Adjust byte order variable display/change if DW_AT_endianity is present.

- Rationale:
It is possible for compilers to indicate the desired byte order
interpretation of scalar variables using the DWARF attribute:
   DW_AT_endianity

A type flagged with this variable would typically use one of:
   DW_END_big
   DW_END_little
which instructs the debugger what the desired byte order interpretation
of the variable should be.

The GCC compiler (as of V6) has a mechanism for setting the desired byte
ordering of the fields within a structure or union.  For, example, on a
little endian target, a structure declared as:
   struct big {
       int v;
       short a[4];
   } __attribute__( ( scalar_storage_order( "big-endian" ) ) );
could be used to ensure all the structure members have a big-endian
interpretation (the compiler would automatically insert byte swap
instructions before and after respective store and load instructions).

- To reproduce
GCC V8 is required to correctly emit DW_AT_endianity DWARF attributes
in all situations when the scalar_storage_order attribute is used.

A fix for (dwarf endianity instrumentation) for GCC V6-V7 can be found
in the URL field of the following PR:
   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82509

- Test-case:
A new test case (testsuite/gdb.base/endianity.*) is included with this
patch.

Manual testing for mixed endianity code has also been done with GCC V8.
See:
   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82509#c4

- Observed vs. expected:

Without this change, using scalar_storage_order that doesn't match the
target, such as

struct otherendian
{
  int v;
} __attribute__( ( scalar_storage_order( "big-endian" ) ) );

would behave like the following on a little endian target:

   Breakpoint 1 at 0x401135: file endianity.c, line 41.
   (gdb) run
   Starting program: /home/pjoot/freeware/t/a.out
   Missing separate debuginfos, use: debuginfo-install glibc-2.17-292.el7.x86_64

   Breakpoint 1, main () at endianity.c:41
   41        struct otherendian o = {3};
   (gdb) n
   43        do_nothing (&o); /* START */
   (gdb) p o
   $1 = {v = 50331648}
   (gdb) p /x
   $2 = {v = 0x3000000}

whereas with this gdb enhancement we can access the variable with the user
specified endianity:

   Breakpoint 1, main () at endianity.c:41
   41        struct otherendian o = {3};
   (gdb) p o
   $1 = {v = 0}
   (gdb) n
   43        do_nothing (&o); /* START */
   (gdb) p o
   $2 = {v = 3}
   (gdb) p o.v = 4
   $3 = 4
   (gdb) p o.v
   $4 = 4
   (gdb) x/4xb &o.v
   0x7fffffffd90c: 0x00    0x00    0x00    0x04

(observe that the 4 byte int variable has a big endian representation in the
 hex dump.)

gdb/ChangeLog
2019-11-21  Peeter Joot  <peeter.joot@lzlabs.com>

	Byte reverse display of variables with DW_END_big, DW_END_little
	(DW_AT_endianity) dwarf attributes if different than the native
	byte order.
	* ada-lang.c (ada_value_binop):
	Use type_byte_order instead of gdbarch_byte_order.
	* ada-valprint.c (printstr):
	(ada_val_print_string):
	* ada-lang.c (value_pointer):
	(ada_value_binop):
	Use type_byte_order instead of gdbarch_byte_order.
	* c-lang.c (c_get_string):
	Use type_byte_order instead of gdbarch_byte_order.
	* c-valprint.c (c_val_print_array):
	Use type_byte_order instead of gdbarch_byte_order.
	* cp-valprint.c (cp_print_class_member):
	Use type_byte_order instead of gdbarch_byte_order.
	* dwarf2loc.c (rw_pieced_value):
	Use type_byte_order instead of gdbarch_byte_order.
	* dwarf2read.c (read_base_type): Handle DW_END_big,
	DW_END_little
	* f-lang.c (f_get_encoding):
	Use type_byte_order instead of gdbarch_byte_order.
	* findvar.c (default_read_var_value):
	Use type_byte_order instead of gdbarch_byte_order.
	* gdbtypes.c (check_types_equal):
	Require matching TYPE_ENDIANITY_NOT_DEFAULT if set.
	(recursive_dump_type): Print TYPE_ENDIANITY_BIG,
	and TYPE_ENDIANITY_LITTLE if set.
	(type_byte_order): new function.
	* gdbtypes.h (TYPE_ENDIANITY_NOT_DEFAULT): New macro.
	(struct main_type) <flag_endianity_not_default>:
	New field.
	(type_byte_order): New function.
	* infcmd.c (default_print_one_register_info):
	Use type_byte_order instead of gdbarch_byte_order.
	* p-lang.c (pascal_printstr):
	Use type_byte_order instead of gdbarch_byte_order.
	* p-valprint.c (pascal_val_print):
	Use type_byte_order instead of gdbarch_byte_order.
	* printcmd.c (print_scalar_formatted):
	Use type_byte_order instead of gdbarch_byte_order.
	* solib-darwin.c (darwin_current_sos):
	Use type_byte_order instead of gdbarch_byte_order.
	* solib-svr4.c (solib_svr4_r_ldsomap):
	Use type_byte_order instead of gdbarch_byte_order.
	* stap-probe.c (stap_modify_semaphore):
	Use type_byte_order instead of gdbarch_byte_order.
	* target-float.c (target_float_same_format_p):
	Use type_byte_order instead of gdbarch_byte_order.
	* valarith.c (scalar_binop):
	(value_bit_index):
	Use type_byte_order instead of gdbarch_byte_order.
	* valops.c (value_cast):
	Use type_byte_order instead of gdbarch_byte_order.
	* valprint.c (generic_emit_char):
	(generic_printstr):
	(val_print_string):
	Use type_byte_order instead of gdbarch_byte_order.
	* value.c (unpack_long):
	(unpack_bits_as_long):
	(unpack_value_bitfield):
	(modify_field):
	(pack_long):
	(pack_unsigned_long):
	Use type_byte_order instead of gdbarch_byte_order.
	* findvar.c (unsigned_pointer_to_address):
	(signed_pointer_to_address):
	(unsigned_address_to_pointer):
	(address_to_signed_pointer):
	(default_read_var_value):
	(default_value_from_register):
	Use type_byte_order instead of gdbarch_byte_order.
	* gnu-v3-abi.c (gnuv3_make_method_ptr):
	Use type_byte_order instead of gdbarch_byte_order.
	* riscv-tdep.c (riscv_print_one_register_info):
	Use type_byte_order instead of gdbarch_byte_order.

gdb/testsuite/ChangeLog
2019-11-21  Peeter Joot  <peeter.joot@lzlabs.com>

	* gdb.base/endianity.c: New test.
	* gdb.base/endianity.exp: New file.

Change-Id: I4bd98c1b4508c2d7c5a5dbb15d7b7b1cb4e667e2

29 files changed, 269 insertions, 58 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 57e8f6b..0249048 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,82 @@
+2019-11-21  Peeter Joot  <peeter.joot@lzlabs.com>
+
+	Byte reverse display of variables with DW_END_big, DW_END_little
+	(DW_AT_endianity) dwarf attributes if different than the native
+	byte order.
+	* ada-lang.c (ada_value_binop):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* ada-valprint.c (printstr):
+	(ada_val_print_string):
+	* ada-lang.c (value_pointer):
+	(ada_value_binop):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* c-lang.c (c_get_string):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* c-valprint.c (c_val_print_array):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* cp-valprint.c (cp_print_class_member):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* dwarf2loc.c (rw_pieced_value):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* dwarf2read.c (read_base_type): Handle DW_END_big,
+	DW_END_little
+	* f-lang.c (f_get_encoding):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* findvar.c (default_read_var_value):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* gdbtypes.c (check_types_equal):
+	Require matching TYPE_ENDIANITY_NOT_DEFAULT if set.
+	(recursive_dump_type): Print TYPE_ENDIANITY_BIG,
+	and TYPE_ENDIANITY_LITTLE if set.
+	(type_byte_order): new function.
+	* gdbtypes.h (TYPE_ENDIANITY_NOT_DEFAULT): New macro.
+	(struct main_type) <flag_endianity_not_default>:
+	New field.
+	(type_byte_order): New function.
+	* infcmd.c (default_print_one_register_info):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* p-lang.c (pascal_printstr):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* p-valprint.c (pascal_val_print):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* printcmd.c (print_scalar_formatted):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* solib-darwin.c (darwin_current_sos):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* solib-svr4.c (solib_svr4_r_ldsomap):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* stap-probe.c (stap_modify_semaphore):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* target-float.c (target_float_same_format_p):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* valarith.c (scalar_binop):
+	(value_bit_index):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* valops.c (value_cast):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* valprint.c (generic_emit_char):
+	(generic_printstr):
+	(val_print_string):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* value.c (unpack_long):
+	(unpack_bits_as_long):
+	(unpack_value_bitfield):
+	(modify_field):
+	(pack_long):
+	(pack_unsigned_long):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* findvar.c (unsigned_pointer_to_address):
+	(signed_pointer_to_address):
+	(unsigned_address_to_pointer):
+	(address_to_signed_pointer):
+	(default_read_var_value):
+	(default_value_from_register):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* gnu-v3-abi.c (gnuv3_make_method_ptr):
+	Use type_byte_order instead of gdbarch_byte_order.
+	* riscv-tdep.c (riscv_print_one_register_info):
+	Use type_byte_order instead of gdbarch_byte_order.
+
 2019-11-21  Simon Marchi  <simon.marchi@polymtl.ca>
 
 	* top.c (current_ui_gdb_stdout_ptr): Spell out by hand.
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 2935df5..36001ef 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -4546,7 +4546,7 @@ value_pointer (struct value *value, struct type *type)
 
   addr = value_address (value);
   gdbarch_address_to_pointer (gdbarch, type, buf, addr);
-  addr = extract_unsigned_integer (buf, len, gdbarch_byte_order (gdbarch));
+  addr = extract_unsigned_integer (buf, len, type_byte_order (type));
   return addr;
 }
 
@@ -9678,7 +9678,7 @@ ada_value_binop (struct value *arg1, struct value *arg2, enum exp_opcode op)
   val = allocate_value (type1);
   store_unsigned_integer (value_contents_raw (val),
                           TYPE_LENGTH (value_type (val)),
-			  gdbarch_byte_order (get_type_arch (type1)), v);
+			  type_byte_order (type1), v);
   return val;
 }
 
diff --git a/gdb/ada-valprint.c b/gdb/ada-valprint.c
index 5ab0365..4bb9247 100644
--- a/gdb/ada-valprint.c
+++ b/gdb/ada-valprint.c
@@ -476,7 +476,7 @@ printstr (struct ui_file *stream, struct type *elttype, const gdb_byte *string,
 	  unsigned int length, int force_ellipses, int type_len,
 	  const struct value_print_options *options)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (elttype));
+  enum bfd_endian byte_order = type_byte_order (elttype);
   unsigned int i;
   unsigned int things_printed = 0;
   int in_quotes = 0;
@@ -719,7 +719,7 @@ ada_val_print_string (struct type *type, const gdb_byte *valaddr,
 		      struct value *original_value,
 		      const struct value_print_options *options)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
+  enum bfd_endian byte_order = type_byte_order (type);
   struct type *elttype = TYPE_TARGET_TYPE (type);
   unsigned int eltlen;
   unsigned int len;
diff --git a/gdb/c-lang.c b/gdb/c-lang.c
index 74e3f73..1de44f7 100644
--- a/gdb/c-lang.c
+++ b/gdb/c-lang.c
@@ -245,7 +245,7 @@ c_get_string (struct value *value, gdb::unique_xmalloc_ptr<gdb_byte> *buffer,
   struct type *element_type = TYPE_TARGET_TYPE (type);
   int req_length = *length;
   enum bfd_endian byte_order
-    = gdbarch_byte_order (get_type_arch (type));
+    = type_byte_order (type);
 
   if (element_type == NULL)
     goto error;
diff --git a/gdb/c-valprint.c b/gdb/c-valprint.c
index c4306f1..58675f6 100644
--- a/gdb/c-valprint.c
+++ b/gdb/c-valprint.c
@@ -247,8 +247,7 @@ c_val_print_array (struct type *type, const gdb_byte *valaddr,
     {
       LONGEST low_bound, high_bound;
       int eltlen, len;
-      struct gdbarch *gdbarch = get_type_arch (type);
-      enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+      enum bfd_endian byte_order = type_byte_order (type);
       unsigned int i = 0;	/* Number of characters printed.  */
 
       if (!get_array_bounds (type, &low_bound, &high_bound))
diff --git a/gdb/cp-valprint.c b/gdb/cp-valprint.c
index 04be4dc..e445d42 100644
--- a/gdb/cp-valprint.c
+++ b/gdb/cp-valprint.c
@@ -740,7 +740,7 @@ void
 cp_print_class_member (const gdb_byte *valaddr, struct type *type,
 		       struct ui_file *stream, const char *prefix)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
+  enum bfd_endian byte_order = type_byte_order (type);
 
   /* VAL is a byte offset into the structure type SELF_TYPE.
      Find the name of the field for that offset and
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index c8ba029..e25ee66 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -1601,7 +1601,7 @@ rw_pieced_value (struct value *v, struct value *from)
       bits_to_skip += (8 * value_offset (value_parent (v))
 		       + value_bitpos (v));
       if (from != NULL
-	  && (gdbarch_byte_order (get_type_arch (value_type (from)))
+	  && (type_byte_order (value_type (from))
 	      == BFD_ENDIAN_BIG))
 	{
 	  /* Use the least significant bits of FROM.  */
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 9178e0e..d89a541 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -17661,24 +17661,24 @@ read_base_type (struct die_info *die, struct dwarf2_cu *cu)
   struct type *type;
   struct attribute *attr;
   int encoding = 0, bits = 0;
+  int endianity = 0;
   const char *name;
+  gdbarch *arch;
 
   attr = dwarf2_attr (die, DW_AT_encoding, cu);
   if (attr != nullptr)
-    {
-      encoding = DW_UNSND (attr);
-    }
+    encoding = DW_UNSND (attr);
   attr = dwarf2_attr (die, DW_AT_byte_size, cu);
   if (attr != nullptr)
-    {
-      bits = DW_UNSND (attr) * TARGET_CHAR_BIT;
-    }
+    bits = DW_UNSND (attr) * TARGET_CHAR_BIT;
   name = dwarf2_name (die, cu);
   if (!name)
-    {
-      complaint (_("DW_AT_name missing from DW_TAG_base_type"));
-    }
+    complaint (_("DW_AT_name missing from DW_TAG_base_type"));
+  attr = dwarf2_attr (die, DW_AT_endianity, cu);
+  if (attr)
+    endianity = DW_UNSND (attr);
 
+  arch = get_objfile_arch (objfile);
   switch (encoding)
     {
       case DW_ATE_address:
@@ -17729,8 +17729,6 @@ read_base_type (struct die_info *die, struct dwarf2_cu *cu)
 	break;
       case DW_ATE_UTF:
 	{
-	  gdbarch *arch = get_objfile_arch (objfile);
-
 	  if (bits == 16)
 	    type = builtin_type (arch)->builtin_char16;
 	  else if (bits == 32)
@@ -17757,6 +17755,18 @@ read_base_type (struct die_info *die, struct dwarf2_cu *cu)
 
   maybe_set_alignment (cu, die, type);
 
+  switch (endianity)
+    {
+      case DW_END_big:
+        if (gdbarch_byte_order (arch) == BFD_ENDIAN_LITTLE)
+          TYPE_ENDIANITY_NOT_DEFAULT (type) = 1;
+        break;
+      case DW_END_little:
+        if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG)
+          TYPE_ENDIANITY_NOT_DEFAULT (type) = 1;
+        break;
+    }
+
   return set_die_type (die, type, cu);
 }
 
diff --git a/gdb/f-lang.c b/gdb/f-lang.c
index 7f241c6..fd4ad0f 100644
--- a/gdb/f-lang.c
+++ b/gdb/f-lang.c
@@ -59,7 +59,7 @@ f_get_encoding (struct type *type)
       encoding = target_charset (get_type_arch (type));
       break;
     case 4:
-      if (gdbarch_byte_order (get_type_arch (type)) == BFD_ENDIAN_BIG)
+      if (type_byte_order (type) == BFD_ENDIAN_BIG)
 	encoding = "UTF-32BE";
       else
 	encoding = "UTF-32LE";
diff --git a/gdb/findvar.c b/gdb/findvar.c
index bbfd689..95cc58d 100644
--- a/gdb/findvar.c
+++ b/gdb/findvar.c
@@ -309,7 +309,7 @@ CORE_ADDR
 unsigned_pointer_to_address (struct gdbarch *gdbarch,
 			     struct type *type, const gdb_byte *buf)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  enum bfd_endian byte_order = type_byte_order (type);
 
   return extract_unsigned_integer (buf, TYPE_LENGTH (type), byte_order);
 }
@@ -318,7 +318,7 @@ CORE_ADDR
 signed_pointer_to_address (struct gdbarch *gdbarch,
 			   struct type *type, const gdb_byte *buf)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  enum bfd_endian byte_order = type_byte_order (type);
 
   return extract_signed_integer (buf, TYPE_LENGTH (type), byte_order);
 }
@@ -329,7 +329,7 @@ void
 unsigned_address_to_pointer (struct gdbarch *gdbarch, struct type *type,
 			     gdb_byte *buf, CORE_ADDR addr)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  enum bfd_endian byte_order = type_byte_order (type);
 
   store_unsigned_integer (buf, TYPE_LENGTH (type), byte_order, addr);
 }
@@ -338,7 +338,7 @@ void
 address_to_signed_pointer (struct gdbarch *gdbarch, struct type *type,
 			   gdb_byte *buf, CORE_ADDR addr)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  enum bfd_endian byte_order = type_byte_order (type);
 
   store_signed_integer (buf, TYPE_LENGTH (type), byte_order, addr);
 }
@@ -620,7 +620,7 @@ default_read_var_value (struct symbol *var, const struct block *var_block,
       /* Put the constant back in target format. */
       v = allocate_value (type);
       store_signed_integer (value_contents_raw (v), TYPE_LENGTH (type),
-			    gdbarch_byte_order (get_type_arch (type)),
+			    type_byte_order (type),
 			    (LONGEST) SYMBOL_VALUE (var));
       VALUE_LVAL (v) = not_lval;
       return v;
@@ -840,7 +840,7 @@ default_value_from_register (struct gdbarch *gdbarch, struct type *type,
      an integral number of registers.  Otherwise, you need to do
      some fiddling with the last register copied here for little
      endian machines.  */
-  if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG
+  if (type_byte_order (type) == BFD_ENDIAN_BIG
       && len < register_size (gdbarch, regnum))
     /* Big-endian, and we want less than full size.  */
     set_value_offset (value, register_size (gdbarch, regnum) - len);
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index fd1c765..31c1a7b 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -3616,6 +3616,7 @@ check_types_equal (struct type *type1, struct type *type2,
       || TYPE_LENGTH (type1) != TYPE_LENGTH (type2)
       || TYPE_UNSIGNED (type1) != TYPE_UNSIGNED (type2)
       || TYPE_NOSIGN (type1) != TYPE_NOSIGN (type2)
+      || TYPE_ENDIANITY_NOT_DEFAULT (type1) != TYPE_ENDIANITY_NOT_DEFAULT (type2)
       || TYPE_VARARGS (type1) != TYPE_VARARGS (type2)
       || TYPE_VECTOR (type1) != TYPE_VECTOR (type2)
       || TYPE_NOTTEXT (type1) != TYPE_NOTTEXT (type2)
@@ -4669,6 +4670,10 @@ recursive_dump_type (struct type *type, int spaces)
     {
       puts_filtered (" TYPE_NOSIGN");
     }
+  if (TYPE_ENDIANITY_NOT_DEFAULT (type))
+    {
+      puts_filtered (" TYPE_ENDIANITY_NOT_DEFAULT");
+    }
   if (TYPE_STUB (type))
     {
       puts_filtered (" TYPE_STUB");
@@ -5617,3 +5622,21 @@ _initialize_gdbtypes (void)
 			   show_strict_type_checking,
 			   &setchecklist, &showchecklist);
 }
+
+/* See gdbtypes.h.  */
+enum bfd_endian
+type_byte_order (const struct type *type)
+{
+  bfd_endian byteorder = gdbarch_byte_order (get_type_arch (type));
+  if (TYPE_ENDIANITY_NOT_DEFAULT (type))
+    {
+      if (byteorder == BFD_ENDIAN_BIG)
+        return BFD_ENDIAN_LITTLE;
+      else if (byteorder == BFD_ENDIAN_LITTLE)
+        return BFD_ENDIAN_BIG;
+      else
+        return BFD_ENDIAN_UNKNOWN;
+    }
+
+  return byteorder;
+}
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index 6d6ff59..8fc770c 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -219,6 +219,12 @@ DEF_ENUM_FLAGS_TYPE (enum type_instance_flag_value, type_instance_flags);
 
 #define TYPE_NOSIGN(t)		(TYPE_MAIN_TYPE (t)->flag_nosign)
 
+/* * A compiler may supply dwarf instrumentation
+   that indicates the desired endian interpretation of the variable
+   differs from the native endian representation. */
+
+#define TYPE_ENDIANITY_NOT_DEFAULT(t) (TYPE_MAIN_TYPE (t)->flag_endianity_not_default)
+
 /* * This appears in a type's flags word if it is a stub type (e.g.,
    if someone referenced a type that wasn't defined in a source file
    via (struct sir_not_appearing_in_this_film *)).  */
@@ -701,6 +707,7 @@ struct main_type
   unsigned int flag_gnu_ifunc : 1;
   unsigned int flag_fixed_instance : 1;
   unsigned int flag_objfile_owned : 1;
+  unsigned int flag_endianity_not_default : 1;
 
   /* * True if this type was declared with "class" rather than
      "struct".  */
@@ -2146,6 +2153,12 @@ extern int type_not_allocated (const struct type *type);
 
 extern int type_not_associated (const struct type *type);
 
+/* * When the type includes explicit byte ordering, return that.
+   Otherwise, the byte ordering from gdbarch_byte_order for 
+   get_type_arch is returned.  */
+   
+extern enum bfd_endian type_byte_order (const struct type *type);
+
 /* A flag to enable printing of debugging information of C++
    overloading.  */
 
diff --git a/gdb/gnu-v3-abi.c b/gdb/gnu-v3-abi.c
index 2533a94..2a5486c 100644
--- a/gdb/gnu-v3-abi.c
+++ b/gdb/gnu-v3-abi.c
@@ -678,7 +678,7 @@ gnuv3_make_method_ptr (struct type *type, gdb_byte *contents,
 {
   struct gdbarch *gdbarch = get_type_arch (type);
   int size = TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr);
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  enum bfd_endian byte_order = type_byte_order (type);
 
   /* FIXME drow/2006-12-24: The adjustment of "this" is currently
      always zero, since the method pointer is of the correct type.
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 5ca9933..eb18efa 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -2216,7 +2216,7 @@ default_print_one_register_info (struct ui_file *file,
     {
       struct value_print_options opts;
       const gdb_byte *valaddr = value_contents_for_printing (val);
-      enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (regtype));
+      enum bfd_endian byte_order = type_byte_order (regtype);
 
       get_user_print_options (&opts);
       opts.deref_ref = 1;
diff --git a/gdb/p-lang.c b/gdb/p-lang.c
index 0cf1c6c..33cb6e6 100644
--- a/gdb/p-lang.c
+++ b/gdb/p-lang.c
@@ -230,7 +230,7 @@ pascal_printstr (struct ui_file *stream, struct type *type,
 		 const char *encoding, int force_ellipses,
 		 const struct value_print_options *options)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
+  enum bfd_endian byte_order = type_byte_order (type);
   unsigned int i;
   unsigned int things_printed = 0;
   int in_quotes = 0;
diff --git a/gdb/p-valprint.c b/gdb/p-valprint.c
index 10612f3..c465d14 100644
--- a/gdb/p-valprint.c
+++ b/gdb/p-valprint.c
@@ -67,7 +67,7 @@ pascal_val_print (struct type *type,
 		  const struct value_print_options *options)
 {
   struct gdbarch *gdbarch = get_type_arch (type);
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  enum bfd_endian byte_order = type_byte_order (type);
   unsigned int i = 0;	/* Number of characters printed */
   unsigned len;
   struct type *elttype;
diff --git a/gdb/printcmd.c b/gdb/printcmd.c
index 323a5d0..0251d46 100644
--- a/gdb/printcmd.c
+++ b/gdb/printcmd.c
@@ -356,7 +356,7 @@ print_scalar_formatted (const gdb_byte *valaddr, struct type *type,
 {
   struct gdbarch *gdbarch = get_type_arch (type);
   unsigned int len = TYPE_LENGTH (type);
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  enum bfd_endian byte_order = type_byte_order (type);
 
   /* String printing should go through val_print_scalar_formatted.  */
   gdb_assert (options->format != 's');
diff --git a/gdb/riscv-tdep.c b/gdb/riscv-tdep.c
index 810b834..d262b7d 100644
--- a/gdb/riscv-tdep.c
+++ b/gdb/riscv-tdep.c
@@ -688,7 +688,7 @@ riscv_print_one_register_info (struct gdbarch *gdbarch,
     {
       struct value_print_options opts;
       const gdb_byte *valaddr = value_contents_for_printing (val);
-      enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (regtype));
+      enum bfd_endian byte_order = type_byte_order (regtype);
 
       get_user_print_options (&opts);
       opts.deref_ref = 1;
diff --git a/gdb/solib-darwin.c b/gdb/solib-darwin.c
index 286e385..969bfd5 100644
--- a/gdb/solib-darwin.c
+++ b/gdb/solib-darwin.c
@@ -223,7 +223,7 @@ static struct so_list *
 darwin_current_sos (void)
 {
   struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
-  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
+  enum bfd_endian byte_order = type_byte_order (ptr_type);
   int ptr_len = TYPE_LENGTH (ptr_type);
   unsigned int image_info_size;
   struct so_list *head = NULL;
diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index 27299ff..de76557 100644
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -897,7 +897,7 @@ solib_svr4_r_ldsomap (struct svr4_info *info)
 {
   struct link_map_offsets *lmo = svr4_fetch_link_map_offsets ();
   struct type *ptr_type = builtin_type (target_gdbarch ())->builtin_data_ptr;
-  enum bfd_endian byte_order = gdbarch_byte_order (target_gdbarch ());
+  enum bfd_endian byte_order = type_byte_order (ptr_type);
   ULONGEST version = 0;
 
   try
diff --git a/gdb/stap-probe.c b/gdb/stap-probe.c
index ea206cb..ba92779 100644
--- a/gdb/stap-probe.c
+++ b/gdb/stap-probe.c
@@ -1435,8 +1435,8 @@ stap_modify_semaphore (CORE_ADDR address, int set, struct gdbarch *gdbarch)
       return;
     }
 
-  value = extract_unsigned_integer (bytes, TYPE_LENGTH (type),
-				    gdbarch_byte_order (gdbarch));
+  enum bfd_endian byte_order = type_byte_order (type);
+  value = extract_unsigned_integer (bytes, TYPE_LENGTH (type), byte_order);
   /* Note that we explicitly don't worry about overflow or
      underflow.  */
   if (set)
@@ -1444,8 +1444,7 @@ stap_modify_semaphore (CORE_ADDR address, int set, struct gdbarch *gdbarch)
   else
     --value;
 
-  store_unsigned_integer (bytes, TYPE_LENGTH (type),
-			  gdbarch_byte_order (gdbarch), value);
+  store_unsigned_integer (bytes, TYPE_LENGTH (type), byte_order, value);
 
   if (target_write_memory (address, bytes, TYPE_LENGTH (type)) != 0)
     warning (_("Could not write the value of a SystemTap semaphore."));
diff --git a/gdb/target-float.c b/gdb/target-float.c
index 4ef3505..caa6943 100644
--- a/gdb/target-float.c
+++ b/gdb/target-float.c
@@ -1753,7 +1753,7 @@ match_endianness (const gdb_byte *from, const struct type *type, gdb_byte *to)
 #define OPPOSITE_BYTE_ORDER BFD_ENDIAN_BIG
 #endif
 
-  if (gdbarch_byte_order (get_type_arch (type)) == OPPOSITE_BYTE_ORDER)
+  if (type_byte_order (type) == OPPOSITE_BYTE_ORDER)
     for (i = 0; i < len; i++)
       to[i] = from[len - i - 1];
   else
@@ -2160,8 +2160,8 @@ target_float_same_format_p (const struct type *type1,
 
       case TYPE_CODE_DECFLOAT:
 	return (TYPE_LENGTH (type1) == TYPE_LENGTH (type2)
-		&& (gdbarch_byte_order (get_type_arch (type1))
-		    == gdbarch_byte_order (get_type_arch (type2))));
+		&& (type_byte_order (type1)
+		    == type_byte_order (type2)));
 
       default:
 	gdb_assert_not_reached ("unexpected type code");
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 1685525..d4c42bd 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-11-21  Peeter Joot  <peeter.joot@lzlabs.com>
+
+	* gdb.base/endianity.c: New test.
+	* gdb.base/endianity.exp: New file.
+
 2019-11-21  Lukas Durfina  <ldurfina@tachyum.com>
 
 	* gdb.arch/amd64-eval.exp: Skip test if target is not x86-64.
diff --git a/gdb/testsuite/gdb.base/endianity.c b/gdb/testsuite/gdb.base/endianity.c
new file mode 100644
index 0000000..5ab090d
--- /dev/null
+++ b/gdb/testsuite/gdb.base/endianity.c
@@ -0,0 +1,45 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2019 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* This tests the handling of dwarf attributes:
+    DW_AT_endianity, DW_END_big, and DW_END_little.  */
+struct otherendian
+{
+  int v;
+  short w;
+}
+#if defined __GNUC__ && (__GNUC__ >= 6)
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+__attribute__( ( scalar_storage_order( "big-endian" ) ) )
+#else
+__attribute__( ( scalar_storage_order( "little-endian" ) ) )
+#endif
+#endif
+;
+
+void
+do_nothing (struct otherendian *c)
+{
+}
+
+int
+main (void)
+{
+  struct otherendian o = {3,2};
+
+  do_nothing (&o); /* START */
+}
diff --git a/gdb/testsuite/gdb.base/endianity.exp b/gdb/testsuite/gdb.base/endianity.exp
new file mode 100644
index 0000000..80df012
--- /dev/null
+++ b/gdb/testsuite/gdb.base/endianity.exp
@@ -0,0 +1,40 @@
+# Copyright 2019 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+standard_testfile .c
+
+if { [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] } {
+  return -1
+}
+
+set bp_location [gdb_get_line_number "START"]
+if ![runto "endianity.c:$bp_location" ] then {
+  fail "couldn't run to start"
+  return -1
+}
+
+gdb_test "print o" "= {v = 3, w = 2}" "print o before assignment"
+
+gdb_test "print o.v = 4" "= 4"
+gdb_test "print o.w = 3" "= 3"
+
+# scalar_storage_order requires gcc >= 6
+if { ([test_compiler_info {gcc-[0-5]-*}] || ![test_compiler_info gcc*]) } {
+  setup_xfail "*-*-*"
+}
+gdb_test "x/x &o.v" "0x04000000"
+gdb_test "x/xh &o.w" "0x0300"
+
+gdb_test "print o" "= {v = 4, w = 3}" "print o after assignment"
diff --git a/gdb/valarith.c b/gdb/valarith.c
index 7f1b24f..ea999b5 100644
--- a/gdb/valarith.c
+++ b/gdb/valarith.c
@@ -988,7 +988,7 @@ scalar_binop (struct value *arg1, struct value *arg2, enum exp_opcode op)
       val = allocate_value (result_type);
       store_signed_integer (value_contents_raw (val),
 			    TYPE_LENGTH (result_type),
-			    gdbarch_byte_order (get_type_arch (result_type)),
+			    type_byte_order (result_type),
 			    v);
     }
   else
@@ -1136,8 +1136,7 @@ scalar_binop (struct value *arg1, struct value *arg2, enum exp_opcode op)
 	  val = allocate_value (result_type);
 	  store_unsigned_integer (value_contents_raw (val),
 				  TYPE_LENGTH (value_type (val)),
-				  gdbarch_byte_order
-				    (get_type_arch (result_type)),
+				  type_byte_order (result_type),
 				  v);
 	}
       else
@@ -1266,8 +1265,7 @@ scalar_binop (struct value *arg1, struct value *arg2, enum exp_opcode op)
 	  val = allocate_value (result_type);
 	  store_signed_integer (value_contents_raw (val),
 				TYPE_LENGTH (value_type (val)),
-				gdbarch_byte_order
-				  (get_type_arch (result_type)),
+				type_byte_order (result_type),
 				v);
 	}
     }
@@ -1712,7 +1710,7 @@ value_bit_index (struct type *type, const gdb_byte *valaddr, int index)
     return -1;
   rel_index = index - low_bound;
   word = extract_unsigned_integer (valaddr + (rel_index / TARGET_CHAR_BIT), 1,
-				   gdbarch_byte_order (gdbarch));
+				   type_byte_order (type));
   rel_index %= TARGET_CHAR_BIT;
   if (gdbarch_bits_big_endian (gdbarch))
     rel_index = TARGET_CHAR_BIT - 1 - rel_index;
diff --git a/gdb/valops.c b/gdb/valops.c
index bfdd781..4597e99 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -483,7 +483,7 @@ value_cast (struct type *type, struct value *arg2)
       if (code2 == TYPE_CODE_PTR)
         longest = extract_unsigned_integer
 		    (value_contents (arg2), TYPE_LENGTH (type2),
-		     gdbarch_byte_order (get_type_arch (type2)));
+		     type_byte_order (type2));
       else
         longest = value_as_long (arg2);
       return value_from_longest (to_type, convert_to_boolean ?
diff --git a/gdb/valprint.c b/gdb/valprint.c
index e0eb8e1..ced0dbc 100644
--- a/gdb/valprint.c
+++ b/gdb/valprint.c
@@ -2402,7 +2402,7 @@ generic_emit_char (int c, struct type *type, struct ui_file *stream,
 		   int quoter, const char *encoding)
 {
   enum bfd_endian byte_order
-    = gdbarch_byte_order (get_type_arch (type));
+    = type_byte_order (type);
   gdb_byte *c_buf;
   int need_escape = 0;
 
@@ -2722,7 +2722,7 @@ generic_printstr (struct ui_file *stream, struct type *type,
 		  int quote_char, int c_style_terminator,
 		  const struct value_print_options *options)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
+  enum bfd_endian byte_order = type_byte_order (type);
   unsigned int i;
   int width = TYPE_LENGTH (type);
   int finished = 0;
@@ -2834,7 +2834,7 @@ val_print_string (struct type *elttype, const char *encoding,
   int bytes_read;
   gdb::unique_xmalloc_ptr<gdb_byte> buffer;	/* Dynamically growable fetch buffer.  */
   struct gdbarch *gdbarch = get_type_arch (elttype);
-  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  enum bfd_endian byte_order = type_byte_order (elttype);
   int width = TYPE_LENGTH (elttype);
 
   /* First we need to figure out the limit on the number of characters we are
diff --git a/gdb/value.c b/gdb/value.c
index 47e647a..35a7a5c 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -2737,7 +2737,7 @@ value_as_address (struct value *val)
 LONGEST
 unpack_long (struct type *type, const gdb_byte *valaddr)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
+  enum bfd_endian byte_order = type_byte_order (type);
   enum type_code code = TYPE_CODE (type);
   int len = TYPE_LENGTH (type);
   int nosign = TYPE_UNSIGNED (type);
@@ -3100,7 +3100,7 @@ static LONGEST
 unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr,
 		     LONGEST bitpos, LONGEST bitsize)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (field_type));
+  enum bfd_endian byte_order = type_byte_order (field_type);
   ULONGEST val;
   ULONGEST valmask;
   int lsbcount;
@@ -3209,7 +3209,7 @@ unpack_value_bitfield (struct value *dest_val,
   int dst_bit_offset;
   struct type *field_type = value_type (dest_val);
 
-  byte_order = gdbarch_byte_order (get_type_arch (field_type));
+  byte_order = type_byte_order (field_type);
 
   /* First, unpack and sign extend the bitfield as if it was wholly
      valid.  Optimized out/unavailable bits are read as zero, but
@@ -3269,7 +3269,7 @@ void
 modify_field (struct type *type, gdb_byte *addr,
 	      LONGEST fieldval, LONGEST bitpos, LONGEST bitsize)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
+  enum bfd_endian byte_order = type_byte_order (type);
   ULONGEST oword;
   ULONGEST mask = (ULONGEST) -1 >> (8 * sizeof (ULONGEST) - bitsize);
   LONGEST bytesize;
@@ -3315,7 +3315,7 @@ modify_field (struct type *type, gdb_byte *addr,
 void
 pack_long (gdb_byte *buf, struct type *type, LONGEST num)
 {
-  enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
+  enum bfd_endian byte_order = type_byte_order (type);
   LONGEST len;
 
   type = check_typedef (type);
@@ -3363,7 +3363,7 @@ pack_unsigned_long (gdb_byte *buf, struct type *type, ULONGEST num)
 
   type = check_typedef (type);
   len = TYPE_LENGTH (type);
-  byte_order = gdbarch_byte_order (get_type_arch (type));
+  byte_order = type_byte_order (type);
 
   switch (TYPE_CODE (type))
     {