Use informational target machine for metadata

Since there is nothing to optimise there...

src/librustc_codegen_llvm/lib.rs

@@ -23,7 +23,7 @@
 #![deny(rust_2018_idioms)]
 #![allow(explicit_outlives_requirements)]
 
-use back::write::create_target_machine;
+use back::write::{create_target_machine, create_informational_target_machine};
 use syntax_pos::symbol::Symbol;
 
 extern crate flate2;
@@ -112,8 +112,9 @@ pub struct LlvmCodegenBackend(());
 
 impl ExtraBackendMethods for LlvmCodegenBackend {
     fn new_metadata(&self, tcx: TyCtxt<'_, '_, '_>, mod_name: &str) -> ModuleLlvm {
-        ModuleLlvm::new(tcx, mod_name)
+        ModuleLlvm::new_metadata(tcx, mod_name)
     }
+
     fn write_metadata<'b, 'gcx>(
         &self,
         tcx: TyCtxt<'b, 'gcx, 'gcx>,
@@ -363,7 +364,6 @@ impl ModuleLlvm {
         unsafe {
             let llcx = llvm::LLVMRustContextCreate(tcx.sess.fewer_names());
             let llmod_raw = context::create_module(tcx, llcx, mod_name) as *const _;
-
             ModuleLlvm {
                 llmod_raw,
                 llcx,
@@ -372,6 +372,18 @@ impl ModuleLlvm {
         }
     }
 
+    fn new_metadata(tcx: TyCtxt<'_, '_, '_>, mod_name: &str) -> Self {
+        unsafe {
+            let llcx = llvm::LLVMRustContextCreate(tcx.sess.fewer_names());
+            let llmod_raw = context::create_module(tcx, llcx, mod_name) as *const _;
+            ModuleLlvm {
+                llmod_raw,
+                llcx,
+                tm: create_informational_target_machine(&tcx.sess, false),
+            }
+        }
+    }
+
     fn parse(
         cgcx: &CodegenContext<LlvmCodegenBackend>,
         name: &str,