Remove injection of -Werror=implicit-function-declaration
#23465
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sbc100
changed the title
-Werror=implicit-function-declaration. NFC-Werror=implicit-function-declaration
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Indeed, based on #2175 it looks like these errors used to result in run time crashes, but now they will result in linker failure (including the names of the function and the two object files that disagree about its signature). |
I believe this change in the defaults was probably don't back in the day when mismatched function pointers were not otherwise will reported and could lead to hard-to-debug crashes. These days the linker will five a clear error about function signature mistmatches between object files so I think the deviation is no longer worth it. Note: Adding this extra warning actually has some cost because it requires us to understand if the compiler is running C or C++ mode. This is more complicated than is can seem because its possible to specify more than one language mode on the command line. e.g: clang -x c++ myfile.cpp -x c myfile.c We don't currently have great support for this method, and its obviously not common.
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Yeah I think this makes sense. This was from before we even had a linker and were just generating output blindly. |
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do we have a test for the linker behavior? |
dschuff
approved these changes
Jan 22, 2025
We certainly have plenty of signature-mismatch tests in wasm-ld. I don't know if we also test that downstream, but it doesn't seem necessary. |
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I believe this change in the defaults was probably don't back in the day when mismatched function pointers were not otherwise will reported and could lead to hard-to-debug crashes. These days the linker will five a clear error about function signature mistmatches between object files so I think the deviation is no longer worth it.
This change only effect C and not C++.
Note: Adding this extra warning actually has some cost because it requires us to understand if the compiler is running C or C++ mode. This is more complicated than is can seem because its possible to specify more than one language mode on the command line. e.g:
clang -x c++ myfile.cpp -x c myfile.c
We don't currently have great support for this method, and its obviously not common.