[llvm] [CI] Add Python Script for Computing Projects/Runtimes to Test (PR #132634)

[Nathan Gauër via llvm-commits]

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+# 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
+"""Computes the list of projects that need to be tested from a diff.
+
+Does some things, spits out a list of projects.
+"""
+
+from collections.abc import Set
+import pathlib
+import platform
+import sys
+
+PROJECT_DEPENDENCIES = {
+    "llvm": set(),
+    "clang": {"llvm"},
+    "bolt": {"clang", "lld", "llvm"},
+    "clang-tools-extra": {"clang", "llvm"},
+    "compiler-rt": {"clang", "lld"},
+    "libc": {"clang", "lld"},
+    "openmp": {"clang", "lld"},
+    "flang": {"llvm", "clang"},
+    "lldb": {"llvm", "clang"},
+    "libclc": {"llvm", "clang"},
+    "lld": {"llvm"},
+    "mlir": {"llvm"},
+    "polly": {"llvm"},
+}
+
+DEPENDENTS_TO_TEST = {
+    "llvm": {"bolt", "clang", "clang-tools-extra", "lld", "lldb", "mlir", "polly"},
+    "lld": {"bolt", "cross-project-tests"},
+    "clang": {"clang-tools-extra", "compiler-rt", "cross-project-tests"},
+    "clang-tools-extra": {"libc"},
+    "mlir": {"flang"},
+}
+
+DEPENDENT_RUNTIMES_TO_TEST = {"clang": {"libcxx", "libcxxabi", "libunwind"}}
+
+EXCLUDE_LINUX = {
+    "cross-project-tests",  # Tests are failing.
+    "openmp",  # https://github.com/google/llvm-premerge-checks/issues/410
+}
+
+EXCLUDE_WINDOWS = {
+    "cross-project-tests",  # Tests are failing.
+    "compiler-rt",  # Tests are taking too long.
+    "openmp",  # Does not detect perl installation.
+    "libc",  # No Windows Support.
+    "lldb",  # Custom environment requirements.
+    "bolt",  # No Windows Support.
+}
+
+EXCLUDE_MAC = {
+    "bolt",
+    "compiler-rt",
+    "cross-project-tests",
+    "flang",
+    "libc",
+    "libcxx",
+    "libcxxabi",
+    "libunwind",
+    "lldb",
+    "openmp",
+    "polly",
+}
+
+PROJECT_CHECK_TARGETS = {
+    "clang-tools-extra": "check-clang-tools",
+    "compiler-rt": "check-compiler-rt",
+    "cross-project-tests": "check-cross-project",
+    "libcxx": "check-cxx",
+    "libcxxabi": "check-cxxabi",
+    "libunwind": "check-unwind",
+    "lldb": "check-lldb",
+    "llvm": "check-llvm",
+    "clang": "check-clang",
+    "bolt": "check-bolt",
+    "lld": "check-lld",
+    "flang": "check-flang",
+    "libc": "check-libc",
+    "lld": "check-lld",
+    "lldb": "check-lldb",
+    "mlir": "check-mlir",
+    "openmp": "check-openmp",
+    "polly": "check-polly",
+}
+
+
+def _add_dependencies(projects: Set[str]) -> Set[str]:
+    projects_with_dependents = set(projects)
+    current_projects_count = 0
+    while current_projects_count != len(projects_with_dependents):
+        current_projects_count = len(projects_with_dependents)
+        for project in list(projects_with_dependents):
+            if project not in PROJECT_DEPENDENCIES:
+                continue
+            projects_with_dependents.update(PROJECT_DEPENDENCIES[project])
+    return projects_with_dependents
+
+
+def _compute_projects_to_test(modified_projects: Set[str], platform: str) -> Set[str]:
+    projects_to_test = set()
+    for modified_project in modified_projects:
+        # Skip all projects where we cannot run tests.
+        if modified_project not in PROJECT_CHECK_TARGETS:
+            continue
+        projects_to_test.add(modified_project)
+        if modified_project not in DEPENDENTS_TO_TEST:
+            continue
+        projects_to_test.update(DEPENDENTS_TO_TEST[modified_project])
+    if platform == "Linux":
+        for to_exclude in EXCLUDE_LINUX:
+            if to_exclude in projects_to_test:
+                projects_to_test.remove(to_exclude)
+    elif platform == "Windows":
+        for to_exclude in EXCLUDE_WINDOWS:
+            if to_exclude in projects_to_test:
+                projects_to_test.remove(to_exclude)
+    elif platform == "Darwin":
+        for to_exclude in EXCLUDE_MAC:
+            if to_exclude in projects_to_test:
+                projects_to_test.remove(to_exclude)
+    else:
+        raise ValueError("Unexpected platform.")
+    return projects_to_test
+
+
+def _compute_projects_to_build(projects_to_test: Set[str]) -> Set[str]:
+    return _add_dependencies(projects_to_test)
+
+
+def _compute_project_check_targets(projects_to_test: Set[str]) -> Set[str]:
+    check_targets = set()
+    for project_to_test in projects_to_test:
+        if project_to_test not in PROJECT_CHECK_TARGETS:
+            continue
+        check_targets.add(PROJECT_CHECK_TARGETS[project_to_test])
+    return check_targets
+
+
+def _compute_runtimes_to_test(projects_to_test: Set[str]) -> Set[str]:
+    runtimes_to_test = set()
+    for project_to_test in projects_to_test:
+        if project_to_test not in DEPENDENT_RUNTIMES_TO_TEST:
+            continue
+        runtimes_to_test.update(DEPENDENT_RUNTIMES_TO_TEST[project_to_test])
+    return runtimes_to_test
+
+
+def _compute_runtime_check_targets(runtimes_to_test: Set[str]) -> Set[str]:
+    check_targets = set()
+    for runtime_to_test in runtimes_to_test:
+        check_targets.add(PROJECT_CHECK_TARGETS[runtime_to_test])
+    return check_targets
+
+
+def _get_modified_projects(modified_files: list[str]) -> Set[str]:
+    modified_projects = set()
+    for modified_file in modified_files:
+        modified_projects.add(pathlib.Path(modified_file).parts[0])
+    return modified_projects
+
+
+def get_env_variables(modified_files: list[str], platform: str) -> Set[str]:
+    modified_projects = _get_modified_projects(modified_files)
+    projects_to_test = _compute_projects_to_test(modified_projects, platform)
+    projects_to_build = _compute_projects_to_build(projects_to_test)
+    projects_check_targets = _compute_project_check_targets(projects_to_test)
+    runtimes_to_test = _compute_runtimes_to_test(projects_to_test)
+    runtimes_check_targets = _compute_runtime_check_targets(runtimes_to_test)
+    return {
+        "projects_to_build": ";".join(sorted(projects_to_build)),
+        "project_check_targets": " ".join(sorted(projects_check_targets)),
+        "runtimes_to_build": ";".join(sorted(runtimes_to_test)),
+        "runtimes_check_targets": " ".join(sorted(runtimes_check_targets)),
----------------
Keenuts wrote:

A comment is fine.

> I think it's reasonably clear that projects_to_build and runtimes_to_build are going to be passed as CMake arguments

When you know how the CI works. If you don't you see a scripts which purpose is to turn a list of into a list of targets/projects, the use then depends on the caller.

https://github.com/llvm/llvm-project/pull/132634