From 3b97bcea13da6b21452bce4136ad6e54f28c9348 Mon Sep 17 00:00:00 2001
From: Max Bernstein <max.bernstein@shopify.com>
Date: Fri, 7 Feb 2025 13:09:07 -0500
Subject: [PATCH] Give context in StackUnderflow

---
 zjit/src/ir.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/zjit/src/ir.rs b/zjit/src/ir.rs
index 52454594de..66c9c7a5f0 100644
--- a/zjit/src/ir.rs
+++ b/zjit/src/ir.rs
@@ -229,11 +229,11 @@ impl FrameState {
     }
 
     fn top(&self) -> Result<Opnd, ParseError> {
-        self.stack.last().ok_or(ParseError::StackUnderflow).copied()
+        self.stack.last().ok_or_else(|| ParseError::StackUnderflow(self.clone())).copied()
     }
 
     fn pop(&mut self) -> Result<Opnd, ParseError> {
-        self.stack.pop().ok_or(ParseError::StackUnderflow)
+        self.stack.pop().ok_or_else(|| ParseError::StackUnderflow(self.clone()))
     }
 
     fn setn(&mut self, n: usize, opnd: Opnd) {
@@ -308,7 +308,7 @@ fn compute_jump_targets(iseq: *const rb_iseq_t) -> Vec<u32> {
 
 #[derive(Debug)]
 pub enum ParseError {
-    StackUnderflow,
+    StackUnderflow(FrameState),
 }
 
 pub fn iseq_to_ssa(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {