#!/usr/bin/env python3

"""A script to generate FileCheck statements for 'opt' regression tests.

This script is a utility to update LLVM opt test cases with new
FileCheck patterns. It can either update all of the tests in the file or
a single test function.

Example usage:

# Default to using `opt` as found in your PATH.
$ update_test_checks.py test/foo.ll

# Override the path lookup.
$ update_test_checks.py --tool-binary=../bin/opt test/foo.ll

# Use a custom tool instead of `opt`.
$ update_test_checks.py --tool=yourtool test/foo.ll

Workflow:
1. Make a compiler patch that requires updating some number of FileCheck lines
   in regression test files.
2. Save the patch and revert it from your local work area.
3. Update the RUN-lines in the affected regression tests to look canonical.
   Example: "; RUN: opt < %s -instcombine -S | FileCheck %s"
4. Refresh the FileCheck lines for either the entire file or select functions by
   running this script.
5. Commit the fresh baseline of checks.
6. Apply your patch from step 1 and rebuild your local binaries.
7. Re-run this script on affected regression tests.
8. Check the diffs to ensure the script has done something reasonable.
9. Submit a patch including the regression test diffs for review.
"""

from __future__ import print_function

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

from UpdateTestChecks import common


def update_test(ti: common.TestInfo):
    # If requested we scrub trailing attribute annotations, e.g., '#0', together with whitespaces
    if ti.args.scrub_attributes:
        common.SCRUB_TRAILING_WHITESPACE_TEST_RE = (
            common.SCRUB_TRAILING_WHITESPACE_AND_ATTRIBUTES_RE
        )
    else:
        common.SCRUB_TRAILING_WHITESPACE_TEST_RE = common.SCRUB_TRAILING_WHITESPACE_RE

    tool_basename = ti.args.tool

    prefix_list = []
    for l in ti.run_lines:
        if "|" not in l:
            common.warn("Skipping unparsable RUN line: " + l)
            continue

        cropped_content = l
        if "%if" in l:
            match = re.search(r"%{\s*(.*?)\s*%}", l)
            if match:
                cropped_content = match.group(1)

        commands = [cmd.strip() for cmd in cropped_content.split("|")]
        assert len(commands) >= 2
        preprocess_cmd = None
        if len(commands) > 2:
            preprocess_cmd = " | ".join(commands[:-2])
        tool_cmd = commands[-2]
        filecheck_cmd = commands[-1]
        common.verify_filecheck_prefixes(filecheck_cmd)
        if not tool_cmd.startswith(tool_basename + " "):
            common.warn("Skipping non-%s RUN line: %s" % (tool_basename, l))
            continue

        if not filecheck_cmd.startswith("FileCheck "):
            common.warn("Skipping non-FileChecked RUN line: " + l)
            continue

        tool_cmd_args = tool_cmd[len(tool_basename) :].strip()
        tool_cmd_args = tool_cmd_args.replace("< %s", "").replace("%s", "").strip()
        check_prefixes = common.get_check_prefixes(filecheck_cmd)

        # FIXME: We should use multiple check prefixes to common check lines. For
        # now, we just ignore all but the last.
        prefix_list.append((check_prefixes, tool_cmd_args, preprocess_cmd))

    ginfo = common.make_ir_generalizer(ti.args.version, ti.args.check_globals == "none")
    global_vars_seen_dict = {}
    builder = common.FunctionTestBuilder(
        run_list=prefix_list,
        flags=ti.args,
        scrubber_args=[],
        path=ti.path,
        ginfo=ginfo,
    )

    tool_binary = ti.args.tool_binary
    if not tool_binary:
        tool_binary = tool_basename

    for prefixes, tool_args, preprocess_cmd in prefix_list:
        common.debug("Extracted tool cmd: " + tool_basename + " " + tool_args)
        common.debug("Extracted FileCheck prefixes: " + str(prefixes))

        raw_tool_output = common.invoke_tool(
            tool_binary,
            tool_args,
            ti.path,
            preprocess_cmd=preprocess_cmd,
            verbose=ti.args.verbose,
        )
        builder.process_run_line(
            common.OPT_FUNCTION_RE,
            common.scrub_body,
            raw_tool_output,
            prefixes,
        )
        builder.processed_prefixes(prefixes)

    prefix_set = set([prefix for prefixes, _, _ in prefix_list for prefix in prefixes])

    if not ti.args.reset_variable_names:
        original_check_lines = common.collect_original_check_lines(ti, prefix_set)
    else:
        original_check_lines = {}

    func_dict = builder.finish_and_get_func_dict()
    is_in_function = False
    is_in_function_start = False
    has_checked_pre_function_globals = False
    common.debug("Rewriting FileCheck prefixes:", str(prefix_set))
    output_lines = []

    include_generated_funcs = common.find_arg_in_test(
        ti,
        lambda args: ti.args.include_generated_funcs,
        "--include-generated-funcs",
        True,
    )
    generated_prefixes = []
    if include_generated_funcs:
        # Generate the appropriate checks for each function.  We need to emit
        # these in the order according to the generated output so that CHECK-LABEL
        # works properly.  func_order provides that.

        # We can't predict where various passes might insert functions so we can't
        # be sure the input function order is maintained.  Therefore, first spit
        # out all the source lines.
        common.dump_input_lines(output_lines, ti, prefix_set, ";")

        args = ti.args
        if args.check_globals != "none":
            generated_prefixes.extend(
                common.add_global_checks(
                    builder.global_var_dict(),
                    ";",
                    prefix_list,
                    output_lines,
                    ginfo,
                    global_vars_seen_dict,
                    args.preserve_names,
                    True,
                    args.check_globals,
                )
            )

        # Now generate all the checks.
        generated_prefixes.extend(
            common.add_checks_at_end(
                output_lines,
                prefix_list,
                builder.func_order(),
                ";",
                lambda my_output_lines, prefixes, func: common.add_ir_checks(
                    my_output_lines,
                    ";",
                    prefixes,
                    func_dict,
                    func,
                    False,
                    args.function_signature,
                    ginfo,
                    global_vars_seen_dict,
                    is_filtered=builder.is_filtered(),
                    original_check_lines=original_check_lines.get(func, {}),
                ),
            )
        )
    else:
        # "Normal" mode.
        dropped_previous_line = False
        for input_line_info in ti.iterlines(output_lines):
            input_line = input_line_info.line
            args = input_line_info.args
            if is_in_function_start:
                if input_line == "":
                    continue
                if input_line.lstrip().startswith(";"):
                    m = common.CHECK_RE.match(input_line)
                    if not m or m.group(1) not in prefix_set:
                        output_lines.append(input_line)
                        continue

                # Print out the various check lines here.
                generated_prefixes.extend(
                    common.add_ir_checks(
                        output_lines,
                        ";",
                        prefix_list,
                        func_dict,
                        func_name,
                        args.preserve_names,
                        args.function_signature,
                        ginfo,
                        global_vars_seen_dict,
                        is_filtered=builder.is_filtered(),
                        original_check_lines=original_check_lines.get(func_name, {}),
                    )
                )
                is_in_function_start = False

            m = common.IR_FUNCTION_RE.match(input_line)
            if m and not has_checked_pre_function_globals:
                if args.check_globals:
                    generated_prefixes.extend(
                        common.add_global_checks(
                            builder.global_var_dict(),
                            ";",
                            prefix_list,
                            output_lines,
                            ginfo,
                            global_vars_seen_dict,
                            args.preserve_names,
                            True,
                            args.check_globals,
                        )
                    )
                has_checked_pre_function_globals = True

            if common.should_add_line_to_output(
                input_line,
                prefix_set,
                skip_global_checks=not is_in_function,
                skip_same_checks=dropped_previous_line,
            ):
                # This input line of the function body will go as-is into the output.
                # Except make leading whitespace uniform: 2 spaces. 4 for debug records.
                indent = (
                    "  " if not common.IS_DEBUG_RECORD_RE.match(input_line) else "    "
                )
                input_line = common.SCRUB_LEADING_WHITESPACE_RE.sub(indent, input_line)
                output_lines.append(input_line)
                dropped_previous_line = False
                if input_line.strip() == "}":
                    is_in_function = False
                    continue
            else:
                # If we are removing a check line, and the next line is CHECK-SAME, it MUST also be removed
                dropped_previous_line = True

            if is_in_function:
                continue

            m = common.IR_FUNCTION_RE.match(input_line)
            if not m:
                continue
            func_name = m.group(1)
            if args.function is not None and func_name != args.function:
                # When filtering on a specific function, skip all others.
                continue
            is_in_function = is_in_function_start = True

    if args.check_globals != "none":
        generated_prefixes.extend(
            common.add_global_checks(
                builder.global_var_dict(),
                ";",
                prefix_list,
                output_lines,
                ginfo,
                global_vars_seen_dict,
                args.preserve_names,
                False,
                args.check_globals,
            )
        )
    if ti.args.gen_unused_prefix_body:
        output_lines.extend(
            ti.get_checks_for_unused_prefixes(prefix_list, generated_prefixes)
        )
    common.debug("Writing %d lines to %s..." % (len(output_lines), ti.path))

    with open(ti.path, "wb") as f:
        f.writelines(["{}\n".format(l).encode("utf-8") for l in output_lines])


def main():
    from argparse import RawTextHelpFormatter

    parser = argparse.ArgumentParser(
        description=__doc__, formatter_class=RawTextHelpFormatter
    )
    parser.add_argument(
        "--tool",
        default="opt",
        help='The name of the tool used to generate the test case (defaults to "opt")',
    )
    parser.add_argument(
        "--tool-binary",
        "--opt-binary",
        help="The tool binary used to generate the test case",
    )
    parser.add_argument("--function", help="The function in the test file to update")
    parser.add_argument(
        "-p", "--preserve-names", action="store_true", help="Do not scrub IR names"
    )
    parser.add_argument(
        "--function-signature",
        action="store_true",
        help="Keep function signature information around for the check line",
    )
    parser.add_argument(
        "--scrub-attributes",
        action="store_true",
        help="Remove attribute annotations (#0) from the end of check line",
    )
    parser.add_argument(
        "--check-attributes",
        action="store_true",
        help='Check "Function Attributes" for functions',
    )
    parser.add_argument(
        "--check-globals",
        nargs="?",
        const="all",
        default="default",
        choices=["none", "smart", "all"],
        help="Check global entries (global variables, metadata, attribute sets, ...) for functions",
    )
    parser.add_argument(
        "--reset-variable-names",
        action="store_true",
        help="Reset all variable names to correspond closely to the variable names in IR. "
        "This tends to result in larger diffs.",
    )
    parser.add_argument("tests", nargs="+")
    initial_args = common.parse_commandline_args(parser)

    script_name = os.path.basename(__file__)

    if initial_args.tool_binary:
        tool_basename = os.path.basename(initial_args.tool_binary)
        if not re.match(r"^%s(-\d+)?(\.exe)?$" % (initial_args.tool), tool_basename):
            common.error("Unexpected tool name: " + tool_basename)
            sys.exit(1)

    returncode = 0
    for ti in common.itertests(
        initial_args.tests, parser, script_name="utils/" + script_name
    ):
        try:
            update_test(ti)
        except Exception as e:
            stderr.write(f"Error: Failed to update test {ti.path}\n")
            print_exc()
            returncode = 1
    return returncode


if __name__ == "__main__":
    sys.exit(main())