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[RISCV][NFC] Simplify decoding code of disassembler
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The decoding parts are reduplicative, we add a macro to simplify
the code.

Reviewed By: craig.topper, kito-cheng

Differential Revision: https://reviews.llvm.org/D151309
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@pcwang-thead
pcwang-thead committed May 25, 2023
1 parent cc2d061 commit 92723d5
Showing 1 changed file with 72 additions and 146 deletions.
218 changes: 72 additions & 146 deletions llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -490,6 +490,27 @@ DecodeStatus RISCVDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
uint32_t Insn;
DecodeStatus Result;

#define TRY_TO_DECODE_WITH_ADDITIONAL_OPERATION(FEATURE_CHECKS, DECODER_TABLE, \
DESC, ADDITIONAL_OPERATION) \
do { \
if (FEATURE_CHECKS) { \
LLVM_DEBUG(dbgs() << "Trying " DESC ":\n"); \
Result = decodeInstruction(DECODER_TABLE, MI, Insn, Address, this, STI); \
if (Result != MCDisassembler::Fail) { \
ADDITIONAL_OPERATION; \
return Result; \
} \
} \
} while (false)
#define TRY_TO_DECODE_AND_ADD_SP(FEATURE_CHECKS, DECODER_TABLE, DESC) \
TRY_TO_DECODE_WITH_ADDITIONAL_OPERATION(FEATURE_CHECKS, DECODER_TABLE, DESC, \
addSPOperands(MI))
#define TRY_TO_DECODE(FEATURE_CHECKS, DECODER_TABLE, DESC) \
TRY_TO_DECODE_WITH_ADDITIONAL_OPERATION(FEATURE_CHECKS, DECODER_TABLE, DESC, \
(void)nullptr)
#define TRY_TO_DECODE_FEATURE(FEATURE, DECODER_TABLE, DESC) \
TRY_TO_DECODE(STI.hasFeature(FEATURE), DECODER_TABLE, DESC)

// It's a 32 bit instruction if bit 0 and 1 are 1.
if ((Bytes[0] & 0x3) == 0x3) {
if (Bytes.size() < 4) {
Expand All @@ -500,116 +521,46 @@ DecodeStatus RISCVDisassembler::getInstruction(MCInst &MI, uint64_t &Size,

Insn = support::endian::read32le(Bytes.data());

if (STI.hasFeature(RISCV::FeatureStdExtZdinx) &&
!STI.hasFeature(RISCV::Feature64Bit)) {
LLVM_DEBUG(dbgs() << "Trying RV32Zdinx table (Double in Integer and"
"rv32)\n");
Result = decodeInstruction(DecoderTableRV32Zdinx32, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureStdExtZfinx)) {
LLVM_DEBUG(dbgs() << "Trying RVZfinx table (Float in Integer):\n");
Result = decodeInstruction(DecoderTableRVZfinx32, MI, Insn, Address, this,
STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXVentanaCondOps)) {
LLVM_DEBUG(dbgs() << "Trying Ventana custom opcode table:\n");
Result = decodeInstruction(DecoderTableVentana32, MI, Insn, Address, this,
STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadBa)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadBa custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadBa32, MI, Insn, Address, this,
STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadBb)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadBb custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadBb32, MI, Insn, Address, this,
STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadBs)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadBs custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadBs32, MI, Insn, Address, this,
STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadCondMov)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadCondMov custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadCondMov32, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadCmo)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadCmo custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadCmo32, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadFMemIdx)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadFMemIdx custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadFMemIdx32, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadMac)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadMac custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadMac32, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadMemIdx)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadMemIdx custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadMemIdx32, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadMemPair)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadMemPair custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadMemPair32, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadSync)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadSync custom opcode table:\n");
Result = decodeInstruction(DecoderTableTHeadSync32, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXTHeadVdot)) {
LLVM_DEBUG(dbgs() << "Trying XTHeadVdot custom opcode table:\n");
Result =
decodeInstruction(DecoderTableTHeadV32, MI, Insn, Address, this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureVendorXSfvcp)) {
LLVM_DEBUG(dbgs() << "Trying SiFive VCIX custom opcode table:\n");
Result = decodeInstruction(DecoderTableXSfvcp32, MI, Insn, Address, this,
STI);
if (Result != MCDisassembler::Fail)
return Result;
}
TRY_TO_DECODE(STI.hasFeature(RISCV::FeatureStdExtZdinx) &&
!STI.hasFeature(RISCV::Feature64Bit),
DecoderTableRV32Zdinx32,
"RV32Zdinx table (Double in Integer and rv32)");
TRY_TO_DECODE_FEATURE(RISCV::FeatureStdExtZfinx, DecoderTableRVZfinx32,
"RVZfinx table (Float in Integer)");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXVentanaCondOps,
DecoderTableVentana32, "Ventana custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadBa, DecoderTableTHeadBa32,
"XTHeadBa custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadBb, DecoderTableTHeadBb32,
"XTHeadBb custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadBs, DecoderTableTHeadBs32,
"XTHeadBs custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadCondMov,
DecoderTableTHeadCondMov32,
"XTHeadCondMov custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadCmo, DecoderTableTHeadCmo32,
"XTHeadCmo custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadFMemIdx,
DecoderTableTHeadFMemIdx32,
"XTHeadFMemIdx custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadMac, DecoderTableTHeadMac32,
"XTHeadMac custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadMemIdx,
DecoderTableTHeadMemIdx32,
"XTHeadMemIdx custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadMemPair,
DecoderTableTHeadMemPair32,
"XTHeadMemPair custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadSync,
DecoderTableTHeadSync32,
"XTHeadSync custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXTHeadVdot, DecoderTableTHeadV32,
"XTHeadVdot custom opcode table");
TRY_TO_DECODE_FEATURE(RISCV::FeatureVendorXSfvcp, DecoderTableXSfvcp32,
"SiFive VCIX custom opcode table");
TRY_TO_DECODE(true, DecoderTable32, "RISCV32 table");

LLVM_DEBUG(dbgs() << "Trying RISCV32 table :\n");
return decodeInstruction(DecoderTable32, MI, Insn, Address, this, STI);
return MCDisassembler::Fail;
}

if (Bytes.size() < 2) {
Expand All @@ -619,41 +570,16 @@ DecodeStatus RISCVDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
Size = 2;

Insn = support::endian::read16le(Bytes.data());

if (!STI.hasFeature(RISCV::Feature64Bit)) {
LLVM_DEBUG(
dbgs() << "Trying RISCV32Only_16 table (16-bit Instruction):\n");
// Calling the auto-generated decoder function.
Result = decodeInstruction(DecoderTableRISCV32Only_16, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail) {
addSPOperands(MI);
return Result;
}
}
if (STI.hasFeature(RISCV::FeatureStdExtZcmt)) {
LLVM_DEBUG(
dbgs() << "Trying Zcmt table (16-bit Table Jump Instructions):\n");
Result = decodeInstruction(DecoderTableRVZcmt16, MI, Insn, Address,
this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}
if (STI.hasFeature(RISCV::FeatureStdExtZcmp)) {
LLVM_DEBUG(
dbgs()
<< "Trying Zcmp table (16-bit Push/Pop & Double Move Instructions):\n");
Result =
decodeInstruction(DecoderTableRVZcmp16, MI, Insn, Address, this, STI);
if (Result != MCDisassembler::Fail)
return Result;
}

LLVM_DEBUG(dbgs() << "Trying RISCV_C table (16-bit Instruction):\n");
// Calling the auto-generated decoder function.
Result = decodeInstruction(DecoderTable16, MI, Insn, Address, this, STI);
if (Result != MCDisassembler::Fail)
addSPOperands(MI);

return Result;
TRY_TO_DECODE_AND_ADD_SP(!STI.hasFeature(RISCV::Feature64Bit),
DecoderTableRISCV32Only_16,
"RISCV32Only_16 table (16-bit Instruction)");
TRY_TO_DECODE_FEATURE(RISCV::FeatureStdExtZcmt, DecoderTableRVZcmt16,
"Zcmt table (16-bit Table Jump Instructions)");
TRY_TO_DECODE_FEATURE(
RISCV::FeatureStdExtZcmp, DecoderTableRVZcmp16,
"Zcmp table (16-bit Push/Pop & Double Move Instructions)");
TRY_TO_DECODE_AND_ADD_SP(true, DecoderTable16,
"RISCV_C table (16-bit Instruction)");

return MCDisassembler::Fail;
}

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