Summary:
The sample profiler pass emits several error messages. Instead of
just aborting the compiler with report_fatal_error, we can emit
better messages using DiagnosticInfo.
This adds a new sub-class of DiagnosticInfo to handle the sample
profiler.
Reviewers: chandlerc, qcolombet
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D3086
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by ignoring globals from __TEXT,__cstring,cstring_literals during instrumenation.
Add a regression test.
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bitcast between pointers of two different address spaces if they happened to have
the same pointer size.
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O(N*log(N)). The idea is to introduce total ordering among functions set.
That allows to build binary tree and perform function look-up procedure in O(log(N)) time.
This patch description:
Introduced total ordering among Type instances. Actually it is improvement for existing
isEquivalentType.
0. Coerce pointer of 0 address space to integer.
1. If left and right types are equal (the same Type* value), return 0 (means equal).
2. If types are of different kind (different type IDs). Return result of type IDs
comparison, treating them as numbers.
3. If types are vectors or integers, return result of its
pointers comparison (casted to numbers).
4. Check whether type ID belongs to the next group:
* Void
* Float
* Double
* X86_FP80
* FP128
* PPC_FP128
* Label
* Metadata
If so, return 0.
5. If left and right are pointers, return result of address space
comparison (numbers comparison).
6. If types are complex.
Then both LEFT and RIGHT will be expanded and their element types will be checked with
the same way. If we get Res != 0 on some stage, return it. Otherwise return 0.
7. For all other cases put llvm_unreachable.
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This allows us to generate table lookups for code such as:
unsigned test(unsigned x) {
switch (x) {
case 100: return 0;
case 101: return 1;
case 103: return 2;
case 105: return 3;
case 107: return 4;
case 109: return 5;
case 110: return 6;
default: return f(x);
}
}
Since cases 102, 104, etc. are not constants, the lookup table has holes
in those positions. We therefore guard the table lookup with a bitmask check.
Patch by Jasper Neumann!
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There's a bit of duplicated "magic" code in opt.cpp and Clang's CodeGen that
computes the inliner threshold from opt level and size opt level.
This patch moves the code to a function that lives alongside the inliner itself,
providing a convenient overload to the inliner creation.
A separate patch can be committed to Clang to use this once it's committed to
LLVM. Standalone tools that use the inlining pass can also avoid duplicating
this code and fearing it will go out of sync.
Note: this patch also restructures the conditinal logic of the computation to
be cleaner.
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After r203553 overflow intrinsics and their non-intrinsic (normal)
instruction get hashed to the same value. This patch prevents PRE from
moving an instruction into a predecessor block, and trying to add a phi
node that gets two different types (the intrinsic result and the
non-intrinsic result), resulting in a failing assert.
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The syntax for "cmpxchg" should now look something like:
cmpxchg i32* %addr, i32 42, i32 3 acquire monotonic
where the second ordering argument gives the required semantics in the case
that no exchange takes place. It should be no stronger than the first ordering
constraint and cannot be either "release" or "acq_rel" (since no store will
have taken place).
rdar://problem/15996804
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When an overflow intrinsic is followed by a non-overflow instruction,
replace the latter with an extract. For example:
%sadd = tail call { i32, i1 } @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
%sadd3 = add i32 %a, %b
Here the add statement will be replaced by an extract.
When an overflow intrinsic follows a non-overflow instruction, a clone
of the intrinsic is inserted before the normal instruction, which makes
it the same as the previous case. Subsequent runs of GVN can then clean
up the duplicate instructions and insert the extract.
This fixes PR8817.
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Summary:
When the sample profiles include discriminator information,
use the discriminator values to distinguish instruction weights
in different basic blocks.
This modifies the BodySamples mapping to map <line, discriminator> pairs
to weights. Instructions on the same line but different blocks, will
use different discriminator values. This, in turn, means that the blocks
may have different weights.
Other changes in this patch:
- Add tests for positive values of line offset, discriminator and samples.
- Change data types from uint32_t to unsigned and int and do additional
validation.
Reviewers: chandlerc
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D2857
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optimize a call to a llvm intrinsic to something that invovles a call to a C
library call, make sure it sets the right calling convention on the call.
e.g.
extern double pow(double, double);
double t(double x) {
return pow(10, x);
}
Compiles to something like this for AAPCS-VFP:
define arm_aapcs_vfpcc double @t(double %x) #0 {
entry:
%0 = call double @llvm.pow.f64(double 1.000000e+01, double %x)
ret double %0
}
declare double @llvm.pow.f64(double, double) #1
Simplify libcall (part of instcombine) will turn the above into:
define arm_aapcs_vfpcc double @t(double %x) #0 {
entry:
%__exp10 = call double @__exp10(double %x) #1
ret double %__exp10
}
declare double @__exp10(double)
The pre-instcombine code works because calls to LLVM builtins are special.
Instruction selection will chose the right calling convention for the call.
However, the code after instcombine is wrong. The call to __exp10 will use
the C calling convention.
I can think of 3 options to fix this.
1. Make "C" calling convention just work since the target should know what CC
is being used.
This doesn't work because each function can use different CC with the "pcs"
attribute.
2. Have Clang add the right CC keyword on the calls to LLVM builtin.
This will work but it doesn't match the LLVM IR specification which states
these are "Standard C Library Intrinsics".
3. Fix simplify libcall so the resulting calls to the C routines will have the
proper CC keyword. e.g.
%__exp10 = call arm_aapcs_vfpcc double @__exp10(double %x) #1
This works and is the solution I implemented here.
Both solutions #2 and #3 would work. After carefully considering the pros and
cons, I decided to implement #3 for the following reasons.
1. It doesn't change the "spec" of the intrinsics.
2. It's a self-contained fix.
There are a couple of potential downsides.
1. There could be other places in the optimizer that is broken in the same way
that's not addressed by this.
2. There could be other calling conventions that need to be propagated by
simplify-libcall that's not handled.
But for now, this is the fix that I'm most comfortable with.
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This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
detail
2) Change it to actually be a *Use* iterator rather than a *User*
iterator.
3) Add an adaptor which is a User iterator that always looks through the
Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
they wanted a use_iterator (and to explicitly dig out the User when
needed), or a user_iterator which makes the Use itself totally
opaque.
Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.
The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.
However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]
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Sequences of insertelement/extractelements are sometimes used to build
vectorsr; this code tries to put them back together into shuffles, but
could only produce a completely uniform shuffle types (<N x T> from two
<N x T> sources).
This should allow shuffles with different numbers of elements on the
input and output sides as well.
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This compiles with no changes to clang/lld/lldb with MSVC and includes
overloads to various functions which are used by those projects and llvm
which have OwningPtr's as parameters. This should allow out of tree
projects some time to move. There are also no changes to libs/Target,
which should help out of tree targets have time to move, if necessary.
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already lived there and it is where it belongs -- this is the in-memory
debug location representation.
This is just cleanup -- Modules can actually cope with this, but that
doesn't make it right. After chatting with folks that have out-of-tree
stuff, going ahead and moving the rest of the headers seems preferable.
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to ensure we don't mess up any of the overrides. Necessary for cleaning
up the Value use iterators and enabling range-based traversing of use
lists.
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a bit surprising, as the class is almost entirely abstracted away from
any particular IR, however it encodes the comparsion predicates which
mutate ranges as ICmp predicate codes. This is reasonable as they're
used for both instructions and constants. Thus, it belongs in the IR
library with instructions and constants.
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this would have been required because of the use of DataLayout, but that
has moved into the IR proper. It is still required because this folder
uses the constant folding in the analysis library (which uses the
datalayout) as the more aggressive basis of its folder.
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directly care about the Value class (it is templated so that the key can
be any arbitrary Value subclass), it is in fact concretely tied to the
Value class through the ValueHandle's CallbackVH interface which relies
on the key type being some Value subclass to establish the value handle
chain.
Ironically, the unittest is already in the right library.
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Move the test for this class into the IR unittests as well.
This uncovers that ValueMap too is in the IR library. Ironically, the
unittest for ValueMap is useless in the Support library (honestly, so
was the ValueHandle test) and so it already lives in the IR unittests.
Mmmm, tasty layering.
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name might indicate, it is an iterator over the types in an instruction
in the IR.... You see where this is going.
Another step of modularizing the support library.
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business.
This header includes Function and BasicBlock and directly uses the
interfaces of both classes. It has to do with the IR, it even has that
in the name. =] Put it in the library it belongs to.
This is one step toward making LLVM's Support library survive a C++
modules bootstrap.
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DWARF discriminators are used to distinguish multiple control flow paths
on the same source location. When this happens, instructions across
basic block boundaries will share the same debug location.
This pass detects this situation and creates a new lexical scope to one
of the two instructions. This lexical scope is a child scope of the
original and contains a new discriminator value. This discriminator is
then picked up from MCObjectStreamer::EmitDwarfLocDirective to be
written on the object file.
This fixes http://llvm.org/bugs/show_bug.cgi?id=18270.
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remove_if that its predicate is adaptable. We don't actually need this,
we can write a generic adapter for any predicate.
This lets us remove some very wrong std::function usages. We should
never be using std::function for predicates to algorithms. This incurs
an *indirect* call overhead for every evaluation of the predicate, and
makes it very hard to inline through.
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operand_values. The first provides a range view over operand Use
objects, and the second provides a range view over the Value*s being
used by those operands.
The naming is "STL-style" rather than "LLVM-style" because we have
historically named iterator methods STL-style, and range methods seem to
have far more in common with their iterator counterparts than with
"normal" APIs. Feel free to bikeshed on this one if you want, I'm happy
to change these around if people feel strongly.
I've switched code in SROA and LCG to exercise these mostly to ensure
they work correctly -- we don't really have an easy way to unittest this
and they're trivial.
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address spaces.
This isn't really a correctness issue (the values are truncated) but its
much cleaner.
Patch by Matt Arsenault!
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the default.
Based on the patch by Matt Arsenault, D1764!
I switched one place to use the more direct pointer type to compute the
desired address space, and I reworked the memcpy rewriting section to
reflect significant refactorings that this patch helped inspire.
Thanks to several of the folks who helped review and improve the patch
as well.
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to work independently for the slice side and the other side.
This allows us to only compute the minimum of the two when we actually
rewrite to a memcpy that needs to take the minimum, and preserve higher
alignment for one side or the other when rewriting to loads and stores.
This fix was inspired by seeing the result of some refactoring that
makes addrspace handling better.
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D1764, which in turn set off the other refactorings to make
'getSliceAlign()' a sensible thing.
There are two possible inputs to the required alignment of a memory
transfer intrinsic: the alignment constraints of the source and the
destination. If we are *only* introducing a (potentially new) offset
onto one side of the transfer, we don't need to consider the alignment
constraints of the other side. Use this to simplify the logic feeding
into alignment computation for unsplit transfers.
Also, hoist the clamp of the magical zero alignment for these intrinsics
to the more customary one alignment early. This lets several other
conditions melt away.
No functionality changed. There is a further improvement this exposes
which *will* change functionality, but that's arriving in a separate
patch.
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rewriting logic: don't pass custom offsets for the adjusted pointer to
the new alloca.
We always passed NewBeginOffset here. Sometimes we spelled it
BeginOffset, but only when they were in fact equal. Whats worse, the API
is set up so that you can't reasonably call it with anything else -- it
assumes that you're passing it an offset relative to the *original*
alloca that happens to fall within the new one. That's the whole point
of NewBeginOffset, it's the clamped beginning offset.
No functionality changed.
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alignment of the slice being rewritten, not any arbitrary offset.
Every caller is really just trying to compute the alignment for the
whole slice, never for some arbitrary alignment. They are also just
passing a type when they have one to see if we can skip an explicit
alignment in the IR by using the type's alignment. This makes for a much
simpler interface.
Another refactoring inspired by the addrspace patch for SROA, although
only loosely related.
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consistency with memcpy rewriting, and fix a latent bug in the alignment
management for memset.
The alignment issue is that getAdjustedAllocaPtr is computing the
*relative* offset into the new alloca, but the alignment isn't being set
to the relative offset, it was using the the absolute offset which is
into the old alloca.
I don't think its possible to write a test case that actually reaches
this code where the resulting alignment would be observably different,
but the intent was clearly to use the relative offset within the new
alloca.
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rather than passing them as arguments.
While I generally prefer actual arguments, in this case the readability
loss is substantial. By using members we avoid repeatedly calculating
the offsets, and once we're using members it is useful to ensure that
those names *always* refer to the original-alloca-relative new offset
for a rewritten slice.
No functionality changed. Follow-up refactoring, all toward getting the
address space patch merged.
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slice being rewritten.
We had the same code scattered across most of the visits. Instead,
compute the new offsets and the slice size once when we start to visit
a particular slice, and use the member variables from then on. This
reduces quite a bit of code duplication.
No functionality changed. Refactoring inspired to make it easier to
apply the address space patch to SROA.
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checking in SROA.
The primary change is to just rely on uge for checking that the offset
is within the allocation size. This removes the explicit checks against
isNegative which were terribly error prone (including the reversed logic
that led to PR18615) and prevented us from supporting stack allocations
larger than half the address space.... Ok, so maybe the latter isn't
*common* but it's a silly restriction to have.
Also, we used to try to support a PHI node which loaded from before the
start of the allocation if any of the loaded bytes were within the
allocation. This doesn't make any sense, we have never really supported
loading or storing *before* the allocation starts. The simplified logic
just doesn't care.
We continue to allow loading past the end of the allocation in part to
support cases where there is a PHI and some loads are larger than others
and the larger ones reach past the end of the allocation. We could solve
this a different and more conservative way, but I'm still somewhat
paranoid about this.
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their inputs come from std::stable_sort and they are not total orders.
I'm not a huge fan of this, but the really bad std::stable_sort is right
at the beginning of Reassociate. After we commit to stable-sort based
consistent respect of source order, the downstream sorts shouldn't undo
that unless they have a total order or they are used in an
order-insensitive way. Neither appears to be true for these cases.
I don't have particularly good test cases, but this jumped out by
inspection when looking for output instability in this pass due to
changes in the ordering of std::sort.
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implemented this way a long time ago and due to the overwhelming bugs
that surfaced, moved to a much more relaxed variant. Richard Smith would
like to understand the magnitude of this problem and it seems fairly
harmless to keep some flag-controlled logic to get the extremely strict
behavior here. I'll remove it if it doesn't prove useful.
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Instead, have a DataLayoutPass that holds one. This will allow parts of LLVM
don't don't handle passes to also use DataLayout.
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just "load". This helps avoid pointless de-duping with order-sensitive
numbers as we already have unique names from the original load. It also
makes the resulting IR quite a bit easier to read.
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the pointer adjustment code. This is the primary code path that creates
totally new instructions in SROA and being able to lump them based on
the pointer value's name for which they were created causes
*significantly* fewer name collisions and general noise in the debug
output. This is particularly significant because it is making it much
harder to track down instability in the output of SROA, as name
de-duplication is a totally harmless form of instability that gets in
the way of seeing real problems.
The new fancy naming scheme tries to dig out the root "pre-SROA" name
for pointer values and associate that all the way through the pointer
formation instructions. Digging out the root is important to prevent the
multiple iterative rounds of SROA from just layering too much cruft on
top of cruft here. We already track the layers of SROAs iteration in the
alloca name prefix. We don't need to duplicate it here.
Should have no functionality change, and shouldn't have any really
measurable impact on NDEBUG builds, as most of the complex logic is
debug-only.
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using OldPtr more heavily. Lots of this code was written before the
rewriter had an OldPtr member setup ahead of time. There are already
asserts in place that should ensure this doesn't change any
functionality.
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the break statement, not just think it to yourself....
No idea how this worked at all, much less survived most bots, my
bootstrap, and some bot bootstraps!
The Polly one didn't survive, and this was filed as PR18959. I don't
have a reduced test case and honestly I'm not seeing the need. What we
probably need here are better asserts / debug-build behavior in
SmallPtrSet so that this madness doesn't make it so far.
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sorting it. This helps uncover latent reliance on the original ordering
which aren't guaranteed to be preserved by std::sort (but often are),
and which are based on the use-def chain orderings which also aren't
(technically) guaranteed.
Only available in C++11 debug builds, and behind a flag to prevent noise
at the moment, but this is generally useful so figured I'd put it in the
tree rather than keeping it out-of-tree.
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the destination operand or source operand of a memmove.
It so happens that it was impossible for SROA to try to rewrite
self-memmove where the operands are *identical*, because either such
a think is volatile (and we don't rewrite) or it is non-volatile, and we
don't even register it as a use of the alloca.
However, making the 'IsDest' test *rely* on this subtle fact is... Very
confusing for the reader. We should use the direct and readily available
test of the Use* which gives us concrete information about which operand
is being rewritten.
No functionality changed, I hope! ;]
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ordering.
The fundamental problem that we're hitting here is that the use-def
chain ordering is *itself* not a stable thing to be relying on in the
rewriting for SROA. Further, we use a non-stable sort over the slices to
arrange them based on the section of the alloca they're operating on.
With a debugging STL implementation (or different implementations in
stage2 and stage3) this can cause stage2 != stage3.
The specific aspect of this problem fixed in this commit deals with the
rewriting and load-speculation around PHIs and Selects. This, like many
other aspects of the use-rewriting in SROA, is really part of the
"strong SSA-formation" that is doen by SROA where it works very hard to
canonicalize loads and stores in *just* the right way to satisfy the
needs of mem2reg[1]. When we have a select (or a PHI) with 2 uses of the
same alloca, we test that loads downstream of the select are
speculatable around it twice. If only one of the operands to the select
needs to be rewritten, then if we get lucky we rewrite that one first
and the select is immediately speculatable. This can cause the order of
operand visitation, and thus the order of slices to be rewritten, to
change an alloca from promotable to non-promotable and vice versa.
The fix is to defer all of the speculation until *after* the rewrite
phase is done. Once we've rewritten everything, we can accurately test
for whether speculation will work (once, instead of twice!) and the
order ceases to matter.
This also happens to simplify the other subtlety of speculation -- we
need to *not* speculate anything unless the result of speculating will
make the alloca fully promotable by mem2reg. I had a previous attempt at
simplifying this, but it was still pretty horrible.
There is actually already a *really* nice test case for this in
basictest.ll, but on multiple STL implementations and inputs, we just
got "lucky". Fortunately, the test case is very small and we can
essentially build it in exactly the opposite way to get reasonable
coverage in both directions even from normal STL implementations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202092 91177308-0d34-0410-b5e6-96231b3b80d8
