cvw/bin/analyze_riscv_elf.py
2025-04-08 17:17:25 -05:00

83 lines
2.9 KiB
Python
Executable file

#!/usr/bin/env python3
###########################################
## analyze_riscv_elf.py
##
## Written: james.stine@okstate.edu
## Created: April 7, 2025
##
## Purpose: Analyze a RISC-V ELF file and report which instructions are used,
## along with their frequency. The script disassembles the ELF using
## riscv64-unknown-elf-objdump, filters real instructions (excluding
## pseudo-ops and section headers), and displays a histogram of
## instruction use.
##
## A component of the CORE-V-WALLY configurable RISC-V project.
## https://github.com/openhwgroup/cvw
##
## Copyright (C) 2021-25 Harvey Mudd College & Oklahoma State University
##
## SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1
##
## Licensed under the Solderpad Hardware License v 2.1 (the “License”); you may not use this file
## except in compliance with the License, or, at your option, the Apache License version 2.0. You
## may obtain a copy of the License at
##
## https:##solderpad.org/licenses/SHL-2.1/
##
## Unless required by applicable law or agreed to in writing, any work distributed under the
## License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
## either express or implied. See the License for the specific language governing permissions
## and limitations under the License.
################################################################################################
import re
import subprocess
import sys
from collections import Counter
def disassemble_elf(elf_path):
try:
result = subprocess.run(
["riscv64-unknown-elf-objdump", "-d", "-M", "no-aliases", elf_path],
capture_output=True,
text=True,
check=True
)
return result.stdout
except subprocess.CalledProcessError as e:
print(f"Error running objdump: {e.stderr}")
sys.exit(1)
def extract_instructions(disassembly):
instructions = []
for line in disassembly.splitlines():
# Match instruction lines only: address: machine-code instruction [operands...]
match = re.match(r'^\s*[0-9a-f]+:\s+([0-9a-f]{8}|\s{8})\s+(\S+)', line)
if match:
instr = match.group(2)
instructions.append(instr)
return instructions
def main():
if len(sys.argv) != 2:
print("Usage: python3 analyze_riscv_elf.py <file.elf>")
sys.exit(1)
elf_path = sys.argv[1]
disassembly = disassemble_elf(elf_path)
instructions = extract_instructions(disassembly)
counter = Counter(instructions)
print(f"\nInstruction usage in {elf_path}:\n")
if not counter:
print("No instructions found (did you use the correct target ELF file?)")
else:
for instr, count in counter.most_common():
count_str = f"{count:,}" # Add comma as thousands separator
print(f"{instr:<10} {count_str}")
if __name__ == "__main__":
main()