Create entry points for unwind frame registry in libstd.

Author: vadimcn

src/libstd/lib.rs

@@ -400,6 +400,15 @@ pub mod __rand {
     pub use rand::{thread_rng, ThreadRng, Rng};
 }
 
+// Rust runtime's startup objects depend on these symbols, so they must be public.
+// Since sys_common isn't public, we have to re-export them here explicitly.
+#[doc(hidden)]
+#[unstable(feature = "eh_frame_registry", issue = "0")]
+#[cfg(all(target_os="windows", target_arch = "x86", target_env="gnu"))]
+pub mod __frame_registry {
+    pub use sys_common::unwind::imp::eh_frame_registry::*;
+}
+
 // Include a number of private modules that exist solely to provide
 // the rustdoc documentation for primitive types. Using `include!`
 // because rustdoc only looks for these modules at the crate level.

src/libstd/sys/common/libunwind.rs

@@ -128,6 +128,10 @@ extern {}
 #[link(name = "c++abi")]
 extern {}
 
+#[cfg(all(target_os = "windows", target_env="gnu"))]
+#[link(name = "gcc_eh")]
+extern {}
+
 extern "C" {
     // iOS on armv7 uses SjLj exceptions and requires to link
     // against corresponding routine (..._SjLj_...)

src/libstd/sys/common/unwind/gcc.rs

@@ -238,3 +238,24 @@ pub mod eabi {
 unsafe extern fn rust_eh_unwind_resume(panic_ctx: *mut u8) -> ! {
     uw::_Unwind_Resume(panic_ctx as *mut uw::_Unwind_Exception);
 }
+
+#[cfg(all(target_os="windows", target_arch = "x86", target_env="gnu"))]
+pub mod eh_frame_registry {
+    #[link(name = "gcc_eh")]
+    extern {
+        fn __register_frame_info(eh_frame_begin: *const u8, object: *mut u8);
+        fn __deregister_frame_info(eh_frame_begin: *const u8, object: *mut u8);
+    }
+    #[cfg(not(test))]
+    #[no_mangle]
+    pub unsafe extern fn rust_eh_register_frames(eh_frame_begin: *const u8,
+                                                 object: *mut u8) {
+        __register_frame_info(eh_frame_begin, object);
+    }
+    #[cfg(not(test))]
+    #[no_mangle]
+    pub  unsafe extern fn rust_eh_unregister_frames(eh_frame_begin: *const u8,
+                                                   object: *mut u8) {
+        __deregister_frame_info(eh_frame_begin, object);
+    }
+}