MIPS: Add external strings support to regexp in generated code.

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 4729 matching lines @@
 
   // Reset offset for possibly sliced string.
   __ mov(t0, zero_reg);
   // subject: Subject string
   // regexp_data: RegExp data (FixedArray)
   // Check the representation and encoding of the subject string.
   Label seq_string;
   __ lw(a0, FieldMemOperand(subject, HeapObject::kMapOffset));
   __ lbu(a0, FieldMemOperand(a0, Map::kInstanceTypeOffset));
   // First check for flat string.  None of the following string type tests will
-  // succeed if kIsNotStringTag is set.
-  __ And(a1, a0, Operand(kIsNotStringMask | kStringRepresentationMask));
+  // succeed if subject is not a string or a short external string.
+  __ And(a1,
+         a0,
+         Operand(kIsNotStringMask |
+                 kStringRepresentationMask |
+                 kShortExternalStringMask));
   STATIC_ASSERT((kStringTag | kSeqStringTag) == 0);
   __ Branch(&seq_string, eq, a1, Operand(zero_reg));
 
   // subject: Subject string
   // a0: instance type if Subject string
   // regexp_data: RegExp data (FixedArray)
   // a1: whether subject is a string and if yes, its string representation
   // Check for flat cons string or sliced string.
   // A flat cons string is a cons string where the second part is the empty
   // string. In that case the subject string is just the first part of the cons
   // string. Also in this case the first part of the cons string is known to be
   // a sequential string or an external string.
   // In the case of a sliced string its offset has to be taken into account.
-  Label cons_string, check_encoding;
+  Label cons_string, external_string, check_encoding;
   STATIC_ASSERT(kConsStringTag < kExternalStringTag);
   STATIC_ASSERT(kSlicedStringTag > kExternalStringTag);
   STATIC_ASSERT(kIsNotStringMask > kExternalStringTag);
+  STATIC_ASSERT(kShortExternalStringTag > kExternalStringTag);
   __ Branch(&cons_string, lt, a1, Operand(kExternalStringTag));
-  __ Branch(&runtime, eq, a1, Operand(kExternalStringTag));
+  __ Branch(&external_string, eq, a1, Operand(kExternalStringTag));
 
-  // Catch non-string subject (should already have been guarded against).
-  STATIC_ASSERT(kNotStringTag != 0);
-  __ And(at, a1, Operand(kIsNotStringMask));
+  // Catch non-string subject or short external string.
+  STATIC_ASSERT(kNotStringTag != 0 && kShortExternalStringTag !=0);
+  __ And(at, a1, Operand(kIsNotStringMask | kShortExternalStringMask));
   __ Branch(&runtime, ne, at, Operand(zero_reg));
 
   // String is sliced.
   __ lw(t0, FieldMemOperand(subject, SlicedString::kOffsetOffset));
   __ sra(t0, t0, kSmiTagSize);
   __ lw(subject, FieldMemOperand(subject, SlicedString::kParentOffset));
   // t5: offset of sliced string, smi-tagged.
   __ jmp(&check_encoding);
   // String is a cons string, check whether it is flat.
   __ bind(&cons_string);
   __ lw(a0, FieldMemOperand(subject, ConsString::kSecondOffset));
   __ LoadRoot(a1, Heap::kEmptyStringRootIndex);
   __ Branch(&runtime, ne, a0, Operand(a1));
   __ lw(subject, FieldMemOperand(subject, ConsString::kFirstOffset));
   // Is first part of cons or parent of slice a flat string?
   __ bind(&check_encoding);
   __ lw(a0, FieldMemOperand(subject, HeapObject::kMapOffset));
   __ lbu(a0, FieldMemOperand(a0, Map::kInstanceTypeOffset));
   STATIC_ASSERT(kSeqStringTag == 0);
   __ And(at, a0, Operand(kStringRepresentationMask));
-  __ Branch(&runtime, ne, at, Operand(zero_reg));
+  __ Branch(&external_string, ne, at, Operand(zero_reg));
 
   __ bind(&seq_string);
   // subject: Subject string
   // regexp_data: RegExp data (FixedArray)
   // a0: Instance type of subject string
   STATIC_ASSERT(kStringEncodingMask == 4);
   STATIC_ASSERT(kAsciiStringTag == 4);
   STATIC_ASSERT(kTwoByteStringTag == 0);
   // Find the code object based on the assumptions above.
   __ And(a0, a0, Operand(kStringEncodingMask));  // Non-zero for ascii.
@@ skipping 205 matching lines @@
   __ 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));
   __ Addu(sp, sp, Operand(4 * kPointerSize));
   __ Ret();
 
+  // External string.  Short external strings have already been ruled out.
+  // a0: scratch
+  __ bind(&external_string);
+  __ lw(a0, FieldMemOperand(subject, HeapObject::kMapOffset));
+  __ lbu(a0, FieldMemOperand(a0, Map::kInstanceTypeOffset));
+  if (FLAG_debug_code) {
+    // Assert that we do not have a cons or slice (indirect strings) here.
+    // Sequential strings have already been ruled out.
+    __ And(at, a0, Operand(kIsIndirectStringMask));
+    __ Assert(eq, "external string expected, but not found",
+        at, Operand(zero_reg));
+  }
+  __ lw(subject,
+        FieldMemOperand(subject, ExternalString::kResourceDataOffset));
+  // Move the pointer so that offset-wise, it looks like a sequential string.
+  STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqAsciiString::kHeaderSize);
+  __ Subu(subject,
+          subject,
+          SeqTwoByteString::kHeaderSize - kHeapObjectTag);
+  __ jmp(&seq_string);
+
   // Do the runtime call to execute the regexp.
   __ bind(&runtime);
   __ TailCallRuntime(Runtime::kRegExpExec, 4, 1);
 #endif  // V8_INTERPRETED_REGEXP
 }
 
 
 void RegExpConstructResultStub::Generate(MacroAssembler* masm) {
   const int kMaxInlineLength = 100;
   Label slowcase;
@@ skipping 2438 matching lines @@
                                  &slow_elements);
   __ Ret();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS