[LLVM][TableGen] Parameterize NumToSkip in DecoderEmitter #136456
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…mitter" (llvm#136017)" (llvm#136068) This reverts commit 6d8bf3c.
jurahul
changed the title
llvmbot
added
backend:AArch64
tablegen
bazel
jurahul
requested review from
topperc and
s-barannikov
and removed request for
keith,
rupprecht and
aaronmondal
|
@llvm/pr-subscribers-tablegen Author: Rahul Joshi (jurahul) Changes
Full diff: https://github.com/llvm/llvm-project/pull/136456.diff 8 Files Affected:
diff --git a/llvm/lib/Target/AArch64/CMakeLists.txt b/llvm/lib/Target/AArch64/CMakeLists.txt
index 2300e479bc110..ba1d1605ec104 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)
+tablegen(LLVM AArch64GenDisassemblerTables.inc -gen-disassembler --num-to-skip-size=3)
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 5cf0bf8911859..b77702ff7c5c1 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, 0, // Skip to: 12
+// CHECK-NEXT: MCD::OPC_FilterValue, 8, 4, 0, // Skip to: 11
// CHECK-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 0, // Opcode: FOO16
-// CHECK-NEXT: MCD::OPC_FilterValue, 9, 4, 0, 0, // Skip to: 21
+// CHECK-NEXT: MCD::OPC_FilterValue, 9, 4, 0, // Skip to: 19
// 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 20d2446eeac7f..2b4239f4fbe65 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, 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-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: 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 0584034e41233..7d30474058f73 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, 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-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: 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 4c5be7e1af229..0abbe62fe337e 100644
--- a/llvm/test/TableGen/trydecode-emission3.td
+++ b/llvm/test/TableGen/trydecode-emission3.td
@@ -1,4 +1,4 @@
-// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
+ // RUN: llvm-tblgen -gen-disassembler --num-to-skip-size=3 -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 1e51ba5e40768..413e4a0d1275a 100644
--- a/llvm/test/TableGen/trydecode-emission4.td
+++ b/llvm/test/TableGen/trydecode-emission4.td
@@ -1,4 +1,4 @@
-// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
+// RUN: llvm-tblgen -gen-disassembler --num-to-skip-size=3 -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 7d63126f65ac4..478ea881aa237 100644
--- a/llvm/utils/TableGen/DecoderEmitter.cpp
+++ b/llvm/utils/TableGen/DecoderEmitter.cpp
@@ -32,8 +32,10 @@
#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"
@@ -76,6 +78,12 @@ 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");
@@ -130,10 +138,29 @@ struct DecoderTable : public std::vector<uint8_t> {
// in the table for patching.
size_t insertNumToSkip() {
size_t Size = size();
- insert(end(), 3, 0);
+ insert(end(), NumToSkipSizeInBytes, 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;
@@ -690,19 +717,8 @@ 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 : 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);
- }
+ for (uint32_t FixupIdx : Fixups)
+ Table.patchNumToSkip(FixupIdx, DestIdx);
}
// Emit table entries to decode instructions given a segment or segments
@@ -759,15 +775,9 @@ 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. 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);
- }
+ // of the filter itself to be able to skip forward when false.
+ if (PrevFilter)
+ Table.patchNumToSkip(PrevFilter, Table.size());
}
// If there is no fallthrough, then the final filter should get fixed
@@ -814,7 +824,8 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
OS << (unsigned)*I++ << ", ";
};
- // Emit 24-bit numtoskip value to OS, returning the NumToSkip value.
+ // Emit `NumToSkipSizeInBytes`-byte numtoskip value to OS, returning the
+ // NumToSkip value.
auto emitNumToSkip = [](DecoderTable::const_iterator &I,
formatted_raw_ostream &OS) {
uint8_t Byte = *I++;
@@ -823,9 +834,11 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
Byte = *I++;
OS << (unsigned)Byte << ", ";
NumToSkip |= Byte << 8;
- Byte = *I++;
- OS << (unsigned)(Byte) << ", ";
- NumToSkip |= Byte << 16;
+ if (NumToSkipSizeInBytes == 3) {
+ Byte = *I++;
+ OS << (unsigned)(Byte) << ", ";
+ NumToSkip |= Byte << 16;
+ }
return NumToSkip;
};
@@ -866,7 +879,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
// The filter value is ULEB128 encoded.
emitULEB128(I, OS);
- // 24-bit numtoskip value.
+ // numtoskip value.
uint32_t NumToSkip = emitNumToSkip(I, OS);
OS << "// Skip to: " << ((I - Table.begin()) + NumToSkip) << "\n";
break;
@@ -881,7 +894,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
// ULEB128 encoded field value.
emitULEB128(I, OS);
- // 24-bit numtoskip value.
+ // numtoskip value.
uint32_t NumToSkip = emitNumToSkip(I, OS);
OS << "// Skip to: " << ((I - Table.begin()) + NumToSkip) << "\n";
break;
@@ -890,7 +903,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
OS << Indent << "MCD::OPC_CheckPredicate, ";
emitULEB128(I, OS);
- // 24-bit numtoskip value.
+ // numtoskip value.
uint32_t NumToSkip = emitNumToSkip(I, OS);
OS << "// Skip to: " << ((I - Table.begin()) + NumToSkip) << "\n";
break;
@@ -920,7 +933,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
// Fallthrough for OPC_TryDecode.
- // 24-bit numtoskip value.
+ // numtoskip value.
uint32_t NumToSkip = emitNumToSkip(I, OS);
OS << "// Opcode: " << NumberedEncodings[EncodingID]
@@ -1392,9 +1405,9 @@ void FilterChooser::emitSingletonTableEntry(DecoderTableInfo &TableInfo,
TableInfo.Table.push_back(NumBits);
TableInfo.Table.insertULEB128(Ilnd.FieldVal);
- // 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.
+ // 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.
// Push location for NumToSkip backpatching.
TableInfo.FixupStack.back().push_back(TableInfo.Table.insertNumToSkip());
@@ -2138,7 +2151,18 @@ 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"(
+static 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,
@@ -2176,10 +2200,7 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI,
// Decode the field value.
uint64_t Val = decodeULEB128AndIncUnsafe(Ptr);
bool Failed = Val != CurFieldValue;
- // NumToSkip is a plain 24-bit integer.
- unsigned NumToSkip = *Ptr++;
- NumToSkip |= (*Ptr++) << 8;
- NumToSkip |= (*Ptr++) << 16;
+ unsigned NumToSkip = decodeNumToSkip(Ptr);
// Perform the filter operation.
if (Failed)
@@ -2203,10 +2224,7 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI,
uint64_t ExpectedValue = decodeULEB128(++Ptr, &PtrLen);
Ptr += PtrLen;
bool Failed = ExpectedValue != FieldValue;
- // NumToSkip is a plain 24-bit integer.
- unsigned NumToSkip = *Ptr++;
- NumToSkip |= (*Ptr++) << 8;
- NumToSkip |= (*Ptr++) << 16;
+ unsigned NumToSkip = decodeNumToSkip(Ptr);
// If the actual and expected values don't match, skip.
if (Failed)
@@ -2221,10 +2239,7 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI,
case MCD::OPC_CheckPredicate: {
// Decode the Predicate Index value.
unsigned PIdx = decodeULEB128AndIncUnsafe(Ptr);
- // NumToSkip is a plain 24-bit integer.
- unsigned NumToSkip = *Ptr++;
- NumToSkip |= (*Ptr++) << 8;
- NumToSkip |= (*Ptr++) << 16;
+ unsigned NumToSkip = decodeNumToSkip(Ptr);
// Check the predicate.
bool Failed = !checkDecoderPredicate(PIdx, Bits);
if (Failed)
@@ -2259,10 +2274,7 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI,
// Decode the Opcode value.
unsigned Opc = decodeULEB128AndIncUnsafe(Ptr);
unsigned DecodeIdx = decodeULEB128AndIncUnsafe(Ptr);
- // NumToSkip is a plain 24-bit integer.
- unsigned NumToSkip = *Ptr++;
- NumToSkip |= (*Ptr++) << 8;
- NumToSkip |= (*Ptr++) << 16;
+ unsigned NumToSkip = decodeNumToSkip(Ptr);
// Perform the decode operation.
MCInst TmpMI;
@@ -2387,6 +2399,9 @@ 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"
diff --git a/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel b/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
index b77ddf634eec6..1bfb07eec6f3a 100644
--- a/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
@@ -2148,7 +2148,7 @@ llvm_target_lib_list = [lib for lib in [
"lib/Target/AArch64/AArch64GenSubtargetInfo.inc",
),
(
- ["-gen-disassembler"],
+ ["-gen-disassembler", "--num-to-skip-size=3"],
"lib/Target/AArch64/AArch64GenDisassemblerTables.inc",
),
(
|
|
@llvm/pr-subscribers-backend-aarch64 Author: Rahul Joshi (jurahul) Changes
Full diff: https://github.com/llvm/llvm-project/pull/136456.diff 8 Files Affected:
diff --git a/llvm/lib/Target/AArch64/CMakeLists.txt b/llvm/lib/Target/AArch64/CMakeLists.txt
index 2300e479bc110..ba1d1605ec104 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)
+tablegen(LLVM AArch64GenDisassemblerTables.inc -gen-disassembler --num-to-skip-size=3)
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 5cf0bf8911859..b77702ff7c5c1 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, 0, // Skip to: 12
+// CHECK-NEXT: MCD::OPC_FilterValue, 8, 4, 0, // Skip to: 11
// CHECK-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 0, // Opcode: FOO16
-// CHECK-NEXT: MCD::OPC_FilterValue, 9, 4, 0, 0, // Skip to: 21
+// CHECK-NEXT: MCD::OPC_FilterValue, 9, 4, 0, // Skip to: 19
// 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 20d2446eeac7f..2b4239f4fbe65 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, 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-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: 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 0584034e41233..7d30474058f73 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, 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-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: 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 4c5be7e1af229..0abbe62fe337e 100644
--- a/llvm/test/TableGen/trydecode-emission3.td
+++ b/llvm/test/TableGen/trydecode-emission3.td
@@ -1,4 +1,4 @@
-// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
+ // RUN: llvm-tblgen -gen-disassembler --num-to-skip-size=3 -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 1e51ba5e40768..413e4a0d1275a 100644
--- a/llvm/test/TableGen/trydecode-emission4.td
+++ b/llvm/test/TableGen/trydecode-emission4.td
@@ -1,4 +1,4 @@
-// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
+// RUN: llvm-tblgen -gen-disassembler --num-to-skip-size=3 -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 7d63126f65ac4..478ea881aa237 100644
--- a/llvm/utils/TableGen/DecoderEmitter.cpp
+++ b/llvm/utils/TableGen/DecoderEmitter.cpp
@@ -32,8 +32,10 @@
#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"
@@ -76,6 +78,12 @@ 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");
@@ -130,10 +138,29 @@ struct DecoderTable : public std::vector<uint8_t> {
// in the table for patching.
size_t insertNumToSkip() {
size_t Size = size();
- insert(end(), 3, 0);
+ insert(end(), NumToSkipSizeInBytes, 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;
@@ -690,19 +717,8 @@ 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 : 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);
- }
+ for (uint32_t FixupIdx : Fixups)
+ Table.patchNumToSkip(FixupIdx, DestIdx);
}
// Emit table entries to decode instructions given a segment or segments
@@ -759,15 +775,9 @@ 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. 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);
- }
+ // of the filter itself to be able to skip forward when false.
+ if (PrevFilter)
+ Table.patchNumToSkip(PrevFilter, Table.size());
}
// If there is no fallthrough, then the final filter should get fixed
@@ -814,7 +824,8 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
OS << (unsigned)*I++ << ", ";
};
- // Emit 24-bit numtoskip value to OS, returning the NumToSkip value.
+ // Emit `NumToSkipSizeInBytes`-byte numtoskip value to OS, returning the
+ // NumToSkip value.
auto emitNumToSkip = [](DecoderTable::const_iterator &I,
formatted_raw_ostream &OS) {
uint8_t Byte = *I++;
@@ -823,9 +834,11 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
Byte = *I++;
OS << (unsigned)Byte << ", ";
NumToSkip |= Byte << 8;
- Byte = *I++;
- OS << (unsigned)(Byte) << ", ";
- NumToSkip |= Byte << 16;
+ if (NumToSkipSizeInBytes == 3) {
+ Byte = *I++;
+ OS << (unsigned)(Byte) << ", ";
+ NumToSkip |= Byte << 16;
+ }
return NumToSkip;
};
@@ -866,7 +879,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
// The filter value is ULEB128 encoded.
emitULEB128(I, OS);
- // 24-bit numtoskip value.
+ // numtoskip value.
uint32_t NumToSkip = emitNumToSkip(I, OS);
OS << "// Skip to: " << ((I - Table.begin()) + NumToSkip) << "\n";
break;
@@ -881,7 +894,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
// ULEB128 encoded field value.
emitULEB128(I, OS);
- // 24-bit numtoskip value.
+ // numtoskip value.
uint32_t NumToSkip = emitNumToSkip(I, OS);
OS << "// Skip to: " << ((I - Table.begin()) + NumToSkip) << "\n";
break;
@@ -890,7 +903,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
OS << Indent << "MCD::OPC_CheckPredicate, ";
emitULEB128(I, OS);
- // 24-bit numtoskip value.
+ // numtoskip value.
uint32_t NumToSkip = emitNumToSkip(I, OS);
OS << "// Skip to: " << ((I - Table.begin()) + NumToSkip) << "\n";
break;
@@ -920,7 +933,7 @@ void DecoderEmitter::emitTable(formatted_raw_ostream &OS, DecoderTable &Table,
// Fallthrough for OPC_TryDecode.
- // 24-bit numtoskip value.
+ // numtoskip value.
uint32_t NumToSkip = emitNumToSkip(I, OS);
OS << "// Opcode: " << NumberedEncodings[EncodingID]
@@ -1392,9 +1405,9 @@ void FilterChooser::emitSingletonTableEntry(DecoderTableInfo &TableInfo,
TableInfo.Table.push_back(NumBits);
TableInfo.Table.insertULEB128(Ilnd.FieldVal);
- // 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.
+ // 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.
// Push location for NumToSkip backpatching.
TableInfo.FixupStack.back().push_back(TableInfo.Table.insertNumToSkip());
@@ -2138,7 +2151,18 @@ 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"(
+static 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,
@@ -2176,10 +2200,7 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI,
// Decode the field value.
uint64_t Val = decodeULEB128AndIncUnsafe(Ptr);
bool Failed = Val != CurFieldValue;
- // NumToSkip is a plain 24-bit integer.
- unsigned NumToSkip = *Ptr++;
- NumToSkip |= (*Ptr++) << 8;
- NumToSkip |= (*Ptr++) << 16;
+ unsigned NumToSkip = decodeNumToSkip(Ptr);
// Perform the filter operation.
if (Failed)
@@ -2203,10 +2224,7 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI,
uint64_t ExpectedValue = decodeULEB128(++Ptr, &PtrLen);
Ptr += PtrLen;
bool Failed = ExpectedValue != FieldValue;
- // NumToSkip is a plain 24-bit integer.
- unsigned NumToSkip = *Ptr++;
- NumToSkip |= (*Ptr++) << 8;
- NumToSkip |= (*Ptr++) << 16;
+ unsigned NumToSkip = decodeNumToSkip(Ptr);
// If the actual and expected values don't match, skip.
if (Failed)
@@ -2221,10 +2239,7 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI,
case MCD::OPC_CheckPredicate: {
// Decode the Predicate Index value.
unsigned PIdx = decodeULEB128AndIncUnsafe(Ptr);
- // NumToSkip is a plain 24-bit integer.
- unsigned NumToSkip = *Ptr++;
- NumToSkip |= (*Ptr++) << 8;
- NumToSkip |= (*Ptr++) << 16;
+ unsigned NumToSkip = decodeNumToSkip(Ptr);
// Check the predicate.
bool Failed = !checkDecoderPredicate(PIdx, Bits);
if (Failed)
@@ -2259,10 +2274,7 @@ static DecodeStatus decodeInstruction(const uint8_t DecodeTable[], MCInst &MI,
// Decode the Opcode value.
unsigned Opc = decodeULEB128AndIncUnsafe(Ptr);
unsigned DecodeIdx = decodeULEB128AndIncUnsafe(Ptr);
- // NumToSkip is a plain 24-bit integer.
- unsigned NumToSkip = *Ptr++;
- NumToSkip |= (*Ptr++) << 8;
- NumToSkip |= (*Ptr++) << 16;
+ unsigned NumToSkip = decodeNumToSkip(Ptr);
// Perform the decode operation.
MCInst TmpMI;
@@ -2387,6 +2399,9 @@ 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"
diff --git a/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel b/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
index b77ddf634eec6..1bfb07eec6f3a 100644
--- a/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/llvm/BUILD.bazel
@@ -2148,7 +2148,7 @@ llvm_target_lib_list = [lib for lib in [
"lib/Target/AArch64/AArch64GenSubtargetInfo.inc",
),
(
- ["-gen-disassembler"],
+ ["-gen-disassembler", "--num-to-skip-size=3"],
"lib/Target/AArch64/AArch64GenDisassemblerTables.inc",
),
(
|
jurahul
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/18/builds/14805 Here is the relevant piece of the build log for the reference |
|
Note: this is failing for our downstream toolchain due to a hard-coded field, specfically due to '178' being used, whereas our downstream target ends up with '179'. Is it necessary to hard code the values? I observe other checks in these tests use regular expressions to avoid having to deal with hard-coded fields and opcodes. |
I agree this is fragile. This value is going to change anytime a new |
I didn't realize that the test used a RE instead of hard-coded values in the earlier form. Will fix the new test to use the same. |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/146/builds/2759 Here is the relevant piece of the build log for the reference |
|
Thank you! I gave one example, but all of your modified tests had this issue. |
|
I see. Will push a new fix for all other tests sometime today
…On Tue, Apr 22, 2025 at 8:41 AM Alan Phipps ***@***.***> wrote:
Thank you! I gave one example, but all of your modified tests had this
issue.
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<#136456 (comment)>
Thank you! I gave one example, but all of your modified tests had this
issue.
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to IanWood1/llvm-project
that referenced
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May 6, 2025
- Add command line option `num-to-skip-size` to parameterize the size of `NumToSkip` bytes in the decoder table. Default value will be 2, and targets that need larger size can use 3. - Keep all existing targets, except AArch64, to use size 2, and change AArch64 to use size 3 since it run into the "disassembler decoding table too large" error with size 2. - Additional fixes on top of earlier revert: mark `decodeNumToSkip` as static (not necessary anymore as the generated code is now in anonymous namespace, but doing it for consistency) and incorporate Bazel build changes from llvm#136212 - Following is a rough reduction in size for the decoder tables by switching to size 2. ``` Target Old Size New Size % Reduction ================================================ AArch64 153254 153254 0.00 AMDGPU 471566 412805 12.46 ARC 5724 5061 11.58 ARM 84936 73831 13.07 AVR 1497 1306 12.76 BPF 2172 1927 11.28 CSKY 10064 8692 13.63 Hexagon 47967 41965 12.51 Lanai 1108 982 11.37 LoongArch 24446 21621 11.56 MSP430 4200 3716 11.52 Mips 36330 31415 13.53 PPC 31897 28098 11.91 RISCV 37979 32790 13.66 Sparc 8331 7252 12.95 SystemZ 36722 32248 12.18 VE 48296 42873 11.23 XCore 2590 2316 10.58 Xtensa 3827 3316 13.35 ```
IanWood1
pushed a commit
to IanWood1/llvm-project
that referenced
this pull request
May 6, 2025
- Add command line option `num-to-skip-size` to parameterize the size of `NumToSkip` bytes in the decoder table. Default value will be 2, and targets that need larger size can use 3. - Keep all existing targets, except AArch64, to use size 2, and change AArch64 to use size 3 since it run into the "disassembler decoding table too large" error with size 2. - Additional fixes on top of earlier revert: mark `decodeNumToSkip` as static (not necessary anymore as the generated code is now in anonymous namespace, but doing it for consistency) and incorporate Bazel build changes from llvm#136212 - Following is a rough reduction in size for the decoder tables by switching to size 2. ``` Target Old Size New Size % Reduction ================================================ AArch64 153254 153254 0.00 AMDGPU 471566 412805 12.46 ARC 5724 5061 11.58 ARM 84936 73831 13.07 AVR 1497 1306 12.76 BPF 2172 1927 11.28 CSKY 10064 8692 13.63 Hexagon 47967 41965 12.51 Lanai 1108 982 11.37 LoongArch 24446 21621 11.56 MSP430 4200 3716 11.52 Mips 36330 31415 13.53 PPC 31897 28098 11.91 RISCV 37979 32790 13.66 Sparc 8331 7252 12.95 SystemZ 36722 32248 12.18 VE 48296 42873 11.23 XCore 2590 2316 10.58 Xtensa 3827 3316 13.35 ```
IanWood1
pushed a commit
to IanWood1/llvm-project
that referenced
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May 6, 2025
- Add command line option `num-to-skip-size` to parameterize the size of `NumToSkip` bytes in the decoder table. Default value will be 2, and targets that need larger size can use 3. - Keep all existing targets, except AArch64, to use size 2, and change AArch64 to use size 3 since it run into the "disassembler decoding table too large" error with size 2. - Additional fixes on top of earlier revert: mark `decodeNumToSkip` as static (not necessary anymore as the generated code is now in anonymous namespace, but doing it for consistency) and incorporate Bazel build changes from llvm#136212 - Following is a rough reduction in size for the decoder tables by switching to size 2. ``` Target Old Size New Size % Reduction ================================================ AArch64 153254 153254 0.00 AMDGPU 471566 412805 12.46 ARC 5724 5061 11.58 ARM 84936 73831 13.07 AVR 1497 1306 12.76 BPF 2172 1927 11.28 CSKY 10064 8692 13.63 Hexagon 47967 41965 12.51 Lanai 1108 982 11.37 LoongArch 24446 21621 11.56 MSP430 4200 3716 11.52 Mips 36330 31415 13.53 PPC 31897 28098 11.91 RISCV 37979 32790 13.66 Sparc 8331 7252 12.95 SystemZ 36722 32248 12.18 VE 48296 42873 11.23 XCore 2590 2316 10.58 Xtensa 3827 3316 13.35 ```
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num-to-skip-sizeto parameterize the size ofNumToSkipbytes in the decoder table. Default value will be 2, and targets that need larger size can use 3.decodeNumToSkipas static (not necessary anymore as the generated code is now in anonymous namespace, but doing it for consistency) and incorporate Bazel build changes from Port a new flag for AArch64 tablegen to Bazel rules #136212