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

Wed Apr 16 13:31:12 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-aarch64-sharedlibs` running on `linaro-flang-aarch64-sharedlibs` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/80/builds/12663

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
22.788 [5794/162/1633] Copying clang's avx512vlfp16intrin.h...
22.790 [5793/162/1634] Copying clang's avx512vlintrin.h...
22.791 [5792/162/1635] Copying clang's avx512vlvbmi2intrin.h...
22.793 [5791/162/1636] Copying clang's avx512vlvnniintrin.h...
22.795 [5790/162/1637] Copying clang's avx512vlvp2intersectintrin.h...
22.796 [5789/162/1638] Copying clang's avx512vnniintrin.h...
22.798 [5788/162/1639] Copying clang's avx512vp2intersectintrin.h...
22.800 [5787/162/1640] Copying clang's avx512vpopcntdqintrin.h...
22.801 [5786/162/1641] Copying clang's avx512vpopcntdqvlintrin.h...
22.804 [5785/162/1642] Building AArch64GenDisassemblerTables.inc...
FAILED: lib/Target/AArch64/AArch64GenDisassemblerTables.inc /home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/lib/Target/AArch64/AArch64GenDisassemblerTables.inc 
cd /home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build && /home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/bin/llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I /home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/llvm-project/llvm/lib/Target/AArch64 -I/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/include -I/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/llvm-project/llvm/include -I /home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/llvm-project/llvm/lib/Target /home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/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/flang-aarch64-sharedlibs/build/bin/llvm-tblgen -gen-disassembler --num-to-skip-size=3 -I /home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/llvm-project/llvm/lib/Target/AArch64 -I/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/include -I/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/llvm-project/llvm/include -I /home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/llvm-project/llvm/lib/Target /home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/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 0x0000f0f4d9d98ed0 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/bin/../lib/libLLVMSupport.so.21.0git+0x198ed0)
 #1 0x0000f0f4d9d96d10 llvm::sys::RunSignalHandlers() (/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/bin/../lib/libLLVMSupport.so.21.0git+0x196d10)
 #2 0x0000f0f4d9d995ec SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #3 0x0000f0f4da1288f8 (linux-vdso.so.1+0x8f8)
 #4 0x0000f0f4d9acf1f0 __pthread_kill_implementation ./nptl/./nptl/pthread_kill.c:44:76
 #5 0x0000f0f4d9a8a67c gsignal ./signal/../sysdeps/posix/raise.c:27:6
 #6 0x0000f0f4d9a77130 abort ./stdlib/./stdlib/abort.c:81:7
 #7 0x0000f0f4d9a83fd4 __assert_fail_base ./assert/./assert/assert.c:91:7
 #8 0x0000f0f4d9a8404c (/lib/aarch64-linux-gnu/libc.so.6+0x3404c)
 #9 0x0000afd26eeb1c7c (anonymous namespace)::FilterChooser::emitTableEntries((anonymous namespace)::DecoderTableInfo&) const DecoderEmitter.cpp:0:0
#10 0x0000afd26eeb1ae8 (anonymous namespace)::FilterChooser::emitTableEntries((anonymous namespace)::DecoderTableInfo&) const DecoderEmitter.cpp:0:0
#11 0x0000afd26eeadd9c (anonymous namespace)::DecoderEmitter::run(llvm::raw_ostream&) DecoderEmitter.cpp:0:0
#12 0x0000afd26eea9918 llvm::EmitDecoder(llvm::RecordKeeper const&, llvm::raw_ostream&, llvm::StringRef) (/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/bin/llvm-tblgen+0x1b9918)
#13 0x0000afd26eec8ba4 emitDisassembler(llvm::RecordKeeper const&, llvm::raw_ostream&) DisassemblerEmitter.cpp:0:0
#14 0x0000f0f4da079e94 llvm::TableGen::Emitter::ApplyCallback(llvm::RecordKeeper const&, llvm::raw_ostream&) (/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/bin/../lib/libLLVMTableGen.so.21.0git+0x49e94)
#15 0x0000f0f4da04dcd0 llvm::TableGenMain(char const*, std::function<bool (llvm::raw_ostream&, llvm::RecordKeeper const&)>) (/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/bin/../lib/libLLVMTableGen.so.21.0git+0x1dcd0)
#16 0x0000afd26ed4061c tblgen_main(int, char**) (/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/bin/llvm-tblgen+0x5061c)
#17 0x0000f0f4d9a773fc __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#18 0x0000f0f4d9a774cc call_init ./csu/../csu/libc-start.c:128:20
#19 0x0000f0f4d9a774cc __libc_start_main ./csu/../csu/libc-start.c:379:5
#20 0x0000afd26ed0a1b0 _start (/home/tcwg-buildbot/worker/flang-aarch64-sharedlibs/build/bin/llvm-tblgen+0x1a1b0)
Aborted
22.804 [5785/161/1643] Copying clang's avxifmaintrin.h...
22.804 [5785/160/1644] Copying clang's avxintrin.h...
22.804 [5785/159/1645] Copying clang's avxneconvertintrin.h...
22.804 [5785/158/1646] Copying clang's avxvnniint16intrin.h...
22.805 [5785/157/1647] Copying clang's avxvnniint8intrin.h...
22.805 [5785/156/1648] Copying clang's avxvnniintrin.h...
22.805 [5785/155/1649] Copying clang's bmi2intrin.h...
22.805 [5785/154/1650] Copying clang's bmiintrin.h...
22.805 [5785/153/1651] Copying clang's cetintrin.h...
22.805 [5785/152/1652] Copying clang's cldemoteintrin.h...
22.805 [5785/151/1653] Copying clang's clflushoptintrin.h...

```

</details>

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