This patch fixes an issue where Microsoft-specific layout attributes,
such as __declspec(empty_bases), were ignored during CUDA/HIP device
compilation on a Windows host. This caused a critical memory layout
mismatch between host and device objects, breaking libraries that rely
on these attributes for ABI compatibility.
The fix introduces a centralized hasMicrosoftRecordLayout() check within
the TargetInfo class. This check is aware of the auxiliary (host) target
and is set during TargetInfo::adjust if the host uses a Microsoft ABI.
The empty_bases, layout_version, and msvc::no_unique_address attributes
now use this centralized flag, ensuring device code respects them and
maintains layout consistency with the host.
Fixes: https://github.com/llvm/llvm-project/issues/146047
This implements the [[msvc::no_unique_address]] attribute.
There is not ABI compatibility in this patch because the attribute is
relatively new and there's still some uncertainty in the MSVC version.
The recommit changes the attribute definitions so that instead of making
two separate attributes for no_unique_address
and msvc::no_unique_address, it modifies the attributes tablegen emitter
to allow spellings to be target-specific.
This reverts commit 71f9e7695b87298f9855d8890f0e6a3b89381eb5.
This reverts commit 4a55d426967b9c70f5dea7b3a389e11393a4f4c4.
Reverting because this breaks sphinx documentation, and even with it
fixed the format of the attribute makes the no_unique_address
documentation show up twice.
We have a new policy in place making links to private resources
something we try to avoid in source and test files. Normally, we'd
organically switch to the new policy rather than make a sweeping change
across a project. However, Clang is in a somewhat special circumstance
currently: recently, I've had several new contributors run into rdar
links around test code which their patch was changing the behavior of.
This turns out to be a surprisingly bad experience, especially for
newer folks, for a handful of reasons: not understanding what the link
is and feeling intimidated by it, wondering whether their changes are
actually breaking something important to a downstream in some way,
having to hunt down strangers not involved with the patch to impose on
them for help, accidental pressure from asking for potentially private
IP to be made public, etc. Because folks run into these links entirely
by chance (through fixing bugs or working on new features), there's not
really a set of problematic links to focus on -- all of the links have
basically the same potential for causing these problems. As a result,
this is an omnibus patch to remove all such links.
This was not a mechanical change; it was done by manually searching for
rdar, radar, radr, and other variants to find all the various
problematic links. From there, I tried to retain or reword the
surrounding comments so that we would lose as little context as
possible. However, because most links were just a plain link with no
supporting context, the majority of the changes are simple removals.
Differential Review: https://reviews.llvm.org/D158071
The packed attribute can still be useful in this case if the struct is
then placed inside another packed struct - the non-pod element type's
packed attribute declares that it's OK to misalign this element inside
the packed structure. (otherwise the non-pod element is not packed/its
alignment is preserved, as per D117616/2771233)
Fixes PR62353
Differential Revision: https://reviews.llvm.org/D149182
This reverts commit 22e2db6010b029ebd4c6d3d1fd30224d8b3109ef.
Broke buildbots on Windows. It seems standard headers on Windows contain
flexible array members in unions
It was rejected in C, and in a strange way accepted in C++. However, the
support was never properly tested and fully implemented, so just reject
it in C++ mode as well.
This change also fixes crash on attempt to initialize union with flexible
array member. Due to missing check on union, there was a null expression
added to init list that caused crash later.
Fixes https://github.com/llvm/llvm-project/issues/61746
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D147626
alignments
In the following code, the first element is aligned on a 16-byte
boundary, but the remaining elements aren't:
```
typedef char int8_a16 __attribute__((aligned(16)));
int8_a16 array[4];
```
Currently clang doesn't reject the code, but it should since it can
cause crashes at runtime. This patch also fixes assertion failures in
CodeGen caused by the changes in https://reviews.llvm.org/D123649.
Differential Revision: https://reviews.llvm.org/D133711
Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.
The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.
An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.
---
Troubleshooting list to deal with any breakage seen with this patch:
1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.
2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.
3) This patch could expose a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.
4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.
5) It could be a bug in this patch perhaps.
Let me know if you need any help!
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D112374
This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it
stills breaks the LLDB tests. This was re-landed without addressing the
issue or even agreement on how to address the issue. More details and
discussion in https://reviews.llvm.org/D112374.
Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.
The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.
An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.
---
Troubleshooting list to deal with any breakage seen with this patch:
1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.
2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.
3) This patch could exposed a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.
4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.
5) It could be a bug in this patch perhaps.
Let me know if you need any help!
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D112374
This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it
breaks all the LLDB tests that import the std module.
import-std-module/array.TestArrayFromStdModule.py
import-std-module/deque-basic.TestDequeFromStdModule.py
import-std-module/deque-dbg-info-content.TestDbgInfoContentDequeFromStdModule.py
import-std-module/forward_list.TestForwardListFromStdModule.py
import-std-module/forward_list-dbg-info-content.TestDbgInfoContentForwardListFromStdModule.py
import-std-module/list.TestListFromStdModule.py
import-std-module/list-dbg-info-content.TestDbgInfoContentListFromStdModule.py
import-std-module/queue.TestQueueFromStdModule.py
import-std-module/stack.TestStackFromStdModule.py
import-std-module/vector.TestVectorFromStdModule.py
import-std-module/vector-bool.TestVectorBoolFromStdModule.py
import-std-module/vector-dbg-info-content.TestDbgInfoContentVectorFromStdModule.py
import-std-module/vector-of-vectors.TestVectorOfVectorsFromStdModule.py
https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/45301/
Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.
The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.
An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D112374
Based on post-commit review discussion on
2bd84938470bf2e337801faafb8a67710f46429d with Richard Smith.
Other uses of forcing HasEmptyPlaceHolder to false seem OK to me -
they're all around pointer/reference types where the pointer/reference
token will appear at the rightmost side of the left side of the type
name, so they make nested types (eg: the "int" in "int *") behave as
though there is a non-empty placeholder (because the "*" is essentially
the placeholder as far as the "int" is concerned).
This was originally committed in 277623f4d5a672d707390e2c3eaf30a9eb4b075c
Reverted in f9ad1d1c775a8e264bebc15d75e0c6e5c20eefc7 due to breakages
outside of clang - lldb seems to have some strange/strong dependence on
"char [N]" versus "char[N]" when printing strings (not due to that name
appearing in DWARF, but probably due to using clang to stringify type
names) that'll need to be addressed, plus a few other odds and ends in
other subprojects (clang-tools-extra, compiler-rt, etc).
Looks like lldb has some issues with this - somehow it causes lldb to
treat a "char[N]" type as an array of chars (prints them out
individually) but a "char [N]" is printed as a string. (even though the
DWARF doesn't have this string in it - it's something to do with the
string lldb generates for itself using clang)
This reverts commit 277623f4d5a672d707390e2c3eaf30a9eb4b075c.
Based on post-commit review discussion on
2bd84938470bf2e337801faafb8a67710f46429d with Richard Smith.
Other uses of forcing HasEmptyPlaceHolder to false seem OK to me -
they're all around pointer/reference types where the pointer/reference
token will appear at the rightmost side of the left side of the type
name, so they make nested types (eg: the "int" in "int *") behave as
though there is a non-empty placeholder (because the "*" is essentially
the placeholder as far as the "int" is concerned).
The current check for typedef is naive and doesn't deal with any convoluted cases. This patch makes use of the new 'AlignRequirement' enum field from 'TypeInfo' to determine whether or not this is an 'aligned' attribute on a typedef.
Reviewed By: rjmccall
Differential Revision: https://reviews.llvm.org/D109387
The "aligned" attribute can only increase the alignment of a struct, or struct member, unless it's used together with the "packed" attribute, or used as a part of a typedef, in which case, the "aligned" attribute can both increase and decrease alignment.
That said, we expect:
1. "aligned" attribute alone: does not interfere with the alignment upgrade instrumented by the AIX "power" alignment rule,
2. "aligned" attribute + typedef: overrides any computed alignment,
3. "aligned" attribute + "packed" attribute: overrides any computed alignment.
The old implementation achieved 2 and 3, but didn't get 1 right, in that any field marked attribute "aligned" would not go through the alignment upgrade.
Reviewed By: rjmccall
Differential Revision: https://reviews.llvm.org/D107394
`__alignof__(x)` always returns `ABIAlign` if the "x" is marked `__attribute__((aligned()))`. However, the "aligned" attribute should only increase the alignment of a struct, or struct member, unless it's used together with the "packed" attribute, or used as a part of a typedef, in which case, the "aligned" attribute can both increase and decrease alignment.
Reviewed By: sfertile
Differential Revision: https://reviews.llvm.org/D107598
Zero-width bitfields on AIX pad out to the natral alignment boundary but
do not change the containing records alignment.
Differential Revision: https://reviews.llvm.org/D106900
On AIX when there is a pragma pack, or pragma align in effect then zero-width bitfields should pad out to the end of the bitfield container but not increase the alignment requirements of the struct greater then the max field align.
Reviewed By: ZarkoCA
Differential Revision: https://reviews.llvm.org/D105635
This option implies -fdump-record-layouts but dumps record layout information with canonical field types, which can be more useful in certain cases when comparing structure layouts.
Reviewed By: stevewan
Differential Revision: https://reviews.llvm.org/D105112
This change adds an option which, in addition to dumping the record
layout as is done by -fdump-record-layouts, causes us to compute the
layout for all complete record types (rather than the as-needed basis
which is usually done by clang), so that we will dump them as well.
This is useful if we are looking for layout differences across large
code bases without needing to instantiate every type we are interested in.
Reviewed By: dexonsmith
Differential Revision: https://reviews.llvm.org/D104484
1.[bool, char, short] bitfields have the same alignment as unsigned int
2.Adjust alignment on typedef field decls/honor align attribute
3.Fix alignment for scoped enum class
4.Long long bitfield has 4bytes alignment and StorageUnitSize under 32 bit
compile mode
Differential Revision: https://reviews.llvm.org/D87029
This patch is to fix lit test case failure relate to alignment, on z/OS, maximum alignment value for 64 bit mode is 16 and also fixed clang/test/Layout/itanium-union-bitfield.cpp, attribute ((aligned(4))) is needed for bit-field member in Union for z/OS because single bit-field has one byte alignment, this will make sure size and alignment will be correct value on z/OS.
Differential Revision: https://reviews.llvm.org/D98793
See https://bugs.llvm.org/show_bug.cgi?id=42154.
GCC's __attribute__((align)) can reduce the alignment of a type when applied to
a typedef. However, functions which take a pointer or reference to the
original type are compiled assuming the original alignment. Therefore when any
such function is passed an object of the new, less-aligned type, an alignment
fault can occur. In particular, this applies to the constructor, which is
defined for the original type and called for the less-aligned object.
This change adds a warning whenever an pointer or reference to an object is
passed to a function that was defined for a more-aligned type.
The calls to ASTContext::getTypeAlignInChars seem change the order in which
record layouts are evaluated, which caused changes to the output of
-fdump-record-layouts. As such some tests needed to be updated:
* Use CHECK-LABEL rather than counting the number of "Dumping AST Record
Layout" headers.
* Check for end of line in labels, so that struct B1 doesn't match struct B
etc.
* Add --strict-whitespace, since the whitespace shows meaningful structure.
* The order in which record layouts are printed has changed in some cases.
* clang-format for regions changed
Differential Revision: https://reviews.llvm.org/D97187
Currently TypePrinter lumps anonymous classes and unnamed classes in one group "anonymous" this is not correct and can be confusing in some contexts.
Differential Revision: https://reviews.llvm.org/D96807
I missed clangd test suite and may need some time to get those working, so reverting for now.
This reverts commit ecb90b55454ee94733481247486729a504aa43a1.
Currently TypePrinter lumps anonymous classes and unnamed classes in one group "anonymous" this is not correct and can be confusing in some contexts.
Differential Revision: https://reviews.llvm.org/D96807
AIX has different layout dumping format from other itanium ABIs.
And for these two cases, use regex to match AIX format.
Differential Revision: https://reviews.llvm.org/D89064
Implement AIX default `power` alignment rule by adding `PreferredAlignment` and
`PreferredNVAlignment` in ASTRecordLayout class.
The patchh aims at returning correct value for `__alignof(x)` and `alignof(x)`
under `power` alignment rules.
Differential Revision: https://reviews.llvm.org/D79719
In particular, this affects Clang's vectors. Users encounter this issue
when a struct contains an __m128 type.
Fixes PR45420
Reviewed By: rjmccall
Differential Revision: https://reviews.llvm.org/D77754
Summary:
Add support for the C++2a [[no_unique_address]] attribute for targets using the Itanium C++ ABI.
This depends on D63371.
Reviewers: rjmccall, aaron.ballman
Subscribers: dschuff, aheejin, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D63451
llvm-svn: 363976
Handle attributes before checking the record layout (e.g. underalignment check
during `alignas` processing), as layout may be cached without taking into
account attributes that may affect it.
Differential Revision: https://reviews.llvm.org/D46439
llvm-svn: 332843
This implements the rule intended by the standard (see LWG 2358)
and the rule intended by the Itanium C++ ABI (see
https://github.com/itanium-cxx-abi/cxx-abi/pull/51), and makes
Clang match the behavior of GCC, ICC, and MSVC.
A pedantic reading of both the standard and the ABI indicate that Clang
is currently technically correct, but that's not worth much when it's
clear that the wording is wrong in both those places.
This is an ABI break for classes that derive from a class that is empty
other than one or more unnamed non-zero-length bit-fields. Such cases
are expected to be rare, but -fclang-abi-compat=6 restores the old
behavior just in case.
Differential Revision: https://reviews.llvm.org/D45174
llvm-svn: 331620
layout" rules.
The new rules say that a standard-layout struct has its first non-static
data member and all base classes at offset 0, and consider a class to
not be standard-layout if that would result in multiple subobjects of a
single type having the same address.
We track "is C++11 standard-layout class" separately from "is
standard-layout class" so that the ABIs that need this information can
still use it.
Differential Revision: https://reviews.llvm.org/D45176
llvm-svn: 329332
Printing typedefs or type aliases using clang_getTypeSpelling() is missing the
namespace they are defined in. This is in contrast to other types that always
yield the full typename including namespaces.
Patch by Michael Reiher!
Differential Revision: https://reviews.llvm.org/D29944
llvm-svn: 297465
The layout_version attribute is pretty straightforward: use the layout
rules from version XYZ of MSVC when used like
struct __declspec(layout_version(XYZ)) S {};
The empty_bases attribute is more interesting. It tries to get the C++
empty base optimization to fire more often by tweaking the MSVC ABI
rules in subtle ways:
1. Disable the leading and trailing zero-sized object flags if a class
is marked __declspec(empty_bases) and is empty.
This means that given:
struct __declspec(empty_bases) A {};
struct __declspec(empty_bases) B {};
struct C : A, B {};
'C' will have size 1 and nvsize 0 despite not being annotated
__declspec(empty_bases).
2. When laying out virtual or non-virtual bases, disable the injection
of padding between classes if the most derived class is marked
__declspec(empty_bases).
This means that given:
struct A {};
struct B {};
struct __declspec(empty_bases) C : A, B {};
'C' will have size 1 and nvsize 0.
3. When calculating the offset of a non-virtual base, choose offset zero
if the most derived class is marked __declspec(empty_bases) and the
base is empty _and_ has an nvsize of 0.
Because of the ABI rules, this does not mean that empty bases
reliably get placed at offset 0!
For example:
struct A {};
struct B {};
struct __declspec(empty_bases) C : A, B { virtual ~C(); };
'C' will be pointer sized to account for the vfptr at offset 0.
'A' and 'B' will _not_ be at offset 0 despite being empty!
Instead, they will be located right after the vfptr.
This occurs due to the interaction betweeen non-virtual base layout
and virtual function pointer injection: injection occurs after the
nv-bases and shifts them down by the size of a pointer.
llvm-svn: 270457
