Merge pull request #12947 from brave/rust_flag_cleanup

clean up rustflags and clang toolchain paths

build/cargo.gni

@@ -89,27 +89,22 @@ template("cargo_build") {
   group_target = target_name
   cargo_build_target = target_name + "_cargo_build"
 
+  _rustflags = default_rustflags
+  if (defined(invoker.rustflags)) {
+    _rustflags += invoker.rustflags
+  }
+
   action(cargo_build_target) {
     script = "//brave/script/cargo.py"
 
     inputs = [ "//brave/script/cargo.py" ]
 
+    forward_variables_from(invoker, "*", [ "inputs" ])
+
     if (defined(invoker.inputs)) {
       inputs += invoker.inputs
     }
 
-    _rustflags = rustflags
-    if (defined(invoker.rustflags)) {
-      _rustflags += invoker.rustflags
-    }
-
-    forward_variables_from(invoker,
-                           "*",
-                           [
-                             "rustflags",
-                             "inputs",
-                           ])
-
     outputs = [ rust_lib_output_path ]
 
     if (!defined(target)) {
@@ -123,6 +118,7 @@ template("cargo_build") {
       "--target=" + target,
       "--toolchain=" +
           rustc_toolchain,  # defined by //brave/build/rust/config.gni,
+      "--clang_bin_path=" + rebase_path("$clang_base_path/bin"),
       "--is_debug=$is_debug",
       "--profile=$cargo_profile",
     ]

build/rust/BUILD.gn

@@ -27,6 +27,7 @@ cargo_build("rust_lib") {
     "//brave/components/skus/browser/rs:rust_lib",
     "//brave/components/speedreader/rust/lib",
   ]
+  rustflags = []
   if (enable_rust_bls) {
     rustflags += [ "--cfg=feature=\"enable_rust_bls\"" ]
     deps += [ "//brave/components/bls:rust_lib" ]

build/rust/config.gni

@@ -3,6 +3,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this file,
 # You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+import("//build/config/clang/clang.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/ios/config.gni")
 import("//build/config/rust.gni")
@@ -28,42 +29,50 @@ rustc_toolchain = ""
 cargo_lib_prefix = ""
 cargo_lib_suffix = ""
 
-# Rust compiler flags setup.
-# ---------------------------
-rustflags = [
-  # Overflow checks are optional in Rust, but even if switched
-  # off they do not cause undefined behavior (the overflowing
-  # behavior is defined). Because containers are bounds-checked
-  # in safe Rust, they also can't provoke buffer overflows.
-  # As such these checks may be less important in Rust than C++.
-  # But in (simplistic) testing they have negligible performance
-  # overhead, and this helps to provide consistent behavior
-  # between different configurations, so we'll keep them on until
-  # we discover a reason to turn them off.
-  "-Coverflow-checks=on",
-]
-
-if (use_lto_in_rustc_linking) {
-  rustflags += [ "-Clinker-plugin-lto" ]
+default_rustflags = [ "-Coverflow-checks=on" ]
+
+if (use_lld) {
+  default_rustflags += [
+    "-C",
+    "link-arg=-fuse-ld=lld",
+  ]
+
+  if (!is_win) {
+    default_rustflags += [
+      "-C",
+      "link-arg=-B" + rebase_path("$clang_base_path/bin"),
+    ]
+  }
 }
 
-if (use_lld && !is_component_build) {
-  rustflags += [ "-Cembed-bitcode=yes" ]
-  rustflags += [ "-Clto" ]
+# https://bugzilla.mozilla.org/show_bug.cgi?id=1188030#c14
+# Supposedly this bug was fixed, but it's still happening for us.
+too_many_personality_profiles_workaround = is_apple && use_lld && !is_component_build
+
+enable_rust_lto = too_many_personality_profiles_workaround
+
+if (enable_rust_lto) {
+  default_rustflags += [ "-Cembed-bitcode=yes" ]
+  default_rustflags += [ "-Clto" ]
 }
 
-if (optimize_for_size) {
-  rustflags += [ "-Copt-level=s" ]
+if (is_debug) {
+  if (too_many_personality_profiles_workaround) {
+    # must always be optimized for too_many_personality_profiles_workaround to work
+    default_rustflags += [ "-Copt-level=1" ]
+  } else {
+    default_rustflags += [ "-Copt-level=0" ]
+  }
+} else if (optimize_for_size) {
+  default_rustflags += [ "-Copt-level=s" ]
 } else {
-  rustflags += [ "-Copt-level=3" ]
+  default_rustflags += [ "-Copt-level=3" ]
 }
 
 if (symbol_level == 1) {
-  rustflags += [ "-Cdebuginfo=1" ]
-}
-
-if (symbol_level == 2) {
-  rustflags += [ "-g" ]
+  default_rustflags += [ "-Cdebuginfo=1" ]
+} else if (symbol_level == 2) {
+  default_rustflags += [ "-g" ]
 }
 
 # get links flags for rust lib
@@ -72,7 +81,7 @@ if (symbol_level == 2) {
 # See https://forge.rust-lang.org/release/platform-support.html for possible targets
 if (is_win) {
   if (current_cpu == "x86") {
-    rustflags += [ "--codegen target-feature=+crt-static" ]
+    default_rustflags += [ "--codegen target-feature=+crt-static" ]
     rustc_target = "i686-pc-windows-msvc"
   } else if (current_cpu == "x64") {
     rustc_target = "x86_64-pc-windows-msvc"
@@ -87,8 +96,8 @@ if (is_win) {
   if (current_cpu == "x64") {
     rustc_target = "x86_64-unknown-linux-gnu"
     if (use_sysroot) {
-      rustflags += [ "-C link-arg=--sysroot=$target_sysroot" ]
-      rustflags += [ "-C link-arg=-Wl,-rpath=\$ORIGIN" ]
+      default_rustflags += [ "-C link-arg=--sysroot=$target_sysroot" ]
+      default_rustflags += [ "-C link-arg=-Wl,-rpath=\$ORIGIN" ]
     }
   }
 } else if (is_android) {

script/cargo.py

@@ -34,8 +34,11 @@ def run_cargo(command, args):
         toolchains_path = os.path.abspath(
             os.path.join(rustup_path, 'toolchains', args.toolchain, "bin"))
         env['PATH'] = toolchains_path + os.pathsep + env['PATH']
-        llvm_ar = os.path.join(toolchains_path, 'llvm-ar')
-        env['AR'] = llvm_ar
+
+    if args.clang_bin_path is not None and not sys.platform.startswith('win'):
+        env['AR'] = os.path.join(args.clang_bin_path, 'llvm-ar')
+        env['CC'] = os.path.join(args.clang_bin_path, 'clang')
+        env['CXX'] = os.path.join(args.clang_bin_path, 'clang++')
 
     if args.mac_deployment_target is not None:
         env['MACOSX_DEPLOYMENT_TARGET'] = args.mac_deployment_target
@@ -102,6 +105,7 @@ def parse_args():
     parser.add_option('--toolchain')
     parser.add_option('--is_debug')
     parser.add_option('--profile')
+    parser.add_option('--clang_bin_path')
     parser.add_option('--mac_deployment_target')
     parser.add_option('--ios_deployment_target')
     parser.add_option("--rust_flag", action="append",