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.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101972 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/BasicObjCFoundationChecks.cpp b/lib/Checker/BasicObjCFoundationChecks.cpp
index 810d0fb..e7275ca 100644
--- a/lib/Checker/BasicObjCFoundationChecks.cpp
+++ b/lib/Checker/BasicObjCFoundationChecks.cpp
@@ -31,13 +31,22 @@
using namespace clang;
static const ObjCInterfaceType* GetReceiverType(const ObjCMessageExpr* ME) {
- const Expr* Receiver = ME->getReceiver();
+ QualType T;
+ switch (ME->getReceiverKind()) {
+ case ObjCMessageExpr::Instance:
+ T = ME->getInstanceReceiver()->getType();
+ break;
- if (!Receiver)
- return NULL;
+ case ObjCMessageExpr::SuperInstance:
+ T = ME->getSuperType();
+ break;
- if (const ObjCObjectPointerType *PT =
- Receiver->getType()->getAs<ObjCObjectPointerType>())
+ case ObjCMessageExpr::Class:
+ case ObjCMessageExpr::SuperClass:
+ return 0;
+ }
+
+ if (const ObjCObjectPointerType *PT = T->getAs<ObjCObjectPointerType>())
return PT->getInterfaceType();
return NULL;
@@ -509,11 +518,21 @@
void ClassReleaseChecker::PreVisitObjCMessageExpr(CheckerContext &C,
const ObjCMessageExpr *ME) {
-
- const IdentifierInfo *ClsName = ME->getClassName();
- if (!ClsName)
+ ObjCInterfaceDecl *Class = 0;
+ switch (ME->getReceiverKind()) {
+ case ObjCMessageExpr::Class:
+ Class = ME->getClassReceiver()->getAs<ObjCInterfaceType>()->getDecl();
+ break;
+
+ case ObjCMessageExpr::SuperClass:
+ Class = ME->getSuperType()->getAs<ObjCInterfaceType>()->getDecl();
+ break;
+
+ case ObjCMessageExpr::Instance:
+ case ObjCMessageExpr::SuperInstance:
return;
-
+ }
+
Selector S = ME->getSelector();
if (!(S == releaseS || S == retainS || S == autoreleaseS || S == drainS))
return;
@@ -531,7 +550,7 @@
llvm::raw_svector_ostream os(buf);
os << "The '" << S.getAsString() << "' message should be sent to instances "
- "of class '" << ClsName->getName()
+ "of class '" << Class->getName()
<< "' and not the class directly";
RangedBugReport *report = new RangedBugReport(*BT, os.str(), N);