From 9fc5a5dbedf70d6026ff8b76a57297b8021c5dcd Mon Sep 17 00:00:00 2001
From: Max Bernstein <max.bernstein@shopify.com>
Date: Tue, 22 Apr 2025 12:17:35 -0400
Subject: [PATCH] ZJIT: Add option to dump LIR (#13139)

Now we can dump HIR, optimized HIR, LIR, and assembly.
---
 zjit/src/codegen.rs | 5 +++++
 zjit/src/options.rs | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/zjit/src/codegen.rs b/zjit/src/codegen.rs
index 1235eab9af..0963aaa5b8 100644
--- a/zjit/src/codegen.rs
+++ b/zjit/src/codegen.rs
@@ -10,6 +10,7 @@ use crate::backend::lir::{self, asm_comment, Assembler, Opnd, Target, CFP, C_ARG
 use crate::hir::{iseq_to_hir, Block, BlockId, BranchEdge, CallInfo};
 use crate::hir::{Const, FrameState, Function, Insn, InsnId};
 use crate::hir_type::{types::Fixnum, Type};
+use crate::options::get_option;
 
 /// Ephemeral code generation state
 struct JITState {
@@ -223,6 +224,10 @@ fn gen_function(cb: &mut CodeBlock, iseq: IseqPtr, function: &Function) -> Optio
         }
     }
 
+    if get_option!(dump_lir) {
+        println!("LIR:\nfn {}:\n{:?}", iseq_name(iseq), asm);
+    }
+
     // Generate code if everything can be compiled
     asm.compile(cb).map(|(start_ptr, _)| (start_ptr, jit.branch_iseqs))
 }
diff --git a/zjit/src/options.rs b/zjit/src/options.rs
index 5a51b9f2c1..ebcad7bef2 100644
--- a/zjit/src/options.rs
+++ b/zjit/src/options.rs
@@ -27,6 +27,9 @@ pub struct Options {
     /// Dump High-level IR after optimization, right before codegen.
     pub dump_hir_opt: Option<DumpHIR>,
 
+    /// Dump low-level IR
+    pub dump_lir: bool,
+
     /// Dump all compiled machine code.
     pub dump_disasm: bool,
 }
@@ -70,6 +73,7 @@ pub fn init_options() -> Options {
         debug: false,
         dump_hir_init: None,
         dump_hir_opt: None,
+        dump_lir: false,
         dump_disasm: false,
     }
 }
@@ -127,6 +131,8 @@ fn parse_option(options: &mut Options, str_ptr: *const std::os::raw::c_char) ->
         ("dump-hir-init", "all") => options.dump_hir_init = Some(DumpHIR::All),
         ("dump-hir-init", "debug") => options.dump_hir_init = Some(DumpHIR::Debug),
 
+        ("dump-lir", "") => options.dump_lir = true,
+
         ("dump-disasm", "") => options.dump_disasm = true,
 
         _ => return None, // Option name not recognized