Add regcache raw_supply_integer and raw_collect_integer.

Use these to replace instances of MAX_REGISTER_SIZE.

	* defs.h (copy_integer_to_size): New declaration.
	* findvar.c (copy_integer_to_size): New function.
	(do_cint_test): New selftest function.
	(copy_integer_to_size_test): Likewise.
	(_initialize_findvar): Likewise.
	* mips-fbsd-tdep.c (mips_fbsd_supply_reg): Use raw_supply_integer.
	(mips_fbsd_collect_reg): Use raw_collect_integer.
	* mips-linux-tdep.c (supply_32bit_reg): Use raw_supply_integer.
	(mips64_fill_gregset): Use raw_collect_integer
	(mips64_fill_fpregset): Use raw_supply_integer.
	* regcache.c (regcache::raw_supply_integer): New function.
	(regcache::raw_collect_integer): Likewise.
	* regcache.h: (regcache::raw_supply_integer): New declaration.
	(regcache::raw_collect_integer): Likewise.

gdb/findvar.c

@@ -33,6 +33,7 @@
 #include "objfiles.h"
 #include "language.h"
 #include "dwarf2loc.h"
+#include "selftest.h"
 
 /* Basic byte-swapping routines.  All 'extract' functions return a
    host-format integer from a target-format integer at ADDR which is
@@ -249,7 +250,46 @@ store_typed_address (gdb_byte *buf, struct type *type, CORE_ADDR addr)
   gdbarch_address_to_pointer (get_type_arch (type), type, buf, addr);
 }
 
+/* Copy a value from SOURCE of size SOURCE_SIZE bytes to DEST of size DEST_SIZE
+   bytes.  If SOURCE_SIZE is greater than DEST_SIZE, then truncate the most
+   significant bytes.  If SOURCE_SIZE is less than DEST_SIZE then either sign
+   or zero extended according to IS_SIGNED.  Values are stored in memory with
+   endianess BYTE_ORDER.  */
 
+void
+copy_integer_to_size (gdb_byte *dest, int dest_size, const gdb_byte *source,
+		      int source_size, bool is_signed,
+		      enum bfd_endian byte_order)
+{
+  signed int size_diff = dest_size - source_size;
+
+  /* Copy across everything from SOURCE that can fit into DEST.  */
+
+  if (byte_order == BFD_ENDIAN_BIG && size_diff > 0)
+    memcpy (dest + size_diff, source, source_size);
+  else if (byte_order == BFD_ENDIAN_BIG && size_diff < 0)
+    memcpy (dest, source - size_diff, dest_size);
+  else
+    memcpy (dest, source, std::min (source_size, dest_size));
+
+  /* Fill the remaining space in DEST by either zero extending or sign
+     extending.  */
+
+  if (size_diff > 0)
+    {
+      gdb_byte extension = 0;
+      if (is_signed
+	  && ((byte_order != BFD_ENDIAN_BIG && source[source_size - 1] & 0x80)
+	      || (byte_order == BFD_ENDIAN_BIG && source[0] & 0x80)))
+	extension = 0xff;
+
+      /* Extend into MSBs of SOURCE.  */
+      if (byte_order == BFD_ENDIAN_BIG)
+	memset (dest, extension, size_diff);
+      else
+	memset (dest + source_size, extension, size_diff);
+    }
+}
 
 /* Return a `value' with the contents of (virtual or cooked) register
    REGNUM as found in the specified FRAME.  The register's type is
@@ -1005,3 +1045,91 @@ address_from_register (int regnum, struct frame_info *frame)
   return result;
 }
 
+#if GDB_SELF_TEST
+namespace selftests {
+namespace findvar_tests {
+
+/* Function to test copy_integer_to_size.  Store SOURCE_VAL with size
+   SOURCE_SIZE to a buffer, making sure no sign extending happens at this
+   stage.  Copy buffer to a new buffer using copy_integer_to_size.  Extract
+   copied value and compare to DEST_VALU.  Copy again with a signed
+   copy_integer_to_size and compare to DEST_VALS.  Do everything for both
+   LITTLE and BIG target endians.  Use unsigned values throughout to make
+   sure there are no implicit sign extensions.  */
+
+static void
+do_cint_test (ULONGEST dest_valu, ULONGEST dest_vals, int dest_size,
+	      ULONGEST src_val, int src_size)
+{
+  for (int i = 0; i < 2 ; i++)
+    {
+      gdb_byte srcbuf[sizeof (ULONGEST)] = {};
+      gdb_byte destbuf[sizeof (ULONGEST)] = {};
+      enum bfd_endian byte_order = i ? BFD_ENDIAN_BIG : BFD_ENDIAN_LITTLE;
+
+      /* Fill the src buffer (and later the dest buffer) with non-zero junk,
+	 to ensure zero extensions aren't hidden.  */
+      memset (srcbuf, 0xaa, sizeof (srcbuf));
+
+      /* Store (and later extract) using unsigned to ensure there are no sign
+	 extensions.  */
+      store_unsigned_integer (srcbuf, src_size, byte_order, src_val);
+
+      /* Test unsigned.  */
+      memset (destbuf, 0xaa, sizeof (destbuf));
+      copy_integer_to_size (destbuf, dest_size, srcbuf, src_size, false,
+			    byte_order);
+      SELF_CHECK (dest_valu == extract_unsigned_integer (destbuf, dest_size,
+							 byte_order));
+
+      /* Test signed.  */
+      memset (destbuf, 0xaa, sizeof (destbuf));
+      copy_integer_to_size (destbuf, dest_size, srcbuf, src_size, true,
+			    byte_order);
+      SELF_CHECK (dest_vals == extract_unsigned_integer (destbuf, dest_size,
+							 byte_order));
+    }
+}
+
+static void
+copy_integer_to_size_test ()
+{
+  /* Destination is bigger than the source, which has the signed bit unset.  */
+  do_cint_test (0x12345678, 0x12345678, 8, 0x12345678, 4);
+  do_cint_test (0x345678, 0x345678, 8, 0x12345678, 3);
+
+  /* Destination is bigger than the source, which has the signed bit set.  */
+  do_cint_test (0xdeadbeef, 0xffffffffdeadbeef, 8, 0xdeadbeef, 4);
+  do_cint_test (0xadbeef, 0xffffffffffadbeef, 8, 0xdeadbeef, 3);
+
+  /* Destination is smaller than the source.  */
+  do_cint_test (0x5678, 0x5678, 2, 0x12345678, 3);
+  do_cint_test (0xbeef, 0xbeef, 2, 0xdeadbeef, 3);
+
+  /* Destination and source are the same size.  */
+  do_cint_test (0x8765432112345678, 0x8765432112345678, 8, 0x8765432112345678,
+		8);
+  do_cint_test (0x432112345678, 0x432112345678, 6, 0x8765432112345678, 6);
+  do_cint_test (0xfeedbeaddeadbeef, 0xfeedbeaddeadbeef, 8, 0xfeedbeaddeadbeef,
+		8);
+  do_cint_test (0xbeaddeadbeef, 0xbeaddeadbeef, 6, 0xfeedbeaddeadbeef, 6);
+
+  /* Destination is bigger than the source.  Source is bigger than 32bits.  */
+  do_cint_test (0x3412345678, 0x3412345678, 8, 0x3412345678, 6);
+  do_cint_test (0xff12345678, 0xff12345678, 8, 0xff12345678, 6);
+  do_cint_test (0x432112345678, 0x432112345678, 8, 0x8765432112345678, 6);
+  do_cint_test (0xff2112345678, 0xffffff2112345678, 8, 0xffffff2112345678, 6);
+}
+
+} // namespace findvar_test
+} // namespace selftests
+
+#endif
+
+void
+_initialize_findvar (void)
+{
+#if GDB_SELF_TEST
+  register_self_test (selftests::findvar_tests::copy_integer_to_size_test);
+#endif
+}