[binutils-gdb] bfd/ELF: restrict file alignment for object files
Jan Beulich
jbeulich@sourceware.org
Fri Oct 11 06:21:52 GMT 2024
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=1f1b5e506bf0d9bffef8525eb9bee19646713eb6
commit 1f1b5e506bf0d9bffef8525eb9bee19646713eb6
Author: Jan Beulich <jbeulich@suse.com>
Date: Fri Oct 11 08:19:34 2024 +0200
bfd/ELF: restrict file alignment for object files
While for executables properly aligning sections within the file can be
quite relevant, the same is of pretty little importance for relocatable
object files. Avoid passing "true" into
_bfd_elf_assign_file_position_for_section() when dealing with object
files, but compensate minimally by applying log_file_align in such
cases as a cap to the alignment put in place.
Diff:
---
bfd/elf-bfd.h | 2 +-
bfd/elf.c | 44 +++++++++++++++-------
bfd/elflink.c | 6 +--
.../testsuite/binutils-all/i386/compressed-1b.d | 8 ++--
.../testsuite/binutils-all/i386/compressed-1c.d | 8 ++--
binutils/testsuite/binutils-all/readelf.s | 2 +-
gas/testsuite/gas/aarch64/tail_padding.d | 6 +--
gas/testsuite/gas/arm/ehabi-pacbti-m.d | 2 +-
gas/testsuite/gas/ia64/group-1.d | 10 ++---
gas/testsuite/gas/ia64/group-2.d | 14 +++----
gas/testsuite/gas/mmix/bspec-2.d | 4 +-
ld/testsuite/ld-x86-64/pr27590.rd | 18 ++++-----
12 files changed, 70 insertions(+), 54 deletions(-)
diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index b89d3dda05d..96cf11936ae 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -2540,7 +2540,7 @@ extern long _bfd_elf_link_lookup_local_dynindx
extern bool _bfd_elf_compute_section_file_positions
(bfd *, struct bfd_link_info *);
extern file_ptr _bfd_elf_assign_file_position_for_section
- (Elf_Internal_Shdr *, file_ptr, bool);
+ (Elf_Internal_Shdr *, file_ptr, bool, unsigned char);
extern bool _bfd_elf_modify_headers
(bfd *, struct bfd_link_info *);
diff --git a/bfd/elf.c b/bfd/elf.c
index 997befd5686..27d45fc17a5 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -4572,10 +4572,23 @@ align_file_position (file_ptr off, int align)
file_ptr
_bfd_elf_assign_file_position_for_section (Elf_Internal_Shdr *i_shdrp,
file_ptr offset,
- bool align)
+ bool align,
+ unsigned char log_file_align)
{
- if (align && i_shdrp->sh_addralign > 1)
- offset = BFD_ALIGN (offset, i_shdrp->sh_addralign & -i_shdrp->sh_addralign);
+ if (i_shdrp->sh_addralign > 1)
+ {
+ file_ptr salign = i_shdrp->sh_addralign & -i_shdrp->sh_addralign;
+
+ if (align)
+ offset = BFD_ALIGN (offset, salign);
+ else if (log_file_align)
+ {
+ /* Heuristic: Cap alignment at log_file_align. */
+ file_ptr falign = 1u << log_file_align;
+
+ offset = BFD_ALIGN (offset, salign < falign ? salign : falign);
+ }
+ }
i_shdrp->sh_offset = offset;
if (i_shdrp->bfd_section != NULL)
i_shdrp->bfd_section->filepos = offset;
@@ -4663,18 +4676,18 @@ _bfd_elf_compute_section_file_positions (bfd *abfd,
off = elf_next_file_pos (abfd);
hdr = & elf_symtab_hdr (abfd);
- off = _bfd_elf_assign_file_position_for_section (hdr, off, true);
+ off = _bfd_elf_assign_file_position_for_section (hdr, off, true, 0);
if (elf_symtab_shndx_list (abfd) != NULL)
{
hdr = & elf_symtab_shndx_list (abfd)->hdr;
if (hdr->sh_size != 0)
- off = _bfd_elf_assign_file_position_for_section (hdr, off, true);
+ off = _bfd_elf_assign_file_position_for_section (hdr, off, true, 0);
/* FIXME: What about other symtab_shndx sections in the list ? */
}
hdr = &elf_tdata (abfd)->strtab_hdr;
- off = _bfd_elf_assign_file_position_for_section (hdr, off, true);
+ off = _bfd_elf_assign_file_position_for_section (hdr, off, true, 0);
elf_next_file_pos (abfd) = off;
@@ -6548,8 +6561,8 @@ assign_file_positions_for_non_load_sections (bfd *abfd,
else
align = hdr->sh_addralign & -hdr->sh_addralign;
off += vma_page_aligned_bias (hdr->sh_addr, off, align);
- off = _bfd_elf_assign_file_position_for_section (hdr, off,
- false);
+ off = _bfd_elf_assign_file_position_for_section (hdr, off, false,
+ bed->s->log_file_align);
}
else if (((hdr->sh_type == SHT_REL || hdr->sh_type == SHT_RELA)
&& hdr->bfd_section == NULL)
@@ -6566,7 +6579,7 @@ assign_file_positions_for_non_load_sections (bfd *abfd,
|| hdr == i_shdrpp[elf_shstrtab_sec (abfd)])
hdr->sh_offset = -1;
else
- off = _bfd_elf_assign_file_position_for_section (hdr, off, true);
+ off = _bfd_elf_assign_file_position_for_section (hdr, off, true, 0);
}
elf_next_file_pos (abfd) = off;
@@ -6803,7 +6816,8 @@ assign_file_positions_except_relocs (bfd *abfd,
hdr->sh_offset = -1;
}
else
- off = _bfd_elf_assign_file_position_for_section (hdr, off, true);
+ off = _bfd_elf_assign_file_position_for_section (hdr, off, false,
+ 0);
}
elf_next_file_pos (abfd) = off;
@@ -7018,7 +7032,7 @@ _bfd_elf_assign_file_positions_for_non_load (bfd *abfd)
Elf_Internal_Shdr **shdrpp, **end_shdrpp;
Elf_Internal_Shdr *shdrp;
Elf_Internal_Ehdr *i_ehdrp;
- const struct elf_backend_data *bed;
+ const struct elf_backend_data *bed = get_elf_backend_data (abfd);
/* Skip non-load sections without section header. */
if ((abfd->flags & BFD_NO_SECTION_HEADER) != 0)
@@ -7086,7 +7100,10 @@ _bfd_elf_assign_file_positions_for_non_load (bfd *abfd)
sec->contents = NULL;
}
- off = _bfd_elf_assign_file_position_for_section (shdrp, off, true);
+ off = _bfd_elf_assign_file_position_for_section (shdrp, off,
+ (abfd->flags & (EXEC_P | DYNAMIC))
+ || bfd_get_format (abfd) == bfd_core,
+ bed->s->log_file_align);
}
}
@@ -7095,11 +7112,10 @@ _bfd_elf_assign_file_positions_for_non_load (bfd *abfd)
_bfd_elf_strtab_finalize (elf_shstrtab (abfd));
shdrp = &elf_tdata (abfd)->shstrtab_hdr;
shdrp->sh_size = _bfd_elf_strtab_size (elf_shstrtab (abfd));
- off = _bfd_elf_assign_file_position_for_section (shdrp, off, true);
+ off = _bfd_elf_assign_file_position_for_section (shdrp, off, true, 0);
/* Place the section headers. */
i_ehdrp = elf_elfheader (abfd);
- bed = get_elf_backend_data (abfd);
off = align_file_position (off, 1 << bed->s->log_file_align);
i_ehdrp->e_shoff = off;
off += i_ehdrp->e_shnum * i_ehdrp->e_shentsize;
diff --git a/bfd/elflink.c b/bfd/elflink.c
index a498dbb12a6..19a9aec3f9d 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -12926,7 +12926,7 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
{
file_ptr off = elf_next_file_pos (abfd);
- _bfd_elf_assign_file_position_for_section (symtab_hdr, off, true);
+ _bfd_elf_assign_file_position_for_section (symtab_hdr, off, true, 0);
/* Note that at this point elf_next_file_pos (abfd) is
incorrect. We do not yet know the size of the .symtab section.
@@ -13370,7 +13370,7 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
symtab_shndx_hdr->sh_size = amt;
off = _bfd_elf_assign_file_position_for_section (symtab_shndx_hdr,
- off, true);
+ off, true, 0);
if (bfd_seek (abfd, symtab_shndx_hdr->sh_offset, SEEK_SET) != 0
|| (bfd_write (flinfo.symshndxbuf, amt, abfd) != amt))
@@ -13394,7 +13394,7 @@ bfd_elf_final_link (bfd *abfd, struct bfd_link_info *info)
symstrtab_hdr->sh_addralign = 1;
off = _bfd_elf_assign_file_position_for_section (symstrtab_hdr,
- off, true);
+ off, true, 0);
elf_next_file_pos (abfd) = off;
if (bfd_seek (abfd, symstrtab_hdr->sh_offset, SEEK_SET) != 0
diff --git a/binutils/testsuite/binutils-all/i386/compressed-1b.d b/binutils/testsuite/binutils-all/i386/compressed-1b.d
index 6e45e552fc8..8b3f75ab846 100644
--- a/binutils/testsuite/binutils-all/i386/compressed-1b.d
+++ b/binutils/testsuite/binutils-all/i386/compressed-1b.d
@@ -10,9 +10,9 @@ There are 5 section headers, starting at offset 0x[0-9a-f]+:
Section Headers:
\[Nr\] Name Type Addr Off Size ES Flg Lk Inf Al
\[ 0\] NULL 00000000 000000 000000 00 0 0 0
- \[ 1\] .text PROGBITS 00000000 000040 00001b 00 AX 0 0 16
- \[ 2\] .data PROGBITS 00000000 00005b 000000 00 WA 0 0 1
- \[ 3\] .bss NOBITS 00000000 00005b 000000 00 WA 0 0 1
- \[ 4\] .shstrtab STRTAB 00000000 [0-9a-f]+ 00001c 00 . 0 0 1
+ \[ 1\] .text PROGBITS 00000000 0000.. 00001b 00 AX 0 0 16
+ \[ 2\] .data PROGBITS 00000000 0000.. 000000 00 WA 0 0 1
+ \[ 3\] .bss NOBITS 00000000 0000.. 000000 00 WA 0 0 1
+ \[ 4\] .shstrtab STRTAB 00000000 0000.. 00001c 00 .. 0 0 1
Key to Flags:
#...
diff --git a/binutils/testsuite/binutils-all/i386/compressed-1c.d b/binutils/testsuite/binutils-all/i386/compressed-1c.d
index 1e1a18e7786..f65e8cf2037 100644
--- a/binutils/testsuite/binutils-all/i386/compressed-1c.d
+++ b/binutils/testsuite/binutils-all/i386/compressed-1c.d
@@ -10,9 +10,9 @@ There are 5 section headers, starting at offset 0x[0-9a-f]+:
Section Headers:
\[Nr\] Name Type Addr Off Size ES Flg Lk Inf Al
\[ 0\] NULL 00000000 000000 000000 00 0 0 0
- \[ 1\] .text PROGBITS 00000000 000040 00001b 00 AX 0 0 16
- \[ 2\] .data PROGBITS 00000000 00005b 000000 00 WA 0 0 1
- \[ 3\] .bss NOBITS 00000000 00005b 000000 00 WA 0 0 1
- \[ 4\] .shstrtab STRTAB 00000000 [0-9a-f]+ 00001c 00 .* 0 0 1
+ \[ 1\] .text PROGBITS 00000000 0000.. 00001b 00 AX 0 0 16
+ \[ 2\] .data PROGBITS 00000000 0000.. 000000 00 WA 0 0 1
+ \[ 3\] .bss NOBITS 00000000 0000.. 000000 00 WA 0 0 1
+ \[ 4\] .shstrtab STRTAB 00000000 0000.. 00001c 00 .. 0 0 1
Key to Flags:
#...
diff --git a/binutils/testsuite/binutils-all/readelf.s b/binutils/testsuite/binutils-all/readelf.s
index ff37acb4da8..5a1f320c6e1 100644
--- a/binutils/testsuite/binutils-all/readelf.s
+++ b/binutils/testsuite/binutils-all/readelf.s
@@ -10,7 +10,7 @@ Section Headers:
# MIPS targets put .rela.text here.
#...
+\[ .\] .* +PROGBITS +00000000 0000(3c|40|44|48|50) 0000(04|10) 00 +WA +0 +0 +(.|..)
- +\[ .\] .* +NOBITS +00000000 0000(40|44|48|4c|60) 000000 00 +WA +0 +0 +(.|..)
+ +\[ .\] .* +NOBITS +00000000 0+[0-9a-f]+ 000000 00 +WA +0 +0 +(.|..)
# ARM targets put .ARM.attributes here.
# MIPS targets put .reginfo, .mdebug, .MIPS.abiflags and .gnu.attributes here.
# v850 targets put .call_table_data and .call_table_text here.
diff --git a/gas/testsuite/gas/aarch64/tail_padding.d b/gas/testsuite/gas/aarch64/tail_padding.d
index acb4ff2ff46..12f2f6f06ac 100644
--- a/gas/testsuite/gas/aarch64/tail_padding.d
+++ b/gas/testsuite/gas/aarch64/tail_padding.d
@@ -11,10 +11,10 @@ Section Headers:
Size EntSize Flags Link Info Align
\[ 0\] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
- \[ 1\] \.text PROGBITS 0000000000000000 00000040
+ \[ 1\] \.text PROGBITS 0000000000000000 000000..
0000000000000000 0000000000000000 AX 0 0 1
- \[ 2\] \.data PROGBITS 0000000000000000 00000040
+ \[ 2\] \.data PROGBITS 0000000000000000 000000..
0000000000000008 0000000000000000 WA 0 0 64
- \[ 3\] \.bss NOBITS 0000000000000000 00000080
+ \[ 3\] \.bss NOBITS 0000000000000000 000000..
000000000000000c 0000000000000000 WA 0 0 64
#...
diff --git a/gas/testsuite/gas/arm/ehabi-pacbti-m.d b/gas/testsuite/gas/arm/ehabi-pacbti-m.d
index 1b13020835c..dca7abd5b1a 100644
--- a/gas/testsuite/gas/arm/ehabi-pacbti-m.d
+++ b/gas/testsuite/gas/arm/ehabi-pacbti-m.d
@@ -4,7 +4,7 @@
#readelf: -u
#target: [is_elf_format]
-Unwind section '.ARM.exidx' at offset 0x5c contains 1 entry:
+Unwind section '.ARM.exidx' at offset 0x[0-9a-f]+ contains 1 entry:
0x0: @0x0
Compact model index: 1
diff --git a/gas/testsuite/gas/ia64/group-1.d b/gas/testsuite/gas/ia64/group-1.d
index a04a5ccf46e..5c712ab5ddd 100644
--- a/gas/testsuite/gas/ia64/group-1.d
+++ b/gas/testsuite/gas/ia64/group-1.d
@@ -8,15 +8,15 @@ Section Headers:
Size EntSize Flags Link Info Align
\[ 0\] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
- \[ 1\] \.group GROUP 0000000000000000 00000040
+ \[ 1\] \.group GROUP 0000000000000000 [0-9a-f]+
0000000000000008 0000000000000004 6 6 4
- \[ 2\] \.text PROGBITS 0000000000000000 00000050
+ \[ 2\] \.text PROGBITS 0000000000000000 [0-9a-f]+
0000000000000000 0000000000000000 AX 0 0 16
- \[ 3\] \.data PROGBITS 0000000000000000 00000050
+ \[ 3\] \.data PROGBITS 0000000000000000 [0-9a-f]+
0000000000000000 0000000000000000 WA 0 0 1
- \[ 4\] \.bss NOBITS 0000000000000000 00000050
+ \[ 4\] \.bss NOBITS 0000000000000000 [0-9a-f]+
0000000000000000 0000000000000000 WA 0 0 1
- \[ 5\] \.text PROGBITS 0000000000000000 00000050
+ \[ 5\] \.text PROGBITS 0000000000000000 [0-9a-f]+
0000000000000010 0000000000000000 AXG 0 0 16
\[ 6\] \.symtab SYMTAB 0000000000000000 .*
00000000000000c0 0000000000000018 7 8 8
diff --git a/gas/testsuite/gas/ia64/group-2.d b/gas/testsuite/gas/ia64/group-2.d
index 52a313a7d6f..91473dfb953 100644
--- a/gas/testsuite/gas/ia64/group-2.d
+++ b/gas/testsuite/gas/ia64/group-2.d
@@ -9,19 +9,19 @@ Section Headers:
Size EntSize Flags Link Info Align
\[ 0\] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
- \[ 1\] \.group GROUP 0000000000000000 00000040
+ \[ 1\] \.group GROUP 0000000000000000 [0-9a-f]+
0000000000000014 0000000000000004 9 5 4
- \[ 2\] \.text PROGBITS 0000000000000000 00000060
+ \[ 2\] \.text PROGBITS 0000000000000000 [0-9a-f]+
0000000000000000 0000000000000000 AX 0 0 16
- \[ 3\] \.data PROGBITS 0000000000000000 00000060
+ \[ 3\] \.data PROGBITS 0000000000000000 [0-9a-f]+
0000000000000000 0000000000000000 WA 0 0 1
- \[ 4\] \.bss NOBITS 0000000000000000 00000060
+ \[ 4\] \.bss NOBITS 0000000000000000 [0-9a-f]+
0000000000000000 0000000000000000 WA 0 0 1
- \[ 5\] \.gnu\.linkonce\.t\.f PROGBITS 0000000000000000 00000060
+ \[ 5\] \.gnu\.linkonce\.t\.f PROGBITS 0000000000000000 [0-9a-f]+
0000000000000000 0000000000000000 AXG 0 0 16
- \[ 6\] \.gnu\.linkonce\.ia6 PROGBITS 0000000000000000 00000060
+ \[ 6\] \.gnu\.linkonce\.ia6 PROGBITS 0000000000000000 [0-9a-f]+
0000000000000010 0000000000000000 AG 0 0 8
- \[ 7\] \.gnu\.linkonce\.ia6 IA_64_UNWIND 0000000000000000 00000070
+ \[ 7\] \.gnu\.linkonce\.ia6 IA_64_UNWIND 0000000000000000 [0-9a-f]+
0000000000000018 0000000000000000 ALG 5 5 8
\[ 8\] \.rela\.gnu\.linkonc RELA 0000000000000000 .*
0000000000000048 0000000000000018 IG 9 7 8
diff --git a/gas/testsuite/gas/mmix/bspec-2.d b/gas/testsuite/gas/mmix/bspec-2.d
index 2ade9b6d173..02ec04946a5 100644
--- a/gas/testsuite/gas/mmix/bspec-2.d
+++ b/gas/testsuite/gas/mmix/bspec-2.d
@@ -1,11 +1,11 @@
#readelf: -Sr -T -x1 -x4
There are 11 section headers, starting at offset .*:
#...
- \[ 4\] \.MMIX\.spec_data\.2 PROGBITS 0+ 0+48
+ \[ 4\] \.MMIX\.spec_data\.2 PROGBITS 0+ [0-9a-f]+
0+10 0+ 0 0 8
\[ 5\] \.rela\.MMIX\.spec_d RELA 0+ .*
+0+30 0+18 +I +8 +4 +8
- \[ 6\] \.MMIX\.spec_data\.3 PROGBITS 0+ 0+58
+ \[ 6\] \.MMIX\.spec_data\.3 PROGBITS 0+ [0-9a-f]+
0+8 0+ 0 0 8
\[ 7\] \.rela\.MMIX\.spec_d RELA 0+ .*
+0+18 +0+18 +I +8 +6 +8
diff --git a/ld/testsuite/ld-x86-64/pr27590.rd b/ld/testsuite/ld-x86-64/pr27590.rd
index 19469848c41..55ed17d6f7e 100644
--- a/ld/testsuite/ld-x86-64/pr27590.rd
+++ b/ld/testsuite/ld-x86-64/pr27590.rd
@@ -1,11 +1,11 @@
#...
- \[[ 0-9]+\] .gnu.debuglto_.debug_info PROGBITS +0+ 0+28a 0+42 00 +E 0 +0 1
- \[[ 0-9]+\] .rela.gnu.debuglto_.debug_info RELA +0+ 0+810 0+f0 18 +I 26 17 8
- \[[ 0-9]+\] .gnu.debuglto_.debug_abbrev PROGBITS +0+ 0+2cc 0+26 00 +E 0 +0 1
- \[[ 0-9]+\] .gnu.debuglto_.debug_macro PROGBITS +0+ 0+2f2 0+2a 00 +E 0 +0 1
- \[[ 0-9]+\] .rela.gnu.debuglto_.debug_macro RELA +0+ 0+900 0+60 18 +I 26 20 8
- \[[ 0-9]+\] .gnu.debuglto_.debug_macro PROGBITS +0+ 0+31c 0+10 00 GE 0 +0 1
- \[[ 0-9]+\] .rela.gnu.debuglto_.debug_macro RELA +0+ 0+960 0+30 18 IG 26 22 8
- \[[ 0-9]+\] .gnu.debuglto_.debug_line PROGBITS +0+ 0+32c 0+8a 00 +E 0 +0 1
- \[[ 0-9]+\] .gnu.debuglto_.debug_str PROGBITS +0+ 0+3b6 0+15c 01 MSE 0 +0 1
+ \[[ 0-9]+\] .gnu.debuglto_.debug_info PROGBITS +0+ [0-9a-f]+ 0+42 00 +E 0 +0 1
+ \[[ 0-9]+\] .rela.gnu.debuglto_.debug_info RELA +0+ [0-9a-f]+ 0+f0 18 +I 26 17 8
+ \[[ 0-9]+\] .gnu.debuglto_.debug_abbrev PROGBITS +0+ [0-9a-f]+ 0+26 00 +E 0 +0 1
+ \[[ 0-9]+\] .gnu.debuglto_.debug_macro PROGBITS +0+ [0-9a-f]+ 0+2a 00 +E 0 +0 1
+ \[[ 0-9]+\] .rela.gnu.debuglto_.debug_macro RELA +0+ [0-9a-f]+ 0+60 18 +I 26 20 8
+ \[[ 0-9]+\] .gnu.debuglto_.debug_macro PROGBITS +0+ [0-9a-f]+ 0+10 00 GE 0 +0 1
+ \[[ 0-9]+\] .rela.gnu.debuglto_.debug_macro RELA +0+ [0-9a-f]+ 0+30 18 IG 26 22 8
+ \[[ 0-9]+\] .gnu.debuglto_.debug_line PROGBITS +0+ [0-9a-f]+ 0+8a 00 +E 0 +0 1
+ \[[ 0-9]+\] .gnu.debuglto_.debug_str PROGBITS +0+ [0-9a-f]+ 0+15c 01 MSE 0 +0 1
#pass
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