Link in native libraries of transitive dependencies in archive mode

go/private/common.bzl

@@ -241,6 +241,12 @@ def as_set(v):
         return depset(v)
     fail("as_tuple failed on {}".format(v))
 
+_STRUCT_TYPE = type(struct())
+
+def is_struct(v):
+    """Returns true if v is a struct."""
+    return type(v) == _STRUCT_TYPE
+
 def count_group_matches(v, prefix, suffix):
     """Counts reluctant substring matches between prefix and suffix.
 

go/private/context.bzl

@@ -50,6 +50,7 @@ load(
     "as_iterable",
     "goos_to_extension",
     "goos_to_shared_extension",
+    "is_struct",
 )
 load(
     "//go/platform:apple.bzl",
@@ -240,6 +241,7 @@ def _library_to_source(go, attr, library, coverage_instrumented):
         "clinkopts": _expand_opts(go, "clinkopts", getattr(attr, "clinkopts", [])),
         "cgo_deps": [],
         "cgo_exports": [],
+        "cc_info": None,
     }
     if coverage_instrumented:
         source["cover"] = attr_srcs
@@ -266,6 +268,7 @@ def _library_to_source(go, attr, library, coverage_instrumented):
                 fail("source {} has C/C++ extension, but cgo was not enabled (set 'cgo = True')".format(f.path))
     if library.resolve:
         library.resolve(go, attr, source, _merge_embed)
+    source["cc_info"] = _collect_cc_infos(source["deps"], source["cdeps"])
     return GoSource(**source)
 
 def _collect_runfiles(go, data, deps):
@@ -280,6 +283,19 @@ def _collect_runfiles(go, data, deps):
         runfiles = runfiles.merge(get_source(t).runfiles)
     return runfiles
 
+def _collect_cc_infos(deps, cdeps):
+    cc_infos = []
+    for dep in cdeps:
+        if CcInfo in dep:
+            cc_infos.append(dep[CcInfo])
+    for dep in deps:
+        # dep may be a struct, which doesn't support indexing by providers.
+        if is_struct(dep):
+            continue
+        if GoSource in dep:
+            cc_infos.append(dep[GoSource].cc_info)
+    return cc_common.merge_cc_infos(cc_infos = cc_infos)
+
 def _check_binary_dep(go, dep, edge):
     """Checks that this rule doesn't depend on a go_binary or go_test.
 

go/private/rules/binary.bzl

@@ -163,7 +163,7 @@ def _go_binary_impl(ctx):
             cc_import_kwargs["alwayslink"] = True
         ccinfo = new_cc_import(go, **cc_import_kwargs)
         ccinfo = cc_common.merge_cc_infos(
-            cc_infos = [ccinfo] + [d[CcInfo] for d in source.cdeps],
+            cc_infos = [ccinfo, source.cc_info],
         )
         providers.append(ccinfo)
 

go/providers.rst

@@ -204,6 +204,10 @@ method. In general, only rules_go should need to build or handle these.
 +--------------------------------+-----------------------------------------------------------------+
 | The exposed cc headers for these sources.                                                        |
 +--------------------------------+-----------------------------------------------------------------+
+| :param:`cc_info`               | :type:`CcInfo`                                                  |
++--------------------------------+-----------------------------------------------------------------+
+| The result of merging the ``CcInfo``s of all `deps` and `cdeps`                                  |
++--------------------------------+-----------------------------------------------------------------+
 
 GoArchiveData
 ~~~~~~~~~~~~~

tests/core/cgo/BUILD.bazel

@@ -434,3 +434,41 @@ go_binary(
     }),
     deps = [":use_external_symbol"],
 )
+
+cc_library(
+    name = "native_dep",
+    srcs = ["native_dep.c"],
+    hdrs = ["native_dep.h"],
+    # Force static linking to ensure that the build doesn't succeed by
+    # accidentally picking up the shared library in the search path.
+    linkstatic = True,
+)
+
+go_library(
+    name = "transitive_dep",
+    srcs = ["transitive_dep.go"],
+    cdeps = [":native_dep"],
+    cgo = True,
+    importpath = "github.com/bazelbuild/rules_go/tests/core/cgo/transitive_dep",
+)
+
+go_library(
+    name = "direct_dep",
+    srcs = ["direct_dep.go"],
+    importpath = "github.com/bazelbuild/rules_go/tests/core/cgo/direct_dep",
+    deps = [":transitive_dep"],
+)
+
+go_binary(
+    name = "use_transitive_symbol",
+    srcs = ["use_transitive_symbol.go"],
+    cgo = True,
+    linkmode = "c-archive",
+    deps = [":direct_dep"],
+)
+
+cc_binary(
+    name = "use_c_symbol_through_go",
+    srcs = ["use_c_symbol_through_go.c"],
+    deps = [":use_transitive_symbol"],
+)

tests/core/cgo/direct_dep.go

@@ -0,0 +1,9 @@
+package direct_dep
+
+import (
+	"github.com/bazelbuild/rules_go/tests/core/cgo/transitive_dep"
+)
+
+func PrintGreeting() {
+	transitive_dep.PrintGreeting()
+}

tests/core/cgo/native_dep.c

@@ -0,0 +1,5 @@
+#include <stdio.h>
+
+void native_greeting(void) {
+    printf("Hello, world!\n");
+}

tests/core/cgo/native_dep.h

@@ -0,0 +1 @@
+extern void native_greeting(void);

tests/core/cgo/transitive_dep.go

@@ -0,0 +1,10 @@
+package transitive_dep
+
+/*
+#include "tests/core/cgo/native_dep.h"
+ */
+import "C"
+
+func PrintGreeting() {
+	C.native_greeting();
+}

tests/core/cgo/use_c_symbol_through_go.c

@@ -0,0 +1,5 @@
+#include "tests/core/cgo/use_transitive_symbol.h"
+
+int main() {
+    PrintGreeting();
+}

tests/core/cgo/use_transitive_symbol.go

@@ -0,0 +1,14 @@
+package main
+
+import "C"
+
+import (
+	"github.com/bazelbuild/rules_go/tests/core/cgo/direct_dep"
+)
+
+//export PrintGreeting
+func PrintGreeting() {
+	direct_dep.PrintGreeting()
+}
+
+func main() {}