Introduce an Address type to bundle a pointer value with an
alignment. Introduce APIs on CGBuilderTy to work with Address
values. Change core APIs on CGF/CGM to traffic in Address where
appropriate. Require alignments to be non-zero. Update a ton
of code to compute and propagate alignment information.
As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment
helper function to CGF and made use of it in a number of places in
the expression emitter.
The end result is that we should now be significantly more correct
when performing operations on objects that are locally known to
be under-aligned. Since alignment is not reliably tracked in the
type system, there are inherent limits to this, but at least we
are no longer confused by standard operations like derived-to-base
conversions and array-to-pointer decay. I've also fixed a large
number of bugs where we were applying the complete-object alignment
to a pointer instead of the non-virtual alignment, although most of
these were hidden by the very conservative approach we took with
member alignment.
Also, because IRGen now reliably asserts on zero alignments, we
should no longer be subject to an absurd but frustrating recurring
bug where an incomplete type would report a zero alignment and then
we'd naively do a alignmentAtOffset on it and emit code using an
alignment equal to the largest power-of-two factor of the offset.
We should also now be emitting much more aggressive alignment
attributes in the presence of over-alignment. In particular,
field access now uses alignmentAtOffset instead of min.
Several times in this patch, I had to change the existing
code-generation pattern in order to more effectively use
the Address APIs. For the most part, this seems to be a strict
improvement, like doing pointer arithmetic with GEPs instead of
ptrtoint. That said, I've tried very hard to not change semantics,
but it is likely that I've failed in a few places, for which I
apologize.
ABIArgInfo now always carries the assumed alignment of indirect and
indirect byval arguments. In order to cut down on what was already
a dauntingly large patch, I changed the code to never set align
attributes in the IR on non-byval indirect arguments. That is,
we still generate code which assumes that indirect arguments have
the given alignment, but we don't express this information to the
backend except where it's semantically required (i.e. on byvals).
This is likely a minor regression for those targets that did provide
this information, but it'll be trivial to add it back in a later
patch.
I partially punted on applying this work to CGBuiltin. Please
do not add more uses of the CreateDefaultAligned{Load,Store}
APIs; they will be going away eventually.
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every time it's called rather than attempting to cache the result.
It's unlikely to be called frequently and the overhead of using
it in the first place is already factored out.
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the main attribute and cache the results so we don't have to parse
a single attribute more than once.
This reapplies r246596 with a fix for an uninitialized class member,
and a couple of cleanups and formatting changes.
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This is failing in release mode. Revert while I figure out what's happening.
This reverts commit r246596.
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the main attribute and cache the results so we don't have to parse
a single attribute more than once.
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Also:
- Add a typedef to make working with the result easier.
- Update callers to use the new function.
- Make initFeatureMap out of line.
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A couple of changes here:
a) Do less work in the case where we don't have a target attribute on the
function. We've already canonicalized the attributes for the function -
no need to do more work.
b) Use the newer canonicalized feature adding functions from TargetInfo
to do the work when we do have a target attribute. This enables us to diagnose
some warnings in the case of conflicting written attributes (only ppc does
this today) and also make sure to get all of the features for a cpu that's
listed rather than just change the cpu.
Updated all testcases accordingly and added a new testcase to verify that we'll
error out on ppc if we have some incompatible options using the existing diagnosis
framework there.
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In llvm commit r243581, a reverse range adapter was added which allows
us to change code such as
for (auto I = Fields.rbegin(), E = Fields.rend(); I != E; ++I) {
in to
for (const FieldDecl *I : llvm::reverse(Fields))
This commit changes a few of the places in clang which are eligible to use
this new adapter.
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The attribute '__declspec(noalias)' communicates that the function only
accesses memory pointed to by its pointer-typed arguments.
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- Make it a proper random access iterator with a little help from iterator_adaptor_base
- Clean up users of magic dereferencing. The iterator should behave like an Expr **.
- Make it an implementation detail of Stmt. This allows inlining of the assertions.
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Code in CGCall.cpp that loads up function arguments that need to be
coerced to a different type may in some cases ignore the fact that
the source of the argument is not naturally aligned. This may cause
incorrect code to be generated. In some places in CreateCoercedLoad,
we already have setAlignment calls to address this, but I ran into one
where it was missing, causing wrong code generation on SystemZ.
However, in that location, we do not actually know what alignment of
the source location we can rely on; the callers do not pass anything
to this routine. This is already an issue in other places in
CreateCoercedLoad; and the same problem exists for CreateCoercedStore.
To avoid pessimising code, and to fix the FIXMEs already in place,
this patch also adds an alignment argument to the CreateCoerced*
routines and uses it instead of forcing an alignment of 1. The
callers are changed to pass in the best information they have.
This actually requires changes in a number of existing test cases
since we now get better alignment in many places.
Differential Revision: http://reviews.llvm.org/D11033
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Use const auto rather than duplicating the type name and fix the
error message when the attribute is applied to an incorrect entity.
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This allows us to deal a bit more gracefully with inclusions done
by macros, token pasting, or just code layout/formatting.
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This is needed to use clang's command line option "-ftrap-function" for LTO and
enable changing the trap function name on a per-call-site basis.
rdar://problem/21225723
Differential Revision: http://reviews.llvm.org/D10831
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While there replace stable_sort of std::string with just sort, stability
is not necessary for "simple" value types. No functional change intended.
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in order to make testing somewhat more feasible. Has the advantage
of making it easier to find target features as well.
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using a string map to canonicalize. Fix up a couple of testcases
that needed changing since we are no longer simply appending features
to the list, but all of their mask dependencies as well.
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The patch is generated using this command:
$ tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
work/llvm/tools/clang
To reduce churn, not touching namespaces spanning less than 10 lines.
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If llvm.lifetime.end turns out to be the first instruction in the last
basic block, we can decrement the iterator twice, going past rend.
At the moment, this can never happen because llvm.lifetime.end always
goes immediately after bitcast, but relying on this is very brittle.
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Right now we're ignoring the fpmath attribute since there's no
backend support for a feature like this and to do so would require
checking the validity of the strings and doing general subtarget
feature parsing of valid and invalid features with the target
attribute feature.
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Modeled after the gcc attribute of the same name, this feature
allows source level annotations to correspond to backend code
generation. In llvm particular parlance, this allows the adding
of subtarget features and changing the cpu for a particular function
based on source level hints.
This has been added into the existing support for function level
attributes without particular verification for any target outside
of whether or not the backend will support the features/cpu given
(similar to section, etc).
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Re-land the change r238200, but with modifications in the tests that should
prevent new failures in some environments as reported with the original
change on the mailing list.
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John McCall