A little peephole optimization for the Irregexp bytecode interpreter.

Review URL: http://codereview.chromium.org/21481

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1311 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/bytecodes-irregexp.h

-// Copyright 2008 the V8 project authors. All rights reserved.
+// Copyright 2008-2009 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:
@@ -86,7 +86,8 @@ V(CHECK_REGISTER_GE, 42, 12)  /* bc8 reg_idx24 value32 addr32               */ \
 V(CHECK_REGISTER_EQ_POS, 43, 8) /* bc8 reg_idx24 addr32                     */ \
 V(CHECK_AT_START,    44, 8)   /* bc8 pad24 addr32                           */ \
 V(CHECK_NOT_AT_START, 45, 8)  /* bc8 pad24 addr32                           */ \
-V(CHECK_GREEDY,      46, 8)   /* bc8 pad24 addr32                           */
+V(CHECK_GREEDY,      46, 8)   /* bc8 pad24 addr32                           */ \
+V(ADVANCE_CP_AND_GOTO, 47, 8) /* bc8 offset24 addr32                        */
 
 #define DECLARE_BYTECODES(name, code, length) \
   static const int BC_##name = code;

src/interpreter-irregexp.cc

@@ -238,6 +238,10 @@ static bool RawMatch(const byte* code_base,
       BYTECODE(GOTO)
         pc = code_base + Load32Aligned(pc + 4);
         break;
+      BYTECODE(ADVANCE_CP_AND_GOTO)
+        current += insn >> BYTECODE_SHIFT;
+        pc = code_base + Load32Aligned(pc + 4);
+        break;
       BYTECODE(CHECK_GREEDY)
         if (current == backtrack_sp[-1]) {
           backtrack_sp--;

src/jsregexp.cc

-// Copyright 2006-2008 the V8 project authors. All rights reserved.
+// Copyright 2006-2009 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:

src/regexp-macro-assembler-irregexp-inl.h

-// Copyright 2008 the V8 project authors. All rights reserved.
+// Copyright 2008-2009 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:

src/regexp-macro-assembler-irregexp.cc

-// Copyright 2008 the V8 project authors. All rights reserved.
+// Copyright 2008-2009 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:
@@ -39,7 +39,8 @@ namespace v8 { namespace internal {
 RegExpMacroAssemblerIrregexp::RegExpMacroAssemblerIrregexp(Vector<byte> buffer)
     : buffer_(buffer),
       pc_(0),
-      own_buffer_(false) {
+      own_buffer_(false),
+      advance_current_end_(kInvalidPC) {
 }
 
 
@@ -55,6 +56,7 @@ RegExpMacroAssemblerIrregexp::Implementation() {
 
 
 void RegExpMacroAssemblerIrregexp::Bind(Label* l) {
+  advance_current_end_ = kInvalidPC;
   ASSERT(!l->is_bound());
   if (l->is_linked()) {
     int pos = l->pos();
@@ -172,8 +174,17 @@ void RegExpMacroAssemblerIrregexp::Backtrack() {
 
 
 void RegExpMacroAssemblerIrregexp::GoTo(Label* l) {
-  Emit(BC_GOTO, 0);
-  EmitOrLink(l);
+  if (advance_current_end_ == pc_) {
+    // Combine advance current and goto.
+    pc_ = advance_current_start_;
+    Emit(BC_ADVANCE_CP_AND_GOTO, advance_current_offset_);
+    EmitOrLink(l);
+    advance_current_end_ = kInvalidPC;
+  } else {
+    // Regular goto.
+    Emit(BC_GOTO, 0);
+    EmitOrLink(l);
+  }
 }
 
 
@@ -196,7 +207,10 @@ void RegExpMacroAssemblerIrregexp::Fail() {
 void RegExpMacroAssemblerIrregexp::AdvanceCurrentPosition(int by) {
   ASSERT(by >= kMinCPOffset);
   ASSERT(by <= kMaxCPOffset);
+  advance_current_start_ = pc_;
+  advance_current_offset_ = by;
   Emit(BC_ADVANCE_CP, by);
+  advance_current_end_ = pc_;
 }
 
 

src/regexp-macro-assembler-irregexp.h

-// Copyright 2008 the V8 project authors. All rights reserved.
+// Copyright 2008-2009 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:
@@ -133,6 +133,12 @@ class RegExpMacroAssemblerIrregexp: public RegExpMacroAssembler {
   bool own_buffer_;
   Label backtrack_;
 
+  int advance_current_start_;
+  int advance_current_offset_;
+  int advance_current_end_;
+
+  static const int kInvalidPC = -1;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(RegExpMacroAssemblerIrregexp);
 };