summaryrefslogtreecommitdiffstats
path: root/libdex/InstrUtils.h
blob: 9728cd453b8343cc1acd039d5e61ced849c56fe1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * Dalvik instruction utility functions.
 */
#ifndef _LIBDEX_INSTRUTILS
#define _LIBDEX_INSTRUTILS

#include "DexFile.h"
#include "OpCode.h"

/*
 * Dalvik-defined instruction formats.
 *
 * (This defines InstructionFormat as an unsigned char to reduce the size
 * of the table.  This isn't necessary with some compilers, which use an
 * integer width appropriate for the number of enum values.)
 * 
 * If you add or delete a format, you have to change some or all of:
 *  - this enum
 *  - the switch inside dexDecodeInstruction() in InstrUtils.c
 *  - the switch inside dumpInstruction() in DexDump.c
 */
typedef unsigned char InstructionFormat;
enum InstructionFormat {
    kFmtUnknown = 0,
    kFmt10x,        // op
    kFmt12x,        // op vA, vB
    kFmt11n,        // op vA, #+B
    kFmt11x,        // op vAA
    kFmt10t,        // op +AA
    kFmt20bc,       // op AA, thing@BBBB
    kFmt20t,        // op +AAAA
    kFmt22x,        // op vAA, vBBBB
    kFmt21t,        // op vAA, +BBBB
    kFmt21s,        // op vAA, #+BBBB
    kFmt21h,        // op vAA, #+BBBB00000[00000000]
    kFmt21c,        // op vAA, thing@BBBB
    kFmt23x,        // op vAA, vBB, vCC
    kFmt22b,        // op vAA, vBB, #+CC
    kFmt22t,        // op vA, vB, +CCCC
    kFmt22s,        // op vA, vB, #+CCCC
    kFmt22c,        // op vA, vB, thing@CCCC
    kFmt22cs,       // [opt] op vA, vB, field offset CCCC
    kFmt32x,        // op vAAAA, vBBBB
    kFmt30t,        // op +AAAAAAAA
    kFmt31t,        // op vAA, +BBBBBBBB
    kFmt31i,        // op vAA, #+BBBBBBBB
    kFmt31c,        // op vAA, thing@BBBBBBBB
    kFmt35c,        // op {vC, vD, vE, vF, vG}, thing@BBBB (B: count, A: vG)
    kFmt35ms,       // [opt] invoke-virtual+super
    kFmt35fs,       // [opt] invoke-interface
    kFmt3rc,        // op {vCCCC .. v(CCCC+AA-1)}, meth@BBBB
    kFmt3rms,       // [opt] invoke-virtual+super/range
    kFmt3rfs,       // [opt] invoke-interface/range
    kFmt3inline,    // [opt] inline invoke
    kFmt51l,        // op vAA, #+BBBBBBBBBBBBBBBB
};

/*
 * Holds the contents of a decoded instruction.
 */
typedef struct DecodedInstruction {
    u4      vA;
    u4      vB;
    u8      vB_wide;        /* for kFmt51l */
    u4      vC;
    u4      arg[5];         /* vC/D/E/F/G in invoke or filled-new-array */
    OpCode  opCode;
} DecodedInstruction;

/*
 * Instruction width, a value in the range -3 to 5.
 */
typedef signed char InstructionWidth;

/*
 * Instruction flags, used by the verifier to determine where control
 * can flow to next.
 */
typedef unsigned char InstructionFlags;
enum InstructionFlags {
    kInstrCanBranch     = 1,        // conditional or unconditional branch
    kInstrCanContinue   = 1 << 1,   // flow can continue to next statement
    kInstrCanSwitch     = 1 << 2,   // switch statement
    kInstrCanThrow      = 1 << 3,   // could cause an exception to be thrown
    kInstrCanReturn     = 1 << 4,   // returns, no additional statements
    kInstrInvoke        = 1 << 5,   // a flavor of invoke
    kInstrUnconditional = 1 << 6,   // unconditional branch
};


/*
 * Allocate and populate a 256-element array with instruction widths.  A
 * width of zero means the entry does not exist.
 */
InstructionWidth* dexCreateInstrWidthTable(void);

/*
 * Returns the width of the specified instruction, or 0 if not defined.
 * Optimized instructions use negative values.
 */
DEX_INLINE int dexGetInstrWidth(const InstructionWidth* widths, OpCode opCode)
{
   // assert(/*opCode >= 0 &&*/ opCode < kNumDalvikInstructions);
    return widths[opCode];
}

/*
 * Return the width of the specified instruction, or 0 if not defined.
 */
DEX_INLINE int dexGetInstrWidthAbs(const InstructionWidth* widths,OpCode opCode)
{
    //assert(/*opCode >= 0 &&*/ opCode < kNumDalvikInstructions);

    int val = dexGetInstrWidth(widths, opCode);
    if (val < 0)
        val = -val;
    /* XXX - the no-compare trick may be a cycle slower on ARM */
    return val;
}

/*
 * Return the width of the specified instruction, or 0 if not defined.  Also
 * works for special OP_NOP entries, including switch statement data tables
 * and array data.
 */
int dexGetInstrOrTableWidthAbs(const InstructionWidth* widths, const u2* insns);


/*
 * Allocate and populate a 256-element array with instruction flags.
 */
InstructionFlags* dexCreateInstrFlagsTable(void);

/*
 * Returns the flags for the specified opcode.
 */
DEX_INLINE int dexGetInstrFlags(const InstructionFlags* flags, OpCode opCode)
{
    //assert(/*opCode >= 0 &&*/ opCode < kNumDalvikInstructions);
    return flags[opCode];
}


/*
 * Allocate and populate a 256-element array with instruction formats.
 */
InstructionFormat* dexCreateInstrFormatTable(void);

/*
 * Return the instruction format for the specified opcode.
 */
DEX_INLINE InstructionFormat dexGetInstrFormat(const InstructionFormat* fmts,
    OpCode opCode)
{
    //assert(/*opCode >= 0 &&*/ opCode < kNumDalvikInstructions);
    return fmts[opCode];
}

/*
 * Decode the instruction pointed to by "insns".
 */
void dexDecodeInstruction(const InstructionFormat* fmts, const u2* insns,
    DecodedInstruction* pDec);

#endif /*_LIBDEX_INSTRUTILS*/