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Support deterministic mode when using a version of libtool that suppo…
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…rts it.

Xcode 10.2 adds a new flag `-D` to libtool that sets archive contents'
user ids, group ids, dates, and file modes to reasonable defaults.

This patch adds this new flag to all libtool actions to when they're
built with a version of libtool that supports this mode, to ensure
hemertic results for linking actions. Note that this new flag covers the
functionality of the `ZERO_AR_DATE` environment variable, but this
variable is still being left in the libtool wrapper for
backward-compatibility with older versions.

Fixes bazelbuild#10886.

RENOTES: None.

Closes bazelbuild#11840.

PiperOrigin-RevId: 327086633
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@thii @copybara-github
thii authored and copybara-github committed Aug 17, 2020
1 parent 05f137a commit d483d6f
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Showing 2 changed files with 47 additions and 18 deletions.
2 changes: 1 addition & 1 deletion tools/objc/libtool.sh
View file
Original file line number Diff line number Diff line change
Expand Up @@ -85,7 +85,7 @@ while [[ $# -gt 0 ]]; do
OUTPUTFILE="${ARG}"
;;
# Flags with no args
-static|-s|-a|-c|-L|-T|-no_warning_for_no_symbols)
-static|-s|-a|-c|-L|-T|-D|-no_warning_for_no_symbols)
ARGS+=("${ARG}")
;;
# Single-arg flags
Expand Down
63 changes: 46 additions & 17 deletions tools/osx/crosstool/cc_toolchain_config.bzl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,6 +30,30 @@ load(
)
load("@bazel_tools//tools/build_defs/cc:action_names.bzl", "ACTION_NAMES")

# The Xcode version from which that has support for deterministic mode
_SUPPORTS_DETERMINISTIC_MODE = "10.2"

def _compare_versions(dv1, v2):
"""Return value is <0, 0, >0 depending on DottedVersion dv1 comparison to string v2."""
return dv1.compare_to(apple_common.dotted_version(v2))

def _can_use_deterministic_libtool(ctx):
"""Returns `True` if the current version of `libtool` has support for
deterministic mode, and `False` otherwise."""
xcode_config = ctx.attr._xcode_config[apple_common.XcodeVersionConfig]
xcode_version = xcode_config.xcode_version()
if _compare_versions(xcode_version, _SUPPORTS_DETERMINISTIC_MODE) >= 0:
return True
else:
return False

def _deterministic_libtool_flags(ctx):
"""Returns additional `libtool` flags to enable deterministic mode, if they
are available."""
if _can_use_deterministic_libtool(ctx):
return ["-D"]
return []

def _impl(ctx):
if (ctx.attr.cpu == "darwin_x86_64"):
toolchain_identifier = "darwin_x86_64"
Expand Down Expand Up @@ -1794,7 +1818,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-filelist",
Expand Down Expand Up @@ -1825,7 +1849,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-filelist",
Expand Down Expand Up @@ -1857,7 +1881,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-filelist",
Expand Down Expand Up @@ -1888,7 +1912,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-filelist",
Expand Down Expand Up @@ -1919,7 +1943,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-filelist",
Expand Down Expand Up @@ -1950,7 +1974,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-filelist",
Expand Down Expand Up @@ -1982,7 +2006,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-filelist",
Expand Down Expand Up @@ -2016,7 +2040,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-filelist",
Expand Down Expand Up @@ -2798,7 +2822,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-arch_only",
Expand Down Expand Up @@ -2839,7 +2863,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-arch_only",
Expand Down Expand Up @@ -2881,7 +2905,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-arch_only",
Expand Down Expand Up @@ -2922,7 +2946,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-arch_only",
Expand Down Expand Up @@ -2963,7 +2987,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-arch_only",
Expand Down Expand Up @@ -3004,7 +3028,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-arch_only",
Expand Down Expand Up @@ -3046,7 +3070,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-arch_only",
Expand Down Expand Up @@ -3090,7 +3114,7 @@ def _impl(ctx):
flag_set(
flag_groups = [
flag_group(
flags = [
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-arch_only",
Expand Down Expand Up @@ -5003,7 +5027,12 @@ def _impl(ctx):
actions = [ACTION_NAMES.cpp_link_static_library],
flag_groups = [
flag_group(
flags = ["-no_warning_for_no_symbols", "-static", "-o", "%{output_execpath}"],
flags = _deterministic_libtool_flags(ctx) + [
"-no_warning_for_no_symbols",
"-static",
"-o",
"%{output_execpath}",
],
expand_if_available = "output_execpath",
),
],
Expand Down

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