auto merge of #11046 : zargony/rust/dep-info, r=alexcrichton

Using --dep-info writes Makefile-compatible dependency info to a file that is by default named based on the crate source filename. This adds an optional string argument to the --dep-info option which allows to write dependency info to an arbitrary filename.

cc #10698

src/librustc/driver/driver.rs

@@ -393,25 +393,34 @@ pub fn phase_6_link_output(sess: Session,
                            &outputs.out_filename,
                            &trans.link));
 
-    // Write out dependency rules to the .d file if requested
-    if sess.opts.write_dependency_info {
-        match *input {
+    // Write out dependency rules to the dep-info file if requested with --dep-info
+    let deps_filename = match sess.opts.write_dependency_info {
+        // Use filename from --dep-file argument if given
+        (true, Some(ref filename)) => filename.clone(),
+        // Use default filename: crate source filename with extension replaced by ".d"
+        (true, None) => match *input {
             file_input(ref input_path) => {
+                let filestem = input_path.filestem().expect("input file must have stem");
+                let filename = outputs[0].dir_path().join(filestem).with_extension("d");
+                filename
+            },
+            str_input(..) => {
+                sess.warn("can not write --dep-info without a filename when compiling stdin.");
+                return;
+            },
+        },
+        _ => return,
+    };
+    // Build a list of files used to compile the output and
+    // write Makefile-compatible dependency rules
     let files: ~[@str] = sess.codemap.files.iter()
         .filter_map(|fmap| if fmap.is_real_file() { Some(fmap.name) } else { None })
         .collect();
-                let mut output_path = outputs[0].dir_path();
-                let filestem = input_path.filestem().expect("input file must have stem");
-                output_path.push(Path::new(filestem).with_extension("d"));
-                let mut file = io::File::create(&output_path);
+    let mut file = io::File::create(&deps_filename);
     for output in outputs.iter() {
         write!(&mut file as &mut Writer,
                "{}: {}\n\n", output.display(), files.connect(" "));
     }
-            }
-            str_input(_) => {}
-        }
-    }
 }
 
 pub fn stop_after_phase_3(sess: Session) -> bool {
@@ -771,7 +780,8 @@ pub fn build_session_options(binary: @str,
     let cfg = parse_cfgspecs(matches.opt_strs("cfg"), demitter);
     let test = matches.opt_present("test");
     let android_cross_path = matches.opt_str("android-cross-path");
-    let write_dependency_info = matches.opt_present("dep-info");
+    let write_dependency_info = (matches.opt_present("dep-info"),
+                                 matches.opt_str("dep-info").map(|p| Path::new(p)));
 
     let custom_passes = match matches.opt_str("passes") {
         None => ~[],
@@ -933,8 +943,8 @@ pub fn optgroups() -> ~[getopts::groups::OptGroup] {
                           or identified (fully parenthesized,
                           AST nodes and blocks with IDs)", "TYPE"),
   optflag("S", "",    "Compile only; do not assemble or link"),
-  optflag("", "dep-info",
-                        "Output dependency info to .d file after compiling"),
+  optflagopt("", "dep-info",
+                        "Output dependency info to <filename> after compiling", "FILENAME"),
   optflag("", "save-temps",
                         "Write intermediate files (.bc, .opt.bc, .o)
                           in addition to normal output"),

src/librustc/driver/session.rs

@@ -168,8 +168,8 @@ pub struct options {
     no_trans: bool,
     debugging_opts: uint,
     android_cross_path: Option<~str>,
-    /// Whether to write .d dependency files
-    write_dependency_info: bool,
+    /// Whether to write dependency files. It's (enabled, optional filename).
+    write_dependency_info: (bool, Option<Path>),
     /// Crate id-related things to maybe print. It's (crate_id, crate_name, crate_file_name).
     print_metas: (bool, bool, bool),
 }
@@ -397,7 +397,7 @@ pub fn basic_options() -> @options {
         no_trans: false,
         debugging_opts: 0u,
         android_cross_path: None,
-        write_dependency_info: false,
+        write_dependency_info: (false, None),
         print_metas: (false, false, false),
     }
 }

src/test/run-make/dep-info-custom/Makefile

@@ -0,0 +1,12 @@
+-include ../tools.mk
+
+all:
+	$(RUSTC) --dep-info $(TMPDIR)/custom-deps-file.d --lib lib.rs
+	sleep 1
+	touch foo.rs
+	-rm -f $(TMPDIR)/done
+	$(MAKE) -drf Makefile.foo
+	rm $(TMPDIR)/done
+	pwd
+	$(MAKE) -drf Makefile.foo
+	rm $(TMPDIR)/done && exit 1 || exit 0

src/test/run-make/dep-info-custom/Makefile.foo

@@ -0,0 +1,7 @@
+LIB := $(shell $(RUSTC) --crate-file-name --lib lib.rs)
+
+$(TMPDIR)/$(LIB):
+	$(RUSTC) --dep-info $(TMPDIR)/custom-deps-file.d --lib lib.rs
+	touch $(TMPDIR)/done
+
+-include $(TMPDIR)/custom-deps-file.d

src/test/run-make/dep-info-custom/bar.rs

@@ -0,0 +1 @@
+pub fn bar() {}

src/test/run-make/dep-info-custom/foo.rs

@@ -0,0 +1 @@
+pub fn foo() {}

src/test/run-make/dep-info-custom/lib.rs

@@ -0,0 +1,4 @@
+#[crate_id="foo#0.1"];
+
+pub mod foo;
+pub mod bar;

src/test/run-make/dep-info/Makefile

@@ -1,11 +1,12 @@
 -include ../tools.mk
+
 all:
 	$(RUSTC) --dep-info --lib lib.rs
 	sleep 1
 	touch foo.rs
 	-rm -f $(TMPDIR)/done
-	$(MAKE) -f Makefile.foo
+	$(MAKE) -drf Makefile.foo
 	rm $(TMPDIR)/done
 	pwd
-	$(MAKE) -df Makefile.foo
+	$(MAKE) -drf Makefile.foo
 	rm $(TMPDIR)/done && exit 1 || exit 0

src/test/run-make/dep-info/Makefile.foo

@@ -1,10 +1,6 @@
-ifeq ($(shell uname),Darwin)
-LIBEXT=dylib
-else
-LIBEXT=so
-endif
+LIB := $(shell $(RUSTC) --crate-file-name --lib lib.rs)
 
-$(TMPDIR)/libfoo-b517899a-0.1.$(LIBEXT):
+$(TMPDIR)/$(LIB):
 	$(RUSTC) --dep-info --lib lib.rs
 	touch $(TMPDIR)/done