Build stdlib from inside the aspect (#1295)

* Build stdlib from inside the aspect

This removes the hard coded list of standard libraries, and builds it per aspect
being propagated.
This is both cleaner and a pre-requisite for the additional link modes to work.

Related to #1264 and #54 and #539

* review feedback

BUILD.bazel

@@ -3,15 +3,10 @@ load("@io_bazel_rules_go//go/private:tools/lines_sorted_test.bzl", "lines_sorted
 load("@io_bazel_rules_go//go/private:rules/info.bzl", "go_info")
 load("@io_bazel_rules_go//proto:go_proto_library.bzl", "go_google_protobuf")
 load("@io_bazel_rules_go//go/private:context.bzl", "go_context_data")
+load("@io_bazel_rules_go//go/private:rules/stdlib.bzl", "stdlib")
 
-go_context_data(
-    name = "go_bootstrap_context_data",
-    strip = select({
-        "@io_bazel_rules_go//go/private:strip-always": "always",
-        "@io_bazel_rules_go//go/private:strip-sometimes": "sometimes",
-        "@io_bazel_rules_go//go/private:strip-never": "never",
-    }),
-    stdlib_all = [],
+stdlib(
+    name = "stdlib",
     visibility = ["//visibility:public"],
 )
 

go/private/BUILD.sdk.bazel

@@ -1,5 +1,3 @@
-load("@io_bazel_rules_go//go/private:rules/stdlib.bzl", "stdlib")
-
 package(default_visibility = [ "//visibility:public" ])
 
 filegroup(

go/private/context.bzl

@@ -45,14 +45,20 @@ INFERRED_PATH = "inferred"
 
 EXPORT_PATH = "export"
 
-def _declare_file(go, path="", ext="", name = ""):
-  filename = mode_string(go.mode) + "/"
-  filename += name if name else go._ctx.label.name
+def _child_name(go, path, ext, name):
+  childname = mode_string(go.mode) + "/"
+  childname += name if name else go._ctx.label.name
   if path:
-    filename += "~/" + path
+    childname += "~/" + path
   if ext:
-    filename += ext
-  return go.actions.declare_file(filename)
+    childname += ext
+  return childname
+
+def _declare_file(go, path="", ext="", name = ""):
+  return go.actions.declare_file(_child_name(go, path, ext, name))
+
+def _declare_directory(go, path="", ext="", name = ""):
+  return go.actions.declare_directory(_child_name(go, path, ext, name))
 
 def _new_args(go):
   args = go.actions.args()
@@ -195,20 +201,9 @@ def go_context(ctx, attr=None):
   mode = get_mode(ctx, toolchain, context_data)
   root, binary = _get_go_binary(context_data)
 
-  stdlib = None
-  for check in [s[GoStdLib] for s in context_data.stdlib_all]:
-    if (check.mode.goos == mode.goos and
-        check.mode.goarch == mode.goarch and
-        check.mode.race == mode.race and
-        check.mode.pure == mode.pure):
-      if stdlib:
-        fail("Multiple matching standard library for {}: {} and {}".format(
-          mode_string(mode),
-          check.root_file.dirname,
-          stdlib.root_file.dirname))
-      stdlib = check
-  if not stdlib and context_data.stdlib_all:
-    fail("No matching standard library for "+mode_string(mode))
+  stdlib = getattr(attr, "_stdlib", None)
+  if stdlib:
+    stdlib = get_source(stdlib).stdlib
 
   importpath, pathtype = _infer_importpath(ctx)
   return GoContext(
@@ -241,21 +236,12 @@ def go_context(ctx, attr=None):
       new_library = _new_library,
       library_to_source = _library_to_source,
       declare_file = _declare_file,
+      declare_directory = _declare_directory,
 
       # Private
       _ctx = ctx, # TODO: All uses of this should be removed
   )
 
-def _stdlib_all():
-  stdlibs = []
-  for goos, goarch in GOOS_GOARCH:
-    stdlibs.extend([
-      Label("@go_stdlib_{}_{}_cgo".format(goos, goarch)),
-      Label("@go_stdlib_{}_{}_pure".format(goos, goarch)),
-      Label("@go_stdlib_{}_{}_cgo_race".format(goos, goarch)),
-    ])
-  return stdlibs
-
 def _go_context_data(ctx):
   cpp = ctx.fragments.cpp
   features = ctx.features
@@ -275,7 +261,6 @@ def _go_context_data(ctx):
   compiler_path, _ = cpp.ld_executable.rsplit("/", 1)
   return struct(
       strip = ctx.attr.strip,
-      stdlib_all = ctx.attr.stdlib_all,
       crosstool = ctx.files._crosstool,
       package_list = ctx.file._package_list,
       sdk_files = ctx.files._sdk_files,
@@ -295,7 +280,6 @@ go_context_data = rule(
     _go_context_data,
     attrs = {
         "strip": attr.string(mandatory = True),
-        "stdlib_all": attr.label_list(default = _stdlib_all()),
         # Hidden internal attributes
         "_crosstool": attr.label(default = Label("//tools/defaults:crosstool")),
         "_package_list": attr.label(

go/private/repositories.bzl

@@ -17,7 +17,6 @@
 load("@io_bazel_rules_go//go/private:common.bzl", "MINIMUM_BAZEL_VERSION")
 load("@io_bazel_rules_go//go/private:repository_tools.bzl", "go_repository_tools")
 load("@io_bazel_rules_go//go/private:go_repository.bzl", "go_repository")
-load("@io_bazel_rules_go//go/private:rules/stdlib.bzl", "go_stdlib")
 load("@io_bazel_rules_go//go/private:skylib/lib/versions.bzl", "versions")
 load("@io_bazel_rules_go//go/toolchain:toolchains.bzl", "go_register_toolchains")
 load("@io_bazel_rules_go//go/platform:list.bzl", "GOOS_GOARCH")
@@ -55,29 +54,6 @@ def go_rules_dependencies():
       type = "zip",
   )
 
-  for goos, goarch in GOOS_GOARCH:
-    _maybe(go_stdlib,
-        name = "go_stdlib_{}_{}_cgo".format(goos, goarch),
-        goos = goos,
-        goarch = goarch,
-        race = False,
-        pure = False,
-    )
-    _maybe(go_stdlib,
-        name = "go_stdlib_{}_{}_pure".format(goos, goarch),
-        goos = goos,
-        goarch = goarch,
-        race = False,
-        pure = True,
-    )
-    _maybe(go_stdlib,
-        name = "go_stdlib_{}_{}_cgo_race".format(goos, goarch),
-        goos = goos,
-        goarch = goarch,
-        race = True,
-        pure = False,
-    )
-
   _maybe(go_repository_tools,
       name = "io_bazel_rules_go_repository_tools",
   )

go/private/rules/aspect.bzl

@@ -71,6 +71,7 @@ go_archive_aspect = aspect(
         "embed",
         "compiler",
         "compilers",
+        "_stdlib",
     ],
     attrs = {
         "pure": attr.string(values = [

go/private/rules/rule.bzl

@@ -17,12 +17,18 @@ load(
     "go_archive_aspect",
 )
 
+_ASPECT_ATTRS = ["pure", "static", "msan", "race"]
+
 def go_rule(implementation, attrs={}, toolchains=[], bootstrap=False, **kwargs):
+  attrs["_go_context_data"] = attr.label(default = Label("@io_bazel_rules_go//:go_context_data"))
+  aspects = []
+  # If all the aspect attributes are present, also trigger the aspect on the stdlib attribute
+  if all([k in attrs for k in _ASPECT_ATTRS]):
+    aspects.append(go_archive_aspect)
   if not bootstrap:
-    attrs["_go_context_data"] = attr.label(default = Label("@io_bazel_rules_go//:go_context_data"))
+    attrs["_stdlib"] = attr.label(default = Label("@io_bazel_rules_go//:stdlib"), aspects = aspects)
     toolchains = toolchains + ["@io_bazel_rules_go//go:toolchain"]
   else:
-    attrs["_go_context_data"] = attr.label(default = Label("@io_bazel_rules_go//:go_bootstrap_context_data"))
     toolchains = toolchains + ["@io_bazel_rules_go//go:bootstrap_toolchain"]
 
   return rule(

go/private/rules/stdlib.bzl

@@ -16,90 +16,53 @@ load(
     "@io_bazel_rules_go//go/private:providers.bzl",
     "GoStdLib",
 )
-load("@io_bazel_rules_go//go/private:context.bzl",
+load(
+    "@io_bazel_rules_go//go/private:context.bzl",
     "go_context",
 )
 load(
     "@io_bazel_rules_go//go/private:rules/rule.bzl",
     "go_rule",
 )
 
-_STDLIB_BUILD = """
-load("@io_bazel_rules_go//go/private:rules/stdlib.bzl", "stdlib")
-
-stdlib(
-    name = "{name}",
-    goos = "{goos}",
-    goarch = "{goarch}",
-    race = {race},
-    pure = {pure},
-    visibility = ["//visibility:public"],
-)
-"""
-
-def _stdlib_impl(ctx):
-  go = go_context(ctx)
-  pkg = ctx.actions.declare_directory("pkg")
-  root_file = ctx.actions.declare_file("ROOT")
+def _stdlib_library_to_source(go, attr, source, merge):
+  pkg = go.declare_directory(go, "pkg")
+  root_file = go.declare_file(go, "ROOT")
   files = [root_file, go.go, pkg]
   args = go.args(go)
   args.add(["-out", root_file.dirname])
-  if ctx.attr.race:
+  if go.mode.race:
     args.add("-race")
-  ctx.actions.write(root_file, "")
+  go.actions.write(root_file, "")
   go.actions.run(
       inputs = go.sdk_files + go.sdk_tools + [go.package_list, root_file],
       outputs = [pkg],
       mnemonic = "GoStdlib",
-      executable = ctx.executable._stdlib_builder,
+      executable = attr._stdlib_builder.files.to_list()[0],
       arguments = [args],
   )
+  source["stdlib"] = GoStdLib(
+      root_file = root_file,
+      mode = go.mode,
+      libs = [pkg],
+      headers = [pkg],
+      files = files,
+  )
 
-  return [
-      DefaultInfo(
-          files = depset(files),
-      ),
-      GoStdLib(
-          root_file = root_file,
-          mode = go.mode,
-          libs = [pkg],
-          headers = [pkg],
-          files = files,
-      ),
-  ]
+def _stdlib_impl(ctx):
+  go = go_context(ctx)
+  library = go.new_library(go, resolver = _stdlib_library_to_source)
+  source = go.library_to_source(go, ctx.attr, library, False)
+  return [source, library]
 
 stdlib = go_rule(
     _stdlib_impl,
     bootstrap = True,
     attrs = {
-        "goos": attr.string(mandatory = True),
-        "goarch": attr.string(mandatory = True),
-        "race": attr.bool(mandatory = True),
-        "pure": attr.bool(mandatory = True),
         "_stdlib_builder": attr.label(
             executable = True,
             cfg = "host",
             default = Label("@io_bazel_rules_go//go/tools/builders:stdlib"),
         ),
     },
 )
-
-def _go_stdlib_impl(ctx):
-    ctx.file("BUILD.bazel", _STDLIB_BUILD.format(
-        name = ctx.name,
-        goos = ctx.attr.goos,
-        goarch = ctx.attr.goarch,
-        race = ctx.attr.race,
-        pure = ctx.attr.pure,
-    ))
-
-go_stdlib = repository_rule(
-    implementation = _go_stdlib_impl,
-    attrs = {
-        "goos": attr.string(mandatory = True),
-        "goarch": attr.string(mandatory = True),
-        "race": attr.bool(mandatory = True),
-        "pure": attr.bool(mandatory = True),
-    },
-)
-"""See /go/toolchains.rst#go-sdk for full documentation."""