Author: Rahul Joshi Date: 2025-04-16T13:15:51-07:00 New Revision: 24b0bd6a97ed115c7530f0538eed9b9ef2b581f9
URL: https://github.com/llvm/llvm-project/commit/24b0bd6a97ed115c7530f0538eed9b9ef2b581f9 DIFF: https://github.com/llvm/llvm-project/commit/24b0bd6a97ed115c7530f0538eed9b9ef2b581f9.diff LOG: Revert "[LLVM][TableGen] Parameterize NumToSkip in DecoderEmitter (#135882)" This reverts commit 598ec8ce2d1e5e20b45c56de8972f58a0caeb697. Added: Modified: llvm/lib/Target/AArch64/CMakeLists.txt llvm/test/TableGen/VarLenDecoder.td llvm/test/TableGen/trydecode-emission.td llvm/test/TableGen/trydecode-emission2.td llvm/test/TableGen/trydecode-emission3.td llvm/test/TableGen/trydecode-emission4.td llvm/utils/TableGen/DecoderEmitter.cpp Removed: ################################################################################ diff --git a/llvm/lib/Target/AArch64/CMakeLists.txt b/llvm/lib/Target/AArch64/CMakeLists.txt index ba1d1605ec104..2300e479bc110 100644 --- a/llvm/lib/Target/AArch64/CMakeLists.txt +++ b/llvm/lib/Target/AArch64/CMakeLists.txt @@ -7,7 +7,7 @@ tablegen(LLVM AArch64GenAsmWriter.inc -gen-asm-writer) tablegen(LLVM AArch64GenAsmWriter1.inc -gen-asm-writer -asmwriternum=1) tablegen(LLVM AArch64GenCallingConv.inc -gen-callingconv) tablegen(LLVM AArch64GenDAGISel.inc -gen-dag-isel) -tablegen(LLVM AArch64GenDisassemblerTables.inc -gen-disassembler --num-to-skip-size=3) +tablegen(LLVM AArch64GenDisassemblerTables.inc -gen-disassembler) tablegen(LLVM AArch64GenFastISel.inc -gen-fast-isel) tablegen(LLVM AArch64GenGlobalISel.inc -gen-global-isel) tablegen(LLVM AArch64GenO0PreLegalizeGICombiner.inc -gen-global-isel-combiner diff --git a/llvm/test/TableGen/VarLenDecoder.td b/llvm/test/TableGen/VarLenDecoder.td index b77702ff7c5c1..5cf0bf8911859 100644 --- a/llvm/test/TableGen/VarLenDecoder.td +++ b/llvm/test/TableGen/VarLenDecoder.td @@ -47,9 +47,9 @@ def FOO32 : MyVarInst<MemOp32> { } // CHECK: MCD::OPC_ExtractField, 3, 5, // Inst{7-3} ... -// CHECK-NEXT: MCD::OPC_FilterValue, 8, 4, 0, // Skip to: 11 +// CHECK-NEXT: MCD::OPC_FilterValue, 8, 4, 0, 0, // Skip to: 12 // CHECK-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 0, // Opcode: FOO16 -// CHECK-NEXT: MCD::OPC_FilterValue, 9, 4, 0, // Skip to: 19 +// CHECK-NEXT: MCD::OPC_FilterValue, 9, 4, 0, 0, // Skip to: 21 // CHECK-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: FOO32 // CHECK-NEXT: MCD::OPC_Fail, diff --git a/llvm/test/TableGen/trydecode-emission.td b/llvm/test/TableGen/trydecode-emission.td index 2b4239f4fbe65..20d2446eeac7f 100644 --- a/llvm/test/TableGen/trydecode-emission.td +++ b/llvm/test/TableGen/trydecode-emission.td @@ -34,10 +34,10 @@ def InstB : TestInstruction { } // CHECK: /* 0 */ MCD::OPC_ExtractField, 4, 4, // Inst{7-4} ... -// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 16, 0, // Skip to: 23 -// CHECK-NEXT: /* 7 */ MCD::OPC_CheckField, 2, 2, 0, 6, 0, // Skip to: 19 -// CHECK-NEXT: /* 13 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, // Opcode: InstB, skip to: 19 -// CHECK-NEXT: /* 19 */ MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: InstA -// CHECK-NEXT: /* 23 */ MCD::OPC_Fail, +// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 18, 0, 0, // Skip to: 26 +// CHECK-NEXT: /* 8 */ MCD::OPC_CheckField, 2, 2, 0, 7, 0, 0, // Skip to: 22 +// CHECK-NEXT: /* 15 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, 0, // Opcode: InstB, skip to: 22 +// CHECK-NEXT: /* 22 */ MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: InstA +// CHECK-NEXT: /* 26 */ MCD::OPC_Fail, // CHECK: if (!Check(S, DecodeInstB(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; } diff --git a/llvm/test/TableGen/trydecode-emission2.td b/llvm/test/TableGen/trydecode-emission2.td index 7d30474058f73..0584034e41233 100644 --- a/llvm/test/TableGen/trydecode-emission2.td +++ b/llvm/test/TableGen/trydecode-emission2.td @@ -31,14 +31,14 @@ def InstB : TestInstruction { } // CHECK: /* 0 */ MCD::OPC_ExtractField, 2, 1, // Inst{2} ... -// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 31, 0, // Skip to: 38 -// CHECK-NEXT: /* 7 */ MCD::OPC_ExtractField, 5, 3, // Inst{7-5} ... -// CHECK-NEXT: /* 10 */ MCD::OPC_FilterValue, 0, 24, 0, // Skip to: 38 -// CHECK-NEXT: /* 14 */ MCD::OPC_CheckField, 0, 2, 3, 6, 0, // Skip to: 26 -// CHECK-NEXT: /* 20 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, // Opcode: InstB, skip to: 26 -// CHECK-NEXT: /* 26 */ MCD::OPC_CheckField, 3, 2, 0, 6, 0, // Skip to: 38 -// CHECK-NEXT: /* 32 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 1, 0, 0, // Opcode: InstA, skip to: 38 -// CHECK-NEXT: /* 38 */ MCD::OPC_Fail, +// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 36, 0, 0, // Skip to: 44 +// CHECK-NEXT: /* 8 */ MCD::OPC_ExtractField, 5, 3, // Inst{7-5} ... +// CHECK-NEXT: /* 11 */ MCD::OPC_FilterValue, 0, 28, 0, 0, // Skip to: 44 +// CHECK-NEXT: /* 16 */ MCD::OPC_CheckField, 0, 2, 3, 7, 0, 0, // Skip to: 30 +// CHECK-NEXT: /* 23 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, 0, // Opcode: InstB, skip to: 30 +// CHECK-NEXT: /* 30 */ MCD::OPC_CheckField, 3, 2, 0, 7, 0, 0, // Skip to: 44 +// CHECK-NEXT: /* 37 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 1, 0, 0, 0, // Opcode: InstA, skip to: 44 +// CHECK-NEXT: /* 44 */ MCD::OPC_Fail, // CHECK: if (!Check(S, DecodeInstB(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; } // CHECK: if (!Check(S, DecodeInstA(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; } diff --git a/llvm/test/TableGen/trydecode-emission3.td b/llvm/test/TableGen/trydecode-emission3.td index 0abbe62fe337e..4c5be7e1af229 100644 --- a/llvm/test/TableGen/trydecode-emission3.td +++ b/llvm/test/TableGen/trydecode-emission3.td @@ -1,4 +1,4 @@ - // RUN: llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I %p/../../include %s | FileCheck %s +// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s include "llvm/Target/Target.td" diff --git a/llvm/test/TableGen/trydecode-emission4.td b/llvm/test/TableGen/trydecode-emission4.td index 413e4a0d1275a..1e51ba5e40768 100644 --- a/llvm/test/TableGen/trydecode-emission4.td +++ b/llvm/test/TableGen/trydecode-emission4.td @@ -1,4 +1,4 @@ -// RUN: llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I %p/../../include %s | FileCheck %s +// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s // Test for OPC_ExtractField/OPC_CheckField with start bit > 255. // These large start values may arise for architectures with long instruction diff --git a/llvm/utils/TableGen/DecoderEmitter.cpp b/llvm/utils/TableGen/DecoderEmitter.cpp index 0735702abf339..9c6015cc24576 100644 --- a/llvm/utils/TableGen/DecoderEmitter.cpp +++ b/llvm/utils/TableGen/DecoderEmitter.cpp @@ -32,10 +32,8 @@ #include "llvm/Support/CommandLine.h" #include "llvm/Support/Debug.h" #include "llvm/Support/ErrorHandling.h" -#include "llvm/Support/FormatVariadic.h" #include "llvm/Support/FormattedStream.h" #include "llvm/Support/LEB128.h" -#include "llvm/Support/MathExtras.h" #include "llvm/Support/raw_ostream.h" #include "llvm/TableGen/Error.h" #include "llvm/TableGen/Record.h" @@ -78,12 +76,6 @@ static cl::opt<SuppressLevel> DecoderEmitterSuppressDuplicates( "significantly reducing Table Duplications")), cl::init(SUPPRESSION_DISABLE), cl::cat(DisassemblerEmitterCat)); -static cl::opt<uint32_t> - NumToSkipSizeInBytes("num-to-skip-size", - cl::desc("number of bytes to use for num-to-skip " - "entries in the decoder table (2 or 3)"), - cl::init(2), cl::cat(DisassemblerEmitterCat)); - STATISTIC(NumEncodings, "Number of encodings considered"); STATISTIC(NumEncodingsLackingDisasm, "Number of encodings without disassembler info"); @@ -138,29 +130,10 @@ struct DecoderTable : public std::vector<uint8_t> { // in the table for patching. size_t insertNumToSkip() { size_t Size = size(); - insert(end(), NumToSkipSizeInBytes, 0); + insert(end(), 3, 0); return Size; } - - void patchNumToSkip(size_t FixupIdx, uint32_t DestIdx) { - // Calculate the distance from the byte following the fixup entry byte - // to the destination. The Target is calculated from after the - // `NumToSkipSizeInBytes`-byte NumToSkip entry itself, so subtract - // `NumToSkipSizeInBytes` from the displacement here to account for that. - assert(DestIdx > FixupIdx + NumToSkipSizeInBytes && - "Expecting a forward jump in the decoding table"); - uint32_t Delta = DestIdx - FixupIdx - NumToSkipSizeInBytes; - if (!isUIntN(8 * NumToSkipSizeInBytes, Delta)) - PrintFatalError( - "disassembler decoding table too large, try --num-to-skip-size=3"); - - (*this)[FixupIdx] = static_cast<uint8_t>(Delta); - (*this)[FixupIdx + 1] = static_cast<uint8_t>(Delta >> 8); - if (NumToSkipSizeInBytes == 3) - (*this)[FixupIdx + 2] = static_cast<uint8_t>(Delta >> 16); - } }; - struct DecoderTableInfo { DecoderTable Table; FixupScopeList FixupStack; @@ -717,8 +690,19 @@ static void resolveTableFixups(DecoderTable &Table, const FixupList &Fixups, uint32_t DestIdx) { // Any NumToSkip fixups in the current scope can resolve to the // current location. - for (uint32_t FixupIdx : Fixups) - Table.patchNumToSkip(FixupIdx, DestIdx); + for (uint32_t FixupIdx : reverse(Fixups)) { + // Calculate the distance from the byte following the fixup entry byte + // to the destination. The Target is calculated from after the 24-bit + // NumToSkip entry itself, so subtract three from the displacement here + // to account for that. + uint32_t Delta = DestIdx - FixupIdx - 3; + // Our NumToSkip entries are 24-bits. Make sure our table isn't too + // big. + assert(isUInt<24>(Delta)); + Table[FixupIdx] = (uint8_t)Delta; + Table[FixupIdx + 1] = (uint8_t)(Delta >> 8); + Table[FixupIdx + 2] = (uint8_t)(Delta >> 16); + } } // Emit table entries to decode instructions given a segment or segments @@ -775,9 +759,15 @@ void Filter::emitTableEntry(DecoderTableInfo &TableInfo) const { Delegate->emitTableEntries(TableInfo); // Now that we've emitted the body of the handler, update the NumToSkip - // of the filter itself to be able to skip forward when false. - if (PrevFilter) - Table.patchNumToSkip(PrevFilter, Table.size()); + // of the filter itself to be able to skip forward when false. Subtract + // three as to account for the width of the NumToSkip field itself. + if (PrevFilter) { + uint32_t NumToSkip = Table.size() - PrevFilter - 3; + assert(isUInt<24>(NumToSkip) && "disassembler decoding table too large!"); + Table[PrevFilter] = (uint8_t)NumToSkip; + Table[PrevFilter + 1] = (uint8_t)(NumToSkip >> 8); + Table[PrevFilter + 2] = (uint8_t)(NumToSkip >> 16); + } } // If there is no fallthrough, then the final filter should get fixed @@ -824,8 +814,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table, OS << (unsigned)*I++ << ", "; }; - // Emit `NumToSkipSizeInBytes`-byte numtoskip value to OS, returning the - // NumToSkip value. + // Emit 24-bit numtoskip value to OS, returning the NumToSkip value. auto emitNumToSkip = [](DecoderTable::const_iterator &I, formatted_raw_ostream &OS) { uint8_t Byte = *I++; @@ -834,11 +823,9 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table, Byte = *I++; OS << (unsigned)Byte << ", "; NumToSkip |= Byte << 8; - if (NumToSkipSizeInBytes == 3) { - Byte = *I++; - OS << (unsigned)(Byte) << ", "; - NumToSkip |= Byte << 16; - } + Byte = *I++; + OS << (unsigned)(Byte) << ", "; + NumToSkip |= Byte << 16; return NumToSkip; }; @@ -880,7 +867,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table, // The filter value is ULEB128 encoded. emitULEB128(I, OS); - // numtoskip value. + // 24-bit numtoskip value. uint32_t NumToSkip = emitNumToSkip(I, OS); OS << "// Skip to: " << ((I - Table.begin()) + NumToSkip) << "\n"; break; @@ -896,7 +883,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table, // ULEB128 encoded field value. emitULEB128(I, OS); - // numtoskip value. + // 24-bit numtoskip value. uint32_t NumToSkip = emitNumToSkip(I, OS); OS << "// Skip to: " << ((I - Table.begin()) + NumToSkip) << "\n"; break; @@ -906,7 +893,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table, OS << Indent << "MCD::OPC_CheckPredicate, "; emitULEB128(I, OS); - // numtoskip value. + // 24-bit numtoskip value. uint32_t NumToSkip = emitNumToSkip(I, OS); OS << "// Skip to: " << ((I - Table.begin()) + NumToSkip) << "\n"; break; @@ -938,7 +925,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table, // Fallthrough for OPC_TryDecode. - // numtoskip value. + // 24-bit numtoskip value. uint32_t NumToSkip = emitNumToSkip(I, OS); OS << "// Opcode: " << NumberedEncodings[EncodingID] @@ -1424,9 +1411,9 @@ void FilterChooser::emitSingletonTableEntry(DecoderTableInfo &TableInfo, TableInfo.Table.push_back(NumBits); TableInfo.Table.insertULEB128(Ilnd.FieldVal); - // Allocate space in the table for fixup (NumToSkipSizeInBytes) so all - // our relative position calculations work OK even before we fully - // resolve the real value here. + // The fixup is always 24-bits, so go ahead and allocate the space + // in the table so all our relative position calculations work OK even + // before we fully resolve the real value here. // Push location for NumToSkip backpatching. TableInfo.FixupStack.back().push_back(TableInfo.Table.insertNumToSkip()); @@ -2170,18 +2157,7 @@ insertBits(InsnType &field, uint64_t bits, unsigned startBit, unsigned numBits) // decodeInstruction(). static void emitDecodeInstruction(formatted_raw_ostream &OS, bool IsVarLenInst) { - OS << formatv("\nconstexpr unsigned NumToSkipSizeInBytes = {};\n", - NumToSkipSizeInBytes); - OS << R"( -inline unsigned decodeNumToSkip(const uint8_t *&Ptr) { - unsigned NumToSkip = *Ptr++; - NumToSkip |= (*Ptr++) << 8; - if constexpr (NumToSkipSizeInBytes == 3) - NumToSkip |= (*Ptr++) << 16; - return NumToSkip; -} - template <typename InsnType> static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI, InsnType insn, uint64_t Address, @@ -2219,7 +2195,10 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI, // Decode the field value. uint64_t Val = decodeULEB128AndIncUnsafe(++Ptr); bool Failed = Val != CurFieldValue; - unsigned NumToSkip = decodeNumToSkip(Ptr); + // NumToSkip is a plain 24-bit integer. + unsigned NumToSkip = *Ptr++; + NumToSkip |= (*Ptr++) << 8; + NumToSkip |= (*Ptr++) << 16; // Perform the filter operation. if (Failed) @@ -2243,7 +2222,10 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI, uint64_t ExpectedValue = decodeULEB128(++Ptr, &PtrLen); Ptr += PtrLen; bool Failed = ExpectedValue != FieldValue; - unsigned NumToSkip = decodeNumToSkip(Ptr); + // NumToSkip is a plain 24-bit integer. + unsigned NumToSkip = *Ptr++; + NumToSkip |= (*Ptr++) << 8; + NumToSkip |= (*Ptr++) << 16; // If the actual and expected values don't match, skip. if (Failed) @@ -2258,7 +2240,10 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI, case MCD::OPC_CheckPredicate: { // Decode the Predicate Index value. unsigned PIdx = decodeULEB128AndIncUnsafe(++Ptr); - unsigned NumToSkip = decodeNumToSkip(Ptr); + // NumToSkip is a plain 24-bit integer. + unsigned NumToSkip = *Ptr++; + NumToSkip |= (*Ptr++) << 8; + NumToSkip |= (*Ptr++) << 16; // Check the predicate. bool Failed = !checkDecoderPredicate(PIdx, Bits); if (Failed) @@ -2293,7 +2278,10 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI, // Decode the Opcode value. unsigned Opc = decodeULEB128AndIncUnsafe(++Ptr); unsigned DecodeIdx = decodeULEB128AndIncUnsafe(Ptr); - unsigned NumToSkip = decodeNumToSkip(Ptr); + // NumToSkip is a plain 24-bit integer. + unsigned NumToSkip = *Ptr++; + NumToSkip |= (*Ptr++) << 8; + NumToSkip |= (*Ptr++) << 16; // Perform the decode operation. MCInst TmpMI; @@ -2418,9 +2406,6 @@ handleHwModesUnrelatedEncodings(const CodeGenInstruction *Instr, // Emits disassembler code for instruction decoding. void DecoderEmitter::run(raw_ostream &o) { - if (NumToSkipSizeInBytes != 2 && NumToSkipSizeInBytes != 3) - PrintFatalError("Invalid value for num-to-skip-size, must be 2 or 3"); - formatted_raw_ostream OS(o); OS << R"( #include "llvm/MC/MCInst.h" _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
