Commit Graph

3053 Commits

Author SHA1 Message Date
Marco Elver c65186c89f [clang] Improve -Wdeclaration-after-statement
With 118f966b46, Clang matches GCC's behaviour and allows enabling
-Wdeclaration-after-statement with C99 and later.

However, the check for mixing declarations and code is not a constant time
algorithm, and therefore should be guarded with Diags.isIgnored().

Furthermore, improve test coverage with: non-pedantic C89 with the
warning; C11 with the warning; and when using -Wall.

Finally, mention the changed behaviour in ReleaseNotes.rst.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D117232
2022-01-20 19:56:34 +01:00
Evgeny Shulgin b80db150cd Add `isConsteval` matcher
Support C++20 consteval functions and C++2b if consteval for AST Matchers.
2022-01-20 13:35:10 -05:00
Alexandre Ganea 5af2433e17 [clang-cl] Support the /HOTPATCH flag
This patch adds support for the MSVC /HOTPATCH flag: https://docs.microsoft.com/sv-se/cpp/build/reference/hotpatch-create-hotpatchable-image?view=msvc-170&viewFallbackFrom=vs-2019

The flag is translated to a new -fms-hotpatch flag, which in turn adds a 'patchable-function' attribute for each function in the TU. This is then picked up by the PatchableFunction pass which would generate a TargetOpcode::PATCHABLE_OP of minsize = 2 (which means the target instruction must resolve to at least two bytes). TargetOpcode::PATCHABLE_OP is only implemented for x86/x64. When targetting ARM/ARM64, /HOTPATCH isn't required (instructions are always 2/4 bytes and suitable for hotpatching).

Additionally, when using /Z7, we generate a 'hot patchable' flag in the CodeView debug stream, in the S_COMPILE3 record. This flag is then picked up by LLD (or link.exe) and is used in conjunction with the linker /FUNCTIONPADMIN flag to generate extra space before each function, to accommodate for live patching long jumps. Please see: d703b92296/lld/COFF/Writer.cpp (L1298)

The outcome is that we can finally use Live++ or Recode along with clang-cl.

NOTE: It seems that MSVC cl.exe always enables /HOTPATCH on x64 by default, although if we did the same I thought we might generate sub-optimal code (if this flag was active by default). Additionally, MSVC always generates a .debug$S section and a S_COMPILE3 record, which Clang doesn't do without /Z7. Therefore, the following MSVC command-line "cl /c file.cpp" would have to be written with Clang such as "clang-cl /c file.cpp /HOTPATCH /Z7" in order to obtain the same result.

Depends on D43002, D80833 and D81301 for the full feature.

Differential Revision: https://reviews.llvm.org/D116511
2022-01-20 12:57:19 -05:00
Marek Kurdej 5ea98988c6 [clang-format] [docs] Fix link to avoid redirection. NFC. 2022-01-19 14:23:04 +01:00
Saiyedul Islam 6ee9654713
[Doc] Fix wrong indentation
Handle Sphinx's warning at line 218.
2022-01-19 11:15:31 +00:00
Saiyedul Islam 0731f6ba4f
[Doc] Add documentation for the clang-offload-wrapper tool (NFC)
Add the missing documentation for this tool.

Reviewed By: sdmitriev

Differential Revision: https://reviews.llvm.org/D117120
2022-01-19 10:45:13 +00:00
Aaron Ballman 0d459444e5 Mark ATOMIC_VAR_INIT and ATOMIC_FLAG_INIT as deprecated
C17 deprecated ATOMIC_VAR_INIT with the resolution of DR 485. C++
followed suit when adopting P0883R2 for C++20, but additionally chose
to deprecate ATOMIC_FLAG_INIT at the same time despite the macro still
being required in C. This patch marks both macros as deprecated when
appropriate to do so.
2022-01-18 13:41:56 -05:00
Sam McCall 16949762dc [docs] Clarify & update JSONCompilationDatabase docs
- prefer `arguments` over `command`, and add example
- clarify that there's no shell-unescaping of `arguments`

Fixes https://github.com/llvm/llvm-project/issues/53143

Differential Revision: https://reviews.llvm.org/D117428
2022-01-17 09:51:55 +01:00
Cameron Mulhern 966f24e5a6 [clang-format] Add a BlockIndent option to AlignAfterOpenBracket
This style is similar to AlwaysBreak, but places closing brackets on new lines.

For example, if you have a multiline parameter list, clang-format currently only supports breaking per-parameter, but places the closing bracket on the line of the last parameter.

Function(
    param1,
    param2,
    param3);

A style supported by other code styling tools (e.g. rustfmt) is to allow the closing brackets to be placed on their own line, aiding the user in being able to quickly infer the bounds of the block of code.

Function(
    param1,
    param2,
    param3
);

For prior work on a similar feature, see: https://reviews.llvm.org/D33029.

Note: This currently only supports block indentation for closing parentheses.

Differential Revision: https://reviews.llvm.org/D109557
2022-01-17 09:03:23 +01:00
Owen Pan 533fbae8d8 [clang-format] Add experimental option to remove LLVM braces
See the style examples at:
https://llvm.org/docs/CodingStandards.html#don-t-use-braces-on-simple-single-statement-bodies-of-if-else-loop-statements

Differential Revision: https://reviews.llvm.org/D116316
2022-01-14 15:10:17 -08:00
serge-sans-paille 6cacd420a1 Document several clang-supported builtins
Namely
__builtin_alloca
__builtin_alloca_with_align
__builtin_call_with_static_chain
__builtin_expect
__builtin_expect_with_probablity
__builtin_prefetch

Differential Revision: https://reviews.llvm.org/D117296
2022-01-14 22:03:56 +01:00
Andrew Browne 529f098789 [NFC][DFSan] Update DataFlowSanitizer user docs for -dfsan-conditional-callbacks, added in https://reviews.llvm.org/D116207
Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D117177
2022-01-13 10:05:45 -08:00
Aaron Ballman bf7d9970ba Support the *_WIDTH macros in limits.h and stdint.h
This completes the implementation of
WG14 N2412 (http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2412.pdf),
which standardizes C on a twos complement representation for integer
types. The only work that remained there was to define the correct
macros in the standard headers, which this patch does.
2022-01-13 11:46:34 -05:00
Nick Desaulniers 5c562f62a4 [clang] number labels in asm goto strings after tied inputs
I noticed that the following case would compile in Clang but not GCC:
    void *x(void) {
      void *p = &&foo;
      asm goto ("# %0\n\t# %l1":"+r"(p):::foo);
      foo:;
      return p;
    }

Changing the output template above from %l2 would compile in GCC but not
Clang.

This demonstrates that when using tied outputs (say via the "+r" output
constraint), the hidden inputs occur or are numbered BEFORE the labels,
at least with GCC.

In fact, GCC does denote this in its documentation:
https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Extended-Asm.html#Goto-Labels

> Output operand with constraint modifier ‘+’ is counted as two operands
> because it is considered as one output and one input operand.

For the sake of compatibility, I think it's worthwhile to just make this
change.

It's better to use symbolic names for compatibility (especially now
between released version of Clang that support asm goto with outputs).
ie. %l1 from the above would be %l[foo]. The GCC docs also make this
recommendation.

Also, I cleaned up some cruft in GCCAsmStmt::getNamedOperand. AFAICT,
NumPlusOperands was no longer used, though I couldn't find which commit
didn't clean that up correctly.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98096
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103640
Link: https://gcc.gnu.org/onlinedocs/gcc-11.2.0/gcc/Extended-Asm.html#Goto-Labels

Reviewed By: void

Differential Revision: https://reviews.llvm.org/D115471
2022-01-11 12:09:24 -08:00
Anastasia Stulova dbb8d08637 [SPIR-V] Add linking using spirv-link.
Add support of linking files compiled into SPIR-V objects
using spirv-link.

Command line inteface examples:

clang --target=spirv64 test1.cl test2.cl

clang  --target=spirv64 test1.cl -o test1.o
clang  --target=spirv64 test1.o test2.cl -o test_app.out

This works independently from the SPIR-V generation method
(via an external tool or an internal backend) and applies
to either approach that is being used.

Differential Revision: https://reviews.llvm.org/D116266
2022-01-11 13:11:38 +00:00
Martin Storsjö 50ec1306d0 [clang] Add --start-no-unused-arguments/--end-no-unused-arguments to silence some unused argument warnings
When passing a set of flags to configure defaults for a specific
target (similar to the cmake settings `CLANG_DEFAULT_RTLIB`,
`CLANG_DEFAULT_UNWINDLIB`, `CLANG_DEFAULT_CXX_STDLIB` and
`CLANG_DEFAULT_LINKER`, but without hardcoding them in the binary),
some of the flags may cause warnings (e.g. `-stdlib=` when compiling C
code). Allow requesting selectively ignoring unused arguments among
some of the arguments on the command line, without needing to resort
to `-Qunused-arguments` or `-Wno-unused-command-line-argument`.

Fix up the existing diagnostics.c testcase. It was added in
response to PR12181 to fix handling of
`-Werror=unused-command-line-argument`, but the command line option
in the test (`-fzyzzybalubah`) now triggers "error: unknown argument"
instead of the intended warning. Change it into a linker input
(`-lfoo`) which triggers the intended diagnostic. Extend the
existing test case to check more cases and make sure that it keeps
testing the intended case.

Add testing of the new option to this existing test.

Differential Revision: https://reviews.llvm.org/D116503
2022-01-11 09:22:00 +02:00
Craig Topper db4cb4668b [docs] Fix documentation of -fno-strict-float-cast-overflow after D115804.
Previously this was documented as having the behavior of the
"target's native float-to-int conversion". After D115804, clang
uses saturating FP cast intrinsics which have the same behavior
on all targets.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D116856
2022-01-08 12:12:44 -08:00
Chuanqi Xu bbce75e352 Update Bug report URL to Github Issues
Although we moved to Github Issues. The bug report message refers to
Bugzilla still. This patch tries to update these URLs.

Reviewed By: MaskRay, Quuxplusone, jhenderson, libunwind, libc++

Differential Revision: https://reviews.llvm.org/D116351
2022-01-06 17:33:25 +08:00
Björn Schäpers c2257fe236 [clang-format] Fix SeparateDefinitionBlocks docs and ...
the Style's equality operator.

This amends 6f6f88ffda

Differential Revision: https://reviews.llvm.org/D116557
2022-01-05 12:31:34 +01:00
serge-sans-paille 491984c4e6 Document __builtin_trap and __builtin_debugtrap
Differential Revision: https://reviews.llvm.org/D116598
2022-01-05 03:10:17 -05:00
Fangrui Song d007e66cb6 [docs] Re-generate ClangCommandLineReference.rst 2022-01-04 16:52:24 -08:00
Rajat Bajpai da6b0d0b76 [clang-format] Add an option to add a space between operator overloading and opening parentheses
This change adds an option AfterOverloadedOperator in SpaceBeforeParensOptions to add a space between overloaded operator and opening parentheses in clang-format.

Reviewed By: MyDeveloperDay, curdeius, HazardyKnusperkeks

Differential Revision: https://reviews.llvm.org/D116283
2022-01-04 17:23:23 +01:00
Anastasia Stulova 30ad1742c0 [Docs] Document C++ for OpenCL 2021 support in clang.
Along with the new language mode this commit contains misc
small updates for OpenCL 3 and GitHub issues for OpenCL.

Differential Revision: https://reviews.llvm.org/D116271
2022-01-04 11:18:15 +00:00
ksyx 6f6f88ffda [clang-format] Style to separate definition blocks
This commit resolves GitHub issue #45895 (Bugzilla #46550), to
add or remove empty line between definition blocks including
namespaces, classes, structs, enums and functions.

Reviewed By: MyDeveloperDay, curdeius, HazardyKnusperkeks

Differential Revision: https://reviews.llvm.org/D116314
2022-01-03 15:47:39 -05:00
G. Pery cfe3180742 [clang-format] Add penalty for breaking after '('
My team has a vendetta against lines ending with an open parenthesis, thought it might be useful for others too 😊

Reviewed By: HazardyKnusperkeks, curdeius

Differential Revision: https://reviews.llvm.org/D116170
2022-01-03 21:06:34 +01:00
mydeveloperday b5c84626bb [clang-format] NFC update LLVM overall clang-formatted status
A 1% increase in the number of clang-formatted files.

An additional 235 files have been added to LLVM, and an additional
268 files are now clang-format clean. Raising the overall % to 52%

There are now 8407 files clean out of 15902 (ignoring lit tests)
2022-01-03 13:10:30 +00:00
Zhao Wei Liew b9e173fcd4 [clang-format] Add option to explicitly specify a config file
This diff extends the -style=file option to allow a config file to be specified explicitly. This is useful (for instance) when adding IDE commands to reformat code to a personal style.

Usage: `clang-format -style=file:<path/to/config/file> ...`

Reviewed By: HazardyKnusperkeks, curdeius, MyDeveloperDay, zwliew

Differential Revision: https://reviews.llvm.org/D72326
2022-01-03 11:43:25 +01:00
Marek Kurdej 80e20f9cbd [clang-format] [docs] Fix Mozilla coding style URL.
Fixes https://github.com/llvm/llvm-project/issues/52889.
2022-01-03 09:10:37 +01:00
Jack Andersen 9d37d0ea34 [Support] Expand `<CFGDIR>` as the base directory in configuration files.
Extends response file expansion to recognize `<CFGDIR>` and expand to the
current file's directory. This makes it much easier to author clang config
files rooted in portable, potentially not-installed SDK directories.

A typical use case may be something like the following:

```
# sample_sdk.cfg
--target=sample
-isystem <CFGDIR>/include
-L <CFGDIR>/lib
-T <CFGDIR>/ldscripts/link.ld
```

Reviewed By: sepavloff

Differential Revision: https://reviews.llvm.org/D115604
2021-12-30 13:43:47 -05:00
Anastasia Stulova dc8f9fb196 [Docs] Minor fix in clang user manual 2021-12-24 16:21:56 +00:00
Anastasia Stulova 0045d01af9 [SPIR-V] Add a toolchain for SPIR-V in clang
This patch adds a toolchain (TC) for SPIR-V along with the
following changes in Driver and base ToolChain and Tool.
This is required to provide a mechanism in clang to bypass
SPIR-V backend in LLVM for SPIR-V until it lands in LLVM and
matures.

The SPIR-V code is generated by the SPIRV-LLVM translator tool
named 'llvm-spirv' that is sought in 'PATH'.

The compilation phases/actions should be bound for SPIR-V in
the meantime as following:

    compile -> tools::Clang
    backend -> tools::SPIRV::Translator
    assemble -> tools::SPIRV::Translator

However, Driver’s ToolSelector collapses compile-backend-assemble
and compile-backend sequences to tools::Clang. To prevent this,
added new {use,has}IntegratedBackend properties in ToolChain and
Tool to which the ToolSelector reacts on, and which SPIR-V TC
overrides.

Linking of multiple input files is currently not supported but
can be added separately.

Differential Revision: https://reviews.llvm.org/D112410

Co-authored-by: Henry Linjamäki <henry.linjamaki@parmance.com>
2021-12-23 15:10:09 +00:00
Sami Tolvanen ec2e26eaf6 [Clang] Add __builtin_function_start
Control-Flow Integrity (CFI) replaces references to address-taken
functions with pointers to the CFI jump table. This is a problem
for low-level code, such as operating system kernels, which may
need the address of an actual function body without the jump table
indirection.

This change adds the __builtin_function_start() builtin, which
accepts an argument that can be constant-evaluated to a function,
and returns the address of the function body.

Link: https://github.com/ClangBuiltLinux/linux/issues/1353

Depends on D108478

Reviewed By: pcc, rjmccall

Differential Revision: https://reviews.llvm.org/D108479
2021-12-20 12:55:33 -08:00
Sam McCall af27466c50 Reland "[AST] Add UsingType: a sugar type for types found via UsingDecl"
This reverts commit cc56c66f27.
Fixed a bad assertion, the target of a UsingShadowDecl must not have
*local* qualifiers, but it can be a typedef whose underlying type is qualified.
2021-12-20 18:03:15 +01:00
Sam McCall cc56c66f27 Revert "[AST] Add UsingType: a sugar type for types found via UsingDecl"
This reverts commit e1600db19d.

Breaks sanitizer tests, at least on windows:
https://lab.llvm.org/buildbot/#/builders/127/builds/21592/steps/4/logs/stdio
2021-12-20 17:53:56 +01:00
Sam McCall e1600db19d [AST] Add UsingType: a sugar type for types found via UsingDecl
Currently there's no way to find the UsingDecl that a typeloc found its
underlying type through. Compare to DeclRefExpr::getFoundDecl().

Design decisions:
- a sugar type, as there are many contexts this type of use may appear in
- UsingType is a leaf like TypedefType, the underlying type has no TypeLoc
- not unified with UnresolvedUsingType: a single name is appealing,
  but being sometimes-sugar is often fiddly.
- not unified with TypedefType: the UsingShadowDecl is not a TypedefNameDecl or
  even a TypeDecl, and users think of these differently.
- does not cover other rarer aliases like objc @compatibility_alias,
  in order to be have a concrete API that's easy to understand.
- implicitly desugared by the hasDeclaration ASTMatcher, to avoid
  breaking existing patterns and following the precedent of ElaboratedType.

Scope:
- This does not cover types associated with template names introduced by
  using declarations. A future patch should introduce a sugar TemplateName
  variant for this. (CTAD deduced types fall under this)
- There are enough AST matchers to fix the in-tree clang-tidy tests and
  probably any other matchers, though more may be useful later.

Caveats:
- This changes a fairly common pattern in the AST people may depend on matching.
  Previously, typeLoc(loc(recordType())) matched whether a struct was
  referred to by its original scope or introduced via using-decl.
  Now, the using-decl case is not matched, and needs a separate matcher.
  This is similar to the case of typedefs but nevertheless both adds
  complexity and breaks existing code.

Differential Revision: https://reviews.llvm.org/D114251
2021-12-20 17:15:38 +01:00
Joshua Huels 212e6c9977 [doc] Fix regex in ClangFormatStyleOptions for IncludeCategories
This fixes the regex in ClangFormatStyleOptions for IncludeCategories
to match anything starting with < or starting with | AND followed by
(gtest|gmock|isl|json) then /.

Differential Revision: https://reviews.llvm.org/D115910
2021-12-17 18:46:12 -08:00
Deepak Eachempati d976fb0204 [OpenMP][NFC] update status for 5.1 'fail' atomic extension
Update status for the atomic 'fail' clause to "worked on".

Reviewed By: cchen

Differential Revision: https://reviews.llvm.org/D115901
2021-12-17 11:46:37 -06:00
Nico Weber 770ef94097 Revert "[analyzer][ctu] Fix wrong 'multiple definitions' errors caused by space characters in lookup names when parsing the ctu index file"
This reverts commit 333d66b094.
Breaks tests on macOS, see comments on https://reviews.llvm.org/D102669
2021-12-16 20:46:51 -05:00
Ella Ma 333d66b094 [analyzer][ctu] Fix wrong 'multiple definitions' errors caused by space characters in lookup names when parsing the ctu index file
This error was found when analyzing MySQL with CTU enabled.

When there are space characters in the lookup name, the current
delimiter searching strategy will make the file path wrongly parsed.
And when two lookup names have the same prefix before their first space
characters, a 'multiple definitions' error will be wrongly reported.

e.g. The lookup names for the two lambda exprs in the test case are
`c:@S@G@F@G#@Sa@F@operator int (*)(char)#1` and
`c:@S@G@F@G#@Sa@F@operator bool (*)(char)#1` respectively. And their
prefixes are both `c:@S@G@F@G#@Sa@F@operator` when using the first space
character as the delimiter.

Solving the problem by adding a length for the lookup name, making the
index items in the format of `USR-Length:USR File-Path`.

Reviewed By: steakhal

Differential Revision: https://reviews.llvm.org/D102669
2021-12-16 17:47:59 +01:00
gysit b7f2c108eb [mlir][linalg] Replace LinalgOps.h and LinalgTypes.h by a single header.
After removing the range type, Linalg does not define any type. The revision thus consolidates the LinalgOps.h and LinalgTypes.h into a single Linalg.h header. Additionally, LinalgTypes.cpp is renamed to LinalgDialect.cpp to follow the convention adopted by other dialects such as the tensor dialect.

Depends On D115727

Reviewed By: nicolasvasilache

Differential Revision: https://reviews.llvm.org/D115728
2021-12-15 12:15:03 +00:00
Stephan T. Lavavej 8bd106a891 [NFC] Fix typos in release notes.
Reviewed By: ldionne, Mordante, MaskRay

Differential Revision: https://reviews.llvm.org/D115685
2021-12-14 14:19:42 -08:00
Fangrui Song 1042de9058 [Driver] Add CLANG_DEFAULT_PIE_ON_LINUX to emulate GCC --enable-default-pie
In 2015-05, GCC added the configure option `--enable-default-pie`. When enabled,

* in the absence of -fno-pic/-fpie/-fpic (and their upper-case variants), -fPIE is the default.
* in the absence of -no-pie/-pie/-shared/-static/-static-pie, -pie is the default.

This has been adopted by all(?) major distros.

I think default PIE is the majority in the Linux world, but
--disable-default-pie users is not that uncommon because GCC upstream hasn't
switched the default yet (https://gcc.gnu.org/PR103398).

This patch add CLANG_DEFAULT_PIE_ON_LINUX which allows distros to use default PIE.
The option is justified as its adoption can be very high among Linux distros
to make Clang default match GCC, and is likely a future-new-default, at which
point we will remove CLANG_DEFAULT_PIE_ON_LINUX.
The lit feature `default-pie-on-linux` can be handy to exclude default PIE sensitive tests.

Reviewed By: foutrelis, sylvestre.ledru, thesamesam

Differential Revision: https://reviews.llvm.org/D113372
2021-12-14 10:09:00 -08:00
Andrew Browne 7c004c2bc9 Revert "[asan] Add support for disable_sanitizer_instrumentation attribute"
This reverts commit 2b554920f1.

This change causes tsan test timeout on x86_64-linux-autoconf.

The timeout can be reproduced by:
  git clone https://github.com/llvm/llvm-zorg.git
  BUILDBOT_CLOBBER= BUILDBOT_REVISION=eef8f3f85679c5b1ae725bade1c23ab7bb6b924f llvm-zorg/zorg/buildbot/builders/sanitizers/buildbot_standard.sh
2021-12-10 14:33:38 -08:00
Alexander Potapenko 2b554920f1 [asan] Add support for disable_sanitizer_instrumentation attribute
For ASan this will effectively serve as a synonym for
__attribute__((no_sanitize("address")))

Differential Revision: https://reviews.llvm.org/D114421
2021-12-10 12:17:26 +01:00
Chuanqi Xu 352e36e10d [Coroutines] Remove unused coroutine builtin/intrinsics llvm.coro.param (NFC-ish)
I found that the coroutine intrinsic llvm.coro.param in documentation
(https://llvm.org/docs/Coroutines.html#id101) didn't get used actually
since there isn't lowering codes in LLVM. I also checked the
implementation of libstdc++ and libc++. Both of them didn't use
llvm.coro.param. So I am pretty sure that the llvm.coro.param intrinsic
is unused. I think it would be better t to remove it to avoid possible
misleading understandings.

Note: according to [class.copy.elision]/p1.3, this optimization is
allowed by the C++ language specification. Let's make it someday.

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D115222
2021-12-09 14:40:25 +08:00
Aaron Ballman a18632adc8 Add diagnostic groups for attribute extensions
Some users have a need to control attribute extension diagnostics
independent of other extension diagnostics. Consider something like use
of [[nodiscard]] within C++11:
```
[[nodiscard]]
int f();
```
If compiled with -Wc++17-extensions enabled, this will produce warning:
use of the 'nodiscard' attribute is a C++17 extension. This diagnostic
is correct -- using [[nodiscard]] in C++11 mode is a C++17 extension.
And the behavior of __has_cpp_attribute(nodiscard) is also correct --
we support [[nodiscard]] in C++11 mode as a conforming extension. But
this makes use of -Werror or -pedantic-errors` builds more onerous.

This patch adds diagnostic groups for attribute extensions so that
users can selectively disable attribute extension diagnostics. I
believe this is preferable to requiring users to specify additional
flags because it means -Wc++17-extensions continues to be the way we
enable all C++17-related extension diagnostics. It would be quite easy
for someone to use that flag thinking they're protected from some
portability issues without realizing it skipped attribute extensions if
we went the other way.

This addresses PR33518.
2021-12-07 11:49:53 -05:00
Aaron Ballman 7d5315fc4c Fix Sphinx formatting in release notes 2021-12-07 07:56:40 -05:00
Aaron Ballman 6c75ab5f66 Introduce _BitInt, deprecate _ExtInt
WG14 adopted the _ExtInt feature from Clang for C23, but renamed the
type to be _BitInt. This patch does the vast majority of the work to
rename _ExtInt to _BitInt, which accounts for most of its size. The new
type is exposed in older C modes and all C++ modes as a conforming
extension. However, there are functional changes worth calling out:

* Deprecates _ExtInt with a fix-it to help users migrate to _BitInt.
* Updates the mangling for the type.
* Updates the documentation and adds a release note to warn users what
is going on.
* Adds new diagnostics for use of _BitInt to call out when it's used as
a Clang extension or as a pre-C23 compatibility concern.
* Adds new tests for the new diagnostic behaviors.

I want to call out the ABI break specifically. We do not believe that
this break will cause a significant imposition for early adopters of
the feature, and so this is being done as a full break. If it turns out
there are critical uses where recompilation is not an option for some
reason, we can consider using ABI tags to ease the transition.
2021-12-06 12:52:01 -05:00
Dmitri Gribenko ab31d003e1 [clang][docs][dataflow] Added an introduction to dataflow analysis
This documentation supports the dataflow analysis framework (see "[RFC]
A dataflow analysis framework for Clang AST" on cfe-dev).

Since the implementation of the framework has not been committed yet,
right now the doc describes dataflow analysis in general.

Since this is the first markdown document in clang/docs, I added support
for Markdown to clang/docs/conf.py in the same way as it is done in
llvm/docs.

Reviewed By: xazax.hun

Differential Revision: https://reviews.llvm.org/D114231
2021-12-06 12:16:35 +01:00
Ties Stuij 0fbb17458a [ARM] Implement setjmp BTI placement for PACBTI-M
This patch intends to guard indirect branches performed by longjmp
by inserting BTI instructions after calls to setjmp.

Calls with 'returns-twice' are lowered to a new pseudo-instruction
named t2CALL_BTI that is later expanded to a bundle of {tBL,t2BTI}.

This patch is part of a series that adds support for the PACBTI-M extension of
the Armv8.1-M architecture, as detailed here:

https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/armv8-1-m-pointer-authentication-and-branch-target-identification-extension

The PACBTI-M specification can be found in the Armv8-M Architecture Reference
Manual:

https://developer.arm.com/documentation/ddi0553/latest

The following people contributed to this patch:

- Alexandros Lamprineas
- Ties Stuij

Reviewed By: labrinea

Differential Revision: https://reviews.llvm.org/D112427
2021-12-06 11:07:10 +00:00