Merge pull request #783 from taichi-ishitani/enhance_case_statement_e…

…xpression

Enhance case statement/expression

crates/analyzer/src/analyzer_error.rs

@@ -323,6 +323,20 @@ pub enum AnalyzerError {
         error_location: SourceSpan,
     },
 
+    #[diagnostic(
+        severity(Error),
+        code(invalid_case_condition_non_elaborative),
+        help(""),
+        url("")
+    )]
+    #[error("Case condition value cannot be used because it is not evaluable at elaboration time")]
+    InvalidCaseConditionNonElaborative {
+        #[source_code]
+        input: NamedSource,
+        #[label("Error location")]
+        error_location: SourceSpan,
+    },
+
     #[diagnostic(
         severity(Error),
         code(missing_default_argument),
@@ -1010,6 +1024,13 @@ impl AnalyzerError {
         }
     }
 
+    pub fn invalid_case_condition_non_elaborative(source: &str, token: &TokenRange) -> Self {
+        AnalyzerError::InvalidCaseConditionNonElaborative {
+            input: AnalyzerError::named_source(source, token),
+            error_location: token.into(),
+        }
+    }
+
     pub fn invalid_modport_variable_item(
         identifier: &str,
         source: &str,

crates/analyzer/src/evaluator.rs

@@ -650,6 +650,7 @@ impl Evaluator {
             }
             Factor::IfExpression(x) => self.if_expression(&x.if_expression),
             Factor::CaseExpression(x) => self.case_expression(&x.case_expression),
+            Factor::SwitchExpression(x) => self.switch_expression(&x.switch_expression),
             Factor::StringLiteral(_) => Evaluated::Unknown,
             Factor::FactorGroup(_) => Evaluated::Unknown,
             Factor::InsideExpression(_) => Evaluated::Unknown,
@@ -787,4 +788,8 @@ impl Evaluator {
     fn case_expression(&mut self, _arg: &CaseExpression) -> Evaluated {
         Evaluated::Unknown
     }
+
+    fn switch_expression(&mut self, _arg: &SwitchExpression) -> Evaluated {
+        Evaluated::Unknown
+    }
 }

crates/analyzer/src/handlers/check_expression.rs

@@ -1,4 +1,5 @@
 use crate::analyzer_error::AnalyzerError;
+use crate::evaluator::{Evaluated, Evaluator};
 use crate::symbol::SymbolKind;
 use crate::symbol_table;
 use veryl_parser::veryl_grammar_trait::*;
@@ -11,6 +12,8 @@ pub struct CheckExpression<'a> {
     pub errors: Vec<AnalyzerError>,
     text: &'a str,
     point: HandlerPoint,
+    case_condition_depth: usize,
+    evaluator: Evaluator,
 }
 
 impl<'a> CheckExpression<'a> {
@@ -29,6 +32,30 @@ impl<'a> Handler for CheckExpression<'a> {
 }
 
 impl<'a> VerylGrammarTrait for CheckExpression<'a> {
+    fn case_condition(&mut self, _arg: &CaseCondition) -> Result<(), ParolError> {
+        match self.point {
+            HandlerPoint::Before => self.case_condition_depth += 1,
+            HandlerPoint::After => self.case_condition_depth -= 1,
+        }
+        Ok(())
+    }
+
+    fn expression(&mut self, arg: &Expression) -> Result<(), ParolError> {
+        if let HandlerPoint::Before = self.point {
+            if self.case_condition_depth >= 1 {
+                let result = matches!(self.evaluator.expression(arg), Evaluated::Variable { .. });
+                if result {
+                    self.errors
+                        .push(AnalyzerError::invalid_case_condition_non_elaborative(
+                            self.text,
+                            &arg.into(),
+                        ));
+                }
+            }
+        }
+        Ok(())
+    }
+
     fn factor(&mut self, arg: &Factor) -> Result<(), ParolError> {
         if let HandlerPoint::Before = self.point {
             if let Factor::ExpressionIdentifierFactorOpt(x) = arg {

crates/analyzer/src/tests.rs

@@ -1643,24 +1643,147 @@ fn enum_non_const_exception() {
         i_clk: input clock,
         i_rst: input reset,
     ) {
-    
+
         enum State: logic<3> {
             Idle = 3'bxx1,
             Run0 = 3'b000,
             Run1 = 3'b010,
             Run2 = 3'b100,
             Done = 3'b110,
         }
-    
+
         var state: State;
-    
+
         always_ff {
             if_reset {
                 state = State::Idle;
             }
         }
-    
+
     }"#;
     let errors = analyze(code);
     assert!(errors.is_empty());
 }
+
+#[test]
+fn invalid_case_condition_expression() {
+    let code = r#"
+    module ModuleA (
+        i_sel: input  logic<3>,
+        i_a  : input  logic<4>,
+        o_b  : output logic,
+        o_c  : output logic,
+    ) {
+        local ONE: bit <3> = 3'd1;
+
+        always_comb {
+          case i_sel {
+            3'd0   : o_b = i_a[0];
+            ONE    : o_b = i_a[1];
+            2..=3  : o_b = i_a[2];
+            3'b1xx : o_b = i_a[3];
+            default: o_b = i_a[3];
+          }
+        }
+
+        assign o_c = case i_sel {
+            3'd0   : i_a[0],
+            ONE    : i_a[1],
+            2..=3  : i_a[2],
+            3'b1xx : i_a[3],
+            default: i_a[3],
+        };
+    }
+    "#;
+
+    let errors = analyze(code);
+    assert!(errors.is_empty());
+
+    let code = r#"
+    module ModuleB (
+        i_sel: input  logic<2>,
+        i_a  : input  logic<3>,
+        o_b  : output logic,
+    ) {
+        let c: logic<2> = 2'd0;
+
+        always_comb {
+          case i_sel {
+            c      : o_b = i_a[0];
+            default: o_b = i_a[1];
+          }
+        }
+    }
+    "#;
+
+    let errors = analyze(code);
+    assert!(matches!(
+        errors[0],
+        AnalyzerError::InvalidCaseConditionNonElaborative { .. }
+    ));
+
+    let code = r#"
+    module ModuleC (
+        i_sel: input  logic<2>,
+        i_a  : input  logic<3>,
+        o_b  : output logic,
+    ) {
+        let c: logic<2> = 2'd1;
+
+        always_comb {
+          case i_sel {
+            0..=c  : o_b = i_a[0];
+            default: o_b = i_a[1];
+          }
+        }
+    }
+    "#;
+
+    let errors = analyze(code);
+    assert!(matches!(
+        errors[0],
+        AnalyzerError::InvalidCaseConditionNonElaborative { .. }
+    ));
+
+    let code = r#"
+    module ModuleD (
+        i_sel: input  logic<2>,
+        i_a  : input  logic<3>,
+        o_b  : output logic,
+    ) {
+        let c: logic<2> = 2'd0;
+
+        assign o_b = case i_sel {
+            c      : i_a[0],
+            default: i_a[1],
+        };
+    }
+    "#;
+
+    let errors = analyze(code);
+    assert!(matches!(
+        errors[0],
+        AnalyzerError::InvalidCaseConditionNonElaborative { .. }
+    ));
+
+    let code = r#"
+    module ModuleE (
+        i_sel: input  logic<2>,
+        i_a  : input  logic<3>,
+        o_b  : output logic,
+    ) {
+        let c: logic<2> = 2'd1;
+
+        assign o_b = case i_sel {
+            0..=c  : i_a[0],
+            default: i_a[1],
+        };
+    }
+    "#;
+
+    let errors = analyze(code);
+    assert!(matches!(
+        errors[0],
+        AnalyzerError::InvalidCaseConditionNonElaborative { .. }
+    ));
+}

crates/emitter/src/aligner.rs

@@ -660,12 +660,12 @@ impl VerylWalker for Aligner {
     fn case_item(&mut self, arg: &CaseItem) {
         self.aligns[align_kind::EXPRESSION].start_item();
         match &*arg.case_item_group {
-            CaseItemGroup::ExpressionCaseItemGroupList(x) => {
-                self.expression(&x.expression);
-                for x in &x.case_item_group_list {
+            CaseItemGroup::CaseCondition(x) => {
+                self.range_item(&x.case_condition.range_item);
+                for x in &x.case_condition.case_condition_list {
                     self.comma(&x.comma);
                     self.space(1);
-                    self.expression(&x.expression);
+                    self.range_item(&x.range_item);
                 }
             }
             CaseItemGroup::Defaul(x) => self.defaul(&x.defaul),
@@ -684,6 +684,34 @@ impl VerylWalker for Aligner {
         }
     }
 
+    /// Semantic action for non-terminal 'SwitchItem'
+    fn switch_item(&mut self, arg: &SwitchItem) {
+        self.aligns[align_kind::EXPRESSION].start_item();
+        match &*arg.switch_item_group {
+            SwitchItemGroup::SwitchCondition(x) => {
+                self.expression(&x.switch_condition.expression);
+                for x in &x.switch_condition.switch_condition_list {
+                    self.comma(&x.comma);
+                    self.space(1);
+                    self.expression(&x.expression);
+                }
+            }
+            SwitchItemGroup::Defaul(x) => self.defaul(&x.defaul),
+        }
+        self.aligns[align_kind::EXPRESSION].finish_item();
+        self.colon(&arg.colon);
+        match &*arg.switch_item_group0 {
+            SwitchItemGroup0::Statement(x) => self.statement(&x.statement),
+            SwitchItemGroup0::LBraceSwitchItemGroup0ListRBrace(x) => {
+                self.l_brace(&x.l_brace);
+                for x in &x.switch_item_group0_list {
+                    self.statement(&x.statement);
+                }
+                self.r_brace(&x.r_brace);
+            }
+        }
+    }
+
     /// Semantic action for non-terminal 'LetDeclaration'
     fn let_declaration(&mut self, arg: &LetDeclaration) {
         self.r#let(&arg.r#let);