2010-07-07 Sergio Durigan Junior <sergiodj@linux.vnet.ibm.com>gdb_7_2-branchpoint

	    Thiago Jung Bauermann  <bauerman@br.ibm.com>

	Support for hw accelerated condition watchpoints in booke powerpc.

	* breakpoint.c (fetch_watchpoint_value): Rename to fetch_subexp_value
	and move to eval.c.  Change callers.
	(insert_bp_location): Pass watchpoint condition in
	target_insert_watchpoint.
	(remove_breakpoint_1) Pass watchpoint condition in
	target_remove_watchpoint.
	(watchpoint_locations_match): Call
	target_can_accel_watchpoint_condition.
	* eval.c: Include wrapper.h.
	(fetch_subexp_value): Moved from breakpoint.c.
	* ppc-linux-nat.c (ppc_linux_region_ok_for_hw_watchpoint):
	Formatting fix.
	(can_use_watchpoint_cond_accel): New function.
	(calculate_dvc): Likewise.
	(num_memory_accesses): Likewise.
	(check_condition): Likewise.
	(ppc_linux_can_accel_watchpoint_condition): Likewise
	(ppc_linux_insert_watchpoint): Call can_use_watchpoint_cond_accel,
	check_condition and calculate_dvc.
	(ppc_linux_remove_watchpoint): Likewise.
	(_initialize_ppc_linux_nat): Set to_can_accel_watchpoint_condition to
	ppc_linux_can_accel_watchpoint_condition
	* target.c (debug_to_insert_watchpoint): Add argument for watchpoint
	condition.
	(debug_to_remove_watchpoint): Likewise.
	(debug_to_can_accel_watchpoint_condition): New function.
	(update_current_target): Set to_can_accel_watchpoint_condition.
	(setup_target_debug): Set to_can_accel_watchpoint_condition.
	* target.h: Add opaque declaration for struct expression.
	(struct target_ops) <to_insert_watchpoint>,
	<to_remove_watchpoint>: Add new arguments to pass the watchpoint
	<to_can_accel_watchpoint_condition>: New member.
	condition.  Update all callers and implementations.
	(target_can_accel_watchpoint_condition): New macro.
	* value.c (free_value_chain): New function.
	* value.h (fetch_subexp_value): New prototype.
	(free_value_chain): Likewise.

18 files changed, 503 insertions, 132 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9408b1c3316..dd81237482e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,46 @@
+2010-07-07  Sergio Durigan Junior  <sergiodj@linux.vnet.ibm.com>
+	    Thiago Jung Bauermann  <bauerman@br.ibm.com>
+
+	Support for hw accelerated condition watchpoints in booke powerpc.
+
+	* breakpoint.c (fetch_watchpoint_value): Rename to fetch_subexp_value
+	and move to eval.c.  Change callers.
+	(insert_bp_location): Pass watchpoint condition in
+	target_insert_watchpoint.
+	(remove_breakpoint_1) Pass watchpoint condition in
+	target_remove_watchpoint.
+	(watchpoint_locations_match): Call
+	target_can_accel_watchpoint_condition.
+	* eval.c: Include wrapper.h.
+	(fetch_subexp_value): Moved from breakpoint.c.
+	* ppc-linux-nat.c (ppc_linux_region_ok_for_hw_watchpoint):
+	Formatting fix.
+	(can_use_watchpoint_cond_accel): New function.
+	(calculate_dvc): Likewise.
+	(num_memory_accesses): Likewise.
+	(check_condition): Likewise.
+	(ppc_linux_can_accel_watchpoint_condition): Likewise
+	(ppc_linux_insert_watchpoint): Call can_use_watchpoint_cond_accel,
+	check_condition and calculate_dvc.
+	(ppc_linux_remove_watchpoint): Likewise.
+	(_initialize_ppc_linux_nat): Set to_can_accel_watchpoint_condition to
+	ppc_linux_can_accel_watchpoint_condition
+	* target.c (debug_to_insert_watchpoint): Add argument for watchpoint
+	condition.
+	(debug_to_remove_watchpoint): Likewise.
+	(debug_to_can_accel_watchpoint_condition): New function.
+	(update_current_target): Set to_can_accel_watchpoint_condition.
+	(setup_target_debug): Set to_can_accel_watchpoint_condition.
+	* target.h: Add opaque declaration for struct expression.
+	(struct target_ops) <to_insert_watchpoint>,
+	<to_remove_watchpoint>: Add new arguments to pass the watchpoint
+	<to_can_accel_watchpoint_condition>: New member.
+	condition.  Update all callers and implementations.
+	(target_can_accel_watchpoint_condition): New macro.
+	* value.c (free_value_chain): New function.
+	* value.h (fetch_subexp_value): New prototype.
+	(free_value_chain): Likewise.
+
 2010-07-07  Ulrich Weigand  <uweigand@de.ibm.com>
 
 	* linux-nat.c (linux_nat_do_thread_registers): Use section size
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index 3c93c4b9588..4affe0a7772 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -1234,84 +1234,6 @@ is_watchpoint (const struct breakpoint *bpt)
 	  || bpt->type == bp_watchpoint);
 }
 
-/* Find the current value of a watchpoint on EXP.  Return the value in
-   *VALP and *RESULTP and the chain of intermediate and final values
-   in *VAL_CHAIN.  RESULTP and VAL_CHAIN may be NULL if the caller does
-   not need them.
-
-   If a memory error occurs while evaluating the expression, *RESULTP will
-   be set to NULL.  *RESULTP may be a lazy value, if the result could
-   not be read from memory.  It is used to determine whether a value
-   is user-specified (we should watch the whole value) or intermediate
-   (we should watch only the bit used to locate the final value).
-
-   If the final value, or any intermediate value, could not be read
-   from memory, *VALP will be set to NULL.  *VAL_CHAIN will still be
-   set to any referenced values.  *VALP will never be a lazy value.
-   This is the value which we store in struct breakpoint.
-
-   If VAL_CHAIN is non-NULL, *VAL_CHAIN will be released from the
-   value chain.  The caller must free the values individually.  If
-   VAL_CHAIN is NULL, all generated values will be left on the value
-   chain.  */
-
-static void
-fetch_watchpoint_value (struct expression *exp, struct value **valp,
-			struct value **resultp, struct value **val_chain)
-{
-  struct value *mark, *new_mark, *result;
-  volatile struct gdb_exception ex;
-
-  *valp = NULL;
-  if (resultp)
-    *resultp = NULL;
-  if (val_chain)
-    *val_chain = NULL;
-
-  /* Evaluate the expression.  */
-  mark = value_mark ();
-  result = NULL;
-
-  TRY_CATCH (ex, RETURN_MASK_ALL)
-    {
-      result = evaluate_expression (exp);
-    }
-  if (ex.reason < 0)
-    {
-      /* Ignore memory errors, we want watchpoints pointing at
-	 inaccessible memory to still be created; otherwise, throw the
-	 error to some higher catcher.  */
-      switch (ex.error)
-	{
-	case MEMORY_ERROR:
-	  break;
-	default:
-	  throw_exception (ex);
-	  break;
-	}
-    }
-
-  new_mark = value_mark ();
-  if (mark == new_mark)
-    return;
-  if (resultp)
-    *resultp = result;
-
-  /* Make sure it's not lazy, so that after the target stops again we
-     have a non-lazy previous value to compare with.  */
-  if (result != NULL
-      && (!value_lazy (result) || gdb_value_fetch_lazy (result)))
-    *valp = result;
-
-  if (val_chain)
-    {
-      /* Return the chain of intermediate values.  We use this to
-	 decide which addresses to watch.  */
-      *val_chain = new_mark;
-      value_release_to_mark (mark);
-    }
-}
-
 /* Assuming that B is a watchpoint: returns true if the current thread
    and its running state are safe to evaluate or update watchpoint B.
    Watchpoints on local expressions need to be evaluated in the
@@ -1469,10 +1391,11 @@ update_watchpoint (struct breakpoint *b, int reparse)
     }
   else if (within_current_scope && b->exp)
     {
+      int pc = 0;
       struct value *val_chain, *v, *result, *next;
       struct program_space *frame_pspace;
 
-      fetch_watchpoint_value (b->exp, &v, &result, &val_chain);
+      fetch_subexp_value (b->exp, &pc, &v, &result, &val_chain);
 
       /* Avoid setting b->val if it's already set.  The meaning of
 	 b->val is 'the last value' user saw, and we should update
@@ -1828,7 +1751,8 @@ Note: automatically using hardware breakpoints for read-only addresses.\n"));
     {
       val = target_insert_watchpoint (bpt->address,
 				      bpt->length,
-				      bpt->watchpoint_type);
+				      bpt->watchpoint_type,
+				      bpt->owner->cond_exp);
 
       /* If trying to set a read-watchpoint, and it turns out it's not
 	 supported, try emulating one with an access watchpoint.  */
@@ -1856,7 +1780,8 @@ Note: automatically using hardware breakpoints for read-only addresses.\n"));
 	    {
 	      val = target_insert_watchpoint (bpt->address,
 					      bpt->length,
-					      hw_access);
+					      hw_access,
+					      bpt->owner->cond_exp);
 	      if (val == 0)
 		bpt->watchpoint_type = hw_access;
 	    }
@@ -2525,8 +2450,8 @@ remove_breakpoint_1 (struct bp_location *b, insertion_state_t is)
   else if (b->loc_type == bp_loc_hardware_watchpoint)
     {
       b->inserted = (is == mark_inserted);
-      val = target_remove_watchpoint (b->address, b->length, 
-				      b->watchpoint_type);
+      val = target_remove_watchpoint (b->address, b->length,
+				      b->watchpoint_type, b->owner->cond_exp);
 
       /* Failure to remove any of the hardware watchpoints comes here.  */
       if ((is == mark_uninserted) && (b->inserted))
@@ -3679,10 +3604,11 @@ watchpoint_check (void *p)
          call free_all_values.  We can't call free_all_values because
          we might be in the middle of evaluating a function call.  */
 
+      int pc = 0;
       struct value *mark = value_mark ();
       struct value *new_val;
 
-      fetch_watchpoint_value (b->exp, &new_val, NULL, NULL);
+      fetch_subexp_value (b->exp, &pc, &new_val, NULL, NULL);
 
       /* We use value_equal_contents instead of value_equal because the latter
 	 coerces an array to a pointer, thus comparing just the address of the
@@ -5262,6 +5188,21 @@ watchpoint_locations_match (struct bp_location *loc1, struct bp_location *loc2)
   gdb_assert (loc1->owner != NULL);
   gdb_assert (loc2->owner != NULL);
 
+  /* If the target can evaluate the condition expression in hardware, then we
+     we need to insert both watchpoints even if they are at the same place.
+     Otherwise the watchpoint will only trigger when the condition of whichever
+     watchpoint was inserted evaluates to true, not giving a chance for GDB to
+     check the condition of the other watchpoint.  */
+  if ((loc1->owner->cond_exp
+       && target_can_accel_watchpoint_condition (loc1->address, loc1->length,
+						 loc1->watchpoint_type,
+						 loc1->owner->cond_exp))
+      || (loc2->owner->cond_exp
+	  && target_can_accel_watchpoint_condition (loc2->address, loc2->length,
+						    loc2->watchpoint_type,
+						    loc2->owner->cond_exp)))
+    return 0;
+
   /* Note that this checks the owner's type, not the location's.  In
      case the target does not support read watchpoints, but does
      support access watchpoints, we'll have bp_read_watchpoint
@@ -8057,6 +7998,7 @@ watch_command_1 (char *arg, int accessflag, int from_tty)
   enum bptype bp_type;
   int mem_cnt = 0;
   int thread = -1;
+  int pc = 0;
 
   /* Make sure that we actually have parameters to parse.  */
   if (arg != NULL && arg[0] != '\0')
@@ -8143,7 +8085,7 @@ watch_command_1 (char *arg, int accessflag, int from_tty)
 
   exp_valid_block = innermost_block;
   mark = value_mark ();
-  fetch_watchpoint_value (exp, &val, NULL, NULL);
+  fetch_subexp_value (exp, &pc, &val, NULL, NULL);
   if (val != NULL)
     release_value (val);
 
diff --git a/gdb/eval.c b/gdb/eval.c
index 9a60616d56c..ff17c340181 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -43,6 +43,7 @@
 #include "gdb_obstack.h"
 #include "objfiles.h"
 #include "python/python.h"
+#include "wrapper.h"
 
 #include "gdb_assert.h"
 
@@ -186,6 +187,84 @@ evaluate_subexpression_type (struct expression *exp, int subexp)
   return evaluate_subexp (NULL_TYPE, exp, &subexp, EVAL_AVOID_SIDE_EFFECTS);
 }
 
+/* Find the current value of a watchpoint on EXP.  Return the value in
+   *VALP and *RESULTP and the chain of intermediate and final values
+   in *VAL_CHAIN.  RESULTP and VAL_CHAIN may be NULL if the caller does
+   not need them.
+
+   If a memory error occurs while evaluating the expression, *RESULTP will
+   be set to NULL.  *RESULTP may be a lazy value, if the result could
+   not be read from memory.  It is used to determine whether a value
+   is user-specified (we should watch the whole value) or intermediate
+   (we should watch only the bit used to locate the final value).
+
+   If the final value, or any intermediate value, could not be read
+   from memory, *VALP will be set to NULL.  *VAL_CHAIN will still be
+   set to any referenced values.  *VALP will never be a lazy value.
+   This is the value which we store in struct breakpoint.
+
+   If VAL_CHAIN is non-NULL, *VAL_CHAIN will be released from the
+   value chain.  The caller must free the values individually.  If
+   VAL_CHAIN is NULL, all generated values will be left on the value
+   chain.  */
+
+void
+fetch_subexp_value (struct expression *exp, int *pc, struct value **valp,
+		    struct value **resultp, struct value **val_chain)
+{
+  struct value *mark, *new_mark, *result;
+  volatile struct gdb_exception ex;
+
+  *valp = NULL;
+  if (resultp)
+    *resultp = NULL;
+  if (val_chain)
+    *val_chain = NULL;
+
+  /* Evaluate the expression.  */
+  mark = value_mark ();
+  result = NULL;
+
+  TRY_CATCH (ex, RETURN_MASK_ALL)
+    {
+      result = evaluate_subexp (NULL_TYPE, exp, pc, EVAL_NORMAL);
+    }
+  if (ex.reason < 0)
+    {
+      /* Ignore memory errors, we want watchpoints pointing at
+	 inaccessible memory to still be created; otherwise, throw the
+	 error to some higher catcher.  */
+      switch (ex.error)
+	{
+	case MEMORY_ERROR:
+	  break;
+	default:
+	  throw_exception (ex);
+	  break;
+	}
+    }
+
+  new_mark = value_mark ();
+  if (mark == new_mark)
+    return;
+  if (resultp)
+    *resultp = result;
+
+  /* Make sure it's not lazy, so that after the target stops again we
+     have a non-lazy previous value to compare with.  */
+  if (result != NULL
+      && (!value_lazy (result) || gdb_value_fetch_lazy (result)))
+    *valp = result;
+
+  if (val_chain)
+    {
+      /* Return the chain of intermediate values.  We use this to
+	 decide which addresses to watch.  */
+      *val_chain = new_mark;
+      value_release_to_mark (mark);
+    }
+}
+
 /* Extract a field operation from an expression.  If the subexpression
    of EXP starting at *SUBEXP is not a structure dereference
    operation, return NULL.  Otherwise, return the name of the
diff --git a/gdb/i386-nat.c b/gdb/i386-nat.c
index 82c51d70c20..eaa36442385 100644
--- a/gdb/i386-nat.c
+++ b/gdb/i386-nat.c
@@ -484,7 +484,8 @@ Invalid value %d of operation in i386_handle_nonaligned_watchpoint.\n"),
    of the type TYPE.  Return 0 on success, -1 on failure.  */
 
 static int
-i386_insert_watchpoint (CORE_ADDR addr, int len, int type)
+i386_insert_watchpoint (CORE_ADDR addr, int len, int type,
+			struct expression *cond)
 {
   int retval;
 
@@ -511,7 +512,8 @@ i386_insert_watchpoint (CORE_ADDR addr, int len, int type)
    address ADDR, whose length is LEN bytes, and for accesses of the
    type TYPE.  Return 0 on success, -1 on failure.  */
 static int
-i386_remove_watchpoint (CORE_ADDR addr, int len, int type)
+i386_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			struct expression *cond)
 {
   int retval;
 
diff --git a/gdb/ia64-linux-nat.c b/gdb/ia64-linux-nat.c
index e6a70778eb9..d33e88e1546 100644
--- a/gdb/ia64-linux-nat.c
+++ b/gdb/ia64-linux-nat.c
@@ -530,7 +530,8 @@ is_power_of_2 (int val)
 }
 
 static int
-ia64_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw)
+ia64_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw,
+			      struct expression *cond)
 {
   struct lwp_info *lp;
   ptid_t ptid;
@@ -584,7 +585,8 @@ ia64_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw)
 }
 
 static int
-ia64_linux_remove_watchpoint (CORE_ADDR addr, int len, int type)
+ia64_linux_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			      struct expression *cond)
 {
   int idx;
   long dbr_addr, dbr_mask;
diff --git a/gdb/inf-ttrace.c b/gdb/inf-ttrace.c
index 199ceb9f175..aa0462ff235 100644
--- a/gdb/inf-ttrace.c
+++ b/gdb/inf-ttrace.c
@@ -314,7 +314,8 @@ inf_ttrace_disable_page_protections (pid_t pid)
    type TYPE.  */
 
 static int
-inf_ttrace_insert_watchpoint (CORE_ADDR addr, int len, int type)
+inf_ttrace_insert_watchpoint (CORE_ADDR addr, int len, int type,
+			      struct expression *cond)
 {
   const int pagesize = inf_ttrace_page_dict.pagesize;
   pid_t pid = ptid_get_pid (inferior_ptid);
@@ -337,7 +338,8 @@ inf_ttrace_insert_watchpoint (CORE_ADDR addr, int len, int type)
    type TYPE.  */
 
 static int
-inf_ttrace_remove_watchpoint (CORE_ADDR addr, int len, int type)
+inf_ttrace_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			      struct expression *cond)
 {
   const int pagesize = inf_ttrace_page_dict.pagesize;
   pid_t pid = ptid_get_pid (inferior_ptid);
diff --git a/gdb/mips-linux-nat.c b/gdb/mips-linux-nat.c
index fe0519262ef..e9e7c027792 100644
--- a/gdb/mips-linux-nat.c
+++ b/gdb/mips-linux-nat.c
@@ -926,7 +926,8 @@ populate_regs_from_watches (struct pt_watch_regs *regs)
    watch.  Return zero on success.  */
 
 static int
-mips_linux_insert_watchpoint (CORE_ADDR addr, int len, int type)
+mips_linux_insert_watchpoint (CORE_ADDR addr, int len, int type,
+			      struct expression *cond)
 {
   struct pt_watch_regs regs;
   struct mips_watchpoint *new_watch;
@@ -975,7 +976,8 @@ mips_linux_insert_watchpoint (CORE_ADDR addr, int len, int type)
    Return zero on success.  */
 
 static int
-mips_linux_remove_watchpoint (CORE_ADDR addr, int len, int type)
+mips_linux_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			      struct expression *cond)
 {
   int retval;
   int deleted_one;
diff --git a/gdb/nto-procfs.c b/gdb/nto-procfs.c
index 2741ecfac12..a8cd1cd5c21 100644
--- a/gdb/nto-procfs.c
+++ b/gdb/nto-procfs.c
@@ -1506,13 +1506,15 @@ procfs_can_use_hw_breakpoint (int type, int cnt, int othertype)
 }
 
 static int
-procfs_remove_hw_watchpoint (CORE_ADDR addr, int len, int type)
+procfs_remove_hw_watchpoint (CORE_ADDR addr, int len, int type,
+			     struct expression *cond)
 {
   return procfs_hw_watchpoint (addr, -1, type);
 }
 
 static int
-procfs_insert_hw_watchpoint (CORE_ADDR addr, int len, int type)
+procfs_insert_hw_watchpoint (CORE_ADDR addr, int len, int type,
+			     struct expression *cond)
 {
   return procfs_hw_watchpoint (addr, len, type);
 }
diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index f61ac5d6fa7..e8d96f617f0 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -1492,7 +1492,7 @@ ppc_linux_region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
       if (booke_debug_info.data_bp_alignment
 	  && (addr + len > (addr & ~(booke_debug_info.data_bp_alignment - 1))
 	      + booke_debug_info.data_bp_alignment))
-	  return 0;
+	return 0;
     }
   /* addr+len must fall in the 8 byte watchable region for DABR-based
      processors (i.e., server processors).  Without the new BookE ptrace
@@ -1685,8 +1685,202 @@ get_trigger_type (int rw)
   return t;
 }
 
+/* Check whether we have at least one free DVC register.  */
+static int
+can_use_watchpoint_cond_accel (void)
+{
+  struct thread_points *p;
+  int tid = TIDGET (inferior_ptid);
+  int cnt = booke_debug_info.num_condition_regs, i;
+  CORE_ADDR tmp_value;
+
+  if (!have_ptrace_booke_interface () || cnt == 0)
+    return 0;
+
+  p = booke_find_thread_points_by_tid (tid, 0);
+
+  if (p)
+    {
+      for (i = 0; i < max_slots_number; i++)
+	if (p->hw_breaks[i].hw_break != NULL
+	    && (p->hw_breaks[i].hw_break->condition_mode
+		!= PPC_BREAKPOINT_CONDITION_NONE))
+	  cnt--;
+
+      /* There are no available slots now.  */
+      if (cnt <= 0)
+	return 0;
+    }
+
+  return 1;
+}
+
+/* Calculate the enable bits and the contents of the Data Value Compare
+   debug register present in BookE processors.
+
+   ADDR is the address to be watched, LEN is the length of watched data
+   and DATA_VALUE is the value which will trigger the watchpoint.
+   On exit, CONDITION_MODE will hold the enable bits for the DVC, and
+   CONDITION_VALUE will hold the value which should be put in the
+   DVC register.  */
+static void
+calculate_dvc (CORE_ADDR addr, int len, CORE_ADDR data_value,
+	       uint32_t *condition_mode, uint64_t *condition_value)
+{
+  int i, num_byte_enable, align_offset, num_bytes_off_dvc,
+      rightmost_enabled_byte;
+  CORE_ADDR addr_end_data, addr_end_dvc;
+
+  /* The DVC register compares bytes within fixed-length windows which
+     are word-aligned, with length equal to that of the DVC register.
+     We need to calculate where our watch region is relative to that
+     window and enable comparison of the bytes which fall within it.  */
+
+  align_offset = addr % booke_debug_info.sizeof_condition;
+  addr_end_data = addr + len;
+  addr_end_dvc = (addr - align_offset
+		  + booke_debug_info.sizeof_condition);
+  num_bytes_off_dvc = (addr_end_data > addr_end_dvc)?
+			 addr_end_data - addr_end_dvc : 0;
+  num_byte_enable = len - num_bytes_off_dvc;
+  /* Here, bytes are numbered from right to left.  */
+  rightmost_enabled_byte = (addr_end_data < addr_end_dvc)?
+			      addr_end_dvc - addr_end_data : 0;
+
+  *condition_mode = PPC_BREAKPOINT_CONDITION_AND;
+  for (i = 0; i < num_byte_enable; i++)
+    *condition_mode |= PPC_BREAKPOINT_CONDITION_BE (i + rightmost_enabled_byte);
+
+  /* Now we need to match the position within the DVC of the comparison
+     value with where the watch region is relative to the window
+     (i.e., the ALIGN_OFFSET).  */
+
+  *condition_value = ((uint64_t) data_value >> num_bytes_off_dvc * 8
+		      << rightmost_enabled_byte * 8);
+}
+
+/* Return the number of memory locations that need to be accessed to
+   evaluate the expression which generated the given value chain.
+   Returns -1 if there's any register access involved, or if there are
+   other kinds of values which are not acceptable in a condition
+   expression (e.g., lval_computed or lval_internalvar).  */
+static int
+num_memory_accesses (struct value *v)
+{
+  int found_memory_cnt = 0;
+  struct value *head = v;
+
+  /* The idea here is that evaluating an expression generates a series
+     of values, one holding the value of every subexpression.  (The
+     expression a*b+c has five subexpressions: a, b, a*b, c, and
+     a*b+c.)  GDB's values hold almost enough information to establish
+     the criteria given above --- they identify memory lvalues,
+     register lvalues, computed values, etcetera.  So we can evaluate
+     the expression, and then scan the chain of values that leaves
+     behind to determine the memory locations involved in the evaluation
+     of an expression.
+
+     However, I don't think that the values returned by inferior
+     function calls are special in any way.  So this function may not
+     notice that an expression contains an inferior function call.
+     FIXME.  */
+
+  for (; v; v = value_next (v))
+    {
+      /* Constants and values from the history are fine.  */
+      if (VALUE_LVAL (v) == not_lval || deprecated_value_modifiable (v) == 0)
+	continue;
+      else if (VALUE_LVAL (v) == lval_memory)
+	{
+	  /* A lazy memory lvalue is one that GDB never needed to fetch;
+	     we either just used its address (e.g., `a' in `a.b') or
+	     we never needed it at all (e.g., `a' in `a,b').  */
+	  if (!value_lazy (v))
+	    found_memory_cnt++;
+	}
+      /* Other kinds of values are not fine. */
+      else
+	return -1;
+    }
+
+  return found_memory_cnt;
+}
+
+/* Verifies whether the expression COND can be implemented using the
+   DVC (Data Value Compare) register in BookE processors.  The expression
+   must test the watch value for equality with a constant expression.
+   If the function returns 1, DATA_VALUE will contain the constant against
+   which the watch value should be compared.  */
+static int
+check_condition (CORE_ADDR watch_addr, struct expression *cond,
+		 CORE_ADDR *data_value)
+{
+  int pc = 1, num_accesses_left, num_accesses_right;
+  struct value *left_val, *right_val, *left_chain, *right_chain;
+
+  if (cond->elts[0].opcode != BINOP_EQUAL)
+    return 0;
+
+  fetch_subexp_value (cond, &pc, &left_val, NULL, &left_chain);
+  num_accesses_left = num_memory_accesses (left_chain);
+
+  if (left_val == NULL || num_accesses_left < 0)
+    {
+      free_value_chain (left_chain);
+
+      return 0;
+    }
+
+  fetch_subexp_value (cond, &pc, &right_val, NULL, &right_chain);
+  num_accesses_right = num_memory_accesses (right_chain);
+
+  if (right_val == NULL || num_accesses_right < 0)
+    {
+      free_value_chain (left_chain);
+      free_value_chain (right_chain);
+
+      return 0;
+    }
+
+  if (num_accesses_left == 1 && num_accesses_right == 0
+      && VALUE_LVAL (left_val) == lval_memory
+      && value_address (left_val) == watch_addr)
+    *data_value = value_as_long (right_val);
+  else if (num_accesses_left == 0 && num_accesses_right == 1
+	   && VALUE_LVAL (right_val) == lval_memory
+	   && value_address (right_val) == watch_addr)
+    *data_value = value_as_long (left_val);
+  else
+    {
+      free_value_chain (left_chain);
+      free_value_chain (right_chain);
+
+      return 0;
+    }
+
+  free_value_chain (left_chain);
+  free_value_chain (right_chain);
+
+  return 1;
+}
+
+/* Return non-zero if the target is capable of using hardware to evaluate
+   the condition expression, thus only triggering the watchpoint when it is
+   true.  */
+static int
+ppc_linux_can_accel_watchpoint_condition (CORE_ADDR addr, int len, int rw,
+					  struct expression *cond)
+{
+  CORE_ADDR data_value;
+
+  return (have_ptrace_booke_interface ()
+	  && booke_debug_info.num_condition_regs > 0
+	  && check_condition (addr, cond, &data_value));
+}
+
 static int
-ppc_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw)
+ppc_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw,
+			     struct expression *cond)
 {
   struct lwp_info *lp;
   ptid_t ptid;
@@ -1695,14 +1889,23 @@ ppc_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw)
   if (have_ptrace_booke_interface ())
     {
       struct ppc_hw_breakpoint p;
+      CORE_ADDR data_value;
+
+      if (cond && can_use_watchpoint_cond_accel ()
+	  && check_condition (addr, cond, &data_value))
+	calculate_dvc (addr, len, data_value, &p.condition_mode,
+		       &p.condition_value);
+      else
+	{
+	  p.condition_mode  = PPC_BREAKPOINT_CONDITION_NONE;
+	  p.condition_value = 0;
+	}
 
       p.version         = PPC_DEBUG_CURRENT_VERSION;
       p.trigger_type    = get_trigger_type (rw);
       p.addr_mode       = PPC_BREAKPOINT_MODE_EXACT;
-      p.condition_mode  = PPC_BREAKPOINT_CONDITION_NONE;
       p.addr            = (uint64_t) addr;
       p.addr2           = 0;
-      p.condition_value = 0;
 
       ALL_LWPS (lp, ptid)
 	booke_insert_point (&p, TIDGET (ptid));
@@ -1749,7 +1952,8 @@ ppc_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw)
       saved_dabr_value = dabr_value;
 
       ALL_LWPS (lp, ptid)
-	if (ptrace (PTRACE_SET_DEBUGREG, TIDGET (ptid), 0, saved_dabr_value) < 0)
+	if (ptrace (PTRACE_SET_DEBUGREG, TIDGET (ptid), 0,
+		    saved_dabr_value) < 0)
 	  return -1;
 
       ret = 0;
@@ -1759,7 +1963,8 @@ ppc_linux_insert_watchpoint (CORE_ADDR addr, int len, int rw)
 }
 
 static int
-ppc_linux_remove_watchpoint (CORE_ADDR addr, int len, int rw)
+ppc_linux_remove_watchpoint (CORE_ADDR addr, int len, int rw,
+			     struct expression *cond)
 {
   struct lwp_info *lp;
   ptid_t ptid;
@@ -1768,14 +1973,23 @@ ppc_linux_remove_watchpoint (CORE_ADDR addr, int len, int rw)
   if (have_ptrace_booke_interface ())
     {
       struct ppc_hw_breakpoint p;
+      CORE_ADDR data_value;
+
+      if (cond && booke_debug_info.num_condition_regs > 0
+	  && check_condition (addr, cond, &data_value))
+	calculate_dvc (addr, len, data_value, &p.condition_mode,
+		       &p.condition_value);
+      else
+	{
+	  p.condition_mode  = PPC_BREAKPOINT_CONDITION_NONE;
+	  p.condition_value = 0;
+	}
 
       p.version         = PPC_DEBUG_CURRENT_VERSION;
       p.trigger_type    = get_trigger_type (rw);
       p.addr_mode       = PPC_BREAKPOINT_MODE_EXACT;
-      p.condition_mode  = PPC_BREAKPOINT_CONDITION_NONE;
       p.addr            = (uint64_t) addr;
       p.addr2           = 0;
-      p.condition_value = 0;
 
       ALL_LWPS (lp, ptid)
 	booke_remove_point (&p, TIDGET (ptid));
@@ -1786,7 +2000,8 @@ ppc_linux_remove_watchpoint (CORE_ADDR addr, int len, int rw)
     {
       saved_dabr_value = 0;
       ALL_LWPS (lp, ptid)
-	if (ptrace (PTRACE_SET_DEBUGREG, TIDGET (ptid), 0, saved_dabr_value) < 0)
+	if (ptrace (PTRACE_SET_DEBUGREG, TIDGET (ptid), 0,
+		    saved_dabr_value) < 0)
 	  return -1;
 
       ret = 0;
@@ -2137,6 +2352,7 @@ _initialize_ppc_linux_nat (void)
   t->to_stopped_by_watchpoint = ppc_linux_stopped_by_watchpoint;
   t->to_stopped_data_address = ppc_linux_stopped_data_address;
   t->to_watchpoint_addr_within_range = ppc_linux_watchpoint_addr_within_range;
+  t->to_can_accel_watchpoint_condition = ppc_linux_can_accel_watchpoint_condition;
 
   t->to_read_description = ppc_linux_read_description;
   t->to_auxv_parse = ppc_linux_auxv_parse;
diff --git a/gdb/procfs.c b/gdb/procfs.c
index 97a87e39b99..de8e26dd597 100644
--- a/gdb/procfs.c
+++ b/gdb/procfs.c
@@ -5161,7 +5161,8 @@ procfs_stopped_data_address (struct target_ops *targ, CORE_ADDR *addr)
 }
 
 static int
-procfs_insert_watchpoint (CORE_ADDR addr, int len, int type)
+procfs_insert_watchpoint (CORE_ADDR addr, int len, int type,
+			  struct expression *cond)
 {
   if (!target_have_steppable_watchpoint
       && !gdbarch_have_nonsteppable_watchpoint (target_gdbarch))
@@ -5182,7 +5183,8 @@ procfs_insert_watchpoint (CORE_ADDR addr, int len, int type)
 }
 
 static int
-procfs_remove_watchpoint (CORE_ADDR addr, int len, int type)
+procfs_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			  struct expression *cond)
 {
   return procfs_set_watchpoint (inferior_ptid, addr, 0, 0, 0);
 }
diff --git a/gdb/remote-m32r-sdi.c b/gdb/remote-m32r-sdi.c
index ad2177434cd..ca450d5ec35 100644
--- a/gdb/remote-m32r-sdi.c
+++ b/gdb/remote-m32r-sdi.c
@@ -1421,7 +1421,8 @@ m32r_can_use_hw_watchpoint (int type, int cnt, int othertype)
    watchpoint. */
 
 static int
-m32r_insert_watchpoint (CORE_ADDR addr, int len, int type)
+m32r_insert_watchpoint (CORE_ADDR addr, int len, int type,
+			struct expression *cond)
 {
   int i;
 
@@ -1445,7 +1446,8 @@ m32r_insert_watchpoint (CORE_ADDR addr, int len, int type)
 }
 
 static int
-m32r_remove_watchpoint (CORE_ADDR addr, int len, int type)
+m32r_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			struct expression *cond)
 {
   int i;
 
diff --git a/gdb/remote-mips.c b/gdb/remote-mips.c
index 28d2ecb01a4..ec2e5eb38b1 100644
--- a/gdb/remote-mips.c
+++ b/gdb/remote-mips.c
@@ -2401,7 +2401,8 @@ calculate_mask (CORE_ADDR addr, int len)
    watchpoint. */
 
 int
-mips_insert_watchpoint (CORE_ADDR addr, int len, int type)
+mips_insert_watchpoint (CORE_ADDR addr, int len, int type,
+			struct expression *cond)
 {
   if (mips_set_breakpoint (addr, len, type))
     return -1;
@@ -2412,7 +2413,8 @@ mips_insert_watchpoint (CORE_ADDR addr, int len, int type)
 /* Remove a watchpoint.  */
 
 int
-mips_remove_watchpoint (CORE_ADDR addr, int len, int type)
+mips_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			struct expression *cond)
 {
   if (mips_clear_breakpoint (addr, len, type))
     return -1;
diff --git a/gdb/remote.c b/gdb/remote.c
index 385d62a9528..71eee5d892a 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -7646,7 +7646,8 @@ watchpoint_to_Z_packet (int type)
 }
 
 static int
-remote_insert_watchpoint (CORE_ADDR addr, int len, int type)
+remote_insert_watchpoint (CORE_ADDR addr, int len, int type,
+			  struct expression *cond)
 {
   struct remote_state *rs = get_remote_state ();
   char *p;
@@ -7679,7 +7680,8 @@ remote_insert_watchpoint (CORE_ADDR addr, int len, int type)
 
 
 static int
-remote_remove_watchpoint (CORE_ADDR addr, int len, int type)
+remote_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			  struct expression *cond)
 {
   struct remote_state *rs = get_remote_state ();
   char *p;
diff --git a/gdb/s390-nat.c b/gdb/s390-nat.c
index 3af42ff80df..b412fda507b 100644
--- a/gdb/s390-nat.c
+++ b/gdb/s390-nat.c
@@ -335,7 +335,8 @@ s390_fix_watch_points (ptid_t ptid)
 }
 
 static int
-s390_insert_watchpoint (CORE_ADDR addr, int len, int type)
+s390_insert_watchpoint (CORE_ADDR addr, int len, int type,
+			struct expression *cond)
 {
   struct lwp_info *lp;
   ptid_t ptid;
@@ -356,7 +357,8 @@ s390_insert_watchpoint (CORE_ADDR addr, int len, int type)
 }
 
 static int
-s390_remove_watchpoint (CORE_ADDR addr, int len, int type)
+s390_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			struct expression *cond)
 {
   struct lwp_info *lp;
   ptid_t ptid;
diff --git a/gdb/target.c b/gdb/target.c
index 7c9793db607..862df4ec71b 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -117,9 +117,11 @@ static int debug_to_insert_hw_breakpoint (struct gdbarch *,
 static int debug_to_remove_hw_breakpoint (struct gdbarch *,
 					  struct bp_target_info *);
 
-static int debug_to_insert_watchpoint (CORE_ADDR, int, int);
+static int debug_to_insert_watchpoint (CORE_ADDR, int, int,
+				       struct expression *);
 
-static int debug_to_remove_watchpoint (CORE_ADDR, int, int);
+static int debug_to_remove_watchpoint (CORE_ADDR, int, int,
+				       struct expression *);
 
 static int debug_to_stopped_by_watchpoint (void);
 
@@ -130,6 +132,9 @@ static int debug_to_watchpoint_addr_within_range (struct target_ops *,
 
 static int debug_to_region_ok_for_hw_watchpoint (CORE_ADDR, int);
 
+static int debug_to_can_accel_watchpoint_condition (CORE_ADDR, int, int,
+						    struct expression *);
+
 static void debug_to_terminal_init (void);
 
 static void debug_to_terminal_inferior (void);
@@ -607,6 +612,7 @@ update_current_target (void)
       INHERIT (to_stopped_by_watchpoint, t);
       INHERIT (to_watchpoint_addr_within_range, t);
       INHERIT (to_region_ok_for_hw_watchpoint, t);
+      INHERIT (to_can_accel_watchpoint_condition, t);
       INHERIT (to_terminal_init, t);
       INHERIT (to_terminal_inferior, t);
       INHERIT (to_terminal_ours_for_output, t);
@@ -728,10 +734,10 @@ update_current_target (void)
 	    (int (*) (struct gdbarch *, struct bp_target_info *))
 	    return_minus_one);
   de_fault (to_insert_watchpoint,
-	    (int (*) (CORE_ADDR, int, int))
+	    (int (*) (CORE_ADDR, int, int, struct expression *))
 	    return_minus_one);
   de_fault (to_remove_watchpoint,
-	    (int (*) (CORE_ADDR, int, int))
+	    (int (*) (CORE_ADDR, int, int, struct expression *))
 	    return_minus_one);
   de_fault (to_stopped_by_watchpoint,
 	    (int (*) (void))
@@ -743,6 +749,9 @@ update_current_target (void)
 	    default_watchpoint_addr_within_range);
   de_fault (to_region_ok_for_hw_watchpoint,
 	    default_region_ok_for_hw_watchpoint);
+  de_fault (to_can_accel_watchpoint_condition,
+            (int (*) (CORE_ADDR, int, int, struct expression *))
+            return_zero);
   de_fault (to_terminal_init,
 	    (void (*) (void))
 	    target_ignore);
@@ -3314,6 +3323,21 @@ debug_to_region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
 }
 
 static int
+debug_to_can_accel_watchpoint_condition (CORE_ADDR addr, int len, int rw,
+					 struct expression *cond)
+{
+  int retval;
+
+  retval = debug_target.to_can_accel_watchpoint_condition (addr, len, rw, cond);
+
+  fprintf_unfiltered (gdb_stdlog,
+		      "target_can_accel_watchpoint_condition (0x%lx, %d, %d, 0x%lx) = %ld\n",
+		      (unsigned long) addr, len, rw, (unsigned long) cond,
+		      (unsigned long) retval);
+  return retval;
+}
+
+static int
 debug_to_stopped_by_watchpoint (void)
 {
   int retval;
@@ -3388,28 +3412,32 @@ debug_to_remove_hw_breakpoint (struct gdbarch *gdbarch,
 }
 
 static int
-debug_to_insert_watchpoint (CORE_ADDR addr, int len, int type)
+debug_to_insert_watchpoint (CORE_ADDR addr, int len, int type,
+			    struct expression *cond)
 {
   int retval;
 
-  retval = debug_target.to_insert_watchpoint (addr, len, type);
+  retval = debug_target.to_insert_watchpoint (addr, len, type, cond);
 
   fprintf_unfiltered (gdb_stdlog,
-		      "target_insert_watchpoint (0x%lx, %d, %d) = %ld\n",
-		      (unsigned long) addr, len, type, (unsigned long) retval);
+		      "target_insert_watchpoint (0x%lx, %d, %d, 0x%ld) = %ld\n",
+		      (unsigned long) addr, len, type, (unsigned long) cond,
+		      (unsigned long) retval);
   return retval;
 }
 
 static int
-debug_to_remove_watchpoint (CORE_ADDR addr, int len, int type)
+debug_to_remove_watchpoint (CORE_ADDR addr, int len, int type,
+			    struct expression *cond)
 {
   int retval;
 
-  retval = debug_target.to_remove_watchpoint (addr, len, type);
+  retval = debug_target.to_remove_watchpoint (addr, len, type, cond);
 
   fprintf_unfiltered (gdb_stdlog,
-		      "target_remove_watchpoint (0x%lx, %d, %d) = %ld\n",
-		      (unsigned long) addr, len, type, (unsigned long) retval);
+		      "target_remove_watchpoint (0x%lx, %d, %d, 0x%ld) = %ld\n",
+		      (unsigned long) addr, len, type, (unsigned long) cond,
+		      (unsigned long) retval);
   return retval;
 }
 
@@ -3664,6 +3692,7 @@ setup_target_debug (void)
   current_target.to_stopped_data_address = debug_to_stopped_data_address;
   current_target.to_watchpoint_addr_within_range = debug_to_watchpoint_addr_within_range;
   current_target.to_region_ok_for_hw_watchpoint = debug_to_region_ok_for_hw_watchpoint;
+  current_target.to_can_accel_watchpoint_condition = debug_to_can_accel_watchpoint_condition;
   current_target.to_terminal_init = debug_to_terminal_init;
   current_target.to_terminal_inferior = debug_to_terminal_inferior;
   current_target.to_terminal_ours_for_output = debug_to_terminal_ours_for_output;
diff --git a/gdb/target.h b/gdb/target.h
index 3c8a6161225..3c8c017489c 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -37,6 +37,8 @@ struct uploaded_tsv;
 struct uploaded_tp;
 struct static_tracepoint_marker;
 
+struct expression;
+
 /* This include file defines the interface between the main part
    of the debugger, and the part which is target-specific, or
    specific to the communications interface between us and the
@@ -426,8 +428,12 @@ struct target_ops
     int (*to_can_use_hw_breakpoint) (int, int, int);
     int (*to_insert_hw_breakpoint) (struct gdbarch *, struct bp_target_info *);
     int (*to_remove_hw_breakpoint) (struct gdbarch *, struct bp_target_info *);
-    int (*to_remove_watchpoint) (CORE_ADDR, int, int);
-    int (*to_insert_watchpoint) (CORE_ADDR, int, int);
+
+    /* Documentation of what the two routines below are expected to do is
+       provided with the corresponding target_* macros.  */
+    int (*to_remove_watchpoint) (CORE_ADDR, int, int, struct expression *);
+    int (*to_insert_watchpoint) (CORE_ADDR, int, int, struct expression *);
+
     int (*to_stopped_by_watchpoint) (void);
     int to_have_steppable_watchpoint;
     int to_have_continuable_watchpoint;
@@ -435,6 +441,8 @@ struct target_ops
     int (*to_watchpoint_addr_within_range) (struct target_ops *,
 					    CORE_ADDR, CORE_ADDR, int);
     int (*to_region_ok_for_hw_watchpoint) (CORE_ADDR, int);
+    int (*to_can_accel_watchpoint_condition) (CORE_ADDR, int, int,
+					      struct expression *);
     void (*to_terminal_init) (void);
     void (*to_terminal_inferior) (void);
     void (*to_terminal_ours_for_output) (void);
@@ -1298,14 +1306,15 @@ extern char *normal_pid_to_str (ptid_t ptid);
 
 /* Set/clear a hardware watchpoint starting at ADDR, for LEN bytes.
    TYPE is 0 for write, 1 for read, and 2 for read/write accesses.
+   COND is the expression for its condition, or NULL if there's none.
    Returns 0 for success, 1 if the watchpoint type is not supported,
    -1 for failure.  */
 
-#define	target_insert_watchpoint(addr, len, type)	\
-     (*current_target.to_insert_watchpoint) (addr, len, type)
+#define	target_insert_watchpoint(addr, len, type, cond) \
+     (*current_target.to_insert_watchpoint) (addr, len, type, cond)
 
-#define	target_remove_watchpoint(addr, len, type)	\
-     (*current_target.to_remove_watchpoint) (addr, len, type)
+#define	target_remove_watchpoint(addr, len, type, cond) \
+     (*current_target.to_remove_watchpoint) (addr, len, type, cond)
 
 #define target_insert_hw_breakpoint(gdbarch, bp_tgt) \
      (*current_target.to_insert_hw_breakpoint) (gdbarch, bp_tgt)
@@ -1322,6 +1331,19 @@ extern char *normal_pid_to_str (ptid_t ptid);
 #define target_watchpoint_addr_within_range(target, addr, start, length) \
   (*target.to_watchpoint_addr_within_range) (target, addr, start, length)
 
+/* Return non-zero if the target is capable of using hardware to evaluate
+   the condition expression.  In this case, if the condition is false when
+   the watched memory location changes, execution may continue without the
+   debugger being notified.
+
+   Due to limitations in the hardware implementation, it may be capable of
+   avoiding triggering the watchpoint in some cases where the condition
+   expression is false, but may report some false positives as well.
+   For this reason, GDB will still evaluate the condition expression when
+   the watchpoint triggers.  */
+#define target_can_accel_watchpoint_condition(addr, len, type, cond) \
+  (*current_target.to_can_accel_watchpoint_condition) (addr, len, type, cond)
+
 /* Target can execute in reverse?  */
 #define target_can_execute_reverse \
      (current_target.to_can_execute_reverse ? \
diff --git a/gdb/value.c b/gdb/value.c
index edcd4d0ca74..d55240216b3 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -722,6 +722,20 @@ free_all_values (void)
   all_values = 0;
 }
 
+/* Frees all the elements in a chain of values.  */
+
+void
+free_value_chain (struct value *v)
+{
+  struct value *next;
+
+  for (; v; v = next)
+    {
+      next = value_next (v);
+      value_free (v);
+    }
+}
+
 /* Remove VAL from the chain all_values
    so it will not be freed automatically.  */
 
diff --git a/gdb/value.h b/gdb/value.h
index 0634bb9af40..12cbc0a702c 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -538,6 +538,10 @@ extern struct value *evaluate_subexp (struct type *expect_type,
 extern struct value *evaluate_subexpression_type (struct expression *exp,
 						  int subexp);
 
+extern void fetch_subexp_value (struct expression *exp, int *pc,
+				struct value **valp, struct value **resultp,
+				struct value **val_chain);
+
 extern char *extract_field_op (struct expression *exp, int *subexp);
 
 extern struct value *evaluate_subexp_with_coercion (struct expression *,
@@ -635,6 +639,8 @@ extern void value_free (struct value *val);
 
 extern void free_all_values (void);
 
+extern void free_value_chain (struct value *v);
+
 extern void release_value (struct value *val);
 
 extern int record_latest_value (struct value *val);