r333471 - Check pointer null-ness before dereferencing it.

[Richard Trieu via cfe-commits]

Author: rtrieu
Date: Tue May 29 15:43:00 2018
New Revision: 333471

URL: http://llvm.org/viewvc/llvm-project?rev=333471&view=rev
Log:
Check pointer null-ness before dereferencing it.

-Warc-repeated-use-of-weak may trigger a segmentation fault when the Decl
being checked is outside of a function scope, leaving the current function
info pointer null.  This adds a check before using the function info.

Modified:
    cfe/trunk/lib/Sema/SemaDecl.cpp
    cfe/trunk/test/SemaObjC/arc-repeated-weak.mm

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=333471&r1=333470&r2=333471&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Tue May 29 15:43:00 2018
@@ -10799,11 +10799,12 @@ void Sema::AddInitializerToDecl(Decl *Re
     // we do not warn to warn spuriously when 'x' and 'y' are on separate
     // paths through the function. This should be revisited if
     // -Wrepeated-use-of-weak is made flow-sensitive.
-    if ((VDecl->getType().getObjCLifetime() == Qualifiers::OCL_Strong ||
-         VDecl->getType().isNonWeakInMRRWithObjCWeak(Context)) &&
-        !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak,
-                         Init->getLocStart()))
-      getCurFunction()->markSafeWeakUse(Init);
+    if (FunctionScopeInfo *FSI = getCurFunction())
+      if ((VDecl->getType().getObjCLifetime() == Qualifiers::OCL_Strong ||
+           VDecl->getType().isNonWeakInMRRWithObjCWeak(Context)) &&
+          !Diags.isIgnored(diag::warn_arc_repeated_use_of_weak,
+                           Init->getLocStart()))
+        FSI->markSafeWeakUse(Init);
   }
 
   // The initialization is usually a full-expression.

Modified: cfe/trunk/test/SemaObjC/arc-repeated-weak.mm
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/arc-repeated-weak.mm?rev=333471&r1=333470&r2=333471&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjC/arc-repeated-weak.mm (original)
+++ cfe/trunk/test/SemaObjC/arc-repeated-weak.mm Tue May 29 15:43:00 2018
@@ -479,3 +479,6 @@ void foo1() {
 // expected-error at -2{{cast of 'E' to 'INTFPtrTy' (aka 'INTF *') is disallowed with ARC}}
 #endif
 }
+
+ at class NSString;
+static NSString* const kGlobal = @"";