Files
codex/patches/rules_rust_declared_msvc_linker.patch
T
zbarsky-openai 1099fe0694 Use hermetic LLVM for Windows MSVC Bazel builds (#60507)
## Why

Windows MSVC builds relied on installed C++ toolchains, and V8 snapshot generation required native Windows execution. Cross-compiling V8 also needs a Windows snapshot generator to preserve Windows unwind metadata.

## What changed

- Use the registered hermetic LLVM toolchain and declared Microsoft SDK for Windows MSVC builds, with static CRT linkage and the toolchain's declared `lld-link` for Rust.
- Run Windows V8 snapshot generators natively or through `rules_wine` on Linux, preserving target CPU, OS, and sandbox settings. Keep separate archive and binding pairs for the workspace's ISO stdio ABI and the distributed MSVC stdio ABI.
- Update build dependencies and bindgen, scope V8's Chromium libc++ settings to its own targets, and adapt native voice dependencies for clang-cl and Windows ARM64.
- Build SQLite directly with Bazel and give `openssl-sys` an explicit build using Bazel's OpenSSL.
- Remove build-worker source-directory dependencies from Bazel resource lookup, schema output discovery, and snapshot paths; embed assets in debug builds as well.

GitOrigin-RevId: fd224d9d28d73a67baf90f6d73c6079d60f20351
2026-11-10 03:02:25 +00:00

108 lines
5.2 KiB
Diff

# rules_rust PR #92, commit 100616343e949f6744c5f01733cc42bf36c86d5e.
# Use the selected C++ toolchain's declared lld-link for rustc.
# Cargo retains clang-cl; explicit Rust linker preferences remain unchanged.
diff --git a/rust/private/rustc.bzl b/rust/private/rustc.bzl
index 5b206a6c0..a79bb6108 100644
--- a/rust/private/rustc.bzl
+++ b/rust/private/rustc.bzl
@@ -412,6 +412,7 @@ _LinkerConfigInfo = provider(fields = [
"action_name",
"feature_configuration",
"is_direct_driver",
+ "msvc_lld_link",
"rpaths",
"rust_linker",
"target_abi",
@@ -420,7 +421,14 @@ _LinkerConfigInfo = provider(fields = [
"variables",
])
-def _get_linker_config(ctx, crate_type, toolchain, cc_toolchain, feature_configuration, rpaths, add_flags_for_binary):
+def _get_cc_linker_files(cc_toolchain):
+ if not cc_toolchain:
+ return depset()
+ if hasattr(cc_toolchain, "_linker_files"):
+ return cc_toolchain._linker_files
+ return cc_toolchain.linker_files()
+
+def _get_linker_config(ctx, crate_type, toolchain, cc_toolchain, feature_configuration, rpaths, add_flags_for_binary, for_rustc = False):
user_link_flags = get_cc_user_link_flags(ctx)
cc_linker = None
@@ -463,6 +471,19 @@ def _get_linker_config(ctx, crate_type, toolchain, cc_toolchain, feature_configu
if use_rust_linker and not toolchain.linker:
fail("No linker available for rustc. Either `rust_toolchain.linker` must be set or a `cc_toolchain` configured for the current configuration.")
+ msvc_lld_link = None
+ if for_rustc and not use_rust_linker and toolchain.target_os == "windows" and toolchain.target_abi == "msvc" and paths.basename(cc_linker).lower() in ("clang-cl", "clang-cl.exe"):
+ # rustc's MSVC interface sends LINK arguments, not clang-cl arguments.
+ # Keep Cargo's C/C++ driver unchanged and use only a declared sibling.
+ executable = "lld-link.exe" if cc_linker.lower().endswith(".exe") else "lld-link"
+ linker_path = paths.join(paths.dirname(cc_linker), executable)
+ for file in _get_cc_linker_files(cc_toolchain).to_list():
+ if file.path == linker_path:
+ msvc_lld_link = file
+ break
+ if not msvc_lld_link:
+ fail("Rust MSVC linking requires {} in cc_toolchain.linker_files when the C++ linker is {}. Alternatively, configure a direct MSVC linker in the Rust toolchain and set linker_preference = \"rust\".".format(linker_path, cc_linker))
+
# Keep CcToolchainVariables and the Rust linker File until map_each runs so
# cc_common and File.path use the Rustc action's path mapper.
return _LinkerConfigInfo(
@@ -470,7 +491,8 @@ def _get_linker_config(ctx, crate_type, toolchain, cc_toolchain, feature_configu
action_name = action_name,
variables = link_variables,
rust_linker = toolchain.linker if use_rust_linker else None,
- is_direct_driver = use_rust_linker and toolchain.linker_type == "direct",
+ msvc_lld_link = msvc_lld_link,
+ is_direct_driver = bool(msvc_lld_link) or (use_rust_linker and toolchain.linker_type == "direct"),
target_abi = toolchain.target_abi,
target_arch = toolchain.target_arch,
target_os = toolchain.target_os,
@@ -480,6 +502,8 @@ def _get_linker_config(ctx, crate_type, toolchain, cc_toolchain, feature_configu
def _get_linker_path(linker_config):
if linker_config.rust_linker:
return linker_config.rust_linker.path
+ if linker_config.msvc_lld_link:
+ return linker_config.msvc_lld_link.path
return cc_common.get_tool_for_action(
feature_configuration = linker_config.feature_configuration,
action_name = linker_config.action_name,
@@ -538,7 +562,7 @@ def _get_linker_args(linker_config):
variables = linker_config.variables,
))
- if linker_config.rust_linker:
+ if linker_config.rust_linker or linker_config.msvc_lld_link:
# Make sure we include RPATHs for Rust ABI dylibs even when no cc_toolchain.
if linker_config.variables == None and linker_config.rpaths:
for rpath in linker_config.rpaths.to_list():
@@ -915,17 +939,7 @@ def collect_inputs(
"""
linker_script = getattr(file, "linker_script", None)
- # TODO: As of writing this comment Bazel used Java CcToolchainInfo.
- # However there is ongoing work to rewrite provider in Starlark.
- # rules_rust is not coupled with Bazel release. Remove conditional and change to
- # _linker_files once Starlark CcToolchainInfo is visible to Bazel.
- # https://github.com/bazelbuild/rules_rust/issues/2425
- if not cc_toolchain:
- linker_depset = depset()
- elif hasattr(cc_toolchain, "_linker_files"):
- linker_depset = cc_toolchain._linker_files
- else:
- linker_depset = cc_toolchain.linker_files()
+ linker_depset = _get_cc_linker_files(cc_toolchain)
compilation_mode = ctx.var["COMPILATION_MODE"]
use_pic = should_use_pic(
@@ -1586,6 +1600,7 @@ def construct_arguments(
feature_configuration,
rpaths,
add_flags_for_binary = add_flags_for_binary,
+ for_rustc = True,
)
ld_is_direct_driver = linker_config.is_direct_driver