Embed swig version into lldb.py in a different way

Summary:
Instead of doing string chopping on the resulting python file, get swig
to output the version for us. The two things which make slightly
non-trivial are:
- in order to get swig to expand SWIG_VERSION for us, we cannot use
  %pythoncode directly, but we have to go through an intermediate macro.
- SWIG_VERSION is a hex number, but it's components are supposed to be
  interpreted decimally, so there is a bit of integer magic needed to
  get the right number to come out.

I've tested that this approach works both with the latest (3.0.12) and
oldest (1.3.40) supported swig.

Reviewers: zturner, jingham, serge-sans-paille

Subscribers: jdoerfert, lldb-commits

Differential Revision: https://reviews.llvm.org/D58172

llvm-svn: 354104

lldb/scripts/Python/modify-python-lldb.py

@@ -44,11 +44,6 @@ else:
 
 # print "output_name is '" + output_name + "'"
 
-#
-# Version string
-#
-version_line = "swig_version = %s"
-
 #
 # Residues to be removed.
 #
@@ -338,7 +333,6 @@ init_pattern = re.compile("^    def __init__\(self.*\):")
 isvalid_pattern = re.compile("^    def IsValid\(")
 
 # These define the states of our finite state machine.
-EXPECTING_VERSION = 0
 NORMAL = 1
 DEFINING_ITERATOR = 2
 DEFINING_EQUALITY = 4
@@ -364,9 +358,8 @@ lldb_iter_defined = False
 # The FSM, in all possible states, also checks the current input for IsValid()
 # definition, and inserts a __nonzero__() method definition to implement truth
 # value testing and the built-in operation bool().
-state = EXPECTING_VERSION
+state = NORMAL
 
-swig_version_tuple = None
 for line in content.splitlines():
     # Handle the state transition into CLEANUP_DOCSTRING state as it is possible
     # to enter this state from either NORMAL or DEFINING_ITERATOR/EQUALITY.
@@ -383,20 +376,6 @@ for line in content.splitlines():
         else:
             state |= CLEANUP_DOCSTRING
 
-    if state == EXPECTING_VERSION:
-        # We haven't read the version yet, read it now.
-        if swig_version_tuple is None:
-            match = version_pattern.search(line)
-            if match:
-                v = match.group(1)
-                swig_version_tuple = tuple(map(int, (v.split("."))))
-        elif not line.startswith('#'):
-            # This is the first non-comment line after the header.  Inject the
-            # version
-            new_line = version_line % str(swig_version_tuple)
-            new_content.add_line(new_line)
-            state = NORMAL
-
     if state == NORMAL:
         match = class_pattern.search(line)
         # Inserts lldb_helpers and the lldb_iter() definition before the first