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[mips][mips64r6] Add b[on]vc

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Summary:
This required me to implement the disassembler for MIPS64r6 since the encodings
are ambiguous with other instructions. This in turn revealed a few
assembly/disassembly bugs which I have fixed.

* da[ht]i only take two operands according to the spec, not three.
* DecodeBranchTarget2[16] correctly handles wider immediates than simm16
  * Also made non-functional change to DecodeBranchTarget and
    DecodeBranchTargetMM to keep implementation style consistent between
    them.
* Difficult encodings are handled by a custom decode method on the most
  general encoding in the group. This method will convert the MCInst to a
  different opcode if necessary.

DecodeBranchTarget is not currently the inverse of getBranchTargetOpValue
so disassembling some branch instructions emit incorrect output. This seems
to affect branches with delay slots on all MIPS ISA's. I've left this bug
for now and temporarily removed the check for the immediate on
bc[12]eqz/bc[12]nez in the MIPS32r6/MIPS64r6 tests.

jialc and jic crash the disassembler for some reason. I've left these
instructions commented out for the moment.

Depends on D3760

Reviewers: jkolek, zoran.jovanovic, vmedic

Reviewed By: vmedic

Differential Revision: http://reviews.llvm.org/D3761

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209415 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Daniel Sanders
2014-05-22 11:23:21 +00:00
parent 2447dcc2e8
commit c96096cc0f
10 changed files with 681 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

253
lib/Target/Mips/Disassembler/MipsDisassembler.cpp
View File

@@ -63,6 +63,10 @@ public:
IsMicroMips = STI.getFeatureBits() & Mips::FeatureMicroMips;
}
bool isMips32r6() const {
return STI.getFeatureBits() & Mips::FeatureMips32r6;
}
/// getInstruction - See MCDisassembler.
DecodeStatus getInstruction(MCInst &instr,
uint64_t &size,
@@ -286,6 +290,32 @@ static DecodeStatus DecodeSimm19Lsl2(MCInst &Inst, unsigned Insn,
template <typename InsnType>
static DecodeStatus DecodeINSVE_DF(MCInst &MI, InsnType insn, uint64_t Address,
const void *Decoder);
template <typename InsnType>
static DecodeStatus
DecodeAddiGroupBranch(MCInst &MI, InsnType insn, uint64_t Address,
const void *Decoder);
template <typename InsnType>
static DecodeStatus
DecodeDaddiGroupBranch(MCInst &MI, InsnType insn, uint64_t Address,
const void *Decoder);
template <typename InsnType>
static DecodeStatus
DecodeBlezlGroupBranch(MCInst &MI, InsnType insn, uint64_t Address,
const void *Decoder);
template <typename InsnType>
static DecodeStatus
DecodeBgtzlGroupBranch(MCInst &MI, InsnType insn, uint64_t Address,
const void *Decoder);
template <typename InsnType>
static DecodeStatus
DecodeBgtzGroupBranch(MCInst &MI, InsnType insn, uint64_t Address,
const void *Decoder);
namespace llvm {
extern Target TheMipselTarget, TheMipsTarget, TheMips64Target,
TheMips64elTarget;
@@ -333,6 +363,12 @@ extern "C" void LLVMInitializeMipsDisassembler() {
#include "MipsGenDisassemblerTables.inc"
static unsigned getReg(const void *D, unsigned RC, unsigned RegNo) {
const MipsDisassemblerBase *Dis = static_cast<const MipsDisassemblerBase*>(D);
const MCRegisterInfo *RegInfo = Dis->getContext().getRegisterInfo();
return *(RegInfo->getRegClass(RC).begin() + RegNo);
}
template <typename InsnType>
static DecodeStatus DecodeINSVE_DF(MCInst &MI, InsnType insn, uint64_t Address,
const void *Decoder) {
@@ -379,6 +415,202 @@ static DecodeStatus DecodeINSVE_DF(MCInst &MI, InsnType insn, uint64_t Address,
return MCDisassembler::Success;
}
template <typename InsnType>
static DecodeStatus DecodeAddiGroupBranch(MCInst &MI, InsnType insn,
uint64_t Address,
const void *Decoder) {
// If we are called then we can assume that MIPS32r6/MIPS64r6 is enabled
// (otherwise we would have matched the ADDI instruction from the earlier
// ISA's instead).
//
// We have:
// 0b001000 sssss ttttt iiiiiiiiiiiiiiii
// BOVC if rs >= rt
// BEQZALC if rs == 0 && rt != 0
// BEQC if rs < rt && rs != 0
InsnType Rs = fieldFromInstruction(insn, 21, 5);
InsnType Rt = fieldFromInstruction(insn, 16, 5);
InsnType Imm = SignExtend64(fieldFromInstruction(insn, 0, 16), 16) << 2;
bool HasRs = false;
if (Rs >= Rt) {
MI.setOpcode(Mips::BOVC);
HasRs = true;
} else if (Rs != 0 && Rs < Rt) {
MI.setOpcode(Mips::BEQC);
HasRs = true;
} else
MI.setOpcode(Mips::BEQZALC);
if (HasRs)
MI.addOperand(MCOperand::CreateReg(getReg(Decoder, Mips::GPR32RegClassID,
Rs)));
MI.addOperand(MCOperand::CreateReg(getReg(Decoder, Mips::GPR32RegClassID,
Rt)));
MI.addOperand(MCOperand::CreateImm(Imm));
return MCDisassembler::Success;
}
template <typename InsnType>
static DecodeStatus DecodeDaddiGroupBranch(MCInst &MI, InsnType insn,
uint64_t Address,
const void *Decoder) {
// If we are called then we can assume that MIPS32r6/MIPS64r6 is enabled
// (otherwise we would have matched the ADDI instruction from the earlier
// ISA's instead).
//
// We have:
// 0b011000 sssss ttttt iiiiiiiiiiiiiiii
// BNVC if rs >= rt
// BNEZALC if rs == 0 && rt != 0
// BNEC if rs < rt && rs != 0
InsnType Rs = fieldFromInstruction(insn, 21, 5);
InsnType Rt = fieldFromInstruction(insn, 16, 5);
InsnType Imm = SignExtend64(fieldFromInstruction(insn, 0, 16), 16) << 2;
bool HasRs = false;
if (Rs >= Rt) {
MI.setOpcode(Mips::BNVC);
HasRs = true;
} else if (Rs != 0 && Rs < Rt) {
MI.setOpcode(Mips::BNEC);
HasRs = true;
} else
MI.setOpcode(Mips::BNEZALC);
if (HasRs)
MI.addOperand(MCOperand::CreateReg(getReg(Decoder, Mips::GPR32RegClassID,
Rs)));
MI.addOperand(MCOperand::CreateReg(getReg(Decoder, Mips::GPR32RegClassID,
Rt)));
MI.addOperand(MCOperand::CreateImm(Imm));
return MCDisassembler::Success;
}
template <typename InsnType>
static DecodeStatus DecodeBlezlGroupBranch(MCInst &MI, InsnType insn,
uint64_t Address,
const void *Decoder) {
// If we are called then we can assume that MIPS32r6/MIPS64r6 is enabled
// (otherwise we would have matched the BLEZL instruction from the earlier
// ISA's instead).
//
// We have:
// 0b010110 sssss ttttt iiiiiiiiiiiiiiii
// Invalid if rs == 0
// BLEZC if rs == 0 && rt != 0
// BGEZC if rs == rt && rt != 0
// BGEC if rs != rt && rs != 0 && rt != 0
InsnType Rs = fieldFromInstruction(insn, 21, 5);
InsnType Rt = fieldFromInstruction(insn, 16, 5);
InsnType Imm = SignExtend64(fieldFromInstruction(insn, 0, 16), 16) << 2;
if (Rt == 0)
return MCDisassembler::Fail;
else if (Rs == 0)
MI.setOpcode(Mips::BLEZC);
else if (Rs == Rt)
MI.setOpcode(Mips::BGEZC);
else
return MCDisassembler::Fail; // FIXME: BGEC is not implemented yet.
MI.addOperand(MCOperand::CreateReg(getReg(Decoder, Mips::GPR32RegClassID,
Rt)));
MI.addOperand(MCOperand::CreateImm(Imm));
return MCDisassembler::Success;
}
template <typename InsnType>
static DecodeStatus DecodeBgtzlGroupBranch(MCInst &MI, InsnType insn,
uint64_t Address,
const void *Decoder) {
// If we are called then we can assume that MIPS32r6/MIPS64r6 is enabled
// (otherwise we would have matched the BGTZL instruction from the earlier
// ISA's instead).
//
// We have:
// 0b010111 sssss ttttt iiiiiiiiiiiiiiii
// Invalid if rs == 0
// BGTZC if rs == 0 && rt != 0
// BLTZC if rs == rt && rt != 0
// BLTC if rs != rt && rs != 0 && rt != 0
InsnType Rs = fieldFromInstruction(insn, 21, 5);
InsnType Rt = fieldFromInstruction(insn, 16, 5);
InsnType Imm = SignExtend64(fieldFromInstruction(insn, 0, 16), 16) << 2;
if (Rt == 0)
return MCDisassembler::Fail;
else if (Rs == 0)
MI.setOpcode(Mips::BGTZC);
else if (Rs == Rt)
MI.setOpcode(Mips::BLTZC);
else
return MCDisassembler::Fail; // FIXME: BLTC is not implemented yet.
MI.addOperand(MCOperand::CreateReg(getReg(Decoder, Mips::GPR32RegClassID,
Rt)));
MI.addOperand(MCOperand::CreateImm(Imm));
return MCDisassembler::Success;
}
template <typename InsnType>
static DecodeStatus DecodeBgtzGroupBranch(MCInst &MI, InsnType insn,
uint64_t Address,
const void *Decoder) {
// If we are called then we can assume that MIPS32r6/MIPS64r6 is enabled
// (otherwise we would have matched the BGTZ instruction from the earlier
// ISA's instead).
//
// We have:
// 0b000111 sssss ttttt iiiiiiiiiiiiiiii
// BGTZ if rt == 0
// BGTZALC if rs == 0 && rt != 0
// BLTZALC if rs != 0 && rs == rt
// BLTUC if rs != 0 && rs != rt
InsnType Rs = fieldFromInstruction(insn, 21, 5);
InsnType Rt = fieldFromInstruction(insn, 16, 5);
InsnType Imm = SignExtend64(fieldFromInstruction(insn, 0, 16), 16) << 2;
bool HasRs = false;
bool HasRt = false;
if (Rt == 0) {
MI.setOpcode(Mips::BGTZ);
HasRs = true;
} else if (Rs == 0) {
MI.setOpcode(Mips::BGTZALC);
HasRt = true;
} else if (Rs == Rt) {
MI.setOpcode(Mips::BLTZALC);
HasRs = true;
} else
return MCDisassembler::Fail; // BLTUC not implemented yet
if (HasRs)
MI.addOperand(MCOperand::CreateReg(getReg(Decoder, Mips::GPR32RegClassID,
Rs)));
if (HasRt)
MI.addOperand(MCOperand::CreateReg(getReg(Decoder, Mips::GPR32RegClassID,
Rt)));
MI.addOperand(MCOperand::CreateImm(Imm));
return MCDisassembler::Success;
}
/// readInstruction - read four bytes from the MemoryObject
/// and return 32 bit word sorted according to the given endianess
static DecodeStatus readInstruction32(const MemoryObject &region,
@@ -448,6 +680,15 @@ MipsDisassembler::getInstruction(MCInst &instr,
return MCDisassembler::Fail;
}
if (isMips32r6()) {
Result = decodeInstruction(DecoderTableMips32r6_64r632, instr, Insn,
Address, this, STI);
if (Result != MCDisassembler::Fail) {
Size = 4;
return Result;
}
}
// Calling the auto-generated decoder function.
Result = decodeInstruction(DecoderTableMips32, instr, Insn, Address,
this, STI);
@@ -491,12 +732,6 @@ Mips64Disassembler::getInstruction(MCInst &instr,
return MCDisassembler::Fail;
}
static unsigned getReg(const void *D, unsigned RC, unsigned RegNo) {
const MipsDisassemblerBase *Dis = static_cast<const MipsDisassemblerBase*>(D);
const MCRegisterInfo *RegInfo = Dis->getContext().getRegisterInfo();
return *(RegInfo->getRegClass(RC).begin() + RegNo);
}
static DecodeStatus DecodeCPU16RegsRegisterClass(MCInst &Inst,
unsigned RegNo,
uint64_t Address,
@@ -867,8 +1102,7 @@ static DecodeStatus DecodeBranchTarget(MCInst &Inst,
unsigned Offset,
uint64_t Address,
const void *Decoder) {
unsigned BranchOffset = Offset & 0xffff;
BranchOffset = SignExtend32<18>(BranchOffset << 2) + 4;
int32_t BranchOffset = (SignExtend32<16>(Offset) << 2) + 4;
Inst.addOperand(MCOperand::CreateImm(BranchOffset));
return MCDisassembler::Success;
}
@@ -907,8 +1141,7 @@ static DecodeStatus DecodeBranchTargetMM(MCInst &Inst,
unsigned Offset,
uint64_t Address,
const void *Decoder) {
unsigned BranchOffset = Offset & 0xffff;
BranchOffset = SignExtend32<18>(BranchOffset << 1);
int32_t BranchOffset = SignExtend32<16>(Offset) << 1;
Inst.addOperand(MCOperand::CreateImm(BranchOffset));
return MCDisassembler::Success;
}