/* Build expressions with type checking for C compiler.
- Copyright (C) 1987, 88, 91, 92, 93, 1994 Free Software Foundation, Inc.
+ Copyright (C) 1987, 88, 91, 92, 93, 94, 1995 Free Software Foundation, Inc.
This file is part of GNU CC.
/* Strip any conversions, additions, and subtractions, and see if
we are returning the address of a local variable. Warn if so. */
- while (TREE_CODE (inner) == NOP_EXPR
- || TREE_CODE (inner) == NON_LVALUE_EXPR
- || TREE_CODE (inner) == CONVERT_EXPR
- || TREE_CODE (inner) == PLUS_EXPR
- || TREE_CODE (inner) == MINUS_EXPR)
- inner = TREE_OPERAND (inner, 0);
-
- if (TREE_CODE (inner) == ADDR_EXPR)
+ while (1)
{
- inner = TREE_OPERAND (inner, 0);
+ switch (TREE_CODE (inner))
+ {
+ case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
+ case PLUS_EXPR:
+ inner = TREE_OPERAND (inner, 0);
+ continue;
+
+ case MINUS_EXPR:
+ /* If the second operand of the MINUS_EXPR has a pointer
+ type (or is converted from it), this may be valid, so
+ don't give a warning. */
+ {
+ tree op1 = TREE_OPERAND (inner, 1);
+
+ while (! POINTER_TYPE_P (TREE_TYPE (op1))
+ && (TREE_CODE (op1) == NOP_EXPR
+ || TREE_CODE (op1) == NON_LVALUE_EXPR
+ || TREE_CODE (op1) == CONVERT_EXPR))
+ op1 = TREE_OPERAND (op1, 0);
+
+ if (POINTER_TYPE_P (TREE_TYPE (op1)))
+ break;
- while (TREE_CODE_CLASS (TREE_CODE (inner)) == 'r')
- inner = TREE_OPERAND (inner, 0);
+ inner = TREE_OPERAND (inner, 0);
+ continue;
+ }
+
+ case ADDR_EXPR:
+ inner = TREE_OPERAND (inner, 0);
- if (TREE_CODE (inner) == VAR_DECL
- && ! DECL_EXTERNAL (inner)
- && ! TREE_STATIC (inner)
- && DECL_CONTEXT (inner) == current_function_decl)
- warning ("function returns address of local variable");
+ while (TREE_CODE_CLASS (TREE_CODE (inner)) == 'r')
+ inner = TREE_OPERAND (inner, 0);
+
+ if (TREE_CODE (inner) == VAR_DECL
+ && ! DECL_EXTERNAL (inner)
+ && ! TREE_STATIC (inner)
+ && DECL_CONTEXT (inner) == current_function_decl)
+ warning ("function returns address of local variable");
+ break;
+ }
+
+ break;
}
t = build (MODIFY_EXPR, TREE_TYPE (res), res, t);