Auto merge of #28358 - dotdash:nounwind, r=alexcrichton

This allows to skip the codegen for all the unneeded landing pads, reducing code size across the board by about 2-5%, depending on the crate. Compile times seem to be pretty unaffected though :-/

5 files changed, 7 insertions, 0 deletions

diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 868fef06aa4..774d13966bd 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -242,6 +242,7 @@
 #![feature(unique)]
 #![feature(unsafe_no_drop_flag, filling_drop)]
 #![feature(decode_utf16)]
+#![feature(unwind_attributes)]
 #![feature(vec_push_all)]
 #![feature(vec_resize)]
 #![feature(wrapping)]
diff --git a/src/libstd/sys/common/libunwind.rs b/src/libstd/sys/common/libunwind.rs
index fde612014e9..c6bffb0f733 100644
--- a/src/libstd/sys/common/libunwind.rs
+++ b/src/libstd/sys/common/libunwind.rs
@@ -124,10 +124,12 @@ extern "C" {
     // iOS on armv7 uses SjLj exceptions and requires to link
     // against corresponding routine (..._SjLj_...)
     #[cfg(not(all(target_os = "ios", target_arch = "arm")))]
+    #[unwind]
     pub fn _Unwind_RaiseException(exception: *mut _Unwind_Exception)
                                   -> _Unwind_Reason_Code;
 
     #[cfg(all(target_os = "ios", target_arch = "arm"))]
+    #[unwind]
     fn _Unwind_SjLj_RaiseException(e: *mut _Unwind_Exception)
                                    -> _Unwind_Reason_Code;
 
diff --git a/src/libstd/sys/common/unwind/mod.rs b/src/libstd/sys/common/unwind/mod.rs
index ff93d0526b7..738681c3cfe 100644
--- a/src/libstd/sys/common/unwind/mod.rs
+++ b/src/libstd/sys/common/unwind/mod.rs
@@ -192,6 +192,7 @@ fn rust_panic(cause: Box<Any + Send + 'static>) -> ! {
 #[cfg(not(test))]
 /// Entry point of panic from the libcore crate.
 #[lang = "panic_fmt"]
+#[unwind]
 pub extern fn rust_begin_unwind(msg: fmt::Arguments,
                                 file: &'static str, line: u32) -> ! {
     begin_unwind_fmt(msg, &(file, line))
diff --git a/src/libstd/sys/common/unwind/seh.rs b/src/libstd/sys/common/unwind/seh.rs
index a201e406a23..a89e8b499ac 100644
--- a/src/libstd/sys/common/unwind/seh.rs
+++ b/src/libstd/sys/common/unwind/seh.rs
@@ -62,6 +62,7 @@ static PANIC_DATA: StaticKey = StaticKey::new(None);
 
 // This function is provided by kernel32.dll
 extern "system" {
+    #[unwind]
     fn RaiseException(dwExceptionCode: DWORD,
                       dwExceptionFlags: DWORD,
                       nNumberOfArguments: DWORD,
diff --git a/src/libstd/sys/common/unwind/seh64_gnu.rs b/src/libstd/sys/common/unwind/seh64_gnu.rs
index 4d23794de24..9478678fda9 100644
--- a/src/libstd/sys/common/unwind/seh64_gnu.rs
+++ b/src/libstd/sys/common/unwind/seh64_gnu.rs
@@ -93,6 +93,7 @@ pub enum EXCEPTION_DISPOSITION {
 
 // From kernel32.dll
 extern "system" {
+    #[unwind]
     fn RaiseException(dwExceptionCode: DWORD,
                       dwExceptionFlags: DWORD,
                       nNumberOfArguments: DWORD,
@@ -198,6 +199,7 @@ unsafe extern fn rust_eh_personality(
 
 #[lang = "eh_unwind_resume"]
 #[cfg(not(test))]
+#[unwind]
 unsafe extern fn rust_eh_unwind_resume(panic_ctx: LPVOID) {
     let params = [panic_ctx as ULONG_PTR];
     RaiseException(RUST_PANIC,