[RFC-v6] Add windows OS Thread Information Block

["Pierre Muller" <pierre dot muller at ics-cnrs dot unistra dot fr>]

  I will try to answer all points that you raised:
> Uppercasing variables names is for talking about a
> variable's _value_, not name:
> 
> http://www.gnu.org/prep/standards/standards.html#Comments:
> 
>  "The variable name itself should be lower case, but write it in upper
> case
>  when you are speaking about the value rather than the variable itself.
> Thus,
>  âthe inode number NODE_NUMâ rather than âan inodeâ."

  Thanks for this information.
> >
> >
> > doc/ChangeLog entry:
> >
> > 	gdb.texinfo ($__tlb): Document new automatic convience variable.
> > 	(info w32 thread-information-block): Docmuent new command.
> > 	(qGetTIBAddress): Document new gdbserver query.
> > 	(maint set/show show-all-tib): Document new command.
> 
> Typos: convience, Docmuent

 Fixed.
> >
> > Index: remote.c
> > +/* Provide thread local base, i.e. Thread Information Block address.
> */
> > +/* Returns 1 if ptid is found and thread_local_base is non zero.  */
> > +int
> 
> Merge both comments in a single /**/ block.  Please add an empty
> line between comment and function (everywhere).
  Done. 
> (&remote_protocol_packets[PACKET_qGetTIBAddr],
> > +			 "qGetTIBAddr",
> > "get-thread-information-block-address",
> > +			 0);
> > +
> 
> It looks like the patch got line-wrap mangled here, and
> in several other places.  Could you make sure line-wrapping
> is disabled when you paste patches in the email?  Thanks.

  I will try to be more careful.
 
> > Index: target.h
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/target.h,v
> > retrieving revision 1.177
> > diff -u -p -r1.177 target.h
> > --- target.h	24 Mar 2010 01:12:13 -0000	1.177
> > +++ target.h	1 Apr 2010 12:46:45 -0000
> > @@ -682,6 +682,10 @@ struct target_ops
> >      int (*to_verify_memory) (struct target_ops *, const gdb_byte
> *data,
> >  			     CORE_ADDR memaddr, ULONGEST size);
> >
> > +    /* Return the address of the start of the Thread Information
> Block
> > +       a windows OS specific feature.  */
> 
> Windows.

 Corrected.
> > Index: windows-nat.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/windows-nat.c,v
> > retrieving revision 1.207
> > diff -u -p -r1.207 windows-nat.c
> > --- windows-nat.c	10 Mar 2010 15:57:07 -0000	1.207
> > +++ windows-nat.c	1 Apr 2010 12:46:45 -0000
> > +/* Returns 1 if ptid is found and thread_local_base is non zero.  */
> > +int
> 
> Same here regarding the /**/ merging, and empty line missing.


 
> > +windows_get_tib_address (ptid_t ptid, CORE_ADDR *addr)
> > +{
> > +  thread_info *th;
> > +
> > +  th = thread_rec (ptid_get_tid (ptid), 0);
> > +  if (th == NULL)
> > +    return 0;
> > +
> > +  if (addr)
> > +    {
> > +      *addr = (CORE_ADDR) th->thread_local_base;
> > +    }
> 
> One line statements don't get a wrapped in {}, just
> like you have correctly done above.
  Corrected.
> Drop the cast, as the new thread_local_base field is already
> a CORE_ADDR.  
  This was probably a left over from earlier versions
for which thread_local_base was of ULONGEST type, suppressed.
> In one case, you've checked a pointer
> against NULL, and in the other you haven't.  Please
> make this all consistent:
> 
>   if (addr != NULL)
>     *addr = th->thread_local_base;
> 
> > +  if (th->thread_local_base)
> > +    return 1;
> 
> Style wise, it looks strange to fill *addr even when
> th->thread_local_base would be 0, and hence you'd return
> 0 below.
> 
> > +  return 0;
> > +}
> 
> Here's what I'd suggest:
> 
>   th = thread_rec (ptid_get_tid (ptid), 0);
>   if (th == NULL || th->thread_local_base == 0)
>     return 0;
> 
>   if (addr != NULL)
>     *addr = th->thread_local_base;
> 
>   return 1;

  Seems good to me, as I anyhow don't think that
Windows OS will ever use '0' as a Thread Information Block address.
Note that this is only a guess, but it might be required 
if Windows OS guarantees that the null address is not accessible,
but I don't know if this is indeed written somewhere in the specs. 
 
  I was just wondering why I made this function global,
and as I saw no reason, I made it static.
 
> > Index: windows-tdep.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/windows-tdep.c,v
> > retrieving revision 1.5
> > diff -u -p -r1.5 windows-tdep.c
> > --- windows-tdep.c	1 Jan 2010 07:31:46 -0000	1.5
> > +++ windows-tdep.c	1 Apr 2010 12:46:45 -0000
> > @@ -19,6 +19,372 @@
> >  #include "windows-tdep.h"
> >  #include "gdb_obstack.h"
> >  #include "xml-support.h"
> > +#include "gdbarch.h"
> > +#include "target.h"
> > +#include "value.h"
> > +#include "inferior.h"
> > +#include "command.h"
> > +#include "gdbcmd.h"
> > +#include "gdbthread.h"
> > +
> > +struct cmd_list_element *info_w32_cmdlist;
> > +
> > +typedef struct thread_information_block_32
> > +  {
> > +    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 active_rpc_handle;			/* %fs:0x0028 */
> > +    uint32_t thread_local_storage;		/* %fs:0x002c */
> > +    uint32_t process_environment_block;		/* %fs:0x0030 */
> > +    uint32_t last_error_number;			/* %fs:0x0034 */
> > +  }
> > +thread_information_32;
> > +
> > +typedef struct thread_information_block_64
> > +  {
> > +    uint64_t current_seh;			/* %gs:0x0000 */
> > +    uint64_t current_top_of_stack; 		/* %gs:0x0008 */
> > +    uint64_t current_bottom_of_stack;		/* %gs:0x0010 */
> > +    uint64_t sub_system_tib;			/* %gs:0x0018 */
> > +    uint64_t fiber_data;			/* %gs:0x0020 */
> > +    uint64_t arbitrary_data_slot;		/* %gs:0x0028 */
> > +    uint64_t linear_address_tib;		/* %gs:0x0030 */
> > +    uint64_t environment_pointer;		/* %gs:0x0038 */
> > +    uint64_t process_id;			/* %gs:0x0040 */
> > +    uint64_t current_thread_id;			/* %gs:0x0048 */
> > +    uint64_t active_rpc_handle;			/* %gs:0x0050 */
> > +    uint64_t thread_local_storage;		/* %gs:0x0058 */
> > +    uint64_t process_environment_block;		/* %gs:0x0060 */
> > +    uint64_t last_error_number;			/* %gs:0x0068 */
> > +  }
> > +thread_information_64;
> > +
> > +
> > +static const
> > +char* TIB_NAME[] =
> 
> 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 */
> > +    " active_rpc_handle           ",	/* %fs:0x0028 */
> > +    " thread_local_storage        ",	/* %fs:0x002c */
> > +    " process_environment_block   ",	/* %fs:0x0030 */
> > +    " last_error_number           "	/* %fs:0x0034 */
> > +  };
> > +
> > +static const int
> > +MAX_TIB32 = sizeof (thread_information_32) / sizeof (uint32_t);
> > +static const int
> > +MAX_TIB64 = sizeof (thread_information_64) / sizeof (uint64_t);
> > +static const int
> > +FULL_TIB_SIZE = 0x1000;
> 
> Only functions need a line break before the function name.

  Again, I show my lack of knowledge about C formatting :(
 
> > +
> > +static int maint_display_all_tib = 0;
> > +
> > +/* Define ThreadLocalBase pointer type */
> 
> Missing period.  Two spaces after period.  Empty line between comment
> and function.
 Corrected.
> > +struct type *
> > +windows_get_tlb_type (struct gdbarch *gdbarch)
> > +
> > +  /* struct _PEB_LDR_DATA */
> > +  /* FIXME: 64bit layout is unknown.  */
> 
> Is this still unknown?
  I tested it on one particular 64-bit Windows OS, 
for which it seemed to give reasonable values...
I removed the FIXME.
 
> > +  peb_ldr_type = arch_composite_type (gdbarch, NULL,
> TYPE_CODE_STRUCT);
> > +  TYPE_NAME (peb_ldr_type) = xstrdup ("peb_ldr_data");
> > +
> > +  append_composite_type_field (peb_ldr_type, "length",
> dword32_type);
> > +  append_composite_type_field (peb_ldr_type, "initialized",
> dword32_type);
> > +  append_composite_type_field (peb_ldr_type, "ss_handle",
> void_ptr_type);
> > +  append_composite_type_field (peb_ldr_type, "in_load_order",
> list_type);
> > +  append_composite_type_field (peb_ldr_type, "in_memory_order",
> list_type);
> > +  append_composite_type_field (peb_ldr_type, "in_init_order",
> list_type);
> > +  append_composite_type_field (peb_ldr_type, "entry_in_progress",
> > +			       void_ptr_type);
> > +  peb_ldr_ptr_type = arch_type (gdbarch, TYPE_CODE_PTR,
> > +			    TYPE_LENGTH (void_ptr_type), NULL);
> > +  TYPE_TARGET_TYPE (peb_ldr_ptr_type) = peb_ldr_type;
> > +
> > +
> > +  /* struct process environment block */
> > +  peb_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
> > +  TYPE_NAME (peb_type) = xstrdup ("peb");
> > +
> > +  /* 4 first byte contain several flags.  */
> > +  /* FIXME: 64bit layout is unknown.  */
> > +  append_composite_type_field (peb_type, "flags", dword_ptr_type);
> > +  append_composite_type_field (peb_type, "mutant", void_ptr_type);
> > +  append_composite_type_field (peb_type, "image_base_address",
> > void_ptr_type);
> > +  append_composite_type_field (peb_type, "ldr", peb_ldr_ptr_type);
> > +  append_composite_type_field (peb_type, "process_parameters",
> > void_ptr_type);
> > +  append_composite_type_field (peb_type, "sub_system_data",
> void_ptr_type);
> > +  append_composite_type_field (peb_type, "process_heap",
> void_ptr_type);
> > +  append_composite_type_field (peb_type, "fast_peb_lock",
> void_ptr_type);
> > +  peb_ptr_type = arch_type (gdbarch, TYPE_CODE_PTR,
> > +			    TYPE_LENGTH (void_ptr_type), NULL);
> > +  TYPE_TARGET_TYPE (peb_ptr_type) = peb_type;
> > +
> > +
> > +  /* struct thread information block */
> > +  tib_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
> > +  TYPE_NAME (tib_type) = xstrdup ("tib");
> > +
> > +  /* uint32_t current_seh;			%fs:0x0000 */
> > +  append_composite_type_field (tib_type, "current_seh",
> seh_ptr_type);
> > +  /* uint32_t current_top_of_stack; 		%fs:0x0004 */
> > +  append_composite_type_field (tib_type, "current_top_of_stack",
> > void_ptr_type);
> > +  /* uint32_t current_bottom_of_stack;		%fs:0x0008 */
> > +  append_composite_type_field (tib_type, "current_bottom_of_stack",
> > +			       void_ptr_type);
> > +  /* uint32_t sub_system_tib;			%fs:0x000c */
> > +  append_composite_type_field (tib_type, "sub_system_tib",
> void_ptr_type);
> > +
> > +  /* uint32_t fiber_data;			%fs:0x0010 */
> > +  append_composite_type_field (tib_type, "fiber_data",
> void_ptr_type);
> > +  /* uint32_t arbitrary_data_slot;		%fs:0x0014 */
> > +  append_composite_type_field (tib_type, "arbitrary_data_slot",
> > void_ptr_type);
> > +  /* uint32_t linear_address_tib;		%fs:0x0018 */
> > +  append_composite_type_field (tib_type, "linear_address_tib",
> > void_ptr_type);
> > +  /* uint32_t environment_pointer;		%fs:0x001c */
> > +  append_composite_type_field (tib_type, "environment_pointer",
> > void_ptr_type);
> > +  /* uint32_t process_id;			%fs:0x0020 */
> > +  append_composite_type_field (tib_type, "process_id",
> dword_ptr_type);
> > +  /* uint32_t current_thread_id;		%fs:0x0024 */
> > +  append_composite_type_field (tib_type, "thread_id",
> dword_ptr_type);
> > +  /* uint32_t active_rpc_handle;		%fs:0x0028 */
> > +  append_composite_type_field (tib_type, "active_rpc_handle",
> > dword_ptr_type);
> > +  /* uint32_t thread_local_storage;		%fs:0x002c */
> > +  append_composite_type_field (tib_type, "thread_local_storage",
> > void_ptr_type);
> > +  /* uint32_t process_environment_block;	%fs:0x0030 */
> > +  append_composite_type_field (tib_type,
> "process_environment_block",
> > +			       peb_ptr_type);
> > +  /* uint32_t last_error_number;		%fs:0x0034 */
> > +  append_composite_type_field (tib_type, "last_error_number",
> > dword_ptr_type);
> > +
> > +  tib_ptr_type = arch_type (gdbarch, TYPE_CODE_PTR,
> > +			    TYPE_LENGTH (void_ptr_type), NULL);
> > +  TYPE_TARGET_TYPE (tib_ptr_type) = tib_type;
> > +
> > +  return tib_ptr_type;
> > +}
> > +/* The $_tlb convenience variable is a bit special.  We don't know
> > +   for sure the type of the value until we actually have a chance to
> > +   fetch the data.  The type can change depending on gdbarch, so it
> it
> > +   also dependent on which thread you have selected.
> > +
> > +     1. making $_tlb be an internalvar that creates a new value on
> > +     access.
> > +
> > +     2. making the value of $_tlbi be an lval_computed value.  */
> > +
> > +/* This function implements the lval_computed support for reading a
> > +   $_tlb value.  */
> > +
> > +static void
> > +tlb_value_read (struct value *val)
> > +{
> > +  CORE_ADDR tlb;
> > +  ULONGEST num;
> > +  struct type *type = check_typedef (value_type (val));
> > +  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch
> (type));
> > +  struct value *parent = value_parent (val);
> > +  LONGEST offset = value_offset (val);
> 
> What are these two for?
  I don't know, probably some copy/paste without 
re-inspection afterwards. Removed.

> > +  int length = TYPE_LENGTH (type);
> > +
> > +  /* This needs to be changed if multi-process support is added.  */
> > +
> > +  if (!target_get_tib_address (inferior_ptid, &tlb))
> > +    error (_("Unable to read tlb"));
> > +  num = (ULONGEST) tlb;
> > +  store_unsigned_integer (value_contents_raw (val), length,
> byte_order,
> > num);
> 
> This assumes `tlb' is an address, and VAL is a pointer, so, take a look
> at value_from_pointer, and try doing something similar instead:
> 
>   store_typed_address (value_contents_raw (val), type, addr);
 Changed to your proposal.
 
> > +}
> > +
> > +/* This function implements the lval_computed support for writing a
> > +   $_siginfo value.  */
> 
> Copy/paste error:  s/_siginfo/_tlb/

  Corrected.
> > +
> > +static void
> > +tlb_value_write (struct value *v, struct value *fromval)
> > +{
> > +  error (_("Impossible to change tlb"));
> > +}
> > +
> > +static struct lval_funcs tlb_value_funcs =
> > +  {
> > +    tlb_value_read,
> > +    tlb_value_write
> > +  };
> > +
> > +
> > +/* Return a new value with the correct type for the tlb object of
> > +   the current thread using architecture GDBARCH.  Return a void
> value
> > +   if there's no object available.  */
> > +
> > +static struct value *
> > +tlb_make_value (struct gdbarch *gdbarch, struct internalvar *var)
> > +{
> > +  if (target_has_stack
> > +      && !ptid_equal (inferior_ptid, null_ptid))
> > +    {
> > +      struct type *type = windows_get_tlb_type (gdbarch);
> > +      return allocate_computed_value (type, &tlb_value_funcs, NULL);
> > +    }
> > +
> > +  return allocate_value (builtin_type (gdbarch)->builtin_void);
> > +}
> > +
> > +
> > +/* Display thread information block of a given thread.  */
> > +static int
> > +display_one_tib (ptid_t ptid)
> > +{
> > +#define PTID_STRING_SIZE 40
> > +  char annex[PTID_STRING_SIZE];
> > +  char *annex_end = annex + PTID_STRING_SIZE;
> > +  gdb_byte *tib = NULL;
> > +  gdb_byte *index;
> > +  CORE_ADDR thread_local_base;
> > +  ULONGEST i, val, max, max_name, size, tib_size;
> > +  ULONGEST sizeof_ptr = gdbarch_ptr_bit (target_gdbarch);
> > +  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
> > +
> > +  if (sizeof_ptr == 64)
> > +    {
> > +      size = sizeof (uint64_t);
> > +      tib_size = sizeof (thread_information_64);
> > +      max = MAX_TIB64;
> > +    }
> > +  else
> > +    {
> > +      size = sizeof (uint32_t);
> > +      tib_size = sizeof (thread_information_32);
> > +      max = MAX_TIB32;
> > +    }
> > +
> > +  max_name = max;
> > +
> > +  if (maint_display_all_tib)
> > +    {
> > +      tib_size = FULL_TIB_SIZE;
> > +      max = tib_size / size;
> > +    }
> > +
> > +  tib = alloca (tib_size);
> > +
> > +  /* This needs to be changed if multi-process support is added.  */
> 
> What needs changing?
  I think that this is also a leftover from a previous version
in which only the Thread Id was given as parameter.
> > +
> > +  if (target_get_tib_address (ptid, &thread_local_base) == 0)
> > +    {
> > +      printf_filtered ("Unable to get thread local base for ThreadId
> %s\n",
> > +	pulongest (ptid_get_tid(ptid)));
> 
> Incomplete transition: please avoid the ptid_get_tid in common code.
  I changed it to use target_pid_to_str everywhere.
 
> > +      return -1;
> > +    }
> > +
> > +  if (target_read (&current_target, TARGET_OBJECT_MEMORY,
> > +		   annex, tib, thread_local_base, tib_size) != tib_size)
> > +    {
> > +      printf_filtered ("Unable to read thread information block for
> > ThreadId %s at address %s\n",
> > +	pulongest (ptid_get_tid (ptid)),
> > +	paddress (target_gdbarch, thread_local_base));
> 
> Same.  Missing i18n.
Fixed.
> > +      return -1;
> > +    }
> > +
> > +  printf_filtered ("Thread Information Block %s at %s\n",
> > +		   pulongest (ptid_get_tid (ptid)),
> > +		   paddress (target_gdbarch, thread_local_base));
> 
> Same.
Fixed.
> > +
> > +  index = (gdb_byte *) tib;
> > +
> > +  /* All fields have the size of a pointer, this allows to iterate
> > +     using the same for loop for both layouts.  */
> > +  for (i = 0; i < max; i++)
> > +    {
> > +      val = extract_unsigned_integer (index, size, byte_order);
> > +      if (i < max_name)
> > +	printf_filtered ("%s is 0x%s\n", TIB_NAME [i], phex (val, size));
> 
> No space in array subscripting:
> 
>  TIB_NAME[i]
 Corrected 
> > +      else if (val != 0)
> > +	printf_filtered ("TIB[0x%s] is 0x%s\n", phex (i*size, 2),
> > +			 phex (val, size));
> 
> i18n.  Spaces missing around '*'.
Corrected. 
> > Index: doc/gdb.texinfo
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
> > retrieving revision 1.692
> > diff -u -p -r1.692 gdb.texinfo
> > --- doc/gdb.texinfo	31 Mar 2010 12:19:52 -0000	1.692
> > +++ doc/gdb.texinfo	1 Apr 2010 12:46:53 -0000
> > @@ -8054,6 +8054,14 @@ The variable @code{$_siginfo} contains e
> >  (@pxref{extra signal information}).  Note that @code{$_siginfo}
> >  could be empty, if the application has not yet received any signals.
> >  For example, it will be empty before you execute the @code{run}
> command.
> > +
> > +@item $_tlb
> > +@vindex $_tlb@r{, convenience variable}
> > +The variable @code{$_tlb} is automatically set for Windows OS
> running
> > +applications in native mode or connected to a gdbserver that
> supports
> > +@code{qGetTIBAddr} requests. This variable contains the address of
> the
> > thread
> > +information block.
> 
> I don't think users would (or should) know what a qGetTIBAddr request
> is, or how to check if their gdbserver supports it.
Eli was OK for this with a reference to 'General query packets'
which I added.
 
> > +
> >  @end table
> >
> >  On HP-UX systems, if you refer to a function or variable name that
> > @@ -15729,6 +15737,10 @@ are:
> >  @tab @code{qGetTLSAddr}
> >  @tab Displaying @code{__thread} variables
> >
> > +@item @code{w32 thread-information-block}
> > +@tab @code{qGetTIBAddr}
> > +@tab Display Windows OS Thread Information Block.
> > +
> >  @item @code{search-memory}
> >  @tab @code{qSearch:memory}
> >  @tab @code{find}
> > @@ -16508,6 +16520,11 @@ a long value to give the information abo
> >  Without argument, this command displays information
> >  about the six segment registers.
> >
> > +@item info w32 thread-information-block
> > +This command displays thread specific information stored in the
> > +Thread Information Block (readable using @code{$fs} selector for 32-
> bit
> > +programs and @code{$gs} for 64-bit programs).
> 
> This implies x86; ARM Windows CE programs are also 32-bit, but that
> comment would apply.

You are right, this only applies to x86 CPU family.
Another question is if this is supported by Windows-CE running on i386.
Apparently, The Windows CE API also has this
lpThreadLocalBase field in the CREATE_PROCESS_DEBUG_INFO
structure, but I have no idea about the layout of
the Thread Information Block for Windows CE.

> > Index: gdbserver/win32-low.c
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/gdbserver/win32-low.c,v
> > retrieving revision 1.43
> > diff -u -p -r1.43 win32-low.c
> > --- gdbserver/win32-low.c	20 Jan 2010 22:55:38 -0000	1.43
> > +++ gdbserver/win32-low.c	1 Apr 2010 12:46:54 -0000
> > @@ -178,7 +178,7 @@ thread_rec (ptid_t ptid, int get_context
> >
> >  /* Add a thread to the thread list.  */
> >  static win32_thread_info *
> > -child_add_thread (DWORD pid, DWORD tid, HANDLE h)
> > +child_add_thread (DWORD pid, DWORD tid, HANDLE h, void *tlb)
> >  {
> >    win32_thread_info *th;
> >    ptid_t ptid = ptid_build (pid, tid, 0);
> > @@ -189,6 +189,7 @@ child_add_thread (DWORD pid, DWORD tid,
> >    th = xcalloc (1, sizeof (*th));
> >    th->tid = tid;
> >    th->h = h;
> > +  th->thread_local_base = (CORE_ADDR) (uintptr_t) tlb;
> >
> >    add_thread (ptid, th);
> >    set_inferior_regcache_data ((struct thread_info *)
> > @@ -1449,7 +1450,8 @@ get_child_debug_event (struct target_wai
> >        /* Record the existence of this thread.  */
> >        child_add_thread (current_event.dwProcessId,
> >  			current_event.dwThreadId,
> > -			current_event.u.CreateThread.hThread);
> > +			current_event.u.CreateThread.hThread,
> > +			current_event.u.CreateThread.lpThreadLocalBase);
> >        break;
> >
> >      case EXIT_THREAD_DEBUG_EVENT:
> > @@ -1479,7 +1481,8 @@ get_child_debug_event (struct target_wai
> >        /* Add the main thread.  */
> >        child_add_thread (current_event.dwProcessId,
> >  			main_thread_id,
> > -			current_event.u.CreateProcessInfo.hThread);
> > +			current_event.u.CreateProcessInfo.hThread,
> > +
> > current_event.u.CreateProcessInfo.lpThreadLocalBase);
> >
> >        ourstatus->value.related_pid = debug_event_ptid
> (&current_event);
> >  #ifdef _WIN32_WCE
> > @@ -1750,6 +1753,22 @@ wince_hostio_last_error (char *buf)
> >  }
> >  #endif
> >
> > +/* Write Windows OS Thread Information Block address.  */
> > +static int
> > +win32_get_tib_address (ptid_t ptid, CORE_ADDR *addr)
> > +{
> > +  win32_thread_info *th;
> > +  th = thread_rec (ptid, 0);
> > +  if (th == NULL)
> > +    return 0;
> > +  if (addr)
> > +    *addr = (CORE_ADDR) th->thread_local_base;
> > +  if (th->thread_local_base)
> > +    return 1;
> > +  return 0;
> 
> Same comments as for the same windows-nat.c changes.
  Corrected. 
> > +}
> > +
> > +
> >  static struct target_ops win32_target_ops = {
> >    win32_create_inferior,
> >    win32_attach,
> > @@ -1778,6 +1797,9 @@ static struct target_ops win32_target_op
> >  #else
> >    hostio_last_error_from_errno,
> >  #endif
> > +  NULL,
> > +  NULL,
> > +  win32_get_tib_address,
> >  };
> >
> >  /* Initialize the Win32 backend.  */
> > Index: gdbserver/win32-low.h
> > ===================================================================
> > RCS file: /cvs/src/src/gdb/gdbserver/win32-low.h,v
> > retrieving revision 1.12
> > diff -u -p -r1.12 win32-low.h
> > --- gdbserver/win32-low.h	20 Jan 2010 22:55:38 -0000	1.12
> > +++ gdbserver/win32-low.h	1 Apr 2010 12:46:54 -0000
> > @@ -28,6 +28,9 @@ typedef struct win32_thread_info
> >    /* The handle to the thread.  */
> >    HANDLE h;
> >
> > +  /* Thread Information Block address.  */
> > +  CORE_ADDR thread_local_base;
> > +
> >    /* Non zero if SuspendThread was called on this thread.  */
> >    int suspended;
> >
> 
> Otherwise, it's looking good.
Thanks for the review.

 Here is a new version of the patch,

Pierre Muller

2010-04-12  Pierre Muller  <muller@ics.u-strasbg.fr>

	* remote.c (PACKET_qGetTIBAddr): New enum element.
	(remote_get_tib_address): New function.
	(init_remote_ops): Set to_get_tib_address field
	to remote_get_tib_address.
	(_initialize_remote): Add add_packet_config_cmd
	for PACKET_qGetTIBAddr.
	* target.c (update_current_target): Set default value for
	new to_get_tib_address field.
	* target.h (target_ops): New field to_get_tib_address.
	(target_get_tib_address): New macro.
	* windows-nat.c (thread_info): Add thread_local_base field.
	(windows_add_thread): Add tlb argument of type 'void *'.
	(fake_create_process): Adapt windows_add_thread call.
	(get_windows_debug_event): Idem.
	(windows_get_tib_address): New function.
	(init_windows_ops): Set to_get_tib_address field
	to remote_get_tib_address.
	(_initialize_windows_nat): Replace info_w32_cmdlist
	initialization by a call to init_w32_command_list.
	(info_w32_command, info_w32_cmdlist): Removed from here...
	to windows-tdep.c file.
	*  windows-tdep.h (info_w32_cmdlist): Declare.
	(init_w32_command_list): New external function 
	declaration.
	* windows-tdep.c: Add several headers.
	(info_w32_cmdlist): to here, made global.
	(thread_information_32): New struct.
	(thread_information_64): New struct.
	(TIB_NAME): New char array.
	(MAX_TIB32, MAX_TIB64, FULL_TIB_SIZE): New constants.
	(maint_display_all_tib): New static variable.
	(windows_get_tlb_type): New function.
	(tlb_value_read, tlb_value_write): New functions.
	(tlb_value_funcs): New static struct.
	(tlb_make_value): New function.
	(display_one_tib): New function.
	(display_tib): New function.
	(info_w32_command): Moved from windows-nat.c.
	(init_w32_command_list): New function.
	(_initialize_windows_tdep): New function.
	New "maint set/show show-all-tib" command
	New "$_tlb" internal variable.

gdbserver/ChangeLog entry:

	* server.c (handle_query): Acknowledge support
	for 'qGetTIBAddr' if get_tib_addr field of the_target
	is set.
	Handle 'qGetTIBAddr' query.
	* target.h (target_ops): New get_tib_address field.
	* win32-low.h (win32_thread_info): Add thread_local_base field.
	* win32-low.c (child_add_thread): Add tlb argument.
	Set thread_local_base field to TLB.
	(get_child_debug_event): Adapt to child_add_thread change.
	(win32_get_tib_address): New function.
	(win32_target_ops): Set get_tib_address field to
	win32_get_tib_address
	

doc/ChangeLog entry:

	gdb.texinfo ($__tlb): Document new automatic convinience variable.
	(info w32 thread-information-block): Document new command.
	(qGetTIBAddress): Document new gdbserver query.
	(maint set/show show-all-tib): Document new command.

Index: remote.c
===================================================================
RCS file: /cvs/src/src/gdb/remote.c,v
retrieving revision 1.400
diff -u -p -r1.400 remote.c
--- remote.c	9 Apr 2010 03:00:57 -0000	1.400
+++ remote.c	12 Apr 2010 11:53:12 -0000
@@ -1139,6 +1139,7 @@ enum {
   PACKET_qXfer_spu_write,
   PACKET_qXfer_osdata,
   PACKET_qXfer_threads,
+  PACKET_qGetTIBAddr,
   PACKET_qGetTLSAddr,
   PACKET_qSupported,
   PACKET_QPassSignals,
@@ -8441,6 +8442,49 @@ remote_get_thread_local_address (struct 
   return 0;
 }
 
+/* Provide thread local base, i.e. Thread Information Block address.
+   Returns 1 if ptid is found and thread_local_base is non zero.  */
+
+int
+remote_get_tib_address (ptid_t ptid, CORE_ADDR *addr)
+{
+  if (remote_protocol_packets[PACKET_qGetTIBAddr].support != PACKET_DISABLE)
+    {
+      struct remote_state *rs = get_remote_state ();
+      char *p = rs->buf;
+      char *endp = rs->buf + get_remote_packet_size ();
+      enum packet_result result;
+
+      strcpy (p, "qGetTIBAddr:");
+      p += strlen (p);
+      p = write_ptid (p, endp, ptid);
+      *p++ = '\0';
+
+      putpkt (rs->buf);
+      getpkt (&rs->buf, &rs->buf_size, 0);
+      result = packet_ok (rs->buf,
+			  &remote_protocol_packets[PACKET_qGetTIBAddr]);
+      if (result == PACKET_OK)
+	{
+	  ULONGEST result;
+
+	  unpack_varlen_hex (rs->buf, &result);
+	  if (addr)
+	    *addr = (CORE_ADDR) result;
+	  return 1;
+	}
+      else if (result == PACKET_UNKNOWN)
+	error (_("Remote target doesn't support qGetTIBAddr packet"));
+      else
+	error (_("Remote target failed to process qGetTIBAddr request"));
+    }
+  else
+    error (_("qGetTIBAddr not supported or disabled on this target"));
+  /* Not reached.  */
+  return 0;
+}
+
+
 /* Support for inferring a target description based on the current
    architecture and the size of a 'g' packet.  While the 'g' packet
    can have any size (since optional registers can be left off the
@@ -9890,6 +9934,8 @@ Specify the serial device it is connecte
   remote_ops.to_set_circular_trace_buffer = remote_set_circular_trace_buffer;
   remote_ops.to_core_of_thread = remote_core_of_thread;
   remote_ops.to_verify_memory = remote_verify_memory;
+  remote_ops.to_get_tib_address = remote_get_tib_address;
+ 
 }
 
 /* Set up the extended remote vector by making a copy of the standard
@@ -10309,6 +10355,10 @@ Show the maximum size of the address (in
 			 "qGetTLSAddr", "get-thread-local-storage-address",
 			 0);
 
+  add_packet_config_cmd (&remote_protocol_packets[PACKET_qGetTIBAddr],
+			 "qGetTIBAddr", "get-thread-information-block-address",
+			 0);
+
   add_packet_config_cmd (&remote_protocol_packets[PACKET_bc],
 			 "bc", "reverse-continue", 0);
 
Index: target.c
===================================================================
RCS file: /cvs/src/src/gdb/target.c,v
retrieving revision 1.245
diff -u -p -r1.245 target.c
--- target.c	24 Mar 2010 01:12:13 -0000	1.245
+++ target.c	12 Apr 2010 11:53:13 -0000
@@ -660,6 +660,7 @@ update_current_target (void)
       INHERIT (to_get_raw_trace_data, t);
       INHERIT (to_set_disconnected_tracing, t);
       INHERIT (to_set_circular_trace_buffer, t);
+      INHERIT (to_get_tib_address, t);
       INHERIT (to_magic, t);
       /* Do not inherit to_memory_map.  */
       /* Do not inherit to_flash_erase.  */
@@ -853,6 +854,9 @@ update_current_target (void)
   de_fault (to_set_circular_trace_buffer,
 	    (void (*) (int))
 	    target_ignore);
+  de_fault (to_get_tib_address,
+	    (int (*) (ptid_t, CORE_ADDR *))
+	    tcomplain);
 #undef de_fault
 
   /* Finally, position the target-stack beneath the squashed
Index: target.h
===================================================================
RCS file: /cvs/src/src/gdb/target.h,v
retrieving revision 1.177
diff -u -p -r1.177 target.h
--- target.h	24 Mar 2010 01:12:13 -0000	1.177
+++ target.h	12 Apr 2010 11:53:13 -0000
@@ -682,6 +682,10 @@ struct target_ops
     int (*to_verify_memory) (struct target_ops *, const gdb_byte *data,
 			     CORE_ADDR memaddr, ULONGEST size);
 
+    /* Return the address of the start of the Thread Information Block
+       a Windows OS specific feature.  */
+    int (*to_get_tib_address) (ptid_t ptid, CORE_ADDR *addr);
+
     int to_magic;
     /* Need sub-structure for target machine related rather than comm related?
      */
@@ -1371,6 +1375,9 @@ extern int target_search_memory (CORE_AD
 #define	target_set_circular_trace_buffer(val)	\
   (*current_target.to_set_circular_trace_buffer) (val)
 
+#define target_get_tib_address(ptid, addr) \
+  (*current_target.to_get_tib_address) ((ptid), (addr))
+
 /* Command logging facility.  */
 
 #define target_log_command(p)						\
Index: windows-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/windows-nat.c,v
retrieving revision 1.207
diff -u -p -r1.207 windows-nat.c
--- windows-nat.c	10 Mar 2010 15:57:07 -0000	1.207
+++ windows-nat.c	12 Apr 2010 11:53:14 -0000
@@ -191,6 +191,7 @@ 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;
@@ -320,7 +321,7 @@ 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;
@@ -335,6 +336,7 @@ 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);
@@ -1074,15 +1076,6 @@ display_selectors (char * args, int from
     }
 }
 
-static struct cmd_list_element *info_w32_cmdlist = NULL;
-
-static void
-info_w32_command (char *args, int from_tty)
-{
-  help_list (info_w32_cmdlist, "info w32 ", class_info, gdb_stdout);
-}
-
-
 #define DEBUG_EXCEPTION_SIMPLE(x)       if (debug_exceptions) \
   printf_unfiltered ("gdb: Target exception %s at %s\n", x, \
     host_address_to_string (\
@@ -1271,9 +1264,11 @@ 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;
 }
 
@@ -1447,7 +1442,9 @@ 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:
@@ -1481,7 +1478,8 @@ 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;
 
@@ -2266,6 +2264,24 @@ windows_xfer_partial (struct target_ops 
     }
 }
 
+/* Provide thread local base, i.e. Thread Information Block address.
+   Returns 1 if ptid is found and thread_local_base is non zero.  */
+
+static int
+windows_get_tib_address (ptid_t ptid, CORE_ADDR *addr)
+{
+  thread_info *th;
+
+  th = thread_rec (ptid_get_tid (ptid), 0);
+  if (th == NULL || th->thread_local_base == 0)
+    return 0;
+
+  if (addr != NULL)
+    *addr = th->thread_local_base;
+
+  return 1;
+}
+
 static ptid_t
 windows_get_ada_task_ptid (long lwp, long thread)
 {
@@ -2314,6 +2330,7 @@ init_windows_ops (void)
   windows_ops.to_has_execution = default_child_has_execution;
   windows_ops.to_pid_to_exec_file = windows_pid_to_exec_file;
   windows_ops.to_get_ada_task_ptid = windows_get_ada_task_ptid;
+  windows_ops.to_get_tib_address = windows_get_tib_address;
 
   i386_use_watchpoints (&windows_ops);
 
@@ -2415,9 +2432,7 @@ Show whether to display kernel exception
 			   NULL, /* FIXME: i18n: */
 			   &setlist, &showlist);
 
-  add_prefix_cmd ("w32", class_info, info_w32_command,
-		  _("Print information specific to Win32 debugging."),
-		  &info_w32_cmdlist, "info w32 ", 0, &infolist);
+  init_w32_command_list ();
 
   add_cmd ("selector", class_info, display_selectors,
 	   _("Display selectors infos."),
Index: windows-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/windows-tdep.c,v
retrieving revision 1.5
diff -u -p -r1.5 windows-tdep.c
--- windows-tdep.c	1 Jan 2010 07:31:46 -0000	1.5
+++ windows-tdep.c	12 Apr 2010 11:53:14 -0000
@@ -19,6 +19,360 @@
 #include "windows-tdep.h"
 #include "gdb_obstack.h"
 #include "xml-support.h"
+#include "gdbarch.h"
+#include "target.h"
+#include "value.h"
+#include "inferior.h"
+#include "command.h"
+#include "gdbcmd.h"
+#include "gdbthread.h"
+
+struct cmd_list_element *info_w32_cmdlist;
+
+typedef struct thread_information_block_32
+  {
+    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 active_rpc_handle;			/* %fs:0x0028 */
+    uint32_t thread_local_storage;		/* %fs:0x002c */
+    uint32_t process_environment_block;		/* %fs:0x0030 */
+    uint32_t last_error_number;			/* %fs:0x0034 */
+  }
+thread_information_32;
+
+typedef struct thread_information_block_64
+  {
+    uint64_t current_seh;			/* %gs:0x0000 */
+    uint64_t current_top_of_stack; 		/* %gs:0x0008 */
+    uint64_t current_bottom_of_stack;		/* %gs:0x0010 */
+    uint64_t sub_system_tib;			/* %gs:0x0018 */
+    uint64_t fiber_data;			/* %gs:0x0020 */
+    uint64_t arbitrary_data_slot;		/* %gs:0x0028 */
+    uint64_t linear_address_tib;		/* %gs:0x0030 */
+    uint64_t environment_pointer;		/* %gs:0x0038 */
+    uint64_t process_id;			/* %gs:0x0040 */
+    uint64_t current_thread_id;			/* %gs:0x0048 */
+    uint64_t active_rpc_handle;			/* %gs:0x0050 */
+    uint64_t thread_local_storage;		/* %gs:0x0058 */
+    uint64_t process_environment_block;		/* %gs:0x0060 */
+    uint64_t last_error_number;			/* %gs:0x0068 */
+  }
+thread_information_64;
+
+
+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 */
+    " active_rpc_handle           ",	/* %fs:0x0028 */
+    " thread_local_storage        ",	/* %fs:0x002c */
+    " process_environment_block   ",	/* %fs:0x0030 */
+    " last_error_number           "	/* %fs:0x0034 */
+  };
+
+static const int MAX_TIB32 = sizeof (thread_information_32) / sizeof (uint32_t);
+static const int MAX_TIB64 = sizeof (thread_information_64) / sizeof (uint64_t);
+static const int FULL_TIB_SIZE = 0x1000;
+
+static int maint_display_all_tib = 0;
+
+/* Define Thread Local Base pointer type.  */
+
+static struct type *
+windows_get_tlb_type (struct gdbarch *gdbarch)
+{
+  struct type *dword_ptr_type, *dword32_type, *void_ptr_type;
+  struct type *peb_ldr_type, *peb_ldr_ptr_type;
+  struct type *peb_type, *peb_ptr_type, *list_type, *list_ptr_type;
+  struct type *module_list_ptr_type;
+  struct type *tib_type, *seh_type, *tib_ptr_type, *seh_ptr_type;
+
+  dword_ptr_type = arch_integer_type (gdbarch, gdbarch_ptr_bit (gdbarch),
+				 1, "DWORD_PTR");
+  dword32_type = arch_integer_type (gdbarch, 32,
+				 1, "DWORD32");
+  void_ptr_type = lookup_pointer_type (builtin_type (gdbarch)->builtin_void);
+
+  /* list entry */
+
+  list_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
+  TYPE_NAME (list_type) = xstrdup ("list");
+
+  list_ptr_type = arch_type (gdbarch, TYPE_CODE_PTR,
+			    TYPE_LENGTH (void_ptr_type), NULL);
+
+  module_list_ptr_type = void_ptr_type;
+
+  append_composite_type_field (list_type, "forward_list", module_list_ptr_type);
+  append_composite_type_field (list_type, "backward_list",
+			       module_list_ptr_type);
+
+  /* Structured Exception Handler */
+
+  seh_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
+  TYPE_NAME (seh_type) = xstrdup ("seh");
+
+  seh_ptr_type = arch_type (gdbarch, TYPE_CODE_PTR,
+			    TYPE_LENGTH (void_ptr_type), NULL);
+  TYPE_TARGET_TYPE (seh_ptr_type) = seh_type;
+
+  append_composite_type_field (seh_type, "next_seh", seh_ptr_type);
+  append_composite_type_field (seh_type, "handler", void_ptr_type);
+
+  /* struct _PEB_LDR_DATA */
+  peb_ldr_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
+  TYPE_NAME (peb_ldr_type) = xstrdup ("peb_ldr_data");
+
+  append_composite_type_field (peb_ldr_type, "length", dword32_type);
+  append_composite_type_field (peb_ldr_type, "initialized", dword32_type);
+  append_composite_type_field (peb_ldr_type, "ss_handle", void_ptr_type);
+  append_composite_type_field (peb_ldr_type, "in_load_order", list_type);
+  append_composite_type_field (peb_ldr_type, "in_memory_order", list_type);
+  append_composite_type_field (peb_ldr_type, "in_init_order", list_type);
+  append_composite_type_field (peb_ldr_type, "entry_in_progress",
+			       void_ptr_type);
+  peb_ldr_ptr_type = arch_type (gdbarch, TYPE_CODE_PTR,
+			    TYPE_LENGTH (void_ptr_type), NULL);
+  TYPE_TARGET_TYPE (peb_ldr_ptr_type) = peb_ldr_type;
+
+
+  /* struct process environment block */
+  peb_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
+  TYPE_NAME (peb_type) = xstrdup ("peb");
+
+  /* First bytes contain several flags.  */
+  append_composite_type_field (peb_type, "flags", dword_ptr_type);
+  append_composite_type_field (peb_type, "mutant", void_ptr_type);
+  append_composite_type_field (peb_type, "image_base_address", void_ptr_type);
+  append_composite_type_field (peb_type, "ldr", peb_ldr_ptr_type);
+  append_composite_type_field (peb_type, "process_parameters", void_ptr_type);
+  append_composite_type_field (peb_type, "sub_system_data", void_ptr_type);
+  append_composite_type_field (peb_type, "process_heap", void_ptr_type);
+  append_composite_type_field (peb_type, "fast_peb_lock", void_ptr_type);
+  peb_ptr_type = arch_type (gdbarch, TYPE_CODE_PTR,
+			    TYPE_LENGTH (void_ptr_type), NULL);
+  TYPE_TARGET_TYPE (peb_ptr_type) = peb_type;
+
+
+  /* struct thread information block */
+  tib_type = arch_composite_type (gdbarch, NULL, TYPE_CODE_STRUCT);
+  TYPE_NAME (tib_type) = xstrdup ("tib");
+
+  /* uint32_t current_seh;			%fs:0x0000 */
+  append_composite_type_field (tib_type, "current_seh", seh_ptr_type);
+  /* uint32_t current_top_of_stack; 		%fs:0x0004 */
+  append_composite_type_field (tib_type, "current_top_of_stack", void_ptr_type);
+  /* uint32_t current_bottom_of_stack;		%fs:0x0008 */
+  append_composite_type_field (tib_type, "current_bottom_of_stack",
+			       void_ptr_type);
+  /* uint32_t sub_system_tib;			%fs:0x000c */
+  append_composite_type_field (tib_type, "sub_system_tib", void_ptr_type);
+
+  /* uint32_t fiber_data;			%fs:0x0010 */
+  append_composite_type_field (tib_type, "fiber_data", void_ptr_type);
+  /* uint32_t arbitrary_data_slot;		%fs:0x0014 */
+  append_composite_type_field (tib_type, "arbitrary_data_slot", void_ptr_type);
+  /* uint32_t linear_address_tib;		%fs:0x0018 */
+  append_composite_type_field (tib_type, "linear_address_tib", void_ptr_type);
+  /* uint32_t environment_pointer;		%fs:0x001c */
+  append_composite_type_field (tib_type, "environment_pointer", void_ptr_type);
+  /* uint32_t process_id;			%fs:0x0020 */
+  append_composite_type_field (tib_type, "process_id", dword_ptr_type);
+  /* uint32_t current_thread_id;		%fs:0x0024 */
+  append_composite_type_field (tib_type, "thread_id", dword_ptr_type);
+  /* uint32_t active_rpc_handle;		%fs:0x0028 */
+  append_composite_type_field (tib_type, "active_rpc_handle", dword_ptr_type);
+  /* uint32_t thread_local_storage;		%fs:0x002c */
+  append_composite_type_field (tib_type, "thread_local_storage", void_ptr_type);
+  /* uint32_t process_environment_block;	%fs:0x0030 */
+  append_composite_type_field (tib_type, "process_environment_block",
+			       peb_ptr_type);
+  /* uint32_t last_error_number;		%fs:0x0034 */
+  append_composite_type_field (tib_type, "last_error_number", dword_ptr_type);
+
+  tib_ptr_type = arch_type (gdbarch, TYPE_CODE_PTR,
+			    TYPE_LENGTH (void_ptr_type), NULL);
+  TYPE_TARGET_TYPE (tib_ptr_type) = tib_type;
+
+  return tib_ptr_type;
+}
+/* The $_tlb convenience variable is a bit special.  We don't know
+   for sure the type of the value until we actually have a chance to
+   fetch the data.  The type can change depending on gdbarch, so it it
+   also dependent on which thread you have selected.
+
+     1. making $_tlb be an internalvar that creates a new value on
+     access.
+
+     2. making the value of $_tlbi be an lval_computed value.  */
+
+/* This function implements the lval_computed support for reading a
+   $_tlb value.  */
+
+static void
+tlb_value_read (struct value *val)
+{
+  CORE_ADDR tlb;
+  struct type *type = check_typedef (value_type (val));
+
+  if (!target_get_tib_address (inferior_ptid, &tlb))
+    error (_("Unable to read tlb"));
+  store_typed_address (value_contents_raw (val), type, tlb);
+}
+
+/* This function implements the lval_computed support for writing a
+   $_tlb value.  */
+
+static void
+tlb_value_write (struct value *v, struct value *fromval)
+{
+  error (_("Impossible to change tlb"));
+}
+
+static struct lval_funcs tlb_value_funcs =
+  {
+    tlb_value_read,
+    tlb_value_write
+  };
+
+
+/* Return a new value with the correct type for the tlb object of
+   the current thread using architecture GDBARCH.  Return a void value
+   if there's no object available.  */
+
+static struct value *
+tlb_make_value (struct gdbarch *gdbarch, struct internalvar *var)
+{
+  if (target_has_stack && !ptid_equal (inferior_ptid, null_ptid))
+    {
+      struct type *type = windows_get_tlb_type (gdbarch);
+      return allocate_computed_value (type, &tlb_value_funcs, NULL);
+    }
+
+  return allocate_value (builtin_type (gdbarch)->builtin_void);
+}
+
+
+/* Display thread information block of a given thread.  */
+
+static int
+display_one_tib (ptid_t ptid)
+{
+#define PTID_STRING_SIZE 40
+  char annex[PTID_STRING_SIZE];
+  char *annex_end = annex + PTID_STRING_SIZE;
+  gdb_byte *tib = NULL;
+  gdb_byte *index;
+  CORE_ADDR thread_local_base;
+  ULONGEST i, val, max, max_name, size, tib_size;
+  ULONGEST sizeof_ptr = gdbarch_ptr_bit (target_gdbarch);
+  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch);
+
+  if (sizeof_ptr == 64)
+    {
+      size = sizeof (uint64_t);
+      tib_size = sizeof (thread_information_64);
+      max = MAX_TIB64;
+    }
+  else
+    {
+      size = sizeof (uint32_t);
+      tib_size = sizeof (thread_information_32);
+      max = MAX_TIB32;
+    }
+
+  max_name = max;
+
+  if (maint_display_all_tib)
+    {
+      tib_size = FULL_TIB_SIZE;
+      max = tib_size / size;
+    }
+  
+  tib = alloca (tib_size);
+
+  /* This needs to be changed if multi-process support is added.  */
+
+  if (target_get_tib_address (ptid, &thread_local_base) == 0)
+    {
+      printf_filtered (_("Unable to get thread local base for %s\n"),
+	target_pid_to_str (ptid));
+      return -1;
+    }
+
+  if (target_read (&current_target, TARGET_OBJECT_MEMORY,
+		   annex, tib, thread_local_base, tib_size) != tib_size)
+    {
+      printf_filtered (_("Unable to read thread information block for %s at \
+address %s\n"),
+	target_pid_to_str (ptid), 
+	paddress (target_gdbarch, thread_local_base));
+      return -1;
+    }
+
+  printf_filtered (_("Thread Information Block %s at %s\n"),
+		   target_pid_to_str (ptid),
+		   paddress (target_gdbarch, thread_local_base));
+
+  index = (gdb_byte *) tib;
+
+  /* All fields have the size of a pointer, this allows to iterate 
+     using the same for loop for both layouts.  */
+  for (i = 0; i < max; i++)
+    {
+      val = extract_unsigned_integer (index, size, byte_order);
+      if (i < max_name)
+	printf_filtered (_("%s is 0x%s\n"), TIB_NAME[i], phex (val, size));
+      else if (val != 0)
+	printf_filtered (_("TIB[0x%s] is 0x%s\n"), phex (i * size, 2),
+			 phex (val, size));
+      index += size;
+    } 
+  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_tib (char * args, int from_tty)
+{
+  if (args)
+    {
+      struct thread_info *tp;
+      int gdb_id = value_as_long (parse_and_eval (args));
+
+      tp = find_thread_id (gdb_id);
+
+      if (!tp)
+	error (_("Thread ID %d not known."), gdb_id);
+
+      if (!target_thread_alive (tp->ptid))
+	error (_("Thread ID %d has terminated."), gdb_id);
+
+      display_one_tib (tp->ptid);
+    }
+  else if (!ptid_equal (inferior_ptid, null_ptid))
+    display_one_tib (inferior_ptid);
+}
 
 void
 windows_xfer_shared_library (const char* so_name, CORE_ADDR load_addr,
@@ -36,3 +390,51 @@ windows_xfer_shared_library (const char*
   obstack_grow_str (obstack, paddress (gdbarch, load_addr + 0x1000));
   obstack_grow_str (obstack, "\"/></library>");
 }
+
+static void
+info_w32_command (char *args, int from_tty)
+{
+  help_list (info_w32_cmdlist, "info w32 ", class_info, gdb_stdout);
+}
+
+static int w32_prefix_command_valid = 0;
+void
+init_w32_command_list (void)
+{
+  if (!w32_prefix_command_valid)
+    {
+      add_prefix_cmd ("w32", class_info, info_w32_command,
+		      _("Print information specific to Win32 debugging."),
+		      &info_w32_cmdlist, "info w32 ", 0, &infolist);
+      w32_prefix_command_valid = 1;
+    }
+}
+
+void
+_initialize_windows_tdep (void)
+{
+  init_w32_command_list ();
+  add_cmd ("thread-information-block", class_info, display_tib,
+	   _("Display thread information block."),
+	   &info_w32_cmdlist);
+  add_alias_cmd ("tib", "thread-information-block", class_info, 1,
+		 &info_w32_cmdlist);
+
+  add_setshow_boolean_cmd ("show-all-tib", class_maintenance,
+			   &maint_display_all_tib, _("\
+Set whether to display all non-zero fields of thread information block."), _("\
+Show whether to display all non-zero fields of thread information block."), _("\
+Use \"on\" to enable, \"off\" to disable.\n\
+If enabled, all non-zero fields of thread information block are displayed,\n\
+even if their meaning is unknown."),
+			   NULL,
+			   NULL,
+			   &maintenance_set_cmdlist,
+			   &maintenance_show_cmdlist);
+
+  /* Explicitly create without lookup, since that tries to create a
+     value with a void typed value, and when we get here, gdbarch
+     isn't initialized yet.  At this point, we're quite sure there
+     isn't another convenience variable of the same name.  */
+  create_internalvar_type_lazy ("_tlb", tlb_make_value);
+}
Index: windows-tdep.h
===================================================================
RCS file: /cvs/src/src/gdb/windows-tdep.h,v
retrieving revision 1.4
diff -u -p -r1.4 windows-tdep.h
--- windows-tdep.h	1 Jan 2010 07:31:46 -0000	1.4
+++ windows-tdep.h	12 Apr 2010 11:53:14 -0000
@@ -21,6 +21,10 @@
 struct obstack;
 struct gdbarch;
 
+extern struct cmd_list_element *info_w32_cmdlist;
+
+extern void init_w32_command_list (void);
+
 extern void windows_xfer_shared_library (const char* so_name,
 					 CORE_ADDR load_addr,
 					 struct gdbarch *gdbarch,
Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.703
diff -u -p -r1.703 gdb.texinfo
--- doc/gdb.texinfo	9 Apr 2010 20:46:40 -0000	1.703
+++ doc/gdb.texinfo	12 Apr 2010 11:53:22 -0000
@@ -8054,6 +8054,15 @@ The variable @code{$_siginfo} contains e
 (@pxref{extra signal information}).  Note that @code{$_siginfo}
 could be empty, if the application has not yet received any signals.
 For example, it will be empty before you execute the @code{run} command.
+
+@item $_tlb
+@vindex $_tlb@r{, convenience variable}
+The variable @code{$_tlb} is automatically set when debugging
+applications running on MS-Windows in native mode or connected to
+gdbserver that supports the @code{qGetTIBAddr} request. 
+@xref{General Query Packets}.
+This variable contains the address of the thread information block.
+
 @end table
 
 On HP-UX systems, if you refer to a function or variable name that
@@ -15755,6 +15764,10 @@ are:
 @tab @code{qGetTLSAddr}
 @tab Displaying @code{__thread} variables
 
+@item @code{w32 thread-information-block}
+@tab @code{qGetTIBAddr}
+@tab Display MS-Windows Thread Information Block.
+
 @item @code{search-memory}
 @tab @code{qSearch:memory}
 @tab @code{find}
@@ -16534,6 +16547,11 @@ a long value to give the information abo
 Without argument, this command displays information
 about the six segment registers.
 
+@item info w32 thread-information-block
+This command displays thread specific information stored in the
+Thread Information Block for x86 CPU family (readable using @code{$fs}
+selector for 32-bit programs and @code{$gs} for 64-bit programs).
+
 @kindex info dll
 @item info dll
 This is a Cygwin-specific alias of @code{info shared}.
@@ -29382,6 +29400,14 @@ enabled, the debug registers values are 
 removes a hardware breakpoint or watchpoint, and when the inferior
 triggers a hardware-assisted breakpoint or watchpoint.
 
+@kindex maint set show-all-tib
+@kindex maint show show-all-tib
+@item maint set show-all-tib
+@itemx maint show show-all-tib
+Control whether to show all non zero areas within a 1k block starting
+at thread local base, when using @samp{info w32 thread-information-block}
+command.
+
 @kindex maint space
 @cindex memory used by commands
 @item maint space
@@ -30595,6 +30621,28 @@ An error occurred.  @var{nn} are hex dig
 An empty reply indicates that @samp{qGetTLSAddr} is not supported by the stub.
 @end table
 
+@item qGetTIBAddr:@var{thread-id}:
+@cindex get thread information block address
+@cindex @samp{qGetTIBAddr} packet
+Fetch address of the Windows OS specific Thread Information Block.
+
+@var{thread-id} is the thread ID associated with the thread.
+
+Reply:
+@table @samp
+@item @var{XX}@dots{}
+Hex encoded (big endian) bytes representing the linear address of the
+thread information block.
+
+@item E @var{nn}
+An error occured.  This means that either the thread was not found, or the
+address could not be retrieved.
+
+@item
+An empty reply indicates that @samp{qGetTIBAddr} is not supported by the stub.
+@end table
+
+
 @item qL @var{startflag} @var{threadcount} @var{nextthread}
 Obtain thread information from RTOS.  Where: @var{startflag} (one hex
 digit) is one to indicate the first query and zero to indicate a
Index: gdbserver/server.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/server.c,v
retrieving revision 1.114
diff -u -p -r1.114 server.c
--- gdbserver/server.c	11 Apr 2010 16:33:56 -0000	1.114
+++ gdbserver/server.c	12 Apr 2010 11:53:23 -0000
@@ -1379,6 +1379,9 @@ handle_query (char *own_buf, int packet_
       if (the_target->qxfer_osdata != NULL)
 	strcat (own_buf, ";qXfer:osdata:read+");
 
+      if (the_target->get_tib_address != NULL)
+	strcat (own_buf, ";qGetTIBAddr+");
+
       if (target_supports_multi_process ())
 	strcat (own_buf, ";multiprocess+");
 
@@ -1463,6 +1466,31 @@ handle_query (char *own_buf, int packet_
       /* Otherwise, pretend we do not understand this packet.  */
     }
 
+  /* Windows OS Thread Information Block address support.  */
+  if (the_target->get_tib_address != NULL
+      && strncmp ("qGetTIBAddr:", own_buf, 12) == 0)
+    {
+      char *annex;
+      int n;
+      CORE_ADDR tlb;
+      ptid_t ptid = read_ptid (own_buf + 12, &annex);
+
+      n = (*the_target->get_tib_address) (ptid, &tlb);
+      if (n == 1)
+	{
+	  sprintf (own_buf, "%llx", tlb);
+	  return;
+	}
+      else if (n == 0)
+	{
+	  write_enn (own_buf);
+	  return;
+	}
+      return;
+    }
+
+
+
   /* Handle "monitor" commands.  */
   if (strncmp ("qRcmd,", own_buf, 6) == 0)
     {
Index: gdbserver/target.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/target.h,v
retrieving revision 1.46
diff -u -p -r1.46 target.h
--- gdbserver/target.h	11 Apr 2010 16:33:56 -0000	1.46
+++ gdbserver/target.h	12 Apr 2010 11:53:23 -0000
@@ -271,6 +271,9 @@ struct target_ops
 			unsigned const char *writebuf,
 			CORE_ADDR offset, int len);
 
+  /* Read Thread Information Block address.  */
+  int (*get_tib_address) (ptid_t ptid, CORE_ADDR *address);
+
   int (*supports_non_stop) (void);
 
   /* Enables async target events.  Returns the previous enable
Index: gdbserver/win32-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/win32-low.c,v
retrieving revision 1.44
diff -u -p -r1.44 win32-low.c
--- gdbserver/win32-low.c	11 Apr 2010 16:33:56 -0000	1.44
+++ gdbserver/win32-low.c	12 Apr 2010 11:53:23 -0000
@@ -178,7 +178,7 @@ thread_rec (ptid_t ptid, int get_context
 
 /* Add a thread to the thread list.  */
 static win32_thread_info *
-child_add_thread (DWORD pid, DWORD tid, HANDLE h)
+child_add_thread (DWORD pid, DWORD tid, HANDLE h, void *tlb)
 {
   win32_thread_info *th;
   ptid_t ptid = ptid_build (pid, tid, 0);
@@ -189,6 +189,7 @@ child_add_thread (DWORD pid, DWORD tid, 
   th = xcalloc (1, sizeof (*th));
   th->tid = tid;
   th->h = h;
+  th->thread_local_base = (CORE_ADDR) (uintptr_t) tlb;
 
   add_thread (ptid, th);
   set_inferior_regcache_data ((struct thread_info *)
@@ -1449,7 +1450,8 @@ get_child_debug_event (struct target_wai
       /* Record the existence of this thread.  */
       child_add_thread (current_event.dwProcessId,
 			current_event.dwThreadId,
-			current_event.u.CreateThread.hThread);
+			current_event.u.CreateThread.hThread,
+			current_event.u.CreateThread.lpThreadLocalBase);
       break;
 
     case EXIT_THREAD_DEBUG_EVENT:
@@ -1479,7 +1481,8 @@ get_child_debug_event (struct target_wai
       /* Add the main thread.  */
       child_add_thread (current_event.dwProcessId,
 			main_thread_id,
-			current_event.u.CreateProcessInfo.hThread);
+			current_event.u.CreateProcessInfo.hThread,
+			current_event.u.CreateProcessInfo.lpThreadLocalBase);
 
       ourstatus->value.related_pid = debug_event_ptid (&current_event);
 #ifdef _WIN32_WCE
@@ -1747,6 +1750,21 @@ wince_hostio_last_error (char *buf)
 }
 #endif
 
+/* Write Windows OS Thread Information Block address.  */
+
+static int
+win32_get_tib_address (ptid_t ptid, CORE_ADDR *addr)
+{
+  win32_thread_info *th;
+  th = thread_rec (ptid, 0);
+  if (th == NULL || th->thread_local_base == 0)
+    return 0;
+  if (addr)
+    *addr = th->thread_local_base;
+  return 1;
+}
+
+
 static struct target_ops win32_target_ops = {
   win32_create_inferior,
   win32_attach,
@@ -1776,6 +1794,9 @@ static struct target_ops win32_target_op
 #else
   hostio_last_error_from_errno,
 #endif
+  NULL,
+  NULL,
+  win32_get_tib_address,
 };
 
 /* Initialize the Win32 backend.  */
Index: gdbserver/win32-low.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/win32-low.h,v
retrieving revision 1.12
diff -u -p -r1.12 win32-low.h
--- gdbserver/win32-low.h	20 Jan 2010 22:55:38 -0000	1.12
+++ gdbserver/win32-low.h	12 Apr 2010 11:53:23 -0000
@@ -28,6 +28,9 @@ typedef struct win32_thread_info
   /* The handle to the thread.  */
   HANDLE h;
 
+  /* Thread Information Block address.  */
+  CORE_ADDR thread_local_base;
+
   /* Non zero if SuspendThread was called on this thread.  */
   int suspended;
 
Index: tui/tui-regs.c
===================================================================
RCS file: /cvs/src/src/gdb/tui/tui-regs.c,v
retrieving revision 1.36
diff -u -p -r1.36 tui-regs.c
--- tui/tui-regs.c	1 Jan 2010 07:32:07 -0000	1.36
+++ tui/tui-regs.c	12 Apr 2010 11:53:24 -0000
@@ -541,7 +541,7 @@ tui_display_register (struct tui_data_el
       int i;
 
       if (data->highlight)
-	wstandout (win_info->handle);
+	(void) wstandout (win_info->handle);
       
       wmove (win_info->handle, 0, 0);
       for (i = 1; i < win_info->width; i++)
@@ -551,7 +551,7 @@ tui_display_register (struct tui_data_el
         waddstr (win_info->handle, data->content);
 
       if (data->highlight)
-	wstandend (win_info->handle);
+	(void) wstandend (win_info->handle);
       tui_refresh_win (win_info);
     }
 }
Index: tui/tui-stack.c
===================================================================
RCS file: /cvs/src/src/gdb/tui/tui-stack.c,v
retrieving revision 1.34
diff -u -p -r1.34 tui-stack.c
--- tui/tui-stack.c	1 Jan 2010 07:32:07 -0000	1.34
+++ tui/tui-stack.c	12 Apr 2010 11:53:24 -0000
@@ -256,10 +256,10 @@ tui_show_locator_content (void)
 
       string = tui_make_status_line (&element->which_element.locator);
       wmove (locator->handle, 0, 0);
-      wstandout (locator->handle);
+      (void) wstandout (locator->handle);
       waddstr (locator->handle, string);
       wclrtoeol (locator->handle);
-      wstandend (locator->handle);
+      (void) wstandend (locator->handle);
       tui_refresh_win (locator);
       wmove (locator->handle, 0, 0);
       xfree (string);