"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
referenced unless we see one of them defined (or the key function
defined, if it as one) or if we need the vtable for something. Fixes
PR7114.
llvm-svn: 103497
if/switch/while/do/for statements. Previously, we would end up either:
(1) Forgetting to destroy temporaries created in the condition (!),
(2) Destroying the temporaries created in the condition *before*
converting the condition to a boolean value (or, in the case of a
switch statement, to an integral or enumeral value), or
(3) In a for statement, destroying the condition's temporaries at
the end of the increment expression (!).
We now destroy temporaries in conditions at the right times. This
required some tweaking of the Parse/Sema interaction, since the parser
was building full expressions too early in many places.
Fixes PR7067.
llvm-svn: 103187
"bottom-up" when implicit casts and comparisons are inserted, compute them
"top-down" when the full expression is finished. Makes it easier to
coordinate warnings and thus implement -Wconversion for signedness
conversions without double-warning with -Wsign-compare. Also makes it possible
to realize that a signedness conversion is okay because the context is
performing the inverse conversion. Also simplifies some logic that was
trying to calculate the ultimate comparison/result type and getting it wrong.
Also fixes a problem with the C++ explicit casts which are often "implemented"
in the AST with a series of implicit cast expressions.
llvm-svn: 103174
address of an overloaded function (or function template), perform that
resolution prior to determining the implicit conversion
sequence. This resolution is not part of the implicit conversion
sequence itself.
Previously, we would always consider this resolution to be a
function pointer decay, which was a lie: there might be an explicit &
in the expression, in which case decay should not occur. This caused
the CodeGen assertion in PR6973 (where we created a
pointer to a pointer to a function when we should have had a pointer
to a function), but it's likely that there are corner cases of
overload resolution where this would have failed.
Cleaned up the code involved in determining the type that will
produced afer resolving the overloaded function reference, and added
an assertion to make sure the result is correct. Fixes PR6973.
llvm-svn: 102650
by using TypeSourceInfo, cleaning up the representation
somewhat. Teach getTypeOperand() to strip references and
cv-qualifiers, providing the semantic view of the type without
requiring any extra storage (the unmodified type remains within the
TypeSourceInfo). This fixes a bug found by Boost's call_traits test.
Finally, clean up semantic analysis, by splitting the ActOnCXXTypeid
routine into ActOnCXXTypeId (the parser action) and two BuildCXXTypeId
functions, which perform the semantic analysis for typeid(type) and
typeid(expression), respectively. We now perform less work at template
instantiation time (we don't look for std::type_info again) and can
give better diagnostics.
llvm-svn: 102393
(e.g., no typename, enum, class, etc.), e.g., because the context is
one that is known to refer to a type. Patch from Enea Zaffanella!
llvm-svn: 102243
in a throw expression. Use EmitAnyExprToMem to emit the throw expression,
which magically elides the final copy-constructor call (which raises a new
strict-compliance bug, but baby steps). Give __cxa_throw a destructor pointer
if the exception type has a non-trivial destructor.
llvm-svn: 102039
function declaration, since it may end up being changed (e.g.,
"extern" can become "static" if a prior declaration was static). Patch
by Enea Zaffanella and Paolo Bolzoni.
llvm-svn: 101826
TryStaticImplicitCast (for references, class types, and everything
else, respectively) into a single invocation of
InitializationSequence.
One of the paths (for class types) was the only client of
Sema::TryInitializationByConstructor, which I have eliminated. This
also simplified the interface for much of the cast-checking logic,
eliminating yet more code.
I've kept the representation of C++ functional casts with <> 1
arguments the same, despite the fact that I hate it. That fix will
come soon. To satisfy my paranoia, I've bootstrapped + tested Clang
with these changes.
llvm-svn: 101549
the underlying/instantiated decl) through a lot of API, including "intermediate"
MemberExprs required for (e.g.) template instantiation. This is necessary
because of the access semantics of member accesses to using declarations:
only the base class *containing the using decl* need be accessible from the
naming class.
This allows us to complete an access-controlled selfhost, if there are no
recent regressions.
llvm-svn: 99936
This introduces FunctionType::ExtInfo to hold the calling convention and the
noreturn attribute. The next patch will extend it to include the regparm
attribute and fix the bug.
llvm-svn: 99920
expression can be converted to the type of another, only apply the
lvalue-to-rvalue conversion to the type of the expression we're
converting, *not* the array-to-pointer or function-to-pointer
conversions. Fixes PR6595.
llvm-svn: 99652
initialization code. Exposed a bug where we were not marking an
implicit conversion as an lvalue when we were forming a call to a
conversion function whose return type is a reference.
llvm-svn: 99459
entity (if applicable) which was actually looked up. If a candidate was found
via a using declaration, this is the UsingShadowDecl; otherwise, if
the candidate is template specialization, this is the template; otherwise,
this is the function.
The point of this exercise is that "found declarations" are the entities
we do access control for, not their underlying declarations. Broadly speaking,
this patch fixes access control for using declarations.
There is a *lot* of redundant code calling into the overload-resolution APIs;
we really ought to clean that up.
llvm-svn: 98945
non-placement news when selecting the corresponding operator delete; this is
fixed.
Access and ambiguity control for calls to operator new and delete. Also AFAICT
llvm-svn: 98818
Douglas Gregor