auto merge of #10812 : alexcrichton/rust/lto, r=pcwalton

The first commit was approved from another pull request, but I wanted to rebase LTO on top of it.

LTO is not turned on by default at all, and it's hidden behind a `-Z` flag. I have added a few small tests for it, however.

6 files changed, 31 insertions, 0 deletions

diff --git a/src/test/run-make/lto-smoke-c/Makefile b/src/test/run-make/lto-smoke-c/Makefile
new file mode 100644
index 00000000000..a491fda7dc2
--- /dev/null
+++ b/src/test/run-make/lto-smoke-c/Makefile
@@ -0,0 +1,11 @@
+-include ../tools.mk
+
+ifneq ($(shell uname),Darwin)
+	EXTRAFLAGS := -lm -lrt -ldl -lpthread
+endif
+
+all:
+	$(RUSTC) foo.rs -Z gen-crate-map -Z lto
+	ln -s $(call STATICLIB,foo-*) $(call STATICLIB,foo)
+	$(CC) bar.c -lfoo -o $(call RUN,bar) $(EXTRAFLAGS) -lstdc++
+	$(call RUN,bar)
diff --git a/src/test/run-make/lto-smoke-c/bar.c b/src/test/run-make/lto-smoke-c/bar.c
new file mode 100644
index 00000000000..bb4036b06e1
--- /dev/null
+++ b/src/test/run-make/lto-smoke-c/bar.c
@@ -0,0 +1,6 @@
+void foo();
+
+int main() {
+    foo();
+    return 0;
+}
diff --git a/src/test/run-make/lto-smoke-c/foo.rs b/src/test/run-make/lto-smoke-c/foo.rs
new file mode 100644
index 00000000000..3da09eb6bb6
--- /dev/null
+++ b/src/test/run-make/lto-smoke-c/foo.rs
@@ -0,0 +1,4 @@
+#[crate_type = "staticlib"];
+
+#[no_mangle]
+pub extern "C" fn foo() {}
diff --git a/src/test/run-make/lto-smoke/Makefile b/src/test/run-make/lto-smoke/Makefile
new file mode 100644
index 00000000000..4652556d344
--- /dev/null
+++ b/src/test/run-make/lto-smoke/Makefile
@@ -0,0 +1,6 @@
+-include ../tools.mk
+
+all:
+	$(RUSTC) lib.rs
+	$(RUSTC) main.rs -Z lto
+	$(call RUN,main)
diff --git a/src/test/run-make/lto-smoke/lib.rs b/src/test/run-make/lto-smoke/lib.rs
new file mode 100644
index 00000000000..3cdacc96ee9
--- /dev/null
+++ b/src/test/run-make/lto-smoke/lib.rs
@@ -0,0 +1 @@
+#[crate_type = "rlib"];
diff --git a/src/test/run-make/lto-smoke/main.rs b/src/test/run-make/lto-smoke/main.rs
new file mode 100644
index 00000000000..a3ed6772926
--- /dev/null
+++ b/src/test/run-make/lto-smoke/main.rs
@@ -0,0 +1,3 @@
+extern mod lib;
+
+fn main() {}