From 8447544e17cbc5ec5dbbf6ac508636b8dc325de1 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Fri, 24 Nov 2023 09:50:11 +0100
Subject: [PATCH] LibJS/JIT: Add builtin for Math.round()

---
 Userland/Libraries/LibJS/Bytecode/Builtins.h    |  1 +
 Userland/Libraries/LibJS/JIT/Compiler.cpp       | 13 +++++++++++++
 Userland/Libraries/LibJS/Runtime/MathObject.cpp | 12 +++++++++---
 Userland/Libraries/LibJS/Runtime/MathObject.h   |  1 +
 4 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/Userland/Libraries/LibJS/Bytecode/Builtins.h b/Userland/Libraries/LibJS/Bytecode/Builtins.h
index 053a280504..d0c4f252db 100644
--- a/Userland/Libraries/LibJS/Bytecode/Builtins.h
+++ b/Userland/Libraries/LibJS/Bytecode/Builtins.h
@@ -18,6 +18,7 @@ namespace JS::Bytecode {
     O(MathPow, math_pow, Math, pow, 2)       \
     O(MathCeil, math_ceil, Math, ceil, 1)    \
     O(MathFloor, math_floor, Math, floor, 1) \
+    O(MathRound, math_round, Math, round, 1) \
     O(MathSqrt, math_sqrt, Math, sqrt, 1)
 
 enum class Builtin {
diff --git a/Userland/Libraries/LibJS/JIT/Compiler.cpp b/Userland/Libraries/LibJS/JIT/Compiler.cpp
index 69816679ae..2284be288c 100644
--- a/Userland/Libraries/LibJS/JIT/Compiler.cpp
+++ b/Userland/Libraries/LibJS/JIT/Compiler.cpp
@@ -2689,6 +2689,19 @@ void Compiler::compile_builtin_math_ceil(Assembler::Label&, Assembler::Label& en
     m_assembler.jump(end);
 }
 
+static Value cxx_math_round(VM& vm, Value, Value value)
+{
+    return TRY_OR_SET_EXCEPTION(MathObject::round_impl(vm, value));
+}
+
+void Compiler::compile_builtin_math_round(Assembler::Label&, Assembler::Label& end)
+{
+    native_call((void*)cxx_math_round);
+    store_accumulator(RET);
+    check_exception();
+    m_assembler.jump(end);
+}
+
 void Compiler::compile_builtin_math_abs(Assembler::Label& slow_case, Assembler::Label& end)
 {
     branch_if_int32(ARG2, [&] {
diff --git a/Userland/Libraries/LibJS/Runtime/MathObject.cpp b/Userland/Libraries/LibJS/Runtime/MathObject.cpp
index 6f551ba50b..6480a20aa7 100644
--- a/Userland/Libraries/LibJS/Runtime/MathObject.cpp
+++ b/Userland/Libraries/LibJS/Runtime/MathObject.cpp
@@ -34,7 +34,7 @@ void MathObject::initialize(Realm& realm)
     define_native_function(realm, vm.names.sqrt, sqrt, 1, attr, Bytecode::Builtin::MathSqrt);
     define_native_function(realm, vm.names.floor, floor, 1, attr, Bytecode::Builtin::MathFloor);
     define_native_function(realm, vm.names.ceil, ceil, 1, attr, Bytecode::Builtin::MathCeil);
-    define_native_function(realm, vm.names.round, round, 1, attr);
+    define_native_function(realm, vm.names.round, round, 1, attr, Bytecode::Builtin::MathRound);
     define_native_function(realm, vm.names.max, max, 2, attr);
     define_native_function(realm, vm.names.min, min, 2, attr);
     define_native_function(realm, vm.names.trunc, trunc, 1, attr);
@@ -770,10 +770,10 @@ JS_DEFINE_NATIVE_FUNCTION(MathObject::random)
 }
 
 // 21.3.2.28 Math.round ( x ), https://tc39.es/ecma262/#sec-math.round
-JS_DEFINE_NATIVE_FUNCTION(MathObject::round)
+ThrowCompletionOr<Value> MathObject::round_impl(VM& vm, Value x)
 {
     // 1. Let n be ? ToNumber(x).
-    auto number = TRY(vm.argument(0).to_number(vm));
+    auto number = TRY(x.to_number(vm));
 
     // 2. If n is not finite or n is an integral Number, return n.
     if (!number.is_finite_number() || number.as_double() == ::trunc(number.as_double()))
@@ -788,6 +788,12 @@ JS_DEFINE_NATIVE_FUNCTION(MathObject::round)
     return Value(integer);
 }
 
+// 21.3.2.28 Math.round ( x ), https://tc39.es/ecma262/#sec-math.round
+JS_DEFINE_NATIVE_FUNCTION(MathObject::round)
+{
+    return round_impl(vm, vm.argument(0));
+}
+
 // 21.3.2.29 Math.sign ( x ), https://tc39.es/ecma262/#sec-math.sign
 JS_DEFINE_NATIVE_FUNCTION(MathObject::sign)
 {
diff --git a/Userland/Libraries/LibJS/Runtime/MathObject.h b/Userland/Libraries/LibJS/Runtime/MathObject.h
index 5b44f545a5..5546f9fc61 100644
--- a/Userland/Libraries/LibJS/Runtime/MathObject.h
+++ b/Userland/Libraries/LibJS/Runtime/MathObject.h
@@ -23,6 +23,7 @@ public:
     static ThrowCompletionOr<Value> pow_impl(VM&, Value base, Value exponent);
     static ThrowCompletionOr<Value> floor_impl(VM&, Value);
     static ThrowCompletionOr<Value> ceil_impl(VM&, Value);
+    static ThrowCompletionOr<Value> round_impl(VM&, Value);
 
 private:
     explicit MathObject(Realm&);