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Handle case where Ada task is current but not listed

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Currently, the ravenscar runtime can mark an Ada task as the current
task, before adding it to the list of tasks that can be read by gdb.
In this scenario, gdb can sometimes crash in
ravenscar_get_thread_base_cpu with:

../../src/gdb/ravenscar-thread.c:167: internal-error: int ravenscar_get_thread_base_cpu(ptid_t): Assertion `task_info != NULL' failed.

However, as ravenscar_get_thread_base_cpu is only called to find the
base CPU, we can simply record this when registering the thread, and
look this up later.

gdb/ChangeLog
2020-08-07  Tom Tromey  <tromey@adacore.com>

	* ravenscar-thread.c (ravenscar_thread_target) <get_base_cpu,
	get_base_thread_from_ravenscar_task>: Now methods.
	<m_cpu_map>: New member.
	(ravenscar_thread_target::get_thread_base_cpu): Rename from
	ravenscar_get_thread_base_cpu.  Check m_cpu_map.
	(ravenscar_thread_target::task_is_currently_active): Update.
	(ravenscar_thread_target::get_base_thread_from_ravenscar_task):
	Now a method.
	(ravenscar_thread_target::add_active_thread): Put initial thread
	into the m_cpu_map.
This commit is contained in:
Tom Tromey 2020-08-07 10:26:45 -06:00
parent 550ab58d6e
commit a8ac85bb7d
2 changed files with 42 additions and 11 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
gdb/ChangeLog
View file

@ -1,3 +1,16 @@
2020-08-07 Tom Tromey <tromey@adacore.com>
* ravenscar-thread.c (ravenscar_thread_target) <get_base_cpu,
get_base_thread_from_ravenscar_task>: Now methods.
<m_cpu_map>: New member.
(ravenscar_thread_target::get_thread_base_cpu): Rename from
ravenscar_get_thread_base_cpu. Check m_cpu_map.
(ravenscar_thread_target::task_is_currently_active): Update.
(ravenscar_thread_target::get_base_thread_from_ravenscar_task):
Now a method.
(ravenscar_thread_target::add_active_thread): Put initial thread
into the m_cpu_map.
2020-08-07 Tom Tromey <tromey@adacore.com>
* ravenscar-thread.c (ravenscar_thread_target::wait): Return

40
gdb/ravenscar-thread.c
View file

@ -30,6 +30,7 @@
#include "top.h"
#include "regcache.h"
#include "objfiles.h"
#include <unordered_map>
/* This module provides support for "Ravenscar" tasks (Ada) when
debugging on bare-metal targets.
@ -133,6 +134,14 @@ private:
ptid_t active_task (int cpu);
bool task_is_currently_active (ptid_t ptid);
bool runtime_initialized ();
int get_thread_base_cpu (ptid_t ptid);
ptid_t get_base_thread_from_ravenscar_task (ptid_t ptid);
/* This maps a TID to the CPU on which it was running. This is
needed because sometimes the runtime will report an active task
that hasn't yet been put on the list of tasks that is read by
ada-tasks.c. */
std::unordered_map<long, int> m_cpu_map;
};
/* Return true iff PTID corresponds to a ravenscar task. */
@ -156,8 +165,8 @@ is_ravenscar_task (ptid_t ptid)
This assume that PTID is a valid ptid_t. Otherwise, a gdb_assert
will be triggered. */
static int
ravenscar_get_thread_base_cpu (ptid_t ptid)
int
ravenscar_thread_target::get_thread_base_cpu (ptid_t ptid)
{
int base_cpu;
@ -165,8 +174,15 @@ ravenscar_get_thread_base_cpu (ptid_t ptid)
{
struct ada_task_info *task_info = ada_get_task_info_from_ptid (ptid);
gdb_assert (task_info != NULL);
base_cpu = task_info->base_cpu;
if (task_info != NULL)
base_cpu = task_info->base_cpu;
else
{
auto iter = m_cpu_map.find (ptid.tid ());
gdb_assert (iter != m_cpu_map.end ());
base_cpu = iter->second;
}
}
else
{
@ -190,8 +206,7 @@ ravenscar_get_thread_base_cpu (ptid_t ptid)
bool
ravenscar_thread_target::task_is_currently_active (ptid_t ptid)
{
ptid_t active_task_ptid
= active_task (ravenscar_get_thread_base_cpu (ptid));
ptid_t active_task_ptid = active_task (get_thread_base_cpu (ptid));
return ptid == active_task_ptid;
}
@ -202,15 +217,15 @@ ravenscar_thread_target::task_is_currently_active (ptid_t ptid)
This is the thread that corresponds to the CPU on which the task
is running. */
static ptid_t
get_base_thread_from_ravenscar_task (ptid_t ptid)
ptid_t
ravenscar_thread_target::get_base_thread_from_ravenscar_task (ptid_t ptid)
{
int base_cpu;
if (!is_ravenscar_task (ptid))
return ptid;
base_cpu = ravenscar_get_thread_base_cpu (ptid);
base_cpu = get_thread_base_cpu (ptid);
return ptid_t (ptid.pid (), base_cpu, 0);
}
@ -227,7 +242,7 @@ ravenscar_thread_target::add_active_thread ()
int base_cpu;
gdb_assert (!is_ravenscar_task (m_base_ptid));
base_cpu = ravenscar_get_thread_base_cpu (m_base_ptid);
base_cpu = get_thread_base_cpu (m_base_ptid);
if (!runtime_initialized ())
return nullptr;
@ -242,7 +257,10 @@ ravenscar_thread_target::add_active_thread ()
may not always add it to the thread list. Add it here. */
thread_info *active_thr = find_thread_ptid (proc_target, active_ptid);
if (active_thr == nullptr)
active_thr = add_thread (proc_target, active_ptid);
{
active_thr = ::add_thread (proc_target, active_ptid);
m_cpu_map[active_ptid.tid ()] = base_cpu;
}
return active_thr;
}