MIPS: ported r9119 fixing performance regression in regexp.

src/mips/code-stubs-mips.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4651 matching lines @@
 
   // For arguments 4 and 3 get string length, calculate start of string data
   // and calculate the shift of the index (0 for ASCII and 1 for two byte).
   STATIC_ASSERT(SeqAsciiString::kHeaderSize == SeqTwoByteString::kHeaderSize);
   __ Addu(t2, subject, Operand(SeqAsciiString::kHeaderSize - kHeapObjectTag));
   __ Xor(a3, a3, Operand(1));  // 1 for 2-byte str, 0 for 1-byte.
   // Load the length from the original subject string from the previous stack
   // frame. Therefore we have to use fp, which points exactly to two pointer
   // sizes below the previous sp. (Because creating a new stack frame pushes
   // the previous fp onto the stack and moves up sp by 2 * kPointerSize.)
-  __ lw(a0, MemOperand(fp, kSubjectOffset + 2 * kPointerSize));
+  __ lw(subject, MemOperand(fp, kSubjectOffset + 2 * kPointerSize));
   // If slice offset is not 0, load the length from the original sliced string.
   // Argument 4, a3: End of string data
   // Argument 3, a2: Start of string data
   // Prepare start and end index of the input.
   __ sllv(t1, t0, a3);
   __ addu(t0, t2, t1);
   __ sllv(t1, a1, a3);
   __ addu(a2, t0, t1);
 
-  __ lw(t2, FieldMemOperand(a0, String::kLengthOffset));
+  __ lw(t2, FieldMemOperand(subject, String::kLengthOffset));
   __ sra(t2, t2, kSmiTagSize);
   __ sllv(t1, t2, a3);
   __ addu(a3, t0, t1);
   // Argument 2 (a1): Previous index.
   // Already there
 
   // Argument 1 (a0): Subject string.
-  // Already there
+  __ mov(a0, subject);
 
   // Locate the code entry and call it.
   __ Addu(t9, t9, Operand(Code::kHeaderSize - kHeapObjectTag));
   DirectCEntryStub stub;
   stub.GenerateCall(masm, t9);
 
   __ LeaveExitFrame(false, no_reg);
 
   // v0: result
   // subject: subject string (callee saved)
   // regexp_data: RegExp data (callee saved)
   // last_match_info_elements: Last match info elements (callee saved)
 
   // Check the result.
 
   Label success;
   __ Branch(&success, eq,
-            subject, Operand(NativeRegExpMacroAssembler::SUCCESS));
+            v0, Operand(NativeRegExpMacroAssembler::SUCCESS));
   Label failure;
   __ Branch(&failure, eq,
-            subject, Operand(NativeRegExpMacroAssembler::FAILURE));
+            v0, Operand(NativeRegExpMacroAssembler::FAILURE));
   // If not exception it can only be retry. Handle that in the runtime system.
   __ Branch(&runtime, ne,
-            subject, Operand(NativeRegExpMacroAssembler::EXCEPTION));
+            v0, Operand(NativeRegExpMacroAssembler::EXCEPTION));
   // Result must now be exception. If there is no pending exception already a
   // stack overflow (on the backtrack stack) was detected in RegExp code but
   // haven't created the exception yet. Handle that in the runtime system.
   // TODO(592): Rerunning the RegExp to get the stack overflow exception.
   __ li(a1, Operand(
       ExternalReference::the_hole_value_location(masm->isolate())));
   __ lw(a1, MemOperand(a1, 0));
   __ li(a2, Operand(ExternalReference(Isolate::k_pending_exception_address,
                                       masm->isolate())));
   __ lw(v0, MemOperand(a2, 0));
-  __ Branch(&runtime, eq, subject, Operand(a1));
+  __ Branch(&runtime, eq, v0, Operand(a1));
 
   __ sw(a1, MemOperand(a2, 0));  // Clear pending exception.
 
   // Check if the exception is a termination. If so, throw as uncatchable.
   __ LoadRoot(a0, Heap::kTerminationExceptionRootIndex);
   Label termination_exception;
-  __ Branch(&termination_exception, eq, subject, Operand(a0));
+  __ Branch(&termination_exception, eq, v0, Operand(a0));
 
-  __ Throw(subject);  // Expects thrown value in v0.
+  __ Throw(v0);  // Expects thrown value in v0.
 
   __ bind(&termination_exception);
   __ ThrowUncatchable(TERMINATION, v0);  // Expects thrown value in v0.
 
   __ bind(&failure);
   // For failure and exception return null.
   __ li(v0, Operand(masm->isolate()->factory()->null_value()));
   __ Addu(sp, sp, Operand(4 * kPointerSize));
   __ Ret();
 
@@ skipping 2141 matching lines @@
   __ mov(result, zero_reg);
   __ Ret();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS