Generated code for substring slices in ia32.

src/objects.h

 // Copyright 2011 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
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 };
 const uint32_t kIsIndirectStringMask = 0x1;
 const uint32_t kIsIndirectStringTag = 0x1;
 STATIC_ASSERT((kSeqStringTag & kIsIndirectStringMask) == 0);
 STATIC_ASSERT((kExternalStringTag & kIsIndirectStringMask) == 0);
 STATIC_ASSERT(
     (kConsStringTag & kIsIndirectStringMask) == kIsIndirectStringTag);
 STATIC_ASSERT(
     (kSlicedStringTag & kIsIndirectStringMask) == kIsIndirectStringTag);
 
+// Use this mask to distinguish between cons and slice only after making
+// sure that the string is one of the two (an indirect string).
+const uint32_t kSlicedNotConsMask = kSlicedStringTag & ~kConsStringTag;
+STATIC_ASSERT(IS_POWER_OF_TWO(kSlicedNotConsMask) && kSlicedNotConsMask != 0);
+
 // If bit 7 is clear, then bit 3 indicates whether this two-byte
 // string actually contains ascii data.
 const uint32_t kAsciiDataHintMask = 0x08;
 const uint32_t kAsciiDataHintTag = 0x08;
 
 
 // A ConsString with an empty string as the right side is a candidate
 // for being shortcut by the garbage collector unless it is a
 // symbol. It's not common to have non-flat symbols, so we do not
 // shortcut them thereby avoiding turning symbols into strings. See
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     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_