Overhaul the AST representation of Objective-C message send
expressions, to improve source-location information, clarify the
actual receiver of the message, and pave the way for proper C++
support. The ObjCMessageExpr node represents four different kinds of
message sends in a single AST node:
1) Send to a object instance described by an expression (e.g., [x method:5])
2) Send to a class described by the class name (e.g., [NSString method:5])
3) Send to a superclass class (e.g, [super method:5] in class method)
4) Send to a superclass instance (e.g., [super method:5] in instance method)
Previously these four cases where tangled together. Now, they have
more distinct representations. Specific changes:
1) Unchanged; the object instance is represented by an Expr*.
2) Previously stored the ObjCInterfaceDecl* referring to the class
receiving the message. Now stores a TypeSourceInfo* so that we know
how the class was spelled. This both maintains typedef information
and opens the door for more complicated C++ types (e.g., dependent
types). There was an alternative, unused representation of these
sends by naming the class via an IdentifierInfo *. In practice, we
either had an ObjCInterfaceDecl *, from which we would get the
IdentifierInfo *, or we fell into the case below...
3) Previously represented by a class message whose IdentifierInfo *
referred to "super". Sema and CodeGen would use isStr("super") to
determine if they had a send to super. Now represented as a
"class super" send, where we have both the location of the "super"
keyword and the ObjCInterfaceDecl* of the superclass we're
targetting (statically).
4) Previously represented by an instance message whose receiver is a
an ObjCSuperExpr, which Sema and CodeGen would check for via
isa<ObjCSuperExpr>(). Now represented as an "instance super" send,
where we have both the location of the "super" keyword and the
ObjCInterfaceDecl* of the superclass we're targetting
(statically). Note that ObjCSuperExpr only has one remaining use in
the AST, which is for "super.prop" references.
The new representation of ObjCMessageExpr is 2 pointers smaller than
the old one, since it combines more storage. It also eliminates a leak
when we loaded message-send expressions from a precompiled header. The
representation also feels much cleaner to me; comments welcome!
This patch attempts to maintain the same semantics we previously had
with Objective-C message sends. In several places, there are massive
changes that boil down to simply replacing a nested-if structure such
as:
if (message has a receiver expression) {
// instance message
if (isa<ObjCSuperExpr>(...)) {
// send to super
} else {
// send to an object
}
} else {
// class message
if (name->isStr("super")) {
// class send to super
} else {
// send to class
}
}
with a switch
switch (E->getReceiverKind()) {
case ObjCMessageExpr::SuperInstance: ...
case ObjCMessageExpr::Instance: ...
case ObjCMessageExpr::SuperClass: ...
case ObjCMessageExpr::Class:...
}
There are quite a few places (particularly in the checkers) where
send-to-super is effectively ignored. I've placed FIXMEs in most of
them, and attempted to address send-to-super in a reasonable way. This
could use some review.
llvm-svn: 101972
diff --git a/clang/lib/Checker/CheckObjCDealloc.cpp b/clang/lib/Checker/CheckObjCDealloc.cpp
index f510de5..c23be87 100644
--- a/clang/lib/Checker/CheckObjCDealloc.cpp
+++ b/clang/lib/Checker/CheckObjCDealloc.cpp
@@ -27,10 +27,14 @@
static bool scan_dealloc(Stmt* S, Selector Dealloc) {
if (ObjCMessageExpr* ME = dyn_cast<ObjCMessageExpr>(S))
- if (ME->getSelector() == Dealloc)
- if (ME->getReceiver())
- if (Expr* Receiver = ME->getReceiver()->IgnoreParenCasts())
- return isa<ObjCSuperExpr>(Receiver);
+ if (ME->getSelector() == Dealloc) {
+ switch (ME->getReceiverKind()) {
+ case ObjCMessageExpr::Instance: return false;
+ case ObjCMessageExpr::SuperInstance: return true;
+ case ObjCMessageExpr::Class: break;
+ case ObjCMessageExpr::SuperClass: break;
+ }
+ }
// Recurse to children.
@@ -50,16 +54,16 @@
// [mMyIvar release]
if (ObjCMessageExpr* ME = dyn_cast<ObjCMessageExpr>(S))
if (ME->getSelector() == Release)
- if (ME->getReceiver())
- if (Expr* Receiver = ME->getReceiver()->IgnoreParenCasts())
+ if (ME->getInstanceReceiver())
+ if (Expr* Receiver = ME->getInstanceReceiver()->IgnoreParenCasts())
if (ObjCIvarRefExpr* E = dyn_cast<ObjCIvarRefExpr>(Receiver))
if (E->getDecl() == ID)
return true;
// [self setMyIvar:nil];
if (ObjCMessageExpr* ME = dyn_cast<ObjCMessageExpr>(S))
- if (ME->getReceiver())
- if (Expr* Receiver = ME->getReceiver()->IgnoreParenCasts())
+ if (ME->getInstanceReceiver())
+ if (Expr* Receiver = ME->getInstanceReceiver()->IgnoreParenCasts())
if (DeclRefExpr* E = dyn_cast<DeclRefExpr>(Receiver))
if (E->getDecl()->getIdentifier() == SelfII)
if (ME->getMethodDecl() == PD->getSetterMethodDecl() &&