Patch by Nikita Zhuk:

The attached patch adds additional checks to -warn-objc-missing-dealloc. It checks that all ivars which are used in implementation of synthesized properties are either

a) released in dealloc if the property has retain" or "copy" attribute OR
b) not released in dealloc if the property has "assign" attribute

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@58363 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/CheckObjCDealloc.cpp b/lib/Analysis/CheckObjCDealloc.cpp
index f6a3fd0112de23f0baa372c8daeaffb3b8e120ce..617e91b5c33d090f1dc5fbb36053597ec7572d13 100644 (file)
--- a/lib/Analysis/CheckObjCDealloc.cpp
+++ b/lib/Analysis/CheckObjCDealloc.cpp
@@ -20,7 +20,7 @@
 #include "clang/AST/Expr.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/Basic/LangOptions.h"
-#include <sstream>
+#include "llvm/Support/raw_ostream.h"
 
 using namespace clang;
 
@@ -42,6 +42,22 @@ static bool scan_dealloc(Stmt* S, Selector Dealloc) {
   return false;
 }
 
+static bool scan_ivar_release(Stmt* S, ObjCIvarDecl* ID, Selector Release ) {  
+  if (ObjCMessageExpr* ME = dyn_cast<ObjCMessageExpr>(S))
+    if (ME->getSelector() == Release)
+      if (Expr* Receiver = ME->getReceiver()->IgnoreParenCasts())
+        if (ObjCIvarRefExpr* E = dyn_cast<ObjCIvarRefExpr>(Receiver))
+          if (E->getDecl() == ID)
+            return true;
+
+  // Recurse to children.
+  for (Stmt::child_iterator I = S->child_begin(), E= S->child_end(); I!=E; ++I)
+    if (*I && scan_ivar_release(*I, ID, Release))
+      return true;
+
+  return false;
+}
+
 void clang::CheckObjCDealloc(ObjCImplementationDecl* D,
                              const LangOptions& LOpts, BugReporter& BR) {
 
@@ -105,7 +121,8 @@ void clang::CheckObjCDealloc(ObjCImplementationDecl* D,
                        ? "missing -dealloc" 
                        : "missing -dealloc (Hybrid MM, non-GC)";
     
-    std::ostringstream os;
+    std::string buf;
+    llvm::raw_string_ostream os(buf);
     os << "Objective-C class '" << D->getName()
        << "' lacks a 'dealloc' instance method";
     
@@ -120,7 +137,8 @@ void clang::CheckObjCDealloc(ObjCImplementationDecl* D,
                        ? "missing [super dealloc]"
                        : "missing [super dealloc] (Hybrid MM, non-GC)";
     
-    std::ostringstream os;
+    std::string buf;
+    llvm::raw_string_ostream os(buf);
     os << "The 'dealloc' instance method in Objective-C class '" << D->getName()
        << "' does not send a 'dealloc' message to its super class"
            " (missing [super dealloc])";
@@ -128,5 +146,66 @@ void clang::CheckObjCDealloc(ObjCImplementationDecl* D,
     BR.EmitBasicReport(name, os.str().c_str(), D->getLocStart());
     return;
   }   
+  
+  // Get the "release" selector.
+  IdentifierInfo* RII = &Ctx.Idents.get("release");
+  Selector RS = Ctx.Selectors.getSelector(0, &RII);  
+  
+  // Scan for missing and extra releases of ivars used by implementations
+  // of synthesized properties
+  for (ObjCImplementationDecl::propimpl_iterator I = D->propimpl_begin(),
+       E = D->propimpl_end(); I!=E; ++I) {
+
+    // We can only check the synthesized properties
+    if((*I)->getPropertyImplementation() != ObjCPropertyImplDecl::Synthesize)
+      continue;
+    
+    ObjCIvarDecl* ID = (*I)->getPropertyIvarDecl();
+    if (!ID)
+      continue;
+    
+    QualType T = ID->getType();
+    if (!Ctx.isObjCObjectPointerType(T)) // Skip non-pointer ivars
+      continue;
+
+    const ObjCPropertyDecl* PD = (*I)->getPropertyDecl();
+    if(!PD)
+      continue;
+    
+    // ivars cannot be set via read-only properties, so we'll skip them
+    if(PD->isReadOnly())
+       continue;
+              
+    // ivar must be released if and only if the kind of setter was not 'assign'
+    bool requiresRelease = PD->getSetterKind() != ObjCPropertyDecl::Assign;
+    if(scan_ivar_release(MD->getBody(), ID, RS) != requiresRelease) {
+      const char *name;
+      const char* category = "Memory (Core Foundation/Objective-C)";
+      
+      std::string buf;
+      llvm::raw_string_ostream os(buf);
+
+      if(requiresRelease) {
+        name = LOpts.getGCMode() == LangOptions::NonGC
+               ? "missing ivar release (leak)"
+               : "missing ivar release (Hybrid MM, non-GC)";
+        
+        os << "The '" << ID->getName()
+           << "' instance variable was retained by a synthesized property but "
+              "wasn't released in 'dealloc'";        
+      } else {
+        name = LOpts.getGCMode() == LangOptions::NonGC
+               ? "extra ivar release (use-after-release)"
+               : "extra ivar release (Hybrid MM, non-GC)";
+        
+        os << "The '" << ID->getName()
+           << "' instance variable was not retained by a synthesized property "
+              "but was released in 'dealloc'";
+      }
+      
+      BR.EmitBasicReport(name, category,
+                         os.str().c_str(), (*I)->getLocation());
+    }
+  }
 }