Bootstrap make reproducibly (#817)

* Make cc_toolchain_utils.bzl more reusable

By using getattr, the helper functions in this file can be reused in
rules that do not define all of the framework attributes, e.g. bootstrap
rules.

* Bootstrap make reproducibly on Linux and macOS

Uses the Bazel C/C++ toolchain to bootstrap make and ensure that the
resulting binary contains no absolute and thus non-hermetic paths.

Building make reproducibly helps with remote caching and removes the
dependency on a C compiler installed on the host.

foreign_cc/built_tools/make_build.bzl

@@ -8,6 +8,13 @@ load(
     "FOREIGN_CC_BUILT_TOOLS_HOST_FRAGMENTS",
     "built_tool_rule_impl",
 )
+load(
+    "//foreign_cc/private:cc_toolchain_util.bzl",
+    "absolutize_path_in_str",
+    "get_env_vars",
+    "get_flags_info",
+    "get_tools_info",
+)
 load("//foreign_cc/private/framework:platform.bzl", "os_name")
 
 def _make_tool_impl(ctx):
@@ -29,8 +36,54 @@ def _make_tool_impl(ctx):
             "cp -p ./{}/gnumake.exe $$INSTALLDIR$$/bin/make.exe".format(dist_dir),
         ]
     else:
+        env = get_env_vars(ctx)
+        flags_info = get_flags_info(ctx)
+        tools_info = get_tools_info(ctx)
+
+        ar_path = tools_info.cxx_linker_static
+        frozen_arflags = flags_info.cxx_linker_static
+
+        cc_path = tools_info.cc
+        cflags = flags_info.cc
+        sysroot_cflags = [flag for flag in cflags if flag.startswith("--sysroot=")]
+        non_sysroot_cflags = [flag for flag in cflags if not flag.startswith("--sysroot=")]
+
+        ld_path = tools_info.cxx_linker_executable
+        ldflags = flags_info.cxx_linker_executable
+        sysroot_ldflags = [flag for flag in ldflags if flag.startswith("--sysroot=")]
+        non_sysroot_ldflags = [flag for flag in ldflags if not flag.startswith("--sysroot=")]
+
+        # Make's build script does not forward CFLAGS to all compiler and linker
+        # invocations, so we append --sysroot flags directly to CC and LD.
+        absolute_cc = _absolutize(ctx.workspace_name, cc_path, True)
+        if sysroot_cflags:
+            absolute_cc += " " + _join_flags_list(ctx.workspace_name, sysroot_cflags)
+        absolute_ld = _absolutize(ctx.workspace_name, ld_path, True)
+        if sysroot_ldflags:
+            absolute_ld += " " + _join_flags_list(ctx.workspace_name, sysroot_ldflags)
+
+        # If libtool is used as AR, the output file has to be prefixed with
+        # "-o". Since the make Makefile only uses ar-style invocations, the
+        # output file always comes first and we can append this argument to the
+        # flags list.
+        absolute_ar = _absolutize(ctx.workspace_name, ar_path, True)
+        arflags = [e for e in frozen_arflags]
+        if absolute_ar == "libtool" or absolute_ar.endswith("/libtool"):
+            arflags.append("-o")
+
+        env.update({
+            "AR": absolute_ar,
+            "ARFLAGS": _join_flags_list(ctx.workspace_name, arflags),
+            "CC": absolute_cc,
+            "CFLAGS": _join_flags_list(ctx.workspace_name, non_sysroot_cflags),
+            "LD": absolute_ld,
+            "LDFLAGS": _join_flags_list(ctx.workspace_name, non_sysroot_ldflags),
+        })
+
+        configure_env = " ".join(["%s=\"%s\"" % (key, value) for key, value in env.items()])
         script = [
-            "./configure --without-guile --with-guile=no --disable-dependency-tracking --prefix=$$INSTALLDIR$$",
+            "%s ./configure --without-guile --with-guile=no --disable-dependency-tracking --prefix=$$INSTALLDIR$$" % configure_env,
+            "cat build.cfg",
             "./build.sh",
             "./make install",
         ]
@@ -54,3 +107,9 @@ make_tool = rule(
         "@bazel_tools//tools/cpp:toolchain_type",
     ],
 )
+
+def _absolutize(workspace_name, text, force = False):
+    return absolutize_path_in_str(workspace_name, "$$EXT_BUILD_ROOT$$/", text, force)
+
+def _join_flags_list(workspace_name, flags):
+    return " ".join([_absolutize(workspace_name, flag) for flag in flags])

foreign_cc/private/cc_toolchain_util.bzl

@@ -118,7 +118,7 @@ def _files_map(files_list):
     return by_names_map
 
 def _defines_from_deps(ctx):
-    return depset(transitive = [dep[CcInfo].compilation_context.defines for dep in ctx.attr.deps])
+    return depset(transitive = [dep[CcInfo].compilation_context.defines for dep in getattr(ctx.attr, "deps", [])])
 
 def _build_cc_link_params(
         ctx,
@@ -301,9 +301,9 @@ def get_flags_info(ctx, link_output_file = None):
         cc_toolchain = cc_toolchain_,
     )
 
-    copts = (ctx.fragments.cpp.copts + ctx.fragments.cpp.conlyopts + ctx.attr.copts) or []
+    copts = (ctx.fragments.cpp.copts + ctx.fragments.cpp.conlyopts + getattr(ctx.attr, "copts", [])) or []
-    cxxopts = (ctx.fragments.cpp.copts + ctx.fragments.cpp.cxxopts + ctx.attr.copts) or []
+    cxxopts = (ctx.fragments.cpp.copts + ctx.fragments.cpp.cxxopts + getattr(ctx.attr, "copts", [])) or []
-    linkopts = (ctx.fragments.cpp.linkopts + ctx.attr.linkopts) or []
+    linkopts = (ctx.fragments.cpp.linkopts + getattr(ctx.attr, "linkopts", [])) or []
     defines = _defines_from_deps(ctx)
 
     flags = CxxFlagsInfo(

toolchains/built_toolchains.bzl

@@ -412,6 +412,7 @@ def _make_toolchain(version):
             http_archive,
             name = "gnumake_src",
             build_file_content = _ALL_CONTENT,
+            patches = ["@rules_foreign_cc//toolchains:make-reproducible-bootstrap.patch"],
             sha256 = "e05fdde47c5f7ca45cb697e973894ff4f5d79e13b750ed57d7b66d8defc78e19",
             strip_prefix = "make-4.3",
             urls = [

toolchains/make-reproducible-bootstrap.patch

@@ -0,0 +1,16 @@
+diff --git Makefile.in Makefile.in
+index 9535058..0b12e99 100644
+--- Makefile.in
++++ Makefile.in
+@@ -1042,8 +1042,8 @@ make_LDADD = $(LIBOBJS) $(GUILE_LIBS) lib/libgnu.a $(GETLOADAVG_LIBS) \
+ 		@LIBINTL@
+
+ AM_CPPFLAGS = -Isrc -I$(top_srcdir)/src -Ilib -I$(top_srcdir)/lib \
+-	-DLIBDIR=\"$(libdir)\" -DINCLUDEDIR=\"$(includedir)\" \
+-	-DLOCALEDIR=\"$(localedir)\" $(am__append_2)
++	-DLIBDIR=\".\" -DINCLUDEDIR=\"external/rules_foreign_cc/toolchains/make/include\" \
++	-DLOCALEDIR=\"external/rules_foreign_cc/toolchains/make/share/locale\" $(am__append_2)
+ AM_CFLAGS = $(GUILE_CFLAGS)
+
+ # Extra stuff to include in the distribution.
+