Document the intended use of the `.amdgcn.next_free_{s,v}gpr` in the
context of multiple kernels and functions.
Differential Revision: https://reviews.llvm.org/D59949
llvm-svn: 357289
Ensure Code Object V2 documentation is complete, but always contains a
warning and a link to the equivalent Code Object V3 documentation.
Explicitly indicate that any note records present in a code object that
are not documented must be considered deprecated and ignored.
Differential Revision: https://reviews.llvm.org/D59782
llvm-svn: 357176
Summary:
This is an alternative to D59539.
Let's suppose we have measured 4 different opcodes, and got: `0.5`, `1.0`, `1.5`, `2.0`.
Let's suppose we are using `-analysis-clustering-epsilon=0.5`.
By default now we will start processing the `0.5` point, find that `1.0` is it's neighbor, add them to a new cluster.
Then we will notice that `1.5` is a neighbor of `1.0` and add it to that same cluster.
Then we will notice that `2.0` is a neighbor of `1.5` and add it to that same cluster.
So all these points ended up in the same cluster.
This may or may not be a correct implementation of dbscan clustering algorithm.
But this is rather horribly broken for the reasons of comparing the clusters with the LLVM sched data.
Let's suppose all those opcodes are currently in the same sched cluster.
If i specify `-analysis-inconsistency-epsilon=0.5`, then no matter
the LLVM values this cluster will **never** match the LLVM values,
and thus this cluster will **always** be displayed as inconsistent.
The solution is obviously to split off some of these opcodes into different sched cluster.
But how do i do that? Out of 4 opcodes displayed in the inconsistency report,
which ones are the "bad ones"? Which ones are the most different from the checked-in data?
I'd need to go in to the `.yaml` and look it up manually.
The trivial solution is to, when creating clusters, don't use the full dbscan algorithm,
but instead "pick some unclustered point, pick all unclustered points that are it's neighbor,
put them all into a new cluster, repeat". And just so as it happens, we can arrive
at that algorithm by not performing the "add neighbors of a neighbor to the cluster" step.
But that won't work well once we teach analyze mode to operate in on-1D mode
(i.e. on more than a single measurement type at a time), because the clustering would
depend on the order of the measurements.
Instead, let's just create a single cluster per opcode, and put all the points of that opcode into said cluster.
And simultaneously check that every point in that cluster is a neighbor of every other point in the cluster,
and if they are not, the cluster (==opcode) is unstable.
This is //yet another// step to bring me closer to being able to continue cleanup of bdver2 sched model..
Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=40880 | PR40880 ]].
Reviewers: courbet, gchatelet
Reviewed By: courbet
Subscribers: tschuett, jdoerfert, RKSimon, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59820
llvm-svn: 357152
A section containing metadata on remark diagnostics will be emitted if
the flag (-mllvm) -remarks-section is present.
For now, the metadata is:
* a magic number for remarks: "REMARKS\0"
* the version number: a little-endian uint64_t
* the absolute file path to the serialized remark diagnostics: a
null-terminated string.
Differential Revision: https://reviews.llvm.org/D59571
llvm-svn: 357043
Just as as llvm IR supports explicitly specifying numeric value ids
for instructions, and emits them by default in textual output, now do
the same for blocks.
This is a slightly incompatible change in the textual IR format.
Previously, llvm would parse numeric labels as string names. E.g.
define void @f() {
br label %"55"
55:
ret void
}
defined a label *named* "55", even without needing to be quoted, while
the reference required quoting. Now, if you intend a block label which
looks like a value number to be a name, you must quote it in the
definition too (e.g. `"55":`).
Previously, llvm would print nameless blocks only as a comment, and
would omit it if there was no predecessor. This could cause confusion
for readers of the IR, just as unnamed instructions did prior to the
addition of "%5 = " syntax, back in 2008 (PR2480).
Now, it will always print a label for an unnamed block, with the
exception of the entry block. (IMO it may be better to print it for
the entry-block as well. However, that requires updating many more
tests.)
Thus, the following is supported, and is the canonical printing:
define i32 @f(i32, i32) {
%3 = add i32 %0, %1
br label %4
4:
ret i32 %3
}
New test cases covering this behavior are added, and other tests
updated as required.
Differential Revision: https://reviews.llvm.org/D58548
llvm-svn: 356789
Introduce a DW_OP_LLVM_convert Dwarf expression pseudo op that allows
for a convenient way to perform type conversions on the Dwarf expression
stack. As an additional bonus it paves the way for using other Dwarf
v5 ops that need to reference a base_type.
The new DW_OP_LLVM_convert is used from lib/Transforms/Utils/Local.cpp
to perform sext/zext on debug values but mainly the patch is about
preparing terrain for adding other Dwarf v5 ops that need to reference a
base_type.
For Dwarf v5 the op maps to DW_OP_convert and for earlier versions a
complex shift & mask pattern is generated to emulate sext/zext.
This is a recommit of r356442 with trivial fixes for the failing tests.
Differential Revision: https://reviews.llvm.org/D56587
llvm-svn: 356451
Introduce a DW_OP_LLVM_convert Dwarf expression pseudo op that allows
for a convenient way to perform type conversions on the Dwarf expression
stack. As an additional bonus it paves the way for using other Dwarf
v5 ops that need to reference a base_type.
The new DW_OP_LLVM_convert is used from lib/Transforms/Utils/Local.cpp
to perform sext/zext on debug values but mainly the patch is about
preparing terrain for adding other Dwarf v5 ops that need to reference a
base_type.
For Dwarf v5 the op maps to DW_OP_convert and for earlier versions a
complex shift & mask pattern is generated to emulate sext/zext.
Differential Revision: https://reviews.llvm.org/D56587
llvm-svn: 356442
Add an experimental buffer fat pointer address space that is currently
unhandled in the backend. This commit reserves address space 7 as a
non-integral pointer repsenting the 160-bit fat pointer (128-bit buffer
descriptor + 32-bit offset) that is heavily used in graphics workloads
using the AMDGPU backend.
Differential Revision: https://reviews.llvm.org/D58957
llvm-svn: 356373
Summary:
CoverageExporterJson::renderFiles accounts for most of the execution time given a large profdata file with multiple binaries.
Proposed solution is to generate JSON for each file in parallel and sort at the end to preserve deterministic output. Also added flags to skip generating parts of the output to trim the output size.
Patch by Sajjad Mirza (@sajjadm).
Reviewers: Dor1s, vsk
Reviewed By: Dor1s, vsk
Subscribers: liaoyuke, mgrang, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59277
llvm-svn: 356178
This patch adds a section, ``Object lifetime in optimized code'', that
documents how such intrinsics are supposed to be handled. It sets out some of
the principles of how they specify variable locations, and how long those
locations are valid for.
This patch also documents one of the objectives behind the variable-location
design, that we should never allow the debugger to observe a state of the
program that would not have appeared without optimization.
Differential Revision: https://reviews.llvm.org/D58726
llvm-svn: 356041
This indicates an intrinsic parameter is required to be a constant,
and should not be replaced with a non-constant value.
Add the attribute to all AMDGPU and generic intrinsics that comments
indicate it should apply to. I scanned other target intrinsics, but I
don't see any obvious comments indicating which arguments are intended
to be only immediates.
This breaks one questionable testcase for the autoupgrade. I'm unclear
on whether the autoupgrade is supposed to really handle declarations
which were never valid. The verifier fails because the attributes now
refer to a parameter past the end of the argument list.
llvm-svn: 355981
Add a note about legacy FunctionPassManager to the LLVM tutorial.
It seems to confuse some people, worth adding a warning to the tutorial
to elaborate and suggest using `llvm::legacy::FunctionPassManager` for
now. Not a perfect solution but hopefully will avoid confusion
in the meantime.
Differential Revision: https://reviews.llvm.org/D59258
llvm-svn: 355930
Use this feature to fix a bug on ARM where 4 byte alignment is
incorrectly assumed.
Differential Revision: https://reviews.llvm.org/D57335
llvm-svn: 355685
Summary:
Right now, when we encounter a string equality check,
e.g. `if (memcmp(a, b, s) == 0)`, we try to expand to a comparison if `s` is a
small compile-time constant, and fall back on calling `memcmp()` else.
This is sub-optimal because memcmp has to compute much more than
equality.
This patch replaces `memcmp(a, b, s) == 0` by `bcmp(a, b, s) == 0` on platforms
that support `bcmp`.
`bcmp` can be made much more efficient than `memcmp` because equality
compare is trivially parallel while lexicographic ordering has a chain
dependency.
Subscribers: fedor.sergeev, jyknight, ckennelly, gchatelet, llvm-commits
Differential Revision: https://reviews.llvm.org/D56593
llvm-svn: 355672
Use this feature to fix a bug on ARM where 4 byte alignment is
incorrectly assumed.
Differential Revision: https://reviews.llvm.org/D57335
llvm-svn: 355585
Use this feature to fix a bug on ARM where 4 byte alignment is
incorrectly assumed.
Differential Revision: https://reviews.llvm.org/D57335
llvm-svn: 355522
Summary:
The current install-clang-headers target installs clang's resource
directory headers. This is different from the install-llvm-headers
target, which installs LLVM's API headers. We want to introduce the
corresponding target to clang, and the natural name for that new target
would be install-clang-headers. Rename the existing target to
install-clang-resource-headers to free up the install-clang-headers name
for the new target, following the discussion on cfe-dev [1].
I didn't find any bots on zorg referencing install-clang-headers. I'll
send out another PSA to cfe-dev to accompany this rename.
[1] http://lists.llvm.org/pipermail/cfe-dev/2019-February/061365.html
Reviewers: beanz, phosek, tstellar, rnk, dim, serge-sans-paille
Subscribers: mgorny, javed.absar, jdoerfert, #sanitizers, openmp-commits, lldb-commits, cfe-commits, llvm-commits
Tags: #clang, #sanitizers, #lldb, #openmp, #llvm
Differential Revision: https://reviews.llvm.org/D58791
llvm-svn: 355340
This patch adds a new flag named -bottleneck-analysis to print out information
about throughput bottlenecks.
MCA knows how to identify and classify dynamic dispatch stalls. However, it
doesn't know how to analyze and highlight kernel bottlenecks. The goal of this
patch is to teach MCA how to correlate increases in backend pressure to backend
stalls (and therefore, the loss of throughput).
From a Scheduler point of view, backend pressure is a function of the scheduler
buffer usage (i.e. how the number of uOps in the scheduler buffers changes over
time). Backend pressure increases (or decreases) when there is a mismatch
between the number of opcodes dispatched, and the number of opcodes issued in
the same cycle. Since buffer resources are limited, continuous increases in
backend pressure would eventually leads to dispatch stalls. So, there is a
strong correlation between dispatch stalls, and how backpressure changed over
time.
This patch teaches how to identify situations where backend pressure increases
due to:
- unavailable pipeline resources.
- data dependencies.
Data dependencies may delay execution of instructions and therefore increase the
time that uOps have to spend in the scheduler buffers. That often translates to
an increase in backend pressure which may eventually lead to a bottleneck.
Contention on pipeline resources may also delay execution of instructions, and
lead to a temporary increase in backend pressure.
Internally, the Scheduler classifies instructions based on whether register /
memory operands are available or not.
An instruction is marked as "ready to execute" only if data dependencies are
fully resolved.
Every cycle, the Scheduler attempts to execute all instructions that are ready
to execute. If an instruction cannot execute because of unavailable pipeline
resources, then the Scheduler internally updates a BusyResourceUnits mask with
the ID of each unavailable resource.
ExecuteStage is responsible for tracking changes in backend pressure. If backend
pressure increases during a cycle because of contention on pipeline resources,
then ExecuteStage sends a "backend pressure" event to the listeners.
That event would contain information about instructions delayed by resource
pressure, as well as the BusyResourceUnits mask.
Note that ExecuteStage also knows how to identify situations where backpressure
increased because of delays introduced by data dependencies.
The SummaryView observes "backend pressure" events and prints out a "bottleneck
report".
Example of bottleneck report:
```
Cycles with backend pressure increase [ 99.89% ]
Throughput Bottlenecks:
Resource Pressure [ 0.00% ]
Data Dependencies: [ 99.89% ]
- Register Dependencies [ 0.00% ]
- Memory Dependencies [ 99.89% ]
```
A bottleneck report is printed out only if increases in backend pressure
eventually caused backend stalls.
About the time complexity:
Time complexity is linear in the number of instructions in the
Scheduler::PendingSet.
The average slowdown tends to be in the range of ~5-6%.
For memory intensive kernels, the slowdown can be significant if flag
-noalias=false is specified. In the worst case scenario I have observed a
slowdown of ~30% when flag -noalias=false was specified.
We can definitely recover part of that slowdown if we optimize class LSUnit (by
doing extra bookkeeping to speedup queries). For now, this new analysis is
disabled by default, and it can be enabled via flag -bottleneck-analysis. Users
of MCA as a library can enable the generation of pressure events through the
constructor of ExecuteStage.
This patch partially addresses https://bugs.llvm.org/show_bug.cgi?id=37494
Differential Revision: https://reviews.llvm.org/D58728
llvm-svn: 355308
This is a small addition to arithmetic operations that improves
expressiveness of the language.
Differential Revision: https://reviews.llvm.org/D58775
llvm-svn: 355187
This patch allows all forms of values for options to be used at the end
of a group. With the fix, it is possible to follow the way GNU binutils
tools handle grouping options better. For example, the -j option can be
used with objdump in any of the following ways:
$ objdump -d -j .text a.o
$ objdump -d -j.text a.o
$ objdump -dj .text a.o
$ objdump -dj.text a.o
Differential Revision: https://reviews.llvm.org/D58711
llvm-svn: 355185
If an option, which requires a value, has a `cl::Grouping` formatting
modifier, it works well as far as it is used at the end of a group,
or as a separate argument. However, if the option appears accidentally
in the middle of a group, the program just crashes. This patch prints
an error message instead.
Differential Revision: https://reviews.llvm.org/D58499
llvm-svn: 355184
Part 2 of CSPGO changes (mostly related to ProfileSummary).
Note that I use a default parameter in setProfileSummary() and getSummary().
This is to break the dependency in clang. I will make the parameter explicit
after changing clang in a separated patch.
Differential Revision: https://reviews.llvm.org/D54175
llvm-svn: 355131
Fix https://bugs.llvm.org/show_bug.cgi?id=38583: Describe
how memcpy/memmove/memset behave when len=0. Also fix
some fallout from when the alignment parameter was
replaced by an attribute.
This closes PR38583.
Patch by RalfJung (Ralf)
Differential Revision: https://reviews.llvm.org/D57600
llvm-svn: 354911
We have all the necessary legalization, expansion and unrolling support required for the *.overflow intrinsics with vector types, so update the docs to make that clear.
Note: vectorization is not in place yet (the non-homogenous return types aren't well supported) so we still must explicitly use the vectors intrinsics and not reply on slp/loop.
Differential Revision: https://reviews.llvm.org/D58618
llvm-svn: 354821
The patch adds support for --hash-filenames to llvm-cov. This option adds md5
hash of the source path to the name of the generated .gcov file. The option is
crucial for cases where you have multiple files with the same name but can't
use --preserve-paths as resulting filenames exceed the limit.
from gcov(1):
```
-x
--hash-filenames
By default, gcov uses the full pathname of the source files to to
create an output filename. This can lead to long filenames that
can overflow filesystem limits. This option creates names of the
form source-file##md5.gcov, where the source-file component is
the final filename part and the md5 component is calculated from
the full mangled name that would have been used otherwise.
```
Patch by Igor Ignatev!
Differential Revision: https://reviews.llvm.org/D58370
llvm-svn: 354379
Use some of the wording and the motivating example from r344555. The
lack of documentation was pointed out by Roman Lebedev.
Differential Revision: https://reviews.llvm.org/D58286
llvm-svn: 354167
If you want to build clang-tools-extra with monorepo, just add it to
LLVM_ENABLE_PROJECTS like with other projects.
See also "Separating clang-tools-extra from clang in LLVM_ENABLE_PROJECTS"
on cfe-dev.
Differential Revision: https://reviews.llvm.org/D58157
llvm-svn: 354057
Add some common recipes for downstream users developing on top of the
existing git mirrors. These instructions show how to migrate local
branches to the monorepo.
Differential Revision: https://reviews.llvm.org/D56550
llvm-svn: 353713
This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html
This patch adds a new CallBr IR instruction to support asm-goto
inline assembly like gcc as used by the linux kernel. This
instruction is both a call instruction and a terminator
instruction with multiple successors. Only inline assembly
usage is supported today.
This also adds a new INLINEASM_BR opcode to SelectionDAG and
MachineIR to represent an INLINEASM block that is also
considered a terminator instruction.
There will likely be more bug fixes and optimizations to follow
this, but we felt it had reached a point where we would like to
switch to an incremental development model.
Patch by Craig Topper, Alexander Ivchenko, Mikhail Dvoretckii
Differential Revision: https://reviews.llvm.org/D53765
llvm-svn: 353563
Summary:
Document that libFuzzer supports Windows, how to get it,
and its limitations.
Reviewers: kcc, morehouse, rnk, metzman
Reviewed By: kcc, rnk, metzman
Subscribers: hans, rnk
Differential Revision: https://reviews.llvm.org/D57597
llvm-svn: 353551
Summary:
The RFC on moving past C++11 got good traction:
http://lists.llvm.org/pipermail/llvm-dev/2019-January/129452.html
This patch therefore bumps the toolchain versions according to our policy:
llvm.org/docs/DeveloperPolicy.html#toolchain
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits, mehdi_amini, jyknight, rsmith, chandlerc, smeenai, hans, reames, lattner, lhames, erichkeane
Differential Revision: https://reviews.llvm.org/D57264
llvm-svn: 353374
A fallible iterator is one whose increment or decrement operations may fail.
This would usually be supported by replacing the ++ and -- operators with
methods that return error:
class MyFallibleIterator {
public:
// ...
Error inc();
Errro dec();
// ...
};
The downside of this style is that it no longer conforms to the C++ iterator
concept, and can not make use of standard algorithms and features such as
range-based for loops.
The fallible_iterator wrapper takes an iterator written in the style above
and adapts it to (mostly) conform with the C++ iterator concept. It does this
by providing standard ++ and -- operator implementations, returning any errors
generated via a side channel (an Error reference passed into the wrapper at
construction time), and immediately jumping the iterator to a known 'end'
value upon error. It also marks the Error as checked any time an iterator is
compared with a known end value and found to be inequal, allowing early exit
from loops without redundant error checking*.
Usage looks like:
MyFallibleIterator I = ..., E = ...;
Error Err = Error::success();
for (auto &Elem : make_fallible_range(I, E, Err)) {
// Loop body is only entered when safe.
// Early exits from loop body permitted without checking Err.
if (SomeCondition)
return;
}
if (Err)
// Handle error.
* Since failure causes a fallible iterator to jump to end, testing that a
fallible iterator is not an end value implicitly verifies that the error is a
success value, and so is equivalent to an error check.
Reviewers: dblaikie, rupprecht
Subscribers: mgorny, dexonsmith, kristina, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57618
llvm-svn: 353237
Add an intrinsic that takes 2 unsigned integers with the scale of them
provided as the third argument and performs fixed point multiplication on
them.
This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.
Differential Revision: https://reviews.llvm.org/D55625
llvm-svn: 353059
Summary:
Up until the point i have looked in the source, i didn't even understood that
i can disable 'cluster' output. I have always silenced it via ` &> /dev/null`.
(And hoped it wasn't contributing much of the run time.)
While i expect that it has it's use-cases i never once needed it so far.
If i forget to silence it, console is completely flooded with that output.
How about not expecting users to opt-out of analyses,
but to explicitly specify the analyses that should be performed?
Reviewers: courbet, gchatelet
Reviewed By: courbet
Subscribers: tschuett, RKSimon, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57648
llvm-svn: 353021
Reverting D57264 again, it looks like we're down to two bots that need fixing:
polly-amd64-linux
polly-arm-linux
They both have old versions of libstdc++ and recent clang.
llvm-svn: 352954
Summary:
The RFC on moving past C++11 got good traction:
http://lists.llvm.org/pipermail/llvm-dev/2019-January/129452.html
This patch therefore bumps the toolchain versions according to our policy:
llvm.org/docs/DeveloperPolicy.html#toolchain
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits, mehdi_amini, jyknight, rsmith, chandlerc, smeenai, hans, reames, lattner, lhames, erichkeane
Differential Revision: https://reviews.llvm.org/D57264
llvm-svn: 352951
A while back, createStringError was added to provide easier construction
of StringError instances, especially with formatting options. Prior to
this patch, that the documentation only mentions the standard method of
using it. Since createStringError is slightly shorter to type, and also
provides the formatting options, this patch updates the Programmer's
Manual to use the new function in its examples, and to mention the
printf formatting options. It also fixes a small typo in one of the
examples and removes the unnecessary make_error_code call.
llvm-svn: 352846
Summary:
The RFC on moving past C++11 got good traction:
http://lists.llvm.org/pipermail/llvm-dev/2019-January/129452.html
This patch therefore bumps the toolchain versions according to our policy:
llvm.org/docs/DeveloperPolicy.html#toolchain
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits, mehdi_amini, jyknight, rsmith, chandlerc, smeenai, hans, reames, lattner, lhames, erichkeane
Differential Revision: https://reviews.llvm.org/D57264
llvm-svn: 352834
Recommit r352791 after tweaking DerivedTypes.h slightly, so that gcc
doesn't choke on it, hopefully.
Original Message:
The FunctionCallee type is effectively a {FunctionType*,Value*} pair,
and is a useful convenience to enable code to continue passing the
result of getOrInsertFunction() through to EmitCall, even once pointer
types lose their pointee-type.
Then:
- update the CallInst/InvokeInst instruction creation functions to
take a Callee,
- modify getOrInsertFunction to return FunctionCallee, and
- update all callers appropriately.
One area of particular note is the change to the sanitizer
code. Previously, they had been casting the result of
`getOrInsertFunction` to a `Function*` via
`checkSanitizerInterfaceFunction`, and storing that. That would report
an error if someone had already inserted a function declaraction with
a mismatching signature.
However, in general, LLVM allows for such mismatches, as
`getOrInsertFunction` will automatically insert a bitcast if
needed. As part of this cleanup, cause the sanitizer code to do the
same. (It will call its functions using the expected signature,
however they may have been declared.)
Finally, in a small number of locations, callers of
`getOrInsertFunction` actually were expecting/requiring that a brand
new function was being created. In such cases, I've switched them to
Function::Create instead.
Differential Revision: https://reviews.llvm.org/D57315
llvm-svn: 352827
A handful of bots are still breaking, either because I missed them in my audit,
they were offline, or something else. I'm contacting their authors, but I'll
revert for now and re-commit later.
llvm-svn: 352814
Summary:
The RFC on moving past C++11 got good traction:
http://lists.llvm.org/pipermail/llvm-dev/2019-January/129452.html
This patch therefore bumps the toolchain versions according to our policy:
llvm.org/docs/DeveloperPolicy.html#toolchain
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits, mehdi_amini, jyknight, rsmith, chandlerc, smeenai, hans, reames, lattner, lhames, erichkeane
Differential Revision: https://reviews.llvm.org/D57264
llvm-svn: 352811
This reverts commit f47d6b38c7a61d50db4566b02719de05492dcef1 (r352791).
Seems to run into compilation failures with GCC (but not clang, where
I tested it). Reverting while I investigate.
llvm-svn: 352800
The FunctionCallee type is effectively a {FunctionType*,Value*} pair,
and is a useful convenience to enable code to continue passing the
result of getOrInsertFunction() through to EmitCall, even once pointer
types lose their pointee-type.
Then:
- update the CallInst/InvokeInst instruction creation functions to
take a Callee,
- modify getOrInsertFunction to return FunctionCallee, and
- update all callers appropriately.
One area of particular note is the change to the sanitizer
code. Previously, they had been casting the result of
`getOrInsertFunction` to a `Function*` via
`checkSanitizerInterfaceFunction`, and storing that. That would report
an error if someone had already inserted a function declaraction with
a mismatching signature.
However, in general, LLVM allows for such mismatches, as
`getOrInsertFunction` will automatically insert a bitcast if
needed. As part of this cleanup, cause the sanitizer code to do the
same. (It will call its functions using the expected signature,
however they may have been declared.)
Finally, in a small number of locations, callers of
`getOrInsertFunction` actually were expecting/requiring that a brand
new function was being created. In such cases, I've switched them to
Function::Create instead.
Differential Revision: https://reviews.llvm.org/D57315
llvm-svn: 352791
This is meant to be used with clang's __builtin_dynamic_object_size.
When 'true' is passed to this parameter, the intrinsic has the
potential to be folded into instructions that will be evaluated
at run time. When 'false', the objectsize intrinsic behaviour is
unchanged.
rdar://32212419
Differential revision: https://reviews.llvm.org/D56761
llvm-svn: 352664
If we just compile with -O0, clang will add optnone attributes
everywhere, so opt won't actually be able to perform any passes.
Instruct clang to not emit the optnone so opt can do its thing.
Differential Revision: https://reviews.llvm.org/D56950
llvm-svn: 352550
This fixes most references to the paths:
llvm.org/svn/
llvm.org/git/
llvm.org/viewvc/
github.com/llvm-mirror/
github.com/llvm-project/
reviews.llvm.org/diffusion/
to instead point to https://github.com/llvm/llvm-project.
This is *not* a trivial substitution, because additionally, all the
checkout instructions had to be migrated to instruct users on how to
use the monorepo layout, setting LLVM_ENABLE_PROJECTS instead of
checking out various projects into various subdirectories.
I've attempted to not change any scripts here, only documentation. The
scripts will have to be addressed separately.
Additionally, I've deleted one document which appeared to be outdated
and unneeded:
lldb/docs/building-with-debug-llvm.txt
Differential Revision: https://reviews.llvm.org/D57330
llvm-svn: 352514
If a stack trace or similar has a list of addresses from an executable
or DSO loaded at a variable address (e.g. due to ASLR), the addresses
will not directly correspond to the addresses stored in the object file.
If a user wishes to use llvm-symbolizer, they have to subtract the load
address from every address. This is somewhat inconvenient, especially as
the output of --print-address will result in the adjusted address being
listed, rather than the address coming from the stack trace, making it
harder to map results between the two.
This change adds a new switch to llvm-symbolizer --adjust-vma which
takes an offset, which is then used to automatically do this
calculation. The printed address remains the input address (allowing for
easy mapping), whilst the specified offset is applied to the addresses
when performing the lookup.
The switch is conceptually similar to llvm-objdump's new switch of the
same name (see D57051), which in turn mirrors a GNU switch. There is no
equivalent switch in addr2line.
Reviewed by: grimar
Differential Revision: https://reviews.llvm.org/D57151
llvm-svn: 352195
This patch extends TableGen language with !cond operator.
Instead of embedding !if inside !if which can get cumbersome,
one can now use !cond.
Below is an example to convert an integer 'x' into a string:
!cond(!lt(x,0) : "Negative",
!eq(x,0) : "Zero",
!eq(x,1) : "One,
1 : "MoreThanOne")
Reviewed By: hfinkel, simon_tatham, greened
Differential Revision: https://reviews.llvm.org/D55758
llvm-svn: 352185
Summary:
UBSan wants to detect when unreachable code is actually reached, so it
adds instrumentation before every `unreachable` instruction. However,
the optimizer will remove code after calls to functions marked with
`noreturn`. To avoid this UBSan removes `noreturn` from both the call
instruction as well as from the function itself. Unfortunately, ASan
relies on this annotation to unpoison the stack by inserting calls to
`_asan_handle_no_return` before `noreturn` functions. This is important
for functions that do not return but access the the stack memory, e.g.,
unwinder functions *like* `longjmp` (`longjmp` itself is actually
"double-proofed" via its interceptor). The result is that when ASan and
UBSan are combined, the `noreturn` attributes are missing and ASan
cannot unpoison the stack, so it has false positives when stack
unwinding is used.
Changes:
# UBSan now adds the `expect_noreturn` attribute whenever it removes
the `noreturn` attribute from a function
# ASan additionally checks for the presence of this attribute
Generated code:
```
call void @__asan_handle_no_return // Additionally inserted to avoid false positives
call void @longjmp
call void @__asan_handle_no_return
call void @__ubsan_handle_builtin_unreachable
unreachable
```
The second call to `__asan_handle_no_return` is redundant. This will be
cleaned up in a follow-up patch.
rdar://problem/40723397
Reviewers: delcypher, eugenis
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D56624
llvm-svn: 352003
This change adds two options, -i and -inlines as aliases for the -inlining option to llvm-symbolizer to improve compatibility with the GNU addr2line utility which accepts these options.
It also modifies existing tests that use -inlining to exercise these new aliases as well.
This fixes PR40073.
Reviewed by: jhenderson, Quolyk, ruiu
Differential Revision: https://reviews.llvm.org/D57083
llvm-svn: 351999
This fixes https://bugs.llvm.org/show_bug.cgi?id=40072.
GNU addr2line's --functions switch is off by default, has a short alias
of -f, and does not take an argument. This patch changes llvm-symbolizer
to allow the second and third point (changing the default behaviour may
have negative impacts on users). If the option is missing a value, it
now treats it as "linkage".
This change does cause one previously valid command-line to behave
differently. Before --functions <value> was accepted, but now only
--functions=<value> is allowed (as well as --functions). The old
behaviour will result in the value being treated as a positional
argument.
The previous testing for --functions=short has been pulled out into a
new test that also tests the other accepted values and option formats.
Reviewed by: ruiu
Differential Revision: https://reviews.llvm.org/D57049
llvm-svn: 351968
The old diagnostic form of the trace produced by -v and -vv looks
like:
```
check1:1:8: remark: CHECK: expected string found in input
CHECK: abc
^
<stdin>:1:3: note: found here
; abc def
^~~
```
When dumping annotated input is requested (via -dump-input), I find
that this old trace is not useful and is sometimes harmful:
1. The old trace is mostly redundant because the same basic
information also appears in the input dump's annotations.
2. The old trace buries any error diagnostic between it and the input
dump, but I find it useful to see any error diagnostic up front.
3. FILECHECK_OPTS=-dump-input=fail requests annotated input dumps only
for failed FileCheck calls. However, I have to also add -v or -vv
to get a full set of annotations, and that can produce massive
output from all FileCheck calls in all tests. That's a real
problem when I run this in the IDE I use, which grinds to a halt as
it tries to capture all that output.
When -dump-input=fail|always, this patch suppresses the old trace from
-v or -vv. Error diagnostics still print as usual. If you want the
old trace, perhaps to see variable expansions, you can set
-dump-input=none (the default).
Reviewed By: probinson
Differential Revision: https://reviews.llvm.org/D55825
llvm-svn: 351881
Summary:
A couple of changes in the Scudo documentation:
- tag the shell code blocks as `console`;
- document error messages that are displayed in some termination conditions,
the reason they triggered, and potential causes.
Reviewers: eugenis, enh
Reviewed By: eugenis
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D56857
llvm-svn: 351838
This broke the RISCV build, and even with that fixed, one of the RISCV
tests behaves surprisingly differently with asserts than without,
leaving there no clear test pattern to use. Generally it seems bad for
hte IR to differ substantially due to asserts (as in, an alloca is used
with asserts that isn't needed without!) and nothing I did simply would
fix it so I'm reverting back to green.
This also required reverting the RISCV build fix in r351782.
llvm-svn: 351796
Specifically, clarify the following:
1. Volatile load and store may access addresses that are not memory.
2. Volatile load and store do not modify arbitrary memory.
3. Volatile load and store do not trap.
Prompted by recent volatile discussion on llvmdev.
Currently, there's sort of a split in the source code about whether
volatile operations are allowed to trap; this resolves that dispute in
favor of not allowing them to trap.
Differential Revision: https://reviews.llvm.org/D53184
llvm-svn: 351772
Summary:
Capture the current agreed-upon toolchain update policy based on the following
discussions:
- LLVM dev meeting 2018 BoF "Migrating to C++14, and beyond!"
llvm.org/devmtg/2018-10/talk-abstracts.html#bof3
- A Short Policy Proposal Regarding Host Compilers
lists.llvm.org/pipermail/llvm-dev/2018-May/123238.html
- Using C++14 code in LLVM (2018)
lists.llvm.org/pipermail/llvm-dev/2018-May/123182.html
- Using C++14 code in LLVM (2017)
lists.llvm.org/pipermail/llvm-dev/2017-October/118673.html
- Using C++14 code in LLVM (2016)
lists.llvm.org/pipermail/llvm-dev/2016-October/105483.html
- Document and Enforce new Host Compiler Policy
llvm.org/D47073
- Require GCC 5.1 and LLVM 3.5 at a minimum
llvm.org/D46723
Subscribers: jkorous, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D56819
llvm-svn: 351765
all missed!
Thanks to Alex Bradbury for pointing this out, and the fact that I never
added the intended `legacy` anchor to the developer policy. Add that
anchor too. With hope, this will cause the links to all resolve
successfully.
llvm-svn: 351731
As noted in https://bugs.llvm.org/show_bug.cgi?id=36651, the specialization for
isPodLike<std::pair<...>> did not match the expectation of
std::is_trivially_copyable which makes the memcpy optimization invalid.
This patch renames the llvm::isPodLike trait into llvm::is_trivially_copyable.
Unfortunately std::is_trivially_copyable is not portable across compiler / STL
versions. So a portable version is provided too.
Note that the following specialization were invalid:
std::pair<T0, T1>
llvm::Optional<T>
Tests have been added to assert that former specialization are respected by the
standard usage of llvm::is_trivially_copyable, and that when a decent version
of std::is_trivially_copyable is available, llvm::is_trivially_copyable is
compared to std::is_trivially_copyable.
As of this patch, llvm::Optional is no longer considered trivially copyable,
even if T is. This is to be fixed in a later patch, as it has impact on a
long-running bug (see r347004)
Note that GCC warns about this UB, but this got silented by https://reviews.llvm.org/D50296.
Differential Revision: https://reviews.llvm.org/D54472
llvm-svn: 351701
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
This installs the new developer policy and moves all of the license
files across all LLVM projects in the monorepo to the new license
structure. The remaining projects will be moved independently.
Note that I've left odd formatting and other idiosyncracies of the
legacy license structure text alone to make the diff easier to read.
Critically, note that we do not in any case *remove* the old license
notice or terms, as that remains necessary until we finish the
relicensing process.
I've updated a few license files that refer to the LLVM license to
instead simply refer generically to whatever license the LLVM project is
under, basically trying to minimize confusion.
This is really the culmination of so many people. Chris led the
community discussions, drafted the policy update and organized the
multi-year string of meeting between lawyers across the community to
figure out the strategy. Numerous lawyers at companies in the community
spent their time figuring out initial answers, and then the Foundation's
lawyer Heather Meeker has done *so* much to help refine and get us ready
here. I could keep going on, but I just want to make sure everyone
realizes what a huge community effort this has been from the begining.
Differential Revision: https://reviews.llvm.org/D56897
llvm-svn: 351631
An abstract call site is a wrapper that allows to treat direct,
indirect, and callback calls the same. If an abstract call site
represents a direct or indirect call site it behaves like a stripped
down version of a normal call site object. The abstract call site can
also represent a callback call, thus the fact that the initially
called function (=broker) may invoke a third one (=callback callee).
In this case, the abstract call side hides the middle man, hence the
broker function. The result is a representation of the callback call,
inside the broker, but in the context of the original instruction that
invoked the broker.
Again, there are up to three functions involved when we talk about
callback call sites. The caller (1), which invokes the broker
function. The broker function (2), that may or may not invoke the
callback callee. And finally the callback callee (3), which is the
target of the callback call.
The abstract call site will handle the mapping from parameters to
arguments depending on the semantic of the broker function. However,
it is important to note that the mapping is often partial. Thus, some
arguments of the call/invoke instruction are mapped to parameters of
the callee while others are not. At the same time, arguments of the
callback callee might be unknown, thus "null" if queried.
This patch introduces also !callback metadata which describe how a
callback broker maps from parameters to arguments. This metadata is
directly created by clang for known broker functions, provided through
source code attributes by the user, or later deduced by analyses.
For motivation and additional information please see the corresponding
talk (slides/video)
https://llvm.org/devmtg/2018-10/talk-abstracts.html#talk20
as well as the LCPC paper
http://compilers.cs.uni-saarland.de/people/doerfert/par_opt_lcpc18.pdf
Differential Revision: https://reviews.llvm.org/D54498
llvm-svn: 351627
This change adds demangling support to the ELF side of llvm-readobj,
under the switch --demangle/-C.
The following places are demangled: symbol table dumps (static and
dynamic), relocation dumps (static and dynamic), addrsig dumps, call
graph profile dumps, and group section signature symbols.
Although GNU readelf doesn't support demangling, it is still a useful
feature to have, and brings it on a par with llvm-objdump's
capabilities.
This fixes https://bugs.llvm.org/show_bug.cgi?id=40054.
Reviewed by: grimar, rupprecht
Differential Revision: https://reviews.llvm.org/D56791
llvm-svn: 351450
Summary: This change factors out compiler checking / warning, and documents LLVM_FORCE_USE_OLD_TOOLCHAIN. It doesn't introduce any functional changes nor policy changes, these will come late.
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D56799
llvm-svn: 351387
Summary:
When running llvm-objdump with the -macho option objdump will by default
disassemble only the __TEXT,__text section (or __TEXT_EXEC,__text when
disassembling MH_KEXT_BUNDLE files). The -disassemble-all option is
treated no diferently than -disassemble.
This change upates llvm-objdump's MachO parsing code to disassemble all
__text sections found in a file when -disassemble-all is specified. This
is useful for disassembling files with more than one __text section, or
when disassembling files whose __text section is not present in __TEXT.
I added a lit test case that verifies "llvm-objdump -m -d" and
"llvm-objdump -m -D" produce the expected results on a reference binary.
I also updated the CommandGuide documentation for llvm-objdump.rst and
verified it renders correctly as man and html.
rdar://42899338
Reviewers: ab, pete, lhames
Reviewed By: lhames
Subscribers: rupprecht, llvm-commits
Differential Revision: https://reviews.llvm.org/D56649
llvm-svn: 351238
Summary:
Explicitly note that multithreading support is not included in the stable
ABI.
Differential Revision: https://reviews.llvm.org/D56681
llvm-svn: 351213
compiler identification lines in test-cases.
(Doing so only because it's then easier to search for references which
are actually important and need fixing.)
llvm-svn: 351200
official Git repository.
Remove the directions for using git-svn, and demote the prominence of
the svn instructions.
Also, fix a few other issues while I'm in there:
* Mention LLVM_ENABLE_PROJECTS more.
* Getting started doesn't need to mention test-suite, but should
mention clang and the other projects.
* Remove mentions of "configure", since that's long gone.
I've also adjusted a few other mentions of svn to point to github, but
have not done so comprehensively.
Differential Revision: https://reviews.llvm.org/D56654
llvm-svn: 351130
Part of the effort to refactoring frame pointer code generation. We used
to use two function attributes "no-frame-pointer-elim" and
"no-frame-pointer-elim-non-leaf" to represent three kinds of frame
pointer usage: (all) frames use frame pointer, (non-leaf) frames use
frame pointer, (none) frame use frame pointer. This CL makes the idea
explicit by using only one enum function attribute "frame-pointer"
Option "-frame-pointer=" replaces "-disable-fp-elim" for tools such as
llc.
"no-frame-pointer-elim" and "no-frame-pointer-elim-non-leaf" are still
supported for easy migration to "frame-pointer".
tests are mostly updated with
// replace command line args ‘-disable-fp-elim=false’ with ‘-frame-pointer=none’
grep -iIrnl '\-disable-fp-elim=false' * | xargs sed -i '' -e "s/-disable-fp-elim=false/-frame-pointer=none/g"
// replace command line args ‘-disable-fp-elim’ with ‘-frame-pointer=all’
grep -iIrnl '\-disable-fp-elim' * | xargs sed -i '' -e "s/-disable-fp-elim/-frame-pointer=all/g"
Patch by Yuanfang Chen (tabloid.adroit)!
Differential Revision: https://reviews.llvm.org/D56351
llvm-svn: 351049
This shortcut mechanism for creating types was added 10 years ago, but
has seen almost no uptake since then, neither internally nor in
external projects.
The very small number of characters saved by using it does not seem
worth the mental overhead of an additional type-creation API, so,
delete it.
Differential Revision: https://reviews.llvm.org/D56573
llvm-svn: 351020
This patch improves llvm-profdata show command:
(1) add -value-cutoff=<N> option: Show only those functions whose max count
values are greater or equal to N.
(2) add -list-below-cutoff option: Only output names of functions whose max
count value are below the cutoff.
(3) formats value-profile counts and prints out percentage.
Differential Revision: https://reviews.llvm.org/D56342
llvm-svn: 350673
In LTO or Thin-lto mode (though linker plugin), the module
names are of temp file names which are different for
different compilations. Using SourceFileName avoids the issue.
This should not change any functionality for current PGO as
all the current callers of getPGOFuncName() is before LTO.
llvm-svn: 350579
Make sure all print statements are compatible with Python 2 and Python3 using
the `from __future__ import print_function` statement.
Differential Revision: https://reviews.llvm.org/D56249
llvm-svn: 350307
Summary:
This function is very similar to add_llvm_library(), so this patch merges it
into add_llvm_library() and replaces all calls to add_llvm_loadable_module(lib ...)
with add_llvm_library(lib MODULE ...)
Reviewers: philip.pfaffe, beanz, chandlerc
Reviewed By: philip.pfaffe
Subscribers: chapuni, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D51748
llvm-svn: 349839
The current llvm.mem.parallel_loop_access metadata has a problem in that
it uses LoopIDs. LoopID unfortunately is not loop identifier. It is
neither unique (there's even a regression test assigning the some LoopID
to multiple loops; can otherwise happen if passes such as LoopVersioning
make copies of entire loops) nor persistent (every time a property is
removed/added from a LoopID's MDNode, it will also receive a new LoopID;
this happens e.g. when calling Loop::setLoopAlreadyUnrolled()).
Since most loop transformation passes change the loop attributes (even
if it just to mark that a loop should not be processed again as
llvm.loop.isvectorized does, for the versioned and unversioned loop),
the parallel access information is lost for any subsequent pass.
This patch unlinks LoopIDs and parallel accesses.
llvm.mem.parallel_loop_access metadata on instruction is replaced by
llvm.access.group metadata. llvm.access.group points to a distinct
MDNode with no operands (avoiding the problem to ever need to add/remove
operands), called "access group". Alternatively, it can point to a list
of access groups. The LoopID then has an attribute
llvm.loop.parallel_accesses with all the access groups that are parallel
(no dependencies carries by this loop).
This intentionally avoid any kind of "ID". Loops that are clones/have
their attributes modifies retain the llvm.loop.parallel_accesses
attribute. Access instructions that a cloned point to the same access
group. It is not necessary for each access to have it's own "ID" MDNode,
but those memory access instructions with the same behavior can be
grouped together.
The behavior of llvm.mem.parallel_loop_access is not changed by this
patch, but should be considered deprecated.
Differential Revision: https://reviews.llvm.org/D52116
llvm-svn: 349725
Some recent experience on llvm-dev pointed out some errors in the document:
- Assumption of ninja
- Use of --march rather than -march
- Problems with host include files when a multiarch setup was used
- Insufficient target information passed to assembler
- Instructions on using the cmake cache file BaremetalARM.cmake were
incomplete
There was also insufficient guidance on what to do when various stages
failed due to misconfiguration or missing steps.
Summary of changes:
- Fixed problems above
- Added a troubleshooting section with common errors.
- Cleared up one "at time of writing" that is no longer a problem.
Differential Revision: https://reviews.llvm.org/D55709
llvm-svn: 349477
Extend FileCheck to dump its input annotated with FileCheck's
diagnostics: errors, good matches if -v, and additional information if
-vv. The goal is to make it easier to visualize FileCheck's matching
behavior when debugging.
Each patch in this series implements input annotations for a
particular category of FileCheck diagnostics. While the first few
patches alone are somewhat useful, the annotations become much more
useful as later patches implement annotations for -v and -vv
diagnostics, which show the matching behavior leading up to the error.
This first patch implements boilerplate plus input annotations for
error diagnostics reporting that no matches were found for a
directive. These annotations mark the search ranges of the failed
directives. Instead of using the usual `^~~`, which is used by later
patches for good matches, these annotations use `X~~` so that this
category of errors is visually distinct.
For example:
```
$ FileCheck -dump-input=help
The following description was requested by -dump-input=help to
explain the input annotations printed by -dump-input=always and
-dump-input=fail:
- L: labels line number L of the input file
- T:L labels the match result for a pattern of type T from line L of
the check file
- X~~ marks search range when no match is found
- colors error
If you are not seeing color above or in input dumps, try: -color
$ FileCheck -v -dump-input=always check1 < input1 |& sed -n '/^Input file/,$p'
Input file: <stdin>
Check file: check1
-dump-input=help describes the format of the following dump.
Full input was:
<<<<<<
1: ; abc def
2: ; ghI jkl
next:3 X~~~~~~~~ error: no match found
>>>>>>
$ cat check1
CHECK: abc
CHECK-SAME: def
CHECK-NEXT: ghi
CHECK-SAME: jkl
$ cat input1
; abc def
; ghI jkl
```
Some additional details related to the boilerplate:
* Enabling: The annotated input dump is enabled by `-dump-input`,
which can also be set via the `FILECHECK_OPTS` environment variable.
Accepted values are `help`, `always`, `fail`, or `never`. As shown
above, `help` describes the format of the dump. `always` is helpful
when you want to investigate a successful FileCheck run, perhaps for
an unexpected pass. `-dump-input-on-failure` and
`FILECHECK_DUMP_INPUT_ON_FAILURE` remain as a deprecated alias for
`-dump-input=fail`.
* Diagnostics: The usual diagnostics are not suppressed in this mode
and are printed first. For brevity in the example above, I've
omitted them using a sed command. Sometimes they're perfectly
sufficient, and then they make debugging quicker than if you were
forced to hunt through a dump of long input looking for the error.
If you think they'll get in the way sometimes, keep in mind that
it's pretty easy to grep for the start of the input dump, which is
`<<<`.
* Colored Annotations: The annotated input is colored if colors are
enabled (enabling colors can be forced using -color). For example,
errors are red. However, as in the above example, colors are not
vital to reading the annotations.
I don't know how to test color in the output, so any hints here would
be appreciated.
Reviewed By: george.karpenkov, zturner, probinson
Differential Revision: https://reviews.llvm.org/D52999
llvm-svn: 349418
When multiple loop transformation are defined in a loop's metadata, their order of execution is defined by the order of their respective passes in the pass pipeline. For instance, e.g.
#pragma clang loop unroll_and_jam(enable)
#pragma clang loop distribute(enable)
is the same as
#pragma clang loop distribute(enable)
#pragma clang loop unroll_and_jam(enable)
and will try to loop-distribute before Unroll-And-Jam because the LoopDistribute pass is scheduled after UnrollAndJam pass. UnrollAndJamPass only supports one inner loop, i.e. it will necessarily fail after loop distribution. It is not possible to specify another execution order. Also,t the order of passes in the pipeline is subject to change between versions of LLVM, optimization options and which pass manager is used.
This patch adds 'followup' attributes to various loop transformation passes. These attributes define which attributes the resulting loop of a transformation should have. For instance,
!0 = !{!0, !1, !2}
!1 = !{!"llvm.loop.unroll_and_jam.enable"}
!2 = !{!"llvm.loop.unroll_and_jam.followup_inner", !3}
!3 = !{!"llvm.loop.distribute.enable"}
defines a loop ID (!0) to be unrolled-and-jammed (!1) and then the attribute !3 to be added to the jammed inner loop, which contains the instruction to distribute the inner loop.
Currently, in both pass managers, pass execution is in a fixed order and UnrollAndJamPass will not execute again after LoopDistribute. We hope to fix this in the future by allowing pass managers to run passes until a fixpoint is reached, use Polly to perform these transformations, or add a loop transformation pass which takes the order issue into account.
For mandatory/forced transformations (e.g. by having been declared by #pragma omp simd), the user must be notified when a transformation could not be performed. It is not possible that the responsible pass emits such a warning because the transformation might be 'hidden' in a followup attribute when it is executed, or it is not present in the pipeline at all. For this reason, this patche introduces a WarnMissedTransformations pass, to warn about orphaned transformations.
Since this changes the user-visible diagnostic message when a transformation is applied, two test cases in the clang repository need to be updated.
To ensure that no other transformation is executed before the intended one, the attribute `llvm.loop.disable_nonforced` can be added which should disable transformation heuristics before the intended transformation is applied. E.g. it would be surprising if a loop is distributed before a #pragma unroll_and_jam is applied.
With more supported code transformations (loop fusion, interchange, stripmining, offloading, etc.), transformations can be used as building blocks for more complex transformations (e.g. stripmining+stripmining+interchange -> tiling).
Reviewed By: hfinkel, dmgreen
Differential Revision: https://reviews.llvm.org/D49281
Differential Revision: https://reviews.llvm.org/D55288
llvm-svn: 348944
Add an intrinsic that takes 2 signed integers with the scale of them provided
as the third argument and performs fixed point multiplication on them.
This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.
Differential Revision: https://reviews.llvm.org/D54719
llvm-svn: 348912
This patch introduces a new instinsic `@llvm.experimental.widenable_condition`
that allows explicit representation for guards. It is an alternative to using
`@llvm.experimental.guard` intrinsic that does not contain implicit control flow.
We keep finding places where `@llvm.experimental.guard` is not supported or
treated too conservatively, and there are 2 reasons to that:
- `@llvm.experimental.guard` has memory write side effect to model implicit control flow,
and this sometimes confuses passes and analyzes that work with memory;
- Not all passes and analysis are aware of the semantics of guards. These passes treat them
as regular throwing call and have no idea that the condition of guard may be used to prove
something. One well-known place which had caused us troubles in the past is explicit loop
iteration count calculation in SCEV. Another example is new loop unswitching which is not
aware of guards. Whenever a new pass appears, we potentially have this problem there.
Rather than go and fix all these places (and commit to keep track of them and add support
in future), it seems more reasonable to leverage the existing optimizer's logic as much as possible.
The only significant difference between guards and regular explicit branches is that guard's condition
can be widened. It means that a guard contains (explicitly or implicitly) a `deopt` block successor,
and it is always legal to go there no matter what the guard condition is. The other successor is
a guarded block, and it is only legal to go there if the condition is true.
This patch introduces a new explicit form of guards alternative to `@llvm.experimental.guard`
intrinsic. Now a widenable guard can be represented in the CFG explicitly like this:
%widenable_condition = call i1 @llvm.experimental.widenable.condition()
%new_condition = and i1 %cond, %widenable_condition
br i1 %new_condition, label %guarded, label %deopt
guarded:
; Guarded instructions
deopt:
call type @llvm.experimental.deoptimize(<args...>) [ "deopt"(<deopt_args...>) ]
The new intrinsic `@llvm.experimental.widenable.condition` has semantics of an
`undef`, but the intrinsic prevents the optimizer from folding it early. This form
should exploit all optimization boons provided to `br` instuction, and it still can be
widened by replacing the result of `@llvm.experimental.widenable.condition()`
with `and` with any arbitrary boolean value (as long as the branch that is taken when
it is `false` has a deopt and has no side-effects).
For more motivation, please check llvm-dev discussion "[llvm-dev] Giving up using
implicit control flow in guards".
This patch introduces this new intrinsic with respective LangRef changes and a pass
that converts old-style guards (expressed as intrinsics) into the new form.
The naming discussion is still ungoing. Merging this to unblock further items. We can
later change the name of this intrinsic.
Reviewed By: reames, fedor.sergeev, sanjoy
Differential Revision: https://reviews.llvm.org/D51207
llvm-svn: 348593
Currently if you use -{start,stop}-{before,after}, it picks
the first instance with the matching pass name. If you run
the same pass multiple times, there's no way to distinguish them.
Allow specifying a run index wih ,N to specify which you mean.
llvm-svn: 348285
D47882, D48130 and D48131 introduce a new lowering strategy for part-word
atomicrmw/cmpxchg and uses it to lower these operations for the RISC-V target.
Rather than having AtomicExpandPass produce the LL/SC loop in the IR level, it
instead calculates the necessary mask values and inserts a target-specific
intrinsic, which is lowered at a much later stage (after register allocation).
This ensures that architecture-specific restrictions for forward-progress in
LL/SC loops can be guaranteed.
This patch documents this new AtomicExpandPass functionality. See the previous
llvm-dev RFC for more info
<http://lists.llvm.org/pipermail/llvm-dev/2018-June/123993.html>.
Differential Revision: https://reviews.llvm.org/D52234
llvm-svn: 347971
Summary:
Resubmit this with no changes because I think the build was broken
by a different diff.
-----
The prior diff had to be reverted because there were two tests
that failed. I updated the two tests in this diff
clang/test/Misc/pragma-attribute-supported-attributes-list.test
clang/test/SemaCXX/attr-speculative-load-hardening.cpp
----- Summary from Previous Diff (Still Accurate) -----
LLVM IR already has an attribute for speculative_load_hardening. Before
this commit, when a user passed the -mspeculative-load-hardening flag to
Clang, every function would have this attribute added to it. This Clang
attribute will allow users to opt into SLH on a function by function basis.
This can be applied to functions and Objective C methods.
Reviewers: chandlerc, echristo, kristof.beyls, aaron.ballman
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D54915
llvm-svn: 347701
until I figure out why the build is failing or timing out
***************************
Summary:
The prior diff had to be reverted because there were two tests
that failed. I updated the two tests in this diff
clang/test/Misc/pragma-attribute-supported-attributes-list.test
clang/test/SemaCXX/attr-speculative-load-hardening.cpp
LLVM IR already has an attribute for speculative_load_hardening. Before
this commit, when a user passed the -mspeculative-load-hardening flag to
Clang, every function would have this attribute added to it. This Clang
attribute will allow users to opt into SLH on a function by function
basis.
This can be applied to functions and Objective C methods.
Reviewers: chandlerc, echristo, kristof.beyls, aaron.ballman
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D54915
This reverts commit a5b3c232d1e3613f23efbc3960f8e23ea70f2a79.
(r347617)
llvm-svn: 347628
Summary:
The prior diff had to be reverted because there were two tests
that failed. I updated the two tests in this diff
clang/test/Misc/pragma-attribute-supported-attributes-list.test
clang/test/SemaCXX/attr-speculative-load-hardening.cpp
----- Summary from Previous Diff (Still Accurate) -----
LLVM IR already has an attribute for speculative_load_hardening. Before
this commit, when a user passed the -mspeculative-load-hardening flag to
Clang, every function would have this attribute added to it. This Clang
attribute will allow users to opt into SLH on a function by function basis.
This can be applied to functions and Objective C methods.
Reviewers: chandlerc, echristo, kristof.beyls, aaron.ballman
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D54915
llvm-svn: 347617
Summary:
Basic documentation of the Stack Safety Analysis.
It will be improved during review and upstream of an implementation.
Reviewers: kcc, eugenis, vlad.tsyrklevich, glider
Reviewed By: vlad.tsyrklevich
Subscribers: arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D53336
llvm-svn: 347612
Summary:
LLVM IR already has an attribute for speculative_load_hardening. Before
this commit, when a user passed the -mspeculative-load-hardening flag to
Clang, every function would have this attribute added to it. This Clang
attribute will allow users to opt into SLH on a function by function basis.
This can be applied to functions and Objective C methods.
Reviewers: chandlerc, echristo
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D54555
llvm-svn: 347586
RetireControlUnitStatistics now reports extra information about the ROB and the
avg/maximum number of entries consumed over the entire simulation.
Example:
Retire Control Unit - number of cycles where we saw N instructions retired:
[# retired], [# cycles]
0, 109 (17.9%)
1, 102 (16.7%)
2, 399 (65.4%)
Total ROB Entries: 64
Max Used ROB Entries: 35 ( 54.7% )
Average Used ROB Entries per cy: 32 ( 50.0% )
Documentation in llvm/docs/CommandGuide/llvmn-mca.rst has been updated to
reflect this change.
llvm-svn: 347493
* Add amdhsa prefix to names to allow other tools to use the metadata
without collision.
* Make names consistent.
* Simplify structure.
* Change note record ID.
* Switch from YAML to MsgPack format.
* Document metadata assembler directive.
Patch By: t-tye (Tony Tye)
Differential Revision: https://reviews.llvm.org/D53445
llvm-svn: 346992
A call to @llvm.trap can be expected to be cold (i.e. unlikely to be
reached in a normal program execution).
Outlining paths which unconditionally trap is an important memory
saving. As the hot/cold splitting pass (imho) should not treat all
noreturn calls as cold, explicitly mark @llvm.trap cold so that it can
be outlined.
Split out of https://reviews.llvm.org/D54244.
Differential Revision: https://reviews.llvm.org/D54329
llvm-svn: 346885
In some cases it is desirable to match the same pattern repeatedly
many times. Currently the only way to do it is to copy the same
check pattern as many times as needed. And that gets pretty unwieldy
when its more than count is big.
Introducing CHECK-COUNT-<num> directive which acts like a plain CHECK
directive yet matches the same pattern exactly <num> times.
Extended FileCheckType to a struct to add Count there.
Changed some parsing routines to handle non-fixed length of directive
(all currently existing directives were fixed-length).
The code is generic enough to allow future support for COUNT in more
than just PlainCheck directives.
See motivating example for this feature in reviews.llvm.org/D54223.
Reviewed By: chandlerc, dblaikie
Differential Revision: https://reviews.llvm.org/D54336
llvm-svn: 346722
Summary:
lcov tracefiles are used by various coverage reporting tools and build
systems (e.g., Bazel). It is a simple text-based format to parse and
more convenient to use than the JSON export format, which needs
additional processing to map regions/segments back to line numbers.
It's a little unfortunate that "text" format is now overloaded to refer
specifically to JSON for export, but I wanted to avoid making any
breaking changes to the UI of the llvm-cov tool at this time.
Patch by Tony Allevato (@allevato).
Reviewers: Dor1s, vsk
Reviewed By: Dor1s, vsk
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D54266
llvm-svn: 346506
This adds the llvm-side support for post-inlining evaluation of the
__builtin_constant_p GCC intrinsic.
Also fixed SCCPSolver::visitCallSite to not blow up when seeing a call
to a function where canConstantFoldTo returns true, and one of the
arguments is a struct.
Updated from patch initially by Janusz Sobczak.
Differential Revision: https://reviews.llvm.org/D4276
llvm-svn: 346322
Document what is expected during:
* triaging
* actively working on a bug
* closing/resolving
Also document how we maintain:
* product/component breakdown
* default-cc lists per component
Differential Revision: https://reviews.llvm.org/D53691
llvm-svn: 346299
This feature makes it easy to tune FileCheck diagnostic output when
running the test suite via ninja, a bot, or an IDE. For example:
```
$ FILECHECK_OPTS='-color -v -dump-input-on-failure' \
LIT_FILTER='OpenMP/for_codegen.cpp' ninja check-clang \
| less -R
```
Reviewed By: probinson
Differential Revision: https://reviews.llvm.org/D53517
llvm-svn: 346272
Depending on who you ask, PGO grants a 15%-25% improvement in build
times when using clang. Sadly, hooking everything up properly to
generate a profile and apply it to clang isn't always straightforward.
This script (and the accompanying docs) aim to make this process easier;
ideally, a single invocation of the given script.
In terms of testing, I've got a cronjob on my Debian box that's meant to
run this a few times per week, and I tried manually running it on a puny
Gentoo box I have (four whole Atom cores!). Nothing obviously broke.
¯\_(ツ)_/¯
I don't know if we have a Python style guide, so I just shoved this
through yapf with all the defaults on.
Finally, though the focus is clang at the moment, the hope is that this
is easily applicable to other LLVM-y tools with minimal effort (e.g.
lld, opt, ...). Hence, this lives in llvm/utils and tries to be somewhat
ambiguous about naming.
Differential Revision: https://reviews.llvm.org/D53598
llvm-svn: 345427
Summary:
The pfm counters are now in the ExegesisTarget rather than the
MCSchedModel (PR39165).
This also compresses the pfm counter tables (PR37068).
Reviewers: RKSimon, gchatelet
Subscribers: mgrang, llvm-commits
Differential Revision: https://reviews.llvm.org/D52932
llvm-svn: 345243
(Relands r344930, reverted in r344935, and now hopefully fixed for
Windows.)
While this change specifically targets FileCheck, it affects any tool
using the same SourceMgr facilities.
Previously, -color was documented in FileCheck's -help output, but
-color had no effect. Now, -color obeys its documentation: it forces
colors to be used in FileCheck diagnostics even when stderr is not a
terminal.
-color is especially helpful when combined with FileCheck's -v, which
can produce a long series of diagnostics that you might wish to pipe
to a pager, such as less -R. The WithColor extensions here will also
help to clean up color usage in FileCheck's annotated dump of input,
which is proposed in D52999.
Reviewed By: JDevlieghere, zturner
Differential Revision: https://reviews.llvm.org/D53419
llvm-svn: 345202
Add a list of benchmarks, applications and algorithms which are under
discussion to be added to the test-suite.
The initial list includes the the benchmarks mentioned at
https://llvm.org/PR34216, missing SPEC benchmarks, some image processing
algorithms and a few others. The bug tracker only allows adding to the
discussion, not removing, commenting, adding details to individual
benchmarks.
The first proposal was to add these benchmark into the test-suite
repository, but after a discussion, adding it to llvm/docs/Proposals
seem more appropriate. One advantage is that llvm.org will have a
browsable web page with these suggestions.
Suggested-by: Hal Finkel
Differential Revision: https://reviews.llvm.org/D46714
llvm-svn: 345074
While this change specifically targets FileCheck, it affects any tool
using the same SourceMgr facilities.
Previously, -color was documented in FileCheck's -help output, but
-color had no effect. Now, -color obeys its documentation: it forces
colors to be used in FileCheck diagnostics even when stderr is not a
terminal.
-color is especially helpful when combined with FileCheck's -v, which
can produce a long series of diagnostics that you might wish to pipe
to a pager, such as less -R. The WithColor extensions here will also
help to clean up color usage in FileCheck's annotated dump of input,
which is proposed in D52999.
Reviewed By: JDevlieghere
Differential Revision: https://reviews.llvm.org/D53419
llvm-svn: 344930
Allows to disable direct TLS segment access (%fs or %gs). GCC supports
a similar flag, it can be useful in some circumstances, e.g. when a thread
context block needs to be updated directly from user space. More info
and specific use cases: https://bugs.llvm.org/show_bug.cgi?id=16145
There is another revision for clang as well.
Related: D53102
All X86 CodeGen tests appear to pass:
```
[46/47] Running lit suite /SourceCache/llvm-trunk-8.0/test/CodeGen
Testing Time: 23.17s
Expected Passes : 3801
Expected Failures : 15
Unsupported Tests : 8021
```
Reviewed by: Craig Topper.
Patch by nruslan (Ruslan Nikolaev).
Differential Revision: https://reviews.llvm.org/D53103
llvm-svn: 344723
Returning the error to clients provides an opportunity to introduce readers to
the Expected and Error APIs and makes the tutorial more useful as a starting
point for a real JIT class, while only slightly complicating the code.
llvm-svn: 344720
Summary:
We try to recover gracefully on instructions that would crash the
program.
This includes some refactoring of runMeasurement() implementations.
Reviewers: gchatelet
Subscribers: tschuett, llvm-commits
Differential Revision: https://reviews.llvm.org/D53371
llvm-svn: 344695
Summary:
These new intrinsics have the semantics of the `minimum` and `maximum`
operations specified by the latest draft of IEEE 754-2018. Unlike
llvm.minnum and llvm.maxnum, these new intrinsics propagate NaNs and
always treat -0.0 as less than 0.0. `minimum` and `maximum` lower
directly to the existing `fminnan` and `fmaxnan` ISel DAG nodes. It is
safe to reuse these DAG nodes because before this patch were only
emitted in situations where there were known to be no NaN arguments or
where NaN propagation was correct and there were known to be no zero
arguments. I know of only four backends that lower fminnan and
fmaxnan: WebAssembly, ARM, AArch64, and SystemZ, and each of these
lowers fminnan and fmaxnan to instructions that are compatible with
the IEEE 754-2018 semantics.
Reviewers: aheejin, dschuff, sunfish, javed.absar
Subscribers: kristof.beyls, dexonsmith, kristina, llvm-commits
Differential Revision: https://reviews.llvm.org/D52764
llvm-svn: 344437
Summary:
This is a step towards fixing PR38048.
Note that right now the measurements are given per instruction. We'll
need to give measurements a per code snippet and update the analysis (PR38731).
Reviewers: gchatelet
Subscribers: tschuett, llvm-commits
Differential Revision: https://reviews.llvm.org/D52041
llvm-svn: 342947
In my original diff I missed #include "llvm/System/Thing.h" and forgot to update a
reference to .inc files a few lines down. This patch corrects these things as
they were missed in revision 342500.
llvm-svn: 342705
Summary:
Some lines have a hit counter where they should not have one.
For example, in C++, some cleanup is adding at the end of a scope represented by a '}'.
So such a line has a hit counter where a user expects to not have one.
The goal of the patch is to add this information in DILocation which is used to get the covered lines in GCOVProfiling.cpp.
A following patch in clang will add this information when generating IR (https://reviews.llvm.org/D49916).
Reviewers: marco-c, davidxl, vsk, javed.absar, rnk
Reviewed By: rnk
Subscribers: eraman, xur, danielcdh, aprantl, rnk, dblaikie, #debug-info, vsk, llvm-commits, sylvestre.ledru
Tags: #debug-info
Differential Revision: https://reviews.llvm.org/D49915
llvm-svn: 342631
System Library has been a long deprecated term along with the path lib/System, having been superseded/renamed
to the Support Library a long time ago. These patches reflect those changes in documentation as well as
update some outdated examples and provide context to the origin of the Support Library.
Differential Revision: https://reviews.llvm.org/D52107
llvm-svn: 342500
Summary:
Remove note about summary being ignored. Update to reflect the
fact that summary is now parsed by llvm-as.
While here, fix one summary format that changed since the initial
implementation.
Reviewers: dexonsmith
Subscribers: inglorion, llvm-commits
Differential Revision: https://reviews.llvm.org/D51540
llvm-svn: 342479
add a tool to generate symbol remapping files.
Summary:
The new tool llvm-cxxmap builds a symbol mapping table from a file containing
a description of partial equivalences to apply to mangled names and files
containing old and new symbol tables.
Reviewers: davidxl
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D51470
llvm-svn: 342168
The assertion in MCCodeView.cpp was resolved in r340878.
This reverts both r340905 and r340836, making benchmarks build by
default everywhere.
llvm-svn: 341716
Load Hardening.
Wires up the existing pass to work with a proper IR attribute rather
than just a hidden/internal flag. The internal flag continues to work
for now, but I'll likely remove it soon.
Most of the churn here is adding the IR attribute. I talked about this
Kristof Beyls and he seemed at least initially OK with this direction.
The idea of using a full attribute here is that we *do* expect at least
some forms of this for other architectures. There isn't anything
*inherently* x86-specific about this technique, just that we only have
an implementation for x86 at the moment.
While we could potentially expose this as a Clang-level attribute as
well, that seems like a good question to defer for the moment as it
isn't 100% clear whether that or some other programmer interface (or
both?) would be best. We'll defer the programmer interface side of this
for now, but at least get to the point where the feature can be enabled
without relying on implementation details.
This also allows us to do something that was really hard before: we can
enable *just* the indirect call retpolines when using SLH. For x86, we
don't have any other way to mitigate indirect calls. Other architectures
may take a different approach of course, and none of this is surfaced to
user-level flags.
Differential Revision: https://reviews.llvm.org/D51157
llvm-svn: 341363
implementing the proposed mitigation technique described in the original
design document.
The idea is to check after calls that the return address used to arrive
at that location is in fact the correct address. In the event of
a mis-predicted return which reaches a *valid* return but not the
*correct* return, this will detect the mismatch much like it would
a mispredicted conditional branch.
This is the last published attack vector that I am aware of in the
Spectre v1 space which is not mitigated by SLH+retpolines. However,
don't read *too* much into that: this is an area of ongoing research
where we expect more issues to be discovered in the future, and it also
makes no attempt to mitigate Spectre v4. Still, this is an important
completeness bar for SLH.
The change here is of course delightfully simple. It was predicated on
cutting support for post-instruction symbols into LLVM which was not at
all simple. Many thanks to Hal Finkel, Reid Kleckner, and Justin Bogner
who helped me figure out how to do a bunch of the complex changes
involved there.
Differential Revision: https://reviews.llvm.org/D50837
llvm-svn: 341358
- Remove duplication: Both TestingGuide and TestSuiteMakefileGuide
would give a similar overview over the test-suite.
- Present cmake/lit as the default/normal way of running the test-suite:
- Move information about the cmake/lit testsuite into the new
TestSuiteGuide.rst file. Mark the remaining information in
TestSuiteMakefilesGuide.rst as deprecated.
- General simplification and shorting of language.
- Remove paragraphs about tests known to fail as everything should pass
nowadays.
- Remove paragraph about zlib requirement; it's not required anymore
since we copied a zlib source snapshot into the test-suite.
- Remove paragraph about comparison with "native compiler". Correctness is
always checked against reference outputs nowadays.
- Change cmake/lit quickstart section to recommend `pip` for installing
lit and use `CMAKE_C_COMPILER` and a cache file in the example as that
is what most people will end up doing anyway. Also a section about
compare.py to quickstart.
- Document `Bitcode` and `MicroBenchmarks` directories.
- Add section with commonly used cmake configuration options.
- Add section about showing and comparing result files via compare.py.
- Add section about using external benchmark suites.
- Add section about using custom benchmark suites.
- Add section about profile guided optimization.
- Add section about cross-compilation and running on external devices.
Differential Revision: https://reviews.llvm.org/D51465
llvm-svn: 341260
This patch introduces the following changes to the DispatchStatistics view:
* DispatchStatistics now reports the number of dispatched opcodes instead of
the number of dispatched instructions.
* The "Dynamic Dispatch Stall Cycles" table now also reports the percentage of
stall cycles against the total simulated cycles.
This change allows users to easily compare dispatch group sizes with the
processor DispatchWidth.
Before this change, it was difficult to correlate the two numbers, since
DispatchStatistics view reported numbers of instructions (instead of opcodes).
DispatchWidth defines the maximum size of a dispatch group in terms of number of
micro opcodes.
The other change introduced by this patch is related to how DispatchStage
generates "instruction dispatch" events.
In particular:
* There can be multiple dispatch events associated with a same instruction
* Each dispatch event now encapsulates the number of dispatched micro opcodes.
The number of micro opcodes declared by an instruction may exceed the processor
DispatchWidth. Therefore, we cannot assume that instructions are always fully
dispatched in a single cycle.
DispatchStage knows already how to handle instructions declaring a number of
opcodes bigger that DispatchWidth. However, DispatchStage always emitted a
single instruction dispatch event (during the first simulated dispatch cycle)
for instructions dispatched.
With this patch, DispatchStage now correctly notifies multiple dispatch events
for instructions that cannot be dispatched in a single cycle.
A few views had to be modified. Views can no longer assume that there can only
be one dispatch event per instruction.
Tests (and docs) have been updated.
Differential Revision: https://reviews.llvm.org/D51430
llvm-svn: 341055
This patch adds two new fields to the perf report generated by the SummaryView.
Fields are now logically organized into two small groups; only the second group
contains throughput indicators.
Example:
```
Iterations: 100
Instructions: 300
Total Cycles: 414
Total uOps: 700
Dispatch Width: 4
uOps Per Cycle: 1.69
IPC: 0.72
Block RThroughput: 4.0
```
This patch also updates the docs for llvm-mca.
Due to the nature of this change, several tests in the tools/llvm-mca directory
were affected, and had to be updated using script `update_mca_test_checks.py`.
llvm-svn: 340946
The problems with benchmark build should be fixed now, but Windows
buildbots still run into errors seemingly because of the bug in
clang-cl. Because of that, benchmark shouldn't be built on Windows at
this point.
llvm-svn: 340905
