Summary:
Clang companion patch to LLVM patch D31027, which adds support
for emitting minimized bitcode file for use in the thin link step.
Add a cc1 option -fthin-link-bitcode=<file> to trigger this behavior.
Depends on D31027.
Reviewers: mehdi_amini, pcc
Subscribers: cfe-commits, Prazek
Differential Revision: https://reviews.llvm.org/D31050
llvm-svn: 298639
Summary:
Because SamplePGO passes will be invoked twice in ThinLTO build: once at compile phase, the other at backend. We want to make sure the IR at the 2nd phase matches the hot part in pro
file, thus we do not want to inline hot callsites in the first phase.
Reviewers: tejohnson, eraman
Reviewed By: tejohnson
Subscribers: mehdi_amini, cfe-commits, Prazek
Differential Revision: https://reviews.llvm.org/D31202
llvm-svn: 298429
Summary: AddDiscriminator pass is only useful for sample pgo. This patch restricts AddDiscriminator to -fdebug-info-for-profiling so that it does not introduce unecessary debug size increases for non-sample-pgo builds.
Reviewers: dblaikie, aprantl
Reviewed By: dblaikie
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D30220
llvm-svn: 295764
Summary:
The LibFunc::Func enum holds enumerators named for libc functions.
Unfortunately, there are real situations, including libc implementations, where
function names are actually macros (musl uses "#define fopen64 fopen", for
example; any other transitively visible macro would have similar effects).
Strictly speaking, a conforming C++ Standard Library should provide any such
macros as functions instead (via <cstdio>). However, there are some "library"
functions which are not part of the standard, and thus not subject to this
rule (fopen64, for example). So, in order to be both portable and consistent,
the enum should not use the bare function names.
The old enum naming used a namespace LibFunc and an enum Func, with bare
enumerators. This patch changes LibFunc to be an enum with enumerators prefixed
with "LF_". (Unfortunately, a scoped enum is not sufficient to override macros.)
These changes are for clang. See https://reviews.llvm.org/D28476 for LLVM.
Reviewers: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D28477
llvm-svn: 292849
Summary:
This reverts commit r292662.
This change broke internal builds. Will provide a reproducer internally.
Subscribers: pcc, mehdi_amini, cfe-commits, mgorny
Differential Revision: https://reviews.llvm.org/D29025
llvm-svn: 292791
Summary:
SamplePGO uses profile with debug info to collect profile. Unlike the traditional debugging purpose, sample pgo needs more accurate debug info to represent the profile. We add -femit-accurate-debug-info for this purpose. It can be combined with all debugging modes (-g, -gmlt, etc). It makes sure that the following pieces of info is always emitted:
* start line of all subprograms
* linkage name of all subprograms
* standalone subprograms (functions that has neither inlined nor been inlined)
The impact on speccpu2006 binary size (size increase comparing with -g0 binary, also includes data for -g binary, which does not change with this patch):
-gmlt(orig) -gmlt(patched) -g
433.milc 4.68% 5.40% 19.73%
444.namd 8.45% 8.93% 45.99%
447.dealII 97.43% 115.21% 374.89%
450.soplex 27.75% 31.88% 126.04%
453.povray 21.81% 26.16% 92.03%
470.lbm 0.60% 0.67% 1.96%
482.sphinx3 5.77% 6.47% 26.17%
400.perlbench 17.81% 19.43% 73.08%
401.bzip2 3.73% 3.92% 12.18%
403.gcc 31.75% 34.48% 122.75%
429.mcf 0.78% 0.88% 3.89%
445.gobmk 6.08% 7.92% 42.27%
456.hmmer 10.36% 11.25% 35.23%
458.sjeng 5.08% 5.42% 14.36%
462.libquantum 1.71% 1.96% 6.36%
464.h264ref 15.61% 16.56% 43.92%
471.omnetpp 11.93% 15.84% 60.09%
473.astar 3.11% 3.69% 14.18%
483.xalancbmk 56.29% 81.63% 353.22%
geomean 15.60% 18.30% 57.81%
Debug info size change for -gmlt binary with this patch:
433.milc 13.46%
444.namd 5.35%
447.dealII 18.21%
450.soplex 14.68%
453.povray 19.65%
470.lbm 6.03%
482.sphinx3 11.21%
400.perlbench 8.91%
401.bzip2 4.41%
403.gcc 8.56%
429.mcf 8.24%
445.gobmk 29.47%
456.hmmer 8.19%
458.sjeng 6.05%
462.libquantum 11.23%
464.h264ref 5.93%
471.omnetpp 31.89%
473.astar 16.20%
483.xalancbmk 44.62%
geomean 16.83%
Reviewers: davidxl, andreadb, rob.lougher, dblaikie, echristo
Reviewed By: dblaikie, echristo
Subscribers: hfinkel, rob.lougher, andreadb, gbedwell, cfe-commits, probinson, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D25435
llvm-svn: 292458
Summary: LTO backend will not invoke SampleProfileLoader pass even if -fprofile-sample-use is specified. This patch passes the flag down so that pass manager can add the SampleProfileLoader pass correctly.
Reviewers: mehdi_amini, tejohnson
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D28588
llvm-svn: 291870
Summary: LTO backend will not invoke SampleProfileLoader pass even if -fprofile-sample-use is specified. This patch passes the flag down so that pass manager can add the SampleProfileLoader pass correctly.
Reviewers: mehdi_amini, tejohnson
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D28588
llvm-svn: 291774
Summary:
In order to simplify distributed build system integration, where actions
may be scheduled before the Thin Link which determines the list of
objects selected by the linker. The gold plugin currently will emit
0-sized index files for objects not selected by the link, to enable
checking for expected output files by the build system. If the build
system then schedules a backend action for these bitcode files, we want
to be able to fall back to normal compilation instead of failing.
Fallback is enabled under an option in LLVM (D28410), in which case a
nullptr is returned from llvm::getModuleSummaryIndexForFile. Clang can
just proceed with non-ThinLTO compilation in that case.
I am investigating whether this can be addressed in our build system,
but that is a longer term fix and so this enables a workaround in the
meantime.
Reviewers: mehdi_amini
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D28362
llvm-svn: 291303
inline assembly may use the `.include` directive to include other
content into the file. Without the integrated assembler, the `-I` group
gets passed to the assembler. Emulate this by collecting the header
search paths and passing them to the IAS.
Resolves PR24811!
llvm-svn: 291123
Summary:
We can simply import all external values with summaries included in
the individual index file created for the distributed backend job,
as only those are added to the individual index file created by the
WriteIndexesThinBackend (in addition to summaries for the original
module, which are skipped here).
While computing the cross module imports on this index would come to
the same conclusion as the original thin link import logic, it is
unnecessary work. And when tuning, it avoids the need to pass the
same function importing parameters (e.g. -import-instr-limit) to
both the thin link and the backends (otherwise they won't make the
same decisions).
Reviewers: mehdi_amini, pcc
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D28139
llvm-svn: 290674
This is kind of funny because I specifically did work to make this easy
and then it didn't actually get implemented.
I've also ported a set of tests that rely on this functionality to run
with the new PM as well as the old PM so that we don't mess this up in
the future.
llvm-svn: 290558
manager, and a code path to use it.
The option is actually a top-level option but does contain
'experimental' in the name. This is the compromise suggested by Richard
in discussions. We expect this option will be around long enough and
have enough users towards the end that it merits not being relegated to
CC1, but it still needs to be clear that this option will go away at
some point.
The backend code is a fresh codepath dedicated to handling the flow with
the new pass manager. This was also Richard's suggested code structuring
to essentially leave a clean path for development rather than carrying
complexity or idiosyncracies of how we do things just to share code with
the parts of this in common with the legacy pass manager. And it turns
out, not much is really in common even though we use the legacy pass
manager for codegen at this point.
I've switched a couple of tests to run with the new pass manager, and
they appear to work. There are still plenty of bugs that need squashing
(just with basic experiments I've found two already!) but they aren't in
this code, and the whole point is to expose the necessary hooks to start
experimenting with the pass manager in more realistic scenarios.
That said, I want to *strongly caution* anyone itching to play with
this: it is still *very shaky*. Several large components have not yet
been shaken down. For example I have bugs in both the always inliner and
inliner that I have already spotted and will be fixing independently.
Still, this is a fun milestone. =D
One thing not in this patch (but that might be very reasonable to add)
is some level of support for raw textual pass pipelines such as what
Sean had a patch for some time ago. I'm mostly interested in the more
traditional flow of getting the IR out of Clang and then running it
through opt, but I can see other use cases so someone may want to add
it.
And of course, *many* features are not yet supported!
- O1 is currently more like O2
- None of the sanitizers are wired up
- ObjC ARC optimizer isn't wired up
- ...
So plenty of stuff still lef to do!
Differential Revision: https://reviews.llvm.org/D28077
llvm-svn: 290450
-fno-inline-functions, -O0, and optnone.
These were really, really tangled together:
- We used the noinline LLVM attribute for -fno-inline
- But not for -fno-inline-functions (breaking LTO)
- But we did use it for -finline-hint-functions (yay, LTO is happy!)
- But we didn't for -O0 (LTO is sad yet again...)
- We had weird structuring of CodeGenOpts with both an inlining
enumeration and a boolean. They interacted in weird ways and
needlessly.
- A *lot* of set smashing went on with setting these, and then got worse
when we considered optnone and other inlining-effecting attributes.
- A bunch of inline affecting attributes were managed in a completely
different place from -fno-inline.
- Even with -fno-inline we failed to put the LLVM noinline attribute
onto many generated function definitions because they didn't show up
as AST-level functions.
- If you passed -O0 but -finline-functions we would run the normal
inliner pass in LLVM despite it being in the O0 pipeline, which really
doesn't make much sense.
- Lastly, we used things like '-fno-inline' to manipulate the pass
pipeline which forced the pass pipeline to be much more
parameterizable than it really needs to be. Instead we can *just* use
the optimization level to select a pipeline and control the rest via
attributes.
Sadly, this causes a bunch of churn in tests because we don't run the
optimizer in the tests and check the contents of attribute sets. It
would be awesome if attribute sets were a bit more FileCheck friendly,
but oh well.
I think this is a significant improvement and should remove the semantic
need to change what inliner pass we run in order to comply with the
requested inlining semantics by relying completely on attributes. It
also cleans up tho optnone and related handling a bit.
One unfortunate aspect of this is that for generating alwaysinline
routines like those in OpenMP we end up removing noinline and then
adding alwaysinline. I tried a bunch of other approaches, but because we
recompute function attributes from scratch and don't have a declaration
here I couldn't find anything substantially cleaner than this.
Differential Revision: https://reviews.llvm.org/D28053
llvm-svn: 290398
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
BackendUtil.cpp uses llvm::SmallSet but did not include the header. It was
included indirectly, but this will change once the AssumptionCache is removed.
NFC.
llvm-svn: 289752
Summary:
We used to create SampleProfileLoader pass in clang. This makes LTO/ThinLTO unable to add this pass in the linker plugin. This patch moves the SampleProfileLoader pass creation from
clang to llvm pass manager builder.
Reviewers: tejohnson, davidxl, dnovillo
Subscribers: mehdi_amini, cfe-commits
Differential Revision: https://reviews.llvm.org/D27744
llvm-svn: 289715
Summary:
We used to create SampleProfileLoader pass in clang. This makes LTO/ThinLTO unable to add this pass in the linker plugin. This patch moves the SampleProfileLoader pass creation from
clang to llvm pass manager builder.
Reviewers: tejohnson, davidxl, dnovillo
Subscribers: mehdi_amini, cfe-commits
Differential Revision: https://reviews.llvm.org/D27744
llvm-svn: 289670
Currently, TargetLibraryInfoWrapperPass is inserted by PMBuilder.
However, some passes are inserted manually before the PMBuilder
ones - if any of them happens to use TargetLibraryInfoWrapperPass,
it'll get a default-constructed one, with an unknown target triple.
This happens to InstrProfiling in D21736, breaking it.
Differential Revision: http://reviews.llvm.org/D21737
llvm-svn: 287688
The change in D26502 splits ReaderWriter.h, which contains the APIs
into both the BitReader and BitWriter libraries, into BitcodeReader.h
and BitcodeWriter.h.
Change clang uses to the appropriate split header(s).
llvm-svn: 286567
Summary: Use -fsanitize-recover instead of -mllvm -msan-keep-going: pass -fsanitize-recover value to msan.
Reviewers: eugenis
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D26354
Patch by Aleksey Shlyapnikov.
llvm-svn: 286148
The motivation for the change is that we can't have pseudo-global settings
for codegen living in TargetOptions because that doesn't work with LTO.
Ideally, these reciprocal attributes will be moved to the instruction-level
via FMF, metadata, or something else. But making them function attributes is
at least an improvement over the current state.
I'm committing this patch ahead of the related LLVM patch to avoid bot failures,
but if that patch needs to be reverted, then this should be reverted too.
Differential Revision: https://reviews.llvm.org/D24815
llvm-svn: 283251
Summary:
With this commit simple coroutines can be created in plain C using coroutine builtins.
Reviewers: rnk, EricWF, rsmith
Subscribers: modocache, mgorny, mehdi_amini, beanz, cfe-commits
Differential Revision: https://reviews.llvm.org/D24373
llvm-svn: 283155
Summary: We previously relies on InstructionCombining pass to remove invoke instructions. Now that we can inline invoke instructions correctly, we do not need these passes any more.
Reviewers: dnovillo
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D24730
llvm-svn: 281910
Summary:
This changes clang to use the llvm::lto::thinBackend function instead of
its own less comprehensive ThinLTO backend implementation.
Patch by Peter Collingbourne
Reviewers: tejohnson, mehdi_amini
Subscribers: cfe-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D21545
llvm-svn: 278541
This patch (with the corresponding ARM backend patch) adds support for
some new relocation models:
* Read-only position independence (ROPI): Code and read-only data is accessed
PC-relative. The offsets between all code and RO data sections are known at
static link time.
* Read-write position independence (RWPI): Read-write data is accessed relative
to a static base register. The offsets between all writeable data sections
are known at static link time.
These two modes are independent (they specify how different objects
should be addressed), so they can be used individually or together.
These modes are intended for bare-metal systems or systems with small
real-time operating systems. They are designed to avoid the need for a
dynamic linker, the only initialisation required is setting the static
base register to an appropriate value for RWPI code.
There is one C construct not currently supported by these modes: global
variables initialised to the address of another global variable or
function, where that address is not known at static-link time. There are
a few possible ways to solve this:
* Disallow this, and require the user to write their own initialisation
function if they need variables like this.
* Emit dynamic initialisers for these variables in the compiler, called from
the .init_array section (as is currently done for C++ dynamic initialisers).
We have a patch to do this, described in my original RFC email
(http://lists.llvm.org/pipermail/llvm-dev/2015-December/093022.html), but the
feedback from that RFC thread was that this is not something that belongs in
clang.
* Use a small dynamic loader to fix up these variables, by adding the
difference between the load and execution address of the relevant section.
This would require linker co-operation to generate a table of addresses that
need fixing up.
Differential Revision: https://reviews.llvm.org/D23196
llvm-svn: 278016
This changes the CompilerInstance::createOutputFile function to return
a std::unique_ptr<llvm::raw_ostream>, rather than an llvm::raw_ostream
implicitly owned by the CompilerInstance. This in most cases required that
I move ownership of the output stream to the relevant ASTConsumer.
The motivation for this change is to allow BackendConsumer to be a client
of interfaces such as D20268 which take ownership of the output stream.
Differential Revision: http://reviews.llvm.org/D21537
llvm-svn: 275507
Summary: InstCombine needs to be performed after simplifycfg and sroa, otherwise it may make bad optimization decisions.
Reviewers: davidxl, wmi, dnovillo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D21568
llvm-svn: 273606
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
Summary: We need to call PruneEH pass before AutoFDO pass so that some EH-related calls can get inlined in Sample Profile pass.
Reviewers: davidxl, dnovillo
Subscribers: junbuml, llvm-commits
Differential Revision: http://reviews.llvm.org/D21197
llvm-svn: 273298
Summary: Sample profile pass need to have instcombine pass. A related change is http://reviews.llvm.org/D17742. But we should not explicitly add dependency between to non-analysis passes. So we add the dependency here.
Reviewers: davidxl, dnovillo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D20502
llvm-svn: 271010
Summary:
Adds a new -fsanitize=efficiency-working-set flag to enable esan's working
set tool. Adds appropriate tests for the new flag.
Reviewers: aizatsky
Subscribers: vitalybuka, zhaoqin, kcc, eugenis, llvm-commits
Differential Revision: http://reviews.llvm.org/D20484
llvm-svn: 270641
Thread through -fsjlj-exceptions to the backend via the TargetOptions. This is
in preparation for supporting SjLj exceptions on x86 (e.g. for MinGW).
llvm-svn: 270528
Embedded bitcode should have private linkage instead of appending or external.
Otherwise, it will cause link failure due to duplicated symbols.
Also add llvm.embedded.module and llvm.cmdline to llvm.compiler.used so they
don't get optimized out.
rdar://problem/21555860
llvm-svn: 269679
Summary:
Teach clang to embed bitcode inside bitcode. When -fembed-bitcode cc1
option is used, clang will embed both the input bitcode and cc1
commandline into the bitcode in special sections before compiling to
the object file. Using -fembed-bitcode-marker will only introduce a
marker in both sections.
Depends on D17390
Reviewers: rsmith
Subscribers: yaron.keren, vsk, cfe-commits
Differential Revision: http://reviews.llvm.org/D17392
llvm-svn: 269202
Summary:
As of D18614, TargetMachine exposes a hook to add a set of passes that should
be run as early as possible. Invoke this hook from clang when setting up the
pass manager.
Reviewers: chandlerc
Subscribers: rnk, cfe-commits, tra
Differential Revision: http://reviews.llvm.org/D18617
llvm-svn: 267764
Summary:
Adds a framework to enable the instrumentation pass for the new
EfficiencySanitizer ("esan") family of tools. Adds a flag for esan's
cache fragmentation tool via -fsanitize=efficiency-cache-frag.
Adds appropriate tests for the new flag.
Reviewers: eugenis, vitalybuka, aizatsky, filcab
Subscribers: filcab, kubabrecka, llvm-commits, zhaoqin, kcc
Differential Revision: http://reviews.llvm.org/D19169
llvm-svn: 267059
Clang should pass -backend-option to LLVM even though there is no target machine, since LLVM passes are used when emitting LLVM IR.
Differential Revision: http://reviews.llvm.org/D17552
llvm-svn: 266117
It is possible to argue that the EABIVersion field is similar in spirit to the
ABI field in TargetOptions. It represents the embedded ABI that the target
follows. This will allow us to thread this information into the target
information construction.
llvm-svn: 265807
Revert the two changes to thread CodeGenOptions into the TargetInfo allocation
and to fix the layering violation by moving CodeGenOptions into Basic.
Code Generation is arguably not particularly "basic". This addresses Richard's
post-commit review comments. This change purely does the mechanical revert and
will be followed up with an alternate approach to thread the desired information
into TargetInfo.
llvm-svn: 265806
This is a mechanical move of CodeGenOptions from libFrontend to libBasic. This
fixes the layering violation introduced earlier by threading CodeGenOptions into
TargetInfo. It should also fix the modules based self-hosting builds. NFC.
llvm-svn: 265702
This is the companion to an LLVM patch that renamed the function index
data structures and files to use the more general module summary index.
(Recommit after fixing LLVM side to add back missed file)
llvm-svn: 263514
This is the companion to an LLVM patch that renamed the function index
data structures and files to use the more general module summary index.
llvm-svn: 263491
Use it to calculate UserLabelPrefix, instead of specifying it (often
incorrectly).
Note that the *actual* user label prefix has always come from the
DataLayout, and is handled within LLVM. The main thing clang's
TargetInfo::UserLabelPrefix did was to set the #define value. Having
these be different from each-other is just silly.
Differential Revision: http://reviews.llvm.org/D17183
llvm-svn: 262737
This patch changes cc1 option for PGO profile use from
-fprofile-instr-use=<path> to -fprofile-instrument-use-path=<path>.
-fprofile-instr-use=<path> is now a driver only option.
In addition to decouple the cc1 option from the driver level option, this patch
also enables IR level profile use. cc1 option handling now reads the profile
header and sets CodeGenOpt ProfileUse (valid values are {None, Clang, LLVM}
-- this is a common enum for -fprofile-instrument={}, for the profile
instrumentation), and invoke the pipeline to enable the respective PGO use pass.
Reviewers: silvas, davidxl
Differential Revision: http://reviews.llvm.org/D17737
llvm-svn: 262515
This patch expands cc1 option -fprofile-instrument= with a new value: -fprofile-instrument=llvm
which enables IR level PGO instrumentation.
Reviewers: davidxl, silvas
Differential Revision: http://reviews.llvm.org/D17622
llvm-svn: 262239
Summary: Use the new pipeline implemented in D17115
Reviewers: tejohnson
Subscribers: joker.eph, cfe-commits
Differential Revision: http://reviews.llvm.org/D17272
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 261045
This patch changes cc1 option -fprofile-instr-generate to an enum option
-fprofile-instrument={clang|none}. It also changes cc1 options
-fprofile-instr-generate= to -fprofile-instrument-path=.
The driver level option -fprofile-instr-generate and -fprofile-instr-generate=
remain intact. This change will pave the way to integrate new PGO
instrumentation in IR level.
Review: http://reviews.llvm.org/D16730
llvm-svn: 259811
Due to the new in-place renaming support added in r257174, we no
longer need to invoke ThinLTO global renaming from clang. It will be
invoked on the module in the FunctionImport pass (by an immediately
following llvm commit).
As a result, we don't need to load the FunctionInfoIndex as early,
so that is moved down into EmitAssemblyHelper::EmitAssembly.
llvm-svn: 257179
The /Brepro flag controls whether or not the compiler should embed
timestamps into the object file. Object files which do not embed
timestamps are not suitable for incremental linking but are suitable for
hermetic build systems and staged self-hosts of clang.
A normal clang spelling of this flag has been added,
-mincremental-linker-compatible.
llvm-svn: 256204
Reapplies r256063, except instead of frugally re-using an LLVM enum,
we define a Clang enum, to avoid exposing too much LLVM interface.
Differential Revision: http://reviews.llvm.org/D15650
llvm-svn: 256078
Summary:
Adds new option -fthinlto-index=<file> to invoke the LTO pipeline
along with function importing via clang using the supplied function
summary index file. This supports invoking the parallel ThinLTO
backend processes in a distributed build environment via clang.
Additionally, this causes the module linker to be invoked on the bitcode
file being compiled to perform any necessary promotion and renaming of
locals that are exported via the function summary index file.
Add a couple tests that confirm we get expected errors when we try to
use the new option on a file that isn't bitcode, or specify an invalid
index file. The tests also confirm that we trigger the expected function
import pass.
Depends on D15024
Reviewers: joker.eph, dexonsmith
Subscribers: joker.eph, davidxl, cfe-commits
Differential Revision: http://reviews.llvm.org/D15025
llvm-svn: 254927
