LLVM-BCANALYZER(1)



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

NAME
       llvm-bcanalyzer - LLVM bitcode analyzer

SYNOPSIS
       llvm-bcanalyzer [options] [filename]

DESCRIPTION
       The  llvm-bcanalyzer  command  is a small utility for analyzing bitcode
       files.  The tool reads a bitcode  file  (such  as  generated  with  the
       llvm-as  tool) and produces a statistical report on the contents of the
       bitcode file.  The tool can also dump a low level  but  human  readable
       version  of the bitcode file.  This tool is probably not of much inter-
       est or utility except for those working directly with the bitcode  file
       format.  Most LLVM users can just ignore this tool.

       If  filename  is  omitted or is -, then llvm-bcanalyzer reads its input
       from standard input.  This is useful for  combining  the  tool  into  a
       pipeline.  Output is written to the standard output.

OPTIONS
       -nodetails
              Causes  llvm-bcanalyzer  to abbreviate its output by writing out
              only a module level summary.  The details for  individual  func-
              tions are not displayed.

       -dump  Causes  llvm-bcanalyzer  to dump the bitcode in a human readable
              format.  This format is significantly different from LLVM assem-
              bly and provides details about the encoding of the bitcode file.

       -verify
              Causes  llvm-bcanalyzer to verify the module produced by reading
              the bitcode.  This ensures that  the  statistics  generated  are
              based on a consistent module.

       -help  Print a summary of command line options.

EXIT STATUS
       If llvm-bcanalyzer succeeds, it will exit with 0.  Otherwise, if an er-
       ror occurs, it will exit with a non-zero value, usually 1.

SUMMARY OUTPUT DEFINITIONS
       The following items are always printed by llvm-bcanalyzer.   They  com-
       prize the summary output.

       Bitcode Analysis Of Module
          This just provides the name of the module for which bitcode analysis
          is being generated.

       Bitcode Version Number
          The bitcode version (not LLVM version) of the file read by the  ana-
          lyzer.

       File Size
          The size, in bytes, of the entire bitcode file.

       Module Bytes
          The  size, in bytes, of the module block.  Percentage is relative to
          File Size.

       Function Bytes
          The size, in bytes, of all the function blocks.  Percentage is rela-
          tive to File Size.

       Global Types Bytes
          The  size,  in bytes, of the Global Types Pool.  Percentage is rela-
          tive to File Size.  This is the size of the definitions of all types
          in the bitcode file.

       Constant Pool Bytes
          The  size, in bytes, of the Constant Pool Blocks Percentage is rela-
          tive to File Size.

       Module Globals Bytes
          Ths size, in bytes, of the Global  Variable  Definitions  and  their
          initializers.  Percentage is relative to File Size.

       Instruction List Bytes
          The  size,  in  bytes, of all the instruction lists in all the func-
          tions.  Percentage is relative to File Size.  Note that  this  value
          is also included in the Function Bytes.

       Compaction Table Bytes
          The  size,  in  bytes, of all the compaction tables in all the func-
          tions.  Percentage is relative to File Size.  Note that  this  value
          is also included in the Function Bytes.

       Symbol Table Bytes
          The  size,  in bytes, of all the symbol tables in all the functions.
          Percentage is relative to File Size.  Note that this value  is  also
          included in the Function Bytes.

       Dependent Libraries Bytes
          The  size,  in bytes, of the list of dependent libraries in the mod-
          ule.  Percentage is relative to File Size.  Note that this value  is
          also included in the Module Global Bytes.

       Number Of Bitcode Blocks
          The total number of blocks of any kind in the bitcode file.

       Number Of Functions
          The total number of function definitions in the bitcode file.

       Number Of Types
          The total number of types defined in the Global Types Pool.

       Number Of Constants
          The  total number of constants (of any type) defined in the Constant
          Pool.

       Number Of Basic Blocks
          The total number of basic blocks defined in  all  functions  in  the
          bitcode file.

       Number Of Instructions
          The  total  number  of  instructions defined in all functions in the
          bitcode file.

       Number Of Long Instructions
          The total number of long instructions defined in  all  functions  in
          the bitcode file.  Long instructions are those taking greater than 4
          bytes.  Typically long instructions are GetElementPtr  with  several
          indices, PHI nodes, and calls to functions with large numbers of ar-
          guments.

       Number Of Operands
          The total number of operands used in all instructions in the bitcode
          file.

       Number Of Compaction Tables
          The  total  number of compaction tables in all functions in the bit-
          code file.

       Number Of Symbol Tables
          The total number of symbol tables in all functions  in  the  bitcode
          file.

       Number Of Dependent Libs
          The total number of dependent libraries found in the bitcode file.

       Total Instruction Size
          The  total  size of the instructions in all functions in the bitcode
          file.

       Average Instruction Size
          The average number of bytes per instruction across all functions  in
          the bitcode file.  This value is computed by dividing Total Instruc-
          tion Size by Number Of Instructions.

       Maximum Type Slot Number
          The maximum value used for a type's slot number.  Larger slot number
          values take more bytes to encode.

       Maximum Value Slot Number
          The  maximum value used for a value's slot number.  Larger slot num-
          ber values take more bytes to encode.

       Bytes Per Value
          The average size of a Value definition (of any type).  This is  com-
          puted  by  dividing  File  Size by the total number of values of any
          type.

       Bytes Per Global
          The average size of a global definition (constants and global  vari-
          ables).

       Bytes Per Function
          The  average  number of bytes per function definition.  This is com-
          puted by dividing Function Bytes by Number Of Functions.

       # of VBR 32-bit Integers
          The total number of 32-bit integers encoded using the  Variable  Bit
          Rate encoding scheme.

       # of VBR 64-bit Integers
          The  total  number of 64-bit integers encoded using the Variable Bit
          Rate encoding scheme.

       # of VBR Compressed Bytes
          The total number of bytes consumed by the 32-bit and 64-bit integers
          that use the Variable Bit Rate encoding scheme.

       # of VBR Expanded Bytes
          The  total  number  of  bytes  that  would have been consumed by the
          32-bit and 64-bit integers had they not  been  compressed  with  the
          Variable Bit Rage encoding scheme.

       Bytes Saved With VBR
          The  total  number of bytes saved by using the Variable Bit Rate en-
          coding scheme.  The percentage is relative  to  #  of  VBR  Expanded
          Bytes.

DETAILED OUTPUT DEFINITIONS
       The  following  definitions occur only if the -nodetails option was not
       given.  The  detailed  output  provides  additional  information  on  a
       per-function basis.

       Type
          The type signature of the function.

       Byte Size
          The total number of bytes in the function's block.

       Basic Blocks
          The number of basic blocks defined by the function.

       Instructions
          The number of instructions defined by the function.

       Long Instructions
          The  number of instructions using the long instruction format in the
          function.

       Operands
          The number of operands used by all instructions in the function.

       Instruction Size
          The number of bytes consumed by instructions in the function.

       Average Instruction Size
          The average number of bytes consumed  by  the  instructions  in  the
          function.   This  value  is computed by dividing Instruction Size by
          Instructions.

       Bytes Per Instruction
          The average number of bytes used by the  function  per  instruction.
          This  value is computed by dividing Byte Size by Instructions.  Note
          that this is not the same as Average Instruction Size.  It  computes
          a  number  relative  to the total function size not just the size of
          the instruction list.

       Number of VBR 32-bit Integers
          The total number of 32-bit integers found in this function (for  any
          use).

       Number of VBR 64-bit Integers
          The  total number of 64-bit integers found in this function (for any
          use).

       Number of VBR Compressed Bytes
          The total number of bytes in this function consumed  by  the  32-bit
          and 64-bit integers that use the Variable Bit Rate encoding scheme.

       Number of VBR Expanded Bytes
          The total number of bytes in this function that would have been con-
          sumed by the 32-bit and 64-bit integers had they not been compressed
          with the Variable Bit Rate encoding scheme.

       Bytes Saved With VBR
          The  total number of bytes saved in this function by using the Vari-
          able Bit Rate encoding scheme.  The percentage is relative to  #  of
          VBR Expanded Bytes.

SEE ALSO
       /CommandGuide/llvm-dis, /BitCodeFormat

AUTHOR
       Maintained by the LLVM Team (https://llvm.org/).

COPYRIGHT
       2003-2020, LLVM Project

8                                 2020-03-19                LLVM-BCANALYZER(1)

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