"used" (e.g., we will refer to the vtable in the generated code) and
when they are defined (i.e., because we've seen the key function
definition). Previously, we were effectively tracking "potential
definitions" rather than uses, so we were a bit too eager about emitting
vtables for classes without key functions.
The new scheme:
- For every use of a vtable, Sema calls MarkVTableUsed() to indicate
the use. For example, this occurs when calling a virtual member
function of the class, defining a constructor of that class type,
dynamic_cast'ing from that type to a derived class, casting
to/through a virtual base class, etc.
- For every definition of a vtable, Sema calls MarkVTableUsed() to
indicate the definition. This happens at the end of the translation
unit for classes whose key function has been defined (so we can
delay computation of the key function; see PR6564), and will also
occur with explicit template instantiation definitions.
- For every vtable defined/used, we mark all of the virtual member
functions of that vtable as defined/used, unless we know that the key
function is in another translation unit. This instantiates virtual
member functions when needed.
- At the end of the translation unit, Sema tells CodeGen (via the
ASTConsumer) which vtables must be defined (CodeGen will define
them) and which may be used (for which CodeGen will define the
vtables lazily).
From a language perspective, both the old and the new schemes are
permissible: we're allowed to instantiate virtual member functions
whenever we want per the standard. However, all other C++ compilers
were more lazy than we were, and our eagerness was both a performance
issue (we instantiated too much) and a portability problem (we broke
Boost test cases, which now pass).
Notes:
(1) There's a ton of churn in the tests, because the order in which
vtables get emitted to IR has changed. I've tried to isolate some of
the larger tests from these issues.
(2) Some diagnostics related to
implicitly-instantiated/implicitly-defined virtual member functions
have moved to the point of first use/definition. It's better this
way.
(3) I could use a review of the places where we MarkVTableUsed, to
see if I missed any place where the language effectively requires a
vtable.
Fixes PR7114 and PR6564.
llvm-svn: 103718
tentative definitions off to the ASTConsumer at the end of the
translation unit.
Eliminate CodeGen's internal tracking of tentative definitions, and
instead hook into ASTConsumer::CompleteTentativeDefinition. Also,
tweak the definition-deferal logic for C++, where there are no
tentative definitions.
Fixes <rdar://problem/6808352>, and will make it much easier for
precompiled headers to cope with tentative definitions in the future.
llvm-svn: 69681
productions (except the already broken ObjC cases like @class X,Y;) in
the parser that can produce more than one Decl return a DeclGroup instead
of a Decl, etc.
This allows elimination of the Decl::NextDeclarator field, and exposes
various clients that should look at all decls in a group, but which were
only looking at one (such as the dumper, printer, etc). These have been
fixed.
Still TODO:
1) there are some FIXME's in the code about potentially using
DeclGroup for better location info.
2) ParseObjCAtDirectives should return a DeclGroup due to @class etc.
3) I'm not sure what is going on with StmtIterator.cpp, or if it can
be radically simplified now.
4) I put a truly horrible hack in ParseTemplate.cpp.
I plan to bring up #3/4 on the mailing list, but don't plan to tackle
#1/2 in the short term.
llvm-svn: 68002
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
- Add CodeGenModule::EmitTopLevelDecl which uses switch on kind
instead of ugly & slow dyn_cast chains.
- Drop some simple forwarding methods into the ObjC runtime.
- Privatize appropriate methods.
llvm-svn: 54827
ObjCProtocolDecl directly.
Implement CodeGen support for forward protocol decls (no-ops are so
nice to implement).
Also moved CGObjCRuntime.h out of CodeGenModule.h
llvm-svn: 54709
- Kill unnecessary #includes in .cpp files. This is an automatic
sweep so some things removed are actually used, but happen to be
included by a previous header. I tried to get rid of the obvious
examples and this was the easiest way to trim the #includes in one
fell swoop.
- We now return to regularly scheduled development.
llvm-svn: 54632
- No (intended) functionality change.
- Primary purpose is to clearly separate (lazy) construction of
globals that are a forward declaration or tentative definition from
those that are the final definition.
- Lazy construction is now encapsulated in
GetAddrOf{Function,GlobalVar} while final definitions are
constructed in EmitGlobal{Function,Var}Definition.
- External interface for dealing with globals is now limited to
EmitGlobal and GetAddrOf{Function,GlobalVar}.
- Also updated helper functions dealing with statics, annotations,
and ctors to be private.
llvm-svn: 54179
This is a fairly mechanical/large change. As a result, I avoided making any changes/simplifications that weren't directly related. I did break two Analysis tests. I also have a couple FIXME's in UninitializedValues.cpp. Ted, can you take a look? If the bug isn't obvious, I am happy to dig in and fix it (since I broke it).
llvm-svn: 49748
lib dir and move all the libraries into it. This follows the main
llvm tree, and allows the libraries to be built in parallel. The
top level now enforces that all the libs are built before Driver,
but we don't care what order the libs are built in. This speeds
up parallel builds, particularly incremental ones.
llvm-svn: 48402
Douglas Gregor