[RFC] Add windows Thread Information Block

["Pierre Muller" <muller@ics.u-strasbg.fr>]

  On windows operating system
each thread gets a Thread Information Block
which contains several interesting informations:
 - Current top of Structured Exception Handlers
 - Thread Variable allocations
 - Process information
 - Current limits of stack
  The last could be particularly interesting when we try to
 to figure out an optimized stack frame.
 
  When we hit a frameless function without debug information,
we could try to find up the stack a valid pair of stored (EBP,EIP)
of the outer frame having a frame pointer.
  Testing for EBP to bee within the limits given by 
  current_top_of_stack andcurrent_bottom_of_stack
would help to find correct pairs.

I only tried to implement the 32bit version of 
this until now, the 64bit version has a different layout...
More fields are available, some being version (or simulation layer)
dependent...
  The current patch adds the code to windows-nat.c
despite the fact that I added the thread_local_base field
to both windows-nat.c and gdbserver/win32-low.c.
  To be also usable for a remote gdbserver,
I would need to move that to windows-tdep.c

  But here I need advice on how to move the display_tib function
to windows-tdep.c file, as it is currently using internal information
of windows-nat.c thread_info struct.
  Also how should I handle the remote case?
Should I add a new query, something like 'qTlb'?
How should I call this from windows-tdep code?

  All comments welcomed!


Pierre Muller
Pascal language support maintainer for GDB


2009-06-26  Pierre Muller  <muller@ics.u-strasbg.fr>

	* windows-nat.c (thread_info): Add THREAD_LOCAL_BASE field.
	(windows_add_thread): Add TLB argument of type 'void *'.
	Assign TLB to new field THREAD_LOCAL_BASE of thread_info struct.
	(fake_create_process): Adapt windows_add_thread call.
	(get_windows_debug_event): Idem.
	(display_tib): New function.
	(display_current_tib): New function.
	(_initialize_windows_nat): Add 'information w32 tib' command.
	
	* gdbserver/win32-low.c (thread_info): Add THREAD_LOCAL_BASE field.
	(child_add_thread): Add TLB argument of type 'void *'.
	(get_child_debug_event): Adapt call to child_add_thread.

Index: windows-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/windows-nat.c,v
retrieving revision 1.195
diff -u -p -r1.195 windows-nat.c
--- windows-nat.c	17 Jun 2009 18:44:23 -0000	1.195
+++ windows-nat.c	25 Jun 2009 23:27:34 -0000
@@ -140,6 +140,9 @@ static int debug_registers_used;
 static void windows_stop (ptid_t);
 static int windows_thread_alive (struct target_ops *, ptid_t);
 static void windows_kill_inferior (struct target_ops *);
+static int windows_xfer_memory (CORE_ADDR memaddr, gdb_byte *our, int len,
+				int write, struct mem_attrib *mem,
+				struct target_ops *target);
 
 static void cygwin_set_dr (int i, CORE_ADDR addr);
 static void cygwin_set_dr7 (unsigned long val);
@@ -155,6 +158,7 @@ typedef struct thread_info_struct
     struct thread_info_struct *next;
     DWORD id;
     HANDLE h;
+    CORE_ADDR thread_local_base;
     char *name;
     int suspended;
     int reload_context;
@@ -165,6 +169,50 @@ thread_info;
 
 static thread_info thread_head;
 
+
+typedef struct thread_information_block
+  {
+    uint32_t current_seh;			/* %fs:0x0000 */
+    uint32_t current_top_of_stack; 		/* %fs:0x0004 */
+    uint32_t current_bottom_of_stack;		/* %fs:0x0008 */
+    uint32_t sub_system_tib;			/* %fs:0x000c */
+    uint32_t fiber_data;			/* %fs:0x0010 */
+    uint32_t arbitrary_data_slot;		/* %fs:0x0014 */
+    uint32_t linear_address_tib;		/* %fs:0x0018 */
+    uint32_t environment_pointer;		/* %fs:0x001c */
+    uint32_t process_id;			/* %fs:0x0020 */
+    uint32_t current_thread_id;			/* %fs:0x0024 */
+    uint32_t thread_local_storage;		/* %fs:0x0028 */
+    uint32_t active_rpc_handle;			/* %fs:0x002c */
+    uint32_t process_environment_block;		/* %fs:0x0030 */
+    uint32_t last_error_number;			/* %fs:0x0034 */
+  }
+thread_information;
+
+static const
+char* TIB_NAME[] =
+  {
+    " current_seh                 ",	/* %fs:0x0000 */
+    " current_top_of_stack        ", 	/* %fs:0x0004 */
+    " current_bottom_of_stack     ",	/* %fs:0x0008 */
+    " sub_system_tib              ",	/* %fs:0x000c */
+    " fiber_data                  ",	/* %fs:0x0010 */
+    " arbitrary_data_slot         ",	/* %fs:0x0014 */
+    " linear_address_tib          ",	/* %fs:0x0018 */
+    " environment_pointer         ",	/* %fs:0x001c */
+    " process_id                  ",	/* %fs:0x0020 */
+    " current_thread_id           ",	/* %fs:0x0024 */
+    " thread_local_storage        ",	/* %fs:0x0028 */
+    " active_rpc_handle           ",	/* %fs:0x002c */
+    " process_environment_block   ",	/* %fs:0x0030 */
+    " last_error_number           "	/* %fs:0x0034 */
+  };
+
+static const int
+MAX_TIB = sizeof (TIB_NAME) / sizeof (char*);
+
+
+
 /* The process and thread handles for the above context. */
 
 static DEBUG_EVENT current_event;	/* The current debug event from
@@ -284,7 +332,7 @@ thread_rec (DWORD id, int get_context)
 
 /* Add a thread to the thread list.  */
 static thread_info *
-windows_add_thread (ptid_t ptid, HANDLE h)
+windows_add_thread (ptid_t ptid, HANDLE h, void *tlb)
 {
   thread_info *th;
   DWORD id;
@@ -299,6 +347,7 @@ windows_add_thread (ptid_t ptid, HANDLE 
   th = XZALLOC (thread_info);
   th->id = id;
   th->h = h;
+  th->thread_local_base = (CORE_ADDR) (uintptr_t) tlb;
   th->next = thread_head.next;
   thread_head.next = th;
   add_thread (ptid);
@@ -984,6 +1033,57 @@ display_selectors (char * args, int from
     }
 }
 
+/* Display thread information block of a given thread.  */
+static int
+display_tib (thread_info* th)
+{
+  thread_info tib;
+
+  if (!th)
+    return 0;
+  if (th->thread_local_base)
+    {
+      if (windows_xfer_memory (th->thread_local_base, (gdb_byte *) &tib,
+			       sizeof (tib), 0, NULL, NULL))
+	{
+	  DWORD* index = (DWORD *) &tib;
+	  int i;
+	  printf_filtered ("Thread Information Block 0x%lx at 0x%8lx\n",
+			   th->id,
+			   th->thread_local_base);
+
+	  for (i = 0; i < MAX_TIB; i++)
+	    printf_filtered ("%s is 0x%08lx\n", TIB_NAME [i], index [i]);
+	}
+      else
+	return 0;
+ 
+    } 
+  return 1;  
+}
+
+/* Display thread information block of a thread specified by ARGS.
+   If ARGS is empty, display thread information block of current_thread
+   if current_thread is non NULL.
+   Otherwise ARGS is parsed and converted to a integer that should
+   be the windows ThreadID (not the internal GDB thread ID).  */
+static void
+display_current_tib (char * args, int from_tty)
+{
+  if (args)
+    {
+      thread_info* th;
+      DWORD id = (DWORD) parse_and_eval_long (args);
+      th = thread_rec (id, 1);
+      if (th)
+	display_tib (th);
+      else
+	printf_filtered ("%ld is not a valid ThreadId\n", id);
+    }
+  else if (current_thread)
+    display_tib (current_thread);
+}
+
 static struct cmd_list_element *info_w32_cmdlist = NULL;
 
 static void
@@ -1181,9 +1281,11 @@ fake_create_process (void)
       /*  We can not debug anything in that case.  */
     }
   main_thread_id = current_event.dwThreadId;
-  current_thread = windows_add_thread (ptid_build
(current_event.dwProcessId, 0,
-
current_event.dwThreadId),
-
current_event.u.CreateThread.hThread);
+  current_thread = windows_add_thread (
+		     ptid_build (current_event.dwProcessId, 0,
+				 current_event.dwThreadId),
+		     current_event.u.CreateThread.hThread,
+		     current_event.u.CreateThread.lpThreadLocalBase);
   return main_thread_id;
 }
 
@@ -1357,7 +1459,9 @@ get_windows_debug_event (struct target_o
       retval = current_event.dwThreadId;
       th = windows_add_thread (ptid_build (current_event.dwProcessId, 0,
 					 current_event.dwThreadId),
-			     current_event.u.CreateThread.hThread);
+			     current_event.u.CreateThread.hThread,
+
current_event.u.CreateThread.lpThreadLocalBase);
+
       break;
 
     case EXIT_THREAD_DEBUG_EVENT:
@@ -1390,7 +1494,8 @@ get_windows_debug_event (struct target_o
       /* Add the main thread */
       th = windows_add_thread (ptid_build (current_event.dwProcessId, 0,
 					   current_event.dwThreadId),
-			       current_event.u.CreateProcessInfo.hThread);
+	     current_event.u.CreateProcessInfo.hThread,
+	     current_event.u.CreateProcessInfo.lpThreadLocalBase);
       retval = current_event.dwThreadId;
       break;
 
@@ -2278,6 +2383,10 @@ Show whether to display kernel exception
   add_cmd ("selector", class_info, display_selectors,
 	   _("Display selectors infos."),
 	   &info_w32_cmdlist);
+  add_cmd ("tib", class_info, display_current_tib,
+	   _("Display thread information block."),
+	   &info_w32_cmdlist);
+
   add_target (&windows_ops);
   deprecated_init_ui_hook = set_windows_aliases;
 }