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1llvm-bcanalyzer - LLVM bitcode analyzer
2=======================================
3
4SYNOPSIS
5--------
6
7:program:`llvm-bcanalyzer` [*options*] [*filename*]
8
9DESCRIPTION
10-----------
11
12The :program:`llvm-bcanalyzer` command is a small utility for analyzing bitcode
13files.  The tool reads a bitcode file (such as generated with the
14:program:`llvm-as` tool) and produces a statistical report on the contents of
15the bitcode file.  The tool can also dump a low level but human readable
16version of the bitcode file.  This tool is probably not of much interest or
17utility except for those working directly with the bitcode file format.  Most
18LLVM users can just ignore this tool.
19
20If *filename* is omitted or is ``-``, then :program:`llvm-bcanalyzer` reads its
21input from standard input.  This is useful for combining the tool into a
22pipeline.  Output is written to the standard output.
23
24OPTIONS
25-------
26
27.. program:: llvm-bcanalyzer
28
29.. option:: -nodetails
30
31 Causes :program:`llvm-bcanalyzer` to abbreviate its output by writing out only
32 a module level summary.  The details for individual functions are not
33 displayed.
34
35.. option:: -dump
36
37 Causes :program:`llvm-bcanalyzer` to dump the bitcode in a human readable
38 format.  This format is significantly different from LLVM assembly and
39 provides details about the encoding of the bitcode file.
40
41.. option:: -verify
42
43 Causes :program:`llvm-bcanalyzer` to verify the module produced by reading the
44 bitcode.  This ensures that the statistics generated are based on a consistent
45 module.
46
47.. option:: -help
48
49 Print a summary of command line options.
50
51EXIT STATUS
52-----------
53
54If :program:`llvm-bcanalyzer` succeeds, it will exit with 0.  Otherwise, if an
55error occurs, it will exit with a non-zero value, usually 1.
56
57SUMMARY OUTPUT DEFINITIONS
58--------------------------
59
60The following items are always printed by llvm-bcanalyzer.  They comprize the
61summary output.
62
63**Bitcode Analysis Of Module**
64
65 This just provides the name of the module for which bitcode analysis is being
66 generated.
67
68**Bitcode Version Number**
69
70 The bitcode version (not LLVM version) of the file read by the analyzer.
71
72**File Size**
73
74 The size, in bytes, of the entire bitcode file.
75
76**Module Bytes**
77
78 The size, in bytes, of the module block.  Percentage is relative to File Size.
79
80**Function Bytes**
81
82 The size, in bytes, of all the function blocks.  Percentage is relative to File
83 Size.
84
85**Global Types Bytes**
86
87 The size, in bytes, of the Global Types Pool.  Percentage is relative to File
88 Size.  This is the size of the definitions of all types in the bitcode file.
89
90**Constant Pool Bytes**
91
92 The size, in bytes, of the Constant Pool Blocks Percentage is relative to File
93 Size.
94
95**Module Globals Bytes**
96
97 Ths size, in bytes, of the Global Variable Definitions and their initializers.
98 Percentage is relative to File Size.
99
100**Instruction List Bytes**
101
102 The size, in bytes, of all the instruction lists in all the functions.
103 Percentage is relative to File Size.  Note that this value is also included in
104 the Function Bytes.
105
106**Compaction Table Bytes**
107
108 The size, in bytes, of all the compaction tables in all the functions.
109 Percentage is relative to File Size.  Note that this value is also included in
110 the Function Bytes.
111
112**Symbol Table Bytes**
113
114 The size, in bytes, of all the symbol tables in all the functions.  Percentage is
115 relative to File Size.  Note that this value is also included in the Function
116 Bytes.
117
118**Dependent Libraries Bytes**
119
120 The size, in bytes, of the list of dependent libraries in the module.  Percentage
121 is relative to File Size.  Note that this value is also included in the Module
122 Global Bytes.
123
124**Number Of Bitcode Blocks**
125
126 The total number of blocks of any kind in the bitcode file.
127
128**Number Of Functions**
129
130 The total number of function definitions in the bitcode file.
131
132**Number Of Types**
133
134 The total number of types defined in the Global Types Pool.
135
136**Number Of Constants**
137
138 The total number of constants (of any type) defined in the Constant Pool.
139
140**Number Of Basic Blocks**
141
142 The total number of basic blocks defined in all functions in the bitcode file.
143
144**Number Of Instructions**
145
146 The total number of instructions defined in all functions in the bitcode file.
147
148**Number Of Long Instructions**
149
150 The total number of long instructions defined in all functions in the bitcode
151 file.  Long instructions are those taking greater than 4 bytes.  Typically long
152 instructions are GetElementPtr with several indices, PHI nodes, and calls to
153 functions with large numbers of arguments.
154
155**Number Of Operands**
156
157 The total number of operands used in all instructions in the bitcode file.
158
159**Number Of Compaction Tables**
160
161 The total number of compaction tables in all functions in the bitcode file.
162
163**Number Of Symbol Tables**
164
165 The total number of symbol tables in all functions in the bitcode file.
166
167**Number Of Dependent Libs**
168
169 The total number of dependent libraries found in the bitcode file.
170
171**Total Instruction Size**
172
173 The total size of the instructions in all functions in the bitcode file.
174
175**Average Instruction Size**
176
177 The average number of bytes per instruction across all functions in the bitcode
178 file.  This value is computed by dividing Total Instruction Size by Number Of
179 Instructions.
180
181**Maximum Type Slot Number**
182
183 The maximum value used for a type's slot number.  Larger slot number values take
184 more bytes to encode.
185
186**Maximum Value Slot Number**
187
188 The maximum value used for a value's slot number.  Larger slot number values take
189 more bytes to encode.
190
191**Bytes Per Value**
192
193 The average size of a Value definition (of any type).  This is computed by
194 dividing File Size by the total number of values of any type.
195
196**Bytes Per Global**
197
198 The average size of a global definition (constants and global variables).
199
200**Bytes Per Function**
201
202 The average number of bytes per function definition.  This is computed by
203 dividing Function Bytes by Number Of Functions.
204
205**# of VBR 32-bit Integers**
206
207 The total number of 32-bit integers encoded using the Variable Bit Rate
208 encoding scheme.
209
210**# of VBR 64-bit Integers**
211
212 The total number of 64-bit integers encoded using the Variable Bit Rate encoding
213 scheme.
214
215**# of VBR Compressed Bytes**
216
217 The total number of bytes consumed by the 32-bit and 64-bit integers that use
218 the Variable Bit Rate encoding scheme.
219
220**# of VBR Expanded Bytes**
221
222 The total number of bytes that would have been consumed by the 32-bit and 64-bit
223 integers had they not been compressed with the Variable Bit Rage encoding
224 scheme.
225
226**Bytes Saved With VBR**
227
228 The total number of bytes saved by using the Variable Bit Rate encoding scheme.
229 The percentage is relative to # of VBR Expanded Bytes.
230
231DETAILED OUTPUT DEFINITIONS
232---------------------------
233
234The following definitions occur only if the -nodetails option was not given.
235The detailed output provides additional information on a per-function basis.
236
237**Type**
238
239 The type signature of the function.
240
241**Byte Size**
242
243 The total number of bytes in the function's block.
244
245**Basic Blocks**
246
247 The number of basic blocks defined by the function.
248
249**Instructions**
250
251 The number of instructions defined by the function.
252
253**Long Instructions**
254
255 The number of instructions using the long instruction format in the function.
256
257**Operands**
258
259 The number of operands used by all instructions in the function.
260
261**Instruction Size**
262
263 The number of bytes consumed by instructions in the function.
264
265**Average Instruction Size**
266
267 The average number of bytes consumed by the instructions in the function.
268 This value is computed by dividing Instruction Size by Instructions.
269
270**Bytes Per Instruction**
271
272 The average number of bytes used by the function per instruction.  This value
273 is computed by dividing Byte Size by Instructions.  Note that this is not the
274 same as Average Instruction Size.  It computes a number relative to the total
275 function size not just the size of the instruction list.
276
277**Number of VBR 32-bit Integers**
278
279 The total number of 32-bit integers found in this function (for any use).
280
281**Number of VBR 64-bit Integers**
282
283 The total number of 64-bit integers found in this function (for any use).
284
285**Number of VBR Compressed Bytes**
286
287 The total number of bytes in this function consumed by the 32-bit and 64-bit
288 integers that use the Variable Bit Rate encoding scheme.
289
290**Number of VBR Expanded Bytes**
291
292 The total number of bytes in this function that would have been consumed by
293 the 32-bit and 64-bit integers had they not been compressed with the Variable
294 Bit Rate encoding scheme.
295
296**Bytes Saved With VBR**
297
298 The total number of bytes saved in this function by using the Variable Bit
299 Rate encoding scheme.  The percentage is relative to # of VBR Expanded Bytes.
300
301SEE ALSO
302--------
303
304:doc:`/CommandGuide/llvm-dis`, :doc:`/BitCodeFormat`
305
306