Search other library paths when loking for link objects

src/librustc_codegen_llvm/back/link.rs

@@ -457,6 +457,21 @@ fn print_native_static_libs(sess: &Session, all_native_libs: &[NativeLibrary]) {
     }
 }
 
+fn get_file_path(sess: &Session, name: &str) -> PathBuf {
+    let fs = sess.target_filesearch(PathKind::Native);
+    let file_path = fs.get_lib_path().join(name);
+    if file_path.exists() {
+        return file_path
+    }
+    for search_path in fs.search_paths() {
+        let file_path = search_path.dir.join(name);
+        if file_path.exists() {
+            return file_path
+        }
+    }
+    PathBuf::from(name)
+}
+
 // Create a dynamic library or executable
 //
 // This will invoke the system linker/cc to create the resulting file. This
@@ -472,7 +487,6 @@ fn link_natively(sess: &Session,
     // The invocations of cc share some flags across platforms
     let (pname, mut cmd) = get_linker(sess, &linker, flavor);
 
-    let root = sess.target_filesearch(PathKind::Native).get_lib_path();
     if let Some(args) = sess.target.target.options.pre_link_args.get(&flavor) {
         cmd.args(args);
     }
@@ -500,12 +514,12 @@ fn link_natively(sess: &Session,
         &sess.target.target.options.pre_link_objects_dll
     };
     for obj in pre_link_objects {
-        cmd.arg(root.join(obj));
+        cmd.arg(get_file_path(sess, obj));
     }
 
     if crate_type == config::CrateType::Executable && sess.crt_static() {
         for obj in &sess.target.target.options.pre_link_objects_exe_crt {
-            cmd.arg(root.join(obj));
+            cmd.arg(get_file_path(sess, obj));
         }
     }
 
@@ -529,11 +543,11 @@ fn link_natively(sess: &Session,
         cmd.args(args);
     }
     for obj in &sess.target.target.options.post_link_objects {
-        cmd.arg(root.join(obj));
+        cmd.arg(get_file_path(sess, obj));
     }
     if sess.crt_static() {
         for obj in &sess.target.target.options.post_link_objects_crt {
-            cmd.arg(root.join(obj));
+            cmd.arg(get_file_path(sess, obj));
         }
     }
     if let Some(args) = sess.target.target.options.post_link_args.get(&flavor) {

src/test/run-make-fulldeps/libs-search-path/Makefile

@@ -0,0 +1,16 @@
+-include ../tools.mk
+
+ifeq ($(if $(IS_WINDOWS),$(IS_MSVC),no),)
+
+all: empty.rs
+	cp -r $(shell cygpath -u $(shell $(RUSTC) --print sysroot)) $(TMPDIR)/sysroot
+	$(RUSTC) --target $(TARGET) --sysroot $(TMPDIR)/sysroot -L$(TMPDIR)/obj -Z print-link-args empty.rs | $(CGREP) 'lib\\crt2.o'
+	mkdir -p $(TMPDIR)/obj
+	mv $(TMPDIR)/sysroot/lib/rustlib/$(TARGET)/lib/crt2.o $(TMPDIR)/obj/crt2.o
+	$(RUSTC) --target $(TARGET) --sysroot $(TMPDIR)/sysroot -L$(TMPDIR)/obj -Z print-link-args empty.rs | $(CGREP) 'obj\\crt2.o'
+
+else
+
+all:
+
+endif

src/test/run-make-fulldeps/libs-search-path/empty.rs

@@ -0,0 +1,11 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() {}