This fixes a gap in the `overloadable` attribute support (K&R declared
functions would get mangled symbol names, but that name wouldn't be
represented in the debug info linkage name field for the function) and
in -funique-internal-linkage-names (this came up in review discussion on
D98799) where K&R static declarations would not get the uniqued linkage
names.
C functions may be declared and defined in different prototypes like below. This patch unifies the checks for mangling names in symbol linkage name emission and debug linkage name emission so that the two names are consistent.
static int go(int);
static int go(a) int a;
{
return a;
}
Test Plan:
Differential Revision: https://reviews.llvm.org/D98799
D96109 added support for unique internal linkage names for both internal
linkage functions and global variables. There was a lot of discussion on how to
get the demangling right for functions but I completely missed the point that
demanglers do not support suffixes for global vars. For example:
$ c++filt _ZL3foo
foo
$ c++filt _ZL3foo.uniq.123
_ZL3foo.uniq.123
The demangling for functions works as expected.
I am not sure of the impact of this. I don't understand how debuggers and other
tools depend on the correctness of global variable demangling so I am
pre-emptively disabling it until we can get the demangling support added.
Importantly, uniquefying global variables is not needed right now as we do not
do profile attribution to global vars based on sampling. It was added for
completeness and so this feature is not exactly missed.
Differential Revision: https://reviews.llvm.org/D98392
The option -funique-internal-linkage-names was added in D73307 and D78243 as a
LLVM early pass to insert a unique suffix to internal linkage functions and
vars. The unique suffix was the hash of the module path. However, we found
that this can be done more cleanly in clang early and the fixes that need to
be done later can be completely avoided. The fixes in particular are trying
to modify the DW_AT_linkage_name and finding the right place to insert the
pass.
This patch ressurects the original implementation proposed in D73307 which
was reviewed and then ditched in favor of the pass based approach.
Differential Revision: https://reviews.llvm.org/D96109
David Blaikie