Add executable analaysis tool for floating point checks.

Author: hugueskamba

tools/executable_analysis_tools/elf-float-checker.py

@@ -0,0 +1,168 @@
+#!/usr/bin/env python3
+# Copyright (c) 2019 Arm Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: Apache-2.0
+
+"""Script for checking for floating point symbols in ELF files."""
+
+import argparse
+import logging
+import re
+import subprocess
+import sys
+
+log = logging.getLogger(__name__)
+
+LOG_FORMAT = "%(asctime)s - %(levelname)s - %(message)s"
+FLOATING_POINT_SYMBOL_REGEX = r"__aeabi_(cd.+|cf.+|h2f.+|d.+|f.+|.+2d|.+2f)"
+
+
+class SymbolParser:
+    """Parse the given ELF format file."""
+
+    def get_symbols_from_table(self, symbol_table, symbol_regex):
+        """Get symbols matching a regular expression pattern from a table."""
+        pattern = re.compile(symbol_regex, re.X)
+        matched_symbols = []
+        symbol_table_lines = symbol_table.split("\n")
+        for symbol_table_line in symbol_table_lines:
+            match = pattern.search(symbol_table_line)
+            if match:
+                log.debug("Symbol line: {}".format(symbol_table_line))
+                log.debug("Match found: {}".format(match))
+                matched_symbols.append(match.group(0))
+
+        log.debug("Symbols found:\n'{}'".format(matched_symbols))
+        return matched_symbols
+
+    def get_symbol_table(self, elf_file):
+        """Get the symbol table from an ELF format file."""
+        log.debug(
+            "Get the symbol table for ELF format file '{}'".format(elf_file)
+        )
+        # Command syntax:
+        # `arm-none-eabi-readelf --symbols <elf_file>`
+        cmd = ["arm-none-eabi-readelf", "--symbols", elf_file]
+        try:
+            process = subprocess.run(
+                cmd,
+                check=True,
+                stdin=None,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.STDOUT,
+            )
+        except subprocess.CalledProcessError as error:
+            err_output = error.stdout.decode()
+            msg = (
+                "Getting symbol table for ELF format file '{}' failed,"
+                " error: {}".format(elf_file, err_output)
+            )
+            raise SymbolTableError(msg)
+
+        symbol_table = process.stdout.decode()
+        log.debug("Symbol table:\n{}\n".format(symbol_table))
+
+        return symbol_table
+
+
+class SymbolTableError(Exception):
+    """An exception for a failure to obtain a symbol table."""
+
+
+class ArgumentParserWithDefaultHelp(argparse.ArgumentParser):
+    """Subclass that always shows the help message on invalid arguments."""
+
+    def error(self, message):
+        """Error handler."""
+        sys.stderr.write("error: {}\n".format(message))
+        self.print_help()
+
+
+def set_log_verbosity(increase_verbosity):
+    """Set the verbosity of the log output."""
+    log_level = logging.DEBUG if increase_verbosity else logging.INFO
+
+    log.setLevel(log_level)
+    logging.basicConfig(level=log_level, format=LOG_FORMAT)
+
+
+def check_float_symbols(elf_file):
+    """Check for floating point symbols in ELF format file.
+
+    Return the floating point symbols found.
+    """
+    parser = SymbolParser()
+    symbol_table = parser.get_symbol_table(elf_file)
+
+    float_symbols = parser.get_symbols_from_table(
+        symbol_table, FLOATING_POINT_SYMBOL_REGEX
+    )
+
+    return float_symbols
+
+
+def check_action(args):
+    """Entry point for checking the ELF file."""
+    float_symbols = check_float_symbols(args.elf_file)
+    if float_symbols:
+        print("Found float symbols:")
+        for float_symbol in float_symbols:
+            print(float_symbol)
+    else:
+        print("No float symbols found.")
+
+
+def parse_args():
+    """Parse the command line args."""
+    parser = ArgumentParserWithDefaultHelp(
+        description="ELF floats checker",
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+    )
+
+    parser.add_argument(
+        "elf_file",
+        type=str,
+        help=(
+            "the Executable and Linkable Format (ELF) file to check"
+            " for floating point instruction inclusion."
+        ),
+    )
+
+    parser.add_argument(
+        "-v",
+        "--verbose",
+        action="store_true",
+        help="increase verbosity of status information.",
+    )
+
+    parser.set_defaults(func=check_action)
+
+    args_namespace = parser.parse_args()
+
+    # We want to fail gracefully, with a consistent
+    # help message, in the no argument case.
+    # So here's an obligatory hasattr hack.
+    if not hasattr(args_namespace, "func"):
+        parser.error("No arguments given!")
+    else:
+        return args_namespace
+
+
+def run_elf_floats_checker():
+    """Application main algorithm."""
+    args = parse_args()
+
+    set_log_verbosity(args.verbose)
+
+    log.debug("Starting elf-floats-checker")
+    log.debug("Command line arguments:{}".format(args))
+
+    args.func(args)
+
+
+if __name__ == "__main__":
+    """Run elf-floats-checker."""
+    try:
+        run_elf_floats_checker()
+    except Exception as error:
+        print(error)