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

Wed Apr 16 13:16:03 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-arm-ubuntu` running on `linaro-lldb-arm-ubuntu` while building `llvm` at step 4 "build".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/18/builds/14603

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

```
Step 4 (build) failure: build (failure)
...
20.053 [3661/162/2790] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonISelDAGToDAG.cpp.o
20.058 [3660/162/2791] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonISelDAGToDAGHVX.cpp.o
20.063 [3659/162/2792] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonISelLowering.cpp.o
20.066 [3658/162/2793] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonLoopAlign.cpp.o
20.070 [3657/162/2794] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonLoopIdiomRecognition.cpp.o
20.074 [3656/162/2795] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonMachineFunctionInfo.cpp.o
20.077 [3655/162/2796] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonMachineScheduler.cpp.o
20.080 [3654/162/2797] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonMCInstLower.cpp.o
20.086 [3653/162/2798] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonOptAddrMode.cpp.o
20.089 [3652/162/2799] Building AArch64GenDisassemblerTables.inc...
FAILED: lib/Target/AArch64/AArch64GenDisassemblerTables.inc /home/tcwg-buildbot/worker/lldb-arm-ubuntu/build/lib/Target/AArch64/AArch64GenDisassemblerTables.inc 
cd /home/tcwg-buildbot/worker/lldb-arm-ubuntu/build && /home/tcwg-buildbot/worker/lldb-arm-ubuntu/build/bin/llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I /home/tcwg-buildbot/worker/lldb-arm-ubuntu/llvm-project/llvm/lib/Target/AArch64 -I/home/tcwg-buildbot/worker/lldb-arm-ubuntu/build/include -I/home/tcwg-buildbot/worker/lldb-arm-ubuntu/llvm-project/llvm/include -I /home/tcwg-buildbot/worker/lldb-arm-ubuntu/llvm-project/llvm/lib/Target /home/tcwg-buildbot/worker/lldb-arm-ubuntu/llvm-project/llvm/lib/Target/AArch64/AArch64.td --write-if-changed -o lib/Target/AArch64/AArch64GenDisassemblerTables.inc -d lib/Target/AArch64/AArch64GenDisassemblerTables.inc.d
llvm-tblgen: ../llvm-project/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: /home/tcwg-buildbot/worker/lldb-arm-ubuntu/build/bin/llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I /home/tcwg-buildbot/worker/lldb-arm-ubuntu/llvm-project/llvm/lib/Target/AArch64 -I/home/tcwg-buildbot/worker/lldb-arm-ubuntu/build/include -I/home/tcwg-buildbot/worker/lldb-arm-ubuntu/llvm-project/llvm/include -I /home/tcwg-buildbot/worker/lldb-arm-ubuntu/llvm-project/llvm/lib/Target /home/tcwg-buildbot/worker/lldb-arm-ubuntu/llvm-project/llvm/lib/Target/AArch64/AArch64.td --write-if-changed -o lib/Target/AArch64/AArch64GenDisassemblerTables.inc -d lib/Target/AArch64/AArch64GenDisassemblerTables.inc.d
#0 0x00dc72d8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/tcwg-buildbot/worker/lldb-arm-ubuntu/build/bin/llvm-tblgen+0x4272d8)
#1 0x00dc4cd8 llvm::sys::RunSignalHandlers() (/home/tcwg-buildbot/worker/lldb-arm-ubuntu/build/bin/llvm-tblgen+0x424cd8)
#2 0x00dc7b58 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
#3 0xf7b2d6f0 __default_rt_sa_restorer ./signal/../sysdeps/unix/sysv/linux/arm/sigrestorer.S:80:0
#4 0xf7b1db06 ./csu/../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:47:0
#5 0xf7b5d292 __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
#6 0xf7b2c840 gsignal ./signal/../sysdeps/posix/raise.c:27:6
Aborted
20.089 [3652/161/2800] Building AArch64GenFastISel.inc...
20.090 [3652/160/2801] Building PPCGenGlobalISel.inc...
20.090 [3652/159/2802] Building PPCGenInstrInfo.inc...
20.090 [3652/158/2803] Building RISCVGenExegesis.inc...
20.090 [3652/157/2804] Building SparcGenSubtargetInfo.inc...
20.090 [3652/156/2805] Building SPIRVGenInstrInfo.inc...
20.090 [3652/155/2806] Building SPIRVGenMCCodeEmitter.inc...
20.090 [3652/154/2807] Building SPIRVGenTables.inc...
20.090 [3652/153/2808] Building SystemZGenCallingConv.inc...
20.090 [3652/152/2809] Building SystemZGenHLASMAsmWriter.inc...
20.090 [3652/151/2810] Building SystemZGenMCCodeEmitter.inc...
20.090 [3652/150/2811] Building VEGenCallingConv.inc...
20.090 [3652/149/2812] Building VEGenRegisterInfo.inc...
20.090 [3652/148/2813] Building WebAssemblyGenAsmMatcher.inc...
20.090 [3652/147/2814] Building WebAssemblyGenAsmWriter.inc...
20.090 [3652/146/2815] Building WebAssemblyGenDisassemblerTables.inc...
20.091 [3652/145/2816] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonGenExtract.cpp.o
20.092 [3652/144/2817] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonISelLoweringHVX.cpp.o
20.094 [3652/143/2818] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonMask.cpp.o
20.096 [3652/142/2819] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonNewValueJump.cpp.o
20.097 [3652/141/2820] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonOptimizeSZextends.cpp.o
20.099 [3652/140/2821] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonPeephole.cpp.o
20.100 [3652/139/2822] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonRDFOpt.cpp.o
20.101 [3652/138/2823] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonRegisterInfo.cpp.o
20.103 [3652/137/2824] Building CXX object lib/Target/Hexagon/CMakeFiles/LLVMHexagonCodeGen.dir/HexagonSelectionDAGInfo.cpp.o

```

</details>

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