[PATCH v3 14/29] Share thread_rec between gdb and gdbserver

Tom Tromey
2020-03-13T19:09:01Z

This changes gdb and gdbserver to use the same calling convention for
the "thread_rec" helper function. Fully merging these is difficult
due to differences in how threads are managed by the enclosing
applications; but sharing a declaration makes it possible for future
shared code to call this method.

gdb/ChangeLog
2020-03-13 Tom Tromey <tromey@adacore.com>

* windows-nat.c (enum thread_disposition_type): Move to
nat/windows-nat.h.
(windows_nat::thread_rec): Rename from thread_rec. No longer
static.
(windows_add_thread, windows_nat_target::fetch_registers)
(windows_nat_target::store_registers, handle_exception)
(windows_nat_target::resume, get_windows_debug_event)
(windows_nat_target::get_tib_address)
(windows_nat_target::thread_name)
(windows_nat_target::thread_alive): Update.
* nat/windows-nat.h (enum thread_disposition_type): Move from
windows-nat.c.
(thread_rec): Declare.

gdbserver/ChangeLog
2020-03-13 Tom Tromey <tromey@adacore.com>

* win32-low.c (windows_nat::thread_rec): Rename from thread_rec.
No longer static. Change parameters.
(child_add_thread, child_fetch_inferior_registers)
(child_store_inferior_registers, win32_resume)
(win32_get_tib_address): Update.
---
gdb/ChangeLog | 16 +++++++++++
gdb/nat/windows-nat.h | 21 +++++++++++++++
gdb/windows-nat.c | 61 +++++++++++++++---------------------------
gdbserver/ChangeLog | 8 ++++++
gdbserver/win32-low.cc | 22 ++++++++-------
5 files changed, 79 insertions(+), 49 deletions(-)

diff --git a/gdb/nat/windows-nat.h b/gdb/nat/windows-nat.h
index df283646753..e63ef753c92 100644
--- a/gdb/nat/windows-nat.h
+++ b/gdb/nat/windows-nat.h
@@ -90,6 +90,27 @@ struct windows_thread_info
gdb::unique_xmalloc_ptr<char> name;
};

+
+/* Possible values to pass to 'thread_rec'. */
+enum thread_disposition_type
+{
+ /* Do not invalidate the thread's context, and do not suspend the
+ thread. */
+ DONT_INVALIDATE_CONTEXT,
+ /* Invalidate the context, but do not suspend the thread. */
+ DONT_SUSPEND,
+ /* Invalidate the context and suspend the thread. */
+ INVALIDATE_CONTEXT
+};
+
+/* Find a thread record given a thread id. THREAD_DISPOSITION
+ controls whether the thread is suspended, and whether the context
+ is invalidated.
+
+ This function must be supplied by the embedding application. */
+extern windows_thread_info *thread_rec (ptid_t ptid,
+ thread_disposition_type disposition);
+
}

#endif
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index b05a27c7cac..1192b9abac4 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -456,26 +456,13 @@ check (BOOL ok, const char *file, int line)
(unsigned) GetLastError ());
}

-/* Possible values to pass to 'thread_rec'. */
-enum thread_disposition_type
-{
- /* Do not invalidate the thread's context, and do not suspend the
- thread. */
- DONT_INVALIDATE_CONTEXT,
- /* Invalidate the context, but do not suspend the thread. */
- DONT_SUSPEND,
- /* Invalidate the context and suspend the thread. */
- INVALIDATE_CONTEXT
-};
+/* See nat/windows-nat.h. */

-/* Find a thread record given a thread id. THREAD_DISPOSITION
- controls whether the thread is suspended, and whether the context
- is invalidated. */
-static windows_thread_info *
-thread_rec (DWORD id, enum thread_disposition_type disposition)
+windows_thread_info *
+windows_nat::thread_rec (ptid_t ptid, thread_disposition_type disposition)
{
for (windows_thread_info *th : thread_list)
- if (th->tid == id)
+ if (th->tid == ptid.lwp ())
{
if (!th->suspended)
{
@@ -485,7 +472,7 @@ thread_rec (DWORD id, enum thread_disposition_type disposition)
/* Nothing. */
break;
case INVALIDATE_CONTEXT:
- if (id != current_event.dwThreadId)
+ if (ptid.lwp () != current_event.dwThreadId)
th->suspend ();
th->reload_context = true;
break;
@@ -513,13 +500,10 @@ static windows_thread_info *
windows_add_thread (ptid_t ptid, HANDLE h, void *tlb, bool main_thread_p)
{
windows_thread_info *th;
- DWORD id;

gdb_assert (ptid.lwp () != 0);

- id = ptid.lwp ();
-
- if ((th = thread_rec (id, DONT_INVALIDATE_CONTEXT)))
+ if ((th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT)))
return th;

CORE_ADDR base = (CORE_ADDR) (uintptr_t) tlb;
@@ -529,7 +513,7 @@ windows_add_thread (ptid_t ptid, HANDLE h, void *tlb, bool main_thread_p)
if (wow64_process)
base += 0x2000;
#endif
- th = new windows_thread_info (id, h, base);
+ th = new windows_thread_info (ptid.lwp (), h, base);
thread_list.push_back (th);

/* Add this new thread to the list of threads.
@@ -716,8 +700,7 @@ windows_fetch_one_register (struct regcache *regcache,
void
windows_nat_target::fetch_registers (struct regcache *regcache, int r)
{
- DWORD tid = regcache->ptid ().lwp ();
- windows_thread_info *th = thread_rec (tid, INVALIDATE_CONTEXT);
+ windows_thread_info *th = thread_rec (regcache->ptid (), INVALIDATE_CONTEXT);

/* Check if TH exists. Windows sometimes uses a non-existent
thread id in its events. */
@@ -812,8 +795,7 @@ windows_store_one_register (const struct regcache *regcache,
void
windows_nat_target::store_registers (struct regcache *regcache, int r)
{
- DWORD tid = regcache->ptid ().lwp ();
- windows_thread_info *th = thread_rec (tid, INVALIDATE_CONTEXT);
+ windows_thread_info *th = thread_rec (regcache->ptid (), INVALIDATE_CONTEXT);

/* Check if TH exists. Windows sometimes uses a non-existent
thread id in its events. */
@@ -1353,7 +1335,8 @@ handle_exception (struct target_waitstatus *ourstatus)
ourstatus->kind = TARGET_WAITKIND_STOPPED;

/* Record the context of the current thread. */
- thread_rec (current_event.dwThreadId, DONT_SUSPEND);
+ thread_rec (ptid_t (current_event.dwProcessId, current_event.dwThreadId, 0),
+ DONT_SUSPEND);

switch (code)
{
@@ -1483,7 +1466,9 @@ handle_exception (struct target_waitstatus *ourstatus)
if (named_thread_id == (DWORD) -1)
named_thread_id = current_event.dwThreadId;

- named_thread = thread_rec (named_thread_id, DONT_INVALIDATE_CONTEXT);
+ named_thread = thread_rec (ptid_t (current_event.dwProcessId,
+ named_thread_id, 0),
+ DONT_INVALIDATE_CONTEXT);
if (named_thread != NULL)
{
int thread_name_len;
@@ -1714,7 +1699,7 @@ windows_nat_target::resume (ptid_t ptid, int step, enum gdb_signal sig)
ptid.pid (), (unsigned) ptid.lwp (), step, sig));

/* Get context for currently selected thread. */
- th = thread_rec (inferior_ptid.lwp (), DONT_INVALIDATE_CONTEXT);
+ th = thread_rec (inferior_ptid, DONT_INVALIDATE_CONTEXT);
if (th)
{
#ifdef __x86_64__
@@ -1847,7 +1832,7 @@ windows_nat_target::get_windows_debug_event (int pid,
current_event = iter->event;

inferior_ptid = ptid_t (current_event.dwProcessId, thread_id, 0);
- current_thread = thread_rec (thread_id, INVALIDATE_CONTEXT);
+ current_thread = thread_rec (inferior_ptid, INVALIDATE_CONTEXT);
current_thread->reload_context = 1;

DEBUG_EVENTS (("get_windows_debug_event - "
@@ -2060,7 +2045,8 @@ windows_nat_target::get_windows_debug_event (int pid,
== EXCEPTION_BREAKPOINT)
&& windows_initialization_done)
{
- th = thread_rec (thread_id, INVALIDATE_CONTEXT);
+ ptid_t ptid = ptid_t (current_event.dwProcessId, thread_id, 0);
+ th = thread_rec (ptid, INVALIDATE_CONTEXT);
th->stopped_at_software_breakpoint = true;
}
pending_stops.push_back ({thread_id, *ourstatus, current_event});
@@ -2072,7 +2058,7 @@ windows_nat_target::get_windows_debug_event (int pid,
inferior_ptid = ptid_t (current_event.dwProcessId, thread_id, 0);
current_thread = th;
if (!current_thread)
- current_thread = thread_rec (thread_id, INVALIDATE_CONTEXT);
+ current_thread = thread_rec (inferior_ptid, INVALIDATE_CONTEXT);
}

out:
@@ -3505,7 +3491,7 @@ windows_nat_target::get_tib_address (ptid_t ptid, CORE_ADDR *addr)
{
windows_thread_info *th;

- th = thread_rec (ptid.lwp (), DONT_INVALIDATE_CONTEXT);
+ th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT);
if (th == NULL)
return false;

@@ -3526,7 +3512,7 @@ windows_nat_target::get_ada_task_ptid (long lwp, long thread)
const char *
windows_nat_target::thread_name (struct thread_info *thr)
{
- return thread_rec (thr->ptid.lwp (), DONT_INVALIDATE_CONTEXT)->name.get ();
+ return thread_rec (thr->ptid, DONT_INVALIDATE_CONTEXT)->name.get ();
}

@@ -3685,12 +3671,9 @@ cygwin_get_dr7 (void)
bool
windows_nat_target::thread_alive (ptid_t ptid)
{
- int tid;
-
gdb_assert (ptid.lwp () != 0);
- tid = ptid.lwp ();

- return (WaitForSingleObject (thread_rec (tid, DONT_INVALIDATE_CONTEXT)->h, 0)
+ return (WaitForSingleObject (thread_rec (ptid, DONT_INVALIDATE_CONTEXT)->h, 0)
!= WAIT_OBJECT_0);
}

diff --git a/gdbserver/win32-low.cc b/gdbserver/win32-low.cc
index 8f8b6cedd28..1e86b3b5926 100644
--- a/gdbserver/win32-low.cc
+++ b/gdbserver/win32-low.cc
@@ -178,17 +178,17 @@ win32_require_context (windows_thread_info *th)
}
}

-/* Find a thread record given a thread id. If GET_CONTEXT is set then
- also retrieve the context for this thread. */
-static windows_thread_info *
-thread_rec (ptid_t ptid, int get_context)
+/* See nat/windows-nat.h. */
+
+windows_thread_info *
+windows_nat::thread_rec (ptid_t ptid, thread_disposition_type disposition)
{
thread_info *thread = find_thread_ptid (ptid);
if (thread == NULL)
return NULL;

windows_thread_info *th = (windows_thread_info *) thread_target_data (thread);
- if (get_context)
+ if (disposition != DONT_INVALIDATE_CONTEXT)
win32_require_context (th);
return th;
}
@@ -200,7 +200,7 @@ child_add_thread (DWORD pid, DWORD tid, HANDLE h, void *tlb)
windows_thread_info *th;
ptid_t ptid = ptid_t (pid, tid, 0);

- if ((th = thread_rec (ptid, FALSE)))
+ if ((th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT)))
return th;

th = new windows_thread_info (tid, h, (CORE_ADDR) (uintptr_t) tlb);
@@ -454,7 +454,8 @@ static void
child_fetch_inferior_registers (struct regcache *regcache, int r)
{
int regno;
- windows_thread_info *th = thread_rec (current_thread_ptid (), TRUE);
+ windows_thread_info *th = thread_rec (current_thread_ptid (),
+ INVALIDATE_CONTEXT);
if (r == -1 || r > NUM_REGS)
child_fetch_inferior_registers (regcache, NUM_REGS);
else
@@ -468,7 +469,8 @@ static void
child_store_inferior_registers (struct regcache *regcache, int r)
{
int regno;
- windows_thread_info *th = thread_rec (current_thread_ptid (), TRUE);
+ windows_thread_info *th = thread_rec (current_thread_ptid (),
+ INVALIDATE_CONTEXT);
if (r == -1 || r == 0 || r > NUM_REGS)
child_store_inferior_registers (regcache, NUM_REGS);
else
@@ -937,7 +939,7 @@ win32_process_target::resume (thread_resume *resume_info, size_t n)

/* Get context for the currently selected thread. */
ptid = debug_event_ptid (&current_event);
- th = thread_rec (ptid, FALSE);
+ th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT);
if (th)
{
win32_prepare_to_resume (th);
@@ -1807,7 +1809,7 @@ int
win32_process_target::get_tib_address (ptid_t ptid, CORE_ADDR *addr)
{
windows_thread_info *th;
- th = thread_rec (ptid, 0);
+ th = thread_rec (ptid, DONT_INVALIDATE_CONTEXT);
if (th == NULL)
return 0;
if (addr != NULL)
--
2.21.1