Commit Graph

971 Commits

Author SHA1 Message Date
Kazu Hirata 8595f2e54d [Sema] Use std::nullopt instead of None (NFC)
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2022-12-03 11:13:39 -08:00
Rageking8 94738a5ac3 Fix duplicate word typos; NFC
This revision fixes typos where there are 2 consecutive words which are
duplicated. There should be no code changes in this revision (only
changes to comments and docs). Do let me know if there are any
undesirable changes in this revision. Thanks.
2022-11-08 07:21:23 -05:00
Kazu Hirata 94186347a1 [clang] Use llvm::reverse (NFC) 2022-11-06 21:09:20 -08:00
Corentin Jabot d0d2772379 [Clang] Implement P2513
Implement P2513

This change allows initializing an array of unsigned char,
or char from u8 string literals.
This was done both to support legacy code and for compatibility
with C where char8_t will be typedef to unsigned char.

This is backported to C++20 as per WG21 guidance.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D136449
2022-10-24 18:10:43 +02:00
Xiang Li 464926ef44 [HLSL] Disable integer promotion to avoid int16_t being promoted to int for HLSL.
short will be promoted to int in UsualUnaryConversions.
Disable it for HLSL to keep int16_t as 16bit.

Reviewed By: aaron.ballman, rjmccall

Differential Revision: https://reviews.llvm.org/D133668
2022-10-20 16:06:25 -07:00
Roy Jacobson 9415aad6a4 [Clang] Fix variant crashes from GH58028, GH57370
Fixes a null dereference in some diagnostic issuing code.

Closes https://github.com/llvm/llvm-project/issues/57370
Closes https://github.com/llvm/llvm-project/issues/58028

Reviewed By: shafik

Differential Revision: https://reviews.llvm.org/D134885
2022-09-30 21:17:34 +03:00
Roy Jacobson 894c0e94f9 Revert "[Clang] Fix variant crashes from GH58028, GH57370"
This reverts commit 9706bb3165, some CI workers complain about the test.
2022-09-30 11:24:46 +03:00
Roy Jacobson 9706bb3165 [Clang] Fix variant crashes from GH58028, GH57370
Fixes a null dereference in some diagnostic issuing code.

Closes https://github.com/llvm/llvm-project/issues/57370
Closes https://github.com/llvm/llvm-project/issues/58028

Reviewed By: shafik

Differential Revision: https://reviews.llvm.org/D134885
2022-09-30 11:09:02 +03:00
Roy Jacobson 6523814c4e [Clang] P1169R4: static operator()
Implements 'P1169R4: static operator()' from C++2b.

Reviewed By: #clang-language-wg, aaron.ballman

Differential Revision: https://reviews.llvm.org/D133659
2022-09-29 23:03:26 +03:00
Kazu Hirata b7a7aeee90 [clang] Qualify auto in range-based for loops (NFC) 2022-09-03 23:27:27 -07:00
Timm Bäder 3d2ab237f1 [clang] Improve diagnostics for uninitialized constexpr variables
Instead of complaining about default initialization, tell users that
constexpr variables need to be initialized by a constant expression.

Differential Revision: https://reviews.llvm.org/D131662
2022-08-19 08:06:12 +02:00
Fangrui Song 3f18f7c007 [clang] LLVM_FALLTHROUGH => [[fallthrough]]. NFC
With C++17 there is no Clang pedantic warning or MSVC C5051.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D131346
2022-08-08 09:12:46 -07:00
Corentin Jabot 127bf44385 [Clang][C++20] Support capturing structured bindings in lambdas
This completes the implementation of P1091R3 and P1381R1.

This patch allow the capture of structured bindings
both for C++20+ and C++17, with extension/compat warning.

In addition, capturing an anonymous union member,
a bitfield, or a structured binding thereof now has a
better diagnostic.

We only support structured bindings - as opposed to other kinds
of structured statements/blocks. We still emit an error for those.

In addition, support for structured bindings capture is entirely disabled in
OpenMP mode as this needs more investigation - a specific diagnostic indicate the feature is not yet supported there.

Note that the rest of P1091R3 (static/thread_local structured bindings) was already implemented.

at the request of @shafik, i can confirm the correct behavior of lldb wit this change.

Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/52720

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D122768
2022-08-04 10:12:53 +02:00
Corentin Jabot a274219600 Revert "[Clang][C++20] Support capturing structured bindings in lambdas"
This reverts commit 44f2baa380.

Breaks self builds and seems to have conformance issues.
2022-08-03 21:00:29 +02:00
Corentin Jabot 44f2baa380 [Clang][C++20] Support capturing structured bindings in lambdas
This completes the implementation of P1091R3 and P1381R1.

This patch allow the capture of structured bindings
both for C++20+ and C++17, with extension/compat warning.

In addition, capturing an anonymous union member,
a bitfield, or a structured binding thereof now has a
better diagnostic.

We only support structured bindings - as opposed to other kinds
of structured statements/blocks. We still emit an error for those.

In addition, support for structured bindings capture is entirely disabled in
OpenMP mode as this needs more investigation - a specific diagnostic indicate the feature is not yet supported there.

Note that the rest of P1091R3 (static/thread_local structured bindings) was already implemented.

at the request of @shafik, i can confirm the correct behavior of lldb wit this change.

Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/52720

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D122768
2022-08-03 20:00:01 +02:00
Corentin Jabot a9a60f20e6 [Clang] Rename StringLiteral::isAscii() => isOrdinary() [NFC]
"Ascii" StringLiteral instances are actually narrow strings
that are UTF-8 encoded and do not have an encoding prefix.
(UTF8 StringLiteral are also UTF-8 encoded strings, but with
the u8 prefix.

To avoid possible confusion both with actuall ASCII strings,
and with future works extending the set of literal encodings
supported by clang, this rename StringLiteral::isAscii() to
isOrdinary(), matching C++ standard terminology.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D128762
2022-06-29 18:28:51 +02:00
Haojian Wu 7b7166f1a2 Fix an unused-variable warning in release build, NFC. 2022-06-21 20:52:07 +02:00
Chris Bieneman 9f499d9d73 [HLSL] Support HLSL vector initializers
In HLSL vectors are ext_vectors in all respects except that they
support a constructor style syntax for initializing vectors. This
change adds a translation of vector constructor arguments into
initializer lists.

This supports two oddities of HLSL syntax:
(1) HLSL vectors support constructor syntax
(2) HLSL vectors are expanded to constituate components in constructors

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D127802
2022-06-21 12:33:42 -05:00
Akira Hatanaka 66e08995b0 [Sema] Reject list-initialization of enumeration types from a
brace-init-list containing a single element of a different scoped
enumeration type

It is rejected because it doesn't satisfy the condition that the element
has to be implicitly convertible to the underlying type of the
enumeration.

http://eel.is/c++draft/dcl.init.list#3.8

Differential Revision: https://reviews.llvm.org/D126084
2022-06-02 17:25:11 -07:00
Bill Wendling f2639cf3fe [randstruct] Move initializer check to be more effective
If a randomized structure has an initializer with a dedicated
initializer in it, the field initialzed by that dedicated initializer
may end up at the end of the RecordDecl. This however may skip the
random layout initization check.

  struct t {
     int a, b, c, d, e;
  } x = { .a = 2, 4, 5, 6 };

Let's say that "a" is lands as the last field after randomization. The
call to CheckDesignatedInitializer sets the iterator to the end of the
initializer list. During the next iteration of the initializer list
check, it detects that and fails to issue the error about initializing
a randomized struct with non-designated initializer. Instead, it issues
an error about "excess elements in struct initializer", which is
confusing under these circumstances.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D124694
2022-05-03 11:23:12 -07:00
Bill Wendling 463790bfc7 [randstruct] Randomize all elements of a record
A record may have more than just FieldDecls in it. If so, then we're
likely to drop them if we only randomize the FieldDecls.

We need to be careful about anonymous structs/unions. Their fields are
made available in the RecordDecl as IndirectFieldDecls, which are listed
after the anonymous struct/union. The ordering doesn't appear to be
super important, however we place them unrandomized at the end of the
RecordDecl just in case. There's also the possiblity of
StaticAssertDecls. We also want those at the end.

All other non-FieldDecls we place at the top, just in case we get
something like:

    struct foo {
      enum e { BORK };
      enum e a;
    };

Link: https://github.com/KSPP/linux/issues/185

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D123958
2022-04-28 12:01:11 -07:00
Richard Smith 72315d02c4 Treat `std::move`, `forward`, etc. as builtins.
This is extended to all `std::` functions that take a reference to a
value and return a reference (or pointer) to that same value: `move`,
`forward`, `move_if_noexcept`, `as_const`, `addressof`, and the
libstdc++-specific function `__addressof`.

We still require these functions to be declared before they can be used,
but don't instantiate their definitions unless their addresses are
taken. Instead, code generation, constant evaluation, and static
analysis are given direct knowledge of their effect.

This change aims to reduce various costs associated with these functions
-- per-instantiation memory costs, compile time and memory costs due to
creating out-of-line copies and inlining them, code size at -O0, and so
on -- so that they are not substantially more expensive than a cast.
Most of these improvements are very small, but I measured a 3% decrease
in -O0 object file size for a simple C++ source file using the standard
library after this change.

We now automatically infer the `const` and `nothrow` attributes on these
now-builtin functions, in particular meaning that we get a warning for
an unused call to one of these functions.

In C++20 onwards, we disallow taking the addresses of these functions,
per the C++20 "addressable function" rule. In earlier language modes, a
compatibility warning is produced but the address can still be taken.

The same infrastructure is extended to the existing MSVC builtin
`__GetExceptionInfo`, which is now only recognized in namespace `std`
like it always should have been.

This is a re-commit of
  fc30901096,
  a571f82a50,
  64c045e25b, and
  de6ddaeef3,
and reverts aa643f455a.
This change also includes a workaround for users using libc++ 3.1 and
earlier (!!), as apparently happens on AIX, where std::move sometimes
returns by value.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D123345

Revert "Fixup D123950 to address revert of D123345"

This reverts commit aa643f455a.
2022-04-20 17:58:31 -07:00
David Tenty 98d911e01f Revert "Treat `std::move`, `forward`, etc. as builtins."
This reverts commit b27430f9f4 as the
    parent https://reviews.llvm.org/D123345 breaks the AIX CI:

    https://lab.llvm.org/buildbot/#/builders/214/builds/819
2022-04-20 19:14:37 -04:00
Nathan James cfb8169059
[clang] Add a raw_ostream operator<< overload for QualType
Under the hood this prints the same as `QualType::getAsString()` but cuts out the middle-man when that string is sent to another raw_ostream.

Also cleaned up all the call sites where this occurs.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D123926
2022-04-20 22:09:05 +01:00
Richard Smith b27430f9f4 Treat `std::move`, `forward`, etc. as builtins.
This is extended to all `std::` functions that take a reference to a
value and return a reference (or pointer) to that same value: `move`,
`forward`, `move_if_noexcept`, `as_const`, `addressof`, and the
libstdc++-specific function `__addressof`.

We still require these functions to be declared before they can be used,
but don't instantiate their definitions unless their addresses are
taken. Instead, code generation, constant evaluation, and static
analysis are given direct knowledge of their effect.

This change aims to reduce various costs associated with these functions
-- per-instantiation memory costs, compile time and memory costs due to
creating out-of-line copies and inlining them, code size at -O0, and so
on -- so that they are not substantially more expensive than a cast.
Most of these improvements are very small, but I measured a 3% decrease
in -O0 object file size for a simple C++ source file using the standard
library after this change.

We now automatically infer the `const` and `nothrow` attributes on these
now-builtin functions, in particular meaning that we get a warning for
an unused call to one of these functions.

In C++20 onwards, we disallow taking the addresses of these functions,
per the C++20 "addressable function" rule. In earlier language modes, a
compatibility warning is produced but the address can still be taken.

The same infrastructure is extended to the existing MSVC builtin
`__GetExceptionInfo`, which is now only recognized in namespace `std`
like it always should have been.

This is a re-commit of
  fc30901096,
  a571f82a50, and
  64c045e25b
which were reverted in
  e75d8b7037
due to a crasher bug where CodeGen would emit a builtin glvalue as an
rvalue if it constant-folds.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D123345
2022-04-17 13:26:16 -07:00
Bill Wendling 7f31b4a917 [randstruct] Enforce using a designated init for a randomized struct
A randomized structure needs to use a designated or default initializer.
Using a non-designated initializer will result in values being assigned
to the wrong fields.

Differential Revision: https://reviews.llvm.org/D123763
2022-04-16 23:24:48 -07:00
Aaron Ballman 7692fc81e0 Revert "[randstruct] Enforce using a designated init for a randomized struct"
This reverts commit aed923b124.

It causes some buildbot test failures.
2022-04-16 11:11:32 -04:00
Vitaly Buka e75d8b7037 Revert "Treat `std::move`, `forward`, and `move_if_noexcept` as builtins."
Revert "Extend support for std::move etc to also cover std::as_const and"
Revert "Update test to handle opaque pointers flag flip."

It crashes on libcxx tests https://lab.llvm.org/buildbot/#/builders/85/builds/8174

This reverts commit fc30901096.
This reverts commit a571f82a50.
This reverts commit 64c045e25b.
2022-04-16 00:27:51 -07:00
Richard Smith 64c045e25b Treat `std::move`, `forward`, and `move_if_noexcept` as builtins.
We still require these functions to be declared before they can be used,
but don't instantiate their definitions unless their addresses are
taken. Instead, code generation, constant evaluation, and static
analysis are given direct knowledge of their effect.

This change aims to reduce various costs associated with these functions
-- per-instantiation memory costs, compile time and memory costs due to
creating out-of-line copies and inlining them, code size at -O0, and so
on -- so that they are not substantially more expensive than a cast.
Most of these improvements are very small, but I measured a 3% decrease
in -O0 object file size for a simple C++ source file using the standard
library after this change.

We now automatically infer the `const` and `nothrow` attributes on these
now-builtin functions, in particular meaning that we get a warning for
an unused call to one of these functions.

In C++20 onwards, we disallow taking the addresses of these functions,
per the C++20 "addressable function" rule. In earlier language modes, a
compatibility warning is produced but the address can still be taken.

The same infrastructure is extended to the existing MSVC builtin
`__GetExceptionInfo`, which is now only recognized in namespace `std`
like it always should have been.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D123345
2022-04-15 14:09:45 -07:00
Bill Wendling aed923b124 [randstruct] Enforce using a designated init for a randomized struct
A randomized structure needs to use a designated or default initializer.
Using a non-designated initializer will result in values being assigned
to the wrong fields.

Differential Revision: https://reviews.llvm.org/D123763
2022-04-15 12:29:32 -07:00
Eli Friedman 5955a0f937 Allow flexible array initialization in C++.
Flexible array initialization is a C/C++ extension implemented in many
compilers to allow initializing the flexible array tail of a struct type
that contains a flexible array. In clang, this is currently restricted
to C. But this construct is used in the Microsoft SDK headers, so I'd
like to extend it to C++.

For now, this doesn't handle dynamic initialization; probably not hard
to implement, but it's extra code, and I don't think it's necessary for
the expected uses.  And we explicitly fail out of constant evaluation.

I've added some additional code to assert that initializers have the
correct size, with or without flexible array init. This might catch
issues unrelated to flexible array init.

Differential Revision: https://reviews.llvm.org/D123649
2022-04-14 11:56:40 -07:00
Kazu Hirata f1c159cc90 [Format, Sema] Use range-based for loops with llvm::reverse (NFC) 2021-11-17 08:52:35 -08:00
Matheus Izvekov c9e46219f3
[clang] retain type sugar in auto / template argument deduction
This implements the following changes:
* AutoType retains sugared deduced-as-type.
* Template argument deduction machinery analyses the sugared type all the way
down. It would previously lose the sugar on first recursion.
* Undeduced AutoType will be properly canonicalized, including the constraint
template arguments.
* Remove the decltype node created from the decltype(auto) deduction.

As a result, we start seeing sugared types in a lot more test cases,
including some which showed very unfriendly `type-parameter-*-*` types.

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

Reviewed By: rsmith, #libc, ldionne

Differential Revision: https://reviews.llvm.org/D110216
2021-11-15 23:07:45 +01:00
Matheus Izvekov 6438a52df1
Revert "[clang] retain type sugar in auto / template argument deduction"
This reverts commit 4d8fff477e.
2021-11-15 00:29:05 +01:00
Matheus Izvekov 4d8fff477e
[clang] retain type sugar in auto / template argument deduction
This implements the following changes:
* AutoType retains sugared deduced-as-type.
* Template argument deduction machinery analyses the sugared type all the way
down. It would previously lose the sugar on first recursion.
* Undeduced AutoType will be properly canonicalized, including the constraint
template arguments.
* Remove the decltype node created from the decltype(auto) deduction.

As a result, we start seeing sugared types in a lot more test cases,
including some which showed very unfriendly `type-parameter-*-*` types.

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

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D110216
2021-11-13 03:35:22 +01:00
Adrian Kuegel 1d7fdbbc18 Revert "[clang] retain type sugar in auto / template argument deduction"
This reverts commit 9b6036deed.
Breaks two libc++ tests.
2021-11-12 13:21:59 +01:00
Matheus Izvekov 9b6036deed
[clang] retain type sugar in auto / template argument deduction
This implements the following changes:
* AutoType retains sugared deduced-as-type.
* Template argument deduction machinery analyses the sugared type all the way
down. It would previously lose the sugar on first recursion.
* Undeduced AutoType will be properly canonicalized, including the constraint
template arguments.
* Remove the decltype node created from the decltype(auto) deduction.

As a result, we start seeing sugared types in a lot more test cases,
including some which showed very unfriendly `type-parameter-*-*` types.

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

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D110216
2021-11-12 01:16:31 +01:00
Kazu Hirata d409048201 [Sema] Use llvm::is_contained (NFC) 2021-10-11 11:06:44 -07:00
Zequan Wu dbaa408336 [clang] do not emit note for bad conversion when destination type qualifiers are not compatibly include source type qualifiers
llvm.org/PR52014

Differential Revision: https://reviews.llvm.org/D110780
2021-09-30 11:24:18 -07:00
Nico Weber bde305baf6 [clang] Fix a few comment more typos to cycle bots 2021-09-20 19:42:49 -04:00
Richard Smith ea1c01dde0 PR51105: look through ConstantExpr when looking for a braced string literal initialization. 2021-08-25 11:36:11 -07:00
Matheus Izvekov 4819b751bd [clang] NFC: change uses of `Expr->getValueKind` into `is?Value`
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D100733
2021-07-28 03:09:31 +02:00
Ole Strohm 78d309ce19 [OpenCL] Fix qualifiers check on binding references to temporaries
Fix the qualifiers check from PR49733.

Fixes: PR49733

Reviewed By: Anastasia

Differential Revision: https://reviews.llvm.org/D103962
2021-06-29 10:03:57 +01:00
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
Matheus Izvekov c25572bf29 [clang] NFC: rename SK_CastDerivedToBaseRValue to SK_CastDerivedToBasePRValue
This is a follow up to the "rvalue-to-prvalue" rename at D103720.

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

Depends on D103720

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D103933
2021-06-09 12:38:59 +02:00
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
Hana Dusíková 64c24f493e Remove warning "suggest braces" for aggregate initialization of an empty class with an aggregate base class.
I recently ran into issues with aggregates and inheritance, I'm using
it for creating a type-safe library where most of the types are build
over "tagged" std::array. After bit of cleaning and enabling -Wall
-Wextra -pedantic I noticed clang only in my pipeline gives me warning.
After a bit of focusing on it I found it's not helpful, and contemplate
disabling the warning all together. After a discussion with other
library authors I found it's bothering more people and decided to fix
it.

Removes this warning:

template<typename T, int N> struct StdArray {
    T contents[N];
  };

template<typename T, int N> struct AggregateAndEmpty : StdArray<T,N> { };

AggregateAndEmpty<int, 3> p = {1, 2, 3}; // <-- warning here about omitted braces
2021-04-13 15:45:09 -04:00
Joshua Haberman c3134d7c44 [clang] Replaced some manual pointer tagging with llvm::PointerIntPair.
There is no functional change here (hence no new tests). The only change
is to replace a couple uintptr_t members with llvm::PointerIntPair<> to
clean up the code, making it more readable and less error prone.

This cleanup highlighted that the old code was effectively casting away
const. This is fixed by changing some function signatures.

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D98889
2021-03-22 14:13:42 -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
Tomas Matheson 7e5cea5b50 [Clang][Sema] Warn when function argument is less aligned than parameter
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
2021-03-09 10:37:32 +00:00