I noticed that compiling on Windows with -fno-ms-compatibility had the
side effect of defining __GNUC__, along with __GNUG__, __GXX_RTTI__, and
a number of other macros for GCC compatibility. This is undesirable and
causes Chromium to do things like mix __attribute__ and __declspec,
which doesn't work. We should have a positive language option to enable
GCC compatibility features so that we can experiment with
-fno-ms-compatibility on Windows. This change adds -fgnuc-version= to be
that option.
My issue aside, users have, for a long time, reported that __GNUC__
doesn't match their expectations in one way or another. We have
encouraged users to migrate code away from this macro, but new code
continues to be written assuming a GCC-only environment. There's really
nothing we can do to stop that. By adding this flag, we can allow them
to choose their own adventure with __GNUC__.
This overlaps a bit with the "GNUMode" language option from -std=gnu*.
The gnu language mode tends to enable non-conforming behaviors that we'd
rather not enable by default, but the we want to set things like
__GXX_RTTI__ by default, so I've kept these separate.
Helps address PR42817
Reviewed By: hans, nickdesaulniers, MaskRay
Differential Revision: https://reviews.llvm.org/D68055
llvm-svn: 374449
Summary:
Quote from http://eel.is/c++draft/expr.add#4:
```
4 When an expression J that has integral type is added to or subtracted
from an expression P of pointer type, the result has the type of P.
(4.1) If P evaluates to a null pointer value and J evaluates to 0,
the result is a null pointer value.
(4.2) Otherwise, if P points to an array element i of an array object x with n
elements ([dcl.array]), the expressions P + J and J + P
(where J has the value j) point to the (possibly-hypothetical) array
element i+j of x if 0≤i+j≤n and the expression P - J points to the
(possibly-hypothetical) array element i−j of x if 0≤i−j≤n.
(4.3) Otherwise, the behavior is undefined.
```
Therefore, as per the standard, applying non-zero offset to `nullptr`
(or making non-`nullptr` a `nullptr`, by subtracting pointer's integral value
from the pointer itself) is undefined behavior. (*if* `nullptr` is not defined,
i.e. e.g. `-fno-delete-null-pointer-checks` was *not* specified.)
To make things more fun, in C (6.5.6p8), applying *any* offset to null pointer
is undefined, although Clang front-end pessimizes the code by not lowering
that info, so this UB is "harmless".
Since rL369789 (D66608 `[InstCombine] icmp eq/ne (gep inbounds P, Idx..), null -> icmp eq/ne P, null`)
LLVM middle-end uses those guarantees for transformations.
If the source contains such UB's, said code may now be miscompiled.
Such miscompilations were already observed:
* https://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190826/687838.html
* https://github.com/google/filament/pull/1566
Surprisingly, UBSan does not catch those issues
... until now. This diff teaches UBSan about these UB's.
`getelementpointer inbounds` is a pretty frequent instruction,
so this does have a measurable impact on performance;
I've addressed most of the obvious missing folds (and thus decreased the performance impact by ~5%),
and then re-performed some performance measurements using my [[ https://github.com/darktable-org/rawspeed | RawSpeed ]] benchmark:
(all measurements done with LLVM ToT, the sanitizer never fired.)
* no sanitization vs. existing check: average `+21.62%` slowdown
* existing check vs. check after this patch: average `22.04%` slowdown
* no sanitization vs. this patch: average `48.42%` slowdown
Reviewers: vsk, filcab, rsmith, aaron.ballman, vitalybuka, rjmccall, #sanitizers
Reviewed By: rsmith
Subscribers: kristof.beyls, nickdesaulniers, nikic, ychen, dtzWill, xbolva00, dberris, arphaman, rupprecht, reames, regehr, llvm-commits, cfe-commits
Tags: #clang, #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D67122
llvm-svn: 374293
Summary: The Google C++ and Chromium style guides are broken in the clang-format docs. This patch updates them.
Reviewers: djasper, MyDeveloperDay
Reviewed By: MyDeveloperDay
Subscribers: cfe-commits
Tags: #clang
Patch by: m4tx
Differential Revision: https://reviews.llvm.org/D61256
llvm-svn: 373844
Summary:
This patch makes the `SpacesInSquareBrackets` setting also apply to C++ lambdas with parameters.
Looking through the revision history, it appears support for only array brackets was added, and lambda brackets were ignored. Therefore, I am inclined to think it was simply an omission, rather than a deliberate choice.
See https://bugs.llvm.org/show_bug.cgi?id=17887 and https://reviews.llvm.org/D4944.
Reviewers: MyDeveloperDay, reuk, owenpan
Reviewed By: MyDeveloperDay
Subscribers: cfe-commits
Patch by: mitchell-stellar
Tags: #clang-format, #clang
Differential Revision: https://reviews.llvm.org/D68473
llvm-svn: 373821
Summary:
Change the BraceWrappingFlags' AfterControlStatement from a bool to an enum with three values:
* "Never": This is the default, and does not do any brace wrapping after control statements.
* "MultiLine": This only wraps braces after multi-line control statements (this really only happens when a ColumnLimit is specified).
* "Always": This always wraps braces after control statements.
The first and last options are backwards-compatible with "false" and "true", respectively.
The new "MultiLine" option is useful for when a wrapped control statement's indentation matches the subsequent block's indentation. It makes it easier to see at a glance where the control statement ends and where the block's code begins. For example:
```
if (
foo
&& bar )
{
baz();
}
```
vs.
```
if (
foo
&& bar ) {
baz();
}
```
Short control statements (1 line) do not wrap the brace to the next line, e.g.
```
if (foo) {
bar();
} else {
baz();
}
```
Reviewers: sammccall, owenpan, reuk, MyDeveloperDay, klimek
Reviewed By: MyDeveloperDay
Subscribers: MyDeveloperDay, cfe-commits
Patch By: mitchell-stellar
Tags: #clang-format, #clang, #clang-tools-extra
Differential Revision: https://reviews.llvm.org/D68296
llvm-svn: 373647
Summary:
The historical context:
- clang-format was written when C++11 was current,
and the main language-version concern was >> vs > > template-closers.
An option was added to allow selection of the 03/11 behavior, or auto-detection.
- there was no option to choose simply "latest standard" so anyone who didn't
ever want 03 behavior or auto-detection specified Cpp11.
- In r185149 this option started to affect lexer mode.
- no options were added to cover c++14, as parsing/formatting
didn't change that much. The usage of Cpp11 to mean "latest" became
codified e.g. in r206263
- c++17 added some new constructs. These were mostly backwards-compatible and so
not used in old programs, so having no way to turn them off was OK.
- c++20 added some new constructs and keywords (e.g. co_*) that changed the
meaning of existing programs, and people started to complain that
the c++20 parsing couldn't be turned off.
New plan:
- Default ('Auto') behavior remains unchanged: parse as latest, format
template-closers based on input.
- Add new 'Latest' option that more clearly expresses the intent "use
modern features" that many projects have chosen for their .clang-format files.
- Allow pinning to *any* language version, using the same name as clang -std:
c++03, c++11, c++14 etc. These set precise lexer options, and any
clang-format code depending on these can use a >= check.
- For backwards compatibility, `Cpp11` is an alias for `Latest`, not `c++11`.
This matches the historical documented semantics of this option.
This spelling (and `Cpp03`) are deprecated.
Reviewers: klimek, modocache
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67541
llvm-svn: 373439
And move the relevant information in the doc.
Summary:
Currently, building a large software like Firefox shows
'Use chrome://tracing or Speedscope App (https://www.speedscope.app) for flamegraph visualization'
for each file.
Reviewers: anton-afanasyev
Reviewed By: anton-afanasyev
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D68260
llvm-svn: 373308
This matches how GCC handles it, see e.g. https://gcc.godbolt.org/z/HPplnl.
GCC documents the gnu_inline attribute with "In C++, this attribute does
not depend on extern in any way, but it still requires the inline keyword
to enable its special behavior."
The previous behaviour of gnu_inline in C++, without the extern
keyword, can be traced back to the original commit that added
support for gnu_inline, SVN r69045.
Differential Revision: https://reviews.llvm.org/D67414
llvm-svn: 373078
Summary:
This new Style rule is made as a part of adding support for NetBSD KNF in clang-format. NetBSD have it's own priority of includes which should be followed while formatting NetBSD code. This style sorts the Cpp Includes according to the priorities of NetBSD, as mentioned in the [Style Guide](http://cvsweb.netbsd.org/bsdweb.cgi/src/share/misc/style?rev=HEAD&content-type=text/x-cvsweb-markup)
The working of this Style rule shown below:
**Configuration:**
This revision introduces a new field under IncludeCategories named `SortPriority` which defines the priority of ordering the `#includes` and the `Priority` will define the categories for grouping the `#include blocks`.
Reviewers: cfe-commits, mgorny, christos, MyDeveloperDay
Reviewed By: MyDeveloperDay
Subscribers: lebedev.ri, rdwampler, christos, mgorny, krytarowski
Patch By: Manikishan
Tags: #clang, #clang-format
Differential Revision: https://reviews.llvm.org/D64695
llvm-svn: 372919
Summary: This patch fixes the __is_signed builtin type trait to work with floating point types and enums. Now, the builtin will return true if it is passed a floating point type and false for an enum type.
Reviewers: EricWF, rsmith, erichkeane, craig.topper, efriedma
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67897
llvm-svn: 372621
Commit c15aa241f8 ("[CLANG][BPF] change __builtin_preserve_access_index()
signature") changed the builtin function signature to
PointerT __builtin_preserve_access_index(PointerT ptr)
with a pointer type as the argument/return type, where argument and
return types must be the same.
There is really no reason for this constraint. The builtin just
presented a code region so that IR builtins
__builtin_{array, struct, union}_preserve_access_index
can be applied.
This patch removed the pointer type restriction to permit any
argument type as long as it is permitted by the compiler.
Differential Revision: https://reviews.llvm.org/D67883
llvm-svn: 372516
Summary:
This patch adds support for the Whitesmiths indentation style to clang-format. It’s an update to a patch submitted in 2015 (D6833), but reworks it to use the newer API.
There are still some issues with this patch, primarily around `switch` and `case` support. The added unit test won’t currently pass because of the remaining issues.
Reviewers: mboehme, MyDeveloperDay, djasper
Reviewed By: MyDeveloperDay
Subscribers: krasimir, MyDeveloperDay, echristo, cfe-commits
Patch By: @timwoj (Tim Wojtulewicz)
Tags: #clang
Differential Revision: https://reviews.llvm.org/D67627
llvm-svn: 372497
-Wtautological-overlap-compare and self-comparison from -Wtautological-compare
relay on detecting the same operand in different locations. Previously, each
warning had it's own operand checker. Now, both are merged together into
one function that each can call. The function also now looks through member
access and array accesses.
Differential Revision: https://reviews.llvm.org/D66045
llvm-svn: 372453
Allow this warning to detect a larger number of constant values, including
negative numbers, and handle non-int types better.
Differential Revision: https://reviews.llvm.org/D66044
llvm-svn: 372448
The clang intrinsic __builtin_preserve_access_index() currently
has signature:
const void * __builtin_preserve_access_index(const void * ptr)
This may cause compiler warning when:
- parameter type is "volatile void *" or "const volatile void *", or
- the assign-to type of the intrinsic does not have "const" qualifier.
Further, this signature does not allow dereference of the
builtin result pointer as it is a "const void *" type, which
adds extra step for the user to do type casting.
Let us change the signature to:
PointerT __builtin_preserve_access_index(PointerT ptr)
such that the result and argument types are the same.
With this, directly dereferencing the builtin return value
becomes possible.
Differential Revision: https://reviews.llvm.org/D67734
llvm-svn: 372294
Commit message below, original caused the sphinx build bot to fail, this
one should fix it.
Create UsersManual section entitled 'Controlling Floating Point
Behavior'
Create a new section for documenting the floating point options. Move
all the floating point options into this section, and add new entries
for the floating point options that exist but weren't previously
described in the UsersManual.
Patch By: mibintc
Differential Revision: https://reviews.llvm.org/D67517
llvm-svn: 372229
Behavior'
Create a new section for documenting the floating point options. Move
all the floating point options into this section, and add new entries
for the floating point options that exist but weren't previously
described in the UsersManual.
Patch By: mibintc
Differential Revision: https://reviews.llvm.org/D67517
llvm-svn: 372180
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.
Reviewers: Bigcheese, jfb, rsmith
Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64146
llvm-svn: 371834
Summary:
This option determines whether goto labels are indented according to scope. Setting this option to false causes goto labels to be flushed to the left.
This is mostly copied from [[ http://lists.llvm.org/pipermail/cfe-dev/2015-September/045014.html | this patch ]] submitted by Christian Neukirchen that didn't make its way into trunk.
```
true: false:
int f() { vs. int f() {
if (foo()) { if (foo()) {
label1: label1:
bar(); bar();
} }
label2: label2:
return 1; return 1;
} }
```
Reviewers: klimek, MyDeveloperDay
Reviewed By: MyDeveloperDay
Subscribers: cfe-commits
Tags: #clang, #clang-tools-extra
Patch by: tetsuo-cpp
Differential Revision: https://reviews.llvm.org/D67037
llvm-svn: 371719
AVX512 instructions can cause a frequency drop on these CPUs. This
can negate the performance gains from using wider vectors. Enabling
prefer-vector-width=256 will prevent generation of zmm registers
unless explicit 512 bit operations are used in the original source
code.
I believe gcc and icc both do something similar to this by default.
Differential Revision: https://reviews.llvm.org/D67259
llvm-svn: 371694
As far as I can tell, gcc passes 256/512 bit vectors __int128 in memory. And passes a vector of 1 _int128 in an xmm register. The backend considers <X x i128> as an illegal type and will scalarize any arguments with that type. So we need to coerce the argument types in the frontend to match to avoid the illegal type.
I'm restricting this to change to Linux and NetBSD based on the
how similar ABI changes have been handled in the past.
PS4, FreeBSD, and Darwin are unaffected. I've also added a
new -fclang-abi-compat version to restore the old behavior.
This issue was identified in PR42607. Though even with the types changed, we still seem to be doing some unnecessary stack realignment.
llvm-svn: 371169
This adds a more fine-grained list of OpenMP features with their
implementation status and associated reviews/commits.
Reviewers: kkwli0, ABataev, RaviNarayanaswamy, gtbercea, Hahnfeld
Subscribers: bollu, guansong, jfb, hfinkel, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64375
llvm-svn: 370930
Breaks BUILD_SHARED_LIBS build, introduces cycles in library dependency
graphs. (clangInterp depends on clangAST which depends on clangInterp)
This reverts r370839, which is an yet another recommit of D64146.
llvm-svn: 370874
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.
Reviewers: Bigcheese, jfb, rsmith
Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64146
llvm-svn: 370839
Enables the users to specify an optional flag which would warn for more dead
stores.
Previously it ignored if the dead store happened e.g. in an if condition.
if ((X = generate())) { // dead store to X
}
This patch introduces the `WarnForDeadNestedAssignments` option to the checker,
which is `false` by default - so this change would not affect any previous
users.
I have updated the code, tests and the docs as well. If I missed something, tell
me.
I also ran the analysis on Clang which generated 14 more reports compared to the
unmodified version. All of them seemed reasonable for me.
Related previous patches:
rGf224820b45c6847b91071da8d7ade59f373b96f3
Reviewers: NoQ, krememek, Szelethus, baloghadamsoftware
Reviewed By: Szelethus
Patch by Balázs Benics!
Differential Revision: https://reviews.llvm.org/D66733
llvm-svn: 370767
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.
Reviewers: Bigcheese, jfb, rsmith
Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64146
llvm-svn: 370636
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.
Reviewers: Bigcheese, jfb, rsmith
Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64146
llvm-svn: 370584
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.
Reviewers: Bigcheese, jfb, rsmith
Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64146
llvm-svn: 370531
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.
Reviewers: Bigcheese, jfb, rsmith
Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64146
llvm-svn: 370476
Reid Kleckner