[PATCH v3] Replace solib_global_lookup with gdbarch_iterate_over_objfiles_in_search_order

Christian Biesinger via gdb-patches
2019-08-27T23:03:38Z

[Test solib-corrupted.exp is now fixed]

All implementations of either function use it for the same purpose (except
Darwin, which is a no-op): to prefer a symbol in the current objfile over
symbols with the same name in other objfiles. There does not seem to be a
reason to have both mechanisms for that purpose.

gdb/ChangeLog:

2019-08-27 Christian Biesinger <cbiesinger@google.com>

* solib-darwin.c (darwin_lookup_lib_symbol): Remove.
(_initialize_darwin_solib): Don't set
darwin_so_ops.lookup_lib_global_symbol.
* solib-spu.c (spu_lookup_lib_symbol): Rename to...
(spu_iterate_over_objfiles_in_search_order): ...this,
and update to the iterate semantics.
(set_spu_solib_ops): Instead of setting lookup_lib_global_symbol,
call set_gdbarch_iterate_over_objfiles_in_search_order.
* solib-svr4.c (set_solib_svr4_fetch_link_map_offsets): Call
set_gdbarch_iterate_over_objfiles_in_search_order.
(elf_lookup_lib_symbol): Rename to...
(svr4_iterate_over_objfiles_in_search_order): this, and update
to iterate semantics.
(_initialize_svr4_solib): Don't set lookup_lib_global_symbol.
* solib-svr4.h: Declare svr4_iterate_over_objfiles_in_search_order.
* solib.c (solib_global_lookup): Remove.
* solist.h (struct target_so_ops): Remove lookup_lib_global_symbol.
(solib_global_lookup): Remove.
* symtab.c (lookup_global_or_static_symbol): Remove call to
solib_global_lookup.
---
gdb/solib-darwin.c | 9 ---------
gdb/solib-spu.c | 27 ++++++++++++++------------
gdb/solib-svr4.c | 48 ++++++++++++++++++++++++++++------------------
gdb/solib-svr4.h | 5 +++++
gdb/solib.c | 15 ---------------
gdb/solist.h | 11 -----------
gdb/symtab.c | 6 +-----
7 files changed, 50 insertions(+), 71 deletions(-)

diff --git a/gdb/solib-darwin.c b/gdb/solib-darwin.c
index 443ebb64a4..b386cd35ed 100644
--- a/gdb/solib-darwin.c
+++ b/gdb/solib-darwin.c
@@ -638,14 +638,6 @@ darwin_relocate_section_addresses (struct so_list *so,
so->addr_low = sec->addr;
}
\f
-static struct block_symbol
-darwin_lookup_lib_symbol (struct objfile *objfile,
- const char *name,
- const domain_enum domain)
-{
- return {};
-}
-
static gdb_bfd_ref_ptr
darwin_bfd_open (const char *pathname)
{
@@ -688,6 +680,5 @@ _initialize_darwin_solib (void)
darwin_so_ops.current_sos = darwin_current_sos;
darwin_so_ops.open_symbol_file_object = open_symbol_file_object;
darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code;
- darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol;
darwin_so_ops.bfd_open = darwin_bfd_open;
}
diff --git a/gdb/solib-spu.c b/gdb/solib-spu.c
index 5b97b9bcf6..ed33a0adf2 100644
--- a/gdb/solib-spu.c
+++ b/gdb/solib-spu.c
@@ -385,19 +385,21 @@ spu_bfd_open (const char *pathname)
return abfd;
}

-/* Lookup global symbol in a SPE executable. */
-static struct block_symbol
-spu_lookup_lib_symbol (struct objfile *objfile,
- const char *name,
- const domain_enum domain)
+/* Search order prefers the current objfile for SPE executables. */
+static void
+spu_iterate_over_objfiles_in_search_order
+ (struct gdbarch *gdbarch,
+ iterate_over_objfiles_in_search_order_cb_ftype *cb,
+ void *cb_data, struct objfile *objfile)
{
- if (bfd_get_arch (objfile->obfd) == bfd_arch_spu)
- return lookup_global_symbol_from_objfile (objfile, GLOBAL_BLOCK, name,
- domain);
+ if (objfile != nullptr && bfd_get_arch (objfile->obfd) == bfd_arch_spu)
+ {
+ if (cb (objfile, cb_data) != 0)
+ return;
+ }

- if (svr4_so_ops.lookup_lib_global_symbol != NULL)
- return svr4_so_ops.lookup_lib_global_symbol (objfile, name, domain);
- return {};
+ return svr4_iterate_over_objfiles_in_search_order(
+ gdbarch, cb, cb_data, objfile);
}

/* Enable shared library breakpoint. */
@@ -515,9 +517,10 @@ set_spu_solib_ops (struct gdbarch *gdbarch)
spu_so_ops.free_so = spu_free_so;
spu_so_ops.current_sos = spu_current_sos;
spu_so_ops.bfd_open = spu_bfd_open;
- spu_so_ops.lookup_lib_global_symbol = spu_lookup_lib_symbol;
}

+ set_gdbarch_iterate_over_objfiles_in_search_order
+ (gdbarch, spu_iterate_over_objfiles_in_search_order);
set_solib_ops (gdbarch, &spu_so_ops);
}

diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index c0c505acaa..e595a3572b 100644
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -3104,6 +3104,8 @@ set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch,
ops->fetch_link_map_offsets = flmo;

set_solib_ops (gdbarch, &svr4_so_ops);
+ set_gdbarch_iterate_over_objfiles_in_search_order
+ (gdbarch, svr4_iterate_over_objfiles_in_search_order);
}

/* Fetch a link_map_offsets structure using the architecture-specific
@@ -3202,32 +3204,41 @@ svr4_lp64_fetch_link_map_offsets (void)

struct target_so_ops svr4_so_ops;

-/* Lookup global symbol for ELF DSOs linked with -Bsymbolic. Those DSOs have a
+/* Search order for ELF DSOs linked with -Bsymbolic. Those DSOs have a
different rule for symbol lookup. The lookup begins here in the DSO, not in
the main executable. */

-static struct block_symbol
-elf_lookup_lib_symbol (struct objfile *objfile,
- const char *name,
- const domain_enum domain)
+void
+svr4_iterate_over_objfiles_in_search_order
+ (struct gdbarch *gdbarch,
+ iterate_over_objfiles_in_search_order_cb_ftype *cb,
+ void *cb_data, struct objfile *current_objfile)
{
- bfd *abfd;
-
- if (objfile == symfile_objfile)
- abfd = exec_bfd;
- else
+ if (current_objfile != nullptr)
{
- /* OBJFILE should have been passed as the non-debug one. */
- gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
+ bfd *abfd;

- abfd = objfile->obfd;
- }
+ if (current_objfile->separate_debug_objfile_backlink != nullptr)
+ current_objfile = current_objfile->separate_debug_objfile_backlink;

- if (abfd == NULL || scan_dyntag (DT_SYMBOLIC, abfd, NULL, NULL) != 1)
- return {};
+ if (current_objfile == symfile_objfile)
+ abfd = exec_bfd;
+ else
+ abfd = current_objfile->obfd;
+
+ if (abfd != nullptr &&
+ scan_dyntag (DT_SYMBOLIC, abfd, nullptr, nullptr) == 1)
+ {
+ if (cb (current_objfile, cb_data) != 0)
+ return;
+ }
+ }

- return lookup_global_symbol_from_objfile (objfile, GLOBAL_BLOCK, name,
- domain);
+ for (objfile *objfile : current_program_space->objfiles ())
+ {
+ if (cb (objfile, cb_data) != 0)
+ return;
+ }
}

void
@@ -3244,7 +3255,6 @@ _initialize_svr4_solib (void)
svr4_so_ops.open_symbol_file_object = open_symbol_file_object;
svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code;
svr4_so_ops.bfd_open = solib_bfd_open;
- svr4_so_ops.lookup_lib_global_symbol = elf_lookup_lib_symbol;
svr4_so_ops.same = svr4_same;
svr4_so_ops.keep_data_in_core = svr4_keep_data_in_core;
svr4_so_ops.update_breakpoints = svr4_update_solib_event_breakpoints;
diff --git a/gdb/solib-svr4.h b/gdb/solib-svr4.h
index a051e70b79..b99b8e2e3a 100644
--- a/gdb/solib-svr4.h
+++ b/gdb/solib-svr4.h
@@ -21,6 +21,7 @@
#define SOLIB_SVR4_H

#include "solist.h"
+#include "gdbarch.h"

struct objfile;
struct target_so_ops;
@@ -107,4 +108,8 @@ extern struct link_map_offsets *svr4_lp64_fetch_link_map_offsets (void);
SVR4 run time loader. */
int svr4_in_dynsym_resolve_code (CORE_ADDR pc);

+extern void svr4_iterate_over_objfiles_in_search_order (
+ struct gdbarch *gdbarch, iterate_over_objfiles_in_search_order_cb_ftype *cb,
+ void *cb_data, struct objfile *objfile);
+
#endif /* solib-svr4.h */
diff --git a/gdb/solib.c b/gdb/solib.c
index 29a17ad5d4..ec3bf06c50 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -1441,21 +1441,6 @@ show_auto_solib_add (struct ui_file *file, int from_tty,
}

-/* Handler for library-specific lookup of global symbol NAME in OBJFILE. Call
- the library-specific handler if it is installed for the current target. */
-
-struct block_symbol
-solib_global_lookup (struct objfile *objfile,
- const char *name,
- const domain_enum domain)
-{
- const struct target_so_ops *ops = solib_ops (target_gdbarch ());
-
- if (ops->lookup_lib_global_symbol != NULL)
- return ops->lookup_lib_global_symbol (objfile, name, domain);
- return {};
-}
-
/* Lookup the value for a specific symbol from dynamic symbol table. Look
up symbol from ABFD. MATCH_SYM is a callback function to determine
whether to pick up a symbol. DATA is the input of this callback
diff --git a/gdb/solist.h b/gdb/solist.h
index e1410c2b79..ee99fc815b 100644
--- a/gdb/solist.h
+++ b/gdb/solist.h
@@ -139,12 +139,6 @@ struct target_so_ops
unsigned o_flags,
gdb::unique_xmalloc_ptr<char> *temp_pathname);

- /* Hook for looking up global symbols in a library-specific way. */
- struct block_symbol (*lookup_lib_global_symbol)
- (struct objfile *objfile,
- const char *name,
- const domain_enum domain);
-
/* Given two so_list objects, one from the GDB thread list
and another from the list returned by current_sos, return 1
if they represent the same library.
@@ -209,9 +203,4 @@ extern gdb_bfd_ref_ptr solib_bfd_open (const char *in_pathname);
/* FIXME: gdbarch needs to control this variable. */
extern struct target_so_ops *current_target_so_ops;

-/* Handler for library-specific global symbol lookup in solib.c. */
-struct block_symbol solib_global_lookup (struct objfile *objfile,
- const char *name,
- const domain_enum domain);
-
#endif
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 7762c85708..c74f39c3cd 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -2637,11 +2637,7 @@ lookup_global_or_static_symbol (const char *name,
return result;
}

- /* Call library-specific lookup procedure. */
- if (objfile != NULL)
- result = solib_global_lookup (objfile, name, domain);
-
- /* If that didn't work go a global search (of global blocks, heh). */
+ /* Do a global search (of global blocks, heh). */
if (result.symbol == NULL)
{
memset (&lookup_data, 0, sizeof (lookup_data));
--
2.23.0.187.g17f5b7556c-goog