From ccbf4441de3e7e99a456f699d8c05c77e2dd2e51 Mon Sep 17 00:00:00 2001
From: Max Bernstein <max.bernstein@shopify.com>
Date: Thu, 13 Feb 2025 09:17:41 -0500
Subject: [PATCH] Add comments for Test and Snapshot

---
 zjit/src/ir.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/zjit/src/ir.rs b/zjit/src/ir.rs
index 0002892530..7e552872c0 100644
--- a/zjit/src/ir.rs
+++ b/zjit/src/ir.rs
@@ -85,6 +85,8 @@ pub enum Insn {
     NewArray { count: usize },
     ArraySet { idx: usize, val: Opnd },
     ArrayDup { val: Opnd },
+    // Check if the value is truthy and "return" a C boolean. In reality, we will likely fuse this
+    // with IfTrue/IfFalse in the backend to generate jcc.
     Test { val: Opnd },
     Defined { op_type: usize, obj: VALUE, pushval: VALUE, v: Opnd },
     GetConstantPath { ic: *const u8 },
@@ -93,6 +95,9 @@ pub enum Insn {
     //SetIvar {},
     //GetIvar {},
 
+    // Own a FrameState so that instructions can look up their dominating FrameState when
+    // generating deopt side-exits and frame reconstruction metadata. Does not directly generate
+    // any code.
     Snapshot { state: FrameState },
 
     // Unconditional jump