1 files changed, 68 insertions, 0 deletions
diff --git a/python/mozbuild/mozbuild/configure/check_debug_ranges.py b/python/mozbuild/mozbuild/configure/check_debug_ranges.py
new file mode 100644
index 0000000000..f82624c14f
--- /dev/null
+++ b/python/mozbuild/mozbuild/configure/check_debug_ranges.py
@@ -0,0 +1,68 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# This script returns the number of items for the DW_AT_ranges corresponding
+# to a given compilation unit. This is used as a helper to find a bug in some
+# versions of GNU ld.
+
+import re
+import subprocess
+import sys
+
+
+def get_range_for(compilation_unit, debug_info):
+    """Returns the range offset for a given compilation unit
+    in a given debug_info."""
+    name = ranges = ""
+    search_cu = False
+    for nfo in debug_info.splitlines():
+        if "DW_TAG_compile_unit" in nfo:
+            search_cu = True
+        elif "DW_TAG_" in nfo or not nfo.strip():
+            if name == compilation_unit and ranges != "":
+                return int(ranges, 16)
+            name = ranges = ""
+            search_cu = False
+        if search_cu:
+            if "DW_AT_name" in nfo:
+                name = nfo.rsplit(None, 1)[1]
+            elif "DW_AT_ranges" in nfo:
+                ranges = nfo.rsplit(None, 1)[1]
+    return None
+
+
+def get_range_length(range, debug_ranges):
+    """Returns the number of items in the range starting at the
+    given offset."""
+    length = 0
+    for line in debug_ranges.splitlines():
+        m = re.match("\s*([0-9a-fA-F]+)\s+([0-9a-fA-F]+)\s+([0-9a-fA-F]+)", line)
+        if m and int(m.group(1), 16) == range:
+            length += 1
+    return length
+
+
+def main(bin, compilation_unit):
+    p = subprocess.Popen(
+        ["objdump", "-W", bin],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        universal_newlines=True,
+    )
+    (out, err) = p.communicate()
+    sections = re.split("\n(Contents of the|The section) ", out)
+    debug_info = [s for s in sections if s.startswith(".debug_info")]
+    debug_ranges = [s for s in sections if s.startswith(".debug_ranges")]
+    if not debug_ranges or not debug_info:
+        return 0
+
+    range = get_range_for(compilation_unit, debug_info[0])
+    if range is not None:
+        return get_range_length(range, debug_ranges[0])
+
+    return -1
+
+
+if __name__ == "__main__":
+    print(main(*sys.argv[1:]))