return statements. We perform NRVO only when all of the return
statements in the function return the same variable. Fixes some link
failures in Boost.Interprocess (which is relying on NRVO), and
probably improves performance for some C++ applications.
llvm-svn: 103867
return value optimization. Sema marks return statements with their
NRVO candidates (which may or may not end up using the NRVO), then, at
the end of a function body, computes and marks those variables that
can be allocated into the return slot.
I've checked this locally with some debugging statements (not
committed), but there won't be any tests until CodeGen comes along.
llvm-svn: 103865
"return" statement and mark the corresponding CXXConstructExpr as
elidable. Teach CodeGen that eliding a temporary is different from
eliding an object construction.
This is just a baby step toward NRVO.
llvm-svn: 103849
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
function-parameter checking and splitting it into the normal
ActOn*/Build* pair in Sema. We now use VarDecl to represent the @catch
parameter rather than the ill-fitting ParmVarDecl.
llvm-svn: 102347
statements. Instead of the @try having a single @catch, where all of
the @catch's were chained (using an O(n^2) algorithm nonetheless),
@try just holds an array of its @catch blocks. The resulting AST is
slightly more compact (not important) and better represents the actual
language semantics (good).
llvm-svn: 102221
input and output types when the smaller value isn't mentioned in the
asm string. Extend this support from integers to also allowing
fp values to be mismatched (if not mentioned in the asm string).
llvm-svn: 102188
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
cache of PartialDiagnostic::Storage objects into an allocator within
the ASTContext. This eliminates a significant amount of malloc
traffic, for a 10% performance improvement in -fsyntax-only wall-clock
time with 403.gcc's combine.c.
Also, eliminate the RequireNonAbstractType hack I put in earlier,
which was but a symptom of this larger problem.
Fixes <rdar://problem/7806091>.
llvm-svn: 99849
which has the label map, switch statement stack, etc. Previously, we
had a single set of maps in Sema (for the function) along with a stack
of block scopes. However, this lead to funky behavior with nested
functions, e.g., in the member functions of local classes.
The explicit-stack approach is far cleaner, and we retain a 1-element
cache so that we're not malloc/free'ing every time we enter a
function. Fixes PR6382.
Also, tweaked the unused-variable warning suppression logic to look at
errors within a given Scope rather than within a given function. The
prior code wasn't looking at the right number-of-errors count when
dealing with blocks, since the block's count would be deallocated
before we got to ActOnPopScope. This approach works with nested
blocks/functions, and gives tighter error recovery.
llvm-svn: 97518
larger unsigned value, since this is implementation-defined
behavior. (We previously suppressed this warning when converting from
a signed value to an unsigned value of the same size).
llvm-svn: 97430
variable type, we can (and should) still check for completeness of the
variable's type. Do so, to work around an assertion that shows up in
Boost's shared_ptr.
llvm-svn: 95934
follows (as conservatively as possible) gcc's current behavior: attributes
written on return types that don't apply there are applied to the function
instead, etc. Only parse CC attributes as type attributes, not as decl attributes;
don't accepet noreturn as a decl attribute on ValueDecls, either (it still
needs to apply to other decls, like blocks). Consistently consume CC/noreturn
information throughout codegen; enforce this by removing their default values
in CodeGenTypes::getFunctionInfo().
llvm-svn: 95436
lvalue-to-rvalue conversion adjusts lvalues of qualified, non-class
type to rvalue expressions of the unqualified variant of that
type. For example, given:
const int i;
(void)(i + 17);
the lvalue-to-rvalue conversion for the subexpression "i" will turn it
from an lvalue expression (a DeclRefExpr) with type 'const int' into
an rvalue expression with type 'int'. Both C and C++ mandate this
conversion, and somehow we've slid through without implementing it.
We now have both DefaultFunctionArrayConversion and
DefaultFunctionArrayLvalueConversion, and which gets used depends on
whether we do the lvalue-to-rvalue conversion or not. Generally, we do
the lvalue-to-rvalue conversion, but there are a few notable
exceptions:
- the left-hand side of a '.' operator
- the left-hand side of an assignment
- a C++ throw expression
- a subscript expression that's subscripting a vector
Making this change exposed two issues with blocks:
- we were deducing const-qualified return types of non-class type
from a block return, which doesn't fit well
- we weren't always setting the known return type of a block when it
was provided with the ^return-type syntax
Fixes the current Clang-on-Clang compile failure and PR6076.
llvm-svn: 95167
Change LookupResult to use UnresolvedSet. Also extract UnresolvedSet into its
own header and make it templated over an inline capacity.
llvm-svn: 93959
new InitializationSequence. This fixes some bugs (e.g., PR5808),
changed some diagnostics, and caused more churn than expected. What's
new:
- InitializationSequence now has a "C conversion sequence" category
and step kind, which falls back to
- Changed the diagnostics for returns to always have the result type
of the function first and the type of the expression second.
CheckSingleAssignmentConstraints to peform checking in C.
- Improved ASTs for initialization of return values. The ASTs now
capture all of the temporaries we need to create, but
intentionally do not bind the tempoary that is actually returned,
so that it won't get destroyed twice.
- Make sure to perform an (elidable!) copy of the class object that
is returned from a class.
- Fix copy elision in CodeGen to properly see through the
subexpressions that occur with elidable copies.
- Give "new" its own entity kind; as with return values and thrown
objects, we don't bind the expression so we don't call a
destructor for it.
Note that, with this patch, I've broken returning move-only types in
C++0x. We'll fix it later, when we tackle NRVO.
llvm-svn: 91669
