[llvm] 63d9e3c - [NFC][ARM][MC] Rearrange decoder functions 2/N (#155464)
via llvm-commits
llvm-commits at lists.llvm.org
Sun Aug 31 05:20:45 PDT 2025
Author: Rahul Joshi
Date: 2025-08-31T05:20:41-07:00
New Revision: 63d9e3c114756a3b892d4352313c6dff48b6d560
URL: https://github.com/llvm/llvm-project/commit/63d9e3c114756a3b892d4352313c6dff48b6d560
DIFF: https://github.com/llvm/llvm-project/commit/63d9e3c114756a3b892d4352313c6dff48b6d560.diff
LOG: [NFC][ARM][MC] Rearrange decoder functions 2/N (#155464)
Move some of the non-static-decode functions to the end of the file.
Note: moving `ARMDisassembler::AddThumbPredicate` the same way causes
the diff to be non-trivial, so not doing that here.
Added:
Modified:
llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
Removed:
################################################################################
diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index f7a7a891dc224..4052593008027 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -1018,260 +1018,6 @@ ARMDisassembler::AddThumbPredicate(MCInst &MI) const {
return S;
}
-// Thumb VFP instructions are a special case. Because we share their
-// encodings between ARM and Thumb modes, and they are predicable in ARM
-// mode, the auto-generated decoder will give them an (incorrect)
-// predicate operand. We need to rewrite these operands based on the IT
-// context as a post-pass.
-void ARMDisassembler::UpdateThumbVFPPredicate(
- DecodeStatus &S, MCInst &MI) const {
- unsigned CC;
- CC = ITBlock.getITCC();
- if (CC == 0xF)
- CC = ARMCC::AL;
- if (ITBlock.instrInITBlock())
- ITBlock.advanceITState();
- else if (VPTBlock.instrInVPTBlock()) {
- CC = VPTBlock.getVPTPred();
- VPTBlock.advanceVPTState();
- }
-
- const MCInstrDesc &MCID = MCII->get(MI.getOpcode());
- ArrayRef<MCOperandInfo> OpInfo = MCID.operands();
- MCInst::iterator I = MI.begin();
- unsigned short NumOps = MCID.NumOperands;
- for (unsigned i = 0; i < NumOps; ++i, ++I) {
- if (OpInfo[i].isPredicate() ) {
- if (CC != ARMCC::AL && !MCID.isPredicable())
- Check(S, SoftFail);
- I->setImm(CC);
- ++I;
- if (CC == ARMCC::AL)
- I->setReg(ARM::NoRegister);
- else
- I->setReg(ARM::CPSR);
- return;
- }
- }
-}
-
-DecodeStatus ARMDisassembler::getThumbInstruction(MCInst &MI, uint64_t &Size,
- ArrayRef<uint8_t> Bytes,
- uint64_t Address,
- raw_ostream &CS) const {
- CommentStream = &CS;
-
- assert(STI.hasFeature(ARM::ModeThumb) &&
- "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
-
- // We want to read exactly 2 bytes of data.
- if (Bytes.size() < 2) {
- Size = 0;
- return MCDisassembler::Fail;
- }
-
- uint16_t Insn16 = llvm::support::endian::read<uint16_t>(
- Bytes.data(), InstructionEndianness);
- DecodeStatus Result =
- decodeInstruction(DecoderTableThumb16, MI, Insn16, Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 2;
- Check(Result, AddThumbPredicate(MI));
- return Result;
- }
-
- Result = decodeInstruction(DecoderTableThumbSBit16, MI, Insn16, Address, this,
- STI);
- if (Result) {
- Size = 2;
- bool InITBlock = ITBlock.instrInITBlock();
- Check(Result, AddThumbPredicate(MI));
- AddThumb1SBit(MI, InITBlock);
- return Result;
- }
-
- Result =
- decodeInstruction(DecoderTableThumb216, MI, Insn16, Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 2;
-
- // Nested IT blocks are UNPREDICTABLE. Must be checked before we add
- // the Thumb predicate.
- if (MI.getOpcode() == ARM::t2IT && ITBlock.instrInITBlock())
- Result = MCDisassembler::SoftFail;
-
- Check(Result, AddThumbPredicate(MI));
-
- // If we find an IT instruction, we need to parse its condition
- // code and mask operands so that we can apply them correctly
- // to the subsequent instructions.
- if (MI.getOpcode() == ARM::t2IT) {
- unsigned Firstcond = MI.getOperand(0).getImm();
- unsigned Mask = MI.getOperand(1).getImm();
- ITBlock.setITState(Firstcond, Mask);
-
- // An IT instruction that would give a 'NV' predicate is unpredictable.
- if (Firstcond == ARMCC::AL && !isPowerOf2_32(Mask))
- CS << "unpredictable IT predicate sequence";
- }
-
- return Result;
- }
-
- // We want to read exactly 4 bytes of data.
- if (Bytes.size() < 4) {
- Size = 0;
- return MCDisassembler::Fail;
- }
-
- uint32_t Insn32 =
- (uint32_t(Insn16) << 16) | llvm::support::endian::read<uint16_t>(
- Bytes.data() + 2, InstructionEndianness);
-
- Result =
- decodeInstruction(DecoderTableMVE32, MI, Insn32, Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
-
- // Nested VPT blocks are UNPREDICTABLE. Must be checked before we add
- // the VPT predicate.
- if (isVPTOpcode(MI.getOpcode()) && VPTBlock.instrInVPTBlock())
- Result = MCDisassembler::SoftFail;
-
- Check(Result, AddThumbPredicate(MI));
-
- if (isVPTOpcode(MI.getOpcode())) {
- unsigned Mask = MI.getOperand(0).getImm();
- VPTBlock.setVPTState(Mask);
- }
-
- return Result;
- }
-
- Result =
- decodeInstruction(DecoderTableThumb32, MI, Insn32, Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- bool InITBlock = ITBlock.instrInITBlock();
- Check(Result, AddThumbPredicate(MI));
- AddThumb1SBit(MI, InITBlock);
- return Result;
- }
-
- Result =
- decodeInstruction(DecoderTableThumb232, MI, Insn32, Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- Check(Result, AddThumbPredicate(MI));
- return checkDecodedInstruction(MI, Size, Address, CS, Insn32, Result);
- }
-
- if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
- Result =
- decodeInstruction(DecoderTableVFP32, MI, Insn32, Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- UpdateThumbVFPPredicate(Result, MI);
- return Result;
- }
- }
-
- Result =
- decodeInstruction(DecoderTableVFPV832, MI, Insn32, Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- return Result;
- }
-
- if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
- Result = decodeInstruction(DecoderTableNEONDup32, MI, Insn32, Address, this,
- STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- Check(Result, AddThumbPredicate(MI));
- return Result;
- }
- }
-
- if (fieldFromInstruction(Insn32, 24, 8) == 0xF9) {
- uint32_t NEONLdStInsn = Insn32;
- NEONLdStInsn &= 0xF0FFFFFF;
- NEONLdStInsn |= 0x04000000;
- Result = decodeInstruction(DecoderTableNEONLoadStore32, MI, NEONLdStInsn,
- Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- Check(Result, AddThumbPredicate(MI));
- return Result;
- }
- }
-
- if (fieldFromInstruction(Insn32, 24, 4) == 0xF) {
- uint32_t NEONDataInsn = Insn32;
- NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
- NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
- NEONDataInsn |= 0x12000000; // Set bits 28 and 25
- Result = decodeInstruction(DecoderTableNEONData32, MI, NEONDataInsn,
- Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- Check(Result, AddThumbPredicate(MI));
- return Result;
- }
-
- uint32_t NEONCryptoInsn = Insn32;
- NEONCryptoInsn &= 0xF0FFFFFF; // Clear bits 27-24
- NEONCryptoInsn |= (NEONCryptoInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
- NEONCryptoInsn |= 0x12000000; // Set bits 28 and 25
- Result = decodeInstruction(DecoderTablev8Crypto32, MI, NEONCryptoInsn,
- Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- return Result;
- }
-
- uint32_t NEONv8Insn = Insn32;
- NEONv8Insn &= 0xF3FFFFFF; // Clear bits 27-26
- Result = decodeInstruction(DecoderTablev8NEON32, MI, NEONv8Insn, Address,
- this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- return Result;
- }
- }
-
- uint32_t Coproc = fieldFromInstruction(Insn32, 8, 4);
- const uint8_t *DecoderTable = ARM::isCDECoproc(Coproc, STI)
- ? DecoderTableThumb2CDE32
- : DecoderTableThumb2CoProc32;
- Result =
- decodeInstruction(DecoderTable, MI, Insn32, Address, this, STI);
- if (Result != MCDisassembler::Fail) {
- Size = 4;
- Check(Result, AddThumbPredicate(MI));
- return Result;
- }
-
- // Advance IT state to prevent next instruction inheriting
- // the wrong IT state.
- if (ITBlock.instrInITBlock())
- ITBlock.advanceITState();
- Size = 0;
- return MCDisassembler::Fail;
-}
-
-extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
-LLVMInitializeARMDisassembler() {
- TargetRegistry::RegisterMCDisassembler(getTheARMLETarget(),
- createARMDisassembler);
- TargetRegistry::RegisterMCDisassembler(getTheARMBETarget(),
- createARMDisassembler);
- TargetRegistry::RegisterMCDisassembler(getTheThumbLETarget(),
- createARMDisassembler);
- TargetRegistry::RegisterMCDisassembler(getTheThumbBETarget(),
- createARMDisassembler);
-}
-
static const uint16_t GPRDecoderTable[] = {
ARM::R0, ARM::R1, ARM::R2, ARM::R3,
ARM::R4, ARM::R5, ARM::R6, ARM::R7,
@@ -7069,3 +6815,257 @@ static DecodeStatus DecodeLazyLoadStoreMul(MCInst &Inst, unsigned Insn,
return S;
}
+
+// Thumb VFP instructions are a special case. Because we share their
+// encodings between ARM and Thumb modes, and they are predicable in ARM
+// mode, the auto-generated decoder will give them an (incorrect)
+// predicate operand. We need to rewrite these operands based on the IT
+// context as a post-pass.
+void ARMDisassembler::UpdateThumbVFPPredicate(
+ DecodeStatus &S, MCInst &MI) const {
+ unsigned CC;
+ CC = ITBlock.getITCC();
+ if (CC == 0xF)
+ CC = ARMCC::AL;
+ if (ITBlock.instrInITBlock())
+ ITBlock.advanceITState();
+ else if (VPTBlock.instrInVPTBlock()) {
+ CC = VPTBlock.getVPTPred();
+ VPTBlock.advanceVPTState();
+ }
+
+ const MCInstrDesc &MCID = MCII->get(MI.getOpcode());
+ ArrayRef<MCOperandInfo> OpInfo = MCID.operands();
+ MCInst::iterator I = MI.begin();
+ unsigned short NumOps = MCID.NumOperands;
+ for (unsigned i = 0; i < NumOps; ++i, ++I) {
+ if (OpInfo[i].isPredicate() ) {
+ if (CC != ARMCC::AL && !MCID.isPredicable())
+ Check(S, SoftFail);
+ I->setImm(CC);
+ ++I;
+ if (CC == ARMCC::AL)
+ I->setReg(ARM::NoRegister);
+ else
+ I->setReg(ARM::CPSR);
+ return;
+ }
+ }
+}
+
+DecodeStatus ARMDisassembler::getThumbInstruction(MCInst &MI, uint64_t &Size,
+ ArrayRef<uint8_t> Bytes,
+ uint64_t Address,
+ raw_ostream &CS) const {
+ CommentStream = &CS;
+
+ assert(STI.hasFeature(ARM::ModeThumb) &&
+ "Asked to disassemble in Thumb mode but Subtarget is in ARM mode!");
+
+ // We want to read exactly 2 bytes of data.
+ if (Bytes.size() < 2) {
+ Size = 0;
+ return MCDisassembler::Fail;
+ }
+
+ uint16_t Insn16 = llvm::support::endian::read<uint16_t>(
+ Bytes.data(), InstructionEndianness);
+ DecodeStatus Result =
+ decodeInstruction(DecoderTableThumb16, MI, Insn16, Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 2;
+ Check(Result, AddThumbPredicate(MI));
+ return Result;
+ }
+
+ Result = decodeInstruction(DecoderTableThumbSBit16, MI, Insn16, Address, this,
+ STI);
+ if (Result) {
+ Size = 2;
+ bool InITBlock = ITBlock.instrInITBlock();
+ Check(Result, AddThumbPredicate(MI));
+ AddThumb1SBit(MI, InITBlock);
+ return Result;
+ }
+
+ Result =
+ decodeInstruction(DecoderTableThumb216, MI, Insn16, Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 2;
+
+ // Nested IT blocks are UNPREDICTABLE. Must be checked before we add
+ // the Thumb predicate.
+ if (MI.getOpcode() == ARM::t2IT && ITBlock.instrInITBlock())
+ Result = MCDisassembler::SoftFail;
+
+ Check(Result, AddThumbPredicate(MI));
+
+ // If we find an IT instruction, we need to parse its condition
+ // code and mask operands so that we can apply them correctly
+ // to the subsequent instructions.
+ if (MI.getOpcode() == ARM::t2IT) {
+ unsigned Firstcond = MI.getOperand(0).getImm();
+ unsigned Mask = MI.getOperand(1).getImm();
+ ITBlock.setITState(Firstcond, Mask);
+
+ // An IT instruction that would give a 'NV' predicate is unpredictable.
+ if (Firstcond == ARMCC::AL && !isPowerOf2_32(Mask))
+ CS << "unpredictable IT predicate sequence";
+ }
+
+ return Result;
+ }
+
+ // We want to read exactly 4 bytes of data.
+ if (Bytes.size() < 4) {
+ Size = 0;
+ return MCDisassembler::Fail;
+ }
+
+ uint32_t Insn32 =
+ (uint32_t(Insn16) << 16) | llvm::support::endian::read<uint16_t>(
+ Bytes.data() + 2, InstructionEndianness);
+
+ Result =
+ decodeInstruction(DecoderTableMVE32, MI, Insn32, Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+
+ // Nested VPT blocks are UNPREDICTABLE. Must be checked before we add
+ // the VPT predicate.
+ if (isVPTOpcode(MI.getOpcode()) && VPTBlock.instrInVPTBlock())
+ Result = MCDisassembler::SoftFail;
+
+ Check(Result, AddThumbPredicate(MI));
+
+ if (isVPTOpcode(MI.getOpcode())) {
+ unsigned Mask = MI.getOperand(0).getImm();
+ VPTBlock.setVPTState(Mask);
+ }
+
+ return Result;
+ }
+
+ Result =
+ decodeInstruction(DecoderTableThumb32, MI, Insn32, Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ bool InITBlock = ITBlock.instrInITBlock();
+ Check(Result, AddThumbPredicate(MI));
+ AddThumb1SBit(MI, InITBlock);
+ return Result;
+ }
+
+ Result =
+ decodeInstruction(DecoderTableThumb232, MI, Insn32, Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ Check(Result, AddThumbPredicate(MI));
+ return checkDecodedInstruction(MI, Size, Address, CS, Insn32, Result);
+ }
+
+ if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
+ Result =
+ decodeInstruction(DecoderTableVFP32, MI, Insn32, Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ UpdateThumbVFPPredicate(Result, MI);
+ return Result;
+ }
+ }
+
+ Result =
+ decodeInstruction(DecoderTableVFPV832, MI, Insn32, Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ return Result;
+ }
+
+ if (fieldFromInstruction(Insn32, 28, 4) == 0xE) {
+ Result = decodeInstruction(DecoderTableNEONDup32, MI, Insn32, Address, this,
+ STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ Check(Result, AddThumbPredicate(MI));
+ return Result;
+ }
+ }
+
+ if (fieldFromInstruction(Insn32, 24, 8) == 0xF9) {
+ uint32_t NEONLdStInsn = Insn32;
+ NEONLdStInsn &= 0xF0FFFFFF;
+ NEONLdStInsn |= 0x04000000;
+ Result = decodeInstruction(DecoderTableNEONLoadStore32, MI, NEONLdStInsn,
+ Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ Check(Result, AddThumbPredicate(MI));
+ return Result;
+ }
+ }
+
+ if (fieldFromInstruction(Insn32, 24, 4) == 0xF) {
+ uint32_t NEONDataInsn = Insn32;
+ NEONDataInsn &= 0xF0FFFFFF; // Clear bits 27-24
+ NEONDataInsn |= (NEONDataInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
+ NEONDataInsn |= 0x12000000; // Set bits 28 and 25
+ Result = decodeInstruction(DecoderTableNEONData32, MI, NEONDataInsn,
+ Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ Check(Result, AddThumbPredicate(MI));
+ return Result;
+ }
+
+ uint32_t NEONCryptoInsn = Insn32;
+ NEONCryptoInsn &= 0xF0FFFFFF; // Clear bits 27-24
+ NEONCryptoInsn |= (NEONCryptoInsn & 0x10000000) >> 4; // Move bit 28 to bit 24
+ NEONCryptoInsn |= 0x12000000; // Set bits 28 and 25
+ Result = decodeInstruction(DecoderTablev8Crypto32, MI, NEONCryptoInsn,
+ Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ return Result;
+ }
+
+ uint32_t NEONv8Insn = Insn32;
+ NEONv8Insn &= 0xF3FFFFFF; // Clear bits 27-26
+ Result = decodeInstruction(DecoderTablev8NEON32, MI, NEONv8Insn, Address,
+ this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ return Result;
+ }
+ }
+
+ uint32_t Coproc = fieldFromInstruction(Insn32, 8, 4);
+ const uint8_t *DecoderTable = ARM::isCDECoproc(Coproc, STI)
+ ? DecoderTableThumb2CDE32
+ : DecoderTableThumb2CoProc32;
+ Result =
+ decodeInstruction(DecoderTable, MI, Insn32, Address, this, STI);
+ if (Result != MCDisassembler::Fail) {
+ Size = 4;
+ Check(Result, AddThumbPredicate(MI));
+ return Result;
+ }
+
+ // Advance IT state to prevent next instruction inheriting
+ // the wrong IT state.
+ if (ITBlock.instrInITBlock())
+ ITBlock.advanceITState();
+ Size = 0;
+ return MCDisassembler::Fail;
+}
+
+extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
+LLVMInitializeARMDisassembler() {
+ TargetRegistry::RegisterMCDisassembler(getTheARMLETarget(),
+ createARMDisassembler);
+ TargetRegistry::RegisterMCDisassembler(getTheARMBETarget(),
+ createARMDisassembler);
+ TargetRegistry::RegisterMCDisassembler(getTheThumbLETarget(),
+ createARMDisassembler);
+ TargetRegistry::RegisterMCDisassembler(getTheThumbBETarget(),
+ createARMDisassembler);
+}
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