1 files changed, 40 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/x86_64/chkstk.S b/contrib/llvm-project/compiler-rt/lib/builtins/x86_64/chkstk.S
new file mode 100644
index 000000000000..ad7953a116ac
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/builtins/x86_64/chkstk.S
@@ -0,0 +1,40 @@
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include "../assembly.h"
+
+// _chkstk routine
+// This routine is windows specific
+// http://msdn.microsoft.com/en-us/library/ms648426.aspx
+
+// Notes from r227519
+// MSVC x64s __chkstk and cygmings ___chkstk_ms do not adjust %rsp
+// themselves. It also does not clobber %rax so we can reuse it when
+// adjusting %rsp.
+
+#ifdef __x86_64__
+
+.text
+.balign 4
+DEFINE_COMPILERRT_FUNCTION(___chkstk_ms)
+        push   %rcx
+        push   %rax
+        cmp    $0x1000,%rax
+        lea    24(%rsp),%rcx
+        jb     1f
+2:
+        sub    $0x1000,%rcx
+        test   %rcx,(%rcx)
+        sub    $0x1000,%rax
+        cmp    $0x1000,%rax
+        ja     2b
+1:
+        sub    %rax,%rcx
+        test   %rcx,(%rcx)
+        pop    %rax
+        pop    %rcx
+        ret
+END_COMPILERRT_FUNCTION(___chkstk_ms)
+
+#endif // __x86_64__