diff options
Diffstat (limited to 'ld/ldexp.c')
| -rw-r--r-- | ld/ldexp.c | 97 |
1 files changed, 97 insertions, 0 deletions
@@ -790,6 +790,89 @@ fold_name (etree_type *tree) } } +/* Return true if TREE is '.'. */ + +static bfd_boolean +is_dot (const etree_type *tree) +{ + return (tree->type.node_class == etree_name + && tree->type.node_code == NAME + && tree->name.name[0] == '.' + && tree->name.name[1] == 0); +} + +/* Return true if TREE is a constant equal to VAL. */ + +static bfd_boolean +is_value (const etree_type *tree, bfd_vma val) +{ + return (tree->type.node_class == etree_value + && tree->value.value == val); +} + +/* Return true if TREE is an absolute symbol equal to VAL defined in + a linker script. */ + +static bfd_boolean +is_sym_value (const etree_type *tree, bfd_vma val) +{ + struct bfd_link_hash_entry *h; + struct lang_definedness_hash_entry *def; + + return (tree->type.node_class == etree_name + && tree->type.node_code == NAME + && (def = lang_symbol_defined (tree->name.name)) != NULL + && def->by_script + && def->iteration == (lang_statement_iteration & 1) + && (h = bfd_wrapped_link_hash_lookup (link_info.output_bfd, + &link_info, + tree->name.name, + FALSE, FALSE, TRUE)) != NULL + && h->type == bfd_link_hash_defined + && h->u.def.section == bfd_abs_section_ptr + && h->u.def.value == val); +} + +/* Return true if TREE is ". != 0". */ + +static bfd_boolean +is_dot_ne_0 (const etree_type *tree) +{ + return (tree->type.node_class == etree_binary + && tree->type.node_code == NE + && is_dot (tree->binary.lhs) + && is_value (tree->binary.rhs, 0)); +} + +/* Return true if TREE is ". = . + 0" or ". = . + sym" where sym is an + absolute constant with value 0 defined in a linker script. */ + +static bfd_boolean +is_dot_plus_0 (const etree_type *tree) +{ + return (tree->type.node_class == etree_binary + && tree->type.node_code == '+' + && is_dot (tree->binary.lhs) + && (is_value (tree->binary.rhs, 0) + || is_sym_value (tree->binary.rhs, 0))); +} + +/* Return true if TREE is "ALIGN (. != 0 ? some_expression : 1)". */ + +static bfd_boolean +is_align_conditional (const etree_type *tree) +{ + if (tree->type.node_class == etree_unary + && tree->type.node_code == ALIGN_K) + { + tree = tree->unary.child; + return (tree->type.node_class == etree_trinary + && is_dot_ne_0 (tree->trinary.cond) + && is_value (tree->trinary.rhs, 1)); + } + return 0; +} + static void exp_fold_tree_1 (etree_type *tree) { @@ -854,6 +937,20 @@ exp_fold_tree_1 (etree_type *tree) exp_fold_tree_1 (tree->assign.src); expld.assigning_to_dot = FALSE; + /* If we are assigning to dot inside an output section + arrange to keep the section, except for certain + expressions that evaluate to zero. We ignore . = 0, + . = . + 0, and . = ALIGN (. != 0 ? expr : 1). */ + if (expld.phase == lang_mark_phase_enum + && expld.section != bfd_abs_section_ptr + && !(expld.result.valid_p + && expld.result.value == 0 + && (is_value (tree->assign.src, 0) + || is_sym_value (tree->assign.src, 0) + || is_dot_plus_0 (tree->assign.src) + || is_align_conditional (tree->assign.src)))) + expld.section->flags |= SEC_KEEP; + if (!expld.result.valid_p) { if (expld.phase != lang_mark_phase_enum) |