Zero out RBP in order not to compromise the environment encryption.

src/jit.rs

@@ -111,6 +111,8 @@ impl JitProgram {
                 // RBP and RBX must be saved and restored manually in the current version of rustc and llvm.
                 "push rbx",
                 "push rbp",
+                // RBP is zeroed out in order not to compromise the runtime environment (RDI) encryption.
+                "xor rbp, rbp",
                 "mov [{host_stack_pointer}], rsp",
                 "add QWORD PTR [{host_stack_pointer}], -8", // We will push RIP in "call rbp" later
                 "mov [rsp-8], rax",