From 4e2845d3c8072aa49fc4424a65d6f2b84dcda527 Mon Sep 17 00:00:00 2001
From: Artem Dergachev <artem.dergachev@gmail.com>
Date: Fri, 18 Jan 2019 22:52:13 +0000
Subject: [PATCH] [analyzer] Do not try to body-farm Objective-C properties
 with custom accessors.

If a property is defined with a custom getter, we should not behave as if
the getter simply returns an instance variable. We don't support setters,
so they aren't affected.

On top of being the right thing to do, this also fixes a crash on
the newly added test - in which a property and its getter are defined
in two separate categories.

rdar://problem/47051544

Differential Revision: https://reviews.llvm.org/D56823


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@351609 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Analysis/BodyFarm.cpp  |  5 +++++
 test/Analysis/properties.m | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/lib/Analysis/BodyFarm.cpp b/lib/Analysis/BodyFarm.cpp
index 35f0464067..2a682a8ba4 100644
--- a/lib/Analysis/BodyFarm.cpp
+++ b/lib/Analysis/BodyFarm.cpp
@@ -807,6 +807,11 @@ Stmt *BodyFarm::getBody(const ObjCMethodDecl *D) {
 
   D = D->getCanonicalDecl();
 
+  // We should not try to synthesize explicitly redefined accessors.
+  // We do not know for sure how they behave.
+  if (!D->isImplicit())
+    return nullptr;
+
   Optional<Stmt *> &Val = Bodies[D];
   if (Val.hasValue())
     return Val.getValue();
diff --git a/test/Analysis/properties.m b/test/Analysis/properties.m
index 461639f4c2..17b156035a 100644
--- a/test/Analysis/properties.m
+++ b/test/Analysis/properties.m
@@ -1005,3 +1005,38 @@ void testNoCrashWhenAccessPropertyAndThereAreNoDirectBindingsAtAll() {
 
 #endif // non-ARC
 
+@interface ExplicitAccessorInCategory : NSObject
+@property(readonly) int normal;
+- (int)normal;
+@property(readonly) int no_custom_accessor;
+@end
+
+@interface ExplicitAccessorInCategory ()
+@property(readonly) int in_category;
+
+@property(readonly) int still_no_custom_accessor;
+// This is an ordinary method, not a getter.
+- (int)still_no_custom_accessor;
+@end
+
+@interface ExplicitAccessorInCategory ()
+- (int)in_category;
+
+// This is an ordinary method, not a getter.
+- (int)no_custom_accessor;
+@end
+
+@implementation ExplicitAccessorInCategory
+- (void)foo {
+	// Make sure we don't farm bodies for explicit accessors: in particular,
+	// we're not sure that the accessor always returns the same value.
+	clang_analyzer_eval(self.normal == self.normal); // expected-warning{{UNKNOWN}}
+	// Also this used to crash.
+	clang_analyzer_eval(self.in_category == self.in_category); // expected-warning{{UNKNOWN}}
+
+	// When there is no explicit accessor defined (even if it looks like there is),
+	// farm the getter body and see if it does actually always yield the same value.
+	clang_analyzer_eval(self.no_custom_accessor == self.no_custom_accessor); // expected-warning{{TRUE}}
+	clang_analyzer_eval(self.still_no_custom_accessor == self.still_no_custom_accessor); // expected-warning{{TRUE}}
+}
+@end
-- 
2.40.0