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[LLVM][TableGen] Parameterize NumToSkip in DecoderEmitter (#136456)
- 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 #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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8 files changed

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‎llvm/lib/Target/AArch64/CMakeLists.txt

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,8 @@ tablegen(LLVM AArch64GenAsmWriter.inc -gen-asm-writer)
77
tablegen(LLVM AArch64GenAsmWriter1.inc -gen-asm-writer -asmwriternum=1)
88
tablegen(LLVM AArch64GenCallingConv.inc -gen-callingconv)
99
tablegen(LLVM AArch64GenDAGISel.inc -gen-dag-isel)
10-
tablegen(LLVM AArch64GenDisassemblerTables.inc -gen-disassembler)
10+
tablegen(LLVM AArch64GenDisassemblerTables.inc -gen-disassembler
11+
--large-decoder-table)
1112
tablegen(LLVM AArch64GenFastISel.inc -gen-fast-isel)
1213
tablegen(LLVM AArch64GenGlobalISel.inc -gen-global-isel)
1314
tablegen(LLVM AArch64GenO0PreLegalizeGICombiner.inc -gen-global-isel-combiner

‎llvm/test/TableGen/VarLenDecoder.td

Lines changed: 15 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,5 @@
1-
// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
1+
// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s --check-prefixes=CHECK,CHECK-SMALL
2+
// RUN: llvm-tblgen -gen-disassembler --large-decoder-table -I %p/../../include %s | FileCheck %s --check-prefixes=CHECK,CHECK-LARGE
23

34
include "llvm/Target/Target.td"
45

@@ -46,12 +47,19 @@ def FOO32 : MyVarInst<MemOp32> {
4647
);
4748
}
4849

49-
// CHECK: MCD::OPC_ExtractField, 3, 5, // Inst{7-3} ...
50-
// CHECK-NEXT: MCD::OPC_FilterValue, 8, 4, 0, 0, // Skip to: 12
51-
// CHECK-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 0, // Opcode: FOO16
52-
// CHECK-NEXT: MCD::OPC_FilterValue, 9, 4, 0, 0, // Skip to: 21
53-
// CHECK-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: FOO32
54-
// CHECK-NEXT: MCD::OPC_Fail,
50+
// CHECK-SMALL: MCD::OPC_ExtractField, 3, 5, // Inst{7-3} ...
51+
// CHECK-SMALL-NEXT: MCD::OPC_FilterValue, 8, 4, 0, // Skip to: 11
52+
// CHECK-SMALL-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 0, // Opcode: FOO16
53+
// CHECK-SMALL-NEXT: MCD::OPC_FilterValue, 9, 4, 0, // Skip to: 19
54+
// CHECK-SMALL-NEXT: MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: FOO32
55+
// CHECK-SMALL-NEXT: MCD::OPC_Fail,
56+
57+
// CHECK-LARGE: /* 0 */ MCD::OPC_ExtractField, 3, 5, // Inst{7-3} ...
58+
// CHECK-LARGE-NEXT: /* 3 */ MCD::OPC_FilterValue, 8, 4, 0, 0, // Skip to: 12
59+
// CHECK-LARGE-NEXT: /* 8 */ MCD::OPC_Decode, 178, 2, 0, // Opcode: FOO16
60+
// CHECK-LARGE-NEXT: /* 12 */ MCD::OPC_FilterValue, 9, 4, 0, 0, // Skip to: 21
61+
// CHECK-LARGE-NEXT: /* 17 */ MCD::OPC_Decode, 179, 2, 1, // Opcode: FOO32
62+
// CHECK-LARGE-NEXT: /* 21 */ MCD::OPC_Fail,
5563

5664
// Instruction length table
5765
// CHECK: 27,

‎llvm/test/TableGen/trydecode-emission.td

Lines changed: 24 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,5 @@
11
// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
2+
// RUN: llvm-tblgen -gen-disassembler --large-decoder-table -I %p/../../include %s | FileCheck %s --check-prefix=CHECK-LARGE
23

34
// Check that if decoding of an instruction fails and the instruction does not
45
// have a complete decoder method that can determine if the bitpattern is valid
@@ -34,10 +35,28 @@ def InstB : TestInstruction {
3435
}
3536

3637
// CHECK: /* 0 */ MCD::OPC_ExtractField, 4, 4, // Inst{7-4} ...
37-
// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 18, 0, 0, // Skip to: 26
38-
// CHECK-NEXT: /* 8 */ MCD::OPC_CheckField, 2, 2, 0, 7, 0, 0, // Skip to: 22
39-
// CHECK-NEXT: /* 15 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, 0, // Opcode: InstB, skip to: 22
40-
// CHECK-NEXT: /* 22 */ MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: InstA
41-
// CHECK-NEXT: /* 26 */ MCD::OPC_Fail,
38+
// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 16, 0, // Skip to: 23
39+
// CHECK-NEXT: /* 7 */ MCD::OPC_CheckField, 2, 2, 0, 6, 0, // Skip to: 19
40+
// CHECK-NEXT: /* 13 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, // Opcode: InstB, skip to: 19
41+
// CHECK-NEXT: /* 19 */ MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: InstA
42+
// CHECK-NEXT: /* 23 */ MCD::OPC_Fail,
4243

4344
// CHECK: if (!Check(S, DecodeInstB(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }
45+
46+
// CHECK: unsigned NumToSkip = *Ptr++;
47+
// CHECK-NEXT: NumToSkip |= (*Ptr++) << 8;
48+
// CHECK-NEXT: return NumToSkip;
49+
50+
// CHECK-LARGE: /* 0 */ MCD::OPC_ExtractField, 4, 4, // Inst{7-4} ...
51+
// CHECK-LARGE-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 18, 0, 0, // Skip to: 26
52+
// CHECK-LARGE-NEXT: /* 8 */ MCD::OPC_CheckField, 2, 2, 0, 7, 0, 0, // Skip to: 22
53+
// CHECK-LARGE-NEXT: /* 15 */ MCD::OPC_TryDecode, 179, 2, 0, 0, 0, 0, // Opcode: InstB, skip to: 22
54+
// CHECK-LARGE-NEXT: /* 22 */ MCD::OPC_Decode, 178, 2, 1, // Opcode: InstA
55+
// CHECK-LARGE-NEXT: /* 26 */ MCD::OPC_Fail,
56+
57+
// CHECK-LARGE: if (!Check(S, DecodeInstB(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }
58+
59+
// CHECK-LARGE: unsigned NumToSkip = *Ptr++;
60+
// CHECK-LARGE-NEXT: NumToSkip |= (*Ptr++) << 8;
61+
// CHECK-LARGE-NEXT: NumToSkip |= (*Ptr++) << 16;
62+
// CHECK-LARGE-NEXT: return NumToSkip;

‎llvm/test/TableGen/trydecode-emission2.td

Lines changed: 22 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,5 @@
11
// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
2+
// RUN: llvm-tblgen -gen-disassembler --large-decoder-table -I %p/../../include %s | FileCheck %s --check-prefix=CHECK-LARGE
23

34
include "llvm/Target/Target.td"
45

@@ -31,14 +32,27 @@ def InstB : TestInstruction {
3132
}
3233

3334
// CHECK: /* 0 */ MCD::OPC_ExtractField, 2, 1, // Inst{2} ...
34-
// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 36, 0, 0, // Skip to: 44
35-
// CHECK-NEXT: /* 8 */ MCD::OPC_ExtractField, 5, 3, // Inst{7-5} ...
36-
// CHECK-NEXT: /* 11 */ MCD::OPC_FilterValue, 0, 28, 0, 0, // Skip to: 44
37-
// CHECK-NEXT: /* 16 */ MCD::OPC_CheckField, 0, 2, 3, 7, 0, 0, // Skip to: 30
38-
// CHECK-NEXT: /* 23 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, 0, // Opcode: InstB, skip to: 30
39-
// CHECK-NEXT: /* 30 */ MCD::OPC_CheckField, 3, 2, 0, 7, 0, 0, // Skip to: 44
40-
// CHECK-NEXT: /* 37 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 1, 0, 0, 0, // Opcode: InstA, skip to: 44
41-
// CHECK-NEXT: /* 44 */ MCD::OPC_Fail,
35+
// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 31, 0, // Skip to: 38
36+
// CHECK-NEXT: /* 7 */ MCD::OPC_ExtractField, 5, 3, // Inst{7-5} ...
37+
// CHECK-NEXT: /* 10 */ MCD::OPC_FilterValue, 0, 24, 0, // Skip to: 38
38+
// CHECK-NEXT: /* 14 */ MCD::OPC_CheckField, 0, 2, 3, 6, 0, // Skip to: 26
39+
// CHECK-NEXT: /* 20 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, // Opcode: InstB, skip to: 26
40+
// CHECK-NEXT: /* 26 */ MCD::OPC_CheckField, 3, 2, 0, 6, 0, // Skip to: 38
41+
// CHECK-NEXT: /* 32 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 1, 0, 0, // Opcode: InstA, skip to: 38
42+
// CHECK-NEXT: /* 38 */ MCD::OPC_Fail,
4243

4344
// CHECK: if (!Check(S, DecodeInstB(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }
4445
// CHECK: if (!Check(S, DecodeInstA(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }
46+
47+
// CHECK-LARGE: /* 0 */ MCD::OPC_ExtractField, 2, 1, // Inst{2} ...
48+
// CHECK-LARGE-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 36, 0, 0, // Skip to: 44
49+
// CHECK-LARGE-NEXT: /* 8 */ MCD::OPC_ExtractField, 5, 3, // Inst{7-5} ...
50+
// CHECK-LARGE-NEXT: /* 11 */ MCD::OPC_FilterValue, 0, 28, 0, 0, // Skip to: 44
51+
// CHECK-LARGE-NEXT: /* 16 */ MCD::OPC_CheckField, 0, 2, 3, 7, 0, 0, // Skip to: 30
52+
// CHECK-LARGE-NEXT: /* 23 */ MCD::OPC_TryDecode, 179, 2, 0, 0, 0, 0, // Opcode: InstB, skip to: 30
53+
// CHECK-LARGE-NEXT: /* 30 */ MCD::OPC_CheckField, 3, 2, 0, 7, 0, 0, // Skip to: 44
54+
// CHECK-LARGE-NEXT: /* 37 */ MCD::OPC_TryDecode, 178, 2, 1, 0, 0, 0, // Opcode: InstA, skip to: 44
55+
// CHECK-LARGE-NEXT: /* 44 */ MCD::OPC_Fail,
56+
57+
// CHECK-LARGE: if (!Check(S, DecodeInstB(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }
58+
// CHECK-LARGE: if (!Check(S, DecodeInstA(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }

‎llvm/test/TableGen/trydecode-emission3.td

Lines changed: 16 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,5 @@
1-
// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
1+
// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
2+
// RUN: llvm-tblgen -gen-disassembler --large-decoder-table -I %p/../../include %s | FileCheck %s --check-prefix=CHECK-LARGE
23

34
include "llvm/Target/Target.td"
45

@@ -35,10 +36,19 @@ def InstB : TestInstruction {
3536
}
3637

3738
// CHECK: /* 0 */ MCD::OPC_ExtractField, 4, 4, // Inst{7-4} ...
38-
// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 18, 0, 0, // Skip to: 26
39-
// CHECK-NEXT: /* 8 */ MCD::OPC_CheckField, 2, 2, 0, 7, 0, 0, // Skip to: 22
40-
// CHECK-NEXT: /* 15 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, 0, // Opcode: InstB, skip to: 22
41-
// CHECK-NEXT: /* 22 */ MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: InstA
42-
// CHECK-NEXT: /* 26 */ MCD::OPC_Fail,
39+
// CHECK-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 16, 0, // Skip to: 23
40+
// CHECK-NEXT: /* 7 */ MCD::OPC_CheckField, 2, 2, 0, 6, 0, // Skip to: 19
41+
// CHECK-NEXT: /* 13 */ MCD::OPC_TryDecode, 179, 2, 0, 0, 0, // Opcode: InstB, skip to: 19
42+
// CHECK-NEXT: /* 19 */ MCD::OPC_Decode, 178, 2, 1, // Opcode: InstA
43+
// CHECK-NEXT: /* 23 */ MCD::OPC_Fail,
4344

4445
// CHECK: if (!Check(S, DecodeInstBOp(MI, tmp, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }
46+
47+
// CHECK-LARGE: /* 0 */ MCD::OPC_ExtractField, 4, 4, // Inst{7-4} ...
48+
// CHECK-LARGE-NEXT: /* 3 */ MCD::OPC_FilterValue, 0, 18, 0, 0, // Skip to: 26
49+
// CHECK-LARGE-NEXT: /* 8 */ MCD::OPC_CheckField, 2, 2, 0, 7, 0, 0, // Skip to: 22
50+
// CHECK-LARGE-NEXT: /* 15 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, 0, // Opcode: InstB, skip to: 22
51+
// CHECK-LARGE-NEXT: /* 22 */ MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: InstA
52+
// CHECK-LARGE-NEXT: /* 26 */ MCD::OPC_Fail,
53+
54+
// CHECK-LARGE: if (!Check(S, DecodeInstBOp(MI, tmp, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }

‎llvm/test/TableGen/trydecode-emission4.td

Lines changed: 17 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,5 @@
1-
// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
1+
// RUN: llvm-tblgen -gen-disassembler -I %p/../../include %s | FileCheck %s
2+
// RUN: llvm-tblgen -gen-disassembler --large-decoder-table -I %p/../../include %s | FileCheck %s --check-prefix=CHECK-LARGE
23

34
// Test for OPC_ExtractField/OPC_CheckField with start bit > 255.
45
// These large start values may arise for architectures with long instruction
@@ -32,13 +33,22 @@ def InstB : TestInstruction {
3233
let hasCompleteDecoder = 0;
3334
}
3435

35-
3636
// CHECK: /* 0 */ MCD::OPC_ExtractField, 250, 3, 4, // Inst{509-506} ...
37-
// CHECK-NEXT: /* 4 */ MCD::OPC_FilterValue, 0, 19, 0, 0, // Skip to: 28
38-
// CHECK-NEXT: /* 9 */ MCD::OPC_CheckField, 248, 3, 2, 0, 7, 0, 0, // Skip to: 24
39-
// CHECK-NEXT: /* 17 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, 0, // Opcode: InstB, skip to: 24
40-
// CHECK-NEXT: /* 24 */ MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: InstA
41-
// CHECK-NEXT: /* 28 */ MCD::OPC_Fail,
37+
// CHECK-NEXT: /* 4 */ MCD::OPC_FilterValue, 0, 17, 0, // Skip to: 25
38+
// CHECK-NEXT: /* 8 */ MCD::OPC_CheckField, 248, 3, 2, 0, 6, 0, // Skip to: 21
39+
// CHECK-NEXT: /* 15 */ MCD::OPC_TryDecode, 179, 2, 0, 0, 0, // Opcode: InstB, skip to: 21
40+
// CHECK-NEXT: /* 21 */ MCD::OPC_Decode, 178, 2, 1, // Opcode: InstA
41+
// CHECK-NEXT: /* 25 */ MCD::OPC_Fail,
4242

4343
// CHECK: if (!Check(S, DecodeInstB(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }
4444

45+
46+
// CHECK-LARGE: /* 0 */ MCD::OPC_ExtractField, 250, 3, 4, // Inst{509-506} ...
47+
// CHECK-LARGE-NEXT: /* 4 */ MCD::OPC_FilterValue, 0, 19, 0, 0, // Skip to: 28
48+
// CHECK-LARGE-NEXT: /* 9 */ MCD::OPC_CheckField, 248, 3, 2, 0, 7, 0, 0, // Skip to: 24
49+
// CHECK-LARGE-NEXT: /* 17 */ MCD::OPC_TryDecode, {{[0-9]+}}, {{[0-9]+}}, 0, 0, 0, 0, // Opcode: InstB, skip to: 24
50+
// CHECK-LARGE-NEXT: /* 24 */ MCD::OPC_Decode, {{[0-9]+}}, {{[0-9]+}}, 1, // Opcode: InstA
51+
// CHECK-LARGE-NEXT: /* 28 */ MCD::OPC_Fail,
52+
53+
// CHECK-LARGE: if (!Check(S, DecodeInstB(MI, insn, Address, Decoder))) { DecodeComplete = false; return MCDisassembler::Fail; }
54+

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