From 37ce80eca3159b3a7654cc34ea9c1202f38335ca Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 10 Feb 2010 06:41:02 +0000 Subject: [PATCH] keep track of what the current byte being emitted is throughout the X86 encoder. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95771 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/X86MCCodeEmitter.cpp | 161 +++++++++++++++------------- 1 file changed, 87 insertions(+), 74 deletions(-) diff --git a/lib/Target/X86/X86MCCodeEmitter.cpp b/lib/Target/X86/X86MCCodeEmitter.cpp index f55ef77cc3a..4c1d3d3d790 100644 --- a/lib/Target/X86/X86MCCodeEmitter.cpp +++ b/lib/Target/X86/X86MCCodeEmitter.cpp @@ -56,20 +56,22 @@ public: return X86RegisterInfo::getX86RegNum(MO.getReg()); } - void EmitByte(unsigned char C, raw_ostream &OS) const { + void EmitByte(unsigned char C, unsigned &CurByte, raw_ostream &OS) const { OS << (char)C; + ++CurByte; } - void EmitConstant(uint64_t Val, unsigned Size, raw_ostream &OS) const { + void EmitConstant(uint64_t Val, unsigned Size, unsigned &CurByte, + raw_ostream &OS) const { // Output the constant in little endian byte order. for (unsigned i = 0; i != Size; ++i) { - EmitByte(Val & 255, OS); + EmitByte(Val & 255, CurByte, OS); Val >>= 8; } } void EmitDisplacementField(const MCOperand &Disp, int64_t Adj, bool IsPCRel, - raw_ostream &OS) const; + unsigned &CurByte, raw_ostream &OS) const; inline static unsigned char ModRMByte(unsigned Mod, unsigned RegOpcode, unsigned RM) { @@ -78,20 +80,20 @@ public: } void EmitRegModRMByte(const MCOperand &ModRMReg, unsigned RegOpcodeFld, - raw_ostream &OS) const { - EmitByte(ModRMByte(3, RegOpcodeFld, GetX86RegNum(ModRMReg)), OS); + unsigned &CurByte, raw_ostream &OS) const { + EmitByte(ModRMByte(3, RegOpcodeFld, GetX86RegNum(ModRMReg)), CurByte, OS); } void EmitSIBByte(unsigned SS, unsigned Index, unsigned Base, - raw_ostream &OS) const { - // SIB byte is in the same format as the ModRMByte... - EmitByte(ModRMByte(SS, Index, Base), OS); + unsigned &CurByte, raw_ostream &OS) const { + // SIB byte is in the same format as the ModRMByte. + EmitByte(ModRMByte(SS, Index, Base), CurByte, OS); } void EmitMemModRMByte(const MCInst &MI, unsigned Op, unsigned RegOpcodeField, intptr_t PCAdj, - raw_ostream &OS) const; + unsigned &CurByte, raw_ostream &OS) const; void EncodeInstruction(const MCInst &MI, raw_ostream &OS, SmallVectorImpl &Fixups) const; @@ -120,13 +122,18 @@ static bool isDisp8(int Value) { void X86MCCodeEmitter:: EmitDisplacementField(const MCOperand &DispOp, int64_t Adj, bool IsPCRel, - raw_ostream &OS) const { + unsigned &CurByte, raw_ostream &OS) const { // If this is a simple integer displacement that doesn't require a relocation, // emit it now. if (DispOp.isImm()) { - EmitConstant(DispOp.getImm(), 4, OS); + EmitConstant(DispOp.getImm(), 4, CurByte, OS); + CurByte += 4; return; } + + // Emit a symbolic constant as 4 0's and a Fixup. + EmitConstant(0, 4, CurByte, OS); + CurByte += 4; assert(0 && "Reloc not handled yet"); #if 0 @@ -159,7 +166,9 @@ EmitDisplacementField(const MCOperand &DispOp, int64_t Adj, bool IsPCRel, void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op, unsigned RegOpcodeField, - intptr_t PCAdj, raw_ostream &OS) const { + intptr_t PCAdj, + unsigned &CurByte, + raw_ostream &OS) const { const MCOperand &Disp = MI.getOperand(Op+3); const MCOperand &Base = MI.getOperand(Op); const MCOperand &Scale = MI.getOperand(Op+1); @@ -183,8 +192,8 @@ 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(Disp, PCAdj, true, OS); + EmitByte(ModRMByte(0, RegOpcodeField, 5), CurByte, OS); + EmitDisplacementField(Disp, PCAdj, true, CurByte, OS); return; } @@ -195,20 +204,20 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op, // encoding for [EBP] with no displacement means [disp32] so we handle it // by emitting a displacement of 0 below. if (Disp.isImm() && Disp.getImm() == 0 && BaseRegNo != N86::EBP) { - EmitByte(ModRMByte(0, RegOpcodeField, BaseRegNo), OS); + EmitByte(ModRMByte(0, RegOpcodeField, BaseRegNo), CurByte, OS); return; } // Otherwise, if the displacement fits in a byte, encode as [REG+disp8]. if (Disp.isImm() && isDisp8(Disp.getImm())) { - EmitByte(ModRMByte(1, RegOpcodeField, BaseRegNo), OS); - EmitConstant(Disp.getImm(), 1, OS); + EmitByte(ModRMByte(1, RegOpcodeField, BaseRegNo), CurByte, OS); + EmitConstant(Disp.getImm(), 1, CurByte, OS); return; } // Otherwise, emit the most general non-SIB encoding: [REG+disp32] - EmitByte(ModRMByte(2, RegOpcodeField, BaseRegNo), OS); - EmitDisplacementField(Disp, PCAdj, IsPCRel, OS); + EmitByte(ModRMByte(2, RegOpcodeField, BaseRegNo), CurByte, OS); + EmitDisplacementField(Disp, PCAdj, IsPCRel, CurByte, OS); return; } @@ -221,22 +230,22 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op, if (BaseReg == 0) { // If there is no base register, we emit the special case SIB byte with // MOD=0, BASE=5, to JUST get the index, scale, and displacement. - EmitByte(ModRMByte(0, RegOpcodeField, 4), OS); + EmitByte(ModRMByte(0, RegOpcodeField, 4), CurByte, OS); ForceDisp32 = true; } else if (!Disp.isImm()) { // Emit the normal disp32 encoding. - EmitByte(ModRMByte(2, RegOpcodeField, 4), OS); + EmitByte(ModRMByte(2, RegOpcodeField, 4), CurByte, OS); ForceDisp32 = true; } else if (Disp.getImm() == 0 && BaseReg != X86::EBP) { // Emit no displacement ModR/M byte - EmitByte(ModRMByte(0, RegOpcodeField, 4), OS); + EmitByte(ModRMByte(0, RegOpcodeField, 4), CurByte, OS); } else if (isDisp8(Disp.getImm())) { // Emit the disp8 encoding. - EmitByte(ModRMByte(1, RegOpcodeField, 4), OS); + EmitByte(ModRMByte(1, RegOpcodeField, 4), CurByte, OS); ForceDisp8 = true; // Make sure to force 8 bit disp if Base=EBP } else { // Emit the normal disp32 encoding. - EmitByte(ModRMByte(2, RegOpcodeField, 4), OS); + EmitByte(ModRMByte(2, RegOpcodeField, 4), CurByte, OS); } // Calculate what the SS field value should be... @@ -251,21 +260,21 @@ void X86MCCodeEmitter::EmitMemModRMByte(const MCInst &MI, unsigned Op, IndexRegNo = GetX86RegNum(IndexReg); else // Examples: [ESP+1*+4] or [scaled idx]+disp32 (MOD=0,BASE=5) IndexRegNo = 4; - EmitSIBByte(SS, IndexRegNo, 5, OS); + EmitSIBByte(SS, IndexRegNo, 5, CurByte, OS); } else { unsigned IndexRegNo; if (IndexReg.getReg()) IndexRegNo = GetX86RegNum(IndexReg); else IndexRegNo = 4; // For example [ESP+1*+4] - EmitSIBByte(SS, IndexRegNo, GetX86RegNum(Base), OS); + EmitSIBByte(SS, IndexRegNo, GetX86RegNum(Base), CurByte, OS); } // Do we need to output a displacement? if (ForceDisp8) - EmitConstant(Disp.getImm(), 1, OS); + EmitConstant(Disp.getImm(), 1, CurByte, OS); else if (ForceDisp32 || Disp.getImm() != 0) - EmitDisplacementField(Disp, PCAdj, IsPCRel, OS); + EmitDisplacementField(Disp, PCAdj, IsPCRel, CurByte, OS); } /// DetermineREXPrefix - Determine if the MCInst has to be encoded with a X86-64 @@ -373,36 +382,39 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, const TargetInstrDesc &Desc = TII.get(Opcode); unsigned TSFlags = Desc.TSFlags; + // Keep track of the current byte being emitted. + unsigned CurByte = 0; + // FIXME: We should emit the prefixes in exactly the same order as GAS does, // in order to provide diffability. // Emit the lock opcode prefix as needed. if (TSFlags & X86II::LOCK) - EmitByte(0xF0, OS); + EmitByte(0xF0, CurByte, OS); // Emit segment override opcode prefix as needed. switch (TSFlags & X86II::SegOvrMask) { default: assert(0 && "Invalid segment!"); case 0: break; // No segment override! case X86II::FS: - EmitByte(0x64, OS); + EmitByte(0x64, CurByte, OS); break; case X86II::GS: - EmitByte(0x65, OS); + EmitByte(0x65, CurByte, OS); break; } // Emit the repeat opcode prefix as needed. if ((TSFlags & X86II::Op0Mask) == X86II::REP) - EmitByte(0xF3, OS); + EmitByte(0xF3, CurByte, OS); // Emit the operand size opcode prefix as needed. if (TSFlags & X86II::OpSize) - EmitByte(0x66, OS); + EmitByte(0x66, CurByte, OS); // Emit the address size opcode prefix as needed. if (TSFlags & X86II::AdSize) - EmitByte(0x67, OS); + EmitByte(0x67, CurByte, OS); bool Need0FPrefix = false; switch (TSFlags & X86II::Op0Mask) { @@ -415,46 +427,46 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, Need0FPrefix = true; break; case X86II::TF: // F2 0F 38 - EmitByte(0xF2, OS); + EmitByte(0xF2, CurByte, OS); Need0FPrefix = true; break; case X86II::XS: // F3 0F - EmitByte(0xF3, OS); + EmitByte(0xF3, CurByte, OS); Need0FPrefix = true; break; case X86II::XD: // F2 0F - EmitByte(0xF2, OS); + EmitByte(0xF2, CurByte, OS); Need0FPrefix = true; break; - case X86II::D8: EmitByte(0xD8, OS); break; - case X86II::D9: EmitByte(0xD9, OS); break; - case X86II::DA: EmitByte(0xDA, OS); break; - case X86II::DB: EmitByte(0xDB, OS); break; - case X86II::DC: EmitByte(0xDC, OS); break; - case X86II::DD: EmitByte(0xDD, OS); break; - case X86II::DE: EmitByte(0xDE, OS); break; - case X86II::DF: EmitByte(0xDF, OS); break; + case X86II::D8: EmitByte(0xD8, CurByte, OS); break; + case X86II::D9: EmitByte(0xD9, CurByte, OS); break; + case X86II::DA: EmitByte(0xDA, CurByte, OS); break; + case X86II::DB: EmitByte(0xDB, CurByte, OS); break; + case X86II::DC: EmitByte(0xDC, CurByte, OS); break; + case X86II::DD: EmitByte(0xDD, CurByte, OS); break; + case X86II::DE: EmitByte(0xDE, CurByte, OS); break; + case X86II::DF: EmitByte(0xDF, CurByte, OS); break; } // Handle REX prefix. // FIXME: Can this come before F2 etc to simplify emission? if (Is64BitMode) { if (unsigned REX = DetermineREXPrefix(MI, TSFlags, Desc)) - EmitByte(0x40 | REX, OS); + EmitByte(0x40 | REX, CurByte, OS); } // 0x0F escape code must be emitted just before the opcode. if (Need0FPrefix) - EmitByte(0x0F, OS); + EmitByte(0x0F, CurByte, OS); // FIXME: Pull this up into previous switch if REX can be moved earlier. switch (TSFlags & X86II::Op0Mask) { case X86II::TF: // F2 0F 38 case X86II::T8: // 0F 38 - EmitByte(0x38, OS); + EmitByte(0x38, CurByte, OS); break; case X86II::TA: // 0F 3A - EmitByte(0x3A, OS); + EmitByte(0x3A, CurByte, OS); break; } @@ -474,7 +486,7 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, default: errs() << "FORM: " << (TSFlags & X86II::FormMask) << "\n"; assert(0 && "Unknown FormMask value in X86MCCodeEmitter!"); case X86II::RawFrm: { - EmitByte(BaseOpcode, OS); + EmitByte(BaseOpcode, CurByte, OS); if (CurOp == NumOps) break; @@ -484,14 +496,14 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, } case X86II::AddRegFrm: { - EmitByte(BaseOpcode + GetX86RegNum(MI.getOperand(CurOp++)),OS); + EmitByte(BaseOpcode + GetX86RegNum(MI.getOperand(CurOp++)), CurByte, OS); if (CurOp == NumOps) break; const MCOperand &MO1 = MI.getOperand(CurOp++); if (MO1.isImm()) { unsigned Size = X86II::getSizeOfImm(TSFlags); - EmitConstant(MO1.getImm(), Size, OS); + EmitConstant(MO1.getImm(), Size, CurByte, OS); break; } @@ -500,38 +512,38 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, } case X86II::MRMDestReg: - EmitByte(BaseOpcode, OS); + EmitByte(BaseOpcode, CurByte, OS); EmitRegModRMByte(MI.getOperand(CurOp), - GetX86RegNum(MI.getOperand(CurOp+1)), OS); + GetX86RegNum(MI.getOperand(CurOp+1)), CurByte, OS); CurOp += 2; if (CurOp != NumOps) EmitConstant(MI.getOperand(CurOp++).getImm(), - X86II::getSizeOfImm(TSFlags), OS); + X86II::getSizeOfImm(TSFlags), CurByte, OS); break; case X86II::MRMDestMem: - EmitByte(BaseOpcode, OS); + EmitByte(BaseOpcode, CurByte, OS); EmitMemModRMByte(MI, CurOp, GetX86RegNum(MI.getOperand(CurOp + X86AddrNumOperands)), - 0, OS); + 0, CurByte, OS); CurOp += X86AddrNumOperands + 1; if (CurOp != NumOps) EmitConstant(MI.getOperand(CurOp++).getImm(), - X86II::getSizeOfImm(TSFlags), OS); + X86II::getSizeOfImm(TSFlags), CurByte, OS); break; case X86II::MRMSrcReg: - EmitByte(BaseOpcode, OS); + EmitByte(BaseOpcode, CurByte, OS); EmitRegModRMByte(MI.getOperand(CurOp+1), GetX86RegNum(MI.getOperand(CurOp)), - OS); + CurByte, OS); CurOp += 2; if (CurOp != NumOps) EmitConstant(MI.getOperand(CurOp++).getImm(), - X86II::getSizeOfImm(TSFlags), OS); + X86II::getSizeOfImm(TSFlags), CurByte, OS); break; case X86II::MRMSrcMem: { - EmitByte(BaseOpcode, OS); + EmitByte(BaseOpcode, CurByte, OS); // FIXME: Maybe lea should have its own form? This is a horrible hack. int AddrOperands; @@ -546,11 +558,11 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, X86II::getSizeOfImm(TSFlags) : 0; EmitMemModRMByte(MI, CurOp+1, GetX86RegNum(MI.getOperand(CurOp)), - PCAdj, OS); + PCAdj, CurByte, OS); CurOp += AddrOperands + 1; if (CurOp != NumOps) EmitConstant(MI.getOperand(CurOp++).getImm(), - X86II::getSizeOfImm(TSFlags), OS); + X86II::getSizeOfImm(TSFlags), CurByte, OS); break; } @@ -558,23 +570,24 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, case X86II::MRM2r: case X86II::MRM3r: case X86II::MRM4r: case X86II::MRM5r: case X86II::MRM6r: case X86II::MRM7r: { - EmitByte(BaseOpcode, OS); + EmitByte(BaseOpcode, CurByte, OS); // Special handling of lfence, mfence, monitor, and mwait. // FIXME: This is terrible, they should get proper encoding bits in TSFlags. if (Opcode == X86::LFENCE || Opcode == X86::MFENCE || Opcode == X86::MONITOR || Opcode == X86::MWAIT) { - EmitByte(ModRMByte(3, (TSFlags & X86II::FormMask)-X86II::MRM0r, 0), OS); + EmitByte(ModRMByte(3, (TSFlags & X86II::FormMask)-X86II::MRM0r, 0), + CurByte, OS); switch (Opcode) { default: break; - case X86::MONITOR: EmitByte(0xC8, OS); break; - case X86::MWAIT: EmitByte(0xC9, OS); break; + case X86::MONITOR: EmitByte(0xC8, CurByte, OS); break; + case X86::MWAIT: EmitByte(0xC9, CurByte, OS); break; } } else { EmitRegModRMByte(MI.getOperand(CurOp++), (TSFlags & X86II::FormMask)-X86II::MRM0r, - OS); + CurByte, OS); } if (CurOp == NumOps) @@ -582,7 +595,7 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, const MCOperand &MO1 = MI.getOperand(CurOp++); if (MO1.isImm()) { - EmitConstant(MO1.getImm(), X86II::getSizeOfImm(TSFlags), OS); + EmitConstant(MO1.getImm(), X86II::getSizeOfImm(TSFlags), CurByte, OS); break; } @@ -617,9 +630,9 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, PCAdj = 4; } - EmitByte(BaseOpcode, OS); + EmitByte(BaseOpcode, CurByte, OS); EmitMemModRMByte(MI, CurOp, (TSFlags & X86II::FormMask)-X86II::MRM0m, - PCAdj, OS); + PCAdj, CurByte, OS); CurOp += X86AddrNumOperands; if (CurOp == NumOps) @@ -627,7 +640,7 @@ EncodeInstruction(const MCInst &MI, raw_ostream &OS, const MCOperand &MO = MI.getOperand(CurOp++); if (MO.isImm()) { - EmitConstant(MO.getImm(), X86II::getSizeOfImm(TSFlags), OS); + EmitConstant(MO.getImm(), X86II::getSizeOfImm(TSFlags), CurByte, OS); break; } -- 2.34.1