From 0b893eb9723f66e05b2863dce1fdfcbefde8202a Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Sun, 12 Sep 2021 14:01:41 +0200
Subject: [PATCH 1/2] remove alignment bump again

---
 compiler/gen_llvm/src/llvm/build_str.rs | 24 ++----------------------
 compiler/mono/src/layout.rs             |  4 ++--
 compiler/test_gen/src/gen_primitives.rs |  2 ++
 3 files changed, 6 insertions(+), 24 deletions(-)

diff --git a/compiler/gen_llvm/src/llvm/build_str.rs b/compiler/gen_llvm/src/llvm/build_str.rs
index 87a8c50c57..4c3c815b60 100644
--- a/compiler/gen_llvm/src/llvm/build_str.rs
+++ b/compiler/gen_llvm/src/llvm/build_str.rs
@@ -268,25 +268,19 @@ fn decode_from_utf8_result<'a, 'ctx, 'env>(
     let ctx = env.context;
 
     let fields = match env.ptr_bytes {
-        8 => [
+        8 | 4 => [
             env.ptr_int().into(),
             super::convert::zig_str_type(env).into(),
             env.context.bool_type().into(),
             ctx.i8_type().into(),
         ],
-        4 => [
-            super::convert::zig_str_type(env).into(),
-            env.ptr_int().into(),
-            env.context.bool_type().into(),
-            ctx.i8_type().into(),
-        ],
         _ => unreachable!(),
     };
 
     let record_type = env.context.struct_type(&fields, false);
 
     match env.ptr_bytes {
-        8 => {
+        8 | 4 => {
             let zig_struct = builder
                 .build_load(pointer, "load_utf8_validate_bytes_result")
                 .into_struct_value();
@@ -309,20 +303,6 @@ fn decode_from_utf8_result<'a, 'ctx, 'env>(
 
             struct_from_fields(env, record_type, values.iter().copied().enumerate())
         }
-        4 => {
-            let result_ptr_cast = env
-                .builder
-                .build_bitcast(
-                    pointer,
-                    record_type.ptr_type(AddressSpace::Generic),
-                    "to_unnamed",
-                )
-                .into_pointer_value();
-
-            builder
-                .build_load(result_ptr_cast, "load_utf8_validate_bytes_result")
-                .into_struct_value()
-        }
         _ => unreachable!(),
     }
 }
diff --git a/compiler/mono/src/layout.rs b/compiler/mono/src/layout.rs
index 3568ce5045..acc4c5fd78 100644
--- a/compiler/mono/src/layout.rs
+++ b/compiler/mono/src/layout.rs
@@ -1158,8 +1158,8 @@ impl<'a> Builtin<'a> {
             //
             // In webassembly, For that to be safe
             // they must be aligned to allow such access
-            List(_) | EmptyList => pointer_size.max(8),
-            Str | EmptyStr => pointer_size.max(8),
+            List(_) | EmptyList => pointer_size,
+            Str | EmptyStr => pointer_size,
         }
     }
 
diff --git a/compiler/test_gen/src/gen_primitives.rs b/compiler/test_gen/src/gen_primitives.rs
index 9a43cb8a78..f71ce6e98f 100644
--- a/compiler/test_gen/src/gen_primitives.rs
+++ b/compiler/test_gen/src/gen_primitives.rs
@@ -2531,6 +2531,8 @@ fn pattern_match_unit_tag() {
     );
 }
 
+// see for why this is disabled on wasm32 https://github.com/rtfeldman/roc/issues/1687
+#[cfg(not(feature = "wasm-cli-run"))]
 #[test]
 fn mirror_llvm_alignment_padding() {
     // see https://github.com/rtfeldman/roc/issues/1569

From c0cfd6ac161da2beb54560857e2484f8e0f506ea Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Sun, 12 Sep 2021 14:28:44 +0200
Subject: [PATCH 2/2] make conversion a cast again

---
 compiler/builtins/bitcode/src/str.zig   |  2 +-
 compiler/gen_llvm/src/llvm/build_str.rs | 33 +++++++++----------------
 2 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/compiler/builtins/bitcode/src/str.zig b/compiler/builtins/bitcode/src/str.zig
index 801550663c..2172e693d7 100644
--- a/compiler/builtins/bitcode/src/str.zig
+++ b/compiler/builtins/bitcode/src/str.zig
@@ -1150,8 +1150,8 @@ fn strToBytes(arg: RocStr) RocList {
 }
 
 const FromUtf8Result = extern struct {
-    string: RocStr,
     byte_index: usize,
+    string: RocStr,
     is_ok: bool,
     problem_code: Utf8ByteProblem,
 };
diff --git a/compiler/gen_llvm/src/llvm/build_str.rs b/compiler/gen_llvm/src/llvm/build_str.rs
index 4c3c815b60..80bfa0fa3a 100644
--- a/compiler/gen_llvm/src/llvm/build_str.rs
+++ b/compiler/gen_llvm/src/llvm/build_str.rs
@@ -1,5 +1,5 @@
 use crate::llvm::bitcode::{call_bitcode_fn, call_void_bitcode_fn};
-use crate::llvm::build::{complex_bitcast, struct_from_fields, Env, Scope};
+use crate::llvm::build::{complex_bitcast, Env, Scope};
 use crate::llvm::build_list::{allocate_list, call_bitcode_fn_returns_list, store_list};
 use inkwell::builder::Builder;
 use inkwell::values::{BasicValueEnum, FunctionValue, IntValue, PointerValue, StructValue};
@@ -281,27 +281,18 @@ fn decode_from_utf8_result<'a, 'ctx, 'env>(
 
     match env.ptr_bytes {
         8 | 4 => {
-            let zig_struct = builder
-                .build_load(pointer, "load_utf8_validate_bytes_result")
-                .into_struct_value();
+            let result_ptr_cast = env
+                .builder
+                .build_bitcast(
+                    pointer,
+                    record_type.ptr_type(AddressSpace::Generic),
+                    "to_unnamed",
+                )
+                .into_pointer_value();
 
-            let string = builder
-                .build_extract_value(zig_struct, 0, "string")
-                .unwrap();
-
-            let byte_index = builder
-                .build_extract_value(zig_struct, 1, "byte_index")
-                .unwrap();
-
-            let is_ok = builder.build_extract_value(zig_struct, 2, "is_ok").unwrap();
-
-            let problem_code = builder
-                .build_extract_value(zig_struct, 3, "problem_code")
-                .unwrap();
-
-            let values = [byte_index, string, is_ok, problem_code];
-
-            struct_from_fields(env, record_type, values.iter().copied().enumerate())
+            builder
+                .build_load(result_ptr_cast, "load_utf8_validate_bytes_result")
+                .into_struct_value()
         }
         _ => unreachable!(),
     }