[PATCH] D31029: [analyzer] Fix logical not for pointers with different bit width

[Daniel Marjamäki via Phabricator via cfe-commits]

danielmarjamaki created this revision.

The Static Analyzer assumed that all pointers had the same bit width. Now pass the type to the 'makeNull' method, to construct a null
pointer of the appropiate bit width.

Example code that does not work well:

  int main(void) {
    __cm void *cm_p = 0;
    if (cm_p == 0)
      (void)cm_p;
  }

Unfortunately there is no proper testcase here. The problem is seen with a custom target.


Repository:
  rL LLVM

https://reviews.llvm.org/D31029

Files:
  include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
  include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
  lib/StaticAnalyzer/Core/ExprEngineC.cpp


Index: lib/StaticAnalyzer/Core/ExprEngineC.cpp
===================================================================
--- lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -980,10 +980,9 @@
           //    transfer functions as "0 == E".
           SVal Result;
           if (Optional<Loc> LV = V.getAs<Loc>()) {
-            Loc X = svalBuilder.makeNull();
+            Loc X = svalBuilder.makeNullWithType(Ex->getType());
             Result = evalBinOp(state, BO_EQ, *LV, X, U->getType());
-          }
-          else if (Ex->getType()->isFloatingType()) {
+          } else if (Ex->getType()->isFloatingType()) {
             // FIXME: handle floating point types.
             Result = UnknownVal();
           } else {
Index: include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
===================================================================
--- include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
+++ include/clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h
@@ -310,10 +310,14 @@
     return nonloc::ConcreteInt(BasicVals.getTruthValue(b));
   }
 
-  Loc makeNull() {
-    return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth());
+  // Pass type to accomodate for different pointer bit-witdths of different
+  // address spaces.
+  Loc makeNullWithType(QualType type) {
+    return loc::ConcreteInt(BasicVals.getZeroWithTypeSize(type));
   }
 
+  Loc makeNull() { return loc::ConcreteInt(BasicVals.getZeroWithPtrWidth()); }
+
   Loc makeLoc(SymbolRef sym) {
     return loc::MemRegionVal(MemMgr.getSymbolicRegion(sym));
   }
Index: include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
===================================================================
--- include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
+++ include/clang/StaticAnalyzer/Core/PathSensitive/BasicValueFactory.h
@@ -176,6 +176,11 @@
     return getValue(X);
   }
 
+  inline const llvm::APSInt &getZeroWithTypeSize(QualType T,
+                                                 bool isUnsigned = true) {
+    return getValue(0, Ctx.getTypeSize(T), isUnsigned);
+  }
+
   inline const llvm::APSInt& getZeroWithPtrWidth(bool isUnsigned = true) {
     return getValue(0, Ctx.getTypeSize(Ctx.VoidPtrTy), isUnsigned);
   }


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