[PATCH] D17627: Fix false positives for for-loop-analysis warning

Steven Wu via cfe-commits cfe-commits at lists.llvm.org
Wed Mar 9 12:52:04 PST 2016


steven_wu updated this revision to Diff 50186.
steven_wu added a comment.

Update the patch to address John's feedback. We shouldn't even checking
ObjCSubscript but looking at the Semantics for PseudoObjectExpr only.


http://reviews.llvm.org/D17627

Files:
  lib/Sema/SemaStmt.cpp
  test/SemaObjC/warn-loop-analysis.m

Index: test/SemaObjC/warn-loop-analysis.m
===================================================================
--- /dev/null
+++ test/SemaObjC/warn-loop-analysis.m
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -fsyntax-only -Wloop-analysis -verify %s
+// expected-no-diagnostics
+
+ at interface MyArray
+- (id)objectAtIndexedSubscript:(unsigned int)idx;
+ at end
+
+// Do not warn on objc classes has objectAtIndexedSubscript method.
+MyArray *test;
+void foo()
+{
+  unsigned int i;
+  for (i = 42; i > 0;) // No warnings here
+    (void)test[--i];
+}
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp
+++ lib/Sema/SemaStmt.cpp
@@ -1440,6 +1440,19 @@
           FoundDecl = true;
     }
 
+    void VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
+      // Only need to visit the semantics for POE.
+      // SyntaticForm doesn't really use the Decal.
+      for (auto *S : POE->semantics()) {
+        if (auto *OVE = dyn_cast<OpaqueValueExpr>(S)) {
+          // Look pass OVE for Decl.
+          if (Expr *E = OVE->getSourceExpr())
+            Visit(E);
+        } else
+          Visit(S);
+      }
+    }
+
     bool FoundDeclInUse() { return FoundDecl; }
 
   };  // end class DeclMatcher


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D17627.50186.patch
Type: text/x-patch
Size: 1255 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20160309/44e71b6b/attachment.bin>


More information about the cfe-commits mailing list