[llvm] [LLVM][TableGen] Parameterize NumToSkip in DecoderEmitter (PR #135882)

Wed Apr 16 14:59:38 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `openmp-gcc-x86_64-linux-debian` running on `gribozavr4` while building `llvm` at step 5 "compile-openmp".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/70/builds/8538

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (compile-openmp) failure: build (failure)
...
8.636 [2763/96/2684] Building AArch64GenO0PreLegalizeGICombiner.inc...
8.649 [2762/96/2685] Building AArch64GenPostLegalizeGICombiner.inc...
8.657 [2761/96/2686] Building AArch64GenPostLegalizeGILowering.inc...
8.669 [2760/96/2687] Building LanaiGenDAGISel.inc...
8.677 [2759/96/2688] Building LanaiGenSubtargetInfo.inc...
8.693 [2758/96/2689] Building AArch64GenPreLegalizeGICombiner.inc...
8.748 [2757/96/2690] Building LoongArchGenMCPseudoLowering.inc...
8.757 [2756/96/2691] Building AArch64GenMCCodeEmitter.inc...
8.773 [2755/96/2692] Building LoongArchGenMCCodeEmitter.inc...
8.784 [2754/96/2693] Building AArch64GenDisassemblerTables.inc...
FAILED: lib/Target/AArch64/AArch64GenDisassemblerTables.inc /b/1/openmp-gcc-x86_64-linux-debian/llvm.build/lib/Target/AArch64/AArch64GenDisassemblerTables.inc 
cd /b/1/openmp-gcc-x86_64-linux-debian/llvm.build && /b/1/openmp-gcc-x86_64-linux-debian/llvm.build/bin/llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I /b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/lib/Target/AArch64 -I/b/1/openmp-gcc-x86_64-linux-debian/llvm.build/include -I/b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/include -I /b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/lib/Target /b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/lib/Target/AArch64/AArch64.td --write-if-changed -o lib/Target/AArch64/AArch64GenDisassemblerTables.inc -d lib/Target/AArch64/AArch64GenDisassemblerTables.inc.d
llvm-tblgen: /b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/utils/TableGen/DecoderEmitter.cpp:151: void (anonymous namespace)::DecoderTable::patchNumToSkip(size_t, uint32_t): Assertion `DestIdx > FixupIdx + NumToSkipSizeInBytes && "Expecting a forward jump in the decoding table"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /b/1/openmp-gcc-x86_64-linux-debian/llvm.build/bin/llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I /b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/lib/Target/AArch64 -I/b/1/openmp-gcc-x86_64-linux-debian/llvm.build/include -I/b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/include -I /b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/lib/Target /b/1/openmp-gcc-x86_64-linux-debian/llvm.src/llvm/lib/Target/AArch64/AArch64.td --write-if-changed -o lib/Target/AArch64/AArch64GenDisassemblerTables.inc -d lib/Target/AArch64/AArch64GenDisassemblerTables.inc.d
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  llvm-tblgen     0x0000000000727757
1  llvm-tblgen     0x000000000072535e
2  llvm-tblgen     0x0000000000727dfa
3  libpthread.so.0 0x00007fda59db6140
4  libc.so.6       0x00007fda598cad51 gsignal + 321
5  libc.so.6       0x00007fda598b4537 abort + 291
6  libc.so.6       0x00007fda598b440f
7  libc.so.6       0x00007fda598c36d2
8  llvm-tblgen     0x00000000005c6315
9  llvm-tblgen     0x00000000005bd01d
10 llvm-tblgen     0x00000000005bd1f7
11 llvm-tblgen     0x00000000005b945b
12 llvm-tblgen     0x00000000005b4b07
13 llvm-tblgen     0x00000000005d68fb
14 llvm-tblgen     0x00000000007591e8
15 llvm-tblgen     0x000000000073035a
16 llvm-tblgen     0x000000000043fb79
17 libc.so.6       0x00007fda598b5d7a __libc_start_main + 234
18 llvm-tblgen     0x000000000040874a
Aborted
8.787 [2754/95/2694] Building LoongArchGenAsmWriter.inc...
8.795 [2754/94/2695] Building LanaiGenInstrInfo.inc...
8.798 [2754/93/2696] Building LoongArchGenDisassemblerTables.inc...
8.819 [2754/92/2697] Building LoongArchGenAsmMatcher.inc...
8.823 [2754/91/2698] Building AArch64GenSystemOperands.inc...
8.890 [2754/90/2699] Building MipsGenCallingConv.inc...
8.910 [2754/89/2700] Building ARMGenFastISel.inc...
8.945 [2754/88/2701] Building HexagonGenMCCodeEmitter.inc...
8.971 [2754/87/2702] Building MSP430GenCallingConv.inc...
8.984 [2754/86/2703] Building HexagonGenDisassemblerTables.inc...
9.005 [2754/85/2704] Building AArch64GenRegisterBank.inc...
9.016 [2754/84/2705] Building MipsGenAsmMatcher.inc...

```

</details>

https://github.com/llvm/llvm-project/pull/135882