debug_info_test: Run tests based on debug info

debug_info_test calls tests on the given ELF files. When a directory is
supplied, all ELFs will be searched and tested recursively.

BUG=chromium:817648
TEST=debug_info_test /build/kip/usr/lib/debug

Change-Id: Ibcb1ac2de19df9227eb6e242d611ec841d4b589f
Reviewed-on: https://chromium-review.googlesource.com/942465
Commit-Ready: Ting-Yuan Huang <laszio@chromium.org>
Tested-by: Ting-Yuan Huang <laszio@chromium.org>
Reviewed-by: Ting-Yuan Huang <laszio@chromium.org>
Reviewed-by: Yunlian Jiang <yunlian@chromium.org>

6 files changed, 219 insertions, 0 deletions

diff --git a/debug_info_test/check_clang.py b/debug_info_test/check_clang.py
new file mode 100644
index 00000000..a6d056ed
--- /dev/null
+++ b/debug_info_test/check_clang.py
@@ -0,0 +1,26 @@
+# Copyright 2018 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from whitelist import is_whitelisted
+
+def is_built_with_clang(dso_path, producer, comp_path):
+    """Check whether the compile unit is built by clang.
+
+    Args:
+        dso_path: path to the elf/dso
+        producer: DW_AT_producer contains the compiler command line.
+        comp_path: DW_AT_comp_dir + DW_AT_name
+
+    Returns:
+        False if compiled by gcc otherwise True
+    """
+    if is_whitelisted('clang_comp_path', comp_path):
+        return True
+
+    if is_whitelisted('clang_dso_path', dso_path):
+        return True
+
+    if 'clang version' not in producer:
+        return False
+    return True
diff --git a/debug_info_test/check_cus.py b/debug_info_test/check_cus.py
new file mode 100644
index 00000000..88fcf275
--- /dev/null
+++ b/debug_info_test/check_cus.py
@@ -0,0 +1,67 @@
+# Copyright 2018 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import subprocess
+
+import check_clang
+
+cu_checks = [check_clang.is_built_with_clang]
+
+def check_compile_unit(dso_path, producer, comp_path):
+    """check all compiler flags used to build the compile unit.
+
+    Args:
+        dso_path: path to the elf/dso
+        producer: DW_AT_producer contains the compiler command line.
+        comp_path: DW_AT_comp_dir + DW_AT_name
+
+    Returns:
+        A set of failed tests.
+    """
+    failed = set()
+    for c in cu_checks:
+        if not c(dso_path, producer, comp_path):
+            failed.add(c.__module__)
+
+    return failed
+
+def check_compile_units(dso_path):
+    """check all compile units in the given dso.
+
+    Args:
+        dso_path: path to the dso
+    Return:
+        True if everything looks fine otherwise False.
+    """
+
+    failed = set()
+    producer = ''
+    comp_path = ''
+
+    readelf = subprocess.Popen(['readelf', '--debug-dump=info',
+                                '--dwarf-depth=1', dso_path],
+                                stdout=subprocess.PIPE,
+                                stderr=open(os.devnull, 'w'))
+    for l in readelf.stdout:
+        if 'DW_TAG_compile_unit' in l:
+            if producer:
+                failed = failed.union(check_compile_unit(dso_path, producer,
+                                                         comp_path))
+            producer = ''
+            comp_path = ''
+        elif 'DW_AT_producer' in l:
+            producer = l
+        elif 'DW_AT_name' in l:
+            comp_path = os.path.join(comp_path, l.split(':')[-1].strip())
+        elif 'DW_AT_comp_dir' in l:
+            comp_path = os.path.join(l.split(':')[-1].strip(), comp_path)
+    if producer:
+        failed = failed.union(check_compile_unit(dso_path, producer, comp_path))
+
+    if failed:
+        print('%s failed check: %s' % (dso_path, ' '.join(failed)))
+        return False
+
+    return True
diff --git a/debug_info_test/clang_comp_path.whitelist b/debug_info_test/clang_comp_path.whitelist
new file mode 100644
index 00000000..45df0547
--- /dev/null
+++ b/debug_info_test/clang_comp_path.whitelist
@@ -0,0 +1,4 @@
+# These are generally objects linked from system libraries such as glibc
+# and libgcc.
+.*/glibc-.*/
+.*/libgcc/.*
diff --git a/debug_info_test/clang_dso_path.whitelist b/debug_info_test/clang_dso_path.whitelist
new file mode 100644
index 00000000..74f520ea
--- /dev/null
+++ b/debug_info_test/clang_dso_path.whitelist
@@ -0,0 +1,12 @@
+# modules we don't care:
+.*/binutils/.*
+.*/binutils-bin/.*
+.*/libpepflashplayer\.so\.debug
+.*/opt/punybench/bin/.*
+.*/telemetry_dep/.*
+.*/unixbench/.*
+.*/opt/google/containers/android/.*
+.*/libmali\.so.*\.debug
+# todos:
+.*/flashrom_s.debug
+.*/ec_ctl.debug
diff --git a/debug_info_test/debug_info_test.py b/debug_info_test/debug_info_test.py
new file mode 100755
index 00000000..cf3148db
--- /dev/null
+++ b/debug_info_test/debug_info_test.py
@@ -0,0 +1,53 @@
+#!/usr/bin/python
+
+# Copyright 2018 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import subprocess
+import sys
+
+import check_cus
+
+elf_checks = [check_cus.check_compile_units]
+
+def scanelf(root):
+    """find ELFs in root
+
+    Args:
+        root: root dir to start with the search.
+    Returns:
+        Filenames of ELFs in root.
+    """
+    p = subprocess.Popen(['scanelf', '-y', '-B', '-F', '%F', '-R', root],
+                         stdout=subprocess.PIPE)
+    return [l.strip() for l in p.stdout]
+
+def Main(argv):
+    if len(argv) < 2:
+        print('usage: %s [file|dir]')
+        return 1
+
+    files = []
+    cand = argv[1]
+    if os.path.isfile(cand):
+        files = [cand]
+    elif os.path.isdir(cand):
+        files = scanelf(cand)
+    else:
+        print('usage: %s [file|dir]')
+        return 1
+
+    failed = False
+    for f in files:
+        for c in elf_checks:
+            if not c(f):
+                failed = True
+
+    if failed:
+        return 1
+    return 0
+
+if __name__ == '__main__':
+    sys.exit(Main(sys.argv))
diff --git a/debug_info_test/whitelist.py b/debug_info_test/whitelist.py
new file mode 100644
index 00000000..99a457c0
--- /dev/null
+++ b/debug_info_test/whitelist.py
@@ -0,0 +1,57 @@
+# Copyright 2018 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import glob
+import re
+
+# Matching a string of length m in an NFA of size n is O(mn^2), but the
+# performance also depends largely on the implementation. It appears to be fast
+# enough according to the tests.
+#
+# The performance bottleneck of this script is readelf. Unless this becomes
+# slower than readelf, don't waste time here.
+def is_whitelisted(list_name, pattern):
+    """chech whether the given pattern is specified in the whitelist.
+
+    Args:
+        list_name: name of the whitelist
+        pattern: the target string
+    Returns:
+        True if matched otherwise False
+    """
+    return pattern and whitelists[list_name].match(pattern)
+
+def prepare_whitelist(patterns):
+    """Join and compile the re patterns.
+
+    Args:
+        patterns: regex patterns.
+    Return:
+        A compiled re object
+    """
+    return re.compile('|'.join(patterns))
+
+def load_whitelists(dirname):
+    """Load whitelists under dirname.
+
+    A whitelist ends with .whitelist.
+
+    Args:
+        dirname: path to the dir.
+    Returns:
+        A dictionary of 'filename' -> whitelist matcher.
+    """
+    wlist = {}
+    for fn in glob.glob(os.path.join(dirname, '*.whitelist')):
+        key = os.path.splitext(os.path.basename(fn))[0]
+        with open(fn, 'r') as f:
+            patterns = f.read().splitlines()
+            patterns = [l for l in patterns if l[0] != '#']
+            patterns = [l for l in patterns if l != '']
+        wlist[key] = prepare_whitelist(patterns)
+    return wlist
+
+
+whitelists = load_whitelists(os.path.dirname(__file__))