This is a major change on how we represent nested name qualifications in
the AST.
* The nested name specifier itself and how it's stored is changed. The
prefixes for types are handled within the type hierarchy, which makes
canonicalization for them super cheap, no memory allocation required.
Also translating a type into nested name specifier form becomes a no-op.
An identifier is stored as a DependentNameType. The nested name
specifier gains a lightweight handle class, to be used instead of
passing around pointers, which is similar to what is implemented for
TemplateName. There is still one free bit available, and this handle can
be used within a PointerUnion and PointerIntPair, which should keep
bit-packing aficionados happy.
* The ElaboratedType node is removed, all type nodes in which it could
previously apply to can now store the elaborated keyword and name
qualifier, tail allocating when present.
* TagTypes can now point to the exact declaration found when producing
these, as opposed to the previous situation of there only existing one
TagType per entity. This increases the amount of type sugar retained,
and can have several applications, for example in tracking module
ownership, and other tools which care about source file origins, such as
IWYU. These TagTypes are lazily allocated, in order to limit the
increase in AST size.
This patch offers a great performance benefit.
It greatly improves compilation time for
[stdexec](https://github.com/NVIDIA/stdexec). For one datapoint, for
`test_on2.cpp` in that project, which is the slowest compiling test,
this patch improves `-c` compilation time by about 7.2%, with the
`-fsyntax-only` improvement being at ~12%.
This has great results on compile-time-tracker as well:
This patch also further enables other optimziations in the future, and
will reduce the performance impact of template specialization resugaring
when that lands.
It has some other miscelaneous drive-by fixes.
About the review: Yes the patch is huge, sorry about that. Part of the
reason is that I started by the nested name specifier part, before the
ElaboratedType part, but that had a huge performance downside, as
ElaboratedType is a big performance hog. I didn't have the steam to go
back and change the patch after the fact.
There is also a lot of internal API changes, and it made sense to remove
ElaboratedType in one go, versus removing it from one type at a time, as
that would present much more churn to the users. Also, the nested name
specifier having a different API avoids missing changes related to how
prefixes work now, which could make existing code compile but not work.
How to review: The important changes are all in
`clang/include/clang/AST` and `clang/lib/AST`, with also important
changes in `clang/lib/Sema/TreeTransform.h`.
The rest and bulk of the changes are mostly consequences of the changes
in API.
PS: TagType::getDecl is renamed to `getOriginalDecl` in this patch, just
for easier to rebasing. I plan to rename it back after this lands.
Fixes#136624
Fixes https://github.com/llvm/llvm-project/issues/43179
Fixes https://github.com/llvm/llvm-project/issues/68670
Fixes https://github.com/llvm/llvm-project/issues/92757
Fix access and ambiguity checks not being performed when converting to
an rvalue reference to a base class type with `static_cast`.
Fixes#121429
---------
Co-authored-by: Corentin Jabot <corentinjabot@gmail.com>
This removes the workaround introduced in 3e1a9cf3b8 and 1ba7dc38d.
The workaround overwrote the right parenthesis location of the sub
expression, which could be wrong when a CXXTemporaryObjectExpr occurs
within a nested expression, e.g. `A(A(1, 2))`.
To completely take it down, we now propagate the left parenthesis source
location throughout SemaCast, such that the ParenOrBraceRange can be
properly set at the point of its creation.
Fixes https://github.com/llvm/llvm-project/issues/143711
The qualifier allows programmer to directly control how pointers are
signed when they are stored in a particular variable.
The qualifier takes three arguments: the signing key, a flag specifying
whether address discrimination should be used, and a non-negative
integer that is used for additional discrimination.
```
typedef void (*my_callback)(const void*);
my_callback __ptrauth(ptrauth_key_process_dependent_code, 1, 0xe27a) callback;
```
Co-Authored-By: John McCall rjmccall@apple.com
On Windows, GetProcAddress() is the API used to dynamically load
function pointers (similar to dlsym on Linux). This API returns a
function pointer (a typedef named FARPROC), which means that casting
from the call to the eventual correct type is technically a function
type mismatch on the cast. However, because this is idiomatic code on
Windows, we should accept it unless -Wcast-function-type-strict is
passed.
This was brought up in post-commit review feedback on
https://github.com/llvm/llvm-project/pull/86131
Original PR: #130537
Originally reverted due to revert of dependent commit. Relanding with no
changes.
This changes the MemberPointerType representation to use a
NestedNameSpecifier instead of a Type to represent the base class.
Since the qualifiers are always parsed as nested names, there was an
impedance mismatch when converting these back and forth into types, and
this led to issues in preserving sugar.
The nested names are indeed a better match for these, as the differences
which a QualType can represent cannot be expressed syntatically, and
they represent the use case more exactly, being either dependent or
referring to a CXXRecord, unqualified.
This patch also makes the MemberPointerType able to represent sugar for
a {up/downcast}cast conversion of the base class, although for now the
underlying type is canonical, as preserving the sugar up to that point
requires further work.
As usual, includes a few drive-by fixes in order to make use of the
improvements.
Original PR: #130537
Reland after updating lldb too.
This changes the MemberPointerType representation to use a
NestedNameSpecifier instead of a Type to represent the base class.
Since the qualifiers are always parsed as nested names, there was an
impedance mismatch when converting these back and forth into types, and
this led to issues in preserving sugar.
The nested names are indeed a better match for these, as the differences
which a QualType can represent cannot be expressed syntatically, and
they represent the use case more exactly, being either dependent or
referring to a CXXRecord, unqualified.
This patch also makes the MemberPointerType able to represent sugar for
a {up/downcast}cast conversion of the base class, although for now the
underlying type is canonical, as preserving the sugar up to that point
requires further work.
As usual, includes a few drive-by fixes in order to make use of the
improvements.
This changes the MemberPointerType representation to use a
NestedNameSpecifier instead of a Type to represent the class.
Since the qualifiers are always parsed as nested names, there was an
impedance mismatch when converting these back and forth into types, and
this led to issues in preserving sugar.
The nested names are indeed a better match for these, as the differences
which a QualType can represent cannot be expressed syntactically, and it
also represents the use case more exactly, being either dependent or
referring to a CXXRecord, unqualified.
This patch also makes the MemberPointerType able to represent sugar for
a {up/downcast}cast conversion of the base class, although for now the
underlying type is canonical, as preserving the sugar up to that point
requires further work.
As usual, includes a few drive-by fixes in order to make use of the
improvements, and removing some duplications, for example
CheckBaseClassAccess is deduplicated from across SemaAccess and
SemaCast.
This change allows array variables to copy-initialize from other arrays.
It also corrects a small error in HLSL C-Style casting that did not
error on casting to arrays if elementwise and splat conversions fail.
Fixes#127551
Implement HLSL Aggregate Splat casting that handles splatting for arrays
and structs, and vectors if splatting from a vec1.
Closes#100609 and Closes#100619
Depends on #118842
Implement HLSLElementwiseCast excluding support for splat cases
Do not support casting types that contain bitfields.
Partly closes#100609 and partly closes#100619
After 1595988ee6f9732e7ea79928af8a470ad5ef7dbe
diag::warn_undefined_reinterpret_cast started raising on
non-instantiated template functions without sufficient knowledge whether
the reinterpret_cast is indeed UB.
Summary:
Address spaces are used in several embedded and GPU targets to describe
accesses to different types of memory. Currently we use the address
space enumerations to control which address spaces are considered
supersets of eachother, however this is also a target level property as
described by the C standard's passing mentions. This patch allows the
address space checks to use the target information to decide if a
pointer conversion is legal. For AMDGPU and NVPTX, all supported address
spaces can be converted to the default address space.
More semantic checks can be added on top of this, for now I'm mainly
looking to get more standard semantics working for C/C++. Right now the
address space conversions must all be done explicitly in C/C++ unlike
the offloading languages which define their own custom address spaces
that just map to the same target specific ones anyway. The main question
is if this behavior is a function of the target or the language.
Fixed an assertion failure in debug mode, and potential crashes in
release mode, when
diagnosing a failed cast caused indirectly by a failed implicit
conversion to the type of the constructor parameter.
For instance
```
template<typename>
struct StringTrait {};
template< int N >
struct StringTrait< const char[ N ] > {
typedef char CharType;
static const MissingIntT length = N - 1;
};
class String {
public:
template <typename T>
String(T& str, typename StringTrait<T>::CharType = 0);
};
class Exception {
public:
Exception(String const&);
};
void foo() {
throw Exception("some error");
}
```
`Exception(String const&)` is a matching constructor for `Exception`
from a `const char*`, via an implicit conversion to `String`. However,
the instantiation of the `String` constructor will fail because of the
missing type `MissingIntT` inside the specialization of `StringTrait`.
When trying to emit a diagnosis, `tryDiagnoseOverloadedCast` expects not
to have a matching constructor, but there is; it just could not be
instantiated.
The primary motivation behind this is to allow the enum type to be
referred to earlier in the Sema.h file which is needed for #106321.
It was requested in #106321 that a scoped enum be used (rather than
moving the enum declaration earlier in the Sema class declaration).
Unfortunately doing this creates a lot of churn as all use sites of the
enum constants had to be changed. Appologies to all downstream forks in
advanced.
Note the AA_ prefix has been dropped from the enum value names as they
are now redundant.
This patch moves documentation of `Sema` functions from `.cpp` files to `Sema.h` when there was no documentation in the latter, or it can be trivially subsumed. More complicated cases when there's less trivial divergence between documentation attached to declaration and the one attached to implementation are left for a later PR that would require review.
It appears that doxygen can find the documentation for a function defined out-of-line even if it's attached to an implementation, and not declaration. But other tools, e.g. clangd, are not as powerful. So this patch significantly improves autocompletion experience for (at least) clangd-based IDEs.
Enums are passed as their underlying integral type so they're ABI compatible if the size matches.
Useful with C APIs that pass user-controlled values to callbacks that can be made type safe by using enumerations (e.g. GStreamer).
Discovered internally in some code after 999d4f840777bf8de26d45947192aa0728edc0fb.
This patch moves `Sema` functions that are specific for RISC-V into the
new `SemaRISCV` class. This continues previous efforts to split `Sema`
up. Additional context can be found in
https://github.com/llvm/llvm-project/pull/84184.
This PR is somewhat different from previous PRs on this topic:
1. Splitting out target-specific functions wasn't previously discussed.
It felt quite natural to do, though.
2. I had to make some static function in `SemaChecking.cpp` member
functions of `Sema` in order to use them in `SemaRISCV`.
3. I dropped "RISCV" from identifiers, but decided to leave "RVV"
(RISC-V "V" vector extensions) intact. I think it's an idiomatic
abbreviation at this point, but I'm open to input from contributors in
that area.
4. I repurposed `SemaRISCVVectorLookup.cpp` for `SemaRISCV`.
I think this was a successful experiment, which both helps the goal of
splitting `Sema` up, and shows a way to approach `SemaChecking.cpp`,
which I wasn't sure how to approach before. As we move more
target-specific function out of there, we'll gradually make the checking
"framework" inside `SemaChecking.cpp` public, which is currently a whole
bunch of static functions. This would enable us to move more functions
outside of `SemaChecking.cpp`.
Set the correct end for the CastOperation.OpRange in CXXFunctionalCastExpr.
Now it is the closing bracket's location instead of the parameter's location.
This can lead to better highlight in the diagnostics.
Similar to https://github.com/llvm/llvm-project/pull/66853
Before:
warning: cast from 'long (*)(const int &)' to 'decltype(fun_ptr)' (aka 'long (*)(int &)') converts to incompatible function type [-Wcast-function-type-strict]
24 | return decltype(fun_ptr)( f_ptr /*comment*/);
| ^~~~~~~~~~~~~~~~~~~~~~~~
After:
warning: cast from 'long (*)(const int &)' to 'decltype(fun_ptr)' (aka 'long (*)(int &)') converts to incompatible function type [-Wcast-function-type-strict]
24 | return decltype(fun_ptr)( f_ptr /*comment*/);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Reviewed By: AaronBallman, tbaederr
GitHub PR: https://github.com/llvm/llvm-project/pull/69480
Functional-style cast (i.e. a simple-type-specifier or typename-specifier
followed by a parenthesize single expression [expr.type.conv]) is equivalent
to the C-style cast, so that makes sense they have identical behavior
including warnings.
This also matches GCC https://godbolt.org/z/b8Ma9Thjb.
Reviewed By: rnk, aaron.ballman
Differential Revision: https://reviews.llvm.org/D159133
This does the rename for most internal uses of C2x, but does not rename
or reword diagnostics (those will be done in a follow-up).
I also updated standards references and citations to the final wording
in the standard.
In C++20, if Clang fails to perform constructor overload on a
RecordType, then Clang will try to perform parentesized aggregate
initialization. If that fails and the initialization was attempted as
part of a cast, then we should get the diagnostics from the failed
constructor overload attempt. However, we don't attempt constructor
overloading for arrays, so previously, if we try to diagnose an
overloaded cast for a parenthesized aggregate initialization of an
array, we crash. To fix this, we now exit tryDiagnoseOverloadedCast(...)
for failed parentesized list initialization if the destination type is
an array.
Fixes#63758
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D155523
In preparation for removing the `#include "llvm/ADT/StringExtras.h"`
from the header to source file of `llvm/Support/Error.h`, first add in
all the missing includes that were previously included transitively
through this header.
This commit implements support for WebAssembly table types and
respective builtins. Table tables are WebAssembly objects to store
reference types. They have a large amount of semantic restrictions
including, but not limited to, only being allowed to be declared
at the top-level as static arrays of zero-length. Not being arguments
or result of functions, not being stored ot memory, etc.
This commit introduces the __attribute__((wasm_table)) to attach to
arrays of WebAssembly reference types. And the following builtins to
manage tables:
* ref __builtin_wasm_table_get(table, idx)
* void __builtin_wasm_table_set(table, idx, ref)
* uint __builtin_wasm_table_size(table)
* uint __builtin_wasm_table_grow(table, ref, uint)
* void __builtin_wasm_table_fill(table, idx, ref, uint)
* void __builtin_wasm_table_copy(table, table, uint, uint, uint)
This commit also enables reference-types feature at bleeding-edge.
This is joint work with Alex Bradbury (@asb).
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D139010
Pursuant to discussions at
https://discourse.llvm.org/t/rfc-c-23-p1467r9-extended-floating-point-types-and-standard-names/70033/22,
this commit enhances the handling of the __bf16 type in Clang.
- Firstly, it upgrades __bf16 from a storage-only type to an arithmetic
type.
- Secondly, it changes the mangling of __bf16 to DF16b on all
architectures except ARM. This change has been made in
accordance with the finalization of the mangling for the
std::bfloat16_t type, as discussed at
https://github.com/itanium-cxx-abi/cxx-abi/pull/147.
- Finally, this commit extends the existing excess precision support to
the __bf16 type. This applies to hardware architectures that do not
natively support bfloat16 arithmetic.
Appropriate tests have been added to verify the effects of these
changes and ensure no regressions in other areas of the compiler.
Reviewed By: rjmccall, pengfei, zahiraam
Differential Revision: https://reviews.llvm.org/D150913
This allows the user to set the size of the scalable vector so they
can be used in structs and as the type of global variables. This works
by representing the type as a fixed vector instead of a scalable vector
in IR. Conversions to and from scalable vectors are made where necessary
like function arguments/returns and intrinsics.
This features has been requested here
https://github.com/riscv-non-isa/rvv-intrinsic-doc/issues/176
I know arm_sve_vector_bits is used by the Eigen library so this
could be used to port Eigen to RVV.
This patch adds a new preprocessor define `__riscv_v_fixed_vlen` that
is set when -mrvv_vector_bits is passed on the command line.
The code is largely based on the AArch64 code. A lot of code was
copy/pasted and then modiied to RVV. There may be some opportunities
for sharing.
This first patch only supports the LMUL=1 types. Additional changes
will be needed to support other LMULs. I have also not supported
mask vectors.
Differential Revision: https://reviews.llvm.org/D145088
-Wcast-qual does not trigger on the following code in Clang, but does
in GCC.
const auto i = 42;
using T = int*;
auto p = T(&i);
The expected behavior is that a functional cast should trigger
the warning the same as the equivalent C cast because
the meaning is the same, and nothing about the functional cast
makes it easier to recognize that a const_cast is occurring.
Fixes https://github.com/llvm/llvm-project/issues/62083
Differential Revision: https://reviews.llvm.org/D148276
We were failing to strip off atomic qualification when forming the cast
destination type, but properly stripping off cvr qualification. Now we
accept atomic, qualified, or unqualified destination types.
Note: the semantics of the cast still drop the qualifier, so such a
cast does not result in an atomic rvalue.
Fixes https://github.com/llvm/llvm-project/issues/39596
This commit relands the patches for implementing P0960R3 and P1975R0,
which describe initializing aggregates via a parenthesized list.
The relanded commits are:
* 40c52159d3ee - P0960R3 and P1975R0: Allow initializing aggregates from
a parenthesized list of values
* c77a91bb7ba7 - Remove overly restrictive aggregate paren init logic
* 32d7aae04fdb - Fix a clang crash on invalid code in C++20 mode
This patch also fixes a crash in the original implementation.
Previously, if the input tried to call an implicitly deleted copy or
move constructor of a union, we would then try to initialize the union
by initializing it's first element with a reference to a union. This
behavior is incorrect (we should fail to initialize) and if the type of
the first element has a constructor with a single template typename
parameter, then Clang will explode. This patch fixes that issue by
checking that constructor overload resolution did not result in a
deleted function before attempting parenthesized aggregate
initialization.
Additionally, this patch also includes D140159, which contains some
minor fixes made in response to code review comments in the original
implementation that were made after that patch was submitted.
Co-authored-by: Sheng <ox59616e@gmail.com>
Fixes#54040, Fixes#59675
Reviewed By: ilya-biryukov
Differential Revision: https://reviews.llvm.org/D141546
This feature causes clang to crash when compiling Chrome - see
https://crbug.com/1405031 and
https://github.com/llvm/llvm-project/issues/59675
Revert "[clang] Fix a clang crash on invalid code in C++20 mode."
This reverts commit 32d7aae04fdb58e65a952f281ff2f2c3f396d98f.
Revert "[clang] Remove overly restrictive aggregate paren init logic"
This reverts commit c77a91bb7ba793ec3a6a5da3743ed55056291658.
Revert "[clang][C++20] P0960R3 and P1975R0: Allow initializing aggregates from a parenthesized list of values"
This reverts commit 40c52159d3ee337dbed14e4c73b5616ea354c337.
This patch implements P0960R3, which allows initialization of aggregates
via parentheses.
As an example:
```
struct S { int i, j; };
S s1(1, 1);
int arr1[2](1, 2);
```
This patch also implements P1975R0, which fixes the wording of P0960R3
for single-argument parenthesized lists so that statements like the
following are allowed:
```
S s2(1);
S s3 = static_cast<S>(1);
S s4 = (S)1;
int (&&arr2)[] = static_cast<int[]>(1);
int (&&arr3)[2] = static_cast<int[2]>(1);
```
This patch was originally authored by @0x59616e and completed by
@ayzhao.
Fixes#54040, Fixes#54041
Co-authored-by: Sheng <ox59616e@gmail.com>
Full write up : https://discourse.llvm.org/t/c-20-rfc-suggestion-desired-regarding-the-implementation-of-p0960r3/63744
Reviewed By: ilya-biryukov
Differential Revision: https://reviews.llvm.org/D129531
Clang supports indirect call Control-Flow Integrity (CFI) sanitizers
(e.g. -fsanitize=cfi-icall), which enforce an exact type match between
a function pointer and the target function. Unfortunately, Clang
doesn't provide diagnostics that would help developers avoid function
type casts that lead to runtime CFI failures. -Wcast-function-type,
while helpful, only warns about ABI incompatibility, which isn't
sufficient with CFI.
Add -Wcast-function-type-strict, which checks for a strict type
compatibility in function type casts and helps warn about casts that
can potentially lead to CFI failures.
Reviewed By: nickdesaulniers, aaron.ballman
Differential Revision: https://reviews.llvm.org/D134831
