Add an option to directly specify where the msvc toolchain lives for
clang-cl and avoid unwanted file and registry probes.
Differential revision: https://reviews.llvm.org/D85998
Some compiler-rt tests check for the presence of the compiler accepting
-fno-lto to add that flag. Otherwise some tests don't link due to
-flto mismatch between compiling and linking.
$ cmake ... -DLLVM_ENABLE_LTO=Thin ...
$ ninja projects/compiler-rt/lib/sanitizer_common/tests/Sanitizer-x86_64-Test.exe
previously failed, now links.
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D85252
Summary:
-debug-info-kind=constructor reduces the amount of class debug info that
is emitted; this patch switches to using this as the default.
Constructor homing emits the complete type info for a class only when the
constructor is emitted, so it is expected that there will be some classes that
are not defined in the debug info anymore because they are never constructed,
and we shouldn't need debug info for these classes.
I compared the PDB files for clang, and there are 273 class types that are defined with `=limited`
but not with `=constructor` (out of ~60,000 total class types).
We've looked at a number of the types that are no longer defined with =constructor. The vast
majority of cases are something like class A is used as a parameter in a member function of
some other class B, which is emitted. But the function that uses class A is never called, and class A
is never constructed, and therefore isn't emitted in the debug info.
Bug: https://bugs.llvm.org/show_bug.cgi?id=46537
Subscribers: aprantl, cfe-commits, lldb-commits
Tags: #clang, #lldb
Differential Revision: https://reviews.llvm.org/D79147
Making -g[no-]column-info opt out reduces the length of a typical CC1 command line.
Additionally, in a non-debug compile, we won't see -dwarf-column-info.
Prior to this change, for a few compiler-rt libraries such as ubsan and
the profile library, Clang would embed "-defaultlib:path/to/rt-arch.lib"
into the .drective section of every object compiled with
-finstr-profile-generate or -fsanitize=ubsan as appropriate.
These paths assume that the link step will run from the same working
directory as the compile step. There is also evidence that sometimes the
paths become absolute, such as when clang is run from a different drive
letter from the current working directory. This is fragile, and I'd like
to get away from having paths embedded in the object if possible. Long
ago it was suggested that we use this for ASan, and apparently I felt
the same way back then:
https://reviews.llvm.org/D4428#56536
This is also consistent with how all other autolinking usage works for
PS4, Mac, and Windows: they all use basenames, not paths.
To keep things working for people using the standard GCC driver
workflow, the driver now adds the resource directory to the linker
library search path when it calls the linker. This is enough to make
check-ubsan pass, and seems like a generally good thing.
Users that invoke the linker directly (most clang-cl users) will have to
add clang's resource library directory to their linker search path in
their build system. I'm not sure where I can document this. Ideally I'd
also do it in the MSBuild files, but I can't figure out where they go.
I'd like to start with this for now.
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D65543
This flag is like /showIncludes, but it only includes user headers and
omits system headers (similar to MD and MMD). The motivation is that
projects that already track system includes though other means can use
this flag to get consistent behavior on Windows and non-Windows, and it
saves tools that output /showIncludes output (e.g. ninja) some work.
implementation-wise, this makes `HeaderIncludesCallback` honor the
existing `IncludeSystemHeaders` bit, and changes the three clients of
`HeaderIncludesCallback` (`/showIncludes`, `-H`, `CC_PRINT_HEADERS=1`)
to pass `-sys-header-deps` to set that bit -- except for
`/showIncludes:user`, which doesn't pass it.
Differential Revision: https://reviews.llvm.org/D75093
All 130+ f_Group flags that take an argument allow it after a '=',
except for fdebug-complation-dir. Add a Joined<> alias so that
it behaves consistently with all the other f_Group flags.
(Keep the old Separate flag for backwards compat.)
This matches https://gcc.gnu.org/onlinedocs/gcc/AArch64-Options.html
> -momit-leaf-frame-pointer
> -mno-omit-leaf-frame-pointer
>
> Omit or keep the frame pointer in leaf functions. The former behavior is the default.
-mno-omit-leaf-frame-pointer is currently a no-op because
TargetOptions::DisableFramePointerElim is only considered for non-leaf
functions.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D71167
Summary:
A new function pass (Transforms/CFGuard/CFGuard.cpp) inserts CFGuard checks on
indirect function calls, using either the check mechanism (X86, ARM, AArch64) or
or the dispatch mechanism (X86-64). The check mechanism requires a new calling
convention for the supported targets. The dispatch mechanism adds the target as
an operand bundle, which is processed by SelectionDAG. Another pass
(CodeGen/CFGuardLongjmp.cpp) identifies and emits valid longjmp targets, as
required by /guard:cf. This feature is enabled using the `cfguard` CC1 option.
Reviewers: thakis, rnk, theraven, pcc
Subscribers: ychen, hans, metalcanine, dmajor, tomrittervg, alex, mehdi_amini, mgorny, javed.absar, kristof.beyls, hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65761
These were added to the MS docs in
85b9b6967e
and are supposedly available in VS 2019 16.4 (though my 2019 Preview,
version 16.4.0-pre.1.0 don't seem to have them.)
llvm-svn: 373887
This broke compiling some ASan tests with never versions of MSVC/the Win
SDK, see https://crbug.com/996675
> MSVC 2017 update 3 (_MSC_VER 1911) enables /Zc:twoPhase by default, and
> so should clang-cl:
> https://docs.microsoft.com/en-us/cpp/build/reference/zc-twophase
>
> clang-cl takes the MSVC version it emulates from the -fmsc-version flag,
> or if that's not passed it tries to check what the installed version of
> MSVC is and uses that, and failing that it uses a default version that's
> currently 1911. So this changes the default if no -fmsc-version flag is
> passed and no installed MSVC is detected. (It also changes the default
> if -fmsc-version is passed or MSVC is detected, and either indicates
> _MSC_VER >= 1911.)
>
> As mentioned in the MSDN article, the Windows SDK header files in
> version 10.0.15063.0 (Creators Update or Redstone 2) and earlier
> versions do not work correctly with /Zc:twoPhase. If you need to use
> these old SDKs with a new clang-cl, explicitly pass /Zc:twoPhase- to get
> the old behavior.
>
> Fixes PR43032.
>
> Differential Revision: https://reviews.llvm.org/D66394
llvm-svn: 369647
MSVC 2017 update 3 (_MSC_VER 1911) enables /Zc:twoPhase by default, and
so should clang-cl:
https://docs.microsoft.com/en-us/cpp/build/reference/zc-twophase
clang-cl takes the MSVC version it emulates from the -fmsc-version flag,
or if that's not passed it tries to check what the installed version of
MSVC is and uses that, and failing that it uses a default version that's
currently 1911. So this changes the default if no -fmsc-version flag is
passed and no installed MSVC is detected. (It also changes the default
if -fmsc-version is passed or MSVC is detected, and either indicates
_MSC_VER >= 1911.)
As mentioned in the MSDN article, the Windows SDK header files in
version 10.0.15063.0 (Creators Update or Redstone 2) and earlier
versions do not work correctly with /Zc:twoPhase. If you need to use
these old SDKs with a new clang-cl, explicitly pass /Zc:twoPhase- to get
the old behavior.
Fixes PR43032.
Differential Revision: https://reviews.llvm.org/D66394
llvm-svn: 369402
with '-mframe-pointer'
After D56351 and D64294, frame pointer handling is migrated to tri-state
(all, non-leaf, none) in clang driver and on the function attribute.
This patch makes the frame pointer handling cc1 option tri-state.
Reviewers: chandlerc, rnk, t.p.northover, MaskRay
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D56353
llvm-svn: 366645
Use a tri-state enum to represent shouldUseFramePointer() and
shouldUseLeafFramePointer().
This simplifies the logic and fixes PR9825:
-fno-omit-frame-pointer doesn't imply -mno-omit-leaf-frame-pointer.
and PR24003:
/Oy- /O2 should not omit leaf frame pointer: this matches MSVC x86-32.
(/Oy- is a no-op on MSVC x86-64.)
and:
when CC1 option -mdisable-fp-elim if absent, -momit-leaf-frame-pointer
can also be omitted.
The new behavior matches GCC:
-fomit-frame-pointer wins over -mno-omit-leaf-frame-pointer
-fno-omit-frame-pointer loses out to -momit-leaf-frame-pointer
The behavior makes lots of sense. We have 4 states:
- 00) leaf retained, non-leaf retained
- 01) leaf retained, non-leaf omitted (this is invalid)
- 10) leaf omitted, non-leaf retained (what -momit-leaf-frame-pointer was designed for)
- 11) leaf omitted, non-leaf omitted
"omit" options taking precedence over "no-omit" options is the only way
to make 3 valid states representable with -f(no-)?omit-frame-pointer and
-m(no-)?omit-leaf-pointer.
Reviewed By: ychen
Differential Revision: https://reviews.llvm.org/D64294
llvm-svn: 365860
With this, `clang-cl /source-charset:utf-16 test.cc` now prints `invalid
value 'utf-16' in '/source-charset:utf-16'` instead of `invalid value
'utf-16' in '-finput-charset=utf-16'` before, and several other clang-cl
flags produce much less confusing output as well.
Fixes PR29106.
Since an arg and its alias can have different arg types (joined vs not)
and different values (because of AliasArgs<>), I chose to give the Alias
its own Arg object. For convenience, I just store the alias directly in
the unaliased arg – there aren't many arg objects at runtime, so that
seems ok.
Finally, I changed Arg::getAsString() to use the alias's representation
if it's present – that function was already documented as being the
suitable function for diagnostics, and most callers already used it for
diagnostics.
Implementation-wise, Arg::accept() previously used to parse things as
the unaliased option. The core of that switch is now extracted into a
new function acceptInternal() which parses as the _aliased_ option, and
the previously-intermingled unaliasing is now done as an explicit step
afterwards.
(This also changes one place in lld that didn't use getAsString() for
diagnostics, so that that one place now also prints the flag as the user
wrote it, not as it looks after it went through unaliasing.)
Differential Revision: https://reviews.llvm.org/D64253
llvm-svn: 365413
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
Our limited debug info optimizations are breaking down at DLL
boundaries, so we're going to evaluate the size impact of these
settings, and possibly change the default.
Users should be able to override our settings, though.
llvm-svn: 281056
Checking for the type of the command line tokenizer should not be the criteria to enable support for the CL environment variable, this change checks that we are in clang-cl mode instead.
Differential Revision: https://reviews.llvm.org/D23503
llvm-svn: 280702
Clang always assumes that files are utf-8. If an invalidly encoded character is
used in an identifier, clang always errors. If it's used in a character
literal, clang warns Winvalid-source-encoding (on by default). Clang never
checks the encoding of things in comments (adding this seems like a nice
feature if it doesn't impact performance).
For cl.exe /utf-8 (which enables /validate-charset), if a bad character is used
in an identifier, it emits both an error and a warning. If it's used in a
literal or a comment, it emits a warning.
So mapping /validate-charset to -Winvalid-source-encoding seems like a fairly
decent fit.
https://reviews.llvm.org/D23945
llvm-svn: 279872
Clang tracks only start columns, not start-end ranges. CodeView allows for that, but the VS debugger doesn't handle anything less than a complete range well--it either highlights the wrong part of a statement or truncates source lines in the assembly view. It's better to have no column information at all.
So by default, we'll omit the column information for CodeView targeting Windows.
Since the column info is still useful for sanitizers, I've promoted -gcolumn-info (and -gno-column-info) to a CoreOption and added a couple tests to make sure that works for clang-cl.
Differential Revision: https://reviews.llvm.org/D23720
llvm-svn: 279765
/Brepro means we want reproducible builds, i.e. we _don't_ want the timestamp
that's needed to be compatible with the incremental linker.
https://reviews.llvm.org/D23805
llvm-svn: 279555
clang already treats all inputs as utf-8. Warn if anything but utf-8 is passed.
Do this by mapping source-charset to finput-charset, which already behaves like
this. Slightly tweak finput-charset to accept "utf-8" case-insensitively. This
matches gcc's and cl.exe's behavior, and IANA says that character set names are
case-insensitive.
https://reviews.llvm.org/D23807
llvm-svn: 279531
It's surprising that you have to pass /Z7 in addition to -gcodeview to
get debug info. The sanitizer runtime, for example, expects that if the
compiler supports the -gline-tables-only flag, then it will emit debug
info.
llvm-svn: 278139
MASM (ML.exe and ML64.exe) and older versions of MSVC (CL.exe) support a
flag called /Zd which is more-or-less -gline-tables-only.
It seems nicer to support this flag instead of exposing
-gline-tables-only.
llvm-svn: 274991
Add support for /Ob1 (and equivalent -finline-hint-functions), which enable
inlining only for functions marked inline, either explicitly (via inline
keyword, for example), or implicitly (function definition in class body,
for example).
This works by enabling inlining pass, and adding noinline attribute to
every function not marked inline.
Patch by Rudy Pons <rudy.pons@ilod.org>!
Differential Revision: http://reviews.llvm.org/D20647
llvm-svn: 273440
-finline-functions and /Ob2 are currently ignored by Clang. The only way to
enable inlining is to use the global O flags, which also enable other options,
or to emit LLVM bitcode using Clang, then running opt by hand with the inline
pass.
This patch allows to simply use the -finline-functions flag (same as GCC) or
/Ob2 in clang-cl mode to enable inlining without other optimizations.
This is the first patch of a serie to improve support for the /Ob flags.
Patch by Rudy Pons <rudy.pons@ilod.org>!
Differential Revision: http://reviews.llvm.org/D20576
llvm-svn: 270609
-fms-compatibility-version was defaulting to 18 (VS 2013), which is a pain if your environment is pointing to version 19 (VS 2015) libraries.
If cl.exe can be found, this patch uses its version number as the default instead. It re-uses the existing code to find the Visual Studio binaries folder and WinAPI methods to check its version. You can still explicitly specify a compatibility version on the command line. If you don't have cl.exe, this should be a no-op and you'll get the old default of 18.
This affected the tests, which assumed that if you didn't specific a version, that it would default to 18, but this won't be true for all machines. So a couple test cases had to be eliminated and a couple others had to be tweaked to allow for various outputs.
Addresses: https://llvm.org/bugs/show_bug.cgi?id=27215
Differential Revision: http://reviews.llvm.org/D20136
llvm-svn: 269515
r260990 exposed -isystem in clang-cl. -isystem adds a directory to the front of
the system include search path. The idea was to use this to point to a hermetic
msvc install, but as it turns out this doesn't work: -isystem then adds the
hermetic headers in front of clang's builtin headers, and clang's headers that
are supposed to wrap msvc headers (say, stdarg.h) aren't picked up at all
anymore.
So revert that, and instead expose -imsvc which works as if the passed
directory was part of %INCLUDE%: The header is treated as a system header, but
it is searched after clang's lib/Header headers.
Fixes half of PRPR26751.
llvm-svn: 266108
Alexandre Ganea