[utils][UpdateTestChecks] Extract MIR functionality into separate mir.py module (#165535)

This commit extracts some MIR-related code from `common.py` and
`update_mir_test_checks.py` into a dedicated `mir.py` module to improve
code organization. This is a preparation step for
#164965 and also moves some
pieces already moved by #140296

All code intentionally moved verbatim with minimal necessary
adaptations:
* `log()` calls converted to `print(..., file=sys.stderr)` at `mir.py`
lines 62, 64 due to a `log` locality.

Author: vpykhtin

llvm/utils/UpdateTestChecks/common.py

@@ -2396,244 +2396,6 @@ def add_analyze_checks(
     )
 
 
-IR_FUNC_NAME_RE = re.compile(
-    r"^\s*define\s+(?:internal\s+)?[^@]*@(?P<func>[A-Za-z0-9_.]+)\s*\("
-)
-IR_PREFIX_DATA_RE = re.compile(r"^ *(;|$)")
-MIR_FUNC_NAME_RE = re.compile(r" *name: *(?P<func>[A-Za-z0-9_.-]+)")
-MIR_BODY_BEGIN_RE = re.compile(r" *body: *\|")
-MIR_BASIC_BLOCK_RE = re.compile(r" *bb\.[0-9]+.*:$")
-MIR_PREFIX_DATA_RE = re.compile(r"^ *(;|bb.[0-9].*: *$|[a-z]+:( |$)|$)")
-
-
-def find_mir_functions_with_one_bb(lines, verbose=False):
-    result = []
-    cur_func = None
-    bbs = 0
-    for line in lines:
-        m = MIR_FUNC_NAME_RE.match(line)
-        if m:
-            if bbs == 1:
-                result.append(cur_func)
-            cur_func = m.group("func")
-            bbs = 0
-        m = MIR_BASIC_BLOCK_RE.match(line)
-        if m:
-            bbs += 1
-    if bbs == 1:
-        result.append(cur_func)
-    return result
-
-
-def add_mir_checks_for_function(
-    test,
-    output_lines,
-    run_list,
-    func_dict,
-    func_name,
-    single_bb,
-    print_fixed_stack,
-    first_check_is_next,
-    at_the_function_name,
-):
-    printed_prefixes = set()
-    for run in run_list:
-        for prefix in run[0]:
-            if prefix in printed_prefixes:
-                break
-            if not func_dict[prefix][func_name]:
-                continue
-            if printed_prefixes:
-                # Add some space between different check prefixes.
-                indent = len(output_lines[-1]) - len(output_lines[-1].lstrip(" "))
-                output_lines.append(" " * indent + ";")
-            printed_prefixes.add(prefix)
-            add_mir_check_lines(
-                test,
-                output_lines,
-                prefix,
-                ("@" if at_the_function_name else "") + func_name,
-                single_bb,
-                func_dict[prefix][func_name],
-                print_fixed_stack,
-                first_check_is_next,
-            )
-            break
-        else:
-            warn(
-                "Found conflicting asm for function: {}".format(func_name),
-                test_file=test,
-            )
-    return output_lines
-
-
-def add_mir_check_lines(
-    test,
-    output_lines,
-    prefix,
-    func_name,
-    single_bb,
-    func_info,
-    print_fixed_stack,
-    first_check_is_next,
-):
-    func_body = str(func_info).splitlines()
-    if single_bb:
-        # Don't bother checking the basic block label for a single BB
-        func_body.pop(0)
-
-    if not func_body:
-        warn(
-            "Function has no instructions to check: {}".format(func_name),
-            test_file=test,
-        )
-        return
-
-    first_line = func_body[0]
-    indent = len(first_line) - len(first_line.lstrip(" "))
-    # A check comment, indented the appropriate amount
-    check = "{:>{}}; {}".format("", indent, prefix)
-
-    output_lines.append("{}-LABEL: name: {}".format(check, func_name))
-
-    if print_fixed_stack:
-        output_lines.append("{}: fixedStack:".format(check))
-        for stack_line in func_info.extrascrub.splitlines():
-            filecheck_directive = check + "-NEXT"
-            output_lines.append("{}: {}".format(filecheck_directive, stack_line))
-
-    first_check = not first_check_is_next
-    for func_line in func_body:
-        if not func_line.strip():
-            # The mir printer prints leading whitespace so we can't use CHECK-EMPTY:
-            output_lines.append(check + "-NEXT: {{" + func_line + "$}}")
-            continue
-        filecheck_directive = check if first_check else check + "-NEXT"
-        first_check = False
-        check_line = "{}: {}".format(filecheck_directive, func_line[indent:]).rstrip()
-        output_lines.append(check_line)
-
-
-def should_add_mir_line_to_output(input_line, prefix_set):
-    # Skip any check lines that we're handling as well as comments
-    m = CHECK_RE.match(input_line)
-    if (m and m.group(1) in prefix_set) or input_line.strip() == ";":
-        return False
-    return True
-
-
-def add_mir_checks(
-    input_lines,
-    prefix_set,
-    autogenerated_note,
-    test,
-    run_list,
-    func_dict,
-    print_fixed_stack,
-    first_check_is_next,
-    at_the_function_name,
-):
-    simple_functions = find_mir_functions_with_one_bb(input_lines)
-
-    output_lines = []
-    output_lines.append(autogenerated_note)
-
-    func_name = None
-    state = "toplevel"
-    for input_line in input_lines:
-        if input_line == autogenerated_note:
-            continue
-
-        if state == "toplevel":
-            m = IR_FUNC_NAME_RE.match(input_line)
-            if m:
-                state = "ir function prefix"
-                func_name = m.group("func")
-            if input_line.rstrip("| \r\n") == "---":
-                state = "document"
-            output_lines.append(input_line)
-        elif state == "document":
-            m = MIR_FUNC_NAME_RE.match(input_line)
-            if m:
-                state = "mir function metadata"
-                func_name = m.group("func")
-            if input_line.strip() == "...":
-                state = "toplevel"
-                func_name = None
-            if should_add_mir_line_to_output(input_line, prefix_set):
-                output_lines.append(input_line)
-        elif state == "mir function metadata":
-            if should_add_mir_line_to_output(input_line, prefix_set):
-                output_lines.append(input_line)
-            m = MIR_BODY_BEGIN_RE.match(input_line)
-            if m:
-                if func_name in simple_functions:
-                    # If there's only one block, put the checks inside it
-                    state = "mir function prefix"
-                    continue
-                state = "mir function body"
-                add_mir_checks_for_function(
-                    test,
-                    output_lines,
-                    run_list,
-                    func_dict,
-                    func_name,
-                    single_bb=False,
-                    print_fixed_stack=print_fixed_stack,
-                    first_check_is_next=first_check_is_next,
-                    at_the_function_name=at_the_function_name,
-                )
-        elif state == "mir function prefix":
-            m = MIR_PREFIX_DATA_RE.match(input_line)
-            if not m:
-                state = "mir function body"
-                add_mir_checks_for_function(
-                    test,
-                    output_lines,
-                    run_list,
-                    func_dict,
-                    func_name,
-                    single_bb=True,
-                    print_fixed_stack=print_fixed_stack,
-                    first_check_is_next=first_check_is_next,
-                    at_the_function_name=at_the_function_name,
-                )
-
-            if should_add_mir_line_to_output(input_line, prefix_set):
-                output_lines.append(input_line)
-        elif state == "mir function body":
-            if input_line.strip() == "...":
-                state = "toplevel"
-                func_name = None
-            if should_add_mir_line_to_output(input_line, prefix_set):
-                output_lines.append(input_line)
-        elif state == "ir function prefix":
-            m = IR_PREFIX_DATA_RE.match(input_line)
-            if not m:
-                state = "ir function body"
-                add_mir_checks_for_function(
-                    test,
-                    output_lines,
-                    run_list,
-                    func_dict,
-                    func_name,
-                    single_bb=False,
-                    print_fixed_stack=print_fixed_stack,
-                    first_check_is_next=first_check_is_next,
-                    at_the_function_name=at_the_function_name,
-                )
-
-            if should_add_mir_line_to_output(input_line, prefix_set):
-                output_lines.append(input_line)
-        elif state == "ir function body":
-            if input_line.strip() == "}":
-                state = "toplevel"
-                func_name = None
-            if should_add_mir_line_to_output(input_line, prefix_set):
-                output_lines.append(input_line)
-    return output_lines
-
-
 def build_global_values_dictionary(glob_val_dict, raw_tool_output, prefixes, ginfo):
     for nameless_value in ginfo.get_nameless_values():
         if nameless_value.global_ir_rhs_regexp is None: