{
case CONSTRUCTOR:
case SIZEOF_EXPR:
+ case PAREN_SIZEOF_EXPR:
return;
case COMPOUND_EXPR:
c_common_init_ts (void)
{
MARK_TS_EXP (SIZEOF_EXPR);
+ MARK_TS_EXP (PAREN_SIZEOF_EXPR);
MARK_TS_EXP (C_MAYBE_CONST_EXPR);
MARK_TS_EXP (EXCESS_PRECISION_EXPR);
MARK_TS_EXP (BREAK_STMT);
or for the purpose of -Wsizeof-pointer-memaccess warning. */
DEFTREECODE (SIZEOF_EXPR, "sizeof_expr", tcc_expression, 1)
+/* Like above, but enclosed in parentheses. Used to suppress warnings. */
+DEFTREECODE (PAREN_SIZEOF_EXPR, "paren_sizeof_expr", tcc_expression, 1)
+
/* Used to represent a `for' statement. The operands are
FOR_INIT_STMT, FOR_COND, FOR_EXPR, FOR_BODY, and FOR_SCOPE,
respectively. */
extern bool warn_for_restrict (unsigned, tree *, unsigned);
extern void warn_for_address_or_pointer_of_packed_member (tree, tree);
extern void warn_parm_array_mismatch (location_t, tree, tree);
+extern void maybe_warn_sizeof_array_div (location_t, tree, tree, tree, tree);
/* Places where an lvalue, or modifiable lvalue, may be required.
Used to select diagnostic messages in lvalue_error and
inform (origloc, "previously declared as %s", curparmstr.c_str ());
}
}
+
+/* Warn about divisions of two sizeof operators when the first one is applied
+ to an array and the divisor does not equal the size of the array element.
+ For instance:
+
+ sizeof (ARR) / sizeof (OP)
+
+ ARR is the array argument of the first sizeof, ARR_TYPE is its ARRAY_TYPE.
+ OP1 is the whole second SIZEOF_EXPR, or its argument; TYPE1 is the type
+ of the second argument. */
+
+void
+maybe_warn_sizeof_array_div (location_t loc, tree arr, tree arr_type,
+ tree op1, tree type1)
+{
+ tree elt_type = TREE_TYPE (arr_type);
+
+ if (!warn_sizeof_array_div
+ /* Don't warn on multidimensional arrays. */
+ || TREE_CODE (elt_type) == ARRAY_TYPE)
+ return;
+
+ if (!tree_int_cst_equal (TYPE_SIZE (elt_type), TYPE_SIZE (type1)))
+ {
+ auto_diagnostic_group d;
+ if (warning_at (loc, OPT_Wsizeof_array_div,
+ "expression does not compute the number of "
+ "elements in this array; element type is "
+ "%qT, not %qT", elt_type, type1))
+ {
+ if (EXPR_HAS_LOCATION (op1))
+ {
+ location_t op1_loc = EXPR_LOCATION (op1);
+ gcc_rich_location richloc (op1_loc);
+ richloc.add_fixit_insert_before (op1_loc, "(");
+ richloc.add_fixit_insert_after (op1_loc, ")");
+ inform (&richloc, "add parentheses around %qE to "
+ "silence this warning", op1);
+ }
+ else
+ inform (loc, "add parentheses around the second %<sizeof%> "
+ "to silence this warning");
+ if (DECL_P (arr))
+ inform (DECL_SOURCE_LOCATION (arr), "array %qD declared here", arr);
+ }
+ }
+}
C ObjC C++ ObjC++ Var(warn_sizeof_pointer_div) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about suspicious divisions of two sizeof expressions that don't work correctly with pointers.
+Wsizeof-array-div
+C ObjC C++ ObjC++ Var(warn_sizeof_array_div) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
+Warn about divisions of two sizeof operators when the first one is applied
+to an array and the divisor does not equal the size of the array element.
+
Wsizeof-pointer-memaccess
C ObjC C++ ObjC++ Var(warn_sizeof_pointer_memaccess) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about suspicious length parameters to certain string functions if the argument uses sizeof.
enum tree_code op;
/* The source location of this operation. */
location_t loc;
- /* The sizeof argument if expr.original_code == SIZEOF_EXPR. */
+ /* The sizeof argument if expr.original_code == {PAREN_,}SIZEOF_EXPR. */
tree sizeof_arg;
} stack[NUM_PRECS];
int sp;
c_inhibit_evaluation_warnings -= (stack[sp - 1].expr.value \
== truthvalue_true_node); \
break; \
- case TRUNC_DIV_EXPR: \
- if (stack[sp - 1].expr.original_code == SIZEOF_EXPR \
- && stack[sp].expr.original_code == SIZEOF_EXPR) \
+ case TRUNC_DIV_EXPR: \
+ if ((stack[sp - 1].expr.original_code == SIZEOF_EXPR \
+ || stack[sp - 1].expr.original_code == PAREN_SIZEOF_EXPR) \
+ && (stack[sp].expr.original_code == SIZEOF_EXPR \
+ || stack[sp].expr.original_code == PAREN_SIZEOF_EXPR)) \
{ \
tree type0 = stack[sp - 1].sizeof_arg; \
tree type1 = stack[sp].sizeof_arg; \
&& !(TREE_CODE (first_arg) == PARM_DECL \
&& C_ARRAY_PARAMETER (first_arg) \
&& warn_sizeof_array_argument)) \
- { \
- auto_diagnostic_group d; \
- if (warning_at (stack[sp].loc, OPT_Wsizeof_pointer_div, \
- "division %<sizeof (%T) / sizeof (%T)%> " \
- "does not compute the number of array " \
- "elements", \
- type0, type1)) \
- if (DECL_P (first_arg)) \
- inform (DECL_SOURCE_LOCATION (first_arg), \
- "first %<sizeof%> operand was declared here"); \
- } \
- } \
+ { \
+ auto_diagnostic_group d; \
+ if (warning_at (stack[sp].loc, OPT_Wsizeof_pointer_div, \
+ "division %<sizeof (%T) / sizeof (%T)%> " \
+ "does not compute the number of array " \
+ "elements", \
+ type0, type1)) \
+ if (DECL_P (first_arg)) \
+ inform (DECL_SOURCE_LOCATION (first_arg), \
+ "first %<sizeof%> operand was declared here"); \
+ } \
+ else if (TREE_CODE (type0) == ARRAY_TYPE \
+ && !char_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (type0))) \
+ && stack[sp].expr.original_code != PAREN_SIZEOF_EXPR) \
+ maybe_warn_sizeof_array_div (stack[sp].loc, first_arg, type0, \
+ stack[sp].sizeof_arg, type1); \
+ } \
break; \
default: \
break; \
if (expr.original_code != C_MAYBE_CONST_EXPR
&& expr.original_code != SIZEOF_EXPR)
expr.original_code = ERROR_MARK;
+ /* Remember that we saw ( ) around the sizeof. */
+ if (expr.original_code == SIZEOF_EXPR)
+ expr.original_code = PAREN_SIZEOF_EXPR;
/* Don't change EXPR.ORIGINAL_TYPE. */
location_t loc_close_paren = c_parser_peek_token (parser)->location;
set_c_expr_source_range (&expr, loc_open_paren, loc_close_paren);
if (locations)
locations->safe_push (expr.get_location ());
if (sizeof_arg != NULL
- && expr.original_code == SIZEOF_EXPR)
+ && (expr.original_code == SIZEOF_EXPR
+ || expr.original_code == PAREN_SIZEOF_EXPR))
{
sizeof_arg[0] = c_last_sizeof_arg;
sizeof_arg_loc[0] = c_last_sizeof_loc;
locations->safe_push (expr.get_location ());
if (++idx < 3
&& sizeof_arg != NULL
- && expr.original_code == SIZEOF_EXPR)
+ && (expr.original_code == SIZEOF_EXPR
+ || expr.original_code == PAREN_SIZEOF_EXPR))
{
sizeof_arg[idx] = c_last_sizeof_arg;
sizeof_arg_loc[idx] = c_last_sizeof_loc;
extern struct c_switch *c_switch_stack;
+extern bool char_type_p (tree);
extern tree c_objc_common_truthvalue_conversion (location_t, tree);
extern tree require_complete_type (location_t, tree);
extern bool same_translation_unit_p (const_tree, const_tree);
/* Returns true if TYPE is a character type, *not* including wchar_t. */
-static bool
+bool
char_type_p (tree type)
{
return (type == char_type_node
{
tree type0 = TREE_OPERAND (op0, 0);
tree type1 = TREE_OPERAND (op1, 0);
- tree first_arg = type0;
+ tree first_arg = tree_strip_any_location_wrapper (type0);
if (!TYPE_P (type0))
type0 = TREE_TYPE (type0);
if (!TYPE_P (type1))
type1 = TREE_TYPE (type1);
if (INDIRECT_TYPE_P (type0) && same_type_p (TREE_TYPE (type0), type1))
{
- STRIP_ANY_LOCATION_WRAPPER (first_arg);
if (!(TREE_CODE (first_arg) == PARM_DECL
&& DECL_ARRAY_PARAMETER_P (first_arg)
&& warn_sizeof_array_argument)
"first %<sizeof%> operand was declared here");
}
}
+ else if (TREE_CODE (type0) == ARRAY_TYPE
+ && !char_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (type0)))
+ /* Set by finish_parenthesized_expr. */
+ && !TREE_NO_WARNING (op1)
+ && (complain & tf_warning))
+ maybe_warn_sizeof_array_div (location, first_arg, type0,
+ op1, non_reference (type1));
}
if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
-Wno-shift-overflow -Wshift-overflow=@var{n} @gol
-Wsign-compare -Wsign-conversion @gol
-Wno-sizeof-array-argument @gol
+-Wsizeof-array-div @gol
-Wsizeof-pointer-div -Wsizeof-pointer-memaccess @gol
-Wstack-protector -Wstack-usage=@var{byte-size} -Wstrict-aliasing @gol
-Wstrict-aliasing=n -Wstrict-overflow -Wstrict-overflow=@var{n} @gol
-Wreturn-type @gol
-Wsequence-point @gol
-Wsign-compare @r{(only in C++)} @gol
+-Wsizeof-array-div @gol
-Wsizeof-pointer-div @gol
-Wsizeof-pointer-memaccess @gol
-Wstrict-aliasing @gol
@opindex Wscalar-storage-order
Do not warn on suspicious constructs involving reverse scalar storage order.
+@item -Wsizeof-array-div
+@opindex Wsizeof-array-div
+@opindex Wno-sizeof-array-div
+Warn about divisions of two sizeof operators when the first one is applied
+to an array and the divisor does not equal the size of the array element.
+In such a case, the computation will not yield the number of elements in the
+array, which is likely what the user intended. This warning warns e.g. about
+@smallexample
+int fn ()
+@{
+ int arr[10];
+ return sizeof (arr) / sizeof (short);
+@}
+@end smallexample
+
+This warning is enabled by @option{-Wall}.
+
@item -Wsizeof-pointer-div
@opindex Wsizeof-pointer-div
@opindex Wno-sizeof-pointer-div
--- /dev/null
+/* PR c++/91741 */
+/* { dg-do compile } */
+/* { dg-options "-Wall" } */
+
+typedef int T;
+
+int
+fn (int ap[])
+{
+ int arr[10];
+ int *arr2[10];
+ int *p = &arr[0];
+ int r = 0;
+
+ r += sizeof (arr) / sizeof (*arr);
+ r += sizeof (arr) / sizeof (p); /* { dg-warning "expression does not compute" } */
+ r += sizeof (arr) / sizeof p; /* { dg-warning "expression does not compute" } */
+ r += sizeof (arr) / (sizeof p);
+ r += sizeof (arr) / (sizeof (p));
+ r += sizeof (arr2) / sizeof p;
+ r += sizeof (arr2) / sizeof (int); /* { dg-warning "expression does not compute" } */
+ r += sizeof (arr2) / sizeof (int *);
+ r += sizeof (arr2) / sizeof (short *);
+ r += sizeof (arr) / sizeof (int);
+ r += sizeof (arr) / sizeof (unsigned int);
+ r += sizeof (arr) / sizeof (T);
+ r += sizeof (arr) / sizeof (short); /* { dg-warning "expression does not compute" } */
+ r += sizeof (arr) / (sizeof (short));
+
+ r += sizeof (ap) / sizeof (char); /* { dg-warning ".sizeof. on array function parameter" } */
+
+ const char arr3[] = "foo";
+ r += sizeof (arr3) / sizeof(char);
+ r += sizeof (arr3) / sizeof(int);
+ r += sizeof (arr3) / sizeof (*arr3);
+
+ int arr4[5][5];
+ r += sizeof (arr4) / sizeof (arr4[0]);
+ r += sizeof (arr4) / sizeof (*arr4);
+ r += sizeof (arr4) / sizeof (**arr4);
+ r += sizeof (arr4) / sizeof (int *);
+ r += sizeof (arr4) / sizeof (int);
+ r += sizeof (arr4) / sizeof (short int);
+
+ T arr5[10];
+ r += sizeof (arr5) / sizeof (T);
+ r += sizeof (arr5) / sizeof (int);
+ r += sizeof (arr5) / sizeof (short); /* { dg-warning "expression does not compute" } */
+
+ double arr6[10];
+ r += sizeof (arr6) / sizeof (double);
+ r += sizeof (arr6) / sizeof (float); /* { dg-warning "expression does not compute" } */
+ r += sizeof (arr6) / sizeof (*arr6);
+
+ return r;
+}
i += sizeof(array) / sizeof(array[0]);
i += (sizeof(array)) / (sizeof(array[0]));
i += sizeof(array) / sizeof(int);
- i += sizeof(array) / sizeof(char);
+ i += sizeof(array) / sizeof(char); /* { dg-warning "expression does not compute" } */
i += sizeof(*array) / sizeof(char);
i += sizeof(array[0]) / sizeof(char);
return i;
--- /dev/null
+// PR c++/91741
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wall" }
+
+int
+fn1 ()
+{
+ int arr[10];
+ return sizeof (arr) / sizeof (decltype(arr[0]));
+}
+
+template<typename T, int N>
+int fn2 (T (&arr)[N])
+{
+ return sizeof (arr) / sizeof (T);
+}
+
+template<typename T, int N>
+int fn3 (T (&arr)[N])
+{
+ return sizeof (arr) / sizeof (bool); // { dg-warning "expression does not compute" }
+}
+
+template<typename U, int N, typename T>
+int fn4 (T (&arr)[N])
+{
+ return sizeof (arr) / sizeof (U); // { dg-warning "expression does not compute" }
+}
+
+void
+fn ()
+{
+ int arr[10];
+ fn2 (arr);
+ fn3 (arr);
+ fn4<short> (arr);
+}
--- /dev/null
+// PR c++/91741
+// { dg-do compile }
+// { dg-options "-Wall" }
+// From <https://www.viva64.com/en/examples/v706/>.
+
+const int kBaudrates[] = { 50, 75, 110 };
+
+void
+foo ()
+{
+ for(int i = sizeof(kBaudrates) / sizeof(char*); // { dg-warning "expression does not compute" }
+ --i >= 0;)
+ {
+ }
+}
projects / gcc.git / commitdiff