rust: Implement TARGET_RUST_OS_INFO for *-*-darwin*

gcc/ChangeLog:

	* config.gcc (*-*-darwin*): Set rust_target_objs and
	target_has_targetrustm.
	* config/t-darwin (darwin-rust.o): New rule.
	* config/darwin-rust.cc: New file.

3 files changed, 50 insertions, 0 deletions

diff --git a/gcc/config.gcc b/gcc/config.gcc
index 526a7b5..01e302f 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -780,8 +780,10 @@ case ${target} in
   cxx_target_objs="${cxx_target_objs} darwin-c.o"
   d_target_objs="${d_target_objs} darwin-d.o"
   fortran_target_objs="darwin-f.o"
+  rust_target_objs="${rust_target_objs} darwin-rust.o"
   target_has_targetcm=yes
   target_has_targetdm=yes
+  target_has_targetrustm=yes
   extra_objs="${extra_objs} darwin.o"
   extra_gcc_objs="darwin-driver.o"
   default_use_cxa_atexit=yes
diff --git a/gcc/config/darwin-rust.cc b/gcc/config/darwin-rust.cc
new file mode 100644
index 0000000..4b014b8
--- /dev/null
+++ b/gcc/config/darwin-rust.cc
@@ -0,0 +1,44 @@
+/* Darwin support needed only by Rust front-end.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tm_rust.h"
+#include "rust/rust-target.h"
+#include "rust/rust-target-def.h"
+
+/* Implement TARGET_RUST_OS_INFO for Darwin targets.  */
+
+static void
+darwin_rust_target_os_info (void)
+{
+  rust_add_target_info ("target_family", "unix");
+
+  /* TODO: rust actually has "macos", "ios", and "tvos" for darwin targets, but
+     gcc seems to have no current support for them, so assuming that target_os
+     is always macos for now.  */
+  rust_add_target_info ("target_os", "macos");
+  rust_add_target_info ("target_vendor", "apple");
+  rust_add_target_info ("target_env", "");
+}
+
+#undef TARGET_RUST_OS_INFO
+#define TARGET_RUST_OS_INFO darwin_rust_target_os_info
+
+struct gcc_targetrustm targetrustm = TARGETRUSTM_INITIALIZER;
diff --git a/gcc/config/t-darwin b/gcc/config/t-darwin
index e22a579..52b6d89 100644
--- a/gcc/config/t-darwin
+++ b/gcc/config/t-darwin
@@ -34,6 +34,10 @@ darwin-f.o: $(srcdir)/config/darwin-f.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)
 
+darwin-rust.o: $(srcdir)/config/darwin-rust.cc
+	$(COMPILE) $<
+	$(POSTCOMPILE)
+
 darwin-driver.o: $(srcdir)/config/darwin-driver.cc
 	$(COMPILE) $<
 	$(POSTCOMPILE)