* only adjust the stack pointer of the signal context if it's aligned (it

    may still be unaligned in case the signal got raised in a leaf function)

git-svn-id: trunk@40771 -

rtl/darwin/x86/x86hnd.inc

@@ -80,9 +80,11 @@ begin
       sigcontext^.uc_mcontext^.ts.rdi:=res;
       sigcontext^.uc_mcontext^.ts.rsi:=sigcontext^.uc_mcontext^.ts.rip;
       sigcontext^.uc_mcontext^.ts.rdx:=sigcontext^.uc_mcontext^.ts.rbp;
-      { the ABI expects the stack pointer to be 4 bytes off alignment }
-      { due to the return address which has been pushed               }
-      dec(sigcontext^.uc_mcontext^.ts.rsp,sizeof(pointer));
+      { the ABI expects the stack pointer to be 8 bytes off alignment
+        due to the return address which has been pushed -- but take into account
+        that rsp may already unaligned in case of a leaf routine }
+      if (sigcontext^.uc_mcontext^.ts.rsp and 15)=0 then
+        dec(sigcontext^.uc_mcontext^.ts.rsp,sizeof(pointer));
       { return to run time error handler }
       sigcontext^.uc_mcontext^.ts.rip:=ptruint(@HandleErrorAddrFrame);
 {$else cpu64}
@@ -90,9 +92,11 @@ begin
       sigcontext^.uc_mcontext^.ts.eax:=res;
       sigcontext^.uc_mcontext^.ts.edx:=sigcontext^.uc_mcontext^.ts.eip;
       sigcontext^.uc_mcontext^.ts.ecx:=sigcontext^.uc_mcontext^.ts.ebp;
-      { the ABI expects the stack pointer to be 8 bytes off alignment }
-      { due to the return address which has been pushed               }
-      dec(sigcontext^.uc_mcontext^.ts.esp,sizeof(pointer));
+      { the ABI expects the stack pointer to be 4 bytes off alignment }
+      { due to the return address which has been pushed -- but take into account
+        that esp may already unaligned in case of a leaf routine }
+      if (sigcontext^.uc_mcontext^.ts.rsp and 15)=0 then
+        dec(sigcontext^.uc_mcontext^.ts.esp,sizeof(pointer));
       { return to run time error handler }
       sigcontext^.uc_mcontext^.ts.eip:=ptruint(@HandleErrorAddrFrame);
 {$endif cpu64}