[regexp] Turn last match info into a simple FixedArray

src/mips/code-stubs-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_MIPS
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 1607 matching lines @@
   // Process the result from the native regexp code.
   __ bind(&success);
   __ lw(a1,
          FieldMemOperand(regexp_data, JSRegExp::kIrregexpCaptureCountOffset));
   // Calculate number of capture registers (number_of_captures + 1) * 2.
   // Multiplying by 2 comes for free since r1 is smi-tagged.
   STATIC_ASSERT(kSmiTag == 0);
   STATIC_ASSERT(kSmiTagSize + kSmiShiftSize == 1);
   __ Addu(a1, a1, Operand(2));  // a1 was a smi.
 
-  __ lw(a0, MemOperand(sp, kLastMatchInfoOffset));
-  __ JumpIfSmi(a0, &runtime);
-  __ GetObjectType(a0, a2, a2);
-  __ Branch(&runtime, ne, a2, Operand(JS_OBJECT_TYPE));
+  // Check that the last match info is a FixedArray.
+  __ lw(last_match_info_elements, MemOperand(sp, kLastMatchInfoOffset));
+  __ JumpIfSmi(last_match_info_elements, &runtime);
   // Check that the object has fast elements.
-  __ lw(last_match_info_elements,
-        FieldMemOperand(a0, JSArray::kElementsOffset));
   __ lw(a0, FieldMemOperand(last_match_info_elements, HeapObject::kMapOffset));
   __ LoadRoot(at, Heap::kFixedArrayMapRootIndex);
   __ Branch(&runtime, ne, a0, Operand(at));
   // Check that the last match info has space for the capture registers and the
   // additional information.
   __ lw(a0,
         FieldMemOperand(last_match_info_elements, FixedArray::kLengthOffset));
-  __ Addu(a2, a1, Operand(RegExpImpl::kLastMatchOverhead));
+  __ Addu(a2, a1, Operand(RegExpMatchInfo::kLastMatchOverhead));
   __ sra(at, a0, kSmiTagSize);
   __ Branch(&runtime, gt, a2, Operand(at));
 
   // a1: number of capture registers
   // subject: subject string
   // Store the capture count.
   __ sll(a2, a1, kSmiTagSize + kSmiShiftSize);  // To smi.
   __ sw(a2, FieldMemOperand(last_match_info_elements,
-                             RegExpImpl::kLastCaptureCountOffset));
+                            RegExpMatchInfo::kNumberOfCapturesOffset));
   // Store last subject and last input.
-  __ sw(subject,
-         FieldMemOperand(last_match_info_elements,
-                         RegExpImpl::kLastSubjectOffset));
+  __ sw(subject, FieldMemOperand(last_match_info_elements,
+                                 RegExpMatchInfo::kLastSubjectOffset));
   __ mov(a2, subject);
   __ RecordWriteField(last_match_info_elements,
-                      RegExpImpl::kLastSubjectOffset,
-                      subject,
-                      t3,
-                      kRAHasNotBeenSaved,
-                      kDontSaveFPRegs);
+                      RegExpMatchInfo::kLastSubjectOffset, subject, t3,
+                      kRAHasNotBeenSaved, kDontSaveFPRegs);
   __ mov(subject, a2);
-  __ sw(subject,
-         FieldMemOperand(last_match_info_elements,
-                         RegExpImpl::kLastInputOffset));
+  __ sw(subject, FieldMemOperand(last_match_info_elements,
+                                 RegExpMatchInfo::kLastInputOffset));
   __ RecordWriteField(last_match_info_elements,
-                      RegExpImpl::kLastInputOffset,
-                      subject,
-                      t3,
-                      kRAHasNotBeenSaved,
-                      kDontSaveFPRegs);
+                      RegExpMatchInfo::kLastInputOffset, subject, t3,
+                      kRAHasNotBeenSaved, kDontSaveFPRegs);
 
   // Get the static offsets vector filled by the native regexp code.
   ExternalReference address_of_static_offsets_vector =
       ExternalReference::address_of_static_offsets_vector(isolate());
   __ li(a2, Operand(address_of_static_offsets_vector));
 
   // a1: number of capture registers
   // a2: offsets vector
   Label next_capture, done;
   // Capture register counter starts from number of capture registers and
   // counts down until wrapping after zero.
-  __ Addu(a0,
-         last_match_info_elements,
-         Operand(RegExpImpl::kFirstCaptureOffset - kHeapObjectTag));
+  __ Addu(a0, last_match_info_elements,
+          Operand(RegExpMatchInfo::kFirstCaptureOffset - kHeapObjectTag));
   __ bind(&next_capture);
   __ Subu(a1, a1, Operand(1));
   __ Branch(&done, lt, a1, Operand(zero_reg));
   // Read the value from the static offsets vector buffer.
   __ lw(a3, MemOperand(a2, 0));
   __ addiu(a2, a2, kPointerSize);
   // Store the smi value in the last match info.
   __ sll(a3, a3, kSmiTagSize);  // Convert to Smi.
   __ sw(a3, MemOperand(a0, 0));
   __ Branch(&next_capture, USE_DELAY_SLOT);
   __ addiu(a0, a0, kPointerSize);  // In branch delay slot.
 
   __ bind(&done);
 
   // Return last match info.
-  __ lw(v0, MemOperand(sp, kLastMatchInfoOffset));
+  __ mov(v0, last_match_info_elements);
   __ DropAndRet(4);
 
   // Do the runtime call to execute the regexp.
   __ bind(&runtime);
   __ TailCallRuntime(Runtime::kRegExpExec);
 
   // Deferred code for string handling.
   // (5) Long external string?  If not, go to (7).
   __ bind(&not_seq_nor_cons);
   // Go to (7).
@@ skipping 3142 matching lines @@
                            kStackUnwindSpace, kInvalidStackOffset,
                            return_value_operand, NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS