This is a new attempt for bringing TSan libdispatch support to Linux.
The main issue with the last patch (https://reviews.llvm.org/D53171) was
that we want to avoid building a separate library.
The updated plan is as follows:
1) Hide libdispatch support behind a flag: true on Darwin, false
elsewhere. If flag is specified, assume that libdispatch header and
-flbocks is available for building. This way we can directly include
the libdispatch header and rely on blocks runtime for our
implementation.
2) Optionally/weakly intercept libdispatch API functions.
This patch accomplishes 1). It compiles (without the flag enabled) on
Linux. Follow-up patches will provide 2) and enabling of tests on Linux.
Reviewed By: dvyukov
Differential Revision: https://reviews.llvm.org/D58935
llvm-svn: 355538
Building compiler-rt standalone outside of the main llvm
tree is supported, and in this case, the llvm cmake modules
are unavailable. (And even if they are available, it requires
including LLVMProcessSources.cmake, which currently isn't
included.)
This fixes building compiler-rt standalone with MSVC/clang-cl.
Differential Revision: https://reviews.llvm.org/D58767
llvm-svn: 355237
This changes add_custom_libcxx to also build libcxxabi and merges
the two into a static and hermetic library.
There are multiple advantages:
1) The resulting libFuzzer doesn't expose C++ internals and looks
like a plain C library.
2) We don't have to manually link in libstdc++ to provide cxxabi.
3) The sanitizer tests cannot interfere with an installed version
of libc++.so in LD_LIBRARY_PATH.
Differential Revision: https://reviews.llvm.org/D58013
llvm-svn: 354212
Add missed value "libcxxabi" and introduce SANITIZER_TEST_CXX for linking
unit tests. This needs to be a full C++ library and cannot be libcxxabi.
Recommit r354132 which I reverted in r354153 because it broke a sanitizer
bot. This was because of the "fixes" for pthread linking, so I've removed
these changes.
Differential Revision: https://reviews.llvm.org/D58012
llvm-svn: 354198
Add missed value "libcxxabi" and introduce SANITIZER_TEST_CXX for linking
unit tests. This needs to be a full C++ library and cannot be libcxxabi.
Differential Revision: https://reviews.llvm.org/D58012
llvm-svn: 354132
NDK r19 includes a sysroot that can be used directly by the compiler
without creating a standalone toolchain, so we just need a handful
of flags to point Clang there.
Differential Revision: https://reviews.llvm.org/D57733
llvm-svn: 353139
Rather than guessing whether to use static or shared version of
unwinder and c++abi when using linking against the in-tree versions,
provide a CMake option to control this.
Differential Revision: https://reviews.llvm.org/D57492
llvm-svn: 352723
Having libc++ checked out doesn't necessarily mean it should be built;
for example, the same source tree might be used for multiple build
configurations, and libc++ might not build in some of those
configurations. Add an option to compiler-rt's build to disable building
libc++. This defaults to ON, so it shouldn't change any existing build
configurations.
Differential Revision: https://reviews.llvm.org/D56479
llvm-svn: 351117
Summary:
This essentially reverts r337010 since it breaks UBSan, which is used
for a few platform libraries. The "-z global" flag is now added for
Scudo as well. The only other sanitizer shared libraries are for asan
and hwasan, which have also been reinstated to use the global flag.
Reviewers: cryptoad, eugenis
Reviewed By: cryptoad
Subscribers: kubamracek, mgorny, delcypher, #sanitizers, nickdesaulniers, chh, kongyi, pirama, llvm-commits
Differential Revision: https://reviews.llvm.org/D52770
llvm-svn: 343599
The CMAKE_<LANG>_ARCHIVE_FINISH rule doesn't need to be cleared for Darwin
static libraries. Avoid resetting the variables in the SIP case. If
CMAKE_RANLIB is cached, then CMake's Ninja generator will invoke ranlib during
installation, not due to the CMAKE_<LANG>_ARCHIVE_FINISH rule.
llvm-svn: 342511
When building static fat libraries, we need to ensure that we use libtool rather
than llvm-ar to create the library. Duplicate the rules from LLVM to ensure
that we correctly build the fat libraries when building compiler-rt standalone.
This also requires that we duplicate the workaround for the `DYLD_LIBRARY_PATH`
for SIP. Additionally, ensure that we set the `CMAKE_*_ARCHIVE_FINISH` variable
to ensure that we do not try to use `ranlib` on that target.
llvm-svn: 342425
Summary:
The idea behind this change is to allow sanitization of libc. We are prototyping on Bionic,
but the tool interface will be general enough (or at least generalizable) to support any other libc.
When libc depends on libclang_rt.hwasan, the latter can not interpose libc functions.
In fact, majority of interceptors become unnecessary when libc code is instrumented.
This change gets rid of most hwasan interceptors and provides interface for libc to notify
hwasan about thread creation and destruction events. Some interceptors (pthread_create)
are kept under #ifdef to enable testing with uninstrumented libc. They are expressed in
terms of the new libc interface.
The new cmake switch, COMPILER_RT_HWASAN_WITH_INTERCEPTORS, ON by default, builds testing
version of the library with the aforementioned pthread_create interceptor.
With the OFF setting, the library becomes more of a libc plugin.
Reviewers: vitalybuka, kcc, jfb
Subscribers: srhines, kubamracek, mgorny, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D50922
llvm-svn: 340216
compiler-rt CMake build currently tries to parse the triple and then
put it back together, but doing so inherently tricky, and doing so
from CMake is just crazy and currently doesn't handle triples that
have more than three components. Fortunatelly, the CMake really only
needs the architecture part, which is typically the first component,
to construct variants for other architectures. This means we can keep
the rest of the triple as is and avoid the parsing altogether.
Differential Revision: https://reviews.llvm.org/D50548
llvm-svn: 339701
This changes the name and the type to what it was prior to r333037
which matches the name of the flag used in other runtimes: libc++,
libc++abi and libunwind. We don't need the type to be a string since
there's only binary choice between libgcc and compiler-rt unlike in
the case of C++ library where there're multiple options.
Differential Revision: https://reviews.llvm.org/D49325
llvm-svn: 337116
These are not necessarily correct, just because Clang is configured
to use libc++ or compiler-rt as defaults doesn't mean that the host
compiler uses these as defaults as well. A more correct solution
would be to test the host compiler to check what the default actually
is as attempted in D46857.
Part of PR-38025.
Differential Revision: https://reviews.llvm.org/D49272
llvm-svn: 337033
Summary:
Use `-Wl,-z,global` for all Sanitizer shared libraries on
Android. We want them to be in the global group
(https://android.googlesource.com/platform/bionic/+/master/android-changes-for-ndk-developers.md#changes-to-library-search-order)
to avoid any alloc/dealloc mismatch between the libc allocator & said library.
`audioserver` was one of the binary that exhibited the problem with Scudo,
this seems to fix it.
[edited for accuracy]
Reviewers: eugenis, alekseyshl
Reviewed By: eugenis
Subscribers: kubamracek, srhines, mgorny, delcypher, #sanitizers, llvm-commits
Differential Revision: https://reviews.llvm.org/D49198
llvm-svn: 337010
Summary:
A prior refactoring accidentally dropped the case for using libc++abi as
the out-of-tree C++ runtime library for sanitizers. This patch restores
that functionality, which is used by Android, which can't depend on the
full libc++ for these libraries.
Reviewers: phosek, EricWF
Reviewed By: phosek
Subscribers: meikeb, kongyi, chh, mgorny, delcypher, llvm-commits, #sanitizers, pirama
Differential Revision: https://reviews.llvm.org/D49157
llvm-svn: 336749
This change adds a support for multiarch style runtimes layout, so in
addition to the existing layout where runtimes get installed to:
lib/clang/$version/lib/$os
Clang now allows runtimes to be installed to:
lib/clang/$version/$target/lib
This also includes libc++, libc++abi and libunwind; today those are
assumed to be in Clang library directory built for host, with the
new layout it is possible to install libc++, libc++abi and libunwind
into the runtime directory built for different targets.
The use of new layout is enabled by setting the
LLVM_ENABLE_RUNTIME_TARGET_DIR CMake variable and is supported by both
projects and runtimes layouts. The runtimes CMake build has been further
modified to use the new layout when building runtimes for multiple
targets.
Differential Revision: https://reviews.llvm.org/D45604
llvm-svn: 335809
build with an IDE (e.g. Xcode) as the generator.
Previously the global `USE_FOLDERS` property wasn't set in standalone
builds leading to existing settings of FOLDER not being respected.
In addition to this there were several targets that appeared at the top
level that were not interesting and clustered up the view. These have
been changed to be displayed in "Compiler-RT Misc".
Now when an Xcode project is generated from a standalone compiler-rt
build the project navigator is much less cluttered. The interesting
libraries should appear in "Compiler-RT Libraries" in the IDE.
Differential Revision: https://reviews.llvm.org/D48378
llvm-svn: 335728
Use compiler-rt builtins when selected as default Clang rtlib and avoid
explicitly passing -rtlib= flag to avoid the "argument unused during
compilation" warning.
This is a partial alternative to D47094 that does not rely on compiler
runtime checks.
Differential Revision: https://reviews.llvm.org/D47115
llvm-svn: 333037
Use libc++ when selected as default Clang stdlib and avoid checking
C++ compiler when using the in-tree version of libc++.
This is a partial alternative to D47094 that does not rely on compiler
runtime checks.
Differential Revision: https://reviews.llvm.org/D47100
llvm-svn: 333010
Rather then requiring the user to specify runtime the compiler
runtime and C++ standard library, or trying to guess them which is
error-prone, use auto-detection by parsing the compiler link output.
Differential Revision: https://reviews.llvm.org/D46857
llvm-svn: 332683
The source being compiled is plain C, but using .cc extension forces it
to be compiled as C++ which requires a working C++ compiler including
C++ library which may not be the case when we're building compiler-rt
together with libcxx as part of runtimes build.
Differential Revision: https://reviews.llvm.org/D47031
llvm-svn: 332679
Fuchsia is no longer treated as UNIX which means we need to explicitly
enable building of shared versions of runtimes.
Differential Revision: https://reviews.llvm.org/D46609
llvm-svn: 331922
Clang-cl supports the -gline-tables-only flag, so we were going down
that path. Honestly, we should just go ahead and enable full codeview
support.
llvm-svn: 330989
This expands the CMake check to handle both statically and dynamically
linked version of libc++abi and libunwind and matches the implemnetation
used elsewhere in LLVM.
Differential Revision: https://reviews.llvm.org/D45242
llvm-svn: 329205
Summary:
For some reason CMake can't find the `append` macro if LLVM is built separately and imported via `LLVM_CONFIG_PATH`.
Patch by Loo Rong Jie
Reviewers: rnk, vitalybuka
Reviewed By: rnk, vitalybuka
Subscribers: dberris, mgorny, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D43458
llvm-svn: 327876
This also slightly refactors the code that's checking the directory
presence which allows eliminating one unnecessary variable.
Differential Revision: https://reviews.llvm.org/D40637
llvm-svn: 320446
Per beanz, building compiler-rt standalone is a pretty important use
case, so the comment is very out of date.
Differential Revision: https://reviews.llvm.org/D40740
llvm-svn: 319570
Allow user to override shadow scale in compiler_rt by passing
-DCOMPILER_RT_ASAN_SHADOW_SCALE=n to CMake. Propagate the override
shadow scale value via a compiler define to compiler-rt and asan
tests. Tests will use the define to partially disable unsupported
tests. Set "-mllvm -asan-mapping-scale=<n>" for compiler_rt tests.
Differential Revision: https://reviews.llvm.org/D39469
llvm-svn: 318038
Make it possible to control building profile runtime separately from
other options. Before r313549, the profile runtime building was
controlled along with sanitizers. However, since that commit it is built
unconditionally which results in multiple builds for people building
different runtimes separately.
Differential Revision: https://reviews.llvm.org/D38441
llvm-svn: 314646
This is a resubmission of r313270. It broke standalone builds of
compiler-rt because we were not correctly generating the llvm-lit
script in the standalone build directory.
The fixes incorporated here attempt to find llvm/utils/llvm-lit
from the source tree returned by llvm-config. If present, it
will generate llvm-lit into the output directory. Regardless,
the user can specify -DLLVM_EXTERNAL_LIT to point to a specific
lit.py on their file system. This supports the use case of
someone installing lit via a package manager. If it cannot find
a source tree, and -DLLVM_EXTERNAL_LIT is either unspecified or
invalid, then we print a warning that tests will not be able
to run.
Differential Revision: https://reviews.llvm.org/D37756
llvm-svn: 313407
This was originally broken by r258744 which introduced a weak reference
from ubsan to ubsan_cxx. This reference does not work directly on
Windows because COFF has no direct concept of weak symbols. The fix is
to use /alternatename to create a weak external reference to ubsan_cxx.
Also fix the definition (and the name, so that we drop cached values)
of the cmake flag that controls whether to build ubsan_cxx. Now the
user-controllable flag is always on, and we turn it off internally
depending on whether we support building it.
Differential Revision: https://reviews.llvm.org/D37882
llvm-svn: 313391
This was intended to be a generic CMake solution to a problem
shared across several projects. It turns out it doesn't interact
very well certain CMake configurations, and furthermore the
"problem" is actually not a problem, as the problematic code
is never executed to begin with. So this really isn't solving
anything.
llvm-svn: 313191
Fuchsia's lowest API layer has been renamed from Magenta to Zircon.
Patch by Roland McGrath
Differential Revision: https://reviews.llvm.org/D37770
llvm-svn: 313106
Some projects need to add conditional dependencies on other projects.
compiler-rt is already doing this, and I attempted to add this to
debuginfo-tests when I ran into the ordering problem, that you can't
conditionally add a dependency unless that dependency's CMakeLists.txt
has already been run (which would allow you to say if (TARGET foo).
The solution to this seems to be to determine very early on the entire
set of projects which is enabled. This is complicated by the fact that
there are multiple ways to enable projects, and different tree layouts
(e.g. mono-repo, out of -tree, external, etc). This patch attempts to
centralize all of this into one place, and then updates compiler-rt to
demonstrate as a proof of concept how this can simplify code.
Differential Revision: https://reviews.llvm.org/D37637
llvm-svn: 313091
Resulting library binaries will be named libclang_rt.fuzzer*, and will
be placed in Clang toolchain, allowing redistribution.
Differential Revision: https://reviews.llvm.org/D36908
llvm-svn: 311407
Summary: This is to support Android where libc++abi is part of libc++.
Reviewers: srhines, EricWF
Subscribers: dberris, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D36640
llvm-svn: 310769
Summary:
Define a build-time configuration option for the XRay runtime to
determine whether the archive will add an entry to the `.preinit_array`
section of the binary. We also allow for initializing the XRay data
structures with an explicit call to __xray_init(). This allows us to
give users the capability to initialize the XRay data structures on
demand.
This can allow us to start porting XRay to platforms where
`.preinit_array` isn't a supported section. It also allows us to limit
the effects of XRay in the initialization sequence for applications that
are sensitive to this kind of interference (i.e. large binaries) or
those that want to package XRay control in libraries.
Future changes should allow us to build two different library archives
for the XRay runtime, and allow clang users to determine which version
to link.
Reviewers: dblaikie, kpw, pelikan
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D36080
llvm-svn: 309909
Android uses libgcc name even for shared library unlike other platforms
which use libgcc_s. Furthemore, Android libstdc++ has a dependency on
libdl. These need to be handled while performing CMake checks.
Differential Revision: https://reviews.llvm.org/D36035
llvm-svn: 309638
This change adds sanitizer support for LLVM's libunwind and libc++abi
as an alternative to libstdc++. This allows using the in tree version
of libunwind and libc++abi which is useful when building a toolchain
for different target.
Differential Revision: https://reviews.llvm.org/D34501
llvm-svn: 309362
This change adds support for compiler-rt builtins as an alternative
compiler runtime to libgcc.
Differential Revision: https://reviews.llvm.org/D35165
llvm-svn: 309361
This patch addresses two issues:
Most of the time, hacks with `if/else` in order to get support for
multi-configuration builds are superfluous.
The variable `CMAKE_CFG_INTDIR` was created precisely for this purpose: it
expands to `.` on all single-configuration builds, and to a configuration
name otherwise.
The `if/else` hacks for the library name generation should also not be
done, as CMake has `TARGET_FILE` generator expression precisely for this
purpose, as it expands to the exact filename of the resulting target.
Differential Revision: https://reviews.llvm.org/D35952
llvm-svn: 309341
This change adds sanitizer support for LLVM's libunwind and libc++abi
as an alternative to libstdc++. This allows using the in tree version
of libunwind and libc++abi which is useful when building a toolchain
for different target.
Differential Revision: https://reviews.llvm.org/D34501
llvm-svn: 309074
This change adds support for compiler-rt builtins as an alternative
compiler runtime to libgcc.
Differential Revision: https://reviews.llvm.org/D35165
llvm-svn: 309060
Summary:
Since r298413, the NEW behavior of the CMake policy CMP0056 is followed.
However, it is only effective after the call to cmake_minimum_required.
This causes CMAKE_EXE_LINKER_FLAGS etc. to be unused when CMake tries to
check compilers for languages specified in the 'project' declaration.
Set cmake_minimum_required(VERSION) at the top of the file and ahead of
the project declaration.
Reviewers: beanz
Subscribers: mgorny, srhines, llvm-commits
Differential Revision: https://reviews.llvm.org/D34282
llvm-svn: 305593
Disable building enable_execute_stack.c for targets that do not have
support for mprotect().
Differential Revision: https://reviews.llvm.org/D33018
llvm-svn: 302680
On Darwin, we're having multiple issues with using -fomit-frame-pointer in the AddressSanitizer and ThreadSanitizer runtimes, so we're actually not using -fomit-frame-pointer in the our builds of the sanitizer dylibs. This patch just pushes our internal change upstream.
The issues are usually with debuggers, profilers and other tools that unwind the stack (crash reporter), which are often simply not able to get a stack trace. And crashlogs that don't contain a stack trace are a huge problem.
Differential Revision: https://reviews.llvm.org/D31376
llvm-svn: 298859
Summary: check_cxx_compiler_flag and check_library_exists could fail because they ignored CMAKE_EXE_LINKER_FLAGS and therefore would always fail to produce executables. Cmake policy CMP0056 fixes this, but was explicitly set to OLD in our CMakeLists because it caused problems with test_target_arch. This change sets the policy to NEW to fix the problem with the compiler and library tests, and temporarily clears CMAKE_EXE_LINKER_FLAGS inside test_target_arch to emulate the old behavior there. This allows, for example, LTO builds that require lld to succeed.
Reviewers: davidxl, beanz
Reviewed By: beanz
Subscribers: fjricci, dberris, mgorny, mehdi_amini, tejohnson, rnk, llvm-commits
Differential Revision: https://reviews.llvm.org/D31098
llvm-svn: 298413
Revert "Fix sanitizer tests with LLVM_TOOL_LLD_BUILD=OFF."
Revert "[asan] Remove gc-sections test with bfd."
Revert "[asan] Disable globals-gc test with ld.bfd."
Revert "[asan] Fix dead stripping of globals on Linux (compiler-rt)"
OOM in gold linker.
llvm-svn: 298287
Summary:
For a reason that hasn't been investigated for lack of powerpc knowledge and
hardware, -fno-function-sections is required for the Sanitizers to work
properly on powerpc64le. Without, the function-sections-are-bad test fails on
that architecture (and that architecture only).
This patch re-enables the flag in the powerpc64le cflags.
I have to admit I am not entirely sure if my way is the proper way to do this,
so if anyone has a better way, I'll be happy to oblige.
Reviewers: kcc, eugenis
Reviewed By: eugenis
Subscribers: nemanjai, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D29285
llvm-svn: 293558
Summary:
-fno-function-sections was added as a default Sanitizer common cflag with
https://reviews.llvm.org/rL200683, the reasoning behind was that things would
break if linked with --gc-sections.
This appears to not be necessary anymore, as tests pass without, including
function-sections-are-bad.cc. There is a large benefit to having
function-sections when dealing with static libraries in terms of size and
dependencies that go away with --gc-sections.
Reviewers: kcc, eugenis
Reviewed By: eugenis
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D29132
llvm-svn: 293220
Summary:
We put empty object files in archives, which causes MSVC's linker to
complain about these objects not defining any previously undefined
symbols. Since we do it on purpose, this only creates noise during
the build process. This patch causes us to suppress the warnings.
Reviewers: rnk, samsonov
Subscribers: dberris, mgorny
Differential Revision: https://reviews.llvm.org/D28262
llvm-svn: 291011
Sanitizers are intentionally not including system headers and often declare slightly different function prototypes, which is incompatible with -fmodules and -fcxx-modules. Let’s simply exclude compiler-rt from using -fmodules.
Differential Revision: https://reviews.llvm.org/D25230
llvm-svn: 283658
Summary: This flag doesn't make sense on Windows systems.
Reviewers: beanz, kubabrecka, compnerd
Subscribers: dberris, llvm-commits, beanz
Differential Revision: https://reviews.llvm.org/D24320
llvm-svn: 280953
Summary:
Allow for use of cxxabi to be disabled from cmake.
This will make sanitizers usable when c++ abi is unavailable.
Reviewers: pcc, rnk, samsonov, beanz, compnerd
Subscribers: llvm-commits, compnerd, dberris
Differential Revision: https://reviews.llvm.org/D23639
llvm-svn: 279451
When compiler-rt's CMake is not directly invoked, it will currently not call
project() and thus ASM will not be enabled.
We also don't need to put the .S files through the C compiler then.
Differential Revision: https://reviews.llvm.org/D23656
llvm-svn: 279215
Summary: This will allow for the sanitizers to be used when c++ abi is unavailable.
Reviewers: samsonov, beanz, pcc, rnk
Subscribers: llvm-commits, kubabrecka, compnerd, dberris
Differential Revision: https://reviews.llvm.org/D23376
llvm-svn: 278848
Summary: This will allow for the sanitizers to be used when c++ abi is unavailable.
Reviewers: samsonov, beanz, pcc, rnk
Subscribers: llvm-commits, kubabrecka, compnerd, dberris
Differential Revision: https://reviews.llvm.org/D23376
llvm-svn: 278772
Summary: This will allow for the sanitizers to be used when c++ abi is unavailable.
Reviewers: samsonov, beanz, pcc, rnk
Subscribers: llvm-commits, kubabrecka, compnerd, dberris
Differential Revision: https://reviews.llvm.org/D23376
llvm-svn: 278764
/Zi creates a separate PDB that we're supposed to pass along with our
sanitizer libraries, but the object library compilation rules aren't set
up to handle that. Rather than set that up, put the debug info in the
object files the way every other platform does it with /Z7.
llvm-svn: 277406
This reverts commit 23240d8de38c79220a888f645a1f4b686bfb87c6.
Broke the build because the build bots haven't gotten the latest config
from zorg yet.
llvm-svn: 276847
Summary:
This is a fixed-up version of D21612, to address failure identified post-commit.
Original commit description:
This patch implements the initialisation and patching routines for the XRay runtime, along with the necessary trampolines for function entry/exit handling. For now we only define the basic hooks for allowing an implementation to define a handler that gets run on function entry/exit. We expose a minimal API for controlling the behaviour of the runtime (patching, cleanup, and setting the handler to invoke when instrumenting).
Fixes include:
- Gating XRay build to only Linux x86_64 and with the right dependencies in case it is the only library being built
- Including <cstddef> to fix std::size_t issue
Reviewers: kcc, rnk, echristo
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D22611
llvm-svn: 276251
Should fix the Windows buildbots, and maybe some other non-Linux Unix
bots too.
XRay currently depends on sanitizer_common, so associate it with the
"build sanitizers" option and remove the option for separately
controlling the XRay build.
llvm-svn: 276124
Summary:
This patch implements the initialisation and patching routines for the XRay runtime, along with the necessary trampolines for function entry/exit handling. For now we only define the basic hooks for allowing an implementation to define a handler that gets run on function entry/exit. We expose a minimal API for controlling the behaviour of the runtime (patching, cleanup, and setting the handler to invoke when instrumenting).
Depends on D19904
Reviewers: echristo, kcc, rnk
Subscribers: rnk, mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D21612
llvm-svn: 276117
The triple must be parsed in base-config-ix.cmake.
Otherwise, the cmake variable ANDROID won't be set and this
will confuse cmake to build unsupported targets targeted for
android.
Diferential revision: http://reviews.llvm.org/D21474
llvm-svn: 273914
Julian Lettner