[libc++] Use Python subprocess instead of libc++'s own utilities

[ldionne]

Summary

Once we move off entirely from the legacy testing framework, this will
allow removing a bunch of code.

[EricWF]

libcxx/utils/libcxx/sym_check/util.py

69–70

I believe this needs capture_output=True to work.

Has this been tested?

[EricWF]

libcxx/utils/libcxx/sym_check/util.py

69–70

Oh, and I think it's missing a .decode() call as well.

[ldionne]

libcxx/utils/libcxx/sym_check/util.py

69–70

I did run the check-cxx-abilist target, which should run this unless mistaken.

EDIT: Well, it turns out I was mistaken! This is only called when there *is* a difference in the two ABI lists, and I had only tested with matching ABI lists. Fixed now, thanks for the catch.

[ldionne]

Fix broken sym_diff.

libcxx/utils/libcxx/sym_check/extract.py

 # -*- Python -*- vim: set syntax=python tabstop=4 expandtab cc=80:
 #===----------------------------------------------------------------------===##
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #
 #===----------------------------------------------------------------------===##
 """
 extract - A set of function that extract symbol lists from shared libraries.
 """
 import distutils.spawn
 import os.path
-import sys
 import re
+import subprocess
+import sys
 
-import libcxx.util
 from libcxx.sym_check import util
 
 extract_ignore_names = ['_init', '_fini']
 
 class NMExtractor(object):
     """
     NMExtractor - Extract symbol lists from libraries using nm.
     """
class NMExtractor(object):
 
 
     def extract(self, lib):
         """
         Extract symbols from a library and return the results as a dict of
         parsed symbols.
         """
         cmd = [self.nm_exe] + self.flags + [lib]
-        out, _, exit_code = libcxx.util.executeCommandVerbose(cmd)
-        if exit_code != 0:
-            raise RuntimeError('Failed to run %s on %s' % (self.nm_exe, lib))
+        out = subprocess.check_output(cmd).decode()
         fmt_syms = (self._extract_sym(l)
                     for l in out.splitlines() if l.strip())
         # Cast symbol to string.
         final_syms = (repr(s) for s in fmt_syms if self._want_sym(s))
         # Make unique and sort strings.
         tmp_list = list(sorted(set(final_syms)))
         # Cast string back to symbol.
         return util.read_syms_from_list(tmp_list)
def __init__(self, static_lib):
         self.flags = ['--wide', '--symbols']
 
     def extract(self, lib):
         """
         Extract symbols from a library and return the results as a dict of
         parsed symbols.
         """
         cmd = [self.tool] + self.flags + [lib]
-        out, _, exit_code = libcxx.util.executeCommandVerbose(cmd)
-        if exit_code != 0:
-            raise RuntimeError('Failed to run %s on %s' % (self.nm_exe, lib))
+        out = subprocess.check_output(cmd).decode()
         dyn_syms = self.get_dynsym_table(out)
         return self.process_syms(dyn_syms)
 
     def process_syms(self, sym_list):
         new_syms = []
         for s in sym_list:
             parts = s.split()
             if not parts:

libcxx/utils/libcxx/sym_check/util.py

 #===----------------------------------------------------------------------===##
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #
 #===----------------------------------------------------------------------===##
 
+from pprint import pformat
 import ast
 import distutils.spawn
-import sys
 import re
-import libcxx.util
-from pprint import pformat
+import subprocess
+import sys
 
 
 def read_syms_from_list(slist):
     """
     Read a list of symbols from a list of strings.
     Each string is one symbol.
     """
     return [ast.literal_eval(l) for l in slist]

 
 
 _cppfilt_exe = distutils.spawn.find_executable('c++filt')
 
 
 def demangle_symbol(symbol):
     if _cppfilt_exe is None:
         return symbol
-    out, _, exit_code = libcxx.util.executeCommandVerbose(
-        [_cppfilt_exe], input=symbol)
-    if exit_code != 0:
+    result = subprocess.run([_cppfilt_exe], input=symbol.encode(), capture_output=True)
+    if result.returncode != 0:
         return symbol
-    return out
+    return result.stdout.decode()
 
 
 def is_elf(filename):
     with open(filename, 'rb') as f:
         magic_bytes = f.read(4)
     return magic_bytes == b'\x7fELF'