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

Wed Apr 16 13:24:06 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-aarch64-quick` running on `linaro-clang-aarch64-quick` while building `llvm` at step 4 "build stage 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/65/builds/15400

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

```
Step 4 (build stage 1) failure: 'ninja' (failure)
...
[1390/4785] Building CXX object tools/clang/lib/Analysis/CMakeFiles/obj.clangAnalysis.dir/FixitUtil.cpp.o
[1391/4785] Building CXX object tools/clang/lib/Analysis/CMakeFiles/obj.clangAnalysis.dir/IntervalPartition.cpp.o
[1392/4785] Building CXX object tools/clang/lib/Analysis/CMakeFiles/obj.clangAnalysis.dir/IssueHash.cpp.o
[1393/4785] Building CXX object tools/clang/lib/Analysis/CMakeFiles/obj.clangAnalysis.dir/LiveVariables.cpp.o
[1394/4785] Building CXX object tools/clang/lib/Analysis/CMakeFiles/obj.clangAnalysis.dir/ObjCNoReturn.cpp.o
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[1398/4785] Building RISCVTargetParserDef.inc...
[1399/4785] Building AArch64GenDisassemblerTables.inc...
FAILED: lib/Target/AArch64/AArch64GenDisassemblerTables.inc /home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/lib/Target/AArch64/AArch64GenDisassemblerTables.inc 
cd /home/tcwg-buildbot/worker/clang-aarch64-quick/stage1 && /home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/bin/llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I /home/tcwg-buildbot/worker/clang-aarch64-quick/llvm/llvm/lib/Target/AArch64 -I/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/include -I/home/tcwg-buildbot/worker/clang-aarch64-quick/llvm/llvm/include -I /home/tcwg-buildbot/worker/clang-aarch64-quick/llvm/llvm/lib/Target /home/tcwg-buildbot/worker/clang-aarch64-quick/llvm/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/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/clang-aarch64-quick/stage1/bin/llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I /home/tcwg-buildbot/worker/clang-aarch64-quick/llvm/llvm/lib/Target/AArch64 -I/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/include -I/home/tcwg-buildbot/worker/clang-aarch64-quick/llvm/llvm/include -I /home/tcwg-buildbot/worker/clang-aarch64-quick/llvm/llvm/lib/Target /home/tcwg-buildbot/worker/clang-aarch64-quick/llvm/llvm/lib/Target/AArch64/AArch64.td --write-if-changed -o lib/Target/AArch64/AArch64GenDisassemblerTables.inc -d lib/Target/AArch64/AArch64GenDisassemblerTables.inc.d
 #0 0x0000c28b3e5ace94 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/bin/llvm-tblgen+0x32ce94)
 #1 0x0000c28b3e5aae94 llvm::sys::RunSignalHandlers() (/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/bin/llvm-tblgen+0x32ae94)
 #2 0x0000c28b3e5ad59c SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #3 0x0000e6d31a36f8f8 (linux-vdso.so.1+0x8f8)
 #4 0x0000e6d319ecf1f0 __pthread_kill_implementation ./nptl/./nptl/pthread_kill.c:44:76
 #5 0x0000e6d319e8a67c gsignal ./signal/../sysdeps/posix/raise.c:27:6
 #6 0x0000e6d319e77130 abort ./stdlib/./stdlib/abort.c:81:7
 #7 0x0000e6d319e83fd4 __assert_fail_base ./assert/./assert/assert.c:91:7
 #8 0x0000e6d319e8404c (/lib/aarch64-linux-gnu/libc.so.6+0x3404c)
 #9 0x0000c28b3e4487fc (anonymous namespace)::FilterChooser::emitTableEntries((anonymous namespace)::DecoderTableInfo&) const DecoderEmitter.cpp:0:0
#10 0x0000c28b3e448668 (anonymous namespace)::FilterChooser::emitTableEntries((anonymous namespace)::DecoderTableInfo&) const DecoderEmitter.cpp:0:0
#11 0x0000c28b3e44491c (anonymous namespace)::DecoderEmitter::run(llvm::raw_ostream&) DecoderEmitter.cpp:0:0
#12 0x0000c28b3e440498 llvm::EmitDecoder(llvm::RecordKeeper const&, llvm::raw_ostream&, llvm::StringRef) (/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/bin/llvm-tblgen+0x1c0498)
#13 0x0000c28b3e45f724 emitDisassembler(llvm::RecordKeeper const&, llvm::raw_ostream&) DisassemblerEmitter.cpp:0:0
#14 0x0000c28b3e5e0954 llvm::TableGen::Emitter::ApplyCallback(llvm::RecordKeeper const&, llvm::raw_ostream&) (/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/bin/llvm-tblgen+0x360954)
#15 0x0000c28b3e5bbd74 llvm::TableGenMain(char const*, std::function<bool (llvm::raw_ostream&, llvm::RecordKeeper const&)>) (/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/bin/llvm-tblgen+0x33bd74)
#16 0x0000c28b3e2d719c tblgen_main(int, char**) (/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/bin/llvm-tblgen+0x5719c)
#17 0x0000e6d319e773fc __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#18 0x0000e6d319e774cc call_init ./csu/../csu/libc-start.c:128:20
#19 0x0000e6d319e774cc __libc_start_main ./csu/../csu/libc-start.c:379:5
#20 0x0000c28b3e2a0d30 _start (/home/tcwg-buildbot/worker/clang-aarch64-quick/stage1/bin/llvm-tblgen+0x20d30)
Aborted
[1400/4785] Building CXX object tools/clang/lib/AST/CMakeFiles/obj.clangAST.dir/Expr.cpp.o
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[1407/4785] Building CXX object tools/clang/lib/Analysis/CMakeFiles/obj.clangAnalysis.dir/ThreadSafety.cpp.o
[1408/4785] Building CXX object tools/clang/lib/Analysis/CMakeFiles/obj.clangAnalysis.dir/ThreadSafetyCommon.cpp.o
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```

</details>

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