X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=ld%2Fldexp.c;h=ac66cc02aef23556cf6b3d8b8c104498a4026d21;hb=7e993ebf2343a5b39d6d1df29fdebc2818064ae5;hp=59743ea1ec9d2fbd30070b27da6919c576de5e05;hpb=67baf8c476074caad96ac5ed7ff990904e5678de;p=deliverable%2Fbinutils-gdb.git diff --git a/ld/ldexp.c b/ld/ldexp.c index 59743ea1ec..ac66cc02ae 100644 --- a/ld/ldexp.c +++ b/ld/ldexp.c @@ -1,7 +1,5 @@ /* This module handles expression trees. - Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, - 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 - Free Software Foundation, Inc. + Copyright (C) 1991-2015 Free Software Foundation, Inc. Written by Steve Chamberlain of Cygnus Support . This file is part of the GNU Binutils. @@ -50,6 +48,19 @@ segment_type *segments; struct ldexp_control expld; +/* This structure records symbols for which we need to keep track of + definedness for use in the DEFINED () test. */ + +struct definedness_hash_entry +{ + struct bfd_hash_entry root; + unsigned int by_object : 1; + unsigned int by_script : 1; + unsigned int iteration : 1; +}; + +static struct bfd_hash_table definedness_table; + /* Print the string representation of the given token. Surround it with spaces if INFIX_P is TRUE. */ @@ -81,6 +92,7 @@ exp_print_token (token_code_type code, int infix_p) { GE, ">=" }, { LSHIFT, "<<" }, { RSHIFT, ">>" }, + { LOG2CEIL, "LOG2CEIL" }, { ALIGN_K, "ALIGN" }, { BLOCK, "BLOCK" }, { QUAD, "QUAD" }, @@ -134,6 +146,28 @@ exp_print_token (token_code_type code, int infix_p) fputc (' ', config.map_file); } +static void +make_log2ceil (void) +{ + bfd_vma value = expld.result.value; + bfd_vma result = -1; + bfd_boolean round_up = FALSE; + + do + { + result++; + /* If more than one bit is set in the value we will need to round up. */ + if ((value > 1) && (value & 1)) + round_up = TRUE; + } + while (value >>= 1); + + if (round_up) + result += 1; + expld.result.section = NULL; + expld.result.value = result; +} + static void make_abs (void) { @@ -213,10 +247,82 @@ new_rel (bfd_vma value, asection *section) static void new_rel_from_abs (bfd_vma value) { + asection *s = expld.section; + + if (s == bfd_abs_section_ptr && expld.phase == lang_final_phase_enum) + s = section_for_dot (); expld.result.valid_p = TRUE; - expld.result.value = value - expld.section->vma; + expld.result.value = value - s->vma; expld.result.str = NULL; - expld.result.section = expld.section; + expld.result.section = s; +} + +/* New-function for the definedness hash table. */ + +static struct bfd_hash_entry * +definedness_newfunc (struct bfd_hash_entry *entry, + struct bfd_hash_table *table ATTRIBUTE_UNUSED, + const char *name ATTRIBUTE_UNUSED) +{ + struct definedness_hash_entry *ret = (struct definedness_hash_entry *) entry; + + if (ret == NULL) + ret = (struct definedness_hash_entry *) + bfd_hash_allocate (table, sizeof (struct definedness_hash_entry)); + + if (ret == NULL) + einfo (_("%P%F: bfd_hash_allocate failed creating symbol %s\n"), name); + + ret->by_object = 0; + ret->by_script = 0; + ret->iteration = 0; + return &ret->root; +} + +/* Called during processing of linker script script expressions. + For symbols assigned in a linker script, return a struct describing + where the symbol is defined relative to the current expression, + otherwise return NULL. */ + +static struct definedness_hash_entry * +symbol_defined (const char *name) +{ + return ((struct definedness_hash_entry *) + bfd_hash_lookup (&definedness_table, name, FALSE, FALSE)); +} + +/* Update the definedness state of NAME. Return FALSE if script symbol + is multiply defining a strong symbol in an object. */ + +static bfd_boolean +update_definedness (const char *name, struct bfd_link_hash_entry *h) +{ + bfd_boolean ret; + struct definedness_hash_entry *defentry + = (struct definedness_hash_entry *) + bfd_hash_lookup (&definedness_table, name, TRUE, FALSE); + + if (defentry == NULL) + einfo (_("%P%F: bfd_hash_lookup failed creating symbol %s\n"), name); + + /* If the symbol was already defined, and not by a script, then it + must be defined by an object file or by the linker target code. */ + ret = TRUE; + if (!defentry->by_script + && (h->type == bfd_link_hash_defined + || h->type == bfd_link_hash_defweak + || h->type == bfd_link_hash_common)) + { + defentry->by_object = 1; + if (h->type == bfd_link_hash_defined + && h->u.def.section->output_section != NULL + && !h->linker_def) + ret = FALSE; + } + + defentry->by_script = 1; + defentry->iteration = lang_statement_iteration; + return ret; } static void @@ -238,6 +344,10 @@ fold_unary (etree_type *tree) make_abs (); break; + case LOG2CEIL: + make_log2ceil (); + break; + case '~': expld.result.value = ~expld.result.value; break; @@ -308,7 +418,7 @@ fold_binary (etree_type *tree) /* Check to see if the user has overridden the default value. */ segment_name = tree->binary.rhs->name.name; - for (seg = segments; seg; seg = seg->next) + for (seg = segments; seg; seg = seg->next) if (strcmp (seg->name, segment_name) == 0) { if (!seg->used @@ -546,13 +656,10 @@ fold_name (etree_type *tree) break; case DEFINED: - if (expld.phase == lang_first_phase_enum) - lang_track_definedness (tree->name.name); - else + if (expld.phase != lang_first_phase_enum) { struct bfd_link_hash_entry *h; - int def_iteration - = lang_symbol_definition_iteration (tree->name.name); + struct definedness_hash_entry *def; h = bfd_wrapped_link_hash_lookup (link_info.output_bfd, &link_info, @@ -562,12 +669,33 @@ fold_name (etree_type *tree) && (h->type == bfd_link_hash_defined || h->type == bfd_link_hash_defweak || h->type == bfd_link_hash_common) - && (def_iteration == lang_statement_iteration - || def_iteration == -1)); + && ((def = symbol_defined (tree->name.name)) == NULL + || def->by_object + || def->iteration == (lang_statement_iteration & 1))); } break; case NAME: + if (expld.assign_name != NULL + && strcmp (expld.assign_name, tree->name.name) == 0) + { + /* Self-assignment is only allowed for absolute symbols + defined in a linker script. */ + struct bfd_link_hash_entry *h; + struct definedness_hash_entry *def; + + h = bfd_wrapped_link_hash_lookup (link_info.output_bfd, + &link_info, + tree->name.name, + FALSE, FALSE, TRUE); + if (!(h != NULL + && (h->type == bfd_link_hash_defined + || h->type == bfd_link_hash_defweak) + && h->u.def.section == bfd_abs_section_ptr + && (def = symbol_defined (tree->name.name)) != NULL + && def->iteration == (lang_statement_iteration & 1))) + expld.assign_name = NULL; + } if (expld.phase == lang_first_phase_enum) ; else if (tree->name.name[0] == '.' && tree->name.name[1] == 0) @@ -606,7 +734,8 @@ fold_name (etree_type *tree) output_section); } else if (expld.phase == lang_final_phase_enum - || expld.assigning_to_dot) + || (expld.phase != lang_mark_phase_enum + && expld.assigning_to_dot)) einfo (_("%F%S: undefined symbol `%s'" " referenced in expression\n"), tree, tree->name.name); @@ -680,7 +809,7 @@ fold_name (etree_type *tree) tree, tree->name.name); new_number (0); } - else if (os->processed_vma) + else if (os->bfd_section != NULL) { bfd_vma val; @@ -689,23 +818,28 @@ fold_name (etree_type *tree) / bfd_octets_per_byte (link_info.output_bfd)); else val = (bfd_vma)1 << os->bfd_section->alignment_power; - + new_number (val); } + else + new_number (0); } break; case LENGTH: { - 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); + 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); + } } break; @@ -713,11 +847,11 @@ fold_name (etree_type *tree) if (expld.phase != lang_first_phase_enum) { lang_memory_region_type *mem; - - mem = lang_memory_region_lookup (tree->name.name, FALSE); - if (mem != NULL) + + mem = lang_memory_region_lookup (tree->name.name, FALSE); + if (mem != NULL) new_rel_from_abs (mem->origin); - else + else einfo (_("%F%S: undefined MEMORY region `%s'" " referenced in expression\n"), tree, tree->name.name); @@ -740,6 +874,89 @@ 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 definedness_hash_entry *def; + + return (tree->type.node_class == etree_name + && tree->type.node_code == NAME + && (def = 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) { @@ -797,20 +1014,27 @@ exp_fold_tree_1 (etree_type *tree) if (tree->type.node_class != etree_assign) einfo (_("%F%S can not PROVIDE assignment to" " location counter\n"), tree); - /* After allocation, assignment to dot should not be done inside - an output section since allocation adds a padding statement - that effectively duplicates the assignment. */ - if (expld.phase == lang_mark_phase_enum - || expld.phase == lang_allocating_phase_enum - || ((expld.phase == lang_assigning_phase_enum - || expld.phase == lang_final_phase_enum) - && expld.section == bfd_abs_section_ptr)) + if (expld.phase != lang_first_phase_enum) { /* Notify the folder that this is an assignment to dot. */ expld.assigning_to_dot = TRUE; 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) @@ -819,8 +1043,14 @@ exp_fold_tree_1 (etree_type *tree) } else if (expld.dotp == NULL) einfo (_("%F%S assignment to location counter" - " invalid outside of SECTION\n"), tree); - else + " invalid outside of SECTIONS\n"), tree); + + /* After allocation, assignment to dot should not be + done inside an output section since allocation adds a + padding statement that effectively duplicates the + assignment. */ + else if (expld.phase <= lang_allocating_phase_enum + || expld.section == bfd_abs_section_ptr) { bfd_vma nextdot; @@ -846,8 +1076,6 @@ exp_fold_tree_1 (etree_type *tree) } else { - etree_type *name; - struct bfd_link_hash_entry *h = NULL; if (tree->type.node_class == etree_provide) @@ -855,38 +1083,34 @@ exp_fold_tree_1 (etree_type *tree) h = bfd_link_hash_lookup (link_info.hash, tree->assign.dst, FALSE, FALSE, TRUE); if (h == NULL - || (h->type != bfd_link_hash_new - && h->type != bfd_link_hash_undefined - && h->type != bfd_link_hash_common)) + || !(h->type == bfd_link_hash_new + || h->type == bfd_link_hash_undefined + || h->linker_def)) { - /* Do nothing. The symbol was never referenced, or was - defined by some object. */ + /* Do nothing. The symbol was never referenced, or + was defined in some object file. Undefined weak + symbols stay undefined. */ break; } } - name = tree->assign.src; - if (name->type.node_class == etree_trinary) - { - exp_fold_tree_1 (name->trinary.cond); - if (expld.result.valid_p) - name = (expld.result.value - ? name->trinary.lhs : name->trinary.rhs); - } - - if (name->type.node_class == etree_name - && name->type.node_code == NAME - && strcmp (tree->assign.dst, name->name.name) == 0) - /* Leave it alone. Do not replace a symbol with its own - output address, in case there is another section sizing - pass. Folding does not preserve input sections. */ - break; - + expld.assign_name = tree->assign.dst; exp_fold_tree_1 (tree->assign.src); - if (expld.result.valid_p + /* expld.assign_name remaining equal to tree->assign.dst + below indicates the evaluation of tree->assign.src did + not use the value of tree->assign.dst. We don't allow + self assignment until the final phase for two reasons: + 1) Expressions are evaluated multiple times. With + relaxation, the number of times may vary. + 2) Section relative symbol values cannot be correctly + converted to absolute values, as is required by many + expressions, until final section sizing is complete. */ + if ((expld.result.valid_p + && (expld.phase == lang_final_phase_enum + || expld.assign_name != NULL)) || (expld.phase <= lang_mark_phase_enum && tree->type.node_class == etree_assign - && tree->assign.hidden)) + && tree->assign.defsym)) { if (h == NULL) { @@ -897,19 +1121,27 @@ exp_fold_tree_1 (etree_type *tree) tree->assign.dst); } - /* FIXME: Should we worry if the symbol is already - defined? */ - lang_update_definedness (tree->assign.dst, h); - h->type = bfd_link_hash_defined; - h->u.def.value = expld.result.value; if (expld.result.section == NULL) expld.result.section = expld.section; + if (!update_definedness (tree->assign.dst, h) && 0) + { + /* Symbol was already defined. For now this error + is disabled because it causes failures in the ld + testsuite: ld-elf/var1, ld-scripts/defined5, and + ld-scripts/pr14962. Some of these no doubt + reflect scripts used in the wild. */ + (*link_info.callbacks->multiple_definition) + (&link_info, h, link_info.output_bfd, + expld.result.section, expld.result.value); + } + h->type = bfd_link_hash_defined; + h->u.def.value = expld.result.value; h->u.def.section = expld.result.section; 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 + one symbol to another. This could be more general (e.g. a ?: operator with NAMEs in each branch). */ if (tree->assign.src->type.node_class == etree_name) { @@ -931,6 +1163,7 @@ exp_fold_tree_1 (etree_type *tree) && h->type == bfd_link_hash_new) h->type = bfd_link_hash_undefined; } + expld.assign_name = NULL; } break; @@ -1048,6 +1281,7 @@ static etree_type * exp_assop (const char *dst, etree_type *src, enum node_tree_enum class, + bfd_boolean defsym, bfd_boolean hidden) { etree_type *n; @@ -1059,20 +1293,25 @@ exp_assop (const char *dst, n->assign.type.node_class = class; n->assign.src = src; n->assign.dst = dst; + n->assign.defsym = defsym; n->assign.hidden = hidden; return n; } +/* Handle linker script assignments and HIDDEN. */ + etree_type * -exp_assign (const char *dst, etree_type *src) +exp_assign (const char *dst, etree_type *src, bfd_boolean hidden) { - return exp_assop (dst, src, etree_assign, FALSE); + return exp_assop (dst, src, etree_assign, FALSE, hidden); } +/* Handle --defsym command-line option. */ + etree_type * exp_defsym (const char *dst, etree_type *src) { - return exp_assop (dst, src, etree_assign, TRUE); + return exp_assop (dst, src, etree_assign, TRUE, FALSE); } /* Handle PROVIDE. */ @@ -1080,7 +1319,7 @@ exp_defsym (const char *dst, etree_type *src) etree_type * exp_provide (const char *dst, etree_type *src, bfd_boolean hidden) { - return exp_assop (dst, src, etree_provide, hidden); + return exp_assop (dst, src, etree_provide, FALSE, hidden); } /* Handle ASSERT. */ @@ -1321,3 +1560,21 @@ align_n (bfd_vma value, bfd_vma align) value = (value + align - 1) / align; return value * align; } + +void +ldexp_init (void) +{ + /* The value "13" is ad-hoc, somewhat related to the expected number of + assignments in a linker script. */ + if (!bfd_hash_table_init_n (&definedness_table, + definedness_newfunc, + sizeof (struct definedness_hash_entry), + 13)) + einfo (_("%P%F: can not create hash table: %E\n")); +} + +void +ldexp_finish (void) +{ + bfd_hash_table_free (&definedness_table); +}