Uplift of #12774 (squashed) to beta

build/commands/lib/config.js

@@ -470,9 +470,7 @@ Config.prototype.buildArgs = function () {
       args.target_environment = this.targetEnvironment
     }
     args.enable_dsyms = true
-    args.enable_stripping = !this.isDebug()
-    args.use_clang_coverage = false
-    args.use_lld = false
+    args.enable_stripping = !this.isComponentBuild()
     // Component builds are not supported for iOS:
     // https://chromium.googlesource.com/chromium/src/+/master/docs/component_build.md
     args.is_component_build = false
@@ -481,7 +479,7 @@ Config.prototype.buildArgs = function () {
     // DCHECK's crash on Static builds without allowing the debugger to continue
     // Can be removed when approprioate DCHECK's have been fixed:
     // https://github.com/brave/brave-browser/issues/10334
-    args.dcheck_always_on = this.isDebug()
+    args.dcheck_always_on = this.isComponentBuild()
 
     args.ios_enable_content_widget_extension = false
     args.ios_enable_search_widget_extension = false

build/rust/config.gni

@@ -47,7 +47,7 @@ if (use_lto_in_rustc_linking) {
   rustflags += [ "-Clinker-plugin-lto" ]
 }
 
-if (!is_ios && !is_debug) {
+if (use_lld && !is_debug) {
   rustflags += [ "-Cembed-bitcode=yes" ]
   rustflags += [ "-Clto" ]
 }

ios/BUILD.gn

@@ -13,6 +13,11 @@ import("//brave/ios/browser/api/url/headers.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/ios/rules.gni")
 
+# lld is required when building arm64 with optimization in order to avoid
+# runtime crashes
+assert(is_debug || current_cpu != "arm64" || use_lld,
+       "Optimized arm64 iOS builds require lld")
+
 config("internal_config") {
   visibility = [ ":*" ]
   ldflags =