This change effects both RecordDecls and CXXRecordDecls, but does not effect EnumDecls (yet).
The motivation of this patch is as follows:
- Capture more source information, necessary for refactoring/rewriting clients.
- Pave the way to resolve ownership issues with RecordDecls with the forthcoming
addition of DeclGroups.
Current caveats:
- Until DeclGroups are in place, we will leak RecordDecls not explicitly
referenced by the AST. For example:
typedef struct { ... } x;
The RecordDecl for the struct will be leaked because the TypedefDecl doesn't
refer to it. This will be solved with DeclGroups.
- This patch also (temporarily) breaks CodeGen. More below.
High-level changes:
- As before, TagType still refers to a TagDecl, but it doesn't own it. When
a struct/union/class is first referenced, a RecordType and RecordDecl are
created for it, and the RecordType refers to that RecordDecl. Later, if
a new RecordDecl is created, the pointer to a RecordDecl in RecordType is
updated to point to the RecordDecl that defines the struct/union/class.
- TagDecl and RecordDecl now how a method 'getDefinition()' to return the
TagDecl*/RecordDecl* that refers to the TagDecl* that defines a particular
enum/struct/class/union. This is useful from going from a RecordDecl* that
defines a forward declaration to the RecordDecl* that provides the actual
definition. Note that this also works for EnumDecls, except that in this case
there is no distinction between forward declarations and definitions (yet).
- Clients should no longer assume that 'isDefinition()' returns true from a
RecordDecl if the corresponding struct/union/class has been defined.
isDefinition() only returns true if a particular RecordDecl is the defining
Decl. Use 'getDefinition()' instead to determine if a struct has been defined.
- The main changes to Sema happen in ActOnTag. To make the changes more
incremental, I split off the processing of enums and structs et al into two
code paths. Enums use the original code path (which is in ActOnTag) and
structs use the ActOnTagStruct. Eventually the two code paths will be merged,
but the idea was to preserve the original logic both for comparison and not to
change the logic for both enums and structs all at once.
- There is NO CHAINING of RecordDecls for the same RecordType. All RecordDecls
that correspond to the same type simply have a pointer to that type. If we
need to figure out what are all the RecordDecls for a given type we can build
a backmap.
- The diff in CXXRecordDecl.[cpp,h] is actually very small; it just mimics the
changes to RecordDecl. For some reason 'svn' marks the entire file as changed.
Why is CodeGen broken:
- Codegen assumes that there is an equivalence between RecordDecl* and
RecordType*. This was true before because we only created one RecordDecl* for
a given RecordType*, but it is no longer true. I believe this shouldn't be too
hard to change, but the patch was big enough as it is.
I have tested this patch on both the clang test suite, and by running the static analyzer over Postgresql and a large Apple-internal project (mix of Objective-C and C).
llvm-svn: 55839
The motivation behind this change is that chaining the RecordDecls is simply unnecessary. Once we create multiple RecordDecls for the same struct/union/class, clients that care about all the declarations of the same struct can build a back map by seeing which Decls refer to the same RecordType.
llvm-svn: 55821
- Change constructor and create methods to accept a CXXRecordDecl* (RecordDecl*)
instead of a ScopedDecl* for PrevDecl. This causes the type checking
to be more tight and doesn't break any code.
RecordDecl:
- Don't use the NextDeclarator field in ScopedDecl to represent the previous
declaration. This is a conflated use of the NextDeclarator field, which will
be removed anyway when DeclGroups are fully implemented.
- Instead, represent (a soon to be implemented) chain of RecordDecls using a
NextDecl field. The last RecordDecl in the chain is always the 'defining'
RecordDecl that owns the FieldDecls. The other RecordDecls in the chain
are forward declarations.
llvm-svn: 55640
Argyrios Kyrtzidis