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c4749e70d4
within a single bit-width of vectors. This is particularly useful for when you know you have bugs in a certain area and want to find simpler test cases than those produced by an open-ended fuzzing that ends up legalizing the vector in addition to shuffling it. llvm-svn: 215056
185 lines
6.4 KiB
Python
Executable File
185 lines
6.4 KiB
Python
Executable File
#!/usr/bin/env python
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"""A shuffle vector fuzz tester.
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This is a python program to fuzz test the LLVM shufflevector instruction. It
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generates a function with a random sequnece of shufflevectors, maintaining the
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element mapping accumulated across the function. It then generates a main
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function which calls it with a different value in each element and checks that
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the result matches the expected mapping.
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Take the output IR printed to stdout, compile it to an executable using whatever
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set of transforms you want to test, and run the program. If it crashes, it found
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a bug.
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"""
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import argparse
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import itertools
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import random
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import sys
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def main():
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parser = argparse.ArgumentParser(description=__doc__)
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parser.add_argument('seed',
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help='A string used to seed the RNG')
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parser.add_argument('-v', '--verbose', action='store_true',
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help='Show verbose output')
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parser.add_argument('--fixed-num-shuffles', type=int,
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help='Specify a fixed number of shuffles to test')
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parser.add_argument('--fixed-bit-width', type=int, choices=[128, 256],
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help='Specify a fixed bit width of vector to test')
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parser.add_argument('--triple',
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help='Specify a triple string to include in the IR')
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args = parser.parse_args()
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random.seed(args.seed)
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if args.fixed_bit_width is not None:
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if args.fixed_bit_width == 128:
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(width, element_type) = random.choice(
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[(2, 'i64'), (4, 'i32'), (8, 'i16'), (16, 'i8'),
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(2, 'f64'), (4, 'f32')])
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elif args.fixed_bit_width == 256:
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(width, element_type) = random.choice([
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(4, 'i64'), (8, 'i32'), (16, 'i16'), (32, 'i8'),
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(4, 'f64'), (8, 'f32')])
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else:
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sys.exit(1) # Checked above by argument parsing.
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else:
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width = random.choice([2, 4, 8, 16, 32, 64])
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element_type = random.choice(['i8', 'i16', 'i32', 'i64', 'f32', 'f64'])
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# FIXME: Support blends.
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shuffle_indices = [-1] + range(width)
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if args.fixed_num_shuffles is not None:
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num_shuffles = args.fixed_num_shuffles
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else:
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num_shuffles = random.randint(0, 16)
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shuffles = [[random.choice(shuffle_indices)
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for _ in itertools.repeat(None, width)]
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for _ in itertools.repeat(None, num_shuffles)]
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if args.verbose:
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# Print out the shuffle sequence in a compact form.
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print >>sys.stderr, 'Testing shuffle sequence:'
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for s in shuffles:
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print >>sys.stderr, ' v%d%s: %s' % (width, element_type, s)
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print >>sys.stderr, ''
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# Compute a round-trip of the shuffle.
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result = range(1, width + 1)
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for s in shuffles:
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result = [result[i] if i != -1 else -1 for i in s]
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if args.verbose:
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print >>sys.stderr, 'Which transforms:'
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print >>sys.stderr, ' from: %s' % (range(1, width + 1),)
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print >>sys.stderr, ' into: %s' % (result,)
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print >>sys.stderr, ''
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# The IR uses silly names for floating point types. We also need a same-size
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# integer type.
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integral_element_type = element_type
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if element_type == 'f32':
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integral_element_type = 'i32'
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element_type = 'float'
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elif element_type == 'f64':
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integral_element_type = 'i64'
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element_type = 'double'
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# Now we need to generate IR for the shuffle function.
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subst = {'N': width, 'T': element_type, 'IT': integral_element_type}
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print """
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define internal <%(N)d x %(T)s> @test(<%(N)d x %(T)s> %%v) noinline nounwind {
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entry:""" % subst
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for i, s in enumerate(shuffles):
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print """
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%%s%(i)d = shufflevector <%(N)d x %(T)s> %(I)s, <%(N)d x %(T)s> undef, <%(N)d x i32> <%(S)s>
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""".strip() % dict(subst,
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i=i,
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I=('%%s%d' % (i - 1)) if i != 0 else '%v',
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S=', '.join(['i32 %s' % (str(si) if si != -1 else 'undef',)
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for si in s]))
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print """
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ret <%(N)d x %(T)s> %%s%(i)d
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}
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""" % dict(subst, i=len(shuffles) - 1)
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# Generate some string constants that we can use to report errors.
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for i, r in enumerate(result):
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if r != -1:
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s = ('FAIL(%(seed)s): lane %(lane)d, expected %(result)d, found %%d\\0A' %
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{'seed': args.seed, 'lane': i, 'result': r})
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s += ''.join(['\\00' for _ in itertools.repeat(None, 64 - len(s) + 2)])
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print """
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@error.%(i)d = private unnamed_addr global [64 x i8] c"%(s)s"
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""".strip() % {'i': i, 's': s}
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# Finally, generate a main function which will trap if any lanes are mapped
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# incorrectly (in an observable way).
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print """
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define i32 @main() optnone noinline {
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entry:
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; Create a scratch space to print error messages.
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%%str = alloca [64 x i8]
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%%str.ptr = getelementptr inbounds [64 x i8]* %%str, i32 0, i32 0
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; Build the input vector and call the test function.
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%%input = bitcast <%(N)d x %(IT)s> <%(input)s> to <%(N)d x %(T)s>
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%%v = call <%(N)d x %(T)s> @test(<%(N)d x %(T)s> %%input)
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; We need to cast this back to an integer type vector to easily check the
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; result.
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%%v.cast = bitcast <%(N)d x %(T)s> %%v to <%(N)d x %(IT)s>
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br label %%test.0
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""" % dict(subst,
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input=', '.join(['%(IT)s %(i)s' % dict(subst, i=i)
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for i in xrange(1, width + 1)]),
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result=', '.join(['%(IT)s %(i)s' % dict(subst,
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i=i if i != -1 else 'undef')
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for i in result]))
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# Test that each non-undef result lane contains the expected value.
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for i, r in enumerate(result):
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if r == -1:
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print """
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test.%(i)d:
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; Skip this lane, its value is undef.
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br label %%test.%(next_i)d
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""" % dict(subst, i=i, next_i=i + 1)
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else:
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print """
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test.%(i)d:
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%%v.%(i)d = extractelement <%(N)d x %(IT)s> %%v.cast, i32 %(i)d
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%%cmp.%(i)d = icmp ne %(IT)s %%v.%(i)d, %(r)d
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br i1 %%cmp.%(i)d, label %%die.%(i)d, label %%test.%(next_i)d
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die.%(i)d:
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; Capture the actual value and print an error message.
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%%tmp.%(i)d = zext %(IT)s %%v.%(i)d to i2048
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%%bad.%(i)d = trunc i2048 %%tmp.%(i)d to i32
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call i32 (i8*, i8*, ...)* @sprintf(i8* %%str.ptr, i8* getelementptr inbounds ([64 x i8]* @error.%(i)d, i32 0, i32 0), i32 %%bad.%(i)d)
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%%length.%(i)d = call i32 @strlen(i8* %%str.ptr)
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%%size.%(i)d = add i32 %%length.%(i)d, 1
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call i32 @write(i32 2, i8* %%str.ptr, i32 %%size.%(i)d)
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call void @llvm.trap()
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unreachable
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""" % dict(subst, i=i, next_i=i + 1, r=r)
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print """
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test.%d:
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ret i32 0
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}
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declare i32 @strlen(i8*)
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declare i32 @write(i32, i8*, i32)
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declare i32 @sprintf(i8*, i8*, ...)
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declare void @llvm.trap() noreturn nounwind
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""" % (len(result),)
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if __name__ == '__main__':
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main()
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