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gdb, solib-svr4: remove locate_base()

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Whenever we call locate_base(), we clear info->debug_base directly before
the call.  Thus, we never cache the base location as locate_base() had
intended.

Move the svr4_have_link_map_offsets() check into elf_locate_base(), inline
locate_base() at all call sites, and remove it.
This commit is contained in:
Markus Metzger
2022-03-11 06:46:15 +01:00
parent 4428871653
commit 60d09f0a0d
1 changed files with 11 additions and 51 deletions
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62
gdb/solib-svr4.c
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@ -661,6 +661,9 @@ elf_locate_base (void)
struct bound_minimal_symbol msymbol;
CORE_ADDR dyn_ptr, dyn_ptr_addr;
if (!svr4_have_link_map_offsets ())
return 0;
/* Look for DT_MIPS_RLD_MAP first. MIPS executables use this
instead of DT_DEBUG, although they sometimes contain an unused
DT_DEBUG. */
@ -718,45 +721,6 @@ elf_locate_base (void)
return 0;
}
/* Locate the base address of dynamic linker structs.
For both the SunOS and SVR4 shared library implementations, if the
inferior executable has been linked dynamically, there is a single
address somewhere in the inferior's data space which is the key to
locating all of the dynamic linker's runtime structures. This
address is the value of the debug base symbol. The job of this
function is to find and return that address, or to return 0 if there
is no such address (the executable is statically linked for example).
For SunOS, the job is almost trivial, since the dynamic linker and
all of it's structures are statically linked to the executable at
link time. Thus the symbol for the address we are looking for has
already been added to the minimal symbol table for the executable's
objfile at the time the symbol file's symbols were read, and all we
have to do is look it up there. Note that we explicitly do NOT want
to find the copies in the shared library.
The SVR4 version is a bit more complicated because the address
is contained somewhere in the dynamic info section. We have to go
to a lot more work to discover the address of the debug base symbol.
Because of this complexity, we cache the value we find and return that
value on subsequent invocations. Note there is no copy in the
executable symbol tables. */
static CORE_ADDR
locate_base (struct svr4_info *info)
{
/* Check to see if we have a currently valid address, and if so, avoid
doing all this work again and just return the cached address. If
we have no cached address, try to locate it in the dynamic info
section for ELF executables. There's no point in doing any of this
though if we don't have some link map offsets to work with. */
if (info->debug_base == 0 && svr4_have_link_map_offsets ())
info->debug_base = elf_locate_base ();
return info->debug_base;
}
/* Find the first element in the inferior's dynamic link map, and
return its address in the inferior. Return zero if the address
could not be determined.
@ -844,9 +808,8 @@ svr4_keep_data_in_core (CORE_ADDR vaddr, unsigned long size)
info = get_svr4_info (current_program_space);
info->debug_base = 0;
locate_base (info);
if (!info->debug_base)
info->debug_base = elf_locate_base ();
if (info->debug_base == 0)
return 0;
ldsomap = solib_svr4_r_ldsomap (info);
@ -880,8 +843,8 @@ open_symbol_file_object (int from_tty)
return 0;
/* Always locate the debug struct, in case it has moved. */
info->debug_base = 0;
if (locate_base (info) == 0)
info->debug_base = elf_locate_base ();
if (info->debug_base == 0)
return 0; /* failed somehow... */
/* First link map member should be the executable. */
@ -1297,13 +1260,10 @@ svr4_current_sos_direct (struct svr4_info *info)
return library_list.head ? library_list.head : svr4_default_sos (info);
}
/* Always locate the debug struct, in case it has moved. */
info->debug_base = 0;
locate_base (info);
/* If we can't find the dynamic linker's base structure, this
must not be a dynamically linked executable. Hmm. */
if (! info->debug_base)
info->debug_base = elf_locate_base ();
if (info->debug_base == 0)
return svr4_default_sos (info);
/* Assume that everything is a library if the dynamic loader was loaded
@ -1839,8 +1799,8 @@ svr4_handle_solib_event (void)
return;
/* Always locate the debug struct, in case it moved. */
info->debug_base = 0;
if (locate_base (info) == 0)
info->debug_base = elf_locate_base ();
if (info->debug_base == 0)
{
/* It's possible for the reloc_complete probe to be triggered before
the linker has set the DT_DEBUG pointer (for example, when the