Mercurial > hg > graal-compiler
annotate src/share/vm/memory/memRegion.cpp @ 1722:effb55808a18
Merge
author | johnc |
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date | Wed, 18 Aug 2010 17:44:33 -0400 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 // A very simple data structure representing a contigous word-aligned | |
26 // region of address space. | |
27 | |
28 #include "incls/_precompiled.incl" | |
29 #include "incls/_memRegion.cpp.incl" | |
30 | |
31 MemRegion MemRegion::intersection(const MemRegion mr2) const { | |
32 MemRegion res; | |
33 HeapWord* res_start = MAX2(start(), mr2.start()); | |
34 HeapWord* res_end = MIN2(end(), mr2.end()); | |
35 if (res_start < res_end) { | |
36 res.set_start(res_start); | |
37 res.set_end(res_end); | |
38 } | |
39 return res; | |
40 } | |
41 | |
42 MemRegion MemRegion::_union(const MemRegion mr2) const { | |
43 // If one region is empty, return the other | |
44 if (is_empty()) return mr2; | |
45 if (mr2.is_empty()) return MemRegion(start(), end()); | |
46 | |
47 // Otherwise, regions must overlap or be adjacent | |
48 assert(((start() <= mr2.start()) && (end() >= mr2.start())) || | |
49 ((mr2.start() <= start()) && (mr2.end() >= start())), | |
50 "non-adjacent or overlapping regions"); | |
51 MemRegion res; | |
52 HeapWord* res_start = MIN2(start(), mr2.start()); | |
53 HeapWord* res_end = MAX2(end(), mr2.end()); | |
54 res.set_start(res_start); | |
55 res.set_end(res_end); | |
56 return res; | |
57 } | |
58 | |
59 MemRegion MemRegion::minus(const MemRegion mr2) const { | |
60 // There seem to be 6 cases: | |
61 // |this MemRegion| | |
62 // |strictly below| | |
63 // |overlap beginning| | |
64 // |interior| | |
65 // |overlap ending| | |
66 // |strictly above| | |
67 // |completely overlapping| | |
68 // We can't deal with an interior case because it would | |
69 // produce two disjoint regions as a result. | |
70 // We aren't trying to be optimal in the number of tests below, | |
71 // but the order is important to distinguish the strictly cases | |
72 // from the overlapping cases. | |
73 if (mr2.end() <= start()) { | |
74 // strictly below | |
75 return MemRegion(start(), end()); | |
76 } | |
77 if (mr2.start() <= start() && mr2.end() <= end()) { | |
78 // overlap beginning | |
79 return MemRegion(mr2.end(), end()); | |
80 } | |
81 if (mr2.start() >= end()) { | |
82 // strictly above | |
83 return MemRegion(start(), end()); | |
84 } | |
85 if (mr2.start() >= start() && mr2.end() >= end()) { | |
86 // overlap ending | |
87 return MemRegion(start(), mr2.start()); | |
88 } | |
89 if (mr2.start() <= start() && mr2.end() >= end()) { | |
90 // completely overlapping | |
91 return MemRegion(); | |
92 } | |
93 if (mr2.start() > start() && mr2.end() < end()) { | |
94 // interior | |
95 guarantee(false, "MemRegion::minus, but interior"); | |
96 return MemRegion(); | |
97 } | |
98 ShouldNotReachHere(); | |
99 return MemRegion(); | |
100 } |