From 27fe50ce9ec639ecd1d8698972f368494656fc5b Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nick@wasmer.io>
Date: Wed, 4 Dec 2019 10:38:28 -0800
Subject: [PATCH 1/2] Fix this regression test to detect the bug it was looking
 for in release builds too.

This bug triggered an assertion failure in debug, and by examining the pre-opt IR, we can check for the bug in release mode too.
---
 lib/llvm-backend-tests/tests/compile.rs | 62 +++++++++++++++++++------
 1 file changed, 47 insertions(+), 15 deletions(-)

diff --git a/lib/llvm-backend-tests/tests/compile.rs b/lib/llvm-backend-tests/tests/compile.rs
index 17071a44a04..dc539bf2067 100644
--- a/lib/llvm-backend-tests/tests/compile.rs
+++ b/lib/llvm-backend-tests/tests/compile.rs
@@ -1,40 +1,72 @@
+use wasmer_llvm_backend::{InkwellMemoryBuffer, InkwellModule, LLVMBackendConfig, LLVMCallbacks};
 use wasmer_llvm_backend_tests::{get_compiler, wat2wasm};
-use wasmer_runtime::imports;
-use wasmer_runtime_core::compile_with;
+use wasmer_runtime::{imports, CompilerConfig};
+use wasmer_runtime_core::{backend::BackendCompilerConfig, compile_with, compile_with_config};
+
+use std::cell::RefCell;
+use std::rc::Rc;
 
 #[test]
 fn crash_return_with_float_on_stack() {
     const MODULE: &str = r#"
 (module
-  (type (;0;) (func))
-  (type (;1;) (func (param f64) (result f64)))
+  (type (func))
+  (type (func (param f64) (result f64)))
   (func $_start (type 0))
   (func $fmod (type 1) (param f64) (result f64)
     local.get 0
-    f64.const 0x0p+0 (;=0;)
+    f64.const 0x0p+0
     f64.mul
-    return)
-)
+    return))
 "#;
     let wasm_binary = wat2wasm(MODULE.as_bytes()).expect("WAST not valid or malformed");
     let module = compile_with(&wasm_binary, &get_compiler()).unwrap();
     module.instantiate(&imports! {}).unwrap();
 }
 
+#[derive(Debug, Default)]
+pub struct RecordPreOptIR {
+    preopt_ir: String,
+}
+
+impl LLVMCallbacks for RecordPreOptIR {
+    fn preopt_ir_callback(&mut self, module: &InkwellModule) {
+        self.preopt_ir = module.print_to_string().to_string();
+    }
+
+    fn postopt_ir_callback(&mut self, _: &InkwellModule) {}
+
+    fn obj_memory_buffer_callback(&mut self, _: &InkwellMemoryBuffer) {}
+}
+
 #[test]
 fn crash_select_with_mismatched_pending() {
-    const MODULE: &str = r#"
+    const WAT: &str = r#"
  (module
-  (func (param f64)
-    f64.const 0x0p+0 (;=0;)
+  (func (param f64) (result f64)
+    f64.const 0x0p+0
     local.get 0
     f64.add
-    f64.const 0x0p+0 (;=0;)
+    f64.const 0x0p+0
     i32.const 0
-    select
-    drop))
+    select))
 "#;
-    let wasm_binary = wat2wasm(MODULE.as_bytes()).expect("WAST not valid or malformed");
-    let module = compile_with(&wasm_binary, &get_compiler()).unwrap();
+    let record_pre_opt_ir = Rc::new(RefCell::new(RecordPreOptIR::default()));
+    let compiler_config = CompilerConfig {
+        backend_specific_config: Some(BackendCompilerConfig(Box::new(LLVMBackendConfig {
+            callbacks: Some(record_pre_opt_ir.clone()),
+        }))),
+        ..Default::default()
+    };
+    let wasm_binary = wat2wasm(WAT.as_bytes()).expect("WAST not valid or malformed");
+    let module = compile_with_config(&wasm_binary, &get_compiler(), compiler_config).unwrap();
     module.instantiate(&imports! {}).unwrap();
+    const LLVM: &str = r#"
+  %s3 = fadd double 0.000000e+00, %s2
+  %nan = fcmp uno double %s3, 0.000000e+00
+  %2 = select i1 %nan, double 0x7FF8000000000000, double %s3
+  %s5 = select i1 false, double %2, double 0.000000e+00
+  br label %return
+"#;
+    assert!(&record_pre_opt_ir.borrow().preopt_ir.contains(LLVM));
 }

From a221f1e5707fce40c08b09632341832483781e3a Mon Sep 17 00:00:00 2001
From: Nick Lewycky <nick@wasmer.io>
Date: Fri, 6 Dec 2019 12:09:34 -0800
Subject: [PATCH 2/2] Provide a default empty implementation for the
 LLVMCallbacks trait.

---
 lib/llvm-backend-tests/tests/compile.rs | 4 ----
 lib/llvm-backend/src/lib.rs             | 6 +++---
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/lib/llvm-backend-tests/tests/compile.rs b/lib/llvm-backend-tests/tests/compile.rs
index dc539bf2067..1e32f6dd08d 100644
--- a/lib/llvm-backend-tests/tests/compile.rs
+++ b/lib/llvm-backend-tests/tests/compile.rs
@@ -33,10 +33,6 @@ impl LLVMCallbacks for RecordPreOptIR {
     fn preopt_ir_callback(&mut self, module: &InkwellModule) {
         self.preopt_ir = module.print_to_string().to_string();
     }
-
-    fn postopt_ir_callback(&mut self, _: &InkwellModule) {}
-
-    fn obj_memory_buffer_callback(&mut self, _: &InkwellMemoryBuffer) {}
 }
 
 #[test]
diff --git a/lib/llvm-backend/src/lib.rs b/lib/llvm-backend/src/lib.rs
index 853cfac1195..a2db088a76a 100644
--- a/lib/llvm-backend/src/lib.rs
+++ b/lib/llvm-backend/src/lib.rs
@@ -37,9 +37,9 @@ pub type InkwellModule<'ctx> = inkwell::module::Module<'ctx>;
 pub type InkwellMemoryBuffer = inkwell::memory_buffer::MemoryBuffer;
 
 pub trait LLVMCallbacks: std::any::Any + 'static {
-    fn preopt_ir_callback(&mut self, module: &InkwellModule);
-    fn postopt_ir_callback(&mut self, module: &InkwellModule);
-    fn obj_memory_buffer_callback(&mut self, memory_buffer: &InkwellMemoryBuffer);
+    fn preopt_ir_callback(&mut self, _module: &InkwellModule) {}
+    fn postopt_ir_callback(&mut self, _module: &InkwellModule) {}
+    fn obj_memory_buffer_callback(&mut self, _memory_buffer: &InkwellMemoryBuffer) {}
 }
 
 pub struct LLVMBackendConfig {