From 14662a66dc6369ffc53148a6cd1f6406194b082b Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Thu, 23 Sep 2021 21:30:13 +0800
Subject: [PATCH] nac3embedded: run linker (WIP)

---
 nac3embedded/kernel.ld  | 53 +++++++++++++++++++++++++++++++++++++++++
 nac3embedded/src/lib.rs | 14 +++++++++--
 shell.nix               |  9 ++++++-
 3 files changed, 73 insertions(+), 3 deletions(-)
 create mode 100644 nac3embedded/kernel.ld

diff --git a/nac3embedded/kernel.ld b/nac3embedded/kernel.ld
new file mode 100644
index 00000000..6523d631
--- /dev/null
+++ b/nac3embedded/kernel.ld
@@ -0,0 +1,53 @@
+/* Force ld to make the ELF header as loadable. */
+PHDRS
+{
+    headers     PT_LOAD FILEHDR PHDRS ;
+    text        PT_LOAD ;
+    data        PT_LOAD ;
+    dynamic     PT_DYNAMIC ;
+    eh_frame    PT_GNU_EH_FRAME ;
+}
+
+SECTIONS
+{
+    /* Push back .text section enough so that ld.lld not complain */
+    . = SIZEOF_HEADERS;
+
+    .text :
+    {
+        *(.text .text.*)
+    } : text
+
+    .rodata :
+    {
+        *(.rodata .rodata.*)
+    }
+
+    .eh_frame :
+    {
+        KEEP(*(.eh_frame))
+    } : text
+
+    .eh_frame_hdr :
+    {
+        KEEP(*(.eh_frame_hdr))
+    } : text : eh_frame
+
+    .data :
+    {
+        *(.data)
+    } : data
+
+    .dynamic :
+    {
+        *(.dynamic)
+    } : data : dynamic
+
+    .bss (NOLOAD) : ALIGN(4)
+    {
+        __bss_start = .;
+        *(.sbss .sbss.* .bss .bss.*);
+        . = ALIGN(4);
+        _end = .;
+    }
+}
diff --git a/nac3embedded/src/lib.rs b/nac3embedded/src/lib.rs
index 3ee1ef72..fbbb66b4 100644
--- a/nac3embedded/src/lib.rs
+++ b/nac3embedded/src/lib.rs
@@ -1,6 +1,7 @@
 use std::collections::HashMap;
 use std::sync::Arc;
 use std::path::Path;
+use std::process::Command;
 
 use pyo3::prelude::*;
 use pyo3::exceptions;
@@ -163,11 +164,20 @@ impl Nac3 {
                 .write_to_file(module, FileType::Object, Path::new(&format!("{}.o", module.get_name().to_str().unwrap())))
                 .expect("couldn't write module to file");
         })));
-        let threads: Vec<String> = (0..4).map(|i| format!("module{}", i)).collect();
-        let threads: Vec<_> = threads.iter().map(|s| s.as_str()).collect();
+        let thread_names: Vec<String> = (0..4).map(|i| format!("module{}", i)).collect();
+        let threads: Vec<_> = thread_names.iter().map(|s| s.as_str()).collect();
         let (registry, handles) = WorkerRegistry::create_workers(&threads, top_level.clone(), f);
         registry.add_task(task);
         registry.wait_tasks_complete(handles);
+
+        if let Ok(linker_status) = Command::new("ld.lld").args(&["-shared", "--eh-frame-hdr", "-Tkernel.ld"]).status() {
+            if !linker_status.success() {
+                return Err(exceptions::PyRuntimeError::new_err("failed to start linker"));
+            }
+        } else {
+            return Err(exceptions::PyRuntimeError::new_err("linker returned non-zero status code"));
+        }
+
         Ok(())
     }
 }
diff --git a/shell.nix b/shell.nix
index 35be2055..070196c7 100644
--- a/shell.nix
+++ b/shell.nix
@@ -4,6 +4,13 @@ in
   pkgs.stdenv.mkDerivation {
     name = "nac3-env";
     buildInputs = with pkgs; [
-      llvm_11 clang_11 cargo rustc libffi libxml2 clippy
+      llvm_11
+      clang_11
+      lld_11
+      cargo
+      rustc
+      libffi
+      libxml2
+      clippy
     ];
   }