Currently, if clang::isBetterOverloadCandidate encounters an enable_if
attribute on either candidate that it's inspecting, it will ignore all
lower priority attributes (e.g. pass_object_size). This is problematic
in cases like:
```
void foo(char *c) __attribute__((enable_if(1, "")));
void foo(char *c __attribute__((pass_object_size(0))))
__attribute__((enable_if(1, "")));
```
...Because we would ignore the pass_object_size attribute in the second
`foo`, and consider any call to `foo` to be ambiguous.
This patch makes overload resolution consult further tiebreakers (e.g.
pass_object_size) if two candidates have equally good enable_if
attributes.
llvm-svn: 269005
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
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
George Burgess IV