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

Mon Sep 1 19:04:27 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `sanitizer-x86_64-linux-android` running on `sanitizer-buildbot-android` while building `llvm` at step 2 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/186/builds/12066

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

```
Step 2 (annotate) failure: 'python ../sanitizer_buildbot/sanitizers/zorg/buildbot/builders/sanitizers/buildbot_selector.py' (failure)
...
[5047/5604] Linking CXX static library lib/libclangCodeGen.a
[5048/5604] Linking CXX static library lib/libclangStaticAnalyzerCore.a
[5049/5604] Linking CXX static library lib/libclangTransformer.a
[5050/5604] Linking CXX static library lib/libclangStaticAnalyzerCheckers.a
[5051/5604] Linking CXX static library lib/libclangStaticAnalyzerFrontend.a
[5052/5604] Linking CXX static library lib/libclangFrontendTool.a
[5053/5604] Linking CXX static library lib/libclangInterpreter.a
[5054/5604] Linking CXX executable bin/clang-offload-bundler
[5055/5604] Linking CXX executable bin/lli
[5056/5604] Building CXX object lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o
FAILED: lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes CCACHE_SLOPPINESS=pch_defines,time_macros /usr/bin/ccache /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build0/bin/clang++ -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/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/lib/Target/RISCV/Disassembler -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/lib/Target/RISCV -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/include -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17 -fvisibility=hidden  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -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 /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:705:13: error: explicit specialization cannot have a storage class [-Werror,-Wexplicit-specialization-storage-class]
  705 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint16_t> = 16;
      |             ^~~~~~
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:706:13: error: explicit specialization cannot have a storage class [-Werror,-Wexplicit-specialization-storage-class]
  706 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint32_t> = 32;
      |             ^~~~~~
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:708:13: error: explicit specialization cannot have a storage class [-Werror,-Wexplicit-specialization-storage-class]
  708 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint64_t> = 48;
      |             ^~~~~~
3 errors generated.
[5057/5604] Building InstCombineTables.inc...
[5058/5604] Linking CXX shared module lib/CheckerDependencyHandlingAnalyzerPlugin.so
[5059/5604] Linking CXX executable bin/diagtool
[5060/5604] Linking CXX shared module lib/CheckerOptionHandlingAnalyzerPlugin.so
[5061/5604] Linking CXX shared module lib/SampleAnalyzerPlugin.so
[5062/5604] Linking CXX executable bin/clang-installapi
[5063/5604] Linking CXX executable bin/clang-refactor
[5064/5604] Linking CXX executable bin/clang-diff
[5065/5604] Linking CXX executable bin/clang-import-test
ninja: build stopped: subcommand failed.

How to reproduce locally: https://github.com/google/sanitizers/wiki/SanitizerBotReproduceBuild

@@@STEP_FAILURE@@@

@@@STEP_FAILURE@@@

@@@STEP_FAILURE@@@
Step 8 (bootstrap clang) failure: bootstrap clang (failure)
...
[5047/5604] Linking CXX static library lib/libclangCodeGen.a
[5048/5604] Linking CXX static library lib/libclangStaticAnalyzerCore.a
[5049/5604] Linking CXX static library lib/libclangTransformer.a
[5050/5604] Linking CXX static library lib/libclangStaticAnalyzerCheckers.a
[5051/5604] Linking CXX static library lib/libclangStaticAnalyzerFrontend.a
[5052/5604] Linking CXX static library lib/libclangFrontendTool.a
[5053/5604] Linking CXX static library lib/libclangInterpreter.a
[5054/5604] Linking CXX executable bin/clang-offload-bundler
[5055/5604] Linking CXX executable bin/lli
[5056/5604] Building CXX object lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o
FAILED: lib/Target/RISCV/Disassembler/CMakeFiles/LLVMRISCVDisassembler.dir/RISCVDisassembler.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes CCACHE_SLOPPINESS=pch_defines,time_macros /usr/bin/ccache /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build0/bin/clang++ -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/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/lib/Target/RISCV/Disassembler -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/lib/Target/RISCV -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/include -I/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/include -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -std=c++17 -fvisibility=hidden  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -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 /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:705:13: error: explicit specialization cannot have a storage class [-Werror,-Wexplicit-specialization-storage-class]
  705 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint16_t> = 16;
      |             ^~~~~~
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:706:13: error: explicit specialization cannot have a storage class [-Werror,-Wexplicit-specialization-storage-class]
  706 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint32_t> = 32;
      |             ^~~~~~
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm-project/llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp:708:13: error: explicit specialization cannot have a storage class [-Werror,-Wexplicit-specialization-storage-class]
  708 | template <> static constexpr uint32_t llvm::MCD::InsnBitWidth<uint64_t> = 48;
      |             ^~~~~~
3 errors generated.
[5057/5604] Building InstCombineTables.inc...
[5058/5604] Linking CXX shared module lib/CheckerDependencyHandlingAnalyzerPlugin.so
[5059/5604] Linking CXX executable bin/diagtool
[5060/5604] Linking CXX shared module lib/CheckerOptionHandlingAnalyzerPlugin.so
[5061/5604] Linking CXX shared module lib/SampleAnalyzerPlugin.so
[5062/5604] Linking CXX executable bin/clang-installapi
[5063/5604] Linking CXX executable bin/clang-refactor
[5064/5604] Linking CXX executable bin/clang-diff
[5065/5604] Linking CXX executable bin/clang-import-test
ninja: build stopped: subcommand failed.

How to reproduce locally: https://github.com/google/sanitizers/wiki/SanitizerBotReproduceBuild

program finished with exit code 2
elapsedTime=177.551190

```

</details>

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