- Avoid allocating an overly large stack frame in the irregexp

src/interpreter-irregexp.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 97 matching lines @@
         printf("%c", b);
       } else {
         printf(".");
       }
     }
     printf("\n");
   }
 }
 
 
-#define BYTECODE(name)                                  \
-  case BC_##name:                                       \
-    TraceInterpreter(code_base,                         \
-                     pc,                                \
-                     backtrack_sp - backtrack_stack,    \
-                     current,                           \
-                     current_char,                      \
-                     BC_##name##_LENGTH,                \
+#define BYTECODE(name)                                    \
+  case BC_##name:                                         \
+    TraceInterpreter(code_base,                           \
+                     pc,                                  \
+                     backtrack_sp - backtrack_stack_base, \
+                     current,                             \
+                     current_char,                        \
+                     BC_##name##_LENGTH,                  \
                      #name);
 #else
-#define BYTECODE(name)                                  \
+#define BYTECODE(name)                                    \
   case BC_##name:
 #endif
 
 
 static int32_t Load32Aligned(const byte* pc) {
   ASSERT((reinterpret_cast<intptr_t>(pc) & 3) == 0);
   return *reinterpret_cast<const int32_t *>(pc);
 }
 
 
 static int32_t Load16Aligned(const byte* pc) {
   ASSERT((reinterpret_cast<intptr_t>(pc) & 1) == 0);
   return *reinterpret_cast<const uint16_t *>(pc);
 }
 
 
 template <typename Char>
 static bool RawMatch(const byte* code_base,
                      Vector<const Char> subject,
                      int* registers,
                      int current,
                      uint32_t current_char) {
   const byte* pc = code_base;
   static const int kBacktrackStackSize = 10000;
-  int backtrack_stack[kBacktrackStackSize];
+  // Use a SmartPointer here to ensure that the memory gets freed when the
+  // matching finishes.
+  SmartPointer<int> backtrack_stack(NewArray<int>(kBacktrackStackSize));
+  int* backtrack_stack_base = *backtrack_stack;
+  int* backtrack_sp = backtrack_stack_base;
   int backtrack_stack_space = kBacktrackStackSize;
-  int* backtrack_sp = backtrack_stack;
 #ifdef DEBUG
   if (FLAG_trace_regexp_bytecodes) {
     PrintF("\n\nStart bytecode interpreter\n\n");
   }
 #endif
   while (true) {
     int32_t insn = Load32Aligned(pc);
     switch (insn & BYTECODE_MASK) {
       BYTECODE(BREAK)
         UNREACHABLE();
@@ skipping 29 matching lines @@
         break;
       BYTECODE(SET_REGISTER_TO_CP)
         registers[insn >> BYTECODE_SHIFT] = current + Load32Aligned(pc + 4);
         pc += BC_SET_REGISTER_TO_CP_LENGTH;
         break;
       BYTECODE(SET_CP_TO_REGISTER)
         current = registers[insn >> BYTECODE_SHIFT];
         pc += BC_SET_CP_TO_REGISTER_LENGTH;
         break;
       BYTECODE(SET_REGISTER_TO_SP)
-        registers[insn >> BYTECODE_SHIFT] = backtrack_sp - backtrack_stack;
+        registers[insn >> BYTECODE_SHIFT] = backtrack_sp - backtrack_stack_base;
         pc += BC_SET_REGISTER_TO_SP_LENGTH;
         break;
       BYTECODE(SET_SP_TO_REGISTER)
-        backtrack_sp = backtrack_stack + registers[insn >> BYTECODE_SHIFT];
+        backtrack_sp = backtrack_stack_base + registers[insn >> BYTECODE_SHIFT];
         backtrack_stack_space = kBacktrackStackSize -
-                                (backtrack_sp - backtrack_stack);
+                                (backtrack_sp - backtrack_stack_base);
         pc += BC_SET_SP_TO_REGISTER_LENGTH;
         break;
       BYTECODE(POP_CP)
         backtrack_stack_space++;
         --backtrack_sp;
         current = *backtrack_sp;
         pc += BC_POP_CP_LENGTH;
         break;
       BYTECODE(POP_BT)
         backtrack_stack_space++;
@@ skipping 366 matching lines @@
     if (start_position != 0) previous_char = subject_vector[start_position - 1];
     return RawMatch(code_base,
                     subject_vector,
                     registers,
                     start_position,
                     previous_char);
   }
 }
 
 } }  // namespace v8::internal