Add iOS toolchains, platforms, and constraint_values (#2090)

Refactored the description of target platforms. The source of truth is now the PLATFORMS table go/private/platforms.bzl. Declarations for config_settings in //go/platform; constraint_values and aliases in //go/toolchain; and toolchains in @go_sdk are generated from this table. In addition to the normal GOOS_GOARCH list, there are some additional entries for iOS. iOS platforms still have GOOS=darwin, but they are compatible with a different constraint_value (@bazel_tools//platforms:ios instead of @bazel_tools//platforms:osx). There are also separate platforms for pure mode, and cgo (with _cgo suffix). Cross compilation may still be done with (for example) --platforms=@io_bazel_rules_go//go/platforms:linux_amd64, and this no longer requires a configured C/C++ toolchain. To cross-compile with cgo, use --platforms=@io_bazel_rules_go//go/platforms:linux_amd64_cgo. A compatible configured C/C++ toolchain is required in that case. Fixes #2079
bazel-contrib · Jun 13, 2019 · f2373c9 · f2373c9
1 parent 20ab486
commit f2373c9
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Showing 20 changed files with 583 additions and 274 deletions.
diff --git a/BUILD.bazel b/BUILD.bazel
@@ -2,7 +2,7 @@ load("@io_bazel_rules_go//go:def.bzl", "go_path")
 load("@io_bazel_rules_go//go/private:tools/lines_sorted_test.bzl", "lines_sorted_test")
 load("@io_bazel_rules_go//go/private:rules/nogo.bzl", "nogo")
 load("@io_bazel_rules_go//go/private:rules/info.bzl", "go_info")
-load("@io_bazel_rules_go//go/private:context.bzl", "go_context_data")
+load("@io_bazel_rules_go//go/private:context.bzl", "cgo_context_data", "go_context_data")
 load("@io_bazel_rules_go//go/private:rules/stdlib.bzl", "stdlib")
 
 stdlib(
@@ -59,6 +59,8 @@ nogo(
     ],
 )
 
+# go_context_data collects build options and is depended on by all Go targets.
+# It may depend on cgo_context_data via go_toolchain.
 go_context_data(
     name = "go_context_data",
     strip = select({
@@ -69,6 +71,13 @@ go_context_data(
     visibility = ["//visibility:public"],
 )
 
+# cgo_context_data collects information about the C/C++ toolchain.
+# go_toolchains may depend on this in order to support cgo.
+cgo_context_data(
+    name = "cgo_context_data",
+    visibility = ["//visibility:public"],
+)
+
 lines_sorted_test(
     name = "contributors_sorted_test",
     size = "small",

diff --git a/go/platform/list.bzl b/go/platform/list.bzl
@@ -12,113 +12,54 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-GOOS = {
-    "android": None,
-    "darwin": "@bazel_tools//platforms:osx",
-    "dragonfly": None,
-    "freebsd": "@bazel_tools//platforms:freebsd",
-    "linux": "@bazel_tools//platforms:linux",
-    "nacl": None,
-    "netbsd": None,
-    "openbsd": None,
-    "plan9": None,
-    "solaris": None,
-    "windows": "@bazel_tools//platforms:windows",
-    "js": None,
-}
-
-GOARCH = {
-    "386": "@bazel_tools//platforms:x86_32",
-    "amd64": "@bazel_tools//platforms:x86_64",
-    "amd64p32": None,
-    "arm": "@bazel_tools//platforms:arm",
-    "arm64": "@bazel_tools//platforms:aarch64",
-    "mips": None,
-    "mips64": None,
-    "mips64le": None,
-    "mipsle": None,
-    "ppc64": None,
-    "ppc64le": "@bazel_tools//platforms:ppc",
-    "s390x": "@bazel_tools//platforms:s390x",
-    "wasm": None,
-}
-
-GOOS_GOARCH = (
-    ("android", "386"),
-    ("android", "amd64"),
-    ("android", "arm"),
-    ("android", "arm64"),
-    ("darwin", "386"),
-    ("darwin", "amd64"),
-    ("darwin", "arm"),
-    ("darwin", "arm64"),
-    ("dragonfly", "amd64"),
-    ("freebsd", "386"),
-    ("freebsd", "amd64"),
-    ("freebsd", "arm"),
-    ("linux", "386"),
-    ("linux", "amd64"),
-    ("linux", "arm"),
-    ("linux", "arm64"),
-    ("linux", "mips"),
-    ("linux", "mips64"),
-    ("linux", "mips64le"),
-    ("linux", "mipsle"),
-    ("linux", "ppc64"),
-    ("linux", "ppc64le"),
-    ("linux", "s390x"),
-    ("nacl", "386"),
-    ("nacl", "amd64p32"),
-    ("nacl", "arm"),
-    ("netbsd", "386"),
-    ("netbsd", "amd64"),
-    ("netbsd", "arm"),
-    ("openbsd", "386"),
-    ("openbsd", "amd64"),
-    ("openbsd", "arm"),
-    ("plan9", "386"),
-    ("plan9", "amd64"),
-    ("plan9", "arm"),
-    ("solaris", "amd64"),
-    ("windows", "386"),
-    ("windows", "amd64"),
-    ("js", "wasm"),
+load(
+    "@io_bazel_rules_go//go/private:platforms.bzl",
+    "PLATFORMS",
+    _GOARCH = "GOARCH_CONSTRAINTS",
+    _GOOS = "GOOS_CONSTRAINTS",
+    _GOOS_GOARCH = "GOOS_GOARCH",
+    _MSAN_GOOS_GOARCH = "MSAN_GOOS_GOARCH",
+    _RACE_GOOS_GOARCH = "RACE_GOOS_GOARCH",
 )
 
-RACE_GOOS_GOARCH = (
-    ("darwin", "amd64"),
-    ("freebsd", "amd64"),
-    ("linux", "amd64"),
-    ("windows", "amd64"),
-)
+GOOS_GOARCH = _GOOS_GOARCH
+GOOS = _GOOS
+GOARCH = _GOARCH
+RACE_GOOS_GOARCH = _RACE_GOOS_GOARCH
+MSAN_GOOS_GOARCH = _MSAN_GOOS_GOARCH
 
-MSAN_GOOS_GOARCH = (
-    ("linux", "amd64"),
-)
+def _os_constraint(goos):
+    if goos == "darwin":
+        return "@io_bazel_rules_go//go/toolchain:is_darwin"
+    else:
+        return "@io_bazel_rules_go//go/toolchain:" + goos
+
+def _arch_constraint(goarch):
+    return "@io_bazel_rules_go//go/toolchain:" + goarch
 
 def declare_config_settings():
+    """Generates config_setting targets for each goos, goarch, and valid
+    goos_goarch pair. These targets may be used in select expressions.
+    Each target refers to a corresponding constraint_value in //go/toolchain.
+
+    Note that the "darwin" targets are true when building for either
+    macOS or iOS.
+    """
     for goos in GOOS:
         native.config_setting(
             name = goos,
-            constraint_values = ["//go/toolchain:" + goos],
+            constraint_values = [_os_constraint(goos)],
         )
     for goarch in GOARCH:
         native.config_setting(
             name = goarch,
-            constraint_values = ["//go/toolchain:" + goarch],
+            constraint_values = [_arch_constraint(goarch)],
         )
     for goos, goarch in GOOS_GOARCH:
         native.config_setting(
             name = goos + "_" + goarch,
             constraint_values = [
-                "//go/toolchain:" + goos,
-                "//go/toolchain:" + goarch,
+                _os_constraint(goos),
+                _arch_constraint(goarch),
             ],
         )
-
-def generate_toolchain_names():
-    # Keep in sync with generate_toolchains
-    return [
-        "go_{}_{}".format(target_goos, target_goarch)
-        for target_goos, target_goarch in GOOS_GOARCH
-    ]
diff --git a/go/private/actions/archive.bzl b/go/private/actions/archive.bzl
@@ -82,9 +82,7 @@ def emit_archive(go, source = None):
         cxxopts = [f for fs in source.cxxopts for f in fs.split(" ")]
         clinkopts = [f for fs in source.clinkopts for f in fs.split(" ")]
 
-        cgo_inputs = depset()
-        cgo_deps = depset()
-        if source.cgo:
+        if source.cgo and not go.mode.pure:
             cgo = cgo_configure(
                 go,
                 srcs = split.go + split.c + split.asm + split.cxx + split.headers,
@@ -94,33 +92,43 @@ def emit_archive(go, source = None):
                 cxxopts = cxxopts,
                 clinkopts = clinkopts,
             )
-            runfiles = runfiles.merge(cgo.runfiles)
-            cgo_inputs = cgo.inputs
             cgo_deps = cgo.deps
-            cppopts = cgo.cppopts
-            copts = cgo.copts
-            cxxopts = cgo.cxxopts
-            clinkopts = cgo.clinkopts
-
-        emit_compilepkg(
-            go,
-            sources = split.go + split.c + split.asm + split.cxx + split.headers,
-            cover = source.cover,
-            importpath = effective_importpath_pkgpath(source.library)[0],
-            importmap = source.library.importmap,
-            archives = direct,
-            out_lib = out_lib,
-            out_export = out_export,
-            gc_goopts = source.gc_goopts,
-            cgo = source.cgo,
-            cgo_inputs = cgo_inputs,
-            cppopts = cppopts,
-            copts = copts,
-            cxxopts = cxxopts,
-            clinkopts = clinkopts,
-            cgo_archives = source.cgo_archives,
-            testfilter = testfilter,
-        )
+            runfiles = runfiles.merge(cgo.runfiles)
+            emit_compilepkg(
+                go,
+                sources = split.go + split.c + split.asm + split.cxx + split.headers,
+                cover = source.cover,
+                importpath = effective_importpath_pkgpath(source.library)[0],
+                importmap = source.library.importmap,
+                archives = direct,
+                out_lib = out_lib,
+                out_export = out_export,
+                gc_goopts = source.gc_goopts,
+                cgo = True,
+                cgo_inputs = cgo.inputs,
+                cppopts = cgo.cppopts,
+                copts = cgo.copts,
+                cxxopts = cgo.cxxopts,
+                clinkopts = cgo.clinkopts,
+                cgo_archives = source.cgo_archives,
+                testfilter = testfilter,
+            )
+        else:
+            cgo_deps = depset()
+            emit_compilepkg(
+                go,
+                sources = split.go + split.c + split.asm + split.cxx + split.headers,
+                cover = source.cover,
+                importpath = effective_importpath_pkgpath(source.library)[0],
+                importmap = source.library.importmap,
+                archives = direct,
+                out_lib = out_lib,
+                out_export = out_export,
+                gc_goopts = source.gc_goopts,
+                cgo = False,
+                cgo_archives = source.cgo_archives,
+                testfilter = testfilter,
+            )
     else:
         cgo_deps = source.cgo_deps
 

diff --git a/go/private/actions/stdlib.bzl b/go/private/actions/stdlib.bzl
@@ -66,11 +66,15 @@ def _build_stdlib(go):
     args.add_all(link_mode_args(go.mode))
     go.actions.write(root_file, "")
     env = go.env
-    env.update({
-        "CC": go.cgo_tools.c_compiler_path,
-        "CGO_CFLAGS": " ".join(go.cgo_tools.c_compile_options),
-        "CGO_LDFLAGS": " ".join(extldflags_from_cc_toolchain(go)),
-    })
+    if go.mode.pure:
+        env.update({"CGO_ENABLED": "0"})
+    else:
+        env.update({
+            "CGO_ENABLED": "1",
+            "CC": go.cgo_tools.c_compiler_path,
+            "CGO_CFLAGS": " ".join(go.cgo_tools.c_compile_options),
+            "CGO_LDFLAGS": " ".join(extldflags_from_cc_toolchain(go)),
+        })
     inputs = (go.sdk.srcs +
               go.sdk.headers +
               go.sdk.tools +
@@ -89,4 +93,3 @@ def _build_stdlib(go):
         root_file = root_file,
         libs = [pkg],
     )
-
diff --git a/go/private/compat/compat_repo.bzl b/go/private/compat/compat_repo.bzl
@@ -27,6 +27,13 @@
 load("@io_bazel_rules_go//go/private:skylib/lib/versions.bzl", "versions")
 
 def _go_rules_compat_impl(ctx):
+    darwin_tpl_path = ctx.path(Label("@io_bazel_rules_go//go/private:compat/darwin.bzl.tpl"))
+    if "mac" in ctx.os.name:
+        default_darwin_constraint_value = "@io_bazel_rules_go//go/toolchain:is_darwin"
+    else:
+        default_darwin_constraint_value = "@io_bazel_rules_go//go/toolchain:not_darwin"
+    ctx.template("darwin.bzl", darwin_tpl_path, {"{default_darwin_constraint_value}": default_darwin_constraint_value})
+
     ctx.file("BUILD.bazel")
     ctx.symlink(ctx.attr.impl, "compat.bzl")
 

diff --git a/go/private/compat/darwin.bzl.tpl b/go/private/compat/darwin.bzl.tpl
@@ -0,0 +1,15 @@
+# Copyright 2019 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+DEFAULT_DARWIN_CONSTRAINT_VALUE = "{default_darwin_constraint_value}"