+
+/* Resolve an expression without changing any symbols/sub-expressions
+ used. */
+
+int
+resolve_expression (expressionS *expressionP)
+{
+ /* Help out with CSE. */
+ valueT final_val = expressionP->X_add_number;
+ symbolS *add_symbol = expressionP->X_add_symbol;
+ symbolS *orig_add_symbol = add_symbol;
+ symbolS *op_symbol = expressionP->X_op_symbol;
+ operatorT op = expressionP->X_op;
+ valueT left, right;
+ segT seg_left, seg_right;
+ fragS *frag_left, *frag_right;
+ offsetT frag_off;
+
+ switch (op)
+ {
+ default:
+ return 0;
+
+ case O_constant:
+ case O_register:
+ left = 0;
+ break;
+
+ case O_symbol:
+ case O_symbol_rva:
+ if (!snapshot_symbol (&add_symbol, &left, &seg_left, &frag_left))
+ return 0;
+
+ break;
+
+ case O_uminus:
+ case O_bit_not:
+ case O_logical_not:
+ if (!snapshot_symbol (&add_symbol, &left, &seg_left, &frag_left))
+ return 0;
+
+ if (seg_left != absolute_section)
+ return 0;
+
+ if (op == O_logical_not)
+ left = !left;
+ else if (op == O_uminus)
+ left = -left;
+ else
+ left = ~left;
+ op = O_constant;
+ break;
+
+ case O_multiply:
+ case O_divide:
+ case O_modulus:
+ case O_left_shift:
+ case O_right_shift:
+ case O_bit_inclusive_or:
+ case O_bit_or_not:
+ case O_bit_exclusive_or:
+ case O_bit_and:
+ case O_add:
+ case O_subtract:
+ case O_eq:
+ case O_ne:
+ case O_lt:
+ case O_le:
+ case O_ge:
+ case O_gt:
+ case O_logical_and:
+ case O_logical_or:
+ if (!snapshot_symbol (&add_symbol, &left, &seg_left, &frag_left)
+ || !snapshot_symbol (&op_symbol, &right, &seg_right, &frag_right))
+ return 0;
+
+ /* Simplify addition or subtraction of a constant by folding the
+ constant into X_add_number. */
+ if (op == O_add)
+ {
+ if (seg_right == absolute_section)
+ {
+ final_val += right;
+ op = O_symbol;
+ break;
+ }
+ else if (seg_left == absolute_section)
+ {
+ final_val += left;
+ left = right;
+ seg_left = seg_right;
+ add_symbol = op_symbol;
+ orig_add_symbol = expressionP->X_op_symbol;
+ op = O_symbol;
+ break;
+ }
+ }
+ else if (op == O_subtract)
+ {
+ if (seg_right == absolute_section)
+ {
+ final_val -= right;
+ op = O_symbol;
+ break;
+ }
+ }
+
+ /* Equality and non-equality tests are permitted on anything.
+ Subtraction, and other comparison operators are permitted if
+ both operands are in the same section.
+ Shifts by constant zero are permitted on anything.
+ Multiplies, bit-ors, and bit-ands with constant zero are
+ permitted on anything.
+ Multiplies and divides by constant one are permitted on
+ anything.
+ Binary operations with both operands being the same register
+ or undefined symbol are permitted if the result doesn't depend
+ on the input value.
+ Otherwise, both operands must be absolute. We already handled
+ the case of addition or subtraction of a constant above. */
+ frag_off = 0;
+ if (!(seg_left == absolute_section
+ && seg_right == absolute_section)
+ && !(op == O_eq || op == O_ne)
+ && !((op == O_subtract
+ || op == O_lt || op == O_le || op == O_ge || op == O_gt)
+ && seg_left == seg_right
+ && (finalize_syms
+ || frag_offset_fixed_p (frag_left, frag_right, &frag_off))
+ && (seg_left != reg_section || left == right)
+ && (seg_left != undefined_section || add_symbol == op_symbol)))
+ {
+ if ((seg_left == absolute_section && left == 0)
+ || (seg_right == absolute_section && right == 0))
+ {
+ if (op == O_bit_exclusive_or || op == O_bit_inclusive_or)
+ {
+ if (!(seg_right == absolute_section && right == 0))
+ {
+ seg_left = seg_right;
+ left = right;
+ add_symbol = op_symbol;
+ orig_add_symbol = expressionP->X_op_symbol;
+ }
+ op = O_symbol;
+ break;
+ }
+ else if (op == O_left_shift || op == O_right_shift)
+ {
+ if (!(seg_left == absolute_section && left == 0))
+ {
+ op = O_symbol;
+ break;
+ }
+ }
+ else if (op != O_multiply
+ && op != O_bit_or_not && op != O_bit_and)
+ return 0;
+ }
+ else if (op == O_multiply
+ && seg_left == absolute_section && left == 1)
+ {
+ seg_left = seg_right;
+ left = right;
+ add_symbol = op_symbol;
+ orig_add_symbol = expressionP->X_op_symbol;
+ op = O_symbol;
+ break;
+ }
+ else if ((op == O_multiply || op == O_divide)
+ && seg_right == absolute_section && right == 1)
+ {
+ op = O_symbol;
+ break;
+ }
+ else if (!(left == right
+ && ((seg_left == reg_section && seg_right == reg_section)
+ || (seg_left == undefined_section
+ && seg_right == undefined_section
+ && add_symbol == op_symbol))))
+ return 0;
+ else if (op == O_bit_and || op == O_bit_inclusive_or)
+ {
+ op = O_symbol;
+ break;
+ }
+ else if (op != O_bit_exclusive_or && op != O_bit_or_not)
+ return 0;
+ }
+
+ right += frag_off / OCTETS_PER_BYTE;
+ switch (op)
+ {
+ case O_add: left += right; break;
+ case O_subtract: left -= right; break;
+ case O_multiply: left *= right; break;
+ case O_divide:
+ if (right == 0)
+ return 0;
+ left = (offsetT) left / (offsetT) right;
+ break;
+ case O_modulus:
+ if (right == 0)
+ return 0;
+ left = (offsetT) left % (offsetT) right;
+ break;
+ case O_left_shift: left <<= right; break;
+ case O_right_shift: left >>= right; break;
+ case O_bit_inclusive_or: left |= right; break;
+ case O_bit_or_not: left |= ~right; break;
+ case O_bit_exclusive_or: left ^= right; break;
+ case O_bit_and: left &= right; break;
+ case O_eq:
+ case O_ne:
+ left = (left == right
+ && seg_left == seg_right
+ && (finalize_syms || frag_left == frag_right)
+ && (seg_left != undefined_section
+ || add_symbol == op_symbol)
+ ? ~ (valueT) 0 : 0);
+ if (op == O_ne)
+ left = ~left;
+ break;
+ case O_lt:
+ left = (offsetT) left < (offsetT) right ? ~ (valueT) 0 : 0;
+ break;
+ case O_le:
+ left = (offsetT) left <= (offsetT) right ? ~ (valueT) 0 : 0;
+ break;
+ case O_ge:
+ left = (offsetT) left >= (offsetT) right ? ~ (valueT) 0 : 0;
+ break;
+ case O_gt:
+ left = (offsetT) left > (offsetT) right ? ~ (valueT) 0 : 0;
+ break;
+ case O_logical_and: left = left && right; break;
+ case O_logical_or: left = left || right; break;
+ default: abort ();
+ }
+
+ op = O_constant;
+ break;
+ }
+
+ if (op == O_symbol)
+ {
+ if (seg_left == absolute_section)
+ op = O_constant;
+ else if (seg_left == reg_section && final_val == 0)
+ op = O_register;
+ else if (!symbol_same_p (add_symbol, orig_add_symbol))
+ final_val += left;
+ expressionP->X_add_symbol = add_symbol;
+ }
+ expressionP->X_op = op;
+
+ if (op == O_constant || op == O_register)
+ final_val += left;
+ expressionP->X_add_number = final_val;
+
+ return 1;
+}
projects / deliverable / binutils-gdb.git / blobdiff