PR#7417: ensure stack stays 16 bytes aligned

ocaml · Nov 27, 2016 · a10770e · a10770e
1 parent 34178a0
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diff --git a/Changes b/Changes
@@ -11,6 +11,10 @@ Next version (4.04.1):
 - PR#7405, GPR#903: s390x: Fix address of caml_raise_exn in native dynlink modules
   (Richard Jones, review by Xavier Leroy)
 
+- MPR#7417, GPR#930: ensure 16 byte stack alignment inside caml_allocN on x86-64
+  for ocaml build with WITH_FRAME_POINTERS defined
+  (Christoph Cullmann)
+
 - GPR#912: Fix segfault in Unix.create_process on Windows caused by wrong header
   configuration.
   (David Allsopp)

diff --git a/asmrun/amd64.S b/asmrun/amd64.S
@@ -438,12 +438,15 @@ LBL(103):
         CFI_ADJUST(8)
         RECORD_STACK_FRAME(8)
 #ifdef WITH_FRAME_POINTERS
-        /* Do we need 16-byte alignment here ? */
+        /* ensure 16 byte alignment by subq + enter using 16-bytes, PR#7417 */
+        subq    $8, %rsp; CFI_ADJUST (8)
         ENTER_FUNCTION
 #endif
         call    LBL(caml_call_gc)
 #ifdef WITH_FRAME_POINTERS
+        /* ensure 16 byte alignment by leave + addq using 16-bytes PR#7417 */
         LEAVE_FUNCTION
+        addq    $8, %rsp; CFI_ADJUST (-8)
 #endif
         popq    %rax; CFI_ADJUST(-8)       /* recover desired size */
         jmp     LBL(caml_allocN)