This commit adds a new attribute, "overloadable", that enables C++
function overloading in C. The attribute can only be added to function
declarations, e.g.,
int *f(int) __attribute__((overloadable));
If the "overloadable" attribute exists on a function with a given
name, *all* functions with that name (and in that scope) must have the
"overloadable" attribute. Sets of overloaded functions with the
"overloadable" attribute then follow the normal C++ rules for
overloaded functions, e.g., overloads must have different
parameter-type-lists from each other.
When calling an overloaded function in C, we follow the same
overloading rules as C++, with three extensions to the set of standard
conversions:
- A value of a given struct or union type T can be converted to the
type T. This is just the identity conversion. (In C++, this would
go through a copy constructor).
- A value of pointer type T* can be converted to a value of type U*
if T and U are compatible types. This conversion has Conversion
rank (it's considered a pointer conversion in C).
- A value of type T can be converted to a value of type U if T and U
are compatible (and are not both pointer types). This conversion
has Conversion rank (it's considered to be a new kind of
conversion unique to C, a "compatible" conversion).
Known defects (and, therefore, next steps):
1) The standard-conversion handling does not understand conversions
involving _Complex or vector extensions, so it is likely to get
these wrong. We need to add these conversions.
2) All overloadable functions with the same name will have the same
linkage name, which means we'll get a collision in the linker (if
not sooner). We'll need to mangle the names of these functions.
llvm-svn: 64336
actually *slightly* slower than the binary search. Since this is algorithmically
better, further performance tuning should be able to make this faster.
llvm-svn: 64326
for non-external names whose address becomes the template
argument. This completes C++ [temp.arg.nontype]p1.
Note that our interpretation of C++ [temp.arg.nontype]p1b3 differs
from EDG's interpretation (we're stricter, and GCC agrees with
us). They're opening a core issue about the matter.
llvm-svn: 64317
template specialization (e.g., std::vector<int> would now be
well-formed, since it relies on a default argument for the Allocator
template parameter).
This is much less interesting than one might expect, since (1) we're
not actually using the default arguments for anything important, such
as naming an actual Decl, and (2) we'll often need to instantiate the
default arguments to check their well-formedness. The real fun will
come later.
llvm-svn: 64310
pointer-to-member-data non-type template parameters. Also, get
consistent about what it means to returned a bool from
CheckTemplateArgument.
llvm-svn: 64305
non-type template parameters that are references to functions or
pointers to member functions. Did a little bit of refactoring so that
these two cases, along with the handling of non-type template
parameters that are pointers to functions, are handled by the same
path.
Also, tweaked FixOverloadedFunctionReference to cope with member
function pointers. This is a necessary step for getting all of the fun
member pointer conversions working outside of template arguments, too.
llvm-svn: 64277
non-type template parameters of pointer-to-object and
pointer-to-function type. The most fun part of this is the use of
overload resolution to pick a function from the set of overloaded
functions that comes in as a template argument.
Also, fixed two minor bugs in this area:
- We were allowing non-type template parameters of type pointer to
void.
- We weren't patching up an expression that refers to an overloaded
function set via "&f" properly.
We're still not performing complete checking of the expression to be
sure that it is referring to an object or function with external
linkage (C++ [temp.arg.nontype]p1).
llvm-svn: 64266
We handle indentation of decls better.
We Indent extern "C" { } stuff better.
We print out structure contents more often.
We handle pass indentation information into the statement printer, so that
nested things come out more indented.
We print out FieldDecls.
We print out Vars.
We print out namespaces.
We indent functions better.
llvm-svn: 64232
arguments. This commit covers checking and merging default template
arguments from previous declarations, but it does not cover the actual
use of default template arguments when naming class template
specializations.
llvm-svn: 64229
Ted Kremenek