[PATCH v5 4/7] Share regcache function regcache_raw_read_unsigned.

[Antoine Tremblay <antoine.tremblay@ericsson.com>]

In this v5:

* Change syscall_next_pc to use regcache and share the stack layout code
with GDB.
* Change is_thumb to be an operation rather than a variable
in arm_get_next_pcs.
* Remove arm_apcs32 from arm_get_next_pcs.
* Remove arm_gdb_get_next_pcs.

---

This patch is in preparation for software single step support on ARM in
GDBServer. It adds a new shared function regcache_raw_read_unsigned so
that GDB and GDBServer can use the same call to fetch a raw register into
an integer.

No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }

gdb/ChangeLog:
	* common/common-regcache.h (register_status) New enum.
	(regcache_raw_read_unsigned): New declaration.
	* regcache.h (enum register_status): Move to common-regcache.h.
	(regcache_raw_read_unsigned): Likewise.

gdb/gdbserver/ChangeLog:

	* regcache.c (init_register_cache): Initialize cache to
	REG_UNAVAILABLE.
	(regcache_raw_read_unsigned): New function.
	* regcache.h (REG_UNAVAILABLE, REG_VALID): Replaced by shared
	register_status enum.
---
 gdb/common/common-regcache.h | 22 ++++++++++++++++++++++
 gdb/gdbserver/regcache.c     | 26 ++++++++++++++++++++++++--
 gdb/gdbserver/regcache.h     |  7 -------
 gdb/regcache.h               | 21 ---------------------
 4 files changed, 46 insertions(+), 30 deletions(-)

diff --git a/gdb/common/common-regcache.h b/gdb/common/common-regcache.h
index c470603..3dca30a 100644
--- a/gdb/common/common-regcache.h
+++ b/gdb/common/common-regcache.h
@@ -22,6 +22,24 @@
 
 /* This header is a stopgap until we have an independent regcache.  */
 
+enum register_status
+  {
+    /* The register value is not in the cache, and we don't know yet
+       whether it's available in the target (or traceframe).  */
+    REG_UNKNOWN = 0,
+
+    /* The register value is valid and cached.  */
+    REG_VALID = 1,
+
+    /* The register value is unavailable.  E.g., we're inspecting a
+       traceframe, and this register wasn't collected.  Note that this
+       is different a different "unavailable" from saying the register
+       does not exist in the target's architecture --- in that case,
+       the target should have given us a target description that does
+       not include the register in the first place.  */
+    REG_UNAVAILABLE = -1
+  };
+
 /* Return a pointer to the register cache associated with the
    thread specified by PTID.  This function must be provided by
    the client.  */
@@ -38,4 +56,8 @@ extern int regcache_register_size (const struct regcache *regcache, int n);
 
 extern CORE_ADDR regcache_read_pc (struct regcache *regcache);
 
+/* Read a raw register into a unsigned integer.  */
+extern enum register_status regcache_raw_read_unsigned
+  (struct regcache *regcache, int regnum, ULONGEST *val);
+
 #endif /* COMMON_REGCACHE_H */
diff --git a/gdb/gdbserver/regcache.c b/gdb/gdbserver/regcache.c
index b9311fe..c608bf3 100644
--- a/gdb/gdbserver/regcache.c
+++ b/gdb/gdbserver/regcache.c
@@ -145,8 +145,9 @@ init_register_cache (struct regcache *regcache,
 	= (unsigned char *) xcalloc (1, tdesc->registers_size);
       regcache->registers_owned = 1;
       regcache->register_status
-	= (unsigned char *) xcalloc (1, tdesc->num_registers);
-      gdb_assert (REG_UNAVAILABLE == 0);
+	= (unsigned char *) xmalloc (tdesc->num_registers);
+      memset ((void *) regcache->register_status, REG_UNAVAILABLE,
+	      tdesc->num_registers);
 #else
       gdb_assert_not_reached ("can't allocate memory from the heap");
 #endif
@@ -435,6 +436,27 @@ collect_register (struct regcache *regcache, int n, void *buf)
 	  register_size (regcache->tdesc, n));
 }
 
+enum register_status
+regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
+			    ULONGEST *val)
+{
+  int size;
+
+  gdb_assert (regcache != NULL);
+  gdb_assert (regnum >= 0 && regnum < regcache->tdesc->num_registers);
+
+  size = register_size (regcache->tdesc, regnum);
+
+  if (size > (int) sizeof (ULONGEST))
+    error (_("That operation is not available on integers of more than"
+            "%d bytes."),
+          (int) sizeof (ULONGEST));
+
+  collect_register (regcache, regnum, val);
+
+  return REG_VALID;
+}
+
 #ifndef IN_PROCESS_AGENT
 
 void
diff --git a/gdb/gdbserver/regcache.h b/gdb/gdbserver/regcache.h
index a0be95e..f4b798b 100644
--- a/gdb/gdbserver/regcache.h
+++ b/gdb/gdbserver/regcache.h
@@ -24,13 +24,6 @@
 struct thread_info;
 struct target_desc;
 
-/* The register exists, it has a value, but we don't know what it is.
-   Used when inspecting traceframes.  */
-#define REG_UNAVAILABLE 0
-
-/* We know the register's value (and we have it cached).  */
-#define REG_VALID 1
-
 /* The data for the register cache.  Note that we have one per
    inferior; this is primarily for simplicity, as the performance
    benefit is minimal.  */
diff --git a/gdb/regcache.h b/gdb/regcache.h
index a9fb44b..76de9e8 100644
--- a/gdb/regcache.h
+++ b/gdb/regcache.h
@@ -47,24 +47,6 @@ extern struct gdbarch *get_regcache_arch (const struct regcache *regcache);
 
 extern struct address_space *get_regcache_aspace (const struct regcache *);
 
-enum register_status
-  {
-    /* The register value is not in the cache, and we don't know yet
-       whether it's available in the target (or traceframe).  */
-    REG_UNKNOWN = 0,
-
-    /* The register value is valid and cached.  */
-    REG_VALID = 1,
-
-    /* The register value is unavailable.  E.g., we're inspecting a
-       traceframe, and this register wasn't collected.  Note that this
-       is different a different "unavailable" from saying the register
-       does not exist in the target's architecture --- in that case,
-       the target should have given us a target description that does
-       not include the register in the first place.  */
-    REG_UNAVAILABLE = -1
-  };
-
 enum register_status regcache_register_status (const struct regcache *regcache,
 					       int regnum);
 
@@ -78,9 +60,6 @@ void regcache_raw_write (struct regcache *regcache, int rawnum,
 extern enum register_status
   regcache_raw_read_signed (struct regcache *regcache,
 			    int regnum, LONGEST *val);
-extern enum register_status
-  regcache_raw_read_unsigned (struct regcache *regcache,
-			      int regnum, ULONGEST *val);
 extern void regcache_raw_write_signed (struct regcache *regcache,
 				       int regnum, LONGEST val);
 extern void regcache_raw_write_unsigned (struct regcache *regcache,
-- 
2.6.3