Toolchain/binutils-gdb
1
0
Fork 0
forked from Imagelibrary/binutils-gdb
Code Pull Requests Activity

gdb: Allow replayed threads to read and write pseudo registers

Browse Source 
In an effort to support AVX instructions when recording, we need to
allow replaying threads to access pseudo registers. Currently, if
we try to do that gdb will fail in a call to validate_registers_access,
because the thread is executing so GDB thinks it is unsafe to read
pseudo registers.

When replaying, the thread is really executing for all intents and
purposes, but the execution is just having GDB change values on
registers, so it will always be safe to read and write pseudo registers.
This commit changes functions that check for register access to allow
access when we are replaying. The check to whether we are replaying must
not happen when writing a core file, as record_full_list could be nullptr,
so we only check it if the thread is executing.

As of this commit, I don't know of a way to trigger this commit without
AVX support on record, so a test isn't provided. However, as soon as
record-full supports saving ymm registers, the AVX tests will test this
as well.

Approved-By: Tom Tromey <tom@tromey.com>
This commit is contained in:
Guinevere Larsen
2024-06-19 17:16:33 -03:00
parent 917ed12066
commit 2f46cda83b
3 changed files with 25 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
gdb/record-full.c
View File

@@ -370,6 +370,15 @@ record_full_is_used (void)
|| t == &record_full_core_ops);
}
/* see record-full.h. */
bool
record_full_is_replaying ()
{
auto target = dynamic_cast<record_full_target *>
(current_inferior ()->target_at (record_stratum));
return target != nullptr && RECORD_FULL_IS_REPLAY;
}
/* Command lists for "set/show record full". */
static struct cmd_list_element *set_record_full_cmdlist;

3
gdb/record-full.h
View File

@@ -31,6 +31,9 @@ extern int record_full_arch_list_add_end (void);
/* Returns true if the process record target is open. */
extern int record_full_is_used (void);
/* Whether the inferior is being replayed, or is executing normally. */
extern bool record_full_is_replaying ();
extern scoped_restore_tmpl<int> record_full_gdb_operation_disable_set ();
#endif /* RECORD_FULL_H */

15
gdb/thread.c
View File

@@ -50,6 +50,7 @@
#include "inline-frame.h"
#include "stack.h"
#include "interps.h"
#include "record-full.h"
/* See gdbthread.h. */
@@ -998,7 +999,13 @@ validate_registers_access (void)
reason, but is marked running from the user's perspective. E.g.,
the thread is waiting for its turn in the step-over queue. */
if (tp->executing ())
error (_("Selected thread is running."));
{
/* If we are replaying with the record-full subsystem, even though
the thread is executing, it is always safe to read from it since
replay execution is just GDB reading and writing to a regcache. */
if (!record_full_is_replaying ())
error (_("Selected thread is running."));
}
}
/* See gdbthread.h. */
@@ -1016,7 +1023,11 @@ can_access_registers_thread (thread_info *thread)
/* ... or from a spinning thread. FIXME: see validate_registers_access. */
if (thread->executing ())
return false;
{
/* See validate_registers_access. */
if (!record_full_is_replaying ())
return false;
}
return true;
}