[WIP] Strip debug symbols from kernel

Author: phil-opp

Diff for: build.rs

@@ -40,7 +40,9 @@ fn main() {
         .expect("KERNEL has no valid file name")
         .to_str()
         .expect("kernel file name not valid utf8");
-    let kernel_file_name_replaced = kernel_file_name.replace('-', "_");
+    let kernel_stripped_file_name = format!("kernel_stripped-{}", kernel_file_name);
+    let kernel_stripped_file_name_replaced = kernel_stripped_file_name.replace('-', "_");
+    let kernel_stripped_out_path = out_dir.join(&kernel_stripped_file_name);
     let kernel_out_path = out_dir.join(format!("kernel_bin-{}.o", kernel_file_name));
     let kernel_archive_path = out_dir.join(format!("libkernel_bin-{}.a", kernel_file_name));
 
@@ -76,29 +78,40 @@ fn main() {
             Kernel executable at `{}`\n", kernel.display());
     }
 
-    // wrap the kernel executable as binary in a new ELF file
+    // strip debug symbols from kernel for faster loading
     let objcopy = llvm_tools
         .tool(&llvm_tools::exe("llvm-objcopy"))
         .expect("llvm-objcopy not found in llvm-tools");
-    let mut cmd = Command::new(objcopy);
+    let mut cmd = Command::new(&objcopy);
+    cmd.arg("--strip-debug");
+    cmd.arg(&kernel);
+    cmd.arg(&kernel_stripped_out_path);
+    let exit_status = cmd.status().expect("failed to run objcopy to strip debug symbols");
+    if !exit_status.success() {
+        eprintln!("Error: Stripping debug symbols failed");
+        process::exit(1);
+    }
+
+    // wrap the kernel executable as binary in a new ELF file
+    let mut cmd = Command::new(&objcopy);
     cmd.arg("-I").arg("binary");
     cmd.arg("-O").arg("elf64-x86-64");
     cmd.arg("--binary-architecture=i386:x86-64");
     cmd.arg("--rename-section").arg(".data=.kernel");
     cmd.arg("--redefine-sym").arg(format!(
         "_binary_{}_start=_kernel_start_addr",
-        kernel_file_name_replaced
+        kernel_stripped_file_name_replaced
     ));
     cmd.arg("--redefine-sym").arg(format!(
         "_binary_{}_end=_kernel_end_addr",
-        kernel_file_name_replaced
+        kernel_stripped_file_name_replaced
     ));
     cmd.arg("--redefine-sym").arg(format!(
         "_binary_{}_size=_kernel_size",
-        kernel_file_name_replaced
+        kernel_stripped_file_name_replaced
     ));
-    cmd.current_dir(kernel.parent().expect("KERNEL has no valid parent dir"));
-    cmd.arg(&kernel_file_name);
+    cmd.current_dir(&out_dir);
+    cmd.arg(&kernel_stripped_file_name);
     cmd.arg(&kernel_out_path);
     let exit_status = cmd.status().expect("failed to run objcopy");
     if !exit_status.success() {