Today the optimization is limited to:
- `[ClassName alloc]`
- `[self alloc]` when within a class method
However it means that when code is written this way:
```
@interface MyObject
- (id)copyWithZone:(NSZone *)zone
{
return [[self.class alloc] _initWith...];
}
@end
```
... then the optimization doesn't kick in and `+[NSObject alloc]` ends
up in IMP caches where it could have been avoided. It turns out that
`+alloc` -> `+[NSObject alloc]` is the most cached SEL/IMP pair in the
entire platform which is rather silly).
There's two theoretical risks allowing this optimization:
1. if the receiver is nil (which it can't be today), but it turns out
that `objc_alloc()`/`objc_alloc_init()` cope with a nil receiver,
2. if the `Clas` type for the receiver is a lie. However, for such a
code to work today (and not fail witn an unrecognized selector
anyway) you'd have to have implemented the `-alloc` **instance
method**.
Fortunately, `objc_alloc()` doesn't assume that the receiver is a
Class, it basically starts with a test that is similar to
`if (receiver->isa->bits & hasDefaultAWZ) { /* fastpath */ }`.
This bit is only set on metaclasses by the runtime, so if an instance
is passed to this function by accident, its isa will fail this test,
and `objc_alloc()` will gracefully fallback to `objc_msgSend()`.
The one thing `objc_alloc()` doesn't support is tagged pointer
instances. None of the tagged pointer classes implement an instance
method called `'alloc'` (actually there's a single class in the
entire Apple codebase that has such a method).
Differential Revision: https://reviews.llvm.org/D71682
Radar-Id: rdar://problem/58058316
Reviewed-By: Akira Hatanaka
Signed-off-by: Pierre Habouzit <phabouzit@apple.com>
AggValueSlot
This reapplies 8a5b7c3570 after a null
dereference bug in CGOpenMPRuntime::emitUserDefinedMapper.
Original commit message:
This is needed for the pointer authentication work we plan to do in the
near future.
a63a81bd99/clang/docs/PointerAuthentication.rst
__attribute__((objc_direct)) is an attribute on methods declaration, and
__attribute__((objc_direct_members)) on implementation, categories or
extensions.
A `direct` property specifier is added (@property(direct) type name)
These attributes / specifiers cause the method to have no associated
Objective-C metadata (for the property or the method itself), and the
calling convention to be a direct C function call.
The symbol for the method has enforced hidden visibility and such direct
calls are hence unreachable cross image. An explicit C function must be
made if so desired to wrap them.
The implicit `self` and `_cmd` arguments are preserved, however to
maintain compatibility with the usual `objc_msgSend` semantics,
3 fundamental precautions are taken:
1) for instance methods, `self` is nil-checked. On arm64 backends this
typically adds a single instruction (cbz x0, <closest-ret>) to the
codegen, for the vast majority of the cases when the return type is a
scalar.
2) for class methods, because the class may not be realized/initialized
yet, a call to `[self self]` is emitted. When the proper deployment
target is used, this is optimized to `objc_opt_self(self)`.
However, long term we might want to emit something better that the
optimizer can reason about. When inlining kicks in, these calls
aren't optimized away as the optimizer has no idea that a single call
is really necessary.
3) the calling convention for the `_cmd` argument is changed: the caller
leaves the second argument to the call undefined, and the selector is
loaded inside the body when it's referenced only.
As far as error reporting goes, the compiler refuses:
- making any overloads direct,
- making an overload of a direct method,
- implementations marked as direct when the declaration in the
interface isn't (the other way around is allowed, as the direct
attribute is inherited from the declaration),
- marking methods required for protocol conformance as direct,
- messaging an unqualified `id` with a direct method,
- forming any @selector() expression with only direct selectors.
As warnings:
- any inconsistency of direct-related calling convention when
@selector() or messaging is used,
- forming any @selector() expression with a possibly direct selector.
Lastly an `objc_direct_members` attribute is added that can decorate
`@implementation` blocks and causes methods only declared there (and in
no `@interface`) to be automatically direct. When decorating an
`@interface` then all methods and properties declared in this block are
marked direct.
Radar-ID: rdar://problem/2684889
Differential Revision: https://reviews.llvm.org/D69991
Reviewed-By: John McCall
This patch is motivated by (and factored out from)
https://reviews.llvm.org/D66121 which is a debug info bugfix. Starting
with DWARF 5 all Objective-C methods are nested inside their
containing type, and that patch implements this for synthesized
Objective-C properties.
1. SemaObjCProperty populates a list of synthesized accessors that may
need to inserted into an ObjCImplDecl.
2. SemaDeclObjC::ActOnEnd inserts forward-declarations for all
accessors for which no override was provided into their
ObjCImplDecl. This patch does *not* synthesize AST function
*bodies*. Moving that code from the static analyzer into Sema may
be a good idea though.
3. Places that expect all methods to have bodies have been updated.
I did not update the static analyzer's inliner for synthesized
properties to point back to the property declaration (see
test/Analysis/Inputs/expected-plists/nullability-notes.m.plist), which
I believed to be more bug than a feature.
Differential Revision: https://reviews.llvm.org/D68108
rdar://problem/53782400
We previously failed to treat an array with an instantiation-dependent
but not value-dependent bound as being an instantiation-dependent type.
We now track the array bound expression as part of a constant array type
if it's an instantiation-dependent expression.
llvm-svn: 373685
'objc_alloc(self)'
Also convert '[[self alloc] init]' in a class method to a call to
'objc_alloc_init(self)'.
rdar://problem/50855121
Differential Revision: https://reviews.llvm.org/D62643
llvm-svn: 362521
necessary.
Prior to r349952, clang used to call objc_msgSend when sending a release
messages, emitting an invoke instruction instead of a call instruction
when it was necessary to catch an exception. That changed in r349952
because runtime function objc_release is called as a nounwind function,
which broke programs that were overriding the dealloc method and
throwing an exception from it. This patch restores the behavior prior to
r349952.
rdar://problem/50253394
Differential Revision: https://reviews.llvm.org/D61803
llvm-svn: 360474
named metadata.
This fixes a bug where ARC contract wasn't inserting the retainRV
marker when LTO was enabled, which caused objects returned from a
function to be auto-released.
rdar://problem/49464214
Differential Revision: https://reviews.llvm.org/D60302
llvm-svn: 358048
with notail on x86-64.
On x86-64, the epilogue code inserted before the tail jump blocks the
autoreleased return optimization.
rdar://problem/38675807
Differential Revision: https://reviews.llvm.org/D59656
llvm-svn: 356705
expression inside the parentheses is a valid UTF-8 string literal.
Previously clang emitted an expression like @("abc") as a message send
to stringWithUTF8String. This commit makes clang emit the boxed
expression as a compile-time constant instead.
This commit also has the effect of silencing the nullable-to-nonnull
conversion warning clang started emitting after r317727, which
originally motivated this commit (see https://oleb.net/2018/@keypath).
rdar://problem/42684601
Differential Revision: https://reviews.llvm.org/D58729
llvm-svn: 355662
initializes a local auto variable or is assigned to a local auto
variable that is declared in the scope that introduced the block
literal.
rdar://problem/13289333
https://reviews.llvm.org/D58514
llvm-svn: 355012
ObjCMessageExpr::getInstanceReceiver returns nullptr if the receiver
is 'super'. Make this check more strict, since we don't care about
messages to super here.
rdar://48247290
llvm-svn: 354826
This provides a code size win on the caller side, since the init
message send is done in the runtime function.
rdar://44987038
Differential revision: https://reviews.llvm.org/D57936
llvm-svn: 354056
The various EltSize, Offset, DataLayout, and StructLayout arguments
are all computable from the Address's element type and the DataLayout
which the CGBuilder already has access to.
After having previously asserted that the computed values are the same
as those passed in, now remove the redundant arguments from
CGBuilder's Create*GEP functions.
Differential Revision: https://reviews.llvm.org/D57767
llvm-svn: 353629
Emit{Nounwind,}RuntimeCall{,OrInvoke} have been modified to take a
FunctionCallee as an argument, and CreateRuntimeFunction has been
modified to return a FunctionCallee. All callers have been updated.
Additionally, CreateBuiltinFunction is removed, as it was redundant
with CreateRuntimeFunction after some previous changes.
Differential Revision: https://reviews.llvm.org/D57668
llvm-svn: 353184
edge cases.
Currently, EmitCall emits a call instruction with a function type
derived from the pointee-type of the callee. This *should* be the same
as the type created from the CallInfo parameter, but in some cases an
incorrect CallInfo was being passed.
All of these fixes were discovered by the addition of the assert in
EmitCall which verifies that the passed-in CallInfo matches the
Callee's function type.
As far as I know, these issues caused no bugs at the moment, as the
correct types were ultimately being emitted. But, some would become
problematic when pointee types are removed.
List of fixes:
* arrangeCXXConstructorCall was passing an incorrect value for the
number of Required args, when calling an inheriting constructor
where the inherited constructor is variadic. (The inheriting
constructor doesn't actually get passed any of the user's args, but
the code was calculating it as if it did).
* arrangeFreeFunctionLikeCall was not including the count of the
pass_object_size arguments in the count of required args.
* OpenCL uses other address spaces for the "this" pointer. However,
commonEmitCXXMemberOrOperatorCall was not annotating the address
space on the "this" argument of the call.
* Destructor calls were being created with EmitCXXMemberOrOperatorCall
instead of EmitCXXDestructorCall in a few places. This was a problem
because the calling convention sometimes has destructors returning
"this" rather than void, and the latter function knows about that,
and sets up the types properly (through calling
arrangeCXXStructorDeclaration), while the former does not.
* generateObjCGetterBody: the 'objc_getProperty' function returns type
'id', but was being called as if it returned the particular
property's type. (That is of course the *dynamic* return type, and
there's a downcast immediately after.)
* OpenMP user-defined reduction functions (#pragma omp declare
reduction) can be called with a subclass of the declared type. In
such case, the call was being setup as if the function had been
actually declared to take the subtype, rather than the base type.
Differential Revision: https://reviews.llvm.org/D57664
llvm-svn: 353181
objc_alloc and objc_allocWithZone may throw exceptions if the
underlying method does. If we're in a @try block, then make sure we
emit an invoke instead of a call.
rdar://47610407
Differential revision: https://reviews.llvm.org/D57476
llvm-svn: 352687
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
r348687 converted [Foo alloc] to objc_alloc(Foo). However the objc runtime method only takes a Class, not an arbitrary pointer.
This makes sure we are messaging a class before we convert these messages.
rdar://problem/46943703
llvm-svn: 350224
It is faster to directly call the ObjC runtime for methods such as retain/release instead of sending a message to those functions.
Differential Revision: https://reviews.llvm.org/D55869
Reviewed By: rjmccall
llvm-svn: 349952
Since CallExpr::setNumArgs has been removed, it is now possible to store the
callee expression and the argument expressions of CallExpr in a trailing array.
This saves one pointer per CallExpr, CXXOperatorCallExpr, CXXMemberCallExpr,
CUDAKernelCallExpr and UserDefinedLiteral.
Given that CallExpr is used as a base of the above classes we cannot use
llvm::TrailingObjects. Instead we store the offset in bytes from the this pointer
to the start of the trailing objects and manually do the casts + arithmetic.
Some notes:
1.) I did not try to fit the number of arguments in the bit-fields of Stmt.
This leaves some space for future additions and avoid the discussion about
whether x bits are sufficient to hold the number of arguments.
2.) It would be perfectly possible to recompute the offset to the trailing
objects before accessing the trailing objects. However the trailing objects
are frequently accessed and benchmarks show that it is slightly faster to
just load the offset from the bit-fields. Additionally, because of 1),
we have plenty of space in the bit-fields of Stmt.
Differential Revision: https://reviews.llvm.org/D55771
Reviewed By: rjmccall
llvm-svn: 349910
All of the other constructors already take a reference to the AST context.
This avoids calling Decl::getASTContext in most cases. Additionally move
the definition of the constructor from Expr.h to Expr.cpp since it is calling
DeclRefExpr::computeDependence. NFC.
llvm-svn: 349901
Calls to this function are deleted in the ARC optimizer. However when the ARC
optimizer was updated to use intrinsics instead of functions (r349534), the corresponding
clang change (r349535) to use intrinsics missed this one so it wasn't being deleted.
llvm-svn: 349782
It is faster to directly call the ObjC runtime for methods such as alloc/allocWithZone instead of sending a message to those functions.
This patch adds support for converting messages to alloc/allocWithZone to their equivalent runtime calls.
Tests included for the positive case of applying this transformation, negative tests that we ensure we only convert "alloc" to objc_alloc, not "alloc2", and also a driver test to ensure we enable this only for supported runtime versions.
Reviewed By: rjmccall
https://reviews.llvm.org/D55349
llvm-svn: 348687
Fix places where the return type of a FunctionDecl was being used in
place of the function type
FunctionDecl::Create() takes as its T parameter the type of function
that should be created, not the return type. Passing in the return type
looks to have been copypasta'd around a bit, but the number of correct
usages outweighs the incorrect ones so I've opted for keeping what T is
the same and fixing up the call sites instead.
This fixes a crash in Clang when attempting to compile the following
snippet of code with -fblocks -fsanitize=function -x objective-c++ (my
original repro case):
void g(void(^)());
void f()
{
__block int a = 0;
g(^(){ a++; });
}
as well as the following which only requires -fsanitize=function -x c++:
void f(char * buf)
{
__builtin_os_log_format(buf, "");
}
Patch by: Ben (bobsayshilol)
Differential revision: https://reviews.llvm.org/D53263
llvm-svn: 346601
Failed assertion is
> Assertion failed: ((ND->isUsed(false) || !isa<VarDecl>(ND) || !E->getLocation().isValid()) && "Should not use decl without marking it used!"), function EmitDeclRefLValue, file llvm-project/clang/lib/CodeGen/CGExpr.cpp, line 2437.
`EmitDeclRefLValue` mentions
> // A DeclRefExpr for a reference initialized by a constant expression can
> // appear without being odr-used. Directly emit the constant initializer.
The fix is to use the similar approach for non-references as for references. It
is achieved by trying to emit a constant before we attempt to load non-odr-used
variable as LValue.
rdar://problem/40650504
Reviewers: ahatanak, rjmccall
Reviewed By: rjmccall
Subscribers: dexonsmith, erik.pilkington, cfe-commits
Differential Revision: https://reviews.llvm.org/D53674
llvm-svn: 345903
Only store the NRVO candidate if needed in ReturnStmt.
A good chuck of all of the ReturnStmt have no NRVO candidate
(more than half when parsing all of Boost). For all of them
this saves one pointer. This has no impact on children().
Differential Revision: https://reviews.llvm.org/D53716
Reviewed By: rsmith
llvm-svn: 345605
This is similar to the LLVM change https://reviews.llvm.org/D46290.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46320
llvm-svn: 331834
the tail padding is not reused.
We track on the AggValueSlot (and through a couple of other
initialization actions) whether we're dealing with an object that might
share its tail padding with some other object, so that we can avoid
emitting stores into the tail padding if that's the case. We still
widen stores into tail padding when we can do so.
Differential Revision: https://reviews.llvm.org/D45306
llvm-svn: 329342
The inline assembly generated for the ARC autorelease elision marker
must have a funclet token if it's emitted inside a funclet, otherwise
the inline assembly (and all subsequent code in the funclet) will be
marked unreachable. r324689 fixed this issue for regular inline assembly
blocks.
Note that clang only emits the marker at -O0, so this only fixes that
case. The optimizations case (where the marker is emitted by the
backend) will be fixed in a separate change.
Differential Revision: https://reviews.llvm.org/D44640
llvm-svn: 327892
This patch uses the infrastructure added in r326307 for enabling
non-trivial fields to be declared in C structs to allow __weak fields in
C structs in ARC.
This recommits r327206, which was reverted because it caused
module-enabled builders to fail. I discovered that the
CXXRecordDecl::CanPassInRegisters flag wasn't being set correctly in
some cases after I moved it to RecordDecl.
Thanks to Eric Liu for helping me investigate the bug.
rdar://problem/33599681
https://reviews.llvm.org/D44095
llvm-svn: 327870
This patch uses the infrastructure added in r326307 for enabling
non-trivial fields to be declared in C structs to allow __weak fields in
C structs in ARC.
rdar://problem/33599681
Differential Revision: https://reviews.llvm.org/D44095
llvm-svn: 327206
Pierre Habouzit