| - Ping.
- Thanks, Fairborz Begin forwarded message:
Subject: Re: patch for warning on logical negation with known result
Date: October 24, 2014 at 2:08:10 PM PDT
Minor change. I should not bail out early when types of implicit cast and its sub _expression_ are identical as implicit cast may be for lvalue to rvalue conversion. This showed up for this test case (with old patch warning is not being issued).
__attribute__((__nonnull__)) void test1(void *nonnull) { if (nonnull) {} }
|
Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h (revision 220567)
+++ include/clang/Sema/Sema.h (working copy)
@@ -7975,6 +7975,7 @@
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,
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp (revision 220567)
+++ lib/Sema/SemaChecking.cpp (working copy)
@@ -6778,6 +6778,21 @@
<< 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();
+ if (E == OrigExpr)
+ return;
+ QualType Target = OrigExpr->getType();
+ QualType Source = E->getType();
+ if (Target->isPointerType() &&
+ (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
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp (revision 220567)
+++ lib/Sema/SemaExpr.cpp (working copy)
@@ -8412,7 +8412,10 @@
if (!LHS.get()->getType()->isScalarType() ||
!RHS.get()->getType()->isScalarType())
return InvalidOperands(Loc, LHS, RHS);
-
+
+ CheckAlwaysNonNullPointer(LHS.get());
+ CheckAlwaysNonNullPointer(RHS.get());
+
return Context.IntTy;
}
@@ -12964,6 +12967,7 @@
<< T << E->getSourceRange();
return ExprError();
}
+ CheckAlwaysNonNullPointer(E);
}
return E;
Index: test/Analysis/logical-ops.c
===================================================================
--- test/Analysis/logical-ops.c (revision 220567)
+++ test/Analysis/logical-ops.c (working copy)
@@ -36,4 +36,5 @@
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}}
Index: test/Sema/exprs.c
===================================================================
--- test/Sema/exprs.c (revision 220567)
+++ test/Sema/exprs.c (working copy)
@@ -244,6 +244,10 @@
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;
}
Index: test/Sema/warn-tautological-compare.c
===================================================================
--- test/Sema/warn-tautological-compare.c (revision 0)
+++ test/Sema/warn-tautological-compare.c (working copy)
@@ -0,0 +1,81 @@
+// 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) __attribute__((nonnull(1, 3)));
+int test2(int* pointer, char ch, void * pv) {
+ if (!pointer) { // expected-warning {{nonnull parameter 'pointer' will
always evaluate to 'true'}}
+ return 0;
+ }
+
+ if (pointer) { // expected-warning {{nonnull parameter 'pointer' will
always evaluate to 'true'}}
+ return 0;
+ }
+
+ if (pointer == NULL) {} // expected-warning {{comparison of nonnull
parameter 'pointer' equal to a null pointer is always false}}
+
+ if (pointer != NULL) {} // expected-warning {{comparison of nonnull
parameter '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'}}
+ }
+
+
- Fariborz
Thanks for the review. Here is the updated patch.
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