVal += Op3.getOffset();
}
} else {
assert(Op3.isJTI());
if (!MCE.earlyResolveAddresses() || Is64BitMode || IsPIC) {
DispForReloc = &Op3;
} else {
DispVal += MCE.getJumpTableEntryAddress(Op3.getIndex());
}
#endif
}
intptr_t PCAdj, raw_ostream &OS) const {
const MCOperand &Disp = MI.getOperand(Op+3);
const MCOperand &Base = MI.getOperand(Op);
const MCOperand &Scale = MI.getOperand(Op+1);
const MCOperand &IndexReg = MI.getOperand(Op+2);
@ -215,7 +184,7 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
if (BaseReg == 0 || // [disp32] in X86-32 mode
BaseReg == X86::RIP) { // [disp32+RIP] in X86-64 mode
EmitByte(ModRMByte(0, RegOpcodeField, 5), OS);
EmitDisplacementField(DispForReloc, DispVal, PCAdj, true, OS);
EmitDisplacementField(Disp, PCAdj, true, OS);
return;
}
@ -225,21 +194,21 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
// indirect register encoding, this handles addresses like [EAX]. The
// encoding for [EBP] with no displacement means [disp32] so we handle it
// by emitting a displacement of 0 below.
if (!DispForReloc && DispVal == 0 && BaseRegNo != N86::EBP) {
if (Disp.isImm() && Disp.getImm() == 0 && BaseRegNo != N86::EBP) {
EmitByte(ModRMByte(0, RegOpcodeField, BaseRegNo), OS);
return;
}
// Otherwise, if the displacement fits in a byte, encode as [REG+disp8].
if (!DispForReloc && isDisp8(DispVal)) {
if (Disp.isImm() && isDisp8(Disp.getImm())) {
EmitByte(ModRMByte(1, RegOpcodeField, BaseRegNo), OS);
EmitConstant(DispVal, 1, OS);
EmitConstant(Disp.getImm(), 1, OS);
return;
}
// Otherwise, emit the most general non-SIB encoding: [REG+disp32]
EmitByte(ModRMByte(2, RegOpcodeField, BaseRegNo), OS);
EmitDisplacementField(DispForReloc, DispVal, PCAdj, IsPCRel, OS);
EmitDisplacementField(Disp, PCAdj, IsPCRel, OS);
return;
}
@ -254,14 +223,14 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
// MOD=0, BASE=5, to JUST get the index, scale, and displacement.
EmitByte(ModRMByte(0, RegOpcodeField, 4), OS);
ForceDisp32 = true;
} else if (DispForReloc) {
} else if (!Disp.isImm()) {
// Emit the normal disp32 encoding.
EmitByte(ModRMByte(2, RegOpcodeField, 4), OS);
ForceDisp32 = true;
} else if (DispVal == 0 && BaseReg != X86::EBP) {
} else if (Disp.getImm() == 0 && BaseReg != X86::EBP) {
// Emit no displacement ModR/M byte
EmitByte(ModRMByte(0, RegOpcodeField, 4), OS);
} else if (isDisp8(DispVal)) {
} else if (isDisp8(Disp.getImm())) {
// Emit the disp8 encoding.
EmitByte(ModRMByte(1, RegOpcodeField, 4), OS);
ForceDisp8 = true; // Make sure to force 8 bit disp if Base=EBP
@ -294,9 +263,9 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op,
// Do we need to output a displacement?
if (ForceDisp8)
EmitConstant(DispVal, 1, OS);
else if (DispVal != 0 || ForceDisp32)
EmitDisplacementField(DispForReloc, DispVal, PCAdj, IsPCRel, OS);
EmitConstant(Disp.getImm(), 1, OS);
else if (ForceDisp32 || Disp.getImm() != 0)
EmitDisplacementField(Disp, PCAdj, IsPCRel, OS);
}
/// DetermineREXPrefix - Determine if the MCInst has to be encoded with a X86-64