const initialization: a few fixes (#2158)

* const initialization: a few fixes

* cargo fmt

* Address review comments

* Add IR test

Co-authored-by: Mohammad Fawaz <[email protected]>

Author: vaivaswatha

sway-core/src/ir_generation/function.rs

@@ -9,6 +9,7 @@ use crate::{
     asm_generation::from_ir::ir_type_size_in_bytes,
     constants,
     error::CompileError,
+    ir_generation::const_eval::compile_constant_expression,
     parse_tree::{AsmOp, AsmRegister, LazyOp, Literal, Purity, Visibility},
     semantic_analysis::*,
     type_engine::{insert_type, resolve_type, TypeId, TypeInfo},
@@ -997,29 +998,33 @@ impl FnCompiler {
         // This is local to the function, so we add it to the locals, rather than the module
         // globals like other const decls.
         let TypedConstantDeclaration { name, value, .. } = ast_const_decl;
+        let const_expr_val = compile_constant_expression(context, self.module, &value)?;
+        let local_name = self.lexical_map.insert(name.as_str().to_owned());
+        let return_type = convert_resolved_typeid(context, &value.return_type, &value.span)?;
 
-        if let TypedExpressionVariant::Literal(literal) = &value.expression {
-            let initialiser = convert_literal_to_constant(literal);
-            let return_type = convert_resolved_typeid(context, &value.return_type, &value.span)?;
-            let name = name.as_str().to_owned();
-            self.function
-                .new_local_ptr(context, name.clone(), return_type, false, Some(initialiser))
-                .map_err(|ir_error| {
-                    CompileError::InternalOwned(ir_error.to_string(), Span::dummy())
-                })?;
-
-            // We still insert this into the symbol table, as itself... can they be shadowed?
-            // (Hrmm, name resolution in the variable expression code could be smarter about var
-            // decls vs const decls, for now they're essentially the same...)
-            self.lexical_map.insert(name);
+        // We compile consts the same as vars are compiled. This is because ASM generation
+        // cannot handle
+        //    1. initializing aggregates
+        //    2. get_ptr()
+        // into the data section.
+        let ptr = self
+            .function
+            .new_local_ptr(context, local_name, return_type, false, None)
+            .map_err(|ir_error| CompileError::InternalOwned(ir_error.to_string(), Span::dummy()))?;
 
-            Ok(Constant::get_unit(context, span_md_idx))
-        } else {
-            Err(CompileError::Internal(
-                "Unsupported constant declaration type, expecting a literal.",
-                name.span(),
-            ))
+        // We can have empty aggregates, especially arrays, which shouldn't be initialised, but
+        // otherwise use a store.
+        let ptr_ty = *ptr.get_type(context);
+        if ir_type_size_in_bytes(context, &ptr_ty) > 0 {
+            let ptr_val = self
+                .current_block
+                .ins(context)
+                .get_ptr(ptr, ptr_ty, 0, span_md_idx);
+            self.current_block
+                .ins(context)
+                .store(ptr_val, const_expr_val, span_md_idx);
         }
+        Ok(const_expr_val)
     }
 
     fn compile_reassignment(

sway-core/src/semantic_analysis/ast_node/expression/typed_expression/method_application.rs

@@ -193,14 +193,21 @@ pub(crate) fn type_check_method_application(
             warnings,
             errors
         );
-        let variable_decl = check!(
-            unknown_decl.expect_variable().cloned(),
-            return err(warnings, errors),
-            warnings,
-            errors
-        );
 
-        if !variable_decl.is_mutable.is_mutable() && *is_mutable {
+        let is_decl_mutable = match unknown_decl {
+            TypedDeclaration::ConstantDeclaration(_) => false,
+            _ => {
+                let variable_decl = check!(
+                    unknown_decl.expect_variable().cloned(),
+                    return err(warnings, errors),
+                    warnings,
+                    errors
+                );
+                variable_decl.is_mutable.is_mutable()
+            }
+        };
+
+        if !is_decl_mutable && *is_mutable {
             errors.push(CompileError::MethodRequiresMutableSelf {
                 method_name: method_name.easy_name(),
                 variable_name: name.clone(),

sway-core/src/semantic_analysis/ast_node/mod.rs

@@ -303,25 +303,16 @@ impl TypedAstNode {
                             value,
                             visibility,
                         }) => {
-                            let result = type_check_ascribed_expr(
-                                ctx.by_ref(),
-                                type_ascription.clone(),
-                                value,
-                            );
+                            let result =
+                                type_check_ascribed_expr(ctx.by_ref(), type_ascription, value);
                             is_screaming_snake_case(&name).ok(&mut warnings, &mut errors);
                             let value =
                                 check!(result, error_recovery_expr(name.span()), warnings, errors);
                             let typed_const_decl =
-                                TypedDeclaration::VariableDeclaration(TypedVariableDeclaration {
+                                TypedDeclaration::ConstantDeclaration(TypedConstantDeclaration {
                                     name: name.clone(),
-                                    body: value,
-                                    is_mutable: if visibility.is_public() {
-                                        VariableMutability::ExportedConst
-                                    } else {
-                                        VariableMutability::Immutable
-                                    },
-                                    const_decl_origin: true,
-                                    type_ascription: insert_type(type_ascription),
+                                    value,
+                                    visibility,
                                 });
                             ctx.namespace.insert_symbol(name, typed_const_decl.clone());
                             typed_const_decl

sway-core/tests/sway_to_ir/local_const_init.ir

@@ -0,0 +1,20 @@
+script {
+    fn main() -> u64, !1 {
+        local ptr { u64 } X
+
+        entry:
+        v0 = get_ptr ptr { u64 } X, ptr { u64 }, 0, !2
+        v1 = const { u64 } { u64 1 }, !3
+        store v1, ptr v0, !2
+        v2 = get_ptr ptr { u64 } X, ptr { u64 }, 0, !4
+        v3 = extract_value v2, { u64 }, 0, !5
+        ret u64 v3
+    }
+}
+
+!0 = filepath "/path/to/local_const_init.sw"
+!1 = span !0 70 114
+!2 = span !0 91 106
+!3 = span !0 33 68
+!4 = span !0 109 110
+!5 = span !0 22 29

sway-core/tests/sway_to_ir/local_const_init.sw

@@ -0,0 +1,14 @@
+script;
+
+struct S {
+  s : u64
+}
+
+fn s(x : u64) -> S {
+  S { s: x }
+}
+
+fn main() -> u64 {
+  const X = s(1);
+  X.s
+}

test/src/e2e_vm_tests/test_programs/should_fail/const_nonconst_init/Forc.lock

@@ -0,0 +1,9 @@
+[[package]]
+name = 'const_nonconst_init'
+source = 'root'
+dependencies = ['core']
+
+[[package]]
+name = 'core'
+source = 'path+from-root-E57A3612ABF8CF11'
+dependencies = []

test/src/e2e_vm_tests/test_programs/should_fail/const_nonconst_init/Forc.toml

@@ -0,0 +1,8 @@
+[project]
+authors = ["Fuel Labs <[email protected]>"]
+entry = "main.sw"
+license = "Apache-2.0"
+name = "const_nonconst_init"
+
+[dependencies]
+core = { path = "../../../../../../sway-lib-core" }

test/src/e2e_vm_tests/test_programs/should_fail/const_nonconst_init/src/main.sw

@@ -0,0 +1,10 @@
+script;
+
+fn bla(x: u64) -> u64 {
+    x + 1
+}
+
+fn main() -> u64 {
+    const X = bla(0);
+    X
+}

test/src/e2e_vm_tests/test_programs/should_fail/const_nonconst_init/test.toml

@@ -0,0 +1,4 @@
+category = "fail"
+
+# check: $()const X = bla(0);
+# nextln: $()Could not evaluate initializer to a const declaration.

test/src/e2e_vm_tests/test_programs/should_pass/language/const_inits/src/main.sw

@@ -36,17 +36,22 @@ const EN1c = En1::NoVal;
 const ETH_ID0_VALUE = ETH_ID0.value;
 const TUP1_idx2 = TUP1.2;
 
+const INT1 = 1;
+
 fn main() -> u64 {
+    const int1 = 1;
+    assert(int1 == INT1);
+
     // initialization through function applications.
-    let eth_id0 = ~ContractId::from(0x0000000000000000000000000000000000000000000000000000000000000000);
-    let eth_id1 = ~ContractId::from(0x0000000000000000000000000000000000000000000000000000000000000001);
+    const eth_id0 = ~ContractId::from(0x0000000000000000000000000000000000000000000000000000000000000000);
+    const eth_id1 = ~ContractId::from(0x0000000000000000000000000000000000000000000000000000000000000001);
     assert(eth_id0 == ETH_ID0 && eth_id1 == ETH_ID1);
 
     // tuples and arrays.
-    let t1 = (2, 1, 21);
+    const t1 = (2, 1, 21);
     assert(t1.0 == TUP1.0 && t1.1 == TUP1.1 && t1.2 == TUP1.2);
     assert(t1.0 == TUP2.0 && t1.1 == TUP2.1 && t1.2 == TUP2.2);
-    let a1 = [1, 2, 3];
+    const a1 = [1, 2, 3];
     assert(a1[0] == ARR1[0] && a1[1] == ARR1[1] && a1[2] == ARR1[2]);
     assert(a1[0] == ARR2[0] && a1[1] == ARR2[1] && a1[2] == ARR2[2]);