gdb: use intrusive_list for linux-nat lwp_list

Replace the manually maintained linked list of lwp_info objects with
intrusive_list.  Replace the ALL_LWPS macro with all_lwps, which returns
a range.  Add all_lwps_safe as well, for use in iterate_over_lwps, which
currently iterates in a safe manner.

Change-Id: I355313502510acc0103f5eaf2fbde80897d6376c
This commit is contained in:
Simon Marchi 2021-08-28 10:58:45 -04:00
parent 676362df18
commit 901b98215e
5 changed files with 46 additions and 53 deletions

View File

@ -589,7 +589,6 @@ ia64_linux_nat_target::insert_watchpoint (CORE_ADDR addr, int len,
enum target_hw_bp_type type,
struct expression *cond)
{
struct lwp_info *lp;
int idx;
long dbr_addr, dbr_mask;
int max_watchpoints = 4;
@ -630,7 +629,8 @@ ia64_linux_nat_target::insert_watchpoint (CORE_ADDR addr, int len,
debug_registers[2 * idx] = dbr_addr;
debug_registers[2 * idx + 1] = dbr_mask;
ALL_LWPS (lp)
for (const lwp_info *lp : all_lwps ())
{
store_debug_register_pair (lp->ptid, idx, &dbr_addr, &dbr_mask);
enable_watchpoints_in_psr (lp->ptid);
@ -657,14 +657,12 @@ ia64_linux_nat_target::remove_watchpoint (CORE_ADDR addr, int len,
dbr_mask = debug_registers[2 * idx + 1];
if ((dbr_mask & (0x3UL << 62)) && addr == (CORE_ADDR) dbr_addr)
{
struct lwp_info *lp;
debug_registers[2 * idx] = 0;
debug_registers[2 * idx + 1] = 0;
dbr_addr = 0;
dbr_mask = 0;
ALL_LWPS (lp)
for (const lwp_info *lp : all_lwps ())
store_debug_register_pair (lp->ptid, idx, &dbr_addr, &dbr_mask);
return 0;

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@ -421,9 +421,8 @@ static int
num_lwps (int pid)
{
int count = 0;
struct lwp_info *lp;
for (lp = lwp_list; lp; lp = lp->next)
for (const lwp_info *lp ATTRIBUTE_UNUSED : all_lwps ())
if (lp->ptid.pid () == pid)
count++;
@ -700,17 +699,31 @@ lwp_lwpid_htab_add_lwp (struct lwp_info *lp)
creation order. This order is assumed in some cases. E.g.,
reaping status after killing alls lwps of a process: the leader LWP
must be reaped last. */
struct lwp_info *lwp_list;
static intrusive_list<lwp_info> lwp_list;
/* See linux-nat.h. */
lwp_info_range
all_lwps ()
{
return lwp_info_range (lwp_list.begin ());
}
/* See linux-nat.h. */
lwp_info_safe_range
all_lwps_safe ()
{
return lwp_info_safe_range (lwp_list.begin ());
}
/* Add LP to sorted-by-reverse-creation-order doubly-linked list. */
static void
lwp_list_add (struct lwp_info *lp)
{
lp->next = lwp_list;
if (lwp_list != NULL)
lwp_list->prev = lp;
lwp_list = lp;
lwp_list.push_front (*lp);
}
/* Remove LP from sorted-by-reverse-creation-order doubly-linked
@ -720,12 +733,7 @@ static void
lwp_list_remove (struct lwp_info *lp)
{
/* Remove from sorted-by-creation-order list. */
if (lp->next != NULL)
lp->next->prev = lp->prev;
if (lp->prev != NULL)
lp->prev->next = lp->next;
if (lp == lwp_list)
lwp_list = lp->next;
lwp_list.erase (lwp_list.iterator_to (*lp));
}
@ -922,12 +930,8 @@ struct lwp_info *
iterate_over_lwps (ptid_t filter,
gdb::function_view<iterate_over_lwps_ftype> callback)
{
struct lwp_info *lp, *lpnext;
for (lp = lwp_list; lp; lp = lpnext)
for (lwp_info *lp : all_lwps_safe ())
{
lpnext = lp->next;
if (lp->ptid.matches (filter))
{
if (callback (lp) != 0)
@ -3715,8 +3719,6 @@ linux_nat_target::thread_alive (ptid_t ptid)
void
linux_nat_target::update_thread_list ()
{
struct lwp_info *lwp;
/* We add/delete threads from the list as clone/exit events are
processed, so just try deleting exited threads still in the
thread list. */
@ -3724,7 +3726,7 @@ linux_nat_target::update_thread_list ()
/* Update the processor core that each lwp/thread was last seen
running on. */
ALL_LWPS (lwp)
for (lwp_info *lwp : all_lwps ())
{
/* Avoid accessing /proc if the thread hasn't run since we last
time we fetched the thread's core. Accessing /proc becomes
@ -3948,7 +3950,7 @@ linux_proc_xfer_memory_partial (gdb_byte *readbuf, const gdb_byte *writebuf,
/* Iterate over LWPs of the current inferior, trying to access
memory through one of them. */
for (lwp_info *lp = lwp_list; lp != nullptr; lp = lp->next)
for (lwp_info *lp : all_lwps ())
{
if (lp->ptid.pid () != cur_pid)
continue;

View File

@ -196,11 +196,9 @@ extern linux_nat_target *linux_target;
struct arch_lwp_info;
/* Structure describing an LWP. This is public only for the purposes
of ALL_LWPS; target-specific code should generally not access it
directly. */
/* Structure describing an LWP. */
struct lwp_info
struct lwp_info : intrusive_list_node<lwp_info>
{
lwp_info (ptid_t ptid)
: ptid (ptid)
@ -283,27 +281,26 @@ struct lwp_info
/* Arch-specific additions. */
struct arch_lwp_info *arch_private = nullptr;
/* Previous and next pointers in doubly-linked list of known LWPs,
sorted by reverse creation order. */
struct lwp_info *prev = nullptr;
struct lwp_info *next = nullptr;
};
/* The global list of LWPs, for ALL_LWPS. Unlike the threads list,
there is always at least one LWP on the list while the GNU/Linux
native target is active. */
extern struct lwp_info *lwp_list;
/* lwp_info iterator and range types. */
using lwp_info_iterator
= reference_to_pointer_iterator<intrusive_list<lwp_info>::iterator>;
using lwp_info_range = iterator_range<lwp_info_iterator>;
using lwp_info_safe_range = basic_safe_range<lwp_info_range>;
/* Get an iterable range over all lwps. */
lwp_info_range all_lwps ();
/* Same as the above, but safe against deletion while iterating. */
lwp_info_safe_range all_lwps_safe ();
/* Does the current host support PTRACE_GETREGSET? */
extern enum tribool have_ptrace_getregset;
/* Iterate over each active thread (light-weight process). */
#define ALL_LWPS(LP) \
for ((LP) = lwp_list; \
(LP) != NULL; \
(LP) = (LP)->next)
/* Called from the LWP layer to inform the thread_db layer that PARENT
spawned CHILD. Both LWPs are currently stopped. This function
does whatever is required to have the child LWP under the

View File

@ -920,13 +920,12 @@ try_thread_db_load_1 (struct thread_db_info *info)
if (info->td_ta_thr_iter_p == NULL)
{
struct lwp_info *lp;
int pid = inferior_ptid.pid ();
thread_info *curr_thread = inferior_thread ();
linux_stop_and_wait_all_lwps ();
ALL_LWPS (lp)
for (const lwp_info *lp : all_lwps ())
if (lp->ptid.pid () == pid)
thread_from_lwp (curr_thread, lp->ptid);

View File

@ -632,12 +632,9 @@ mips_linux_nat_target::region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
static int
write_watchpoint_regs (void)
{
struct lwp_info *lp;
int tid;
ALL_LWPS (lp)
for (const lwp_info *lp : all_lwps ())
{
tid = lp->ptid.lwp ();
int tid = lp->ptid.lwp ();
if (ptrace (PTRACE_SET_WATCH_REGS, tid, &watch_mirror, NULL) == -1)
perror_with_name (_("Couldn't write debug register"));
}