[PATCH 10/16] fix index conversions in evaluate_ptr_add()

[Al Viro]

index may need to be expanded

Signed-off-by: Al Viro <[EMAIL PROTECTED]>
---
 evaluate.c |   92 ++++++++++++++++++++++++++++++++---------------------------
 1 files changed, 50 insertions(+), 42 deletions(-)

diff --git a/evaluate.c b/evaluate.c
index 79f1ac9..6cb29ff 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -559,27 +559,12 @@ static int ptr_object_size(struct symbol *ptr_type)
        return ptr_type->bit_size;
 }
 
-static inline void want_int(struct expression **expr, struct symbol **ctype)
+static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol 
*ctype, struct symbol *itype)
 {
-       int class = classify_type((*expr)->ctype, ctype);
-
-       if (!(class & TYPE_RESTRICT))
-               return;
-       warning((*expr)->pos, "restricted degrades to integer");
-       if (class & TYPE_FOULED)        /* unfoul it first */
-               (*ctype) = (*ctype)->ctype.base_type;
-       (*ctype) = (*ctype)->ctype.base_type;   /* get to arithmetic type */
-       *expr = cast_to(*expr, *ctype);
-}
-
-static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol 
*ctype, struct expression **ip)
-{
-       struct expression *i = *ip;
-       struct symbol *itype;
+       struct expression *index = expr->right;
+       int multiply;
        int bit_size;
 
-       want_int(&i, &itype);
-
        examine_symbol_type(ctype);
 
        if (!ctype->ctype.base_type) {
@@ -589,31 +574,48 @@ static struct symbol *evaluate_ptr_add(struct expression 
*expr, struct symbol *c
 
        /* Get the size of whatever the pointer points to */
        bit_size = ptr_object_size(ctype);
+       multiply = bit_size >> 3;
+
+       expr->ctype = ctype;
+
+       if (multiply == 1 && itype->bit_size >= bits_in_pointer)
+               return ctype;
 
-       if (bit_size > bits_in_char) {
-               int multiply = bit_size >> 3;
+       if (index->type == EXPR_VALUE) {
                struct expression *val = alloc_expression(expr->pos, 
EXPR_VALUE);
+               unsigned long long v = index->value, mask;
+               mask = 1ULL << (itype->bit_size - 1);
+               if (v & mask)
+                       v |= -mask;
+               else
+                       v &= mask - 1;
+               v *= multiply;
+               mask = 1ULL << (bits_in_pointer - 1);
+               v &= mask | (mask - 1);
+               val->value = v;
+               val->ctype = ssize_t_ctype;
+               expr->right = val;
+               return ctype;
+       }
 
-               if (i->type == EXPR_VALUE) {
-                       val->value = i->value * multiply;
-                       val->ctype = size_t_ctype;
-                       *ip = val;
-               } else {
-                       struct expression *mul = alloc_expression(expr->pos, 
EXPR_BINOP);
+       if (itype->bit_size < bits_in_pointer)
+               index = cast_to(index, ssize_t_ctype);
 
-                       val->ctype = size_t_ctype;
-                       val->value = bit_size >> 3;
+       if (multiply > 1) {
+               struct expression *val = alloc_expression(expr->pos, 
EXPR_VALUE);
+               struct expression *mul = alloc_expression(expr->pos, 
EXPR_BINOP);
 
-                       mul->op = '*';
-                       mul->ctype = size_t_ctype;
-                       mul->left = i;
-                       mul->right = val;
+               val->ctype = ssize_t_ctype;
+               val->value = multiply;
 
-                       *ip = mul;
-               }
+               mul->op = '*';
+               mul->ctype = ssize_t_ctype;
+               mul->left = index;
+               mul->right = val;
+               index = mul;
        }
 
-       expr->ctype = ctype;    
+       expr->right = index;
        return ctype;
 }
 
@@ -919,14 +921,19 @@ static struct symbol *evaluate_binop(struct expression 
*expr)
        }
 
        /* pointer (+|-) integer */
-       if (lclass & TYPE_PTR && is_int(rclass) && (op == '+' || op == '-'))
-               return evaluate_ptr_add(expr, degenerate(expr->left),
-                                       &expr->right);
+       if (lclass & TYPE_PTR && is_int(rclass) && (op == '+' || op == '-')) {
+               unrestrict(expr->right, rclass, &rtype);
+               return evaluate_ptr_add(expr, degenerate(expr->left), rtype);
+       }
 
        /* integer + pointer */
-       if (rclass & TYPE_PTR && is_int(lclass) && op == '+')
-               return evaluate_ptr_add(expr, degenerate(expr->right),
-                                       &expr->left);
+       if (rclass & TYPE_PTR && is_int(lclass) && op == '+') {
+               struct expression *index = expr->left;
+               unrestrict(index, lclass, &ltype);
+               expr->left = expr->right;
+               expr->right = index;
+               return evaluate_ptr_add(expr, degenerate(expr->left), ltype);
+       }
 
        /* pointer - pointer */
        if (lclass & rclass & TYPE_PTR && expr->op == '-')
@@ -1118,7 +1125,8 @@ static int evaluate_assign_op(struct expression *expr)
        }
        if (tclass & TYPE_PTR && is_int(sclass)) {
                if (op == SPECIAL_ADD_ASSIGN || op == SPECIAL_SUB_ASSIGN) {
-                       evaluate_ptr_add(expr, target, &expr->right);
+                       unrestrict(expr->right, sclass, &s);
+                       evaluate_ptr_add(expr, target, s);
                        return 1;
                }
                expression_error(expr, "invalid pointer assignment");
-- 
1.5.0-rc2.GIT


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