Unable to build LLVM with clang on master/stable 1.73

[MasterAwesome]

Build steps

I tried this code:

./configure --enable-llvm-static-stdcpp --enable-optimize-llvm --enable-clang --set llvm.ninja=false --enable-lld
./x.py build src/llvm-project/ src/llvm-project/lld

LLVM configuration options

running: cd "/rust/build/x86_64-unknown-linux-gnu/llvm/build" && CMAKE_PREFIX_PATH="" DESTDIR="" "cmake" "/rust/src/llvm-project/llvm" "-DLLVM_ENABLE_ASSERTIONS=OFF" "-DLLVM_UNREACHABLE_OPTIMIZE=OFF" "-DLLVM_ENABLE_PLUGINS=OFF" "-DLLVM_TARGETS_TO_BUILD=AArch64;ARM;BPF;Hexagon;LoongArch;MSP430;Mips;NVPTX;PowerPC;RISCV;Sparc;SystemZ;WebAssembly;X86" "-DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD=AVR;M68k;CSKY" "-DLLVM_INCLUDE_EXAMPLES=OFF" "-DLLVM_INCLUDE_DOCS=OFF" "-DLLVM_INCLUDE_BENCHMARKS=OFF" "-DLLVM_INCLUDE_TESTS=OFF" "-DLLVM_ENABLE_TERMINFO=OFF" "-DLLVM_ENABLE_LIBEDIT=OFF" "-DLLVM_ENABLE_BINDINGS=OFF" "-DLLVM_ENABLE_Z3_SOLVER=OFF" "-DLLVM_PARALLEL_COMPILE_JOBS=12" "-DLLVM_TARGET_ARCH=x86_64" "-DLLVM_DEFAULT_TARGET_TRIPLE=x86_64-unknown-linux-gnu" "-DLLVM_ENABLE_WARNINGS=OFF" "-DLLVM_INSTALL_UTILS=ON" "-DLLVM_ENABLE_ZSTD=OFF" "-DLLVM_ENABLE_ZLIB=ON" "-DLLVM_ENABLE_LIBXML2=OFF" "-DLLVM_ENABLE_PROJECTS=clang" "-DLLVM_VERSION_SUFFIX=-rust-1.73.0-nightly" "-DCMAKE_INSTALL_MESSAGE=LAZY" "-DCMAKE_C_COMPILER=cc" "-DCMAKE_CXX_COMPILER=c++" "-DCMAKE_ASM_COMPILER=cc" "-DCMAKE_C_FLAGS=-ffunction-sections -fdata-sections -fPIC -m64" "-DCMAKE_CXX_FLAGS=-ffunction-sections -fdata-sections -fPIC -m64" "-DCMAKE_SHARED_LINKER_FLAGS= -Wl,-Bsymbolic -static-libstdc++" "-DCMAKE_MODULE_LINKER_FLAGS= -Wl,-Bsymbolic -static-libstdc++" "-DCMAKE_EXE_LINKER_FLAGS= -Wl,-Bsymbolic -static-libstdc++" "-DCMAKE_INSTALL_PREFIX=/rust/build/x86_64-unknown-linux-gnu/llvm" "-DCMAKE_ASM_FLAGS= -ffunction-sections -fdata-sections -fPIC -m64" "-DCMAKE_BUILD_TYPE=Release"

I expected to see this happen: Build success

Instead, this happened:

[ 34%] Built target llvm-config
[ 34%] Building BPFGenRegisterInfo.inc...
[ 34%] Building LoongArchGenAsmMatcher.inc...
[ 34%] Building BPFGenSubtargetInfo.inc...
[ 34%] Building AArch64GenExegesis.inc...
[ 34%] Building ARMGenDAGISel.inc...
[ 34%] Building ARMGenDisassemblerTables.inc...
[ 34%] Building HexagonGenDAGISel.inc...
[ 34%] Building HexagonGenDFAPacketizer.inc...
[ 34%] Built target BPFCommonTableGen
[ 34%] Building MSP430GenAsmMatcher.inc...
[ 34%] Building LoongArchGenAsmWriter.inc...
In file included from /rust/src/llvm-project/clang/include/clang/Basic/Specifiers.h:20,
                 from /rust/src/llvm-project/clang/include/clang/Basic/Diagnostic.h:20,
                 from /rust/src/llvm-project/clang/include/clang/AST/NestedNameSpecifier.h:18,
                 from /rust/src/llvm-project/clang/include/clang/AST/Type.h:21,
                 from /rust/src/llvm-project/clang/include/clang/AST/CanonicalType.h:17,
                 from /rust/src/llvm-project/clang/include/clang/AST/ASTContext.h:18,
                 from /rust/src/llvm-project/clang/lib/AST/AttrImpl.cpp:13:
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc: In static member function ‘static clang::AArch64SVEPcsAttr* clang::AArch64SVEPcsAttr::CreateImplicit(clang::ASTContext&, clang::SourceRange, Spelling)’:
/rust/src/llvm-project/llvm/include/llvm/Support/ErrorHandling.h:151:3: error: expected primary-expression before ‘do’
  151 |   do {                                                                         \
      |   ^~
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:39:6: note: in expansion of macro ‘llvm_unreachable’
   39 |     (llvm_unreachable("Unknown attribute spelling!"),  AttributeCommonInfo::Form{AttributeCommonInfo::AS_GNU, 0, false /*IsAlignas*/, false /*IsRegularKeywordAttribute*/})));
      |      ^~~~~~~~~~~~~~~~
In file included from /rust/src/llvm-project/clang/lib/AST/AttrImpl.cpp:273:
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:39:6: error: expected ‘)’ before ‘do’
   39 |     (llvm_unreachable("Unknown attribute spelling!"),  AttributeCommonInfo::Form{AttributeCommonInfo::AS_GNU, 0, false /*IsAlignas*/, false /*IsRegularKeywordAttribute*/})));
      |     ~^
      |      )
/rust/src/llvm-project/llvm/include/llvm/Support/ErrorHandling.h:154:5: error: expected ‘)’ before ‘while’
  154 |   } while (false)
      |     ^~~~~
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:39:6: note: in expansion of macro ‘llvm_unreachable’
   39 |     (llvm_unreachable("Unknown attribute spelling!"),  AttributeCommonInfo::Form{AttributeCommonInfo::AS_GNU, 0, false /*IsAlignas*/, false /*IsRegularKeywordAttribute*/})));
      |      ^~~~~~~~~~~~~~~~
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:35:56: note: to match this ‘(’
   35 |   AttributeCommonInfo I(Range, NoSemaHandlerAttribute, (
      |                                                        ^
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:39:172: error: expected ‘,’ or ‘;’ before ‘)’ token
   39 |     (llvm_unreachable("Unknown attribute spelling!"),  AttributeCommonInfo::Form{AttributeCommonInfo::AS_GNU, 0, false /*IsAlignas*/, false /*IsRegularKeywordAttribute*/})));
      |                                                                                                                                                                            ^
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc: In static member function ‘static clang::AArch64SVEPcsAttr* clang::AArch64SVEPcsAttr::Create(clang::ASTContext&, clang::SourceRange, Spelling)’:
/rust/src/llvm-project/llvm/include/llvm/Support/ErrorHandling.h:151:3: error: expected primary-expression before ‘do’
  151 |   do {                                                                         \
      |   ^~
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:48:6: note: in expansion of macro ‘llvm_unreachable’
   48 |     (llvm_unreachable("Unknown attribute spelling!"),  AttributeCommonInfo::Form{AttributeCommonInfo::AS_GNU, 0, false /*IsAlignas*/, false /*IsRegularKeywordAttribute*/})));
      |      ^~~~~~~~~~~~~~~~
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:48:6: error: expected ‘)’ before ‘do’
   48 |     (llvm_unreachable("Unknown attribute spelling!"),  AttributeCommonInfo::Form{AttributeCommonInfo::AS_GNU, 0, false /*IsAlignas*/, false /*IsRegularKeywordAttribute*/})));
      |     ~^
      |      )
/rust/src/llvm-project/llvm/include/llvm/Support/ErrorHandling.h:154:5: error: expected ‘)’ before ‘while’
  154 |   } while (false)
      |     ^~~~~
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:48:6: note: in expansion of macro ‘llvm_unreachable’
   48 |     (llvm_unreachable("Unknown attribute spelling!"),  AttributeCommonInfo::Form{AttributeCommonInfo::AS_GNU, 0, false /*IsAlignas*/, false /*IsRegularKeywordAttribute*/})));
      |      ^~~~~~~~~~~~~~~~
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:44:56: note: to match this ‘(’
   44 |   AttributeCommonInfo I(Range, NoSemaHandlerAttribute, (
      |                                                        ^
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:48:172: error: expected ‘,’ or ‘;’ before ‘)’ token
   48 |     (llvm_unreachable("Unknown attribute spelling!"),  AttributeCommonInfo::Form{AttributeCommonInfo::AS_GNU, 0, false /*IsAlignas*/, false /*IsRegularKeywordAttribute*/})));
      |                                                                                                                                                                            ^
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc: In static member function ‘static clang::AArch64VectorPcsAttr* clang::AArch64VectorPcsAttr::CreateImplicit(clang::ASTContext&, clang::SourceRange, Spelling)’:
/rust/src/llvm-project/llvm/include/llvm/Support/ErrorHandling.h:151:3: error: expected primary-expression before ‘do’
  151 |   do {                                                                         \
      |   ^~
/rust/build/x86_64-unknown-linux-gnu/llvm/build/tools/clang/include/clang/AST/AttrImpl.inc:128:6: note: in expansion of macro ‘llvm_unreachable’
  128 |     (llvm_unreachable("Unknown attribute spelling!"),  AttributeCommonInfo::Form{AttributeCommonInfo::AS_GNU, 0, false /*IsAlignas*/, false /*IsRegularKeywordAttribute*/})));
      |      ^~~~~~~~~~~~~~~~
gmake[2]: *** [tools/clang/lib/AST/CMakeFiles/obj.clangAST.dir/build.make:230: tools/clang/lib/AST/CMakeFiles/obj.clangAST.dir/AttrImpl.cpp.o] Error 1

Version it worked on

Rust stable 1.72.1 release with LLVM 16

Version with regression

Rust stable branch and master branch containing LLVM 17

Build environment details

name	version
ubuntu	23.04
cmake	3.25.1
gcc	12.3.0
g++	12.3.0
make	4.3

@rustbot modify labels: +regression-from-stable-to-stable -regression-untriaged

[MasterAwesome]

This bug is not host compiler specific, fails when building on both clang 17 and gcc 12.3.0 host toolchains (x86_64 is my host). Build succeeds when --enable-clang is not set in ./configure.

[Mark-Simulacrum]

This looks like a low priority problem, likely upstream in LLVM to me. AFAIK, our CI does not test that we can build clang from the LLVM tree we check out.

[MasterAwesome]

This looks like a low priority problem, likely upstream in LLVM to me. AFAIK, our CI does not test that we can build clang from the LLVM tree we check out.

It does look like an upstream bug that occurs when LLVM_UNREACHABLE_OPTIMIZATIONS is set to OFF causing invalid codegen by clang-tblgen. When this is set to ON all works as expected. I will file a upstream issue and see what the solution is. I also found a related commit making ON the default due to incompatibilities with gcc. llvm/llvm-project@38d248a

I also think we should do this as a step in CI when we do upgrade LLVM submodule to ensure there are no regressions for these options offered by bootstrap.

[MasterAwesome]

Filed an upstream bug: llvm/llvm-project#68237