rust: Implement TARGET_RUST_OS_INFO for *-*-*linux*.

gcc/ChangeLog:

	* config.gcc (*linux*): Set rust target_objs, and
	target_has_targetrustm,
	* config/t-linux (linux-rust.o): New rule.
	* config/linux-rust.cc: New file.

3 files changed, 63 insertions, 0 deletions

diff --git a/gcc/config.gcc b/gcc/config.gcc
index 1a01d97..ee46d96 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -945,6 +945,8 @@ case ${target} in
     *-*-*linux*)
       d_target_objs="${d_target_objs} linux-d.o"
       target_has_targetdm=yes
+      rust_target_objs="${rust_target_objs} linux-rust.o"
+      target_has_targetrustm=yes
       ;;
     *-*-kfreebsd*-gnu)
       d_target_objs="${d_target_objs} kfreebsd-d.o"
diff --git a/gcc/config/linux-rust.cc b/gcc/config/linux-rust.cc
new file mode 100644
index 0000000..3eaa918
--- /dev/null
+++ b/gcc/config/linux-rust.cc
@@ -0,0 +1,57 @@
+/* Linux 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"
+
+/* `-mandroid' is not available as an command-line option.  */
+#ifndef TARGET_ANDROID
+#define TARGET_ANDROID 0
+#endif
+
+/* Implement TARGET_RUST_OS_INFO for Linux targets.  */
+
+static void
+linux_rust_target_os_info (void)
+{
+  rust_add_target_info ("target_family", "unix");
+  rust_add_target_info ("target_vendor", "unknown");
+
+  if (TARGET_ANDROID)
+    rust_add_target_info ("target_os", "android");
+  else
+    rust_add_target_info ("target_os", "linux");
+
+  if (OPTION_GLIBC)
+    rust_add_target_info ("target_env", "gnu");
+  else if (OPTION_MUSL)
+    rust_add_target_info ("target_env", "musl");
+  else if (OPTION_UCLIBC)
+    rust_add_target_info ("target_env", "uclibc");
+  else
+    rust_add_target_info ("target_env", "");
+}
+
+#undef TARGET_RUST_OS_INFO
+#define TARGET_RUST_OS_INFO linux_rust_target_os_info
+
+struct gcc_targetrustm targetrustm = TARGETRUSTM_INITIALIZER;
diff --git a/gcc/config/t-linux b/gcc/config/t-linux
index 03966d5..96593fb 100644
--- a/gcc/config/t-linux
+++ b/gcc/config/t-linux
@@ -23,3 +23,7 @@ linux.o: $(srcdir)/config/linux.cc
 linux-d.o: $(srcdir)/config/linux-d.cc
 	  $(COMPILE) $<
 	  $(POSTCOMPILE)
+
+linux-rust.o: $(srcdir)/config/linux-rust.cc
+	  $(COMPILE) $<
+	  $(POSTCOMPILE)