The (function) type of the lambda function is null while parsing
trailing return type. The type is filled-in when the lambda body is
entered. So, resolving `__PRETTY_FUNCTION__` before the lambda body is
entered causes the crash.
Fixes#121274.
This reverts commit 81fc3add1e627c23b7270fe2739cdacc09063e54.
This breaks some LLDB tests, e.g.
SymbolFile/DWARF/x86/no_unique_address-with-bitfields.cpp:
lldb: ../llvm-project/clang/lib/AST/Decl.cpp:4604: unsigned int clang::FieldDecl::getBitWidthValue() const: Assertion `isa<ConstantExpr>(getBitWidth())' failed.
Save the bitwidth value as a `ConstantExpr` with the value set. Remove
the `ASTContext` parameter from `getBitWidthValue()`, so the latter
simply returns the value from the `ConstantExpr` instead of
constant-evaluating the bitwidth expression every time it is called.
Re-write the sema and codegen for the atomic_test_and_set and
atomic_clear builtin functions to go via AtomicExpr, like the other
atomic builtins do. This simplifies the code, because AtomicExpr already
handles things like generating code for to dynamically select the memory
ordering, which was duplicated for these builtins. This also fixes a few
crash bugs, one when passing an integer to the pointer argument, and one
when using an array.
This also adds diagnostics for the memory orderings which are not valid
for atomic_clear according to
https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html, which
were missing before.
Fixes#111293.
This is a rebase of #95112 with my own feedback apply as @MitalAshok has
been inactive for a while.
It's fairly important this makes clang 20 as it is a blocker for #107451
---
[CWG2813](https://cplusplus.github.io/CWG/issues/2813.html)
prvalue.member_fn(expression-list) now will not materialize a temporary
for prvalue if member_fn is an explicit object member function, and
prvalue will bind directly to the object parameter.
The E1 in E1.static_member is now a discarded-value expression, so if E1
was a call to a [[nodiscard]] function, there will now be a warning.
This also affects C++98 with [[gnu::warn_unused_result]] functions.
This should not affect C where TemporaryMaterializationConversion is a
no-op.
Closes#100314Fixes#100341
---------
Co-authored-by: Mital Ashok <mital@mitalashok.co.uk>
A follow-up to #112289.
When diagnosing an unused return value, if the diagnostic
is triggered by an attribute attached to a type, the type name
is now included in the diagnostic.
---------
Co-authored-by: Sirraide <aeternalmail@gmail.com>
The 'tile' clause shares quite a bit of the rules with 'collapse', so a
followup patch will add those tests/behaviors. This patch deals with
adding the AST node.
The 'tile' clause takes a series of integer constant expressions, or *.
The asterisk is now represented by a new OpenACCAsteriskSizeExpr node,
else this clause is very similar to others.
* Don't call raw_string_ostream::flush(), which is essentially a no-op.
* Strip unneeded calls to raw_string_ostream::str(), to avoid extra indirection.
HLSL allows implicit conversions to truncate vectors to scalar
pr-values. These conversions are scored as vector truncations and should
warn appropriately.
This change allows forming a truncation cast to a pr-value, but not an
l-value. Truncating a vector to a scalar is performed by loading the
first element of the vector and disregarding the remaining elements.
Fixes#102964
This patch is the frontend implementation of the coroutine elide
improvement project detailed in this discourse post:
https://discourse.llvm.org/t/language-extension-for-better-more-deterministic-halo-for-c-coroutines/80044
This patch proposes a C++ struct/class attribute
`[[clang::coro_await_elidable]]`. This notion of await elidable task
gives developers and library authors a certainty that coroutine heap
elision happens in a predictable way.
Originally, after we lower a coroutine to LLVM IR, CoroElide is
responsible for analysis of whether an elision can happen. Take this as
an example:
```
Task foo();
Task bar() {
co_await foo();
}
```
For CoroElide to happen, the ramp function of `foo` must be inlined into
`bar`. This inlining happens after `foo` has been split but `bar` is
usually still a presplit coroutine. If `foo` is indeed a coroutine, the
inlined `coro.id` intrinsics of `foo` is visible within `bar`. CoroElide
then runs an analysis to figure out whether the SSA value of
`coro.begin()` of `foo` gets destroyed before `bar` terminates.
`Task` types are rarely simple enough for the destroy logic of the task
to reference the SSA value from `coro.begin()` directly. Hence, the pass
is very ineffective for even the most trivial C++ Task types. Improving
CoroElide by implementing more powerful analyses is possible, however it
doesn't give us the predictability when we expect elision to happen.
The approach we want to take with this language extension generally
originates from the philosophy that library implementations of `Task`
types has the control over the structured concurrency guarantees we
demand for elision to happen. That is, the lifetime for the callee's
frame is shorter to that of the caller.
The ``[[clang::coro_await_elidable]]`` is a class attribute which can be
applied to a coroutine return type.
When a coroutine function that returns such a type calls another
coroutine function, the compiler performs heap allocation elision when
the following conditions are all met:
- callee coroutine function returns a type that is annotated with
``[[clang::coro_await_elidable]]``.
- In caller coroutine, the return value of the callee is a prvalue that
is immediately `co_await`ed.
From the C++ perspective, it makes sense because we can ensure the
lifetime of elided callee cannot exceed that of the caller if we can
guarantee that the caller coroutine is never destroyed earlier than the
callee coroutine. This is not generally true for any C++ programs.
However, the library that implements `Task` types and executors may
provide this guarantee to the compiler, providing the user with
certainty that HALO will work on their programs.
After this patch, when compiling coroutines that return a type with such
attribute, the frontend checks that the type of the operand of
`co_await` expressions (not `operator co_await`). If it's also
attributed with `[[clang::coro_await_elidable]]`, the FE emits metadata
on the call or invoke instruction as a hint for a later middle end pass
to elide the elision.
The original patch version is
https://github.com/llvm/llvm-project/pull/94693 and as suggested, the
patch is split into frontend and middle end solutions into stacked PRs.
The middle end CoroSplit patch can be found at
https://github.com/llvm/llvm-project/pull/99283
The middle end transformation that performs the elide can be found at
https://github.com/llvm/llvm-project/pull/99285
Parsing lambdas require pushing a declaration context for the lambda, so
that parameters can be attached to it, before its trailing type is
parsed. DAt that point, partially-parsed lambda don't have a name that
can be computed for then.
This would cause source_location::current() to crash when use in the
decltype of a lambda().
We work around this by producing a source_location for an enclosing
scope in that scenario.
Fixes#67134
HLSL output parameters are denoted with the `inout` and `out` keywords
in the function declaration. When an argument to an output parameter is
constructed a temporary value is constructed for the argument.
For `inout` pamameters the argument is initialized via copy-initialization
from the argument lvalue expression to the parameter type. For `out`
parameters the argument is not initialized before the call.
In both cases on return of the function the temporary value is written
back to the argument lvalue expression through an implicit assignment
binary operator with casting as required.
This change introduces a new HLSLOutArgExpr ast node which represents
the output argument behavior. The OutArgExpr has three defined children:
- An OpaqueValueExpr of the argument lvalue expression.
- An OpaqueValueExpr of the copy-initialized parameter.
- A BinaryOpExpr assigning the first with the value of the second.
Fixes#87526
---------
Co-authored-by: Damyan Pepper <damyanp@microsoft.com>
Co-authored-by: John McCall <rjmccall@gmail.com>
From @vitalybuka's review on
https://github.com/llvm/llvm-project/pull/104889:
- [x] remove unused variable in tests
- [x] rename `post-decr-while` --> `unsigned-post-decr-while`
- [x] split `add-overflow-test` into `add-unsigned-overflow-test` and
`add-signed-overflow-test`
- [x] be more clear about defaults within docs
- [x] add table to docs
Here's a screenshot of the rendered table so you don't have to build the
html docs yourself to inspect the layout:
CCs: @vitalybuka
---------
Signed-off-by: Justin Stitt <justinstitt@google.com>
Co-authored-by: Vitaly Buka <vitalybuka@google.com>
Introduce "-fsanitize-undefined-ignore-overflow-pattern=" which can
be used to disable sanitizer instrumentation for common overflow-dependent
code patterns.
For a wide selection of projects, proper overflow sanitization could
help catch bugs and solve security vulnerabilities. Unfortunately, in
some cases the integer overflow sanitizers are too noisy for their users
and are often left disabled. Providing users with a method to disable
sanitizer instrumentation of common patterns could mean more projects
actually utilize the sanitizers in the first place.
One such project that has opted to not use integer overflow (or
truncation) sanitizers is the Linux Kernel. There has been some
discussion[1] recently concerning mitigation strategies for unexpected
arithmetic overflow. This discussion is still ongoing and a succinct
article[2] accurately sums up the discussion. In summary, many Kernel
developers do not want to introduce more arithmetic wrappers when
most developers understand the code patterns as they are.
Patterns like:
if (base + offset < base) { ... }
or
while (i--) { ... }
or
#define SOME -1UL
are extremely common in a code base like the Linux Kernel. It is
perhaps too much to ask of kernel developers to use arithmetic wrappers
in these cases. For example:
while (wrapping_post_dec(i)) { ... }
which wraps some builtin would not fly. This would incur too many
changes to existing code; the code churn would be too much, at least too
much to justify turning on overflow sanitizers.
Currently, this commit tackles three pervasive idioms:
1. "if (a + b < a)" or some logically-equivalent re-ordering like "if (a > b + a)"
2. "while (i--)" (for unsigned) a post-decrement always overflows here
3. "-1UL, -2UL, etc" negation of unsigned constants will always overflow
The patterns that are excluded can be chosen from the following list:
- add-overflow-test
- post-decr-while
- negated-unsigned-const
These can be enabled with a comma-separated list:
-fsanitize-undefined-ignore-overflow-pattern=add-overflow-test,negated-unsigned-const
"all" or "none" may also be used to specify that all patterns should be
excluded or that none should be.
[1] https://lore.kernel.org/all/202404291502.612E0A10@keescook/
[2] https://lwn.net/Articles/979747/
CCs: @efriedma-quic @kees @jyknight @fmayer @vitalybuka
Signed-off-by: Justin Stitt <justinstitt@google.com>
Co-authored-by: Bill Wendling <morbo@google.com>
Introduce "-fsanitize-overflow-pattern-exclusion=" which can be used to
disable sanitizer instrumentation for common overflow-dependent code
patterns.
For a wide selection of projects, proper overflow sanitization could
help catch bugs and solve security vulnerabilities. Unfortunately, in
some cases the integer overflow sanitizers are too noisy for their users
and are often left disabled. Providing users with a method to disable
sanitizer instrumentation of common patterns could mean more projects
actually utilize the sanitizers in the first place.
One such project that has opted to not use integer overflow (or
truncation) sanitizers is the Linux Kernel. There has been some
discussion[1] recently concerning mitigation strategies for unexpected
arithmetic overflow. This discussion is still ongoing and a succinct
article[2] accurately sums up the discussion. In summary, many Kernel
developers do not want to introduce more arithmetic wrappers when
most developers understand the code patterns as they are.
Patterns like:
if (base + offset < base) { ... }
or
while (i--) { ... }
or
#define SOME -1UL
are extremely common in a code base like the Linux Kernel. It is
perhaps too much to ask of kernel developers to use arithmetic wrappers
in these cases. For example:
while (wrapping_post_dec(i)) { ... }
which wraps some builtin would not fly. This would incur too many
changes to existing code; the code churn would be too much, at least too
much to justify turning on overflow sanitizers.
Currently, this commit tackles three pervasive idioms:
1. "if (a + b < a)" or some logically-equivalent re-ordering like "if (a > b + a)"
2. "while (i--)" (for unsigned) a post-decrement always overflows here
3. "-1UL, -2UL, etc" negation of unsigned constants will always overflow
The patterns that are excluded can be chosen from the following list:
- add-overflow-test
- post-decr-while
- negated-unsigned-const
These can be enabled with a comma-separated list:
-fsanitize-overflow-pattern-exclusion=add-overflow-test,negated-unsigned-const
"all" or "none" may also be used to specify that all patterns should be
excluded or that none should be.
[1] https://lore.kernel.org/all/202404291502.612E0A10@keescook/
[2] https://lwn.net/Articles/979747/
CCs: @efriedma-quic @kees @jyknight @fmayer @vitalybuka
Signed-off-by: Justin Stitt <justinstitt@google.com>
Co-authored-by: Bill Wendling <morbo@google.com>
This patch makes remaining cases of #embed to emit int type since there
is an agreement to do that for C. C++ is being discussed, but in general
we don't want to produce different types for C and C++.
This commit implements the entirety of the now-accepted [N3017
-Preprocessor
Embed](https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3017.htm) and
its sister C++ paper [p1967](https://wg21.link/p1967). It implements
everything in the specification, and includes an implementation that
drastically improves the time it takes to embed data in specific
scenarios (the initialization of character type arrays). The mechanisms
used to do this are used under the "as-if" rule, and in general when the
system cannot detect it is initializing an array object in a variable
declaration, will generate EmbedExpr AST node which will be expanded by
AST consumers (CodeGen or constant expression evaluators) or expand
embed directive as a comma expression.
This reverts commit
682d461d5a.
---------
Co-authored-by: The Phantom Derpstorm <phdofthehouse@gmail.com>
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
Co-authored-by: cor3ntin <corentinjabot@gmail.com>
Co-authored-by: H. Vetinari <h.vetinari@gmx.com>
Used to implement CWG2191 where `typeid` for a polymorphic glvalue only
becomes potentially-throwing if the `typeid` operand was already
potentially throwing or a `nullptr` check was inserted:
https://cplusplus.github.io/CWG/issues/2191.html
Also change `Expr::hasSideEffects` for `CXXTypeidExpr` to check the
operand for side-effects instead of always reporting that there are
side-effects
Remove `IsDeref` parameter of `CGCXXABI::shouldTypeidBeNullChecked`
because it should never return `true` if `!IsDeref` (we shouldn't add a
null check that wasn't there in the first place)
This commit implements the entirety of the now-accepted [N3017 -
Preprocessor
Embed](https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3017.htm) and
its sister C++ paper [p1967](https://wg21.link/p1967). It implements
everything in the specification, and includes an implementation that
drastically improves the time it takes to embed data in specific
scenarios (the initialization of character type arrays). The mechanisms
used to do this are used under the "as-if" rule, and in general when the
system cannot detect it is initializing an array object in a variable
declaration, will generate EmbedExpr AST node which will be expanded
by AST consumers (CodeGen or constant expression evaluators) or
expand embed directive as a comma expression.
---------
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
Co-authored-by: cor3ntin <corentinjabot@gmail.com>
Co-authored-by: H. Vetinari <h.vetinari@gmx.com>
Co-authored-by: Podchishchaeva, Mariya <mariya.podchishchaeva@intel.com>
Reapplies #84050, addressing a bug which cases a crash when an
expression with the type of the current instantiation is used as the
_postfix-expression_ in a class member access expression (arrow form).
Consider the following:
```cpp
template<typename T>
struct A
{
auto f()
{
return this->x;
}
};
```
Although `A` has no dependent base classes and the lookup context for
`x` is the current instantiation, we currently do not diagnose the
absence of a member `x` until `A<T>::f` is instantiated. This patch
moves the point of diagnosis for such expressions to occur at the point
of definition (i.e. prior to instantiation).
OpenACC is going to need an array sections implementation that is a
simpler version/more restrictive version of the OpenMP version.
This patch moves `OMPArraySectionExpr` to `Expr.h` and renames it `ArraySectionExpr`,
then adds an enum to choose between the two.
This also fixes a couple of 'drive-by' issues that I discovered on the way,
but leaves the OpenACC Sema parts reasonably unimplemented (no semantic
analysis implementation), as that will be a followup patch.
(This patch depends on #86678)
Pretty straightforward change, addresses the FIXME's in
`computeDependence(MemberExpr*)` and `MemberExpr::Create` by moving the
template argument dependence computations to `computeDependence`.
Currently, `MemberExpr` allocates a trailing `MemberExprNameQualifier`
object if it either has a `NestedNameSpecifierLoc`, or if it names a
member found via using declaration. Since the presence of a
_nested-name-specifier_ does not necessarily imply the named member was
found via using declaration, this patch removes
`MemberExprNameQualifier` and allocates the members separately.
HLSL constant sized array function parameters do not decay to pointers.
Instead constant sized array types are preserved as unique types for
overload resolution, template instantiation and name mangling.
This implements the change by adding a new `ArrayParameterType` which
represents a non-decaying `ConstantArrayType`. The new type behaves the
same as `ConstantArrayType` except that it does not decay to a pointer.
Values of `ConstantArrayType` in HLSL decay during overload resolution
via a new `HLSLArrayRValue` cast to `ArrayParameterType`.
`ArrayParamterType` values are passed indirectly by-value to functions
in IR generation resulting in callee generated memcpy instructions.
The behavior of HLSL function calls is documented in the [draft language
specification](https://microsoft.github.io/hlsl-specs/specs/hlsl.pdf)
under the Expr.Post.Call heading.
Additionally the design of this implementation approach is documented in
[Clang's
documentation](https://clang.llvm.org/docs/HLSL/FunctionCalls.html)
Resolves#70123
Predefined macro FUNCTION in clang is not returning the same string than
MS for templated functions.
See https://godbolt.org/z/q3EKn5zq4
For the same test case MSVC is returning:
function: TestClass::TestClass
function: TestStruct::TestStruct
function: TestEnum::TestEnum
The initial work for this was in the reverted patch
(https://github.com/llvm/llvm-project/pull/66120). This patch solves the
issues raised in the reverted patch.
Enumerators dont have the type of their enumeration before the closing
brace. In these cases Expr::getEnumCoercedType() incorrectly returned
the enumeration type.
Introduced in PR #81418Fixes#84712
…C mode
Factored logic from `CheckImplicitConversion` into new methods
`Expr::getEnumConstantDecl` and `Expr::getEnumCoercedType` for use in
`checkEnumArithmeticConversions`.
Fix#29217
HLSL supports vector truncation and element conversions as part of
standard conversion sequences. The vector truncation conversion is a C++
second conversion in the conversion sequence. If a vector truncation is
in a conversion sequence an element conversion may occur after it before
the standard C++ third conversion.
Vector element conversions can be boolean conversions, floating point or
integral conversions or promotions.
[HLSL Draft
Specification](https://microsoft.github.io/hlsl-specs/specs/hlsl.pdf)
---------
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
This code was correct as written prior to C++17, which allowed bases to
appear in the initializer list.
This was observable by creating non-constant aggregate initialization at
file scope in a compound literal, but since that behavior will change
soon if we implement support for dynamic initialization, I also added a
unit test for `isConstantInitializer`.
This fixes at least one part of issue #80510 .
---------
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
Implements https://isocpp.org/files/papers/P2662R3.pdf
The feature is exposed as an extension in older language modes.
Mangling is not yet supported and that is something we will have to do before release.
SourceLocExpr that may produce a function name are marked dependent so that the non-instantiated
name of a function does not get evaluated.
In GH78128, the name('s size) is used as
template argument to a `DeclRef` that is not otherwise dependent, and therefore cached and not transformed when the function is
instantiated, leading to 2 different values existing at the same time for the same function.
Fixes#78128
The 'counted_by' attribute is used on flexible array members. The
argument for the attribute is the name of the field member holding the
count of elements in the flexible array. This information is used to
improve the results of the array bound sanitizer and the
'__builtin_dynamic_object_size' builtin. The 'count' field member must
be within the same non-anonymous, enclosing struct as the flexible array
member. For example:
```
struct bar;
struct foo {
int count;
struct inner {
struct {
int count; /* The 'count' referenced by 'counted_by' */
};
struct {
/* ... */
struct bar *array[] __attribute__((counted_by(count)));
};
} baz;
};
```
This example specifies that the flexible array member 'array' has the
number of elements allocated for it in 'count':
```
struct bar;
struct foo {
size_t count;
/* ... */
struct bar *array[] __attribute__((counted_by(count)));
};
```
This establishes a relationship between 'array' and 'count';
specifically that 'p->array' must have *at least* 'p->count' number of
elements available. It's the user's responsibility to ensure that this
relationship is maintained throughout changes to the structure.
In the following, the allocated array erroneously has fewer elements
than what's specified by 'p->count'. This would result in an
out-of-bounds access not not being detected:
```
struct foo *p;
void foo_alloc(size_t count) {
p = malloc(MAX(sizeof(struct foo),
offsetof(struct foo, array[0]) + count *
sizeof(struct bar *)));
p->count = count + 42;
}
```
The next example updates 'p->count', breaking the relationship
requirement that 'p->array' must have at least 'p->count' number of
elements available:
```
void use_foo(int index, int val) {
p->count += 42;
p->array[index] = val; /* The sanitizer can't properly check this access */
}
```
In this example, an update to 'p->count' maintains the relationship
requirement:
```
void use_foo(int index, int val) {
if (p->count == 0)
return;
--p->count;
p->array[index] = val;
}
```
