This is a small targeted fix for pr20119. The code needs quiet a bit of
refactoring and I added some FIXMEs about it, but I want to get the testcase
passing first.
[PeepholeOptimizer] Advanced rewriting of copies to avoid cross register banks
copies.
This patch extends the peephole optimization introduced in r190713 to produce
register-coalescer friendly copies when possible.
This extension taught the existing cross-bank copy optimization how to deal
with the instructions that generate cross-bank copies, i.e., insert_subreg,
extract_subreg, reg_sequence, and subreg_to_reg.
E.g.
b = insert_subreg e, A, sub0 <-- cross-bank copy
...
C = copy b.sub0 <-- cross-bank copy
Would produce the following code:
b = insert_subreg e, A, sub0 <-- cross-bank copy
...
C = copy A <-- same-bank copy
This patch also introduces a new helper class for that: ValueTracker.
This class implements the logic to look through the copy related instructions
and get the related source.
For now, the advanced rewriting is disabled by default as we are lacking the
semantic on target specific instructions to catch the motivating examples.
[RegAllocGreedy] Provide a flag to disable the local reassignment heuristic.
By default, no functionality change.
Before evicting a local variable, this heuristic tries to find another (set of)
local(s) that can be reassigned to a free color.
In some extreme cases (large basic blocks with tons of local variables), the
compilation time is dominated by the local interference checks that this
heuristic must perform, with no code gen gain.
E.g., the motivating example takes 4 minutes to compile with this heuristic, 12
seconds without.
Improving the situation will likely require to make drastic changes to the
register allocator and/or the interference check framework.
For now, provide this flag to better understand the impact of that heuristic.
Alp Toker [Tue, 1 Jul 2014 03:18:49 +0000 (03:18 +0000)]
ExecutionEngine::create(): fix interpreter fallback when JIT is unavailable
ForceInterpreter=false shouldn't disable the interpreter completely because it
can still be necessary to interpret if the target doesn't support JIT.
No obvious way to test this in LLVM, but this matches what
LLVMCreateExecutionEngineForModule() does and fixes the clang-interpreter
example in the clang source tree which uses the ExecutionEngine.
David Blaikie [Tue, 1 Jul 2014 03:11:59 +0000 (03:11 +0000)]
DebugInfo: Ensure that all debug location scope chains from instructions within a function, lead to the function itself.
Originally committed in r211723, reverted in r211724 due to failure
cases found and fixed (ArgumentPromotion: r211872, Inlining: r212065),
and I now believe the invariant actually holds for some reasonable
amount of code (but I'll keep an eye on the buildbots and see what
happens... ).
Original commit message:
PR20038: DebugInfo: Inlined call sites where the caller has debug info
but the call itself has no debug location.
This situation does bad things when inlined, so I've fixed Clang not to
produce inlinable call sites without locations when the caller has debug
info (in the one case where I could find that this occurred). This
updates the PR20038 test case to be what clang now produces, and readds
the assertion that had to be removed due to this bug.
I've also beefed up the debug info verifier to help diagnose these
issues in the future, and I hope to add checks to the inliner to just
assert-fail if it encounters this situation. If, in the future, we
decide we have to cope with this situation, the right thing to do is
probably to just remove all the DebugLocs from the inlined instructions.
Inlining functions with block addresses can cause many problem and requires a
rich infrastructure to support including escape analysis. At this point the
safest approach to address these problems is by blocking inlining from
happening.
Background:
There have been reports on Ruby segmentation faults triggered by inlining
functions with block addresses like
This kind of scenario can also happen when LLVM picks a subset of blocks for
inlining, which is the case with the actual code in the Ruby environment.
LLVM suppresses inlining for such functions when there is an indirect branch.
The attached patch does so even when there is no indirect branch. Note that
user code like above would not make much sense: using the global for jumping
across function boundaries would be illegal.
Why was there a segfault:
In the snipped above the block with the label is recognized as dead So it is
eliminated. Instead of a block address the cloner stores a constant (sic!) into
the global resulting in the segfault (when the global is used in a goto).
Why had it worked in the past then:
By luck. In older versions vm_exec_core was also inlined but the label address
used was the block label address in vm_exec_core. So the global jump ended up
in the original function rather than in the caller which accidentally happened
to work.
Test case ./tools/clang/test/CodeGen/indirect-goto.c will fail as a result
of this commit.
In r212073 I missed a call of `use_begin()` that assumed the wrong
semantics. It's not clear to me at all what this code does without the
fix, so I'm not sure how to write a testcase.
AArch64AddressTypePromotion was doing nothing because it was using the
old semantics of `Use` and `uses()`, when it really wanted to get at the
`users()`.
David Blaikie [Mon, 30 Jun 2014 20:30:39 +0000 (20:30 +0000)]
DebugInfo: Preserve debug location information when transforming a call into an invoke during inlining.
This both improves basic debug info quality, but also fixes a larger
hole whenever we inline a call/invoke without a location (debug info for
the entire inlining is lost and other badness that the debug info
emission code is currently working around but shouldn't have to).
Kevin Enderby [Mon, 30 Jun 2014 18:45:23 +0000 (18:45 +0000)]
Add the -arch flag support to llvm-nm to select the slice out of a Mach-O
universal file. This also includes support for -arch all, selecting the host
architecture by default from a universal file and checking if -arch is used
with a standard Mach-O it matches that architecture.
Adrian Prantl [Mon, 30 Jun 2014 17:17:35 +0000 (17:17 +0000)]
Debug info: split out complex DIVariable address expressions into a
separate MDNode so they can be uniqued via folding set magic. To conserve
space, DIVariable nodes are still variable-length, with the last two
fields being optional.
No functional change.
http://reviews.llvm.org/D3526
Andrea Di Biagio [Mon, 30 Jun 2014 17:14:21 +0000 (17:14 +0000)]
[X86] Add support for builtin to read performance monitoring counters.
This patch adds support for a new builtin instruction called
__builtin_ia32_rdpmc.
Builtin '__builtin_ia32_rdpmc' is defined as a 'GCC builtin'; on X86, it can
be used to read performance monitoring counters. It takes as input the index
of the performance counter to read, and returns the value of the specified
performance counter as a 64-bit number.
Calls to this new builtin will map to instruction RDPMC.
The index in input to the builtin call is moved to register %ECX. The result
of the builtin call is the value of the specified performance counter (RDPMC
would return that quantity in registers RDX:RAX).
This patch:
- Adds builtin int_x86_rdpmc as a GCCBuiltin;
- Adds a new x86 DAG node called 'RDPMC_DAG';
- Teaches how to lower this new builtin;
- Adds an ISel pattern to select instruction RDPMC;
- Fixes the definition of instruction RDPMC adding %RAX and %RDX as
implicit definitions, and adding %ECX as implicit use;
- Adds a LLVM test to verify that the new builtin is correctly selected.
This exception format is not specific to Windows x64. A similar approach is
taken on nearly all architectures. Generalise the name to reflect reality.
This will eventually be used for Windows on ARM data emission as well.
Rename the routines to reflect the reality that they are more related to call
frame information than to Win64 EH. Although EH is implemented in an intertwined
manner by augmenting with an exception handler and an associated parameter, the
majority of these routines emit information required to unwind the frames. This
also helps identify that these routines are generic for most windows platforms
(they apply equally to nearly all architectures except x86) although the
encoding of the information is architecture dependent.
Unwinding data is emitted via EmitWinCFI* and exception handling information via
EmitWinEH*.
Chandler Carruth [Sat, 28 Jun 2014 05:46:28 +0000 (05:46 +0000)]
[x86] Fix a bug in the v8i16 shuffling exposed by the new splat-like
lowering for v16i8.
ASan and some bots caught this bug with existing test cases. Fixing it
even fixed a miscompile with one of the test cases. I'm still a bit
suspicious of this test case as I've not taken a proper amount of time
to think about it, but the fix here is strict goodness.
Chandler Carruth [Sat, 28 Jun 2014 05:18:49 +0000 (05:18 +0000)]
Fix this test to not write to the source tree, and instead to write to
a temporary file. This fixes the test in cases where the source tree is
mounted read-only.
Chandler Carruth [Sat, 28 Jun 2014 05:16:40 +0000 (05:16 +0000)]
[x86] Add handling for splat-like widenings of v16i8 shuffles.
These show up really frequently, not the least with actual splats. =] We
lowered these quite badly before. The new code path tries to widen i8
shuffles to i16 shuffles in a splat-like way. There are still some
inefficiencies in our i16 splat logic though, so we aren't really done
here.
Also, for certain patterns (bit of a gather-and-splat) we still
generate pretty silly code, and I've left a fixme for addressing it.
However, I'm not actually worried about this code pattern as much. The
old shuffle lowering generates a 29 instruction monstrosity for it that
should execute much more slowly.
Justin Bogner [Fri, 27 Jun 2014 20:41:25 +0000 (20:41 +0000)]
llvm-cov: Support specifying multiple source files
Make llvm-cov compatible with gcov for cases where multiple files are
specified on the command line. That is, loop over each one and report
coverage, and report errors on stderr only rather than via return
code.
Lang Hames [Fri, 27 Jun 2014 20:20:57 +0000 (20:20 +0000)]
[RuntimeDyld] Add a framework for testing relocation logic in RuntimeDyld.
This patch adds a "-verify" mode to the llvm-rtdyld utility. In verify mode,
llvm-rtdyld will test supplied expressions against the linked program images
that it creates in memory. This scheme can be used to verify the correctness
of the relocation logic applied by RuntimeDyld.
The expressions to test will be read out of files passed via the -check option
(there may be more than one of these). Expressions to check are extracted from
lines of the form:
# rtdyld-check: <expression>
This system is designed to fit the llvm-lit regression test workflow. It is
format and target agnostic, and supports verification of images linked for
remote targets. The expression language is defined in
llvm/include/llvm/RuntimeDyldChecker.h . Examples can be found in
test/ExecutionEngine/RuntimeDyld.
Chandler Carruth [Fri, 27 Jun 2014 20:07:40 +0000 (20:07 +0000)]
[x86] Fix another bug hit when bootstrapping with the new shuffle
lowering.
For maximum irony, I had already discovered this bug, diagnosed it, and
left FIXMEs about it in the test cases. =[ I just failed to go back over
those until after i had reduced a bootstrap miscompile down to a single
TU, stared at the assembly for an hour, and figured out the bug. Again.
Aaron Ballman [Fri, 27 Jun 2014 19:05:17 +0000 (19:05 +0000)]
Adding some trailing whitespace after a comment previously ending with \ to ensure that it isn't lexed as a multiline comment. This silences some -Wcomment warnings.
David Majnemer [Fri, 27 Jun 2014 18:19:56 +0000 (18:19 +0000)]
IR: Add COMDATs to the IR
This new IR facility allows us to represent the object-file semantic of
a COMDAT group.
COMDATs allow us to tie together sections and make the inclusion of one
dependent on another. This is required to implement features like MS
ABI VFTables and optimizing away certain kinds of initialization in C++.
This functionality is only representable in COFF and ELF, Mach-O has no
similar mechanism.
Reid Kleckner [Fri, 27 Jun 2014 18:17:30 +0000 (18:17 +0000)]
cmake: Don't do anything for LLVM_ENABLE_ASSERTIONS=OFF
By default, CMake will set NDEBUG in Rel* builds and leave it off in
debug builds, so we shouldn't need to do anything ourselves.
Before this change, it was possible to a Debug build without assertions
(aka Debug-Asserts in the autoconf system) by configuring with
-DLLVM_ENABLE_ASSERTIONS=OFF, but this configuration isn't very useful.
You can still get the same effect by explicitly adding -DNDEBUG to
CFLAGS.
Julien Lerouge [Fri, 27 Jun 2014 18:02:54 +0000 (18:02 +0000)]
lldb can interrupt waitpid, so EINTR shouldn't be an error. This fixes the case
where there is no timeout. In the case where there is a timeout though, the
code is still wrong since it doesn't check that the alarm really went off.
Without this patch, I cannot debug a program that forks itself using
sys::ExecuteAndWait with lldb.
David Majnemer [Fri, 27 Jun 2014 17:19:44 +0000 (17:19 +0000)]
MC: Fix associative sections on COFF
COFF sections in MC were represented by a tuple of section-name and
COMDAT-name. This is not sufficient to represent a .text section
associated with another .text section; we need a way to distinguish
between the key section and the one marked associative.