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1 #
2 # Copyright (c) 2001 - 2017 The SCons Foundation
3 #
4 # Permission is hereby granted, free of charge, to any person obtaining
5 # a copy of this software and associated documentation files (the
6 # "Software"), to deal in the Software without restriction, including
7 # without limitation the rights to use, copy, modify, merge, publish,
8 # distribute, sublicense, and/or sell copies of the Software, and to
9 # permit persons to whom the Software is furnished to do so, subject to
10 # the following conditions:
11 #
12 # The above copyright notice and this permission notice shall be included
13 # in all copies or substantial portions of the Software.
14 #
15 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
16 # KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
17 # WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
19 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
20 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
21 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 #
23
24 __revision__ = "src/engine/SCons/cpp.py 74b2c53bc42290e911b334a6b44f187da698a668 2017/11/14 13:16:53 bdbaddog"
25
26 __doc__ = """
27 SCons C Pre-Processor module
28 """
29 import SCons.compat
30
31 import os
32 import re
33
34 #
35 # First "subsystem" of regular expressions that we set up:
36 #
37 # Stuff to turn the C preprocessor directives in a file's contents into
38 # a list of tuples that we can process easily.
39 #
40
41 # A table of regular expressions that fetch the arguments from the rest of
42 # a C preprocessor line. Different directives have different arguments
43 # that we want to fetch, using the regular expressions to which the lists
44 # of preprocessor directives map.
45 cpp_lines_dict = {
46 # Fetch the rest of a #if/#elif/#ifdef/#ifndef as one argument,
47 # separated from the keyword by white space.
48 ('if', 'elif', 'ifdef', 'ifndef',)
49 : '\s+(.+)',
50
51 # Fetch the rest of a #import/#include/#include_next line as one
52 # argument, with white space optional.
53 ('import', 'include', 'include_next',)
54 : '\s*(.+)',
55
56 # We don't care what comes after a #else or #endif line.
57 ('else', 'endif',) : '',
58
59 # Fetch three arguments from a #define line:
60 # 1) The #defined keyword.
61 # 2) The optional parentheses and arguments (if it's a function-like
62 # macro, '' if it's not).
63 # 3) The expansion value.
64 ('define',) : '\s+([_A-Za-z][_A-Za-z0-9_]*)(\([^)]*\))?\s*(.*)',
65
66 # Fetch the #undefed keyword from a #undef line.
67 ('undef',) : '\s+([_A-Za-z][A-Za-z0-9_]*)',
68 }
69
70 # Create a table that maps each individual C preprocessor directive to
71 # the corresponding compiled regular expression that fetches the arguments
72 # we care about.
73 Table = {}
74 for op_list, expr in cpp_lines_dict.items():
75 e = re.compile(expr)
76 for op in op_list:
77 Table[op] = e
78 del e
79 del op
80 del op_list
81
82 # Create a list of the expressions we'll use to match all of the
83 # preprocessor directives. These are the same as the directives
84 # themselves *except* that we must use a negative lookahead assertion
85 # when matching "if" so it doesn't match the "if" in "ifdef."
86 override = {
87 'if' : 'if(?!def)',
88 }
89 l = [override.get(x, x) for x in list(Table.keys())]
90
91
92 # Turn the list of expressions into one big honkin' regular expression
93 # that will match all the preprocessor lines at once. This will return
94 # a list of tuples, one for each preprocessor line. The preprocessor
95 # directive will be the first element in each tuple, and the rest of
96 # the line will be the second element.
97 e = '^\s*#\s*(' + '|'.join(l) + ')(.*)$'
98
99 # And last but not least, compile the expression.
100 CPP_Expression = re.compile(e, re.M)
101
102
103
104
105 #
106 # Second "subsystem" of regular expressions that we set up:
107 #
108 # Stuff to translate a C preprocessor expression (as found on a #if or
109 # #elif line) into an equivalent Python expression that we can eval().
110 #
111
112 # A dictionary that maps the C representation of Boolean operators
113 # to their Python equivalents.
114 CPP_to_Python_Ops_Dict = {
115 '!' : ' not ',
116 '!=' : ' != ',
117 '&&' : ' and ',
118 '||' : ' or ',
119 '?' : ' and ',
120 ':' : ' or ',
121 '\r' : '',
122 }
123
124 CPP_to_Python_Ops_Sub = lambda m: CPP_to_Python_Ops_Dict[m.group(0)]
125
126 # We have to sort the keys by length so that longer expressions
127 # come *before* shorter expressions--in particular, "!=" must
128 # come before "!" in the alternation. Without this, the Python
129 # re module, as late as version 2.2.2, empirically matches the
130 # "!" in "!=" first, instead of finding the longest match.
131 # What's up with that?
132 l = sorted(list(CPP_to_Python_Ops_Dict.keys()), key=lambda a: len(a), reverse=True)
133
134 # Turn the list of keys into one regular expression that will allow us
135 # to substitute all of the operators at once.
136 expr = '|'.join(map(re.escape, l))
137
138 # ...and compile the expression.
139 CPP_to_Python_Ops_Expression = re.compile(expr)
140
141 # A separate list of expressions to be evaluated and substituted
142 # sequentially, not all at once.
143 CPP_to_Python_Eval_List = [
144 ['defined\s+(\w+)', '"\\1" in __dict__'],
145 ['defined\s*\((\w+)\)', '"\\1" in __dict__'],
146 ['/\*.*\*/', ''],
147 ['/\*.*', ''],
148 ['//.*', ''],
149 ['(0x[0-9A-Fa-f]*)[UL]+', '\\1'],
150 ]
151
152 # Replace the string representations of the regular expressions in the
153 # list with compiled versions.
154 for l in CPP_to_Python_Eval_List:
155 l[0] = re.compile(l[0])
156
157 # Wrap up all of the above into a handy function.
159 """
160 Converts a C pre-processor expression into an equivalent
161 Python expression that can be evaluated.
162 """
163 s = CPP_to_Python_Ops_Expression.sub(CPP_to_Python_Ops_Sub, s)
164 for expr, repl in CPP_to_Python_Eval_List:
165 s = expr.sub(repl, s)
166 return s
167
168
169
170 del expr
171 del l
172 del override
173
174
175
177 """
178 Handles delayed evaluation of a #define function call.
179 """
181 """
182 Squirrels away the arguments and expansion value of a #define
183 macro function for later evaluation when we must actually expand
184 a value that uses it.
185 """
186 self.name = name
187 self.args = function_arg_separator.split(args)
188 try:
189 expansion = expansion.split('##')
190 except AttributeError:
191 pass
192 self.expansion = expansion
194 """
195 Evaluates the expansion of a #define macro function called
196 with the specified values.
197 """
198 if len(self.args) != len(values):
199 raise ValueError("Incorrect number of arguments to `%s'" % self.name)
200 # Create a dictionary that maps the macro arguments to the
201 # corresponding values in this "call." We'll use this when we
202 # eval() the expansion so that arguments will get expanded to
203 # the right values.
204 locals = {}
205 for k, v in zip(self.args, values):
206 locals[k] = v
207
208 parts = []
209 for s in self.expansion:
210 if not s in self.args:
211 s = repr(s)
212 parts.append(s)
213 statement = ' + '.join(parts)
214
215 return eval(statement, globals(), locals)
216
217
218
219 # Find line continuations.
220 line_continuations = re.compile('\\\\\r?\n')
221
222 # Search for a "function call" macro on an expansion. Returns the
223 # two-tuple of the "function" name itself, and a string containing the
224 # arguments within the call parentheses.
225 function_name = re.compile('(\S+)\(([^)]*)\)')
226
227 # Split a string containing comma-separated function call arguments into
228 # the separate arguments.
229 function_arg_separator = re.compile(',\s*')
230
231
232
234 """
235 The main workhorse class for handling C pre-processing.
236 """
238 global Table
239
240 cpppath = tuple(cpppath)
241
242 self.searchpath = {
243 '"' : (current,) + cpppath,
244 '<' : cpppath + (current,),
245 }
246
247 # Initialize our C preprocessor namespace for tracking the
248 # values of #defined keywords. We use this namespace to look
249 # for keywords on #ifdef/#ifndef lines, and to eval() the
250 # expressions on #if/#elif lines (after massaging them from C to
251 # Python).
252 self.cpp_namespace = dict.copy()
253 self.cpp_namespace['__dict__'] = self.cpp_namespace
254
255 if all:
256 self.do_include = self.all_include
257
258 # For efficiency, a dispatch table maps each C preprocessor
259 # directive (#if, #define, etc.) to the method that should be
260 # called when we see it. We accomodate state changes (#if,
261 # #ifdef, #ifndef) by pushing the current dispatch table on a
262 # stack and changing what method gets called for each relevant
263 # directive we might see next at this level (#else, #elif).
264 # #endif will simply pop the stack.
265 d = {
266 'scons_current_file' : self.scons_current_file
267 }
268 for op in list(Table.keys()):
269 d[op] = getattr(self, 'do_' + op)
270 self.default_table = d
271
272 # Controlling methods.
273
275 """
276 Turns the contents of a file into a list of easily-processed
277 tuples describing the CPP lines in the file.
278
279 The first element of each tuple is the line's preprocessor
280 directive (#if, #include, #define, etc., minus the initial '#').
281 The remaining elements are specific to the type of directive, as
282 pulled apart by the regular expression.
283 """
284 global CPP_Expression, Table
285 contents = line_continuations.sub('', contents)
286 cpp_tuples = CPP_Expression.findall(contents)
287 return [(m[0],) + Table[m[0]].match(m[1]).groups() for m in cpp_tuples]
288
290 """
291 Pre-processes a file.
292
293 This is the main public entry point.
294 """
295 self.current_file = file
296 return self.process_contents(self.read_file(file), file)
297
299 """
300 Pre-processes a file contents.
301
302 This is the main internal entry point.
303 """
304 self.stack = []
305 self.dispatch_table = self.default_table.copy()
306 self.current_file = fname
307 self.tuples = self.tupleize(contents)
308
309 self.initialize_result(fname)
310 while self.tuples:
311 t = self.tuples.pop(0)
312 # Uncomment to see the list of tuples being processed (e.g.,
313 # to validate the CPP lines are being translated correctly).
314 #print(t)
315 self.dispatch_table[t[0]](t)
316 return self.finalize_result(fname)
317
318 # Dispatch table stack manipulation methods.
319
321 """
322 Pushes the current dispatch table on the stack and re-initializes
323 the current dispatch table to the default.
324 """
325 self.stack.append(self.dispatch_table)
326 self.dispatch_table = self.default_table.copy()
327
329 """
330 Pops the previous dispatch table off the stack and makes it the
331 current one.
332 """
333 try: self.dispatch_table = self.stack.pop()
334 except IndexError: pass
335
336 # Utility methods.
337
339 """
340 Null method for when we explicitly want the action for a
341 specific preprocessor directive to do nothing.
342 """
343 pass
344
347
349 """
350 Evaluates a C preprocessor expression.
351
352 This is done by converting it to a Python equivalent and
353 eval()ing it in the C preprocessor namespace we use to
354 track #define values.
355 """
356 t = CPP_to_Python(' '.join(t[1:]))
357 try: return eval(t, self.cpp_namespace)
358 except (NameError, TypeError): return 0
359
361 self.result = [fname]
362
364 return self.result[1:]
365
367 """
368 Finds the #include file for a given preprocessor tuple.
369 """
370 fname = t[2]
371 for d in self.searchpath[t[1]]:
372 if d == os.curdir:
373 f = fname
374 else:
375 f = os.path.join(d, fname)
376 if os.path.isfile(f):
377 return f
378 return None
379
383
384 # Start and stop processing include lines.
385
387 """
388 Causes the PreProcessor object to start processing #import,
389 #include and #include_next lines.
390
391 This method will be called when a #if, #ifdef, #ifndef or #elif
392 evaluates True, or when we reach the #else in a #if, #ifdef,
393 #ifndef or #elif block where a condition already evaluated
394 False.
395
396 """
397 d = self.dispatch_table
398 p = self.stack[-1] if self.stack else self.default_table
399
400 for k in ('import', 'include', 'include_next'):
401 d[k] = p[k]
402
404 """
405 Causes the PreProcessor object to stop processing #import,
406 #include and #include_next lines.
407
408 This method will be called when a #if, #ifdef, #ifndef or #elif
409 evaluates False, or when we reach the #else in a #if, #ifdef,
410 #ifndef or #elif block where a condition already evaluated True.
411 """
412 d = self.dispatch_table
413 d['import'] = self.do_nothing
414 d['include'] = self.do_nothing
415 d['include_next'] = self.do_nothing
416
417 # Default methods for handling all of the preprocessor directives.
418 # (Note that what actually gets called for a given directive at any
419 # point in time is really controlled by the dispatch_table.)
420
422 """
423 Common logic for evaluating the conditions on #if, #ifdef and
424 #ifndef lines.
425 """
426 self.save()
427 d = self.dispatch_table
428 if condition:
429 self.start_handling_includes()
430 d['elif'] = self.stop_handling_includes
431 d['else'] = self.stop_handling_includes
432 else:
433 self.stop_handling_includes()
434 d['elif'] = self.do_elif
435 d['else'] = self.start_handling_includes
436
438 """
439 Default handling of a #ifdef line.
440 """
441 self._do_if_else_condition(t[1] in self.cpp_namespace)
442
444 """
445 Default handling of a #ifndef line.
446 """
447 self._do_if_else_condition(t[1] not in self.cpp_namespace)
448
450 """
451 Default handling of a #if line.
452 """
453 self._do_if_else_condition(self.eval_expression(t))
454
456 """
457 Default handling of a #elif line.
458 """
459 d = self.dispatch_table
460 if self.eval_expression(t):
461 self.start_handling_includes()
462 d['elif'] = self.stop_handling_includes
463 d['else'] = self.stop_handling_includes
464
470
476
478 """
479 Default handling of a #define line.
480 """
481 _, name, args, expansion = t
482 try:
483 expansion = int(expansion)
484 except (TypeError, ValueError):
485 pass
486 if args:
487 evaluator = FunctionEvaluator(name, args[1:-1], expansion)
488 self.cpp_namespace[name] = evaluator
489 else:
490 self.cpp_namespace[name] = expansion
491
493 """
494 Default handling of a #undef line.
495 """
496 try: del self.cpp_namespace[t[1]]
497 except KeyError: pass
498
500 """
501 Default handling of a #import line.
502 """
503 # XXX finish this -- maybe borrow/share logic from do_include()...?
504 pass
505
507 """
508 Default handling of a #include line.
509 """
510 t = self.resolve_include(t)
511 include_file = self.find_include_file(t)
512 if include_file:
513 #print("include_file =", include_file)
514 self.result.append(include_file)
515 contents = self.read_file(include_file)
516 new_tuples = [('scons_current_file', include_file)] + \
517 self.tupleize(contents) + \
518 [('scons_current_file', self.current_file)]
519 self.tuples[:] = new_tuples + self.tuples
520
521 # Date: Tue, 22 Nov 2005 20:26:09 -0500
522 # From: Stefan Seefeld <seefeld@sympatico.ca>
523 #
524 # By the way, #include_next is not the same as #include. The difference
525 # being that #include_next starts its search in the path following the
526 # path that let to the including file. In other words, if your system
527 # include paths are ['/foo', '/bar'], and you are looking at a header
528 # '/foo/baz.h', it might issue an '#include_next <baz.h>' which would
529 # correctly resolve to '/bar/baz.h' (if that exists), but *not* see
530 # '/foo/baz.h' again. See http://www.delorie.com/gnu/docs/gcc/cpp_11.html
531 # for more reasoning.
532 #
533 # I have no idea in what context 'import' might be used.
534
535 # XXX is #include_next really the same as #include ?
536 do_include_next = do_include
537
538 # Utility methods for handling resolution of include files.
539
541 """Resolve a tuple-ized #include line.
542
543 This handles recursive expansion of values without "" or <>
544 surrounding the name until an initial " or < is found, to handle
545
546 #include FILE
547
548 where FILE is a #define somewhere else."""
549
550 s = t[1]
551 while not s[0] in '<"':
552 #print("s =", s)
553 try:
554 s = self.cpp_namespace[s]
555 except KeyError:
556 m = function_name.search(s)
557 s = self.cpp_namespace[m.group(1)]
558 if callable(s):
559 args = function_arg_separator.split(m.group(2))
560 s = s(*args)
561 if not s:
562 return None
563 return (t[0], s[0], s[1:-1])
564
569
571 """A preprocessor that ignores all #if/#elif/#else/#endif directives
572 and just reports back *all* of the #include files (like the classic
573 SCons scanner did).
574
575 This is functionally equivalent to using a regular expression to
576 find all of the #include lines, only slower. It exists mainly as
577 an example of how the main PreProcessor class can be sub-classed
578 to tailor its behavior.
579 """
581 PreProcessor.__init__(self, *args, **kw)
582 d = self.default_table
583 for func in ['if', 'elif', 'else', 'endif', 'ifdef', 'ifndef']:
584 d[func] = d[func] = self.do_nothing
585
586 del __revision__
587
588 # Local Variables:
589 # tab-width:4
590 # indent-tabs-mode:nil
591 # End:
592 # vim: set expandtab tabstop=4 shiftwidth=4:
593
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