The flag is useful when wanting to create .o files that are independent
from the absolute path to the build directory. -fdebug-prefix-map= can
be used to the same effect, but it requires putting the absolute path
to the build directory on the build command line, so it still requires
the build command line to be dependent on the absolute path of the build
directory. With this flag, "-fdebug-compilation-dir ." makes it so that
both debug info and the compile command itself are independent of the
absolute path of the build directory, which is good for build
determinism (in the sense that the build is independent of which
directory it happens in) and for caching compile results.
(The tradeoff is that the debugger needs explicit configuration to know
the build directory. See also http://dwarfstd.org/ShowIssue.php?issue=171130.2)
Differential Revision: https://reviews.llvm.org/D63387
llvm-svn: 363548
Update the `cl` emulation to support the `/Zc:char8_t[-]?` options as per the
MSVC 2019.1 toolset. These are aliases for `-fchar8_t` and `-fno-char8_t`.
llvm-svn: 361859
This is needed so lld-link can find clang_rt.profile when self hosting
on Windows with PGO. Using clang-cl as a linker knows to add the library
but self hosting, using -DCMAKE_LINKER=<...>/lld-link.exe doesn't.
Differential Revision: https://reviews.llvm.org/D61742
llvm-svn: 360674
We will now warn about such options being unused,
which is better than the current
"no such file or directory: '/d2foo'" errors.
Note that we can still handle specific flags separately,
e.g. we were already ignoring /d2FastFail and /d2Zi+
llvm-svn: 355682
The /AI flag is for #using directives, which I don't think we support.
This is consistent with how the /I flag is handled by MSVC. Add a test
for it.
Differential Revision: https://reviews.llvm.org/D57189
llvm-svn: 352119
Summary: /Zc:dllexportInlines with /fallback may cause unexpected linker error. It is better to disallow compile rather than warn for this combination.
Reviewers: hans, thakis
Reviewed By: hans
Subscribers: cfe-commits, llvm-commits
Differential Revision: https://reviews.llvm.org/D54426
llvm-svn: 346733
The clang-cl driver disables access to command line options outside of the
"Core" and "CLOption" sets of command line arguments. This filtering makes it
impossible to pass arguments that are interpreted by the clang driver and not
by either 'cc1' (the frontend) or one of the other tools invoked by the driver.
An example driver-level flag is the '-fno-slp-vectorize' flag, which is
processed by the driver in Clang::ConstructJob and used to set the cc1 flag
"-vectorize-slp". There is no negative cc1 flag or -mllvm flag, so it is not
currently possible to disable the SLP vectorizer from the clang-cl driver.
This change introduces the "/clang:" argument that is available when the
driver mode is set to CL compatibility. This option works similarly to the
"-Xclang" option, except that the option values are processed by the clang
driver rather than by 'cc1'. An example usage is:
clang-cl /clang:-fno-slp-vectorize /O2 test.c
Another example shows how "/clang:" can be used to pass a flag where there is
a conflict between a clang-cl compat option and an overlapping clang driver
option:
clang-cl /MD /clang:-MD /clang:-MF /clang:test_dep_file.dep test.c
In the previous example, the unprefixed /MD selects the DLL version of the msvc
CRT, while the prefixed -MD flag and the -MF flags are used to create a make
dependency file for included headers.
One note about flag ordering: the /clang: flags are concatenated to the end of
the argument list, so in cases where the last flag wins, the /clang: flags
will be chosen regardless of their order relative to other flags on the driver
command line.
Patch by Neeraj K. Singh!
Differential revision: https://reviews.llvm.org/D53457
llvm-svn: 346393
Summary:
This CL adds /Zc:DllexportInlines flag to clang-cl.
When Zc:DllexportInlines- is specified, inline class member function is not exported if the function does not have local static variables.
By not exporting inline function, code for those functions are not generated and that reduces both compile time and obj size. Also this flag does not import inline functions from dllimported class if the function does not have local static variables.
On my 24C48T windows10 machine, build performance of chrome target in chromium repository is like below.
These stats are come with 'target_cpu="x86" enable_nacl = false is_component_build=true dcheck_always_on=true` build config and applied
* https://chromium-review.googlesource.com/c/chromium/src/+/1212379
* https://chromium-review.googlesource.com/c/v8/v8/+/1186017
Below stats were taken with this patch applied on a05115cd4c
| config | build time | speedup | build dir size |
| with patch, PCH on, debug | 1h10m0s | x1.13 | 35.6GB |
| without patch, PCH on, debug | 1h19m17s | | 49.0GB |
| with patch, PCH off, debug | 1h15m45s | x1.16 | 33.7GB |
| without patch, PCH off, debug | 1h28m10s | | 52.3GB |
| with patch, PCH on, release | 1h13m13s | x1.22 | 26.2GB |
| without patch, PCH on, release | 1h29m57s | | 37.5GB |
| with patch, PCH off, release | 1h23m38s | x1.32 | 23.7GB |
| without patch, PCH off, release | 1h50m50s | | 38.7GB |
This patch reduced obj size and the number of exported symbols largely, that improved link time too.
e.g. link time stats of blink_core.dll become like below
| | cold disk cache | warm disk cache |
| with patch, PCH on, debug | 71s | 30s |
| without patch, PCH on, debug | 111s | 48s |
This patch's implementation is based on Nico Weber's patch. I modified to support static local variable, added tests and took stats.
Bug: https://bugs.llvm.org/show_bug.cgi?id=33628
Reviewers: hans, thakis, rnk, javed.absar
Reviewed By: hans
Subscribers: kristof.beyls, smeenai, dschuff, probinson, cfe-commits, eraman
Differential Revision: https://reviews.llvm.org/D51340
llvm-svn: 346069
This change allows usage of -march when using the clang-cl driver. This is similar to MSVC's /arch; however -march can target precisely all supported CPUs, while /arch has a more restricted set.
Differential Revision: https://reviews.llvm.org/D51806
llvm-svn: 341847
This extension emits the guard cf table without inserting the
instrumentation. Currently that's what clang-cl does with /guard:cf
anyway, but this allows a user to request that explicitly.
Differential Revision: https://reviews.llvm.org/D50513
llvm-svn: 339420
-no-canonical-prefixes is a weird flag: In gcc, it controls whether realpath()
is called on the path of the driver binary. It's needed to support some
usecases where gcc is symlinked to, see
https://gcc.gnu.org/ml/gcc/2011-01/msg00429.html for some background.
In clang, the resource dir is found relative to the compiler binary, and
without -no-canonical-prefixes that's an absolute path. For clang, the main use
case for -no-canonical-prefixes is to make the -resource-dir path added by the
driver relative instead of absolute. Making it relative seems like the better
default, but since neither clang not gcc have -canonical-prefixes without no-
which makes changing the default tricky, and since some symlink behaviors do
depend on the realpath() call at least for gcc, just expose
-no-canonical-prefixes in clang-cl mode.
Alternatively we could default to no-canonical-prefix-mode for clang-cl since
it's less likely to be used in symlinked scenarios, but since you already need
to about -no-canonical-prefixes for the non-clang-cl bits of your build, not
hooking this of driver mode seems better to me.
https://reviews.llvm.org/D47480
llvm-svn: 333761
This reverts commit SVN r331666.
It was afterwards pointed out in https://reviews.llvm.org/D46520
that #line directives lose information about what parts come from a
system header. That means the result of -E usually won't compile,
since Windows headers are typically full of warnings and
default-error warnings.
llvm-svn: 331858
This replicates 'cl.exe' behavior and allows for both preprocessor output and
dependency information to be extraced with a single compiler invocation.
This is especially useful for compiler caching with tools like Mozilla's sccache.
See: https://github.com/mozilla/sccache/issues/246
Patch By: fxb
Differential Revision: https://reviews.llvm.org/D46394
llvm-svn: 331533
This is for consistency with lld-link, see https://reviews.llvm.org/D38972
Also give --version a help text so it shows up in --help / /? output (for
both clang-cl and regular clang).
llvm-svn: 316335
It sounds like MSVC is adding support for two-phase name lookup in a
future version, enabled by this flag (see bug).
Differential Revision: https://reviews.llvm.org/D32138
llvm-svn: 300501
Summary: This enables LTO to be used with the clang-cl frontend.
Reviewers: rnk, hans
Reviewed By: hans
Subscribers: pcc, cfe-commits, mehdi_amini, Prazek
Differential Revision: https://reviews.llvm.org/D30239
llvm-svn: 296373
Both on Mac and Windows, it's common to have a 'Users' directory in the
root of the filesystem, so one might specify a filename as
'/Users/me/myfile.c'. clang-cl (as well as MSVC's cl.exe) will interpret
that as invoking the '/U' option, which is probably not what the user
wanted. Add a warning about this.
Differential Revision: https://reviews.llvm.org/D29198
llvm-svn: 293305
- Don't break using '-mllvm -disable-llvm-optzns' (yet).
- Don't add support for '-mllvm -disable-llvm-passes'.
This is important for LLVM 4 as we haven't yet really told folks this is
coming. I'll add release notes about this.
I've also added some explicit testing of this so its more obvious what
is happening here.
llvm-svn: 291850
Summary:
This change adds support for the -fno-delayed-template-parsing option in
clang-cl.exe. This allows developers using clang-cl.exe to opt out of
emulation of MSVC's non-conformant template instantiation implementation
while continuing to use clang-cl.exe for its emulation of cl.exe
command-line options. The default behavior of clang-cl.exe
(-fdelayed-template-parsing) is unchanged.
The MSVC Standard Library implementation uses clang-cl.exe with this
switch in its tests to ensure that the library headers work on compilers
with the conformant two-phase-lookup behavior.
Reviewers: majnemer, cfe-commits, DaveBartolomeo
Differential Revision: https://reviews.llvm.org/D22275
llvm-svn: 290990
Much to my surprise, '-disable-llvm-optzns' which I thought was the
magical flag I wanted to get at the raw LLVM IR coming out of Clang
deosn't do that. It still runs some passes over the IR. I don't want
that, I really want the *raw* IR coming out of Clang and I strongly
suspect everyone else using it is in the same camp.
There is actually a flag that does what I want that I didn't know about
called '-disable-llvm-passes'. I suspect many others don't know about it
either. It both does what I want and is much simpler.
This removes the confusing version and makes that spelling of the flag
an alias for '-disable-llvm-passes'. I've also moved everything in Clang
to use the 'passes' spelling as it seems both more accurate (*all* LLVM
passes are disabled, not just optimizations) and much easier to remember
and spell correctly.
This is part of simplifying how Clang drives LLVM to make it cleaner to
wire up to the new pass manager.
Differential Revision: https://reviews.llvm.org/D28047
llvm-svn: 290392
Summary: Makes -fprofile-instr-generate and -fprofile-instr-use work
with clang-cl so that profile-guided optimization can be used.
Differential Revision: https://reviews.llvm.org/D27086
llvm-svn: 288230
We could hook up /GL as an alias for -flto, but that might be
confusing, as clang-cl in that mode would not be drop-in compatible
with cl.exe /GL, as it requires the linker to be lld.
Exposing -flto seems like a less confusing way to expose this
functionality.
llvm-svn: 283255
Nico Weber