While discussing diagnostic format strings with a GSoC mentee, it
became clear there was some confusion regarding how to use them.
Specifically, the documentation for %select caused confunsion because
it was using %select{}2 and talking about how the integer value must
be in the range [0..2], which made it seem like the positional argument
was actually specifying the range of acceptable values.
I clarified several of the examples similarly, moved some documentation
to a more appropriate place, and added some additional information to
the %s modifier to point out that %plural exists.
We get some standard C++ module things done in clang15.x. But we lack a
user documentation for it. The implementation of standard C++ modules
share a big part of codes with clang modules. But they have very
different semantics and user interfaces, so I think it is necessary to
add a document for Standard C++ modules. Previously, there were also
some people ask the document for standard C++ Modules and I couldn't
offer that time.
Reviewed By: iains, Mordante, h-vetinari, ruoso, dblaikie, JohelEGP,
aaronmondal
Differential Revision: https://reviews.llvm.org/D131388
In Sema::CheckCompletedCXXClass(...) It used a lambda CheckForDefaultedFunction
the CXXMethodDecl passed to CheckForDefaultedFunction may not be a special
member function and so before attempting to apply functions that only apply to
special member functions it needs to check. It fails to do this before calling
DefineDefaultedFunction(...). This PR adds that check and test to verify we no
longer crash.
This fixes https://github.com/llvm/llvm-project/issues/57431
Differential Revision: https://reviews.llvm.org/D132906
This document describes the basic usage and implementation details for
HLSL entry functions in Clang.
Reviewed By: python3kgae
Differential Revision: https://reviews.llvm.org/D132672
When checking parameter packs for expansion, instead of basing the diagnostic for
length mismatch for outer parameters only on the known number of expansions,
we should also analyze SubstTemplateTypeParmPackType and SubstNonTypeTemplateParmPackExpr
for unexpanded packs, so we can emit a diagnostic pointing to a concrete
outer parameter.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D128095
Summary:
Some of code in the patch are contributed by David Tenty.
1. We currently only check driver Wl options and don't check for the plain -b, -Xlinker or other options which get passed through to the linker when we decide whether to run llvm-nm --export-symbols, so we may run it in situations where we wouldn't if the user had used the equivalent -Wl, prefixed options. If we run the export list utility when the user has specified an export list, we could export more symbols than they intended.
2. Add a new functionality to allow redirecting the stdin, stdout, stderr of individual Jobs, if redirects are set for the Job use them, otherwise fall back to the global Compilation redirects if any.
Reviewers: David Tenty, Fangrui Song, Steven Wan
Differential Revision: https://reviews.llvm.org/D119147
To have finer control of IR uwtable attribute generation. For target code generation,
IR nounwind and uwtable may have some interaction. However, for frontend, there are
no semantic interactions so the this new `nouwtable` is marked "SimpleHandler = 1".
Differential Revision: https://reviews.llvm.org/D132592
The method is now wrapped by clang_getUnqualifiedType.
A declaration for clang_getUnqualifiedType was added to
clang-c/Index.h to expose it to user of the library.
An implementation for clang_getUnqualifiedType was introduced in
CXType.cpp that wraps the equivalent method of the underlying
QualType of a CXType.
An export symbol was added to libclang.map under the new version entry
LLVM_16.
A test was added to LibclangTest.cpp that tests the removal of
qualifiers for some CXTypes.
Differential Revision: https://reviews.llvm.org/D132749
Control Flow Guard is only supported on Windows target, therefore there
is no point to make it an accepted attribute for other targets.
Reviewed By: rnk, aaron.ballman
Differential Revision: https://reviews.llvm.org/D132661
In Sema::LookupTemplateName(...) seeks to assert that the ObjectType is complete
or being defined. If the type is incomplete it will attempt to unconditionally
cast it to a TagType and not all incomplete types are a TagType. For example the
type could be void or it could be an IncompleteArray.
This change adds an additional check to confirm it is a TagType before attempting
to check if it is incomplete or being defined
Differential Revision: https://reviews.llvm.org/D132712
Clang crashes when encountering an `if consteval` statement.
This is the minimum fix not to crash.
The fix is consistent with the current behavior of if constexpr,
which does generate coverage data for the discarded branches.
This is of course not correct and a better solution is
needed for both if constexpr and if consteval.
See https://github.com/llvm/llvm-project/issues/54419.
Fixes#57377
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D132723
The patch diagnoses an identifier as a future keyword if it exists in a
future language mode, such as:
int restrict;
in C modes earlier than C99. We now give a warning to the user that
such an identifier is a future keyword. Handles keywords from C as well
as C++.
Differential Revision: https://reviews.llvm.org/D131683
This patch implements P0848 in Clang.
During the instantiation of a C++ class, in `Sema::ActOnFields`, we evaluate constraints for all the SMFs and compare the constraints to compute the eligibility. We defer the computation of the type's [copy-]trivial bits from addedMember to the eligibility computation, like we did for destructors in D126194. `canPassInRegisters` is modified as well to better respect the ineligibility of functions.
Note: Because of the non-implementation of DR1734 and DR1496, I treat deleted member functions as 'eligible' for the purpose of [copy-]triviallity. This is unfortunate, but I couldn't think of a way to make this make sense otherwise.
Reviewed By: #clang-language-wg, cor3ntin, aaron.ballman
Differential Revision: https://reviews.llvm.org/D128619
The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type identifier for each
function and injects verification code before indirect calls.
Unlike the current CFI schemes implemented in LLVM, KCFI does not
require LTO, does not alter function references to point to a jump
table, and never breaks function address equality. KCFI is intended
to be used in low-level code, such as operating system kernels,
where the existing schemes can cause undue complications because
of the aforementioned properties. However, unlike the existing
schemes, KCFI is limited to validating only function pointers and is
not compatible with executable-only memory.
KCFI does not provide runtime support, but always traps when a
type mismatch is encountered. Users of the scheme are expected
to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi`
operand bundle to indirect calls, and LLVM lowers this to a
known architecture-specific sequence of instructions for each
callsite to make runtime patching easier for users who require this
functionality.
A KCFI type identifier is a 32-bit constant produced by taking the
lower half of xxHash64 from a C++ mangled typename. If a program
contains indirect calls to assembly functions, they must be
manually annotated with the expected type identifiers to prevent
errors. To make this easier, Clang generates a weak SHN_ABS
`__kcfi_typeid_<function>` symbol for each address-taken function
declaration, which can be used to annotate functions in assembly
as long as at least one C translation unit linked into the program
takes the function address. For example on AArch64, we might have
the following code:
```
.c:
int f(void);
int (*p)(void) = f;
p();
.s:
.4byte __kcfi_typeid_f
.global f
f:
...
```
Note that X86 uses a different preamble format for compatibility
with Linux kernel tooling. See the comments in
`X86AsmPrinter::emitKCFITypeId` for details.
As users of KCFI may need to locate trap locations for binary
validation and error handling, LLVM can additionally emit the
locations of traps to a `.kcfi_traps` section.
Similarly to other sanitizers, KCFI checking can be disabled for a
function with a `no_sanitize("kcfi")` function attribute.
Relands 67504c9549 with a fix for
32-bit builds.
Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay
Differential Revision: https://reviews.llvm.org/D119296
This patch adds a formatter for `std::coroutine_handle`, both for libc++
and libstdc++. For the type-erased `coroutine_handle<>`, it shows the
`resume` and `destroy` function pointers. For a non-type-erased
`coroutine_handle<promise_type>` it also shows the `promise` value.
With this change, executing the `v t` command on the example from
https://clang.llvm.org/docs/DebuggingCoroutines.html now outputs
```
(task) t = {
handle = coro frame = 0x55555555b2a0 {
resume = 0x0000555555555a10 (a.out`coro_task(int, int) at llvm-example.cpp:36)
destroy = 0x0000555555556090 (a.out`coro_task(int, int) at llvm-example.cpp:36)
}
}
```
instead of just
```
(task) t = {
handle = {
__handle_ = 0x55555555b2a0
}
}
```
Note, how the symbols for the `resume` and `destroy` function pointer
reveal which coroutine is stored inside the `std::coroutine_handle`.
A follow-up commit will use this fact to infer the coroutine's promise
type and the representation of its internal coroutine state based on
the `resume` and `destroy` pointers.
The same formatter is used for both libc++ and libstdc++. It would
also work for MSVC's standard library, however it is not registered
for MSVC, given that lldb does not provide pretty printers for other
MSVC types, either.
The formatter is in a newly added `Coroutines.{h,cpp}` file because there
does not seem to be an already existing place where we could share
formatters across libc++ and libstdc++. Also, I expect this code to grow
as we improve debugging experience for coroutines further.
**Testing**
* Added API test
Differential Revision: https://reviews.llvm.org/D132415
The KCFI sanitizer, enabled with `-fsanitize=kcfi`, implements a
forward-edge control flow integrity scheme for indirect calls. It
uses a !kcfi_type metadata node to attach a type identifier for each
function and injects verification code before indirect calls.
Unlike the current CFI schemes implemented in LLVM, KCFI does not
require LTO, does not alter function references to point to a jump
table, and never breaks function address equality. KCFI is intended
to be used in low-level code, such as operating system kernels,
where the existing schemes can cause undue complications because
of the aforementioned properties. However, unlike the existing
schemes, KCFI is limited to validating only function pointers and is
not compatible with executable-only memory.
KCFI does not provide runtime support, but always traps when a
type mismatch is encountered. Users of the scheme are expected
to handle the trap. With `-fsanitize=kcfi`, Clang emits a `kcfi`
operand bundle to indirect calls, and LLVM lowers this to a
known architecture-specific sequence of instructions for each
callsite to make runtime patching easier for users who require this
functionality.
A KCFI type identifier is a 32-bit constant produced by taking the
lower half of xxHash64 from a C++ mangled typename. If a program
contains indirect calls to assembly functions, they must be
manually annotated with the expected type identifiers to prevent
errors. To make this easier, Clang generates a weak SHN_ABS
`__kcfi_typeid_<function>` symbol for each address-taken function
declaration, which can be used to annotate functions in assembly
as long as at least one C translation unit linked into the program
takes the function address. For example on AArch64, we might have
the following code:
```
.c:
int f(void);
int (*p)(void) = f;
p();
.s:
.4byte __kcfi_typeid_f
.global f
f:
...
```
Note that X86 uses a different preamble format for compatibility
with Linux kernel tooling. See the comments in
`X86AsmPrinter::emitKCFITypeId` for details.
As users of KCFI may need to locate trap locations for binary
validation and error handling, LLVM can additionally emit the
locations of traps to a `.kcfi_traps` section.
Similarly to other sanitizers, KCFI checking can be disabled for a
function with a `no_sanitize("kcfi")` function attribute.
Reviewed By: nickdesaulniers, kees, joaomoreira, MaskRay
Differential Revision: https://reviews.llvm.org/D119296
To support using Control Flow Guard with mingw-w64, Clang needs to
accept `__declspec(guard(nocf))` also for the GNU target. Since mingw
has `#define __declspec(a) __attribute__((a))` as built-in, the simplest
solution is to accept `__attribute__((guard(nocf)))` to be compatible with
MSVC and Clang's msvc target.
As a side effect, this also adds `[[clang::guard(nocf)]]` for C++.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D132302
This patch implements P0848 in Clang.
During the instantiation of a C++ class, in `Sema::ActOnFields`, we evaluate constraints for all the SMFs and compare the constraints to compute the eligibility. We defer the computation of the type's [copy-]trivial bits from addedMember to the eligibility computation, like we did for destructors in D126194. `canPassInRegisters` is modified as well to better respect the ineligibility of functions.
Note: Because of the non-implementation of DR1734 and DR1496, I treat deleted member functions as 'eligible' for the purpose of [copy-]triviallity. This is unfortunate, but I couldn't think of a way to make this make sense otherwise.
Reviewed By: #clang-language-wg, cor3ntin, aaron.ballman
Differential Revision: https://reviews.llvm.org/D128619
This is to clarify that the macro __FLT_EVAL_METHOD__ is not pre-
defined like other preprocessor macros. It will not appear when
preprocessor macros are dumped.
Differential Revision: https://reviews.llvm.org/D124033
Since the patch missed release 15.x and will be included in release 16.x. Also, simplify related tests.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D132414
As proposed in D126215 (ffe7950ebc),
I'm dropping the `-analyzer-store` and
`-analyzer-opt-analyze-nested-blocks` clang frontend flags.
I'm also dropping the corresponding commandline handlers of `scanbuild`.
This behavior is planned to be part of `clang-16`.
Reviewed By: xazax.hun
Differential Revision: https://reviews.llvm.org/D132289
We use the `clang-offload-packager` too bundle many files into a single
binary format containing metadata. This is used for offloading
compilation which may contain multiple device binaries of different
types and architectures in a single file. We use this special binary
format to store these files along with some necessary metadata around
them. We use this format because of the difficulty of determining the
filesize of the various binary inputs that will be passed to the
offloading toolchain rather than engineering a solution for each input.
Previously we only support packaing many files into a single binary.
This patch adds support for doing the reverse by using the same
`--image=` syntax. To unpackage a binary we now present an input file
instead of an output.
Reviewed By: tra
Differential Revision: https://reviews.llvm.org/D129507
Previously when I wrote this document, I felt the completed scripts was
lengthy, redundant and not easy to read. So I didn't add complete
examples in the previous commit.
However, in the recent discussion with @avogelsgesang, I found people
may not know how to use debugging scripts to improve their debugging
efficiency. So now, I feel like it is helpful to put the examples even
if they are a little bit long.
Test Plan: make docs-clang-html
Reviewed By: avogelsgesang
Differential Revision: https://reviews.llvm.org/D132451
This reverts commit d483730d8c.
This allegedly breaks a significant part of facebooks internal build.
Reverting while we wait for them to provide a reproducer of this from
@wlei.
The patch mainly focuses on the no warnings for -Wtautological-compare.
It work fine for the positive numbers but doesn't for the negative
numbers. This is because the warning explicitly checks for an
IntegerLiteral AST node, but -1 is represented by a UnaryOperator with
an IntegerLiteral sub-Expr.
Fixes#42918
Differential Revision: https://reviews.llvm.org/D130510
Fix for the problem with displaying options `-fsyntax-only` in clang and flang-new in help
Fix https://github.com/llvm/llvm-project/issues/57033
Before:
``` $ clang -help | grep syntax
-objcmt-migrate-property-dot-syntax
Enable migration of setter/getter messages to property-dot syntax
```
After:
```
$ clang -help | grep syntax
-fsyntax-only Run the preprocessor, parser and semantic analysis stages
-objcmt-migrate-property-dot-syntax
Enable migration of setter/getter messages to property-dot syntax
```
Reviewed By: vzakhari, awarzynski, MaskRay, alexiprof
Differential Revision: https://reviews.llvm.org/D131808
Instead of complaining about default initialization, tell users that
constexpr variables need to be initialized by a constant expression.
Differential Revision: https://reviews.llvm.org/D131662
The previous implementation translated from names like sifive-7-series
to sifive-7-rv32 or sifive-7-rv64. This also required sifive-7-rv32
and sifive-7-rv64 to be valid CPU names. As those are not real
CPUs it doesn't make sense to accept them in -mcpu.
This patch does away with the translation and adds sifive-7-series
directly to RISCV.td. Removing sifive-7-rv32 and sifive-7-rv64.
sifive-7-series is only allowed in -mtune.
I've also added "rocket" to RISCV.td but have not removed rocket-rv32
or rocket-rv64.
To prevent -mcpu=sifive-7-series or -mcpu=rocket being used with llc,
I've added a Feature32Bit to all rv32 CPUs. And made it an error to
have an rv32 triple without Feature32Bit. sifive-7-series and rocket
do not have Feature32Bit or Feature64Bit set so the user would need
to provide -mattr=+32bit or -mattr=+64bit along with the -mcpu to
avoid the error.
SiFive no longer names their newer products with 3, 5, or 7 series.
Instead we have p200 series, x200 series, p500 series, and p600 series.
Following the previous behavior would require a sifive-p500-rv32 and
sifive-p500-rv64 in order to support -mtune=sifive-p500-series. There
is currently no p500 product, but it could start getting confusing if
there was in the future.
I'm open to hearing alternatives for how to achieve my main goal
of removing sifive-7-rv32/rv64 as a CPU name.
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D131708
Add the clang option -finline-max-stacksize=<N> to suppress inlining
of functions whose stack size exceeds the given value.
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D131986
We deferred the evaluation of dependent immediate invocations in https://reviews.llvm.org/D119375 until instantiation.
We should also not consider them referenced from a non-consteval context.
Fixes: https://github.com/llvm/llvm-project/issues/55601
```
template<typename T>
class Bar {
consteval static T x() { return 5; }
public:
Bar() : a(x()) {}
private:
int a;
};
Bar<int> g();
```
Is now accepted by clang. Previously it errored with: `cannot take address of consteval function 'x' outside of an immediate invocation Bar() : a(x()) {}`
Differential Revision: https://reviews.llvm.org/D132031
This reverts commit 258c3aee54.
This should fix the libc++ issue that caused the revert, by re-designing
slightly how we determined when we should evaluate the constraints.
Additionally, many of the other components to the original patch (the
NFC parts) were committed separately to shrink the size of this patch
for review.
Differential Revision: https://reviews.llvm.org/D126907
When expanding undeclared function parameters, we should initialize
the original number of expansions, if known, before trying to expand
them, otherwise a length mismatch with an outer pack might not be
diagnosed.
Fixes PR56094.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D131802
DR692 handles two cases: pack expansion (for class/var template) and function parameter pack. The former needs DR1432 as a fix, and the latter needs DR1395 as a fix. However, DR1432 has not yet made a wording change. so I made a tentative fix for DR1432 with the same spirit as DR1395.
Reviewed By: aaron.ballman, erichkeane, #clang-language-wg
Differential Revision: https://reviews.llvm.org/D128745
Found during clang 15 RC1 testing due to the new diagnostic added by @royjacobson since clang 14. Uncertain if this fix meets the bar to also be applied to the release branch.
If accepted, I'll need someone with commit access to submit on my behalf.
Reviewed By: royjacobson, aaron.ballman, erichkeane
Differential Revision: https://reviews.llvm.org/D131730
Before this patch type traits are checked in Parser, so use type traits
directly did not cause assertion faults. However if type traits are initialized
from a template, we didn't perform arity checks before evaluating. This
patch moves arity checks from Parser to Sema, and performing arity
checks in Sema actions, so type traits get checked corretly.
Crash input:
```
template<class... Ts> bool b = __is_constructible(Ts...);
bool x = b<>;
```
After this patch:
```
clang/test/SemaCXX/type-trait-eval-crash-issue-57008.cpp:5:32: error: type trait requires 1 or more arguments; have 0 arguments
template<class... Ts> bool b = __is_constructible(Ts...);
^~~~~~~~~~~~~~~~~~
clang/test/SemaCXX/type-trait-eval-crash-issue-57008.cpp:6:10: note: in instantiation of variable template specialization 'b<>' requested here
bool x = b<>;
^
1 error generated.
```
See https://godbolt.org/z/q39W78hsK.
Fixes https://github.com/llvm/llvm-project/issues/57008
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D131423
Followup patch for D128083
Previously, using a non-consteval constructor from an consteval constructor would code generates the consteval constructor.
Example
```
template <typename T>
struct S {
T i;
consteval S() = default;
};
struct Foo {
Foo() {}
};
void func() {
S<Foo> three; // incorrectly accepted by clang.
}
```
This happened because clang erroneously disregards `consteval` specifier for a `consteval explicitly defaulted special member functions in a class template` if it has dependent data members without a `consteval default constructor`.
According to
```
C++14 [dcl.constexpr]p6 (CWG DR647/CWG DR1358):
If the instantiated template specialization of a constexpr function
template or member function of a class template would fail to satisfy
the requirements for a constexpr function or constexpr constructor, that
specialization is still a constexpr function or constexpr constructor,
even though a call to such a function cannot appear in a constant
expression.
```
Therefore the `consteval defaulted constructor of a class template` should be considered `consteval` even if the data members' default constructors are not consteval.
Keeping this constructor `consteval` allows complaining while processing the call to data member constructors.
(Same applies for other special member functions).
This works fine even when we have more than one default constructors since we process the constructors after the templates are instantiated.
This does not address initialization issues raised in
[2602](https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#2602) and compiler divergence seen in https://godbolt.org/z/va9EMvvMe
Fixes: https://github.com/llvm/llvm-project/issues/51593
Differential Revision: https://reviews.llvm.org/D131479
Clang currently crashes when lowering a consteval list initialization
of a temporary. This is partially working around an issue in the
template instantiation code (TreeTransform::TransformCXXTemporaryObjectExpr())
that does not yet know how to handle list initialization of temporaries
in all cases. However, it's also helping reduce fragility by ensuring
we always have a valid QualType when trying to emit a constant
expression during IR generation.
Fixes#55871
Differential Revision: https://reviews.llvm.org/D131194
Previously the table in LanguageExtensions said that sizeof worked on
SVE types but this is only correct for fixed-length vectors so a
clarification has been added.
For failed static assertions, try to take the expression apart and print
useful information about why it failed. In particular, look at binary
operators and print the compile-time evaluated value of the LHS/RHS.
Differential Revision: https://reviews.llvm.org/D130894
When clang includes a PCH, it tolerates some amount of differences
between the defines used when creating and when including the PCH
- this seems to be intentionally allowed in
c379c07240 (and later extended in
b636875196).
When using a PCH (or when picking a PCH out of a directory containing
multiple candidates) Clang used to accept the header if there were
defines on the command line when creating the PCH that are missing
when using the PCH, or vice versa, defines only set when using the
PCH.
The only cases where Clang explicitly rejected the use of a PCH
is if there was an explicit conflict between the options, e.g.
-DFOO=1 vs -DFOO=2, or -DFOO vs -UFOO.
The latter commit added a FIXME that we really should check whether
mismatched defines actually were used somewhere in the PCH, so that
the define would affect the outcome. This FIXME has stood unaddressed
since 2012.
This differs from GCC, which rejects PCH files if the defines differ
at all.
When explicitly including a single PCH file, the relaxed policy
of allowing minor differences is harmless for correct use cases
(but may fail to diagnose mismtaches), and potentially allow using
PCHs in wider cases (where the user intentionally know that the
differences in defines are harmless for the PCH).
However, for GCC style PCH directories, with a directory containing
multiple PCH variants and the compiler should pick the correct match
out of them, Clang's relaxed logic was problematic. The directory
could contain two otherwise identical PCHs, but one built with -DFOO
and one without. When attempting to include a PCH and iterating over
the candidates in the directory, Clang would essentially pick the
first one out of the two, even if there existed a better, exact
match in the directory.
Keep the relaxed checking when specificlly including one named
PCH file, but require strict matches when trying to pick the right
candidate out of a GCC style directory with alternatives.
This fixes https://github.com/lhmouse/mcfgthread/issues/63.
Differential Revision: https://reviews.llvm.org/D126676
Implicitly converting between incompatible function pointers in C is
currently a default-on warning (it is an error in C++). However, this
is very poor security posture. A mismatch in parameters or return
types, or a mismatch in calling conventions, etc can lead to
exploitable security vulnerabilities. Rather than allow this unsafe
practice with a warning, this patch strengthens the warning to be an
error (while still allowing users the ability to disable the error or
the warning entirely to ease migration). Users should either ensure the
signatures are correctly compatible or they should use an explicit cast
if they believe that's more reasonable.
Differential Revision: https://reviews.llvm.org/D131351
Previously the language extension documentation didn't mention SVE and
was incomplete in listing the C/C++ operators supported on NEON. This
corrects the documentation to be in line with the implementation.
A one-bit signed bit-field can only hold the values 0 and -1; this
corrects the diagnostic behavior accordingly.
Fixes#53253
Differential Revision: https://reviews.llvm.org/D131255
In D130058 we diagnose the undefined behavior of setting the value outside the
range of the enumerations values for an enum without a fixed underlying type.
Based on feedback we will provide users to the ability to downgrade this
diagnostic to a waring to allow for a transition period. We expect to turn this
diagnostic to an error in the next release.
Differential Revision: https://reviews.llvm.org/D131307
The header from 62e0681afb does something with
LLVM_FALLTHROUGH. Now that llvm-project has switched to C++17 and
LLVM_FALLTHROUGH uses have been migrated to [[fallthrough]], the header is
unneeded.
Reviewed By: JDevlieghere
Differential Revision: https://reviews.llvm.org/D131422
Along with the new documentation this also re-organizes the HLSL docs
to a subdirectory. The hope is to continue to expand this documentation
as the HLSL implementation advances.
Differential Revision: https://reviews.llvm.org/D130794
Support for functions wmempcpy, wmemmove, wmemcmp is added to the checker.
The same tests are copied that exist for the non-wide versions, with
non-wide functions and character types changed to the wide version.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D130470
Consider:
A == 5 && A != 5
IfA is 5, the old collectConjunctionTerms() would call itself again for
the LHS (which it ignores), then the RHS (which it also ignores) and
then just return without ever adding anything to the Terms array.
Differential Revision: https://reviews.llvm.org/D131070
In D130807 we added the `skipprofile` attribute. This commit
changes the format so we can either `forbid` or `skip` profiling
functions by adding the `noprofile` or `skipprofile` attributes,
respectively. The behavior of the original format remains
unchanged.
Also, add the `skipprofile` attribute when using
`-fprofile-function-groups`.
This was originally landed as https://reviews.llvm.org/D130808 but was
reverted due to a Windows test failure.
Differential Revision: https://reviews.llvm.org/D131195
We would like to make the ACLE NEON and SVE intrinsics more useable by
gating them on the target, not by ifdef preprocessor macros. In order to
do this the types they use need to be available. This patches makes
__bf16 always available under AArch64 not just when the bf16
architecture feature is present. This bringing it in-line with GCC. In
subsequent patches the NEON bfloat16x8_t and SVE svbfloat16_t types
(along with bfloat16_t used in arm_sve.h) will be made unconditional
too.
The operations valid on the types are still very limited. They can be
used as a storage type, but the intrinsics used for convertions are
still behind an ifdef guard in arm_neon.h/arm_bf16.h.
Differential Revision: https://reviews.llvm.org/D130973
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
In D130807 we added the `skipprofile` attribute. This commit
changes the format so we can either `forbid` or `skip` profiling
functions by adding the `noprofile` or `skipprofile` attributes,
respectively. The behavior of the original format remains
unchanged.
Also, add the `skipprofile` attribute when using
`-fprofile-function-groups`.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D130808
This patch enhances clang's ability to check compile-time determinable
string literals as format strings, and can give FixIt hints at literals
(unlike gcc). Issue https://github.com/llvm/llvm-project/issues/55805
mentiond two compile-time string cases. And this patch partially fixes
one.
```
constexpr const char* foo() {
return "%s %d";
}
int main() {
printf(foo(), "abc", "def");
return 0;
}
```
This patch enables clang check format string for this:
```
<source>:4:24: warning: format specifies type 'int' but the argument has type 'const char *' [-Wformat]
printf(foo(), "abc", "def");
~~~~~ ^~~~~
<source>:2:42: note: format string is defined here
constexpr const char *foo() { return "%s %d"; }
^~
%s
1 warning generated.
```
Reviewed By: aaron.ballman
Signed-off-by: YingChi Long <me@inclyc.cn>
Differential Revision: https://reviews.llvm.org/D130906
This completes the implementation of P1091R3 and P1381R1.
This patch allow the capture of structured bindings
both for C++20+ and C++17, with extension/compat warning.
In addition, capturing an anonymous union member,
a bitfield, or a structured binding thereof now has a
better diagnostic.
We only support structured bindings - as opposed to other kinds
of structured statements/blocks. We still emit an error for those.
In addition, support for structured bindings capture is entirely disabled in
OpenMP mode as this needs more investigation - a specific diagnostic indicate the feature is not yet supported there.
Note that the rest of P1091R3 (static/thread_local structured bindings) was already implemented.
at the request of @shafik, i can confirm the correct behavior of lldb wit this change.
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/52720
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D122768
We already correctly rejected:
typedef __attribute__((vector_size(16))) _BitInt(4) Ty;
but we would assert with:
typedef __attribute__((ext_vector_type(4))) _BitInt(4) Ty;
Now we issue the same error in both cases.
This completes the implementation of P1091R3 and P1381R1.
This patch allow the capture of structured bindings
both for C++20+ and C++17, with extension/compat warning.
In addition, capturing an anonymous union member,
a bitfield, or a structured binding thereof now has a
better diagnostic.
We only support structured bindings - as opposed to other kinds
of structured statements/blocks. We still emit an error for those.
In addition, support for structured bindings capture is entirely disabled in
OpenMP mode as this needs more investigation - a specific diagnostic indicate the feature is not yet supported there.
Note that the rest of P1091R3 (static/thread_local structured bindings) was already implemented.
at the request of @shafik, i can confirm the correct behavior of lldb wit this change.
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/54300
Fixes https://github.com/llvm/llvm-project/issues/52720
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D122768
VisitCXXConstructExpr() will later do something similar, but for large
arrays, we should try to do it once an not for every element.
Fixes#56774
Differential Revision: https://reviews.llvm.org/D130791
We didn't check that a destructor's name matches the directly enclosing class if the class was dependent.
I enabled the check we already had for non-dependent types, which seems to work. Added appropriate tests.
Fixes GitHub issue #56772
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D130936
This reverts commit 0cc3c184c7.
The changes did not account for templated code where one instantiation
may trigger the diagnostic but other instantiations will not, as in:
```
template <int I, class T>
void foo(int x) {
bool b1 = (x & sizeof(T)) == 8;
bool b2 = (x & I) == 8;
bool b3 = (x & 4) == 8;
}
void run(int x) {
foo<4, int>(8);
}
```
I went over the output of the following mess of a command:
(ulimit -m 2000000; ulimit -v 2000000; git ls-files -z |
parallel --xargs -0 cat | aspell list --mode=none --ignore-case |
grep -E '^[A-Za-z][a-z]*$' | sort | uniq -c | sort -n |
grep -vE '.{25}' | aspell pipe -W3 | grep : | cut -d' ' -f2 | less)
and proceeded to spend a few days looking at it to find probable typos
and fixed a few hundred of them in all of the llvm project (note, the
ones I found are not anywhere near all of them, but it seems like a
good start).
Differential Revision: https://reviews.llvm.org/D130827
This is a follow-up to D130058 to fix how we handle the Max value we obtain from
getValueRange(...) in IntExprEvaluator::VisitCastExpr(...) which in the case of
an enum that contains an enumerator with the max integer value will overflow by
one.
The fix is to decrement the value of Max and use slt and ult for comparison Vs
sle and ule.`
Differential Revision: https://reviews.llvm.org/D130811
C99 6.7.4p2 clarifies that a function specifier can only be used in the
declaration of a function. _Noreturn is a function specifier, so it is
a constraint violation to write it on a structure or union field, but
we missed that case.
Fixes#56800
DR2338 clarified that it was undefined behavior to set the value outside the
range of the enumerations values for an enum without a fixed underlying type.
We should diagnose this with a constant expression context.
Differential Revision: https://reviews.llvm.org/D130058
The patch mainly focuses on the lack of warnings for
-Wtautological-compare. It works fine for positive numbers but doesn't
for negative numbers. This is because the warning explicitly checks for
an IntegerLiteral AST node, but -1 is represented by a UnaryOperator
with an IntegerLiteral sub-Expr.
For the below code we have warnings:
if (0 == (5 | x)) {}
but not for
if (0 == (-5 | x)) {}
This patch changes the analysis to not look at the AST node directly to
see if it is an IntegerLiteral, but instead attempts to evaluate the
expression to see if it is an integer constant expression. This handles
unary negation signs, but also handles all the other possible operators
as well.
Fixes#42918
Differential Revision: https://reviews.llvm.org/D130510
DR2338 clarified that it was undefined behavior to set the value outside the
range of the enumerations values for an enum without a fixed underlying type.
We should diagnose this with a constant expression context.
Differential Revision: https://reviews.llvm.org/D130058
Add the support for `atomic compare` and `atomic compare capture` in the
release note of clang.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D129211
Without the "found declaration" it is later not possible to know where the operator declaration
was brought into the scope calling it.
The initial motivation for this fix came from #55095. However, this also has an influence on
`clang -ast-dump` which now prints a `UsingShadow` attribute for operators only visible through
`using` statements. Also, clangd now correctly references the `using` statement instead of the
operator directly.
Reviewed By: shafik
Differential Revision: https://reviews.llvm.org/D129973
Currently, the use of preferred_name would block implementing std
modules in libcxx. See https://github.com/llvm/llvm-project/issues/56490
for example.
The problem is pretty hard and it looks like we couldn't solve it in a
short time. So we sent this patch as a workaround to avoid blocking us
to modularize STL. This is intended to be fixed properly in the future.
Reviewed By: erichkeane, aaron.ballman, tahonermann
Differential Revision: https://reviews.llvm.org/D130331
Before the patch we calculated the NRVO candidate looking at the
variable's whole enclosing scope. The research in [P2025] shows that
looking at the variable's potential scope is better and covers more
cases where NRVO would be safe and desirable.
Many thanks to @Izaron for the original implementation.
Reviewed By: ChuanqiXu
Differential Revision: https://reviews.llvm.org/D119792
Since clang15 is going to be branched in July 26, and C++ modules still
lack an update on ReleaseNotes. Although it is not complete yet, I think
it would be better to add one since we've done many works for C++20
Modules in clang15.
Differential Revision: https://reviews.llvm.org/D129138
This partially reverts c7b3a91017. Having
libclang.so with a different SONAME than the other LLVM libraries was
causing a lot of confusion for users. Also, this change did not really
acheive it's purpose of allowing apps to use newer versions of
libclang.so without rebuilding, because a new version of libclang.so
requires a new version of libLLVM.so, which does not have a stable ABI.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D129160
Currently in Sema::ActOnEnumBody(...) when calculating NumPositiveBits we miss
the case where there is only a single enumerator with value zero and the case of
an empty enum. In both cases we end up with zero positive bits when in fact we
need one bit to store the value zero.
This PR updates the calculation to account for these cases.
Differential Revision: https://reviews.llvm.org/D130301
and use fallback only for C.
It fixes the isssue with clang-cl:
```
#include <stdatomic.h>
#include <stdbool.h>
#ifdef __cplusplus
#include <atomic>
using namespace std;
#endif
int main() {
atomic_bool b = true;
}
```
```
$ clang-cl /TC main.cpp
# works
```
```
$ clang-cl /TP /std:c++20 main.cpp
stdatomic.h(70,6): error: conflicting types for 'atomic_thread_fence'
void atomic_thread_fence(memory_order);
^
atomic(166,24): note: previous definition is here
extern "C" inline void atomic_thread_fence(const memory_order _Order) noexcept {
...
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.
```
Many errors but
`<stdatomic.h>` has many macros to built-in functions.
```
#define atomic_thread_fence(order) __c11_atomic_thread_fence(order)
```
and MSVC `<atomic>` has real functions.
and the built-in functions are redefined.
Reviewed By: #libc, aaron.ballman, Mordante
Differential Revision: https://reviews.llvm.org/D130419
Support for functions wmemcpy, wcslen, wcsnlen is added to the checker.
Documentation and tests are updated and extended with the new functions.
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D130091
As per P2327R1,
|=, &= and ^= are no longer deprecated in all languages mode.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D130421
The #warning directive is standard in C++2b and C2x,
this adjusts the pedantic and extensions warning accordingly.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D130415
This implements
N2836 Identifier Syntax using Unicode Standard Annex 31.
The feature was already implemented for C++,
and the semantics are the same.
Unlike C++ there was, afaict, no decision to
backport the feature in older languages mode,
so C17 and earlier are not modified and the
code point tables for these language modes are conserved.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D130416
Clang has traditionally allowed C programs to implicitly convert
integers to pointers and pointers to integers, despite it not being
valid to do so except under special circumstances (like converting the
integer 0, which is the null pointer constant, to a pointer). In C89,
this would result in undefined behavior per 3.3.4, and in C99 this rule
was strengthened to be a constraint violation instead. Constraint
violations are most often handled as an error.
This patch changes the warning to default to an error in all C modes
(it is already an error in C++). This gives us better security posture
by calling out potential programmer mistakes in code but still allows
users who need this behavior to use -Wno-error=int-conversion to retain
the warning behavior, or -Wno-int-conversion to silence the diagnostic
entirely.
Differential Revision: https://reviews.llvm.org/D129881
This patch moves `Analysis/FlowSensitive/NoopAnalysis.h` from `clang/unittests/` to `clang/include/clang/`, so that we can use it for doing context-sensitive analysis.
Reviewed By: ymandel, gribozavr2, sgatev
Differential Revision: https://reviews.llvm.org/D130304
message expressions
For an Obj-C message expression `[o m]`, the adding matcher will match
the declaration of the method `m`. This commit overloads the existing
`callee` ASTMatcher, which originally was only for C/C++ nodes but
also applies to Obj-C messages now.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D129398
EnumDecl's promotion type is set either to the parsed type or calculated type
after completing its definition. When it's bool type and has no definition,
its promotion type is bool which is not allowed by clang.
Fixes#56560.
Differential Revision: https://reviews.llvm.org/D130210
Based on the discussion at [1], this patch adds a Clang flag called
-fexperimental-library that controls whether experimental library
features are provided in libc++. In essence, it links against the
experimental static archive provided by libc++ and defines a feature
that can be picked up by libc++ to enable experimental features.
This ensures that users don't start depending on experimental
(and hence unstable) features unknowingly.
[1]: https://discourse.llvm.org/t/rfc-a-compiler-flag-to-enable-experimental-unstable-language-and-library-features
Differential Revision: https://reviews.llvm.org/D121141
Some code [0] consider that trailing arrays are flexible, whatever their size.
Support for these legacy code has been introduced in
f8f6324983 but it prevents evaluation of
__builtin_object_size and __builtin_dynamic_object_size in some legit cases.
Introduce -fstrict-flex-arrays=<n> to have stricter conformance when it is
desirable.
n = 0: current behavior, any trailing array member is a flexible array. The default.
n = 1: any trailing array member of undefined, 0 or 1 size is a flexible array member
n = 2: any trailing array member of undefined or 0 size is a flexible array member
This takes into account two specificities of clang: array bounds as macro id
disqualify FAM, as well as non standard layout.
Similar patch for gcc discuss here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836
[0] https://docs.freebsd.org/en/books/developers-handbook/sockets/#sockets-essential-functions
When an issue exists in the main file (caller) instead of an included file
(callee), using a `src` pattern applying to the included file may be
inappropriate if it's the caller's responsibility. Add `mainfile` prefix to check
the main filename.
For the example below, the issue may reside in a.c (foo should not be called
with a misaligned pointer or foo should switch to an unaligned load), but with
`src` we can only apply to the innocent callee a.h. With this patch we can use
the more appropriate `mainfile:a.c`.
```
//--- a.h
// internal linkage
static inline int load(int *x) { return *x; }
//--- a.c, -fsanitize=alignment
#include "a.h"
int foo(void *x) { return load(x); }
```
See the updated clang/docs/SanitizerSpecialCaseList.rst for a caveat due
to C++ vague linkage functions.
Reviewed By: #sanitizers, kstoimenov, vitalybuka
Differential Revision: https://reviews.llvm.org/D129832
Summary: Introduce a new function 'clang_analyzer_value'. It emits a report that in turn prints a RangeSet or APSInt associated with SVal. If there is no associated value, prints "n/a".
AcceptedPublic
Currently CXXMethodDecl::isMoveAssignmentOperator() does not look though type
sugar and so if the parameter is a type alias it will not be able to detect
that the method is a move assignment operator. This PR fixes that and adds a set
of tests that covers that we correctly detect special member functions when
defaulting or deleting them.
This fixes: https://github.com/llvm/llvm-project/issues/56456
Differential Revision: https://reviews.llvm.org/D129591
Add two options, `-fprofile-function-groups=N` and `-fprofile-selected-function-group=i` used to partition functions into `N` groups and only instrument the functions in group `i`. Similar options were added to xray in https://reviews.llvm.org/D87953 and the goal is the same; to reduce instrumented size overhead by spreading the overhead across multiple builds. Raw profiles from different groups can be added like normal using the `llvm-profdata merge` command.
Reviewed By: ianlevesque
Differential Revision: https://reviews.llvm.org/D129594
WG21 approved delimited escape sequences and named escape
sequences.
Adjust the extension warnings accordingly, and update
the release notes.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D129664
clang-format's documentation documented the more general clang-format-diff.py
script. Add documentation for the less general but arguably easier-to-use
git integration as well.
Differential Revision: https://reviews.llvm.org/D129563
CStringChecker is using getByteLength to get the length of a string
literal. For targets where a "char" is 8-bits, getByteLength() and
getLength() will be equal for a C string, but for targets where a "char"
is 16-bits getByteLength() returns the size in octets.
This is verified in our downstream target, but we have no way to add a
test case for this case since there is no target supporting 16-bit
"char" upstream. Since this cannot have a test case, I'm asserted this
change is "correct by construction", and visually inspected to be
correct by way of the following example where this was found.
The case that shows this fails using a target with 16-bit chars is here.
getByteLength() for the string literal returns 4, which fails when
checked against "char x[4]". With the change, the string literal is
evaluated to a size of 2 which is a correct number of "char"'s for a
16-bit target.
```
void strcpy_no_overflow_2(char *y) {
char x[4];
strcpy(x, "12"); // with getByteLength(), returns 4 using 16-bit chars
}
```
This change exposed that embedded nulls within the string are not
handled. This is documented as a FIXME for a future fix.
```
void strcpy_no_overflow_3(char *y) {
char x[3];
strcpy(x, "12\0");
}
```
Reviewed By: martong
Differential Revision: https://reviews.llvm.org/D129269
Introduce an off-by default `-Winvalid-utf8` warning
that detects invalid UTF-8 code units sequences in comments.
Invalid UTF-8 in other places is already diagnosed,
as that cannot appear in identifiers and other grammar constructs.
The warning is off by default as its likely to be somewhat disruptive
otherwise.
This warning allows clang to conform to the yet-to be approved WG21
"P2295R5 Support for UTF-8 as a portable source file encoding"
paper.
Reviewed By: aaron.ballman, #clang-language-wg
Differential Revision: https://reviews.llvm.org/D128059
This reverts commit cc309721d2 because it
breaks the following tests on GreenDragon:
TestDataFormatterObjCCF.py
TestDataFormatterObjCExpr.py
TestDataFormatterObjCKVO.py
TestDataFormatterObjCNSBundle.py
TestDataFormatterObjCNSData.py
TestDataFormatterObjCNSError.py
TestDataFormatterObjCNSNumber.py
TestDataFormatterObjCNSURL.py
TestDataFormatterObjCPlain.py
TestDataFormatterObjNSException.py
https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/45288/
Between issues such as
https://github.com/llvm/llvm-project/issues/56323, the fact that this
lowering (unlike the code in amdgpu-to-rocdl) does not correctly set
up bounds checks (and thus will cause page faults on reads that might
need to be padded instead), and that fixing these problems would,
essentially, involve replicating amdgpu-to-rocdl, remove
--vector-to-rocdl for being broken. In addition, the lowering does not
support many aspects of transfer_{read,write}, like supervectors, and
may not work correctly in their presence.
We (the MLIR-based convolution generator at AMD) do not use this
conversion pass, nor are we aware of any other clients.
Migration strategies:
- Use VectorToLLVM
- If buffer ops are particularly needed in your application, use
amdgpu.raw_buffer_{load,store}
A VectorToAMDGPU pass may be introduced in the future.
Reviewed By: ThomasRaoux
Differential Revision: https://reviews.llvm.org/D129308
Introduce an off-by default `-Winvalid-utf8` warning
that detects invalid UTF-8 code units sequences in comments.
Invalid UTF-8 in other places is already diagnosed,
as that cannot appear in identifiers and other grammar constructs.
The warning is off by default as its likely to be somewhat disruptive
otherwise.
This warning allows clang to conform to the yet-to be approved WG21
"P2295R5 Support for UTF-8 as a portable source file encoding"
paper.
Reviewed By: aaron.ballman, #clang-language-wg
Differential Revision: https://reviews.llvm.org/D128059
C++20 deprecated ATOMIC_FLAG_INIT thinking it was deprecated in C when it
wasn't. It is expected to be undeprecated in C++23 as part of LWG3659
(https://wg21.link/LWG3659), which is currently Tentatively Ready.
This handles the case where the user includes <stdatomic.h> in C++ code in a
freestanding compile mode. The corollary libc++ changes are in
1544d1f9fd.
Otherwise these functions are not instantiated and we end up with an undefined
symbol.
Fix#55560
Differential Revision: https://reviews.llvm.org/D128119
Introduce an off-by default `-Winvalid-utf8` warning
that detects invalid UTF-8 code units sequences in comments.
Invalid UTF-8 in other places is already diagnosed,
as that cannot appear in identifiers and other grammar constructs.
The warning is off by default as its likely to be somewhat disruptive
otherwise.
This warning allows clang to conform to the yet-to be approved WG21
"P2295R5 Support for UTF-8 as a portable source file encoding"
paper.
Reviewed By: aaron.ballman, #clang-language-wg
Differential Revision: https://reviews.llvm.org/D128059
Add a fix-it for the common case of setters/constructors using parameters with the same name as fields
```lang=c++
struct A{
int X;
A(int X) { /*this->*/X = X; }
void setX(int X) { /*this->*/X = X;
};
```
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D129202
Update the references to the old Mailman mailing lists to point to Discourse forums.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D128766
Previously in D99179, I tried to construct debug information for
coroutine frames in the middle end to enhance the debugability for
coroutines. But I forget to add ReleaseNotes to hint people and
documents to help people to use. My bad. @probinson revealed this in
https://github.com/llvm/llvm-project/issues/55916.
So I try to add the use document now.
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D127626
D127209 fixed LLVM to bring it in line with the AAPCS. The fix affects
functions where the first SVE parameter appears in the 9th or later
arguments, and the function does not return an SVE type.
Differential Revision: https://reviews.llvm.org/D129135
This reverts commit 4174f0ca61.
Also revert follow-up "[Clang] Fix invalid utf-8 detection"
This reverts commit bf45e27a67.
The second commit broke tests, see comments on
https://reviews.llvm.org/D129223, and it sounds like the first
commit isn't valid without the second one. So reverting both for now.
Aaron Ballman