[Clang] CWG722: nullptr to ellipses (#104704)

https://cplusplus.github.io/CWG/issues/722.html

nullptr passed to a variadic function now converted to void* in C++.
This does not affect C23 nullpt

[Clang] CWG722: nullptr to ellipses (#104704)

https://cplusplus.github.io/CWG/issues/722.html

nullptr passed to a variadic function now converted to void* in C++.
This does not affect C23 nullptr.

Also fixes -Wformat-pedantic so that it no longer warns for nullptr
passed to %p (because it is converted to void* in C++ and it is allowed
for va_arg(ap, void*) in C23)

show more ...

[Sema] Implement support for -Wformat-signedness (#74440)

In gcc there exist a modifier option -Wformat-signedness that turns on
additional signedness warnings in the already existing -Wformat warn

[Sema] Implement support for -Wformat-signedness (#74440)

In gcc there exist a modifier option -Wformat-signedness that turns on
additional signedness warnings in the already existing -Wformat warning.

This patch implements that support in clang. This is done by adding a dummy
warning diag::warn_format_conversion_argument_type_mismatch_signedness that
is never emitted and only used as an option to toggle the signedness warning
in -Wformat. This will ensure gcc compatibility.

show more ...

[clang] Update -Wformat warnings for fixed-point format specifiers (#82855)

ISO/IEC TR 18037 defines %r, %R, %k, and %K for fixed point format
specifiers. -Wformat should not warn on these when the

[clang] Update -Wformat warnings for fixed-point format specifiers (#82855)

ISO/IEC TR 18037 defines %r, %R, %k, and %K for fixed point format
specifiers. -Wformat should not warn on these when they are provided.

show more ...

[Sema] Warning for _Float16 passed to format specifier '%f' (#74439)

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
default argument promotions for _FloatN types has been

[Sema] Warning for _Float16 passed to format specifier '%f' (#74439)

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.

Fixes: https://github.com/llvm/llvm-project/issues/68538

show more ...

[clang] Emit `Wformat` for bool value and char specifier confusion in scanf

Fixes https://github.com/llvm/llvm-project/issues/64987

Reviewed By: aaron.ballman

Differential Revision: https://review

[clang] Emit `Wformat` for bool value and char specifier confusion in scanf

Fixes https://github.com/llvm/llvm-project/issues/64987

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D159279

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[Sema] tolerate more promotion matches in format string checking

It's been reported that when using __attribute__((format)) on non-variadic
functions, certain values that normally get promoted when

[Sema] tolerate more promotion matches in format string checking

It's been reported that when using __attribute__((format)) on non-variadic
functions, certain values that normally get promoted when passed as variadic
arguments now unconditionally emit a diagnostic:

```c
void foo(const char *fmt, float f) __attribute__((format(printf, 1, 2)));
void bar(void) {
foo("%g", 123.f);
// ^ format specifies type 'double' but the argument has type 'float'
}
```

This is normally not an issue because float values get promoted to doubles when
passed as variadic arguments, but needless to say, variadic argument promotion
does not apply to non-variadic arguments.

While this can be fixed by adjusting the prototype of `foo`, this is sometimes
undesirable in C (for instance, if `foo` is ABI). In C++, using variadic
templates, this might instead require call-site fixing, which is tedious and
arguably needless work:

```c++
template<typename... Args>
void foo(const char *fmt, Args &&...args) __attribute__((format(printf, 1, 2)));
void bar(void) {
foo("%g", 123.f);
// ^ format specifies type 'double' but the argument has type 'float'
}
```

To address this issue, we teach FormatString about a few promotions that have
always been around but that have never been exercised in the direction that
FormatString checks for:

* `char`, `unsigned char` -> `int`, `unsigned`
* `half`, `float16`, `float` -> `double`

This addresses issue https://github.com/llvm/llvm-project/issues/59824.

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Diagnose incorrect use of scoped enumerations in format strings

Scoped enumerations in C++ do not undergo conversion to their
underlying type as part of default argument promotion, and so these
uses

Diagnose incorrect use of scoped enumerations in format strings

Scoped enumerations in C++ do not undergo conversion to their
underlying type as part of default argument promotion, and so these
uses are UB. GCC correctly diagnoses them, and now Clang matches.

Fixes https://github.com/llvm/llvm-project/issues/38717

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[Sema] -Wformat: recognize %lb for the printf/scanf family of functions

Fix https://github.com/llvm/llvm-project/issues/62247

D131057 added `bArg` and `BArg` in the `AsLongLong` label in
`FormatSpe

[Sema] -Wformat: recognize %lb for the printf/scanf family of functions

Fix https://github.com/llvm/llvm-project/issues/62247

D131057 added `bArg` and `BArg` in the `AsLongLong` label in
`FormatSpecifier::hasValidLengthModifier`, but missed the `AsLong` label,
therefore `%llb` is allowed while `%lb` (e.g. `printf("%lb", (long)10)`) has a
spurious warning. Add the missing case labels.

Reviewed By: aaron.ballman, enh

Differential Revision: https://reviews.llvm.org/D148779

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[clang] Use std::optional instead of llvm::Optional (NFC)

This patch replaces (llvm::|)Optional< with std::optional<. I'll post
a separate patch to remove #include "llvm/ADT/Optional.h".

This is p

[clang] Use std::optional instead of llvm::Optional (NFC)

This patch replaces (llvm::|)Optional< with std::optional<. I'll post
a separate patch to remove #include "llvm/ADT/Optional.h".

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

show more ...

[clang] Add #include <optional> (NFC)

This patch adds #include <optional> to those files containing
llvm::Optional<...> or Optional<...>.

I'll post a separate patch to actually replace llvm::Option

[clang] Add #include <optional> (NFC)

This patch adds #include <optional> to those files containing
llvm::Optional<...> or Optional<...>.

I'll post a separate patch to actually replace llvm::Optional with
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

show more ...

[AST] Use std::nullopt instead of None (NFC)

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of man

[AST] Use std::nullopt instead of None (NFC)

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

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[HLSL] Disable integer promotion to avoid int16_t being promoted to int for HLSL.

short will be promoted to int in UsualUnaryConversions.
Disable it for HLSL to keep int16_t as 16bit.

Reviewed By:

[HLSL] Disable integer promotion to avoid int16_t being promoted to int for HLSL.

short will be promoted to int in UsualUnaryConversions.
Disable it for HLSL to keep int16_t as 16bit.

Reviewed By: aaron.ballman, rjmccall

Differential Revision: https://reviews.llvm.org/D133668

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[clang][Sema] check default argument promotions for printf

The main focus of this patch is to make ArgType::matchesType check for
possible default parameter promotions when the argType is not a poin

[clang][Sema] check default argument promotions for printf

The main focus of this patch is to make ArgType::matchesType check for
possible default parameter promotions when the argType is not a pointer.
If so, no warning will be given for `int`, `unsigned int` types as
corresponding arguments to %hhd and %hd. However, the usage of %hhd
corresponding to short is relatively rare, and it is more likely to be a
misuse. This patch keeps the original behavior of clang like this as
much as possible, while making it more convenient to consider the
default arguments promotion.

Fixes https://github.com/llvm/llvm-project/issues/57102

Reviewed By: aaron.ballman, nickdesaulniers, #clang-language-wg

Differential Revision: https://reviews.llvm.org/D132568

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[clang] LLVM_FALLTHROUGH => [[fallthrough]]. NFC

With C++17 there is no Clang pedantic warning or MSVC C5051.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D131346

[Sema] -Wformat: support C23 format specifier %b %B

Close #56885: WG14 N2630 added %b to fprintf/fscanf and recommended %B for
fprintf. This patch teaches -Wformat %b for the printf/scanf family of

[Sema] -Wformat: support C23 format specifier %b %B

Close #56885: WG14 N2630 added %b to fprintf/fscanf and recommended %B for
fprintf. This patch teaches -Wformat %b for the printf/scanf family of functions
and %B for the printf family of functions.

glibc 2.35 and latest Android bionic added %b/%B printf support. From
https://www.openwall.com/lists/libc-coord/2022/07/ no scanf support is available
yet.

Like GCC, we don't test library support.

GCC 12 -Wformat -pedantic emits a warning:

> warning: ISO C17 does not support the ‘%b’ gnu_printf format [-Wformat=]

The behavior is not ported.

Note: `freebsd_kernel_printf` uses %b differently.

Reviewed By: aaron.ballman, dim, enh

Differential Revision: https://reviews.llvm.org/D131057

show more ...

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

---

Troubleshooting list to deal with any breakage seen with this patch:

1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.

2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.

3) This patch could expose a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.

4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.

5) It could be a bug in this patch perhaps.

Let me know if you need any help!

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it
stills breaks the LLDB tests. This was re-landed wi

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it
stills breaks the LLDB tests. This was re-landed without addressing the
issue or even agreement on how to address the issue. More details and
discussion in https://reviews.llvm.org/D112374.

show more ...

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

---

Troubleshooting list to deal with any breakage seen with this patch:

1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.

2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.

3) This patch could exposed a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.

4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.

5) It could be a bug in this patch perhaps.

Let me know if you need any help!

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it
breaks all the LLDB tests that import the std module

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it
breaks all the LLDB tests that import the std module.

import-std-module/array.TestArrayFromStdModule.py
import-std-module/deque-basic.TestDequeFromStdModule.py
import-std-module/deque-dbg-info-content.TestDbgInfoContentDequeFromStdModule.py
import-std-module/forward_list.TestForwardListFromStdModule.py
import-std-module/forward_list-dbg-info-content.TestDbgInfoContentForwardListFromStdModule.py
import-std-module/list.TestListFromStdModule.py
import-std-module/list-dbg-info-content.TestDbgInfoContentListFromStdModule.py
import-std-module/queue.TestQueueFromStdModule.py
import-std-module/stack.TestStackFromStdModule.py
import-std-module/vector.TestVectorFromStdModule.py
import-std-module/vector-bool.TestVectorBoolFromStdModule.py
import-std-module/vector-dbg-info-content.TestDbgInfoContentVectorFromStdModule.py
import-std-module/vector-of-vectors.TestVectorOfVectorsFromStdModule.py

https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/45301/

show more ...

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

Allow non-variadic functions to be attributed with `__attribute__((format))`

Clang only allows you to use __attribute__((format)) on variadic functions. There are legit use cases for __attribute__((

Allow non-variadic functions to be attributed with `__attribute__((format))`

Clang only allows you to use __attribute__((format)) on variadic functions. There are legit use cases for __attribute__((format)) on non-variadic functions, such as:

(1) variadic templates

```c++
template<typename… Args>
void print(const char *fmt, Args… &&args) __attribute__((format(1, 2))); // error: format attribute requires variadic function
```

(2) functions which take fixed arguments and a custom format:

```c++
void print_number_string(const char *fmt, unsigned number, const char *string) __attribute__((format(1, 2)));
// ^error: format attribute requires variadic function

void foo(void) {
print_number_string(“%08x %s\n”, 0xdeadbeef, “hello”);
print_number_string(“%d %s”, 0xcafebabe, “bar”);
}
```

This change allows Clang users to attach __attribute__((format)) to non-variadic functions, including functions with C++ variadic templates. It replaces the error with a GCC compatibility warning and improves the type checker to ensure that received arrays are treated like pointers (this is a possibility in C++ since references to template types can bind to arrays).

Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D112579
rdar://84629099

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[PS5] Support r and y specifiers of freebsd_kernel_printf format strings

[clang] Remove unused "using" (NFC)

[Sema] Emit a -Wformat warning for printf("%s", (void*)p)

Its dangerous to assume that the opaque pointer points to a null-terminated
string, and this has an easy fix (casting to char*).

rdar://624

[Sema] Emit a -Wformat warning for printf("%s", (void*)p)

Its dangerous to assume that the opaque pointer points to a null-terminated
string, and this has an easy fix (casting to char*).

rdar://62432331

show more ...

[AST] Use PrintingPolicy for format string diagnosis

Summary:
This is a small improvement for OpenCL diagnostics, but is also useful
for our CHERI fork, as our __capability qualifier is suppressed f

[AST] Use PrintingPolicy for format string diagnosis

Summary:
This is a small improvement for OpenCL diagnostics, but is also useful
for our CHERI fork, as our __capability qualifier is suppressed from
diagnostics when all pointers are capabilities, only being used when pointers
need to be explicitly opted-in to being capabilities.

Reviewers: rsmith, Anastasia, aaron.ballman

Reviewed By: Anastasia, aaron.ballman

Subscribers: aaron.ballman, arichardson, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D78777

show more ...