On Sun, 22 Oct 2017, Tamar Christina wrote:
Actually..
This may not be the right fix. The regression I am trying to fix is a duplicate
symbols error on _wassert when
linking both mscvrt and mingwex. But I now see that:
commit 1035bed24e833ea5eb487c78f4f350ea48f31e8b
Author: Martin Storsjö <[email protected]>
Date: Fri Sep 29 12:42:59 2017 +0300
crt: More strictly flag functions in the unified msvcrt.def.in
Now the output from the unified msvcrt.def.in should be almost identical
to what it was before, except for some new *_dbg and __p_* functions.
The functions that were included for 32 and 64 bit x86 in the unification
were originally believed to be harmless, but some of them turned out to
be function that we have compatibility fallbacks for, that were missed
when libmsvcrt.a suddenly started exporting them. This broke compatibility
with XP in some cases.
Signed-off-by: Martin Storsjö <[email protected]>
added the change
-_wassert
+F_ARM_ANY(_wassert)
and I don't know why... it's there on x86 as well.
The issure you're seeing, is that when you've built with the absolutely
latest master version that includes this commit?
Because if the issue you're seeing is duplicate symbols between msvcrt and
mingwex, it doesn't sound like you have this commit, this commit actually
would fix it.
To elaborate; before commit 2146d75d7fd027118fe267f2a8fb139bcab6a9b8, all
architectures had separate def files for msvcrt.dll. Neither lib32 nor
lib64 had _wassert at all, only libarm32. In
2146d75d7fd027118fe267f2a8fb139bcab6a9b8 and
0360917119ad3f09635d75103b6dba859cfe0c93 I merged all of them into one,
but I did a mistake of exposing more functions than before - I assumed
that this wouldn't be an issue except for people. This caused issues where
the built binaries wouldn't run on XP any longer (msvcrt.a has got
compatibility fallbacks for some functions, but exposing them in the def
file ended up linking directly to the function in msvcrt.dll.
In 1035bed24e833ea5eb487c78f4f350ea48f31e8b I tried to fix this mistake;
after this commit, libmsvcrt.a should contains pretty much exactly what
it did before I started touching it, trying to fix what I broke.
For _wassert; indeed, all versions of msvcrt.dll even back to XP contains
this function. But since mingw-w64 has got their own version in
libmingwex, we shouldn't expose the function in the def file. The reason
it's exposed for arm is only that I tried to mimic exactly what the def
files had before I started touching it; in case someone tries to do the
same as you for arm, they would probably end up with the same issue, so we
should probably remove that function from there as well.
I'm dubious about this patch as all of these F_ARM_ANY'ed values are also
available on x86, this is causing an annoying linking problem. As I want to
link to the
msvcrt functions first and only mingwex for the extensions it provides.
As for why a lot of other functions are flagged F_ARM_ANY; they might be
functions that exist in modern versions of msvcrt.dll but not in the
baseline XP version. Since windows on arm (windows phone) only exists
corresponding to windows 8 and newer, it's ok to expose all functions that
existed in that baseline version for arm, while we want to hide them (and
fall back on compatibility wrappers) for 32 bit x86 where XP compatibility
still is maintained.
So in short, after all the commits I did on libmsvcrt.a lately, it should
now be pretty much exactly as it was before - these functions were omitted
for one reason or another (some for more or less tricky compatibility
workarounds) earlier in the project history. It's just the arm side that
is newer that so far exports much more, but with more use, actually might
end up tweaked closer to the x86 versions.
// Martin
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