Implement printing to file in llvm_util

Author: dtolnay

compiler/rustc_codegen_llvm/src/lib.rs

@@ -320,7 +320,7 @@ impl CodegenBackend for LlvmCodegenBackend {
 "#
                 );
             }
-            req => llvm_util::print(req, sess),
+            req => llvm_util::print(req, out, sess),
         }
     }
 

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -8,6 +8,7 @@ use libc::c_int;
 use rustc_codegen_ssa::target_features::{
     supported_target_features, tied_target_features, RUSTC_SPECIFIC_FEATURES,
 };
+use rustc_codegen_ssa::traits::PrintBackendInfo;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_data_structures::small_c_str::SmallCStr;
 use rustc_fs_util::path_to_c_string;
@@ -350,7 +351,7 @@ fn llvm_target_features(tm: &llvm::TargetMachine) -> Vec<(&str, &str)> {
     ret
 }
 
-fn print_target_features(sess: &Session, tm: &llvm::TargetMachine) {
+fn print_target_features(out: &mut dyn PrintBackendInfo, sess: &Session, tm: &llvm::TargetMachine) {
     let mut llvm_target_features = llvm_target_features(tm);
     let mut known_llvm_target_features = FxHashSet::<&'static str>::default();
     let mut rustc_target_features = supported_target_features(sess)
@@ -383,24 +384,24 @@ fn print_target_features(sess: &Session, tm: &llvm::TargetMachine) {
         .max()
         .unwrap_or(0);
 
-    println!("Features supported by rustc for this target:");
+    writeln!(out, "Features supported by rustc for this target:");
     for (feature, desc) in &rustc_target_features {
-        println!("    {1:0$} - {2}.", max_feature_len, feature, desc);
+        writeln!(out, "    {1:0$} - {2}.", max_feature_len, feature, desc);
     }
-    println!("\nCode-generation features supported by LLVM for this target:");
+    writeln!(out, "\nCode-generation features supported by LLVM for this target:");
     for (feature, desc) in &llvm_target_features {
-        println!("    {1:0$} - {2}.", max_feature_len, feature, desc);
+        writeln!(out, "    {1:0$} - {2}.", max_feature_len, feature, desc);
     }
     if llvm_target_features.is_empty() {
-        println!("    Target features listing is not supported by this LLVM version.");
+        writeln!(out, "    Target features listing is not supported by this LLVM version.");
     }
-    println!("\nUse +feature to enable a feature, or -feature to disable it.");
-    println!("For example, rustc -C target-cpu=mycpu -C target-feature=+feature1,-feature2\n");
-    println!("Code-generation features cannot be used in cfg or #[target_feature],");
-    println!("and may be renamed or removed in a future version of LLVM or rustc.\n");
+    writeln!(out, "\nUse +feature to enable a feature, or -feature to disable it.");
+    writeln!(out, "For example, rustc -C target-cpu=mycpu -C target-feature=+feature1,-feature2\n");
+    writeln!(out, "Code-generation features cannot be used in cfg or #[target_feature],");
+    writeln!(out, "and may be renamed or removed in a future version of LLVM or rustc.\n");
 }
 
-pub(crate) fn print(req: PrintRequest, sess: &Session) {
+pub(crate) fn print(req: PrintRequest, out: &mut dyn PrintBackendInfo, sess: &Session) {
     require_inited();
     let tm = create_informational_target_machine(sess);
     match req {
@@ -412,7 +413,7 @@ pub(crate) fn print(req: PrintRequest, sess: &Session) {
                 .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),
+        PrintRequest::TargetFeatures => print_target_features(out, sess, tm),
         _ => bug!("rustc_codegen_llvm can't handle print request: {:?}", req),
     }
 }