[Git][ghc/ghc][master] testsuite: avoid re.sub in favor of simple string replacements

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: ca79475f by Cheng Shao at 2026-01-21T16:09:00-05:00 testsuite: avoid re.sub in favor of simple string replacements This patch refactors the testsuite driver and avoids the usage of re.sub in favor of simple string replacements when possible. The changes are not comprehensive, and there are still a lot of re.sub usages lingering around the tree, but this already addresses a major performance bottleneck in the testsuite driver that might has to do with quadratic or worse slowdown in cpython's regular expression engine when handling certain regex patterns with large strings. Especially on i386, and i386 jobs are the bottlenecks of all full-ci validate pipelines! Here are the elapsed times of testing x86_64/i386 with -j48 before this patch: x86_64: `Build completed in 6m06s` i386: `Build completed in 1h36m` And with this patch: x86_64: `Build completed in 4m55s` i386: `Build completed in 4m23s` Fixes #26786. Co-authored-by: Codex - - - - - 3 changed files: - testsuite/driver/runtests.py - testsuite/driver/testlib.py - testsuite/driver/testutil.py Changes: ===================================== testsuite/driver/runtests.py ===================================== @@ -28,7 +28,7 @@ import subprocess import asyncio -from testutil import getStdout, str_warn, str_info, print_table, shorten_metric_name +from testutil import getStdout, str_warn, str_info, print_table, shorten_metric_name, str_removeprefix from testglobals import getConfig, ghc_env, TestConfig, t, \ TestOptions, brokens, PerfMetric from my_typing import TestName @@ -291,7 +291,7 @@ if windows: for line in pkginfo.split('\n'): if line.startswith('library-dirs:'): path = line.rstrip() - path = re.sub('^library-dirs: ', '', path) + path = str_removeprefix(path, 'library-dirs: ') # Use string.replace instead of re.sub, because re.sub # interprets backslashes in the replacement string as # escape sequences. ===================================== testsuite/driver/testlib.py ===================================== @@ -25,7 +25,7 @@ from testglobals import config, ghc_env, default_testopts, brokens, t, \ from testutil import strip_quotes, lndir, link_or_copy_file, passed, \ failBecause, testing_metrics, residency_testing_metrics, \ stable_perf_counters, \ - PassFail, badResult, memoize + PassFail, badResult, memoize, str_removeprefix from term_color import Color, colored import testutil from cpu_features import have_cpu_feature @@ -1792,7 +1792,7 @@ async def do_test(name: TestName, if opts.expect not in ['pass', 'fail', 'missing-lib']: framework_fail(name, way, 'bad expected ' + opts.expect) - directory = re.sub(r'^\.[/\\]', '', str(opts.testdir)) + directory = str_removeprefix(str_removeprefix(str(opts.testdir), './'), '.\\') if way in opts.fragile_ways: if_verbose(1, '*** fragile test %s resulted in %s' % (full_name, 'pass' if result.passed else 'fail')) @@ -1830,7 +1830,7 @@ async def do_test(name: TestName, # if found and instead have the testsuite decide on what to do # with the output. def override_options(pre_cmd): - if config.verbose >= 5 and bool(re.match(r'\$make', pre_cmd, re.I)): + if config.verbose >= 5 and pre_cmd.lower().startswith('$make'): return pre_cmd.replace(' -s' , '') \ .replace('--silent', '') \ .replace('--quiet' , '') @@ -1843,7 +1843,7 @@ def framework_fail(name: Optional[TestName], way: Optional[WayName], reason: str # so we need to take care not to blow up with the wrong way # and report the actual reason for the failure. try: - directory = re.sub(r'^\.[/\\]', '', str(opts.testdir)) + directory = str_removeprefix(str_removeprefix(str(opts.testdir), './'), '.\\') except: directory = '' full_name = '%s(%s)' % (name, way) @@ -1856,7 +1856,7 @@ def framework_fail(name: Optional[TestName], way: Optional[WayName], reason: str def framework_warn(name: TestName, way: WayName, reason: str) -> None: opts = getTestOpts() - directory = re.sub(r'^\.[/\\]', '', str(opts.testdir)) + directory = str_removeprefix(str_removeprefix(str(opts.testdir), './'), '.\\') full_name = name + '(' + way + ')' if_verbose(1, '*** framework warning for %s %s ' % (full_name, reason)) t.framework_warnings.append(TestResult(directory, name, reason, way)) @@ -2550,7 +2550,7 @@ def split_file(in_fn: Path, delimiter: str, out1_fn: Path, out2_fn: Path): with out1_fn.open('w', encoding='utf8', newline='') as out1: with out2_fn.open('w', encoding='utf8', newline='') as out2: line = infile.readline() - while re.sub(r'^\s*','',line) != delimiter and line != '': + while line.lstrip() != delimiter and line != '': out1.write(line) line = infile.readline() @@ -2933,6 +2933,14 @@ def normalise_callstacks(s: str) -> str: tyCon_re = re.compile(r'TyCon\s*\d+\#\#\d?\d?\s*\d+\#\#\d?\d?\s*', flags=re.MULTILINE) +def drop_lines_containing(s: str, needle: str) -> str: + """ + Drop lines from `s` which contain `needle`. + """ + if needle not in s: + return s + return ''.join(line for line in s.splitlines(keepends=True) if needle not in line) + def normalise_type_reps(s: str) -> str: """ Normalise out fingerprints from Typeable TyCon representations """ return re.sub(tyCon_re, 'TyCon FINGERPRINT FINGERPRINT ', s) @@ -2944,8 +2952,8 @@ def normalise_errmsg(s: str) -> str: s = s.replace('ld: 0706-027 The -x flag is ignored.\n', '') # remove " error:" and lower-case " Warning:" to make patch for # trac issue #10021 smaller - s = modify_lines(s, lambda l: re.sub(' error:', '', l)) - s = modify_lines(s, lambda l: re.sub(' Warning:', ' warning:', l)) + s = modify_lines(s, lambda l: l.replace(' error:', '')) + s = modify_lines(s, lambda l: l.replace(' Warning:', ' warning:')) s = normalise_callstacks(s) s = normalise_type_reps(s) @@ -2960,7 +2968,7 @@ def normalise_errmsg(s: str) -> str: # a target prefix (e.g. `aarch64-linux-gnu-ghc`) # * On Windows the executable name may mention the # versioned name (e.g. `ghc-9.2.1`) - s = re.sub(Path(config.compiler).name + ':', 'ghc:', s) + s = s.replace(Path(config.compiler).name + ':', 'ghc:') # If somefile ends in ".exe" or ".exe:", zap ".exe" (for Windows) # the colon is there because it appears in error messages; this @@ -2973,11 +2981,13 @@ def normalise_errmsg(s: str) -> str: s = re.sub(r'([^\s])\.jsexe', r'\1', s) # hpc executable is given ghc suffix - s = re.sub('hpc-ghc', 'hpc', s) + s = s.replace('hpc-ghc', 'hpc') # The inplace ghc's are called ghc-stage[123] to avoid filename # collisions, so we need to normalise that to just "ghc" - s = re.sub('ghc-stage[123]', 'ghc', s) + s = (s.replace('ghc-stage1', 'ghc') + .replace('ghc-stage2', 'ghc') + .replace('ghc-stage3', 'ghc')) # Remove platform prefix (e.g. javascript-unknown-ghcjs) for cross-compiled tools # (ghc, ghc-pkg, unlit, etc.) s = re.sub(r'\w+(-\w+)*-ghc', 'ghc', s) @@ -3000,7 +3010,7 @@ def normalise_errmsg(s: str) -> str: # Also filter out bullet characters. This is because bullets are used to # separate error sections, and tests shouldn't be sensitive to how the # the division happens. - bullet = '•'.encode('utf8') if isinstance(s, bytes) else '•' + bullet = '•' s = s.replace(bullet, '') # Windows only, this is a bug in hsc2hs but it is preventing @@ -3015,19 +3025,19 @@ def normalise_errmsg(s: str) -> str: s = modify_lines(s, lambda l: re.sub(r'^(.+)warning: (.+): unsupported GNU_PROPERTY_TYPE (?:\(5\) )?type: 0xc000000(.*)$', '', l)) s = re.sub(r'ld: warning: passed .* min versions \(.*\) for platform macOS. Using [\.0-9]+.','',s) - s = re.sub('ld: warning: -sdk_version and -platform_version are not compatible, ignoring -sdk_version','',s) + s = s.replace('ld: warning: -sdk_version and -platform_version are not compatible, ignoring -sdk_version', '') # ignore superfluous dylibs passed to the linker. - s = re.sub('ld: warning: .*, ignoring unexpected dylib file\n','',s) + s = drop_lines_containing(s, 'ignoring unexpected dylib file') # ignore LLVM Version mismatch garbage; this will just break tests. - s = re.sub('You are using an unsupported version of LLVM!.*\n','',s) - s = re.sub('Currently only [\\.0-9]+ is supported. System LLVM version: [\\.0-9]+.*\n','',s) - s = re.sub('We will try though\\.\\.\\..*\n','',s) + s = drop_lines_containing(s, 'You are using an unsupported version of LLVM!') + s = drop_lines_containing(s, 'System LLVM version:') + s = drop_lines_containing(s, 'We will try though...') # ignore warning about strip invalidating signatures - s = re.sub('.*strip: changes being made to the file will invalidate the code signature in.*\n','',s) + s = drop_lines_containing(s, 'strip: changes being made to the file will invalidate the code signature in') # clang may warn about unused argument when used as assembler - s = re.sub('.*warning: argument unused during compilation:.*\n', '', s) + s = drop_lines_containing(s, 'warning: argument unused during compilation:') # Emscripten displays cache info and old emcc doesn't support EMCC_LOGGING=0 - s = re.sub('cache:INFO: .*\n', '', s) + s = drop_lines_containing(s, 'cache:INFO:') # Old emcc warns when we export HEAP8 but new one requires it (see #26290) s = s.replace('warning: invalid item in EXPORTED_RUNTIME_METHODS: HEAP8\nwarning: invalid item in EXPORTED_RUNTIME_METHODS: HEAPU8\nemcc: warning: warnings in JS library compilation [-Wjs-compiler]\n','') @@ -3050,7 +3060,7 @@ def normalise_prof (s: str) -> str: # The next step assumes none of the fields have no spaces in, which is broke # when the src = <no location info> - s = re.sub('no location info','no-location-info', s) + s = s.replace('no location info', 'no-location-info') # Source locations from internal libraries, remove the source location # > libraries/ghc-internal/src/path/Foo.hs:204:1-18 @@ -3103,21 +3113,21 @@ def normalise_prof (s: str) -> str: return s def normalise_slashes_( s: str ) -> str: - s = re.sub(r'\\', '/', s) - s = re.sub(r'//', '/', s) + s = s.replace('\\', '/') + s = s.replace('//', '/') return s def normalise_exe_( s: str ) -> str: - s = re.sub(r'\.exe', '', s) - s = re.sub(r'\.wasm', '', s) - s = re.sub(r'\.jsexe', '', s) + s = s.replace('.exe', '') + s = s.replace('.wasm', '') + s = s.replace('.jsexe', '') return s def normalise_output( s: str ) -> str: # remove " error:" and lower-case " Warning:" to make patch for # trac issue #10021 smaller - s = modify_lines(s, lambda l: re.sub(' error:', '', l)) - s = modify_lines(s, lambda l: re.sub(' Warning:', ' warning:', l)) + s = modify_lines(s, lambda l: l.replace(' error:', '')) + s = modify_lines(s, lambda l: l.replace(' Warning:', ' warning:')) # Remove a .exe extension (for Windows) # and .wasm extension (for the Wasm backend) # and .jsexe extension (for the JS backend) @@ -3129,19 +3139,19 @@ def normalise_output( s: str ) -> str: s = normalise_type_reps(s) # ghci outputs are pretty unstable with -fexternal-dynamic-refs, which is # requires for -fPIC - s = re.sub(' -fexternal-dynamic-refs\n','',s) + s = s.replace(' -fexternal-dynamic-refs\n', '') s = re.sub(r'ld: warning: passed .* min versions \(.*\) for platform macOS. Using [\.0-9]+.','',s) - s = re.sub('ld: warning: -sdk_version and -platform_version are not compatible, ignoring -sdk_version','',s) + s = s.replace('ld: warning: -sdk_version and -platform_version are not compatible, ignoring -sdk_version', '') # ignore superfluous dylibs passed to the linker. - s = re.sub('ld: warning: .*, ignoring unexpected dylib file\n','',s) + s = drop_lines_containing(s, 'ignoring unexpected dylib file') # ignore LLVM Version mismatch garbage; this will just break tests. - s = re.sub('You are using an unsupported version of LLVM!.*\n','',s) - s = re.sub('Currently only [\\.0-9]+ is supported. System LLVM version: [\\.0-9]+.*\n','',s) - s = re.sub('We will try though\\.\\.\\..*\n','',s) + s = drop_lines_containing(s, 'You are using an unsupported version of LLVM!') + s = drop_lines_containing(s, 'System LLVM version:') + s = drop_lines_containing(s, 'We will try though...') # ignore warning about strip invalidating signatures - s = re.sub('.*strip: changes being made to the file will invalidate the code signature in.*\n','',s) + s = drop_lines_containing(s, 'strip: changes being made to the file will invalidate the code signature in') # clang may warn about unused argument when used as assembler - s = re.sub('.*warning: argument unused during compilation:.*\n', '', s) + s = drop_lines_containing(s, 'warning: argument unused during compilation:') # strip the cross prefix if any s = re.sub(r'\w+(-\w+)*-ghc', 'ghc', s) ===================================== testsuite/driver/testutil.py ===================================== @@ -40,6 +40,12 @@ def strip_quotes(s: str) -> str: # Don't wrap commands to subprocess.call/Popen in quotes. return s.strip('\'"') +# Python 3.7 compatibility shim for str.removeprefix (added in Python 3.9). +def str_removeprefix(s: str, prefix: str) -> str: + if s.startswith(prefix): + return s.replace(prefix, '', 1) + return s + def str_warn(s: str) -> str: return colored(Color.YELLOW, s) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/ca79475f6b4dfba991e2c933bac9c22d... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/ca79475f6b4dfba991e2c933bac9c22d... 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