When doing overload resolution, we have to check that candidates' parameter types are equal before trying to find a better candidate through checking which candidate is more constrained.
This revision adds this missing check and makes us diagnose those cases as ambiguous calls when the types are not equal.
Fixes GitHub issue https://github.com/llvm/llvm-project/issues/53640
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D123182
By default -fsanitize=address already compiles with this check,
why not use it.
For compatibly it can be disabled with env ASAN_OPTIONS=detect_stack_use_after_return=0.
Reviewed By: eugenis, kda, #sanitizers, hans
Differential Revision: https://reviews.llvm.org/D124057
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.
This reverts commit 69dd89fdcb.
This reverts commit 04000c2f92.
The current states breaks libstdc++ usage (https://reviews.llvm.org/D119136#3455423).
The fixup has been reverted as it caused other valid code to be disallowed.
I think we should start from the clean state by reverting all relevant commits.
WG14 has elected to remove support for K&R C functions in C2x. The
feature was introduced into C89 already deprecated, so after this long
of a deprecation period, the committee has made an empty parameter list
mean the same thing in C as it means in C++: the function accepts no
arguments exactly as if the function were written with (void) as the
parameter list.
This patch implements WG14 N2841 No function declarators without
prototypes (http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2841.htm)
and WG14 N2432 Remove support for function definitions with identifier
lists (http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2432.pdf).
It also adds The -fno-knr-functions command line option to opt into
this behavior in other language modes.
Differential Revision: https://reviews.llvm.org/D123955
C89 had a questionable feature where the compiler would implicitly
declare a function that the user called but was never previously
declared. The resulting function would be globally declared as
extern int func(); -- a function without a prototype which accepts zero
or more arguments.
C99 removed support for this questionable feature due to severe
security concerns. However, there was no deprecation period; C89 had
the feature, C99 didn't. So Clang (and GCC) both supported the
functionality as an extension in C99 and later modes.
C2x no longer supports that function signature as it now requires all
functions to have a prototype, and given the known security issues with
the feature, continuing to support it as an extension is not tenable.
This patch changes the diagnostic behavior for the
-Wimplicit-function-declaration warning group depending on the language
mode in effect. We continue to warn by default in C89 mode (due to the
feature being dangerous to use). However, because this feature will not
be supported in C2x mode, we've diagnosed it as being invalid for so
long, the security concerns with the feature, and the trivial
workaround for users (declare the function), we now default the
extension warning to an error in C99-C17 mode. This still gives users
an easy workaround if they are extensively using the extension in those
modes (they can disable the warning or use -Wno-error to downgrade the
error), but the new diagnostic makes it more clear that this feature is
not supported and should be avoided. In C2x mode, we no longer allow an
implicit function to be defined and treat the situation the same as any
other lookup failure.
Differential Revision: https://reviews.llvm.org/D122983
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.
New checks rely on 2 invariants:
1) For frontend instrumentation, MD_prof branch_weights will always be
populated before llvm.expect intrinsics are lowered.
2) for IR and sample profiling, llvm.expect intrinsics will always be
lowered before branch_weights are populated from the IR profiles.
These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.
Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D115907
Summary:
This patch removes the OpenMP sections in the release notes. These will
be filled once the release is close and implementations are finalized.
When doing overload resolution, we have to check that candidates' parameter types are equal before trying to find a better candidate through checking which candidate is more constrained.
This revision adds this missing check and makes us diagnose those cases as ambiguous calls when the types are not equal.
Fixes GitHub issue https://github.com/llvm/llvm-project/issues/53640
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D123182
Partially implement the proposed resolution to CWG2569.
D119136 broke some libstdc++ code, as P2036R3, implemented as a DR to
C++11 made ill-formed some previously valid and innocuous code.
We resolve this issue to allow decltype(x) - but not decltype((x)
to appear in the parameter list of a lambda that capture x by copy.
Unlike CWG2569, we do not extend that special treatment to
sizeof/noexcept yet, as the resolution has not been approved yet
and keeping the review small allows a quicker fix of impacted code.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D123909
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
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
Implement P2036R3.
Captured variables by copy (explicitely or not), are deduced
correctly at the point we know whether the lambda is mutable,
and ill-formed before that.
Up until now, the entire lambda declaration up to the start of the body would be parsed in the parent scope, such that capture would not be available to look up.
The scoping is changed to have an outer lambda scope, followed by the lambda prototype and body.
The lambda scope is necessary because there may be a template scope between the start of the lambda (to which we want to attach the captured variable) and the prototype scope.
We also need to introduce a declaration context to attach the captured variable to (and several parts of clang assume captures are handled from the call operator context), before we know the type of the call operator.
The order of operations is as follow:
* Parse the init capture in the lambda's parent scope
* Introduce a lambda scope
* Create the lambda class and call operator
* Add the init captures to the call operator context and the lambda scope. But the variables are not capured yet (because we don't know their type).
Instead, explicit captures are stored in a temporary map that conserves the order of capture (for the purpose of having a stable order in the ast dumps).
* A flag is set on LambdaScopeInfo to indicate that we have not yet injected the captures.
* The parameters are parsed (in the parent context, as lambda mangling recurses in the parent context, we couldn't mangle a lambda that is attached to the context of a lambda whose type is not yet known).
* The lambda qualifiers are parsed, at this point We can switch (for the second time) inside the lambda context, unset the flag indicating that we have not parsed the lambda qualifiers,
record the lambda is mutable and capture the explicit variables.
* We can parse the rest of the lambda type, transform the lambda and call operator's types and also transform the call operator to a template function decl where necessary.
At this point, both captures and parameters can be injected in the body's scope. When trying to capture an implicit variable, if we are before the qualifiers of a lambda, we need to remember that the variables are still in the parent's context (rather than in the call operator's).
Reviewed By: aaron.ballman, #clang-language-wg, ChuanqiXu
Differential Revision: https://reviews.llvm.org/D119136
Clang should no longer incorrectly diagnose a variable declaration inside of a
lambda expression that shares the name of a variable in a containing
if/while/for/switch init statement as a redeclaration.
After this patch, clang is supposed to accept code below:
void foo() {
for (int x = [] { int x = 0; return x; }(); ;) ;
}
Fixes https://github.com/llvm/llvm-project/issues/54913
Differential Revision: https://reviews.llvm.org/D123840
This catches places where a function without a prototype is
accidentally used, potentially passing an incorrect number of
arguments, and is a follow-up to the work done in
https://reviews.llvm.org/D122895 and described in the RFC
(https://discourse.llvm.org/t/rfc-enabling-wstrict-prototypes-by-default-in-c).
The diagnostic is grouped under the new -Wdeprecated-non-prototypes
warning group and is enabled by default.
The diagnostic is disabled if the function being called was implicitly
declared (the user already gets an on-by-default warning about the
creation of the implicit function declaration, so no need to warn them
twice on the same line). Additionally, the diagnostic is disabled if
the declaration of the function without a prototype was in a location
where the user explicitly disabled deprecation warnings for functions
without prototypes (this allows the provider of the API a way to
disable the diagnostic at call sites because the lack of prototype is
intentional).
Implement P2036R3.
Captured variables by copy (explicitely or not), are deduced
correctly at the point we know whether the lambda is mutable,
and ill-formed before that.
Up until now, the entire lambda declaration up to the start
of the body would be parsed in the parent scope, such that
captures would not be available to look up.
The scoping is changed to have an outer lambda scope,
followed by the lambda prototype and body.
The lambda scope is necessary because there may be a template scope
between the start of the lambda (to which we want to attach
the captured variable) and the prototype scope.
We also need to introduce a declaration context to attach the captured
variable to (and several parts of clang assume captures are handled from
the call operator context), before we know the type of the call operator.
The order of operations is as follow:
* Parse the init capture in the lambda's parent scope
* Introduce a lambda scope
* Create the lambda class and call operator
* Add the init captures to the call operator context and the lambda scope.
But the variables are not capured yet (because we don't know their type).
Instead, explicit captures are stored in a temporary map that
conserves the order of capture (for the purpose of having a stable order in the ast dumps).
* A flag is set on LambdaScopeInfo to indicate that we have not yet injected the captures.
* The parameters are parsed (in the parent context, as lambda mangling recurses in the parent context,
we couldn't mangle a lambda that is attached to the context of a lambda whose type is not yet known).
* The lambda qualifiers are parsed, at this point,
we can switch (for the second time) inside the lambda context,
unset the flag indicating that we have not parsed the lambda qualifiers,
record the lambda is mutable and capture the explicit variables.
* We can parse the rest of the lambda type, transform the lambda and call operator's types and also
transform the call operator to a template function decl where necessary.
At this point, both captures and parameters can be injected in the body's scope.
When trying to capture an implicit variable, if we are before the qualifiers of a lambda,
we need to remember that the variables are still in the parent's context (rather than in the call operator's).
This is a recommit of adff142dc2 after a fix in d8d793f29b
Reviewed By: aaron.ballman, #clang-language-wg, ChuanqiXu
Differential Revision: https://reviews.llvm.org/D119136
This reverts commit adff142dc2.
This broke clang bootstrap: it made existing C++ code in LLVM invalid:
llvm/include/llvm/CodeGen/LiveInterval.h:630:53: error: captured variable 'Idx' cannot appear here
[=](std::remove_reference_t<decltype(*Idx)> V,
^
Implement P2036R3.
Captured variables by copy (explicitely or not), are deduced
correctly at the point we know whether the lambda is mutable,
and ill-formed before that.
Up until now, the entire lambda declaration up to the start of the body would be parsed in the parent scope, such that capture would not be available to look up.
The scoping is changed to have an outer lambda scope, followed by the lambda prototype and body.
The lambda scope is necessary because there may be a template scope between the start of the lambda (to which we want to attach the captured variable) and the prototype scope.
We also need to introduce a declaration context to attach the captured variable to (and several parts of clang assume captures are handled from the call operator context), before we know the type of the call operator.
The order of operations is as follow:
* Parse the init capture in the lambda's parent scope
* Introduce a lambda scope
* Create the lambda class and call operator
* Add the init captures to the call operator context and the lambda scope. But the variables are not capured yet (because we don't know their type).
Instead, explicit captures are stored in a temporary map that conserves the order of capture (for the purpose of having a stable order in the ast dumps).
* A flag is set on LambdaScopeInfo to indicate that we have not yet injected the captures.
* The parameters are parsed (in the parent context, as lambda mangling recurses in the parent context, we couldn't mangle a lambda that is attached to the context of a lambda whose type is not yet known).
* The lambda qualifiers are parsed, at this point We can switch (for the second time) inside the lambda context, unset the flag indicating that we have not parsed the lambda qualifiers,
record the lambda is mutable and capture the explicit variables.
* We can parse the rest of the lambda type, transform the lambda and call operator's types and also transform the call operator to a template function decl where necessary.
At this point, both captures and parameters can be injected in the body's scope. When trying to capture an implicit variable, if we are before the qualifiers of a lambda, we need to remember that the variables are still in the parent's context (rather than in the call operator's).
Reviewed By: aaron.ballman, #clang-language-wg, ChuanqiXu
Differential Revision: https://reviews.llvm.org/D119136
We did not implement C99 6.7.5.3p15 fully in that we missed the rule
for compatible function types where a prior declaration has a prototype
and a subsequent definition (not just declaration) has an empty
identifier list or an identifier list with a mismatch in parameter
arity. This addresses that situation by issuing an error on code like:
void f(int);
void f() {} // type conflicts with previous declaration
(Note: we already diagnose the other type conflict situations
appropriately, this was the only situation we hadn't covered that I
could find.)
According to CWG 1394 and C++20 [dcl.fct.def.general]p2,
Clang should not diagnose incomplete types if function body is "= delete;".
For example:
```
struct Incomplete;
Incomplete f(Incomplete) = delete; // well-formed
```
Also close https://github.com/llvm/llvm-project/issues/52802
Differential Revision: https://reviews.llvm.org/D122981
The Randstruct feature is a compile-time hardening technique that
randomizes the field layout for designated structures of a code base.
Admittedly, this is mostly useful for closed-source releases of code,
since the randomization seed would need to be available for public and
open source applications.
Why implement it? This patch set enhances Clang’s feature parity with
that of GCC which already has the Randstruct feature. It's used by the
Linux kernel in certain structures to help thwart attacks that depend on
structure layouts in memory.
This patch set is a from-scratch reimplementation of the Randstruct
feature that was originally ported to GCC. The patches for the GCC
implementation can be found here:
https://www.openwall.com/lists/kernel-hardening/2017/04/06/14
Link: https://lists.llvm.org/pipermail/cfe-dev/2019-March/061607.html
Co-authored-by: Cole Nixon <nixontcole@gmail.com>
Co-authored-by: Connor Kuehl <cipkuehl@gmail.com>
Co-authored-by: James Foster <jafosterja@gmail.com>
Co-authored-by: Jeff Takahashi <jeffrey.takahashi@gmail.com>
Co-authored-by: Jordan Cantrell <jordan.cantrell@mail.com>
Co-authored-by: Nikk Forbus <nicholas.forbus@gmail.com>
Co-authored-by: Tim Pugh <nwtpugh@gmail.com>
Co-authored-by: Bill Wendling <isanbard@gmail.com>
Signed-off-by: Bill Wendling <isanbard@gmail.com>
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D121556
(With C++ exceptions, `clang++ --target=mips64{,el}-linux-gnu -fpie -pie
-fuse-ld=lld` has link errors (lld does not implement some strange R_MIPS_64
.eh_frame handling in GNU ld). However, sanitizer-x86_64-linux-qemu used this to
build ScudoUnitTests. Pined ScudoUnitTests to -no-pie.)
Default the option introduced in D113372 to ON to match all(?) major Linux
distros. This matches GCC and improves consistency with Android and linux-musl
which always default to PIE.
Note: CLANG_DEFAULT_PIE_ON_LINUX may be removed in the future.
Differential Revision: https://reviews.llvm.org/D120305
This reverts commit 3f0587d0c6.
Not all tests pass after a few rounds of fixes.
I spot one failure that std::shuffle (potentially different results with
different STL implementations) was misused and replaced it with llvm::shuffle,
but there appears to be another failure in a Windows build.
The latest failure is reported on https://reviews.llvm.org/D121556#3440383
Functions without prototypes in C (also known as K&R C functions) were
introduced into C89 as a deprecated feature and C2x is now reclaiming
that syntax space with different semantics. However, Clang's
-Wstrict-prototypes diagnostic is off-by-default (even in pedantic
mode) and does not suffice to warn users about issues in their code.
This patch changes the behavior of -Wstrict-prototypes to only diagnose
declarations and definitions which are not going to change behavior in
C2x mode, and enables the diagnostic in -pedantic mode. The diagnostic
is now specifically about the fact that the feature is deprecated.
It also adds -Wdeprecated-non-prototype, which is grouped under
-Wstrict-prototypes and diagnoses declarations or definitions which
will change behavior in C2x mode. This diagnostic is enabled by default
because the risk is higher for the user to continue to use the
deprecated feature.
Differential Revision: https://reviews.llvm.org/D122895
The Randstruct feature is a compile-time hardening technique that
randomizes the field layout for designated structures of a code base.
Admittedly, this is mostly useful for closed-source releases of code,
since the randomization seed would need to be available for public and
open source applications.
Why implement it? This patch set enhances Clang’s feature parity with
that of GCC which already has the Randstruct feature. It's used by the
Linux kernel in certain structures to help thwart attacks that depend on
structure layouts in memory.
This patch set is a from-scratch reimplementation of the Randstruct
feature that was originally ported to GCC. The patches for the GCC
implementation can be found here:
https://www.openwall.com/lists/kernel-hardening/2017/04/06/14
Link: https://lists.llvm.org/pipermail/cfe-dev/2019-March/061607.html
Co-authored-by: Cole Nixon <nixontcole@gmail.com>
Co-authored-by: Connor Kuehl <cipkuehl@gmail.com>
Co-authored-by: James Foster <jafosterja@gmail.com>
Co-authored-by: Jeff Takahashi <jeffrey.takahashi@gmail.com>
Co-authored-by: Jordan Cantrell <jordan.cantrell@mail.com>
Co-authored-by: Nikk Forbus <nicholas.forbus@gmail.com>
Co-authored-by: Tim Pugh <nwtpugh@gmail.com>
Co-authored-by: Bill Wendling <isanbard@gmail.com>
Signed-off-by: Bill Wendling <isanbard@gmail.com>
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D121556
(The upgrade of the ppc64le bot and D121257 have fixed compiler-rt failures. Tested by nemanjai.)
Default the option introduced in D113372 to ON to match all(?) major Linux
distros. This matches GCC and improves consistency with Android and linux-musl
which always default to PIE.
Note: CLANG_DEFAULT_PIE_ON_LINUX may be removed in the future.
Differential Revision: https://reviews.llvm.org/D120305
Note that the mangling has changed and the demangler's learnt a new
trick. Obviously dependent upon the mangler and demangler patches.
Reviewed By: bruno
Differential Revision: https://reviews.llvm.org/D123141
As statement expression makes no sense in the default argument,
this patch tries to disable it in the all cases.
Please note that the statement expression is a GNU extension, which
means that Clang should be consistent with GCC. However, there's no
response from GCC devs since we have raised the issue for several weeks.
In this case, I think we can disallow statement expressions as a default
parameter in general for now, and relax the restriction if GCC folks
decide to retain the feature for functions but not lambdas in the
future.
Related discussion: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104765
Fixes https://github.com/llvm/llvm-project/issues/53488
Differential Revision: https://reviews.llvm.org/D119609
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.
New checks rely on 2 invariants:
1) For frontend instrumentation, MD_prof branch_weights will always be
populated before llvm.expect intrinsics are lowered.
2) for IR and sample profiling, llvm.expect intrinsics will always be
lowered before branch_weights are populated from the IR profiles.
These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.
Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D115907
Beautify dump format, add indent for nested struct and struct members, also fix test cases in dump-struct-builtin.c
for example:
struct:
```
struct A {
int a;
struct B {
int b;
struct C {
struct D {
int d;
union E {
int x;
int y;
} e;
} d;
int c;
} c;
} b;
};
```
Before:
```
struct A {
int a = 0
struct B {
int b = 0
struct C {
struct D {
int d = 0
union E {
int x = 0
int y = 0
}
}
int c = 0
}
}
}
```
After:
```
struct A {
int a = 0
struct B {
int b = 0
struct C {
struct D {
int d = 0
union E {
int x = 0
int y = 0
}
}
int c = 0
}
}
}
```
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D122704
Remove anonymous tag locations, powered by 'PrintingPolicy',
@aaron.ballman once suggested removing this extra information in
https://reviews.llvm.org/D122248
struct:
struct S {
int a;
struct /* Anonymous*/ {
int x;
} b;
int c;
};
Before:
struct S {
int a = 0
struct S::(unnamed at ./builtin_dump_struct.c:20:3) {
int x = 0
}
int c = 0
}
After:
struct S {
int a = 0
struct S::(unnamed) {
int x = 0
}
int c = 0
}
Differntial Revision: https://reviews.llvm.org/D122670
Member access for an atomic structure or union is unconditional
undefined behavior (C11 6.5.2.3p5). However, we would issue a confusing
error message about the base expression not being a structure or union
type.
GCC issues a warning for this case. Clang now warns as well, but the
warning is defaulted to an error because the actual access is still
unsafe.
This fixes Issue 54563.
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.
New checks rely on 2 invariants:
1) For frontend instrumentation, MD_prof branch_weights will always be
populated before llvm.expect intrinsics are lowered.
2) for IR and sample profiling, llvm.expect intrinsics will always be
lowered before branch_weights are populated from the IR profiles.
These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.
Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.
Reviewed By: tejohnson
Differential Revision: https://reviews.llvm.org/D115907
This builtin returns the address of a global instance of the
`std::source_location::__impl` type, which must be defined (with an
appropriate shape) before calling the builtin.
It will be used to implement std::source_location in libc++ in a
future change. The builtin is compatible with GCC's implementation,
and libstdc++'s usage. An intentional divergence is that GCC declares
the builtin's return type to be `const void*` (for
ease-of-implementation reasons), while Clang uses the actual type,
`const std::source_location::__impl*`.
In order to support this new functionality, I've also added a new
'UnnamedGlobalConstantDecl'. This artificial Decl is modeled after
MSGuidDecl, and is used to represent a generic concept of an lvalue
constant with global scope, deduplicated by its value. It's possible
that MSGuidDecl itself, or some of the other similar sorts of things
in Clang might be able to be refactored onto this more-generic
concept, but there's enough special-case weirdness in MSGuidDecl that
I gave up attempting to share code there, at least for now.
Finally, for compatibility with libstdc++'s <source_location> header,
I've added a second exception to the "cannot cast from void* to T* in
constant evaluation" rule. This seems a bit distasteful, but feels
like the best available option.
Reviewers: aaron.ballman, erichkeane
Differential Revision: https://reviews.llvm.org/D120159
Previously, we would instantiate the UDL by marking the function as
referenced and potentially binding to a temporary; this skipped
transforming the call when the UDL was dependent on a template
parameter.
Now, we defer all the work to instantiating the call expression for the
UDL. This ensures that constant evaluation occurs at compile time
rather than deferring until runtime.
Fixes Issue 54578.
In C, assignment expressions result in an rvalue whose type is the type
of the lhs of the assignment after it undergoes lvalue to rvalue
conversion. lvalue to rvalue conversion in C strips all qualifiers
including _Atomic.
We used getUnqualifiedType() which does not strip the _Atomic qualifier
when we should have used getAtomicUnqualifiedType(). This corrects the
usage and adds some comments to getUnqualifiedType() to make it more
clear that it does not strip _Atomic and that's on purpose (see C11
6.2.5p27).
This addresses Issue 48742.
Update `WeakUndeclaredIdentifiers` to hold a collection of weak
aliases per identifier instead of only one.
This also allows the "used" state to be removed from `WeakInfo`
because it is really only there as an alternative to removing
processed map entries, and we can represent that using an empty set
now. The serialization code is updated for the removal of the field.
Additionally, a PCH test is added for the new functionality.
The records are grouped by the "target" identifier, which was already
being used as a key for lookup purposes. We also store only one record
per alias name; combined, this means that diagnostics are grouped by
the "target" and limited to one per alias (which should be acceptable).
Fixes PR28611.
Fixesllvm/llvm-project#28985.
Reviewed By: aaron.ballman, cebowleratibm
Differential Revision: https://reviews.llvm.org/D121927
Co-authored-by: Rachel Craik <rcraik@ca.ibm.com>
Co-authored-by: Jamie Schmeiser <schmeise@ca.ibm.com>
Fix clang crash and add bitfield support in __builtin_dump_struct.
In clang13.0.x, a struct with three or more members and a bitfield at
the same time will cause a crash. In clang15.x, as long as the struct
has one bitfield, it will cause a crash in clang.
Open issue: https://github.com/llvm/llvm-project/issues/54462
Differential Revision: https://reviews.llvm.org/D122248
Currently, Clang handles some qualifiers correctly for __auto_type, but
it does not handle the restrict or _Atomic qualifiers in the same way
that GCC does. This patch handles those qualifiers so that they attach
to the deduced type the same as const and volatile already do.
This fixes https://github.com/llvm/llvm-project/issues/53652
This reverts commit edb7ba714a.
This changes BLR_BTI to take variable_ops meaning that we can accept
a register or a label. The pattern still expects one argument so we'll
never get more than one. Then later we can check the type of the operand
to choose BL or BLR to emit.
(this is what BLR_RVMARKER does but I missed this detail of it first time around)
Also require NoSLSBLRMitigation which I missed in the first version.
Some implementations of setjmp will end with a br instead of a ret.
This means that the next instruction after a call to setjmp must be
a "bti j" (j for jump) to make this work when branch target identification
is enabled.
The BTI extension was added in armv8.5-a but the bti instruction is in the
hint space. This means we can emit it for any architecture version as long
as branch target enforcement flags are passed.
The starting point for the hint number is 32 then call adds 2, jump adds 4.
Hence "hint #36" for a "bti j" (and "hint #34" for the "bti c" you see
at the start of functions).
The existing Arm command line option -mno-bti-at-return-twice has been
applied to AArch64 as well.
Support is added to SelectionDAG Isel and GlobalIsel. FastIsel will
defer to SelectionDAG.
Based on the change done for M profile Arm in https://reviews.llvm.org/D112427Fixes#48888
Reviewed By: danielkiss
Differential Revision: https://reviews.llvm.org/D121707
Allow goto, labelled statements as well as `static`, `thread_local`, and
non-literal variables in `constexpr` functions.
As specified. for all of the above (except labelled statements) constant
evaluation of the construct still fails.
For `constexpr` bodies, the proposal is implemented with diagnostics as
a language extension in older language modes. For determination of
whether a lambda body satisfies the requirements for a constexpr
function, the proposal is implemented only in C++2b mode to retain the
semantics of older modes for programs conforming to them.
Reviewed By: aaron.ballman, hubert.reinterpretcast, erichkeane
Differential Revision: https://reviews.llvm.org/D111400
These diagnostics were added to a diagnostic group, but that diagnostic
group was not under -Wgnu. I've now split them into their own
diagnostic group that is added both to the original group (so user's
currently opting in or out of these should not see a change) and under
the -Wgnu group so that -Wno-gnu can be used to disable all GNU
extension diagnostics. This fixes Issue 54444.
This adds support for multiple attributes in `#pragma clang attribute push`, for example:
```
```
or
```
```
Related attributes can now be applied with a single pragma, which makes it harder for developers to make an accidental error later when editing the code.
rdar://78269653
Differential Revision: https://reviews.llvm.org/D121283
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.
New checks rely on 2 invariants:
1) For frontend instrumentation, MD_prof branch_weights will always be
populated before llvm.expect intrinsics are lowered.
2) for IR and sample profiling, llvm.expect intrinsics will always be
lowered before branch_weights are populated from the IR profiles.
These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.
Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.
Differential Revision: https://reviews.llvm.org/D115907
If we are equality comparing an FP literal with a value cast from a type
where the literal can't be represented, that's known true or false and
probably a programmer error.
Fixes issue #54222.
https://github.com/llvm/llvm-project/issues/54222
Note - I added the optimizer change with:
9397bdc67e
...and as discussed in the post-commit comments, that transform might be
too dangerous without this warning in place, so it was reverted to allow
this change first.
Differential Revision: https://reviews.llvm.org/D121306
GCC supports:
- `namespace <gnu attributes> identifier`
- `namespace identifier <gnu attributes>`
But clang supports only `namespace identifier <gnu attributes>` and diagnostics for `namespace <gnu attributes> identifier` case looks unclear:
Code:
```
namespace __attribute__((visibility("hidden"))) A
{
}
```
Diags:
```
test.cpp:1:49: error: expected identifier or '{'
namespace __attribute__((visibility("hidden"))) A
^
test.cpp:1:49: error: C++ requires a type specifier for all declarations
test.cpp:3:2: error: expected ';' after top level declarator
}
```
This patch adds support for `namespace <gnu attributes> identifier` and also forbids gnu attributes for nested namespaces (this already done for C++ attributes).
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D121245
WG14 adopted N2775 (http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2775.pdf)
at our Feb 2022 meeting. This paper adds a literal suffix for
bit-precise types that automatically sizes the bit-precise type to be
the smallest possible legal _BitInt type that can represent the literal
value. The suffix chosen is wb (for a signed bit-precise type) which
can be combined with the u suffix (for an unsigned bit-precise type).
The preprocessor continues to operate as-if all integer types were
intmax_t/uintmax_t, including bit-precise integer types. It is a
constraint violation if the bit-precise literal is too large to fit
within that type in the context of the preprocessor (when still using
a pp-number preprocessing token), but it is not a constraint violation
in other circumstances. This allows you to make bit-precise integer
literals that are wider than what the preprocessor currently supports
in order to initialize variables, etc.
We were not creating an evaluation context for the TU scope, so we
never popped an evaluation context for it. Popping the evaluation
context triggers a number of diagnostics, including warnings about
immediate invocations that we were previously missing.
Note: I think we have an additional issue that we should solve, but not
as part of this patch. I don't think Clang is properly modeling static
initialization as happening before constant expression evaluation. I
think structure members members are zero initialized per
http://eel.is/c++draft/basic.start.static#1,
https://eel.is/c++draft/basic.start.static#2.sentence-2, and
http://eel.is/c++draft/dcl.init#general-6.2 and the new test case
actually should be accepted. However, it's also worth noting that other
compilers behave the way this patch makes Clang behave:
https://godbolt.org/z/T7noqhdPr
See post-commit discussion on https://reviews.llvm.org/D120305.
This change breaks the clang-ppc64le-rhel buildbot, though
there is suspicion that it's an issue with the bot. The change
also had a larger than expected impact on compile-time and
code-size.
This reverts commit 3c4ed02698
and some followup changes.
Default the option introduced in D113372 to ON to match all(?) major Linux
distros. This matches GCC and improves consistency with Android and linux-musl
which always default to PIE.
Note: CLANG_DEFAULT_PIE_ON_LINUX will be removed in the future.
Reviewed By: thesamesam
Differential Revision: https://reviews.llvm.org/D120305
Otherwise callers of these functions have to check both the return value
for and the contents of the returned llvm::Optional.
Fixes#53742
Differential Revision: https://reviews.llvm.org/D119525
Adds a new option InsertBraces to insert the optional braces after
if, else, for, while, and do in C++.
Differential Revision: https://reviews.llvm.org/D120217
This adds support for http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2764.pdf,
which was adopted at the Feb 2022 WG14 meeting. That paper adds
[[noreturn]] and [[_Noreturn]] to the list of supported attributes in
C2x. These attributes have the same semantics as the [[noreturn]]
attribute in C++.
The [[_Noreturn]] attribute was added as a deprecated feature so that
translation units which include <stdnoreturn.h> do not get an error on
use of [[noreturn]] because the macro expands to _Noreturn. Users can
use -Wno-deprecated-attributes to silence the diagnostic.
Use of <stdnotreturn.h> or the noreturn macro were both deprecated.
Users can define the _CLANG_DISABLE_CRT_DEPRECATION_WARNINGS macro to
suppress the deprecation diagnostics coming from the header file.
When forming the function type from a declarator, we look for an
overloadable attribute before issuing a diagnostic in C about a
function signature containing only .... When the attribute is present,
we allow such a declaration for compatibility with the overloading
rules in C++. However, we were not looking for the attribute in all of
the places it is legal to write it on a declarator and so we only
accepted the signature in some forms and incorrectly rejected the
signature in others.
We now check for the attribute preceding the declarator instead of only
being applied to the declarator directly.
The introduction and some examples are on this page:
https://devblogs.microsoft.com/cppblog/announcing-jmc-stepping-in-visual-studio/
The `/JMC` flag enables these instrumentations:
- Insert at the beginning of every function immediately after the prologue with
a call to `void __fastcall __CheckForDebuggerJustMyCode(unsigned char *JMC_flag)`.
The argument for `__CheckForDebuggerJustMyCode` is the address of a boolean
global variable (the global variable is initialized to 1) with the name
convention `__<hash>_<filename>`. All such global variables are placed in
the `.msvcjmc` section.
- The `<hash>` part of `__<hash>_<filename>` has a one-to-one mapping
with a directory path. MSVC uses some unknown hashing function. Here I
used DJB.
- Add a dummy/empty COMDAT function `__JustMyCode_Default`.
- Add `/alternatename:__CheckForDebuggerJustMyCode=__JustMyCode_Default` link
option via ".drectve" section. This is to prevent failure in
case `__CheckForDebuggerJustMyCode` is not provided during linking.
Implementation:
All the instrumentations are implemented in an IR codegen pass. The pass is placed immediately before CodeGenPrepare pass. This is to not interfere with mid-end optimizations and make the instrumentation target-independent (I'm still working on an ELF port in a separate patch).
Reviewed By: hans
Differential Revision: https://reviews.llvm.org/D118428
These changes make the Clang parser recognize expression parameter pack
expansion and initializer lists in attribute arguments. Because
expression parameter pack expansion requires additional handling while
creating and instantiating templates, the support for them must be
explicitly supported through the AcceptsExprPack flag.
Handling expression pack expansions may require a delay to when the
arguments of an attribute are correctly populated. To this end,
attributes that are set to accept these - through setting the
AcceptsExprPack flag - will automatically have an additional variadic
expression argument member named DelayedArgs. This member is not
exposed the same way other arguments are but is set through the new
CreateWithDelayedArgs creator function generated for applicable
attributes.
To illustrate how to implement support for expression pack expansion
support, clang::annotate is made to support pack expansions. This is
done by making handleAnnotationAttr delay setting the actual attribute
arguments until after template instantiation if it was unable to
populate the arguments due to dependencies in the parsed expressions.
Implement P2128R6 in C++23 mode.
Unlike GCC's implementation, this doesn't try to recover when a user
meant to use a comma expression.
Because the syntax changes meaning in C++23, the patch is *NOT*
implemented as an extension. Instead, declaring an array with not
exactly 1 parameter is an error in older languages modes. There is an
off-by-default extension warning in C++23 mode.
Unlike the standard, we supports default arguments;
Ie, we assume, based on conversations in WG21, that the proposed
resolution to CWG2507 will be accepted.
We allow arrays OpenMP sections and C++23 multidimensional array to
coexist:
[a , b] multi dimensional array
[a : b] open mp section
[a, b: c] // error
The rest of the patch is relatively straight forward: we take care to
support an arbitrary number of arguments everywhere.
This patch adds more documentation for the OpenMP offloading driver.
This includes a new file that describes the overall pipeline becuase
that was not previously explained in full elsewhere.
Reviewed By: ABataev
Differential Revision: https://reviews.llvm.org/D118815
This updates all the non-runtime project release notes to use the
version number from CMake instead of the hard-coded version numbers
in conf.py.
It also hides warnings about pre-releases when the git suffix
is dropped from the LLVM version in CMake.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D112181
This patch introduces a linker wrapper tool that allows us to preprocess
files before they are sent to the linker. This adds a dummy action and
job to the driver stage that builds the linker command as usual and then
replaces the command line with the wrapper tool.
Depends on D116543
Reviewed By: JonChesterfield
Differential Revision: https://reviews.llvm.org/D116544
to give users a final warning that they need to migrate away. They could still
use -flegacy-pass-manager for Clang 14.0.0, but the functionality may not work
for 15.0.0.
-fexperimental-new-pass-manager is a no-op for default builds, so not urgent to
be removed for 14.0.0.
clang/test/Frontend/optimization-remark-with-hotness.c is removed because its
new PM replacement optimization-remark-with-hotness-new-pm.c exists.
Reviewed By: aeubanks, nikic
Differential Revision: https://reviews.llvm.org/D118313
Part of the _BitInt feature in C2x
(http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2763.pdf) is a new
macro in limits.h named BITINT_MAXWIDTH that can be used to determine
the maximum width of a bit-precise integer type. This macro must expand
to a value that is at least as large as ULLONG_WIDTH.
This adds an implementation-defined macro named __BITINT_MAXWIDTH__ to
specify that value, which is used by limits.h for the standard macro.
This also limits the maximum bit width to 128 bits because backends do
not currently support all mathematical operations (such as division) on
wider types yet. This maximum is expected to be increased in the future.
This matches GCC: https://godbolt.org/z/sM5q95PGY
I realize this is an API break for clang+clang - so I'm totally open to
discussing how we should deal with that. If Apple wants to keep the
Clang layout indefinitely, if we want to put a flag on this so non-Apple
folks can opt out of this fix/new behavior.
Differential Revision: https://reviews.llvm.org/D117616
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
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
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.
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
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.
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
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
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
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
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
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
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.
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
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
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.
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.
Responding to a Discord call to help {D113977} and heavily inspired by the unlanded {D34225} add some support to help coroutinues from not being formatted from
```for co_await(auto elt : seq)```
to
```
for
co_await(auto elt : seq)
```
Because of the dominance of clang-format in the C++ community, I don't think we should make it the blocker that prevents users from embracing the newer parts of the standard because we butcher the layout of some of the new constucts.
Reviewed By: HazardyKnusperkeks, Quuxplusone, ChuanqiXu
Differential Revision: https://reviews.llvm.org/D114859
https://bugs.llvm.org/show_bug.cgi?id=52517
clang-format is butchering modules, this could easily become a barrier to entry for modules given clang-formats wide spread use.
Prevent the following from adding spaces around the `:` (cf was considering the ':' as an InheritanceColon)
Reviewed By: HazardyKnusperkeks, owenpan, ChuanqiXu
Differential Revision: https://reviews.llvm.org/D114151
From GCC's manpage:
-fplugin-arg-name-key=value
Define an argument called key with a value of value for the
plugin called name.
Since we don't have a key-value pair similar to gcc's plugin_argument
struct, simply accept key=value here anyway and pass it along as-is to
plugins.
This translates to the already existing '-plugin-arg-pluginname arg'
that clang cc1 accepts.
There is an ambiguity here because in clang, both the plugin name
as well as the option name can contain dashes, so when e.g. passing
-fplugin-arg-foo-bar-foo
it is not clear whether the plugin is foo-bar and the option is foo,
or the plugin is foo and the option is bar-foo. GCC solves this by
interpreting all dashes as part of the option name. So dashes can't be
part of the plugin name in this case.
Differential Revision: https://reviews.llvm.org/D113250
Operations are emulated by software emulation and “float” instructions.
This patch is allowing the support of _Float16 type without the use of
-max512fp16 flag. The final goal being, perform _Float16 emulation for
all arithmetic expressions.
The coding style of some projects requires to have more control on space
before opening parentheses.
The goal is to add the support of clang-format to more projects.
For example adding a space only for function definitions or
declarations.
This revision adds SpaceBeforeParensOptions to configure each option
independently from one another.
Differentiel Revision: https://reviews.llvm.org/D110833
This provides better support for `LambdaCapture`s by making them first-
class and allowing them to be bindable. In addition, this implements several
`LambdaCapture`-related matchers. This does not update how lambdas are
traversed. As a result, something like trying to match `lambdaCapture()` by
itself will not work - it must be used as an inner matcher.
Reviewed By: aaron.ballman, sammccall
Differential Revision: https://reviews.llvm.org/D112491
This patch ensures that we always tune for a given CPU on AArch64
targets when the user specifies the "-mtune=xyz" flag. In the
AArch64Subtarget if the tune flag is unset we use the CPU value
instead.
I've updated the release notes here:
llvm/docs/ReleaseNotes.rst
and added tests here:
clang/test/Driver/aarch64-mtune.c
Differential Revision: https://reviews.llvm.org/D110258
Previously, we reported the same value as for C17, now we report 202000L, which
is the same value currently used by GCC.
Once C23 ships, this value will be bumped to the correct date.
The C and C++ standards require the argument to __has_cpp_attribute and
__has_c_attribute to be expanded ([cpp.cond]p5). It would make little sense
to expand the argument to those operators but not expand the argument to
__has_attribute and __has_declspec, so those were both also changed in this
patch.
Note that it might make sense for the other builtins to also expand their
argument, but it wasn't as clear to me whether the behavior would be correct
there, and so they were left for a future revision.
Developers these days seem to argue over east vs west const like they used to argue over tabs vs whitespace or the various bracing style. These previous arguments were mainly eliminated with tools like `clang-format` that allowed those rules to become part of your style guide. Anyone who has been using clang-format in a large team over the last couple of years knows that we don't have those religious arguments any more, and code reviews are more productive.
https://www.youtube.com/watch?v=fv--IKZFVO8https://mariusbancila.ro/blog/2018/11/23/join-the-east-const-revolution/https://www.youtube.com/watch?v=z6s6bacI424
The purpose of this revision is to try to do the same for the East/West const discussion. Move the debate into the style guide and leave it there!
In addition to the new `ConstStyle: Right` or `ConstStyle: Left` there is an additional command-line argument `--const-style=left/right` which would allow an individual developer to switch the source back and forth to their own style for editing, and back to the committed style before commit. (you could imagine an IDE might offer such a switch)
The revision works by implementing a separate pass of the Annotated lines much like the SortIncludes and then create replacements for constant type declarations.
Differential Revision: https://reviews.llvm.org/D69764
SelectionDAG will promote illegal types up to a power of 2 before
splitting down to a legal type. This will create an IntegerType
with a bit width that must be <= MAX_INT_BITS. This places an
effective upper limit on any type of 2^23 so that we don't try
create a 2^24 type.
I considered putting a fatal error somewhere in the path from
TargetLowering::getTypeConversion down to IntegerType::get, but
limiting the type in IR seemed better.
This breaks backwards compatibility with IR that is using a really
large type. I suspect such IR is going to be very rare due to the
the compile time costs such a type likely incurs.
Prevents the ICE in PR51829.
Reviewed By: efriedma, aaron.ballman
Differential Revision: https://reviews.llvm.org/D109721
Add documentation of clang-nvlink-wrapper tool in clang.
Add it to the release notes of clang. Fix a small MSVC
warning.
Differential Revision: https://reviews.llvm.org/D109225
This change would treat the token `or` in system headers as an
identifier, and elsewhere as an operator. As reported in
llvm.org/pr42427, many users classify their third party library headers
as "system" headers to suppress warnings. There's no clean way to
separate Windows SDK headers from user headers.
Clang is still able to parse old Windows SDK headers if C++ operator
names are disabled. Traditionally this was controlled by
`-fno-operator-names`, but is now also enabled with `/permissive` since
D103773. This change will prevent `clang-cl` from parsing <query.h> from
the Windows SDK out of the box, but there are multiple ways to work
around that:
- Pass `/clang:-fno-operator-names`
- Pass `/permissive`
- Pass `-DQUERY_H_RESTRICTION_PERMISSIVE`
In all of these modes, the operator names will consistently be available
or not available, instead of depending on whether the code is in a
system header.
I added a release note for this, since it may break straightforward
users of the Windows SDK.
Fixes PR42427
Differential Revision: https://reviews.llvm.org/D108720
Add support for the GNU C style __attribute__((error(""))) and
__attribute__((warning(""))). These attributes are meant to be put on
declarations of functions whom should not be called.
They are frequently used to provide compile time diagnostics similar to
_Static_assert, but which may rely on non-ICE conditions (ie. relying on
compiler optimizations). This is also similar to diagnose_if function
attribute, but can diagnose after optimizations have been run.
While users may instead simply call undefined functions in such cases to
get a linkage failure from the linker, these provide a much more
ergonomic and actionable diagnostic to users and do so at compile time
rather than at link time. Users instead may be able use inline asm .err
directives.
These are used throughout the Linux kernel in its implementation of
BUILD_BUG and BUILD_BUG_ON macros. These macros generally cannot be
converted to use _Static_assert because many of the parameters are not
ICEs. The Linux kernel still needs to be modified to make use of these
when building with Clang; I have a patch that does so I will send once
this feature is landed.
To do so, we create a new IR level Function attribute, "dontcall" (both
error and warning boil down to one IR Fn Attr). Then, similar to calls
to inline asm, we attach a !srcloc Metadata node to call sites of such
attributed callees.
The backend diagnoses these during instruction selection, while we still
know that a call is a call (vs say a JMP that's a tail call) in an arch
agnostic manner.
The frontend then reconstructs the SourceLocation from that Metadata,
and determines whether to emit an error or warning based on the callee's
attribute.
Link: https://bugs.llvm.org/show_bug.cgi?id=16428
Link: https://github.com/ClangBuiltLinux/linux/issues/1173
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D106030
This should reduce the amount of noise issued by clang for the recent-ish CUDA
versions.
Clang still does not support all the features offered by NVCC, but is expected
to handle CUDA headers and produce binaries for all GPUs supported by NVCC.
Differential Revision: https://reviews.llvm.org/D108248
This implements P2362, which has not yet been approved by the
C++ committee, but because wide-multi character literals are
implementation defined, clang might not have to wait for WG21.
This change is also being applied in C mode as the behavior is
implementation-defined in C as well and there's no benefit to
having different rules between the languages.
The other part of P2362, making non-representable character
literals ill-formed, is already implemented by clang
Previously, with AllowShortEnumsOnASingleLine disabled, enums that would have otherwise fit on a single line would always put the opening brace on its own line.
This patch ensures that these enums will only put the brace on its own line if the existing attachment rules indicate that it should.
Reviewed By: HazardyKnusperkeks, curdeius
Differential Revision: https://reviews.llvm.org/D99840
Summary:
Test and produce warning for subtracting a pointer from null or subtracting
null from a pointer.
This reland adds the functionality that the warning is no longer reusing an
existing warning, it has different wording for C vs C++ to refect the fact
that nullptr-nullptr has defined behaviour in C++, it is suppressed
when the warning is triggered by a system header and adds
-Wnull-pointer-subtraction to allow the warning to be controlled. -Wextra
implies -Wnull-pointer-subtraction.
Author: Jamie Schmeiser <schmeise@ca.ibm.com>
Reviewed By: efriedma (Eli Friedman), nickdesaulniers (Nick Desaulniers)
Differential Revision: https://reviews.llvm.org/D98798
I find as I develop I'm moving between many different languages C++,C#,JavaScript all the time. As I move between the file types I like to keep `clang-format` as my formatting tool of choice. (hence why I initially added C# support in {D58404}) I know those other languages have their own tools but I have to learn them all, and I have to work out how to configure them, and they may or may not have integration into my IDE or my source code integration.
I am increasingly finding that I'm editing additional JSON files as part of my daily work and my editor and git commit hooks are just not setup to go and run [[ https://stedolan.github.io/jq/ | jq ]], So I tend to go to [[ https://jsonformatter.curiousconcept.com/ | JSON Formatter ]] and copy and paste back and forth. To get nicely formatted JSON. This is a painful process and I'd like a new one that causes me much less friction.
This has come up from time to time:
{D10543}
https://stackoverflow.com/questions/35856565/clang-format-a-json-filehttps://bugs.llvm.org/show_bug.cgi?id=18699
I would like to stop having to do that and have formatting JSON as a first class clang-format support `Language` (even if it has minimal style settings at present).
This revision adds support for formatting JSON using the inbuilt JSON serialization library of LLVM, With limited control at present only over the indentation level
This adds an additional Language into the .clang-format file to separate the settings from your other supported languages.
Reviewed By: HazardyKnusperkeks
Differential Revision: https://reviews.llvm.org/D93528
Currently the lambda body indents relative to where the lambda signature is located. This instead lets the user
choose to align the lambda body relative to the parent scope that contains the lambda declaration. Thus:
someFunction([] {
lambdaBody();
});
will always have the same indentation of the body even when the lambda signature goes on a new line:
someFunction(
[] {
lambdaBody();
});
whereas before lambdaBody would be indented 6 spaces.
Differential Revision: https://reviews.llvm.org/D102706
This allows to set a different indent width for preprocessor statements.
Example:
#ifdef __linux_
# define FOO
#endif
int main(void)
{
return 0;
}
Differential Revision: https://reviews.llvm.org/D103286
This re-applies the old patch D27651, which was never landed, into the
latest "main" branch, without understanding the code. I just applied
the changes "mechanically" and made it compiling again.
This makes the right pointer alignment working as expected.
Fixes https://llvm.org/PR27353
For instance
const char* const* v1;
float const* v2;
SomeVeryLongType const& v3;
was formatted as
const char *const * v1;
float const * v2;
SomeVeryLongType const &v3;
This patch keep the *s or &s aligned to the right, next to their variable.
The above example is now formatted as
const char *const *v1;
float const *v2;
SomeVeryLongType const &v3;
It is a pity that this still does not work with clang-format in 2021,
even though there was a fix available in 2016. IMHO right pointer alignment
is the default case in C, because syntactically the pointer belongs to the
variable.
See
int* a, b, c; // wrong, just the 1st variable is a pointer
vs.
int *a, *b, *c; // right
Prominent example is the Linux kernel coding style.
Some styles argue the left pointer alignment is better and declaration
lists as shown above should be avoided. That's ok, as different projects
can use different styles, but this important style should work too.
I hope that somebody that has a better understanding about the code,
can take over this patch and land it into main.
For now I must maintain this fork to make it working for our projects.
Cheers,
Gerhard.
Differential Revision: https://reviews.llvm.org/D103245
This is a re-application of dc67299 which was reverted in f63adf5b because
it broke the build. The issue should now be fixed.
Attribution note: The original author of this patch is Erik Pilkington.
I'm only trying to land it after rebasing.
Differential Revision: https://reviews.llvm.org/D91630
This inheritance list style has been widely adopted by Symantec,
a division of Broadcom Inc. It breaks after the commas that
separate the base-specifiers:
class Derived : public Base1,
private Base2
{
};
Differential Revision: https://reviews.llvm.org/D103204
This patch adds support for GCC's -fstack-usage flag. With this flag, a stack
usage file (i.e., .su file) is generated for each input source file. The format
of the stack usage file is also similar to what is used by GCC. For each
function defined in the source file, a line with the following information is
produced in the .su file.
<source_file>:<line_number>:<function_name> <size_in_byte> <static/dynamic>
"Static" means that the function's frame size is static and the size info is an
accurate reflection of the frame size. While "dynamic" means the function's
frame size can only be determined at run-time because the function manipulates
the stack dynamically (e.g., due to variable size objects). The size info only
reflects the size of the fixed size frame objects in this case and therefore is
not a reliable measure of the total frame size.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D100509
This fixes PR46992.
Git stores symlinks as text files and we should not format them even if
they have one of the requested extensions.
(Move the call to `cd_to_toplevel()` up a few lines so we can also print
the skipped symlinks during verbose output.)
Differential Revision: https://reviews.llvm.org/D101878
Warn when a declaration uses an identifier that doesn't obey the reserved
identifier rule from C and/or C++.
Differential Revision: https://reviews.llvm.org/D93095
Nick Kreeger