The linker tries to put the end of the last section in the relro
segment exactly on a page boundary, because the relro segment itself
must end on a page boundary. If for any reason this can't be done,
padding is inserted. Since the end of the relro segment is typically
between .got and .got.plt, padding effectively increases the size of
the GOT. This isn't nice for targets and code models with limited GOT
addressing.
The problem with the current code is that it doesn't cope very well
with aligned sections in the relro segment. When making .got aligned
to a 256 byte boundary for PowerPC64, I found that often the initial
alignment attempt failed and the fallback attempt to be less than
adequate. This is a particular problem for PowerPC64 since the
distance between .got and .plt affects the size of plt call stubs,
leading to "stubs don't match calculated size" errors.
So this rewrite takes a direct approach to calculating a new relro
base. Starting from the last section in the segment, we calculate
where it must start to position its end on the boundary, or as near as
possible considering alignment requirements. The new start then
becomes the goal for the previous section to end, and so on for all
sections. This of course ignores the possibility that user scripts
will place . = ALIGN(xxx); in the relro segment, or provide section
address expressions. In those cases we might fail, but the old code
probably did too, and a fallback is provided.
ld/
* ldexp.h (struct ldexp_control): Delete dataseg.min_base. Add
data_seg.relro_offset.
* ldexp.c (fold_binary <DATA_SEGMENT_ALIGN>): Don't set min_base.
(fold_binary <DATA_SEGMENT_RELRO_END>): Do set relro_offset.
* ldlang.c (lang_size_sections): Rewrite code adjusting relro
segment base to line up last section on page boundary.
ld/testsuite/
* ld-x86-64/pr18176.d: Update.
Adjusting the start of the relro segment in order to make it end
exactly on a page boundary runs into difficulties when sections in the
relro segment are aligned; Adjusting the start by (next_page - end)
sometimes results in more than that adjustment occurring at the end,
overrunning the page boundary. So when that occurs we try a new lower
start position by masking the adjusted start with the maximum section
alignment. However, we didn't consider that this masked start address
may in fact be before the initial relro base, which is silly since
that can only increase padding at the relro end.
I've also moved some calculations closer to where they are used, and
comments closer to the relevant statements.
* ldlang.c (lang_size_sections): When alignment of sections
results in relro base adjustment being too large, don't go lower
than the initial value.
* ldexp.c (fold_binary <DATA_SEGMENT_RELRO_END>): Comment.
* scripttempl/elf.sc (DATA_SEGMENT_ALIGN): Omit SEGMENT_SIZE
alignment when SEGMENT_SIZE is the same as MAXPAGESIZE.
This patch fixes PR 4643 by allowing symbols in the LENGTH and ORIGIN
fields of MEMORY regions. Previously, only constants and constant
expressions are allowed.
For the AVR target, this helps define memory constraints more
accurately (per device), without having to create a ton of device
specific linker scripts.
ld/
PR 4643
* ldexp.c (fold_name): Fold LENGTH only after
lang_first_phase_enum.
* ldgram.y (memory_spec): Don't evaluate ORIGIN and LENGTH
rightaway.
* ldlang.h (struct memory_region_struct): Add origin_exp and
length_exp fields.
* ldlang.c (lang_do_memory_regions): New.
(lang_memory_region_lookup): Initialize origin_exp and
length_exp fields.
(lang_process): Call lang_do_memory_regions.
ld/testsuite/
* ld-scripts/memory.t: Define new symbol tred.
* ld-scripts/memory_sym.t: New.
* ld-scripts/script.exp: Perform MEMORY with symbols test, and
conditionally check values of linker symbols.
or maybe not just yet, but this is better than a FIXME.
* ldexp.c (update_definedness): Return false if script symbol is
redefining a strong symbol in an object.
(exp_fold_tree_1 <etree_assign>): Set up for reporting a multiple
definition error, but for now leave disabled.
Trying to use the SEC_LINKER_CREATED section flag to determine whether
a symbol is linker defined fails to work on targets like alpha that
define special SEC_COMMON sections. These might contain symbols that
originated in an object file.
include/
* bfdlink.h (struct bfd_link_hash_entry): Comment non_ir_ref. Add
linker_def.
bfd/
* elflink.c (_bfd_elf_define_linkage_sym): Set linker_def.
* linker.c (_bfd_generic_link_add_one_symbol): Clear linker_def
for CDEF, DEF, DEFW, COM.
ld/
* ldexp.c (exp_fold_tree_1 <etree_provide>): Test linker_def.
ld/testsuite/
* ld-powerpc/sdabase.s,
* ld-powerpc/sdabase.t,
* ld-powerpc/sdabase.d: New test.
* ld-powerpc/sdabase2.t,
* ld-powerpc/sdabase2.d: New test.
* ld-powerpc/powerpc.exp: Run them.
The old code missed testing bfd_link_hash_undefweak, and wrongly
excluded bfd_link_hash_common symbols. It is also clearer to invert
the set of enum bfd_link_hash_type values tested.
bfd_link_hash_indirect and bfd_link_hash_warning will never appear
here.
* ldexp.c (update_definedness): Correct logic setting by_object.
This moves support code for DEFINED to ldexp.c where it is used,
losing the lang_ prefix on identifiers. Two new functions are needed
to initialize and clean up to hash table, but other than that there
are no functional changes here.
* ldexp.c (struct definedness_hash_entry, definedness_table)
(definedness_newfunc, symbol_defined, update_definedness): Move
and rename from..
* ldlang.h (struct lang_definedness_hash_entry): ..here,..
* ldlang.c (lang_definedness_table, lang_definedness_newfunc)
(lang_symbol_defined, lang_update_definedness): ..and here.
* ldexp.c (ldexp_init, ldexp_finish): New functions, extracted from..
* ldlang.c (lang_init, lang_finish): ..here.
* ldexp.h (ldexp_init, ldexp_finish): Declare.
* ldlang.h (lang_symbol_defined, lang_update_definedness): Delete.
* ldmain.c (main): Call ldexp_init and ldexp_finish.
An assignment to dot in an output section that allocates space of
course keeps the output section. Here, I'm changing the behaviour for
assignments that don't allocate space. The idea is not so much to
allow people to force output of an empty section with ". = .", but
to fix cases where an otherwise empty section has padding added by an
alignment expression that changes with relaxation or .eh_frame
editing. Such a section might have zero size before relaxation and so
be stripped incorrectly.
ld/
* ld.texinfo (Output Section Discarding): Mention assigning to dot
as a way of keeping otherwise empty sections.
* ldexp.c (is_dot, is_value, is_sym_value, is_dot_ne_0,
is_dot_plus_0, is_align_conditional): New predicates.
(exp_fold_tree_1): Set SEC_KEEP when assigning to dot inside an
output section, except for some special cases.
* scripttempl/elfmicroblaze.sc: Use canonical form to align at
end of .heap and .stack.
ld/testsuite/
* ld-shared/elf-offset.ld: Align end of .bss with canonical form
of ALIGN that allows an empty .bss to be removed.
* ld-arm/arm-dyn.ld: Likewise.
* ld-arm/arm-lib.ld: Likewise.
* ld-elfvsb/elf-offset.ld: Likewise.
* ld-mips-elf/mips-dyn.ld: Likewise.
* ld-mips-elf/mips-lib.ld: Likewise.
* ld-arm/arm-no-rel-plt.ld: Remove duplicate ALIGN.
* ld-powerpc/vle-multiseg-1.ld: Remove ALIGN at start of section.
ALIGN address of section instead.
* ld-powerpc/vle-multiseg-2.ld: Likewise.
* ld-powerpc/vle-multiseg-3.ld: Likewise.
* ld-powerpc/vle-multiseg-4.ld: Likewise.
* ld-powerpc/vle-multiseg-6.ld: Likewise.
* ld-scripts/empty-aligned.d: Check section headers not program
headers. Remove xfail and notarget.
* ld-scripts/empty-aligned.t: Use canonical ALIGN for end of .text2.
Modifies ld machinery tracking linker script assignments to notice all
assignments, not just those symbols mentioned in DEFINED().
ld/
PR ld/14962
* ldlang.h (struct lang_definedness_hash_entry): Add by_object and
by_script. Make iteration a single bit field.
(lang_track_definedness, lang_symbol_definition_iteration): Delete.
(lang_symbol_defined): Declare.
* ldlang.c (lang_statement_iteration): Expand comment a little.
(lang_init <lang_definedness_table>): Make it bigger.
(lang_track_definedness, lang_symbol_definition): Delete.
(lang_definedness_newfunc): Update.
(lang_symbol_defined): New function.
(lang_update_definedness): Create entries here. Do track whether
script definition of symbol is valid, even when also defined in
an object file.
* ldexp.c (fold_name <DEFINED>): Update.
(fold_name <NAME>): Allow self-assignment for absolute symbols
defined in a linker script.
ld/testsuite/
* ld-scripts/pr14962-2.d,
* ld-scripts/pr14962-2.t: New test.
* ld-scripts/expr.exp: Run it.
* ldgram.y: Likewise
* ldlex.l: Likewise
* NEWS: Mention the new feature.
* ld.texinfo: Document the new feature.
* ld-scripts/log2.exp: New: Run the new log2 test.
* ld-scripts/log2.s: Source for the new test.
* ld-scripts/log2.t: Linker script for new test.
* ldexp.h (struct ldexp_control): Add "assign_name".
* ldexp.c (fold_name <NAME>): Compare and clear assign_name on match.
(exp_fold_tree_1): Remove existing code testing for self assignment.
Instead set and test expld.assign_name.
* ldlang.c (scan_for_self_assignment): Delete.
(print_assignment): Instead set and test expld.assign_name.
* ldexp.c (fold_name): Ignore undefined symbols when assigning to
dot in mark phase.
(exp_fold_tree_1): Evaluate assignment to dot expressions even when
discarding result, for side effects. Fix typo in error message.
* ldlang.c (lang_process): Rerun lang_do_assignments before
starting garbage collection.
* ldexp.c (fold_name): Generate a reloc for defined symbols
found without an associated output section during the mark phase.
(exp_fold_tree_1): Continue processing an expression, even if we
are unable to fold it, if we are in the first two evaluation
phases.
* ldexp.h (enum lang_phase_type): Add descriptions of the phases.
* ld-gc/pr13683.c: New test source file.
* ld-gc/pr13683.d: New test control and output file.
* ld-gc/gc.exp: Run the pr13683 test.
* ld-cris/tls-gc-68: Update expected symbol table dump.
* ld-cris/tls-gc-69: Likewise.
* ld-cris/tls-gc-70: Likewise.
* ld-cris/tls-gc-71: Likewise.
* ld-cris/tls-gc-75: Likewise.
* ld-cris/tls-gc-76.d: Likewise.
* ld-cris/tls-gc-79.d: Likewise.
* ld.h (parsing_defsym): Delete.
* ldexp.c (exp_intop, exp_bigintop, exp_relop): Set type.filename.
(fold_binary, fold_name, exp_fold_tree_1, exp_get_vma, exp_get_fill,
exp_get_abs_int): Add tree arg for %S in error messages. Don't
fudge lineno.
(exp_binop, exp_unop, exp_nameop, exp_assop, exp_assert): Copy
type.filename from sub-tree.
(exp_trinop): Likewise, and use "cond" rather than "lhs".
* ldexp.h (node_type): Add filename field to struct.
* ldfile.c (ldfile_input_filename): Delete. Remove all refs.
* ldfile.h (ldfile_input_filename): Delete.
* ldgram.y (phdr_type, phdr_qualifiers, yyerror): Add NULL arg for
%S in error messages.
* ldemul.c (syslib_default, hll_default): Likewise.
* ldlang.c (lang_memory_region_lookup, lang_memory_region_alias,
lang_get_regions, lang_new_phdr): Likewise.
(lang_size_sections_1): Pass addr_tree for %S.
* ldlex.h (lex_redirect): Update prototype.
(ldlex_filename): Declare.
* ldlex.l (<EOF>): Don't set ldfile_input_filename.
(lex_redirect): Add fake_filename and count params. Push
fake_filename to file_name_stack and init lineno from count.
(ldlex_filename): New function.
(lex_warn_invalid): Use above.
* ldmain.c (main): Update lex_redirect call.
* ldmisc.c (vfinfo <%S>): Take file name and line number from
etree_type arg, or use current if arg is NULL.
* lexsup.c (parsing_defsym): Delete.
(parse_args <OPTION_DEFSYM>): Update lex_redirect call.
* ldexp.h (enum phase_enum): Comment. Add exp_dataseg_done.
* ldexp.c (fold_unary <DATA_SEGMENT_END>): Rearrange code. Test
for exp_dataseg_done rather than expld.phase == lang_final_phase_enum
to detect when we've finished sizing sections.
(fold_binary <DATA_SEGMENT_ALIGN>): Likewise.
(fold_binary <DATA_SEGMENT_RELRO_END>): Likewise. Also test
that we are not inside an output section statement.
* ldlang.c (lang_size_sections): Set exp_dataseg_done on exit if
not exp_dataseg_relro_adjust or exp_dataseg_adjust. Don't set
lang_final_phase_enum here.
(lang_process): Set lang_final_phase_enum here.
* NEWS: Mention change in linker script expression evaluation.
ld/
* ld.texinfo (Expression Section): Detail expression evaluation.
(Builtin Functions <ADDR>): Correct.
(Builtin Functions <LOADADDR>): Don't mention LOADADDR normally
the same as ADDR.
(Builtin Functions <SEGMENT_START>): Typo fix.
* ldexp.c (new_number): New function.
(make_abs, exp_get_abs_int): Cope with NULL expld.result.section.
(fold_unary <'~', '!', '-'>): Don't make_abs.
(fold_binary): Simplify result section logic. Return NULL section
for logical ops.
(fold_binary <SEGMENT_START>): Use new_rel_from_abs to set value to
a consistent result.
(fold_name <SIZEOF_HEADERS>): Return new_number, not new_abs.
(fold_name <DEFINED, SIZEOF, ALIGNOF, LENGTH, CONSTANT>): Likewise.
(fold_name <NAME>): No need to handle absolute symbols differently
from relative ones.
(fold_name <ORIGIN>): Don't return valid result when
lang_first_phase_enum. Return new_rel_from_abs, not new_abs.
(exp_fold_tree_1 <etree_value>): Return new_number, not new_rel.
(exp_fold_tree_1): Ajust for NULL expld.result.section. When assigning
a plain number to dot, assume the value is relative to expld.section.
Make terms not in an output section, absolute.
* ldlang.c (print_assignment): Fix style nit.
(lang_size_sections_1): Cope with NULL expld.result.section.
(lang_do_assignments_1): Likewise.
ld/testsuite/
* ld-scripts/memory.t: Remove ORIGIN fudge.
keyword in c++.
* bfd/aoutx.h (NAME (aout, make_empty_symbol)): Rename variable
new to new_symbol.
* bfd/coffgen.c (coff_make_empty_symbol)
(coff_bfd_make_debug_symbol): Rename variable new to new_symbol.
* bfd/cpu-ia64-opc.c (ext_reg, ins_imms_scaled): Rename variable
new to new_insn.
* bfd/doc/chew.c (newentry, add_intrinsic): Rename variable new to
new_d.
* bfd/ecoff.c (_bfd_ecoff_make_empty_symbol): Rename variable new
to new_symbol.
* bfd/elf32-m68k.c (elf_m68k_get_got_entry_type): Rename argument
new to new_reloc.
* bfd/hash.c (bfd_hash_lookup): Rename variable new to new_string.
* bfd/ieee.c (ieee_make_empty_symbol): Rename variable new to
new_symbol.
* bfd/linker.c (bfd_new_link_order): Rename variable new to
new_lo.
* bfd/mach-o.c (bfd_mach_o_sizeof_headers): Rename variable new to
symbol.
* bfd/oasys.c (oasys_make_empty_symbol): Rename variable new to
new_symbol_type.
* bfd/pdp11.c (NAME (aout, make_empty_symbol)): Rename variable
new to new_symbol_type.
* bfd/plugin.c (bfd_plugin_make_empty_symbol): Rename variable new
to new_symbol.
* bfd/rs6000-core.c (CoreHdr, VmInfo): Rename union member new to
new_dump.
(read_hdr, rs6000coff_core_p)
(rs6000coff_core_file_matches_executable_p)
(rs6000coff_core_file_failing_command)
(rs6000coff_core_file_failing_signal): Updated function to use new
union member name.
* bfd/som.c (som_make_empty_symbol): Rename variable new to
new_symbol_type.
* bfd/syms.c (_bfd_generic_make_empty_symbol): Rename variable new
to new_symbol.
* bfd/tekhex.c (first_phase, tekhex_make_empty_symbol): Rename
variable new to new_symbol.
* binutils/nlmconv.c (main): Rename variable new to new_name.
* gas/config/tc-arm.c (insert_reg_alias): Rename variable new to
new_reg.
* gas/config/tc-dlx.c (parse_operand): Rename variable new to
new_pos.
* gas/config/tc-ia64.c (ia64_gen_real_reloc_type): Rename variable
new to newr.
* gas/config/tc-mcore.c (parse_exp, parse_imm): Rename variable
new to new_pointer.
* gas/config/tc-microblaze.c (parse_exp, parse_imm, check_got):
Change name from new to new_pointer.
* gas/config/tc-or32.c (parse_operand): Rename variable new to
new_pointer.
* gas/config/tc-pdp11.c (md_assemble): Rename variable new to
new_pointer.
* gas/config/tc-pj.c (alias): Change argument new to new_name.
* gas/config/tc-score.c (s3_build_score_ops_hsh): Rename variable
new to new_opcode. (s3_build_dependency_insn_hsh) Rename variable
new to new_i2n. (s3_convert): Rename variables old and new to
r_old and r_new.
* gas/config/tc-score7.c (s7_build_score_ops_hsh): Rename variable
new to new_opcode. (s7_build_dependency_insn_hsh): Rename variable
new to new_i2d. (s7_b32_relax_to_b16, s7_convert_frag): Rename
variables old and new to r_old and r_new.
* gas/config/tc-sh.c (parse_exp): Rename variable new to
new_pointer.
* gas/config/tc-sh64.c (shmedia_parse_exp): Rename variable new to
new_pointer.
* gas/config/tc-tic4x.c (tic4x_operand_parse): Rename variable new
to new_pointer.
* gas/config/tc-z8k.c (parse_exp): Rename variable new to
new_pointer.
* gas/listing.c (listing_newline): Rename variable new to new_i.
* ld/ldexp.c (exp_intop, exp_bigintop, exp_relop, exp_binop)
(exp_trinop, exp_unop, exp_nameop, exp_assop): Rename variable new
to new_e.
* ld/ldfile.c (ldfile_add_library_path): Rename variable new to
new_dirs. (ldfile_add_arch): Rename variable new to new_arch.
* ld/ldlang.c (new_statement, lang_final, lang_add_wild)
(lang_target, lang_add_fill, lang_add_data, lang_add_assignment)
(lang_add_insert): Rename variable new to new_stmt. (new_afile):
Added missing cast. (lang_memory_region_lookup): Rename variable
new to new_region. (init_os): Rename variable new to
new_userdata. (lang_add_section): Rename variable new to
new_section. (ldlang_add_undef): Rename variable new to
new_undef. (realsymbol): Rename variable new to new_name.
* opcodes/z8kgen.c (internal, gas): Rename variable new to new_op.
Updated sources to avoid using the identifier name "template",
which is a keyword in c++.
* bfd/elf32-arm.c (struct stub_def): Rename member template to
template_sequence. (arm_build_one_stub,
find_stub_size_and_template, arm_size_one_stub, arm_map_one_stub):
Rename variable template to template_sequence.
* bfd/elfxx-ia64.c (elfNN_ia64_relax_br, elfNN_ia64_relax_brl):
Rename variable template to template_val.
* gas/config/tc-arm.c (struct asm_cond, struct asm_psr, struct
asm_barrier_opt): Change member template to
template_name. (md_begin): Update code to reflect new member
names.
* gas/config/tc-i386.c (struct templates, struct _i386_insn)
(match_template, cpu_flags_match, match_reg_size, match_mem_size)
(operand_size_match, md_begin, i386_print_statistics, pi)
(build_vex_prefix, md_assemble, parse_insn, optimize_imm)
(optimize_disp): Updated code to use new names. (parse_insn):
Added casts.
* gas/config/tc-ia64.c (dot_template, emit_one_bundle): Updated
code to use new names.
* gas/config/tc-score.c (struct s3_asm_opcode): Renamed member
template to template_name. (s3_parse_16_32_inst, s3_parse_48_inst,
s3_do_macro_ldst_label, s3_build_score_ops_hsh): Update code to
use new names.
* gas/config/tc-score7.c (struct s7_asm_opcode): Renamed member
template to template_name. (s7_parse_16_32_inst,
s7_do_macro_ldst_label, s7_build_score_ops_hsh): Update code to
use new names.
* gas/config/tc-tic30.c (md_begin, struct tic30_insn)
(md_assemble): Update code to use new names.
* gas/config/tc-tic54x.c (struct _tic54x_insn, md_begin)
(optimize_insn, tic54x_parse_insn, next_line_shows_parallel):
Update code to use new names.
* include/opcode/tic30.h (template): Rename type template to
insn_template. Updated code to use new name.
* include/opcode/tic54x.h (template): Rename type template to
insn_template.
* opcodes/cris-dis.c (bytes_to_skip): Update code to use new name.
* opcodes/i386-dis.c (putop): Update code to use new name.
* opcodes/i386-gen.c (process_i386_opcodes): Update code to use
new name.
* opcodes/i386-opc.h (struct template): Rename struct template to
insn_template. Update code accordingly.
* opcodes/i386-tbl.h (i386_optab): Update type to use new name.
* opcodes/ia64-dis.c (print_insn_ia64): Rename variable template
to template_val.
* opcodes/tic30-dis.c (struct instruction, get_tic30_instruction):
Update code to use new name.
* opcodes/tic54x-dis.c (has_lkaddr, get_insn_size)
(print_parallel_instruction, print_insn_tic54x, tic54x_get_insn):
Update code to use new name.
* opcodes/tic54x-opc.c (tic54x_unknown_opcode, tic54x_optab):
Update type to new name.
* ldexp.c (fold_binary <DATA_SEGMENT_ALIGN>): Do not align
EXPLD.DATASEG.MIN_BASE.
* ldlang.c (lang_size_sections): New variable OLD_BASE. Rename
OLD_MIN_BASE to MIN_BASE with the former alignment from `ldexp.c'.
Use OLD_BASE now for the minimal base check after the base decrease by
the maximum alignment found.
MAX_K.
(fold_binary <SEGMENT_START>): Set expld.result.section to
current section. Expand comment. Formatting.
(fold_name <DEFINED>): Set expld.result.section to current section.
Alan Modra