Adding GC: MMTk tag to Julia's banner when building with MMTk (mmtk…

…#193)

Merge with mmtk/julia#72.

Should add info to Julia's banner about the version of MMTk used in the
build such as:

```
               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.12.0-DEV.955 (2024-11-26)
 _/ |\__'_|_|_|\__'_|  |  adding-tag-to-banner/0ccc307863* (fork: 101 commits, 134 days)
|__/                   |  Built with MMTk Julia 0.1.0 (a775934-dirty), using MMTk 0.27.0 (de10fa4, DEFAULT, IMMIX_NON_MOVING, IMMIX_SMALLER_BLOCK, OBJECT_PINNING, VM_SPACE)
```

mmtk/Cargo.toml

@@ -18,7 +18,7 @@ crate-type = ["cdylib"]
 
 [build-dependencies]
 cc = "*"
-built = "*"
+built = { version = "*", features = ["git2"] }
 bindgen = "*"
 
 [profile.release]

mmtk/api/mmtk.h

@@ -50,6 +50,7 @@ extern void mmtk_runtime_panic(void);
 extern void mmtk_unreachable(void);
 extern unsigned char mmtk_pin_object(void* obj);
 extern bool mmtk_is_pinned(void* obj);
+extern const char* get_mmtk_version(void);
 
 extern void mmtk_set_vm_space(void* addr, size_t size);
 extern void mmtk_immortal_region_post_alloc(void* addr, size_t size);

mmtk/build.rs

@@ -67,4 +67,6 @@ fn main() {
     bindings
         .write_to_file("src/julia_types.rs")
         .expect("Couldn't write bindings!");
+
+    built::write_built_file().expect("Failed to acquire build-time information");
 }

mmtk/src/api.rs

@@ -504,3 +504,10 @@ pub extern "C" fn mmtk_unpin_object(_object: ObjectReference) -> bool {
 pub extern "C" fn mmtk_is_pinned(_object: ObjectReference) -> bool {
     false
 }
+
+#[no_mangle]
+pub extern "C" fn get_mmtk_version() -> *const c_char {
+    crate::build_info::MMTK_JULIA_FULL_VERSION_STRING
+        .as_c_str()
+        .as_ptr() as _
+}

mmtk/src/build_info.rs

@@ -0,0 +1,18 @@
+use std::ffi::CString;
+
+mod raw {
+    // The include imports a full list of the constants in built.rs from https://docs.rs/built/latest/built/index.html
+    include!(concat!(env!("OUT_DIR"), "/built.rs"));
+}
+
+lazy_static! {
+    // Owned string for the binding version, such as MMTk Julia 0.14.0 (cfc755f-dirty)
+    static ref BINDING_VERSION_STRING: String = match (raw::GIT_COMMIT_HASH, raw::GIT_DIRTY) {
+        (Some(hash), Some(dirty)) => format!("Built with MMTk Julia {} ({}{})", raw::PKG_VERSION, hash.split_at(7).0, if dirty { "-dirty" } else { "" }),
+        (Some(hash), None) => format!("Built with MMTk Julia {} ({}{})", raw::PKG_VERSION, hash.split_at(7).0, "-?"),
+        _ => format!("Built with MMTk Julia {}", raw::PKG_VERSION),
+    };
+    // Owned string for both binding and core version.
+    #[derive(Debug)]
+    pub static ref MMTK_JULIA_FULL_VERSION_STRING: CString = CString::new(format!("{}, using {}", *BINDING_VERSION_STRING, *mmtk::build_info::MMTK_FULL_BUILD_INFO)).unwrap();
+}

mmtk/src/lib.rs

@@ -17,6 +17,7 @@ use std::sync::{Arc, Condvar, Mutex, RwLock};
 
 pub mod active_plan;
 pub mod api;
+mod build_info;
 pub mod collection;
 pub mod object_model;
 pub mod reference_glue;