[cfe-commits] r93017 - in /cfe/trunk: lib/Analysis/GRExprEngine.cpp test/Analysis/misc-ps-ranges.m

[Ted Kremenek]

Author: kremenek
Date: Fri Jan  8 12:54:04 2010
New Revision: 93017

URL: http://llvm.org/viewvc/llvm-project?rev=93017&view=rev
Log:
Fix handling in GRExprEngine of 'default' branch in switch statements
when the default case is winnowed down to be infeasible.  When all
cases were ruled out (and the analysis state for the default case
would be infeasible) we would still consider the default case
possible.  This fixes PR 5969.

Modified:
    cfe/trunk/lib/Analysis/GRExprEngine.cpp
    cfe/trunk/test/Analysis/misc-ps-ranges.m

Modified: cfe/trunk/lib/Analysis/GRExprEngine.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/GRExprEngine.cpp?rev=93017&r1=93016&r2=93017&view=diff

==============================================================================
--- cfe/trunk/lib/Analysis/GRExprEngine.cpp (original)
+++ cfe/trunk/lib/Analysis/GRExprEngine.cpp Fri Jan  8 12:54:04 2010
@@ -1221,7 +1221,8 @@
 
     do {
       nonloc::ConcreteInt CaseVal(getBasicVals().getValue(V1.Val.getInt()));
-      DefinedOrUnknownSVal Res = SVator.EvalEQ(DefaultSt, CondV, CaseVal);
+      DefinedOrUnknownSVal Res = SVator.EvalEQ(DefaultSt ? DefaultSt : state,
+                                               CondV, CaseVal);
             
       // Now "assume" that the case matches.
       if (const GRState* stateNew = state->Assume(Res, true)) {
@@ -1236,11 +1237,17 @@
 
       // Now "assume" that the case doesn't match.  Add this state
       // to the default state (if it is feasible).
-      if (const GRState *stateNew = DefaultSt->Assume(Res, false)) {
-        defaultIsFeasible = true;
-        DefaultSt = stateNew;
+      if (DefaultSt) {
+        if (const GRState *stateNew = DefaultSt->Assume(Res, false)) {
+          defaultIsFeasible = true;
+          DefaultSt = stateNew;
+        }
+        else {
+          defaultIsFeasible = false;
+          DefaultSt = NULL;
+        }
       }
-
+        
       // Concretize the next value in the range.
       if (V1.Val.getInt() == V2.Val.getInt())
         break;

Modified: cfe/trunk/test/Analysis/misc-ps-ranges.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/misc-ps-ranges.m?rev=93017&r1=93016&r2=93017&view=diff

==============================================================================
--- cfe/trunk/test/Analysis/misc-ps-ranges.m (original)
+++ cfe/trunk/test/Analysis/misc-ps-ranges.m Fri Jan  8 12:54:04 2010
@@ -21,3 +21,40 @@
 
   return *p; // no-warning
 }
+
+// PR 5969: the comparison of argc < 3 || argc > 4 should constraint the switch
+//  statement from having the 'default' branch taken.  This previously reported a false
+//  positive with the use of 'v'.
+
+int pr5969(int argc, char *argv[]) {
+
+  int v;
+
+  if ((argc < 3) || (argc > 4)) return 0;
+
+  switch(argc) {
+    case 3:
+      v = 33;
+      break;
+    case 4:
+      v = 44;
+      break;
+  }
+
+  return v; // no-warning
+}
+
+int pr5969_positive(int argc, char *argv[]) {
+
+  int v;
+
+  if ((argc < 3) || (argc > 4)) return 0;
+
+  switch(argc) {
+    case 3:
+      v = 33;
+      break;
+  }
+
+  return v; // expected-warning{{Undefined or garbage value returned to caller}}
+}