Linux arm64 support (#6927)

* linux arm64 support

DEPS

@@ -39,10 +39,17 @@ hooks = [
     'action': ['vpython3', 'script/download_rust_deps.py', '--platform', 'ios'],
   },
   {
-    # Download rust deps if necessary for Linux, macOS, Windows
+    # Download rust deps if necessary for Linux
     'name': 'download_rust_deps',
     'pattern': '.',
-    'condition': 'not checkout_android and not checkout_ios',
+    'condition': 'checkout_linux',
+    'action': ['vpython3', 'script/download_rust_deps.py', '--platform', 'linux'],
+  },
+  {
+    # Download rust deps if necessary for the other platforms (macOS and Windows)
+    'name': 'download_rust_deps',
+    'pattern': '.',
+    'condition': 'not checkout_android and not checkout_ios and not checkout_linux',
     'action': ['vpython3', 'script/download_rust_deps.py'],
   },
   {

build/rust/config.gni

@@ -32,6 +32,14 @@ if (is_win) {
       rust_flags += " -C link-arg=--sysroot=$target_sysroot "
       rust_flags += " -C link-arg=-Wl,-rpath=\$ORIGIN "
     }
+  } else if (current_cpu == "arm64") {
+    rustc_target = "aarch64-unknown-linux-gnu"
+    rustc_toolchain = "arm64"
+    rust_flags += " -C linker=aarch64-linux-gnu-gcc "
+    if (use_sysroot) {
+      rust_flags += " -C link-arg=--sysroot=$target_sysroot "
+      rust_flags += " -C link-arg=-Wl,-rpath=\$ORIGIN "
+    }
   }
 } else if (is_android) {
   if (current_cpu == "arm") {

script/download_rust_deps.py

@@ -124,6 +124,29 @@ def make_standalone_toolchain_for_android():
     fp.close()
 
 
+def get_linux_target(target_arch):
+    return {
+        'arm64': 'aarch64-linux',
+        'x86_64': 'x86_64-linux',
+    }[target_arch]
+
+
+def get_linux_linker(target_arch):
+    return get_linux_target(target_arch) + "-gnu-gcc"
+
+
+def make_rustup_config_for_linux():
+    config_path = os.path.join(RUSTUP_HOME, 'config')
+    fp = open(config_path, "w+")
+
+    for target_arch in ['arm64', 'x86_64']:
+        # Add target to rustup config
+        fp.write("[target." + get_linux_target(target_arch) + "]\r\n")
+        fp.write("linker = \"" + get_linux_linker(target_arch) + "\"\r\n")
+
+    fp.close()
+
+
 def parse_args():
     parser = argparse.ArgumentParser(description='Download rust deps')
 
@@ -171,6 +194,8 @@ def main():
 
     if args.platform == 'android':
         make_standalone_toolchain_for_android()
+    elif args.platform == 'linux':
+        make_rustup_config_for_linux()
 
     tools = [
         {