This attribute is used to prevent tail-call optimizations to the marked
function. For example, in the following piece of code, foo1 will not be
tail-call optimized:
int __attribute__((not_tail_called)) foo1(int);
int foo2(int a) {
return foo1(a); // Tail-call optimization is not performed.
}
The attribute has effect only on statically bound calls. It has no
effect on indirect calls. Also, virtual functions and objective-c
methods cannot be marked as 'not_tail_called'.
rdar://problem/22667622
Differential Revision: http://reviews.llvm.org/D12922
llvm-svn: 252369
internal linkage entities in different modules from r250884 to apply to all
names, not just function names.
This is really awkward: we don't want to merge internal-linkage symbols from
separate modules, because they might not actually be defining the same entity.
But we don't want to reject programs that use such an ambiguous symbol if those
internal-linkage symbols are in fact equivalent. For now, we're resolving the
ambiguity by picking one of the equivalent definitions as an extension.
llvm-svn: 252063
Summary: Diagnose when the 'concept' specifier is used on a typedef or function parameter.
Reviewers: rsmith, hubert.reinterpretcast, aaron.ballman, faisalv
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D14316
llvm-svn: 252061
This new builtin template allows for incredibly fast instantiations of
templates like std::integer_sequence.
Performance numbers follow:
My work station has 64 GB of ram + 20 Xeon Cores at 2.8 GHz.
__make_integer_seq<std::integer_sequence, int, 90000> takes 0.25
seconds.
std::make_integer_sequence<int, 90000> takes unbound time, it is still
running. Clang is consuming gigabytes of memory.
Differential Revision: http://reviews.llvm.org/D13786
llvm-svn: 252036
Now that the properties created within Objective-C class extensions go
into the extension themselves, we don't need any of the extra
complexity here.
llvm-svn: 251949
particular don't assume that two declarations of the same kind in the same
context are declaring the same entity. That's not true when the same name is
declared multiple times as internal-linkage symbols within a module.
(getCanonicalDecl is cheap now, so we can just use it here.)
llvm-svn: 251898
A 'readonly' Objective-C property declared in the primary class can
effectively be shadowed by a 'readwrite' property declared within an
extension of that class, so long as the types and attributes of the
two property declarations are compatible.
Previously, this functionality was implemented by back-patching the
original 'readonly' property to make it 'readwrite', destroying source
information and causing some hideously redundant, incorrect
code. Simplify the implementation to express how this should actually
be modeled: as a separate property declaration in the extension that
shadows (via the name lookup rules) the declaration in the primary
class. While here, correct some broken Fix-Its, eliminate a pile of
redundant code, clean up the ARC migrator's handling of properties
declared in extensions, and fix debug info's naming of methods that
come from categories.
A wonderous side effect of doing this write is that it eliminates the
"AddedObjCPropertyInClassExtension" method from the AST mutation
listener, which in turn eliminates the last place where we rewrite
entire declarations in a chained PCH file or a module file. This
change (which fixes rdar://problem/18475765) will allow us to
eliminate the rewritten-decls logic from the serialization library,
and fixes a crash (rdar://problem/23247794) illustrated by the
test/PCH/chain-categories.m example.
llvm-svn: 251874
We permit implicit conversion from pointer-to-function to
pointer-to-object when -fms-extensions is specified. This is rather
unfortunate, move this into -fms-compatibility and only permit it within
system headers unless -Wno-error=microsoft-cast is specified.
llvm-svn: 251738
Handle blocks in the tree transform for the typo correction as otherwise, the
capture may miss. This would trigger an assertion. Thanks to Doug Gregor for
the help with this!
Fixes PR25001.
llvm-svn: 251729
GCC has a warning called -Wdouble-promotion, which warns you when
an implicit conversion increases the width of a floating point type.
This is useful when writing code for architectures that can perform
hardware FP ops on floats, but must fall back to software emulation for
larger types (i.e. double, long double).
This fixes PR15109 <https://llvm.org/bugs/show_bug.cgi?id=15109>.
Thanks to Carl Norum for the patch!
llvm-svn: 251588
Fake arguments are automatically handled for serialization, cloning,
and other representational tasks, but aren't included in pretty-printing
or parsing (should we eventually ever automate that).
This is chiefly useful for attributes that can be written by the
user, but which are also frequently synthesized by the compiler,
and which we'd like to remember details of the synthesis for.
As a simple example, use this to narrow the cases in which we were
generating a specialized note for implicitly unavailable declarations.
llvm-svn: 251469
1. Make the warning more strict in C mode. r172696 added code to suppress
warnings from macro expansions in system headers, which checks
`SourceMgr.isMacroBodyExpansion(E->IgnoreParens()->getExprLoc())`. Consider
this snippet:
#define FOO(x) (x)
void f(int a) {
FOO(a);
}
In C, the line `FOO(a)` is an `ImplicitCastExpr(ParenExpr(DeclRefExpr))`,
while it's just a `ParenExpr(DeclRefExpr)` in C++. So in C++,
`E->IgnoreParens()` returns the `DeclRefExpr` and the check tests the
SourceLoc of `a`. In C, the `ImplicitCastExpr` has the effect of checking the
SourceLoc of `FOO`, which is a macro body expansion, which causes the
diagnostic to be skipped. It looks unintentional that clang does different
things for C and C++ here, so use `IgnoreParenImpCasts` instead of
`IgnoreParens` here. This has the effect of the warning firing more often
than previously in C code – it now fires as often as it fires in C++ code.
2. Suppress the warning if it would warn on `UNREFERENCED_PARAMETER`.
`UNREFERENCED_PARAMETER` is a commonly used macro on Windows and it happens
to uselessly trigger -Wunused-value. As discussed in the thread
"rfc: winnt.h's UNREFERENCED_PARAMETER() vs clang's -Wunused-value" on
cfe-dev, fix this by special-casing this specific macro. (This costs a string
comparison and some fast-path lexing per warning, but the warning is emitted
rarely. It fires once in Windows.h itself, so this code runs at least once
per TU including Windows.h, but it doesn't run hundreds of times.)
http://reviews.llvm.org/D13969
llvm-svn: 251441
allow them to be written in certain kinds of user declaration and
diagnose on the use-site instead.
Also, improve and fix some diagnostics relating to __weak and
properties.
rdar://23228631
llvm-svn: 251384
Summary:
In `MismatchingNewDeleteDetector::analyzeInClassInitializer`, if
`Field`'s initializer expression is null, lookup the field in
implicit instantiation, and use found field's the initializer.
Reviewers: rsmith, rtrieu
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D9898
llvm-svn: 251335
Previously, __weak was silently accepted and ignored in MRC mode.
That makes this a potentially source-breaking change that we have to
roll out cautiously. Accordingly, for the time being, actual support
for __weak references in MRC is experimental, and the compiler will
reject attempts to actually form such references. The intent is to
eventually enable the feature by default in all non-GC modes.
(It is, of course, incompatible with ObjC GC's interpretation of
__weak.)
If you like, you can enable this feature with
-Xclang -fobjc-weak
but like any -Xclang option, this option may be removed at any point,
e.g. if/when it is eventually enabled by default.
This patch also enables the use of the ARC __unsafe_unretained qualifier
in MRC. Unlike __weak, this is being enabled immediately. Since
variables are essentially __unsafe_unretained by default in MRC,
the only practical uses are (1) communication and (2) changing the
default behavior of by-value block capture.
As an implementation matter, this means that the ObjC ownership
qualifiers may appear in any ObjC language mode, and so this patch
removes a number of checks for getLangOpts().ObjCAutoRefCount
that were guarding the processing of these qualifiers. I don't
expect this to be a significant drain on performance; it may even
be faster to just check for these qualifiers directly on a type
(since it's probably in a register anyway) than to do N dependent
loads to grab the LangOptions.
rdar://9674298
llvm-svn: 251041
headers. If those headers end up being textually included twice into the same
module, we get ambiguity errors.
Work around this by downgrading the ambiguity error to a warning if multiple
identical internal-linkage functions appear in an overload set, and just pick
one of those functions as the lookup result.
llvm-svn: 250884
This time, I went with the first approach from
http://reviews.llvm.org/D6700, where clang actually attempts to form an
implicit member reference from an UnresolvedLookupExpr. We know that
there are only two possible outcomes at this point, a DeclRefExpr of the
FieldDecl or an error, but its safer to reuse the existing machinery for
this.
llvm-svn: 250856
Microsoft's ATL headers make use of this MSVC extension, add support for
it and issue a diagnostic under -Wmicrosoft-exception-spec.
This fixes PR25265.
llvm-svn: 250854
Clang will now accept this valid C++11 code:
struct A { int field; };
struct B : A {
using A::field;
enum { TheSize = sizeof(field) };
};
Previously we would classify the 'field' reference as something other
than a field, and then forget to apply the C++11 rule to allow
non-static data member references in unevaluated contexts.
This usually arises in class templates that want to reference fields of
a dependent base in an unevaluated context outside of an instance
method. Such contexts do not allow references to 'this', so the only way
to access the field is with a using decl and an implicit member
reference.
llvm-svn: 250839
Summary: It breaks the build for the ASTMatchers
Subscribers: klimek, cfe-commits
Differential Revision: http://reviews.llvm.org/D13893
llvm-svn: 250827
This reverts commit r250592.
It has issues around unevaluated contexts, like this:
template <class T> struct A { T i; };
template <class T>
struct B : A<T> {
using A<T>::i;
typedef decltype(i) U;
};
template struct B<int>;
llvm-svn: 250774
During the initial template parse for this code, 'member' is unresolved
and we don't know anything about it:
struct A { int member };
template <typename T>
struct B : public T {
using T::member;
static void f() {
(void)member; // Could be static or non-static.
}
};
template class B<A>;
The pattern declaration contains an UnresolvedLookupExpr rather than an
UnresolvedMemberExpr because `f` is static, and `member` should never be
a field. However, if the code is invalid, it may become a field, in
which case we should diagnose it.
Reviewers: rjmccall, rsmith
Differential Revision: http://reviews.llvm.org/D6700
llvm-svn: 250592
Previously, our logic when taking the address of an overloaded function
would not consider enable_if attributes, so long as all of the enable_if
conditions on a given candidate were true. So, two functions with
identical signatures (one with enable_if attributes, the other without),
would be considered equally good overloads. If we were calling the
function instead of taking its address, then the function with enable_if
attributes would be preferred.
This patch makes us prefer the candidate with enable_if regardless of if
we're calling or taking the address of an overloaded function.
Differential Revision: http://reviews.llvm.org/D13795
llvm-svn: 250486
context (but otherwise at the top level) to be disabled, to support use of C++
standard library implementations that (legitimately) mark their <blah.h>
headers as being C++ headers from C libraries that wrap things in 'extern "C"'
a bit too enthusiastically.
llvm-svn: 250137
This fixes a bug where one can take the address of a conditionally
enabled function to drop its enable_if guards. For example:
int foo(int a) __attribute__((enable_if(a > 0, "")));
int (*p)(int) = &foo;
int result = p(-1); // compilation succeeds; calls foo(-1)
Overloading logic has been updated to reflect this change, as well.
Functions with enable_if attributes that are always true are still
allowed to have their address taken.
Differential Revision: http://reviews.llvm.org/D13607
llvm-svn: 250090
Fixed a bug where we'd emit multiple diagnostics if there was a problem
taking the address of an overloaded template function.
Differential Revision: http://reviews.llvm.org/D13664
llvm-svn: 250078
Craig Topper