rustc: Don't emit metadata for default and GC box addrspaces.

Author: Elliott Slaughter

src/rustc/middle/trans/base.rs

@@ -659,14 +659,16 @@ fn emit_tydescs(ccx: @crate_ctxt) {
         lib::llvm::SetLinkage(gvar, lib::llvm::InternalLinkage);
 
         // Index tydesc by addrspace.
-        let llty = T_ptr(ccx.tydesc_type);
-        let addrspace_name = #fmt("_gc_addrspace_metadata_%u",
-                                  ti.addrspace as uint);
-        let addrspace_gvar = str::as_c_str(addrspace_name, |buf| {
-            llvm::LLVMAddGlobal(ccx.llmod, llty, buf)
-        });
-        lib::llvm::SetLinkage(addrspace_gvar, lib::llvm::InternalLinkage);
-        llvm::LLVMSetInitializer(addrspace_gvar, gvar);
+        if ti.addrspace > gc_box_addrspace {
+            let llty = T_ptr(ccx.tydesc_type);
+            let addrspace_name = #fmt("_gc_addrspace_metadata_%u",
+                                      ti.addrspace as uint);
+            let addrspace_gvar = str::as_c_str(addrspace_name, |buf| {
+                llvm::LLVMAddGlobal(ccx.llmod, llty, buf)
+            });
+            lib::llvm::SetLinkage(addrspace_gvar, lib::llvm::InternalLinkage);
+            llvm::LLVMSetInitializer(addrspace_gvar, gvar);
+        }
     };
 }