[Sema]. Warn when logical expression is a pointer

which evaluates to true. rdar://18716393.
Reviewed by Richard Trieu

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@222009 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index a7d8a241acc29810fd21810de8753e7d426a7e99..905f60d2a07a68fb2bd4793756a1d44730ca9f18 100644 (file)
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -2771,6 +2771,8 @@ public:
                                       const AttributeList *AttrList);
 
   void checkUnusedDeclAttributes(Declarator &D);
+    
+  void CheckBoolLikeConversion(Expr *E, SourceLocation CC);
 
   /// Determine if type T is a valid subject for a nonnull and similar
   /// attributes. By default, we look through references (the behavior used by

diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index ea4f3476b6ce85e73698ef0ac50404850d3d6cc1..31b643f13858d23439b2039313353bd8c80bec5b 100644 (file)
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -6559,6 +6559,13 @@ void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
       continue;
     AnalyzeImplicitConversions(S, ChildExpr, CC);
   }
+  if (BO && BO->isLogicalOp()) {
+    S.CheckBoolLikeConversion(BO->getLHS(), BO->getLHS()->getExprLoc());
+    S.CheckBoolLikeConversion(BO->getRHS(), BO->getRHS()->getExprLoc());
+  }
+  if (const UnaryOperator *U = dyn_cast<UnaryOperator>(E))
+    if (U->getOpcode() == UO_LNot)
+      S.CheckBoolLikeConversion(U->getSubExpr(), CC);
 }
 
 } // end anonymous namespace
@@ -6617,6 +6624,18 @@ static bool IsInAnyMacroBody(const SourceManager &SM, SourceLocation Loc) {
   return false;
 }
 
+/// CheckBoolLikeConversion - Check conversion of given expression to boolean.
+/// Input argument E is a logical expression.
+static void CheckBoolLikeConversion(Sema &S, Expr *E, SourceLocation CC) {
+  if (S.getLangOpts().Bool)
+    return;
+  CheckImplicitConversion(S, E->IgnoreParenImpCasts(), S.Context.BoolTy, CC);
+}
+
+void Sema::CheckBoolLikeConversion(Expr *E, SourceLocation CC) {
+  ::CheckBoolLikeConversion(*this, E, CC);
+}
+
 /// \brief Diagnose pointers that are always non-null.
 /// \param E the expression containing the pointer
 /// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index de080117b49cb78a698c876225891ad1c500eda6..dde3f3764f1b0a1857b86ce69d9a18fcf0ed7bfc 100644 (file)
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -12984,6 +12984,7 @@ ExprResult Sema::CheckBooleanCondition(Expr *E, SourceLocation Loc) {
         << T << E->getSourceRange();
       return ExprError();
     }
+    CheckBoolLikeConversion(E, Loc);
   }
 
   return E;

diff --git a/test/Analysis/NSContainers.m b/test/Analysis/NSContainers.m
index 4b3492645682ede6e30e8b8c25cb1ce57d53df06..402ce2c90a1795aa155817363fd3e9d179b4b2f6 100644 (file)
--- a/test/Analysis/NSContainers.m
+++ b/test/Analysis/NSContainers.m
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -analyze -analyzer-checker=core,osx.cocoa.NonNilReturnValue,osx.cocoa.NilArg,osx.cocoa.Loops,debug.ExprInspection -verify -Wno-objc-root-class %s
+// RUN: %clang_cc1  -Wno-objc-literal-conversion -analyze -analyzer-checker=core,osx.cocoa.NonNilReturnValue,osx.cocoa.NilArg,osx.cocoa.Loops,debug.ExprInspection -verify -Wno-objc-root-class %s
 
 void clang_analyzer_eval(int);
 

diff --git a/test/Analysis/logical-ops.c b/test/Analysis/logical-ops.c
index afaa2f1077807767b7a115639e68cac285c24151..0b63bc9ec835b17f515999a51fca9e1cdff2849d 100644 (file)
--- a/test/Analysis/logical-ops.c
+++ b/test/Analysis/logical-ops.c
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -analyze -analyzer-checker=core,debug.ExprInspection -verify %s
+// RUN: %clang_cc1 -Wno-pointer-bool-conversion -analyze -analyzer-checker=core,debug.ExprInspection -verify %s
 
 void clang_analyzer_eval(int);
 

diff --git a/test/Analysis/objc-boxing.m b/test/Analysis/objc-boxing.m
index c23192e17e5d687619c5c2518aba0cafdb1657db..73386f463bc81282b9b913561817dbc482c76200 100644 (file)
--- a/test/Analysis/objc-boxing.m
+++ b/test/Analysis/objc-boxing.m
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -analyze -analyzer-checker=core,unix.Malloc,osx.cocoa.NonNilReturnValue,debug.ExprInspection -analyzer-store=region -verify %s
+// RUN: %clang_cc1 -Wno-objc-literal-conversion -analyze -analyzer-checker=core,unix.Malloc,osx.cocoa.NonNilReturnValue,debug.ExprInspection -analyzer-store=region -verify %s
 
 void clang_analyzer_eval(int);
 

diff --git a/test/Sema/exprs.c b/test/Sema/exprs.c
index 2fb17e4880c645edbc9c6243eacc67ea062ba7f1..17b1aa2851b067cd47c7fbae7a68ff7dda4cf216 100644 (file)
--- a/test/Sema/exprs.c
+++ b/test/Sema/exprs.c
@@ -244,6 +244,10 @@ void test22() {
   if ("help")
     (void) 0;
 
-  if (test22)
+  if (test22) // expected-warning {{address of function 'test22' will always evaluate to 'true'}} \
+             // expected-note {{prefix with the address-of operator to silence this warning}}
+    (void) 0;
+
+  if (&test22)
     (void) 0;
 }

diff --git a/test/Sema/warn-tautological-compare.c b/test/Sema/warn-tautological-compare.c
new file mode 100644 (file)
index 0000000..2856edd
--- /dev/null
+++ b/test/Sema/warn-tautological-compare.c
@@ -0,0 +1,80 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin -fsyntax-only -verify  %s
+// rdar://18716393
+
+extern int a[] __attribute__((weak));
+int b[] = {8,13,21};
+struct {
+  int x[10];
+} c;
+const char str[] = "text";
+
+void ignore() {
+  if (!a) {}
+}
+void test() {
+  if (!b) {} // expected-warning {{address of array 'b' will always evaluate to 'true'}}
+  if (b == 0) {} // expected-warning {{comparison of array 'b' equal to a null pointer is always false}}
+  if (!c.x) {} // expected-warning {{address of array 'c.x' will always evaluate to 'true'}}
+  if (c.x == 0) {} // expected-warning {{comparison of array 'c.x' equal to a null pointer is always false}}
+  if (!str) {} // expected-warning {{address of array 'str' will always evaluate to 'true'}}
+  if (0 == str) {} // expected-warning {{comparison of array 'str' equal to a null pointer is always false}}
+}
+
+int array[2];
+int test1()
+{
+  if (!array) { // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+    return array[0];
+  } else if (array != 0) { // expected-warning {{comparison of array 'array' not equal to a null pointer is always true}}
+    return array[1];
+  }
+  if (array == 0) // expected-warning {{comparison of array 'array' equal to a null pointer is always false}}
+    return 1;
+  return 0;
+}
+
+#define NULL (void*)0
+
+int test2(int* pointer, char ch, void * pv) {
+   if (!&pointer) {  // expected-warning {{address of 'pointer' will always evaluate to 'true'}}
+     return 0;
+   }
+
+   if (&pointer) {  // expected-warning {{address of 'pointer' will always evaluate to 'true'}}
+     return 0;
+   }
+
+   if (&pointer == NULL) {} // expected-warning {{comparison of address of 'pointer' equal to a null pointer is always false}}
+
+   if (&pointer != NULL) {} // expected-warning {{comparison of address of 'pointer' not equal to a null pointer is always true}}
+
+   return 1;
+}
+
+void test3() {
+   if (array) { } // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+   if (array != 0) {} // expected-warning {{comparison of array 'array' not equal to a null pointer is always true}}
+   if (!array) { } // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+   if (array == 0) {} // expected-warning {{comparison of array 'array' equal to a null pointer is always false}}
+
+   if (array[0] &&
+       array) {} // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+
+   if (array[0] ||
+       array) {} // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+
+   if (array[0] &&
+       !array) {} // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+   if (array[0] ||
+       !array) {} // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+
+   if (array && // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+       array[0]) {}
+   if (!array || // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+       array[0]) {}
+
+   if (array ||  // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+       (!array && array[0])) {} // expected-warning {{address of array 'array' will always evaluate to 'true'}}
+ }
+
+