r221702 - Patch to warn when logical evaluation of operand evalutes to a true value;
Fariborz Jahanian
fjahanian at apple.com
Tue Nov 11 11:59:17 PST 2014
Author: fjahanian
Date: Tue Nov 11 13:59:16 2014
New Revision: 221702
URL: http://llvm.org/viewvc/llvm-project?rev=221702&view=rev
Log:
Patch to warn when logical evaluation of operand evalutes to a true value;
That this is a c-only patch. c++ already has this warning.
This addresses rdar://18716393
Added:
cfe/trunk/test/Sema/warn-tautological-compare.c
Modified:
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/lib/Sema/SemaChecking.cpp
cfe/trunk/lib/Sema/SemaExpr.cpp
cfe/trunk/test/Analysis/logical-ops.c
cfe/trunk/test/Sema/exprs.c
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=221702&r1=221701&r2=221702&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Tue Nov 11 13:59:16 2014
@@ -8033,6 +8033,7 @@ public:
void DiagnoseAlwaysNonNullPointer(Expr *E,
Expr::NullPointerConstantKind NullType,
bool IsEqual, SourceRange Range);
+ void CheckAlwaysNonNullPointer(Expr *OrigExp);
/// type checking for vector binary operators.
QualType CheckVectorOperands(ExprResult &LHS, ExprResult &RHS,
Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=221702&r1=221701&r2=221702&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Tue Nov 11 13:59:16 2014
@@ -6748,6 +6748,17 @@ void Sema::DiagnoseAlwaysNonNullPointer(
<< FixItHint::CreateInsertion(getLocForEndOfToken(E->getLocEnd()), "()");
}
+void Sema::CheckAlwaysNonNullPointer(Expr *OrigExpr) {
+ if (const UnaryOperator *U = dyn_cast<UnaryOperator>(OrigExpr))
+ if (U->getOpcode() == UO_LNot)
+ return CheckAlwaysNonNullPointer(U->getSubExpr());
+
+ Expr *E = OrigExpr->IgnoreParenImpCasts();
+ QualType Source = E->getType();
+ if (Source->isPointerType() || Source->canDecayToPointerType())
+ DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false,
+ SourceRange());
+}
/// Diagnoses "dangerous" implicit conversions within the given
/// expression (which is a full expression). Implements -Wconversion
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=221702&r1=221701&r2=221702&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Tue Nov 11 13:59:16 2014
@@ -8413,7 +8413,10 @@ inline QualType Sema::CheckLogicalOperan
if (!LHS.get()->getType()->isScalarType() ||
!RHS.get()->getType()->isScalarType())
return InvalidOperands(Loc, LHS, RHS);
-
+
+ CheckAlwaysNonNullPointer(LHS.get());
+ CheckAlwaysNonNullPointer(RHS.get());
+
return Context.IntTy;
}
@@ -12971,6 +12974,7 @@ ExprResult Sema::CheckBooleanCondition(E
<< T << E->getSourceRange();
return ExprError();
}
+ CheckAlwaysNonNullPointer(E);
}
return E;
Modified: cfe/trunk/test/Analysis/logical-ops.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/logical-ops.c?rev=221702&r1=221701&r2=221702&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/logical-ops.c (original)
+++ cfe/trunk/test/Analysis/logical-ops.c Tue Nov 11 13:59:16 2014
@@ -36,4 +36,5 @@ int between(char *x) {
int undef(void) {} // expected-warning{{control reaches end of non-void function}}
void useUndef(void) { 0 || undef(); }
-void testPointer(void) { (void) (1 && testPointer && 0); }
+void testPointer(void) { (void) (1 && testPointer && 0); } // expected-warning {{address of function 'testPointer' will always evaluate to 'true'}} \
+ // expected-note {{prefix with the address-of operator to silence this warning}}
Modified: cfe/trunk/test/Sema/exprs.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/exprs.c?rev=221702&r1=221701&r2=221702&view=diff
==============================================================================
--- cfe/trunk/test/Sema/exprs.c (original)
+++ cfe/trunk/test/Sema/exprs.c Tue Nov 11 13:59:16 2014
@@ -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;
}
Added: cfe/trunk/test/Sema/warn-tautological-compare.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-tautological-compare.c?rev=221702&view=auto
==============================================================================
--- cfe/trunk/test/Sema/warn-tautological-compare.c (added)
+++ cfe/trunk/test/Sema/warn-tautological-compare.c Tue Nov 11 13:59:16 2014
@@ -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'}}
+ }
+
+
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