1 /*
2 * Copyright (c) 2000, 2008, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 package sun.jvm.hotspot.debugger;
26
27 /** <P> This is the bottom-most interface which abstracts address
28 access for both debugging and introspection. In the situation of
29 debugging a target VM, these routines can throw the specified
30 RuntimeExceptions to indicate failure and allow recovery of the
31 debugging system. If these are used for introspecting the current
32 VM and implementing functionality in it, however, it is expected
33 that these kinds of failures will not occur and, in fact, a crash
34 will occur if the situation arises where they would have been
35 thrown. </P>
36
37 <P> Addresses are immutable. Further, it was decided not to expose
38 the representation of the Address (and provide a corresponding
39 factory method from, for example, long to Address). Unfortunately,
40 because of the existence of C and "reuse" of low bits of pointers,
41 it is occasionally necessary to perform logical operations like
42 masking off the low bits of an "address". While these operations
43 could be used to generate arbitrary Address objects, allowing this
44 is not the intent of providing these operations. </P>
45
46 <P> This interface is able to fetch all Java primitive types,
47 addresses, oops, and C integers of arbitrary size (see @see
48 sun.jvm.hotspot.types.CIntegerType for further discussion). Note
49 that the result of the latter is restricted to fitting into a
50 64-bit value and the high-order bytes will be silently discarded
51 if too many bytes are requested. </P>
52
53 <P> Implementations may have restrictions, for example that the
54 Java-related routines may not be called until a certain point in
55 the bootstrapping process once the sizes of the Java primitive
56 types are known. (The current implementation has that property.)
57 </P>
58
59 <P> A note of warning: in C addresses, when represented as
60 integers, are usually represented with unsigned types.
61 Unfortunately, there are no unsigned primitive types in Java, so
62 care will have to be taken in the implementation of this interface
63 if using longs as the representation for 64-bit correctness. This
64 is not so simple for the comparison operators. </P> */
65
66 public interface Address {
67
68 /** This is stated explicitly here because it is important for
69 implementations to understand that equals() and hashCode() must
70 absolutely, positively work properly -- i.e., two Address
71 objects representing the same address are both equal (via
72 equals()) and have the same hash code. */
73 public boolean equals(Object arg);
74
75 /** This is stated explicitly here because it is important for
76 implementations to understand that equals() and hashCode() must
77 absolutely, positively work properly -- i.e., two Address
78 objects representing the same address are both equal (via
79 equals()) and have the same hash code. */
80 public int hashCode();
81
82 //
83 // C/C++-related routines
84 //
85
86 public long getCIntegerAt (long offset, long numBytes, boolean isUnsigned)
87 throws UnmappedAddressException, UnalignedAddressException;
88 /** This returns null if the address at the given offset is NULL. */
89 public Address getAddressAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
90 /** Returns the decoded address at the given offset */
91 public Address getCompOopAddressAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
92 public Address getCompKlassAddressAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
93
94 //
95 // Java-related routines
96 //
97
98 public boolean getJBooleanAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
99 public byte getJByteAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
100 public char getJCharAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
101 public double getJDoubleAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
102 public float getJFloatAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
103 public int getJIntAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
104 public long getJLongAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
105 public short getJShortAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
106 /** This returns null if the address at the given offset is NULL. */
107 public OopHandle getOopHandleAt (long offset)
108 throws UnmappedAddressException, UnalignedAddressException, NotInHeapException;
109 public OopHandle getCompOopHandleAt (long offset)
110 throws UnmappedAddressException, UnalignedAddressException, NotInHeapException;
111
112 //
113 // C/C++-related mutators. These throw UnmappedAddressException if
114 // the target is read-only (for example, a core file rather than an
115 // active process), if the target address is unmapped, or if it is
116 // read-only. The implementation may supply extra detail messages.
117 //
118
119 /** Sets a C integer numBytes in size at the specified offset. Note
120 that there is no "unsigned" flag for the accessor since the
121 value will not be sign-extended; the number of bytes are simply
122 copied from the value into the target address space. */
123 public void setCIntegerAt(long offset, long numBytes, long value);
124
125 /** Sets an Address at the specified location. */
126 public void setAddressAt(long offset, Address value);
127
128 //
129 // Java-related mutators -- see above.
130 //
131
132 public void setJBooleanAt (long offset, boolean value)
133 throws UnmappedAddressException, UnalignedAddressException;
134 public void setJByteAt (long offset, byte value)
135 throws UnmappedAddressException, UnalignedAddressException;
136 public void setJCharAt (long offset, char value)
137 throws UnmappedAddressException, UnalignedAddressException;
138 public void setJDoubleAt (long offset, double value)
139 throws UnmappedAddressException, UnalignedAddressException;
140 public void setJFloatAt (long offset, float value)
141 throws UnmappedAddressException, UnalignedAddressException;
142 public void setJIntAt (long offset, int value)
143 throws UnmappedAddressException, UnalignedAddressException;
144 public void setJLongAt (long offset, long value)
145 throws UnmappedAddressException, UnalignedAddressException;
146 public void setJShortAt (long offset, short value)
147 throws UnmappedAddressException, UnalignedAddressException;
148 public void setOopHandleAt (long offset, OopHandle value)
149 throws UnmappedAddressException, UnalignedAddressException;
150
151 //
152 // Arithmetic operations -- necessary evil.
153 //
154
155 /** This throws an UnsupportedOperationException if this address happens
156 to actually be an OopHandle, because interior object pointers
157 are not allowed. Negative offsets are allowed and handle the
158 subtraction case. */
159 public Address addOffsetTo (long offset) throws UnsupportedOperationException;
160
161 /** This method had to be added in order to support heap iteration
162 in the debugging system, and is effectively the dangerous
163 operation of allowing interior object pointers. For this reason
164 it was kept as a separate API and its use is forbidden in the
165 non-debugging (i.e., reflective system) case. It is strongly
166 recommended that this not be called by clients: it is currently
167 wrapped up in the Space's iteration mechanism. */
168 public OopHandle addOffsetToAsOopHandle(long offset) throws UnsupportedOperationException;
169
170 /** Performs the subtraction "this - arg", returning the resulting
171 offset in bytes. Note that this must handle a null argument
172 properly, and can be used to convert an Address into a long for
173 further manipulation, but that the reverse conversion is not
174 possible. (FIXME: any signed/unsigned issues? Should this work
175 for OopHandles?) */
176 public long minus(Address arg);
177
178 /** Performs unsigned comparison "this < arg".
179 (FIXME: should this work for OopHandles?) */
180 public boolean lessThan (Address arg);
181 /** Performs unsigned comparison "this <= arg".
182 (FIXME: should this work for OopHandles?) */
183 public boolean lessThanOrEqual (Address arg);
184 /** Performs unsigned comparison "this > arg".
185 (FIXME: should this work for OopHandles?) */
186 public boolean greaterThan (Address arg);
187 /** Performs unsigned comparison "this >= arg".
188 (FIXME: should this work for OopHandles?) */
189 public boolean greaterThanOrEqual(Address arg);
190
191 /** This throws an UnsupportedOperationException if this address happens
192 to actually be an OopHandle. Performs a logical "and" operation
193 of the bits of the address and the mask (least significant bits
194 of the Address and the mask are aligned) and returns the result
195 as an Address. Returns null if the result was zero. */
196 public Address andWithMask(long mask) throws UnsupportedOperationException;
197
198 /** This throws an UnsupportedOperationException if this address happens
199 to actually be an OopHandle. Performs a logical "or" operation
200 of the bits of the address and the mask (least significant bits
201 of the Address and the mask are aligned) and returns the result
202 as an Address. Returns null if the result was zero. */
203 public Address orWithMask(long mask) throws UnsupportedOperationException;
204
205 /** This throws an UnsupportedOperationException if this address happens
206 to actually be an OopHandle. Performs a logical "exclusive or"
207 operation of the bits of the address and the mask (least
208 significant bits of the Address and the mask are aligned) and
209 returns the result as an Address. Returns null if the result was
210 zero. */
211 public Address xorWithMask(long mask) throws UnsupportedOperationException;
212
213 // return address as long integer.
214 public long asLongValue();
215 }