Generated code for substring slices in x64 and arm.

test/cctest/test-strings.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 
 // Check that we can traverse very deep stacks of ConsStrings using
 // StringInputBuffer.  Check that Get(int) works on very deep stacks
 // of ConsStrings.  These operations may not be very fast, but they
 // should be possible without getting errors due to too deep recursion.
 
 #include <stdlib.h>
 
 #include "v8.h"
@@ skipping 511 matching lines @@
   CHECK(!string->IsSlicedString());
 
   string = FACTORY->NewSubString(string, 0, 26);
   CHECK(!string->IsSlicedString());
   result = CompileRun(crosscheck);
   CHECK(result->IsString());
   string = v8::Utils::OpenHandle(v8::String::Cast(*result));
   CHECK(string->IsSlicedString());
   CHECK_EQ("bcdefghijklmnopqrstuvwxy", *(string->ToCString()));
 }
+
+
+TEST(SliceFromSlice) {
+  // This tests whether a slice that contains the entire parent string
+  // actually creates a new string (it should not).
+  FLAG_string_slices = true;
+  InitializeVM();
+  HandleScope scope;
+  v8::Local<v8::Value> result;
+  Handle<String> string;
+  const char* init = "var str = 'abcdefghijklmnopqrstuvwxyz';";
+  const char* slice = "var slice = str.slice(1,-1); slice";
+  const char* slice_from_slice = "slice.slice(1,-1);";
+
+  CompileRun(init);
+  result = CompileRun(slice);
+  CHECK(result->IsString());
+  string = v8::Utils::OpenHandle(v8::String::Cast(*result));
+  CHECK(string->IsSlicedString());
+  CHECK(SlicedString::cast(*string)->parent()->IsSeqString());
+  CHECK_EQ("bcdefghijklmnopqrstuvwxy", *(string->ToCString()));
+
+  result = CompileRun(slice_from_slice);
+  CHECK(result->IsString());
+  string = v8::Utils::OpenHandle(v8::String::Cast(*result));
+  CHECK(string->IsSlicedString());
+  CHECK(SlicedString::cast(*string)->parent()->IsSeqString());
+  CHECK_EQ("cdefghijklmnopqrstuvwx", *(string->ToCString()));
+}