Merge pull request #539 from rtfeldman/num-add-wrap-check

Addition variants

BUILDING_FROM_SOURCE.md

@@ -36,7 +36,7 @@ $ brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/6616d50f
 $ brew pin llvm
 ```
 
-If that doesn't work and you get a `brew` error `Error: Calling Installation of llvm from a GitHub commit URL is disabled! Use 'brew extract llvm' to stable tap on GitHub instead.` while trying the above solution, you can follow the steps extracting the formular into your private tap (one public version is at `sladwig/tap/llvm`). If installing LLVM still fails, it might help to run `sudo xcode-select -r` before installing again.
+If that doesn't work and you get a `brew` error `Error: Calling Installation of llvm from a GitHub commit URL is disabled! Use 'brew extract llvm' to stable tap on GitHub instead.` while trying the above solution, you can follow the steps extracting the formula into your private tap (one public version is at `sladwig/tap/llvm`). If installing LLVM still fails, it might help to run `sudo xcode-select -r` before installing again.
 
 ### LLVM installation on Windows
 

cli/src/lib.rs

@@ -210,6 +210,12 @@ fn build_file(
             "host.rs",
             "-o",
             binary_path.as_path().to_str().unwrap(),
+            // ensure we don't make a position-independent executable
+            "-C",
+            "link-arg=-no-pie",
+            // explicitly link in the c++ stdlib, for exceptions
+            "-C",
+            "link-arg=-lc++",
         ])
         .current_dir(cwd)
         .spawn()

compiler/builtins/bitcode/src/lib.rs

@@ -36,3 +36,12 @@ pub fn pow_int_(mut base: i64, mut exp: i64) -> i64 {
 
     acc
 }
+
+/// Adapted from Rust's core::num module, by the Rust core team,
+/// licensed under the Apache License, version 2.0 - https://www.apache.org/licenses/LICENSE-2.0
+///
+/// Thank you, Rust core team!
+#[no_mangle]
+pub fn is_finite_(num: f64) -> bool {
+    f64::is_finite(num)
+}

compiler/builtins/src/std.rs

@@ -187,6 +187,26 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         ),
     );
 
+    // addChecked : Num a, Num a -> Result (Num a) [ IntOverflow ]*
+    let overflow = SolvedType::TagUnion(
+        vec![(TagName::Global("Overflow".into()), vec![])],
+        Box::new(SolvedType::Wildcard),
+    );
+
+    add_type(
+        Symbol::NUM_ADD_CHECKED,
+        SolvedType::Func(
+            vec![num_type(flex(TVAR1)), num_type(flex(TVAR1))],
+            Box::new(result_type(num_type(flex(TVAR1)), overflow)),
+        ),
+    );
+
+    // addWrap : Int, Int -> Int
+    add_type(
+        Symbol::NUM_ADD_WRAP,
+        SolvedType::Func(vec![int_type(), int_type()], Box::new(int_type())),
+    );
+
     // sub or (-) : Num a, Num a -> Num a
     add_type(
         Symbol::NUM_SUB,

compiler/builtins/src/unique.rs

@@ -274,6 +274,26 @@ pub fn types() -> MutMap<Symbol, (SolvedType, Region)> {
         unique_function(vec![num_type(u, num), num_type(v, num)], num_type(w, num))
     });
 
+    // addChecked : Num a, Num a -> Result (Num a) [ IntOverflow ]*
+    let overflow = SolvedType::TagUnion(
+        vec![(TagName::Global("Overflow".into()), vec![])],
+        Box::new(SolvedType::Wildcard),
+    );
+
+    add_type(Symbol::NUM_ADD_CHECKED, {
+        let_tvars! { u, v, w, num, result, star };
+        unique_function(
+            vec![num_type(u, num), num_type(v, num)],
+            result_type(result, num_type(w, num), lift(star, overflow)),
+        )
+    });
+
+    // addWrap : Int, Int -> Int
+    add_type(Symbol::NUM_ADD_WRAP, {
+        let_tvars! { u, v, w };
+        unique_function(vec![int_type(u), int_type(v)], int_type(w))
+    });
+
     // sub or (-) : Num a, Num a -> Num a
     add_type(Symbol::NUM_SUB, {
         let_tvars! { u, v, w, num };

compiler/can/src/builtins.rs

@@ -68,6 +68,8 @@ pub fn builtin_defs(var_store: &mut VarStore) -> MutMap<Symbol, Def> {
         Symbol::LIST_KEEP_IF => list_keep_if,
         Symbol::LIST_WALK_RIGHT => list_walk_right,
         Symbol::NUM_ADD => num_add,
+        Symbol::NUM_ADD_CHECKED => num_add_checked,
+        Symbol::NUM_ADD_WRAP => num_add_wrap,
         Symbol::NUM_SUB => num_sub,
         Symbol::NUM_MUL => num_mul,
         Symbol::NUM_GT => num_gt,
@@ -238,6 +240,105 @@ fn num_add(symbol: Symbol, var_store: &mut VarStore) -> Def {
     num_binop(symbol, var_store, LowLevel::NumAdd)
 }
 
+/// Num.add : Num a, Num a -> Num a
+fn num_add_wrap(symbol: Symbol, var_store: &mut VarStore) -> Def {
+    num_binop(symbol, var_store, LowLevel::NumAddWrap)
+}
+
+/// Num.add : Num a, Num a -> Num a
+fn num_add_checked(symbol: Symbol, var_store: &mut VarStore) -> Def {
+    let bool_var = var_store.fresh();
+    let num_var_1 = var_store.fresh();
+    let num_var_2 = var_store.fresh();
+    let num_var_3 = var_store.fresh();
+    let ret_var = var_store.fresh();
+    let record_var = var_store.fresh();
+
+    // let arg_3 = RunLowLevel NumAddChecked arg_1 arg_2
+    //
+    // if arg_3.b then
+    //  # overflow
+    //  Err Overflow
+    // else
+    //  # all is well
+    //  Ok arg_3.a
+
+    let cont = If {
+        branch_var: ret_var,
+        cond_var: bool_var,
+        branches: vec![(
+            // if-condition
+            no_region(
+                // arg_3.b
+                Access {
+                    record_var,
+                    ext_var: var_store.fresh(),
+                    field: "b".into(),
+                    field_var: var_store.fresh(),
+                    loc_expr: Box::new(no_region(Var(Symbol::ARG_3))),
+                },
+            ),
+            // overflow!
+            no_region(tag(
+                "Err",
+                vec![tag("Overflow", Vec::new(), var_store)],
+                var_store,
+            )),
+        )],
+        final_else: Box::new(
+            // all is well
+            no_region(
+                // Ok arg_3.a
+                tag(
+                    "Ok",
+                    vec![
+                        // arg_3.a
+                        Access {
+                            record_var,
+                            ext_var: var_store.fresh(),
+                            field: "a".into(),
+                            field_var: num_var_3,
+                            loc_expr: Box::new(no_region(Var(Symbol::ARG_3))),
+                        },
+                    ],
+                    var_store,
+                ),
+            ),
+        ),
+    };
+
+    // arg_3 = RunLowLevel NumAddChecked arg_1 arg_2
+    let def = crate::def::Def {
+        loc_pattern: no_region(Pattern::Identifier(Symbol::ARG_3)),
+        loc_expr: no_region(RunLowLevel {
+            op: LowLevel::NumAddChecked,
+            args: vec![
+                (num_var_1, Var(Symbol::ARG_1)),
+                (num_var_2, Var(Symbol::ARG_2)),
+            ],
+            ret_var: record_var,
+        }),
+        expr_var: record_var,
+        pattern_vars: SendMap::default(),
+        annotation: None,
+    };
+
+    let body = LetNonRec(
+        Box::new(def),
+        Box::new(no_region(cont)),
+        ret_var,
+        SendMap::default(),
+    );
+
+    defn(
+        symbol,
+        vec![(num_var_1, Symbol::ARG_1), (num_var_2, Symbol::ARG_2)],
+        var_store,
+        body,
+        ret_var,
+    )
+}
+
 /// Num.sub : Num a, Num a -> Num a
 fn num_sub(symbol: Symbol, var_store: &mut VarStore) -> Def {
     num_binop(symbol, var_store, LowLevel::NumSub)

compiler/gen/src/llvm/build.rs

@@ -270,6 +270,12 @@ fn add_intrinsics<'ctx>(ctx: &'ctx Context, module: &Module<'ctx>) {
         LLVM_FLOOR_F64,
         f64_type.fn_type(&[f64_type.into()], false),
     );
+
+    add_intrinsic(module, LLVM_SADD_WITH_OVERFLOW_I64, {
+        let fields = [i64_type.into(), i1_type.into()];
+        ctx.struct_type(&fields, false)
+            .fn_type(&[i64_type.into(), i64_type.into()], false)
+    });
 }
 
 static LLVM_MEMSET_I64: &str = "llvm.memset.p0i8.i64";
@@ -282,6 +288,7 @@ static LLVM_COS_F64: &str = "llvm.cos.f64";
 static LLVM_POW_F64: &str = "llvm.pow.f64";
 static LLVM_CEILING_F64: &str = "llvm.ceil.f64";
 static LLVM_FLOOR_F64: &str = "llvm.floor.f64";
+static LLVM_SADD_WITH_OVERFLOW_I64: &str = "llvm.sadd.with.overflow.i64";
 
 fn add_intrinsic<'ctx>(
     module: &Module<'ctx>,
@@ -940,8 +947,6 @@ pub fn build_exp_expr<'a, 'ctx, 'env>(
             debug_assert!(*union_size > 1);
             let ptr_size = env.ptr_bytes;
 
-            let mut filler = tag_layout.stack_size(ptr_size);
-
             let ctx = env.context;
             let builder = env.builder;
 
@@ -978,16 +983,9 @@ pub fn build_exp_expr<'a, 'ctx, 'env>(
                     } else {
                         field_vals.push(val);
                     }
-
-                    filler -= field_size;
                 }
             }
 
-            // TODO verify that this is required (better safe than sorry)
-            if filler > 0 {
-                field_types.push(env.context.i8_type().array_type(filler).into());
-            }
-
             // Create the struct_type
             let struct_type = ctx.struct_type(field_types.into_bump_slice(), false);
             let mut struct_val = struct_type.const_zero().into();
@@ -2108,7 +2106,7 @@ fn run_low_level<'a, 'ctx, 'env>(
             list_join(env, inplace, parent, list, outer_list_layout)
         }
         NumAbs | NumNeg | NumRound | NumSqrtUnchecked | NumSin | NumCos | NumCeiling | NumFloor
-        | NumToFloat => {
+        | NumToFloat | NumIsFinite => {
             debug_assert_eq!(args.len(), 1);
 
             let (arg, arg_layout) = load_symbol_and_layout(env, scope, &args[0]);
@@ -2219,7 +2217,7 @@ fn run_low_level<'a, 'ctx, 'env>(
         }
 
         NumAdd | NumSub | NumMul | NumLt | NumLte | NumGt | NumGte | NumRemUnchecked
-        | NumDivUnchecked | NumPow | NumPowInt => {
+        | NumAddWrap | NumAddChecked | NumDivUnchecked | NumPow | NumPowInt => {
             debug_assert_eq!(args.len(), 2);
 
             let (lhs_arg, lhs_layout) = load_symbol_and_layout(env, scope, &args[0]);
@@ -2234,6 +2232,7 @@ fn run_low_level<'a, 'ctx, 'env>(
                     match lhs_builtin {
                         Int128 | Int64 | Int32 | Int16 | Int8 => build_int_binop(
                             env,
+                            parent,
                             lhs_arg.into_int_value(),
                             lhs_layout,
                             rhs_arg.into_int_value(),
@@ -2242,6 +2241,7 @@ fn run_low_level<'a, 'ctx, 'env>(
                         ),
                         Float128 | Float64 | Float32 | Float16 => build_float_binop(
                             env,
+                            parent,
                             lhs_arg.into_float_value(),
                             lhs_layout,
                             rhs_arg.into_float_value(),
@@ -2413,6 +2413,7 @@ where
 
 fn build_int_binop<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
+    parent: FunctionValue<'ctx>,
     lhs: IntValue<'ctx>,
     _lhs_layout: &Layout<'a>,
     rhs: IntValue<'ctx>,
@@ -2425,7 +2426,37 @@ fn build_int_binop<'a, 'ctx, 'env>(
     let bd = env.builder;
 
     match op {
-        NumAdd => bd.build_int_add(lhs, rhs, "add_int").into(),
+        NumAdd => {
+            let context = env.context;
+            let result = env
+                .call_intrinsic(LLVM_SADD_WITH_OVERFLOW_I64, &[lhs.into(), rhs.into()])
+                .into_struct_value();
+
+            let add_result = bd.build_extract_value(result, 0, "add_result").unwrap();
+            let has_overflowed = bd.build_extract_value(result, 1, "has_overflowed").unwrap();
+
+            let condition = bd.build_int_compare(
+                IntPredicate::EQ,
+                has_overflowed.into_int_value(),
+                context.bool_type().const_zero(),
+                "has_not_overflowed",
+            );
+
+            let then_block = context.append_basic_block(parent, "then_block");
+            let throw_block = context.append_basic_block(parent, "throw_block");
+
+            bd.build_conditional_branch(condition, then_block, throw_block);
+
+            bd.position_at_end(throw_block);
+
+            throw_exception(env, "integer addition overflowed!");
+
+            bd.position_at_end(then_block);
+
+            add_result
+        }
+        NumAddWrap => bd.build_int_add(lhs, rhs, "add_int_wrap").into(),
+        NumAddChecked => env.call_intrinsic(LLVM_SADD_WITH_OVERFLOW_I64, &[lhs.into(), rhs.into()]),
         NumSub => bd.build_int_sub(lhs, rhs, "sub_int").into(),
         NumMul => bd.build_int_mul(lhs, rhs, "mul_int").into(),
         NumGt => bd.build_int_compare(SGT, lhs, rhs, "int_gt").into(),
@@ -2462,6 +2493,7 @@ fn call_bitcode_fn<'a, 'ctx, 'env>(
 
 fn build_float_binop<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
+    parent: FunctionValue<'ctx>,
     lhs: FloatValue<'ctx>,
     _lhs_layout: &Layout<'a>,
     rhs: FloatValue<'ctx>,
@@ -2474,7 +2506,55 @@ fn build_float_binop<'a, 'ctx, 'env>(
     let bd = env.builder;
 
     match op {
-        NumAdd => bd.build_float_add(lhs, rhs, "add_float").into(),
+        NumAdd => {
+            let builder = env.builder;
+            let context = env.context;
+
+            let result = bd.build_float_add(lhs, rhs, "add_float");
+
+            let is_finite =
+                call_bitcode_fn(NumIsFinite, env, &[result.into()], "is_finite_").into_int_value();
+
+            let then_block = context.append_basic_block(parent, "then_block");
+            let throw_block = context.append_basic_block(parent, "throw_block");
+
+            builder.build_conditional_branch(is_finite, then_block, throw_block);
+
+            builder.position_at_end(throw_block);
+
+            throw_exception(env, "float addition overflowed!");
+
+            builder.position_at_end(then_block);
+
+            result.into()
+        }
+        NumAddChecked => {
+            let context = env.context;
+
+            let result = bd.build_float_add(lhs, rhs, "add_float");
+
+            let is_finite =
+                call_bitcode_fn(NumIsFinite, env, &[result.into()], "is_finite_").into_int_value();
+            let is_infinite = bd.build_not(is_finite, "negate");
+
+            let struct_type = context.struct_type(
+                &[context.f64_type().into(), context.bool_type().into()],
+                false,
+            );
+
+            let struct_value = {
+                let v1 = struct_type.const_zero();
+                let v2 = bd.build_insert_value(v1, result, 0, "set_result").unwrap();
+                let v3 = bd
+                    .build_insert_value(v2, is_infinite, 1, "set_is_infinite")
+                    .unwrap();
+
+                v3.into_struct_value()
+            };
+
+            struct_value.into()
+        }
+        NumAddWrap => unreachable!("wrapping addition is not defined on floats"),
         NumSub => bd.build_float_sub(lhs, rhs, "sub_float").into(),
         NumMul => bd.build_float_mul(lhs, rhs, "mul_float").into(),
         NumGt => bd.build_float_compare(OGT, lhs, rhs, "float_gt").into(),
@@ -2578,6 +2658,7 @@ fn build_float_unary_op<'a, 'ctx, 'env>(
             env.context.i64_type(),
             "num_floor",
         ),
+        NumIsFinite => call_bitcode_fn(NumIsFinite, env, &[arg.into()], "is_finite_"),
         _ => {
             unreachable!("Unrecognized int unary operation: {:?}", op);
         }
@@ -2588,7 +2669,6 @@ fn define_global_str<'a, 'ctx, 'env>(
     env: &Env<'a, 'ctx, 'env>,
     message: &str,
 ) -> inkwell::values::GlobalValue<'ctx> {
-    let context = env.context;
     let module = env.module;
 
     // hash the name so we don't re-define existing messages
@@ -2600,29 +2680,12 @@ fn define_global_str<'a, 'ctx, 'env>(
         message.hash(&mut hasher);
         let hash = hasher.finish();
 
-        format!("message_{}", hash)
+        format!("_Error_message_{}", hash)
     };
 
     match module.get_global(&name) {
         Some(current) => current,
-        None => {
+        None => unsafe { env.builder.build_global_string(message, name.as_str()) },
-            let i8_type = context.i8_type();
-
-            // define the error message as a global constant
-            let message_global =
-                module.add_global(i8_type.array_type(message.len() as u32), None, &name);
-
-            let mut message_bytes = Vec::with_capacity_in(message.len(), env.arena);
-
-            for c in message.chars() {
-                message_bytes.push(i8_type.const_int(c as u64, false));
-            }
-
-            let const_array = i8_type.const_array(&message_bytes);
-            message_global.set_initializer(&const_array);
-
-            message_global
-        }
     }
 }
 

compiler/gen/tests/gen_num.rs

@@ -685,4 +685,102 @@ mod gen_num {
     fn pow_int() {
         assert_evals_to!("Num.powInt 2 3", 8, i64);
     }
+
+    #[test]
+    #[should_panic(expected = r#"Roc failed with message: "integer addition overflowed!"#)]
+    fn int_overflow() {
+        assert_evals_to!(
+            indoc!(
+                r#"
+                9_223_372_036_854_775_807 + 1
+                "#
+            ),
+            0,
+            i64
+        );
+    }
+
+    #[test]
+    fn int_add_checked() {
+        assert_evals_to!(
+            indoc!(
+                r#"
+                when Num.addChecked 1 2 is
+                    Ok v -> v
+                    _ -> -1
+                "#
+            ),
+            3,
+            i64
+        );
+
+        assert_evals_to!(
+            indoc!(
+                r#"
+                when Num.addChecked 9_223_372_036_854_775_807 1 is
+                    Err Overflow -> -1
+                    Ok v -> v
+                "#
+            ),
+            -1,
+            i64
+        );
+    }
+
+    #[test]
+    fn int_add_wrap() {
+        assert_evals_to!(
+            indoc!(
+                r#"
+                Num.addWrap 9_223_372_036_854_775_807 1
+                "#
+            ),
+            std::i64::MIN,
+            i64
+        );
+    }
+
+    #[test]
+    fn float_add_checked_pass() {
+        assert_evals_to!(
+            indoc!(
+                r#"
+                when Num.addChecked 1.0 0.0 is 
+                    Ok v -> v
+                    Err Overflow -> -1.0
+                "#
+            ),
+            1.0,
+            f64
+        );
+    }
+
+    #[test]
+    fn float_add_checked_fail() {
+        assert_evals_to!(
+            indoc!(
+                r#"
+                when Num.addChecked 1.7976931348623157e308 1.7976931348623157e308 is
+                    Err Overflow -> -1
+                    Ok v -> v
+                "#
+            ),
+            -1.0,
+            f64
+        );
+    }
+
+    #[test]
+    #[should_panic(expected = r#"Roc failed with message: "float addition overflowed!"#)]
+    fn float_overflow() {
+        assert_evals_to!(
+            indoc!(
+                r#"
+                1.7976931348623157e308 + 1.7976931348623157e308
+                "#
+            ),
+            0.0,
+            f64
+        );
+    }
 }

compiler/module/src/low_level.rs

@@ -20,6 +20,8 @@ pub enum LowLevel {
     ListKeepIf,
     ListWalkRight,
     NumAdd,
+    NumAddWrap,
+    NumAddChecked,
     NumSub,
     NumMul,
     NumGt,
@@ -40,6 +42,7 @@ pub enum LowLevel {
     NumCeiling,
     NumPowInt,
     NumFloor,
+    NumIsFinite,
     Eq,
     NotEq,
     And,

compiler/module/src/symbol.rs

@@ -644,6 +644,8 @@ define_builtins! {
         39 NUM_CEILING: "ceiling"
         40 NUM_POW_INT: "powInt"
         41 NUM_FLOOR: "floor"
+        42 NUM_ADD_WRAP: "addWrap"
+        43 NUM_ADD_CHECKED: "addChecked"
     }
     2 BOOL: "Bool" => {
         0 BOOL_BOOL: "Bool" imported // the Bool.Bool type alias

compiler/mono/src/borrow.rs

@@ -521,12 +521,11 @@ pub fn lowlevel_borrow_signature(arena: &Bump, op: LowLevel) -> &[bool] {
         ListKeepIf => arena.alloc_slice_copy(&[owned, irrelevant]),
         ListWalkRight => arena.alloc_slice_copy(&[borrowed, irrelevant, owned]),
 
-        Eq | NotEq | And | Or | NumAdd | NumSub | NumMul | NumGt | NumGte | NumLt | NumLte
+        Eq | NotEq | And | Or | NumAdd | NumAddWrap | NumAddChecked | NumSub | NumMul | NumGt
-        | NumCompare | NumDivUnchecked | NumRemUnchecked | NumPow | NumPowInt => {
+        | NumGte | NumLt | NumLte | NumCompare | NumDivUnchecked | NumRemUnchecked | NumPow
-            arena.alloc_slice_copy(&[irrelevant, irrelevant])
+        | NumPowInt => arena.alloc_slice_copy(&[irrelevant, irrelevant]),
-        }
 
         NumAbs | NumNeg | NumSin | NumCos | NumSqrtUnchecked | NumRound | NumCeiling | NumFloor
-        | NumToFloat | Not => arena.alloc_slice_copy(&[irrelevant]),
+        | NumToFloat | Not | NumIsFinite => arena.alloc_slice_copy(&[irrelevant]),
     }
 }