CodeVerify.h revision 5d709784bbf5001012d7f25172927d46f6c1abe1 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/*
18 * Dalvik bytecode verifier.
19 */
20#ifndef _DALVIK_CODEVERIFY
21#define _DALVIK_CODEVERIFY
22
23#include "analysis/VerifySubs.h"
24
25
26/*
27 * Enumeration for register type values.  The "hi" piece of a 64-bit value
28 * MUST immediately follow the "lo" piece in the enumeration, so we can check
29 * that hi==lo+1.
30 *
31 * Assignment of constants:
32 *   [-MAXINT,-32768)   : integer
33 *   [-32768,-128)      : short
34 *   [-128,0)           : byte
35 *   0                  : zero
36 *   1                  : one
37 *   [2,128)            : posbyte
38 *   [128,32768)        : posshort
39 *   [32768,65536)      : char
40 *   [65536,MAXINT]     : integer
41 *
42 * Allowed "implicit" widening conversions:
43 *   zero -> boolean, posbyte, byte, posshort, short, char, integer, ref (null)
44 *   one -> boolean, posbyte, byte, posshort, short, char, integer
45 *   boolean -> posbyte, byte, posshort, short, char, integer
46 *   posbyte -> posshort, short, integer, char
47 *   byte -> short, integer
48 *   posshort -> integer, char
49 *   short -> integer
50 *   char -> integer
51 *
52 * In addition, all of the above can convert to "float".
53 *
54 * We're more careful with integer values than the spec requires.  The
55 * motivation is to restrict byte/char/short to the correct range of values.
56 * For example, if a method takes a byte argument, we don't want to allow
57 * the code to load the constant "1024" and pass it in.
58 */
59enum {
60    kRegTypeUnknown = 0,    /* initial state; use value=0 so calloc works */
61    kRegTypeUninit = 1,     /* MUST be odd to distinguish from pointer */
62    kRegTypeConflict,       /* merge clash makes this reg's type unknowable */
63
64    /*
65     * Category-1nr types.  The order of these is chiseled into a couple
66     * of tables, so don't add, remove, or reorder if you can avoid it.
67     */
68#define kRegType1nrSTART    kRegTypeFloat
69    kRegTypeFloat,
70    kRegTypeZero,           /* 32-bit 0, could be Boolean, Int, Float, or Ref */
71    kRegTypeOne,            /* 32-bit 1, could be Boolean, Int, Float */
72    kRegTypeBoolean,        /* must be 0 or 1 */
73    kRegTypePosByte,        /* byte, known positive (can become char) */
74    kRegTypeByte,
75    kRegTypePosShort,       /* short, known positive (can become char) */
76    kRegTypeShort,
77    kRegTypeChar,
78    kRegTypeInteger,
79#define kRegType1nrEND      kRegTypeInteger
80
81    kRegTypeLongLo,         /* lower-numbered register; endian-independent */
82    kRegTypeLongHi,
83    kRegTypeDoubleLo,
84    kRegTypeDoubleHi,
85
86    /*
87     * Enumeration max; this is used with "full" (32-bit) RegType values.
88     *
89     * Anything larger than this is a ClassObject or uninit ref.  Mask off
90     * all but the low 8 bits; if you're left with kRegTypeUninit, pull
91     * the uninit index out of the high 24.  Because kRegTypeUninit has an
92     * odd value, there is no risk of a particular ClassObject pointer bit
93     * pattern being confused for it (assuming our class object allocator
94     * uses word alignment).
95     */
96    kRegTypeMAX
97};
98#define kRegTypeUninitMask  0xff
99#define kRegTypeUninitShift 8
100
101/*
102 * RegType holds information about the type of data held in a register.
103 * For most types it's a simple enum.  For reference types it holds a
104 * pointer to the ClassObject, and for uninitialized references it holds
105 * an index into the UninitInstanceMap.
106 */
107typedef u4 RegType;
108
109/* table with merge logic for primitive types */
110extern const char gDvmMergeTab[kRegTypeMAX][kRegTypeMAX];
111
112
113/*
114 * Returns "true" if the flags indicate that this address holds the start
115 * of an instruction.
116 */
117INLINE bool dvmInsnIsOpcode(const InsnFlags* insnFlags, int addr) {
118    return (insnFlags[addr] & kInsnFlagWidthMask) != 0;
119}
120
121/*
122 * Extract the unsigned 16-bit instruction width from "flags".
123 */
124INLINE int dvmInsnGetWidth(const InsnFlags* insnFlags, int addr) {
125    return insnFlags[addr] & kInsnFlagWidthMask;
126}
127
128/*
129 * Changed?
130 */
131INLINE bool dvmInsnIsChanged(const InsnFlags* insnFlags, int addr) {
132    return (insnFlags[addr] & kInsnFlagChanged) != 0;
133}
134INLINE void dvmInsnSetChanged(InsnFlags* insnFlags, int addr, bool changed)
135{
136    if (changed)
137        insnFlags[addr] |= kInsnFlagChanged;
138    else
139        insnFlags[addr] &= ~kInsnFlagChanged;
140}
141
142/*
143 * Visited?
144 */
145INLINE bool dvmInsnIsVisited(const InsnFlags* insnFlags, int addr) {
146    return (insnFlags[addr] & kInsnFlagVisited) != 0;
147}
148INLINE void dvmInsnSetVisited(InsnFlags* insnFlags, int addr, bool changed)
149{
150    if (changed)
151        insnFlags[addr] |= kInsnFlagVisited;
152    else
153        insnFlags[addr] &= ~kInsnFlagVisited;
154}
155
156/*
157 * Visited or changed?
158 */
159INLINE bool dvmInsnIsVisitedOrChanged(const InsnFlags* insnFlags, int addr) {
160    return (insnFlags[addr] & (kInsnFlagVisited|kInsnFlagChanged)) != 0;
161}
162
163/*
164 * In a "try" block?
165 */
166INLINE bool dvmInsnIsInTry(const InsnFlags* insnFlags, int addr) {
167    return (insnFlags[addr] & kInsnFlagInTry) != 0;
168}
169INLINE void dvmInsnSetInTry(InsnFlags* insnFlags, int addr, bool inTry)
170{
171    assert(inTry);
172    //if (inTry)
173        insnFlags[addr] |= kInsnFlagInTry;
174    //else
175    //    insnFlags[addr] &= ~kInsnFlagInTry;
176}
177
178/*
179 * Instruction is a branch target or exception handler?
180 */
181INLINE bool dvmInsnIsBranchTarget(const InsnFlags* insnFlags, int addr) {
182    return (insnFlags[addr] & kInsnFlagBranchTarget) != 0;
183}
184INLINE void dvmInsnSetBranchTarget(InsnFlags* insnFlags, int addr,
185    bool isBranch)
186{
187    assert(isBranch);
188    //if (isBranch)
189        insnFlags[addr] |= kInsnFlagBranchTarget;
190    //else
191    //    insnFlags[addr] &= ~kInsnFlagBranchTarget;
192}
193
194/*
195 * Instruction is a GC point?
196 */
197INLINE bool dvmInsnIsGcPoint(const InsnFlags* insnFlags, int addr) {
198    return (insnFlags[addr] & kInsnFlagGcPoint) != 0;
199}
200INLINE void dvmInsnSetGcPoint(InsnFlags* insnFlags, int addr,
201    bool isBranch)
202{
203    assert(isBranch);
204    //if (isBranch)
205        insnFlags[addr] |= kInsnFlagGcPoint;
206    //else
207    //    insnFlags[addr] &= ~kInsnFlagGcPoint;
208}
209
210
211/*
212 * Table that maps uninitialized instances to classes, based on the
213 * address of the new-instance instruction.
214 */
215typedef struct UninitInstanceMap {
216    int numEntries;
217    struct {
218        int             addr;   /* code offset, or -1 for method arg ("this") */
219        ClassObject*    clazz;  /* class created at this address */
220    } map[1];
221} UninitInstanceMap;
222#define kUninitThisArgAddr  (-1)
223#define kUninitThisArgSlot  0
224
225/*
226 * Create a new UninitInstanceMap.
227 */
228UninitInstanceMap* dvmCreateUninitInstanceMap(const Method* meth,
229    const InsnFlags* insnFlags, int newInstanceCount);
230
231/*
232 * Release the storage associated with an UninitInstanceMap.
233 */
234void dvmFreeUninitInstanceMap(UninitInstanceMap* uninitMap);
235
236/*
237 * Associate a class with an address.  Returns the map slot index, or -1
238 * if the address isn't listed in the map (shouldn't happen) or if a
239 * different class is already associated with the address (shouldn't
240 * happen either).
241 */
242//int dvmSetUninitInstance(UninitInstanceMap* uninitMap, int addr,
243//    ClassObject* clazz);
244
245/*
246 * Return the class associated with an uninitialized reference.  Pass in
247 * the map index.
248 */
249//ClassObject* dvmGetUninitInstance(const UninitInstanceMap* uninitMap, int idx);
250
251/*
252 * Clear the class associated with an uninitialized reference.  Pass in
253 * the map index.
254 */
255//void dvmClearUninitInstance(UninitInstanceMap* uninitMap, int idx);
256
257
258/*
259 * Verify bytecode in "meth".  "insnFlags" should be populated with
260 * instruction widths and "in try" flags.
261 */
262bool dvmVerifyCodeFlow(const Method* meth, InsnFlags* insnFlags,
263    UninitInstanceMap* uninitMap);
264
265#endif /*_DALVIK_CODEVERIFY*/
266