A user reported an issue to me via email that Clang was accepting some
code that GCC was rejecting. After investigation, it turned out to be a
general problem of us failing to properly reject attributes written in
the type position in C when they don't apply to types. The root cause
was a terminology issue -- we sometimes use "CXX11Attr" to mean [[]] in
C++11 mode and sometimes [[]] in general -- and this came back to bite
us because in this particular case, it really meant [[]] in C++ mode.
I fixed the issue by introducing a new function
AttributeCommonInfo::isStandardAttributeSyntax() to represent [[]] in
either C or C++ mode.
This fix pointed out that we've had the issue in some of our existing
tests, which have all been corrected. This resolves
https://bugs.llvm.org/show_bug.cgi?id=50954.
Compute and propagate conversion kind to diagnostics helper in C++
to provide more specific diagnostics about incorrect implicit
conversions in assignments, initializations, params, etc...
Duplicated some diagnostics as errors because C++ is more strict.
Tags: #clang
Differential Revision: https://reviews.llvm.org/D74116
Before this commit, we emit unavailable errors for calls to functions during
overload resolution, and for references to all other declarations in
DiagnoseUseOfDecl. The early checks during overload resolution aren't as good as
the DiagnoseAvailabilityOfDecl based checks, as they error on the code from
PR40991. This commit fixes this by removing the early checking.
llvm.org/PR40991
rdar://48564179
Differential revision: https://reviews.llvm.org/D59394
llvm-svn: 356599
This patch extends the `overloadable` attribute to allow for one
function with a given name to not be marked with the `overloadable`
attribute. The overload without the `overloadable` attribute will not
have its name mangled.
So, the following code is now legal:
void foo(void) __attribute__((overloadable));
void foo(int);
void foo(float) __attribute__((overloadable));
In addition, this patch fixes a bug where we'd accept code with
`__attribute__((overloadable))` inconsistently applied. In other words,
we used to accept:
void foo(void);
void foo(void) __attribute__((overloadable));
But we will do this no longer, since it defeats the original purpose of
requiring `__attribute__((overloadable))` on all redeclarations of a
function.
This breakage seems to not be an issue in practice, since the only code
I could find that had this pattern often looked like:
void foo(void);
void foo(void) __attribute__((overloadable)) __asm__("foo");
void foo(int) __attribute__((overloadable));
...Which can now be simplified by simply removing the asm label and
overloadable attribute from the redeclaration of `void foo(void);`
Differential Revision: https://reviews.llvm.org/D32332
llvm-svn: 306467
We were sometimes doing a function->pointer conversion in
Sema::CheckPlaceholderExpr, which isn't the job of CheckPlaceholderExpr.
So, when we saw typeof(OverloadedFunctionName), where
OverloadedFunctionName referenced a name with only one function that
could have its address taken, we'd give back a function pointer type
instead of a function type. This is incorrect.
I kept the logic for doing the function pointer conversion in
resolveAndFixAddressOfOnlyViableOverloadCandidate because it was more
consistent with existing ResolveAndFix* methods.
llvm-svn: 302506
This patch allows us to perform incompatible pointer conversions when
resolving overloads in C. So, the following code will no longer fail to
compile (though it will still emit warnings, assuming the user hasn't
opted out of them):
```
void foo(char *) __attribute__((overloadable));
void foo(int) __attribute__((overloadable));
void callFoo() {
unsigned char bar[128];
foo(bar); // selects the char* overload.
}
```
These conversions are ranked below all others, so:
A. Any other viable conversion will win out
B. If we had another incompatible pointer conversion in the example
above (e.g. `void foo(int *)`), we would complain about
an ambiguity.
Differential Revision: https://reviews.llvm.org/D24113
llvm-svn: 280553
Give incompatible function pointer warning its own diagnostic group
but still leave it as a subgroup of incompatible-pointer-types. This is in
preparation to promote -Wincompatible-function-pointer-types to error on
darwin.
Differential Revision: https://reviews.llvm.org/D22248
rdar://problem/12907612
llvm-svn: 275907
Also includes a minor ``enable_if`` docs update.
Currently, our address-of overload machinery will only allow implicit
conversions of overloaded functions to void* in C. For example:
```
void f(int) __attribute__((overloadable));
void f(double) __attribute__((overloadable, enable_if(0, "")));
void *fp = f; // OK. This is C and the target is void*.
void (*fp2)(void) = f; // Error. This is C, but the target isn't void*.
```
This patch makes the assignment of `fp2` select the `f(int)` overload,
rather than emitting an error (N.B. you'll still get a warning about the
`fp2` assignment if you use -Wincompatible-pointer-types).
Differential Revision: http://reviews.llvm.org/D13704
llvm-svn: 264132
C allows for some implicit conversions that C++ does not, e.g. void* ->
char*. This patch teaches clang that these conversions are okay when
dealing with overloads in C.
Differential Revision: http://reviews.llvm.org/D13604
llvm-svn: 249995
standard's rule that an extern "C" declaration conflicts with any entity in the
global scope with the same name. Now we only care if the global scope entity is
a variable declaration (and so might have the same mangled name as the extern
"C" declaration). This has been reported as a standard defect.
Original commit message:
PR7927, PR16247: Reimplement handling of matching extern "C" declarations
across scopes.
When we declare an extern "C" name that is not a redeclaration of an entity in
the same scope, check whether it redeclares some extern "C" entity from another
scope, and if not, check whether it conflicts with a (non-extern-"C") entity in
the translation unit.
When we declare a name in the translation unit that is not a redeclaration,
check whether it conflicts with any extern "C" entities (possibly from other
scopes).
llvm-svn: 185281
across scopes.
When we declare an extern "C" name that is not a redeclaration of an entity in
the same scope, check whether it redeclares some extern "C" entity from another
scope, and if not, check whether it conflicts with a (non-extern-"C") entity in
the translation unit.
When we declare a name in the translation unit that is not a redeclaration,
check whether it conflicts with any extern "C" entities (possibly from other
scopes).
llvm-svn: 185229
diagnostic message are compared. If either is a substring of the other, then
no error is given. This gives rise to an unexpected case:
// expect-error{{candidate function has different number of parameters}}
will match the following error messages from Clang:
candidate function has different number of parameters (expected 1 but has 2)
candidate function has different number of parameters
It will also match these other error messages:
candidate function
function has different number of parameters
number of parameters
This patch will change so that the verification string must be a substring of
the diagnostic message before accepting. Also, all the failing tests from this
change have been corrected. Some stats from this cleanup:
87 - removed extra spaces around verification strings
70 - wording updates to diagnostics
40 - extra leading or trailing characters (typos, unmatched parens or quotes)
35 - diagnostic level was included (error:, warning:, or note:)
18 - flag name put in the warning (-Wprotocol)
llvm-svn: 146619
Fixes an assertion arising C overload analysis, but really I can't imagine
that this wouldn't cause a thousand other uncaught failures.
Fixes PR6600.
llvm-svn: 98400
not just the viable ones. This is reasonable because the most common use of
deleted functions is to exclude some implicit conversion during calls; users
therefore will want to figure out why some other options were excluded.
Started sorting overload results. Right now it just sorts by location in the
translation unit (after putting viable functions first), but we can do better than
that.
Changed bool OnlyViable parameter to PrintOverloadCandidates to an enum for better
self-documentation.
llvm-svn: 92990
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).
llvm-svn: 91446
(as GCC does), except when we've performed overload resolution and
found an unavailable function: in this case, we actually error.
Merge the checking of unavailable functions with the checking for
deprecated functions. This unifies a bit of code, and makes sure that
we're checking for unavailable functions in the right places. Also,
this check can cause an error. We may, eventually, want an option to
make "unavailable" warnings into errors.
Implement much of the logic needed for C++0x deleted functions, which
are effectively the same as "unavailable" functions (but always cause
an error when referenced). However, we don't have the syntax to
specify deleted functions yet :)
llvm-svn: 64955
any named parameters, e.g., this is accepted in C:
void f(...) __attribute__((overloadable));
although this would be rejected:
void f(...);
To do this, moved the checking of the "ellipsis without any named
arguments" condition from the parser into Sema (where it belongs anyway).
llvm-svn: 64902
to do in this area, since there are other places that reference
FunctionDecls.
Don't allow "overloadable" functions (in C) to be declared without a
prototype.
llvm-svn: 64897
given name in a given scope is marked as "overloadable", every
function declaration and definition with that same name and in that
same scope needs to have the "overloadable" attribute. Essentially,
the "overloadable" attribute is not part of attribute merging, so it
must be specified even for redeclarations. This keeps users from
trying to be too sneaky for their own good:
double sin(double) __attribute__((overloadable)); // too sneaky
#include <math.h>
Previously, this would have made "sin" overloadable, and therefore
given it a mangled name. Now, we get an error inside math.h when we
see a (re)declaration of "sin" that doesn't have the "overloadable"
attribute.
llvm-svn: 64414
Aaron Ballman