This is a follow-up to #132129.
Currently, only `Parser` and `SemaBase` get a `DiagCompat()` helper; I’m
planning to keep refactoring compatibility warnings and add more helpers
to other classes as needed. I also refactored a single parser compat
warning just to make sure everything works properly when diagnostics
across multiple components (i.e. Sema and Parser in this case) are
involved.
The combination of `-fcomplex-arithmetic=promoted` and `mno-x87` for
`double` complex division is leading to a crash.
See https://godbolt.org/z/189G957oY
This patch fixes that.
C2y adds the `_Countof` operator which returns the number of elements in
an array. As with `sizeof`, `_Countof` either accepts a parenthesized
type name or an expression. Its operand must be (of) an array type. When
passed a constant-size array operand, the operator is a constant
expression which is valid for use as an integer constant expression.
This is being exposed as an extension in earlier C language modes, but
not in C++. C++ already has `std::extent` and `std::size` to cover these
needs, so the operator doesn't seem to get the user enough benefit to
warrant carrying this as an extension.
Fixes#102836
The instantiation of a VarDecl's initializer might be deferred until the
variable is actually used. However, we were still building the
DeclRefExpr with a type that could later be changed by the initializer's
instantiation, which is incorrect when incomplete arrays are involved.
Fixes#79750Fixes#113936Fixes#133047
DenseSet, SmallPtrSet, SmallSet, SetVector, and StringSet recently
gained C++23-style insert_range. This patch replaces:
Dest.insert(Src.begin(), Src.end());
with:
Dest.insert_range(Src);
This patch does not touch custom begin like succ_begin for now.
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.
This introduces some tablegen helpers for defining compatibility
warnings. The main aim of this is to both simplify adding new
compatibility warnings as well as to unify the naming of compatibility
warnings.
I’ve refactored ~half of the compatiblity warnings (that follow the
usual scheme) in `DiagnosticSemaKinds.td` for illustration purposes and
also to simplify/unify the wording of some of them (I also corrected a
typo in one of them as a drive-by fix).
I haven’t (yet) migrated *all* warnings even in that one file, and there
are some more specialised ones for which the scheme I’ve established
here doesn’t work (e.g. because they’re warning+error instead of
warning+extwarn; however, warning+extension *is* supported), but the
point of this isn’t to implement *all* compatibility-related warnings
this way, only to make the common case a bit easier to handle.
This currently also only handles C++ compatibility warnings, but it
should be fairly straight-forward to extend the tablegen code so it can
also be used for C compatibility warnings (if this gets merged, I’m
planning to do that in a follow-up pr).
The vast majority of compatibility warnings are emitted by writing
```c++
Diag(Loc, getLangOpts().CPlusPlusYZ ? diag::ext_... : diag::warn_...)
```
in accordance with which I’ve chosen the following naming scheme:
```c++
Diag(Loc, getLangOpts().CPlusPlusYZ ? diag::compat_cxxyz_foo : diag::compat_pre_cxxyz_foo)
```
That is, for a warning about a C++20 feature—i.e. C++≤17
compatibility—we get:
```c++
Diag(Loc, getLangOpts().CPlusPlus20 ? diag::compat_cxx20_foo : diag::compat_pre_cxx20_foo)
```
While there is an argument to be made against writing ‘`compat_cxx20`’
here since is technically a case of ‘C++17 compatibility’ and not ‘C++20
compatibility’, I at least find this easier to reason about, because I
can just write the same number 3 times instead of having to use
`ext_cxx20_foo` but `warn_cxx17_foo`. Instead, I like to read this as a
warning about the ‘compatibility *of* a C++20 feature’ rather than
‘*with* C++17’.
I also experimented with moving all compatibility warnings to a separate
file, but 1. I don’t think it’s worth the effort, and 2. I think it
hurts compile times a bit because at least in my testing I felt that I
had to recompile more code than if we just keep e.g. Sema-specific
compat warnings in the Sema diagnostics file.
Instead, I’ve opted to put them all in the same place within any one
file; currently this is a the very top but I don’t really have strong
opinions about this.
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.
WG14 N2819 clarified that a compound literal within a function prototype
has a lifetime similar to that of a local variable within the function,
not a file scope variable.
Microsoft's compiler supports an extension for 128-bit literals. This is
referenced in `intsafe.h` which is included transitievly. When building
with modules, the literal parsing causes a failure due to the missing
support for the extension. To alleviate this issue, support parsing this
literal, especially now that there is the BitInt extension.
Take the opportunity to tighten up the code slightly by ensuring that we
do not access out-of-bounds characters when lexing the token.
It is still better to elide the declaration if possible. To overcome the
false positive undefinedButUsed diagnostic, it seems better to not add
declaration from other units to the set actually.
This clears up the printing of a NestedNameSpecifier so a trailing '::'
is not printed, unless it refers into the global scope.
This fixes a bunch of diagnostics where the trailing :: was awkward.
This also prints the NNS quoted consistenty.
There is a drive-by improvement to error recovery, where now we print
the actual type instead of `<dependent type>`.
This will clear up further uses of NNS printing in further patches.
This paper removes UB around use of void expressions. Previously, code
like this had undefined behavior:
```
void foo(void) {
(void)(void)1;
extern void x;
x;
}
```
and this is now well-defined in C2y. Functionally, this now means that
it is valid to use `void` as a `_Generic` association.
Fixes#28334
---
This PR introduces the `-Wshift-bool` warning to detect and warn against
shifting `bool` values using the `>>` operator. Shifting a `bool`
implicitly converts it to an `int`, which can lead to unintended
behavior.
This patch makes it so the correct instantiation context is printed for
diagnostics suppessed by template argument deduction.
The context is saved along with the suppressed diagnostic, and when the
declaration they were attached to becomes used, we print the correct
context, instead of whatever context was at this point.
When a statement expression's last statement is an atomic variable, GCC
and Clang disagree on the type of the expression. This can be made
apparent using `typeof` and forcing a diagnostic message:
```cpp
_Atomic int a = 0;
typeof(({a;})) x = "0";
```
* GCC complains about initializing `int` with `char*`
* Clang complains about initializing `_Atomic(int)` with a `char[2]`
Due to the type of the statement expression being deduced to be atomic,
we end with three implicit casts inside the `StmtExpr` on the AST:
* `LValueToRValue` -> `AtomicToNonAtomic` -> `NonAtomicToAtomic`
In some situations, this can end on an assertion inside
`IntExprEvaluator`, as reported in #106576.
With this patch, we now have two implicit casts, since the type of the
statement expression is deduced to be non-atomic:
* `LValueToRValue` -> `AtomicToNonAtomic`
This is consistent with the C standard (6.7.2.4, p4)
> The properties associated with atomic types are meaningful only for
expressions that are lvalues.
But a statement expression is an rvalue.
`IntExprEvaluator` assumptions are now satisfied and there is no
assertion error.
Additionally, the `typeof` trick mentioned above shows that the type is
consistently deduced between GCC and Clang.
Fixes#106576
---------
Co-authored-by: John McCall <rjmccall@gmail.com>
This merges the functionality of ResolvedUnexpandedPackExpr into
FunctionParmPackExpr. I also added a test to show that
https://github.com/llvm/llvm-project/issues/125103 should be fixed with
this. I put the removal of ResolvedUnexpandedPackExpr in its own commit.
Let me know what you think.
Fixes#125103
This PR reapply https://github.com/llvm/llvm-project/pull/117437.
The issue has been fixed by the 2nd commit, we need to ignore parens in
CXXDefaultArgExpr when build CFG, because CXXDefaultArgExpr::getExpr
stripped off the top level FullExpr and ConstantExpr, ParenExpr may
occurres in the top level.
---------
Signed-off-by: yronglin <yronglin777@gmail.com>
This both reapplies #118734, the initial attempt at this, and updates it
significantly.
First, it uses the newly added `StringTable` abstraction for string
tables, and simplifies the construction to build the string table and
info arrays separately. This should reduce any `constexpr` compile time
memory or CPU cost of the original PR while significantly improving the
APIs throughout.
It also restructures the builtins to support sharding across several
independent tables. This accomplishes two improvements from the
original PR:
1) It improves the APIs used significantly.
2) When builtins are defined from different sources (like SVE vs MVE in
AArch64), this allows each of them to build their own string table
independently rather than having to merge the string tables and info
structures.
3) It allows each shard to factor out a common prefix, often cutting the
size of the strings needed for the builtins by a factor two.
The second point is important both to allow different mechanisms of
construction (for example a `.def` file and a tablegen'ed `.inc` file,
or different tablegen'ed `.inc files), it also simply reduces the sizes
of these tables which is valuable given how large they are in some
cases. The third builds on that size reduction.
Initially, we use this new sharding rather than merging tables in
AArch64, LoongArch, RISCV, and X86. Mostly this helps ensure the system
works, as without further changes these still push scaling limits.
Subsequent commits will more deeply leverage the new structure,
including using the prefix capabilities which cannot be easily factored
out here and requires deep changes to the targets.
This caused assertion failures:
clang/lib/Analysis/CFG.cpp:822:
void (anonymous namespace)::CFGBuilder::appendStmt(CFGBlock *, const Stmt *):
Assertion `!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S' failed.
See comment on the PR.
This reverts commit 44aa618ef67d302f5ab77cc591fb3434fe967a2e.
This commit restricts the use of scalar types in vector math builtins,
particularly the `__builtin_elementwise_*` builtins.
Previously, small scalar integer types would be promoted to `int`, as
per the usual conversions. This would silently do the wrong thing for
certain operations, such as `add_sat`, `popcount`, `bitreverse`, and
others. Similarly, since unsigned integer types were promoted to `int`,
something like `add_sat(unsigned char, unsigned char)` would perform a
*signed* operation.
With this patch, promotable scalar integer types are not promoted to
int, and are kept intact. If any of the types differ in the binary and
ternary builtins, an error is issued. Similarly an error is issued if
builtins are supplied integer types of different signs. Mixing enums of
different types in binary/ternary builtins now consistently raises an
error in all language modes.
This brings the behaviour surrounding scalar types more in line with
that of vector types. No change is made to vector types, which are both
not promoted and whose element types must match.
Fixes#84047.
RFC:
https://discourse.llvm.org/t/rfc-change-behaviour-of-elementwise-builtins-on-scalar-integer-types/83725
GCC supports three flags related to overflow behavior:
* `-fwrapv`: Makes signed integer overflow well-defined.
* `-fwrapv-pointer`: Makes pointer overflow well-defined.
* `-fno-strict-overflow`: Implies `-fwrapv -fwrapv-pointer`, making both
signed integer overflow and pointer overflow well-defined.
Clang currently only supports `-fno-strict-overflow` and `-fwrapv`, but
not `-fwrapv-pointer`.
This PR proposes to introduce `-fwrapv-pointer` and adjust the semantics
of `-fwrapv` to match GCC.
This allows signed integer overflow and pointer overflow to be
controlled independently, while `-fno-strict-overflow` still exists to
control both at the same time (and that option is consistent across GCC
and Clang).
HandleImmediateInvocation can call MarkExpressionAsImmediateEscalating
and should always be called before
CheckImmediateEscalatingFunctionDefinition.
However, we were not doing that in `ActFunctionBody`.
We simply move CheckImmediateEscalatingFunctionDefinition to
PopExpressionEvaluationContext.
Fixes#119046
Reimplement Neon FP8 vector types using attribute `neon_vector_type`
instead of having them as builtin types.
This allows to implement FP8 Neon intrinsics without the need to add
special cases for these types when using `__builtin_shufflevector`
or bitcast (using C-style cast operator) between vectors, both
extensively used in the generated code in `arm_neon.h`.
In addition to the invocation case that is already diagnosed, also
diagnose when a block reference appears on either side of a ternary
selection operator.
Until now, clang would accept the added test case only to crash during
code generation.
It turns out that the substitution for expression comparing also needs
an unevaluated context, otherwise any reference to immediate functions
might not be properly handled.
As a fallout, this also guards the VLA transformation under unevaluated
context
with `InConditionallyConstantEvaluateContext` to avoid duplicate
diagnostics.
Fixes https://github.com/llvm/llvm-project/issues/123472
---------
Co-authored-by: cor3ntin <corentinjabot@gmail.com>
Closes#119360.
This bug occurs when passing a VLA to `va_arg`. Since the return value
is inferred to be an array, it triggers
`ScalarExprEmitter::VisitCastExpr`, which converts it to a pointer and
subsequently calls `CodeGenFunction::EmitAggExpr`. At this point,
because the inferred type is an `AggExpr` instead of a `ScalarExpr`,
`ScalarExprEmitter::VisitVAArgExpr` is not invoked, and as a result,
`CodeGenFunction::EmitVariablyModifiedType` is also not called, leading
to the size of the VLA not being retrieved.
The solution is to move the call to
`CodeGenFunction::EmitVariablyModifiedType` into
`CodeGenFunction::EmitVAArg`, ensuring that the size of the VLA is
correctly obtained regardless of whether the expression is an `AggExpr`
or a `ScalarExpr`.
For structured bindings, a call to getCapturedDeclRefType(...) was
missing. This PR fixes that behavior and adds the related diagnostics
too.
This fixes https://github.com/llvm/llvm-project/issues/95081.
This diagnoses comparisons like `ptr + unsigned_index < ptr` and `ptr +
unsigned_index >= ptr`, which are always false/true because addition of
a pointer and an unsigned index cannot wrap (or the behavior is
undefined).
This warning is intended to help find broken bounds checks (which must
be implemented in terms of uintptr_t instead).
Fixes https://github.com/llvm/llvm-project/issues/120214.
For a FunctionParmPackExpr that is used as the argument of a
sizeof...(pack) expression, we might exercise the logic that checks the
CXXRecordDecl's members regardless of the type being incomplete, when
rebuilding the DeclRefExpr into non-ODR-used forms.
Fixes https://github.com/llvm/llvm-project/issues/81436
Currently, we support `-wdeprecated-array-compare` for C++20 or above
and don't report any warning for older versions, this PR supports
`-Warray-compare` for older versions and for GCC compatibility.
Fixes#114770
This aligns with the logic in `TreeTransform::RebuildQualifiedType()`
where we refrain from adding const qualifiers to function types.
Previously, we seemed to overlook this edge case when copy-capturing a
variable that is of function type within a const-qualified lambda.
This issue also reveals other related problems as in incorrect type
printout and a suspicious implementation in DeduceTemplateArguments. I
decide to leave them in follow-up work.
Fixes#84961
