From e02dbf1bc238e6401c8f827a4d44d3896662b548 Mon Sep 17 00:00:00 2001
From: Sergey Pepyakin <sergei@parity.io>
Date: Tue, 11 Dec 2018 20:12:55 +0100
Subject: [PATCH] Add i32 literals support.

---
 src/backend.rs       | 10 +++++++++-
 src/function_body.rs |  3 +++
 src/tests.rs         | 14 ++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/backend.rs b/src/backend.rs
index dfcd301c32..3e90722c00 100644
--- a/src/backend.rs
+++ b/src/backend.rs
@@ -261,7 +261,7 @@ pub fn get_local_i32(ctx: &mut Context, local_idx: u32) {
     push_i32(ctx, gpr);
 }
 
-pub fn store_i32(ctx: &mut Context, local_idx: u32) {
+pub fn set_local_i32(ctx: &mut Context, local_idx: u32) {
     let gpr = pop_i32(ctx);
     let offset = sp_relative_offset(ctx, local_idx);
     dynasm!(ctx.asm
@@ -270,6 +270,14 @@ pub fn store_i32(ctx: &mut Context, local_idx: u32) {
     ctx.regs.release_scratch_gpr(gpr);
 }
 
+pub fn literal_i32(ctx: &mut Context, imm: i32) {
+    let gpr = ctx.regs.take_scratch_gpr();
+    dynasm!(ctx.asm
+        ; mov Rd(gpr), imm
+    );
+    push_i32(ctx, gpr);
+}
+
 pub fn relop_eq_i32(ctx: &mut Context) {
     let right = pop_i32(ctx);
     let left = pop_i32(ctx);
diff --git a/src/function_body.rs b/src/function_body.rs
index bffca70b98..fca2a7e666 100644
--- a/src/function_body.rs
+++ b/src/function_body.rs
@@ -217,6 +217,9 @@ pub fn translate(
             Operator::GetLocal { local_index } => {
                 get_local_i32(&mut ctx, local_index);
             }
+            Operator::I32Const { value } => {
+                literal_i32(&mut ctx, value);
+            }
             Operator::Call { function_index } => {
                 let callee_ty = translation_ctx.func_type(function_index);
                 assert!(callee_ty.returns.len() == 0, "is not supported");
diff --git a/src/tests.rs b/src/tests.rs
index d2e2effb78..348c0e772f 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -129,4 +129,18 @@ fn function_call() {
     assert_eq!(execute_wat(code, 2, 0), 2);
 }
 
+#[test]
+fn literals() {
+    let code = r#"
+(module
+  (func (param i32) (param i32) (result i32)
+    (i32.const 228)
+  )
+)
+    "#;
+
+    assert_eq!(execute_wat(code, 0, 0), 228);
+}
+
+
 // TODO: Add a test that checks argument passing via the stack.