build: pass C/C++ compiler to FetchContent projects#145
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ingomueller-net merged 1 commit intosubstrait-io:mainfrom Apr 9, 2026
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Mar 30, 2026
This PR removes a work-around I thought would fix a problem with sframes I ran into on my machine leading to linker errors while compiling ANTLR (a dependency of substrait-cpp). Turns out that the root cause is that CMake uses the system default compiler for dependencies fetched with `FetchContent`, which is g++ on my machine (which emits sframes), which may then linked with compilation units compiled by a different compiler, which may break of LTO is enabled. The short-term solution is to set the `CC? and `CXX` environment variables to the same values as `CMAKE_*_COMPILER` when configuring. I have submitted a better mid-term solution as substrait-io/substrait-cpp#145. Signed-off-by: Ingo Müller <ingomueller@google.com>
ingomueller-net
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Mar 31, 2026
This PR removes a work-around I thought would fix a problem with sframes I ran into on my machine leading to linker errors while compiling ANTLR (a dependency of substrait-cpp). Turns out that the root cause is that CMake uses the system default compiler for dependencies fetched with `FetchContent`, which is g++ on my machine (which emits sframes), which may then linked with compilation units compiled by a different compiler, which may break of LTO is enabled. The short-term solution is to set the `CC? and `CXX` environment variables to the same values as `CMAKE_*_COMPILER` when configuring. I have submitted a better mid-term solution as substrait-io/substrait-cpp#145. Signed-off-by: Ingo Müller <ingomueller@google.com>
ingomueller-net
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Mar 31, 2026
This PR removes a work-around I thought would fix a problem with sframes I ran into on my machine leading to linker errors while compiling ANTLR (a dependency of substrait-cpp). Turns out that the root cause is that CMake uses the system default compiler for dependencies fetched with `FetchContent`, which is g++ on my machine (which emits sframes), which may then linked with compilation units compiled by a different compiler, which may break of LTO is enabled. The short-term solution is to set the `CC? and `CXX` environment variables to the same values as `CMAKE_*_COMPILER` when configuring. I have submitted a better mid-term solution as substrait-io/substrait-cpp#145. Signed-off-by: Ingo Müller <ingomueller@google.com>
ingomueller-net
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Mar 31, 2026
This PR removes a work-around I thought would fix a problem with sframes I ran into on my machine leading to linker errors while compiling ANTLR (a dependency of substrait-cpp). Turns out that the root cause is that CMake uses the system default compiler for dependencies fetched with `FetchContent`, which is g++ on my machine (which emits sframes), which may then linked with compilation units compiled by a different compiler, which may break of LTO is enabled. The short-term solution is to set the `CC? and `CXX` environment variables to the same values as `CMAKE_*_COMPILER` when configuring. I have submitted a better mid-term solution as substrait-io/substrait-cpp#145. Signed-off-by: Ingo Müller <ingomueller@google.com>
ingomueller-net
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Apr 1, 2026
This PR removes a work-around I thought would fix a problem with sframes I ran into on my machine leading to linker errors while compiling ANTLR (a dependency of substrait-cpp). Turns out that the root cause is that CMake uses the system default compiler for dependencies fetched with `FetchContent`, which is g++ on my machine (which emits sframes), which may then linked with compilation units compiled by a different compiler, which may break of LTO is enabled. The short-term solution is to set the `CC? and `CXX` environment variables to the same values as `CMAKE_*_COMPILER` when configuring. I have submitted a better mid-term solution as substrait-io/substrait-cpp#145. Signed-off-by: Ingo Müller <ingomueller@google.com>
ingomueller-net
added a commit
to ingomueller-net/substrait-mlir-contrib
that referenced
this pull request
Apr 1, 2026
This PR removes a work-around I thought would fix a problem with sframes I ran into on my machine leading to linker errors while compiling ANTLR (a dependency of substrait-cpp). Turns out that the root cause is that CMake uses the system default compiler for dependencies fetched with `FetchContent`, which is g++ on my machine (which emits sframes), which may then linked with compilation units compiled by a different compiler, which may break of LTO is enabled. The short-term solution is to set the `CC? and `CXX` environment variables to the same values as `CMAKE_*_COMPILER` when configuring. I have submitted a better mid-term solution as substrait-io/substrait-cpp#145. Signed-off-by: Ingo Müller <ingomueller@google.com>
ingomueller-net
added a commit
to substrait-io/substrait-mlir-contrib
that referenced
this pull request
Apr 1, 2026
This PR removes a work-around I thought would fix a problem with sframes I ran into on my machine leading to linker errors while compiling ANTLR (a dependency of substrait-cpp). Turns out that the root cause is that CMake uses the system default compiler for dependencies fetched with `FetchContent`, which is g++ on my machine (which emits sframes), which may then linked with compilation units compiled by a different compiler, which may break of LTO is enabled. The short-term solution is to set the `CC? and `CXX` environment variables to the same values as `CMAKE_*_COMPILER` when configuring. I have submitted a better mid-term solution as substrait-io/substrait-cpp#145. Signed-off-by: Ingo Müller <ingomueller@google.com>
EpsilonPrime
approved these changes
Apr 9, 2026
This PR passes the `CMAKE_(C|CXX)_COMPILER` variables from the current project to the projects fetched with `FetchContent`. By default, the compiler will be chosen from scratch, which may be the content of the `CC` or `CXX` variables or the system default. This is problematic because it may change depending on the evironment where the build is run -- not the configuration. Furthermore, if different compilers and LTO are used, the build may break. Signed-off-by: Ingo Müller <ingomueller@google.com>
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This PR passes the
CMAKE_(C|CXX)_COMPILERvariables from the current project to the projects fetched withFetchContent. By default, the compiler will be chosen from scratch, which may be the content of theCCorCXXvariables or the system default. This is problematic because it may change depending on the evironment where the build is run -- not the configuration. Furthermore, if different compilers and LTO are used, the build may break.