Taking a value and the bitwise-or it with a non-zero constant will always
result in a non-zero value. In a boolean context, this is always true.
if (x | 0x4) {} // always true, intended '&'
This patch creates a new warning group -Wtautological-bitwise-compare for this
warning. It also moves in the existing tautological bitwise comparisons into
this group. A few other changes were needed to the CFGBuilder so that all bool
contexts would be checked. The warnings in -Wtautological-bitwise-compare will
be off by default due to using the CFG.
Fixes: https://bugs.llvm.org/show_bug.cgi?id=42666
Differential Revision: https://reviews.llvm.org/D66046
llvm-svn: 375318
The idea of this page is to document work in progress functionality
and also describe the plan of future development work.
Patch by Anastasia Stulova.
Differential Revision: https://reviews.llvm.org/D69072
llvm-svn: 375111
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
-Deprecate -mmpx and -mno-mpx command line options
-Remove CPUID detection of mpx for -march=native
-Remove MPX from all CPUs
-Remove MPX preprocessor define
I've left the "mpx" string in the backend so we don't fail on old IR, but its not connected to anything.
gcc has also deprecated these command line options. https://www.phoronix.com/scan.php?page=news_item&px=GCC-Patch-To-Drop-MPX
Differential Revision: https://reviews.llvm.org/D66669
llvm-svn: 370393
-dA was in the d_group, which is a preprocessor state dumping group.
However -dA is a debug flag to cause a verbose asm. It was already
implemented to do the same thing as -fverbose-asm, so make it just be an
alias.
llvm-svn: 369926
This fixes some minor grammatical issues I noticed when reading the docs, and changes the recommended feature testing approach to use __has_attribute instead of __has_extension.
llvm-svn: 369687
This broke compiling some ASan tests with never versions of MSVC/the Win
SDK, see https://crbug.com/996675
> MSVC 2017 update 3 (_MSC_VER 1911) enables /Zc:twoPhase by default, and
> so should clang-cl:
> https://docs.microsoft.com/en-us/cpp/build/reference/zc-twophase
>
> clang-cl takes the MSVC version it emulates from the -fmsc-version flag,
> or if that's not passed it tries to check what the installed version of
> MSVC is and uses that, and failing that it uses a default version that's
> currently 1911. So this changes the default if no -fmsc-version flag is
> passed and no installed MSVC is detected. (It also changes the default
> if -fmsc-version is passed or MSVC is detected, and either indicates
> _MSC_VER >= 1911.)
>
> As mentioned in the MSDN article, the Windows SDK header files in
> version 10.0.15063.0 (Creators Update or Redstone 2) and earlier
> versions do not work correctly with /Zc:twoPhase. If you need to use
> these old SDKs with a new clang-cl, explicitly pass /Zc:twoPhase- to get
> the old behavior.
>
> Fixes PR43032.
>
> Differential Revision: https://reviews.llvm.org/D66394
llvm-svn: 369647
MSVC 2017 update 3 (_MSC_VER 1911) enables /Zc:twoPhase by default, and
so should clang-cl:
https://docs.microsoft.com/en-us/cpp/build/reference/zc-twophase
clang-cl takes the MSVC version it emulates from the -fmsc-version flag,
or if that's not passed it tries to check what the installed version of
MSVC is and uses that, and failing that it uses a default version that's
currently 1911. So this changes the default if no -fmsc-version flag is
passed and no installed MSVC is detected. (It also changes the default
if -fmsc-version is passed or MSVC is detected, and either indicates
_MSC_VER >= 1911.)
As mentioned in the MSDN article, the Windows SDK header files in
version 10.0.15063.0 (Creators Update or Redstone 2) and earlier
versions do not work correctly with /Zc:twoPhase. If you need to use
these old SDKs with a new clang-cl, explicitly pass /Zc:twoPhase- to get
the old behavior.
Fixes PR43032.
Differential Revision: https://reviews.llvm.org/D66394
llvm-svn: 369402
Summary:
Previously __has_builtin(__builtin_*) would return false for
__builtin_*s that we modeled as keywords rather than as functions
(because they take type arguments). With this patch, all builtins
that are called with function-call-like syntax return true from
__has_builtin (covering __builtin_* and also the __is_* and __has_* type
traits and the handful of similar builtins without such a prefix).
Update the documentation on __has_builtin and on type traits to match.
While doing this I noticed the type trait documentation was out of date
and incomplete; that's fixed here too.
Reviewers: aaron.ballman
Subscribers: jfb, kristina, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66100
llvm-svn: 368785
Summary:
This change updates `isDerivedFrom` to support Objective-C classes by
converting it to a polymorphic matcher.
Notes:
The matching behavior for Objective-C classes is modeled to match the
behavior of `isDerivedFrom` with C++ classes. To that effect,
`isDerivedFrom` matches aliased types of derived Objective-C classes,
including compatibility aliases. To achieve this, the AST visitor has
been updated to map compatibility aliases to their underlying
Objective-C class.
`isSameOrDerivedFrom` also provides similar behaviors for C++ and
Objective-C classes. The behavior that
`cxxRecordDecl(isSameOrDerivedFrom("X"))` does not match
`class Y {}; typedef Y X;` is mirrored for Objective-C in that
`objcInterfaceDecl(isSameOrDerivedFrom("X"))` does not match either
`@interface Y @end typedef Y X;` or
`@interface Y @end @compatibility_alias X Y;`.
Test Notes:
Ran clang unit tests.
Reviewers: aaron.ballman, jordan_rose, rjmccall, klimek, alexfh, gribozavr
Reviewed By: aaron.ballman, gribozavr
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D60543
llvm-svn: 368632
The default behavior of Clang's indirect function call checker will replace
the address of each CFI-checked function in the output file's symbol table
with the address of a jump table entry which will pass CFI checks. We refer
to this as making the jump table `canonical`. This property allows code that
was not compiled with ``-fsanitize=cfi-icall`` to take a CFI-valid address
of a function, but it comes with a couple of caveats that are especially
relevant for users of cross-DSO CFI:
- There is a performance and code size overhead associated with each
exported function, because each such function must have an associated
jump table entry, which must be emitted even in the common case where the
function is never address-taken anywhere in the program, and must be used
even for direct calls between DSOs, in addition to the PLT overhead.
- There is no good way to take a CFI-valid address of a function written in
assembly or a language not supported by Clang. The reason is that the code
generator would need to insert a jump table in order to form a CFI-valid
address for assembly functions, but there is no way in general for the
code generator to determine the language of the function. This may be
possible with LTO in the intra-DSO case, but in the cross-DSO case the only
information available is the function declaration. One possible solution
is to add a C wrapper for each assembly function, but these wrappers can
present a significant maintenance burden for heavy users of assembly in
addition to adding runtime overhead.
For these reasons, we provide the option of making the jump table non-canonical
with the flag ``-fno-sanitize-cfi-canonical-jump-tables``. When the jump
table is made non-canonical, symbol table entries point directly to the
function body. Any instances of a function's address being taken in C will
be replaced with a jump table address.
This scheme does have its own caveats, however. It does end up breaking
function address equality more aggressively than the default behavior,
especially in cross-DSO mode which normally preserves function address
equality entirely.
Furthermore, it is occasionally necessary for code not compiled with
``-fsanitize=cfi-icall`` to take a function address that is valid
for CFI. For example, this is necessary when a function's address
is taken by assembly code and then called by CFI-checking C code. The
``__attribute__((cfi_jump_table_canonical))`` attribute may be used to make
the jump table entry of a specific function canonical so that the external
code will end up taking a address for the function that will pass CFI checks.
Fixes PR41972.
Differential Revision: https://reviews.llvm.org/D65629
llvm-svn: 368495
Summary:
The `ExprWithCleanups` node is added to the AST along with the elidable
CXXConstructExpr. If it is the outermost node of the node being matched, ignore
it as well.
Reviewers: gribozavr
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D65944
llvm-svn: 368319
Summary:
This document includes the description of the ASTImporter from the user/client
perspective.
A subsequent patch will describe the development internals.
Reviewers: a_sidorin, shafik, gamesh411, balazske, a.sidorin
Subscribers: rnkovacs, dkrupp, arphaman, Szelethus, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D65573
llvm-svn: 368009
Summary: The minimum compilers support all have alignas, and we don't use LLVM_ALIGNAS anywhere anymore. This also removes an MSVC diagnostic which, according to the comment above, isn't relevant anymore.
Reviewers: rnk
Subscribers: mgorny, jkorous, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65458
llvm-svn: 367383
Rename lang mode flag to -cl-std=clc++/-cl-std=CLC++
or -std=clc++/-std=CLC++.
This aligns with OpenCL C conversion and removes ambiguity
with OpenCL C++.
Differential Revision: https://reviews.llvm.org/D65102
llvm-svn: 367008
This adds a new vectorize predication loop hint:
#pragma clang loop vectorize_predicate(enable)
that can be used to indicate to the vectoriser that all (load/store)
instructions should be predicated (masked). This allows, for example, folding
of the remainder loop into the main loop.
This patch will be followed up with D64916 and D65197. The former is a
refactoring in the loopvectorizer and the groundwork to make tail loop folding
a more general concept, and in the latter the actual tail loop folding
transformation will be implemented.
Differential Revision: https://reviews.llvm.org/D64744
llvm-svn: 366989
Summary:
Move `-ftime-trace-granularity` option to frontend options. Without patch
this option is showed up in the help for any tool that links libSupport.
Reviewers: sammccall
Subscribers: hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65202
llvm-svn: 366911
Added documentation of C++ for OpenCL mode into Clang
User Manual and Language Extensions document.
Differential Revision: https://reviews.llvm.org/D64418
llvm-svn: 366351
i.e., recent 5745eccef54ddd3caca278d1d292a88b2281528b:
* Bump the function_type_mismatch handler version, as its signature has changed.
* The function_type_mismatch handler can return successfully now, so
SanitizerKind::Function must be AlwaysRecoverable (like for
SanitizerKind::Vptr).
* But the minimal runtime would still unconditionally treat a call to the
function_type_mismatch handler as failure, so disallow -fsanitize=function in
combination with -fsanitize-minimal-runtime (like it was already done for
-fsanitize=vptr).
* Add tests.
Differential Revision: https://reviews.llvm.org/D61479
llvm-svn: 366186
Some targets such as Python 2.7.16 still use VERSION in
their builds. Without VERSION defined, the source code
has syntax errors.
Reverting as it will probably break many other things.
Noticed by Sterling Augustine
llvm-svn: 365992
Summary:
It has been introduced in 2011 for gcc compat:
ad1a4c6e89
it is probably time to remove it
Reviewers: rnk, dexonsmith
Reviewed By: rnk
Subscribers: dschuff, aheejin, fedor.sergeev, arphaman, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64062
llvm-svn: 365962
This flag is analoguous to other flags like -nostdlib or -nolibc
and could be used to disable linking of profile runtime library.
This is useful in certain environments like kernel, where profile
instrumentation is still desirable, but we cannot use the standard
runtime library.
llvm-svn: 365808
Summary:
Header links should have some standard form so clang tidy
docs can easily reference them. The form is as follows.
Start with the analyzer full name including packages.
Replace all periods with dashes and lowercase everything.
Ex: core.CallAndMessage -> core-callandmessage
Reviewers: JonasToth, aaron.ballman, NoQ, Szelethus
Reviewed By: aaron.ballman, Szelethus
Subscribers: nickdesaulniers, lebedev.ri, baloghadamsoftware, mgrang, a.sidorin, Szelethus, jfb, donat.nagy, dkrupp, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D64543
llvm-svn: 365797
Richard Trieu