Commit Graph

21445 Commits

Author SHA1 Message Date
Nick Kledzik
367cf70f27 [llvm-objdump] for mach-o add -bind, -lazy-bind, and -weak-bind options
This finishes the ability of llvm-objdump to print out all information from
the LC_DYLD_INFO load command.

The -bind option prints out symbolic references that dyld must resolve 
immediately.

The -lazy-bind option prints out symbolc reference that are lazily resolved on 
first use.

The -weak-bind option prints out information about symbols which dyld must
try to coalesce across images.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217853 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-16 01:41:51 +00:00
David Blaikie
ccaf6dd1d9 Fix indenting caused by clang-format+spuriously indented access specifier in r216925
Caught in post-commit review by Justin Bogner.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217837 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 22:20:31 +00:00
Juergen Ributzka
323445f706 [FastISel][AArch64] Add lowering support for frem.
This lowers frem to a runtime libcall inside fast-isel.

The test case also checks the CallLoweringInfo bug that was exposed by this
change.

This fixes rdar://problem/18342783.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217833 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 22:07:49 +00:00
Juergen Ributzka
7d8b5f7777 [FastISel] Fix a bug in FastISel::CallLoweringInfo.
This fixes a bug in FastISel::CallLoweringInfo, where the number of
arguments was obtained from the argument vector before it had been
initialized.

Test case follows in another commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217832 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 22:07:44 +00:00
Nick Kledzik
9885a59108 [Support] add decodeSLEB128()
We already have routines to encode SLEB128 as well as encode/decode ULEB128.
This last function fills out the matrix.  I'll need this for some llvm-objdump
work I am doing.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217830 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 21:51:49 +00:00
Juergen Ributzka
1ee1e8bdc2 [FastISel] Move optimizeCmpPredicate to FastISel base class. NFC.
Make the optimizeCmpPredicate function available to all targets.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217822 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 20:47:13 +00:00
David Majnemer
f1198da05c MC: Add support for BigObj
Teach WinCOFFObjectWriter how to write -mbig-obj style object files;
these object files allow for more sections inside an object file.

Our support for BigObj is notably different from binutils and cl: we
implicitly upgrade object files to BigObj instead of asking the user to
compile the same file *again* but with another flag.  This matches up
with how LLVM treats ELF variants.

This was tested by forcing LLVM to always emit BigObj files and running
the entire test suite.  A specific test has also been added.

I've lowered the maximum number of sections in a normal COFF file,
VS "14" CTP 3 supports no more than 65279 sections.  This is important
otherwise we might not switch to BigObj quickly enough, leaving us with
a COFF file that we couldn't link.

yaml2obj support is all that remains to implement.

Differential Revision: http://reviews.llvm.org/D5349

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217812 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 19:42:42 +00:00
David Blaikie
ec182fe2e5 Fix memory leak in error paths in YAMLTraits by using unique_ptr
There's some other cleanup that could happen here, but this is at least
the mechanical transformation to unique_ptr.

Derived from a patch by Anton Yartsev.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217803 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 18:39:24 +00:00
Rafael Espindola
3f0ce4fa18 Fix a lot of confusion around inserting nops on empty functions.
On MachO, and MachO only, we cannot have a truly empty function since that
breaks the linker logic for atomizing the section.

When we are emitting a frame pointer, the presence of an unreachable will
create a cfi instruction pointing past the last instruction. This is perfectly
fine. The FDE information encodes the pc range it applies to. If some tool
cannot handle this, we should explicitly say which bug we are working around
and only work around it when it is actually relevant (not for ELF for example).

Given the unreachable we could omit the .cfi_def_cfa_register, but then
again, we could also omit the entire function prologue if we wanted to.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217801 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 18:32:58 +00:00
Lang Hames
b01c85b421 [MCJIT] Start Stringref-izing the ExecutionEngine interface.
More methods to follow.

Using StringRef allows us the EE interface to work with more string types
without forcing construction of std::strings.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217794 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 17:50:22 +00:00
Benjamin Kramer
187089d412 Spell out the template args for compilers having issues with the injected class
name.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217780 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 16:13:33 +00:00
Benjamin Kramer
57a73c27b1 Use IntrusiveRefCntPtr to manage the lifetime of BitCodeAbbrevs.
This doesn't change the interface or gives additional safety but removes
a ton of retain/release boilerplate.

No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217778 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 15:44:14 +00:00
Frederic Riss
04dc1486ac Move replaceAllUsesWith() from DIType to DIDescriptor.
RAUW was only used on DIType to merge declarations and full definitions
of types. In order to support the same functionality for functions and
global variables, move the function up type DI type hierarchy to the
common parent of DIType, DISubprogram and DIVariable which is
DIDescriptor.

This functionality will be exercized when we add the code to emit
imported declarations for forward declared function/variables.

Reviewers: echristo, dblaikie, aprantl

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5325

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217748 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 07:50:36 +00:00
Justin Bogner
baca001683 llvm-cov: Simplify CounterMappingRegion, pushing logic to its user
A single function in SourceCoverageDataManager was the only user of
some of the comparisons in CounterMappingRegion, and at this point we
know that only one file is relevant. This lets us use slightly simpler
logic directly in the client.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217745 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 03:41:01 +00:00
Nick Lewycky
c2104d4856 Add control of function merging to the PMBuilder.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217731 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-13 21:46:00 +00:00
Nick Kledzik
a240fc5cb9 [llvm-objdump] support -rebase option for mach-o to dump rebasing info
Similar to my previous -exports-trie option, the -rebase option dumps info from
the LC_DYLD_INFO load command. The rebasing info is a list of the the locations
that dyld needs to adjust if a mach-o image is not loaded at its preferred 
address. Since ASLR is now the default, images almost never load at their
preferred address, and thus need to be rebased by dyld.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217709 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-12 21:34:15 +00:00
Ehsan Akhgari
97688c4ee3 Add an overload of getLastArgNoClaim taking two OptSpecifiers.
Summary: This will be used in clang.

Test Plan: Will be tested on the clang side.

Reviewers: hansw

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5337

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217702 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-12 19:42:53 +00:00
JF Bastien
5223ff81f5 Add support for le64.
Summary:
le64 is a generic little-endian 64-bit processor, mimicking le32.

Depends on D5318.

Test Plan: make check-all

Reviewers: dschuff

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5319

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217697 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-12 17:54:17 +00:00
NAKAMURA Takumi
81d53b7290 Move sys::fs::AccessMode out of @brief in the function. [-Wdocumentation]
FIXME: Annotate sys::fs::AccessMode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217685 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-12 15:12:32 +00:00
NAKAMURA Takumi
3b59cfdddc sys::fs::access(): Fix @param [-Wdocumentation]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217684 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-12 15:12:21 +00:00
Justin Bogner
8f3096162c llvm-cov: Move FunctionCoverageMapping into CoverageMapping.h (NFC)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217657 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-12 06:52:44 +00:00
David Majnemer
ddf2ec4d4b Object: Small cleanup in COFFObjectFile::getSymbol
NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217648 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-11 23:42:10 +00:00
Rui Ueyama
d76b9eff06 [Support][Endian] Overload += and -=
This patch is to overload operator+= and operator-= for
{u}{little}{big}{16,32,64}_t.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217637 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-11 22:55:25 +00:00
Rui Ueyama
f70f3d4708 Support: Delete {aligned_,}{u,}{little,big}8_t
The byte has no endianness, so these types don't make sense.
uint8_t should be used instead.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217631 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-11 21:46:33 +00:00
Juergen Ributzka
4be836d563 [C API] Make the 'lower switch' pass available via the C API.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217630 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-11 21:32:32 +00:00
Rafael Espindola
8d230cd536 Misc cleanups to the FileSytem api.
The main difference is the removal of

std::error_code exists(const Twine &path, bool &result);

It was an horribly redundant interface since a file not existing is also a valid
error_code. Now we have an access function that returns just an error_code. This
is the only function that has to be implemented for Unix and Windows. The
functions can_write, exists and can_execute an now just wrappers.

One still has to be very careful using these function to avoid introducing
race conditions (Time of check to time of use).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217625 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-11 20:30:02 +00:00
David Blaikie
b946886d1c Use CostPool::PoolRef typedef some more
Cleanup to 217563 suggested by Lang Hames in post-commit review.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217564 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-11 00:08:54 +00:00
David Blaikie
c6b38ee178 shared_ptrify ownershp of PoolEntries in PBQP's CostPool
Leveraging both intrusive shared_ptr-ing (std::enable_shared_from_this)
and shared_ptr<T>-owning-U (to allow external users to hold
std::shared_ptr<CostT> while keeping the underlying PoolEntry alive).

The intrusiveness could be removed if we had a weak_set that implicitly
removed items from the set when their underlying data went away.

This /might/ fix an existing memory leak reported by LeakSanitizer in
r217504.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217563 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 23:54:45 +00:00
Rafael Espindola
3b670550ad Add doInitialization/doFinalization to DataLayoutPass.
With this a DataLayoutPass can be reused for multiple modules.

Once we have doInitialization/doFinalization, it doesn't seem necessary to pass
a Module to the constructor.

Overall this change seems in line with the idea of making DataLayout a required
part of Module. With it the only way of having a DataLayout used is to add it
to the Module.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217548 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 21:27:43 +00:00
Hal Finkel
2d818506ed Enable use of __builtin_assume_aligned when self-hosting
Clang/LLVM trunk now have support for __builtin_assume_aligned, turn this &&
into an || so we can use it ourselves.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217545 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 21:06:11 +00:00
Alexey Samsonov
5e4558e5a8 Make CallingConv::ID an alias of "unsigned".
Summary:
Make CallingConv::ID a plain unsigned instead of enum with a
fixed set of valus. LLVM IR allows arbitraty calling conventions (you are
free to write cc12345), and loading them as enum is an undefined
behavior. This was reported by UBSan.

Test Plan: llvm regression test suite

Reviewers: nicholas

Reviewed By: nicholas

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5248

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217529 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 18:00:17 +00:00
Sanjay Patel
87c977a52b Rename getMaximumUnrollFactor -> getMaxInterleaveFactor; also rename option names controlling this variable.
"Unroll" is not the appropriate name for this variable. Clang already uses 
the term "interleave" in pragmas and metadata for this.

Differential Revision: http://reviews.llvm.org/D5066



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217528 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 17:58:16 +00:00
Gerolf Hoflehner
9d01d42bc4 Added missing blank
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217526 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 17:52:27 +00:00
David Majnemer
8c6dda0b7d Attempt to pacify buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217499 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 13:01:03 +00:00
David Majnemer
b3a86a097b Object: Add support for bigobj
This adds support for reading the "bigobj" variant of COFF produced by
cl's /bigobj and mingw's -mbig-obj.

The most significant difference that bigobj brings is more than 2**16
sections to COFF.

bigobj brings a few interesting differences with it:
- It doesn't have a Characteristics field in the file header.
- It doesn't have a SizeOfOptionalHeader field in the file header (it's
  only used in executable files).
- Auxiliary symbol records have the same width as a symbol table entry.
  Since symbol table entries are bigger, so are auxiliary symbol
  records.

Write support will come soon.

Differential Revision: http://reviews.llvm.org/D5259

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217496 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 12:51:52 +00:00
Yaron Keren
b4c17e7b51 FunctionPassManager isn't used by the JIT anymore, it is used in
clang EmitAssemblyHelper::CreatePasses() in BackendUtil.cpp.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217488 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 10:48:06 +00:00
Yuri Gorshenin
ca31084292 [asan-assembly-instrumentation] Added CFI directives to the generated instrumentation code.
Summary: [asan-assembly-instrumentation] Added CFI directives to the generated instrumentation code.

Reviewers: eugenis

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5189

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217482 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-10 09:45:49 +00:00
Diego Novillo
40c949a1b4 Re-factor sample profile reader into lib/ProfileData.
Summary:
This patch moves the profile reading logic out of the Sample Profile
transformation into a generic profile reader facility in
lib/ProfileData.

The intent is to use this new reader to implement a sample profile
reader/writer that can be used to convert sample profiles from external
sources into LLVM.

This first patch introduces no functional changes. It moves the profile
reading code from lib/Transforms/SampleProfile.cpp into
lib/ProfileData/SampleProfReader.cpp.

In subsequent patches I will:

- Add a bitcode format for sample profiles to allow for more efficient
  encoding of the profile.
- Add a writer for both text and bitcode format profiles.
- Add a 'convert' command to llvm-profdata to be able to convert between
  the two (and serve as entry point for other sample profile formats).

Reviewers: bogner, echristo

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5250

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217437 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-09 12:40:50 +00:00
Justin Bogner
39d5e80b44 llvm-cov: Combine two types that were nearly identical (NFC)
llvm-cov had a SourceRange type that was nearly identical to a
CountedRegion except that it shaved off a couple of fields. There
aren't likely to be enough of these for the minor memory savings to be
worth the extra complexity here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217417 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-09 05:32:18 +00:00
Justin Bogner
74a60259a5 llvm-cov: Rename MappingRegion to coverage::CountedRegion (NFC)
This name was too similar to CoverageMappingRegion, and the type
really belongs in the coverage library anyway.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217416 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-09 05:32:14 +00:00
Justin Bogner
78834e522f llvm-cov: Use ErrorOr rather than an error_code* (NFC)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217404 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-08 21:04:00 +00:00
Hans Wennborg
4cd53531fd Fast-ISel: Remove dead code after falling back from selecting call instructions (PR20863)
Previously, fast-isel would not clean up after failing to select a call
instruction, because it would have called flushLocalValueMap() which moves
the insertion point, making SavedInsertPt in selectInstruction() invalid.

Fixing this by making SavedInsertPt a member variable, and having
flushLocalValueMap() update it.

This removes some redundant code at -O0, and more importantly fixes PR20863.

Differential Revision: http://reviews.llvm.org/D5249

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217401 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-08 20:24:10 +00:00
Hal Finkel
beeca54864 Don't static_cast invalid pointers
UBSan complained about using static_cast on the invalid (tombstone, etc.)
pointers used by DenseMap. Use a reinterpret_cast instead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217397 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-08 19:31:25 +00:00
Alexey Samsonov
e769dc39fd Be more careful in parsing Module::ModFlagBehavior value
to make sure we don't do invalid load of an enum. Share the
conversion code between llvm::Module implementation and the
verifier.

This bug was reported by UBSan.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217395 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-08 19:16:28 +00:00
Chad Rosier
b30d031de4 [AArch64] Improve AA to remove unneeded edges in the AA MI scheduling graph.
Patch by Sanjin Sijaric <ssijaric@codeaurora.org>!
Phabricator Review: http://reviews.llvm.org/D5103

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217371 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-08 14:43:48 +00:00
Hal Finkel
3ef1aae2b5 Make use of @llvm.assume from LazyValueInfo
This change teaches LazyValueInfo to use the @llvm.assume intrinsic. Like with
the known-bits change (r217342), this requires feeding a "context" instruction
pointer through many functions. Aside from a little refactoring to reuse the
logic that turns predicates into constant ranges in LVI, the only new code is
that which can 'merge' the range from an assumption into that otherwise
computed. There is also a small addition to JumpThreading so that it can have
LVI use assumptions in the same block as the comparison feeding a conditional
branch.

With this patch, we can now simplify this as expected:
int foo(int a) {
  __builtin_assume(a > 5);
  if (a > 3) {
    bar();
    return 1;
  }
  return 0;
}

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217345 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-07 20:29:59 +00:00
Hal Finkel
1d6c2d717d Add an AlignmentFromAssumptions Pass
This adds a ScalarEvolution-powered transformation that updates load, store and
memory intrinsic pointer alignments based on invariant((a+q) & b == 0)
expressions. Many of the simple cases we can get with ValueTracking, but we
still need something like this for the more complicated cases (such as those
with an offset) that require some algebra. Note that gcc's
__builtin_assume_aligned's optional third argument provides exactly for this
kind of 'misalignment' offset for which this kind of logic is necessary.

The primary motivation is to fixup alignments for vector loads/stores after
vectorization (and unrolling). This pass is added to the optimization pipeline
just after the SLP vectorizer runs (which, admittedly, does not preserve SE,
although I imagine it could).  Regardless, I actually don't think that the
preservation matters too much in this case: SE computes lazily, and this pass
won't issue any SE queries unless there are any assume intrinsics, so there
should be no real additional cost in the common case (SLP does preserve DT and
LoopInfo).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217344 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-07 20:05:11 +00:00
Hal Finkel
851b04c920 Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.)
This change, which allows @llvm.assume to be used from within computeKnownBits
(and other associated functions in ValueTracking), adds some (optional)
parameters to computeKnownBits and friends. These functions now (optionally)
take a "context" instruction pointer, an AssumptionTracker pointer, and also a
DomTree pointer, and most of the changes are just to pass this new information
when it is easily available from InstSimplify, InstCombine, etc.

As explained below, the significant conceptual change is that known properties
of a value might depend on the control-flow location of the use (because we
care that the @llvm.assume dominates the use because assumptions have
control-flow dependencies). This means that, when we ask if bits are known in a
value, we might get different answers for different uses.

The significant changes are all in ValueTracking. Two main changes: First, as
with the rest of the code, new parameters need to be passed around. To make
this easier, I grouped them into a structure, and I made internal static
versions of the relevant functions that take this structure as a parameter. The
new code does as you might expect, it looks for @llvm.assume calls that make
use of the value we're trying to learn something about (often indirectly),
attempts to pattern match that expression, and uses the result if successful.
By making use of the AssumptionTracker, the process of finding @llvm.assume
calls is not expensive.

Part of the structure being passed around inside ValueTracking is a set of
already-considered @llvm.assume calls. This is to prevent a query using, for
example, the assume(a == b), to recurse on itself. The context and DT params
are used to find applicable assumptions. An assumption needs to dominate the
context instruction, or come after it deterministically. In this latter case we
only handle the specific case where both the assumption and the context
instruction are in the same block, and we need to exclude assumptions from
being used to simplify their own ephemeral values (those which contribute only
to the assumption) because otherwise the assumption would prove its feeding
comparison trivial and would be removed.

This commit adds the plumbing and the logic for a simple masked-bit propagation
(just enough to write a regression test). Future commits add more patterns
(and, correspondingly, more regression tests).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217342 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-07 18:57:58 +00:00
Hal Finkel
3d03d60ca8 Add functions for finding ephemeral values
This adds a set of utility functions for collecting 'ephemeral' values. These
are LLVM IR values that are used only by @llvm.assume intrinsics (directly or
indirectly), and thus will be removed prior to code generation, implying that
they should be considered free for certain purposes (like inlining). The
inliner's cost analysis, and a few other passes, have been updated to account
for ephemeral values using the provided functionality.

This functionality is important for the usability of @llvm.assume, because it
limits the "non-local" side-effects of adding llvm.assume on inlining, loop
unrolling, etc. (these are hints, and do not generate code, so they should not
directly contribute to estimates of execution cost).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217335 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-07 13:49:57 +00:00
Hal Finkel
3666e7f4c1 Add an Assumption-Tracking Pass
This adds an immutable pass, AssumptionTracker, which keeps a cache of
@llvm.assume call instructions within a module. It uses callback value handles
to keep stale functions and intrinsics out of the map, and it relies on any
code that creates new @llvm.assume calls to notify it of the new instructions.
The benefit is that code needing to find @llvm.assume intrinsics can do so
directly, without scanning the function, thus allowing the cost of @llvm.assume
handling to be negligible when none are present.

The current design is intended to be lightweight. We don't keep track of
anything until we need a list of assumptions in some function. The first time
this happens, we scan the function. After that, we add/remove @llvm.assume
calls from the cache in response to registration calls and ValueHandle
callbacks.

There are no new direct test cases for this pass, but because it calls it
validation function upon module finalization, we'll pick up detectable
inconsistencies from the other tests that touch @llvm.assume calls.

This pass will be used by follow-up commits that make use of @llvm.assume.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217334 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-07 12:44:26 +00:00