Set indirect linking for non wasm / RISC-V targets

rs/toolchains/BUILD.bazel

@@ -44,6 +44,7 @@ bzl_library(
         ":toolchain_utils",
         "//rs/platforms:triples",
         "//rs/private:bpf_linker_repository",
+        "@bazel_skylib//lib:versions",
         "@default_rust_toolchains//rustc:component_labels.bzl",
         "@rules_rust//rust:bzl_lib",
         "@rules_rust//rust/platform:bzl_lib",

rs/toolchains/declare_rustc_toolchains.bzl

@@ -1,5 +1,6 @@
 """Definitions for declaring Rust compiler toolchains."""
 
+load("@bazel_skylib//lib:versions.bzl", "versions")
 load("@default_rust_toolchains//rustc:component_labels.bzl", "rust_toolchain_component_label")
 load("@rules_rust//rust:rust_toolchain.bzl", "rust_toolchain")
 load("@rules_rust//rust/platform:triple.bzl", _parse_triple = "triple")
@@ -20,6 +21,23 @@ def _rustc_flags_to_select(rustc_flags_by_triple):
         {"//conditions:default": []},
     )
 
+def _default_rustc_flags(version):
+    # Rust >= 1.90 defaults to self-contained LLD for x86_64-unknown-linux-gnu.
+    # When linking via Bazel C++ toolchain wrappers (e.g. cc_wrapper.sh), rustc
+    # fails to recognize the wrapper as a C compiler driver and attempts to invoke
+    # its bundled gcc-ld/rust-lld, failing in hermetic/sandboxed environments where
+    # the undeclared linker is not in the sandbox, or overriding the C++ toolchain's
+    # configured linker. Disabling the LLD linker feature leaves linking entirely to
+    # the Bazel C++ toolchain.
+    # Prior to 1.90, rustc did not default to LLD and the -Clinker-features option did not exist.
+    if _channel(version) == "stable" and not versions.is_at_least("1.90.0", version):
+        return []
+
+    return select({
+        "@rules_rs//rs/platforms/config:x86_64-unknown-linux-gnu": ["-Clinker-features=-lld"],
+        "//conditions:default": [],
+    })
+
 def _component(component, triple, default):
     component = component.get(triple) if type(component) == "dict" else component
     return component or rust_toolchain_component_label(default)
@@ -193,8 +211,8 @@ def declare_rustc_toolchains(
                 "//conditions:default": [],
             }),
             default_edition = edition,
-            extra_exec_rustc_flags = _rustc_flags_to_select(extra_exec_rustc_flags),
-            extra_rustc_flags = _rustc_flags_to_select(extra_rustc_flags),
+            extra_exec_rustc_flags = _default_rustc_flags(version) + _rustc_flags_to_select(extra_exec_rustc_flags),
+            extra_rustc_flags = _default_rustc_flags(version) + _rustc_flags_to_select(extra_rustc_flags),
             exec_triple = triple,
             target_triple = select(target_triple_select),
             visibility = ["//visibility:public"],

test/BUILD.bazel

@@ -14,6 +14,7 @@ load("@workspace_default_features//:data.bzl", workspace_default_features_dep_da
 load("@workspace_hyphen_dep_aliases//:defs.bzl", workspace_hyphen_dep_aliases_aliases = "aliases")
 load("@workspace_renamed_path_dep_aliases//:defs.bzl", workspace_renamed_path_dep_aliases_aliases = "aliases")
 load("//:rustdoc_musl_unwind_test.bzl", "rustdoc_musl_unwind_link_flags_test")
+load("//:self_contained_linker_test.bzl", "self_contained_linker_aarch64_test", "self_contained_linker_x86_64_test")
 load("//:target_triple_constraints_test.bzl", "target_triple_constraints_test")
 load("//:verify_aliases.bzl", "verify_alias", "verify_alias_absent", "verify_crate_feature_absent", "verify_crate_feature_present", "verify_dep_absent", "verify_dep_present", "verify_dev_dep_absent")
 load("//:workspace_lints_test.bzl", "inherited_workspace_lints_test", "opted_out_workspace_lints_test", "package_lints_test")
@@ -36,6 +37,23 @@ sh_test(
     }),
 )
 
+rust_binary(
+    name = "self_contained_linker_sample_bin",
+    srcs = ["main.rs"],
+    edition = "2021",
+    tags = ["manual"],
+)
+
+self_contained_linker_x86_64_test(
+    name = "self_contained_linker_x86_64_test",
+    target_under_test = ":self_contained_linker_sample_bin",
+)
+
+self_contained_linker_aarch64_test(
+    name = "self_contained_linker_aarch64_test",
+    target_under_test = ":self_contained_linker_sample_bin",
+)
+
 cc_library(
     name = "rustdoc_musl_unwind_cc",
     srcs = ["rustdoc_musl_unwind.cc"],

test/self_contained_linker_test.bzl

@@ -0,0 +1,51 @@
+"""Analysis test verifying that Linux x86_64 targets disable self-contained LLD via -Clinker-features=-lld."""
+
+load("@bazel_skylib//lib:unittest.bzl", "analysistest", "asserts")
+
+def _get_action_by_mnemonic(env, tut, mnemonic):
+    actions = [action for action in tut.actions if action.mnemonic == mnemonic]
+    asserts.equals(
+        env,
+        1,
+        len(actions),
+        "Expected exactly one {} action, got {}".format(mnemonic, [action.mnemonic for action in tut.actions]),
+    )
+    return actions[0]
+
+def _self_contained_linker_x86_64_test_impl(ctx):
+    env = analysistest.begin(ctx)
+    tut = analysistest.target_under_test(env)
+    action = _get_action_by_mnemonic(env, tut, "Rustc")
+
+    asserts.true(
+        env,
+        "-Clinker-features=-lld" in action.argv,
+        "Expected '-Clinker-features=-lld' in Rustc action argv for x86_64-unknown-linux-gnu, but it was missing: {}".format(action.argv),
+    )
+    return analysistest.end(env)
+
+def _self_contained_linker_aarch64_test_impl(ctx):
+    env = analysistest.begin(ctx)
+    tut = analysistest.target_under_test(env)
+    action = _get_action_by_mnemonic(env, tut, "Rustc")
+
+    asserts.false(
+        env,
+        "-Clinker-features=-lld" in action.argv,
+        "Did not expect '-Clinker-features=-lld' in Rustc action argv for aarch64-unknown-linux-gnu: {}".format(action.argv),
+    )
+    return analysistest.end(env)
+
+self_contained_linker_x86_64_test = analysistest.make(
+    _self_contained_linker_x86_64_test_impl,
+    config_settings = {
+        "//command_line_option:platforms": str(Label("@rules_rs//rs/platforms:x86_64-unknown-linux-gnu")),
+    },
+)
+
+self_contained_linker_aarch64_test = analysistest.make(
+    _self_contained_linker_aarch64_test_impl,
+    config_settings = {
+        "//command_line_option:platforms": str(Label("@rules_rs//rs/platforms:aarch64-unknown-linux-gnu")),
+    },
+)