build llvm libunwind.a in rustbuild

[rust.git] / library / unwind / src / libunwind.rs

diff --git a/library/unwind/src/libunwind.rs b/library/unwind/src/libunwind.rs
index 196be74decba4e4fb9c454f3fdf7a50ede26585e..5e15fe75a2463632f14850d7433168c16936eed8 100644 (file)
--- a/library/unwind/src/libunwind.rs
+++ b/library/unwind/src/libunwind.rs
@@ -77,9 +77,18 @@ pub enum _Unwind_Context {}
 
 pub type _Unwind_Exception_Cleanup_Fn =
     extern "C" fn(unwind_code: _Unwind_Reason_Code, exception: *mut _Unwind_Exception);
+
+// FIXME: The `#[link]` attributes on `extern "C"` block marks those symbols declared in
+// the block are reexported in dylib build of libstd. This is needed when build rustc with
+// feature `llvm-libunwind', as no other cdylib will provided those _Unwind_* symbols.
+// However the `link` attribute is duplicated multiple times and does not just export symbol,
+// a better way to manually export symbol would be another attribute like `#[export]`.
+// See the logic in function rustc_codegen_ssa::src::back::exported_symbols, module
+// rustc_codegen_ssa::src::back::symbol_export, rustc_middle::middle::exported_symbols
+// and RFC 2841
 #[cfg_attr(
     all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
-    link(name = "unwind", kind = "static")
+    link(name = "unwind", kind = "static", modifiers = "-bundle")
 )]
 extern "C-unwind" {
     pub fn _Unwind_Resume(exception: *mut _Unwind_Exception) -> !;
@@ -106,9 +115,10 @@ pub enum _Unwind_Action {
     }
     pub use _Unwind_Action::*;
 
-    #[cfg_attr(all(feature = "llvm-libunwind",
-                   any(target_os = "fuchsia", target_os = "linux")),
-               link(name = "unwind", kind = "static"))]
+    #[cfg_attr(
+        all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
+        link(name = "unwind", kind = "static", modifiers = "-bundle")
+    )]
     extern "C" {
         pub fn _Unwind_GetGR(ctx: *mut _Unwind_Context, reg_index: c_int) -> _Unwind_Word;
         pub fn _Unwind_SetGR(ctx: *mut _Unwind_Context, reg_index: c_int, value: _Unwind_Word);
@@ -163,9 +173,10 @@ enum _Unwind_VRS_DataRepresentation {
     pub const UNWIND_SP_REG: c_int = 13;
     pub const UNWIND_IP_REG: c_int = 15;
 
-    #[cfg_attr(all(feature = "llvm-libunwind",
-                   any(target_os = "fuchsia", target_os = "linux")),
-               link(name = "unwind", kind = "static"))]
+    #[cfg_attr(
+        all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
+        link(name = "unwind", kind = "static", modifiers = "-bundle")
+    )]
     extern "C" {
         fn _Unwind_VRS_Get(ctx: *mut _Unwind_Context,
                            regclass: _Unwind_VRS_RegClass,
@@ -228,9 +239,10 @@ pub unsafe fn _Unwind_FindEnclosingFunction(pc: *mut c_void) -> *mut c_void {
 cfg_if::cfg_if! {
 if #[cfg(not(all(target_os = "ios", target_arch = "arm")))] {
     // Not 32-bit iOS
-    #[cfg_attr(all(feature = "llvm-libunwind",
-                   any(target_os = "fuchsia", target_os = "linux")),
-               link(name = "unwind", kind = "static"))]
+    #[cfg_attr(
+        all(feature = "llvm-libunwind", any(target_os = "fuchsia", target_os = "linux")),
+        link(name = "unwind", kind = "static", modifiers = "-bundle")
+    )]
     extern "C-unwind" {
         pub fn _Unwind_RaiseException(exception: *mut _Unwind_Exception) -> _Unwind_Reason_Code;
     }
@@ -241,9 +253,6 @@ pub fn _Unwind_Backtrace(trace: _Unwind_Trace_Fn,
     }
 } else {
     // 32-bit iOS uses SjLj and does not provide _Unwind_Backtrace()
-    #[cfg_attr(all(feature = "llvm-libunwind",
-                   any(target_os = "fuchsia", target_os = "linux")),
-               link(name = "unwind", kind = "static"))]
     extern "C-unwind" {
         pub fn _Unwind_SjLj_RaiseException(e: *mut _Unwind_Exception) -> _Unwind_Reason_Code;
     }