Add opt-out from merging cc_lib object files in bindgen

bindgen/private/bindgen.bzl

@@ -78,6 +78,9 @@ def rust_bindgen_library(
     ):
         if shared in kwargs:
             bindgen_kwargs.update({shared: kwargs[shared]})
+    if "merge_cc_lib_objects_into_rlib" in kwargs:
+        bindgen_kwargs.update({"merge_cc_lib_objects_into_rlib": kwargs["merge_cc_lib_objects_into_rlib"]})
+        kwargs.pop("merge_cc_lib_objects_into_rlib")
 
     rust_bindgen(
         name = name + "__bindgen",
@@ -334,22 +337,28 @@ def _rust_bindgen_impl(ctx):
         toolchain = None,
     )
 
-    return [
-        _generate_cc_link_build_info(ctx, cc_lib),
-        # As in https://github.com/bazelbuild/rules_rust/pull/2361, we want
-        # to link cc_lib to the direct parent (rlib) using `-lstatic=<cc_lib>`
-        # rustc flag. Hence, we do not need to provide the whole CcInfo of
-        # cc_lib because it will cause the downstream binary to link the cc_lib
-        # again. The CcInfo here only contains the custom link flags (i.e.
-        # linkopts attribute) specified by users in cc_lib.
-        CcInfo(
-            linking_context = cc_common.create_linking_context(
-                linker_inputs = depset([cc_common.create_linker_input(
-                    owner = ctx.label,
-                    user_link_flags = _get_user_link_flags(cc_lib),
-                )]),
+    if ctx.attr.merge_cc_lib_objects_into_rlib:
+        providers = [
+            _generate_cc_link_build_info(ctx, cc_lib),
+            # As in https://github.com/bazelbuild/rules_rust/pull/2361, we want
+            # to link cc_lib to the direct parent (rlib) using `-lstatic=<cc_lib>`
+            # rustc flag. Hence, we do not need to provide the whole CcInfo of
+            # cc_lib because it will cause the downstream binary to link the cc_lib
+            # again. The CcInfo here only contains the custom link flags (i.e.
+            # linkopts attribute) specified by users in cc_lib.
+            CcInfo(
+                linking_context = cc_common.create_linking_context(
+                    linker_inputs = depset([cc_common.create_linker_input(
+                        owner = ctx.label,
+                        user_link_flags = _get_user_link_flags(cc_lib),
+                    )]),
+                ),
             ),
-        ),
+        ]
+    else:
+        providers = [cc_lib[CcInfo]]
+
+    return providers + [
         OutputGroupInfo(
             bindgen_bindings = depset([output]),
             bindgen_c_thunks = depset(([c_output] if wrap_static_fns else [])),
@@ -376,6 +385,11 @@ rust_bindgen = rule(
             allow_single_file = True,
             mandatory = True,
         ),
+        "merge_cc_lib_objects_into_rlib": attr.bool(
+            doc = ("When True, objects from `cc_lib` will be copied into the `rlib` archive produced by " +
+                   "the rust_library that depends on this `rust_bindgen` rule (using `BuildInfo` provider)"),
+            default = True,
+        ),
         "wrap_static_fns": attr.bool(
             doc = "Whether to create a separate .c file for static fns. Requires nightly toolchain, and a header that actually needs this feature (otherwise bindgen won't generate the file and Bazel complains).",
             default = False,

docs/src/flatten.md

@@ -328,7 +328,8 @@ is available under the key `dsym_folder` in `OutputGroupInfo`.
 ## rust_bindgen
 
 <pre>
-rust_bindgen(<a href="#rust_bindgen-name">name</a>, <a href="#rust_bindgen-bindgen_flags">bindgen_flags</a>, <a href="#rust_bindgen-cc_lib">cc_lib</a>, <a href="#rust_bindgen-clang_flags">clang_flags</a>, <a href="#rust_bindgen-header">header</a>, <a href="#rust_bindgen-wrap_static_fns">wrap_static_fns</a>)
+rust_bindgen(<a href="#rust_bindgen-name">name</a>, <a href="#rust_bindgen-bindgen_flags">bindgen_flags</a>, <a href="#rust_bindgen-cc_lib">cc_lib</a>, <a href="#rust_bindgen-clang_flags">clang_flags</a>, <a href="#rust_bindgen-header">header</a>, <a href="#rust_bindgen-merge_cc_lib_objects_into_rlib">merge_cc_lib_objects_into_rlib</a>,
+             <a href="#rust_bindgen-wrap_static_fns">wrap_static_fns</a>)
 </pre>
 
 Generates a rust source file from a cc_library and a header.
@@ -343,6 +344,7 @@ Generates a rust source file from a cc_library and a header.
 | <a id="rust_bindgen-cc_lib"></a>cc_lib |  The cc_library that contains the `.h` file. This is used to find the transitive includes.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |
 | <a id="rust_bindgen-clang_flags"></a>clang_flags |  Flags to pass directly to the clang executable.   | List of strings | optional |  `[]`  |
 | <a id="rust_bindgen-header"></a>header |  The `.h` file to generate bindings for.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |
+| <a id="rust_bindgen-merge_cc_lib_objects_into_rlib"></a>merge_cc_lib_objects_into_rlib |  When True, objects from `cc_lib` will be copied into the `rlib` archive produced by the rust_library that depends on this `rust_bindgen` rule (using `BuildInfo` provider)   | Boolean | optional |  `True`  |
 | <a id="rust_bindgen-wrap_static_fns"></a>wrap_static_fns |  Whether to create a separate .c file for static fns. Requires nightly toolchain, and a header that actually needs this feature (otherwise bindgen won't generate the file and Bazel complains).   | Boolean | optional |  `False`  |
 
 

docs/src/rust_bindgen.md

@@ -53,7 +53,8 @@ toolchains following the instructions for [rust_bindgen_toolchain](#rust_bindgen
 ## rust_bindgen
 
 <pre>
-rust_bindgen(<a href="#rust_bindgen-name">name</a>, <a href="#rust_bindgen-bindgen_flags">bindgen_flags</a>, <a href="#rust_bindgen-cc_lib">cc_lib</a>, <a href="#rust_bindgen-clang_flags">clang_flags</a>, <a href="#rust_bindgen-header">header</a>, <a href="#rust_bindgen-wrap_static_fns">wrap_static_fns</a>)
+rust_bindgen(<a href="#rust_bindgen-name">name</a>, <a href="#rust_bindgen-bindgen_flags">bindgen_flags</a>, <a href="#rust_bindgen-cc_lib">cc_lib</a>, <a href="#rust_bindgen-clang_flags">clang_flags</a>, <a href="#rust_bindgen-header">header</a>, <a href="#rust_bindgen-merge_cc_lib_objects_into_rlib">merge_cc_lib_objects_into_rlib</a>,
+             <a href="#rust_bindgen-wrap_static_fns">wrap_static_fns</a>)
 </pre>
 
 Generates a rust source file from a cc_library and a header.
@@ -68,6 +69,7 @@ Generates a rust source file from a cc_library and a header.
 | <a id="rust_bindgen-cc_lib"></a>cc_lib |  The cc_library that contains the `.h` file. This is used to find the transitive includes.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |
 | <a id="rust_bindgen-clang_flags"></a>clang_flags |  Flags to pass directly to the clang executable.   | List of strings | optional |  `[]`  |
 | <a id="rust_bindgen-header"></a>header |  The `.h` file to generate bindings for.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |
+| <a id="rust_bindgen-merge_cc_lib_objects_into_rlib"></a>merge_cc_lib_objects_into_rlib |  When True, objects from `cc_lib` will be copied into the `rlib` archive produced by the rust_library that depends on this `rust_bindgen` rule (using `BuildInfo` provider)   | Boolean | optional |  `True`  |
 | <a id="rust_bindgen-wrap_static_fns"></a>wrap_static_fns |  Whether to create a separate .c file for static fns. Requires nightly toolchain, and a header that actually needs this feature (otherwise bindgen won't generate the file and Bazel complains).   | Boolean | optional |  `False`  |
 
 

test/bindgen/bindgen_test.bzl

@@ -44,10 +44,60 @@ def _test_cc_linkopt(name):
         impl = _test_cc_linkopt_impl,
     )
 
+def _test_cc_lib_object_merging_impl(env, target):
+    env.expect.that_collection(target.actions).has_size(3)
+    env.expect.that_action(target.actions[0]).mnemonic().contains("RustBindgen")
+    env.expect.that_action(target.actions[1]).mnemonic().contains("FileWrite")
+    env.expect.that_action(target.actions[1]).content().contains("-lstatic=test_cc_lib_object_merging_cc")
+    env.expect.that_action(target.actions[2]).mnemonic().contains("FileWrite")
+    env.expect.that_action(target.actions[2]).content().contains("-Lnative=")
+
+def _test_cc_lib_object_merging_disabled_impl(env, target):
+    # no FileWrite actions writing arg files registered
+    env.expect.that_collection(target.actions).has_size(1)
+    env.expect.that_action(target.actions[0]).mnemonic().contains("RustBindgen")
+
+def _test_cc_lib_object_merging(name):
+    cc_library(name = name + "_cc", hdrs = ["simple.h"], srcs = ["simple.cc"])
+
+    rust_bindgen_library(
+        name = name + "_rust_bindgen",
+        cc_lib = name + "_cc",
+        header = "simple.h",
+        tags = ["manual"],
+        edition = "2021",
+    )
+
+    analysis_test(
+        name = name,
+        target = name + "_rust_bindgen__bindgen",
+        impl = _test_cc_lib_object_merging_impl,
+    )
+
+def _test_cc_lib_object_merging_disabled(name):
+    cc_library(name = name + "_cc", hdrs = ["simple.h"], srcs = ["simple.cc"])
+
+    rust_bindgen_library(
+        name = name + "_rust_bindgen",
+        cc_lib = name + "_cc",
+        header = "simple.h",
+        tags = ["manual"],
+        merge_cc_lib_objects_into_rlib = False,
+        edition = "2021",
+    )
+
+    analysis_test(
+        name = name,
+        target = name + "_rust_bindgen__bindgen",
+        impl = _test_cc_lib_object_merging_disabled_impl,
+    )
+
 def bindgen_test_suite(name):
     test_suite(
         name = name,
         tests = [
             _test_cc_linkopt,
+            _test_cc_lib_object_merging,
+            _test_cc_lib_object_merging_disabled,
         ],
     )