protocol, record the definition pointer in the canonical declaration
for that entity, and then propagate that definition pointer from the
canonical declaration to all other deserialized declarations. This
approach works well even when deserializing declarations that didn't
know about the original definition, which can occur with modules.
A nice bonus from this definition-deserialization approach is that we
no longer need update records when a definition is added, because the
redeclaration chains ensure that the if any declaration is loaded, the
definition will also get loaded.
llvm-svn: 148223
is important because it's fairly common for headers (especially system
headers) to want to provide only those typedefs needed for that
particular header, based on some guard macro, e.g.,
#ifndef _SIZE_T
#define _SIZE_T
typedef long size_t;
#endif
which is repeated in a number of headers. The guard macro protects
against duplicate definitions. However, this means that only the first
occurrence of this pattern actually defines size_t, so the submodule
corresponding to this header has the only visible definition. If a
user then imports a different submodule from the same module, size_t
will be known but not visible, and therefore cannot be used.
By allowing redefinition of typedefs, each header that wants to define
size_t can do so independently, so it will be available in the
corresponding submodules.
llvm-svn: 147775
to see hidden declarations because every tag lookup is effectively a
redeclaration lookup. For example, image that
struct foo;
is declared in a submodule that is known but hasn't been imported. If
someone later writes
struct foo *foo_p;
then "struct foo" is either a reference or a redeclaration. To keep
the redeclaration chains sound, we treat it like a redeclaration for
name-lookup purposes.
llvm-svn: 147588
different modules. This implementation is a first approximation of
what we want, using only the function type to determine
equivalence. Later, we'll want to deal with some of the more subtle
issues, including:
- C allows a prototyped declaration and a non-prototyped declaration
to be merged, which we should support
- We may want to ignore the return type when merging, then
complain if the return types differ. Or, we may want to leave it
as it us, so that we only complain if overload resolution
eventually fails.
- C++ non-static member functions need to consider cv-qualifiers
and ref-qualifiers.
- Function templates need to consider the template parameters and
return type.
- Function template specializations will have special rules.
- We can now (accidentally!) end up overloading in C, even without
the "overloadable" attribute, and will need to detect this at some
point.
The actual detection of "is this an overload?" is implemented by
Sema::IsOverload(), which will need to be moved into the AST library
for re-use here. That will be a future refactor.
llvm-svn: 147534
the AST reader doesn't actually perform a merge, because name lookup
knows how to merge identical typedefs together.
As part of this, teach C/Objective-C name lookup to return multiple
results in all cases, rather than first digging through the attributes
to see if the value is overloadable. This way, we'll catch ambiguous
lookups in C/Objective-C.
llvm-svn: 147498
that if two modules A and B both contain a declaration of a tag such
as
struct X;
and those two modules are unrelated, the two declarations of X will be
merged into a single redeclaration chain.
llvm-svn: 147488
set of (previously-canonical) declaration IDs to the module file, so
that future AST reader instances that load the module know which
declarations are merged. This is important in the fairly tricky case
where a declaration of an entity, e.g.,
@class X;
occurs before the import of a module that also declares that
entity. We merge the declarations, and record the fact that the
declaration of X loaded from the module was merged into the (now
canonical) declaration of X that we parsed.
llvm-svn: 147181
declaration of that same class that either came from some other module
or occurred in the translation unit loading the module. In this case,
we need to merge the two redeclaration chains immediately so that all
such declarations have the same canonical declaration in the resulting
AST (even though they don't in the module files we've imported).
Focusing on Objective-C classes until I'm happy with the design, then
I'll both (1) extend this notion to other kinds of declarations, and
(2) optimize away this extra checking when we're not dealing with
modules. For now, doing this checking for PCH files/preambles gives us
better testing coverage.
llvm-svn: 147123
visibility restrictions. This ensures that all declarations of the
same entity end up in the same redeclaration chain, even if some of
those declarations aren't visible. While this may seem unfortunate to
some---why can't two C modules have different functions named
'f'?---it's an acknowedgment that a module does not introduce a new
"namespace" of names.
As part of this, stop merging the 'module-private' bit from previous
declarations to later declarations, because we want each declaration
in a module to stand on its own because this can effect, for example,
submodule visibility.
Note that this notion of names that are invisible to normal name
lookup but are available for redeclaration lookups is how we should
implement friend declarations and extern declarations within local
function scopes. I'm not tackling that problem now.
llvm-svn: 146980
with a definition pointer (e.g., C++ and Objective-C classes), zip
through the redeclaration chain to make sure that all of the
declarations point to the definition data.
As part of this, realized again why the first redeclaration of an
entity in a file is important, and brought back that idea.
llvm-svn: 146886
redeclaration templates (RedeclarableTemplateDecl), similarly to the
way (de-)serialization is implemented for Redeclarable<T>. In the
process, found a simpler formulation for handling redeclaration
chains and implemented that in both places.
The new test establishes that we're building the redeclaration chains
properly. However, the FIXME indicates where we're tickling a
different bug that has to do with us not setting the DefinitionData
pointer properly in redeclarations that we detected after the
definition itself was deserialized. The (separable) fix for that bug
is forthcoming.
llvm-svn: 146883
imported modules that don't introduce any new entities of a particular
kind. Allow these entries to be replaced with entries for another
loaded module.
In the included test case, selectors exhibit this behavior.
llvm-svn: 146870
which there are no redeclarations. This reduced by size of the PCH
file for Cocoa.h by ~650k: ~536k of that was in the new
LOCAL_REDECLARATIONS table, which went from a ridiculous 540k down to
an acceptable 3.5k, while the rest was due to the more compact
abbreviated representation of redeclarable declaration kinds (which no
longer need to store the 'first' declaration ID).
llvm-svn: 146869
chains. The previous implementation relied heavily on the declaration
chain being stored as a (circular) linked list on disk, as it is in
memory. However, when deserializing from multiple modules, the
different chains could get mixed up, leading to broken declaration chains.
The new solution keeps track of the first and last declarations in the
chain for each module file. When we load a declaration, we search all
of the module files for redeclarations of that declaration, then
splice together all of the lists into a coherent whole (along with any
redeclarations that were actually parsed).
As a drive-by fix, (de-)serialize the redeclaration chains of
TypedefNameDecls, which had somehow gotten missed previously. Add a
test of this serialization.
This new scheme creates a redeclaration table that is fairly large in
the PCH file (on the order of 400k for Cocoa.h's 12MB PCH file). The
table is mmap'd in and searched via a binary search, but it's still
quite large. A future tweak will eliminate entries for declarations
that have no redeclarations anywhere, and should
drastically reduce the size of this table.
llvm-svn: 146841
Ted Kremenek