"""A shuffle vector fuzz tester.
This is a python program to fuzz test the LLVM shufflevector instruction. It
generates a function with a random sequnece of shufflevectors, maintaining the
element mapping accumulated across the function. It then generates a main
function which calls it with a different value in each element and checks that
the result matches the expected mapping.
Take the output IR printed to stdout, compile it to an executable using whatever
set of transforms you want to test, and run the program. If it crashes, it found
a bug.
"""
import argparse
import itertools
import random
import sys
import uuid
def main():
element_types=['i8', 'i16', 'i32', 'i64', 'f32', 'f64']
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument('-v', '--verbose', action='store_true',
help='Show verbose output')
parser.add_argument('--seed', default=str(uuid.uuid4()),
help='A string used to seed the RNG')
parser.add_argument('--max-shuffle-height', type=int, default=16,
help='Specify a fixed height of shuffle tree to test')
parser.add_argument('--no-blends', dest='blends', action='store_false',
help='Include blends of two input vectors')
parser.add_argument('--fixed-bit-width', type=int, choices=[128, 256],
help='Specify a fixed bit width of vector to test')
parser.add_argument('--fixed-element-type', choices=element_types,
help='Specify a fixed element type to test')
parser.add_argument('--triple',
help='Specify a triple string to include in the IR')
args = parser.parse_args()
random.seed(args.seed)
if args.fixed_element_type is not None:
element_types=[args.fixed_element_type]
if args.fixed_bit_width is not None:
if args.fixed_bit_width == 128:
width_map={'i64': 2, 'i32': 4, 'i16': 8, 'i8': 16, 'f64': 2, 'f32': 4}
(width, element_type) = random.choice(
[(width_map[t], t) for t in element_types])
elif args.fixed_bit_width == 256:
width_map={'i64': 4, 'i32': 8, 'i16': 16, 'i8': 32, 'f64': 4, 'f32': 8}
(width, element_type) = random.choice(
[(width_map[t], t) for t in element_types])
else:
sys.exit(1) else:
width = random.choice([2, 4, 8, 16, 32, 64])
element_type = random.choice(element_types)
element_modulus = {
'i8': 1 << 8, 'i16': 1 << 16, 'i32': 1 << 32, 'i64': 1 << 64,
'f32': 1 << 32, 'f64': 1 << 64}[element_type]
shuffle_range = (2 * width) if args.blends else width
A = float(shuffle_range)
C = float(args.max_shuffle_height)
undef_prob = 1.0 - (((A + 1.0) * pow(A, (C + 1.0)/C)) /
(A * pow(A + 1.0, (C + 1.0)/C)))
shuffle_tree = [[[-1 if random.random() <= undef_prob
else random.choice(range(shuffle_range))
for _ in itertools.repeat(None, width)]
for _ in itertools.repeat(None, args.max_shuffle_height - i)]
for i in xrange(args.max_shuffle_height)]
if args.verbose:
print >>sys.stderr, ('Testing shuffle sequence "%s" (v%d%s):' %
(args.seed, width, element_type))
for i, shuffles in enumerate(shuffle_tree):
print >>sys.stderr, ' tree level %d:' % (i,)
for j, s in enumerate(shuffles):
print >>sys.stderr, ' shuffle %d: %s' % (j, s)
print >>sys.stderr, ''
inputs = [[int(j % element_modulus)
for j in xrange(i * width + 1, (i + 1) * width + 1)]
for i in xrange(args.max_shuffle_height + 1)]
results = inputs
for shuffles in shuffle_tree:
results = [[((results[i] if j < width else results[i + 1])[j % width]
if j != -1 else -1)
for j in s]
for i, s in enumerate(shuffles)]
if len(results) != 1:
print >>sys.stderr, 'ERROR: Bad results: %s' % (results,)
sys.exit(1)
result = results[0]
if args.verbose:
print >>sys.stderr, 'Which transforms:'
print >>sys.stderr, ' from: %s' % (inputs,)
print >>sys.stderr, ' into: %s' % (result,)
print >>sys.stderr, ''
integral_element_type = element_type
if element_type == 'f32':
integral_element_type = 'i32'
element_type = 'float'
elif element_type == 'f64':
integral_element_type = 'i64'
element_type = 'double'
subst = {'N': width, 'T': element_type, 'IT': integral_element_type}
print """
define internal fastcc <%(N)d x %(T)s> @test(%(arguments)s) noinline nounwind {
entry:""" % dict(subst,
arguments=', '.join(
['<%(N)d x %(T)s> %%s.0.%(i)d' % dict(subst, i=i)
for i in xrange(args.max_shuffle_height + 1)]))
for i, shuffles in enumerate(shuffle_tree):
for j, s in enumerate(shuffles):
print """
%%s.%(next_i)d.%(j)d = shufflevector <%(N)d x %(T)s> %%s.%(i)d.%(j)d, <%(N)d x %(T)s> %%s.%(i)d.%(next_j)d, <%(N)d x i32> <%(S)s>
""".strip('\n') % dict(subst, i=i, next_i=i + 1, j=j, next_j=j + 1,
S=', '.join(['i32 ' + (str(si) if si != -1 else 'undef')
for si in s]))
print """
ret <%(N)d x %(T)s> %%s.%(i)d.0
}
""" % dict(subst, i=len(shuffle_tree))
for i, r in enumerate(result):
if r != -1:
s = ('FAIL(%(seed)s): lane %(lane)d, expected %(result)d, found %%d\\0A' %
{'seed': args.seed, 'lane': i, 'result': r})
s += ''.join(['\\00' for _ in itertools.repeat(None, 128 - len(s) + 2)])
print """
@error.%(i)d = private unnamed_addr global [128 x i8] c"%(s)s"
""".strip() % {'i': i, 's': s}
print """
define internal fastcc <%(N)d x %(T)s> @test_wrapper(%(arguments)s) optnone noinline {
%%result = call fastcc <%(N)d x %(T)s> @test(%(arguments)s)
ret <%(N)d x %(T)s> %%result
}
""" % dict(subst,
arguments=', '.join(['<%(N)d x %(T)s> %%s.%(i)d' % dict(subst, i=i)
for i in xrange(args.max_shuffle_height + 1)]))
print """
define i32 @main() {
entry:
; Create a scratch space to print error messages.
%%str = alloca [128 x i8]
%%str.ptr = getelementptr inbounds [128 x i8]* %%str, i32 0, i32 0
; Build the input vector and call the test function.
%%v = call fastcc <%(N)d x %(T)s> @test_wrapper(%(inputs)s)
; We need to cast this back to an integer type vector to easily check the
; result.
%%v.cast = bitcast <%(N)d x %(T)s> %%v to <%(N)d x %(IT)s>
br label %%test.0
""" % dict(subst,
inputs=', '.join(
[('<%(N)d x %(T)s> bitcast '
'(<%(N)d x %(IT)s> <%(input)s> to <%(N)d x %(T)s>)' %
dict(subst, input=', '.join(['%(IT)s %(i)d' % dict(subst, i=i)
for i in input])))
for input in inputs]))
for i, r in enumerate(result):
if r == -1:
print """
test.%(i)d:
; Skip this lane, its value is undef.
br label %%test.%(next_i)d
""" % dict(subst, i=i, next_i=i + 1)
else:
print """
test.%(i)d:
%%v.%(i)d = extractelement <%(N)d x %(IT)s> %%v.cast, i32 %(i)d
%%cmp.%(i)d = icmp ne %(IT)s %%v.%(i)d, %(r)d
br i1 %%cmp.%(i)d, label %%die.%(i)d, label %%test.%(next_i)d
die.%(i)d:
; Capture the actual value and print an error message.
%%tmp.%(i)d = zext %(IT)s %%v.%(i)d to i2048
%%bad.%(i)d = trunc i2048 %%tmp.%(i)d to i32
call i32 (i8*, i8*, ...)* @sprintf(i8* %%str.ptr, i8* getelementptr inbounds ([128 x i8]* @error.%(i)d, i32 0, i32 0), i32 %%bad.%(i)d)
%%length.%(i)d = call i32 @strlen(i8* %%str.ptr)
%%size.%(i)d = add i32 %%length.%(i)d, 1
call i32 @write(i32 2, i8* %%str.ptr, i32 %%size.%(i)d)
call void @llvm.trap()
unreachable
""" % dict(subst, i=i, next_i=i + 1, r=r)
print """
test.%d:
ret i32 0
}
declare i32 @strlen(i8*)
declare i32 @write(i32, i8*, i32)
declare i32 @sprintf(i8*, i8*, ...)
declare void @llvm.trap() noreturn nounwind
""" % (len(result),)
if __name__ == '__main__':
main()