This patch adds a fixit hint to -Wlogical-not-parentheses. When the LHS
has a location, it prints:
z.c: In function ‘int foo(int, int)’:
z.c:12:11: warning: logical not is only applied to the left hand side of
comparison [-Wlogical-not-parentheses]
r += !a == b;
^~
z.c:12:8: note: add parentheses around left hand side expression to silence
this warning
r += !a == b;
^~
( )
Bootstrapped/regtested on x86_64-linux and ppc64le-redhat-linux, ok for trunk?
2016-08-24 Marek Polacek <pola...@redhat.com>
* c-common.c (warn_logical_not_parentheses): Print fixit hints.
* c-common.h (warn_logical_not_parentheses): Update declaration.
* c-typeck.c (parser_build_binary_op): Pass LHS to
warn_logical_not_parentheses.
* parser.c (cp_parser_binary_expression): Pass LHS to
warn_logical_not_parentheses.
* c-c++-common/Wlogical-not-parentheses-2.c: New test.
diff --git gcc/c-family/c-common.c gcc/c-family/c-common.c
index 3feb910..a445df1 100644
--- gcc/c-family/c-common.c
+++ gcc/c-family/c-common.c
@@ -1485,7 +1485,7 @@ warn_tautological_cmp (location_t loc, enum tree_code
code, tree lhs, tree rhs)
void
warn_logical_not_parentheses (location_t location, enum tree_code code,
- tree rhs)
+ tree lhs, tree rhs)
{
if (TREE_CODE_CLASS (code) != tcc_comparison
|| TREE_TYPE (rhs) == NULL_TREE
@@ -1498,9 +1498,16 @@ warn_logical_not_parentheses (location_t location, enum
tree_code code,
&& integer_zerop (rhs))
return;
- warning_at (location, OPT_Wlogical_not_parentheses,
- "logical not is only applied to the left hand side of "
- "comparison");
+ if (warning_at (location, OPT_Wlogical_not_parentheses,
+ "logical not is only applied to the left hand side of "
+ "comparison")
+ && EXPR_HAS_LOCATION (lhs))
+ {
+ rich_location richloc (line_table, EXPR_LOCATION (lhs));
+ richloc.add_fixit_insert (EXPR_LOCATION (lhs), "( )");
+ inform_at_rich_loc (&richloc, "add parentheses around left hand side "
+ "expression to silence this warning");
+ }
}
/* Warn if EXP contains any computations whose results are not used.
diff --git gcc/c-family/c-common.h gcc/c-family/c-common.h
index bc22baa..42ce969 100644
--- gcc/c-family/c-common.h
+++ gcc/c-family/c-common.h
@@ -847,7 +847,8 @@ extern void overflow_warning (location_t, tree);
extern bool warn_if_unused_value (const_tree, location_t);
extern void warn_logical_operator (location_t, enum tree_code, tree,
enum tree_code, tree, enum tree_code, tree);
-extern void warn_logical_not_parentheses (location_t, enum tree_code, tree);
+extern void warn_logical_not_parentheses (location_t, enum tree_code, tree,
+ tree);
extern void warn_tautological_cmp (location_t, enum tree_code, tree, tree);
extern void check_main_parameter_types (tree decl);
extern bool c_determine_visibility (tree);
diff --git gcc/c/c-typeck.c gcc/c/c-typeck.c
index bc8728a..2f8d611 100644
--- gcc/c/c-typeck.c
+++ gcc/c/c-typeck.c
@@ -3696,7 +3696,7 @@ parser_build_binary_op (location_t location, enum
tree_code code,
while (1);
}
if (TREE_CODE (TREE_TYPE (t)) != BOOLEAN_TYPE)
- warn_logical_not_parentheses (location, code, arg2.value);
+ warn_logical_not_parentheses (location, code, arg1.value, arg2.value);
}
/* Warn about comparisons against string literals, with the exception
diff --git gcc/cp/parser.c gcc/cp/parser.c
index 690e928..d54cf8a 100644
--- gcc/cp/parser.c
+++ gcc/cp/parser.c
@@ -8922,7 +8922,7 @@ cp_parser_binary_expression (cp_parser* parser, bool
cast_p,
|| TREE_TYPE (current.lhs) == NULL_TREE
|| TREE_CODE (TREE_TYPE (current.lhs)) != BOOLEAN_TYPE))
warn_logical_not_parentheses (current.loc, current.tree_type,
- maybe_constant_value (rhs));
+ current.lhs, maybe_constant_value (rhs));
overload = NULL;
diff --git gcc/testsuite/c-c++-common/Wlogical-not-parentheses-2.c
gcc/testsuite/c-c++-common/Wlogical-not-parentheses-2.c
index e69de29..c5c2aac 100644
--- gcc/testsuite/c-c++-common/Wlogical-not-parentheses-2.c
+++ gcc/testsuite/c-c++-common/Wlogical-not-parentheses-2.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-Wlogical-not-parentheses -fdiagnostics-show-caret" } */
+
+ /* Test fixit hints. */
+
+int
+foo (int a, int b)
+{
+ int r = 0;
+ r += (!a) == b;
+ r += !a == b; /* { dg-warning "logical not is only applied" } */
+/* { dg-begin-multiline-output "" }
+ r += !a == b;
+ ^~
+ r += !a == b;
+ ^~
+ ( )
+ { dg-end-multiline-output "" } */
+ return r;
+}
Marek
