Revert "std: Re-enable at_exit()"

This reverts commit 9e224c2bf18ebf8f871efb2e1aba43ed7970ebb7.

Conflicts:
	src/libstd/sys/windows/os.rs

1 files changed, 31 insertions, 0 deletions

diff --git a/src/libstd/sys/common/stack.rs b/src/libstd/sys/common/stack.rs
index 1966a9544e1..2a88e20c8fa 100644
--- a/src/libstd/sys/common/stack.rs
+++ b/src/libstd/sys/common/stack.rs
@@ -121,6 +121,37 @@ pub unsafe fn record_os_managed_stack_bounds(stack_lo: uint, _stack_hi: uint) {
     record_sp_limit(stack_lo + RED_ZONE);
 }
 
+#[inline(always)]
+pub unsafe fn record_rust_managed_stack_bounds(stack_lo: uint, stack_hi: uint) {
+    // When the old runtime had segmented stacks, it used a calculation that was
+    // "limit + RED_ZONE + FUDGE". The red zone was for things like dynamic
+    // symbol resolution, llvm function calls, etc. In theory this red zone
+    // value is 0, but it matters far less when we have gigantic stacks because
+    // we don't need to be so exact about our stack budget. The "fudge factor"
+    // was because LLVM doesn't emit a stack check for functions < 256 bytes in
+    // size. Again though, we have giant stacks, so we round all these
+    // calculations up to the nice round number of 20k.
+    record_sp_limit(stack_lo + RED_ZONE);
+
+    return target_record_stack_bounds(stack_lo, stack_hi);
+
+    #[cfg(not(windows))] #[inline(always)]
+    unsafe fn target_record_stack_bounds(_stack_lo: uint, _stack_hi: uint) {}
+
+    #[cfg(all(windows, target_arch = "x86"))] #[inline(always)]
+    unsafe fn target_record_stack_bounds(stack_lo: uint, stack_hi: uint) {
+        // stack range is at TIB: %fs:0x04 (top) and %fs:0x08 (bottom)
+        asm!("mov $0, %fs:0x04" :: "r"(stack_hi) :: "volatile");
+        asm!("mov $0, %fs:0x08" :: "r"(stack_lo) :: "volatile");
+    }
+    #[cfg(all(windows, target_arch = "x86_64"))] #[inline(always)]
+    unsafe fn target_record_stack_bounds(stack_lo: uint, stack_hi: uint) {
+        // stack range is at TIB: %gs:0x08 (top) and %gs:0x10 (bottom)
+        asm!("mov $0, %gs:0x08" :: "r"(stack_hi) :: "volatile");
+        asm!("mov $0, %gs:0x10" :: "r"(stack_lo) :: "volatile");
+    }
+}
+
 /// Records the current limit of the stack as specified by `end`.
 ///
 /// This is stored in an OS-dependent location, likely inside of the thread