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i686 mingw-w64 comdat functions use wrong .text section name #38566

@rnk

Description

@rnk
Bugzilla Link 39218
Resolution FIXED
Resolved on Nov 29, 2018 16:09
Version trunk
OS Windows NT
Blocks #38454
CC @tstellar
Fixed by commit(s) r347431 r347931

Extended Description

If you simply build and run the example from the original mingw-w64 comdat ABI compatibility bug (https://github.com/Alexpux/MINGW-packages/issues/1677#issuecomment-394906508, also below) for i686, it shows we don't use the right section names:

$ cat a.cpp
inline int foo(int a, int b) { return a + b; }
int bar(void);
int main() { return foo(1, 2) + bar(); }

$ cat b.cpp
inline int foo(int a, int b) { return a + b; }
int bar() { return foo(3, 4); }

$ gcc -m32 a.cpp -c -o a.o && clang --target=i686-w64-windows-gnu -c b.cpp -o b.o

$ dumpbin a.o | grep text
34 .text
10 .text$_Z3fooii

$ dumpbin b.o | grep text
1F .text
1F .text$__Z3fooii

Clang adds the extra '_' for Windows C symbol mangling, but GCC does not.

A user emailed me directly to report that they were getting linker errors, but I have not been able to observe any problems caused by this mismatch.

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