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9a12919421
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
87 lines
2.8 KiB
C++
87 lines
2.8 KiB
C++
//=- NSAutoreleasePoolChecker.cpp --------------------------------*- C++ -*-==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines a NSAutoreleasePoolChecker, a small checker that warns
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// about subpar uses of NSAutoreleasePool. Note that while the check itself
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// (in it's current form) could be written as a flow-insensitive check, in
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// can be potentially enhanced in the future with flow-sensitive information.
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// It is also a good example of the CheckerVisitor interface.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Checker/BugReporter/BugReporter.h"
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#include "clang/Checker/PathSensitive/GRExprEngine.h"
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#include "clang/Checker/PathSensitive/CheckerVisitor.h"
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#include "BasicObjCFoundationChecks.h"
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#include "clang/AST/DeclObjC.h"
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#include "clang/AST/Decl.h"
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using namespace clang;
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namespace {
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class NSAutoreleasePoolChecker
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: public CheckerVisitor<NSAutoreleasePoolChecker> {
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Selector releaseS;
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public:
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NSAutoreleasePoolChecker(Selector release_s) : releaseS(release_s) {}
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static void *getTag() {
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static int x = 0;
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return &x;
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}
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void PreVisitObjCMessageExpr(CheckerContext &C, const ObjCMessageExpr *ME);
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};
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} // end anonymous namespace
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void clang::RegisterNSAutoreleasePoolChecks(GRExprEngine &Eng) {
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ASTContext &Ctx = Eng.getContext();
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if (Ctx.getLangOptions().getGCMode() != LangOptions::NonGC) {
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Eng.registerCheck(new NSAutoreleasePoolChecker(GetNullarySelector("release",
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Ctx)));
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}
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}
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void
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NSAutoreleasePoolChecker::PreVisitObjCMessageExpr(CheckerContext &C,
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const ObjCMessageExpr *ME) {
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const Expr *receiver = ME->getInstanceReceiver();
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if (!receiver)
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return;
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// FIXME: Enhance with value-tracking information instead of consulting
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// the type of the expression.
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const ObjCObjectPointerType* PT =
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receiver->getType()->getAs<ObjCObjectPointerType>();
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if (!PT)
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return;
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const ObjCInterfaceDecl* OD = PT->getInterfaceDecl();
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if (!OD)
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return;
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if (!OD->getIdentifier()->getName().equals("NSAutoreleasePool"))
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return;
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// Sending 'release' message?
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if (ME->getSelector() != releaseS)
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return;
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SourceRange R = ME->getSourceRange();
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C.getBugReporter().EmitBasicReport("Use -drain instead of -release",
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"API Upgrade (Apple)",
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"Use -drain instead of -release when using NSAutoreleasePool "
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"and garbage collection", ME->getLocStart(), &R, 1);
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}
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