From 6b0243e97d94836767ea8b94a477d7d15ee3bb91 Mon Sep 17 00:00:00 2001
From: Zachary Anderson <zanderso@users.noreply.github.com>
Date: Thu, 31 Aug 2023 09:34:39 -0700
Subject: [PATCH] RBE (#758)

See instructions on https://github.com/flutter/engine/pull/45271
---
 build/rbe.cfg                     |  9 +++++
 build/toolchain/android/BUILD.gn  | 31 ++++++++++++++--
 build/toolchain/gcc_toolchain.gni | 19 ++++++++--
 build/toolchain/linux/BUILD.gn    | 59 ++++++++++++++++++++++++-------
 build/toolchain/rbe.gni           | 33 +++++++++++++++++
 build/toolchain/wasm.gni          |  1 +
 6 files changed, 134 insertions(+), 18 deletions(-)
 create mode 100644 build/rbe.cfg
 create mode 100644 build/toolchain/rbe.gni

diff --git a/build/rbe.cfg b/build/rbe.cfg
new file mode 100644
index 0000000000..9065cdd893
--- /dev/null
+++ b/build/rbe.cfg
@@ -0,0 +1,9 @@
+service=remotebuildexecution.googleapis.com:443
+instance=projects/flutter-rbe-prod/instances/default
+use_application_default_credentials=true
+enable_deps_cache=true
+xattr_digest=user.flutter.rbe.digest.sha256
+server_address=unix:///tmp/reproxy.sock
+log_dir=/tmp
+proxy_log_dir=/tmp
+log_format=reducedtext
diff --git a/build/toolchain/android/BUILD.gn b/build/toolchain/android/BUILD.gn
index eb1cce98f7..bf6f19bf23 100644
--- a/build/toolchain/android/BUILD.gn
+++ b/build/toolchain/android/BUILD.gn
@@ -7,6 +7,7 @@ import("//build/toolchain/ccache.gni")
 import("//build/toolchain/clang.gni")
 import("//build/toolchain/gcc_toolchain.gni")
 import("//build/toolchain/goma.gni")
+import("//build/toolchain/rbe.gni")
 
 # The Android GCC toolchains share most of the same parameters, so we have this
 # wrapper around gcc_toolchain to avoid duplication of logic.
@@ -35,10 +36,31 @@ template("android_gcc_toolchain") {
     if (use_goma) {
       assert(!use_ccache, "Goma and ccache can't be used together.")
       compiler_prefix = "$goma_dir/gomacc "
+      link_prefix = "$goma_dir/gomacc "
+    } else if (use_rbe) {
+      assert(!use_goma)
+      rewrapper_args = [
+        "$rbe_dir/rewrapper",
+        "--server_address=$rbe_server_address",
+        "--exec_strategy=$rbe_exec_strategy",
+        "--dial_timeout=$rbe_dial_timeout",
+        "--exec_root=$rbe_exec_root",
+        "--platform=$rbe_platform",
+      ]
+      compiler_args = rewrapper_args + [
+        "--labels=type=compile,compiler=clang,lang=cpp ",
+      ]
+      link_args = rewrapper_args + [
+        "--labels=type=link,tool=clang ",
+      ]
+      compiler_prefix = string_join(" ", compiler_args)
+      link_prefix = string_join(" ", link_args)
     } else if (use_ccache) {
       compiler_prefix = "ccache "
+      link_prefix = "ccache "
     } else {
       compiler_prefix = ""
+      link_prefix = ""
     }
 
     is_clang = invoker.is_clang
@@ -54,18 +76,21 @@ template("android_gcc_toolchain") {
 
       prefix = rebase_path("//buildtools/$host_dir/clang/bin", root_build_dir)
 
+      asm = prefix + "/clang"
       cc = compiler_prefix + prefix + "/clang"
       cxx = compiler_prefix + prefix + "/clang++"
       ar = prefix + "/llvm-ar"
+      ld = link_prefix + prefix + "/clang++"
     } else {
+      asm = tool_prefix + "gcc"
       cc = compiler_prefix + tool_prefix + "gcc"
       cxx = compiler_prefix + tool_prefix + "g++"
       ar = tool_prefix + "ar"
+      ld = link_prefix + tool_prefix + "g++"
     }
 
-    ld = cxx
-    readelf = compiler_prefix + tool_prefix + "readelf"
-    nm = compiler_prefix + tool_prefix + "nm"
+    readelf = tool_prefix + "readelf"
+    nm = tool_prefix + "nm"
 
     toolchain_os = "android"
     toolchain_cpu = invoker.toolchain_cpu
diff --git a/build/toolchain/gcc_toolchain.gni b/build/toolchain/gcc_toolchain.gni
index d0922eac68..d1fb2901b5 100644
--- a/build/toolchain/gcc_toolchain.gni
+++ b/build/toolchain/gcc_toolchain.gni
@@ -4,6 +4,7 @@
 
 import("//build/toolchain/clang.gni")
 import("//build/toolchain/clang_static_analyzer.gni")
+import("//build/toolchain/rbe.gni")
 
 # Path to the Clang static analysis wrapper script.
 analyzer_wrapper =
@@ -14,6 +15,7 @@ analyzer_wrapper =
 # (including clang).
 #
 # It requires the following variables specifying the executables to run:
+#  - asm
 #  - cc
 #  - cxx
 #  - ar
@@ -50,6 +52,7 @@ analyzer_wrapper =
 #      when specified.
 template("gcc_toolchain") {
   toolchain(target_name) {
+    assert(defined(invoker.asm), "gcc_toolchain() must specify a \"asm\" value")
     assert(defined(invoker.cc), "gcc_toolchain() must specify a \"cc\" value")
     assert(defined(invoker.cxx), "gcc_toolchain() must specify a \"cxx\" value")
     assert(defined(invoker.ar), "gcc_toolchain() must specify a \"ar\" value")
@@ -76,6 +79,7 @@ template("gcc_toolchain") {
     # We can't do string interpolation ($ in strings) on things with dots in
     # them. To allow us to use $cc below, for example, we create copies of
     # these values in our scope.
+    asm = invoker.asm
     cc = compiler_prefix + invoker.cc
     cxx = compiler_prefix + invoker.cxx
     ar = invoker.ar
@@ -120,6 +124,12 @@ template("gcc_toolchain") {
     tool("cc") {
       depfile = "{{output}}.d"
       command = "$cc -MD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_c}} $coverage_flags -c {{source}} -o {{output}}"
+      if (use_rbe) {
+        # The depfile generated on an RBE worker can contain absolute paths.
+        # This sed command strips off the prefix, and rewrites to be
+        # relative to the buildroot.
+        command += " && sed -i 's@/b/f/w@../..@g' $depfile"
+      }
       depsformat = "gcc"
       description = "CC {{output}}"
       outputs = [
@@ -130,6 +140,9 @@ template("gcc_toolchain") {
     tool("cxx") {
       depfile = "{{output}}.d"
       command = "$cxx -MD -MF $depfile {{defines}} {{include_dirs}} {{cflags}} {{cflags_cc}}  $coverage_flags -c {{source}} -o {{output}}"
+      if (use_rbe) {
+        command += " && sed -i 's@/b/f/w@../..@g' $depfile"
+      }
       depsformat = "gcc"
       description = "CXX {{output}}"
       outputs = [
@@ -138,9 +151,11 @@ template("gcc_toolchain") {
     }
 
     tool("asm") {
-      # For GCC we can just use the C compiler to compile assembly.
       depfile = "{{output}}.d"
-      command = "$cc -MD -MF $depfile {{defines}} {{include_dirs}} {{asmflags}} {{cflags}} {{cflags_c}} $coverage_flags -c {{source}} -o {{output}}"
+      command = "$asm -MD -MF $depfile {{defines}} {{include_dirs}} {{asmflags}} {{cflags}} {{cflags_c}} $coverage_flags -c {{source}} -o {{output}}"
+      if (use_rbe) {
+        command += " && sed -i 's@/b/f/w@../..@g' $depfile"
+      }
       depsformat = "gcc"
       description = "ASM {{output}}"
       outputs = [
diff --git a/build/toolchain/linux/BUILD.gn b/build/toolchain/linux/BUILD.gn
index 05630d01e7..dec1ab833d 100644
--- a/build/toolchain/linux/BUILD.gn
+++ b/build/toolchain/linux/BUILD.gn
@@ -6,19 +6,40 @@ import("//build/config/sysroot.gni")
 import("//build/toolchain/ccache.gni")
 import("//build/toolchain/gcc_toolchain.gni")
 import("//build/toolchain/goma.gni")
+import("//build/toolchain/rbe.gni")
 
 declare_args() {
   toolchain_prefix = ""
-  # TODO(zra): Add an argument for overriding the host toolchain.
 }
 
 if (use_goma) {
   assert(!use_ccache, "Goma and ccache can't be used together.")
   compiler_prefix = "$goma_dir/gomacc "
+  link_prefix = "$goma_dir/gomacc "
+} else if (use_rbe) {
+  assert(!use_goma)
+  rewrapper_args = [
+    "$rbe_dir/rewrapper",
+    "--server_address=$rbe_server_address",
+    "--exec_strategy=$rbe_exec_strategy",
+    "--dial_timeout=$rbe_dial_timeout",
+    "--exec_root=$rbe_exec_root",
+    "--platform=$rbe_platform",
+  ]
+  compiler_args = rewrapper_args + [
+    "--labels=type=compile,compiler=clang,lang=cpp ",
+  ]
+  link_args = rewrapper_args + [
+    "--labels=type=link,tool=clang ",
+  ]
+  compiler_prefix = string_join(" ", compiler_args)
+  link_prefix = string_join(" ", link_args)
 } else if (use_ccache) {
   compiler_prefix = "ccache "
+  link_prefix = "ccache "
 } else {
   compiler_prefix = ""
+  link_prefix = ""
 }
 
 if (host_cpu == "arm64") {
@@ -35,11 +56,12 @@ gcc_toolchain("arm") {
     prefix = toolchain_prefix
   }
 
+  asm = "${prefix}gcc"
   cc = "${compiler_prefix}${prefix}gcc"
   cxx = "${compiler_prefix}${prefix}g++"
 
   ar = "${prefix}ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}g++"
   readelf = "${prefix}readelf"
   nm = "${prefix}nm"
   strip = "${prefix}strip"
@@ -51,13 +73,14 @@ gcc_toolchain("arm") {
 
 gcc_toolchain("clang_arm") {
   prefix = rebased_clang_dir
+  asm = "${prefix}/clang"
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
 
   readelf = "${prefix}/llvm-readelf"
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}/clang++"
   llvm_objcopy = "${prefix}/llvm-objcopy"
 
   toolchain_cpu = "arm"
@@ -71,11 +94,12 @@ gcc_toolchain("arm64") {
     prefix = toolchain_prefix
   }
 
+  asm = "${prefix}gcc"
   cc = "${compiler_prefix}${prefix}gcc"
   cxx = "${compiler_prefix}${prefix}g++"
 
   ar = "${prefix}ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}g++"
   readelf = "${prefix}readelf"
   nm = "${prefix}nm"
   strip = "${prefix}strip"
@@ -87,13 +111,14 @@ gcc_toolchain("arm64") {
 
 gcc_toolchain("clang_arm64") {
   prefix = rebased_clang_dir
+  asm = "${prefix}/clang"
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
 
   readelf = "readelf"
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}/clang++"
   llvm_objcopy = "${prefix}/llvm-objcopy"
 
   toolchain_cpu = "arm64"
@@ -103,13 +128,14 @@ gcc_toolchain("clang_arm64") {
 
 gcc_toolchain("clang_x86") {
   prefix = rebased_clang_dir
+  asm = "${prefix}/clang"
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
 
   readelf = "${prefix}/llvm-readelf"
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}/clang++"
   llvm_objcopy = "${prefix}/llvm-objcopy"
 
   toolchain_cpu = "x86"
@@ -119,13 +145,14 @@ gcc_toolchain("clang_x86") {
 
 gcc_toolchain("x86") {
   prefix = ""
+  asm = "${prefix}gcc"
   cc = "${compiler_prefix}${prefix}gcc"
   cxx = "${compiler_prefix}${prefix}g++"
 
   readelf = "${prefix}readelf"
   nm = "${prefix}nm"
   ar = "${prefix}ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}g++"
   strip = "${prefix}strip"
 
   toolchain_cpu = "x86"
@@ -135,13 +162,14 @@ gcc_toolchain("x86") {
 
 gcc_toolchain("clang_x64") {
   prefix = rebased_clang_dir
+  asm = "${prefix}/clang"
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
 
   readelf = "${prefix}/llvm-readelf"
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}/clang++"
   llvm_objcopy = "${prefix}/llvm-objcopy"
 
   toolchain_cpu = "x64"
@@ -151,13 +179,14 @@ gcc_toolchain("clang_x64") {
 
 gcc_toolchain("x64") {
   prefix = ""
+  asm = "${prefix}gcc"
   cc = "${compiler_prefix}${prefix}gcc"
   cxx = "${compiler_prefix}${prefix}g++"
 
   readelf = "${prefix}readelf"
   nm = "${prefix}nm"
   ar = "${prefix}ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}g++"
   strip = "${prefix}strip"
 
   toolchain_cpu = "x64"
@@ -171,11 +200,12 @@ gcc_toolchain("riscv32") {
     prefix = toolchain_prefix
   }
 
+  asm = "${prefix}gcc"
   cc = "${compiler_prefix}${prefix}gcc"
   cxx = "${compiler_prefix}${prefix}g++"
 
   ar = "${prefix}ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}g++"
   readelf = "${prefix}readelf"
   nm = "${prefix}nm"
   strip = "${prefix}strip"
@@ -187,13 +217,14 @@ gcc_toolchain("riscv32") {
 
 gcc_toolchain("clang_riscv32") {
   prefix = rebased_clang_dir
+  asm = "${prefix}/clang"
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
 
   readelf = "readelf"
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}/clang++"
   llvm_objcopy = "${prefix}/llvm-objcopy"
 
   toolchain_cpu = "riscv32"
@@ -207,11 +238,12 @@ gcc_toolchain("riscv64") {
     prefix = toolchain_prefix
   }
 
+  asm = "${prefix}gcc"
   cc = "${compiler_prefix}${prefix}gcc"
   cxx = "${compiler_prefix}${prefix}g++"
 
   ar = "${prefix}ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}g++"
   readelf = "${prefix}readelf"
   nm = "${prefix}nm"
   strip = "${prefix}strip"
@@ -223,13 +255,14 @@ gcc_toolchain("riscv64") {
 
 gcc_toolchain("clang_riscv64") {
   prefix = rebased_clang_dir
+  asm = "${prefix}/clang"
   cc = "${compiler_prefix}${prefix}/clang"
   cxx = "${compiler_prefix}${prefix}/clang++"
 
   readelf = "readelf"
   nm = "${prefix}/llvm-nm"
   ar = "${prefix}/llvm-ar"
-  ld = cxx
+  ld = "${link_prefix}${prefix}/clang++"
   llvm_objcopy = "${prefix}/llvm-objcopy"
 
   toolchain_cpu = "riscv64"
diff --git a/build/toolchain/rbe.gni b/build/toolchain/rbe.gni
new file mode 100644
index 0000000000..0f29e52fd1
--- /dev/null
+++ b/build/toolchain/rbe.gni
@@ -0,0 +1,33 @@
+# Copyright (c) 2013 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Defines the configuration of RBE.
+
+declare_args() {
+  # Set to true to enable distributed compilation using Goma.
+  use_rbe = false
+
+  # Set to true to create symlinks to Xcode toolchain/SDK directories.
+  #
+  # RBE does not allow for include paths outside of the buildroot. Creating
+  # symlinks is a work around for that when using a local Xcode toolchain.
+  # This property should not be set to true on LUCI.
+  #
+  # If use_goma is false, this property is ignored.
+  # create_xcode_symlinks = false
+
+  rbe_exec_root = rebase_path("//")
+
+  rbe_server_address = "unix:///tmp/reproxy.sock"
+
+  rbe_exec_strategy = "remote_local_fallback"
+
+  rbe_dial_timeout = "30s"
+
+  rbe_platform = "container-image=docker://gcr.io/cloud-marketplace/google/debian11@sha256:69e2789c9f3d28c6a0f13b25062c240ee7772be1f5e6d41bb4680b63eae6b304"
+
+  # TODO(zanderso): In the gn script, set the default value based on the host
+  # platform.
+  rbe_dir = rebase_path("//buildtools/linux-x64/reclient")
+}
diff --git a/build/toolchain/wasm.gni b/build/toolchain/wasm.gni
index 8fc0774ab3..859d063586 100644
--- a/build/toolchain/wasm.gni
+++ b/build/toolchain/wasm.gni
@@ -39,6 +39,7 @@ template("wasm_toolchain") {
     ar = "$compiler_prefix$emsdk_dir/upstream/emscripten/emar --em-config $em_config_path"
     cc = "$compiler_prefix$emsdk_dir/upstream/emscripten/emcc --em-config $em_config_path"
     cxx = "$compiler_prefix$emsdk_dir/upstream/emscripten/em++ --em-config $em_config_path"
+    asm = cc
 
     # emscripten emits this .worker.js file conditionally depending on whether
     # pthreads are on or not. Unfortunately, there is no way to conditionally