llvm/utils/shuffle_select_fuzz_tester.py

   1 #!/usr/bin/env python
   2
   3 """A shuffle-select vector fuzz tester.
   4
   5 This is a python program to fuzz test the LLVM shufflevector and select
   6 instructions. It generates a function with a random sequnece of shufflevectors
   7 while optionally attaching it with a select instruction (regular or zero merge),
   8 maintaining the element mapping accumulated across the function. It then
   9 generates a main function which calls it with a different value in each element
  10 and checks that the result matches the expected mapping.
  11
  12 Take the output IR printed to stdout, compile it to an executable using whatever
  13 set of transforms you want to test, and run the program. If it crashes, it found
  14 a bug (an error message with the expected and actual result is printed).
  15 """
  16 from __future__ import print_function
  17
  18 import random
  19 import uuid
  20 import argparse
  21
  22 # Possibility of one undef index in generated mask for shufflevector instruction
  23 SHUF_UNDEF_POS = 0.15
  24
  25 # Possibility of one undef index in generated mask for select instruction
  26 SEL_UNDEF_POS = 0.15
  27
  28 # Possibility of adding a select instruction to the result of a shufflevector
  29 ADD_SEL_POS = 0.4
  30
  31 # If we are adding a select instruction, this is the possibility of a
  32 # merge-select instruction (1 - MERGE_SEL_POS = possibility of zero-merge-select
  33 # instruction.
  34 MERGE_SEL_POS = 0.5
  35
  36
  37 test_template = r"""
  38 define internal fastcc {ty} @test({inputs}) noinline nounwind {{
  39 entry:
  40 {instructions}
  41   ret {ty} {last_name}
  42 }}
  43 """
  44
  45 error_template = r'''@error.{lane} = private unnamed_addr global [64 x i8] c"FAIL: lane {lane}, expected {exp}, found %d\0A{padding}"'''
  46
  47 main_template = r"""
  48 define i32 @main() {{
  49 entry:
  50   ; Create a scratch space to print error messages.
  51   %str = alloca [64 x i8]
  52   %str.ptr = getelementptr inbounds [64 x i8], [64 x i8]* %str, i32 0, i32 0
  53
  54   ; Build the input vector and call the test function.
  55   %v = call fastcc {ty} @test({inputs})
  56   br label %test.0
  57
  58   {check_die}
  59 }}
  60
  61 declare i32 @strlen(i8*)
  62 declare i32 @write(i32, i8*, i32)
  63 declare i32 @sprintf(i8*, i8*, ...)
  64 declare void @llvm.trap() noreturn nounwind
  65 """
  66
  67 check_template = r"""
  68 test.{lane}:
  69   %v.{lane} = extractelement {ty} %v, i32 {lane}
  70   %cmp.{lane} = {i_f}cmp {ordered}ne {scalar_ty} %v.{lane}, {exp}
  71   br i1 %cmp.{lane}, label %die.{lane}, label %test.{n_lane}
  72 """
  73
  74 undef_check_template = r"""
  75 test.{lane}:
  76 ; Skip this lane, its value is undef.
  77   br label %test.{n_lane}
  78 """
  79
  80 die_template = r"""
  81 die.{lane}:
  82 ; Capture the actual value and print an error message.
  83   call i32 (i8*, i8*, ...) @sprintf(i8* %str.ptr, i8* getelementptr inbounds ([64 x i8], [64 x i8]* @error.{lane}, i32 0, i32 0), {scalar_ty} %v.{lane})
  84   %length.{lane} = call i32 @strlen(i8* %str.ptr)
  85   call i32 @write(i32 2, i8* %str.ptr, i32 %length.{lane})
  86   call void @llvm.trap()
  87   unreachable
  88 """
  89
  90
  91 class Type:
  92     def __init__(self, is_float, elt_width, elt_num):
  93         self.is_float = is_float  # Boolean
  94         self.elt_width = elt_width  # Integer
  95         self.elt_num = elt_num  # Integer
  96
  97     def dump(self):
  98         if self.is_float:
  99             str_elt = "float" if self.elt_width == 32 else "double"
 100         else:
 101             str_elt = "i" + str(self.elt_width)
 102
 103         if self.elt_num == 1:
 104             return str_elt
 105         else:
 106             return "<" + str(self.elt_num) + " x " + str_elt + ">"
 107
 108     def get_scalar_type(self):
 109         return Type(self.is_float, self.elt_width, 1)
 110
 111
 112 # Class to represent any value (variable) that can be used.
 113 class Value:
 114     def __init__(self, name, ty, value=None):
 115         self.ty = ty  # Type
 116         self.name = name  # String
 117         self.value = value  # list of integers or floating points
 118
 119
 120 # Class to represent an IR instruction (shuffle/select).
 121 class Instruction(Value):
 122     def __init__(self, name, ty, op0, op1, mask):
 123         Value.__init__(self, name, ty)
 124         self.op0 = op0  # Value
 125         self.op1 = op1  # Value
 126         self.mask = mask  # list of integers
 127
 128     def dump(self):
 129         pass
 130
 131     def calc_value(self):
 132         pass
 133
 134
 135 # Class to represent an IR shuffle instruction
 136 class ShufInstr(Instruction):
 137
 138     shuf_template = (
 139         "  {name} = shufflevector {ty} {op0}, {ty} {op1}, <{num} x i32> {mask}\n"
 140     )
 141
 142     def __init__(self, name, ty, op0, op1, mask):
 143         Instruction.__init__(self, "%shuf" + name, ty, op0, op1, mask)
 144
 145     def dump(self):
 146         str_mask = [
 147             ("i32 " + str(idx)) if idx != -1 else "i32 undef" for idx in self.mask
 148         ]
 149         str_mask = "<" + (", ").join(str_mask) + ">"
 150         return self.shuf_template.format(
 151             name=self.name,
 152             ty=self.ty.dump(),
 153             op0=self.op0.name,
 154             op1=self.op1.name,
 155             num=self.ty.elt_num,
 156             mask=str_mask,
 157         )
 158
 159     def calc_value(self):
 160         if self.value is not None:
 161             print("Trying to calculate the value of a shuffle instruction twice")
 162             exit(1)
 163
 164         result = []
 165         for i in range(len(self.mask)):
 166             index = self.mask[i]
 167
 168             if index < self.ty.elt_num and index >= 0:
 169                 result.append(self.op0.value[index])
 170             elif index >= self.ty.elt_num:
 171                 index = index % self.ty.elt_num
 172                 result.append(self.op1.value[index])
 173             else:  # -1 => undef
 174                 result.append(-1)
 175
 176         self.value = result
 177
 178
 179 # Class to represent an IR select instruction
 180 class SelectInstr(Instruction):
 181
 182     sel_template = "  {name} = select <{num} x i1> {mask}, {ty} {op0}, {ty} {op1}\n"
 183
 184     def __init__(self, name, ty, op0, op1, mask):
 185         Instruction.__init__(self, "%sel" + name, ty, op0, op1, mask)
 186
 187     def dump(self):
 188         str_mask = [
 189             ("i1 " + str(idx)) if idx != -1 else "i1 undef" for idx in self.mask
 190         ]
 191         str_mask = "<" + (", ").join(str_mask) + ">"
 192         return self.sel_template.format(
 193             name=self.name,
 194             ty=self.ty.dump(),
 195             op0=self.op0.name,
 196             op1=self.op1.name,
 197             num=self.ty.elt_num,
 198             mask=str_mask,
 199         )
 200
 201     def calc_value(self):
 202         if self.value is not None:
 203             print("Trying to calculate the value of a select instruction twice")
 204             exit(1)
 205
 206         result = []
 207         for i in range(len(self.mask)):
 208             index = self.mask[i]
 209
 210             if index == 1:
 211                 result.append(self.op0.value[i])
 212             elif index == 0:
 213                 result.append(self.op1.value[i])
 214             else:  # -1 => undef
 215                 result.append(-1)
 216
 217         self.value = result
 218
 219
 220 # Returns a list of Values initialized with actual numbers according to the
 221 # provided type
 222 def gen_inputs(ty, num):
 223     inputs = []
 224     for i in range(num):
 225         inp = []
 226         for j in range(ty.elt_num):
 227             if ty.is_float:
 228                 inp.append(float(i * ty.elt_num + j))
 229             else:
 230                 inp.append((i * ty.elt_num + j) % (1 << ty.elt_width))
 231         inputs.append(Value("%inp" + str(i), ty, inp))
 232
 233     return inputs
 234
 235
 236 # Returns a random vector type to be tested
 237 # In case one of the dimensions (scalar type/number of elements) is provided,
 238 # fill the blank dimension and return appropriate Type object.
 239 def get_random_type(ty, num_elts):
 240     if ty is not None:
 241         if ty == "i8":
 242             is_float = False
 243             width = 8
 244         elif ty == "i16":
 245             is_float = False
 246             width = 16
 247         elif ty == "i32":
 248             is_float = False
 249             width = 32
 250         elif ty == "i64":
 251             is_float = False
 252             width = 64
 253         elif ty == "f32":
 254             is_float = True
 255             width = 32
 256         elif ty == "f64":
 257             is_float = True
 258             width = 64
 259
 260     int_elt_widths = [8, 16, 32, 64]
 261     float_elt_widths = [32, 64]
 262
 263     if num_elts is None:
 264         num_elts = random.choice(range(2, 65))
 265
 266     if ty is None:
 267         # 1 for integer type, 0 for floating-point
 268         if random.randint(0, 1):
 269             is_float = False
 270             width = random.choice(int_elt_widths)
 271         else:
 272             is_float = True
 273             width = random.choice(float_elt_widths)
 274
 275     return Type(is_float, width, num_elts)
 276
 277
 278 # Generate mask for shufflevector IR instruction, with SHUF_UNDEF_POS possibility
 279 # of one undef index.
 280 def gen_shuf_mask(ty):
 281     mask = []
 282     for i in range(ty.elt_num):
 283         if SHUF_UNDEF_POS / ty.elt_num > random.random():
 284             mask.append(-1)
 285         else:
 286             mask.append(random.randint(0, ty.elt_num * 2 - 1))
 287
 288     return mask
 289
 290
 291 # Generate mask for select IR instruction, with SEL_UNDEF_POS possibility
 292 # of one undef index.
 293 def gen_sel_mask(ty):
 294     mask = []
 295     for i in range(ty.elt_num):
 296         if SEL_UNDEF_POS / ty.elt_num > random.random():
 297             mask.append(-1)
 298         else:
 299             mask.append(random.randint(0, 1))
 300
 301     return mask
 302
 303
 304 # Generate shuffle instructions with optional select instruction after.
 305 def gen_insts(inputs, ty):
 306     int_zero_init = Value("zeroinitializer", ty, [0] * ty.elt_num)
 307     float_zero_init = Value("zeroinitializer", ty, [0.0] * ty.elt_num)
 308
 309     insts = []
 310     name_idx = 0
 311     while len(inputs) > 1:
 312         # Choose 2 available Values - remove them from inputs list.
 313         [idx0, idx1] = sorted(random.sample(range(len(inputs)), 2))
 314         op0 = inputs[idx0]
 315         op1 = inputs[idx1]
 316
 317         # Create the shuffle instruction.
 318         shuf_mask = gen_shuf_mask(ty)
 319         shuf_inst = ShufInstr(str(name_idx), ty, op0, op1, shuf_mask)
 320         shuf_inst.calc_value()
 321
 322         # Add the new shuffle instruction to the list of instructions.
 323         insts.append(shuf_inst)
 324
 325         # Optionally, add select instruction with the result of the previous shuffle.
 326         if random.random() < ADD_SEL_POS:
 327             #  Either blending with a random Value or with an all-zero vector.
 328             if random.random() < MERGE_SEL_POS:
 329                 op2 = random.choice(inputs)
 330             else:
 331                 op2 = float_zero_init if ty.is_float else int_zero_init
 332
 333             select_mask = gen_sel_mask(ty)
 334             select_inst = SelectInstr(str(name_idx), ty, shuf_inst, op2, select_mask)
 335             select_inst.calc_value()
 336
 337             # Add the select instructions to the list of instructions and to the available Values.
 338             insts.append(select_inst)
 339             inputs.append(select_inst)
 340         else:
 341             # If the shuffle instruction is not followed by select, add it to the available Values.
 342             inputs.append(shuf_inst)
 343
 344         del inputs[idx1]
 345         del inputs[idx0]
 346         name_idx += 1
 347
 348     return insts
 349
 350
 351 def main():
 352     parser = argparse.ArgumentParser(description=__doc__)
 353     parser.add_argument(
 354         "--seed", default=str(uuid.uuid4()), help="A string used to seed the RNG"
 355     )
 356     parser.add_argument(
 357         "--max-num-inputs",
 358         type=int,
 359         default=20,
 360         help="Specify the maximum number of vector inputs for the test. (default: 20)",
 361     )
 362     parser.add_argument(
 363         "--min-num-inputs",
 364         type=int,
 365         default=10,
 366         help="Specify the minimum number of vector inputs for the test. (default: 10)",
 367     )
 368     parser.add_argument(
 369         "--type",
 370         default=None,
 371         help="""
 372                           Choose specific type to be tested.
 373                           i8, i16, i32, i64, f32 or f64.
 374                           (default: random)""",
 375     )
 376     parser.add_argument(
 377         "--num-elts",
 378         default=None,
 379         type=int,
 380         help="Choose specific number of vector elements to be tested. (default: random)",
 381     )
 382     args = parser.parse_args()
 383
 384     print("; The seed used for this test is " + args.seed)
 385
 386     assert (
 387         args.min_num_inputs < args.max_num_inputs
 388     ), "Minimum value greater than maximum."
 389     assert args.type in [None, "i8", "i16", "i32", "i64", "f32", "f64"], "Illegal type."
 390     assert (
 391         args.num_elts is None or args.num_elts > 0
 392     ), "num_elts must be a positive integer."
 393
 394     random.seed(args.seed)
 395     ty = get_random_type(args.type, args.num_elts)
 396     inputs = gen_inputs(ty, random.randint(args.min_num_inputs, args.max_num_inputs))
 397     inputs_str = (", ").join([inp.ty.dump() + " " + inp.name for inp in inputs])
 398     inputs_values = [inp.value for inp in inputs]
 399
 400     insts = gen_insts(inputs, ty)
 401
 402     assert len(inputs) == 1, "Only one value should be left after generating phase"
 403     res = inputs[0]
 404
 405     # print the actual test function by dumping the generated instructions.
 406     insts_str = "".join([inst.dump() for inst in insts])
 407     print(
 408         test_template.format(
 409             ty=ty.dump(), inputs=inputs_str, instructions=insts_str, last_name=res.name
 410         )
 411     )
 412
 413     # Print the error message templates as global strings
 414     for i in range(len(res.value)):
 415         pad = "".join(["\\00"] * (31 - len(str(i)) - len(str(res.value[i]))))
 416         print(error_template.format(lane=str(i), exp=str(res.value[i]), padding=pad))
 417
 418     # Prepare the runtime checks and failure handlers.
 419     scalar_ty = ty.get_scalar_type()
 420     check_die = ""
 421     i_f = "f" if ty.is_float else "i"
 422     ordered = "o" if ty.is_float else ""
 423     for i in range(len(res.value)):
 424         if res.value[i] != -1:
 425             # Emit runtime check for each non-undef expected value.
 426             check_die += check_template.format(
 427                 lane=str(i),
 428                 n_lane=str(i + 1),
 429                 ty=ty.dump(),
 430                 i_f=i_f,
 431                 scalar_ty=scalar_ty.dump(),
 432                 exp=str(res.value[i]),
 433                 ordered=ordered,
 434             )
 435             # Emit failure handler for each runtime check with proper error message
 436             check_die += die_template.format(lane=str(i), scalar_ty=scalar_ty.dump())
 437         else:
 438             # Ignore lanes with undef result
 439             check_die += undef_check_template.format(lane=str(i), n_lane=str(i + 1))
 440
 441     check_die += "\ntest." + str(len(res.value)) + ":\n"
 442     check_die += "  ret i32 0"
 443
 444     # Prepare the input values passed to the test function.
 445     inputs_values = [
 446         ", ".join([scalar_ty.dump() + " " + str(i) for i in inp])
 447         for inp in inputs_values
 448     ]
 449     inputs = ", ".join([ty.dump() + " <" + inp + ">" for inp in inputs_values])
 450
 451     print(main_template.format(ty=ty.dump(), inputs=inputs, check_die=check_die))
 452
 453
 454 if __name__ == "__main__":
 455     main()