utils/generate-test-checks.py - llvm-project/mlir - Git at Google

 #!/usr/bin/env python3
 """A script to generate FileCheck statements for mlir unit tests.

 This script is a utility to add FileCheck patterns to an mlir file.

 NOTE: The input .mlir is expected to be the output from the parser, not a
 stripped down variant.

 Example usage:
 $ generate-test-checks.py foo.mlir
 $ mlir-opt foo.mlir -transformation | generate-test-checks.py
 $ mlir-opt foo.mlir -transformation | generate-test-checks.py --source foo.mlir
 $ mlir-opt foo.mlir -transformation | generate-test-checks.py --source foo.mlir -i
 $ mlir-opt foo.mlir -transformation | generate-test-checks.py --source foo.mlir -i --source_delim_regex='gpu.func @'

 The script will heuristically generate CHECK/CHECK-LABEL commands for each line
 within the file. By default this script will also try to insert string
 substitution blocks for all SSA value names. If --source file is specified, the
 script will attempt to insert the generated CHECKs to the source file by looking
 for line positions matched by --source_delim_regex.

 The script is designed to make adding checks to a test case fast, it is *not*
 designed to be authoritative about what constitutes a good test!
 """

 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

 import argparse
 import os  # Used to advertise this file's name ("autogenerated_note").
 import re
 import sys

 ADVERT_BEGIN = "// NOTE: Assertions have been autogenerated by "
 ADVERT_END = """
 // The script is designed to make adding checks to
 // a test case fast, it is *not* designed to be authoritative
 // about what constitutes a good test! The CHECK should be
 // minimized and named to reflect the test intent.
 """


 # Regex command to match an SSA identifier.
 SSA_RE_STR = "[0-9]+|[a-zA-Z$._-][a-zA-Z0-9$._-]*"
 SSA_RE = re.compile(SSA_RE_STR)

 # Regex matching the left-hand side of an assignment
 SSA_RESULTS_STR = r'\s*(%' + SSA_RE_STR + r')(\s*,\s*(%' + SSA_RE_STR + r'))*\s*='
 SSA_RESULTS_RE = re.compile(SSA_RESULTS_STR)

 # Regex matching attributes
 ATTR_RE_STR = r'(#[a-zA-Z._-][a-zA-Z0-9._-]*)'
 ATTR_RE = re.compile(ATTR_RE_STR)

 # Regex matching the left-hand side of an attribute definition
 ATTR_DEF_RE_STR = r'\s*' + ATTR_RE_STR + r'\s*='
 ATTR_DEF_RE = re.compile(ATTR_DEF_RE_STR)


 # Class used to generate and manage string substitution blocks for SSA value
 # names.
 class VariableNamer:
     def __init__(self, variable_names):
         self.scopes = []
         self.name_counter = 0

         # Number of variable names to still generate in parent scope
         self.generate_in_parent_scope_left = 0

         # Parse variable names
         self.variable_names = [name.upper() for name in variable_names.split(',')]
         self.used_variable_names = set()

     # Generate the following 'n' variable names in the parent scope.
     def generate_in_parent_scope(self, n):
         self.generate_in_parent_scope_left = n

     # Generate a substitution name for the given ssa value name.
     def generate_name(self, source_variable_name):

         # Compute variable name
         variable_name = self.variable_names.pop(0) if len(self.variable_names) > 0 else ''
         if variable_name == '':
             variable_name = "VAL_" + str(self.name_counter)
             self.name_counter += 1

         # Scope where variable name is saved
         scope = len(self.scopes) - 1
         if self.generate_in_parent_scope_left > 0:
             self.generate_in_parent_scope_left -= 1
             scope = len(self.scopes) - 2
         assert(scope >= 0)

         # Save variable
         if variable_name in self.used_variable_names:
             raise RuntimeError(variable_name + ': duplicate variable name')
         self.scopes[scope][source_variable_name] = variable_name
         self.used_variable_names.add(variable_name)

         return variable_name

     # Push a new variable name scope.
     def push_name_scope(self):
         self.scopes.append({})

     # Pop the last variable name scope.
     def pop_name_scope(self):
         self.scopes.pop()

     # Return the level of nesting (number of pushed scopes).
     def num_scopes(self):
         return len(self.scopes)

     # Reset the counter and used variable names.
     def clear_names(self):
         self.name_counter = 0
         self.used_variable_names = set()

 class AttributeNamer:

     def __init__(self, attribute_names):
         self.name_counter = 0
         self.attribute_names = [name.upper() for name in attribute_names.split(',')]
         self.map = {}
         self.used_attribute_names = set()

     # Generate a substitution name for the given attribute name.
     def generate_name(self, source_attribute_name):

         # Compute FileCheck name
         attribute_name = self.attribute_names.pop(0) if len(self.attribute_names) > 0 else ''
         if attribute_name == '':
             attribute_name = "ATTR_" + str(self.name_counter)
             self.name_counter += 1

         # Prepend global symbol
         attribute_name = '$' + attribute_name

         # Save attribute
         if attribute_name in self.used_attribute_names:
             raise RuntimeError(attribute_name + ': duplicate attribute name')
         self.map[source_attribute_name] = attribute_name
         self.used_attribute_names.add(attribute_name)
         return attribute_name

     # Get the saved substitution name for the given attribute name. If no name
     # has been generated for the given attribute yet, the source attribute name
     # itself is returned.
     def get_name(self, source_attribute_name):
         return self.map[source_attribute_name] if source_attribute_name in self.map else '?'

 # Return the number of SSA results in a line of type
 #   %0, %1, ... = ...
 # The function returns 0 if there are no results.
 def get_num_ssa_results(input_line):
     m = SSA_RESULTS_RE.match(input_line)
     return m.group().count('%') if m else 0


 # Process a line of input that has been split at each SSA identifier '%'.
 def process_line(line_chunks, variable_namer):
     output_line = ""

     # Process the rest that contained an SSA value name.
     for chunk in line_chunks:
         m = SSA_RE.match(chunk)
         ssa_name = m.group(0) if m is not None else ''

         # Check if an existing variable exists for this name.
         variable = None
         for scope in variable_namer.scopes:
             variable = scope.get(ssa_name)
             if variable is not None:
                 break

         # If one exists, then output the existing name.
         if variable is not None:
             output_line += "%[[" + variable + "]]"
         else:
             # Otherwise, generate a new variable.
             variable = variable_namer.generate_name(ssa_name)
             output_line += "%[[" + variable + ":.*]]"

         # Append the non named group.
         output_line += chunk[len(ssa_name) :]

     return output_line.rstrip() + "\n"


 # Process the source file lines. The source file doesn't have to be .mlir.
 def process_source_lines(source_lines, note, args):
     source_split_re = re.compile(args.source_delim_regex)

     source_segments = [[]]
     for line in source_lines:
         # Remove previous note.
         if line == note:
             continue
         # Remove previous CHECK lines.
         if line.find(args.check_prefix) != -1:
             continue
         # Segment the file based on --source_delim_regex.
         if source_split_re.search(line):
             source_segments.append([])

         source_segments[-1].append(line + "\n")
     return source_segments

 def process_attribute_definition(line, attribute_namer, output):
     m = ATTR_DEF_RE.match(line)
     if m:
         attribute_name = attribute_namer.generate_name(m.group(1))
         line = '// CHECK: #[[' + attribute_name + ':.+]] =' + line[len(m.group(0)):] + '\n'
         output.write(line)

 def process_attribute_references(line, attribute_namer):

     output_line = ''
     components = ATTR_RE.split(line)
     for component in components:
         m = ATTR_RE.match(component)
         if m:
             output_line += '#[[' + attribute_namer.get_name(m.group(1)) + ']]'
             output_line += component[len(m.group()):]
         else:
             output_line += component
     return output_line

 # Pre-process a line of input to remove any character sequences that will be
 # problematic with FileCheck.
 def preprocess_line(line):
     # Replace any double brackets, '[[' with escaped replacements. '[['
     # corresponds to variable names in FileCheck.
     output_line = line.replace("[[", "{{\\[\\[}}")

     # Replace any single brackets that are followed by an SSA identifier, the
     # identifier will be replace by a variable; Creating the same situation as
     # above.
     output_line = output_line.replace("[%", "{{\\[}}%")

     return output_line


 def main():
     parser = argparse.ArgumentParser(
         description=__doc__, formatter_class=argparse.RawTextHelpFormatter
     )
     parser.add_argument(
         "--check-prefix", default="CHECK", help="Prefix to use from check file."
     )
     parser.add_argument(
         "-o", "--output", nargs="?", type=argparse.FileType("w"), default=None
     )
     parser.add_argument(
         "input", nargs="?", type=argparse.FileType("r"), default=sys.stdin
     )
     parser.add_argument(
         "--source",
         type=str,
         help="Print each CHECK chunk before each delimeter line in the source"
         "file, respectively. The delimeter lines are identified by "
         "--source_delim_regex.",
     )
     parser.add_argument("--source_delim_regex", type=str, default="func @")
     parser.add_argument(
         "--starts_from_scope",
         type=int,
         default=1,
         help="Omit the top specified level of content. For example, by default "
         'it omits "module {"',
     )
     parser.add_argument("-i", "--inplace", action="store_true", default=False)
     parser.add_argument(
         "--variable_names",
         type=str,
         default='',
         help="Names to be used in FileCheck regular expression to represent SSA "
         "variables in the order they are encountered. Separate names with commas, "
         "and leave empty entries for default names (e.g.: 'DIM,,SUM,RESULT')")
     parser.add_argument(
         "--attribute_names",
         type=str,
         default='',
         help="Names to be used in FileCheck regular expression to represent "
         "attributes in the order they are defined. Separate names with commas,"
         "commas, and leave empty entries for default names (e.g.: 'MAP0,,,MAP1')")

     args = parser.parse_args()

     # Open the given input file.
     input_lines = [l.rstrip() for l in args.input]
     args.input.close()

     # Generate a note used for the generated check file.
     script_name = os.path.basename(__file__)
     autogenerated_note = ADVERT_BEGIN + "utils/" + script_name + "\n" + ADVERT_END

     source_segments = None
     if args.source:
         source_segments = process_source_lines(
             [l.rstrip() for l in open(args.source, "r")], autogenerated_note, args
         )

     if args.inplace:
         assert args.output is None
         output = open(args.source, "w")
     elif args.output is None:
         output = sys.stdout
     else:
         output = args.output

     output_segments = [[]]

     # Namers
     variable_namer = VariableNamer(args.variable_names)
     attribute_namer = AttributeNamer(args.attribute_names)

     # Process lines
     for input_line in input_lines:
         if not input_line:
             continue

         # Check if this is an attribute definition and process it
         process_attribute_definition(input_line, attribute_namer, output)

         # Lines with blocks begin with a ^. These lines have a trailing comment
         # that needs to be stripped.
         lstripped_input_line = input_line.lstrip()
         is_block = lstripped_input_line[0] == "^"
         if is_block:
             input_line = input_line.rsplit("//", 1)[0].rstrip()

         cur_level = variable_namer.num_scopes()

         # If the line starts with a '}', pop the last name scope.
         if lstripped_input_line[0] == "}":
             variable_namer.pop_name_scope()
             cur_level = variable_namer.num_scopes()

         # If the line ends with a '{', push a new name scope.
         if input_line[-1] == "{":
             variable_namer.push_name_scope()
             if cur_level == args.starts_from_scope:
                 output_segments.append([])

             # Result SSA values must still be pushed to parent scope
             num_ssa_results = get_num_ssa_results(input_line)
             variable_namer.generate_in_parent_scope(num_ssa_results)

         # Omit lines at the near top level e.g. "module {".
         if cur_level < args.starts_from_scope:
             continue

         if len(output_segments[-1]) == 0:
             variable_namer.clear_names()

         # Preprocess the input to remove any sequences that may be problematic with
         # FileCheck.
         input_line = preprocess_line(input_line)

         # Process uses of attributes in this line
         input_line = process_attribute_references(input_line, attribute_namer)

         # Split the line at the each SSA value name.
         ssa_split = input_line.split("%")

         # If this is a top-level operation use 'CHECK-LABEL', otherwise 'CHECK:'.
         if len(output_segments[-1]) != 0 or not ssa_split[0]:
             output_line = "// " + args.check_prefix + ": "
             # Pad to align with the 'LABEL' statements.
             output_line += " " * len("-LABEL")

             # Output the first line chunk that does not contain an SSA name.
             output_line += ssa_split[0]

             # Process the rest of the input line.
             output_line += process_line(ssa_split[1:], variable_namer)

         else:
             # Output the first line chunk that does not contain an SSA name for the
             # label.
             output_line = "// " + args.check_prefix + "-LABEL: " + ssa_split[0] + "\n"

             # Process the rest of the input line on separate check lines.
             for argument in ssa_split[1:]:
                 output_line += "// " + args.check_prefix + "-SAME:  "

                 # Pad to align with the original position in the line.
                 output_line += " " * len(ssa_split[0])

                 # Process the rest of the line.
                 output_line += process_line([argument], variable_namer)

         # Append the output line.
         output_segments[-1].append(output_line)

     output.write(autogenerated_note + "\n")

     # Write the output.
     if source_segments:
         assert len(output_segments) == len(source_segments)
         for check_segment, source_segment in zip(output_segments, source_segments):
             for line in check_segment:
                 output.write(line)
             for line in source_segment:
                 output.write(line)
     else:
         for segment in output_segments:
             output.write("\n")
             for output_line in segment:
                 output.write(output_line)
         output.write("\n")
     output.close()


 if __name__ == "__main__":
     main()
	#!/usr/bin/env python3
	"""A script to generate FileCheck statements for mlir unit tests.

	This script is a utility to add FileCheck patterns to an mlir file.

	NOTE: The input .mlir is expected to be the output from the parser, not a
	stripped down variant.

	Example usage:
	$ generate-test-checks.py foo.mlir
	$ mlir-opt foo.mlir -transformation \| generate-test-checks.py
	$ mlir-opt foo.mlir -transformation \| generate-test-checks.py --source foo.mlir
	$ mlir-opt foo.mlir -transformation \| generate-test-checks.py --source foo.mlir -i
	$ mlir-opt foo.mlir -transformation \| generate-test-checks.py --source foo.mlir -i --source_delim_regex='gpu.func @'

	The script will heuristically generate CHECK/CHECK-LABEL commands for each line
	within the file. By default this script will also try to insert string
	substitution blocks for all SSA value names. If --source file is specified, the
	script will attempt to insert the generated CHECKs to the source file by looking
	for line positions matched by --source_delim_regex.

	The script is designed to make adding checks to a test case fast, it is not
	designed to be authoritative about what constitutes a good test!
	"""

	# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	# See https://llvm.org/LICENSE.txt for license information.
	# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

	import argparse
	import os # Used to advertise this file's name ("autogenerated_note").
	import re
	import sys

	ADVERT_BEGIN = "// NOTE: Assertions have been autogenerated by "
	ADVERT_END = """
	// The script is designed to make adding checks to
	// a test case fast, it is not designed to be authoritative
	// about what constitutes a good test! The CHECK should be
	// minimized and named to reflect the test intent.
	"""


	# Regex command to match an SSA identifier.
	SSA_RE_STR = "[0-9]+\|[a-zA-Z$._-][a-zA-Z0-9$._-]*"
	SSA_RE = re.compile(SSA_RE_STR)

	# Regex matching the left-hand side of an assignment
	SSA_RESULTS_STR = r'\s(%' + SSA_RE_STR + r')(\s,\s(%' + SSA_RE_STR + r'))\s*='
	SSA_RESULTS_RE = re.compile(SSA_RESULTS_STR)

	# Regex matching attributes
	ATTR_RE_STR = r'(#[a-zA-Z._-][a-zA-Z0-9._-]*)'
	ATTR_RE = re.compile(ATTR_RE_STR)

	# Regex matching the left-hand side of an attribute definition
	ATTR_DEF_RE_STR = r'\s' + ATTR_RE_STR + r'\s='
	ATTR_DEF_RE = re.compile(ATTR_DEF_RE_STR)


	# Class used to generate and manage string substitution blocks for SSA value
	# names.
	class VariableNamer:
	def __init__(self, variable_names):
	self.scopes = []
	self.name_counter = 0

	# Number of variable names to still generate in parent scope
	self.generate_in_parent_scope_left = 0

	# Parse variable names
	self.variable_names = [name.upper() for name in variable_names.split(',')]
	self.used_variable_names = set()

	# Generate the following 'n' variable names in the parent scope.
	def generate_in_parent_scope(self, n):
	self.generate_in_parent_scope_left = n

	# Generate a substitution name for the given ssa value name.
	def generate_name(self, source_variable_name):

	# Compute variable name
	variable_name = self.variable_names.pop(0) if len(self.variable_names) > 0 else ''
	if variable_name == '':
	variable_name = "VAL_" + str(self.name_counter)
	self.name_counter += 1

	# Scope where variable name is saved
	scope = len(self.scopes) - 1
	if self.generate_in_parent_scope_left > 0:
	self.generate_in_parent_scope_left -= 1
	scope = len(self.scopes) - 2
	assert(scope >= 0)

	# Save variable
	if variable_name in self.used_variable_names:
	raise RuntimeError(variable_name + ': duplicate variable name')
	self.scopes[scope][source_variable_name] = variable_name
	self.used_variable_names.add(variable_name)

	return variable_name

	# Push a new variable name scope.
	def push_name_scope(self):
	self.scopes.append({})

	# Pop the last variable name scope.
	def pop_name_scope(self):
	self.scopes.pop()

	# Return the level of nesting (number of pushed scopes).
	def num_scopes(self):
	return len(self.scopes)

	# Reset the counter and used variable names.
	def clear_names(self):
	self.name_counter = 0
	self.used_variable_names = set()

	class AttributeNamer:

	def __init__(self, attribute_names):
	self.name_counter = 0
	self.attribute_names = [name.upper() for name in attribute_names.split(',')]
	self.map = {}
	self.used_attribute_names = set()

	# Generate a substitution name for the given attribute name.
	def generate_name(self, source_attribute_name):

	# Compute FileCheck name
	attribute_name = self.attribute_names.pop(0) if len(self.attribute_names) > 0 else ''
	if attribute_name == '':
	attribute_name = "ATTR_" + str(self.name_counter)
	self.name_counter += 1

	# Prepend global symbol
	attribute_name = '$' + attribute_name

	# Save attribute
	if attribute_name in self.used_attribute_names:
	raise RuntimeError(attribute_name + ': duplicate attribute name')
	self.map[source_attribute_name] = attribute_name
	self.used_attribute_names.add(attribute_name)
	return attribute_name

	# Get the saved substitution name for the given attribute name. If no name
	# has been generated for the given attribute yet, the source attribute name
	# itself is returned.
	def get_name(self, source_attribute_name):
	return self.map[source_attribute_name] if source_attribute_name in self.map else '?'

	# Return the number of SSA results in a line of type
	# %0, %1, ... = ...
	# The function returns 0 if there are no results.
	def get_num_ssa_results(input_line):
	m = SSA_RESULTS_RE.match(input_line)
	return m.group().count('%') if m else 0


	# Process a line of input that has been split at each SSA identifier '%'.
	def process_line(line_chunks, variable_namer):
	output_line = ""

	# Process the rest that contained an SSA value name.
	for chunk in line_chunks:
	m = SSA_RE.match(chunk)
	ssa_name = m.group(0) if m is not None else ''

	# Check if an existing variable exists for this name.
	variable = None
	for scope in variable_namer.scopes:
	variable = scope.get(ssa_name)
	if variable is not None:
	break

	# If one exists, then output the existing name.
	if variable is not None:
	output_line += "%[[" + variable + "]]"
	else:
	# Otherwise, generate a new variable.
	variable = variable_namer.generate_name(ssa_name)
	output_line += "%[[" + variable + ":.*]]"

	# Append the non named group.
	output_line += chunk[len(ssa_name) :]

	return output_line.rstrip() + "\n"


	# Process the source file lines. The source file doesn't have to be .mlir.
	def process_source_lines(source_lines, note, args):
	source_split_re = re.compile(args.source_delim_regex)

	source_segments = [[]]
	for line in source_lines:
	# Remove previous note.
	if line == note:
	continue
	# Remove previous CHECK lines.
	if line.find(args.check_prefix) != -1:
	continue
	# Segment the file based on --source_delim_regex.
	if source_split_re.search(line):
	source_segments.append([])

	source_segments[-1].append(line + "\n")
	return source_segments

	def process_attribute_definition(line, attribute_namer, output):
	m = ATTR_DEF_RE.match(line)
	if m:
	attribute_name = attribute_namer.generate_name(m.group(1))
	line = '// CHECK: #[[' + attribute_name + ':.+]] =' + line[len(m.group(0)):] + '\n'
	output.write(line)

	def process_attribute_references(line, attribute_namer):

	output_line = ''
	components = ATTR_RE.split(line)
	for component in components:
	m = ATTR_RE.match(component)
	if m:
	output_line += '#[[' + attribute_namer.get_name(m.group(1)) + ']]'
	output_line += component[len(m.group()):]
	else:
	output_line += component
	return output_line

	# Pre-process a line of input to remove any character sequences that will be
	# problematic with FileCheck.
	def preprocess_line(line):
	# Replace any double brackets, '[[' with escaped replacements. '[['
	# corresponds to variable names in FileCheck.
	output_line = line.replace("[[", "{{\\[\\[}}")

	# Replace any single brackets that are followed by an SSA identifier, the
	# identifier will be replace by a variable; Creating the same situation as
	# above.
	output_line = output_line.replace("[%", "{{\\[}}%")

	return output_line


	def main():
	parser = argparse.ArgumentParser(
	description=__doc__, formatter_class=argparse.RawTextHelpFormatter
	)
	parser.add_argument(
	"--check-prefix", default="CHECK", help="Prefix to use from check file."
	)
	parser.add_argument(
	"-o", "--output", nargs="?", type=argparse.FileType("w"), default=None
	)
	parser.add_argument(
	"input", nargs="?", type=argparse.FileType("r"), default=sys.stdin
	)
	parser.add_argument(
	"--source",
	type=str,
	help="Print each CHECK chunk before each delimeter line in the source"
	"file, respectively. The delimeter lines are identified by "
	"--source_delim_regex.",
	)
	parser.add_argument("--source_delim_regex", type=str, default="func @")
	parser.add_argument(
	"--starts_from_scope",
	type=int,
	default=1,
	help="Omit the top specified level of content. For example, by default "
	'it omits "module {"',
	)
	parser.add_argument("-i", "--inplace", action="store_true", default=False)
	parser.add_argument(
	"--variable_names",
	type=str,
	default='',
	help="Names to be used in FileCheck regular expression to represent SSA "
	"variables in the order they are encountered. Separate names with commas, "
	"and leave empty entries for default names (e.g.: 'DIM,,SUM,RESULT')")
	parser.add_argument(
	"--attribute_names",
	type=str,
	default='',
	help="Names to be used in FileCheck regular expression to represent "
	"attributes in the order they are defined. Separate names with commas,"
	"commas, and leave empty entries for default names (e.g.: 'MAP0,,,MAP1')")

	args = parser.parse_args()

	# Open the given input file.
	input_lines = [l.rstrip() for l in args.input]
	args.input.close()

	# Generate a note used for the generated check file.
	script_name = os.path.basename(__file__)
	autogenerated_note = ADVERT_BEGIN + "utils/" + script_name + "\n" + ADVERT_END

	source_segments = None
	if args.source:
	source_segments = process_source_lines(
	[l.rstrip() for l in open(args.source, "r")], autogenerated_note, args
	)

	if args.inplace:
	assert args.output is None
	output = open(args.source, "w")
	elif args.output is None:
	output = sys.stdout
	else:
	output = args.output

	output_segments = [[]]

	# Namers
	variable_namer = VariableNamer(args.variable_names)
	attribute_namer = AttributeNamer(args.attribute_names)

	# Process lines
	for input_line in input_lines:
	if not input_line:
	continue

	# Check if this is an attribute definition and process it
	process_attribute_definition(input_line, attribute_namer, output)

	# Lines with blocks begin with a ^. These lines have a trailing comment
	# that needs to be stripped.
	lstripped_input_line = input_line.lstrip()
	is_block = lstripped_input_line[0] == "^"
	if is_block:
	input_line = input_line.rsplit("//", 1)[0].rstrip()

	cur_level = variable_namer.num_scopes()

	# If the line starts with a '}', pop the last name scope.
	if lstripped_input_line[0] == "}":
	variable_namer.pop_name_scope()
	cur_level = variable_namer.num_scopes()

	# If the line ends with a '{', push a new name scope.
	if input_line[-1] == "{":
	variable_namer.push_name_scope()
	if cur_level == args.starts_from_scope:
	output_segments.append([])

	# Result SSA values must still be pushed to parent scope
	num_ssa_results = get_num_ssa_results(input_line)
	variable_namer.generate_in_parent_scope(num_ssa_results)

	# Omit lines at the near top level e.g. "module {".
	if cur_level < args.starts_from_scope:
	continue

	if len(output_segments[-1]) == 0:
	variable_namer.clear_names()

	# Preprocess the input to remove any sequences that may be problematic with
	# FileCheck.
	input_line = preprocess_line(input_line)

	# Process uses of attributes in this line
	input_line = process_attribute_references(input_line, attribute_namer)

	# Split the line at the each SSA value name.
	ssa_split = input_line.split("%")

	# If this is a top-level operation use 'CHECK-LABEL', otherwise 'CHECK:'.
	if len(output_segments[-1]) != 0 or not ssa_split[0]:
	output_line = "// " + args.check_prefix + ": "
	# Pad to align with the 'LABEL' statements.
	output_line += " " * len("-LABEL")

	# Output the first line chunk that does not contain an SSA name.
	output_line += ssa_split[0]

	# Process the rest of the input line.
	output_line += process_line(ssa_split[1:], variable_namer)

	else:
	# Output the first line chunk that does not contain an SSA name for the
	# label.
	output_line = "// " + args.check_prefix + "-LABEL: " + ssa_split[0] + "\n"

	# Process the rest of the input line on separate check lines.
	for argument in ssa_split[1:]:
	output_line += "// " + args.check_prefix + "-SAME: "

	# Pad to align with the original position in the line.
	output_line += " " * len(ssa_split[0])

	# Process the rest of the line.
	output_line += process_line([argument], variable_namer)

	# Append the output line.
	output_segments[-1].append(output_line)

	output.write(autogenerated_note + "\n")

	# Write the output.
	if source_segments:
	assert len(output_segments) == len(source_segments)
	for check_segment, source_segment in zip(output_segments, source_segments):
	for line in check_segment:
	output.write(line)
	for line in source_segment:
	output.write(line)
	else:
	for segment in output_segments:
	output.write("\n")
	for output_line in segment:
	output.write(output_line)
	output.write("\n")
	output.close()


	if __name__ == "__main__":
	main()