[fuchsia_clang] Symlink clang install directory.
Use top-level symlinks instead of recursive hard-links or copies when
creating the content of the @fuchsia_clang repository. This is made
possible by our change in the 'dependency_file' feature in a previous
CL [1], which allows such paths to work correctly with the paths found
in compiler-generated dependency (.d) files.
This is also an attempt to remove flaky hard-linking issues that
appear when trying to update to Bazel 6, see [2] for an example.
+ Add llvm-strip to the list of compiler prebuilts. Otherwise, some
C++ compile actions would fail with Bazel6.
Bug: 116108
[1] https://fuchsia-review.git.corp.google.com/c/sdk-integration/+/786962
[2] tqr/645770 patchset 2
Change-Id: I87d970560ba30723f44437e9f09244e298951ad0
Reviewed-on: https://fuchsia-review.googlesource.com/c/sdk-integration/+/786964
Reviewed-by: Renato Mangini Dias <mangini@google.com>
Commit-Queue: David Turner <digit@google.com>
diff --git a/bazel_rules_fuchsia/fuchsia/workspace/clang_templates/crosstool_template.BUILD b/bazel_rules_fuchsia/fuchsia/workspace/clang_templates/crosstool_template.BUILD
index a8f225d..c761599 100644
--- a/bazel_rules_fuchsia/fuchsia/workspace/clang_templates/crosstool_template.BUILD
+++ b/bazel_rules_fuchsia/fuchsia/workspace/clang_templates/crosstool_template.BUILD
@@ -36,6 +36,7 @@
"//:bin/clang++",
"//:bin/clang-%{CLANG_VERSION}",
"//:bin/clang-cpp",
+ "//:bin/llvm-strip",
],
)
diff --git a/bazel_rules_fuchsia/fuchsia/workspace/fuchsia_clang_repository.bzl b/bazel_rules_fuchsia/fuchsia/workspace/fuchsia_clang_repository.bzl
index 5c18db9..ce8d428 100644
--- a/bazel_rules_fuchsia/fuchsia/workspace/fuchsia_clang_repository.bzl
+++ b/bazel_rules_fuchsia/fuchsia/workspace/fuchsia_clang_repository.bzl
@@ -22,7 +22,7 @@
ctx.report_progress("Extracting local clang archive")
ctx.extract(archive = ctx.attr.local_archive)
-def _instantiate_from_local_dir(ctx, local_clang, fuchsia_tools_dir):
+def _instantiate_from_local_dir(ctx, local_clang):
# buildifier: disable=print
# local_path can be either a string or Path object.
if type(local_clang) == type("str"):
@@ -30,42 +30,13 @@
ctx.report_progress("Copying local clang from %s" % local_clang)
- # Generate a Python script to hard-link the content of the Clang installation
- # to the repository directory itself.
- #
- # NOTE: hard-linking is not ideal, if the Fuchsia platform checkout
- # changes (e.g. with a `jiri update`, Bazel will not detect changes
- # in the source files used here and will keep using the old toolchain.
- #
- # However, symlinking introduces other issues, because then Bazel C++
- # compile actions will complain about unlisted header dependencies
- # from /path/to/fuchsia/prebuilt/third_party/clang/linux-x64/...
- # paths (not that these are absolute paths to the FUCHSIA_DIR checkout,
- # and not relative to the Bazel execroot).
- #
- # This is because these paths are listed in Clang-generated .d files that
- # are consumed by Bazel, which then verifies that they belong to the
- # directories listed in cxx_builtin_include_directories, and this only
- # contains absolute file paths to the @fuchsia_clang repository directory.
- try_hardlink = True
- _cp_tool = fuchsia_tools_dir + "/cp.sh"
+ # Symlink top-level items from Clang prebuilt install to repository directory
+ # Note that this is possible because our C++ toolchain configuration redefine
+ # the "dependency_file" feature to use relative file paths.
for f in local_clang.readdir():
- # For performance reasons, if a single hardlink operation fails, we
- # switch to regular copy for all the remaining destination directories.
- if try_hardlink:
- result = ctx.execute([_cp_tool, f, ".", "-l", "-n"], quiet = True)
- if result.return_code != 0:
- print("WARNING: cannot create hardlink to local clang files, falling back to regular copy")
- try_hardlink = False
+ ctx.symlink(f, f.basename)
- # This is not an "else" intentionally, since we want to execute regular
- # copy if we couldn't hardlink.
- if not try_hardlink:
- result = ctx.execute([_cp_tool, f, ".", "-n"], quiet = False)
- if result.return_code != 0:
- fail("Cannot copy clang files from %s" % f)
-
-def _instantiate_from_local_fuchsia_tree(ctx, fuchsia_tools_dir):
+def _instantiate_from_local_fuchsia_tree(ctx):
# Copies clang prebuilt from a local Fuchsia platform tree.
local_fuchsia_dir = ctx.os.environ[_LOCAL_FUCHSIA_PLATFORM_BUILD]
local_clang = ctx.path("%s/%s" % (local_fuchsia_dir, _LOCAL_FUCHSIA_CLANG_DIR))
@@ -76,7 +47,7 @@
fail("Expected a single host architecture subdirectory in local clang: %s" % str(local_clang))
local_clang_arch = local_clang_archs[0]
- _instantiate_from_local_dir(ctx, local_clang_arch, fuchsia_tools_dir)
+ _instantiate_from_local_dir(ctx, local_clang_arch)
def _fuchsia_clang_repository_impl(ctx):
# Pre-evaluate paths of templated output files so that the repository does not need to be
@@ -84,8 +55,6 @@
ctx.path("BUILD.bazel")
ctx.path("cc_toolchain_config.bzl")
- fuchsia_tools_dir = str(ctx.path(Label("//fuchsia/tools:BUILD.bazel")).dirname)
-
crosstool_template = Label("//fuchsia/workspace/clang_templates:crosstool_template.BUILD")
toolchain_config_template = Label("//fuchsia/workspace/clang_templates:cc_toolchain_config_template.bzl")
@@ -112,9 +81,9 @@
normalized_os = normalize_os(ctx)
if ctx.attr.local_path:
local_clang = workspace_path(ctx, ctx.attr.local_path)
- _instantiate_from_local_dir(ctx, local_clang, fuchsia_tools_dir)
+ _instantiate_from_local_dir(ctx, local_clang)
elif _LOCAL_FUCHSIA_PLATFORM_BUILD in ctx.os.environ:
- _instantiate_from_local_fuchsia_tree(ctx, fuchsia_tools_dir)
+ _instantiate_from_local_fuchsia_tree(ctx)
elif ctx.attr.local_archive:
_instantiate_local_archive(ctx)
elif ctx.attr.cipd_tag:
