From 8436fbf30fd66c87d6e2cece6e57a88e217ad1dc Mon Sep 17 00:00:00 2001
From: klzgrad <kizdiv@gmail.com>
Date: Tue, 19 May 2020 23:42:14 +0800
Subject: [PATCH] build: Support -mcpu= on ARM and ARM64

---
 src/build/config/arm.gni           | 5 +++++
 src/build/config/compiler/BUILD.gn | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/src/build/config/arm.gni b/src/build/config/arm.gni
index 410d3cb8f9..08e68d3fbe 100644
--- a/src/build/config/arm.gni
+++ b/src/build/config/arm.gni
@@ -36,6 +36,8 @@ if (current_cpu == "arm" || v8_current_cpu == "arm") {
     # Thumb is a reduced instruction set available on some ARM processors that
     # has increased code density.
     arm_use_thumb = true
+
+    arm_cpu = ""
   }
 
   if (current_os == "android" || target_os == "android") {
@@ -124,6 +126,9 @@ if (current_cpu == "arm" || v8_current_cpu == "arm") {
   # arm64 supports only "hard".
   arm_float_abi = "hard"
   arm_use_neon = true
+  declare_args() {
+    arm_cpu = ""
+  }
   declare_args() {
     # Enables the new Armv8 branch protection features. Valid strings are:
     # - "pac": Enables Pointer Authentication Code (PAC, featured in Armv8.3)
diff --git a/src/build/config/compiler/BUILD.gn b/src/build/config/compiler/BUILD.gn
index e03223d56b..5ed631b71b 100644
--- a/src/build/config/compiler/BUILD.gn
+++ b/src/build/config/compiler/BUILD.gn
@@ -926,6 +926,10 @@ config("compiler_cpu_abi") {
           "-march=$arm_arch",
           "-mfloat-abi=$arm_float_abi",
         ]
+        if (arm_cpu != "") {
+          cflags += [ "-mcpu=$arm_cpu" ]
+        }
+        ldflags += [ "-mfloat-abi=$arm_float_abi" ]
       }
       if (arm_tune != "") {
         cflags += [ "-mtune=$arm_tune" ]
@@ -939,6 +943,9 @@ config("compiler_cpu_abi") {
         # Outline atomics crash on Exynos 9810. http://crbug.com/1272795
         cflags += [ "-mno-outline-atomics" ]
       }
+      if (arm_cpu != "") {
+        cflags += [ "-mcpu=$arm_cpu" ]
+      }
     } else if (current_cpu == "mipsel" && !is_nacl) {
       ldflags += [ "-Wl,--hash-style=sysv" ]
       if (custom_toolchain == "") {