[PATCH 4/9] Add a new gdbarch method to resolve the address of TLS variables.

John Baldwin
2019-01-22T18:52:27Z

Permit TLS variable addresses to be resolved purely by an ABI rather
than requiring a target method. This doesn't try the target method if
the ABI function is present (even if the ABI function fails) to
simplify error handling.

gdb/ChangeLog:

* gdbarch.sh (get_thread_local_address): New method.
* gdbarch.h, gdbarch.c: Regenerate.
* target.c (target_translate_tls_address): Use
gdbarch_get_thread_local_address if present instead of
target::get_thread_local_address.
---
gdb/ChangeLog | 8 ++++++++
gdb/gdbarch.c | 32 ++++++++++++++++++++++++++++++++
gdb/gdbarch.h | 6 ++++++
gdb/gdbarch.sh | 1 +
gdb/target.c | 13 ++++++++-----
5 files changed, 55 insertions(+), 5 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c02e534fe5..7c46bb0009 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,11 @@
+2019-01-22 John Baldwin <jhb@FreeBSD.org>
+
+ * gdbarch.sh (get_thread_local_address): New method.
+ * gdbarch.h, gdbarch.c: Regenerate.
+ * target.c (target_translate_tls_address): Use
+ gdbarch_get_thread_local_address if present instead of
+ target::get_thread_local_address.
+
2019-01-22 John Baldwin <jhb@FreeBSD.org>

* solib-svr4.c (svr4_fetch_objfile_link_map): Look for
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index 434ee3bfcf..2b3fcef004 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -251,6 +251,7 @@ struct gdbarch
CORE_ADDR deprecated_function_start_offset;
gdbarch_remote_register_number_ftype *remote_register_number;
gdbarch_fetch_tls_load_module_address_ftype *fetch_tls_load_module_address;
+ gdbarch_get_thread_local_address_ftype *get_thread_local_address;
CORE_ADDR frame_args_skip;
gdbarch_unwind_pc_ftype *unwind_pc;
gdbarch_unwind_sp_ftype *unwind_sp;
@@ -613,6 +614,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
/* Skip verify of deprecated_function_start_offset, invalid_p == 0 */
/* Skip verify of remote_register_number, invalid_p == 0 */
/* Skip verify of fetch_tls_load_module_address, has predicate. */
+ /* Skip verify of get_thread_local_address, has predicate. */
/* Skip verify of frame_args_skip, invalid_p == 0 */
/* Skip verify of unwind_pc, invalid_p == 0 */
/* Skip verify of unwind_sp, invalid_p == 0 */
@@ -1073,6 +1075,12 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
fprintf_unfiltered (file,
"gdbarch_dump: get_syscall_number = <%s>\n",
host_address_to_string (gdbarch->get_syscall_number));
+ fprintf_unfiltered (file,
+ "gdbarch_dump: gdbarch_get_thread_local_address_p() = %d\n",
+ gdbarch_get_thread_local_address_p (gdbarch));
+ fprintf_unfiltered (file,
+ "gdbarch_dump: get_thread_local_address = <%s>\n",
+ host_address_to_string (gdbarch->get_thread_local_address));
fprintf_unfiltered (file,
"gdbarch_dump: gnu_triplet_regexp = <%s>\n",
host_address_to_string (gdbarch->gnu_triplet_regexp));
@@ -3018,6 +3026,30 @@ set_gdbarch_fetch_tls_load_module_address (struct gdbarch *gdbarch,
gdbarch->fetch_tls_load_module_address = fetch_tls_load_module_address;
}

+int
+gdbarch_get_thread_local_address_p (struct gdbarch *gdbarch)
+{
+ gdb_assert (gdbarch != NULL);
+ return gdbarch->get_thread_local_address != NULL;
+}
+
+CORE_ADDR
+gdbarch_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid, CORE_ADDR lm_addr, CORE_ADDR offset)
+{
+ gdb_assert (gdbarch != NULL);
+ gdb_assert (gdbarch->get_thread_local_address != NULL);
+ if (gdbarch_debug >= 2)
+ fprintf_unfiltered (gdb_stdlog, "gdbarch_get_thread_local_address called\n");
+ return gdbarch->get_thread_local_address (gdbarch, ptid, lm_addr, offset);
+}
+
+void
+set_gdbarch_get_thread_local_address (struct gdbarch *gdbarch,
+ gdbarch_get_thread_local_address_ftype get_thread_local_address)
+{
+ gdbarch->get_thread_local_address = get_thread_local_address;
+}
+
CORE_ADDR
gdbarch_frame_args_skip (struct gdbarch *gdbarch)
{
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 5b265a462a..e11144941f 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -649,6 +649,12 @@ typedef CORE_ADDR (gdbarch_fetch_tls_load_module_address_ftype) (struct objfile
extern CORE_ADDR gdbarch_fetch_tls_load_module_address (struct gdbarch *gdbarch, struct objfile *objfile);
extern void set_gdbarch_fetch_tls_load_module_address (struct gdbarch *gdbarch, gdbarch_fetch_tls_load_module_address_ftype *fetch_tls_load_module_address);

+extern int gdbarch_get_thread_local_address_p (struct gdbarch *gdbarch);
+
+typedef CORE_ADDR (gdbarch_get_thread_local_address_ftype) (struct gdbarch *gdbarch, ptid_t ptid, CORE_ADDR lm_addr, CORE_ADDR offset);
+extern CORE_ADDR gdbarch_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid, CORE_ADDR lm_addr, CORE_ADDR offset);
+extern void set_gdbarch_get_thread_local_address (struct gdbarch *gdbarch, gdbarch_get_thread_local_address_ftype *get_thread_local_address);
+
extern CORE_ADDR gdbarch_frame_args_skip (struct gdbarch *gdbarch);
extern void set_gdbarch_frame_args_skip (struct gdbarch *gdbarch, CORE_ADDR frame_args_skip);

diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index afc4da7cdd..09097bcbaf 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -602,6 +602,7 @@ m;int;remote_register_number;int regno;regno;;default_remote_register_number;;0

# Fetch the target specific address used to represent a load module.
F;CORE_ADDR;fetch_tls_load_module_address;struct objfile *objfile;objfile
+M;CORE_ADDR;get_thread_local_address;ptid_t ptid, CORE_ADDR lm_addr, CORE_ADDR offset;ptid, lm_addr, offset
#
v;CORE_ADDR;frame_args_skip;;;0;;;0
m;CORE_ADDR;unwind_pc;struct frame_info *next_frame;next_frame;;default_unwind_pc;;0
diff --git a/gdb/target.c b/gdb/target.c
index ad7eba3fa3..54d90e4f34 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -691,8 +691,9 @@ target_translate_tls_address (struct objfile *objfile, CORE_ADDR offset)
{
volatile CORE_ADDR addr = 0;
struct target_ops *target = current_top_target ();
+ struct gdbarch *gdbarch = target_gdbarch ();

- if (gdbarch_fetch_tls_load_module_address_p (target_gdbarch ()))
+ if (gdbarch_fetch_tls_load_module_address_p (gdbarch))
{
ptid_t ptid = inferior_ptid;

@@ -701,10 +702,14 @@ target_translate_tls_address (struct objfile *objfile, CORE_ADDR offset)
CORE_ADDR lm_addr;

/* Fetch the load module address for this objfile. */
- lm_addr = gdbarch_fetch_tls_load_module_address (target_gdbarch (),
+ lm_addr = gdbarch_fetch_tls_load_module_address (gdbarch,
objfile);

- addr = target->get_thread_local_address (ptid, lm_addr, offset);
+ if (gdbarch_get_thread_local_address_p (gdbarch))
+ addr = gdbarch_get_thread_local_address (gdbarch, ptid, lm_addr,
+ offset);
+ else
+ addr = target->get_thread_local_address (ptid, lm_addr, offset);
}
/* If an error occurred, print TLS related messages here. Otherwise,
throw the error to some higher catcher. */
@@ -759,8 +764,6 @@ target_translate_tls_address (struct objfile *objfile, CORE_ADDR offset)
}
END_CATCH
}
- /* It wouldn't be wrong here to try a gdbarch method, too; finding
- TLS is an ABI-specific thing. But we don't do that yet. */
else
error (_("Cannot find thread-local variables on this target"));

--
2.19.2