--- build/config/compiler/BUILD.gn.orig	2026-07-07 05:57:56 UTC
+++ build/config/compiler/BUILD.gn
@@ -203,7 +203,7 @@ declare_args() {
   # This greatly reduces the size of debug builds, at the cost of
   # debugging information which is required by some specialized
   # debugging tools.
-  simple_template_names = is_clang && !is_win && !is_apple
+  simple_template_names = is_clang && !is_win && !is_apple && !is_bsd
 
   # This switch is used to enable -Wexit-time-destructors by default. This
   # warning serves as a flip switch to allow a gradual migration of targets
@@ -284,7 +284,7 @@ assert(is_bot ||
 #
 # Since this is referenced both when passing the file and when deciding which
 # warnings to enable, store it in a separate variable here.
-use_clang_warning_suppression_file =
+use_clang_warning_suppression_file = !is_bsd &&
     is_clang && clang_warning_suppression_file != ""
 
 # default_include_dirs ---------------------------------------------------------
@@ -302,13 +302,16 @@ config("no_unresolved_symbols") {
 # Compiler instrumentation can introduce dependencies in DSOs to symbols in
 # the executable they are loaded into, so they are unresolved at link-time.
 config("no_unresolved_symbols") {
-  if (!using_sanitizer &&
+  if (!using_sanitizer && !is_bsd &&
       (is_linux || is_chromeos || is_android || is_fuchsia)) {
     ldflags = [
       "-Wl,-z,defs",
       "-Wl,--as-needed",
     ]
   }
+  if (current_cpu == "x86" && is_openbsd) {
+    ldflags = [ "-Wl,-z,notext", "-Wl,--strip-all" ]
+  }
 }
 
 # compiler ---------------------------------------------------------------------
@@ -541,6 +544,10 @@ config("compiler") {
     }
   }
 
+  if (is_openbsd) {
+    ldflags += [ "-Wl,-z,wxneeded" ]
+  }
+
   # Linux-specific compiler flags setup.
   # ------------------------------------
   if (is_linux || is_chromeos) {
@@ -576,9 +583,9 @@ config("compiler") {
   if (is_clang) {
     # Flags for diagnostics.
     cflags += [ "-fcolor-diagnostics" ]
-    if (!is_win) {
+    if (!is_win && !is_bsd) {
       cflags += [ "-fdiagnostics-show-inlining-chain" ]
-    } else {
+    } else if (!is_bsd) {
       # Combine after https://github.com/llvm/llvm-project/pull/192241
       cflags += [ "/clang:-fdiagnostics-show-inlining-chain" ]
     }
@@ -603,7 +610,7 @@ config("compiler") {
     }
   }
 
-  if (is_clang) {
+  if (is_clang && !is_bsd) {
     cflags += [ "-fcrash-diagnostics-dir=" + clang_diagnostic_dir ]
     if (save_reproducers_on_lld_crash && use_lld) {
       ldflags += [
@@ -1468,7 +1475,7 @@ config("clang_revision") {
 }
 
 config("clang_revision") {
-  if (is_clang && clang_base_path == default_clang_base_path &&
+  if (is_clang && !is_bsd && clang_base_path == default_clang_base_path &&
       current_os != "zos") {
     _perform_consistency_checks = current_toolchain == default_toolchain
     if (llvm_force_head_revision) {
@@ -1582,7 +1589,7 @@ ubsan_hardening("c_array_bounds") {
 # See also: https://crbug.com/40891132#comment10
 ubsan_hardening("c_array_bounds") {
   sanitizer = "array-bounds"
-  condition = !(is_asan && target_cpu == "x86")
+  condition = !(is_bsd || (is_asan && target_cpu == "x86"))
 
   # Because we've enabled array-bounds sanitizing we also want to suppress
   # the related warning about "unsafe-buffer-usage-in-static-sized-array",
@@ -1596,6 +1603,7 @@ ubsan_hardening("return") {
 # `NOTREACHED()` at the end of such functions.
 ubsan_hardening("return") {
   sanitizer = "return"
+  condition = !is_bsd
 }
 
 config("rustc_revision") {
@@ -1930,9 +1938,6 @@ config("default_warnings") {
 
       # TODO(crbug.com/432275627): Fix and re-enable.
       "-Wno-uninitialized-const-pointer",
-
-      # TODO(crbug.com/495753203): Fix and re-enable.
-      "-Wno-unused-but-set-global",
     ]
 
     cflags_cc += [
@@ -2746,7 +2751,7 @@ config("afdo") {
 # There are some targeted places that AFDO regresses, so we provide a separate
 # config to allow AFDO to be disabled per-target.
 config("afdo") {
-  if (is_clang) {
+  if (is_clang && !is_bsd) {
     cflags = []
     if (clang_emit_debug_info_for_profiling) {
       # Add the following flags to generate debug info for profiling.
@@ -2773,7 +2778,7 @@ config("afdo") {
       cflags += [ "-Wno-backend-plugin" ]
       inputs = [ _clang_sample_profile ]
     }
-  } else if (auto_profile_path != "" && is_a_target_toolchain) {
+  } else if (auto_profile_path != "" && is_a_target_toolchain && !is_bsd) {
     cflags = [ "-fauto-profile=${auto_profile_path}" ]
     inputs = [ auto_profile_path ]
   }