1 /*
2 * Copyright 2000-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any 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
93 //
94 // Java-related routines
95 //
96
97 public boolean getJBooleanAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
98 public byte getJByteAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
99 public char getJCharAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
100 public double getJDoubleAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
101 public float getJFloatAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
102 public int getJIntAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
103 public long getJLongAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
104 public short getJShortAt (long offset) throws UnmappedAddressException, UnalignedAddressException;
105 /** This returns null if the address at the given offset is NULL. */
106 public OopHandle getOopHandleAt (long offset)
107 throws UnmappedAddressException, UnalignedAddressException, NotInHeapException;
108 public OopHandle getCompOopHandleAt (long offset)
109 throws UnmappedAddressException, UnalignedAddressException, NotInHeapException;
110
111 //
112 // C/C++-related mutators. These throw UnmappedAddressException if
113 // the target is read-only (for example, a core file rather than an
114 // active process), if the target address is unmapped, or if it is
115 // read-only. The implementation may supply extra detail messages.
116 //
117
118 /** Sets a C integer numBytes in size at the specified offset. Note
119 that there is no "unsigned" flag for the accessor since the
120 value will not be sign-extended; the number of bytes are simply
121 copied from the value into the target address space. */
122 public void setCIntegerAt(long offset, long numBytes, long value);
123
124 /** Sets an Address at the specified location. */
125 public void setAddressAt(long offset, Address value);
126
127 //
128 // Java-related mutators -- see above.
129 //
130
131 public void setJBooleanAt (long offset, boolean value)
132 throws UnmappedAddressException, UnalignedAddressException;
133 public void setJByteAt (long offset, byte value)
134 throws UnmappedAddressException, UnalignedAddressException;
135 public void setJCharAt (long offset, char value)
136 throws UnmappedAddressException, UnalignedAddressException;
137 public void setJDoubleAt (long offset, double value)
138 throws UnmappedAddressException, UnalignedAddressException;
139 public void setJFloatAt (long offset, float value)
140 throws UnmappedAddressException, UnalignedAddressException;
141 public void setJIntAt (long offset, int value)
142 throws UnmappedAddressException, UnalignedAddressException;
143 public void setJLongAt (long offset, long value)
144 throws UnmappedAddressException, UnalignedAddressException;
145 public void setJShortAt (long offset, short value)
146 throws UnmappedAddressException, UnalignedAddressException;
147 public void setOopHandleAt (long offset, OopHandle value)
148 throws UnmappedAddressException, UnalignedAddressException;
149
150 //
151 // Arithmetic operations -- necessary evil.
152 //
153
154 /** This throws an UnsupportedOperationException if this address happens
155 to actually be an OopHandle, because interior object pointers
156 are not allowed. Negative offsets are allowed and handle the
157 subtraction case. */
158 public Address addOffsetTo (long offset) throws UnsupportedOperationException;
159
160 /** This method had to be added in order to support heap iteration
161 in the debugging system, and is effectively the dangerous
162 operation of allowing interior object pointers. For this reason
163 it was kept as a separate API and its use is forbidden in the
164 non-debugging (i.e., reflective system) case. It is strongly
165 recommended that this not be called by clients: it is currently
166 wrapped up in the Space's iteration mechanism. */
167 public OopHandle addOffsetToAsOopHandle(long offset) throws UnsupportedOperationException;
168
169 /** Performs the subtraction "this - arg", returning the resulting
170 offset in bytes. Note that this must handle a null argument
171 properly, and can be used to convert an Address into a long for
172 further manipulation, but that the reverse conversion is not
173 possible. (FIXME: any signed/unsigned issues? Should this work
174 for OopHandles?) */
175 public long minus(Address arg);
176
177 /** Performs unsigned comparison "this < arg".
178 (FIXME: should this work for OopHandles?) */
179 public boolean lessThan (Address arg);
180 /** Performs unsigned comparison "this <= arg".
181 (FIXME: should this work for OopHandles?) */
182 public boolean lessThanOrEqual (Address arg);
183 /** Performs unsigned comparison "this > arg".
184 (FIXME: should this work for OopHandles?) */
185 public boolean greaterThan (Address arg);
186 /** Performs unsigned comparison "this >= arg".
187 (FIXME: should this work for OopHandles?) */
188 public boolean greaterThanOrEqual(Address arg);
189
190 /** This throws an UnsupportedOperationException if this address happens
191 to actually be an OopHandle. Performs a logical "and" operation
192 of the bits of the address and the mask (least significant bits
193 of the Address and the mask are aligned) and returns the result
194 as an Address. Returns null if the result was zero. */
195 public Address andWithMask(long mask) throws UnsupportedOperationException;
196
197 /** This throws an UnsupportedOperationException if this address happens
198 to actually be an OopHandle. Performs a logical "or" operation
199 of the bits of the address and the mask (least significant bits
200 of the Address and the mask are aligned) and returns the result
201 as an Address. Returns null if the result was zero. */
202 public Address orWithMask(long mask) throws UnsupportedOperationException;
203
204 /** This throws an UnsupportedOperationException if this address happens
205 to actually be an OopHandle. Performs a logical "exclusive or"
206 operation of the bits of the address and the mask (least
207 significant bits of the Address and the mask are aligned) and
208 returns the result as an Address. Returns null if the result was
209 zero. */
210 public Address xorWithMask(long mask) throws UnsupportedOperationException;
211 }