llvm20 build error, -DLLVM_ENABLE_PROJECTS="clang;mlir;"

[jackniu1234]

Hi,

I encounter an error when building llvm 20 on MacOS 15, the error messages is below:

/mlir/include/mlir/IR/Location.h:128:10: fatal error: 'mlir/IR/BuiltinLocationAttributes.h.inc' file not found
128 | #include "mlir/IR/BuiltinLocationAttributes.h.inc"

The whole cmake command I used is:

cmake -S llvm -B build -G "Unix Makefiles" -DLLVM_ENABLE_PROJECTS="clang;mlir;" -DCLANG_ENABLE_CIR=ON -DLLVM_BUILD_EXAMPLES=ON -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD="Native“

Besides, this problem misses when building llvm19.

Any help will be greatly appreciated!

[llvmbot]

@llvm/issue-subscribers-mlir

Author: jackniu (jackniu1234)

Hi,

I encounter an error when building llvm 20 on MacOS 15, the error messages is below:

> /mlir/include/mlir/IR/Location.h:128:10: fatal error: 'mlir/IR/BuiltinLocationAttributes.h.inc' file not found
128 | #include "mlir/IR/BuiltinLocationAttributes.h.inc"

The whole cmake command I used is:

> cmake -S llvm -B build -G "Unix Makefiles" -DLLVM_ENABLE_PROJECTS="clang;mlir;" -DCLANG_ENABLE_CIR=ON -DLLVM_BUILD_EXAMPLES=ON -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD="Native“

Besides, this problem misses when building llvm19.

Any help will be greatly appreciated!

[joker-eph]

This indicates in general a missing dependency in CMake, this will be a non-deterministic build failure.

We would need to know which file failed to compile to figure out where is the dependency missing though.

[jackniu1234]

This indicates in general a missing dependency in CMake, this will be a non-deterministic build failure.

We would need to know which file failed to compile to figure out where is the dependency missing though.

Here is a more complete screenshot of the error

[joker-eph]

/Users/niushifu/llvm-project/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM. cpp ; it's in clang and not MLIR it seems.
@bcardosolopes

[jackniu1234]

I finally solved this problem by compiling mlir first then comliping clang and clangIR.

[badumbatish]

@jackniu1234 i think you can potentially add a dependency direction of mlir to clang/clangir in cmake for future users

[Jayesh-P-01]

@jackniu1234 How did this work command wise? Because I have followed the steps of compiling mlir, then clang, then clangIR but I am still getting the same error as you.

[joker-eph]

This kind of error is a missing cmake dependencies, so most of the time resuming the build until it passed can be a solution.

[brianrmurphy]

Sorry for hijacking an existing issue, but I'm also seeing a bunch of quite related problems when I try to build LLVM, and this seems to be the same kind of problem.

I note that you can now run ninja with -t missingdeps to show the exact source of the problem. But fixing it can be challenging for a noob.

Not sure I should hijack an open issue, but the following seems very related:

I'm working on Linux, and was running the following just to try to build reasonably quickly and see what tests are available:

$ cmake -S llvm -B build -G Ninja -DLLVM_ENABLE_PROJECTS="clang;clang-tools-extra;lldb;mlir;polly"       -DLLVM_USE_LINKER=mold       -DLLVM_INSTALL_UTILS=ON       -DCMAKE_BUILD_TYPE=RelWithDebInfo       -DLLVM_TARGETS_TO_BUILD="X86"       -DBUILD_SHARED_LIBS=ON       -DLLVM_LINK_LLVM_DYLIB=OFF       -DCLANG_LINK_CLANG_DYLIB=OFF       -DLLVM_USE_SPLIT_DWARF=ON       -DLLVM_OPTIMIZED_TABLEGEN=ON
$ ninja -C build check-all

which fails. I suspect that the flags and targets I'm using are a bit nonstandard (I saw some of them recommended in a book but had to add others to make cmake happy, and after running check-llvm I found the target check-all which seemed likely to run more tests I could look at), but it seems worthwhile to declare any build dependences so that things can at least try to build.

In any case, adding -t missingdeps shows the actual missing dependencies, and I've managed to fix most of them but am stuck on the following error:

Missing dep: tools/mlir/lib/Rewrite/CMakeFiles/obj.MLIRRewrite.dir/FrozenRewritePatternSet.cpp.o uses /home/brm/code/llvm-project/build/tools/mlir/include/mlir/Dialect/PDL/IR/PDLOps.h.inc (generated by CUSTOM_COMMAND)
Missing dep: tools/mlir/lib/Rewrite/CMakeFiles/obj.MLIRRewrite.dir/FrozenRewritePatternSet.cpp.o uses /home/brm/code/llvm-project/build/tools/mlir/include/mlir/Dialect/PDL/IR/PDLOpsTypes.h.inc (generated by CUSTOM_COMMAND)

In particular, the mlir/include/mlir/mlir/Dialect/.../CMakeLists.txt files seem to have a lot of variation in how they are written, making it tricky for a noob to figure out the right way to declare the dependency here.

Perhaps someone with more experience with the project might want to standardize these? Maybe even try every combination of flags and add missing dependencies?

[brianrmurphy]

Sorry for the digression in my previous comment, I see the more general dependency issue was already discussed back in 2023: https://discourse.llvm.org/t/ninja-can-now-check-for-missing-cmake-dependencies-on-generated-files/74344. Still would be great to have a working build for people newly trying the project code.

I've now managed to fix the dependencies Ninja finds with minor patches to CMakeLists.txt, but now I'm hitting the same missing include file as mentioned abov by @jackniu1234 ('mlir/IR/BuiltinLocationAttributes.h.inc') although included from a different spot, building mlir/tools/mlir-irdl-to-cpp.

I suspect that BuiltinLocationAttributes.td has something missing from the associated CMakeLists.txt that is leaving it out of the dependencies for mlir-headers or something, but the amount of variety across CMakeLists.txt files makes it tough to see the inconsistency.