From: Markus Metzger <markus.t.metzger@intel.com>
To: gdb-patches@sourceware.org
Subject: [PATCH v5 02/15] gdb, solib-svr4: remove locate_base()
Date: Thu, 2 Jun 2022 15:25:01 +0200 [thread overview]
Message-ID: <20220602132514.957983-3-markus.t.metzger@intel.com> (raw)
In-Reply-To: <20220602132514.957983-1-markus.t.metzger@intel.com>
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.
---
gdb/solib-svr4.c | 62 +++++++++---------------------------------------
1 file changed, 11 insertions(+), 51 deletions(-)
diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index 5c046d3fab5..6222f79a7a0 100644
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -662,6 +662,9 @@ 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. */
@@ -719,45 +722,6 @@ 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.
@@ -845,9 +809,8 @@ 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);
@@ -881,8 +844,8 @@ 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. */
@@ -1298,13 +1261,10 @@ 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
@@ -1840,8 +1800,8 @@ 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
--
2.35.3
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next prev parent reply other threads:[~2022-06-02 14:28 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-02 13:24 [PATCH v5 00/15] basic linker namespace support Markus Metzger
2022-06-02 13:25 ` [PATCH v5 01/15] gdb, testsuite: extend gdb_test_multiple checks Markus Metzger
2022-06-13 1:28 ` Kevin Buettner
2022-06-02 13:25 ` Markus Metzger [this message]
2022-06-02 23:04 ` [PATCH v5 02/15] gdb, solib-svr4: remove locate_base() Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 03/15] gdb, gdbserver: support dlmopen() Markus Metzger
2022-06-19 4:02 ` Kevin Buettner
2022-06-27 12:55 ` Metzger, Markus T
2022-06-30 22:35 ` Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 04/15] gdbserver: move main_lm handling into caller Markus Metzger
2022-06-19 4:22 ` Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 05/15] gdb, gdbserver: extend RSP to support namespaces Markus Metzger
2022-06-02 16:09 ` Eli Zaretskii
2022-06-19 4:32 ` Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 06/15] gdb, compile: unlink objfile stored in module Markus Metzger
2022-06-23 17:20 ` Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 07/15] gdb, python: use gdbarch_iterate_over_objfiles_in_search_order Markus Metzger
2022-06-24 17:18 ` Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 08/15] gdb, ada: collect standard exceptions in all objfiles Markus Metzger
2022-06-24 17:26 ` Kevin Buettner
2022-07-18 16:49 ` Tom Tromey
2022-07-18 5:35 ` Metzger, Markus T
2022-09-14 8:19 ` Metzger, Markus T
2022-09-14 8:37 ` Joel Brobecker
2022-09-14 8:45 ` Metzger, Markus T
2022-06-02 13:25 ` [PATCH v5 09/15] gdb, ada: update ada_lookup_simple_minsym Markus Metzger
2022-06-24 23:42 ` Kevin Buettner
2022-07-18 17:02 ` Tom Tromey
2022-07-19 7:14 ` Metzger, Markus T
2022-09-14 8:19 ` Metzger, Markus T
2022-09-21 16:11 ` Tom Tromey
2022-06-02 13:25 ` [PATCH v5 10/15] gdb, ada: update ada_add_all_symbols Markus Metzger
2022-06-24 23:53 ` Kevin Buettner
2022-07-18 5:36 ` Metzger, Markus T
2022-07-18 16:56 ` Tom Tromey
2022-07-19 7:13 ` Metzger, Markus T
2022-07-19 12:23 ` Tom Tromey
2022-07-19 13:49 ` Metzger, Markus T
2022-06-02 13:25 ` [PATCH v5 11/15] gdb, cp: update add_symbol_overload_list_qualified Markus Metzger
2022-06-24 23:59 ` Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 12/15] gdb, hppa: remove unused hppa_lookup_stub_minimal_symbol Markus Metzger
2022-06-25 0:01 ` Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 13/15] gdb, symtab: inline find_quick_global_symbol_language Markus Metzger
2022-06-25 0:16 ` Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 14/15] gdb: update gnu ifunc resolve Markus Metzger
2022-06-25 0:34 ` Kevin Buettner
2022-06-02 13:25 ` [PATCH v5 15/15] gdb, solib-svr4: support namespaces in DSO iteration Markus Metzger
2022-06-25 0:42 ` Kevin Buettner
2022-07-15 10:30 ` [PATCH v5 00/15] basic linker namespace support Metzger, Markus T
2022-07-16 0:04 ` Kevin Buettner
2022-07-18 5:33 ` Metzger, Markus T
2022-10-05 11:16 ` Metzger, Markus T
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