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       --dump Causes  llvm-bcanalyzer  to dump the bitcode in a human readable
26              format.  This format is significantly different from LLVM assem‐
27              bly and provides details about the encoding of the bitcode file.
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29       --help Print a summary of command line options.
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EXIT STATUS

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

36       The following items are always printed by llvm-bcanalyzer.   They  com‐
37       prize the summary output.
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39       Bitcode Analysis Of Module
40          This just provides the name of the module for which bitcode analysis
41          is being generated.
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43       Bitcode Version Number
44          The bitcode version (not LLVM version) of the file read by the  ana‐
45          lyzer.
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47       File Size
48          The size, in bytes, of the entire bitcode file.
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50       Module Bytes
51          The  size, in bytes, of the module block.  Percentage is relative to
52          File Size.
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54       Function Bytes
55          The size, in bytes, of all the function blocks.  Percentage is rela‐
56          tive to File Size.
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58       Global Types Bytes
59          The  size,  in bytes, of the Global Types Pool.  Percentage is rela‐
60          tive to File Size.  This is the size of the definitions of all types
61          in the bitcode file.
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63       Constant Pool Bytes
64          The  size, in bytes, of the Constant Pool Blocks Percentage is rela‐
65          tive to File Size.
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67       Module Globals Bytes
68          Ths size, in bytes, of the Global  Variable  Definitions  and  their
69          initializers.  Percentage is relative to File Size.
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71       Instruction List Bytes
72          The  size,  in  bytes, of all the instruction lists in all the func‐
73          tions.  Percentage is relative to File Size.  Note that  this  value
74          is also included in the Function Bytes.
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76       Compaction Table Bytes
77          The  size,  in  bytes, of all the compaction tables in all the func‐
78          tions.  Percentage is relative to File Size.  Note that  this  value
79          is also included in the Function Bytes.
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81       Symbol Table Bytes
82          The  size,  in bytes, of all the symbol tables in all the functions.
83          Percentage is relative to File Size.  Note that this value  is  also
84          included in the Function Bytes.
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86       Dependent Libraries Bytes
87          The  size,  in bytes, of the list of dependent libraries in the mod‐
88          ule.  Percentage is relative to File Size.  Note that this value  is
89          also included in the Module Global Bytes.
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91       Number Of Bitcode Blocks
92          The total number of blocks of any kind in the bitcode file.
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94       Number Of Functions
95          The total number of function definitions in the bitcode file.
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97       Number Of Types
98          The total number of types defined in the Global Types Pool.
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100       Number Of Constants
101          The  total number of constants (of any type) defined in the Constant
102          Pool.
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104       Number Of Basic Blocks
105          The total number of basic blocks defined in  all  functions  in  the
106          bitcode file.
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108       Number Of Instructions
109          The  total  number  of  instructions defined in all functions in the
110          bitcode file.
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112       Number Of Long Instructions
113          The total number of long instructions defined in  all  functions  in
114          the bitcode file.  Long instructions are those taking greater than 4
115          bytes.  Typically long instructions are GetElementPtr  with  several
116          indices, PHI nodes, and calls to functions with large numbers of ar‐
117          guments.
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119       Number Of Operands
120          The total number of operands used in all instructions in the bitcode
121          file.
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123       Number Of Compaction Tables
124          The  total  number of compaction tables in all functions in the bit‐
125          code file.
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127       Number Of Symbol Tables
128          The total number of symbol tables in all functions  in  the  bitcode
129          file.
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131       Number Of Dependent Libs
132          The total number of dependent libraries found in the bitcode file.
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134       Total Instruction Size
135          The  total  size of the instructions in all functions in the bitcode
136          file.
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138       Average Instruction Size
139          The average number of bytes per instruction across all functions  in
140          the bitcode file.  This value is computed by dividing Total Instruc‐
141          tion Size by Number Of Instructions.
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143       Maximum Type Slot Number
144          The maximum value used for a type's slot number.  Larger slot number
145          values take more bytes to encode.
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147       Maximum Value Slot Number
148          The  maximum value used for a value's slot number.  Larger slot num‐
149          ber values take more bytes to encode.
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151       Bytes Per Value
152          The average size of a Value definition (of any type).  This is  com‐
153          puted  by  dividing  File  Size by the total number of values of any
154          type.
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156       Bytes Per Global
157          The average size of a global definition (constants and global  vari‐
158          ables).
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160       Bytes Per Function
161          The  average  number of bytes per function definition.  This is com‐
162          puted by dividing Function Bytes by Number Of Functions.
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164       # of VBR 32-bit Integers
165          The total number of 32-bit integers encoded using the  Variable  Bit
166          Rate encoding scheme.
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168       # of VBR 64-bit Integers
169          The  total  number of 64-bit integers encoded using the Variable Bit
170          Rate encoding scheme.
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172       # of VBR Compressed Bytes
173          The total number of bytes consumed by the 32-bit and 64-bit integers
174          that use the Variable Bit Rate encoding scheme.
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176       # of VBR Expanded Bytes
177          The  total  number  of  bytes  that  would have been consumed by the
178          32-bit and 64-bit integers had they not  been  compressed  with  the
179          Variable Bit Rage encoding scheme.
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181       Bytes Saved With VBR
182          The  total  number of bytes saved by using the Variable Bit Rate en‐
183          coding scheme.  The percentage is relative  to  #  of  VBR  Expanded
184          Bytes.
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DETAILED OUTPUT DEFINITIONS

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

248       llvm-dis(1), LLVM Bitcode File Format
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AUTHOR

251       Maintained by the LLVM Team (https://llvm.org/).
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254       2003-2023, LLVM Project
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25916                                2023-07-20                LLVM-BCANALYZER(1)
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