Limit end-anchored regexps to testing end of string where possible.

src/arm/regexp-macro-assembler-arm.cc

 // Copyright 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:
 //
 //     * 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 124 matching lines @@
 }
 
 
 int RegExpMacroAssemblerARM::stack_limit_slack()  {
   return RegExpStack::kStackLimitSlack;
 }
 
 
 void RegExpMacroAssemblerARM::AdvanceCurrentPosition(int by) {
   if (by != 0) {
-    Label inside_string;
     __ add(current_input_offset(),
            current_input_offset(), Operand(by * char_size()));
   }
 }
 
 
 void RegExpMacroAssemblerARM::AdvanceRegister(int reg, int by) {
   ASSERT(reg >= 0);
   ASSERT(reg < num_registers_);
   if (by != 0) {
@@ skipping 764 matching lines @@
 }
 
 
 void RegExpMacroAssemblerARM::ReadStackPointerFromRegister(int reg) {
   __ ldr(backtrack_stackpointer(), register_location(reg));
   __ ldr(r0, MemOperand(frame_pointer(), kStackHighEnd));
   __ add(backtrack_stackpointer(), backtrack_stackpointer(), Operand(r0));
 }
 
 
+void RegExpMacroAssemblerARM::SetCurrentPositionFromEnd(int by) {
+  Label after_position;

[Lasse Reichstein, 2010/10/19 13:39:24]

There is no NearLabel for ARM.

+  __ cmp(current_input_offset(), Operand(-by * char_size()));
+  __ b(ge, &after_position);

[Lasse Reichstein, 2010/10/19 13:39:24]

Comparison must be signed, since either value can be zero as well as negative.

+  __ mov(current_input_offset(), Operand(-by * char_size()));
+  // On RegExp code entry (where this operation is used), the character before
+  // the current position is expected to be already loaded.
+  // We have advanced the position, so it's safe to read backwards.
+  LoadCurrentCharacterUnchecked(-1, 1);
+  __ bind(&after_position);
+}
+
+
 void RegExpMacroAssemblerARM::SetRegister(int register_index, int to) {
   ASSERT(register_index >= num_saved_registers_);  // Reserved for positions!
   __ mov(r0, Operand(to));
   __ str(r0, register_location(register_index));
 }
 
 
 void RegExpMacroAssemblerARM::Succeed() {
   __ jmp(&success_label_);
 }
@@ skipping 310 matching lines @@
   __ ldr(pc, MemOperand(sp, stack_alignment, PostIndex));
 }
 
 #undef __
 
 #endif  // V8_INTERPRETED_REGEXP
 
 }}  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM