qemu/scripts/decodetree.py

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#!/usr/bin/env python3
# Copyright (c) 2018 Linaro Limited
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, see <http://www.gnu.org/licenses/>.
#
#
# Generate a decoding tree from a specification file.
# See the syntax and semantics in docs/devel/decodetree.rst.
#
import io
import os
import re
import sys
import getopt
insnwidth = 32
bitop_width = 32
insnmask = 0xffffffff
variablewidth = False
fields = {}
arguments = {}
formats = {}
allpatterns = []
anyextern = False
translate_prefix = 'trans'
translate_scope = 'static '
input_file = ''
output_file = None
output_fd = None
insntype = 'uint32_t'
decode_function = 'decode'
# An identifier for C.
re_C_ident = '[a-zA-Z][a-zA-Z0-9_]*'
# Identifiers for Arguments, Fields, Formats and Patterns.
re_arg_ident = '&[a-zA-Z0-9_]*'
re_fld_ident = '%[a-zA-Z0-9_]*'
re_fmt_ident = '@[a-zA-Z0-9_]*'
re_pat_ident = '[a-zA-Z0-9_]*'
def error_with_file(file, lineno, *args):
"""Print an error message from file:line and args and exit."""
global output_file
global output_fd
prefix = ''
if file:
prefix += f'{file}:'
if lineno:
prefix += f'{lineno}:'
if prefix:
prefix += ' '
print(prefix, end='error: ', file=sys.stderr)
print(*args, file=sys.stderr)
if output_file and output_fd:
output_fd.close()
os.remove(output_file)
exit(1)
# end error_with_file
def error(lineno, *args):
error_with_file(input_file, lineno, *args)
# end error
def output(*args):
global output_fd
for a in args:
output_fd.write(a)
def output_autogen():
output('/* This file is autogenerated by scripts/decodetree.py. */\n\n')
def str_indent(c):
"""Return a string with C spaces"""
return ' ' * c
def str_fields(fields):
"""Return a string uniquely identifying FIELDS"""
r = ''
for n in sorted(fields.keys()):
r += '_' + n
return r[1:]
def whex(val):
"""Return a hex string for val padded for insnwidth"""
global insnwidth
return f'0x{val:0{insnwidth // 4}x}'
def whexC(val):
"""Return a hex string for val padded for insnwidth,
and with the proper suffix for a C constant."""
suffix = ''
if val >= 0x100000000:
suffix = 'ull'
elif val >= 0x80000000:
suffix = 'u'
return whex(val) + suffix
def str_match_bits(bits, mask):
"""Return a string pretty-printing BITS/MASK"""
global insnwidth
i = 1 << (insnwidth - 1)
space = 0x01010100
r = ''
while i != 0:
if i & mask:
if i & bits:
r += '1'
else:
r += '0'
else:
r += '.'
if i & space:
r += ' '
i >>= 1
return r
def is_pow2(x):
"""Return true iff X is equal to a power of 2."""
return (x & (x - 1)) == 0
def ctz(x):
"""Return the number of times 2 factors into X."""
assert x != 0
r = 0
while ((x >> r) & 1) == 0:
r += 1
return r
def is_contiguous(bits):
if bits == 0:
return -1
shift = ctz(bits)
if is_pow2((bits >> shift) + 1):
return shift
else:
return -1
def eq_fields_for_args(flds_a, arg):
if len(flds_a) != len(arg.fields):
return False
# Only allow inference on default types
for t in arg.types:
if t != 'int':
return False
for k, a in flds_a.items():
if k not in arg.fields:
return False
return True
def eq_fields_for_fmts(flds_a, flds_b):
if len(flds_a) != len(flds_b):
return False
for k, a in flds_a.items():
if k not in flds_b:
return False
b = flds_b[k]
if a.__class__ != b.__class__ or a != b:
return False
return True
class Field:
"""Class representing a simple instruction field"""
def __init__(self, sign, pos, len):
self.sign = sign
self.pos = pos
self.len = len
self.mask = ((1 << len) - 1) << pos
def __str__(self):
if self.sign:
s = 's'
else:
s = ''
return str(self.pos) + ':' + s + str(self.len)
def str_extract(self):
global bitop_width
s = 's' if self.sign else ''
return f'{s}extract{bitop_width}(insn, {self.pos}, {self.len})'
def __eq__(self, other):
return self.sign == other.sign and self.mask == other.mask
def __ne__(self, other):
return not self.__eq__(other)
# end Field
class MultiField:
"""Class representing a compound instruction field"""
def __init__(self, subs, mask):
self.subs = subs
self.sign = subs[0].sign
self.mask = mask
def __str__(self):
return str(self.subs)
def str_extract(self):
global bitop_width
ret = '0'
pos = 0
for f in reversed(self.subs):
ext = f.str_extract()
if pos == 0:
ret = ext
else:
ret = f'deposit{bitop_width}({ret}, {pos}, {bitop_width - pos}, {ext})'
pos += f.len
return ret
def __ne__(self, other):
if len(self.subs) != len(other.subs):
return True
for a, b in zip(self.subs, other.subs):
if a.__class__ != b.__class__ or a != b:
return True
return False
def __eq__(self, other):
return not self.__ne__(other)
# end MultiField
class ConstField:
"""Class representing an argument field with constant value"""
def __init__(self, value):
self.value = value
self.mask = 0
self.sign = value < 0
def __str__(self):
return str(self.value)
def str_extract(self):
return str(self.value)
def __cmp__(self, other):
return self.value - other.value
# end ConstField
class FunctionField:
"""Class representing a field passed through a function"""
def __init__(self, func, base):
self.mask = base.mask
self.sign = base.sign
self.base = base
self.func = func
def __str__(self):
return self.func + '(' + str(self.base) + ')'
def str_extract(self):
return self.func + '(ctx, ' + self.base.str_extract() + ')'
def __eq__(self, other):
return self.func == other.func and self.base == other.base
def __ne__(self, other):
return not self.__eq__(other)
# end FunctionField
class ParameterField:
"""Class representing a pseudo-field read from a function"""
def __init__(self, func):
self.mask = 0
self.sign = 0
self.func = func
def __str__(self):
return self.func
def str_extract(self):
return self.func + '(ctx)'
def __eq__(self, other):
return self.func == other.func
def __ne__(self, other):
return not self.__eq__(other)
# end ParameterField
class Arguments:
"""Class representing the extracted fields of a format"""
def __init__(self, nm, flds, types, extern):
self.name = nm
self.extern = extern
self.fields = flds
self.types = types
def __str__(self):
return self.name + ' ' + str(self.fields)
def struct_name(self):
return 'arg_' + self.name
def output_def(self):
if not self.extern:
output('typedef struct {\n')
for (n, t) in zip(self.fields, self.types):
output(f' {t} {n};\n')
output('} ', self.struct_name(), ';\n\n')
# end Arguments
class General:
"""Common code between instruction formats and instruction patterns"""
def __init__(self, name, lineno, base, fixb, fixm, udfm, fldm, flds, w):
self.name = name
self.file = input_file
self.lineno = lineno
self.base = base
self.fixedbits = fixb
self.fixedmask = fixm
self.undefmask = udfm
self.fieldmask = fldm
self.fields = flds
self.width = w
def __str__(self):
return self.name + ' ' + str_match_bits(self.fixedbits, self.fixedmask)
def str1(self, i):
return str_indent(i) + self.__str__()
# end General
class Format(General):
"""Class representing an instruction format"""
def extract_name(self):
global decode_function
return decode_function + '_extract_' + self.name
def output_extract(self):
output('static void ', self.extract_name(), '(DisasContext *ctx, ',
self.base.struct_name(), ' *a, ', insntype, ' insn)\n{\n')
for n, f in self.fields.items():
output(' a->', n, ' = ', f.str_extract(), ';\n')
output('}\n\n')
# end Format
class Pattern(General):
"""Class representing an instruction pattern"""
def output_decl(self):
global translate_scope
global translate_prefix
output('typedef ', self.base.base.struct_name(),
' arg_', self.name, ';\n')
output(translate_scope, 'bool ', translate_prefix, '_', self.name,
'(DisasContext *ctx, arg_', self.name, ' *a);\n')
def output_code(self, i, extracted, outerbits, outermask):
global translate_prefix
ind = str_indent(i)
arg = self.base.base.name
output(ind, '/* ', self.file, ':', str(self.lineno), ' */\n')
if not extracted:
output(ind, self.base.extract_name(),
'(ctx, &u.f_', arg, ', insn);\n')
for n, f in self.fields.items():
output(ind, 'u.f_', arg, '.', n, ' = ', f.str_extract(), ';\n')
output(ind, 'if (', translate_prefix, '_', self.name,
'(ctx, &u.f_', arg, ')) return true;\n')
# Normal patterns do not have children.
def build_tree(self):
return
def prop_masks(self):
return
def prop_format(self):
return
def prop_width(self):
return
# end Pattern
class MultiPattern(General):
"""Class representing a set of instruction patterns"""
def __init__(self, lineno):
self.file = input_file
self.lineno = lineno
self.pats = []
self.base = None
self.fixedbits = 0
self.fixedmask = 0
self.undefmask = 0
self.width = None
def __str__(self):
r = 'group'
if self.fixedbits is not None:
r += ' ' + str_match_bits(self.fixedbits, self.fixedmask)
return r
def output_decl(self):
for p in self.pats:
p.output_decl()
def prop_masks(self):
global insnmask
fixedmask = insnmask
undefmask = insnmask
# Collect fixedmask/undefmask for all of the children.
for p in self.pats:
p.prop_masks()
fixedmask &= p.fixedmask
undefmask &= p.undefmask
# Widen fixedmask until all fixedbits match
repeat = True
fixedbits = 0
while repeat and fixedmask != 0:
fixedbits = None
for p in self.pats:
thisbits = p.fixedbits & fixedmask
if fixedbits is None:
fixedbits = thisbits
elif fixedbits != thisbits:
fixedmask &= ~(fixedbits ^ thisbits)
break
else:
repeat = False
self.fixedbits = fixedbits
self.fixedmask = fixedmask
self.undefmask = undefmask
def build_tree(self):
for p in self.pats:
p.build_tree()
def prop_format(self):
for p in self.pats:
p.build_tree()
def prop_width(self):
width = None
for p in self.pats:
p.prop_width()
if width is None:
width = p.width
elif width != p.width:
error_with_file(self.file, self.lineno,
'width mismatch in patterns within braces')
self.width = width
# end MultiPattern
class IncMultiPattern(MultiPattern):
"""Class representing an overlapping set of instruction patterns"""
def output_code(self, i, extracted, outerbits, outermask):
global translate_prefix
ind = str_indent(i)
for p in self.pats:
if outermask != p.fixedmask:
innermask = p.fixedmask & ~outermask
innerbits = p.fixedbits & ~outermask
output(ind, f'if ((insn & {whexC(innermask)}) == {whexC(innerbits)}) {{\n')
output(ind, f' /* {str_match_bits(p.fixedbits, p.fixedmask)} */\n')
p.output_code(i + 4, extracted, p.fixedbits, p.fixedmask)
output(ind, '}\n')
else:
p.output_code(i, extracted, p.fixedbits, p.fixedmask)
#end IncMultiPattern
class Tree:
"""Class representing a node in a decode tree"""
def __init__(self, fm, tm):
self.fixedmask = fm
self.thismask = tm
self.subs = []
self.base = None
def str1(self, i):
ind = str_indent(i)
r = ind + whex(self.fixedmask)
if self.format:
r += ' ' + self.format.name
r += ' [\n'
for (b, s) in self.subs:
r += ind + f' {whex(b)}:\n'
r += s.str1(i + 4) + '\n'
r += ind + ']'
return r
def __str__(self):
return self.str1(0)
def output_code(self, i, extracted, outerbits, outermask):
ind = str_indent(i)
# If we identified all nodes below have the same format,
# extract the fields now.
if not extracted and self.base:
output(ind, self.base.extract_name(),
'(ctx, &u.f_', self.base.base.name, ', insn);\n')
extracted = True
# Attempt to aid the compiler in producing compact switch statements.
# If the bits in the mask are contiguous, extract them.
sh = is_contiguous(self.thismask)
if sh > 0:
# Propagate SH down into the local functions.
def str_switch(b, sh=sh):
return f'(insn >> {sh}) & {b >> sh:#x}'
def str_case(b, sh=sh):
return hex(b >> sh)
else:
def str_switch(b):
return f'insn & {whexC(b)}'
def str_case(b):
return whexC(b)
output(ind, 'switch (', str_switch(self.thismask), ') {\n')
for b, s in sorted(self.subs):
assert (self.thismask & ~s.fixedmask) == 0
innermask = outermask | self.thismask
innerbits = outerbits | b
output(ind, 'case ', str_case(b), ':\n')
output(ind, ' /* ',
str_match_bits(innerbits, innermask), ' */\n')
s.output_code(i + 4, extracted, innerbits, innermask)
output(ind, ' break;\n')
output(ind, '}\n')
# end Tree
class ExcMultiPattern(MultiPattern):
"""Class representing a non-overlapping set of instruction patterns"""
def output_code(self, i, extracted, outerbits, outermask):
# Defer everything to our decomposed Tree node
self.tree.output_code(i, extracted, outerbits, outermask)
@staticmethod
def __build_tree(pats, outerbits, outermask):
# Find the intersection of all remaining fixedmask.
innermask = ~outermask & insnmask
for i in pats:
innermask &= i.fixedmask
if innermask == 0:
# Edge condition: One pattern covers the entire insnmask
if len(pats) == 1:
t = Tree(outermask, innermask)
t.subs.append((0, pats[0]))
return t
text = 'overlapping patterns:'
for p in pats:
text += '\n' + p.file + ':' + str(p.lineno) + ': ' + str(p)
error_with_file(pats[0].file, pats[0].lineno, text)
fullmask = outermask | innermask
# Sort each element of pats into the bin selected by the mask.
bins = {}
for i in pats:
fb = i.fixedbits & innermask
if fb in bins:
bins[fb].append(i)
else:
bins[fb] = [i]
# We must recurse if any bin has more than one element or if
# the single element in the bin has not been fully matched.
t = Tree(fullmask, innermask)
for b, l in bins.items():
s = l[0]
if len(l) > 1 or s.fixedmask & ~fullmask != 0:
s = ExcMultiPattern.__build_tree(l, b | outerbits, fullmask)
t.subs.append((b, s))
return t
def build_tree(self):
super().prop_format()
self.tree = self.__build_tree(self.pats, self.fixedbits,
self.fixedmask)
@staticmethod
def __prop_format(tree):
"""Propagate Format objects into the decode tree"""
# Depth first search.
for (b, s) in tree.subs:
if isinstance(s, Tree):
ExcMultiPattern.__prop_format(s)
# If all entries in SUBS have the same format, then
# propagate that into the tree.
f = None
for (b, s) in tree.subs:
if f is None:
f = s.base
if f is None:
return
if f is not s.base:
return
tree.base = f
def prop_format(self):
super().prop_format()
self.__prop_format(self.tree)
# end ExcMultiPattern
def parse_field(lineno, name, toks):
"""Parse one instruction field from TOKS at LINENO"""
global fields
global insnwidth
# A "simple" field will have only one entry;
# a "multifield" will have several.
subs = []
width = 0
func = None
for t in toks:
if re.match('^!function=', t):
if func:
error(lineno, 'duplicate function')
func = t.split('=')
func = func[1]
continue
if re.fullmatch('[0-9]+:s[0-9]+', t):
# Signed field extract
subtoks = t.split(':s')
sign = True
elif re.fullmatch('[0-9]+:[0-9]+', t):
# Unsigned field extract
subtoks = t.split(':')
sign = False
else:
error(lineno, f'invalid field token "{t}"')
po = int(subtoks[0])
le = int(subtoks[1])
if po + le > insnwidth:
error(lineno, f'field {t} too large')
f = Field(sign, po, le)
subs.append(f)
width += le
if width > insnwidth:
error(lineno, 'field too large')
if len(subs) == 0:
if func:
f = ParameterField(func)
else:
error(lineno, 'field with no value')
else:
if len(subs) == 1:
f = subs[0]
else:
mask = 0
for s in subs:
if mask & s.mask:
error(lineno, 'field components overlap')
mask |= s.mask
f = MultiField(subs, mask)
if func:
f = FunctionField(func, f)
if name in fields:
error(lineno, 'duplicate field', name)
fields[name] = f
# end parse_field
def parse_arguments(lineno, name, toks):
"""Parse one argument set from TOKS at LINENO"""
global arguments
global re_C_ident
global anyextern
flds = []
types = []
extern = False
for n in toks:
if re.fullmatch('!extern', n):
extern = True
anyextern = True
continue
if re.fullmatch(re_C_ident + ':' + re_C_ident, n):
(n, t) = n.split(':')
elif re.fullmatch(re_C_ident, n):
t = 'int'
else:
error(lineno, f'invalid argument set token "{n}"')
if n in flds:
error(lineno, f'duplicate argument "{n}"')
flds.append(n)
types.append(t)
if name in arguments:
error(lineno, 'duplicate argument set', name)
arguments[name] = Arguments(name, flds, types, extern)
# end parse_arguments
def lookup_field(lineno, name):
global fields
if name in fields:
return fields[name]
error(lineno, 'undefined field', name)
def add_field(lineno, flds, new_name, f):
if new_name in flds:
error(lineno, 'duplicate field', new_name)
flds[new_name] = f
return flds
def add_field_byname(lineno, flds, new_name, old_name):
return add_field(lineno, flds, new_name, lookup_field(lineno, old_name))
def infer_argument_set(flds):
global arguments
global decode_function
for arg in arguments.values():
if eq_fields_for_args(flds, arg):
return arg
name = decode_function + str(len(arguments))
arg = Arguments(name, flds.keys(), ['int'] * len(flds), False)
arguments[name] = arg
return arg
def infer_format(arg, fieldmask, flds, width):
global arguments
global formats
global decode_function
const_flds = {}
var_flds = {}
for n, c in flds.items():
if c is ConstField:
const_flds[n] = c
else:
var_flds[n] = c
# Look for an existing format with the same argument set and fields
for fmt in formats.values():
if arg and fmt.base != arg:
continue
if fieldmask != fmt.fieldmask:
continue
if width != fmt.width:
continue
if not eq_fields_for_fmts(flds, fmt.fields):
continue
return (fmt, const_flds)
name = decode_function + '_Fmt_' + str(len(formats))
if not arg:
arg = infer_argument_set(flds)
fmt = Format(name, 0, arg, 0, 0, 0, fieldmask, var_flds, width)
formats[name] = fmt
return (fmt, const_flds)
# end infer_format
def parse_generic(lineno, parent_pat, name, toks):
"""Parse one instruction format from TOKS at LINENO"""
global fields
global arguments
global formats
global allpatterns
global re_arg_ident
global re_fld_ident
global re_fmt_ident
global re_C_ident
global insnwidth
global insnmask
global variablewidth
is_format = parent_pat is None
fixedmask = 0
fixedbits = 0
undefmask = 0
width = 0
flds = {}
arg = None
fmt = None
for t in toks:
# '&Foo' gives a format an explicit argument set.
if re.fullmatch(re_arg_ident, t):
tt = t[1:]
if arg:
error(lineno, 'multiple argument sets')
if tt in arguments:
arg = arguments[tt]
else:
error(lineno, 'undefined argument set', t)
continue
# '@Foo' gives a pattern an explicit format.
if re.fullmatch(re_fmt_ident, t):
tt = t[1:]
if fmt:
error(lineno, 'multiple formats')
if tt in formats:
fmt = formats[tt]
else:
error(lineno, 'undefined format', t)
continue
# '%Foo' imports a field.
if re.fullmatch(re_fld_ident, t):
tt = t[1:]
flds = add_field_byname(lineno, flds, tt, tt)
continue
# 'Foo=%Bar' imports a field with a different name.
if re.fullmatch(re_C_ident + '=' + re_fld_ident, t):
(fname, iname) = t.split('=%')
flds = add_field_byname(lineno, flds, fname, iname)
continue
# 'Foo=number' sets an argument field to a constant value
if re.fullmatch(re_C_ident + '=[+-]?[0-9]+', t):
(fname, value) = t.split('=')
value = int(value)
flds = add_field(lineno, flds, fname, ConstField(value))
continue
# Pattern of 0s, 1s, dots and dashes indicate required zeros,
# required ones, or dont-cares.
if re.fullmatch('[01.-]+', t):
shift = len(t)
fms = t.replace('0', '1')
fms = fms.replace('.', '0')
fms = fms.replace('-', '0')
fbs = t.replace('.', '0')
fbs = fbs.replace('-', '0')
ubm = t.replace('1', '0')
ubm = ubm.replace('.', '0')
ubm = ubm.replace('-', '1')
fms = int(fms, 2)
fbs = int(fbs, 2)
ubm = int(ubm, 2)
fixedbits = (fixedbits << shift) | fbs
fixedmask = (fixedmask << shift) | fms
undefmask = (undefmask << shift) | ubm
# Otherwise, fieldname:fieldwidth
elif re.fullmatch(re_C_ident + ':s?[0-9]+', t):
(fname, flen) = t.split(':')
sign = False
if flen[0] == 's':
sign = True
flen = flen[1:]
shift = int(flen, 10)
if shift + width > insnwidth:
error(lineno, f'field {fname} exceeds insnwidth')
f = Field(sign, insnwidth - width - shift, shift)
flds = add_field(lineno, flds, fname, f)
fixedbits <<= shift
fixedmask <<= shift
undefmask <<= shift
else:
error(lineno, f'invalid token "{t}"')
width += shift
if variablewidth and width < insnwidth and width % 8 == 0:
shift = insnwidth - width
fixedbits <<= shift
fixedmask <<= shift
undefmask <<= shift
undefmask |= (1 << shift) - 1
# We should have filled in all of the bits of the instruction.
elif not (is_format and width == 0) and width != insnwidth:
error(lineno, f'definition has {width} bits')
# Do not check for fields overlapping fields; one valid usage
# is to be able to duplicate fields via import.
fieldmask = 0
for f in flds.values():
fieldmask |= f.mask
# Fix up what we've parsed to match either a format or a pattern.
if is_format:
# Formats cannot reference formats.
if fmt:
error(lineno, 'format referencing format')
# If an argument set is given, then there should be no fields
# without a place to store it.
if arg:
for f in flds.keys():
if f not in arg.fields:
error(lineno, f'field {f} not in argument set {arg.name}')
else:
arg = infer_argument_set(flds)
if name in formats:
error(lineno, 'duplicate format name', name)
fmt = Format(name, lineno, arg, fixedbits, fixedmask,
undefmask, fieldmask, flds, width)
formats[name] = fmt
else:
# Patterns can reference a format ...
if fmt:
# ... but not an argument simultaneously
if arg:
error(lineno, 'pattern specifies both format and argument set')
if fixedmask & fmt.fixedmask:
error(lineno, 'pattern fixed bits overlap format fixed bits')
if width != fmt.width:
error(lineno, 'pattern uses format of different width')
fieldmask |= fmt.fieldmask
fixedbits |= fmt.fixedbits
fixedmask |= fmt.fixedmask
undefmask |= fmt.undefmask
else:
(fmt, flds) = infer_format(arg, fieldmask, flds, width)
arg = fmt.base
for f in flds.keys():
if f not in arg.fields:
error(lineno, f'field {f} not in argument set {arg.name}')
if f in fmt.fields.keys():
error(lineno, f'field {f} set by format and pattern')
for f in arg.fields:
if f not in flds.keys() and f not in fmt.fields.keys():
error(lineno, f'field {f} not initialized')
pat = Pattern(name, lineno, fmt, fixedbits, fixedmask,
undefmask, fieldmask, flds, width)
parent_pat.pats.append(pat)
allpatterns.append(pat)
# Validate the masks that we have assembled.
if fieldmask & fixedmask:
error(lineno, 'fieldmask overlaps fixedmask ',
f'({whex(fieldmask)} & {whex(fixedmask)})')
if fieldmask & undefmask:
error(lineno, 'fieldmask overlaps undefmask ',
f'({whex(fieldmask)} & {whex(undefmask)})')
if fixedmask & undefmask:
error(lineno, 'fixedmask overlaps undefmask ',
f'({whex(fixedmask)} & {whex(undefmask)})')
if not is_format:
allbits = fieldmask | fixedmask | undefmask
if allbits != insnmask:
error(lineno, 'bits left unspecified ',
f'({whex(allbits ^ insnmask)})')
# end parse_general
def parse_file(f, parent_pat):
"""Parse all of the patterns within a file"""
global re_arg_ident
global re_fld_ident
global re_fmt_ident
global re_pat_ident
# Read all of the lines of the file. Concatenate lines
# ending in backslash; discard empty lines and comments.
toks = []
lineno = 0
nesting = 0
nesting_pats = []
for line in f:
lineno += 1
# Expand and strip spaces, to find indent.
line = line.rstrip()
line = line.expandtabs()
len1 = len(line)
line = line.lstrip()
len2 = len(line)
# Discard comments
end = line.find('#')
if end >= 0:
line = line[:end]
t = line.split()
if len(toks) != 0:
# Next line after continuation
toks.extend(t)
else:
# Allow completely blank lines.
if len1 == 0:
continue
indent = len1 - len2
# Empty line due to comment.
if len(t) == 0:
# Indentation must be correct, even for comment lines.
if indent != nesting:
error(lineno, 'indentation ', indent, ' != ', nesting)
continue
start_lineno = lineno
toks = t
# Continuation?
if toks[-1] == '\\':
toks.pop()
continue
name = toks[0]
del toks[0]
# End nesting?
if name == '}' or name == ']':
if len(toks) != 0:
error(start_lineno, 'extra tokens after close brace')
# Make sure { } and [ ] nest properly.
if (name == '}') != isinstance(parent_pat, IncMultiPattern):
error(lineno, 'mismatched close brace')
try:
parent_pat = nesting_pats.pop()
except:
error(lineno, 'extra close brace')
nesting -= 2
if indent != nesting:
error(lineno, 'indentation ', indent, ' != ', nesting)
toks = []
continue
# Everything else should have current indentation.
if indent != nesting:
error(start_lineno, 'indentation ', indent, ' != ', nesting)
# Start nesting?
if name == '{' or name == '[':
if len(toks) != 0:
error(start_lineno, 'extra tokens after open brace')
if name == '{':
nested_pat = IncMultiPattern(start_lineno)
else:
nested_pat = ExcMultiPattern(start_lineno)
parent_pat.pats.append(nested_pat)
nesting_pats.append(parent_pat)
parent_pat = nested_pat
nesting += 2
toks = []
continue
# Determine the type of object needing to be parsed.
if re.fullmatch(re_fld_ident, name):
parse_field(start_lineno, name[1:], toks)
elif re.fullmatch(re_arg_ident, name):
parse_arguments(start_lineno, name[1:], toks)
elif re.fullmatch(re_fmt_ident, name):
parse_generic(start_lineno, None, name[1:], toks)
elif re.fullmatch(re_pat_ident, name):
parse_generic(start_lineno, parent_pat, name, toks)
else:
error(lineno, f'invalid token "{name}"')
toks = []
if nesting != 0:
error(lineno, 'missing close brace')
# end parse_file
class SizeTree:
"""Class representing a node in a size decode tree"""
def __init__(self, m, w):
self.mask = m
self.subs = []
self.base = None
self.width = w
def str1(self, i):
ind = str_indent(i)
r = ind + whex(self.mask) + ' [\n'
for (b, s) in self.subs:
r += ind + f' {whex(b)}:\n'
r += s.str1(i + 4) + '\n'
r += ind + ']'
return r
def __str__(self):
return self.str1(0)
def output_code(self, i, extracted, outerbits, outermask):
ind = str_indent(i)
# If we need to load more bytes to test, do so now.
if extracted < self.width:
output(ind, f'insn = {decode_function}_load_bytes',
f'(ctx, insn, {extracted // 8}, {self.width // 8});\n')
extracted = self.width
# Attempt to aid the compiler in producing compact switch statements.
# If the bits in the mask are contiguous, extract them.
sh = is_contiguous(self.mask)
if sh > 0:
# Propagate SH down into the local functions.
def str_switch(b, sh=sh):
return f'(insn >> {sh}) & {b >> sh:#x}'
def str_case(b, sh=sh):
return hex(b >> sh)
else:
def str_switch(b):
return f'insn & {whexC(b)}'
def str_case(b):
return whexC(b)
output(ind, 'switch (', str_switch(self.mask), ') {\n')
for b, s in sorted(self.subs):
innermask = outermask | self.mask
innerbits = outerbits | b
output(ind, 'case ', str_case(b), ':\n')
output(ind, ' /* ',
str_match_bits(innerbits, innermask), ' */\n')
s.output_code(i + 4, extracted, innerbits, innermask)
output(ind, '}\n')
output(ind, 'return insn;\n')
# end SizeTree
class SizeLeaf:
"""Class representing a leaf node in a size decode tree"""
def __init__(self, m, w):
self.mask = m
self.width = w
def str1(self, i):
return str_indent(i) + whex(self.mask)
def __str__(self):
return self.str1(0)
def output_code(self, i, extracted, outerbits, outermask):
global decode_function
ind = str_indent(i)
# If we need to load more bytes, do so now.
if extracted < self.width:
output(ind, f'insn = {decode_function}_load_bytes',
f'(ctx, insn, {extracted // 8}, {self.width // 8});\n')
extracted = self.width
output(ind, 'return insn;\n')
# end SizeLeaf
def build_size_tree(pats, width, outerbits, outermask):
global insnwidth
# Collect the mask of bits that are fixed in this width
innermask = 0xff << (insnwidth - width)
innermask &= ~outermask
minwidth = None
onewidth = True
for i in pats:
innermask &= i.fixedmask
if minwidth is None:
minwidth = i.width
elif minwidth != i.width:
onewidth = False;
if minwidth < i.width:
minwidth = i.width
if onewidth:
return SizeLeaf(innermask, minwidth)
if innermask == 0:
if width < minwidth:
return build_size_tree(pats, width + 8, outerbits, outermask)
pnames = []
for p in pats:
pnames.append(p.name + ':' + p.file + ':' + str(p.lineno))
error_with_file(pats[0].file, pats[0].lineno,
f'overlapping patterns size {width}:', pnames)
bins = {}
for i in pats:
fb = i.fixedbits & innermask
if fb in bins:
bins[fb].append(i)
else:
bins[fb] = [i]
fullmask = outermask | innermask
lens = sorted(bins.keys())
if len(lens) == 1:
b = lens[0]
return build_size_tree(bins[b], width + 8, b | outerbits, fullmask)
r = SizeTree(innermask, width)
for b, l in bins.items():
s = build_size_tree(l, width, b | outerbits, fullmask)
r.subs.append((b, s))
return r
# end build_size_tree
def prop_size(tree):
"""Propagate minimum widths up the decode size tree"""
if isinstance(tree, SizeTree):
min = None
for (b, s) in tree.subs:
width = prop_size(s)
if min is None or min > width:
min = width
assert min >= tree.width
tree.width = min
else:
min = tree.width
return min
# end prop_size
def main():
global arguments
global formats
global allpatterns
global translate_scope
global translate_prefix
global output_fd
global output_file
global input_file
global insnwidth
global insntype
global insnmask
global decode_function
global bitop_width
global variablewidth
global anyextern
decode_scope = 'static '
long_opts = ['decode=', 'translate=', 'output=', 'insnwidth=',
'static-decode=', 'varinsnwidth=']
try:
(opts, args) = getopt.gnu_getopt(sys.argv[1:], 'o:vw:', long_opts)
except getopt.GetoptError as err:
error(0, err)
for o, a in opts:
if o in ('-o', '--output'):
output_file = a
elif o == '--decode':
decode_function = a
decode_scope = ''
elif o == '--static-decode':
decode_function = a
elif o == '--translate':
translate_prefix = a
translate_scope = ''
elif o in ('-w', '--insnwidth', '--varinsnwidth'):
if o == '--varinsnwidth':
variablewidth = True
insnwidth = int(a)
if insnwidth == 16:
insntype = 'uint16_t'
insnmask = 0xffff
elif insnwidth == 64:
insntype = 'uint64_t'
insnmask = 0xffffffffffffffff
bitop_width = 64
elif insnwidth != 32:
error(0, 'cannot handle insns of width', insnwidth)
else:
assert False, 'unhandled option'
if len(args) < 1:
error(0, 'missing input file')
toppat = ExcMultiPattern(0)
for filename in args:
input_file = filename
f = open(filename, 'rt', encoding='utf-8')
parse_file(f, toppat)
f.close()
# We do not want to compute masks for toppat, because those masks
# are used as a starting point for build_tree. For toppat, we must
# insist that decode begins from naught.
for i in toppat.pats:
i.prop_masks()
toppat.build_tree()
toppat.prop_format()
if variablewidth:
for i in toppat.pats:
i.prop_width()
stree = build_size_tree(toppat.pats, 8, 0, 0)
prop_size(stree)
if output_file:
output_fd = open(output_file, 'wt', encoding='utf-8')
else:
output_fd = io.TextIOWrapper(sys.stdout.buffer,
encoding=sys.stdout.encoding,
errors="ignore")
output_autogen()
for n in sorted(arguments.keys()):
f = arguments[n]
f.output_def()
# A single translate function can be invoked for different patterns.
# Make sure that the argument sets are the same, and declare the
# function only once.
#
# If we're sharing formats, we're likely also sharing trans_* functions,
# but we can't tell which ones. Prevent issues from the compiler by
# suppressing redundant declaration warnings.
if anyextern:
output("#pragma GCC diagnostic push\n",
"#pragma GCC diagnostic ignored \"-Wredundant-decls\"\n",
"#ifdef __clang__\n"
"# pragma GCC diagnostic ignored \"-Wtypedef-redefinition\"\n",
"#endif\n\n")
out_pats = {}
for i in allpatterns:
if i.name in out_pats:
p = out_pats[i.name]
if i.base.base != p.base.base:
error(0, i.name, ' has conflicting argument sets')
else:
i.output_decl()
out_pats[i.name] = i
output('\n')
if anyextern:
output("#pragma GCC diagnostic pop\n\n")
for n in sorted(formats.keys()):
f = formats[n]
f.output_extract()
output(decode_scope, 'bool ', decode_function,
'(DisasContext *ctx, ', insntype, ' insn)\n{\n')
i4 = str_indent(4)
if len(allpatterns) != 0:
output(i4, 'union {\n')
for n in sorted(arguments.keys()):
f = arguments[n]
output(i4, i4, f.struct_name(), ' f_', f.name, ';\n')
output(i4, '} u;\n\n')
toppat.output_code(4, False, 0, 0)
output(i4, 'return false;\n')
output('}\n')
if variablewidth:
output('\n', decode_scope, insntype, ' ', decode_function,
'_load(DisasContext *ctx)\n{\n',
' ', insntype, ' insn = 0;\n\n')
stree.output_code(4, 0, 0, 0)
output('}\n')
if output_file:
output_fd.close()
# end main
if __name__ == '__main__':
main()