The x86 linux builds originally were performed in x86 build environment.
That was a long time ago. Since then, they moved to x86-64 hosts with
x86 headers and libraries. But for reasons that might have to do with
the build system not really supporting cross-compilation nicely back
then, the build is still explicitly passing both --host and --target,
making those builds non-cross builds.
Since the toolchains used to build are for x86-64, the fact that --host
is for x86 actually prevents enabling the clang plugin, so we need to
turn these builds in actual cross builds if we want to enable the clang
plugin.
The x86 linux builds originally were performed in x86 build environment.
That was a long time ago. Since then, they moved to x86-64 hosts with
x86 headers and libraries. But for reasons that might have to do with
the build system not really supporting cross-compilation nicely back
then, the build is still explicitly passing both --host and --target,
making those builds non-cross builds.
Since the toolchains used to build are for x86-64, the fact that --host
is for x86 actually prevents enabling the clang plugin, so we need to
turn these builds in actual cross builds if we want to enable the clang
plugin.
This setup seems to work well enough to enable me to link
HOST_SIMPLE_PROGRAMS with an AArch64-cross setup. Necessary library
paths are passed to the linker via -LIBPATH and HOST_LDFLAGS rather than
letting MSVC fish them out of the environment. The change to
HOST_SIMPLE_PROGRAMS to pass HOST_LDFLAGS was necessary for this to
work, in addition to the HOST_LINKER changes.
-Wtautological-overlap-compare is an opt-in warning added in clang 3.5. It warns about overlapping comparisons that are always true or false, such as:
if (x > 4 || x < 10) {} // warning! always true
int b = x < 2 && x > 5; // warning! always false
return x > 4 || x < 10; // warning! always true
https://clang.llvm.org/docs/DiagnosticsReference.html#wtautological-overlap-compare
There are currently no -Wtautological-overlap-compare warnings in mozilla-central.
Differential Revision: https://phabricator.services.mozilla.com/D3477
--HG--
extra : rebase_source : e6aa211a338633e5fb7507b3a8f341709d72d6c9
This opt-in warning catches bugs where a constructor modifies a constructor parameter that shadows member variable name. The code probably intended to change the member variable value, not the paramter. There are currently no -Wshadow-field-in-constructor warnings in mozilla-central.
https://clang.llvm.org/docs/DiagnosticsReference.html#wshadow-field-in-constructor-modified
Differential Revision: https://phabricator.services.mozilla.com/D3822
--HG--
extra : rebase_source : 604ff90e036d536955db41351ee9ee97e8424d92
extra : intermediate-source : 712f538afc160f4efae2383130727edbd1dd70f6
extra : source : 300fff9a58515c7cac0647afc9ccc0e69bc8c5cb
-Wfloat-overflow-conversion detects when a constant floating point value is converted to an integer type and will overflow the target type.
https://clang.llvm.org/docs/DiagnosticsReference.html#wfloat-overflow-conversion
-Wfloat-zero-conversion detects when a non-zero floating point value is converted to a zero integer value.
https://clang.llvm.org/docs/DiagnosticsReference.html#wfloat-zero-conversion
There are currently no -Wfloat-overlap-conversion warnings in mozilla-central. There is one -Wfloat-zero-conversion warning in a webrtc test. It doesn't block enabling this check because the webrtc tests are not compiled with warnings-as-errors.
media/webrtc/trunk/webrtc/modules/audio_coding/audio_network_adaptor/frame_length_controller_unittest.cc:255:54 [-Wfloat-zero-conversion] implicit conversion from 'const float' to 'int' changes non-zero value from 0.045000002 to 0
We can't enable all -Wfloat-conversion warnings (for any implicit conversion of a floating-point number into an integer) because there are currently over 1400 warnings. I spot checked a few of these -Wfloat-conversion warnings. I didn't find any obvious bugs, but there is some suspicious code, such as implicit conversions of floats to bools.
Differential Revision: https://phabricator.services.mozilla.com/D3476
--HG--
extra : rebase_source : 589be9e593749c7000b1f89ca155e4f95a487f8f
Warn about C++ constructs whose meaning change in C++2a.
https://clang.llvm.org/docs/DiagnosticsReference.html#wc-2a-compat
So far the only -Wc++2a-compat check that I know of is for valid pre-C++2a code that inadvertently parses as C++2a's new <=> "spaceship" comparison operator. `f<&A::operator<=>();` is an example of a warning reported for a real project on GitHub. That code can be rewritten as `f< &operator<= >();`.
There are currently no -Wc++2a-compat warnings in mozilla-central.
Differential Revision: https://phabricator.services.mozilla.com/D3478
--HG--
extra : rebase_source : 4ec8147ad3fe2d1ef7c543d100c660a000385786
Our version check is removed as well, as the current required rustc version for
Firefox includes all features required to build with tup.
Differential Revision: https://phabricator.services.mozilla.com/D3847
--HG--
extra : moz-landing-system : lando
When valgrind prints out backtraces, it prints raw addresses and symbol
names, but that doesn't help find the exact code that caused the errors,
because we don't know where the libraries are loaded.
With --sym-offsets=yes, it adds the offset from the symbol, which allows
to find the relevant code in the binary.
For some reason, clang 6 crashes with a stack overflow on PGO + LTO on
Linux 64 bits. Clang 7 doesn't, but has other problems.
After some bisecting, I found the following:
- r322684 is the first revision that is broken on the release_60 branch.
- that revision is a cherry pick of r322313 from trunk, which is
similarly broken.
- trunk was fixed by r322325, which, funnily enough, predates when
r322313 was cherry-picked.
While the change from r322325 is relatively large, mixing multiple
different changes in a single commit, there also haven't been
significant changes to the same file on trunk since (one macro name
change, one documentation change, and a change related to debug info),
which would tend to indicate the change is not going to break anything,
or at least not more than upgrading to clang 7 would.
The exact part that fixes the issue could probably be found in this
large commit, but I didn't feel like digging into it further considering
the above.
In order to support operator==() for tagged enum, we have to bump the version to
0.6.2.
Differential Revision: https://phabricator.services.mozilla.com/D3932
--HG--
extra : moz-landing-system : lando
yasm doesn't support aarch64, and trying to use GNU as with an MSVC
build seems like sadness waiting to happen. Instead, we'll generate our
own assembly file that armasm64 will accept.
