* vm_exec.h, tool/instruction.rb: not an error, but a BUG if stack

  overflow checking failed just before/after the beginning of an
  instruction. It should be treated as a BUG.
  Please tell us if your code cause BUG with this problem.
  This check will removed soon (for performance).



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42194 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 4 insertions, 0 deletions

diff --git a/vm_exec.h b/vm_exec.h
index 3c7e35e238..b785c4fdd3 100644
--- a/vm_exec.h
+++ b/vm_exec.h
@@ -169,5 +169,9 @@ default:                        \
 #endif
 
 #define SCREG(r) (reg_##r)
+#define CHECK_VM_STACK_OVERFLOW_FOR_INSN(cfp, margin) \
+  if ((VALUE *)((char *)(((VALUE *)(cfp)->sp) + (margin)) + sizeof(rb_control_frame_t)) >= ((VALUE *)(cfp))) { \
+      rb_bug("CHECK_VM_STACK_OVERFLOW_FOR_INSN: should not overflow here. Please contact ruby-core/dev with your (a part of) script. This check will be removed soon."); \
+  } while (0);
 
 #endif /* RUBY_VM_EXEC_H */