Add script to extract all valid PCs of ELFs

extract_pc.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+
+""" Extract the list of program counters (PC) at which an instruction can be
+found in the .text section of an ELF object. """
+
+
+import argparse
+import os
+import subprocess
+import re
+import copy
+from shared_python import elf_so_deps, is_newer
+
+
+def generate_pc_list(elf, out_path):
+    ''' Generate the list of valid program counters for the ELF object `elf`,
+    and save it to `out_path`
+    
+    out_path is a binary file, each 8B chunk being a little-endian PC '''
+
+    if is_newer(out_path, elf):
+        return
+
+    with open(out_path, 'wb') as out_handle:
+        objdump_out = subprocess.check_output(
+            ['objdump', '-d', elf]).decode('utf-8')
+        lines = objdump_out.split('\n')
+
+        instr_line_re = re.compile(
+            r'^([0-9a-fA-F]+):\s+(?:[0-9a-fA-F]{2} )+')
+
+        for line in lines:
+            line = line.strip()
+            matched = instr_line_re.match(line)
+            if matched:
+                pc = int(matched.group(1), 0x10)
+                pc_bytes = pc.to_bytes(8, byteorder='little', signed=False)
+                out_handle.write(pc_bytes)
+
+
+def process_args():
+    ''' Process `sys.argv` arguments '''
+
+    parser = argparse.ArgumentParser(
+        description=('Extract the list of program counters (PC) at which an '
+                     'instruction can be found in the .text section of an ELF '
+                     'object.')
+    )
+
+    parser.add_argument('--deps', action='store_true',
+                        help=("Also process the shared objects this object "
+                              "depends on"))
+    parser.add_argument('-o', '--output', required=True,
+                        help=("output directory in which the produced files "
+                              "will be stored"))
+    parser.add_argument('object', nargs='+',
+                        help="The ELF object(s) to process")
+    return parser.parse_args()
+
+
+def main():
+    args = process_args()
+
+    objs_list = copy.copy(args.object)
+    if args.deps:
+        for obj in args.object:
+            objs_list += elf_so_deps(obj)
+
+    for obj in objs_list:
+        basename = os.path.basename(obj)
+        print('> {}…'.format(basename))
+        out_path = os.path.join(args.output,
+                                basename + '.pc_list')
+        generate_pc_list(obj, out_path)
+
+
+if __name__ == '__main__':
+    main()

tests/.gitignore

@@ -1 +1,2 @@
 *.bin
+pc_list.*