Fix a crash when generating forward jumps to labels at very high assembly offsets

test/cctest/test-assembler-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
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 //
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@@ skipping 1391 matching lines @@
   t.dst4 = 0;
   Object* dummy = CALL_GENERATED_CODE(f, &t, 0, 0, 0, 0);
   USE(dummy);
   CHECK_EQ(0x12130304, t.dst0);
   CHECK_EQ(0x01021213, t.dst1);
   CHECK_EQ(0x00010003, t.dst2);
   CHECK_EQ(0x00000003, t.dst3);
   CHECK_EQ(0x11121313, t.dst4);
 }
 
+
+TEST(17) {
+  // Test generating labels at high addresses.
+  // Should not assert.
+  CcTest::InitializeVM();
+  Isolate* isolate = Isolate::Current();
+  HandleScope scope(isolate);
+
+  // Generate a code segment that will be longer than 2^24 bytes.
+  Assembler assm(isolate, NULL, 0);
+  for (size_t i = 0; i < 8388608; ++i) {  // 2^23

[Benedikt Meurer, 2013/07/31 11:35:55]

nit: use 1 << 23 instead of 8388608.

[Kimmo Kinnunen, 2013/08/01 06:06:53]

Done.

+    __ nop();
+  }
+
+  Label target;
+  __ b(eq, &target);
+  __ bind(&target);
+  __ nop();
+}
+
+
 #undef __