This is similar to what we had until bug 1278456 removed them when we dropped
support for older libstdc++, but for a different symbol.
--HG--
extra : rebase_source : 641fc6c86c8f47e3dbd752bc20056f61646541a7
That the wrapper implementation works has been verified by creating a
dummy program such as:
$ cat test.cc
#include <thread>
int main() {
std::thread([]() {
printf("foo\n");
}).join();
return 0;
}
And compiling it with and without the hack:
$ g++ -fno-rtti -o test test.cc -lpthread
$ objdump -TC test | grep UND.*GLIBCXX_3.4.22
0000000000000000 DF *UND* 0000000000000000 GLIBCXX_3.4.22 std:🧵:_State::~_State()
0000000000000000 DF *UND* 0000000000000000 GLIBCXX_3.4.22 std:🧵:_M_start_thread(std::unique_ptr<std:🧵:_State, std::default_delete<std:🧵:_State> >, void (*)())
$ ./test
foo
$ g++ -fno-rtti -o test test.cc $objdir/build/unix/stdc++compat/stdc++compat.o -lpthread
$ objdump -TC test | grep UND.*GLIBCXX_3.4.22
$ ./test
foo
--HG--
extra : rebase_source : 53ca8e2d0424eaeb539d50510c441c8a3252c819
In some cases, we can end up linking some things with
--static-libstdc++. The notable (only?) example of that is for the
clang-plugin, and that happens because it gets some of its flags from
llvm-config, which contains --static-libstdc++ because clang itself is
built that way.
When that happens, the combination of --static-libstdc++ and
stdc++compat breaks the build because they have conflicting symbols,
which is very much by design.
There are two ways out of this:
- avoiding either -static-libstdc++ or stdc++compat
- work around the symbol conflicts
The former is not totally reliable ; we'd have to accurately determine
if we're in a potentially conflicting case, and remove one of the two in
that case, and while we can do that for the cases we explicitly know
about, that's not future-proof, and might fail just as much in the
future.
So we go with the latter. The way we do this is by defining all the
std++compat symbols weak, such that at link time, they're overridden by
any symbol with the same name. When building with -static-libstdc++,
libstdc++.a provides those symbols so the linker eliminates the weak
ones. When not building with -static-libstdc++, the linker keeps the
symbols from stdc++compat. That last assertion is validated by the
long-standing CHECK_STDCXX test that we run when linking shared
libraries and programs.
That still leaves the symbols weak in the final shared
libraries/programs, which is a change from the current setup, but
shouldn't cause problems because when using versions of libstdc++.so
that do provide those symbols, it's fine to use the libstdc++.so version
anyways.
This removes the unnecessary setting of c-basic-offset from all
python-mode files.
This was automatically generated using
perl -pi -e 's/; *c-basic-offset: *[0-9]+//'
... on the affected files.
The bulk of these files are moz.build files but there a few others as
well.
MozReview-Commit-ID: 2pPf3DEiZqx
--HG--
extra : rebase_source : 0a7dcac80b924174a2c429b093791148ea6ac204
As part of this move, HOST_NSPR_MDCPUCFG needed to be changed to get the quoting right.
--HG--
extra : commitid : J26MhSiPq9g
extra : rebase_source : 81c5b98371042803741ddace8d01b0097757dff3
Incidentally, this makes the build fail because stdc++compat.o then appears
twice on the libxul linkage command line. This, in turn, is because
widget/xremoteclient creates both a program and an intermediate library for
libxul. The Program() template adds stdc++compat to the directory data,
which ends up being added to libxul as well. The same kind of issue arises
when linking the gtest-enabled libxul.
While eventually we'll be able to avoid those problems, it's not the case
yet, so work around the issue by making expand-libs skip .desc files that
appear multiple times.
Chris Manchester
Mike Hommey
Lee Salzman
Tom Tromey
Ted Mielczarek
Ehsan Akhgari
Frank Wein
Cykesiopka
Joey Armstrong
Brian O'Keefe
Mike Shal
Kyle Machulis
Rafael Ávila de Espíndola
Gregory Szorc
Justin Lebar
Randell Jesup
Gervase Markham