Hi.
The previous patch was not correct. This one should be.
Ready for master?
Thanks,
Martin
>From a96f7ae39b5d56ce886edf1bfb9ca6475a857652 Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Mon, 5 Oct 2020 18:03:08 +0200
Subject: [PATCH] lto: fix LTO debug sections copying.
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readelf -S prints:
There are 81999 section headers, starting at offset 0x1f488060:
Section Headers:
[Nr] Name Type Address Off Size ES Flg Lk Inf Al
[ 0] NULL 0000000000000000 000000 01404f 00 81998 0 0
[ 1] .group GROUP 0000000000000000 000040 000008 04 81995 105027 4
...
[81995] .symtab SYMTAB 0000000000000000 d5d9298 2db310 18 81997 105026 8
[81996] .symtab_shndx SYMTAB SECTION INDICES 0000000000000000 d8b45a8 079dd8 04 81995 0 4
[81997] .strtab STRTAB 0000000000000000 d92e380 80460c 00 0 0 1
...
Looking at the documentation:
Table 7–15 ELF sh_link and sh_info Interpretation
sh_type - sh_link
SHT_SYMTAB - The section header index of the associated string table.
SHT_SYMTAB_SHNDX - The section header index of the associated symbol table.
As seen, sh_link of a SHT_SYMTAB always points to a .strtab and readelf
confirms that.
So we need to use reverse mapping taken from
[81996] .symtab_shndx SYMTAB SECTION INDICES 0000000000000000 d8b45a8 079dd8 04 81995 0 4
where sh_link points to 81995.
libiberty/ChangeLog:
PR lto/97290
* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
Use sh_link of a .symtab_shndx section.
---
libiberty/simple-object-elf.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/libiberty/simple-object-elf.c b/libiberty/simple-object-elf.c
index 7c9d492f6a4..37e73348cb7 100644
--- a/libiberty/simple-object-elf.c
+++ b/libiberty/simple-object-elf.c
@@ -1191,7 +1191,7 @@ simple_object_elf_copy_lto_debug_sections (simple_object_read *sobj,
unsigned int sh_link;
sh_link = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
shdr, sh_link, Elf_Word);
- symtab_indices_shndx[sh_link - 1] = i;
+ symtab_indices_shndx[sh_link - 1] = i - 1;
/* Always discard the extended index sections, after
copying it will not be needed. This way we don't need to
update it and deal with the ordering constraints of
@@ -1372,19 +1372,22 @@ simple_object_elf_copy_lto_debug_sections (simple_object_read *sobj,
{
unsigned entsize = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
shdr, sh_entsize, Elf_Addr);
- unsigned strtab = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
- shdr, sh_link, Elf_Word);
size_t prevailing_name_idx = 0;
unsigned char *ent;
unsigned *shndx_table = NULL;
/* Read the section index table if present. */
if (symtab_indices_shndx[i - 1] != 0)
{
- unsigned char *sidxhdr = shdrs + (strtab - 1) * shdr_size;
+ unsigned char *sidxhdr = shdrs + symtab_indices_shndx[i - 1] * shdr_size;
off_t sidxoff = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
sidxhdr, sh_offset, Elf_Addr);
size_t sidxsz = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
sidxhdr, sh_size, Elf_Addr);
+ unsigned int shndx_type
+ = ELF_FETCH_FIELD (type_functions, ei_class, Shdr,
+ sidxhdr, sh_type, Elf_Word);
+ if (shndx_type != SHT_SYMTAB_SHNDX)
+ return "Wrong section type of a SYMTAB SECTION INDICES section";
shndx_table = (unsigned *)XNEWVEC (char, sidxsz);
simple_object_internal_read (sobj->descriptor,
sobj->offset + sidxoff,
--
2.28.0
