MIPS64: Add big-endian support for mips64.

build/toolchain.gypi

Index: build/toolchain.gypi
diff --git a/build/toolchain.gypi b/build/toolchain.gypi
index 2163171d7e55a01f6d79beaa489a87f7f0175a58..a0767ea6ed8d586b32dad6b9a00c2f4f7d57e3ae 100644
--- a/build/toolchain.gypi
+++ b/build/toolchain.gypi
@@ -743,7 +743,7 @@
           }],
         ],
       }],  # v8_target_arch=="mipsel"
-      ['v8_target_arch=="mips64el"', {
+      ['v8_target_arch=="mips64el" or v8_target_arch=="mips64"', {
         'defines': [
           'V8_TARGET_ARCH_MIPS64',
         ],
@@ -753,6 +753,16 @@
               'CAN_USE_FPU_INSTRUCTIONS',
             ],
           }],
+          [ 'v8_host_byteorder=="little"', {
+            'defines': [
+              'V8_TARGET_ARCH_MIPS64_LE',

[paul.l..., 2015/09/15 00:06:41]

Per MIPS conventions, this should probably be called V8_TARGET_ARCH_MIPS64_EL.

Also, this defintion does not appear to be used, so maybe unnecessary?

[dusan.milosavljevic, 2015/09/15 12:58:09]

Not based on MIPS convention, I used these names to be consistent with other
ports (ppc).

+            ],
+          }],
+          [ 'v8_host_byteorder=="big"', {
+            'defines': [
+              'V8_TARGET_ARCH_MIPS64_BE',

[paul.l..., 2015/09/15 00:06:41]

Should be  ..._EB, as above. While you use this in build_config.h, I don't
understand the reason why. Maybe you can elaborate on the comment in that file.

[dusan.milosavljevic, 2015/09/15 12:58:09]

This is used to detect host byte-order in addition to detection of target
toolchain flags. This enables correct build on be hosts.

+            ],
+          }],
           [ 'v8_use_mips_abi_hardfloat=="true"', {
             'defines': [
               '__mips_hard_float=1',
@@ -769,11 +779,17 @@
             'conditions': [
               ['v8_target_arch==target_arch', {
                 'cflags': [
-                  '-EL',
                   '-Wno-error=array-bounds',  # Workaround https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56273
                 ],
-                'ldflags': ['-EL'],
                 'conditions': [
+                  ['v8_target_arch=="mips64el"', {
+                    'cflags': ['-EL'],
+                    'ldflags': ['-EL'],
+                  }],
+                  ['v8_target_arch=="mips64"', {
+                    'cflags': ['-EB'],
+                    'ldflags': ['-EB'],
+                  }],
                   [ 'v8_use_mips_abi_hardfloat=="true"', {
                     'cflags': ['-mhard-float'],
                     'ldflags': ['-mhard-float'],