Man1 - llvm-bcanalyzer.1

llvm-bcanalyzer - LLVM bitcode analyzer

llvm-bcanalyzer [/options/] [/filename/]

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 interest 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.

-nodetails

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

-dump

Causes llvm-bcanalyzer to dump the bitcode in a human readable format. This format is significantly different from LLVM assembly 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.

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

The following items are always printed by llvm-bcanalyzer. They comprize the summary output.

Bitcode Analysis Of Module

#+begin_quote This just provides the name of the module for which bitcode analysis is being generated.

#+end_quote

Bitcode Version Number

#+begin_quote The bitcode version (not LLVM version) of the file read by the analyzer.

#+end_quote

File Size

#+begin_quote The size, in bytes, of the entire bitcode file.

#+end_quote

Module Bytes

#+begin_quote The size, in bytes, of the module block. Percentage is relative to File Size.

#+end_quote

Function Bytes

#+begin_quote The size, in bytes, of all the function blocks. Percentage is relative to File Size.

#+end_quote

Global Types Bytes

#+begin_quote The size, in bytes, of the Global Types Pool. Percentage is relative to File Size. This is the size of the definitions of all types in the bitcode file.

#+end_quote

Constant Pool Bytes

#+begin_quote The size, in bytes, of the Constant Pool Blocks Percentage is relative to File Size.

#+end_quote

Module Globals Bytes

#+begin_quote Ths size, in bytes, of the Global Variable Definitions and their initializers. Percentage is relative to File Size.

#+end_quote

Instruction List Bytes

#+begin_quote The size, in bytes, of all the instruction lists in all the functions. Percentage is relative to File Size. Note that this value is also included in the Function Bytes.

#+end_quote

Compaction Table Bytes

#+begin_quote The size, in bytes, of all the compaction tables in all the functions. Percentage is relative to File Size. Note that this value is also included in the Function Bytes.

#+end_quote

Symbol Table Bytes

#+begin_quote 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.

#+end_quote

Dependent Libraries Bytes

#+begin_quote The size, in bytes, of the list of dependent libraries in the module. Percentage is relative to File Size. Note that this value is also included in the Module Global Bytes.

#+end_quote

Number Of Bitcode Blocks

#+begin_quote The total number of blocks of any kind in the bitcode file.

#+end_quote

Number Of Functions

#+begin_quote The total number of function definitions in the bitcode file.

#+end_quote

Number Of Types

#+begin_quote The total number of types defined in the Global Types Pool.

#+end_quote

Number Of Constants

#+begin_quote The total number of constants (of any type) defined in the Constant Pool.

#+end_quote

Number Of Basic Blocks

#+begin_quote The total number of basic blocks defined in all functions in the bitcode file.

#+end_quote

Number Of Instructions

#+begin_quote The total number of instructions defined in all functions in the bitcode file.

#+end_quote

Number Of Long Instructions

#+begin_quote 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 arguments.

#+end_quote

Number Of Operands

#+begin_quote The total number of operands used in all instructions in the bitcode file.

#+end_quote

Number Of Compaction Tables

#+begin_quote The total number of compaction tables in all functions in the bitcode file.

#+end_quote

Number Of Symbol Tables

#+begin_quote The total number of symbol tables in all functions in the bitcode file.

#+end_quote

Number Of Dependent Libs

#+begin_quote The total number of dependent libraries found in the bitcode file.

#+end_quote

Total Instruction Size

#+begin_quote The total size of the instructions in all functions in the bitcode file.

#+end_quote

Average Instruction Size

#+begin_quote The average number of bytes per instruction across all functions in the bitcode file. This value is computed by dividing Total Instruction Size by Number Of Instructions.

#+end_quote

Maximum Type Slot Number

#+begin_quote The maximum value used for a type’s slot number. Larger slot number values take more bytes to encode.

#+end_quote

Maximum Value Slot Number

#+begin_quote The maximum value used for a value’s slot number. Larger slot number values take more bytes to encode.

#+end_quote

Bytes Per Value

#+begin_quote The average size of a Value definition (of any type). This is computed by dividing File Size by the total number of values of any type.

#+end_quote

Bytes Per Global

#+begin_quote The average size of a global definition (constants and global variables).

#+end_quote

Bytes Per Function

#+begin_quote The average number of bytes per function definition. This is computed by dividing Function Bytes by Number Of Functions.

#+end_quote

# of VBR 32-bit Integers

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

#+end_quote

# of VBR 64-bit Integers

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

#+end_quote

# of VBR Compressed Bytes

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

#+end_quote

# of VBR Expanded Bytes

#+begin_quote 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.

#+end_quote

Bytes Saved With VBR

#+begin_quote The total number of bytes saved by using the Variable Bit Rate encoding scheme. The percentage is relative to # of VBR Expanded Bytes.

#+end_quote

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

Type

#+begin_quote The type signature of the function.

#+end_quote

Byte Size

#+begin_quote The total number of bytes in the function’s block.

#+end_quote

Basic Blocks

#+begin_quote The number of basic blocks defined by the function.

#+end_quote

Instructions

#+begin_quote The number of instructions defined by the function.

#+end_quote

Long Instructions

#+begin_quote The number of instructions using the long instruction format in the function.

#+end_quote

Operands

#+begin_quote The number of operands used by all instructions in the function.

#+end_quote

Instruction Size

#+begin_quote The number of bytes consumed by instructions in the function.

#+end_quote

Average Instruction Size

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

#+end_quote

Bytes Per Instruction

#+begin_quote 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.

#+end_quote

Number of VBR 32-bit Integers

#+begin_quote The total number of 32-bit integers found in this function (for any use).

#+end_quote

Number of VBR 64-bit Integers

#+begin_quote The total number of 64-bit integers found in this function (for any use).

#+end_quote

Number of VBR Compressed Bytes

#+begin_quote 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.

#+end_quote

Number of VBR Expanded Bytes

#+begin_quote The total number of bytes in this function that would have been consumed by the 32-bit and 64-bit integers had they not been compressed with the Variable Bit Rate encoding scheme.

#+end_quote

Bytes Saved With VBR

#+begin_quote The total number of bytes saved in this function by using the Variable Bit Rate encoding scheme. The percentage is relative to # of VBR Expanded Bytes.

#+end_quote

llvm-dis(1), /BitCodeFormat

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

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