1LLVM-BCANALYZER(1)                   LLVM                   LLVM-BCANALYZER(1)
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NAME

6       llvm-bcanalyzer - LLVM bitcode analyzer
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SYNOPSIS

9       llvm-bcanalyzer [options] [filename]
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DESCRIPTION

12       The  llvm-bcanalyzer  command  is a small utility for analyzing bitcode
13       files.  The tool reads a bitcode  file  (such  as  generated  with  the
14       llvm-as  tool) and produces a statistical report on the contents of the
15       bitcode file.  The tool can also dump a low level  but  human  readable
16       version  of the bitcode file.  This tool is probably not of much inter‐
17       est or utility except for those working directly with the bitcode  file
18       format.  Most LLVM users can just ignore this tool.
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20       If  filename  is  omitted or is -, then llvm-bcanalyzer reads its input
21       from standard input.  This is useful for  combining  the  tool  into  a
22       pipeline.  Output is written to the standard output.
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OPTIONS

25       -nodetails
26              Causes  llvm-bcanalyzer  to abbreviate its output by writing out
27              only a module level summary.  The details for  individual  func‐
28              tions are not displayed.
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30       -dump  Causes  llvm-bcanalyzer  to dump the bitcode in a human readable
31              format.  This format is significantly different from LLVM assem‐
32              bly and provides details about the encoding of the bitcode file.
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34       -verify
35              Causes  llvm-bcanalyzer to verify the module produced by reading
36              the bitcode.  This ensures that  the  statistics  generated  are
37              based on a consistent module.
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39       -help  Print a summary of command line options.
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EXIT STATUS

42       If llvm-bcanalyzer succeeds, it will exit with 0.  Otherwise, if an er‐
43       ror occurs, it will exit with a non-zero value, usually 1.
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SUMMARY OUTPUT DEFINITIONS

46       The following items are always printed by llvm-bcanalyzer.   They  com‐
47       prize the summary output.
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49       Bitcode Analysis Of Module
50          This just provides the name of the module for which bitcode analysis
51          is being generated.
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53       Bitcode Version Number
54          The bitcode version (not LLVM version) of the file read by the  ana‐
55          lyzer.
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57       File Size
58          The size, in bytes, of the entire bitcode file.
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60       Module Bytes
61          The  size, in bytes, of the module block.  Percentage is relative to
62          File Size.
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64       Function Bytes
65          The size, in bytes, of all the function blocks.  Percentage is rela‐
66          tive to File Size.
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68       Global Types Bytes
69          The  size,  in bytes, of the Global Types Pool.  Percentage is rela‐
70          tive to File Size.  This is the size of the definitions of all types
71          in the bitcode file.
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73       Constant Pool Bytes
74          The  size, in bytes, of the Constant Pool Blocks Percentage is rela‐
75          tive to File Size.
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77       Module Globals Bytes
78          Ths size, in bytes, of the Global  Variable  Definitions  and  their
79          initializers.  Percentage is relative to File Size.
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81       Instruction List Bytes
82          The  size,  in  bytes, of all the instruction lists in all the func‐
83          tions.  Percentage is relative to File Size.  Note that  this  value
84          is also included in the Function Bytes.
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86       Compaction Table Bytes
87          The  size,  in  bytes, of all the compaction tables in all the func‐
88          tions.  Percentage is relative to File Size.  Note that  this  value
89          is also included in the Function Bytes.
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91       Symbol Table Bytes
92          The  size,  in bytes, of all the symbol tables in all the functions.
93          Percentage is relative to File Size.  Note that this value  is  also
94          included in the Function Bytes.
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96       Dependent Libraries Bytes
97          The  size,  in bytes, of the list of dependent libraries in the mod‐
98          ule.  Percentage is relative to File Size.  Note that this value  is
99          also included in the Module Global Bytes.
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101       Number Of Bitcode Blocks
102          The total number of blocks of any kind in the bitcode file.
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104       Number Of Functions
105          The total number of function definitions in the bitcode file.
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107       Number Of Types
108          The total number of types defined in the Global Types Pool.
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110       Number Of Constants
111          The  total number of constants (of any type) defined in the Constant
112          Pool.
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114       Number Of Basic Blocks
115          The total number of basic blocks defined in  all  functions  in  the
116          bitcode file.
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118       Number Of Instructions
119          The  total  number  of  instructions defined in all functions in the
120          bitcode file.
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122       Number Of Long Instructions
123          The total number of long instructions defined in  all  functions  in
124          the bitcode file.  Long instructions are those taking greater than 4
125          bytes.  Typically long instructions are GetElementPtr  with  several
126          indices, PHI nodes, and calls to functions with large numbers of ar‐
127          guments.
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129       Number Of Operands
130          The total number of operands used in all instructions in the bitcode
131          file.
132
133       Number Of Compaction Tables
134          The  total  number of compaction tables in all functions in the bit‐
135          code file.
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137       Number Of Symbol Tables
138          The total number of symbol tables in all functions  in  the  bitcode
139          file.
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141       Number Of Dependent Libs
142          The total number of dependent libraries found in the bitcode file.
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144       Total Instruction Size
145          The  total  size of the instructions in all functions in the bitcode
146          file.
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148       Average Instruction Size
149          The average number of bytes per instruction across all functions  in
150          the bitcode file.  This value is computed by dividing Total Instruc‐
151          tion Size by Number Of Instructions.
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153       Maximum Type Slot Number
154          The maximum value used for a type's slot number.  Larger slot number
155          values take more bytes to encode.
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157       Maximum Value Slot Number
158          The  maximum value used for a value's slot number.  Larger slot num‐
159          ber values take more bytes to encode.
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161       Bytes Per Value
162          The average size of a Value definition (of any type).  This is  com‐
163          puted  by  dividing  File  Size by the total number of values of any
164          type.
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166       Bytes Per Global
167          The average size of a global definition (constants and global  vari‐
168          ables).
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170       Bytes Per Function
171          The  average  number of bytes per function definition.  This is com‐
172          puted by dividing Function Bytes by Number Of Functions.
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174       # of VBR 32-bit Integers
175          The total number of 32-bit integers encoded using the  Variable  Bit
176          Rate encoding scheme.
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178       # of VBR 64-bit Integers
179          The  total  number of 64-bit integers encoded using the Variable Bit
180          Rate encoding scheme.
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182       # of VBR Compressed Bytes
183          The total number of bytes consumed by the 32-bit and 64-bit integers
184          that use the Variable Bit Rate encoding scheme.
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186       # of VBR Expanded Bytes
187          The  total  number  of  bytes  that  would have been consumed by the
188          32-bit and 64-bit integers had they not  been  compressed  with  the
189          Variable Bit Rage encoding scheme.
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191       Bytes Saved With VBR
192          The  total  number of bytes saved by using the Variable Bit Rate en‐
193          coding scheme.  The percentage is relative  to  #  of  VBR  Expanded
194          Bytes.
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DETAILED OUTPUT DEFINITIONS

197       The  following  definitions occur only if the -nodetails option was not
198       given.  The  detailed  output  provides  additional  information  on  a
199       per-function basis.
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201       Type
202          The type signature of the function.
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204       Byte Size
205          The total number of bytes in the function's block.
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207       Basic Blocks
208          The number of basic blocks defined by the function.
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210       Instructions
211          The number of instructions defined by the function.
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213       Long Instructions
214          The  number of instructions using the long instruction format in the
215          function.
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217       Operands
218          The number of operands used by all instructions in the function.
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220       Instruction Size
221          The number of bytes consumed by instructions in the function.
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223       Average Instruction Size
224          The average number of bytes consumed  by  the  instructions  in  the
225          function.   This  value  is computed by dividing Instruction Size by
226          Instructions.
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228       Bytes Per Instruction
229          The average number of bytes used by the  function  per  instruction.
230          This  value is computed by dividing Byte Size by Instructions.  Note
231          that this is not the same as Average Instruction Size.  It  computes
232          a  number  relative  to the total function size not just the size of
233          the instruction list.
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235       Number of VBR 32-bit Integers
236          The total number of 32-bit integers found in this function (for  any
237          use).
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239       Number of VBR 64-bit Integers
240          The  total number of 64-bit integers found in this function (for any
241          use).
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243       Number of VBR Compressed Bytes
244          The total number of bytes in this function consumed  by  the  32-bit
245          and 64-bit integers that use the Variable Bit Rate encoding scheme.
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247       Number of VBR Expanded Bytes
248          The total number of bytes in this function that would have been con‐
249          sumed by the 32-bit and 64-bit integers had they not been compressed
250          with the Variable Bit Rate encoding scheme.
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252       Bytes Saved With VBR
253          The  total number of bytes saved in this function by using the Vari‐
254          able Bit Rate encoding scheme.  The percentage is relative to  #  of
255          VBR Expanded Bytes.
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SEE ALSO

258       /CommandGuide/llvm-dis, /BitCodeFormat
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AUTHOR

261       Maintained by The LLVM Team (http://llvm.org/).
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264       2003-2021, LLVM Project
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2697                                 2021-03-30                LLVM-BCANALYZER(1)
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