[llvm] [LLVM][MC][DecoderEmitter] Add support to specialize decoder per bitwidth (PR #154865)

Mon Sep 1 18:52:50 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-gcc-ubuntu` running on `sie-linux-worker3` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/174/builds/23753

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
50.774 [1792/34/5494] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/CleanupCtadCheck.cpp.o
50.785 [1791/34/5495] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/DurationRewriter.cpp.o
50.798 [1790/34/5496] Building CXX object tools/clang/tools/clang-diff/CMakeFiles/clang-diff.dir/ClangDiff.cpp.o
50.799 [1789/34/5497] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/DurationSubtractionCheck.cpp.o
50.802 [1788/34/5498] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/DurationUnnecessaryConversionCheck.cpp.o
50.815 [1787/34/5499] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/NoInternalDependenciesCheck.cpp.o
50.817 [1786/34/5500] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/NoNamespaceCheck.cpp.o
50.823 [1785/34/5501] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/RedundantStrcatCallsCheck.cpp.o
50.827 [1784/34/5502] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/FasterStrsplitDelimiterCheck.cpp.o
50.835 [1783/34/5503] Building CXX object lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o
FAILED: lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o 
/opt/ccache/bin/g++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GLIBCXX_USE_CXX11_ABI=1 -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/RISCV/Disassembler -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/RISCV/Disassembler -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/RISCV -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/lib/Target/RISCV -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/include -I/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -fvisibility=hidden  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o -MF lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o.d -o lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o -c /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:705:13: error: explicit template specialization cannot have a storage class
  705 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint16_t> = 16;
      |             ^~~~~~
/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:706:13: error: explicit template specialization cannot have a storage class
  706 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint32_t> = 32;
      |             ^~~~~~
/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:708:13: error: explicit template specialization cannot have a storage class
  708 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint64_t> = 48;
      |             ^~~~~~
50.836 [1783/33/5504] Linking CXX executable bin/llvm-ir2vec
50.841 [1783/32/5505] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/StringFindStrContainsCheck.cpp.o
50.842 [1783/31/5506] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/StrCatAppendCheck.cpp.o
50.856 [1783/30/5507] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/TimeSubtractionCheck.cpp.o
50.866 [1783/29/5508] Building CXX object tools/clang/tools/extra/clang-tidy/altera/CMakeFiles/obj.clangTidyAlteraModule.dir/IdDependentBackwardBranchCheck.cpp.o
50.866 [1783/28/5509] Building CXX object tools/clang/tools/extra/clang-move/tool/CMakeFiles/clang-move.dir/ClangMove.cpp.o
50.867 [1783/27/5510] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/TimeComparisonCheck.cpp.o
50.869 [1783/26/5511] Building CXX object tools/clang/tools/extra/clang-tidy/abseil/CMakeFiles/obj.clangTidyAbseilModule.dir/UpgradeDurationConversionsCheck.cpp.o
50.891 [1783/25/5512] Building CXX object tools/clang/lib/Interpreter/CMakeFiles/obj.clangInterpreter.dir/CodeCompletion.cpp.o
50.910 [1783/24/5513] Building CXX object tools/clang/tools/clang-import-test/CMakeFiles/clang-import-test.dir/clang-import-test.cpp.o
50.921 [1783/23/5514] Building CXX object tools/clang/lib/Interpreter/CMakeFiles/obj.clangInterpreter.dir/IncrementalParser.cpp.o
In file included from /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/lib/Interpreter/IncrementalParser.cpp:14:
/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/lib/Interpreter/IncrementalAction.h:37:38: warning: ‘maybe_unused’ attribute ignored [-Wattributes]
   37 |   [[maybe_unused]] CompilerInstance &CI;
      |                                      ^~
50.929 [1783/22/5515] Building CXX object tools/clang/lib/Interpreter/CMakeFiles/obj.clangInterpreter.dir/IncrementalAction.cpp.o
In file included from /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/lib/Interpreter/IncrementalAction.cpp:9:
/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/lib/Interpreter/IncrementalAction.h:37:38: warning: ‘maybe_unused’ attribute ignored [-Wattributes]
   37 |   [[maybe_unused]] CompilerInstance &CI;
      |                                      ^~
50.975 [1783/21/5516] Building CXX object tools/clang/tools/extra/clang-apply-replacements/CMakeFiles/obj.clangApplyReplacements.dir/lib/Tooling/ApplyReplacements.cpp.o
50.988 [1783/20/5517] Building CXX object tools/clang/tools/extra/clang-apply-replacements/tool/CMakeFiles/clang-apply-replacements.dir/ClangApplyReplacementsMain.cpp.o
50.996 [1783/19/5518] Linking CXX static library lib/libclangStaticAnalyzerCheckers.a
50.998 [1783/18/5519] Building CXX object tools/clang/tools/extra/clang-reorder-fields/tool/CMakeFiles/clang-reorder-fields.dir/ClangReorderFields.cpp.o
51.073 [1783/17/5520] Building CXX object tools/clang/lib/Interpreter/CMakeFiles/obj.clangInterpreter.dir/InterpreterUtils.cpp.o
51.117 [1783/16/5521] Building CXX object tools/clang/lib/Interpreter/CMakeFiles/obj.clangInterpreter.dir/Value.cpp.o
51.150 [1783/15/5522] Building CXX object tools/clang/lib/Interpreter/CMakeFiles/obj.clangInterpreter.dir/InterpreterValuePrinter.cpp.o
In file included from /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/clang/lib/Interpreter/InterpreterValuePrinter.cpp:13:

```

</details>

https://github.com/llvm/llvm-project/pull/154865