From 62e2e7069986cb2a7a5fb62adf68bfed993888c6 Mon Sep 17 00:00:00 2001
From: Malte Poll <1780588+malt3@users.noreply.github.com>
Date: Thu, 16 Mar 2023 16:13:48 +0100
Subject: [PATCH] bazel: use host platform by default (#1434)

---
 .bazelrc                                  |  3 --
 CMakeLists.txt                            | 28 ++++++-------
 bazel/devbuild/BUILD.bazel                |  8 ++--
 bazel/go/platform.bzl                     | 49 +++++++++++++++++++++++
 bootstrapper/cmd/bootstrapper/BUILD.bazel |  8 ++++
 debugd/cmd/debugd/BUILD.bazel             |  8 ++++
 disk-mapper/cmd/BUILD.bazel               |  8 ++++
 measurement-reader/cmd/BUILD.bazel        |  8 ++++
 upgrade-agent/cmd/BUILD.bazel             |  8 ++++
 9 files changed, 107 insertions(+), 21 deletions(-)
 create mode 100644 bazel/go/platform.bzl

diff --git a/.bazelrc b/.bazelrc
index cecc519ec..6ec0b5b0b 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -20,9 +20,6 @@ build --strip=always
 # set build mode to opt by default (better reproducibility and performance)
 build --compilation_mode=opt
 
-# compile for linux_amd64 by default (this is the target for any binaries that go into the cluster)
-build --platforms @zig_sdk//libc_aware/platform:linux_amd64_gnu.2.34
-
 # enable tpm simulator for tests
 test --//bazel/settings:tpm_simulator
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3dc574579..714bacdb6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,8 +9,8 @@ enable_testing()
 # disk-mapper
 #
 add_custom_target(disk-mapper ALL
-  COMMAND ${BAZEL} build //disk-mapper/cmd:cmd
-  COMMAND cp \$$\(${BAZEL} cquery --output=files //disk-mapper/cmd:cmd\) ${CMAKE_BINARY_DIR}/disk-mapper
+  COMMAND ${BAZEL} build //disk-mapper/cmd:disk-mapper_linux_amd64
+  COMMAND cp \$$\(${BAZEL} cquery --output=files //disk-mapper/cmd:disk-mapper_linux_amd64\) ${CMAKE_BINARY_DIR}/disk-mapper
   COMMAND chmod +w ${CMAKE_BINARY_DIR}/disk-mapper
   WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
   BYPRODUCTS disk-mapper
@@ -20,8 +20,8 @@ add_custom_target(disk-mapper ALL
 # measurement-reader
 #
 add_custom_target(measurement-reader ALL
-  COMMAND ${BAZEL} build //measurement-reader/cmd:cmd
-  COMMAND cp \$$\(${BAZEL} cquery --output=files //measurement-reader/cmd:cmd\) ${CMAKE_BINARY_DIR}/measurement-reader
+  COMMAND ${BAZEL} build //measurement-reader/cmd:measurement-reader_linux_amd64
+  COMMAND cp \$$\(${BAZEL} cquery --output=files //measurement-reader/cmd:measurement-reader_linux_amd64\) ${CMAKE_BINARY_DIR}/measurement-reader
   COMMAND chmod +w ${CMAKE_BINARY_DIR}/measurement-reader
   WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
   BYPRODUCTS measurement-reader
@@ -31,8 +31,8 @@ add_custom_target(measurement-reader ALL
 # bootstrapper
 #
 add_custom_target(bootstrapper ALL
-  COMMAND ${BAZEL} build //bootstrapper/cmd/bootstrapper:bootstrapper
-  COMMAND cp \$$\(${BAZEL} cquery --output=files //bootstrapper/cmd/bootstrapper:bootstrapper\) ${CMAKE_BINARY_DIR}/bootstrapper
+  COMMAND ${BAZEL} build //bootstrapper/cmd/bootstrapper:bootstrapper_linux_amd64
+  COMMAND cp \$$\(${BAZEL} cquery --output=files //bootstrapper/cmd/bootstrapper:bootstrapper_linux_amd64\) ${CMAKE_BINARY_DIR}/bootstrapper
   COMMAND chmod +w ${CMAKE_BINARY_DIR}/bootstrapper
   WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
   BYPRODUCTS bootstrapper
@@ -42,8 +42,8 @@ add_custom_target(bootstrapper ALL
 # upgrade-agent
 #
 add_custom_target(upgrade-agent ALL
-  COMMAND ${BAZEL} build //upgrade-agent/cmd:cmd
-  COMMAND cp \$$\(${BAZEL} cquery --output=files //upgrade-agent/cmd:cmd\) ${CMAKE_BINARY_DIR}/upgrade-agent
+  COMMAND ${BAZEL} build //upgrade-agent/cmd:upgrade_agent_linux_amd64
+  COMMAND cp \$$\(${BAZEL} cquery --output=files //upgrade-agent/cmd:upgrade_agent_linux_amd64\) ${CMAKE_BINARY_DIR}/upgrade-agent
   COMMAND chmod +w ${CMAKE_BINARY_DIR}/upgrade-agent
   WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
   BYPRODUCTS upgrade-agent
@@ -53,8 +53,8 @@ add_custom_target(upgrade-agent ALL
 # cli
 #
 add_custom_target(cli ALL
-  COMMAND ${BAZEL} build --@io_bazel_rules_go//go/config:tags='${CLI_BUILD_TAGS}' --platforms=@local_config_platform//:host //cli:cli_oss
-  COMMAND cp \$$\(${BAZEL} cquery --@io_bazel_rules_go//go/config:tags='${CLI_BUILD_TAGS}' --platforms=@local_config_platform//:host --output=files //cli:cli_oss\) ${CMAKE_BINARY_DIR}/constellation
+  COMMAND ${BAZEL} build --@io_bazel_rules_go//go/config:tags='${CLI_BUILD_TAGS}' //cli:cli_oss_host
+  COMMAND cp \$$\(${BAZEL} cquery --@io_bazel_rules_go//go/config:tags='${CLI_BUILD_TAGS}' --output=files //cli:cli_oss_host\) ${CMAKE_BINARY_DIR}/constellation
   COMMAND chmod +w ${CMAKE_BINARY_DIR}/constellation
   WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
   BYPRODUCTS constellation
@@ -64,8 +64,8 @@ add_custom_target(cli ALL
 # debugd
 #
 add_custom_target(debugd ALL
-  COMMAND ${BAZEL} build //debugd/cmd/debugd:debugd
-  COMMAND cp \$$\(${BAZEL} cquery --output=files //debugd/cmd/debugd:debugd\) ${CMAKE_BINARY_DIR}/debugd
+  COMMAND ${BAZEL} build //debugd/cmd/debugd:debugd_linux_amd64
+  COMMAND cp \$$\(${BAZEL} cquery --output=files //debugd/cmd/debugd:debugd_linux_amd64\) ${CMAKE_BINARY_DIR}/debugd
   COMMAND chmod +w ${CMAKE_BINARY_DIR}/debugd
   WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
   BYPRODUCTS debugd
@@ -75,8 +75,8 @@ add_custom_target(debugd ALL
 # cdbg
 #
 add_custom_target(cdbg ALL
-  COMMAND ${BAZEL} build --platforms=@local_config_platform//:host //debugd/cmd/cdbg:cdbg
-  COMMAND cp \$$\(${BAZEL} cquery --platforms=@local_config_platform//:host --output=files //debugd/cmd/cdbg:cdbg\) ${CMAKE_BINARY_DIR}/cdbg
+  COMMAND ${BAZEL} build //debugd/cmd/cdbg:cdbg_host
+  COMMAND cp \$$\(${BAZEL} cquery --output=files //debugd/cmd/cdbg:cdbg_host\) ${CMAKE_BINARY_DIR}/cdbg
   COMMAND chmod +w ${CMAKE_BINARY_DIR}/cdbg
   WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
   BYPRODUCTS cdbg
diff --git a/bazel/devbuild/BUILD.bazel b/bazel/devbuild/BUILD.bazel
index 73220965d..f6fa68537 100644
--- a/bazel/devbuild/BUILD.bazel
+++ b/bazel/devbuild/BUILD.bazel
@@ -3,16 +3,16 @@ load("//bazel/sh:def.bzl", "sh_template")
 sh_template(
     name = "devbuild",
     data = [
-        "//bootstrapper/cmd/bootstrapper",
+        "//bootstrapper/cmd/bootstrapper:bootstrapper_linux_amd64",
         "//cli:cli_oss_host",
         "//debugd/cmd/cdbg:cdbg_host",
-        "//upgrade-agent/cmd",
+        "//upgrade-agent/cmd:upgrade_agent_linux_amd64",
     ],
     substitutions = {
-        "@@BOOTSTRAPPER@@": "$(rootpath //bootstrapper/cmd/bootstrapper)",
+        "@@BOOTSTRAPPER@@": "$(rootpath //bootstrapper/cmd/bootstrapper:bootstrapper_linux_amd64)",
         "@@CDBG@@": "$(rootpath //debugd/cmd/cdbg:cdbg_host)",
         "@@CLI@@": "$(rootpath //cli:cli_oss_host)",
-        "@@UPGRADE_AGENT@@": "$(rootpath //upgrade-agent/cmd)",
+        "@@UPGRADE_AGENT@@": "$(rootpath //upgrade-agent/cmd:upgrade_agent_linux_amd64)",
     },
     template = "prepare_developer_workspace.sh.in",
     visibility = ["//visibility:public"],
diff --git a/bazel/go/platform.bzl b/bazel/go/platform.bzl
new file mode 100644
index 000000000..c4e48ec1e
--- /dev/null
+++ b/bazel/go/platform.bzl
@@ -0,0 +1,49 @@
+"""A rule to build a single executable for a specific platform."""
+
+def _platform_transition_impl(settings, attr):
+    _ignore = settings  # @unused
+    return {
+        "//command_line_option:platforms": "{}".format(attr.platform),
+    }
+
+_platform_transition = transition(
+    implementation = _platform_transition_impl,
+    inputs = [],
+    outputs = [
+        "//command_line_option:platforms",
+    ],
+)
+
+def _platform_binary_impl(ctx):
+    out = ctx.actions.declare_file("{}_{}".format(ctx.file.target_file.basename, ctx.attr.platform))
+    ctx.actions.symlink(output = out, target_file = ctx.file.target_file)
+
+    return [
+        DefaultInfo(
+            executable = out,
+            files = depset([out]),
+            runfiles = ctx.runfiles(files = ctx.files.target_file),
+        ),
+    ]
+
+_attrs = {
+    "platform": attr.string(
+        doc = "The platform to build the target for.",
+    ),
+    "target_file": attr.label(
+        allow_single_file = True,
+        mandatory = True,
+        doc = "Target to build.",
+    ),
+    "_allowlist_function_transition": attr.label(
+        default = "@bazel_tools//tools/allowlists/function_transition_allowlist",
+    ),
+}
+
+# wrap a single exectable and build it for the specified platform.
+platform_binary = rule(
+    implementation = _platform_binary_impl,
+    cfg = _platform_transition,
+    attrs = _attrs,
+    executable = True,
+)
diff --git a/bootstrapper/cmd/bootstrapper/BUILD.bazel b/bootstrapper/cmd/bootstrapper/BUILD.bazel
index 654b24171..3f843316d 100644
--- a/bootstrapper/cmd/bootstrapper/BUILD.bazel
+++ b/bootstrapper/cmd/bootstrapper/BUILD.bazel
@@ -1,4 +1,5 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+load("//bazel/go:platform.bzl", "platform_binary")
 
 go_library(
     name = "bootstrapper_lib",
@@ -54,3 +55,10 @@ go_binary(
     }),
     visibility = ["//visibility:public"],
 )
+
+platform_binary(
+    name = "bootstrapper_linux_amd64",
+    platform = "@zig_sdk//libc_aware/platform:linux_amd64_gnu.2.34",
+    target_file = ":bootstrapper",
+    visibility = ["//visibility:public"],
+)
diff --git a/debugd/cmd/debugd/BUILD.bazel b/debugd/cmd/debugd/BUILD.bazel
index 3fca6914b..6e6e1b8bd 100644
--- a/debugd/cmd/debugd/BUILD.bazel
+++ b/debugd/cmd/debugd/BUILD.bazel
@@ -1,4 +1,5 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+load("//bazel/go:platform.bzl", "platform_binary")
 
 go_library(
     name = "debugd_lib",
@@ -33,3 +34,10 @@ go_binary(
     pure = "on",
     visibility = ["//visibility:public"],
 )
+
+platform_binary(
+    name = "debugd_linux_amd64",
+    platform = "@zig_sdk//libc_aware/platform:linux_amd64_gnu.2.34",
+    target_file = ":debugd",
+    visibility = ["//visibility:public"],
+)
diff --git a/disk-mapper/cmd/BUILD.bazel b/disk-mapper/cmd/BUILD.bazel
index 93e87730a..0022857ff 100644
--- a/disk-mapper/cmd/BUILD.bazel
+++ b/disk-mapper/cmd/BUILD.bazel
@@ -1,4 +1,5 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+load("//bazel/go:platform.bzl", "platform_binary")
 
 go_library(
     name = "cmd_lib",
@@ -35,3 +36,10 @@ go_binary(
     embed = [":cmd_lib"],
     visibility = ["//visibility:public"],
 )
+
+platform_binary(
+    name = "disk-mapper_linux_amd64",
+    platform = "@zig_sdk//libc_aware/platform:linux_amd64_gnu.2.34",
+    target_file = ":cmd",
+    visibility = ["//visibility:public"],
+)
diff --git a/measurement-reader/cmd/BUILD.bazel b/measurement-reader/cmd/BUILD.bazel
index 5006b7b91..ae341d987 100644
--- a/measurement-reader/cmd/BUILD.bazel
+++ b/measurement-reader/cmd/BUILD.bazel
@@ -1,4 +1,5 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+load("//bazel/go:platform.bzl", "platform_binary")
 
 go_library(
     name = "cmd_lib",
@@ -21,3 +22,10 @@ go_binary(
     embed = [":cmd_lib"],
     visibility = ["//visibility:public"],
 )
+
+platform_binary(
+    name = "measurement-reader_linux_amd64",
+    platform = "@zig_sdk//libc_aware/platform:linux_amd64_gnu.2.34",
+    target_file = ":cmd",
+    visibility = ["//visibility:public"],
+)
diff --git a/upgrade-agent/cmd/BUILD.bazel b/upgrade-agent/cmd/BUILD.bazel
index a2567ae1b..e1cc48bdd 100644
--- a/upgrade-agent/cmd/BUILD.bazel
+++ b/upgrade-agent/cmd/BUILD.bazel
@@ -1,4 +1,5 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+load("//bazel/go:platform.bzl", "platform_binary")
 
 go_library(
     name = "cmd_lib",
@@ -22,3 +23,10 @@ go_binary(
     pure = "on",
     visibility = ["//visibility:public"],
 )
+
+platform_binary(
+    name = "upgrade_agent_linux_amd64",
+    platform = "@zig_sdk//libc_aware/platform:linux_amd64_gnu.2.34",
+    target_file = ":cmd",
+    visibility = ["//visibility:public"],
+)