Recognize standard character classes and implement more efficient matchers.

src/regexp-macro-assembler-ia32.cc

 // Copyright 2008 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 388 matching lines @@
     uc16 minus,
     uc16 mask,
     Label* on_not_equal) {
   ASSERT(minus < String::kMaxUC16CharCode);
   __ lea(eax, Operand(current_character(), -minus));
   __ and_(eax, mask);
   __ cmp(eax, c);
   BranchOrBacktrack(not_equal, on_not_equal);
 }
 
+bool RegExpMacroAssemblerIA32::CheckSpecialCharacterClass(uc16 type,

[Mads Ager (chromium), 2009/01/02 10:51:06]

A lot of unnamed constants are used in this code and it is not obvious to me
what is going on.  I think each of the cases in the switch should have a comment
explaining what is going on.

+                                                          int cp_offset,
+                                                          bool check_offset,
+                                                          Label* on_no_match) {
+  switch (type) {
+  case 's':
+    if (mode_ == ASCII) {
+      if (check_offset) {
+        LoadCurrentCharacter(cp_offset, on_no_match);
+      } else {
+        LoadCurrentCharacterUnchecked(cp_offset, 1);
+      }
+      Label success;
+      __ cmp(current_character(), 0x20);
+      __ j(equal, &success);
+      __ sub(Operand(current_character()), Immediate(0x09));
+      __ cmp(current_character(), 0x05);
+      BranchOrBacktrack(above_equal, on_no_match);
+      __ bind(&success);
+      return true;
+    }
+    return false;
+  case 'S':
+    if (check_offset) {
+      LoadCurrentCharacter(cp_offset, on_no_match, 1);
+    } else {
+      LoadCurrentCharacterUnchecked(cp_offset, 1);
+    }
+    if (mode_ == ASCII) {
+      __ cmp(current_character(), 0x20);
+      BranchOrBacktrack(equal, on_no_match);
+      __ sub(Operand(current_character()), Immediate(0x09));
+      __ cmp(current_character(), 0x05);
+      BranchOrBacktrack(below, on_no_match);
+      return true;
+    }
+    return false;
+  case 'd':
+    if (check_offset) {
+      LoadCurrentCharacter(cp_offset, on_no_match, 1);
+    } else {
+      LoadCurrentCharacterUnchecked(cp_offset, 1);
+    }
+    __ sub(Operand(current_character()), Immediate('0'));
+    __ cmp(current_character(), '9' - '0');
+    BranchOrBacktrack(greater_equal, on_no_match);
+    return true;
+  case 'D':
+    if (check_offset) {
+      LoadCurrentCharacter(cp_offset, on_no_match, 1);
+    } else {
+      LoadCurrentCharacterUnchecked(cp_offset, 1);
+    }
+    __ sub(Operand(current_character()), Immediate('0'));
+    __ cmp(current_character(), '9' - '0');
+    BranchOrBacktrack(below, on_no_match);
+    return true;
+  case '.': {
+    if (check_offset) {
+      LoadCurrentCharacter(cp_offset, on_no_match, 1);
+    } else {
+      LoadCurrentCharacterUnchecked(cp_offset, 1);
+    }
+    __ sub(Operand(current_character()), Immediate(0x0a));
+    __ mov(eax, current_character());
+    __ and_(current_character(), 0x01);
+    __ shr(eax, 1);
+    __ xor_(current_character(), Operand(eax));
+    BranchOrBacktrack(equal, on_no_match);
+    if (mode_ == UC16) {
+      __ cmp(eax, (0x2028 - 0x0a) >> 1);
+      BranchOrBacktrack(equal, on_no_match);
+    }
+    return true;
+  }
+  case '*':
+    if (check_offset) {
+      CheckPosition(cp_offset, on_no_match);
+    }
+    return true;
+  // No custom implementation (yet): w, W, s(UC16), S(UC16).
+  default:
+    return false;
+  }
+}
 
 void RegExpMacroAssemblerIA32::DispatchHalfNibbleMap(
     uc16 start,
     Label* half_nibble_map,
     const Vector<Label*>& destinations) {
   UNIMPLEMENTED();
   __ mov(eax, current_character());
   __ sub(Operand(eax), Immediate(start));
 
   __ mov(ecx, eax);
@@ skipping 231 matching lines @@
   return kIA32Implementation;
 }
 
 
 void RegExpMacroAssemblerIA32::LoadCurrentCharacter(int cp_offset,
                                                     Label* on_end_of_input,
                                                     bool check_bounds,
                                                     int characters) {
   ASSERT(cp_offset >= 0);
   ASSERT(cp_offset < (1<<30));  // Be sane! (And ensure negation works)
-  if (check_bounds) {
-    __ cmp(edi, -(cp_offset + characters) * char_size());
-    BranchOrBacktrack(greater, on_end_of_input);
-  }
+  CheckPosition(cp_offset + characters - 1, on_end_of_input);
   LoadCurrentCharacterUnchecked(cp_offset, characters);
 }
 
 
 void RegExpMacroAssemblerIA32::PopCurrentPosition() {
   __ pop(edi);
 }
 
 
 void RegExpMacroAssemblerIA32::PopRegister(int register_index) {
@@ skipping 134 matching lines @@
 Register RegExpMacroAssemblerIA32::current_character() {
   return edx;
 }
 
 
 size_t RegExpMacroAssemblerIA32::char_size() {
   return static_cast<size_t>(mode_);
 }
 
 
+void RegExpMacroAssemblerIA32::CheckPosition(int cp_offset,
+                                             Label* on_outside_input) {
+  __ cmp(edi, -cp_offset * char_size());
+  BranchOrBacktrack(greater_equal, on_outside_input);
+}
+
+
 void RegExpMacroAssemblerIA32::BranchOrBacktrack(Condition condition,
                                                  Label* to) {
   if (condition < 0) {  // No condition
     if (to == NULL) {
       Backtrack();
       return;
     }
     __ jmp(to);
     return;
   }
@@ skipping 91 matching lines @@
 
 
 void RegExpMacroAssemblerIA32::LoadConstantBufferAddress(Register reg,
                                                          ArraySlice* buffer) {
   __ mov(reg, buffer->array());
   __ add(Operand(reg), Immediate(buffer->base_offset()));
 }
 
 #undef __
 }}  // namespace v8::internal