This is a very basic toolchain. It supports cross-compiling Windows (primarily
inspired by the WoA target). It is meant to use clang with the LLVM IAS and a
binutils ld-compatible interface for the linker (eventually to be lld). It does
not perform any "standard" GCC lookup, nor does it perform any special
adjustments given that it is expected to be used in an environment where the
user is using MSVCRT (and as such Visual Studio headers) and the Windows SDK.
The primary runtime library is expected to be compiler-rt and the C++
implementation to be libc++.
It also expects that a sysroot has been setup given the usual Unix semantics
(standard C headers in /usr/include, all the import libraries available in
/usr/lib). It also expects that an entry point stub is present in /usr/lib
(crtbegin.obj for executables, crtbeginS.obj for shared libraries).
The entry point stub is responsible for running any GNU constructors.
llvm-svn: 220546
This renames the Windows toolchain to MSVCToolChain. This is a preparatory step
for adding a CrossWindowsToolChain which uses clang/libc++/(ld/lld) without the
standard GCC toolchain lookup. NFC.
llvm-svn: 220362
This fixes crash report generation when filenames have spaces. It also
removes an awkward workaround that quoted *some* arguments when
generating crash reports.
llvm-svn: 220307
This pushes the logic for generating a crash reproduction script
entirely into Command::Print, instead of Command doing half of the
work and then relying on textual substitution for the rest. This makes
this logic much easier to read and will simplify fixing a couple of
issues in this area.
llvm-svn: 220305
List the module cache we use for crashdumps as a tempfile. This
simplifies how we pick up this directory when generating the actual
crash diagnostic and removes some duplicate logic.
llvm-svn: 220241
In practice there's only ever one temporary output file when
generating a crashdump, but even if there were many iterating over
each and creating a duplicate run script for each one wouldn't make
very much sense.
This updates the behaviour to only generate the script once, based on
the first filename.
This should make it more reasonable to generate extra output files to
include in the crashdump going forward, so I've also added a FIXME to
look into doing just that with the extra module crashdump files.
llvm-svn: 220238
We currently use a null FailingCommand when generating crash reports
as an indication that the cause is FORCE_CLANG_DIAGNOSTICS_CRASH, the
environment variable that exists to test crash dumps. This means that
our tests don't actually cover real crashes at all, and adds a more
complicated code path that's only used in the tests.
Instead, we can have the driver synthesize that every command failed
and just call generateCompilationDiagnostics normally.
llvm-svn: 220234
There's probably never a good reason to iterate over unique_ptrs. This
lets us use range-for and say Job.foo instead of (*it)->foo in a few
places.
llvm-svn: 218938
Patch by Rafael Auler!
This patch addresses PR15171 and teaches Clang how to call other tools
with response files, when the command line exceeds system limits. This
is a problem for Windows systems, whose maximum command-line length is
32kb.
I introduce the concept of "response file support" for each Tool object.
A given Tool may have full support for response files (e.g. MSVC's
link.exe) or only support file names inside response files, but no flags
(e.g. Apple's ld64, as commented in PR15171), or no support at all (the
default case). Therefore, if you implement a toolchain in the clang
driver and you want clang to be able to use response files in your
tools, you must override a method (getReponseFileSupport()) to tell so.
I designed it to support different kinds of tools and
internationalisation needs:
- VS response files ( UTF-16 )
- GNU tools ( uses system's current code page, windows' legacy intl.
support, with escaped backslashes. On unix, fallback to UTF-8 )
- Clang itself ( UTF-16 on windows, UTF-8 on unix )
- ld64 response files ( only a limited file list, UTF-8 on unix )
With this design, I was able to test input file names with spaces and
international characters for Windows. When the linker input is large
enough, it creates a response file with the correct encoding. On a Mac,
to test ld64, I temporarily changed Clang's behavior to always use
response files regardless of the command size limit (avoiding using huge
command line inputs). I tested clang with the LLVM test suite (compiling
benchmarks) and it did fine.
Test Plan: A LIT test that tests proper response files support. This is
tricky, since, for Unix systems, we need a 2MB response file, otherwise
Clang will simply use regular arguments instead of a response file. To
do this, my LIT test generate the file on the fly by cloning many -DTEST
parameters until we have a 2MB file. I found out that processing 2MB of
arguments is pretty slow, it takes 1 minute using my notebook in a debug
build, or 10s in a Release build. Therefore, I also added "REQUIRES:
long_tests", so it will only run when the user wants to run long tests.
In the full discussion in
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20130408/171463.html,
Rafael Espindola discusses a proper way to test
llvm::sys::argumentsFitWithinSystemLimits(), and, there, Chandler
suggests to use 10 times the current system limit (20MB resp file), so
we guarantee that the system will always use response file, even if a
new linux comes up that can handle a few more bytes of arguments.
However, by testing with a 20MB resp file, the test takes long 8 minutes
just to perform a silly check to see if the driver will use a response
file. I found it to be unreasonable. Thus, I discarded this approach and
uses a 2MB response file, which should be enough.
Reviewers: asl, rafael, silvas
Reviewed By: silvas
Subscribers: silvas, rnk, thakis, cfe-commits
Differential Revision: http://reviews.llvm.org/D4897
llvm-svn: 217792
Test Plan: The patch includes a test case.
Reviewers: hansw
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D5338
llvm-svn: 217710
Summary:
cl.exe recognizes /o as a deprecated and undocumented option similar to
/Fe. This patch adds support for this option to clang-cl for /Fe, /Fo
and /Fi. It also ensures that the last option among /o and /F* wins,
if both specified.
This is required at least for building autoconf based software, since
autoconf uses -o to specify the executable output.
This fixes http://llvm.org/PR20894.
Test Plan: The patch includes automated tests.
Reviewers: rnk
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D5308
llvm-svn: 217615
actually different. Fixes a surprising link error with nodejs on rpi,
where armv6-netbsd-eabihf turned into armv5e-netbsd-eabihf, which
doesn't lacks the necessary VFP support.
llvm-svn: 217546
It hits a limit when we reach ActionList, which is used for dynamic
conditional ownership, so we lose type safety there.
This did expose at least one caller "lying" about ownership (passing
ownership to an Action, then updating the Action to specify that it
doesn't actually own the thing that was passed) - changing this to
unique_ptr just makes that oddity more obvious.
llvm-svn: 216713
This patch aims at fixing PR17239.
This bug happens because the /link (clang-cl.exe argument) is marked as
"consume all remaining arguments". However, when inside a response file,
/link should only consume all remaining arguments inside the response
file where it is located, not the entire command line after expansion.
The LLVM side of the patch will change the semantics of the
RemainingArgsClass kind to always consume only until the end of the
response file when the option originally came from a response file.
There are only two options in this class: dash dash (--) and /link.
This is the Clang side of the patch in http://reviews.llvm.org/D4899
Reviewered By: rafael, rnk
Differential Revision: http://reviews.llvm.org/D4900
Patch by Rafael Auler!
llvm-svn: 216281
Summary:
Adding remaining 2 cases handling:
* from x32 to 32 via -m32
* from x32 to 64 via -m64
Test Plan: linux-ld test updated
Reviewers: chandlerc, atanasyan
Subscribers: cfe-commits, zinovy.nis
Differential Revision: http://reviews.llvm.org/D4930
llvm-svn: 215899
This escapes any backslashes in the executable path and fixes an issue
with a trailing quote when the main file name had to be quoted during
printing.
It's impossible to test this without putting backslashes or quotes into
the executable path, so I didn't add automated tests.
The crash diagnostics are still only useful if you're using bash on
Windows, though. This should probably be writing a batch file instead.
llvm-svn: 214924
The main subtlety here is that the Darwin tools still need to be given "-arch
arm64" rather than "-arch aarch64". Fortunately this already goes via a custom
function to handle weird edge-cases in other architectures, and it tested.
I removed a few arm64_be tests because that really isn't an interesting thing
to worry about. No-one using big-endian is also referring to the target as
arm64 (at least as far as toolchains go). Mostly they date from when arm64 was
a separate target and we *did* need a parallel name simply to test it at all.
Now aarch64_be is sufficient.
llvm-svn: 213744
-mx32 flag setup target environment to GNUX32 and can be used for
other 32/64-bit triplets (i386-unknown-linux, x86_64-unknown-linux) to
turn on x32 mode. Compatible with GCC -mx32 flag.
Differential Revision: http://reviews.llvm.org/D4470
llvm-svn: 212817
It reverts commits as follows:
r211866: "Driver: use GNU::Link for the Generic_GCC toolchain"
r211895: "Replace GetProgramPath("ld") with GetLinkerPath()."
r211995: "Driver: add a cygwin linker tool"
llvm-svn: 211998
This adds a linker tool for the Windows cygwin environment. This linker
invocation is significantly different from the generic ld invocation. It
requires additional parameters as well as does not accept some normal
parameters. This should fix self-hosting on Cygwin.
llvm-svn: 211995
When we create a crashdump involving modules, we build a VFS to
reproduce the problem with. This updates the reproduction script to
use that VFS.
llvm-svn: 211876
It's more flexible and arguably better layering to set flags to modify
compiling for diagnostics in the CC1 job themselves, rather than
tweaking the driver flags and letting them propagate.
There is one visible change this causes: crash report files will now
get preprocessed names (.i and friends).
llvm-svn: 211411
This corrects long-standing misuses of LLVM's internal config.h.
In most cases the public llvm-config.h header was intended and we can now
remove the old hacks thanks to LLVM r210144.
The config.h header is private, won't be installed and should no longer be
included by clang or other modules.
llvm-svn: 210145
All callers were passing in "a.out" or garbage so a sensible default works fine
here as a cleanup.
This also brings about the possibility of adapting the value based on the
driver's compatibility mode in future.
The setting can still be changed via Driver::DefaultImageName as needed.
llvm-svn: 208926
This follows the LLVM change to canonicalise the Windows target triple
spellings. Rather than treating each Windows environment as a single entity,
the environments are now modelled properly as an environment. This is a
mechanical change to convert the triple use to reflect that change.
llvm-svn: 204978
In gcc using -Ofast forces linking of crtfastmath.o.
In the current clang crtfastmath.o is only linked when -ffast-math/-funsafe-math-optimizations passed. It can lead to performance issues, when using only -Ofast without explicit -ffast-math (I faced with it).
My patch fixes inconsistency with gcc behaviour and also introduces few tests on it.
Patch by Zinovy Nis!
Differential Revision: http://llvm-reviews.chandlerc.com/D3114
llvm-svn: 204742
that implicitly converts to 'bool' (such as pointers, and the first operand of
?:). Clean up issues found by this. Patch by Stephan Tolksdorf!
llvm-svn: 203735
This patch improves the support for picking Multilibs from gcc installations.
It also provides a better approximation for the flags '-print-multi-directory'
and '-print-multi-lib'.
This reverts r201203 (i.e. re-applying r201202 with small fixes in
unittests/CMakeLists.txtto make the build bots happy).
review: http://llvm-reviews.chandlerc.com/D2538
llvm-svn: 201205
This patch improves the support for picking Multilibs from gcc installations.
It also provides a better approximation for the flags '-print-multi-directory'
and '-print-multi-lib'.
review: http://llvm-reviews.chandlerc.com/D2538
llvm-svn: 201202
Use the verify hook rather than the compile hook to represent the
-verify-pch action, and move the exising --verify-debug-info action
into its own subclass of VerifyJobAction. Incidentally change the name
printed by -ccc-print-phases for --verify-debug-info.
llvm-svn: 200938
This option will:
- load the given pch file
- verify it is not out of date by stat'ing dependencies, and
- return 0 on success and non-zero on error
llvm-svn: 200884
Instead of dual-purposing a single flag, rename the driver option to
--verify-debug-info.
The frontend -verify option that enables diagnostic verification remains
unchanged except that it's now a pure CC1Option.
Both have been given proper help text.
llvm-svn: 199451
Previously we had bodged together some hacks mapping MachO embedded
targets (i.e. mainly ARM v6M and v7M) to the "*-*-darwin-eabi" triple.
This is incorrect in both details (they don't run Darwin and they're
not EABI in any real sense).
This commit appropriates the existing "MachO" environment for the
purpose instead.
llvm-svn: 199367
encodes the canonical rules for LLVM's style. I noticed this had drifted
quite a bit when cleaning up LLVM, so wanted to clean up Clang as well.
llvm-svn: 198686
This is a follow-up to r194907, which added a new -arch setting to make it
easier to specify AVX2 targets. The "-arch x86_64h" option needs to be passed
on to the linker, but it was getting canonicalized to x86_64 by the code
in getArchTypeForDarwinArchName.
llvm-svn: 198096
This commit adds the flag '-via-file-asm' to the clang driver. The
purpose of this flag is to have a way to test that clang can consume
the assembly code that it outputs. When passed this flag, clang will
generate a temporary file that contains the assembly output from the
compile step. This assembly file will then be consumed by either the
integrated assembler or the external assembler. To test that the
integrated assembler can consume its own output compile with:
$ clang -integrated-assembler -via-file-asm
Without the '-via-file-asm' flag, clang would directly create the
object file when using the integrated assembler. With the flag it
will first create the temporary assembly file and then read that
file and assemble it with the integrated assembler.
The flow is similar to -save-temps, except that it only effects
the assembly input and the temporary file is not saved.
llvm-svn: 196606
This is currently unused by any test. The code path would still be hit
by clang on ppc, but
* PPC has not been supported on current versions of OS X
* A port of current clang to older OS X on ppc should be using
toolchains::DarwinClang.
llvm-svn: 195585
The thread, memory, dataflow and function sanitizers are now diagnosed if
enabled explicitly on an unsupported platform. Unsupported sanitizers which
are enabled implicitly (as part of a larger group) are silently disabled. As a
side effect, this makes SanitizerArgs parsing toolchain-dependent (and thus
essentially reverts r188058), and moves SanitizerArgs ownership to ToolChain.
Differential Revision: http://llvm-reviews.chandlerc.com/D1990
llvm-svn: 193875
This adds support for outputing the assembly to a file during compilation.
It does this by changing the compilation pipeling to not use the integrated
assembler, and keep the intermediate assembler file.
Differential Revision: http://llvm-reviews.chandlerc.com/D1946
llvm-svn: 192902
This doesn't change a lot since clang still thinks it knows all of the
-f*, -m* and -W* options for example.
Other than the options clang explicitly claims to know, this fixes pr9701.
llvm-svn: 191249
I put in the warnings because MSVC has them, but I don't think they're very
useful.
Clang does not warn about overriding flags in general, e.g. it's perfectly
fine to have -fomit-frame-pointer followed by -fno-omit-frame-pointer.
We should focus on warning where things get confusing, such as with the
/TP and /TC options. In "clang-cl /TC a.c /TP b.cc", the user might not
realize that the /TP flag will apply to both files, and we warn about that.
Differential Revision: http://llvm-reviews.chandlerc.com/D1718
llvm-svn: 190964
Previously we would warn about unused arguments such as /MD when linking.
Clang already has logic to ignore compile-only options, e.g. for -D and -U.
This patch extends that to include clang-cl's compile-only options too.
Also, some clang-cl options should always be ignored. Doing this earlier
means they get ignored both for compilation and link-only invocations.
llvm-svn: 190825
This moves the code to Job.cpp, which seems like a more natural fit,
and replaces the "is this a JobList? is this a Command?" logic with
a virtual function call.
It also removes the code duplication between PrintJob and
PrintDiagnosticJob and simplifies the code a little.
There's no functionality change here, except that the Executable is
now always printed within quotes, whereas it would previously not be
quoted in crash reports, which I think was a bug.
Differential Revision: http://llvm-reviews.chandlerc.com/D1653
llvm-svn: 190620
This adds driver support for building DLLs (the /LD and /LDd flags).
It basically does two things: runtime selection and passing -dll and
-implib to the linker.
llvm-svn: 190428
We already use .obj as extension when the user provides a stem file
name (via /Fo), but were failing in the most basic case when the file
name is based on the input file.
llvm-svn: 190071
One step toward differentiating following two commands:
clang -O3 -flto a.c -c, and
clang -O3 -emit-llvm a.c
Thanks many awesome folks for clarifying things.
llvm-svn: 189148
Summary:
This change turns SanitizerArgs into high-level options
stored in the Driver, which are parsed lazily. This fixes an issue of multiple copies of the same diagnostic message produced by sanitizer arguments parser.
Reviewers: rsmith
Reviewed By: rsmith
CC: chandlerc, eugenis, cfe-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D1341
llvm-svn: 188660
The rationale for this change is to differentiate following two situations:
1) clang -c -emit-llvm a.c
2) clang -c -flto a.c
Reviewed by Eric Christopher. Thanks a lot!
llvm-svn: 188352
This adds support for the /link option, which forwards
subsequent arguments to the linker.
The test for this will only work when targetting win32.
Since that's the only target where clang-cl makes sense,
use that target by default.
Differential Revision: http://llvm-reviews.chandlerc.com/D1388
llvm-svn: 188331
Anything that comes after -- is treated as an input file. This
used to be handled automagically by the option parsing library,
but after LLVM r188314, we should handle it ourselves.
No functionality change.
llvm-svn: 188316
This implements support for the /Fo option, which is used
to set the filename or output dir for object files.
Differential Revision: http://llvm-reviews.chandlerc.com/D1302
llvm-svn: 187820
These are used to specify source files, and whether to treat source
files as C or C++.
Differential Revision: http://llvm-reviews.chandlerc.com/D1290
llvm-svn: 187760
This adds a few more clang-cl options. It also exposes two core clang
options to the clang-cl mode: we need to be able to claim --driver_mode
so it doesn't show up as unused in cl mode, and we need -### for tests.
Differential Revision: http://llvm-reviews.chandlerc.com/D1232
llvm-svn: 187527
on the system, and report it when running the driver in verbose mode.
Without this it is essentially impossible to understand why a particular
GCC toolchain is used by Clang for libstdc++, libgcc, etc.
This also required threading a hook through the toolchain layers for
a specific toolchain implementation to print custom information under
'clang -v'. The naming here isn't spectacular. Suggestions welcome.
llvm-svn: 187427
This establishes a new Flag in Options.td, which can be assigned to
options that should be made available in clang's cl.exe compatible
mode, and updates the Driver to make use of the flag.
(The whitespace change to CMakeLists forces the build to re-run CMake
and pick up the include dependency on the new .td file. This makes the
build work if someone moves backwards in commit history after this change.)
Differential Revision: http://llvm-reviews.chandlerc.com/D1215
llvm-svn: 187280
This patch provides basic support for powerpc64le as an LLVM target.
However, use of this target will not actually generate little-endian
code. Instead, use of the target will cause the correct little-endian
built-in defines to be generated, so that code that tests for
__LITTLE_ENDIAN__, for example, will be correctly parsed for
syntax-only testing. Code generation will otherwise be the same as
powerpc64 (big-endian), for now.
The patch leaves open the possibility of creating a little-endian
PowerPC64 back end, but there is no immediate intent to create such a
thing.
The new test case variant ensures that correct built-in defines for
little-endian code are generated.
llvm-svn: 187180
and add a new option --driver-mode= to control it explicitly.
The CCCIsCXX and CCCIsCPP flags were non-overlapping, i.e. there
are currently really three modes that Clang can run in: gcc, g++
or cpp, so it makes sense to represent them as an enum.
Having a command line flag to control it helps testing.
llvm-svn: 186605
The big changes are:
- Deleting Driver/(Arg|Opt)*
- Rewriting includes to llvm/Option/ and re-sorting
- 'using namespace llvm::opt' in clang::driver
- Fixing the autoconf build by adding option everywhere
As discussed in the review, this change includes using directives in
header files. I'll make follow up changes to remove those in favor of
name specifiers.
Reviewers: espindola
Differential Revision: http://llvm-reviews.chandlerc.com/D975
llvm-svn: 183989
This option is used to select a dynamic loader prefix to be used
at runtime. Currently this is implemented for the Linux toolchain.
Differential Revision: http://llvm-reviews.chandlerc.com/D851
llvm-svn: 182744
This option can be useful for end users who want to know why they
ended up with a ton of different variants of the "std" module in their
module cache. This problem should go away over time, as we reduce the
need for module variants, but it will never go away entirely.
llvm-svn: 178148
Changing -ccc-install-dir to affect cc1's resource-dir setting broke our
internal LNT tests. After discussing the situation with Jim, we've decided to
pursue an alternate approach. We really want the resource-dir to be located
relative to clang, even when using -ccc-install-dir, but we're going to
add a fallback setting for the libc++ headers if they don't exist alongside
the compiler.
llvm-svn: 177815
linker via --dynamic-list instead of using --export-dynamic. This reduces the
size of the dynamic symbol table, and thus of the binary (in some cases by up
to ~30%).
llvm-svn: 177783
-ccc-install-dir is supposed to cause the compiler to behave as-if it
were installed in the indicated location. It almost does, but misses
anything that's relying on the resource directory (libc++ header search,
in particular). The resource dir is resolved too early, before command
line args are handled.
The fix is simply to move handling of the resource dir until after we
know if a -ccc-install-dir is present.
rdar://13402696
llvm-svn: 176894
subsequent commands from being executed.
The diagnostics generation isn't designed for this use case, so add a note to
fix this in the very near future. For now, just generated the diagnostics for
the first failing command.
Part of rdar://12984531
llvm-svn: 173825
produce a note for that diagnostic either with a different DiagnosticEngine or
after calling DiagnosticEngine::Reset(). That didn't make any sense, and did the
wrong thing if the original diagnostic was suppressed.
llvm-svn: 170636
paths
- Inherit from Linux rather than ToolChain
- Override AddClangSystemIncludeArgs and AddClangCXXStdlibIncludeArgs
to properly set include paths.
llvm-svn: 169495
uncovered.
This required manually correcting all of the incorrect main-module
headers I could find, and running the new llvm/utils/sort_includes.py
script over the files.
I also manually added quite a few missing headers that were uncovered by
shuffling the order or moving headers up to be main-module-headers.
llvm-svn: 169237
diagnostics script.
This addresses the FIXME pertaining to quoted arguments. We also delineate
between those flags that have an argument (e.g., -D macro, -MF file) and
those that do not (e.g., -M, -MM, -MG). Finally, we add the -dwarf-debug-flags
to the list of flags to be removed.
rdar://12329974
llvm-svn: 167152
is not a directory, Driver::GetProgramPath() routine does not try to append
the program name as a "path component" to it. It just joins the "prefix" with
the program name and checks the resulting path existence.
The patch reviewed by Rafael Espindola.
llvm-svn: 167114
we had the -ccc-clang-cxx and -ccc-no-clang-cxx options to force them
on or off for testing.
Clang c++ support is now production quality and these options are dead.
llvm-svn: 166986
Each option has a set of prefixes. When matching an argument such as
-funroll-loops. First the leading - is removed as it is a prefix. Then
a lower_bound search for "funroll-loops" is done against the option table by
option name. From there each option prefix + option name combination is tested
against the argument.
This allows us to support Microsoft style options where both / and - are valid
prefixes. It also simplifies the cases we already have where options come in
both - and -- forms. Almost every option for gnu-ld happens to have this form.
llvm-svn: 166444
clang itself. This dates back to clang's early days and while it looks like
some of it is still used (for kext for example), other parts are probably dead.
Remove the -ccc-clang-archs option and associated code. I don't think there
is any remaining setup where clang doesn't support an architecture but it can
expect an working gcc cross compiler to be available.
A nice side effect is that tests no longer need to differentiate architectures
that are included in production builds of clang and those that are not.
llvm-svn: 165545
This parameter is useless because nowhere used explicitly and always
gets its default value - "false".
The patch reviewed by Rafael Espindola.
llvm-svn: 165149
'clang-cpp'.
For now, the test uses "REQUIRES: shell" to determine if the host system
supports "ln -s", which it uses to create a 'clang-cpp' symlink. This is a bit
hacky and should likely be directly supported by lit.cfg.
llvm-svn: 161317
- lib/Driver/Driver.cpp, tools/driver/driver.cpp: Exit status should not be propagated, although clang driver should catch exceptions.
- test/Driver/crash-report.c: Add REQUIRES:shell for now.
FIXME: setenv should work also on Lit.InternalShellRunner.
- test/Driver/crash-report.c: Remove XFAIL.
Thanks to Chad, To point out the issue.
llvm-svn: 160343
Now that we're only using -frewrite-includes rather than full preprocessing
when producing repro source files, we should also include command line macro
definitions in the repro script.
I don't have a test case for this because I'm not sure if/how I can open the
crash report file when the name is only known by scraping the crash report
output. Suggestions welcome if anyone thinks it'd be helpful.
llvm-svn: 159592
In future changes we should:
* use __builtin_trap rather than derefing 'random' volatile pointers.
* avoid dumping temporary files into /tmp when running tests, instead
preferring a location that is properly cleaned up by lit.
Review by Chandler Carruth.
llvm-svn: 159469
Benjamin Kramer