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
- Made allocation of Stmt objects using vanilla new/delete a *compiler
error* by making this new/delete "protected" within class Stmt.
- Now the only way to allocate Stmt objects is by using the new
operator that takes ASTContext& as an argument. This ensures that
all Stmt nodes are allocated from the same (pool) allocator.
- Naturally, these two changes required that *all* creation sites for
AST nodes use new (ASTContext&). This is a large patch, but the
majority of the changes are just this mechanical adjustment.
- The above changes also mean that AST nodes can no longer be
deallocated using 'delete'. Instead, one most do
StmtObject->Destroy(ASTContext&) or do
ASTContextObject.Deallocate(StmtObject) (the latter not running the
'Destroy' method).
Along the way I also...
- Made CompoundStmt allocate its array of Stmt* using the allocator in
ASTContext (previously it used std::vector). There are a whole
bunch of other Stmt classes that need to be similarly changed to
ensure that all memory allocated for ASTs comes from the allocator
in ASTContext.
- Added a new smart pointer ExprOwningPtr to Sema.h. This replaces
the uses of llvm::OwningPtr within Sema, as llvm::OwningPtr used
'delete' to free memory instead of a Stmt's 'Destroy' method.
Big thanks to Doug Gregor for helping with the acrobatics of making
'new/delete' private and the new smart pointer ExprOwningPtr!
llvm-svn: 63997
ASTContext. This required changing all clients to pass in the ASTContext& to the
constructor of StringLiteral. I also changed all allocations of StringLiteral to
use new(ASTContext&).
Along the way, I updated a bunch of new()'s in StmtSerialization.cpp to use the
allocator from ASTContext& (not complete).
llvm-svn: 63958
- Changes Lookup*Name functions to return NamedDecls, instead of
Decls. Unfortunately my recent statement that it will simplify lot of
code, was not quite right, but it simplifies some...
- Makes MergeLookupResult SmallPtrSet instead of vector, following
Douglas suggestions.
- Adds %qN format for printing qualified names to Diagnostic.
- Avoids searching for using-directives in Scopes, which are not
DeclScope, during unqualified name lookup.
llvm-svn: 63739
unqualified-id '('
in C++. The unqualified-id might not refer to any declaration in our
current scope, but declarations by that name might be found via
argument-dependent lookup. We now do so properly.
As part of this change, CXXDependentNameExpr, which was previously
designed to express the unqualified-id in the above constructor within
templates, has become UnresolvedFunctionNameExpr, which does
effectively the same thing but will work for both templates and
non-templates.
Additionally, we cope with all unqualified-ids, since ADL also applies
in cases like
operator+(x, y)
llvm-svn: 63733
a.k.a. Koenig lookup) in C++. Most of the pieces are in place, but for
two:
- In an unqualified call g(x), even if the name does not refer to
anything in the current scope, we can still find functions named
"g" based on ADL. We don't yet have this ability.
- ADL will need updating for friend functions and templates.
llvm-svn: 63692
LookupName et al. Instead, use an enum and a bool to describe its
contents.
Optimized the C/Objective-C path through LookupName, eliminating any
unnecessarily C++isms. Simplify IdentifierResolver::iterator, removing
some code and arguments that are no longer used.
Eliminated LookupDeclInScope/LookupDeclInContext, moving all callers
over to LookupName, LookupQualifiedName, or LookupParsedName, as
appropriate.
All together, I'm seeing a 0.2% speedup on Cocoa.h with PTH and
-disable-free. Plus, we're down to three name-lookup routines.
llvm-svn: 63354
The previous interface was very confusing. This is much more explicit, which will be easier to understand/optimize/convert.
The plan is to eventually deprecate both of these functions. For now, I'm focused on performance.
llvm-svn: 63256
The approach I've taken in this patch is relatively straightforward,
although the code itself is non-trivial. Essentially, as we process
an initializer list we build up a fully-explicit representation of the
initializer list, where each of the subobject initializations occurs
in order. Designators serve to "fill in" subobject initializations in
a non-linear way. The fully-explicit representation makes initializer
lists (both with and without designators) easy to grok for codegen and
later semantic analyses. We keep the syntactic form of the initializer
list linked into the AST for those clients interested in exactly what
the user wrote.
Known limitations:
- Designating a member of a union that isn't the first member may
result in bogus initialization (we warn about this)
- GNU array-range designators are not supported (we warn about this)
llvm-svn: 63242
Even though Sema::LookupDecl() is deprecated, it's still used all over the place. Simplifying the interface will make it easier to understand/optimize/convert.
llvm-svn: 63210
.def file for each library. This means that adding a diagnostic
to sema doesn't require all the other libraries to be rebuilt.
Patch by Anders Johnsen!
llvm-svn: 63111
think this has any significant effects at the moment, but it could
matter if we start constant-folding statement expressions like gcc does.
llvm-svn: 62943
This allows more concise syntax when allocating an object using the ASTContext's allocator.
Convert a few allocations to this operator to for test purposes.
llvm-svn: 62623
When using a BumpPtrAllocator, this reduces malloc overhead from 2.2->1.9% (for Cocoa.h).
At this point, malloc() has dropped the fourth most expensive routine (behind Preprocessor::HandleIdentifier()).
llvm-svn: 62612
that every declaration lives inside a DeclContext.
Moved several things that don't have names but were ScopedDecls (and,
therefore, NamedDecls) to inherit from Decl rather than NamedDecl,
including ObjCImplementationDecl and LinkageSpecDecl. Now, we don't
store empty DeclarationNames for these things, nor do we try to insert
them into DeclContext's lookup structure.
The serialization tests are temporarily disabled. We'll re-enable them
once we've sorted out the remaining ownership/serialiazation issues
between DeclContexts and TranslationUnion, DeclGroups, etc.
llvm-svn: 62562
new DiagnoseIncompleteType. It provides additional information about
struct/class/union/enum types when possible, either by pointing to the
forward declaration of that type or by pointing to the definition (if
we're in the process of defining that type).
Fixes <rdar://problem/6500531>.
llvm-svn: 62521
Douglas Gregor