/* This module handles expression trees.
- Copyright (C) 1991-2015 Free Software Foundation, Inc.
+ Copyright (C) 1991-2017 Free Software Foundation, Inc.
Written by Steve Chamberlain of Cygnus Support <sac@cygnus.com>.
This file is part of the GNU Binutils.
struct ldexp_control expld;
/* This structure records symbols for which we need to keep track of
- definedness for use in the DEFINED () test. */
+ definedness for use in the DEFINED () test. It is also used in
+ making absolute symbols section relative late in the link. */
struct definedness_hash_entry
{
struct bfd_hash_entry root;
+
+ /* If this symbol was assigned from "dot" outside of an output
+ section statement, the section we'd like it relative to. */
+ asection *final_sec;
+
+ /* Symbol was defined by an object file. */
unsigned int by_object : 1;
+
+ /* Symbols was defined by a script. */
unsigned int by_script : 1;
+
+ /* Low bit of iteration count. Symbols with matching iteration have
+ been defined in this pass over the script. */
unsigned int iteration : 1;
};
static const struct
{
token_code_type code;
- const char * name;
+ const char *name;
}
table[] =
{
if (expld.result.section != NULL)
expld.result.value += expld.result.section->vma;
expld.result.section = bfd_abs_section_ptr;
+ expld.rel_from_abs = FALSE;
}
static void
{
asection *s = expld.section;
- if (s == bfd_abs_section_ptr && expld.phase == lang_final_phase_enum)
- s = section_for_dot ();
+ expld.rel_from_abs = TRUE;
expld.result.valid_p = TRUE;
expld.result.value = value - s->vma;
expld.result.str = NULL;
defentry->by_script = 1;
defentry->iteration = lang_statement_iteration;
+ defentry->final_sec = bfd_abs_section_ptr;
+ if (expld.phase == lang_final_phase_enum
+ && expld.rel_from_abs
+ && expld.result.section == bfd_abs_section_ptr)
+ defentry->final_sec = section_for_dot ();
return ret;
}
}
}
+/* Arithmetic operators, bitwise AND, bitwise OR and XOR keep the
+ section of one of their operands only when the other operand is a
+ plain number. Losing the section when operating on two symbols,
+ ie. a result of a plain number, is required for subtraction and
+ XOR. It's justifiable for the other operations on the grounds that
+ adding, multiplying etc. two section relative values does not
+ really make sense unless they are just treated as numbers.
+ The same argument could be made for many expressions involving one
+ symbol and a number. For example, "1 << x" and "100 / x" probably
+ should not be given the section of x. The trouble is that if we
+ fuss about such things the rules become complex and it is onerous
+ to document ld expression evaluation. */
+static void
+arith_result_section (const etree_value_type *lhs)
+{
+ if (expld.result.section == lhs->section)
+ {
+ if (expld.section == bfd_abs_section_ptr
+ && !config.sane_expr)
+ /* Duplicate the insanity in exp_fold_tree_1 case etree_value. */
+ expld.result.section = bfd_abs_section_ptr;
+ else
+ expld.result.section = NULL;
+ }
+}
+
static void
fold_binary (etree_type *tree)
{
if (!seg->used
&& config.magic_demand_paged
&& (seg->value % config.maxpagesize) != 0)
- einfo (_("%P: warning: address of `%s' isn't multiple of maximum page size\n"),
+ einfo (_("%P: warning: address of `%s' "
+ "isn't multiple of maximum page size\n"),
segment_name);
seg->used = TRUE;
new_rel_from_abs (seg->value);
switch (tree->type.node_code)
{
- /* Arithmetic operators, bitwise AND, bitwise OR and XOR
- keep the section of one of their operands only when the
- other operand is a plain number. Losing the section when
- operating on two symbols, ie. a result of a plain number,
- is required for subtraction and XOR. It's justifiable
- for the other operations on the grounds that adding,
- multiplying etc. two section relative values does not
- really make sense unless they are just treated as
- numbers.
- The same argument could be made for many expressions
- involving one symbol and a number. For example,
- "1 << x" and "100 / x" probably should not be given the
- section of x. The trouble is that if we fuss about such
- things the rules become complex and it is onerous to
- document ld expression evaluation. */
#define BOP(x, y) \
case x: \
expld.result.value = lhs.value y expld.result.value; \
- if (expld.result.section == lhs.section) \
- expld.result.section = NULL; \
+ arith_result_section (&lhs); \
break;
/* Comparison operators, logical AND, and logical OR always
% (bfd_signed_vma) expld.result.value);
else if (expld.phase != lang_mark_phase_enum)
einfo (_("%F%S %% by zero\n"), tree->binary.rhs);
- if (expld.result.section == lhs.section)
- expld.result.section = NULL;
+ arith_result_section (&lhs);
break;
case '/':
/ (bfd_signed_vma) expld.result.value);
else if (expld.phase != lang_mark_phase_enum)
einfo (_("%F%S / by zero\n"), tree->binary.rhs);
- if (expld.result.section == lhs.section)
- expld.result.section = NULL;
+ arith_result_section (&lhs);
break;
case MAX_K:
case LENGTH:
{
if (expld.phase != lang_first_phase_enum)
- {
- lang_memory_region_type *mem;
-
- mem = lang_memory_region_lookup (tree->name.name, FALSE);
- if (mem != NULL)
- new_number (mem->length);
- else
- einfo (_("%F%S: undefined MEMORY region `%s'"
- " referenced in expression\n"),
- tree, tree->name.name);
- }
+ {
+ lang_memory_region_type *mem;
+
+ mem = lang_memory_region_lookup (tree->name.name, FALSE);
+ if (mem != NULL)
+ new_number (mem->length);
+ else
+ einfo (_("%F%S: undefined MEMORY region `%s'"
+ " referenced in expression\n"),
+ tree, tree->name.name);
+ }
}
break;
}
/* Return true if TREE is '.'. */
-
+
static bfd_boolean
is_dot (const etree_type *tree)
{
&& is_dot_ne_0 (tree->trinary.cond)
&& is_value (tree->trinary.rhs, 1));
}
- return 0;
+ return FALSE;
+}
+
+/* Subroutine of exp_fold_tree_1 for copying a symbol type. */
+
+static void
+try_copy_symbol_type (struct bfd_link_hash_entry *h, etree_type *src)
+{
+ struct bfd_link_hash_entry *hsrc;
+
+ hsrc = bfd_link_hash_lookup (link_info.hash, src->name.name,
+ FALSE, FALSE, TRUE);
+ if (hsrc != NULL)
+ bfd_copy_link_hash_symbol_type (link_info.output_bfd, h, hsrc);
}
static void
before relaxation and so be stripped incorrectly. */
if (expld.phase == lang_mark_phase_enum
&& expld.section != bfd_abs_section_ptr
+ && expld.section != bfd_und_section_ptr
&& !(expld.result.valid_p
&& expld.result.value == 0
&& (is_value (tree->assign.src, 0)
|| is_align_conditional (tree->assign.src))))
expld.section->flags |= SEC_KEEP;
- if (!expld.result.valid_p)
+ if (!expld.result.valid_p
+ || expld.section == bfd_und_section_ptr)
{
if (expld.phase != lang_mark_phase_enum)
einfo (_("%F%S invalid assignment to"
if (h == NULL
|| !(h->type == bfd_link_hash_new
|| h->type == bfd_link_hash_undefined
+ || h->type == bfd_link_hash_undefweak
|| h->linker_def))
{
/* Do nothing. The symbol was never referenced, or
- was defined in some object file. Undefined weak
- symbols stay undefined. */
+ was defined in some object file. Note that
+ undefweak symbols are defined by PROVIDE. This
+ is to support glibc use of __rela_iplt_start and
+ similar weak references. */
break;
}
}
h->type = bfd_link_hash_defined;
h->u.def.value = expld.result.value;
h->u.def.section = expld.result.section;
+ h->linker_def = ! tree->assign.type.lineno;
+ h->ldscript_def = 1;
if (tree->type.node_class == etree_provide)
tree->type.node_class = etree_provided;
/* Copy the symbol type if this is a simple assignment of
- one symbol to another. This could be more general
- (e.g. a ?: operator with NAMEs in each branch). */
+ one symbol to another. Also, handle the case of a foldable
+ ternary conditional with names on either side. */
if (tree->assign.src->type.node_class == etree_name)
+ try_copy_symbol_type (h, tree->assign.src);
+ else if (tree->assign.src->type.node_class == etree_trinary)
{
- struct bfd_link_hash_entry *hsrc;
-
- hsrc = bfd_link_hash_lookup (link_info.hash,
- tree->assign.src->name.name,
- FALSE, FALSE, TRUE);
- if (hsrc)
- bfd_copy_link_hash_symbol_type (link_info.output_bfd, h,
- hsrc);
+ exp_fold_tree_1 (tree->assign.src->trinary.cond);
+ if (expld.result.valid_p)
+ {
+ if (expld.result.value
+ && tree->assign.src->trinary.lhs->type.node_class
+ == etree_name)
+ try_copy_symbol_type (h, tree->assign.src->trinary.lhs);
+
+ if (!expld.result.value
+ && tree->assign.src->trinary.rhs->type.node_class
+ == etree_name)
+ try_copy_symbol_type (h, tree->assign.src->trinary.rhs);
+ }
}
}
else if (expld.phase == lang_final_phase_enum)
void
exp_fold_tree (etree_type *tree, asection *current_section, bfd_vma *dotp)
{
+ expld.rel_from_abs = FALSE;
expld.dot = *dotp;
expld.dotp = dotp;
expld.section = current_section;
void
exp_fold_tree_no_dot (etree_type *tree)
{
+ expld.rel_from_abs = FALSE;
expld.dot = 0;
expld.dotp = NULL;
expld.section = bfd_abs_section_ptr;
exp_fold_tree_1 (tree);
}
-etree_type *
-exp_binop (int code, etree_type *lhs, etree_type *rhs)
+static void
+exp_value_fold (etree_type *tree)
{
- etree_type value, *new_e;
-
- value.type.node_code = code;
- value.type.filename = lhs->type.filename;
- value.type.lineno = lhs->type.lineno;
- value.binary.lhs = lhs;
- value.binary.rhs = rhs;
- value.type.node_class = etree_binary;
- exp_fold_tree_no_dot (&value);
+ exp_fold_tree_no_dot (tree);
if (expld.result.valid_p)
- return exp_intop (expld.result.value);
+ {
+ tree->type.node_code = INT;
+ tree->value.value = expld.result.value;
+ tree->value.str = NULL;
+ tree->type.node_class = etree_value;
+ }
+}
+
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
- new_e = (etree_type *) stat_alloc (sizeof (new_e->binary));
- memcpy (new_e, &value, sizeof (new_e->binary));
+etree_type *
+exp_binop (int code, etree_type *lhs, etree_type *rhs)
+{
+ etree_type *new_e = (etree_type *) stat_alloc (MAX (sizeof (new_e->binary),
+ sizeof (new_e->value)));
+ new_e->type.node_code = code;
+ new_e->type.filename = lhs->type.filename;
+ new_e->type.lineno = lhs->type.lineno;
+ new_e->binary.lhs = lhs;
+ new_e->binary.rhs = rhs;
+ new_e->type.node_class = etree_binary;
+ if (lhs->type.node_class == etree_value
+ && rhs->type.node_class == etree_value
+ && code != ALIGN_K
+ && code != DATA_SEGMENT_ALIGN
+ && code != DATA_SEGMENT_RELRO_END)
+ exp_value_fold (new_e);
return new_e;
}
etree_type *
exp_trinop (int code, etree_type *cond, etree_type *lhs, etree_type *rhs)
{
- etree_type value, *new_e;
-
- value.type.node_code = code;
- value.type.filename = cond->type.filename;
- value.type.lineno = cond->type.lineno;
- value.trinary.lhs = lhs;
- value.trinary.cond = cond;
- value.trinary.rhs = rhs;
- value.type.node_class = etree_trinary;
- exp_fold_tree_no_dot (&value);
- if (expld.result.valid_p)
- return exp_intop (expld.result.value);
-
- new_e = (etree_type *) stat_alloc (sizeof (new_e->trinary));
- memcpy (new_e, &value, sizeof (new_e->trinary));
+ etree_type *new_e = (etree_type *) stat_alloc (MAX (sizeof (new_e->trinary),
+ sizeof (new_e->value)));
+ new_e->type.node_code = code;
+ new_e->type.filename = cond->type.filename;
+ new_e->type.lineno = cond->type.lineno;
+ new_e->trinary.lhs = lhs;
+ new_e->trinary.cond = cond;
+ new_e->trinary.rhs = rhs;
+ new_e->type.node_class = etree_trinary;
+ if (cond->type.node_class == etree_value
+ && lhs->type.node_class == etree_value
+ && rhs->type.node_class == etree_value)
+ exp_value_fold (new_e);
return new_e;
}
etree_type *
exp_unop (int code, etree_type *child)
{
- etree_type value, *new_e;
-
- value.unary.type.node_code = code;
- value.unary.type.filename = child->type.filename;
- value.unary.type.lineno = child->type.lineno;
- value.unary.child = child;
- value.unary.type.node_class = etree_unary;
- exp_fold_tree_no_dot (&value);
- if (expld.result.valid_p)
- return exp_intop (expld.result.value);
-
- new_e = (etree_type *) stat_alloc (sizeof (new_e->unary));
- memcpy (new_e, &value, sizeof (new_e->unary));
+ etree_type *new_e = (etree_type *) stat_alloc (MAX (sizeof (new_e->unary),
+ sizeof (new_e->value)));
+ new_e->unary.type.node_code = code;
+ new_e->unary.type.filename = child->type.filename;
+ new_e->unary.type.lineno = child->type.lineno;
+ new_e->unary.child = child;
+ new_e->unary.type.node_class = etree_unary;
+ if (child->type.node_class == etree_value
+ && code != ALIGN_K
+ && code != ABSOLUTE
+ && code != NEXT
+ && code != DATA_SEGMENT_END)
+ exp_value_fold (new_e);
return new_e;
}
etree_type *
exp_nameop (int code, const char *name)
{
- etree_type value, *new_e;
-
- value.name.type.node_code = code;
- value.name.type.filename = ldlex_filename ();
- value.name.type.lineno = lineno;
- value.name.name = name;
- value.name.type.node_class = etree_name;
+ etree_type *new_e = (etree_type *) stat_alloc (sizeof (new_e->name));
- exp_fold_tree_no_dot (&value);
- if (expld.result.valid_p)
- return exp_intop (expld.result.value);
-
- new_e = (etree_type *) stat_alloc (sizeof (new_e->name));
- memcpy (new_e, &value, sizeof (new_e->name));
+ new_e->name.type.node_code = code;
+ new_e->name.type.filename = ldlex_filename ();
+ new_e->name.type.lineno = lineno;
+ new_e->name.name = name;
+ new_e->name.type.node_class = etree_name;
return new_e;
}
einfo (_("%P%F: can not create hash table: %E\n"));
}
+/* Convert absolute symbols defined by a script from "dot" (also
+ SEGMENT_START or ORIGIN) outside of an output section statement,
+ to section relative. */
+
+static bfd_boolean
+set_sym_sections (struct bfd_hash_entry *bh, void *inf ATTRIBUTE_UNUSED)
+{
+ struct definedness_hash_entry *def = (struct definedness_hash_entry *) bh;
+ if (def->final_sec != bfd_abs_section_ptr)
+ {
+ struct bfd_link_hash_entry *h;
+ h = bfd_link_hash_lookup (link_info.hash, bh->string,
+ FALSE, FALSE, TRUE);
+ if (h != NULL
+ && h->type == bfd_link_hash_defined
+ && h->u.def.section == bfd_abs_section_ptr)
+ {
+ h->u.def.value -= def->final_sec->vma;
+ h->u.def.section = def->final_sec;
+ }
+ }
+ return TRUE;
+}
+
+void
+ldexp_finalize_syms (void)
+{
+ bfd_hash_traverse (&definedness_table, set_sym_sections, NULL);
+}
+
void
ldexp_finish (void)
{
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