change expect() to unwrap_or_else() and update msg

Author: mj10021

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -331,7 +331,7 @@ pub(crate) fn print(req: PrintRequest, sess: &Session) {
     match req {
         PrintRequest::TargetCPUs => {
             let cpu_cstring = CString::new(handle_native(sess.target.cpu.as_ref()))
-                .expect("failed to convert to cstring");
+                .unwrap_or_else(|e| bug!("failed to convert to cstring: {}", e));
             unsafe { llvm::LLVMRustPrintTargetCPUs(tm, cpu_cstring.as_ptr()) };
         }
         PrintRequest::TargetFeatures => print_target_features(sess, tm),

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -324,10 +324,14 @@ extern "C" void LLVMRustPrintTargetCPUs(LLVMTargetMachineRef TM, const char* Tar
       MaxCPULen, "native", (int)HostCPU.size(), HostCPU.data());
   }
   for (auto &CPU : CPUTable) {
-    printf("    %-*s", MaxCPULen, CPU.Key);
     // Compare cpu against current target to label the default
     if (strcmp(CPU.Key, TargetCPU) == 0) {
-      printf("   - this is the default target cpu for the current target");
+      printf("    %-*s - This is the default target CPU"
+      " for the current build target (currently %s).",
+        MaxCPULen, CPU.Key, Target->getTargetTriple().str().c_str());
+    }
+    else {
+      printf("    %-*s", MaxCPULen, CPU.Key);
     }
     printf("\n");
   }