MIPS: port Link function contexts directly to the previous context.

Ported r8238 (7803ed7)

This commit would have also included changes to macro-assembler-mips.cc,
however Kevin M. did those changes in later commit r8248. (thx!)

BUG=
TEST=

Committed: http://code.google.com/p/v8/source/detail?r=8249

Review URL: http://codereview.chromium.org//6995128
Patch from Paul Lind <plind44@gmail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8250 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/code-stubs-mips.cc

@@ -167,10 +167,10 @@ void FastNewContextStub::Generate(MacroAssembler* masm) {
   __ li(a1, Operand(Smi::FromInt(0)));
   __ sw(a3, MemOperand(v0, Context::SlotOffset(Context::CLOSURE_INDEX)));
   __ sw(v0, MemOperand(v0, Context::SlotOffset(Context::FCONTEXT_INDEX)));
-  __ sw(a1, MemOperand(v0, Context::SlotOffset(Context::PREVIOUS_INDEX)));
+  __ sw(cp, MemOperand(v0, Context::SlotOffset(Context::PREVIOUS_INDEX)));
   __ sw(a1, MemOperand(v0, Context::SlotOffset(Context::EXTENSION_INDEX)));
 
-  // Copy the global object from the surrounding context.
+  // Copy the global object from the previous context.
   __ lw(a1, MemOperand(cp, Context::SlotOffset(Context::GLOBAL_INDEX)));
   __ sw(a1, MemOperand(v0, Context::SlotOffset(Context::GLOBAL_INDEX)));