Commit Graph

3412 Commits

Author SHA1 Message Date
Andrew Savonichev 3dbcea8b95 Reland [clang] Check unsupported types in expressions
This was committed as ec6c847179, but then reverted after a failure
in: https://lab.llvm.org/buildbot/#/builders/84/builds/13983

I was not able to reproduce the problem, but I added an extra check
for a NULL QualType just in case.

Original comit message:

The patch adds missing diagnostics for cases like:

  float F3 = ((__float128)F1 * (__float128)F2) / 2.0f;

Sema::checkDeviceDecl (renamed to checkTypeSupport) is changed to work
with a type without the corresponding ValueDecl. It is also refactored
so that host diagnostics for unsupported types can be added here as
well.

Differential Revision: https://reviews.llvm.org/D109315
2021-10-15 13:55:36 +03:00
Yonghong Song a162b67c98 [Clang][Attr] rename btf_tag to btf_decl_tag
Current btf_tag is applied to declaration only.
Per discussion in https://reviews.llvm.org/D111199,
we plan to introduce btf_type_tag attribute for types.
So rename btf_tag to btf_decl_tag to make it easily
differentiable from btf_type_tag.

Differential Revision: https://reviews.llvm.org/D111588
2021-10-11 22:17:17 -07:00
Kazu Hirata d409048201 [Sema] Use llvm::is_contained (NFC) 2021-10-11 11:06:44 -07:00
Sean Fertile 9b10e2b1cf [PowerPC][AIX] Warn when using pragma align(packed) on AIX.
With xlc and xlC pragma align(packed) will pack bitfields the same way
as pragma align(bit_packed). xlclang, xlclang++ and clang will
pack bitfields the same way as pragma pack(1). Issue a warning when
source code using pragma align(packed) is used to alert the user it
may not be compatable with xlc/xlC.

Differential Revision: https://reviews.llvm.org/D107506
2021-09-29 11:53:46 -04:00
Haojian Wu 3778c1cd6e [Sema] Fix a null pointer reference crash.
Differential Revision: https://reviews.llvm.org/D110315
2021-09-23 16:37:37 +02:00
Erich Keane 97b2f20a44 Change error for storage-class to mean linkage, fix lang-linkage diag
Allow multiversioning declarations to match when the actual formal
linkage matches, not just when the storage class is identical.
Additionally, change the ambiguous 'linkage' mismatch to be more
specific and say 'language linkage'.
2021-09-22 10:51:05 -07:00
Michael Benfield af99236747 Don't diagnose unused but set when the Cleanup attribute is used.
This applies to -Wunused-but-set-variable and
-Wunused-but-set-parameter.

This addresses bug 51865.

Differential Revision: https://reviews.llvm.org/D109862
2021-09-22 17:48:09 +00:00
Andrew Savonichev 6377426b4a Revert "[clang] Check unsupported types in expressions"
This reverts commit ec6c847179.

Fails on check-openmp:

/b/1/openmp-clang-x86_64-linux-debian/llvm.build/projects/openmp/runtime/test/lock/Output/omp_init_lock.c.tmp
--
Exit Code: -11
2021-09-13 15:34:21 +03:00
Andrew Savonichev ec6c847179 [clang] Check unsupported types in expressions
The patch adds missing diagnostics for cases like:

  float F3 = ((__float128)F1 * (__float128)F2) / 2.0f;

Sema::checkDeviceDecl (renamed to checkTypeSupport) is changed to work
with a type without the corresponding ValueDecl. It is also refactored
so that host diagnostics for unsupported types can be added here as
well.

Differential Revision: https://reviews.llvm.org/D109315
2021-09-13 14:59:37 +03:00
Roman Lebedev f3c2094d8c
[clang] `aligned_alloc` allocation function specifies alignment in first arg, manifest that knowledge
Mainly, if a constant value was passed as an alignment,
then we correctly annotate the alignment of the returned value
of @aligned_alloc. And if it wasn't constant,
then we also don't loose that, but emit an assumption.
2021-09-10 20:49:29 +03:00
Roman Lebedev 85ba583eba
[NFCI][clang] Move allocation alignment manifestation for malloc-like into Sema from Codegen
... so that it happens right next to `AddKnownFunctionAttributesForReplaceableGlobalAllocationFunction()`,
which is good for consistency.
2021-09-10 20:49:28 +03:00
Justas Janickas c33e296be1 [OpenCL] Disallows static kernel functions in C++ for OpenCL
It is disallowed in OpenCL C to declare static kernel functions and
C++ for OpenCL is expected to inherit such behaviour. Error is now
correctly reported in C++ for OpenCL when declaring a static kernel
function.

Differential Revision: https://reviews.llvm.org/D109150
2021-09-07 10:23:50 +01:00
Qiu Chaofan fae0dfa642 [Clang] Add __ibm128 type to represent ppc_fp128
Currently, we have no front-end type for ppc_fp128 type in IR. PowerPC
target generates ppc_fp128 type from long double now, but there's option
(-mabi=(ieee|ibm)longdouble) to control it and we're going to do
transition from IBM extended double-double ppc_fp128 to IEEE fp128 in
the future.

This patch adds type __ibm128 which always represents ppc_fp128 in IR,
as what GCC did for that type. Without this type in Clang, compilation
will fail if compiling against future version of libstdcxx (which uses
__ibm128 in headers).

Although all operations in backend for __ibm128 is done by software,
only PowerPC enables support for it.

There's something not implemented in this commit, which can be done in
future ones:

- Literal suffix for __ibm128 type. w/W is suitable as GCC documented.
- __attribute__((mode(IF))) should be for __ibm128.
- Complex __ibm128 type.

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D93377
2021-09-06 18:00:58 +08:00
Justas Janickas f9bc1b3bee [OpenCL] Defines helper function for kernel language compatible OpenCL version
This change defines a helper function getOpenCLCompatibleVersion()
inside LangOptions class. The function contains mapping between
C++ for OpenCL versions and their corresponding compatible OpenCL
versions. This mapping function should be updated each time a new
C++ for OpenCL language version is introduced. The helper function
is expected to simplify conditions on OpenCL C and C++ for OpenCL
versions inside compiler code.

Code refactoring performed.

Differential Revision: https://reviews.llvm.org/D108693
2021-08-31 10:08:38 +01:00
Nick Desaulniers 846e562dcc [Clang] add support for error+warning fn attrs
Add support for the GNU C style __attribute__((error(""))) and
__attribute__((warning(""))). These attributes are meant to be put on
declarations of functions whom should not be called.

They are frequently used to provide compile time diagnostics similar to
_Static_assert, but which may rely on non-ICE conditions (ie. relying on
compiler optimizations). This is also similar to diagnose_if function
attribute, but can diagnose after optimizations have been run.

While users may instead simply call undefined functions in such cases to
get a linkage failure from the linker, these provide a much more
ergonomic and actionable diagnostic to users and do so at compile time
rather than at link time. Users instead may be able use inline asm .err
directives.

These are used throughout the Linux kernel in its implementation of
BUILD_BUG and BUILD_BUG_ON macros. These macros generally cannot be
converted to use _Static_assert because many of the parameters are not
ICEs. The Linux kernel still needs to be modified to make use of these
when building with Clang; I have a patch that does so I will send once
this feature is landed.

To do so, we create a new IR level Function attribute, "dontcall" (both
error and warning boil down to one IR Fn Attr).  Then, similar to calls
to inline asm, we attach a !srcloc Metadata node to call sites of such
attributed callees.

The backend diagnoses these during instruction selection, while we still
know that a call is a call (vs say a JMP that's a tail call) in an arch
agnostic manner.

The frontend then reconstructs the SourceLocation from that Metadata,
and determines whether to emit an error or warning based on the callee's
attribute.

Link: https://bugs.llvm.org/show_bug.cgi?id=16428
Link: https://github.com/ClangBuiltLinux/linux/issues/1173

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D106030
2021-08-25 10:34:18 -07:00
Justas Janickas cfdfb75c1f [OpenCL] Clang diagnostics allow reporting C++ for OpenCL version.
Some Clang diagnostics could only report OpenCL C version. Because
C++ for OpenCL can be used as an alternative to OpenCL C, the text
for diagnostics should reflect that.

Desrciptions modified for these diagnostics:
`err_opencl_unknown_type_specifier`
`warn_option_invalid_ocl_version`
`err_attribute_requires_opencl_version`
`warn_opencl_attr_deprecated_ignored`
`ext_opencl_ext_vector_type_rgba_selector`

Differential Revision: https://reviews.llvm.org/D107648
2021-08-13 13:55:22 +01:00
Yonghong Song 1b194ef1ab [Clang] add btf_tag attribute
A new attribute btf_tag is added. The syntax looks like
  __attribute__((btf_tag(<string>)))

Users may tag a particular structure/member/function/func_parameter/variable
declaration with an arbitrary string and the intention is
that this string is passed to dwarf so it is available for
post-compilation analysis. The string will be also passed
to .BTF section if the target is BPF. For each permitted
declaration, multiple btf_tag's are allowed.
For detailed use cases, please see
  https://lists.llvm.org/pipermail/llvm-dev/2021-June/151009.html

In case that there exist redeclarations, the btf_tag attributes
will be accumulated along with different declarations, and the
last declaration will contain all attributes.

Differential Revision: https://reviews.llvm.org/D106614
2021-08-12 16:34:22 -07:00
Nick Desaulniers d238b60285 [Clang][DiagnosticSemaKinds] combine diagnostic texts
The diagnostic texts for warning on attributes that don't appear on the
initial declaration is generally useful.  We'd like to re-use it in
D106030, but first let's combine two that already are very similar so we
may re-use it a third time in that commit.

Also, fix a few places that were using notePreviousDefinition to point
to declarations, to instead use diag::note_previous_declaration.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D107613
2021-08-06 13:58:21 -07:00
Melanie Blower bc5b5ea037 [clang][patch][FPEnv] Make initialization of C++ globals strictfp aware
@kpn pointed out that the global variable initialization functions didn't
have the "strictfp" metadata set correctly, and @rjmccall said that there
was buggy code in SetFPModel and StartFunction, this patch is to solve
those problems. When Sema creates a FunctionDecl, it sets the
FunctionDeclBits.UsesFPIntrin to "true" if the lexical FP settings
(i.e. a combination of command line options and #pragma float_control
settings) correspond to ConstrainedFP mode. That bit is used when CodeGen
starts codegen for a llvm function, and it translates into the
"strictfp" function attribute. See bugs.llvm.org/show_bug.cgi?id=44571

Reviewed By: Aaron Ballman

Differential Revision: https://reviews.llvm.org/D102343
2021-07-29 12:02:37 -04:00
Anastasia Stulova 81600160b3 [OpenCL] Change default standard version to CL1.2
Set default version for OpenCL C to 1.2. This means that the
absence of any standard flag will be equivalent to passing
'-cl-std=CL1.2'.

Note that this patch also fixes incorrect version check for
the pointer to pointer kernel arguments diagnostic and
atomic test.

Differential Revision: https://reviews.llvm.org/D106504
2021-07-26 15:04:34 +01:00
Anton Zabaznov 05eb59e1d0 [OpenCL] Add support of __opencl_c_program_scope_global_variables feature macro
Reviewed By: Anastasia

Differential Revision: https://reviews.llvm.org/D103191
2021-07-15 17:21:19 +03:00
Aaron Ballman aefd6c615c Combine two diagnostics into one and correct grammar
The anonymous and non-anonymous bit-field diagnostics are easily
combined into one diagnostic. However, the diagnostic was missing a
"the" that is present in the almost-identically worded
warn_bitfield_width_exceeds_type_width diagnostic, hence the changes to
test cases.
2021-07-14 11:43:28 -04:00
Matheus Izvekov f2d5fce86e [clang] fixes named return of variables with dependent alignment
Named return of a variable with aligned attribute would
trip an assert in case alignment was dependent.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D105380
2021-07-07 02:54:55 +02:00
Adrian Kuegel cbb09c5b2c Revert "[clang] fixes named return of variables with dependent alignment"
This reverts commit 21106388eb.
It causes a segfault in certain cases.
2021-07-06 10:31:39 +02:00
Matheus Izvekov 21106388eb [clang] fixes named return of variables with dependent alignment
Named return of a variable with aligned attribute would
trip an assert in case alignment was dependent.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D105380
2021-07-06 02:30:44 +02:00
Simon Pilgrim 61cdaf66fe [ADT] Remove APInt/APSInt toString() std::string variants
<string> is currently the highest impact header in a clang+llvm build:

https://commondatastorage.googleapis.com/chromium-browser-clang/llvm-include-analysis.html

One of the most common places this is being included is the APInt.h header, which needs it for an old toString() implementation that returns std::string - an inefficient method compared to the SmallString versions that it actually wraps.

This patch replaces these APInt/APSInt methods with a pair of llvm::toString() helpers inside StringExtras.h, adjusts users accordingly and removes the <string> from APInt.h - I was hoping that more of these users could be converted to use the SmallString methods, but it appears that most end up creating a std::string anyhow. I avoided trying to use the raw_ostream << operators as well as I didn't want to lose having the integer radix explicit in the code.

Differential Revision: https://reviews.llvm.org/D103888
2021-06-11 13:19:15 +01:00
Nathan Sidwell 691ba0f8ac [clang][NFC] Avoid assignment in condition
Refactor to avoid assignment inside condition by using 'if
(init-decl)'.  Also remove some unnecessary braces on a separate
if-nest.

Differential Revision: https://reviews.llvm.org/D104039
2021-06-11 03:53:55 -07:00
Matheus Izvekov aef5d8fdc7 [clang] NFC: Rename rvalue to prvalue
This renames the expression value categories from rvalue to prvalue,
keeping nomenclature consistent with C++11 onwards.

C++ has the most complicated taxonomy here, and every other language
only uses a subset of it, so it's less confusing to use the C++ names
consistently, and mentally remap to the C names when working on that
context (prvalue -> rvalue, no xvalues, etc).

Renames:
* VK_RValue -> VK_PRValue
* Expr::isRValue -> Expr::isPRValue
* SK_QualificationConversionRValue -> SK_QualificationConversionPRValue
* JSON AST Dumper Expression nodes value category: "rvalue" -> "prvalue"

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D103720
2021-06-09 12:27:10 +02:00
Nathan Sidwell ddda05add5 [clang][NFC] Break out BaseUsingDecl from UsingDecl
This is a pre-patch for adding using-enum support.  It breaks out
the shadow decl handling of UsingDecl to a new intermediate base
class, BaseUsingDecl, altering the decl hierarchy to

def BaseUsing : DeclNode<Named, "", 1>;
  def Using : DeclNode<BaseUsing>;
def UsingPack : DeclNode<Named>;
def UsingShadow : DeclNode<Named>;
  def ConstructorUsingShadow : DeclNode<UsingShadow>;

Differential Revision: https://reviews.llvm.org/D101777
2021-06-07 06:29:28 -07:00
Aaron Ballman ca68f3bc48 Fix a diagnoses-valid bug with using declarations
The following was found by a customer and is accepted by the other primary
C++ compilers, but fails to compile in Clang:

namespace sss {
double foo(int, double);
template <class T>
T foo(T); // note: target of using declaration
}  // namespace sss

namespace oad {
void foo();
}

namespace oad {
using ::sss::foo;
}

namespace sss {
using oad::foo; // note: using declaration
}

namespace sss {
double foo(int, double) { return 0; }
template <class T>
T foo(T t) { // error: declaration conflicts with target of using
  return t;
}
}  // namespace sss

I believe the issue is that MergeFunctionDecl() was calling
checkUsingShadowRedecl() but only considering a FunctionDecl as a
possible shadow and not FunctionTemplateDecl. The changes in this patch
largely mirror how variable declarations were being handled by also
catching FunctionTemplateDecl.
2021-06-04 15:52:07 -04:00
Erik Pilkington 369c648399 [clang] Implement the using_if_exists attribute
This attribute applies to a using declaration, and permits importing a
declaration without knowing if that declaration exists. This is useful
for libc++ C wrapper headers that re-export declarations in std::, in
cases where the base C library doesn't provide all declarations.

This attribute was proposed in http://lists.llvm.org/pipermail/cfe-dev/2020-June/066038.html.

rdar://69313357

Differential Revision: https://reviews.llvm.org/D90188
2021-06-02 10:30:24 -04:00
Yaxun (Sam) Liu 04caa7c3e0 [CUDA][HIP] Promote const variables to constant
Recently we added diagnosing ODR-use of host variables
in device functions, which includes ODR-use of const
host variables since they are not really emitted on
device side. This caused regressions since we used
to allow ODR-use of const host variables in device
functions.

This patch allows ODR-use of const variables in device
functions if the const variables can be statically initialized
and have an empty dtor. Such variables are marked with
implicit constant attrs and emitted on device side. This is
in line with what clang does for constexpr variables.

Reviewed by: Artem Belevich

Differential Revision: https://reviews.llvm.org/D103108
2021-06-01 21:28:41 -04:00
Michael Benfield cf49cae278 [Clang] -Wunused-but-set-parameter and -Wunused-but-set-variable
These are intended to mimic warnings available in gcc.

Differential Revision: https://reviews.llvm.org/D100581
2021-06-01 15:38:48 -07:00
Abbas Sabra 116179c2ee Re-commit [clang] Add support for the "abstract" contextual keyword of MSVC
https://docs.microsoft.com/en-us/cpp/extensions/abstract-cpp-component-extensions?view=msvc-160
Note: like the already supported "sealed" keyword, the "abstract"
keyword is supported by MSVC by default.

This re-commits 818338add7 with added
initialization of Parser::Ident_abstract.

Differential revision: https://reviews.llvm.org/D102517
2021-05-31 18:45:26 +02:00
Mikhail Goncharov c36ff6424f Revert "[clang] Add support for the "abstract" contextual keyword of MSVC"
This reverts commit 818338add7.

Tests fail under sanitizer: https://lab.llvm.org/buildbot/#/builders/5/builds/8150
2021-05-31 15:34:20 +02:00
Abbas Sabra 818338add7 [clang] Add support for the "abstract" contextual keyword of MSVC
https://docs.microsoft.com/en-us/cpp/extensions/abstract-cpp-component-extensions?view=msvc-160
Note: like the already supported "sealed" keyword, the "abstract"
keyword is supported by MSVC by default.

Differential revision: https://reviews.llvm.org/D102517
2021-05-31 10:44:53 +02:00
Momchil Velikov 21aa107eb7 Reland "Do not create LLVM IR `constant`s for objects with dynamic initialisation"
This relands commit 13dd65b3a1.

The original commit contained a test, which failed when compiled
for a MACH-O target.

This patch changes the test to run for x86_64-linux instead of
`%itanium_abi_triple`, to avoid having invalid syntax for MACH-O
sections. The patch itself does not care about section attribute
syntax and a x86 backend does not even need to be included in the
build.

Differential Revision: https://reviews.llvm.org/D102693
2021-05-25 15:54:40 +01:00
Nico Weber d881319cc5 Revert "Do not create LLVM IR `constant`s for objects with dynamic initialisation"
This reverts commit 13dd65b3a1.
Breaks check-clang on macOS, see https://reviews.llvm.org/D102693
2021-05-24 21:22:07 -04:00
Momchil Velikov 13dd65b3a1 Do not create LLVM IR `constant`s for objects with dynamic initialisation
When a const-qualified object has a section attribute, that
section is set to read-only and clang outputs a LLVM IR constant
for that object. This is incorrect for dynamically initialised
objects.

For example:

    int init() { return 15; }

    __attribute__((section("SA")))
    const int a = init();

a is allocated to a read-only section and is left
unintialised (zero-initialised).

This patch adds checks if an initialiser is a constant expression
and allocates objects to sections as follows:

* const-qualified objects
  - no initialiser or constant initialiser: .rodata
  - dynamic initializer: .bss
* non const-qualified objects
  - no initialiser or dynamic initialiser: .bss
  - constant initialiser: .data

(".rodata", ".data", and ".bss" names used just for explanatory
purpose)

Differential Revision: https://reviews.llvm.org/D102693
2021-05-24 22:04:15 +01:00
Anastasia Stulova 237c6924bd [OpenCL] Add clang extension for bit-fields.
Allow use of bit-fields as a clang extension
in OpenCL. The extension can be enabled using
pragma directives.

This fixes PR45339!

Differential Revision: https://reviews.llvm.org/D101843
2021-05-24 12:42:17 +01:00
Wei Wang e6b8320c0a [clang][AST] Improve AST Reader/Writer memory footprint
Reduce memory footprint of AST Reader/Writer:
1. Adjust internal data containers' element type.
2. Switch to set for deduplication of deferred diags.

Differential Revision: https://reviews.llvm.org/D101793
2021-05-20 15:34:29 -07:00
Alex Lorenz 50be48b0f3 [clang][ObjC] Allow different availability annotation on a method
when implementing an optional protocol requirement

When an Objective-C method implements an optional protocol requirement,
allow the method to use a newer introduced or older obsoleted
availability version than what's specified on the method in the protocol
itself. This allows SDK adopters to adopt an optional method from a
protocol later than when the method is introduced in the protocol. The users
that call an optional method on an object that conforms to this protocol
are supposed to check whether the object implements the method or not,
so a lack of appropriate `if (@available)` check for a new OS version
is not a cause of concern as there's already another runtime check that's required.

Differential Revision: https://reviews.llvm.org/D102459
2021-05-19 12:13:57 -07:00
Ole Strohm 642d2f000b [OpenCL] Fix initialization of __constant constructors without arguments
This fixes the initialization of objects in the __constant
address space that occurs when declaring the object.

Fixes part of PR42566

Reviewed By: Anastasia

Differential Revision: https://reviews.llvm.org/D102248
2021-05-18 10:59:53 +01:00
Arthur Eubanks 3a0b6dc3e8 Revert "[Clang] -Wunused-but-set-parameter and -Wunused-but-set-variable"
This reverts commit 14dfb3831c.

More false positives, see D100581.
2021-05-17 12:16:10 -07:00
Michael Benfield 14dfb3831c [Clang] -Wunused-but-set-parameter and -Wunused-but-set-variable
These are intended to mimic warnings available in gcc.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D100581
2021-05-17 11:02:26 -07:00
Anastasia Stulova 3549466ac0 [OpenCL] Drop pragma handling for extension types/decls.
Drop non-conformant extension pragma implementation as
it does not properly disable anything and therefore
enabling non-disabled logic has no meaning.

This simplifies clang code and user interface to the extension
functionality. With this patch extension pragma 'begin'/'end'
and 'enable'/'disable' are only accepted for backward
compatibility and no longer have any default behavior.

Differential Revision: https://reviews.llvm.org/D101043
2021-05-17 12:09:43 +01:00
Johannes Doerfert df729e2b82 [OpenMP] Overhaul `declare target` handling
This patch fixes various issues with our prior `declare target` handling
and extends it to support `omp begin declare target` as well.

This started with PR49649 in mind, trying to provide a way for users to
avoid the "ref" global use introduced for globals with internal linkage.
From there it went down the rabbit hole, e.g., all variables, even
`nohost` ones, were emitted into the device code so it was impossible to
determine if "ref" was needed late in the game (based on the name only).
To make it really useful, `begin declare target` was needed as it can
carry the `device_type`. Not emitting variables eagerly had a ripple
effect. Finally, the precedence of the (explicit) declare target list
items needed to be taken into account, that meant we cannot just look
for any declare target attribute to make a decision. This caused the
handling of functions to require fixup as well.

I tried to clean up things while I was at it, e.g., we should not "parse
declarations and defintions" as part of OpenMP parsing, this will always
break at some point. Instead, we keep track what region we are in and
act on definitions and declarations instead, this is what we do for
declare variant and other begin/end directives already.

Highlights:
  - new diagnosis for restrictions specificed in the standard,
  - delayed emission of globals not mentioned in an explicit
    list of a declare target,
  - omission of `nohost` globals on the host and `host` globals on the
    device,
  - no explicit parsing of declarations in-between `omp [begin] declare
    variant` and the corresponding end anymore, regular parsing instead,
  - precedence for explicit mentions in `declare target` lists over
    implicit mentions in the declaration-definition-seq, and
  - `omp allocate` declarations will now replace an earlier emitted
    global, if necessary.

---

Notes:

The patch is larger than I hoped but it turns out that most changes do
on their own lead to "inconsistent states", which seem less desirable
overall.

After working through this I feel the standard should remove the
explicit declare target forms as the delayed emission is horrible.
That said, while we delay things anyway, it seems to me we check too
often for the current status even though that is often not sufficient to
act upon. There seems to be a lot of duplication that can probably be
trimmed down. Eagerly emitting some things seems pretty weak as an
argument to keep so much logic around.

---

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D101030
2021-05-06 02:10:41 -05:00
Anastasia Stulova e994e74bca [OpenCL] Add clang extension for non-portable kernel parameters.
Added __cl_clang_non_portable_kernel_param_types extension that
allows using non-portable types as kernel parameters. This allows
bypassing the portability guarantees from the restrictions specified
in C++ for OpenCL v1.0 s2.4.

Currently this only disables the restrictions related to the data
layout. The programmer should ensure the compiler generates the same
layout for host and device or otherwise the argument should only be
accessed on the device side. This extension could be extended to other
case (e.g. permitting size_t) if desired in the future.

Patch by olestrohm (Ole Strohm)!

https://reviews.llvm.org/D101168
2021-05-05 14:58:23 +01:00
serge-sans-paille b83b23275b Introduce -Wreserved-identifier
Warn when a declaration uses an identifier that doesn't obey the reserved
identifier rule from C and/or C++.

Differential Revision: https://reviews.llvm.org/D93095
2021-05-04 11:19:01 +02:00
Arthur Eubanks 6d8d133862 Revert "[Clang] -Wunused-but-set-parameter and -Wunused-but-set-variable"
This reverts commit 9b0501abc7.

False positives reported in D100581.
2021-04-28 12:47:18 -07:00
Anastasia Stulova 6a92c19f3b [C++4OpenCL] Add diagnostics for OpenCL types in templates.
Refactored diagnostics for OpenCL types to allow their
reuse for templates.

Patch by olestrohm (Ole Strohm)!

Differential Revision: https://reviews.llvm.org/D100860
2021-04-27 13:04:25 +01:00
Yonghong Song a2a3ca8d97 BPF: emit debuginfo for Function of DeclRefExpr if requested
Commit e3d8ee35e4 ("reland "[DebugInfo] Support to emit debugInfo
for extern variables"") added support to emit debugInfo for
extern variables if requested by the target. Currently, only
BPF target enables this feature by default.

As BPF ecosystem grows, callback function started to get
support, e.g., recently bpf_for_each_map_elem() is introduced
(https://lwn.net/Articles/846504/) with a callback function as an
argument. In the future we may have something like below as
a demonstration of use case :
    extern int do_work(int);
    long bpf_helper(void *callback_fn, void *callback_ctx, ...);
    long prog_main() {
        struct { ... } ctx = { ... };
        return bpf_helper(&do_work, &ctx, ...);
    }
Basically bpf helper may have a callback function and the
callback function is defined in another file or in the kernel.
In this case, we would like to know the debuginfo types for
do_work(), so the verifier can proper verify the safety of
bpf_helper() call.

For the following example,
    extern int do_work(int);
    long bpf_helper(void *callback_fn);
    long prog() {
        return bpf_helper(&do_work);
    }

Currently, there is no debuginfo generated for extern function do_work().
In the IR, we have,
    ...
    define dso_local i64 @prog() local_unnamed_addr #0 !dbg !7 {
    entry:
      %call = tail call i64 @bpf_helper(i8* bitcast (i32 (i32)* @do_work to i8*)) #2, !dbg !11
      ret i64 %call, !dbg !12
    }
    ...
    declare dso_local i32 @do_work(i32) #1
    ...

This patch added support for the above callback function use case, and
the generated IR looks like below:
    ...
    declare !dbg !17 dso_local i32 @do_work(i32) #1
    ...
    !17 = !DISubprogram(name: "do_work", scope: !1, file: !1, line: 1, type: !18, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized, retainedNodes: !2)
    !18 = !DISubroutineType(types: !19)
    !19 = !{!20, !20}
    !20 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)

The TargetInfo.allowDebugInfoForExternalVar is renamed to
TargetInfo.allowDebugInfoForExternalRef as now it guards
both extern variable and extern function debuginfo generation.

Differential Revision: https://reviews.llvm.org/D100567
2021-04-26 16:53:25 -07:00
Michael Benfield 9b0501abc7 [Clang] -Wunused-but-set-parameter and -Wunused-but-set-variable
These are intended to mimic warnings available in gcc.

-Wunused-but-set-variable is triggered in the case of a variable which
appears on the LHS of an assignment but not otherwise used.

For instance:

  void f() {
    int x;
    x = 0;
  }

-Wunused-but-set-parameter works similarly, but for function parameters
instead of variables.

In C++, they are triggered only for scalar types; otherwise, they are
triggered for all types. This is gcc's behavior.

-Wunused-but-set-parameter is controlled by -Wextra, while
-Wunused-but-set-variable is controlled by -Wunused. This is slightly
different from gcc's behavior, but seems most consistent with clang's
behavior for -Wunused-parameter and -Wunused-variable.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D100581
2021-04-26 15:09:03 -07:00
Johannes Doerfert cbe8b57a67 [Clang] Allow the combination of loader_uninitialized and address spaces
When an object is allocated in a non-default address space we do not
need to check for a constructor if it is not initialized and has a
trivial constructor (which we won't call then).

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D100929
2021-04-23 11:21:52 -05:00
Anastasia Stulova 362958ac73 [C++4OpenCL] Add extra diagnostics for kernel argument types
Add restrictions on type layout (PR48099):
- Types passed by pointer or reference must be standard layout types.
- Types passed by value must be POD types.

Patch by olestrohm (Ole Strohm)!

Differential Revision: https://reviews.llvm.org/D100471
2021-04-22 15:28:04 +01:00
Eli Friedman dc1ab590a0 [Sema] Fold VLA types in compound literals to constant arrays.
Similar to variables with an initializer, this is never valid in
standard C, so we can safely constant-fold as an extension.  I ran into
this construct in a couple proprietary codebases.

While I'm here, drive-by fix for 090dd647: we should only fold variables
with VLA types, not arbitrary variably modified types.

Differential Revision: https://reviews.llvm.org/D98363
2021-04-14 17:09:59 -07:00
Erich Keane 92aba5ae49 CPUDispatch- allow out of line member definitions
ICC permits this, and after some extensive testing it looks like we can
support this with very little trouble.  We intentionally don't choose to
do this with attribute-target (despite it likely working as well!)
  because GCC does not support that, and introducing said
  incompatibility doesn't seem worth it.
2021-04-14 06:19:49 -07:00
Aaron Ballman c058a71227 Correct the tablegen for checking mutually exclusive stmt attrs
The previous implementation was insufficient for checking statement
attribute mutual exclusion because attributed statements do not collect
their attributes one-at-a-time in the same way that declarations do. So
the design that was attempting to check for mutual exclusion as each
attribute was processed would not ever catch a mutual exclusion in a
statement. This was missed due to insufficient test coverage, which has
now been added for the [[likely]] and [[unlikely]] attributes.

The new approach is to check all of attributes that are to be applied
to the attributed statement in a group. This required generating
another DiagnoseMutualExclusions() function into AttrParsedAttrImpl.inc.
2021-04-13 15:20:30 -04:00
Sander de Smalen 6bf806b3e2 [AArch64] ACLE: Fix issue for mismatching enum types with builtins.
This patch fixes an issue with the SVE prefetch and qinc/qdec intrinsics
that take an `enum` argument, but where the builtin prototype encodes
these as `int`. Some code in SemaDecl found the mismatch and chose
to forget about the builtin altogether, which meant that any future
code using that builtin would fail. The code that forgets about the
builtin was actually obsolete after D77491 and should have been removed.
This patch now removes that code.

This patch also fixes another issue with the SVE prefetch intrinsic
when built with C++, where the builtin didn't accept the correct
pointer type, which should be `const void *`.

Reviewed By: tambre

Differential Revision: https://reviews.llvm.org/D100046
2021-04-12 11:16:28 +01:00
Alex Richardson dc4abca766 Handle alloc_size attribute on function pointers
I have been trying to statically find and analyze all calls to heap
allocation functions to determine how many of them use sizes known at
compile time vs only at runtime. While doing so I saw that quite a few
projects use replaceable function pointers for heap allocation and noticed
that clang was not able to annotate functions pointers with alloc_size.
I have changed the Sema checks to allow alloc_size on all function pointers
and typedefs for function pointers now and added checks that these
attributes are propagated to the LLVM IR correctly.

With this patch we can also compute __builtin_object_size() for calls to
allocation function pointers with the alloc_size attribute.

Reviewed By: aaron.ballman, erik.pilkington
Differential Revision: https://reviews.llvm.org/D55212
2021-04-09 18:49:38 +01:00
Simon Pilgrim 2901dc7575 Don't directly dereference getAs<> casts to avoid potential null dereferences. NFCI.
Replace with castAs<> which asserts the cast is valid.

Fixes a number of static analyzer warnings.
2021-04-06 12:24:19 +01:00
Aaron Ballman 4be8a26951 Use tablegen to diagnose mutually exclusive attributes
Currently, when one or more attributes are mutually exclusive, the
developer adding the attribute has to manually emit diagnostics. In
practice, this is highly error prone, especially for declaration
attributes, because such checking is not trivial. Redeclarations
require you to write a "merge" function to diagnose mutually exclusive
attributes and most attributes get this wrong.

This patch introduces a table-generated way to specify that a group of
two or more attributes are mutually exclusive:

def : MutualExclusions<[Attr1, Attr2, Attr3]>;

This works for both statement and declaration attributes (but not type
attributes) and the checking is done either from the common attribute
diagnostic checking code or from within mergeDeclAttribute() when
merging redeclarations.
2021-04-02 16:34:42 -04:00
Ta-Wei Tu 99fd066227 [clang][Sema] Don't try to initialize implicit variable of invalid anonymous union/struct
This fixes https://bugs.llvm.org/show_bug.cgi?id=49534, where the call to the constructor
of the anonymous union is checked and triggers assertion failure when trying to retrieve
the alignment of the `this` argument (which is a union with virtual function).

The extra check for alignment was introduced in D97187.

Reviewed By: tmatheson

Differential Revision: https://reviews.llvm.org/D98548
2021-03-31 09:05:45 +08:00
Elizabeth Andrews d8b8f544d9 [Reland] "Do not apply calling conventions to MSVC entry points"
This patch is a second attempt at fixing a link error for MSVC
entry points when calling conventions are specified using a flag.

Calling conventions specified using flags should not be applied to MSVC
entry points. The default calling convention is set in this case. The
default calling convention for MSVC entry points main and wmain is cdecl.
For WinMain, wWinMain and DllMain, the default calling convention is
stdcall on 32 bit Windows.

Explicitly specified calling conventions are applied to MSVC entry points.

For MinGW, the default calling convention for all MSVC entry points is
cdecl.

First attempt: 4cff1b40da
Revert of first attempt: bebfc3b92d

Differential Revision: https://reviews.llvm.org/D97941
2021-03-18 04:26:47 -07:00
Anton Zabaznov 840643bbe1 [OpenCL] Refactor diagnostic for OpenCL extension/feature
There is no need to check for enabled pragma for core or optional core features,
thus this check is removed

Reviewed By: Anastasia

Differential Revision: https://reviews.llvm.org/D97058
2021-03-12 11:43:53 +03:00
PremAnand Rao c2de5aff1a [OpenMP] Handle non-function context before checking for diagnostic
emission

Ensure that we are in a function declaration context before checking
the diagnostic emission status, to avoid dereferencing a NULL function
declaration.

Differential Revision: https://reviews.llvm.org/D97573
2021-03-05 12:37:49 -08:00
Fangrui Song 8afdacba9d Add GNU attribute 'retain'
For ELF targets, GCC 11 will set SHF_GNU_RETAIN on the section of a
`__attribute__((retain))` function/variable to prevent linker garbage
collection. (See AttrDocs.td for the linker support).

This patch adds `retain` functions/variables to the `llvm.used` list, which has
the desired linker GC semantics. Note: `retain` does not imply `used`,
so an unused function/variable can be dropped by Sema.

Before 'retain' was introduced, previous ELF solutions require inline asm or
linker tricks, e.g.  `asm volatile(".reloc 0, R_X86_64_NONE, target");`
(architecture dependent) or define a non-local symbol in the section and use
`ld -u`. There was no elegant source-level solution.

With D97448, `__attribute__((retain))` will set `SHF_GNU_RETAIN` on ELF targets.

Differential Revision: https://reviews.llvm.org/D97447
2021-02-26 16:37:50 -08:00
Zequan Wu 4500f0a732 [Clang][Attributes] Allow not_tail_called attribute to be applied to virtual function.
It would be beneficial to allow not_tail_called attribute to be applied to
virtual functions. I don't see any drawback of allowing this.

Differential Revision: https://reviews.llvm.org/D96832
2021-02-25 14:58:18 -08:00
David Crook 039f79c78c [SEMA] Added warn_decl_shadow support for structured bindings
https://bugs.llvm.org/show_bug.cgi?id=40858

CheckShadow is now called for each binding in the structured binding to make sure it does not shadow any other variable in scope. This does use a custom implementation of getShadowedDeclaration though because a BindingDecl is not a VarDecl

Added a few unit tests for this. In theory though all the other shadow unit tests should be duplicated for the structured binding variables too but whether it is probably not worth it as they use common code. The MyTuple and std interface code has been copied from live-bindings-test.cpp

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D96147
2021-02-23 13:37:05 -08:00
Fangrui Song bccdf6b232 Improve diagnostic for ignored GNU 'used' attribute
Differential Revision: https://reviews.llvm.org/D97161
2021-02-22 09:18:13 -08:00
Daan De Meyer 7dd42ecfa2 clang: Exclude efi_main from -Wmissing-prototypes
When compiling UEFI applications, the main function is named
efi_main() instead of main(). Let's exclude efi_main() from
-Wmissing-prototypes as well to avoid warnings when working
on UEFI applications.

Differential Revision: https://reviews.llvm.org/D95746
2021-02-20 20:00:50 +00:00
Johannes Doerfert 1dd66e6111 [OpenMP] Delay more diagnostics of potentially non-emitted code
Even code in target and declare target regions might not be emitted.
With this patch we delay more diagnostics and use laziness and linkage
to determine if a function is emitted (for the device). Note that we
still eagerly emit diagnostics for target regions, unfortunately, see
the TODO for the reason.

This hopefully fixes PR48933.

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D95928
2021-02-15 13:17:05 -06:00
Johannes Doerfert f9286b434b [OpenMP] Attribute target diagnostics properly
Type errors in function declarations were not (always) diagnosed prior
to this patch. Furthermore, certain remarks did not get associated
properly which caused them to be emitted multiple times.

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D95912
2021-02-15 13:16:55 -06:00
Anastasia Stulova 5bbf39704c [OpenCL] Add diagnostics for references to functions
Restrict use of references to functions as they can
result in non-conforming behavior.

Tags: #clang

Differential Revision: https://reviews.llvm.org/D95442
2021-02-02 15:07:40 +00:00
Mikhail Maltsev 30d9ca1bd9 [clang][AST] Encapsulate DeclarationNameLoc, NFCI
This change makes `DeclarationNameLoc` a proper class and refactors its
users to use getter methods instead of accessing the members directly.
The change also makes `DeclarationNameLoc` immutable (i.e., it cannot
be modified once constructed).

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D94596
2021-01-27 11:21:01 +00:00
Richard Smith e92be7cd9f PR47682: Merge the DeclContext of a merged FunctionDecl before we inherit
default arguments.

When a function is declared with a qualified name, its eventual semantic
DeclContext may differ from the scope specified by the qualifier if it
redeclares a function in an inline namespace. In this case, we need to
update the DeclContext to be that of the previous declaration, and we
need to do so before we decide whether to inherit default arguments from
that previous declaration, because we only inherit default arguments
from declarations in the same scope.
2021-01-22 15:46:41 -08:00
Mikhail Maltsev 17f8c458de [clang] Use SourceLocations in unions [NFCI]
Currently, there are many instances where `SourceLocation` objects are
converted to raw representation to be stored in structs that are
used as fields of tagged unions.

This is done to make the corresponding structs trivial.
Triviality allows avoiding undefined behavior when implicitly changing
the active member of the union.

However, in most cases, we can explicitly construct an active member
using placement new. This patch adds the required active member
selections and replaces `SourceLocation`-s represented as
`unsigned int` with proper `SourceLocation`-s.

One notable exception is `DeclarationNameLoc`: the objects of this class
are often not properly initialized (so the code currently relies on
its default constructor which uses memset). This class will be fixed
in a separate patch.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D94237
2021-01-14 10:56:53 +00:00
Sean Dooher 35c9baa11e [attributes] Add a facility for enforcing a Trusted Computing Base.
Introduce a function attribute 'enforce_tcb' that prevents the function
from calling other functions without the same attribute. This allows
isolating code that's considered to be somehow privileged so that it could not
use its privileges to exhibit arbitrary behavior.

Introduce an on-by-default warning '-Wtcb-enforcement' that warns
about violations of the above rule.

Introduce a function attribute 'enforce_tcb_leaf' that suppresses
the new warning within the function it is attached to. Such leaf functions
may implement common functionality between the trusted and the untrusted code
but they require extra careful audit with respect to their capabilities.

Fixes after a revert in 419ef38a50293c58078f830517f5e305068dbee6:
Fix a test.
Add workaround for GCC bug (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67274).
Attribute the patch appropriately!

Differential Revision: https://reviews.llvm.org/D91898
2021-01-11 10:20:51 -08:00
Nico Weber 419ef38a50 Revert "[attributes] Add a facility for enforcing a Trusted Computing Base."
This reverts commit c163aae45e.
Doesn't compile on some bots
(http://lab.llvm.org:8011/#/builders/98/builds/3387/steps/9/logs/stdio),
breaks tests on bots where it does compile
(http://45.33.8.238/linux/36843/step_7.txt).
2021-01-11 09:51:06 -05:00
Artem Dergachev c163aae45e [attributes] Add a facility for enforcing a Trusted Computing Base.
Introduce a function attribute 'enforce_tcb' that prevents the function
from calling other functions without the same attribute. This allows
isolating code that's considered to be somehow privileged so that it could not
use its privileges to exhibit arbitrary behavior.

Introduce an on-by-default warning '-Wtcb-enforcement' that warns
about violations of the above rule.

Introduce a function attribute 'enforce_tcb_leaf' that suppresses
the new warning within the function it is attached to. Such leaf functions
may implement common functionality between the trusted and the untrusted code
but they require extra careful audit with respect to their capabilities.

Differential Revision: https://reviews.llvm.org/D91898
2021-01-11 06:39:42 -08:00
Mikhail Maltsev 9f76788b09 [clang][Sema] Compare SourceLocations directly [NFCI]
The ordered comparison operators are defined for the SourceLocation
class, so SourceLocation objects can be compared directly. There is no
need to extract the internal representation for comparison.

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D94231
2021-01-09 14:13:18 +00:00
Anastasia Stulova 4fde2b6a0c [OpenCL] Add clang extension for function pointers.
The new clang internal extension '__cl_clang_function_pointers'
allows use of function pointers and other features that have
the same functionality:
- Use of member function pointers;
- Unrestricted use of references to functions;
- Virtual member functions.

This not a vendor extension and therefore it doesn't require any
special target support. Exposing this functionality fully
will require vendor or Khronos extension.

Tags: #clang

Differential Revision: https://reviews.llvm.org/D94021
2021-01-06 20:39:57 +00:00
Anastasia Stulova 6f770292a0 [OpenCL] Restrict pointer to member functions.
Pointers to member functions are a special case
of function pointers and therefore have to be
disallowed.

Tags: #clang

Differential Revision: https://reviews.llvm.org/D93958
2021-01-05 13:32:18 +00:00
Thorsten Schütt 2fd11e0b1e Revert "[NFC, Refactor] Modernize StorageClass from Specifiers.h to a scoped enum (II)"
This reverts commit efc82c4ad2.
2021-01-04 23:17:45 +01:00
Thorsten Schütt efc82c4ad2 [NFC, Refactor] Modernize StorageClass from Specifiers.h to a scoped enum (II)
Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D93765
2021-01-04 22:58:26 +01:00
Richard Smith 4b388859f5 Ensure that we transform types into the current instantiation even if
they're only instantiation-dependent.
2020-12-17 23:23:05 -08:00
Richard Smith 71886c56f3 Where possible, don't try to ask whether a template argument is
dependent until it's been converted to match its parameter.

The type of a non-type template parameter can in general affect whether
the template argument is dependent.

Note that this is not always possible. For template arguments that name
static local variables in templates, the type of the template parameter
affects whether the argument is dependent, so the query is imprecise
until we know the parameter type. For example, in:

template<typename T> void f() {
  static const int n = 5;
  typename T::template X<n> x;
}

... we don't know whether 'n' is dependent until we know whether the
corresponding template parameter is of type 'int' or 'const int&'.
2020-12-17 23:23:05 -08:00
Johannes Doerfert 2e6e4e6aee [OpenMP] Add initial support for `omp [begin/end] assumes`
The `assumes` directive is an OpenMP 5.1 feature that allows the user to
provide assumptions to the optimizer. Assumptions can refer to
directives (`absent` and `contains` clauses), expressions (`holds`
clause), or generic properties (`no_openmp_routines`, `ext_ABCD`, ...).

The `assumes` spelling is used for assumptions in the global scope while
`assume` is used for executable contexts with an associated structured
block.

This patch only implements the global spellings. While clauses with
arguments are "accepted" by the parser, they will simply be ignored for
now. The implementation lowers the assumptions directly to the
`AssumptionAttr`.

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D91980
2020-12-16 20:02:49 -06:00
Erik Pilkington 95b2dab199 [Sema] Fix a miscompile by retaining array qualifiers when folding VLAs to constant arrays
rdar://72243125

Differential revision: https://reviews.llvm.org/D93247
2020-12-16 10:01:24 -05:00
Johannes Doerfert 1efd7a73ac Revert "[OpenMP] Add initial support for `omp [begin/end] assumes`"
There is a build error with gcc-5 [0], investigating now.

[0] https://reviews.llvm.org/D91980#2456526

This reverts commit a5a14cbe7f.
2020-12-15 18:03:10 -06:00
Johannes Doerfert a5a14cbe7f [OpenMP] Add initial support for `omp [begin/end] assumes`
The `assumes` directive is an OpenMP 5.1 feature that allows the user to
provide assumptions to the optimizer. Assumptions can refer to
directives (`absent` and `contains` clauses), expressions (`holds`
clause), or generic properties (`no_openmp_routines`, `ext_ABCD`, ...).

The `assumes` spelling is used for assumptions in the global scope while
`assume` is used for executable contexts with an associated structured
block.

This patch only implements the global spellings. While clauses with
arguments are "accepted" by the parser, they will simply be ignored for
now. The implementation lowers the assumptions directly to the
`AssumptionAttr`.

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D91980
2020-12-15 16:51:34 -06:00
shafik 6333871f85 Add diagnostic for for-range-declaration being specificed with thread_local
Currently we have a diagnostic that catches the other storage class specifies for the range based for loop declaration but we miss the thread_local case. This changes adds a diagnostic for that case as well.

Differential Revision: https://reviews.llvm.org/D92671
2020-12-04 15:06:35 -08:00
Erik Pilkington 090dd647d9 [Sema] Fold VLAs to constant arrays in a few more contexts
552c6c2 removed support for promoting VLAs to constant arrays when the bounds
isn't an ICE, since this can result in miscompiling a conforming program that
assumes that the array is a VLA. Promoting VLAs for fields is still supported,
since clang doesn't support VLAs in fields, so no conforming program could have
a field VLA.

This change is really disruptive, so this commit carves out two more cases
where we promote VLAs which can't miscompile a conforming program:

 - When the VLA appears in an ivar -- this seems like a corollary to the field thing
 - When the VLA has an initializer -- VLAs can't have an initializer

Differential revision: https://reviews.llvm.org/D90871
2020-12-04 10:03:23 -05:00
Richard Smith c4fb7720ce PR48339: Improve diagnostics for invalid dependent unqualified function calls.
Fix bogus diagnostics that would get confused and think a "no viable
fuctions" case was an "undeclared identifiers" case, resulting in an
incorrect diagnostic preceding the correct one. Use overload resolution
to determine which function we should select when we can find call
candidates from a dependent base class. Make the diagnostics for a call
that could call a function from a dependent base class more specific,
and use a different diagnostic message for the case where the call
target is instead declared later in the same class. Plus some minor
diagnostic wording improvements.
2020-12-02 17:54:55 -08:00
Richard Smith 1f40d60a3b Remove CXXBasePaths::found_decls and simplify and modernize its only
caller.

This function did not satisfy its documented contract: it only
considered the first lookup result on each base path, not all lookup
results. It also performed unnecessary memory allocations.

This change results in a minor change to our representation: we now
include overridden methods that are found by any derived-to-base path
(not involving another override) in the list of overridden methods for a
function, rather than filtering out functions from bases that are both
direct virtual bases and indirect virtual bases for which the indirect
virtual base path contains another override for the function. (That
filtering rule is part of the class-scope name lookup rules, and doesn't
really have much to do with enumerating overridden methods.) The users
of the list of overridden methods do not appear to rely on this
filtering having happened, and it's simpler to not do it.
2020-12-01 16:35:03 -08:00
Sven van Haastregt 523775f967 [OpenCL] Allow pointer-to-pointer kernel args beyond CL 1.2
The restriction on pointer-to-pointer kernel arguments has been
relaxed in OpenCL 2.0.  Apply the same address space restrictions for
pointer argument types to the inner pointer types.

Differential Revision: https://reviews.llvm.org/D92091
2020-12-01 11:33:10 +00:00
Ben Dunbobbin d5aaf60214 [windows-itanium] handle dllimport/export code paths separately and share with PS4
Similar to Windows Itanium, PS4 is also an Itanium C++ ABI variant
which shares the goal of semantic compatibility with Microsoft C++
code that uses dllimport/export.

This change introduces a new function to determine from the triple
if an environment aims for compatibility with MS C++ code w.r.t to
these attributes and guards the relevant code paths using that
function.

Differential Revision: https://reviews.llvm.org/D90299
2020-11-30 14:36:39 +00:00
Faisal Vali 9930d4dff3 [NFC, Refactor] Modernize enum FunctionDefinitionKind (DeclSpech.h) into a scoped enum
Reviewed by aaron.ballman, rsmith, wchilders
Highlights of review:
- avoid specifying an underlying type (unless such an enum is stored (or part of an abi?))
- avoid using enums as bit-fields, preferring unsigned bit-fields that we static_cast enumerators to. (MS's abi laysout enum bit-fields differently).
- clang-format, clang-format, clang-format.

https://reviews.llvm.org/D91035

Thank you!
2020-11-21 09:49:52 -06:00
Richard Smith 8e923ec2a8 Fix assertions and bad warnings on extremely wide bit-fields.
We used to produce a bogus warning if the width couldn't be represented
in 32 bits, and assert if it couldn't be represented in 64 bits.
2020-11-17 14:36:51 -08:00
Thorsten 41b65f166b Convert ConstexprKind from Specifiers.h to a scoped enum; NFC 2020-11-16 14:10:19 -05:00
Alexey Bataev 07b568a9c8 [OPENMP]Fix PR47790: segfault in frontend while parsing Objective-C with OpenMP.
Need to check if the sema is actually finishing a function decl.

Differential Revision: https://reviews.llvm.org/D91376
2020-11-12 13:26:11 -08:00
Hans Wennborg a088766508 [dllexport] Instantiate default ctor default args for explicit specializations (PR45811)
For dllexported default constructors with default arguments, we export
default constructor closures which pass in the default args. (See D8331
for a good explanation.)

For templates, that means those default args must be instantiated even
if the function isn't called. That is done by the
InstantiateDefaultCtorDefaultArgs() function, but it wasn't done for
explicit specializations, causing asserts (see bug).

Differential revision: https://reviews.llvm.org/D91089
2020-11-12 13:29:34 +01:00
Faisal Vali e4d27932a5 [NFC, Refactor] Rename the (scoped) enum DeclaratorContext's enumerators to remove duplication
Since these are scoped enumerators, they have to be prefixed by DeclaratorContext, so lets remove Context from the name, and return some characters to the multiverse.

Patch was reviewed here: https://reviews.llvm.org/D91011

Thank you to aaron, bruno, wyatt and barry for indulging me.
2020-11-10 23:40:12 -06:00
Baptiste Saleil f976ba6139 [PowerPC] Add Sema checks for MMA types
The use of the new types introduced for PowerPC MMA instructions needs to be restricted.
We add a PowerPC function checking that the given type is valid in a context in which we don't allow MMA types.
This function is called from various places in Sema where we want to prevent the use of these types.

Differential Revision: https://reviews.llvm.org/D82035
2020-11-04 17:01:47 -06:00
Artem Belevich be86b6773b [CUDA] Allow local static variables with target attributes.
While CUDA documentation claims that such variables are not allowed[1], NVCC has
been accepting them since CUDA-10.0[2] and some headers in CUDA-11 rely on this
working.

1. https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#static-variables-function
2. https://godbolt.org/z/zsodzc

Differential Revision: https://reviews.llvm.org/D88345
2020-11-03 10:30:38 -08:00
Artem Belevich 0a3ebb4d8d Revert "[CUDA] Allow local static variables with target attributes."
This reverts commit f38a9e5117
Which triggered assertions.
2020-11-02 15:09:07 -08:00
Artem Belevich f38a9e5117 [CUDA] Allow local static variables with target attributes.
While CUDA documentation claims that such variables are not allowed[1], NVCC has
been accepting them since CUDA-10.0[2] and some headers in CUDA-11 rely on this
working.

1. https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#static-variables-function
2. https://godbolt.org/z/zsodzc

Differential Revision: https://reviews.llvm.org/D88345
2020-11-02 14:37:13 -08:00
Richard Smith dd8297b066 PR42513: Fix handling of function definitions lazily instantiated from
friends.

When determining whether a function has a template instantiation
pattern, look for other declarations of that function that were
instantiated from a friend function definition, rather than assuming
that checking for member specialization information on whichever
declaration name lookup found will be sufficient.
2020-10-30 18:35:12 -07:00
Richard Smith 09abecef7b PR48002: Fix injection of elaborated-type-specifiers within local
classes into the enclosing block scope.

We weren't properly detecting whether the name would be injected into a
block scope in the case where it was lexically declared in a local
class.
2020-10-28 14:29:45 -07:00
Zequan Wu e56e7bd469 Revert "Revert "Ensure that checkInitIsICE is called exactly once for every variable""
This reverts commit a2ac64dd90.
2020-10-26 12:08:57 -07:00
Zequan Wu a2ac64dd90 Revert "Ensure that checkInitIsICE is called exactly once for every variable"
This causing `Assertion Result && "Could not evaluate expression"' failed` at https://bugs.chromium.org/p/chromium/issues/detail?id=1142009

This reverts commit 76c0092665.
2020-10-26 11:59:55 -07:00
Melanie Blower 2e204e2391 [clang] Enable support for #pragma STDC FENV_ACCESS
Reviewers: rjmccall, rsmith, sepavloff

Differential Revision: https://reviews.llvm.org/D87528
2020-10-25 06:46:25 -07:00
Richard Smith 3692d20d2b Refactor tracking of constant initializers for variables.
Instead of framing the interface around whether the variable is an ICE
(which is only interesting in C++98), primarily track whether the
initializer is a constant initializer (which is interesting in all C++
language modes).

No functionality change intended.
2020-10-19 21:31:19 -07:00
Richard Smith 76c0092665 Ensure that checkInitIsICE is called exactly once for every variable
for which it matters.

This is a step towards separating checking for a constant initializer
(in which std::is_constant_evaluated returns true) and any other
evaluation of a variable initializer (in which it returns false).
2020-10-19 19:04:04 -07:00
Yaxun (Sam) Liu 52bcd691cb Recommit "[CUDA][HIP] Defer overloading resolution diagnostics for host device functions"
This recommits 7f1f89ec8d and
40df06cdaf with bug fixes for
memory sanitizer failure and Tensile build failure.
2020-10-19 17:48:04 -04:00
Richard Smith 552c6c2328 PR44406: Follow behavior of array bound constant folding in more recent versions of GCC.
Old GCC used to aggressively fold VLAs to constant-bound arrays at block
scope in GNU mode. That's non-conforming, and more modern versions of
GCC only do this at file scope. Update Clang to do the same.

Also promote the warning for this from off-by-default to on-by-default
in all cases; more recent versions of GCC likewise warn on this by
default.

This is still slightly more permissive than GCC, as pointed out in
PR44406, as we still fold VLAs to constant arrays in structs, but that
seems justifiable given that we don't support VLA-in-struct (and don't
intend to ever support it), but GCC does.

Differential Revision: https://reviews.llvm.org/D89523
2020-10-16 14:34:35 -07:00
Richard Smith fc031d29be Switch the default of VerifyIntegerConstantExpression from constant
folding to not constant folding.

Constant folding of ICEs is done as a GCC compatibility measure, but new
code was picking it up, presumably by accident, due to the bad default.

While here, also switch the flag from a bool to an enum to make it more
obvious what it means at call sites. This highlighted a couple of places
where our behavior is different between C++11 and C++14 due to switching
from checking for an ICE to checking for a converted constant
expression (where there is no 'fold' codepath).
2020-10-15 16:58:47 -07:00
Ben Dunbobbin bb148ad426 [windows-itanium] make dllimport/export handling closer to MS behavior
Differential Revision: https://reviews.llvm.org/D86828
2020-10-09 13:24:07 +01:00
Ben Dunbobbin a9f1bb92bf Revert "first upstream review"
Pushed by accident :(

This reverts commit 4eb627ed96.
2020-10-09 13:22:46 +01:00
Ben Dunbobbin 4eb627ed96 first upstream review 2020-10-09 13:21:03 +01:00
Richard Smith 1c604a9f5f Recognize setjmp and friends as builtins even if jmp_buf is not declared yet.
This happens in glibc's headers. It's important that we recognize these
functions so that we can mark them as returns_twice.

Differential Revision: https://reviews.llvm.org/D88518
2020-09-29 15:53:17 -07:00
Aaron Ballman 538762fef0 Better diagnostics for anonymous bit-fields with attributes or an initializer.
The current C++ grammar allows an anonymous bit-field with an attribute,
but this is ambiguous (the attribute in that case could appertain to the
type instead of the bit-field). The current thinking in the Core Working
Group is that it's better to disallow attributes in that position at the
grammar level so that the ambiguity resolves in favor of applying to the
type.

During discussions about the behavior of the attribute, the Core Working
Group also felt it was better to disallow anonymous bit-fields from
specifying a default member initializer.

This implements both sets of related grammar changes.
2020-09-29 16:32:20 -04:00
Richard Smith c375635d05 Ensure that we don't compute linkage for an anonymous class too early if
it has a member whose name is the same as a builtin.

Fixes a regression from the introduction of BuiltinAttr.
2020-09-28 17:22:40 -07:00
Saleem Abdulrasool 76eb163259 Sema: remove unnecessary parameter for SwiftName handling (NFCI)
This code never actually did anything in the implementation.

`mergeDeclAttribute` is declared as `static`, and referenced exactly
once in the file: from `Sema::mergeDeclAttributes`.

`Sema::mergeDeclAttributes` sets `LocalAMK` to `AMK_None`.  If the
attribute is `DeprecatedAttr`, `UnavailableAttr`, or `AvailabilityAttr`
then the `LocalAMK` is updated.  However, because we are dealing with a
`SwiftNameDeclAttr` here, `LocalAMK` remains `AMK_None`.  This is then
passed to the function which will as a result pass the value of
`AMK_None == AMK_Override` aka `false`.  Simply propagate the value
through and erase the dead codepath.

Thanks to Aaron Ballman for flagging the use of the availability merge
kind here leading to this simplification!

Differential Revision: https://reviews.llvm.org/D88263
Reviewed By: Aaron Ballman
2020-09-25 17:01:06 +00:00
Reid Kleckner 3453b6928d Revert "Recommit "[CUDA][HIP] Defer overloading resolution diagnostics for host device functions""
This reverts commit e39da8ab6a.

This depends on a change that needs additional design review and needs
to be reverted.
2020-09-24 11:16:54 -07:00
Yaxun (Sam) Liu e39da8ab6a Recommit "[CUDA][HIP] Defer overloading resolution diagnostics for host device functions"
This recommits 7f1f89ec8d and
40df06cdaf after fixing memory
sanitizer failure.
2020-09-24 08:44:37 -04:00
Saleem Abdulrasool 9bb5ecf1f7 Sema: introduce `__attribute__((__swift_name__))`
This introduces the new `swift_name` attribute that allows annotating
APIs with an alternate spelling for Swift.  This is used as part of the
importing mechanism to allow interfaces to be imported with a new name
into Swift.  It takes a parameter which is the Swift function name.
This parameter is validated to check if it matches the possible
transformed signature in Swift.

This is based on the work of the original changes in
8afaf3aad2

Differential Revision: https://reviews.llvm.org/D87534
Reviewed By: Aaron Ballman, Dmitri Gribenko
2020-09-22 15:32:23 +00:00
Raul Tambre f91f28c350 [Sema] Split special builtin type lookups into a separate function
In case further such cases appear in the future we've got a generic function to add them to.
Additionally changed the ObjC special case to check the language and the identifier builtin ID instead of the name.

Addresses the cleanup suggestion from D87917.

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D87983
2020-09-21 19:12:29 +03:00
Raul Tambre a1aa330b20 [Sema] Handle objc_super special lookup when checking builtin compatibility
objc_super is special and needs LookupPredefedObjCSuperType() called before performing builtin type comparisons.
This fixes an error when compiling macOS headers. A test is added.

Differential Revision: https://reviews.llvm.org/D87917
2020-09-18 20:51:55 +03:00
Yaxun (Sam) Liu 772bd8a7d9 Revert "[CUDA][HIP] Defer overloading resolution diagnostics for host device functions"
This reverts commit 7f1f89ec8d.

This reverts commit 40df06cdaf.
2020-09-17 13:55:31 -04:00
Raul Tambre e09107ab80 [Sema] Introduce BuiltinAttr, per-declaration builtin-ness
Instead of relying on whether a certain identifier is a builtin, introduce BuiltinAttr to specify a declaration as having builtin semantics.

This fixes incompatible redeclarations of builtins, as reverting the identifier as being builtin due to one incompatible redeclaration would have broken rest of the builtin calls.
Mostly-compatible redeclarations of builtins also no longer have builtin semantics. They don't call the builtin nor inherit their attributes.
A long-standing FIXME regarding builtins inside a namespace enclosed in extern "C" not being recognized is also addressed.

Due to the more correct handling attributes for builtin functions are added in more places, resulting in more useful warnings.
Tests are updated to reflect that.

Intrinsics without an inline definition in intrin.h had `inline` and `static` removed as they had no effect and caused them to no longer be recognized as builtins otherwise.

A pthread_create() related test is XFAIL-ed, as it relied on it being recognized as a builtin based on its name.
The builtin declaration syntax is too restrictive and doesn't allow custom structs, function pointers, etc.
It seems to be the only case and fixing this would require reworking the current builtin syntax, so this seems acceptable.

Fixes PR45410.

Reviewed By: rsmith, yutsumi

Differential Revision: https://reviews.llvm.org/D77491
2020-09-17 19:28:57 +03:00
Yaxun (Sam) Liu 40df06cdaf [CUDA][HIP] Defer overloading resolution diagnostics for host device functions
In CUDA/HIP a function may become implicit host device function by
pragma or constexpr. A host device function is checked in both
host and device compilation. However it may be emitted only
on host or device side, therefore the diagnostics should be
deferred until it is known to be emitted.

Currently clang is only able to defer certain diagnostics. This causes
false alarms and limits the usefulness of host device functions.

This patch lets clang defer all overloading resolution diagnostics for host device functions.

An option -fgpu-defer-diag is added to control this behavior. By default
it is off.

It is NFC for other languages.

Differential Revision: https://reviews.llvm.org/D84364
2020-09-17 11:30:42 -04:00
Amy Huang bebfc3b92d Revert "Do not apply calling conventions to MSVC entry points"
This reverts commit 4cff1b40da.

Caused "undefined symbol: _WinMain@16" link errors.
2020-09-16 13:52:29 -07:00
Johannes Doerfert 5c1084e884 [OpenMP] Context selector extensions for template functions
With this extension the effects of `omp begin declare variant` will be
applied to template function declarations. The behavior is opt-in and
controlled by the `extension(allow_templates)` trait. While generally
useful, this will enable us to implement complex math function calls by
overloading the templates of the standard library with the ones in
libc++.

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D85735
2020-09-16 13:37:10 -05:00
Elizabeth Andrews 4cff1b40da Do not apply calling conventions to MSVC entry points
Fix link error for MSVC entry points when calling conventions
are specified. MSVC entry points should have default calling
convention.

Differential Revision: https://reviews.llvm.org/D87701
2020-09-16 09:39:37 -07:00
Serge Pavlov f1cd6593da [AST][FPEnv] Keep FP options in trailing storage of CastExpr
This is recommit of 6c8041aa0f, reverted in de044f7562 because of some
fails. Original commit message is below.

This change allow a CastExpr to have optional FPOptionsOverride object,
stored in trailing storage. Of all cast nodes only ImplicitCastExpr,
CStyleCastExpr, CXXFunctionalCastExpr and CXXStaticCastExpr are allowed
to have FPOptions.

Differential Revision: https://reviews.llvm.org/D85960
2020-09-14 12:15:21 +07:00
Serge Pavlov de044f7562 Revert "[AST][FPEnv] Keep FP options in trailing storage of CastExpr"
This reverts commit 6c8041aa0f.
It caused some fails on buildbots.
2020-09-12 17:06:42 +07:00
Serge Pavlov 6c8041aa0f [AST][FPEnv] Keep FP options in trailing storage of CastExpr
This change allow a CastExpr to have optional FPOptionsOverride object,
stored in trailing storage. Of all cast nodes only ImplicitCastExpr,
CStyleCastExpr, CXXFunctionalCastExpr and CXXStaticCastExpr are allowed
to have FPOptions.

Differential Revision: https://reviews.llvm.org/D85960
2020-09-12 14:30:44 +07:00
Aaron Puchert 85fce449dc [Sema] Simplify ShouldDiagnoseUnusedDecl, NFC
Instead of writing to a flag and then returning based on that flag we
can also return directly. The flag name also doesn't provide additional
information, it just reflects the name of the function (isReferenced).
2020-08-29 18:42:58 +02:00
Cullen Rhodes feed5a7239 [Sema][AArch64] Support arm_sve_vector_bits attribute
This patch implements the semantics for the 'arm_sve_vector_bits' type
attribute, defined by the Arm C Language Extensions (ACLE) for SVE [1].
The purpose of this attribute is to define vector-length-specific (VLS)
versions of existing vector-length-agnostic (VLA) types.

The semantics were already implemented by D83551, although the
implementation approach has since changed to represent VLSTs as
VectorType in the AST and fixed-length vectors in the IR everywhere
except in function args/returns. This is described in the prototype
patch D85128 demonstrating the new approach.

The semantic changes added in D83551 are changed since the
AttributedType is replaced by VectorType in the AST. Minimal changes
were necessary in the previous patch as the canonical type for both VLA
and VLS was the same (i.e. sizeless), except in constructs such as
globals and structs where sizeless types are unsupported. This patch
reverts the changes that permitted VLS types that were represented as
sizeless types in such circumstances, and adds support for implicit
casting between VLA <-> VLS types as described in section 3.7.3.2 of the
ACLE.

Since the SVE builtin types for bool and uint8 are both represented as
BuiltinType::UChar in VLSTs, two new vector kinds are implemented to
distinguish predicate and data vectors.

[1] https://developer.arm.com/documentation/100987/latest

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D85736
2020-08-27 10:38:32 +00:00
Jon Chesterfield bcaa806a47 [Clang] Fix BZ47169, loader_uninitialized on incomplete types
[Clang] Fix BZ47169, loader_uninitialized on incomplete types

Reported by @erichkeane. Fix proposed by @erichkeane works, tests included.
Bug introduced in D74361. Crash was on querying a CXXRecordDecl for
hasTrivialDefaultConstructor on an incomplete type. Fixed by calling
RequireCompleteType in the right place.

Reviewed By: erichkeane

Differential Revision: https://reviews.llvm.org/D85990
2020-08-19 18:11:50 +01:00
Dávid Bolvanský 2f7adf5ee3 [Diagnostics] Skip var decl of structs for -Wstring-concatenation 2020-08-13 20:20:26 +02:00
Dávid Bolvanský b9af72bffe [Diagnostics] Reworked -Wstring-concatenation 2020-08-12 02:18:01 +02:00
Erich Keane 0a8ac91a08 Permit nowthrow and nonnull with multiversioning.
Some shipped versions of stdlib.h use nonnull and nothrow with function
multiversioning.  Support these, as they are generally harmless.
2020-08-04 07:40:27 -07:00
Erich Keane 961da69d7e Improve diagnostics for disallowed attributes used with multiversioning
Since we permit using SOME attributes (at the moment, just 1) with
multiversioning, we should improve the message as it still implies that
no attributes should be combined with multiversioning.
2020-08-04 07:40:27 -07:00
Richard Smith a648834313 PR46729: Reject explicit and partial specializations with C linkage. 2020-07-29 17:44:32 -07:00
Richard Smith 1cbdf932b4 PR46231: Promote diagnostic for 'template<...>;' from ExtWarn to Error.
No other compiler accepts this as an extension, not even in permissive
mode. We're not doing anyone any favors by allowing this, and it's
unlikely to be at all common, even in Clang-only code, in the wild.
2020-07-29 12:35:18 -07:00
Bruno Ricci eb10b065f2
[clang] Pass the NamedDecl* instead of the DeclarationName into many diagnostics.
Background:
-----------
There are two related argument types which can be sent into a diagnostic to
display the name of an entity: DeclarationName (ak_declarationname) or
NamedDecl* (ak_nameddecl) (there is also ak_identifierinfo for
IdentifierInfo*, but we are not concerned with it here).

A DeclarationName in a diagnostic will just be streamed to the output,
which will directly result in a call to DeclarationName::print.

A NamedDecl* in a diagnostic will also ultimately result in a call to
DeclarationName::print, but with two customisation points along the way:

The first customisation point is NamedDecl::getNameForDiagnostic which is
overloaded by FunctionDecl, ClassTemplateSpecializationDecl and
VarTemplateSpecializationDecl to print the template arguments, if any.

The second customisation point is NamedDecl::printName. By default it just
streams the stored DeclarationName into the output but it can be customised
to provide a user-friendly name for an entity. It is currently overloaded by
DecompositionDecl and MSGuidDecl.

What this patch does:
---------------------
For many diagnostics a DeclarationName is used instead of the NamedDecl*.
This bypasses the two customisation points mentioned above. This patches fix
this for diagnostics in Sema.cpp, SemaCast.cpp, SemaChecking.cpp, SemaDecl.cpp,
SemaDeclAttr.cpp, SemaDecl.cpp, SemaOverload.cpp and SemaStmt.cpp.

I have only modified diagnostics where I could construct a test-case which
demonstrates that the change is appropriate (either with this patch or the next
one).

Reviewed By: erichkeane, aaron.ballman

Differential Revision: https://reviews.llvm.org/D84656
2020-07-28 10:30:35 +01:00
Richard Smith 23d6525cbd Don't form a 'context-independent expr' reference to a member during
name annotation.

Instead, defer forming the member access expression or DeclRefExpr until
we build the use of ClassifyName's result. Just build an
UnresolvedLookupExpr to track the LookupResult until we're ready to
consume it.

This also reverts commit 2f7269b677 (other
than its testcase). That change was an attempted workaround for the same
problem.
2020-07-27 19:38:22 -07:00
Cullen Rhodes 89e61e782b [Sema][AArch64] Add semantics for arm_sve_vector_bits attribute
Summary:
This patch implements semantics for the 'arm_sve_vector_bits' type
attribute, defined by the Arm C Language Extensions (ACLE) for SVE [1].
The purpose of this attribute is to define fixed-length (VLST) versions
of existing sizeless types (VLAT).

Implemented in this patch is the the behaviour described in section 3.7.3.2
and minimal parts of sections 3.7.3.3 and 3.7.3.4, this includes:

    * Defining VLST globals, structs, unions, and local variables
    * Implicit casting between VLAT <=> VLST.
    * Diagnosis of ill-formed conditional expressions of the form:

        C ?  E1 : E2

      where E1 is a VLAT type and E2 is a VLST, or vice-versa. This
      avoids any ambiguity about the nature of the result type (i.e is
      it sized or sizeless).
    * For vectors:
        * sizeof(VLST) == N/8
        * alignof(VLST) == 16
    * For predicates:
        * sizeof(VLST) == N/64
        * alignof(VLST) == 2

VLSTs have the same representation as VLATs in the AST but are wrapped
with a TypeAttribute. Scalable types are currently emitted in the IR for
uses such as globals and structs which don't support these types, this
is addressed in the next patch with codegen, where VLSTs are lowered to
sized arrays for globals, structs / unions and arrays.

Not implemented in this patch is the behaviour guarded by the feature
macros:

    * __ARM_FEATURE_SVE_VECTOR_OPERATORS
    * __ARM_FEATURE_SVE_PREDICATE_OPERATORS

As such, the GNU __attribute__((vector_size)) extension is not available
and operators such as binary '+' are not supported for VLSTs. Support
for this is intended to be addressed by later patches.

[1] https://developer.arm.com/documentation/100987/latest

This is patch 2/4 of a patch series.

Reviewers: sdesmalen, rsandifo-arm, efriedma, cameron.mcinally, ctetreau, rengolin, aaron.ballman

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D83551
2020-07-22 16:26:23 +00:00