rustc: Add some stub metadata to each crate

src/comp/back/x86.rs

@@ -273,6 +273,16 @@ fn get_module_asm() -> str {
     ret _str.connect(glues, "\n\n");
 }
 
+fn get_meta_sect_name() -> str {
+    if (_str.eq(target_os(), "macos")) {
+        ret "__DATA,__note.rustc";
+    }
+    if (_str.eq(target_os(), "win32")) {
+        ret ".note.rustc";
+    }
+    ret ".note.rustc";
+}
+
 fn get_data_layout() -> str {
     if (_str.eq(target_os(), "macos")) {
       ret "e-p:32:32-f64:32:64-i64:32:64-f80:128:128-n8:16:32";

src/comp/middle/metadata.rs

@@ -0,0 +1,29 @@
+import std._str;
+import front.ast;
+import middle.trans;
+import back.x86;
+
+import lib.llvm.llvm;
+import lib.llvm.llvm.ValueRef;
+import lib.llvm.False;
+
+// Returns a Plain Old LLVM String.
+fn C_postr(str s) -> ValueRef {
+    ret llvm.LLVMConstString(_str.buf(s), _str.byte_len(s), False);
+}
+
+fn collect_meta_directives(@trans.crate_ctxt cx, @ast.crate crate)
+        -> ValueRef {
+    ret C_postr("Hello world!");    // TODO
+}
+
+fn write_metadata(@trans.crate_ctxt cx, @ast.crate crate) {
+    auto llmeta = collect_meta_directives(cx, crate);
+
+    auto llconst = trans.C_struct(vec(llmeta));
+    auto llglobal = llvm.LLVMAddGlobal(cx.llmod, trans.val_ty(llconst),
+                                       _str.buf("rust_metadata"));
+    llvm.LLVMSetInitializer(llglobal, llconst);
+    llvm.LLVMSetSection(llglobal, _str.buf(x86.get_meta_sect_name()));
+}
+

src/comp/middle/trans.rs

@@ -6192,6 +6192,9 @@ fn trans_crate(session.session sess, @ast.crate crate, str output,
         trans_main_fn(cx, cx.crate_ptr);
     }
 
+    // Translate the metadata.
+    middle.metadata.write_metadata(cx, crate);
+
     check_module(llmod);
 
     llvm.LLVMWriteBitcodeToFile(llmod, _str.buf(output));

src/comp/rustc.rc

@@ -14,6 +14,7 @@ mod front {
 
 mod middle {
     mod fold;
+    mod metadata;
     mod resolve;
     mod trans;
     mod ty;
@@ -40,6 +41,7 @@ mod util {
 }
 
 auth driver.rustc.main = impure;
+auth middle.metadata = unsafe;
 auth middle.trans = unsafe;
 auth middle.trans.copy_args_to_allocas = impure;
 auth middle.trans.trans_block = impure;