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Change how versioned symbols are recorded

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A change to BFD caused a gdb regression when using the Ada "catch
exception" feature.  The bug is visible when a shared library throws
an exception that is caught in the main executable.

This was discussed here:

https://sourceware.org/pipermail/binutils/2021-July/117538.html

This patch implements Alan's proposed fix, namely to use VERSYM_HIDDEN
rather than the name when deciding to install a version-less symbol.

The internal test case is identical to the catch_ex_std.exp that is
in-tree, so I haven't added a new test.  I could not make that one
fail on x86-64 Linux, though.  It's possible that maybe I'd have to
update the system linker first, but I didn't want to try that.

Regression tested on x86-64 Fedora 32.
This commit is contained in:
Tom Tromey 2021-08-03 12:42:43 -06:00
parent 72df4c816f
commit 28a4e64dd1
1 changed files with 33 additions and 34 deletions
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67
gdb/elfread.c
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@ -266,6 +266,8 @@ elf_symtab_read (minimal_symbol_reader &reader,
continue;
}
elf_symbol_type *elf_sym = (elf_symbol_type *) sym;
/* Skip "special" symbols, e.g. ARM mapping symbols. These are
symbols which do not correspond to objects in the symbol table,
but have some other target-specific meaning. */
@ -373,7 +375,7 @@ elf_symtab_read (minimal_symbol_reader &reader,
NOTE: uweigand-20071112: Synthetic symbols do not
have an ELF-private part, so do not touch those. */
unsigned int shndx = type == ST_SYNTHETIC ? 0 :
((elf_symbol_type *) sym)->internal_elf_sym.st_shndx;
elf_sym->internal_elf_sym.st_shndx;
switch (shndx)
{
@ -481,7 +483,6 @@ elf_symtab_read (minimal_symbol_reader &reader,
if (type != ST_SYNTHETIC)
{
/* Pass symbol size field in via BFD. FIXME!!! */
elf_symbol_type *elf_sym = (elf_symbol_type *) sym;
SET_MSYMBOL_SIZE (msym, elf_sym->internal_elf_sym.st_size);
}
@ -495,41 +496,39 @@ elf_symtab_read (minimal_symbol_reader &reader,
if (msym != NULL)
{
const char *atsign = strchr (sym->name, '@');
bool is_at_symbol = atsign != nullptr && atsign > sym->name;
bool is_plt = is_at_symbol && strcmp (atsign, "@plt") == 0;
int len = is_at_symbol ? atsign - sym->name : 0;
if (atsign != NULL && atsign[1] == '@' && atsign > sym->name)
if (is_at_symbol
&& !is_plt
&& (elf_sym->version & VERSYM_HIDDEN) == 0)
record_minimal_symbol (reader,
gdb::string_view (sym->name, len),
true, symaddr, ms_type, sym->section,
objfile);
else if (is_plt)
{
int len = atsign - sym->name;
record_minimal_symbol (reader,
gdb::string_view (sym->name, len),
true, symaddr, ms_type, sym->section,
objfile);
}
}
/* For @plt symbols, also record a trampoline to the
destination symbol. The @plt symbol will be used in
disassembly, and the trampoline will be used when we are
trying to find the target. */
if (msym && ms_type == mst_text && type == ST_SYNTHETIC)
{
int len = strlen (sym->name);
if (len > 4 && strcmp (sym->name + len - 4, "@plt") == 0)
{
struct minimal_symbol *mtramp;
mtramp = record_minimal_symbol
(reader, gdb::string_view (sym->name, len - 4), true,
symaddr, mst_solib_trampoline, sym->section, objfile);
if (mtramp)
/* For @plt symbols, also record a trampoline to the
destination symbol. The @plt symbol will be used
in disassembly, and the trampoline will be used
when we are trying to find the target. */
if (ms_type == mst_text && type == ST_SYNTHETIC)
{
SET_MSYMBOL_SIZE (mtramp, MSYMBOL_SIZE (msym));
mtramp->created_by_gdb = 1;
mtramp->filename = filesymname;
if (elf_make_msymbol_special_p)
gdbarch_elf_make_msymbol_special (gdbarch,
sym, mtramp);
struct minimal_symbol *mtramp;
mtramp = record_minimal_symbol
(reader, gdb::string_view (sym->name, len), true,
symaddr, mst_solib_trampoline, sym->section, objfile);
if (mtramp)
{
SET_MSYMBOL_SIZE (mtramp, MSYMBOL_SIZE (msym));
mtramp->created_by_gdb = 1;
mtramp->filename = filesymname;
if (elf_make_msymbol_special_p)
gdbarch_elf_make_msymbol_special (gdbarch,
sym, mtramp);
}
}
}
}