readelf vs. mapping symbols
Alan Modra
amodra@gmail.com
Fri Jan 30 21:16:11 GMT 2026
This reverts commit 45cf0b829303, which isn't needed after commit
6d7e5bcca5. Mapping symbols are like any other local symbol, and
shouldn't appear after the end of a section.
The real bug that resulted in both of these commits is that st_value
in an executable or shared library is the symbol address. It was
wrong to compare an address against a section size (you'd need to
subtract off the section vma first). The second commit limited the
warning to ET_REL where st_value is a section offset and thus can be
compared directly to the section size.
diff --git a/binutils/readelf.c b/binutils/readelf.c
index f50d9281ea4..c98569a14b4 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -14748,18 +14748,6 @@ print_symbol_size (uint64_t vma, int base)
}
}
-/* The AArch64, ARM and RISC-V architectures define mapping
- symbols (eg $d, $x, $t) which sometime should be ignored. */
-
-static bool
-is_mapping_symbol (const char * name)
-{
- return name[0] == '$'
- && name [1] != 0
- /* FIXME: Check that name[1] is lower case ASCII ? */
- && name [2] == 0;
-}
-
/* Print information on a single symbol. */
static void
@@ -14894,11 +14882,9 @@ print_symbol (Filedata * filedata,
warn (_("local symbol %" PRIu64 " found at index >= %s's sh_info value of %u\n"),
symbol_index, printable_section_name (filedata, section), section->sh_info);
- /* Local symbols (in objec files) whose value is larger than their section's
- size are suspicious especially if that section is mergeable - and hence
- might change offsets of the contents inside the section. Note - for
- some reason we can get mapping symbols that do not relate to their
- section's contents - so we ignore those type of symbol as well. */
+ /* Local symbols in ET_REL whose value is larger than their
+ section's size are suspicious if that section is mergeable - and
+ hence might change offsets of the contents inside the section. */
if (ELF_ST_BIND (psym->st_info) == STB_LOCAL
&& filedata->file_header.e_type == ET_REL
&& ! is_special
@@ -14906,8 +14892,7 @@ print_symbol (Filedata * filedata,
&& psym->st_shndx < filedata->file_header.e_shnum
&& filedata->section_headers != NULL
&& (filedata->section_headers[psym->st_shndx].sh_flags & SHF_MERGE)
- && psym->st_value > filedata->section_headers[psym->st_shndx].sh_size
- && ! is_mapping_symbol (strtab + psym->st_name))
+ && psym->st_value > filedata->section_headers[psym->st_shndx].sh_size)
warn (_("local symbol %s has a value (%#" PRIx64 ") which is larger than mergeable section %s's size (%#" PRIx64 ")\n"),
strtab + psym->st_name,
psym->st_value,
@@ -23476,7 +23461,9 @@ get_symbol_for_build_attribute (Filedata *filedata,
/* The AArch64, ARM and RISC-V architectures define mapping symbols
(eg $d, $x, $t) which we want to ignore. */
- if (is_mapping_symbol (ba_cache.strtab + sym->st_name))
+ if (ba_cache.strtab[sym->st_name] == '$'
+ && ba_cache.strtab[sym->st_name + 1] != 0
+ && ba_cache.strtab[sym->st_name + 2] == 0)
continue;
if (is_open_attr)
--
Alan Modra
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