28 #include "oops/arrayOop.hpp"
29
30 // An objArrayOop is an array containing oops.
31 // Evaluating "String arg[10]" will create an objArrayOop.
32
33 class objArrayOopDesc : public arrayOopDesc {
34 friend class objArrayKlass;
35 friend class Runtime1;
36 friend class psPromotionManager;
37 friend class CSetMarkOopClosure;
38 friend class G1ParScanPartialArrayClosure;
39
40 template <class T> T* obj_at_addr(int index) const {
41 assert(is_within_bounds(index), "index out of bounds");
42 return &((T*)base())[index];
43 }
44
45 private:
46 // Give size of objArrayOop in HeapWords minus the header
47 static int array_size(int length) {
48 const int OopsPerHeapWord = HeapWordSize/heapOopSize;
49 assert(OopsPerHeapWord >= 1 && (HeapWordSize % heapOopSize == 0),
50 "Else the following (new) computation would be in error");
51 #ifdef ASSERT
52 // The old code is left in for sanity-checking; it'll
53 // go away pretty soon. XXX
54 // Without UseCompressedOops, this is simply:
55 // oop->length() * HeapWordsPerOop;
56 // With narrowOops, HeapWordsPerOop is 1/2 or equal 0 as an integer.
57 // The oop elements are aligned up to wordSize
58 const int HeapWordsPerOop = heapOopSize/HeapWordSize;
59 int old_res;
60 if (HeapWordsPerOop > 0) {
61 old_res = length * HeapWordsPerOop;
62 } else {
63 old_res = align_size_up(length, OopsPerHeapWord)/OopsPerHeapWord;
64 }
65 #endif // ASSERT
66 int res = ((uint)length + OopsPerHeapWord - 1)/OopsPerHeapWord;
67 assert(res == old_res, "Inconsistency between old and new.");
68 return res;
69 }
70
71 public:
72 // Returns the offset of the first element.
73 static int base_offset_in_bytes() {
74 return arrayOopDesc::base_offset_in_bytes(T_OBJECT);
75 }
76
77 // base is the address following the header.
78 HeapWord* base() const { return (HeapWord*) arrayOopDesc::base(T_OBJECT); }
79
80 // Accessing
81 oop obj_at(int index) const {
82 // With UseCompressedOops decode the narrow oop in the objArray to an
83 // uncompressed oop. Otherwise this is simply a "*" operator.
84 if (UseCompressedOops) {
85 return load_decode_heap_oop(obj_at_addr<narrowOop>(index));
86 } else {
87 return load_decode_heap_oop(obj_at_addr<oop>(index));
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28 #include "oops/arrayOop.hpp"
29
30 // An objArrayOop is an array containing oops.
31 // Evaluating "String arg[10]" will create an objArrayOop.
32
33 class objArrayOopDesc : public arrayOopDesc {
34 friend class objArrayKlass;
35 friend class Runtime1;
36 friend class psPromotionManager;
37 friend class CSetMarkOopClosure;
38 friend class G1ParScanPartialArrayClosure;
39
40 template <class T> T* obj_at_addr(int index) const {
41 assert(is_within_bounds(index), "index out of bounds");
42 return &((T*)base())[index];
43 }
44
45 private:
46 // Give size of objArrayOop in HeapWords minus the header
47 static int array_size(int length) {
48 const uint OopsPerHeapWord = HeapWordSize/heapOopSize;
49 assert(OopsPerHeapWord >= 1 && (HeapWordSize % heapOopSize == 0),
50 "Else the following (new) computation would be in error");
51 uint res = ((uint)length + OopsPerHeapWord - 1)/OopsPerHeapWord;
52 #ifdef ASSERT
53 // The old code is left in for sanity-checking; it'll
54 // go away pretty soon. XXX
55 // Without UseCompressedOops, this is simply:
56 // oop->length() * HeapWordsPerOop;
57 // With narrowOops, HeapWordsPerOop is 1/2 or equal 0 as an integer.
58 // The oop elements are aligned up to wordSize
59 const uint HeapWordsPerOop = heapOopSize/HeapWordSize;
60 uint old_res;
61 if (HeapWordsPerOop > 0) {
62 old_res = length * HeapWordsPerOop;
63 } else {
64 old_res = align_size_up((uint)length, OopsPerHeapWord)/OopsPerHeapWord;
65 }
66 assert(res == old_res, "Inconsistency between old and new.");
67 #endif // ASSERT
68 return res;
69 }
70
71 public:
72 // Returns the offset of the first element.
73 static int base_offset_in_bytes() {
74 return arrayOopDesc::base_offset_in_bytes(T_OBJECT);
75 }
76
77 // base is the address following the header.
78 HeapWord* base() const { return (HeapWord*) arrayOopDesc::base(T_OBJECT); }
79
80 // Accessing
81 oop obj_at(int index) const {
82 // With UseCompressedOops decode the narrow oop in the objArray to an
83 // uncompressed oop. Otherwise this is simply a "*" operator.
84 if (UseCompressedOops) {
85 return load_decode_heap_oop(obj_at_addr<narrowOop>(index));
86 } else {
87 return load_decode_heap_oop(obj_at_addr<oop>(index));
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