| # pylint: disable=g-bad-file-header |
| # Copyright 2016 The Bazel Authors. All rights reserved. |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| """Base library for configuring the C++ toolchain.""" |
| |
| def resolve_labels(repository_ctx, labels): |
| """Resolves a collection of labels to their paths. |
| |
| Label resolution can cause the evaluation of Starlark functions to restart. |
| For functions with side-effects (like the auto-configuration functions, which |
| inspect the system and touch the file system), such restarts are costly. |
| We cannot avoid the restarts, but we can minimize their penalty by resolving |
| all labels upfront. |
| |
| Among other things, doing less work on restarts can cut analysis times by |
| several seconds and may also prevent tickling kernel conditions that cause |
| build failures. See https://github.com/bazelbuild/bazel/issues/5196 for |
| more details. |
| |
| Args: |
| repository_ctx: The context with which to resolve the labels. |
| labels: Labels to be resolved expressed as a list of strings. |
| |
| Returns: |
| A dictionary with the labels as keys and their paths as values. |
| """ |
| return dict([(label, repository_ctx.path(Label(label))) for label in labels]) |
| |
| def escape_string(arg): |
| """Escape percent sign (%) in the string so it can appear in the Crosstool.""" |
| if arg != None: |
| return str(arg).replace("%", "%%") |
| else: |
| return None |
| |
| def split_escaped(string, delimiter): |
| """Split string on the delimiter unless %-escaped. |
| |
| Examples: |
| Basic usage: |
| split_escaped("a:b:c", ":") -> [ "a", "b", "c" ] |
| |
| Delimeter that is not supposed to be splitten on has to be %-escaped: |
| split_escaped("a%:b", ":") -> [ "a:b" ] |
| |
| Literal % can be represented by escaping it as %%: |
| split_escaped("a%%b", ":") -> [ "a%b" ] |
| |
| Consecutive delimiters produce empty strings: |
| split_escaped("a::b", ":") -> [ "a", "", "", "b" ] |
| |
| Args: |
| string: The string to be split. |
| delimiter: Non-empty string not containing %-sign to be used as a |
| delimiter. |
| |
| Returns: |
| A list of substrings. |
| """ |
| if delimiter == "": |
| fail("Delimiter cannot be empty") |
| if delimiter.find("%") != -1: |
| fail("Delimiter cannot contain %-sign") |
| |
| i = 0 |
| result = [] |
| accumulator = [] |
| length = len(string) |
| delimiter_length = len(delimiter) |
| |
| if not string: |
| return [] |
| |
| # Iterate over the length of string since Starlark doesn't have while loops |
| for _ in range(length): |
| if i >= length: |
| break |
| if i + 2 <= length and string[i:i + 2] == "%%": |
| accumulator.append("%") |
| i += 2 |
| elif (i + 1 + delimiter_length <= length and |
| string[i:i + 1 + delimiter_length] == "%" + delimiter): |
| accumulator.append(delimiter) |
| i += 1 + delimiter_length |
| elif i + delimiter_length <= length and string[i:i + delimiter_length] == delimiter: |
| result.append("".join(accumulator)) |
| accumulator = [] |
| i += delimiter_length |
| else: |
| accumulator.append(string[i]) |
| i += 1 |
| |
| # Append the last group still in accumulator |
| result.append("".join(accumulator)) |
| return result |
| |
| def auto_configure_fail(msg): |
| """Output failure message when auto configuration fails.""" |
| red = "\033[0;31m" |
| no_color = "\033[0m" |
| fail("\n%sAuto-Configuration Error:%s %s\n" % (red, no_color, msg)) |
| |
| def auto_configure_warning(msg): |
| """Output warning message during auto configuration.""" |
| yellow = "\033[1;33m" |
| no_color = "\033[0m" |
| print("\n%sAuto-Configuration Warning:%s %s\n" % (yellow, no_color, msg)) |
| |
| def get_env_var(repository_ctx, name, default = None, enable_warning = True): |
| """Find an environment variable in system path. Doesn't %-escape the value!""" |
| if name in repository_ctx.os.environ: |
| return repository_ctx.os.environ[name] |
| if default != None: |
| if enable_warning: |
| auto_configure_warning("'%s' environment variable is not set, using '%s' as default" % (name, default)) |
| return default |
| auto_configure_fail("'%s' environment variable is not set" % name) |
| |
| def which(repository_ctx, cmd, default = None): |
| """A wrapper around repository_ctx.which() to provide a fallback value. Doesn't %-escape the value!""" |
| result = repository_ctx.which(cmd) |
| return default if result == None else str(result) |
| |
| def which_cmd(repository_ctx, cmd, default = None): |
| """Find cmd in PATH using repository_ctx.which() and fail if cannot find it. Doesn't %-escape the cmd!""" |
| result = repository_ctx.which(cmd) |
| if result != None: |
| return str(result) |
| path = get_env_var(repository_ctx, "PATH") |
| if default != None: |
| auto_configure_warning("Cannot find %s in PATH, using '%s' as default.\nPATH=%s" % (cmd, default, path)) |
| return default |
| auto_configure_fail("Cannot find %s in PATH, please make sure %s is installed and add its directory in PATH.\nPATH=%s" % (cmd, cmd, path)) |
| return str(result) |
| |
| def execute( |
| repository_ctx, |
| command, |
| environment = None, |
| expect_failure = False): |
| """Execute a command, return stdout if succeed and throw an error if it fails. Doesn't %-escape the result!""" |
| if environment: |
| result = repository_ctx.execute(command, environment = environment) |
| else: |
| result = repository_ctx.execute(command) |
| if expect_failure != (result.return_code != 0): |
| if expect_failure: |
| auto_configure_fail( |
| "expected failure, command %s, stderr: (%s)" % ( |
| command, |
| result.stderr, |
| ), |
| ) |
| else: |
| auto_configure_fail( |
| "non-zero exit code: %d, command %s, stderr: (%s)" % ( |
| result.return_code, |
| command, |
| result.stderr, |
| ), |
| ) |
| stripped_stdout = result.stdout.strip() |
| if not stripped_stdout: |
| auto_configure_fail( |
| "empty output from command %s, stderr: (%s)" % (command, result.stderr), |
| ) |
| return stripped_stdout |
| |
| def get_cpu_value(repository_ctx): |
| """Compute the cpu_value based on the OS name. Doesn't %-escape the result!""" |
| os_name = repository_ctx.os.name.lower() |
| if os_name.startswith("mac os"): |
| # Check if we are on x86_64 or arm64 and return the corresponding cpu value. |
| result = repository_ctx.execute(["uname", "-m"]) |
| return "darwin" + ("_arm64" if result.stdout.strip() == "arm64" else "") |
| if os_name.find("freebsd") != -1: |
| return "freebsd" |
| if os_name.find("openbsd") != -1: |
| return "openbsd" |
| if os_name.find("windows") != -1: |
| return "x64_windows" |
| |
| # Use uname to figure out whether we are on x86_32 or x86_64 |
| result = repository_ctx.execute(["uname", "-m"]) |
| if result.stdout.strip() in ["power", "ppc64le", "ppc", "ppc64"]: |
| return "ppc" |
| if result.stdout.strip() in ["s390x"]: |
| return "s390x" |
| if result.stdout.strip() in ["mips64"]: |
| return "mips64" |
| if result.stdout.strip() in ["riscv64"]: |
| return "riscv64" |
| if result.stdout.strip() in ["arm", "armv7l"]: |
| return "arm" |
| if result.stdout.strip() in ["aarch64"]: |
| return "aarch64" |
| return "k8" if result.stdout.strip() in ["amd64", "x86_64", "x64"] else "piii" |
| |
| def is_cc_configure_debug(repository_ctx): |
| """Returns True if CC_CONFIGURE_DEBUG is set to 1.""" |
| env = repository_ctx.os.environ |
| return "CC_CONFIGURE_DEBUG" in env and env["CC_CONFIGURE_DEBUG"] == "1" |
| |
| def build_flags(flags): |
| """Convert `flags` to a string of flag fields.""" |
| return "\n".join([" flag: '" + flag + "'" for flag in flags]) |
| |
| def get_starlark_list(values): |
| """Convert a list of string into a string that can be passed to a rule attribute.""" |
| if not values: |
| return "" |
| return "\"" + "\",\n \"".join(values) + "\"" |
| |
| def auto_configure_warning_maybe(repository_ctx, msg): |
| """Output warning message when CC_CONFIGURE_DEBUG is enabled.""" |
| if is_cc_configure_debug(repository_ctx): |
| auto_configure_warning(msg) |
| |
| def write_builtin_include_directory_paths(repository_ctx, cc, directories, file_suffix = ""): |
| """Generate output file named 'builtin_include_directory_paths' in the root of the repository.""" |
| if get_env_var(repository_ctx, "BAZEL_IGNORE_SYSTEM_HEADERS_VERSIONS", "0", False) == "1": |
| repository_ctx.file( |
| "builtin_include_directory_paths" + file_suffix, |
| """This file is generated by cc_configure and normally contains builtin include directories |
| that C++ compiler reported. But because BAZEL_IGNORE_SYSTEM_HEADERS_VERSIONS was set to 1, |
| header include directory paths are intentionally not put there. |
| """, |
| ) |
| else: |
| repository_ctx.file( |
| "builtin_include_directory_paths" + file_suffix, |
| """This file is generated by cc_configure and contains builtin include directories |
| that %s reported. This file is a dependency of every compilation action and |
| changes to it will be reflected in the action cache key. When some of these |
| paths change, Bazel will make sure to rerun the action, even though none of |
| declared action inputs or the action commandline changes. |
| |
| %s |
| """ % (cc, "\n".join(directories)), |
| ) |
