From ce606916a3d66f0ce2b5b09cc8154806a1a6e41c Mon Sep 17 00:00:00 2001
From: Anton-4 <17049058+Anton-4@users.noreply.github.com>
Date: Wed, 6 Mar 2024 17:15:34 +0100
Subject: [PATCH] emit-ir and style improvement

---
 crates/compiler/build/src/program.rs | 76 ++++++++++++++++------------
 1 file changed, 44 insertions(+), 32 deletions(-)

diff --git a/crates/compiler/build/src/program.rs b/crates/compiler/build/src/program.rs
index 9881ae8715..ec4a2df693 100644
--- a/crates/compiler/build/src/program.rs
+++ b/crates/compiler/build/src/program.rs
@@ -166,12 +166,11 @@ fn gen_from_mono_module_llvm<'a>(
     let context = Context::create();
     let module = arena.alloc(module_from_builtins(target, &context, "app"));
 
-    // mark our zig-defined builtins as internal
     let app_ll_file = {
-        let mut temp = PathBuf::from(roc_file_path);
-        temp.set_extension("ll");
+        let mut roc_file_path_buf = PathBuf::from(roc_file_path);
+        roc_file_path_buf.set_extension("ll");
 
-        temp
+        roc_file_path_buf
     };
 
     let kind_id = Attribute::get_named_enum_kind_id("alwaysinline");
@@ -278,27 +277,21 @@ fn gen_from_mono_module_llvm<'a>(
         );
     }
 
-    if emit_llvm_ir {
-        eprintln!("Emitting LLVM IR to {}", &app_ll_file.display());
-        module.print_to_file(&app_ll_file).unwrap();
-    }
-
     // Uncomment this to see the module's optimized LLVM instruction output:
     // env.module.print_to_stderr();
 
-    // annotate the LLVM IR output with debug info
-    // so errors are reported with the line number of the LLVM source
     let gen_sanitizers = cfg!(feature = "sanitizers") && std::env::var("ROC_SANITIZERS").is_ok();
     let memory_buffer = if fuzz || gen_sanitizers {
         let dir = tempfile::tempdir().unwrap();
         let dir = dir.into_path();
 
-        let app_ll_file = dir.join("app.ll");
-        let app_bc_file = dir.join("app.bc");
-        let app_o_file = dir.join("app.o");
+        let temp_app_ll_file = dir.join("app.ll");
+        let temp_app_processed_file = dir.join("app_processed.ll"); // app.ll with llvm passes applied
+        let temp_app_processed_file_str = temp_app_processed_file.to_str().unwrap().to_owned();
+        let temp_app_o_file = dir.join("app.o");
 
         // write the ll code to a file, so we can modify it
-        module.print_to_file(&app_ll_file).unwrap();
+        module.print_to_file(&temp_app_ll_file).unwrap();
 
         // Apply coverage passes.
         // Note, this is specifically tailored for `cargo afl` and afl++.
@@ -340,40 +333,59 @@ fn gen_from_mono_module_llvm<'a>(
         }
 
         use std::process::Command;
-        let mut opt = Command::new("opt");
-        opt.args([
-            app_ll_file.to_str().unwrap(),
-            "-o",
-            app_bc_file.to_str().unwrap(),
-        ])
-        .args(extra_args);
-        if !passes.is_empty() {
-            opt.arg(format!("-passes={}", passes.join(",")));
-        }
-        let opt = opt.output().unwrap();
 
-        assert!(opt.stderr.is_empty(), "{opt:#?}");
+        // apply passes to app.ll
+        let mut opt_command = Command::new("opt");
+
+        opt_command
+            .args([
+                temp_app_ll_file.to_str().unwrap(),
+                "-o",
+                &temp_app_processed_file_str,
+            ])
+            .args(extra_args);
+        if !passes.is_empty() {
+            opt_command.arg(format!("-passes={}", passes.join(",")));
+        }
+
+        let opt_output = opt_command.output().unwrap();
+
+        assert!(opt_output.stderr.is_empty(), "{opt_output:#?}");
+
+        if emit_llvm_ir {
+            eprintln!("Emitting LLVM IR to {}", &app_ll_file.display());
+
+            std::fs::copy(temp_app_processed_file, app_ll_file).unwrap();
+        }
 
         // write the .o file. Note that this builds the .o for the local machine,
         // and ignores the `target_machine` entirely.
         //
         // different systems name this executable differently, so we shotgun for
         // the most common ones and then give up.
-        let bc_to_object = Command::new("llc")
+        let bc_to_object_output = Command::new("llc")
             .args([
                 "-relocation-model=pic",
                 "-filetype=obj",
-                app_bc_file.to_str().unwrap(),
+                &temp_app_processed_file_str,
                 "-o",
-                app_o_file.to_str().unwrap(),
+                temp_app_o_file.to_str().unwrap(),
             ])
             .output()
             .unwrap();
 
-        assert!(bc_to_object.status.success(), "{bc_to_object:#?}");
+        assert!(
+            bc_to_object_output.status.success(),
+            "{bc_to_object_output:#?}"
+        );
 
-        MemoryBuffer::create_from_file(&app_o_file).expect("memory buffer creation works")
+        MemoryBuffer::create_from_file(&temp_app_o_file).expect("memory buffer creation works")
     } else {
+        if emit_llvm_ir {
+            eprintln!("Emitting LLVM IR to {}", &app_ll_file.display());
+            module.print_to_file(&app_ll_file).unwrap();
+        }
+
         // Emit the .o file
         use target_lexicon::Architecture;
         match target.architecture {