From 0c4bd1d8bb2863f16f13faad58eb3cbbcf7044cc Mon Sep 17 00:00:00 2001
From: User <user@example.com>
Date: Wed, 15 Jan 2025 11:49:31 +0000
Subject: [PATCH] codegen: add support for megadrive

---
 build_system/build_sysroot/Cargo.toml    |  8 +++-----
 src/base.rs                              | 17 +++++++++++++++++
 src/gcc_util.rs                          |  3 +--
 src/lib.rs                               |  1 +
 target_specs/m68k-unknown-linux-gnu.json | 12 ++++++------
 5 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/build_system/build_sysroot/Cargo.toml b/build_system/build_sysroot/Cargo.toml
index 2415207..8f928c5 100644
--- a/build_system/build_sysroot/Cargo.toml
+++ b/build_system/build_sysroot/Cargo.toml
@@ -6,11 +6,8 @@ resolver = "2"
 
 [dependencies]
 core = { path = "./sysroot_src/library/core" }
-compiler_builtins = "0.1"
+compiler_builtins = { version = "0.1", features = ["c"] }
 alloc = { path = "./sysroot_src/library/alloc" }
-std = { path = "./sysroot_src/library/std", features = ["panic_unwind", "backtrace"] }
-test = { path = "./sysroot_src/library/test" }
-proc_macro = { path = "./sysroot_src/library/proc_macro" }
 
 [patch.crates-io]
 rustc-std-workspace-core = { path = "./sysroot_src/library/rustc-std-workspace-core" }
@@ -35,4 +32,5 @@ codegen-units = 10000
 
 [profile.release]
 debug = "limited"
-#lto = "fat" # TODO(antoyo): re-enable when the failing LTO tests regarding proc-macros are fixed.
+panic = "abort"
+lto = "fat"
diff --git a/src/base.rs b/src/base.rs
index c9701fb..989f8aa 100644
--- a/src/base.rs
+++ b/src/base.rs
@@ -156,7 +156,24 @@ pub fn compile_codegen_unit(
         let target_cpu = gcc_util::target_cpu(tcx.sess);
         if target_cpu != "generic" {
             context.add_command_line_option(format!("-march={}", target_cpu));
+            context.add_command_line_option("-mcpu=68000");
         }
+            context.add_command_line_option("-flto");
+            context.add_driver_option("-flto");
+            //context.add_command_line_option("-fno-rtti");
+            context.add_driver_option("-fno-rtti");
+            context.add_command_line_option("-fno-exceptions");
+            context.add_driver_option("-fno-exceptions");
+
+            // Improve linker garbage collection
+            context.add_driver_option("-ffunction-sections");
+            context.add_command_line_option("-ffunction-sections");
+            context.add_driver_option("-fdata-sections");
+            context.add_command_line_option("-fdata-sections");
+
+            // ?
+            context.add_driver_option("-mxgot");
+            context.add_command_line_option("-mxgot");
 
         if tcx
             .sess
diff --git a/src/gcc_util.rs b/src/gcc_util.rs
index 560aff4..39b1889 100644
--- a/src/gcc_util.rs
+++ b/src/gcc_util.rs
@@ -242,8 +242,7 @@ pub fn to_gcc_features<'a>(sess: &Session, s: &'a str) -> SmallVec<[&'a str; 2]>
 
 fn arch_to_gcc(name: &str) -> &str {
     match name {
-        "M68020" => "68020",
-        _ => name,
+        _ => "68000",
     }
 }
 
diff --git a/src/lib.rs b/src/lib.rs
index f6ad0c7..e19dbcf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -196,6 +196,7 @@ impl CodegenBackend for GccCodegenBackend {
             let context = Context::default();
             if target_cpu != "generic" {
                 context.add_command_line_option(format!("-march={}", target_cpu));
+                context.add_command_line_option("-mcpu=68000");
             }
 
             **self.target_info.info.lock().expect("lock") = context.get_target_info();
diff --git a/target_specs/m68k-unknown-linux-gnu.json b/target_specs/m68k-unknown-linux-gnu.json
index 95ea061..d1ff9a2 100644
--- a/target_specs/m68k-unknown-linux-gnu.json
+++ b/target_specs/m68k-unknown-linux-gnu.json
@@ -1,17 +1,17 @@
 {
   "arch": "m68k",
-  "cpu": "M68020",
+  "cpu": "M68000",
   "crt-static-respected": true,
   "data-layout": "E-m:e-p:32:16:32-i8:8:8-i16:16:16-i32:16:32-n8:16:32-a:0:16-S16",
-  "dynamic-linking": true,
+  "dynamic-linking": false,
   "env": "gnu",
   "has-rpath": true,
-  "has-thread-local": true,
-  "llvm-target": "m68k-unknown-linux-gnu",
+  "has-thread-local": false,
+  "llvm-target": "m68k-elf",
   "max-atomic-width": 32,
   "os": "linux",
-  "position-independent-executables": true,
-  "relro-level": "full",
+  "position-independent-executables": false,
+  "relro-level": "none",
   "supported-split-debuginfo": [
     "packed",
     "unpacked",
-- 
2.34.1