Add current_*_toolchain rules to allow passing current toolchain inst…

foreign_cc/built_tools/cmake_build.bzl

@@ -6,7 +6,7 @@ def cmake_tool(name, srcs, **kwargs):
     tags = ["manual"] + kwargs.pop("tags", [])
 
     configure_make(
-        name = "_build_{}".format(name),
+        name = "{}.build".format(name),
         configure_command = "bootstrap",
         configure_options = ["--", "-DCMAKE_MAKE_PROGRAM=$$MAKE$$"],
         # On macOS at least -DDEBUG gets set for a fastbuild
@@ -24,7 +24,7 @@ def cmake_tool(name, srcs, **kwargs):
 
     native.filegroup(
         name = name,
-        srcs = ["_build_{}".format(name)],
+        srcs = ["{}.build".format(name)],
         output_group = "gen_dir",
         tags = tags,
     )

toolchains/BUILD.bazel

@@ -2,6 +2,7 @@ load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
 load("//foreign_cc/built_tools:cmake_build.bzl", "cmake_tool")
 load("//foreign_cc/built_tools:make_build.bzl", "make_tool")
 load("//foreign_cc/built_tools:ninja_build.bzl", "ninja_tool")
+load("//toolchains:toolchains.bzl", "current_autoconf_toolchain", "current_automake_toolchain", "current_cmake_toolchain", "current_m4_toolchain", "current_make_toolchain", "current_ninja_toolchain", "current_pkgconfig_toolchain")
 load("//toolchains/native_tools:native_tools_toolchain.bzl", "native_tool_toolchain")
 
 package(default_visibility = ["//visibility:public"])
@@ -34,6 +35,34 @@ toolchain_type(
     name = "automake_toolchain",
 )
 
+current_cmake_toolchain(
+    name = "current_cmake_toolchain",
+)
+
+current_ninja_toolchain(
+    name = "current_ninja_toolchain",
+)
+
+current_m4_toolchain(
+    name = "current_m4_toolchain",
+)
+
+current_pkgconfig_toolchain(
+    name = "current_pkgconfig_toolchain",
+)
+
+current_make_toolchain(
+    name = "current_make_toolchain",
+)
+
+current_automake_toolchain(
+    name = "current_automake_toolchain",
+)
+
+current_autoconf_toolchain(
+    name = "current_autoconf_toolchain",
+)
+
 toolchain(
     name = "built_cmake_toolchain",
     toolchain = ":built_cmake",
@@ -106,6 +135,10 @@ make_tool(
 
 native_tool_toolchain(
     name = "built_make",
+    env = select({
+        "@platforms//os:windows": {"MAKE": "$(execpath :make_tool)/bin/make.exe"},
+        "//conditions:default": {"MAKE": "$(execpath :make_tool)/bin/make"},
+    }),
     path = select({
         "@platforms//os:windows": "$(execpath :make_tool)/bin/make.exe",
         "//conditions:default": "$(execpath :make_tool)/bin/make",
@@ -138,6 +171,10 @@ native_tool_toolchain(
 
 native_tool_toolchain(
     name = "preinstalled_ninja",
+    env = select({
+        "@platforms//os:windows": {"NINJA": "ninja.exe"},
+        "//conditions:default": {"NINJA": "ninja"},
+    }),
     path = select({
         "@platforms//os:windows": "ninja.exe",
         "//conditions:default": "ninja",
@@ -152,6 +189,10 @@ ninja_tool(
 
 native_tool_toolchain(
     name = "built_ninja",
+    env = select({
+        "@platforms//os:windows": {"NINJA": "$(execpath :ninja_tool)/bin/ninja.exe"},
+        "//conditions:default": {"NINJA": "$(execpath :ninja_tool)/bin/ninja"},
+    }),
     path = select({
         "@platforms//os:windows": "$(execpath :ninja_tool)/bin/ninja.exe",
         "//conditions:default": "$(execpath :ninja_tool)/bin/ninja",

toolchains/native_tools/native_tools_toolchain.bzl

@@ -1,7 +1,13 @@
+"""Rules for building native build tools such as ninja, make or cmake"""
+
+# buildifier: disable=bzl-visibility
+load("//foreign_cc/private:framework.bzl", "expand_locations_and_make_variables")
+
 # buildifier: disable=module-docstring
 ToolInfo = provider(
     doc = "Information about the native tool",
     fields = {
+        "env": "Environment variables to set when using this tool e.g. M4",
         "path": (
             "Absolute path to the tool in case the tool is preinstalled on the machine. " +
             "Relative path to the tool in case the tool is built as part of a build; the path should be relative " +
@@ -22,9 +28,12 @@ def _native_tool_toolchain_impl(ctx):
     path = None
     if ctx.attr.target:
         path = ctx.expand_location(ctx.attr.path, targets = [ctx.attr.target])
+        env = expand_locations_and_make_variables(ctx, ctx.attr.env, "env", [ctx.attr.target])
     else:
         path = ctx.expand_location(ctx.attr.path)
+        env = expand_locations_and_make_variables(ctx, ctx.attr.env, "env", [])
     return platform_common.ToolchainInfo(data = ToolInfo(
+        env = env,
         path = path,
         target = ctx.attr.target,
     ))
@@ -38,6 +47,9 @@ native_tool_toolchain = rule(
     ),
     implementation = _native_tool_toolchain_impl,
     attrs = {
+        "env": attr.string_dict(
+            doc = "Environment variables to be set when using this tool e.g. M4",
+        ),
         "path": attr.string(
             mandatory = False,
             doc = (

toolchains/native_tools/tool_access.bzl

@@ -2,50 +2,44 @@
 rules_foreign_cc toolchains
 """
 
-load(":native_tools_toolchain.bzl", "ToolInfo")
-
-def access_tool(toolchain_type_, ctx, tool_name):
+def access_tool(toolchain_type_, ctx):
     """A helper macro for getting the path to a build tool's executable
 
     Args:
         toolchain_type_ (str): The name of the toolchain type
         ctx (ctx): The rule's context object
-        tool_name (str): The name of the tool to query
 
     Returns:
         ToolInfo: A provider containing information about the toolchain's executable
     """
     tool_toolchain = ctx.toolchains[toolchain_type_]
     if tool_toolchain:
         return tool_toolchain.data
-    return ToolInfo(
-        path = tool_name,
-        target = None,
-    )
+    fail("No toolchain found for " + toolchain_type_)
 
 def get_autoconf_data(ctx):
-    return _access_and_expect_label_copied(str(Label("//toolchains:autoconf_toolchain")), ctx, "autoconf")
+    return _access_and_expect_label_copied(str(Label("//toolchains:autoconf_toolchain")), ctx)
 
 def get_automake_data(ctx):
-    return _access_and_expect_label_copied(str(Label("//toolchains:automake_toolchain")), ctx, "automake")
+    return _access_and_expect_label_copied(str(Label("//toolchains:automake_toolchain")), ctx)
 
 def get_cmake_data(ctx):
-    return _access_and_expect_label_copied(str(Label("//toolchains:cmake_toolchain")), ctx, "cmake")
+    return _access_and_expect_label_copied(str(Label("//toolchains:cmake_toolchain")), ctx)
 
 def get_m4_data(ctx):
-    return _access_and_expect_label_copied(str(Label("//toolchains:m4_toolchain")), ctx, "m4")
+    return _access_and_expect_label_copied(str(Label("//toolchains:m4_toolchain")), ctx)
 
 def get_make_data(ctx):
-    return _access_and_expect_label_copied(str(Label("//toolchains:make_toolchain")), ctx, "make")
+    return _access_and_expect_label_copied(str(Label("//toolchains:make_toolchain")), ctx)
 
 def get_ninja_data(ctx):
-    return _access_and_expect_label_copied(str(Label("//toolchains:ninja_toolchain")), ctx, "ninja")
+    return _access_and_expect_label_copied(str(Label("//toolchains:ninja_toolchain")), ctx)
 
 def get_pkgconfig_data(ctx):
-    return _access_and_expect_label_copied(str(Label("//toolchains:pkgconfig_toolchain")), ctx, "pkg-config")
+    return _access_and_expect_label_copied(str(Label("//toolchains:pkgconfig_toolchain")), ctx)
 
-def _access_and_expect_label_copied(toolchain_type_, ctx, tool_name):
-    tool_data = access_tool(toolchain_type_, ctx, tool_name)
+def _access_and_expect_label_copied(toolchain_type_, ctx):
+    tool_data = access_tool(toolchain_type_, ctx)
     if tool_data.target:
         # This could be made more efficient by changing the
         # toolchain to provide the executable as a target
@@ -56,11 +50,13 @@ def _access_and_expect_label_copied(toolchain_type_, ctx, tool_name):
                 break
         return struct(
             deps = [tool_data.target],
+            env = tool_data.env,
             # as the tool will be copied into tools directory
             path = "$EXT_BUILD_ROOT/{}".format(cmd_file.path),
         )
     else:
         return struct(
             deps = [],
+            env = tool_data.env,
             path = tool_data.path,
         )