Add a new warning to -Wliteral-conversion to catch cases where a string literal
is cast to a boolean. An exception has been made for string literals in
logical expressions to allow the common case of use in assert statements.
bool x;
x = "hi"; // Warn here
void foo(bool x);
foo("hi"); // Warn here
assert(0 && "error");
assert("error); // Warn here
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140405 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 57e4285..b0f6c93 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -1474,6 +1474,9 @@
"implicit conversion turns literal floating-point number into integer: "
"%0 to %1">,
InGroup<DiagGroup<"literal-conversion">>, DefaultIgnore;
+def warn_impcast_string_literal_to_bool : Warning<
+ "implicit conversion turns string literal into bool: %0 to %1">,
+ InGroup<DiagGroup<"literal-conversion">>, DefaultIgnore;
def note_fix_integral_float_as_integer : Note<
"this can be rewritten as an integer literal with the exact same value">;
def warn_impcast_different_enum_types : Warning<
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 052ef3b..5de43bb 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -3237,9 +3237,17 @@
if (CC.isInvalid())
return;
- // Never diagnose implicit casts to bool.
- if (Target->isSpecificBuiltinType(BuiltinType::Bool))
- return;
+ // Diagnose implicit casts to bool.
+ if (Target->isSpecificBuiltinType(BuiltinType::Bool)) {
+ if (isa<StringLiteral>(E))
+ // Warn on string literal to bool. Checks for string literals in logical
+ // expressions, for instances, assert(0 && "error here"), is prevented
+ // by a check in AnalyzeImplicitConversions().
+ return DiagnoseImpCast(S, E, T, CC,
+ diag::warn_impcast_string_literal_to_bool);
+ else // Other casts to bool are not checked.
+ return;
+ }
// Strip vector types.
if (isa<VectorType>(Source)) {
@@ -3508,8 +3516,16 @@
// Now just recurse over the expression's children.
CC = E->getExprLoc();
- for (Stmt::child_range I = E->children(); I; ++I)
- AnalyzeImplicitConversions(S, cast<Expr>(*I), CC);
+ BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
+ bool IsLogicalOperator = BO && BO->isLogicalOp();
+ for (Stmt::child_range I = E->children(); I; ++I) {
+ Expr *ChildExpr = cast<Expr>(*I);
+ if (IsLogicalOperator &&
+ isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
+ // Ignore checking string literals that are in logical operators.
+ continue;
+ AnalyzeImplicitConversions(S, ChildExpr, CC);
+ }
}
} // end anonymous namespace
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 3beb51c..3fb8df6 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -4643,7 +4643,7 @@
if (FullExpr.isInvalid())
return ExprError();
- CheckImplicitConversions(FullExpr.get());
+ CheckImplicitConversions(FullExpr.get(), FullExpr.get()->getExprLoc());
return MaybeCreateExprWithCleanups(FullExpr);
}
diff --git a/test/SemaCXX/warn-literal-conversion.cpp b/test/SemaCXX/warn-literal-conversion.cpp
index 3fc8a6f..c225aa4 100644
--- a/test/SemaCXX/warn-literal-conversion.cpp
+++ b/test/SemaCXX/warn-literal-conversion.cpp
@@ -43,3 +43,19 @@
int y = (24*60*60) * 0.25;
int pennies = 123.45 * 100;
}
+
+// Warn on cases where a string literal is converted into a bool.
+// An exception is made for this in logical operators.
+void assert(bool condition);
+void test1() {
+ bool b0 = "hi"; // expected-warning{{implicit conversion turns string literal into bool: 'const char [3]' to 'bool'}}
+ b0 = ""; // expected-warning{{implicit conversion turns string literal into bool: 'const char [1]' to 'bool'}}
+ b0 = 0 && "";
+ assert("error"); // expected-warning{{implicit conversion turns string literal into bool: 'const char [6]' to 'bool'}}
+ assert(0 && "error");
+
+ while("hi") {} // expected-warning{{implicit conversion turns string literal into bool: 'const char [3]' to 'bool'}}
+ do {} while("hi"); // expected-warning{{implicit conversion turns string literal into bool: 'const char [3]' to 'bool'}}
+ for (;"hi";); // expected-warning{{implicit conversion turns string literal into bool: 'const char [3]' to 'bool'}}
+ if("hi") {} // expected-warning{{implicit conversion turns string literal into bool: 'const char [3]' to 'bool'}}
+}
