MIPS: Fix int64->int32 lowering in wasm-to-interpeter entry on big-endian archs.

src/utils.h

Index: src/utils.h
diff --git a/src/utils.h b/src/utils.h
index acc06d3afaaddffc4e55fbdf902b956a9cdaf541..2b4b2b5e9e2da7122da53009c4d9010b036ea614 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -520,6 +520,16 @@ const int kMinComplexMemCopy = 8;
 // ----------------------------------------------------------------------------
 // Miscellaneous
 
+// Memory offset for Lower and Higher bits in a

[Clemens Hammacher, 2017/03/01 08:51:13]

It looks like this comment could fit in one line. Also, please fix the
capitalization of "Lower" and "Higher" and add a "." at the end.

[ivica.bogosavljevic, 2017/03/01 12:58:48]

Acknowledged.

+// 64 bit integer
+#if defined(V8_TARGET_LITTLE_ENDIAN)

[Clemens Hammacher, 2017/03/01 08:51:13]

Please move these definitions to wasm-compiler.cc.

[ivica.bogosavljevic, 2017/03/01 12:58:48]

I added this definition on purpose in the header and not in wasm-compiler.cc.
There are same constants albeit with the different name defined elsewhere e.g.
int64-lowering.cc:123, objects.h:1820, assembler-mips.h:115. I plan to upload
another patch that cleans this up.

[Clemens Hammacher, 2017/03/01 13:15:20]

Agreed, that sounds reasonable. Looking forward to this cleanup.
Could you pick a more descriptive name anyway? "HigherBits" and "LowerBits"
sounds too generic for me (which bits?). What about "UpperHalf" and "LowerHalf"?

[ivica.bogosavljevic, 2017/03/01 15:35:32]

Acknowledged.

+static const int kInt64LowerBitsMememoryOffset = 0;

[Clemens Hammacher, 2017/03/01 08:51:13]

Typo "Mememory"

[ivica.bogosavljevic, 2017/03/01 12:58:48]

Acknowledged.

+static const int kInt64HigherBitsMemoryOffset = 4;
+#elif defined(V8_TARGET_BIG_ENDIAN)
+static const int kInt64LowerBitsMememoryOffset = 4;
+static const int kInt64HigherBitsMemoryOffset = 0;
+#endif  // V8_TARGET_LITTLE_ENDIAN
+
 // A static resource holds a static instance that can be reserved in
 // a local scope using an instance of Access.  Attempts to re-reserve
 // the instance will cause an error.