[PATCH v3 10/29] Change type of argument to windows-nat.c:thread_rec

Tom Tromey
2020-03-13T19:09:00Z

windows-nat.c:thread_rec accepts an integer parameter whose
interpretation depends on whether it is less than, equal to, or
greater than zero. I found this confusing at times, so this patch
replaces it with an enum instead.

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

* windows-nat.c (enum thread_disposition_type): New.
(thread_rec): Replace "get_context" parameter with "disposition";
change type.
(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.
---
gdb/ChangeLog | 12 +++++++++
gdb/windows-nat.c | 63 ++++++++++++++++++++++++++++++++---------------
2 files changed, 55 insertions(+), 20 deletions(-)

diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c
index ce83da0ff9f..cdc24ec7ebd 100644
--- a/gdb/windows-nat.c
+++ b/gdb/windows-nat.c
@@ -404,22 +404,44 @@ check (BOOL ok, const char *file, int line)
(unsigned) GetLastError ());
}

-/* Find a thread record given a thread id. If GET_CONTEXT is not 0,
- then also retrieve the context for this thread. If GET_CONTEXT is
- negative, then don't suspend the thread. */
+/* 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. */
static windows_thread_info *
-thread_rec (DWORD id, int get_context)
+thread_rec (DWORD id, enum thread_disposition_type disposition)
{
for (windows_thread_info *th : thread_list)
if (th->tid == id)
{
- if (!th->suspended && get_context)
+ if (!th->suspended)
{
- if (get_context > 0 && id != current_event.dwThreadId)
- th->suspend ();
- else if (get_context < 0)
- th->suspended = -1;
- th->reload_context = true;
+ switch (disposition)
+ {
+ case DONT_INVALIDATE_CONTEXT:
+ /* Nothing. */
+ break;
+ case INVALIDATE_CONTEXT:
+ if (id != current_event.dwThreadId)
+ th->suspend ();
+ th->reload_context = true;
+ break;
+ case DONT_SUSPEND:
+ th->reload_context = true;
+ th->suspended = -1;
+ break;
+ }
}
return th;
}
@@ -445,7 +467,7 @@ windows_add_thread (ptid_t ptid, HANDLE h, void *tlb, bool main_thread_p)

id = ptid.lwp ();

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

CORE_ADDR base = (CORE_ADDR) (uintptr_t) tlb;
@@ -617,7 +639,7 @@ void
windows_nat_target::fetch_registers (struct regcache *regcache, int r)
{
DWORD tid = regcache->ptid ().lwp ();
- windows_thread_info *th = thread_rec (tid, TRUE);
+ windows_thread_info *th = thread_rec (tid, INVALIDATE_CONTEXT);

/* Check if TH exists. Windows sometimes uses a non-existent
thread id in its events. */
@@ -713,7 +735,7 @@ void
windows_nat_target::store_registers (struct regcache *regcache, int r)
{
DWORD tid = regcache->ptid ().lwp ();
- windows_thread_info *th = thread_rec (tid, TRUE);
+ windows_thread_info *th = thread_rec (tid, INVALIDATE_CONTEXT);

/* Check if TH exists. Windows sometimes uses a non-existent
thread id in its events. */
@@ -1253,7 +1275,7 @@ handle_exception (struct target_waitstatus *ourstatus)
ourstatus->kind = TARGET_WAITKIND_STOPPED;

/* Record the context of the current thread. */
- thread_rec (current_event.dwThreadId, -1);
+ thread_rec (current_event.dwThreadId, DONT_SUSPEND);

switch (code)
{
@@ -1383,7 +1405,7 @@ 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, 0);
+ named_thread = thread_rec (named_thread_id, DONT_INVALIDATE_CONTEXT);
if (named_thread != NULL)
{
int thread_name_len;
@@ -1588,7 +1610,7 @@ 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 (), FALSE);
+ th = thread_rec (inferior_ptid.lwp (), DONT_INVALIDATE_CONTEXT);
if (th)
{
#ifdef __x86_64__
@@ -1888,7 +1910,7 @@ 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, TRUE);
+ current_thread = thread_rec (thread_id, INVALIDATE_CONTEXT);
}

out:
@@ -3307,7 +3329,7 @@ windows_nat_target::get_tib_address (ptid_t ptid, CORE_ADDR *addr)
{
windows_thread_info *th;

- th = thread_rec (ptid.lwp (), 0);
+ th = thread_rec (ptid.lwp (), DONT_INVALIDATE_CONTEXT);
if (th == NULL)
return false;

@@ -3328,7 +3350,7 @@ 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 (), 0)->name.get ();
+ return thread_rec (thr->ptid.lwp (), DONT_INVALIDATE_CONTEXT)->name.get ();
}

@@ -3492,7 +3514,8 @@ windows_nat_target::thread_alive (ptid_t ptid)
gdb_assert (ptid.lwp () != 0);
tid = ptid.lwp ();

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

void _initialize_check_for_gdb_ini ();
--
2.21.1