xref: /openbmc/qemu/scripts/decodetree.py (revision c017386f28c03a03b8f14444f8671d3d8f7180fe)
1#!/usr/bin/env python3
2# Copyright (c) 2018 Linaro Limited
3#
4# This library is free software; you can redistribute it and/or
5# modify it under the terms of the GNU Lesser General Public
6# License as published by the Free Software Foundation; either
7# version 2.1 of the License, or (at your option) any later version.
8#
9# This library is distributed in the hope that it will be useful,
10# but WITHOUT ANY WARRANTY; without even the implied warranty of
11# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12# Lesser General Public License for more details.
13#
14# You should have received a copy of the GNU Lesser General Public
15# License along with this library; if not, see <http://www.gnu.org/licenses/>.
16#
17
18#
19# Generate a decoding tree from a specification file.
20# See the syntax and semantics in docs/devel/decodetree.rst.
21#
22
23import io
24import os
25import re
26import sys
27import getopt
28
29insnwidth = 32
30bitop_width = 32
31insnmask = 0xffffffff
32variablewidth = False
33fields = {}
34arguments = {}
35formats = {}
36allpatterns = []
37anyextern = False
38testforerror = False
39
40translate_prefix = 'trans'
41translate_scope = 'static '
42input_file = ''
43output_file = None
44output_fd = None
45output_null = False
46insntype = 'uint32_t'
47decode_function = 'decode'
48
49# An identifier for C.
50re_C_ident = '[a-zA-Z][a-zA-Z0-9_]*'
51
52# Identifiers for Arguments, Fields, Formats and Patterns.
53re_arg_ident = '&[a-zA-Z0-9_]*'
54re_fld_ident = '%[a-zA-Z0-9_]*'
55re_fmt_ident = '@[a-zA-Z0-9_]*'
56re_pat_ident = '[a-zA-Z0-9_]*'
57
58# Local implementation of a topological sort. We use the same API that
59# the Python graphlib does, so that when QEMU moves forward to a
60# baseline of Python 3.9 or newer this code can all be dropped and
61# replaced with:
62#    from graphlib import TopologicalSorter, CycleError
63#
64# https://docs.python.org/3.9/library/graphlib.html#graphlib.TopologicalSorter
65#
66# We only implement the parts of TopologicalSorter we care about:
67#  ts = TopologicalSorter(graph=None)
68#    create the sorter. graph is a dictionary whose keys are
69#    nodes and whose values are lists of the predecessors of that node.
70#    (That is, if graph contains "A" -> ["B", "C"] then we must output
71#    B and C before A.)
72#  ts.static_order()
73#    returns a list of all the nodes in sorted order, or raises CycleError
74#  CycleError
75#    exception raised if there are cycles in the graph. The second
76#    element in the args attribute is a list of nodes which form a
77#    cycle; the first and last element are the same, eg [a, b, c, a]
78#    (Our implementation doesn't give the order correctly.)
79#
80# For our purposes we can assume that the data set is always small
81# (typically 10 nodes or less, actual links in the graph very rare),
82# so we don't need to worry about efficiency of implementation.
83#
84# The core of this implementation is from
85# https://code.activestate.com/recipes/578272-topological-sort/
86# (but updated to Python 3), and is under the MIT license.
87
88class CycleError(ValueError):
89    """Subclass of ValueError raised if cycles exist in the graph"""
90    pass
91
92class TopologicalSorter:
93    """Topologically sort a graph"""
94    def __init__(self, graph=None):
95        self.graph = graph
96
97    def static_order(self):
98        # We do the sort right here, unlike the stdlib version
99        from functools import reduce
100        data = {}
101        r = []
102
103        if not self.graph:
104            return []
105
106        # This code wants the values in the dict to be specifically sets
107        for k, v in self.graph.items():
108            data[k] = set(v)
109
110        # Find all items that don't depend on anything.
111        extra_items_in_deps = (reduce(set.union, data.values())
112                               - set(data.keys()))
113        # Add empty dependencies where needed
114        data.update({item:{} for item in extra_items_in_deps})
115        while True:
116            ordered = set(item for item, dep in data.items() if not dep)
117            if not ordered:
118                break
119            r.extend(ordered)
120            data = {item: (dep - ordered)
121                    for item, dep in data.items()
122                        if item not in ordered}
123        if data:
124            # This doesn't give as nice results as the stdlib, which
125            # gives you the cycle by listing the nodes in order. Here
126            # we only know the nodes in the cycle but not their order.
127            raise CycleError(f'nodes are in a cycle', list(data.keys()))
128
129        return r
130# end TopologicalSorter
131
132def error_with_file(file, lineno, *args):
133    """Print an error message from file:line and args and exit."""
134    global output_file
135    global output_fd
136
137    # For the test suite expected-errors case, don't print the
138    # string "error: ", so they don't turn up as false positives
139    # if you grep the meson logs for strings like that.
140    end = 'error: ' if not testforerror else 'detected: '
141    prefix = ''
142    if file:
143        prefix += f'{file}:'
144    if lineno:
145        prefix += f'{lineno}:'
146    if prefix:
147        prefix += ' '
148    print(prefix, end=end, file=sys.stderr)
149    print(*args, file=sys.stderr)
150
151    if output_file and output_fd:
152        output_fd.close()
153        os.remove(output_file)
154    exit(0 if testforerror else 1)
155# end error_with_file
156
157
158def error(lineno, *args):
159    error_with_file(input_file, lineno, *args)
160# end error
161
162
163def output(*args):
164    global output_fd
165    for a in args:
166        output_fd.write(a)
167
168
169def output_autogen():
170    output('/* This file is autogenerated by scripts/decodetree.py.  */\n\n')
171
172
173def str_indent(c):
174    """Return a string with C spaces"""
175    return ' ' * c
176
177
178def str_fields(fields):
179    """Return a string uniquely identifying FIELDS"""
180    r = ''
181    for n in sorted(fields.keys()):
182        r += '_' + n
183    return r[1:]
184
185
186def whex(val):
187    """Return a hex string for val padded for insnwidth"""
188    global insnwidth
189    return f'0x{val:0{insnwidth // 4}x}'
190
191
192def whexC(val):
193    """Return a hex string for val padded for insnwidth,
194       and with the proper suffix for a C constant."""
195    suffix = ''
196    if val >= 0x100000000:
197        suffix = 'ull'
198    elif val >= 0x80000000:
199        suffix = 'u'
200    return whex(val) + suffix
201
202
203def str_match_bits(bits, mask):
204    """Return a string pretty-printing BITS/MASK"""
205    global insnwidth
206
207    i = 1 << (insnwidth - 1)
208    space = 0x01010100
209    r = ''
210    while i != 0:
211        if i & mask:
212            if i & bits:
213                r += '1'
214            else:
215                r += '0'
216        else:
217            r += '.'
218        if i & space:
219            r += ' '
220        i >>= 1
221    return r
222
223
224def is_pow2(x):
225    """Return true iff X is equal to a power of 2."""
226    return (x & (x - 1)) == 0
227
228
229def ctz(x):
230    """Return the number of times 2 factors into X."""
231    assert x != 0
232    r = 0
233    while ((x >> r) & 1) == 0:
234        r += 1
235    return r
236
237
238def is_contiguous(bits):
239    if bits == 0:
240        return -1
241    shift = ctz(bits)
242    if is_pow2((bits >> shift) + 1):
243        return shift
244    else:
245        return -1
246
247
248def eq_fields_for_args(flds_a, arg):
249    if len(flds_a) != len(arg.fields):
250        return False
251    # Only allow inference on default types
252    for t in arg.types:
253        if t != 'int':
254            return False
255    for k, a in flds_a.items():
256        if k not in arg.fields:
257            return False
258    return True
259
260
261def eq_fields_for_fmts(flds_a, flds_b):
262    if len(flds_a) != len(flds_b):
263        return False
264    for k, a in flds_a.items():
265        if k not in flds_b:
266            return False
267        b = flds_b[k]
268        if a.__class__ != b.__class__ or a != b:
269            return False
270    return True
271
272
273class Field:
274    """Class representing a simple instruction field"""
275    def __init__(self, sign, pos, len):
276        self.sign = sign
277        self.pos = pos
278        self.len = len
279        self.mask = ((1 << len) - 1) << pos
280
281    def __str__(self):
282        if self.sign:
283            s = 's'
284        else:
285            s = ''
286        return str(self.pos) + ':' + s + str(self.len)
287
288    def str_extract(self, lvalue_formatter):
289        global bitop_width
290        s = 's' if self.sign else ''
291        return f'{s}extract{bitop_width}(insn, {self.pos}, {self.len})'
292
293    def referenced_fields(self):
294        return []
295
296    def __eq__(self, other):
297        return self.sign == other.sign and self.mask == other.mask
298
299    def __ne__(self, other):
300        return not self.__eq__(other)
301# end Field
302
303
304class MultiField:
305    """Class representing a compound instruction field"""
306    def __init__(self, subs, mask):
307        self.subs = subs
308        self.sign = subs[0].sign
309        self.mask = mask
310
311    def __str__(self):
312        return str(self.subs)
313
314    def str_extract(self, lvalue_formatter):
315        global bitop_width
316        ret = '0'
317        pos = 0
318        for f in reversed(self.subs):
319            ext = f.str_extract(lvalue_formatter)
320            if pos == 0:
321                ret = ext
322            else:
323                ret = f'deposit{bitop_width}({ret}, {pos}, {bitop_width - pos}, {ext})'
324            pos += f.len
325        return ret
326
327    def referenced_fields(self):
328        l = []
329        for f in self.subs:
330            l.extend(f.referenced_fields())
331        return l
332
333    def __ne__(self, other):
334        if len(self.subs) != len(other.subs):
335            return True
336        for a, b in zip(self.subs, other.subs):
337            if a.__class__ != b.__class__ or a != b:
338                return True
339        return False
340
341    def __eq__(self, other):
342        return not self.__ne__(other)
343# end MultiField
344
345
346class ConstField:
347    """Class representing an argument field with constant value"""
348    def __init__(self, value):
349        self.value = value
350        self.mask = 0
351        self.sign = value < 0
352
353    def __str__(self):
354        return str(self.value)
355
356    def str_extract(self, lvalue_formatter):
357        return str(self.value)
358
359    def referenced_fields(self):
360        return []
361
362    def __cmp__(self, other):
363        return self.value - other.value
364# end ConstField
365
366
367class FunctionField:
368    """Class representing a field passed through a function"""
369    def __init__(self, func, base):
370        self.mask = base.mask
371        self.sign = base.sign
372        self.base = base
373        self.func = func
374
375    def __str__(self):
376        return self.func + '(' + str(self.base) + ')'
377
378    def str_extract(self, lvalue_formatter):
379        return (self.func + '(ctx, '
380                + self.base.str_extract(lvalue_formatter) + ')')
381
382    def referenced_fields(self):
383        return self.base.referenced_fields()
384
385    def __eq__(self, other):
386        return self.func == other.func and self.base == other.base
387
388    def __ne__(self, other):
389        return not self.__eq__(other)
390# end FunctionField
391
392
393class ParameterField:
394    """Class representing a pseudo-field read from a function"""
395    def __init__(self, func):
396        self.mask = 0
397        self.sign = 0
398        self.func = func
399
400    def __str__(self):
401        return self.func
402
403    def str_extract(self, lvalue_formatter):
404        return self.func + '(ctx)'
405
406    def referenced_fields(self):
407        return []
408
409    def __eq__(self, other):
410        return self.func == other.func
411
412    def __ne__(self, other):
413        return not self.__eq__(other)
414# end ParameterField
415
416class NamedField:
417    """Class representing a field already named in the pattern"""
418    def __init__(self, name, sign, len):
419        self.mask = 0
420        self.sign = sign
421        self.len = len
422        self.name = name
423
424    def __str__(self):
425        return self.name
426
427    def str_extract(self, lvalue_formatter):
428        global bitop_width
429        s = 's' if self.sign else ''
430        lvalue = lvalue_formatter(self.name)
431        return f'{s}extract{bitop_width}({lvalue}, 0, {self.len})'
432
433    def referenced_fields(self):
434        return [self.name]
435
436    def __eq__(self, other):
437        return self.name == other.name
438
439    def __ne__(self, other):
440        return not self.__eq__(other)
441# end NamedField
442
443class Arguments:
444    """Class representing the extracted fields of a format"""
445    def __init__(self, nm, flds, types, extern):
446        self.name = nm
447        self.extern = extern
448        self.fields = flds
449        self.types = types
450
451    def __str__(self):
452        return self.name + ' ' + str(self.fields)
453
454    def struct_name(self):
455        return 'arg_' + self.name
456
457    def output_def(self):
458        if not self.extern:
459            output('typedef struct {\n')
460            for (n, t) in zip(self.fields, self.types):
461                output(f'    {t} {n};\n')
462            output('} ', self.struct_name(), ';\n\n')
463# end Arguments
464
465class General:
466    """Common code between instruction formats and instruction patterns"""
467    def __init__(self, name, lineno, base, fixb, fixm, udfm, fldm, flds, w):
468        self.name = name
469        self.file = input_file
470        self.lineno = lineno
471        self.base = base
472        self.fixedbits = fixb
473        self.fixedmask = fixm
474        self.undefmask = udfm
475        self.fieldmask = fldm
476        self.fields = flds
477        self.width = w
478        self.dangling = None
479
480    def __str__(self):
481        return self.name + ' ' + str_match_bits(self.fixedbits, self.fixedmask)
482
483    def str1(self, i):
484        return str_indent(i) + self.__str__()
485
486    def dangling_references(self):
487        # Return a list of all named references which aren't satisfied
488        # directly by this format/pattern. This will be either:
489        #  * a format referring to a field which is specified by the
490        #    pattern(s) using it
491        #  * a pattern referring to a field which is specified by the
492        #    format it uses
493        #  * a user error (referring to a field that doesn't exist at all)
494        if self.dangling is None:
495            # Compute this once and cache the answer
496            dangling = []
497            for n, f in self.fields.items():
498                for r in f.referenced_fields():
499                    if r not in self.fields:
500                        dangling.append(r)
501            self.dangling = dangling
502        return self.dangling
503
504    def output_fields(self, indent, lvalue_formatter):
505        # We use a topological sort to ensure that any use of NamedField
506        # comes after the initialization of the field it is referencing.
507        graph = {}
508        for n, f in self.fields.items():
509            refs = f.referenced_fields()
510            graph[n] = refs
511
512        try:
513            ts = TopologicalSorter(graph)
514            for n in ts.static_order():
515                # We only want to emit assignments for the keys
516                # in our fields list, not for anything that ends up
517                # in the tsort graph only because it was referenced as
518                # a NamedField.
519                try:
520                    f = self.fields[n]
521                    output(indent, lvalue_formatter(n), ' = ',
522                           f.str_extract(lvalue_formatter), ';\n')
523                except KeyError:
524                    pass
525        except CycleError as e:
526            # The second element of args is a list of nodes which form
527            # a cycle (there might be others too, but only one is reported).
528            # Pretty-print it to tell the user.
529            cycle = ' => '.join(e.args[1])
530            error(self.lineno, 'field definitions form a cycle: ' + cycle)
531# end General
532
533
534class Format(General):
535    """Class representing an instruction format"""
536
537    def extract_name(self):
538        global decode_function
539        return decode_function + '_extract_' + self.name
540
541    def output_extract(self):
542        output('static void ', self.extract_name(), '(DisasContext *ctx, ',
543               self.base.struct_name(), ' *a, ', insntype, ' insn)\n{\n')
544        self.output_fields(str_indent(4), lambda n: 'a->' + n)
545        output('}\n\n')
546# end Format
547
548
549class Pattern(General):
550    """Class representing an instruction pattern"""
551
552    def output_decl(self):
553        global translate_scope
554        global translate_prefix
555        output('typedef ', self.base.base.struct_name(),
556               ' arg_', self.name, ';\n')
557        output(translate_scope, 'bool ', translate_prefix, '_', self.name,
558               '(DisasContext *ctx, arg_', self.name, ' *a);\n')
559
560    def output_code(self, i, extracted, outerbits, outermask):
561        global translate_prefix
562        ind = str_indent(i)
563        arg = self.base.base.name
564        output(ind, '/* ', self.file, ':', str(self.lineno), ' */\n')
565        # We might have named references in the format that refer to fields
566        # in the pattern, or named references in the pattern that refer
567        # to fields in the format. This affects whether we extract the fields
568        # for the format before or after the ones for the pattern.
569        # For simplicity we don't allow cross references in both directions.
570        # This is also where we catch the syntax error of referring to
571        # a nonexistent field.
572        fmt_refs = self.base.dangling_references()
573        for r in fmt_refs:
574            if r not in self.fields:
575                error(self.lineno, f'format refers to undefined field {r}')
576        pat_refs = self.dangling_references()
577        for r in pat_refs:
578            if r not in self.base.fields:
579                error(self.lineno, f'pattern refers to undefined field {r}')
580        if pat_refs and fmt_refs:
581            error(self.lineno, ('pattern that uses fields defined in format '
582                                'cannot use format that uses fields defined '
583                                'in pattern'))
584        if fmt_refs:
585            # pattern fields first
586            self.output_fields(ind, lambda n: 'u.f_' + arg + '.' + n)
587            assert not extracted, "dangling fmt refs but it was already extracted"
588        if not extracted:
589            output(ind, self.base.extract_name(),
590                   '(ctx, &u.f_', arg, ', insn);\n')
591        if not fmt_refs:
592            # pattern fields last
593            self.output_fields(ind, lambda n: 'u.f_' + arg + '.' + n)
594
595        output(ind, 'if (', translate_prefix, '_', self.name,
596               '(ctx, &u.f_', arg, ')) return true;\n')
597
598    # Normal patterns do not have children.
599    def build_tree(self):
600        return
601    def prop_masks(self):
602        return
603    def prop_format(self):
604        return
605    def prop_width(self):
606        return
607
608# end Pattern
609
610
611class MultiPattern(General):
612    """Class representing a set of instruction patterns"""
613
614    def __init__(self, lineno):
615        self.file = input_file
616        self.lineno = lineno
617        self.pats = []
618        self.base = None
619        self.fixedbits = 0
620        self.fixedmask = 0
621        self.undefmask = 0
622        self.width = None
623
624    def __str__(self):
625        r = 'group'
626        if self.fixedbits is not None:
627            r += ' ' + str_match_bits(self.fixedbits, self.fixedmask)
628        return r
629
630    def output_decl(self):
631        for p in self.pats:
632            p.output_decl()
633
634    def prop_masks(self):
635        global insnmask
636
637        fixedmask = insnmask
638        undefmask = insnmask
639
640        # Collect fixedmask/undefmask for all of the children.
641        for p in self.pats:
642            p.prop_masks()
643            fixedmask &= p.fixedmask
644            undefmask &= p.undefmask
645
646        # Widen fixedmask until all fixedbits match
647        repeat = True
648        fixedbits = 0
649        while repeat and fixedmask != 0:
650            fixedbits = None
651            for p in self.pats:
652                thisbits = p.fixedbits & fixedmask
653                if fixedbits is None:
654                    fixedbits = thisbits
655                elif fixedbits != thisbits:
656                    fixedmask &= ~(fixedbits ^ thisbits)
657                    break
658            else:
659                repeat = False
660
661        self.fixedbits = fixedbits
662        self.fixedmask = fixedmask
663        self.undefmask = undefmask
664
665    def build_tree(self):
666        for p in self.pats:
667            p.build_tree()
668
669    def prop_format(self):
670        for p in self.pats:
671            p.prop_format()
672
673    def prop_width(self):
674        width = None
675        for p in self.pats:
676            p.prop_width()
677            if width is None:
678                width = p.width
679            elif width != p.width:
680                error_with_file(self.file, self.lineno,
681                                'width mismatch in patterns within braces')
682        self.width = width
683
684# end MultiPattern
685
686
687class IncMultiPattern(MultiPattern):
688    """Class representing an overlapping set of instruction patterns"""
689
690    def output_code(self, i, extracted, outerbits, outermask):
691        global translate_prefix
692        ind = str_indent(i)
693        for p in self.pats:
694            if outermask != p.fixedmask:
695                innermask = p.fixedmask & ~outermask
696                innerbits = p.fixedbits & ~outermask
697                output(ind, f'if ((insn & {whexC(innermask)}) == {whexC(innerbits)}) {{\n')
698                output(ind, f'    /* {str_match_bits(p.fixedbits, p.fixedmask)} */\n')
699                p.output_code(i + 4, extracted, p.fixedbits, p.fixedmask)
700                output(ind, '}\n')
701            else:
702                p.output_code(i, extracted, p.fixedbits, p.fixedmask)
703
704    def build_tree(self):
705        if not self.pats:
706            error_with_file(self.file, self.lineno, 'empty pattern group')
707        super().build_tree()
708
709#end IncMultiPattern
710
711
712class Tree:
713    """Class representing a node in a decode tree"""
714
715    def __init__(self, fm, tm):
716        self.fixedmask = fm
717        self.thismask = tm
718        self.subs = []
719        self.base = None
720
721    def str1(self, i):
722        ind = str_indent(i)
723        r = ind + whex(self.fixedmask)
724        if self.format:
725            r += ' ' + self.format.name
726        r += ' [\n'
727        for (b, s) in self.subs:
728            r += ind + f'  {whex(b)}:\n'
729            r += s.str1(i + 4) + '\n'
730        r += ind + ']'
731        return r
732
733    def __str__(self):
734        return self.str1(0)
735
736    def output_code(self, i, extracted, outerbits, outermask):
737        ind = str_indent(i)
738
739        # If we identified all nodes below have the same format,
740        # extract the fields now. But don't do it if the format relies
741        # on named fields from the insn pattern, as those won't have
742        # been initialised at this point.
743        if not extracted and self.base and not self.base.dangling_references():
744            output(ind, self.base.extract_name(),
745                   '(ctx, &u.f_', self.base.base.name, ', insn);\n')
746            extracted = True
747
748        # Attempt to aid the compiler in producing compact switch statements.
749        # If the bits in the mask are contiguous, extract them.
750        sh = is_contiguous(self.thismask)
751        if sh > 0:
752            # Propagate SH down into the local functions.
753            def str_switch(b, sh=sh):
754                return f'(insn >> {sh}) & {b >> sh:#x}'
755
756            def str_case(b, sh=sh):
757                return hex(b >> sh)
758        else:
759            def str_switch(b):
760                return f'insn & {whexC(b)}'
761
762            def str_case(b):
763                return whexC(b)
764
765        output(ind, 'switch (', str_switch(self.thismask), ') {\n')
766        for b, s in sorted(self.subs):
767            assert (self.thismask & ~s.fixedmask) == 0
768            innermask = outermask | self.thismask
769            innerbits = outerbits | b
770            output(ind, 'case ', str_case(b), ':\n')
771            output(ind, '    /* ',
772                   str_match_bits(innerbits, innermask), ' */\n')
773            s.output_code(i + 4, extracted, innerbits, innermask)
774            output(ind, '    break;\n')
775        output(ind, '}\n')
776# end Tree
777
778
779class ExcMultiPattern(MultiPattern):
780    """Class representing a non-overlapping set of instruction patterns"""
781
782    def output_code(self, i, extracted, outerbits, outermask):
783        # Defer everything to our decomposed Tree node
784        self.tree.output_code(i, extracted, outerbits, outermask)
785
786    @staticmethod
787    def __build_tree(pats, outerbits, outermask):
788        # Find the intersection of all remaining fixedmask.
789        innermask = ~outermask & insnmask
790        for i in pats:
791            innermask &= i.fixedmask
792
793        if innermask == 0:
794            # Edge condition: One pattern covers the entire insnmask
795            if len(pats) == 1:
796                t = Tree(outermask, innermask)
797                t.subs.append((0, pats[0]))
798                return t
799
800            text = 'overlapping patterns:'
801            for p in pats:
802                text += '\n' + p.file + ':' + str(p.lineno) + ': ' + str(p)
803            error_with_file(pats[0].file, pats[0].lineno, text)
804
805        fullmask = outermask | innermask
806
807        # Sort each element of pats into the bin selected by the mask.
808        bins = {}
809        for i in pats:
810            fb = i.fixedbits & innermask
811            if fb in bins:
812                bins[fb].append(i)
813            else:
814                bins[fb] = [i]
815
816        # We must recurse if any bin has more than one element or if
817        # the single element in the bin has not been fully matched.
818        t = Tree(fullmask, innermask)
819
820        for b, l in bins.items():
821            s = l[0]
822            if len(l) > 1 or s.fixedmask & ~fullmask != 0:
823                s = ExcMultiPattern.__build_tree(l, b | outerbits, fullmask)
824            t.subs.append((b, s))
825
826        return t
827
828    def build_tree(self):
829        super().build_tree()
830        self.tree = self.__build_tree(self.pats, self.fixedbits,
831                                      self.fixedmask)
832
833    @staticmethod
834    def __prop_format(tree):
835        """Propagate Format objects into the decode tree"""
836
837        # Depth first search.
838        for (b, s) in tree.subs:
839            if isinstance(s, Tree):
840                ExcMultiPattern.__prop_format(s)
841
842        # If all entries in SUBS have the same format, then
843        # propagate that into the tree.
844        f = None
845        for (b, s) in tree.subs:
846            if f is None:
847                f = s.base
848                if f is None:
849                    return
850            if f is not s.base:
851                return
852        tree.base = f
853
854    def prop_format(self):
855        super().prop_format()
856        self.__prop_format(self.tree)
857
858# end ExcMultiPattern
859
860
861def parse_field(lineno, name, toks):
862    """Parse one instruction field from TOKS at LINENO"""
863    global fields
864    global insnwidth
865    global re_C_ident
866
867    # A "simple" field will have only one entry;
868    # a "multifield" will have several.
869    subs = []
870    width = 0
871    func = None
872    for t in toks:
873        if re.match('^!function=', t):
874            if func:
875                error(lineno, 'duplicate function')
876            func = t.split('=')
877            func = func[1]
878            continue
879
880        if re.fullmatch(re_C_ident + ':s[0-9]+', t):
881            # Signed named field
882            subtoks = t.split(':')
883            n = subtoks[0]
884            le = int(subtoks[1])
885            f = NamedField(n, True, le)
886            subs.append(f)
887            width += le
888            continue
889        if re.fullmatch(re_C_ident + ':[0-9]+', t):
890            # Unsigned named field
891            subtoks = t.split(':')
892            n = subtoks[0]
893            le = int(subtoks[1])
894            f = NamedField(n, False, le)
895            subs.append(f)
896            width += le
897            continue
898
899        if re.fullmatch('[0-9]+:s[0-9]+', t):
900            # Signed field extract
901            subtoks = t.split(':s')
902            sign = True
903        elif re.fullmatch('[0-9]+:[0-9]+', t):
904            # Unsigned field extract
905            subtoks = t.split(':')
906            sign = False
907        else:
908            error(lineno, f'invalid field token "{t}"')
909        po = int(subtoks[0])
910        le = int(subtoks[1])
911        if po + le > insnwidth:
912            error(lineno, f'field {t} too large')
913        f = Field(sign, po, le)
914        subs.append(f)
915        width += le
916
917    if width > insnwidth:
918        error(lineno, 'field too large')
919    if len(subs) == 0:
920        if func:
921            f = ParameterField(func)
922        else:
923            error(lineno, 'field with no value')
924    else:
925        if len(subs) == 1:
926            f = subs[0]
927        else:
928            mask = 0
929            for s in subs:
930                if mask & s.mask:
931                    error(lineno, 'field components overlap')
932                mask |= s.mask
933            f = MultiField(subs, mask)
934        if func:
935            f = FunctionField(func, f)
936
937    if name in fields:
938        error(lineno, 'duplicate field', name)
939    fields[name] = f
940# end parse_field
941
942
943def parse_arguments(lineno, name, toks):
944    """Parse one argument set from TOKS at LINENO"""
945    global arguments
946    global re_C_ident
947    global anyextern
948
949    flds = []
950    types = []
951    extern = False
952    for n in toks:
953        if re.fullmatch('!extern', n):
954            extern = True
955            anyextern = True
956            continue
957        if re.fullmatch(re_C_ident + ':' + re_C_ident, n):
958            (n, t) = n.split(':')
959        elif re.fullmatch(re_C_ident, n):
960            t = 'int'
961        else:
962            error(lineno, f'invalid argument set token "{n}"')
963        if n in flds:
964            error(lineno, f'duplicate argument "{n}"')
965        flds.append(n)
966        types.append(t)
967
968    if name in arguments:
969        error(lineno, 'duplicate argument set', name)
970    arguments[name] = Arguments(name, flds, types, extern)
971# end parse_arguments
972
973
974def lookup_field(lineno, name):
975    global fields
976    if name in fields:
977        return fields[name]
978    error(lineno, 'undefined field', name)
979
980
981def add_field(lineno, flds, new_name, f):
982    if new_name in flds:
983        error(lineno, 'duplicate field', new_name)
984    flds[new_name] = f
985    return flds
986
987
988def add_field_byname(lineno, flds, new_name, old_name):
989    return add_field(lineno, flds, new_name, lookup_field(lineno, old_name))
990
991
992def infer_argument_set(flds):
993    global arguments
994    global decode_function
995
996    for arg in arguments.values():
997        if eq_fields_for_args(flds, arg):
998            return arg
999
1000    name = decode_function + str(len(arguments))
1001    arg = Arguments(name, flds.keys(), ['int'] * len(flds), False)
1002    arguments[name] = arg
1003    return arg
1004
1005
1006def infer_format(arg, fieldmask, flds, width):
1007    global arguments
1008    global formats
1009    global decode_function
1010
1011    const_flds = {}
1012    var_flds = {}
1013    for n, c in flds.items():
1014        if c is ConstField:
1015            const_flds[n] = c
1016        else:
1017            var_flds[n] = c
1018
1019    if not arg:
1020        arg = infer_argument_set(flds)
1021
1022    # Look for an existing format with the same argument set and fields
1023    for fmt in formats.values():
1024        if fmt.base != arg:
1025            continue
1026        if fieldmask != fmt.fieldmask:
1027            continue
1028        if width != fmt.width:
1029            continue
1030        if not eq_fields_for_fmts(flds, fmt.fields):
1031            continue
1032        return (fmt, const_flds)
1033
1034    name = decode_function + '_Fmt_' + str(len(formats))
1035
1036    fmt = Format(name, 0, arg, 0, 0, 0, fieldmask, var_flds, width)
1037    formats[name] = fmt
1038
1039    return (fmt, const_flds)
1040# end infer_format
1041
1042
1043def parse_generic(lineno, parent_pat, name, toks):
1044    """Parse one instruction format from TOKS at LINENO"""
1045    global fields
1046    global arguments
1047    global formats
1048    global allpatterns
1049    global re_arg_ident
1050    global re_fld_ident
1051    global re_fmt_ident
1052    global re_C_ident
1053    global insnwidth
1054    global insnmask
1055    global variablewidth
1056
1057    is_format = parent_pat is None
1058
1059    fixedmask = 0
1060    fixedbits = 0
1061    undefmask = 0
1062    width = 0
1063    flds = {}
1064    arg = None
1065    fmt = None
1066    for t in toks:
1067        # '&Foo' gives a format an explicit argument set.
1068        if re.fullmatch(re_arg_ident, t):
1069            tt = t[1:]
1070            if arg:
1071                error(lineno, 'multiple argument sets')
1072            if tt in arguments:
1073                arg = arguments[tt]
1074            else:
1075                error(lineno, 'undefined argument set', t)
1076            continue
1077
1078        # '@Foo' gives a pattern an explicit format.
1079        if re.fullmatch(re_fmt_ident, t):
1080            tt = t[1:]
1081            if fmt:
1082                error(lineno, 'multiple formats')
1083            if tt in formats:
1084                fmt = formats[tt]
1085            else:
1086                error(lineno, 'undefined format', t)
1087            continue
1088
1089        # '%Foo' imports a field.
1090        if re.fullmatch(re_fld_ident, t):
1091            tt = t[1:]
1092            flds = add_field_byname(lineno, flds, tt, tt)
1093            continue
1094
1095        # 'Foo=%Bar' imports a field with a different name.
1096        if re.fullmatch(re_C_ident + '=' + re_fld_ident, t):
1097            (fname, iname) = t.split('=%')
1098            flds = add_field_byname(lineno, flds, fname, iname)
1099            continue
1100
1101        # 'Foo=number' sets an argument field to a constant value
1102        if re.fullmatch(re_C_ident + '=[+-]?[0-9]+', t):
1103            (fname, value) = t.split('=')
1104            value = int(value)
1105            flds = add_field(lineno, flds, fname, ConstField(value))
1106            continue
1107
1108        # Pattern of 0s, 1s, dots and dashes indicate required zeros,
1109        # required ones, or dont-cares.
1110        if re.fullmatch('[01.-]+', t):
1111            shift = len(t)
1112            fms = t.replace('0', '1')
1113            fms = fms.replace('.', '0')
1114            fms = fms.replace('-', '0')
1115            fbs = t.replace('.', '0')
1116            fbs = fbs.replace('-', '0')
1117            ubm = t.replace('1', '0')
1118            ubm = ubm.replace('.', '0')
1119            ubm = ubm.replace('-', '1')
1120            fms = int(fms, 2)
1121            fbs = int(fbs, 2)
1122            ubm = int(ubm, 2)
1123            fixedbits = (fixedbits << shift) | fbs
1124            fixedmask = (fixedmask << shift) | fms
1125            undefmask = (undefmask << shift) | ubm
1126        # Otherwise, fieldname:fieldwidth
1127        elif re.fullmatch(re_C_ident + ':s?[0-9]+', t):
1128            (fname, flen) = t.split(':')
1129            sign = False
1130            if flen[0] == 's':
1131                sign = True
1132                flen = flen[1:]
1133            shift = int(flen, 10)
1134            if shift + width > insnwidth:
1135                error(lineno, f'field {fname} exceeds insnwidth')
1136            f = Field(sign, insnwidth - width - shift, shift)
1137            flds = add_field(lineno, flds, fname, f)
1138            fixedbits <<= shift
1139            fixedmask <<= shift
1140            undefmask <<= shift
1141        else:
1142            error(lineno, f'invalid token "{t}"')
1143        width += shift
1144
1145    if variablewidth and width < insnwidth and width % 8 == 0:
1146        shift = insnwidth - width
1147        fixedbits <<= shift
1148        fixedmask <<= shift
1149        undefmask <<= shift
1150        undefmask |= (1 << shift) - 1
1151
1152    # We should have filled in all of the bits of the instruction.
1153    elif not (is_format and width == 0) and width != insnwidth:
1154        error(lineno, f'definition has {width} bits')
1155
1156    # Do not check for fields overlapping fields; one valid usage
1157    # is to be able to duplicate fields via import.
1158    fieldmask = 0
1159    for f in flds.values():
1160        fieldmask |= f.mask
1161
1162    # Fix up what we've parsed to match either a format or a pattern.
1163    if is_format:
1164        # Formats cannot reference formats.
1165        if fmt:
1166            error(lineno, 'format referencing format')
1167        # If an argument set is given, then there should be no fields
1168        # without a place to store it.
1169        if arg:
1170            for f in flds.keys():
1171                if f not in arg.fields:
1172                    error(lineno, f'field {f} not in argument set {arg.name}')
1173        else:
1174            arg = infer_argument_set(flds)
1175        if name in formats:
1176            error(lineno, 'duplicate format name', name)
1177        fmt = Format(name, lineno, arg, fixedbits, fixedmask,
1178                     undefmask, fieldmask, flds, width)
1179        formats[name] = fmt
1180    else:
1181        # Patterns can reference a format ...
1182        if fmt:
1183            # ... but not an argument simultaneously
1184            if arg:
1185                error(lineno, 'pattern specifies both format and argument set')
1186            if fixedmask & fmt.fixedmask:
1187                error(lineno, 'pattern fixed bits overlap format fixed bits')
1188            if width != fmt.width:
1189                error(lineno, 'pattern uses format of different width')
1190            fieldmask |= fmt.fieldmask
1191            fixedbits |= fmt.fixedbits
1192            fixedmask |= fmt.fixedmask
1193            undefmask |= fmt.undefmask
1194        else:
1195            (fmt, flds) = infer_format(arg, fieldmask, flds, width)
1196        arg = fmt.base
1197        for f in flds.keys():
1198            if f not in arg.fields:
1199                error(lineno, f'field {f} not in argument set {arg.name}')
1200            if f in fmt.fields.keys():
1201                error(lineno, f'field {f} set by format and pattern')
1202        for f in arg.fields:
1203            if f not in flds.keys() and f not in fmt.fields.keys():
1204                error(lineno, f'field {f} not initialized')
1205        pat = Pattern(name, lineno, fmt, fixedbits, fixedmask,
1206                      undefmask, fieldmask, flds, width)
1207        parent_pat.pats.append(pat)
1208        allpatterns.append(pat)
1209
1210    # Validate the masks that we have assembled.
1211    if fieldmask & fixedmask:
1212        error(lineno, 'fieldmask overlaps fixedmask ',
1213              f'({whex(fieldmask)} & {whex(fixedmask)})')
1214    if fieldmask & undefmask:
1215        error(lineno, 'fieldmask overlaps undefmask ',
1216              f'({whex(fieldmask)} & {whex(undefmask)})')
1217    if fixedmask & undefmask:
1218        error(lineno, 'fixedmask overlaps undefmask ',
1219              f'({whex(fixedmask)} & {whex(undefmask)})')
1220    if not is_format:
1221        allbits = fieldmask | fixedmask | undefmask
1222        if allbits != insnmask:
1223            error(lineno, 'bits left unspecified ',
1224                  f'({whex(allbits ^ insnmask)})')
1225# end parse_general
1226
1227
1228def parse_file(f, parent_pat):
1229    """Parse all of the patterns within a file"""
1230    global re_arg_ident
1231    global re_fld_ident
1232    global re_fmt_ident
1233    global re_pat_ident
1234
1235    # Read all of the lines of the file.  Concatenate lines
1236    # ending in backslash; discard empty lines and comments.
1237    toks = []
1238    lineno = 0
1239    nesting = 0
1240    nesting_pats = []
1241
1242    for line in f:
1243        lineno += 1
1244
1245        # Expand and strip spaces, to find indent.
1246        line = line.rstrip()
1247        line = line.expandtabs()
1248        len1 = len(line)
1249        line = line.lstrip()
1250        len2 = len(line)
1251
1252        # Discard comments
1253        end = line.find('#')
1254        if end >= 0:
1255            line = line[:end]
1256
1257        t = line.split()
1258        if len(toks) != 0:
1259            # Next line after continuation
1260            toks.extend(t)
1261        else:
1262            # Allow completely blank lines.
1263            if len1 == 0:
1264                continue
1265            indent = len1 - len2
1266            # Empty line due to comment.
1267            if len(t) == 0:
1268                # Indentation must be correct, even for comment lines.
1269                if indent != nesting:
1270                    error(lineno, 'indentation ', indent, ' != ', nesting)
1271                continue
1272            start_lineno = lineno
1273            toks = t
1274
1275        # Continuation?
1276        if toks[-1] == '\\':
1277            toks.pop()
1278            continue
1279
1280        name = toks[0]
1281        del toks[0]
1282
1283        # End nesting?
1284        if name == '}' or name == ']':
1285            if len(toks) != 0:
1286                error(start_lineno, 'extra tokens after close brace')
1287
1288            # Make sure { } and [ ] nest properly.
1289            if (name == '}') != isinstance(parent_pat, IncMultiPattern):
1290                error(lineno, 'mismatched close brace')
1291
1292            try:
1293                parent_pat = nesting_pats.pop()
1294            except:
1295                error(lineno, 'extra close brace')
1296
1297            nesting -= 2
1298            if indent != nesting:
1299                error(lineno, 'indentation ', indent, ' != ', nesting)
1300
1301            toks = []
1302            continue
1303
1304        # Everything else should have current indentation.
1305        if indent != nesting:
1306            error(start_lineno, 'indentation ', indent, ' != ', nesting)
1307
1308        # Start nesting?
1309        if name == '{' or name == '[':
1310            if len(toks) != 0:
1311                error(start_lineno, 'extra tokens after open brace')
1312
1313            if name == '{':
1314                nested_pat = IncMultiPattern(start_lineno)
1315            else:
1316                nested_pat = ExcMultiPattern(start_lineno)
1317            parent_pat.pats.append(nested_pat)
1318            nesting_pats.append(parent_pat)
1319            parent_pat = nested_pat
1320
1321            nesting += 2
1322            toks = []
1323            continue
1324
1325        # Determine the type of object needing to be parsed.
1326        if re.fullmatch(re_fld_ident, name):
1327            parse_field(start_lineno, name[1:], toks)
1328        elif re.fullmatch(re_arg_ident, name):
1329            parse_arguments(start_lineno, name[1:], toks)
1330        elif re.fullmatch(re_fmt_ident, name):
1331            parse_generic(start_lineno, None, name[1:], toks)
1332        elif re.fullmatch(re_pat_ident, name):
1333            parse_generic(start_lineno, parent_pat, name, toks)
1334        else:
1335            error(lineno, f'invalid token "{name}"')
1336        toks = []
1337
1338    if nesting != 0:
1339        error(lineno, 'missing close brace')
1340# end parse_file
1341
1342
1343class SizeTree:
1344    """Class representing a node in a size decode tree"""
1345
1346    def __init__(self, m, w):
1347        self.mask = m
1348        self.subs = []
1349        self.base = None
1350        self.width = w
1351
1352    def str1(self, i):
1353        ind = str_indent(i)
1354        r = ind + whex(self.mask) + ' [\n'
1355        for (b, s) in self.subs:
1356            r += ind + f'  {whex(b)}:\n'
1357            r += s.str1(i + 4) + '\n'
1358        r += ind + ']'
1359        return r
1360
1361    def __str__(self):
1362        return self.str1(0)
1363
1364    def output_code(self, i, extracted, outerbits, outermask):
1365        ind = str_indent(i)
1366
1367        # If we need to load more bytes to test, do so now.
1368        if extracted < self.width:
1369            output(ind, f'insn = {decode_function}_load_bytes',
1370                   f'(ctx, insn, {extracted // 8}, {self.width // 8});\n')
1371            extracted = self.width
1372
1373        # Attempt to aid the compiler in producing compact switch statements.
1374        # If the bits in the mask are contiguous, extract them.
1375        sh = is_contiguous(self.mask)
1376        if sh > 0:
1377            # Propagate SH down into the local functions.
1378            def str_switch(b, sh=sh):
1379                return f'(insn >> {sh}) & {b >> sh:#x}'
1380
1381            def str_case(b, sh=sh):
1382                return hex(b >> sh)
1383        else:
1384            def str_switch(b):
1385                return f'insn & {whexC(b)}'
1386
1387            def str_case(b):
1388                return whexC(b)
1389
1390        output(ind, 'switch (', str_switch(self.mask), ') {\n')
1391        for b, s in sorted(self.subs):
1392            innermask = outermask | self.mask
1393            innerbits = outerbits | b
1394            output(ind, 'case ', str_case(b), ':\n')
1395            output(ind, '    /* ',
1396                   str_match_bits(innerbits, innermask), ' */\n')
1397            s.output_code(i + 4, extracted, innerbits, innermask)
1398        output(ind, '}\n')
1399        output(ind, 'return insn;\n')
1400# end SizeTree
1401
1402class SizeLeaf:
1403    """Class representing a leaf node in a size decode tree"""
1404
1405    def __init__(self, m, w):
1406        self.mask = m
1407        self.width = w
1408
1409    def str1(self, i):
1410        return str_indent(i) + whex(self.mask)
1411
1412    def __str__(self):
1413        return self.str1(0)
1414
1415    def output_code(self, i, extracted, outerbits, outermask):
1416        global decode_function
1417        ind = str_indent(i)
1418
1419        # If we need to load more bytes, do so now.
1420        if extracted < self.width:
1421            output(ind, f'insn = {decode_function}_load_bytes',
1422                   f'(ctx, insn, {extracted // 8}, {self.width // 8});\n')
1423            extracted = self.width
1424        output(ind, 'return insn;\n')
1425# end SizeLeaf
1426
1427
1428def build_size_tree(pats, width, outerbits, outermask):
1429    global insnwidth
1430
1431    # Collect the mask of bits that are fixed in this width
1432    innermask = 0xff << (insnwidth - width)
1433    innermask &= ~outermask
1434    minwidth = None
1435    onewidth = True
1436    for i in pats:
1437        innermask &= i.fixedmask
1438        if minwidth is None:
1439            minwidth = i.width
1440        elif minwidth != i.width:
1441            onewidth = False;
1442            if minwidth < i.width:
1443                minwidth = i.width
1444
1445    if onewidth:
1446        return SizeLeaf(innermask, minwidth)
1447
1448    if innermask == 0:
1449        if width < minwidth:
1450            return build_size_tree(pats, width + 8, outerbits, outermask)
1451
1452        pnames = []
1453        for p in pats:
1454            pnames.append(p.name + ':' + p.file + ':' + str(p.lineno))
1455        error_with_file(pats[0].file, pats[0].lineno,
1456                        f'overlapping patterns size {width}:', pnames)
1457
1458    bins = {}
1459    for i in pats:
1460        fb = i.fixedbits & innermask
1461        if fb in bins:
1462            bins[fb].append(i)
1463        else:
1464            bins[fb] = [i]
1465
1466    fullmask = outermask | innermask
1467    lens = sorted(bins.keys())
1468    if len(lens) == 1:
1469        b = lens[0]
1470        return build_size_tree(bins[b], width + 8, b | outerbits, fullmask)
1471
1472    r = SizeTree(innermask, width)
1473    for b, l in bins.items():
1474        s = build_size_tree(l, width, b | outerbits, fullmask)
1475        r.subs.append((b, s))
1476    return r
1477# end build_size_tree
1478
1479
1480def prop_size(tree):
1481    """Propagate minimum widths up the decode size tree"""
1482
1483    if isinstance(tree, SizeTree):
1484        min = None
1485        for (b, s) in tree.subs:
1486            width = prop_size(s)
1487            if min is None or min > width:
1488                min = width
1489        assert min >= tree.width
1490        tree.width = min
1491    else:
1492        min = tree.width
1493    return min
1494# end prop_size
1495
1496
1497def main():
1498    global arguments
1499    global formats
1500    global allpatterns
1501    global translate_scope
1502    global translate_prefix
1503    global output_fd
1504    global output_file
1505    global output_null
1506    global input_file
1507    global insnwidth
1508    global insntype
1509    global insnmask
1510    global decode_function
1511    global bitop_width
1512    global variablewidth
1513    global anyextern
1514    global testforerror
1515
1516    decode_scope = 'static '
1517
1518    long_opts = ['decode=', 'translate=', 'output=', 'insnwidth=',
1519                 'static-decode=', 'varinsnwidth=', 'test-for-error',
1520                 'output-null']
1521    try:
1522        (opts, args) = getopt.gnu_getopt(sys.argv[1:], 'o:vw:', long_opts)
1523    except getopt.GetoptError as err:
1524        error(0, err)
1525    for o, a in opts:
1526        if o in ('-o', '--output'):
1527            output_file = a
1528        elif o == '--decode':
1529            decode_function = a
1530            decode_scope = ''
1531        elif o == '--static-decode':
1532            decode_function = a
1533        elif o == '--translate':
1534            translate_prefix = a
1535            translate_scope = ''
1536        elif o in ('-w', '--insnwidth', '--varinsnwidth'):
1537            if o == '--varinsnwidth':
1538                variablewidth = True
1539            insnwidth = int(a)
1540            if insnwidth == 16:
1541                insntype = 'uint16_t'
1542                insnmask = 0xffff
1543            elif insnwidth == 64:
1544                insntype = 'uint64_t'
1545                insnmask = 0xffffffffffffffff
1546                bitop_width = 64
1547            elif insnwidth != 32:
1548                error(0, 'cannot handle insns of width', insnwidth)
1549        elif o == '--test-for-error':
1550            testforerror = True
1551        elif o == '--output-null':
1552            output_null = True
1553        else:
1554            assert False, 'unhandled option'
1555
1556    if len(args) < 1:
1557        error(0, 'missing input file')
1558
1559    toppat = ExcMultiPattern(0)
1560
1561    for filename in args:
1562        input_file = filename
1563        f = open(filename, 'rt', encoding='utf-8')
1564        parse_file(f, toppat)
1565        f.close()
1566
1567    # We do not want to compute masks for toppat, because those masks
1568    # are used as a starting point for build_tree.  For toppat, we must
1569    # insist that decode begins from naught.
1570    for i in toppat.pats:
1571        i.prop_masks()
1572
1573    toppat.build_tree()
1574    toppat.prop_format()
1575
1576    if variablewidth:
1577        for i in toppat.pats:
1578            i.prop_width()
1579        stree = build_size_tree(toppat.pats, 8, 0, 0)
1580        prop_size(stree)
1581
1582    if output_null:
1583        output_fd = open(os.devnull, 'wt', encoding='utf-8', errors="ignore")
1584    elif output_file:
1585        output_fd = open(output_file, 'wt', encoding='utf-8')
1586    else:
1587        output_fd = io.TextIOWrapper(sys.stdout.buffer,
1588                                     encoding=sys.stdout.encoding,
1589                                     errors="ignore")
1590
1591    output_autogen()
1592    for n in sorted(arguments.keys()):
1593        f = arguments[n]
1594        f.output_def()
1595
1596    # A single translate function can be invoked for different patterns.
1597    # Make sure that the argument sets are the same, and declare the
1598    # function only once.
1599    #
1600    # If we're sharing formats, we're likely also sharing trans_* functions,
1601    # but we can't tell which ones.  Prevent issues from the compiler by
1602    # suppressing redundant declaration warnings.
1603    if anyextern:
1604        output("#pragma GCC diagnostic push\n",
1605               "#pragma GCC diagnostic ignored \"-Wredundant-decls\"\n",
1606               "#ifdef __clang__\n"
1607               "#  pragma GCC diagnostic ignored \"-Wtypedef-redefinition\"\n",
1608               "#endif\n\n")
1609
1610    out_pats = {}
1611    for i in allpatterns:
1612        if i.name in out_pats:
1613            p = out_pats[i.name]
1614            if i.base.base != p.base.base:
1615                error(0, i.name, ' has conflicting argument sets')
1616        else:
1617            i.output_decl()
1618            out_pats[i.name] = i
1619    output('\n')
1620
1621    if anyextern:
1622        output("#pragma GCC diagnostic pop\n\n")
1623
1624    for n in sorted(formats.keys()):
1625        f = formats[n]
1626        f.output_extract()
1627
1628    output(decode_scope, 'bool ', decode_function,
1629           '(DisasContext *ctx, ', insntype, ' insn)\n{\n')
1630
1631    i4 = str_indent(4)
1632
1633    if len(allpatterns) != 0:
1634        output(i4, 'union {\n')
1635        for n in sorted(arguments.keys()):
1636            f = arguments[n]
1637            output(i4, i4, f.struct_name(), ' f_', f.name, ';\n')
1638        output(i4, '} u;\n\n')
1639        toppat.output_code(4, False, 0, 0)
1640
1641    output(i4, 'return false;\n')
1642    output('}\n')
1643
1644    if variablewidth:
1645        output('\n', decode_scope, insntype, ' ', decode_function,
1646               '_load(DisasContext *ctx)\n{\n',
1647               '    ', insntype, ' insn = 0;\n\n')
1648        stree.output_code(4, 0, 0, 0)
1649        output('}\n')
1650
1651    if output_file:
1652        output_fd.close()
1653    exit(1 if testforerror else 0)
1654# end main
1655
1656
1657if __name__ == '__main__':
1658    main()
1659