A FieldDecl that's an empty struct may not show up in CGRecordLayout. Go
ahead and ignore such a field as it shouldn't make a difference to these
calculations.
Fixes: 1f6f97e2b6 ("[Clang] Loop over FieldDecls instead of all Decls (#99574)")
Co-authored-by: Eli Friedman <efriedma@quicinc.com>
Only FieldDecls are important when determining GEP indices. A struct
defined within another struct has the same semantics as if it were
defined outside of the struct. So there's no need to look into
RecordDecls that aren't a field.
See commit 5bcf31ebfa ("[Clang] Loop over FieldDecls instead of all
Decls (#89453)")
Fixes 2039.
Re-signing occurs when function type discrimination is enabled and a
function pointer is converted to another function pointer type that
requires signing using a different discriminator. A function pointer is
re-signed using discriminator zero when it's converted to a pointer to a
non-function type such as `void*`.
---------
Co-authored-by: Ahmed Bougacha <ahmed@bougacha.org>
Co-authored-by: John McCall <rjmccall@apple.com>
This is a follow-up from the conversation starting at
https://github.com/llvm/llvm-project/pull/93809#issuecomment-2173729801
The root problem that motivated the change are external AST sources that
compute `ASTRecordLayout`s themselves instead of letting Clang compute
them from the AST. One such example is LLDB using DWARF to get the
definitive offsets and sizes of C++ structures. Such layouts should be
considered correct (modulo buggy DWARF), but various assertions and
lowering logic around the `CGRecordLayoutBuilder` relies on the AST
having `[[no_unique_address]]` attached to them. This is a
layout-altering attribute which is not encoded in DWARF. This causes us
LLDB to trip over the various LLVM<->Clang layout consistency checks.
There has been precedent for avoiding such layout-altering attributes
from affecting lowering with externally-provided layouts (e.g., packed
structs).
This patch proposes to replace the `isZeroSize` checks in
`CGRecordLayoutBuilder` (which roughly means "empty field with
[[no_unique_address]]") with checks for
`CodeGen::isEmptyField`/`CodeGen::isEmptyRecord`.
**Details**
The main strategy here was to change the `isZeroSize` check in
`CGRecordLowering::accumulateFields` and
`CGRecordLowering::accumulateBases` to use the `isEmptyXXX` APIs
instead, preventing empty fields from being added to the `Members` and
`Bases` structures. The rest of the changes fall out from here, to
prevent lookups into these structures (for field numbers or base
indices) from failing.
Added `isEmptyRecordForLayout` and `isEmptyFieldForLayout` (open to
better naming suggestions). The main difference to the existing
`isEmptyRecord`/`isEmptyField` APIs, is that the `isEmptyXXXForLayout`
counterparts don't have special treatment for `unnamed bitfields`/arrays
and also treat fields of empty types as if they had
`[[no_unique_address]]` (i.e., just like the `AsIfNoUniqueAddr` in
`isEmptyField` does).
There are two problems with _BitInt prior to this patch:
1. For at least some values of N, we cannot use LLVM's iN for the type
of struct elements, array elements, allocas, global variables, and so
on, because the LLVM layout for that type does not match the high-level
layout of _BitInt(N).
Example: Currently for i128:128 targets correct implementation is
possible either for __int128 or for _BitInt(129+) with lowering to iN,
but not both, since we have now correct implementation of __int128 in
place after a21abc7.
When this happens, opaque [M x i8] types used, where M =
sizeof(_BitInt(N)).
2. LLVM doesn't guarantee any particular extension behavior for integer
types that aren't a multiple of 8. For this reason, all _BitInt types
are now have in-memory representation that is a whole number of bytes.
I.e. for example _BitInt(17) now will have memory layout type i32.
This patch also introduces concept of load/store type and adds an API to
CodeGenTypes that returns the IR type that should be used for load and
store operations. This is particularly useful for the case when a
_BitInt ends up having array of bytes as memory layout type. For
_BitInt(N), let M = sizeof(_BitInt(N)), and let BITS = M * 8. Loads and
stores of iM would both (1) produce far better code from the backends
and (2) be far more optimizable by IR passes than loads and stores of [M
x i8].
Fixes https://github.com/llvm/llvm-project/issues/85139
Fixes https://github.com/llvm/llvm-project/issues/83419
---------
Co-authored-by: John McCall <rjmccall@gmail.com>
When BPF object files are linked with bpftool, every symbol must be
accompanied by BTF info. Ensure that extern functions referenced by
global variable initializers are included in BTF.
The primary motivation is "static" initialization of PROG maps:
```c
extern int elsewhere(struct xdp_md *);
struct {
__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, int);
__array(values, int (struct xdp_md *));
} prog_map SEC(".maps") = { .values = { elsewhere } };
```
BPF backend needs debug info to produce BTF. Debug info is not
normally generated for external variables and functions. Previously, it
was solved differently for variables (collecting variable declarations
in ExternalDeclarations vector) and functions (logic invoked during
codegen in CGExpr.cpp).
This patch generalises ExternalDefclarations to include both function
and variable declarations. This change ensures that function references
are not missed no matter the context. Previously external functions
referenced in constant expressions lacked debug info.
Virtual function pointer entries in v-tables are signed with address
discrimination in addition to declaration-based discrimination, where an
integer discriminator the string hash (see
`ptrauth_string_discriminator`) of the mangled name of the overridden
method. This notably provides diversity based on the full signature of
the overridden method, including the method name and parameter types.
This patch introduces ItaniumVTableContext logic to find the original
declaration of the overridden method.
On AArch64, these pointers are signed using the `IA` key (the
process-independent code key.)
V-table pointers can be signed with either no discrimination, or a
similar scheme using address and decl-based discrimination. In this
case, the integer discriminator is the string hash of the mangled
v-table identifier of the class that originally introduced the vtable
pointer.
On AArch64, these pointers are signed using the `DA` key (the
process-independent data key.)
Not using discrimination allows attackers to simply copy valid v-table
pointers from one object to another. However, using a uniform
discriminator of 0 does have positive performance and code-size
implications on AArch64, and diversity for the most important v-table
access pattern (virtual dispatch) is already better assured by the
signing schemas used on the virtual functions. It is also known that
some code in practice copies objects containing v-tables with `memcpy`,
and while this is not permitted formally, it is something that may be
invasive to eliminate.
This is controlled by:
```
-fptrauth-vtable-pointer-type-discrimination
-fptrauth-vtable-pointer-address-discrimination
```
In addition, this provides fine-grained controls in the
ptrauth_vtable_pointer attribute, which allows overriding the default
ptrauth schema for vtable pointers on a given class hierarchy, e.g.:
```
[[clang::ptrauth_vtable_pointer(no_authentication, no_address_discrimination,
no_extra_discrimination)]]
[[clang::ptrauth_vtable_pointer(default_key, default_address_discrimination,
custom_discrimination, 0xf00d)]]
```
The override is then mangled as a parametrized vendor extension:
```
"__vtptrauth" I
<key>
<addressDiscriminated>
<extraDiscriminator>
E
```
To support this attribute, this patch adds a small extension to the
attribute-emitter tablegen backend.
Note that there are known areas where signing is either missing
altogether or can be strengthened. Some will be addressed in later
changes (e.g., member function pointers, some RTTI).
`dynamic_cast` in particular is handled by emitting an artificial
v-table pointer load (in a way that always authenticates it) before the
runtime call itself, as the runtime doesn't have enough information
today to properly authenticate it. Instead, the runtime is currently
expected to strip the v-table pointer.
---------
Co-authored-by: John McCall <rjmccall@apple.com>
Co-authored-by: Ahmed Bougacha <ahmed@bougacha.org>
Without this patch compiler-rt ubsan library has a bug displaying
incorrect values for variables of the _BitInt (previously called
_ExtInt) type. This patch affects affects both: generation of metadata
inside code generator and runtime part. The runtime part provided only
for i386 and x86_64 runtimes. Other runtimes should be updated to take
full benefit of this patch.
The patch is constructed the way to be backward compatible and int and
float type runtime diagnostics should be unaffected for not yet updated
runtimes.
This patch fixes issue:
https://github.com/llvm/llvm-project/issues/64100.
Co-authored-by: Vladislav Aranov <vladislav.aranov@ericsson.com>
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
This patch simplifies instruction creation by replacing all overloads of
instruction constructors/Create methods that are identical other than
the Instruction *InsertBefore/BasicBlock *InsertAtEnd/BasicBlock::iterator
InsertBefore argument with a single version that takes an InsertPosition
argument. The InsertPosition class can be implicitly constructed from
any of the above, internally converting them to the appropriate
BasicBlock::iterator value which can then be used to insert the
instruction (or to not insert it if an invalid iterator is passed).
The upshot of this is that code will be deduplicated, and all callsites
will switch to calling the new unified version without any changes
needed to make the compiler happy. There is at least one exception to
this; the construction of InsertPosition is a user-defined conversion,
so any caller that was already relying on a different user-defined
conversion won't work. In all of LLVM and Clang this happens exactly
once: at clang/lib/CodeGen/CGExpr.cpp:123 we try to construct an alloca
with an AssertingVH<Instruction> argument, which must now be cast to an
Instruction* by using `&*`. If this is more common elsewhere, it could
be fixed by adding an appropriate constructor to InsertPosition.
llvm::hash_value is not guaranteed to be deterministic. Use the
deterministic xxh3_64bits. A strong bit mixer isn't necessary. Use a
simpler one that works well with pointers.
It does not look like particular value is inportant.
Howere, there is a comment., but the current implementation
of `create{Unlikely,Likely}BranchWeights` use the same value.
Follow up to #89464
The parameter of `getAddress()` was not being used, as I recall, and
seems to have been removed in the meantime. Merging this w/o review
since this is breaking builds.
Consider this code:
```c++
template <typename... Ts>
struct Overloaded : Ts... { using Ts::operator()...; };
template <typename... Ts>
Overloaded(Ts...) -> Overloaded<Ts...>;
void f() {
int x;
Overloaded o {
[&](this auto& self) {
return &x;
}
};
o();
}
```
To access `x` in the lambda, we need to perform derived-to-base
conversion on `self` (since the type of `self` is not the lambda type,
but rather `Overloaded<(lambda type)>`). We were previously missing this
step, causing us to attempt to load the entire lambda (as the base
class, it would end up being the ‘field’ with index `0` here), which
would then assert later on in codegen.
Moreover, this is only valid in the first place if there is a unique and
publicly accessible cast path from the derived class to the lambda’s
type, so this also adds a check in Sema to diagnose problematic
cases.
This fixes#87210 and fixes#89541.
The patch at https://reviews.llvm.org/D122732 introduced using the array
subscript operator for SVE vectors, however it also causes an ICE when
the subscripting expression is used as an lvalue.
This patches fixes the error. Lvalue subscripting expressions are
emitted as LLVM IR `insertelement`.
This is in effect a revert of f139ae3d93, as we have since gained a
more sophisticated way of doing extra IRGen with the addition of
RawAddress in #86923.
Latest diff:
f1ab4c2677..adf9bc902b
We address two additional bugs here:
### Problem 1: Deactivated normal cleanup still runs, leading to
double-free
Consider the following:
```cpp
struct A { };
struct B { B(const A&); };
struct S {
A a;
B b;
};
int AcceptS(S s);
void Accept2(int x, int y);
void Test() {
Accept2(AcceptS({.a = A{}, .b = A{}}), ({ return; 0; }));
}
```
We add cleanups as follows:
1. push dtor for field `S::a`
2. push dtor for temp `A{}` (used by ` B(const A&)` in `.b = A{}`)
3. push dtor for field `S::b`
4. Deactivate 3 `S::b`-> This pops the cleanup.
5. Deactivate 1 `S::a` -> Does not pop the cleanup as *2* is top. Should
create _active flag_!!
6. push dtor for `~S()`.
7. ...
It is important to deactivate **5** using active flags. Without the
active flags, the `return` will fallthrough it and would run both `~S()`
and dtor `S::a` leading to **double free** of `~A()`.
In this patch, we unconditionally emit active flags while deactivating
normal cleanups. These flags are deleted later by the `AllocaTracker` if
the cleanup is not emitted.
### Problem 2: Missing cleanup for conditional lifetime extension
We push 2 cleanups for lifetime-extended cleanup. The first cleanup is
useful if we exit from the middle of the expression (stmt-expr/coro
suspensions). This is deactivated after full-expr, and a new cleanup is
pushed, extending the lifetime of the temporaries (to the scope of the
reference being initialized).
If this lifetime extension happens to be conditional, then we use active
flags to remember whether the branch was taken and if the object was
initialized.
Previously, we used a **single** active flag, which was used by both
cleanups. This is wrong because the first cleanup will be forced to
deactivate after the full-expr and therefore this **active** flag will
always be **inactive**. The dtor for the lifetime extended entity would
not run as it always sees an **inactive** flag.
In this patch, we solve this using two separate active flags for both
cleanups. Both of them are activated if the conditional branch is taken,
but only one of them is deactivated after the full-expr.
---
Fixes https://github.com/llvm/llvm-project/issues/63818
Fixes https://github.com/llvm/llvm-project/issues/88478
---
Previous PR logs:
1. https://github.com/llvm/llvm-project/pull/85398
2. https://github.com/llvm/llvm-project/pull/88670
3. https://github.com/llvm/llvm-project/pull/88751
4. https://github.com/llvm/llvm-project/pull/88884
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.
The original change caused widespread breakages in msan/ubsan tests and
causes `use-after-free`. Most likely we are adding more cleanups than
necessary.
Fixes https://github.com/llvm/llvm-project/issues/63818 for control flow
out of an expressions.
#### Background
A control flow could happen in the middle of an expression due to
stmt-expr and coroutine suspensions.
Due to branch-in-expr, we missed running cleanups for the temporaries
constructed in the expression before the branch.
Previously, these cleanups were only added as `EHCleanup` during the
expression and as normal expression after the full expression.
Examples of such deferred cleanups include:
`ParenList/InitList`: Cleanups for fields are performed by the
destructor of the object being constructed.
`Array init`: Cleanup for elements of an array is included in the array
cleanup.
`Lifetime-extended temporaries`: reference-binding temporaries in
braced-init are lifetime extended to the parent scope.
`Lambda capture init`: init in the lambda capture list is destroyed by
the lambda object.
---
#### In this PR
In this PR, we change some of the `EHCleanups` cleanups to
`NormalAndEHCleanups` to make sure these are emitted when we see a
branch inside an expression (through statement expressions or coroutine
suspensions).
These are supposed to be deactivated after full expression and destroyed
later as part of the destructor of the aggregate or array being
constructed. To simplify deactivating cleanups, we add two utilities as
well:
* `DeferredDeactivationCleanupStack`: A stack to remember cleanups with
deferred deactivation.
* `CleanupDeactivationScope`: RAII for deactivating cleanups added to
the above stack.
---
#### Deactivating normal cleanups
These were previously `EHCleanups` and not `Normal` and **deactivation**
of **required** `Normal` cleanups had some bugs. These specifically
include deactivating `Normal` cleanups which are not the top of
`EHStack`
[source1](92b56011e6/clang/lib/CodeGen/CGCleanup.cpp (L1319)),
[2](92b56011e6/clang/lib/CodeGen/CGCleanup.cpp (L722-L746)).
This has not been part of our test suite (maybe it was never required
before statement expressions). In this PR, we also fix the emission of
required-deactivated-normal cleanups.
Fix since #75481 got reverted.
- Explicitly set BitfieldBits to 0 to avoid uninitialized field member
for the integer checks:
```diff
- llvm::ConstantInt::get(Builder.getInt8Ty(), Check.first)};
+ llvm::ConstantInt::get(Builder.getInt8Ty(), Check.first),
+ llvm::ConstantInt::get(Builder.getInt32Ty(), 0)};
```
- `Value **Previous` was erroneously `Value *Previous` in
`CodeGenFunction::EmitWithOriginalRHSBitfieldAssignment`, fixed now.
- Update following:
```diff
- if (Kind == CK_IntegralCast) {
+ if (Kind == CK_IntegralCast || Kind == CK_LValueToRValue) {
```
CK_LValueToRValue when going from, e.g., char to char, and
CK_IntegralCast otherwise.
- Make sure that `Value *Previous = nullptr;` is initialized (see
1189e87951)
- Add another extensive testcase
`ubsan/TestCases/ImplicitConversion/bitfield-conversion.c`
---------
Co-authored-by: Vitaly Buka <vitalybuka@gmail.com>
This patch fixes:
clang/lib/CodeGen/CGExpr.cpp:5607:11: error: variable 'Result' is
used uninitialized whenever 'if' condition is false
[-Werror,-Wsometimes-uninitialized]
This patch implements the implicit truncation and implicit sign change
checks for bitfields using UBSan. E.g.,
`-fsanitize=implicit-bitfield-truncation` and
`-fsanitize=implicit-bitfield-sign-change`.
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
To authenticate pointers, CodeGen needs access to the key and
discriminators that were used to sign the pointer. That information is
sometimes known from the context, but not always, which is why `Address`
needs to hold that information.
This patch adds methods and data members to `Address`, which will be
needed in subsequent patches to authenticate signed pointers, and uses
the newly added methods throughout CodeGen. Although this patch isn't
strictly NFC as it causes CodeGen to use different code paths in some
cases (e.g., `mergeAddressesInConditionalExpr`), it doesn't cause any
changes in functionality as it doesn't add any information needed for
authentication.
In addition to the changes mentioned above, this patch introduces class
`RawAddress`, which contains a pointer that we know is unsigned, and
adds several new functions for creating `Address` and `LValue` objects.
This reapplies d9a685a9dd, which was
reverted because it broke ubsan bots. There seems to be a bug in
coroutine code-gen, which is causing EmitTypeCheck to use the wrong
alignment. For now, pass alignment zero to EmitTypeCheck so that it can
compute the correct alignment based on the passed type (see function
EmitCXXMemberOrOperatorMemberCallExpr).
To authenticate pointers, CodeGen needs access to the key and
discriminators that were used to sign the pointer. That information is
sometimes known from the context, but not always, which is why `Address`
needs to hold that information.
This patch adds methods and data members to `Address`, which will be
needed in subsequent patches to authenticate signed pointers, and uses
the newly added methods throughout CodeGen. Although this patch isn't
strictly NFC as it causes CodeGen to use different code paths in some
cases (e.g., `mergeAddressesInConditionalExpr`), it doesn't cause any
changes in functionality as it doesn't add any information needed for
authentication.
In addition to the changes mentioned above, this patch introduces class
`RawAddress`, which contains a pointer that we know is unsigned, and
adds several new functions for creating `Address` and `LValue` objects.
This reapplies 8bd1f9116a. The commit
broke msan bots because LValue::IsKnownNonNull was uninitialized.
…i_check
This causes __cfi_check, just as __cfi_check_fail, to get the proper
target-specific attributes, in particular uwtable for unwind table
generation. Previously, nounwind attribute could be inferred for
__cfi_check, which caused it to lose its unwind table even with
-funwind-table option.
~~
Huawei RRI, OS Lab
Co-authored-by: Nikolai Kholiavin <kholiavin.nikolai@huawei-partners.com>
To authenticate pointers, CodeGen needs access to the key and
discriminators that were used to sign the pointer. That information is
sometimes known from the context, but not always, which is why `Address`
needs to hold that information.
This patch adds methods and data members to `Address`, which will be
needed in subsequent patches to authenticate signed pointers, and uses
the newly added methods throughout CodeGen. Although this patch isn't
strictly NFC as it causes CodeGen to use different code paths in some
cases (e.g., `mergeAddressesInConditionalExpr`), it doesn't cause any
changes in functionality as it doesn't add any information needed for
authentication.
In addition to the changes mentioned above, this patch introduces class
`RawAddress`, which contains a pointer that we know is unsigned, and
adds several new functions for creating `Address` and `LValue` objects.
In `-fbounds-safety`, bounds annotations are considered type attributes
rather than declaration attributes. Constructing them as type attributes
allows us to extend the attribute to apply nested pointers, which is
essential to annotate functions that involve out parameters: `void
foo(int *__counted_by(*out_count) *out_buf, int *out_count)`.
We introduce a new sugar type to support bounds annotated types,
`CountAttributedType`. In order to maintain extra data (the bounds
expression and the dependent declaration information) that is not
trackable in `AttributedType` we create a new type dedicate to this
functionality.
This patch also extends the parsing logic to parse the `counted_by`
argument as an expression, which will allow us to extend the model to
support arguments beyond an identifier, e.g., `__counted_by(n + m)` in
the future as specified by `-fbounds-safety`.
This also adjusts `__bdos` and array-bounds sanitizer code that already
uses `CountedByAttr` to check `CountAttributedType` instead to get the
field referred to by the attribute.
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 re-applies 30155fc0 with a fix for clangd.
### Description
clang don't evaluate the object argument of `static operator()` and
`static operator[]` currently, for example:
```cpp
#include <iostream>
struct Foo {
static int operator()(int x, int y) {
std::cout << "Foo::operator()" << std::endl;
return x + y;
}
static int operator[](int x, int y) {
std::cout << "Foo::operator[]" << std::endl;
return x + y;
}
};
Foo getFoo() {
std::cout << "getFoo()" << std::endl;
return {};
}
int main() {
std::cout << getFoo()(1, 2) << std::endl;
std::cout << getFoo()[1, 2] << std::endl;
}
```
`getFoo()` is expected to be called, but clang don't call it currently
(17.0.6). This PR fixes this issue.
Fixes#67976, reland #68485.
### Walkthrough
- **clang/lib/Sema/SemaOverload.cpp**
- **`Sema::CreateOverloadedArraySubscriptExpr` &
`Sema::BuildCallToObjectOfClassType`**
Previously clang generate `CallExpr` for static operators, ignoring the
object argument. In this PR `CXXOperatorCallExpr` is generated for
static operators instead, with the object argument as the first
argument.
- **`TryObjectArgumentInitialization`**
`const` / `volatile` objects are allowed for static methods, so that we
can call static operators on them.
- **clang/lib/CodeGen/CGExpr.cpp**
- **`CodeGenFunction::EmitCall`**
CodeGen changes for `CXXOperatorCallExpr` with static operators: emit
and ignore the object argument first, then emit the operator call.
- **clang/lib/AST/ExprConstant.cpp**
- **`ExprEvaluatorBase::handleCallExpr`**
Evaluation of static operators in constexpr also need some small changes
to work, so that the arguments won't be out of position.
- **clang/lib/Sema/SemaChecking.cpp**
- **`Sema::CheckFunctionCall`**
Code for argument checking also need to be modify, or it will fail the
test `clang/test/SemaCXX/overloaded-operator-decl.cpp`.
- **clang-tools-extra/clangd/InlayHints.cpp**
- **`InlayHintVisitor::VisitCallExpr`**
Now that the `CXXOperatorCallExpr` for static operators also have object
argument, we should also take care of this situation in clangd.
### Tests
- **Added:**
- **clang/test/AST/ast-dump-static-operators.cpp**
Verify the AST generated for static operators.
- **clang/test/SemaCXX/cxx2b-static-operator.cpp**
Static operators should be able to be called on const / volatile
objects.
- **Modified:**
- **clang/test/CodeGenCXX/cxx2b-static-call-operator.cpp**
- **clang/test/CodeGenCXX/cxx2b-static-subscript-operator.cpp**
Matching the new CodeGen.
### Documentation
- **clang/docs/ReleaseNotes.rst**
Update release notes.
---------
Co-authored-by: Shafik Yaghmour <shafik@users.noreply.github.com>
Co-authored-by: cor3ntin <corentinjabot@gmail.com>
Co-authored-by: Aaron Ballman <aaron@aaronballman.com>
### Description
clang don't evaluate the object argument of `static operator()` and
`static operator[]` currently, for example:
```cpp
#include <iostream>
struct Foo {
static int operator()(int x, int y) {
std::cout << "Foo::operator()" << std::endl;
return x + y;
}
static int operator[](int x, int y) {
std::cout << "Foo::operator[]" << std::endl;
return x + y;
}
};
Foo getFoo() {
std::cout << "getFoo()" << std::endl;
return {};
}
int main() {
std::cout << getFoo()(1, 2) << std::endl;
std::cout << getFoo()[1, 2] << std::endl;
}
```
`getFoo()` is expected to be called, but clang don't call it currently
(17.0.2). This PR fixes this issue.
Fixes#67976.
### Walkthrough
- **clang/lib/Sema/SemaOverload.cpp**
- **`Sema::CreateOverloadedArraySubscriptExpr` &
`Sema::BuildCallToObjectOfClassType`**
Previously clang generate `CallExpr` for static operators, ignoring the
object argument. In this PR `CXXOperatorCallExpr` is generated for
static operators instead, with the object argument as the first
argument.
- **`TryObjectArgumentInitialization`**
`const` / `volatile` objects are allowed for static methods, so that we
can call static operators on them.
- **clang/lib/CodeGen/CGExpr.cpp**
- **`CodeGenFunction::EmitCall`**
CodeGen changes for `CXXOperatorCallExpr` with static operators: emit
and ignore the object argument first, then emit the operator call.
- **clang/lib/AST/ExprConstant.cpp**
- **`ExprEvaluatorBase::handleCallExpr`**
Evaluation of static operators in constexpr also need some small changes
to work, so that the arguments won't be out of position.
- **clang/lib/Sema/SemaChecking.cpp**
- **`Sema::CheckFunctionCall`**
Code for argument checking also need to be modify, or it will fail the
test `clang/test/SemaCXX/overloaded-operator-decl.cpp`.
### Tests
- **Added:**
- **clang/test/AST/ast-dump-static-operators.cpp**
Verify the AST generated for static operators.
- **clang/test/SemaCXX/cxx2b-static-operator.cpp**
Static operators should be able to be called on const / volatile
objects.
- **Modified:**
- **clang/test/CodeGenCXX/cxx2b-static-call-operator.cpp**
- **clang/test/CodeGenCXX/cxx2b-static-subscript-operator.cpp**
Matching the new CodeGen.
### Documentation
- **clang/docs/ReleaseNotes.rst**
Update release notes.
---------
Co-authored-by: Shafik Yaghmour <shafik@users.noreply.github.com>
Co-authored-by: cor3ntin <corentinjabot@gmail.com>
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.
Previously committed as 9e08e51a20, and
reverted because a dependency commit was reverted, then committed again
as 4b574008ae and reverted again because
"dependency commit" 5a391d38ac was
reverted. But it doesn't seem that 5a391d38ac was a real dependency
for this.
This commit incorporates 4b574008ae and
18e093faf7 by Richard Smith (@zygoloid),
with some minor fixes, most notably:
- `UncommonValue` renamed to `StructuralValue`
- `VK_PRValue` instead of `VK_RValue` as default kind in lvalue and
member pointer handling branch in
`BuildExpressionFromNonTypeTemplateArgumentValue`;
- handling of `StructuralValue` in `IsTypeDeclaredInsideVisitor`;
- filling in `SugaredConverted` along with `CanonicalConverted`
parameter in `Sema::CheckTemplateArgument`;
- minor cleanup in
`TemplateInstantiator::transformNonTypeTemplateParmRef`;
- `TemplateArgument` constructors refactored;
- `ODRHash` calculation for `UncommonValue`;
- USR generation for `UncommonValue`;
- more correct MS compatibility mangling algorithm (tested on MSVC ver.
19.35; toolset ver. 143);
- IR emitting fixed on using a subobject as a template argument when the
corresponding template parameter is used in an lvalue context;
- `noundef` attribute and opaque pointers in `template-arguments` test;
- analysis for C++17 mode is turned off for templates in
`warn-bool-conversion` test; in C++17 and C++20 mode, array reference
used as a template argument of pointer type produces template argument
of UncommonValue type, and
`BuildExpressionFromNonTypeTemplateArgumentValue` makes
`OpaqueValueExpr` for it, and `DiagnoseAlwaysNonNullPointer` cannot see
through it; despite of "These cases should not warn" comment, I'm not
sure about correct behavior; I'd expect a suggestion to replace `if` by
`if constexpr`;
- `temp.arg.nontype/p1.cpp` and `dr18xx.cpp` tests fixed.
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;
}
```
