Implement the Oilpan pushAllRegisters on MIPS64

Source/platform/heap/asm/SaveRegisters_mips64.S

Index: Source/platform/heap/asm/SaveRegisters_mips64.S
diff --git a/Source/platform/heap/asm/SaveRegisters_mips64.S b/Source/platform/heap/asm/SaveRegisters_mips64.S
new file mode 100644
index 0000000000000000000000000000000000000000..3c9b02ee4c0a7f47373130081e5774ef3cfa20c1
--- /dev/null
+++ b/Source/platform/heap/asm/SaveRegisters_mips64.S
@@ -0,0 +1,41 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/*
+ * typedef void (*PushAllRegistersCallback)(SafePointBarrier*, ThreadState*, intptr_t*);
+ * extern "C" void pushAllRegisters(SafePointBarrier*, ThreadState*, PushAllRegistersCallback)
+ */
+
+.type pushAllRegisters, %function
+.global pushAllRegisters
+.hidden pushAllRegisters
+pushAllRegisters:
+        // Push all callee-saves registers to get them
+        // on the stack for conservative stack scanning.
+        // Reserve space for callee-saved registers and return address.
+        daddiu $sp,$sp,-80
+        // Save the callee-saved registers and the return address.
+        sd $s0,0($sp)
+        sd $s1,8($sp)
+        sd $s2,16($sp)
+        sd $s3,24($sp)
+        sd $s4,32($sp)
+        sd $s5,40($sp)
+        sd $s6,48($sp)
+        sd $s7,56($sp)
+        sd $ra,64($sp)
+        // Note: the callee-saved floating point registers do not need to be
+        // copied to the stack, because fp registers never hold heap pointers
+        // and so do not need to be kept visible to the garbage collector.
+        // Pass the two first arguments untouched in a0 and a1 and the
+        // stack pointer to the callback.
+        move $t9,$a2
+        move $a2,$sp
+        jal $t9
+        // Restore return address, adjust stack and return.
+        // Note: the copied registers do not need to be reloaded here,
+        // because they were preserved by the called routine.
+        ld $ra,64($sp)
+        daddiu $sp,$sp,80
+        jr $ra