These symbols need to be external (MSVC tools error out if a weak
external points at a symbol that isn't external; this was tried before
but had to be reverted in bc5b7217dc,
and this was originally explicitly fixed in
732eeaf2a9).
If multiple object files have weak symbols with defaults, their
defaults could cause linker errors due to duplicate definitions,
unless the names of the defaults are unique.
GNU binutils handles this by appending the name of another symbol
from the same object file to the name of the default symbol. Try
to implement something similar; before writing the object file,
locate a symbol that should have a unique name and use the name of
that one for making the weak defaults unique.
Differential Revision: https://reviews.llvm.org/D75989
If we have references to the same extern_weak in multiple objects,
all of them would generate external symbols with the same name. Make
them static to avoid duplicate definitions; nothing should need to
refer to this symbol outside of the current object.
GCC/binutils seems to handle the same by not using a fixed string
for the ".default" suffix, but instead using the name of some other
defined external symbol from the same object (which is supposed to
be unique among objects unless there's other duplicate definitions).
Differential Revision: https://reviews.llvm.org/D71711
The weak alias should have the characteristics set to
`IMAGE_EXTERN_WEAK_SEARCH_ALIAS` to indicate that the weak external here
is a symbol alias and that the symbol is aliased to a locally defined
symbol. We were previously setting the characteristics to
`IMAGE_EXTERN_WEAK_SEARCH_LIBRARY` which indicates that the symbol
should be looked for in the libraries.
llvm-svn: 364370
-t is --symbols in llvm-readobj but --section-details (unimplemented) in readelf.
The confusing option should not be used since we aim for improving
compatibility.
Keep just one llvm-readobj -t use case in test/tools/llvm-readobj/symbols.test
llvm-svn: 359661
We were creating a weak external that tried to reference a static symbol. That
would always fail to link with link.exe.
We now create an external symbol in the same position as the local and refer
to that. This works with link.exe and matches what gas does.
llvm-svn: 270906
Martin Storsjö