[PATCH 3/5] fbsd-nat: Pass an optional register base to the register set helpers.

[John Baldwin <jhb@FreeBSD.org>]

This is needed to permit using the helpers for register sets with a
variable base.  In particular regnum needs to be converted into a
relative register number before passed to regcache_map_supplies.
---
 gdb/fbsd-nat.c | 34 +++++++++++++++++++---------------
 gdb/fbsd-nat.h | 49 ++++++++++++++++++++++++++++---------------------
 2 files changed, 47 insertions(+), 36 deletions(-)

diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index 9d7383ac0ab..edcd3fc3ed1 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -1732,14 +1732,15 @@ fbsd_nat_target::supports_disable_randomization ()
 bool
 fbsd_nat_target::fetch_register_set (struct regcache *regcache, int regnum,
 				     int fetch_op, const struct regset *regset,
-				     void *regs, size_t size)
+				     int regbase, void *regs, size_t size)
 {
   const struct regcache_map_entry *map
     = (const struct regcache_map_entry *) regset->regmap;
   pid_t pid = get_ptrace_pid (regcache->ptid ());
 
-  if (regnum == -1 || regcache_map_supplies (map, regnum, regcache->arch(),
-					     size))
+  if (regnum == -1
+      || (regnum >= regbase && regcache_map_supplies (map, regnum - regbase,
+						      regcache->arch(), size)))
     {
       if (ptrace (fetch_op, pid, (PTRACE_TYPE_ARG3) regs, 0) == -1)
 	perror_with_name (_("Couldn't get registers"));
@@ -1755,15 +1756,16 @@ fbsd_nat_target::fetch_register_set (struct regcache *regcache, int regnum,
 bool
 fbsd_nat_target::store_register_set (struct regcache *regcache, int regnum,
 				     int fetch_op, int store_op,
-				     const struct regset *regset, void *regs,
-				     size_t size)
+				     const struct regset *regset, int regbase,
+				     void *regs, size_t size)
 {
   const struct regcache_map_entry *map
     = (const struct regcache_map_entry *) regset->regmap;
   pid_t pid = get_ptrace_pid (regcache->ptid ());
 
-  if (regnum == -1 || regcache_map_supplies (map, regnum, regcache->arch(),
-					     size))
+  if (regnum == -1
+      || (regnum >= regbase && regcache_map_supplies (map, regnum - regbase,
+						      regcache->arch(), size)))
     {
       if (ptrace (fetch_op, pid, (PTRACE_TYPE_ARG3) regs, 0) == -1)
 	perror_with_name (_("Couldn't get registers"));
@@ -1796,15 +1798,16 @@ fbsd_nat_target::have_regset (ptid_t ptid, int note)
 
 bool
 fbsd_nat_target::fetch_regset (struct regcache *regcache, int regnum, int note,
-			       const struct regset *regset, void *regs,
-			       size_t size)
+			       const struct regset *regset, int regbase,
+			       void *regs, size_t size)
 {
   const struct regcache_map_entry *map
     = (const struct regcache_map_entry *) regset->regmap;
   pid_t pid = get_ptrace_pid (regcache->ptid ());
 
-  if (regnum == -1 || regcache_map_supplies (map, regnum, regcache->arch(),
-					     size))
+  if (regnum == -1
+      || (regnum >= regbase && regcache_map_supplies (map, regnum - regbase,
+						      regcache->arch(), size)))
     {
       struct iovec iov;
 
@@ -1821,15 +1824,16 @@ fbsd_nat_target::fetch_regset (struct regcache *regcache, int regnum, int note,
 
 bool
 fbsd_nat_target::store_regset (struct regcache *regcache, int regnum, int note,
-			       const struct regset *regset, void *regs,
-			       size_t size)
+			       const struct regset *regset, int regbase,
+			       void *regs, size_t size)
 {
   const struct regcache_map_entry *map
     = (const struct regcache_map_entry *) regset->regmap;
   pid_t pid = get_ptrace_pid (regcache->ptid ());
 
-  if (regnum == -1 || regcache_map_supplies (map, regnum, regcache->arch(),
-					     size))
+  if (regnum == -1
+      || (regnum >= regbase && regcache_map_supplies (map, regnum - regbase,
+						      regcache->arch(), size)))
     {
       struct iovec iov;
 
diff --git a/gdb/fbsd-nat.h b/gdb/fbsd-nat.h
index 3a13bc8711f..22e47dcca0d 100644
--- a/gdb/fbsd-nat.h
+++ b/gdb/fbsd-nat.h
@@ -133,7 +133,8 @@ class fbsd_nat_target : public inf_ptrace_target
   /* Helper routines for use in fetch_registers and store_registers in
      subclasses.  These routines fetch and store a single set of
      registers described by REGSET.  The REGSET's 'regmap' field must
-     point to an array of 'struct regcache_map_entry'.
+     point to an array of 'struct regcache_map_entry'.  The valid
+     register numbers in the register map are relative to REGBASE.
 
      FETCH_OP is a ptrace operation to fetch the set of registers from
      a native thread.  STORE_OP is a ptrace operation to store the set
@@ -143,24 +144,27 @@ class fbsd_nat_target : public inf_ptrace_target
      and SIZE is the size of the storage.
 
      Returns true if the register set was transferred due to a
-     matching REGNUM.*/
+     matching REGNUM.  */
 
   bool fetch_register_set (struct regcache *regcache, int regnum, int fetch_op,
-			   const struct regset *regset, void *regs, size_t size);
+			   const struct regset *regset, int regbase, void *regs,
+			   size_t size);
 
   bool store_register_set (struct regcache *regcache, int regnum, int fetch_op,
 			   int store_op, const struct regset *regset,
-			   void *regs, size_t size);
+			   int regbase, void *regs, size_t size);
 
   /* Helper routines which use PT_GETREGSET and PT_SETREGSET for the
      specified NOTE instead of regset-specific fetch and store
      ops.  */
 
   bool fetch_regset (struct regcache *regcache, int regnum, int note,
-		     const struct regset *regset, void *regs, size_t size);
+		     const struct regset *regset, int regbase, void *regs,
+		     size_t size);
 
   bool store_regset (struct regcache *regcache, int regnum, int note,
-		     const struct regset *regset, void *regs, size_t size);
+		     const struct regset *regset, int regbase, void *regs,
+		     size_t size);
 
 protected:
   /* Wrapper versions of the above helpers which accept a register set
@@ -168,22 +172,23 @@ class fbsd_nat_target : public inf_ptrace_target
 
   template <class Regset>
   bool fetch_register_set (struct regcache *regcache, int regnum, int fetch_op,
-			   const struct regset *regset)
+			   const struct regset *regset, int regbase = 0)
   {
     Regset regs;
-    return fetch_register_set (regcache, regnum, fetch_op, regset, &regs,
-			       sizeof (regs));
-  }
-
-  template <class Regset>
-  bool store_register_set (struct regcache *regcache, int regnum, int fetch_op,
-			   int store_op, const struct regset *regset)
-  {
-    Regset regs;
-    return store_register_set (regcache, regnum, fetch_op, store_op, regset,
+    return fetch_register_set (regcache, regnum, fetch_op, regset, regbase,
 			       &regs, sizeof (regs));
   }
 
+  template <class Regset>
+  bool store_register_set (struct regcache *regcache, int regnum, int fetch_op,
+			   int store_op, const struct regset *regset,
+			   int regbase = 0)
+  {
+    Regset regs;
+    return store_register_set (regcache, regnum, fetch_op, store_op, regset,
+			       regbase, &regs, sizeof (regs));
+  }
+
   /* Helper routine for use in read_description in subclasses.  This
      routine checks if the register set for the specified NOTE is
      present for a given PTID.  If the register set is present, the
@@ -197,18 +202,20 @@ class fbsd_nat_target : public inf_ptrace_target
 
   template <class Regset>
   bool fetch_regset (struct regcache *regcache, int regnum, int note,
-		     const struct regset *regset)
+		     const struct regset *regset, int regbase = 0)
   {
     Regset regs;
-    return fetch_regset (regcache, regnum, note, regset, &regs, sizeof (regs));
+    return fetch_regset (regcache, regnum, note, regset, regbase, &regs,
+			 sizeof (regs));
   }
 
   template <class Regset>
   bool store_regset (struct regcache *regcache, int regnum, int note,
-		     const struct regset *regset)
+		     const struct regset *regset, int regbase = 0)
   {
     Regset regs;
-    return store_regset (regcache, regnum, note, regset, &regs, sizeof (regs));
+    return store_regset (regcache, regnum, note, regset, regbase, &regs,
+			 sizeof (regs));
   }
 };
 
-- 
2.36.1