Add external strings support to regexp in generated code.

src/ia32/code-stubs-ia32.cc

Index: src/ia32/code-stubs-ia32.cc
diff --git a/src/ia32/code-stubs-ia32.cc b/src/ia32/code-stubs-ia32.cc
index c6c1009c8cf7d28e2d8bf6ea12259783b5424a64..309e3e0f1eeae73f93c0fafd67bc7782c37d27d7 100644
--- a/src/ia32/code-stubs-ia32.cc
+++ b/src/ia32/code-stubs-ia32.cc
@@ -3613,12 +3613,12 @@ void RegExpExecStub::Generate(MacroAssembler* masm) {
   // 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);
   __ cmp(ebx, Immediate(kExternalStringTag));
   __ j(less, &cons_string);
-  __ j(equal, &runtime);
+  __ j(equal, &external_string);
 
   // String is sliced.
   __ mov(edi, FieldOperand(eax, SlicedString::kOffsetOffset));
@@ -3640,10 +3640,10 @@ void RegExpExecStub::Generate(MacroAssembler* masm) {
             kStringRepresentationMask | kStringEncodingMask);
   STATIC_ASSERT((kSeqStringTag | kTwoByteStringTag) == 0);
   __ j(zero, &seq_two_byte_string, Label::kNear);
-  // Any other flat string must be ascii.
+  // Any other flat string must be sequential ascii or external.
   __ test_b(FieldOperand(ebx, Map::kInstanceTypeOffset),
             kStringRepresentationMask);
-  __ j(not_zero, &runtime);
+  __ j(not_zero, &external_string);
 
   __ bind(&seq_ascii_string);
   // eax: subject string (flat ascii)
@@ -3864,6 +3864,31 @@ void RegExpExecStub::Generate(MacroAssembler* masm) {
   __ mov(eax, Operand(esp, kLastMatchInfoOffset));
   __ ret(4 * kPointerSize);
 
+  // String is external.
+  // eax: subject string (expected to be external)
+  // ebx: scratch
+  __ bind(&external_string);
+  __ mov(ebx, FieldOperand(eax, HeapObject::kMapOffset));
+  __ movzx_b(ebx, FieldOperand(ebx, 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.
+    __ test_b(ebx, kIsIndirectStringMask);
+    __ Assert(zero, "external string expected, but not found");
+  }
+  // Rule out short external strings.
+  STATIC_CHECK(kShortExternalStringTag != 0);
+  __ test_b(ebx, kShortExternalStringMask);
+  __ j(not_zero, &runtime);
+  __ mov(eax, FieldOperand(eax, ExternalString::kResourceDataOffset));
+  // Move the pointer so that offset-wise, it looks like a sequential string.
+  STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqAsciiString::kHeaderSize);
+  __ sub(eax, Immediate(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
+  STATIC_ASSERT(kTwoByteStringTag == 0);
+  __ test_b(ebx, kStringEncodingMask);
+  __ j(not_zero, &seq_ascii_string);
+  __ jmp(&seq_two_byte_string);
+
   // Do the runtime call to execute the regexp.
   __ bind(&runtime);
   __ TailCallRuntime(Runtime::kRegExpExec, 4, 1);