This reverts commit 4cf98f973a13c5049322abff43f0dff3c214311b.
The test fails on mac bots, see comments on https://reviews.llvm.org/D122820
Also reverts follow-ups eb920989865d992093993143ba3c6e71126cbb89 and
861c189d2a5203ba8c8e983e8d2e109c0de153a5.
We expect that `extern "C"` static functions to be usable in things like
inline assembly, as well as ifuncs:
See the bug report here: https://github.com/llvm/llvm-project/issues/54549
However, we were diagnosing this as 'not defined', because the
ifunc's attempt to look up its resolver would generate a declared IR
function.
Additionally, as background, the way we allow these static extern "C"
functions to work in inline assembly is by making an alias with the C
mangling in MOST situations to the version we emit with
internal-linkage/mangling.
The problem here was multi-fold: First- We generated the alias after the
ifunc was checked, so the function by that name didn't exist yet.
Second, the ifunc's generation caused a symbol to exist under the name
of the alias already (the declared function above), which suppressed the
alias generation.
This patch fixes all of this by moving the checking of ifuncs/CFE aliases
until AFTER we have generated the extern-C alias. Then, it does a
'fixup' around the GlobalIFunc to make sure we correct the reference.
Differential Revision: https://reviews.llvm.org/D122608
As reported in https://github.com/llvm/llvm-project/issues/54588
and discussed in https://github.com/itanium-cxx-abi/cxx-abi/issues/139
We are supposed to do a DFS, pre-order, decl-order search for a name for
the union in this case. Prevoiusly we crashed because the IdentiferInfo
pointer was nullptr, so this makes sure we have a name in the cases
described by the ABI.
I added an llvm-unreachable to cover an unexpected case at the end of
the new function with information/reference to the ABI in case we come
up with some way to get back to here.
Differential Revision: https://reviews.llvm.org/D122820
Implement a demangleable strong ownership symbol mangling.
* The original module symbol mangling scheme turned out to be
undemangleable.
* The hoped-for C++17 compatibility of weak ownership turns out to be
fragile
* C++20 now has better ways of controlling C++17 compatibility
The issue is captured on the ABI list at:
https://github.com/itanium-cxx-abi/cxx-abi/issues/134
GCC implements this new mangling.
The old mangling is unceremoniously dropped. No backwards
compatibility, no deprectated old-mangling flag. It was always
labelled experimental. (Old and new manglings cannot be confused.)
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D122256
Also, check that NRVO currently isn't performed in test25. The checks
were accidentally removed when https://reviews.llvm.org/D122425 disabled
inlining.
This builtin returns the address of a global instance of the
`std::source_location::__impl` type, which must be defined (with an
appropriate shape) before calling the builtin.
It will be used to implement std::source_location in libc++ in a
future change. The builtin is compatible with GCC's implementation,
and libstdc++'s usage. An intentional divergence is that GCC declares
the builtin's return type to be `const void*` (for
ease-of-implementation reasons), while Clang uses the actual type,
`const std::source_location::__impl*`.
In order to support this new functionality, I've also added a new
'UnnamedGlobalConstantDecl'. This artificial Decl is modeled after
MSGuidDecl, and is used to represent a generic concept of an lvalue
constant with global scope, deduplicated by its value. It's possible
that MSGuidDecl itself, or some of the other similar sorts of things
in Clang might be able to be refactored onto this more-generic
concept, but there's enough special-case weirdness in MSGuidDecl that
I gave up attempting to share code there, at least for now.
Finally, for compatibility with libstdc++'s <source_location> header,
I've added a second exception to the "cannot cast from void* to T* in
constant evaluation" rule. This seems a bit distasteful, but feels
like the best available option.
Reviewers: aaron.ballman, erichkeane
Differential Revision: https://reviews.llvm.org/D120159
Previously, we would instantiate the UDL by marking the function as
referenced and potentially binding to a temporary; this skipped
transforming the call when the UDL was dependent on a template
parameter.
Now, we defer all the work to instantiating the call expression for the
UDL. This ensures that constant evaluation occurs at compile time
rather than deferring until runtime.
Fixes Issue 54578.
This information isn't preserved in the DWARF description of function
types (though probably should be - it's preserved on the function
declarations/definitions themselves through the DW_AT_noreturn attribute
- but we should move or also include that in the subroutine type itself
too - but for now, with it not being there, the DWARF is lossy and
can't be reconstructed)
Poison trivial class members one-by-one in the reverse order of their
construction, instead of all-at-once at the very end.
For example, in the following code access to `x` from `~B` will
produce an undefined value.
struct A {
struct B b;
int x;
};
Reviewed By: kda
Differential Revision: https://reviews.llvm.org/D119600
-fsanitize-memory-use-after-dtor detects memory access after a
subobject is destroyed but its memory is not yet deallocated.
This is done by poisoning each object memory near the end of its destructor.
Subobjects (members and base classes) do this in their respective
destructors, and the parent class does the same for its members with
trivial destructors.
Inexplicably, base classes with trivial destructors are not handled at
all. This change fixes this oversight by adding the base class poisoning logic
to the parent class destructor.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D119300
This is a preliminary patch ahead of D119792 (I'll rebase that one on top of this).
This shows what Clang's _current_ behaviour is for calculating NRVO in various
common cases. Then, in D119792 (and future patches), I'll be able to demostrate
exactly how LLVM IR for each of these cases changes.
Reviewed By: Quuxplusone
Differential Revision: https://reviews.llvm.org/D119927
Includes verifier changes checking the elementtype, clang codegen
changes to emit the elementtype, and ISel changes using the elementtype.
Basically the same as D120527.
Reviewed By: #opaque-pointers, nikic
Differential Revision: https://reviews.llvm.org/D121847
Includes verifier changes checking the elementtype, clang codegen
changes to emit the elementtype, and ISel changes using the elementtype.
Reviewed By: #opaque-pointers, nikic
Differential Revision: https://reviews.llvm.org/D120527
The existing module symbol mangling scheme turns out to be
undemangleable. It is also desirable to switch to the
strong-ownership model as the hoped-for C++17 compatibility turns out
to be fragile, and we also now have a better way of controlling that.
The issue is captured on the ABI list at:
https://github.com/itanium-cxx-abi/cxx-abi/issues/134
A document describing the issues and new mangling is at:
https://drive.google.com/file/d/1qQjqptzOFT_lfXH8L6-iD9nCRi34wjft/view
This patch is the code-generation part. I have a demangler too, but
that patch is based on some to-be-landed refactoring of the demangler.
The old mangling is unceremoniously dropped. No backwards
compatibility, no deprectated old-mangling flag. It was always
labelled experimental. (Old and new manglings cannot be confused.)
Reviewed By: ChuanqiXu
Differential Revision: https://reviews.llvm.org/D118352
We previously had logic to disable pthreads, set the ThreadModel to Single, and
disable thread-safe statics when the atomics target features is disabled, since
that means that the resulting program will not be used in a threaded context.
Similarly check for the presence of the bulk-memory feature, since that is also
necessary to produce multithreaded programs.
Differential Revision: https://reviews.llvm.org/D121014
This patch adds -Wno-strict-prototypes to all of the test cases that
use functions without prototypes, but not as the primary concern of the
test. e.g., attributes testing whether they can/cannot be applied to a
function without a prototype, etc.
This is done in preparation for enabling -Wstrict-prototypes by
default.
This flag was previously renamed `enable_noundef_analysis` to
`disable-noundef-analysis,` which is not a conventional name. (Driver and
CC1's boolean options are using [no-] prefix)
As discussed at https://reviews.llvm.org/D105169, this patch reverts its
name to `[no-]enable_noundef_analysis` and enables noundef-analysis as
default.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D119998
Currently we are not emitting debug-info for all cases of structured bindings a
C++17 feature which allows us to bind names to subobjects in an initializer.
A structured binding is represented by a DecompositionDecl AST node and the
binding are represented by a BindingDecl. It looks the original implementation
only covered the tuple like case which be represented by a DeclRefExpr which
contains a VarDecl.
If the binding is to a subobject of the struct the binding will contain a
MemberExpr and in the case of arrays it will contain an ArraySubscriptExpr.
This PR adds support emitting debug-info for the MemberExpr and ArraySubscriptExpr
cases as well as llvm and lldb tests for these cases as well as the tuple case.
Differential Revision: https://reviews.llvm.org/D119178
In our downstream, we discovered that the that the .* wildcard
in debug-info-hotpatch.cpp (added https://reviews.llvm.org/D116511)
ended up matching the entire line on our Windows configurations, causing
the -function-padmin check to already be consumed. After digging into it
we weren't able to find any sort of reason why the platform would matter
here, however we suspect there must be some difference in the regex
matcher between systems.
This NFC patch replaces the regex with a more conservative regex that
prevents this from happening by replacing the . match with an 'everything
but double-quote match, [^"].
https://reviews.llvm.org/D120066
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,
void func();
becomes
void func(void);
This is the ninth batch of tests being updated (there are a
significant number of other tests left to be updated).
Due to the way type units work, this would lead to a declaration in a
type unit of a local type in a CU - which is ambiguous. Rather than
trying to resolve that relative to the CU that references the type unit,
let's just not try to simplify these names.
Longer term this should be fixed by not putting the template
instantiation in a type unit to begin with - since it references an
internal linkage type, it can't legitimately be duplicated/in more than
one translation unit, so skip the type unit overhead. (but the right fix
for that is to move type unit management into a DICompositeType flag
(dropping the "identifier" field is not a perfect solution since it
breaks LLVM IR linking decl/def merging during IR linking))
Lambda names aren't entirely canonical (as demonstrated by the
cross-project-test added here) at the moment (we should fix that for a
bunch of reasons) - even if the template referencing them is
non-simplified, other names referencing /that/ template can't be
simplified either because type units might cause a different template to
be picked up that would conflict with the expected name.
(other than for roundtripping precision, it'd be OK to simplify types
that reference types that reference lambdas - but best be consistent
between the roundtrip/verify mode and the actual simplified template
names mode)
When not going through the main Clang->LLVM type cache, we'd
accidentally create multiple different opaque types for a member pointer
type.
This allows us to remove the -verify-type-cache flag now that
check-clang passes with it on. We can do the verification in expensive
builds. Previously microsoft-abi-member-pointers.cpp was failing with
-verify-type-cache.
I suspect that there may be more issues when we have multiple member
pointer types and we clear the cache, but we can leave that for later.
Followup to D118744.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D119215
Take the following as an example
struct z {
z (*p)();
};
z f();
When we attempt to get the LLVM type of f, we recurse into z. z itself
has a function pointer with the same type as f. Given the recursion,
Clang simply treats z::p as a pointer to an empty struct `{}*`. The
LLVM type of f is as expected. So we have two different potential
LLVM types for a given Clang type. If we store one of those into the
cache, when we access the cache with a different context (e.g. we
are/aren't recursing on z) we may get an incorrect result. There is some
attempt to clear the cache in these cases, but it doesn't seem to handle
all cases.
This change makes it so we only use the cache when we are not in any
sort of function context, i.e. `noRecordsBeingLaidOut() &&
FunctionsBeingProcessed.empty()`, which are the cases where we may
decide to choose a different LLVM type for a given Clang type. LLVM
types for builtin types are never recursive so they're always ok.
This allows us to clear the type cache less often (as seen with the
removal of one of the calls to `TypeCache.clear()`). We
still need to clear it when we use a placeholder type then replace it
later with the final type and other dependent types need to be
recalculated.
I've added a check that the cached type matches what we compute. It
triggered in this test case without the fix. It's currently not
check-clang clean so it's not on by default for something like expensive
checks builds.
This change uncovered another issue where the LLVM types for an argument
and its local temporary don't match. For example in type-cache-3, when
expanding z::dc's argument into a temporary alloca, we ConvertType() the
type of z::p which is `void ({}*)*`, which doesn't match the alloca GEP
type of `{}*`.
No noticeable compile time changes:
https://llvm-compile-time-tracker.com/compare.php?from=3918dd6b8acf8c5886b9921138312d1c638b2937&to=50bdec9836ed40e38ece0657f3058e730adffc4c&stat=instructionsFixes#53465.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D118744
After fa87fa97fb79, this was no longer guaranteed to be the cleanup
just added by this code, if IsEHCleanup got disabled. Instead, use
stable_begin(), which _is_ guaranteed to be the cleanup just added.
This caused a crash when a object that is callee destroyed (e.g. with the MS ABI) was passed in a call from a noexcept function.
Added a test to verify.
Fixes: fa87fa97fb79
Even if the reference itself is dllexport, the temporary should not be.
In fact, we're already giving it internal linkage, so dllexporting it
is not just wasteful, but will fail to link, as in the example below:
$ cat /tmp/a.cc
void _DllMainCRTStartup() {}
const int __declspec(dllexport) &foo = 42;
$ clang-cl -fuse-ld=lld /tmp/a.cc /Zl /link /dll /out:a.dll
lld-link: error: <root>: undefined symbol: int const &foo::$RT1
Differential revision: https://reviews.llvm.org/D118980
EHTerminateScope is used to implement C++ noexcept semantics. Per C++
[except.terminate], it is implemented-defined whether no, some, or all
cleanups are run prior to terminatation.
Therefore, the code to run cleanups on the way towards termination is
unnecessary, and may be omitted.
After this change, we will still run some cleanups: any cleanups in a
function called from the noexcept function will continue to run, while
those in the noexcept function itself will not.
(Commit attempt 2: check InnermostEHScope != stable_end() before accessing it.)
Differential Revision: https://reviews.llvm.org/D113620
When we don't enable atomics we completely disabled threading in
which case there is no point in generating thread safe code for
static initialization.
This should always be safe because, in WebAssembly, it is not
possible to link object compiled without the atomics feature into a
mutli-threaded program.
See https://github.com/emscripten-core/emscripten/pull/16152
Differential Revision: https://reviews.llvm.org/D118571
ConstStructBuilder::Finalize in CGExprConstant.ccp assumes that the
passed in QualType is a RecordType. In some instances, the type is a
reference to a RecordType and the reference needs to be removed first.
Differential Revision: https://reviews.llvm.org/D117376
Part of the _BitInt feature in C2x
(http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2763.pdf) is a new
macro in limits.h named BITINT_MAXWIDTH that can be used to determine
the maximum width of a bit-precise integer type. This macro must expand
to a value that is at least as large as ULLONG_WIDTH.
This adds an implementation-defined macro named __BITINT_MAXWIDTH__ to
specify that value, which is used by limits.h for the standard macro.
This also limits the maximum bit width to 128 bits because backends do
not currently support all mathematical operations (such as division) on
wider types yet. This maximum is expected to be increased in the future.
Problem: Migration to new PM broke flatten attribute.
This is one use case why LLVM should support inlining call-site with alwaysinline. The flatten attribute is nowdays broken, so we should either land patch like this one or remove everything related to flatten attribute from Clang.
Second use case is something like "per call site inlining intrinsics" to control inlining even more; mentioned in
https://lists.llvm.org/pipermail/cfe-dev/2018-September/059232.html
Fixes https://github.com/llvm/llvm-project/issues/53360
Reviewed By: aeubanks
Differential Revision: https://reviews.llvm.org/D117965
This patch adds support for the MSVC /HOTPATCH flag: https://docs.microsoft.com/sv-se/cpp/build/reference/hotpatch-create-hotpatchable-image?view=msvc-170&viewFallbackFrom=vs-2019
The flag is translated to a new -fms-hotpatch flag, which in turn adds a 'patchable-function' attribute for each function in the TU. This is then picked up by the PatchableFunction pass which would generate a TargetOpcode::PATCHABLE_OP of minsize = 2 (which means the target instruction must resolve to at least two bytes). TargetOpcode::PATCHABLE_OP is only implemented for x86/x64. When targetting ARM/ARM64, /HOTPATCH isn't required (instructions are always 2/4 bytes and suitable for hotpatching).
Additionally, when using /Z7, we generate a 'hot patchable' flag in the CodeView debug stream, in the S_COMPILE3 record. This flag is then picked up by LLD (or link.exe) and is used in conjunction with the linker /FUNCTIONPADMIN flag to generate extra space before each function, to accommodate for live patching long jumps. Please see: d703b92296/lld/COFF/Writer.cpp (L1298)
The outcome is that we can finally use Live++ or Recode along with clang-cl.
NOTE: It seems that MSVC cl.exe always enables /HOTPATCH on x64 by default, although if we did the same I thought we might generate sub-optimal code (if this flag was active by default). Additionally, MSVC always generates a .debug$S section and a S_COMPILE3 record, which Clang doesn't do without /Z7. Therefore, the following MSVC command-line "cl /c file.cpp" would have to be written with Clang such as "clang-cl /c file.cpp /HOTPATCH /Z7" in order to obtain the same result.
Depends on D43002, D80833 and D81301 for the full feature.
Differential Revision: https://reviews.llvm.org/D116511
When adding new attributes, existing attributes are dropped. While
this appears to be a longstanding issue, this was highlighted by D105169
which dropped a lot of attributes due to adding the new noundef
attribute.
Ahmed Bougacha (@ab) tracked down the issue and provided the fix in
CGCall.cpp. I bundled it up and updated the tests.
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
