Split C and C++ compilation

go/private/actions/archive.bzl

@@ -54,7 +54,7 @@ def emit_archive(go, source=None):
     runfiles = runfiles.merge(a.runfiles)
     if a.source.mode != go.mode: fail("Archive mode does not match {} is {} expected {}".format(a.data.label, mode_string(a.source.mode), mode_string(go.mode)))
 
-  if len(extra_objects) == 0 and source.cgo_archive == None:
+  if len(extra_objects) == 0 and not source.cgo_archives:
     go.compile(go,
         sources = split.go,
         importpath = source.library.importmap,
@@ -77,7 +77,7 @@ def emit_archive(go, source=None):
         in_lib = partial_lib,
         out_lib = out_lib,
         objects = extra_objects,
-        archive = source.cgo_archive,
+        archives = source.cgo_archives,
     )
   data = GoArchiveData(
       name = source.library.name,

go/private/actions/pack.bzl

@@ -16,7 +16,7 @@ def emit_pack(go,
     in_lib = None,
     out_lib = None,
     objects = [],
-    archive = None):
+    archives = []):
   """See go/toolchains.rst#pack for full documentation."""
 
   if in_lib == None: fail("in_lib is a required parameter")
@@ -32,9 +32,8 @@ def emit_pack(go,
   inputs.extend(objects)
   arguments.add(objects, before_each="-obj")
 
-  if archive:
-    inputs.append(archive)
-    arguments.add(["-arc", archive])
+  inputs.extend(archives)
+  arguments.add(archives, before_each="-arc")
 
   go.actions.run(
       inputs = inputs,

go/private/common.bzl

@@ -41,6 +41,10 @@ hdr_exts = [
 
 c_exts = [
     ".c",
+    ".h",
+]
+
+cxx_exts = [
     ".cc",
     ".cxx",
     ".cpp",
@@ -56,7 +60,7 @@ cc_hdr_filetype = FileType(hdr_exts)
 
 # Extensions of files we can build with the Go compiler or with cc_library.
 # This is a subset of the extensions recognized by go/build.
-cgo_filetype = FileType(go_exts + asm_exts + c_exts)
+cgo_filetype = FileType(go_exts + asm_exts + c_exts + cxx_exts)
 
 def pkg_dir(workspace_root, package_name):
   """Returns a relative path to a package directory from the root of the
@@ -75,12 +79,14 @@ def split_srcs(srcs):
     asm = [],
     headers = [],
     c = [],
+    cxx = [],
   )
   ext_pairs = (
     (sources.go, go_exts),
     (sources.headers, hdr_exts),
     (sources.asm, asm_exts),
     (sources.c, c_exts),
+    (sources.cxx, cxx_exts),
   )
   extmap = {}
   for outs, exts in ext_pairs:
@@ -97,7 +103,7 @@ def split_srcs(srcs):
   return sources
 
 def join_srcs(source):
-  return source.go + source.headers + source.asm + source.c
+  return source.go + source.headers + source.asm + source.c + source.cxx
 
 def env_execute(ctx, arguments, environment = {}, **kwargs):
   """env_executes a command in a repository context. It prepends "env -i"

go/private/context.bzl

@@ -97,6 +97,8 @@ def _new_args(go):
       "-compiler_path", go.cgo_tools.compiler_path,
       "-cc", go.cgo_tools.compiler_executable,
     ])
+    args.add(go.cgo_tools.compiler_options, before_each = "-c_flag")
+    args.add(go.cgo_tools.compiler_options, before_each = "-cxx_flag")
     args.add(go.cgo_tools.compiler_options, before_each = "-cpp_flag")
     args.add(go.cgo_tools.linker_options, before_each = "-ld_flag")
   return args
@@ -129,10 +131,10 @@ def _merge_embed(source, embed):
   source["runfiles"] = source["runfiles"].merge(s.runfiles)
   source["cgo_deps"] = source["cgo_deps"] + s.cgo_deps
   source["cgo_exports"] = source["cgo_exports"] + s.cgo_exports
-  if s.cgo_archive:
-    if source["cgo_archive"]:
-      fail("multiple libraries with cgo_archive embedded")
-    source["cgo_archive"] = s.cgo_archive
+  if s.cgo_archives:
+    if source["cgo_archives"]:
+      fail("multiple libraries with cgo_archives embedded")
+    source["cgo_archives"] = s.cgo_archives
 
 def _library_to_source(go, attr, library, coverage_instrumented):
   #TODO: stop collapsing a depset in this line...
@@ -149,7 +151,7 @@ def _library_to_source(go, attr, library, coverage_instrumented):
       "deps" : getattr(attr, "deps", []),
       "gc_goopts" : getattr(attr, "gc_goopts", []),
       "runfiles" : go._ctx.runfiles(collect_data = True),
-      "cgo_archive" : None,
+      "cgo_archives" : [],
       "cgo_deps" : [],
       "cgo_exports" : [],
   }

go/private/rules/cgo.bzl

@@ -78,20 +78,23 @@ def _c_filter_options(options, blacklist):
   return [opt for opt in options
         if not any([opt.startswith(prefix) for prefix in blacklist])]
 
-def _select_archive(files):
+def _select_archives(files):
   """Selects a single archive from a list of files produced by a
   static cc_library.
 
   In some configurations, cc_library can produce multiple files, and the
   order isn't guaranteed, so we can't simply pick the first one.
   """
   # list of file extensions in descending order or preference.
+  outs = []
   exts = [".pic.lo", ".lo", ".a"]
   for ext in exts:
     for f in files:
       if f.basename.endswith(ext):
-        return f
-  fail("cc_library did not produce any files")
+        outs.append(f)
+  if not outs:
+    fail("cc_library did not produce any files")
+  return outs
 
 def _cgo_codegen_impl(ctx):
   go = go_context(ctx)
@@ -111,6 +114,7 @@ def _cgo_codegen_impl(ctx):
   args.add(["-cc", str(cc), "-objdir", out_dir])
 
   c_outs = [cgo_export_h, cgo_export_c]
+  cxx_outs = [cgo_export_h]
   transformed_go_outs = []
   gen_go_outs = [cgo_types]
 
@@ -135,6 +139,11 @@ def _cgo_codegen_impl(ctx):
     gen_file = go.declare_file(go, path=mangled_stem + ".cgo1."+src_ext)
     c_outs.append(gen_file)
     args.add(["-src", gen_file.path + "=" + src.path])
+  for src in source.cxx:
+    mangled_stem, src_ext = _mangle(src, stems)
+    gen_file = go.declare_file(go, path=mangled_stem + ".cgo1."+src_ext)
+    cxx_outs.append(gen_file)
+    args.add(["-src", gen_file.path + "=" + src.path])
 
   inputs = sets.union(ctx.files.srcs, go.crosstool, go.stdlib.files,
                       *[d.cc.transitive_headers for d in ctx.attr.deps])
@@ -164,7 +173,7 @@ def _cgo_codegen_impl(ctx):
   args.add(copts)
   ctx.actions.run(
       inputs = inputs + go.crosstool,
-      outputs = c_outs + gen_go_outs + transformed_go_outs + [cgo_main],
+      outputs = c_outs + cxx_outs + gen_go_outs + transformed_go_outs + [cgo_main],
       mnemonic = "CGoCodeGen",
       progress_message = "CGoCodeGen %s" % ctx.label,
       executable = go.builders.cgo,
@@ -185,6 +194,7 @@ def _cgo_codegen_impl(ctx):
       ),
       OutputGroupInfo(
           c_files = sets.union(c_outs, source.headers),
+          cxx_files = sets.union(cxx_outs, source.headers),
           go_files = sets.union(transformed_go_outs, gen_go_outs),
           main_c = as_set([cgo_main]),
       ),
@@ -199,6 +209,8 @@ _cgo_codegen = go_rule(
             providers = ["cc"],
         ),
         "copts": attr.string_list(),
+        "cxxopts": attr.string_list(),
+        "cppopts": attr.string_list(),
         "linkopts": attr.string_list(),
     },
 )
@@ -254,7 +266,7 @@ def _not_pure(ctx, mode):
 def _cgo_resolve_source(go, attr, source, merge):
   library = source["library"]
   cgo_info = library.cgo_info
-  
+
   source["orig_srcs"] = cgo_info.orig_srcs
   source["runfiles"] = cgo_info.runfiles
   if source["mode"].pure:
@@ -266,7 +278,7 @@ def _cgo_resolve_source(go, attr, source, merge):
     source["cover"] = cgo_info.transformed_go_srcs
     source["cgo_deps"] = cgo_info.cgo_deps
     source["cgo_exports"] = cgo_info.cgo_exports
-    source["cgo_archive"] = cgo_info.cgo_archive
+    source["cgo_archives"] = cgo_info.cgo_archives
 
 def _cgo_collect_info_impl(ctx):
   go = go_context(ctx)
@@ -283,7 +295,7 @@ def _cgo_collect_info_impl(ctx):
           gen_go_srcs = codegen.gen_go + import_files,
           cgo_deps = codegen.deps,
           cgo_exports = codegen.exports,
-          cgo_archive = _select_archive(ctx.files.lib),
+          cgo_archives = _select_archives(ctx.files.libs),
           runfiles = runfiles,
       ),
   )
@@ -305,7 +317,7 @@ _cgo_collect_info = go_rule(
             mandatory = True,
             providers = [_CgoCodegen],
         ),
-        "lib": attr.label(
+        "libs": attr.label_list(
             mandatory = True,
             providers = ["cc"],
         ),
@@ -315,7 +327,7 @@ _cgo_collect_info = go_rule(
 """No-op rule that collects information from _cgo_codegen and cc_library
 info into a GoSourceList provider for easy consumption."""
 
-def setup_cgo_library(name, srcs, cdeps, copts, clinkopts):
+def setup_cgo_library(name, srcs, cdeps, copts, cxxopts, cppopts, clinkopts):
   # Apply build constraints to source files (both Go and C) but not to header
   # files. Separate filtered Go and C sources.
 
@@ -325,13 +337,17 @@ def setup_cgo_library(name, srcs, cdeps, copts, clinkopts):
       "external/" + REPOSITORY_NAME[1:] if len(REPOSITORY_NAME) > 1 else "",
       PACKAGE_NAME)
   copts = copts + ["-I", base_dir]
+  cxxopts = cxxopts + ["-I", base_dir]
+  cppopts = cppopts + ["-I", base_dir]
 
   cgo_codegen_name = name + ".cgo_codegen"
   _cgo_codegen(
       name = cgo_codegen_name,
       srcs = srcs,
       deps = cdeps,
       copts = copts,
+      cxxopts = cxxopts,
+      cppopts = cppopts,
       linkopts = clinkopts,
       visibility = ["//visibility:private"],
   )
@@ -352,6 +368,14 @@ def setup_cgo_library(name, srcs, cdeps, copts, clinkopts):
       visibility = ["//visibility:private"],
   )
 
+  select_cxx_files = name + ".select_cxx_files"
+  native.filegroup(
+      name = select_cxx_files,
+      srcs = [cgo_codegen_name],
+      output_group = "cxx_files",
+      visibility = ["//visibility:private"],
+  )
+
   select_main_c = name + ".select_main_c"
   native.filegroup(
       name = select_main_c,
@@ -366,9 +390,9 @@ def setup_cgo_library(name, srcs, cdeps, copts, clinkopts):
   platform_copts = _DEFAULT_PLATFORM_COPTS
   platform_linkopts = platform_copts
 
-  cgo_lib_name = name + ".cgo_c_lib"
+  cgo_c_lib_name = name + ".cgo_c_lib"
   native.cc_library(
-      name = cgo_lib_name,
+      name = cgo_c_lib_name,
       srcs = [select_c_files],
       deps = cdeps,
       copts = copts + platform_copts + [
@@ -382,13 +406,33 @@ def setup_cgo_library(name, srcs, cdeps, copts, clinkopts):
       visibility = ["//visibility:private"],
   )
 
+  cgo_cxx_lib_name = name + ".cgo_cxx_lib"
+  native.cc_library(
+      name = cgo_cxx_lib_name,
+      srcs = [select_cxx_files],
+      deps = cdeps,
+      copts = cxxopts + platform_copts + [
+          # The generated thunks often contain unused variables.
+          "-Wno-unused-variable",
+      ],
+      linkopts = clinkopts + platform_linkopts,
+      linkstatic = 1,
+      # _cgo_.o needs all symbols because _cgo_import needs to see them.
+      alwayslink = 1,
+      visibility = ["//visibility:private"],
+  )
+  cgo_libs = [
+      cgo_c_lib_name,
+      cgo_cxx_lib_name,
+  ]
+
   # Create a loadable object with no undefined references. cgo reads this
   # when it generates _cgo_import.go.
   cgo_o_name = name + "._cgo_.o"
   native.cc_binary(
       name = cgo_o_name,
       srcs = [select_main_c],
-      deps = cdeps + [cgo_lib_name],
+      deps = cdeps + cgo_libs,
       copts = copts,
       linkopts = clinkopts,
       visibility = ["//visibility:private"],
@@ -408,7 +452,7 @@ def setup_cgo_library(name, srcs, cdeps, copts, clinkopts):
       name = cgo_embed_name,
       srcs = srcs,
       codegen = cgo_codegen_name,
-      lib = cgo_lib_name,
+      libs = cgo_libs,
       cgo_import = cgo_import_name,
       visibility = ["//visibility:private"],
   )

go/private/rules/wrappers.bzl

@@ -25,6 +25,8 @@ _CGO_ATTRS = {
     "srcs": None,
     "cdeps": [],
     "copts": [],
+    "cxxopts": [],
+    "cppopts": [],
     "clinkopts": [],
 }
 

go/tools/builders/env.go

@@ -47,6 +47,8 @@ type GoEnv struct {
 	goarch       string
 	tags         string
 	cc           string
+	c_flags      multiFlag
+	cxx_flags    multiFlag
 	cpp_flags    multiFlag
 	ld_flags     multiFlag
 	shared       bool
@@ -104,7 +106,9 @@ func envFlags(flags *flag.FlagSet) *GoEnv {
 	flags.StringVar(&env.tags, "tags", "", "Only pass through files that match these tags.")
 	flags.BoolVar(&env.shared, "shared", false, "Build in shared mode")
 	flags.StringVar(&env.cc, "cc", "", "Sets the c compiler to use")
-	flags.Var(&env.cpp_flags, "cpp_flag", "An entry to add to the c compiler flags")
+	flags.Var(&env.c_flags, "c_flag", "An entry to add to the C compiler flags")
+	flags.Var(&env.cxx_flags, "cxx_flag", "An entry to add to the C++ compiler flags")
+	flags.Var(&env.cpp_flags, "cpp_flag", "An entry to add to the CPP compiler flags")
 	flags.Var(&env.ld_flags, "ld_flag", "An entry to add to the c linker flags")
 	return env
 }
@@ -150,18 +154,15 @@ func (env *GoEnv) env() []string {
 			fmt.Sprintf("CXX=%s", cc),
 		)
 	}
-	if len(env.cpp_flags) > 0 {
-		v := strings.Join(env.cpp_flags, " ")
-		result = append(result,
-			fmt.Sprintf("CGO_CFLAGS=%s", v),
-			fmt.Sprintf("CGO_CPPFLAGS=%s", v),
-			fmt.Sprintf("CGO_CXXFLAGS=%s", v),
-		)
+	cgoFlags := map[string]multiFlag{
+		"CGO_CFLAGS":   env.c_flags,
+		"CGO_CXXFLAGS": env.cxx_flags,
+		"CGO_CPPFLAGS": env.cpp_flags,
+		"CGO_LDFLAGS":  env.ld_flags,
 	}
-	if len(env.ld_flags) > 0 {
-		result = append(result,
-			fmt.Sprintf("CGO_LDFLAGS=%s", strings.Join(env.ld_flags, " ")),
-		)
+	for envVar, flags := range cgoFlags {
+		v := strings.Join(flags, " ")
+		result = append(result, envVar+"="+v)
 	}
 	return result
 }