fix(backend): Imm value exceeds range

src/ast/graph.rs

@@ -2,7 +2,7 @@ use petgraph::dot::{Config, Dot};
 use petgraph::graph::{Graph, NodeIndex};
 
 use crate::ast::types::{
-    BlockStmt, BreakStmt, CompileUnit, ContinueStmt, Expr, ExprValue, FuncDeclStmt, GlobalDeclStmt, IfStmt, Param, ReturnStmt, Statement, VarDeclStmt, VarDeclStmtValue, WhileStmt
+    ArrayDimension, BlockStmt, BreakStmt, CompileUnit, ContinueStmt, Expr, ExprValue, FuncDeclStmt, GlobalDeclStmt, IfStmt, Param, ReturnStmt, Statement, VarDeclStmt, VarDeclStmtValue, WhileStmt
 };
 
 pub type AstGraph = Graph<String, String>;
@@ -73,7 +73,19 @@ impl AstGraphBuilder {
     }
 
     fn add_var_decl_value(&mut self, parent: NodeIndex, value: &VarDeclStmtValue) -> NodeIndex {
-        self.child(parent, value.to_string())
+        let node = self.child(parent, value.to_string());
+        for dimension in &value.dimensions {
+            self.add_array_dimension(node, dimension);
+        }
+        node
+    }
+
+    fn add_array_dimension(&mut self, parent: NodeIndex, dimension: &ArrayDimension) -> NodeIndex {
+        let node = self.child(parent, dimension.to_string());
+        if let Some(value) = &dimension.value {
+            self.add_expr(node, value);
+        }
+        node
     }
 
     fn add_func_decl(&mut self, parent: NodeIndex, func_decl: &FuncDeclStmt) -> NodeIndex {
@@ -87,7 +99,11 @@ impl AstGraphBuilder {
     }
 
     fn add_param(&mut self, parent: NodeIndex, param: &Param) -> NodeIndex {
-        self.child(parent, param.to_string())
+        let node = self.child(parent, param.to_string());
+        for dimension in &param.dimensions {
+            self.add_array_dimension(node, dimension);
+        }
+        node
     }
 
     fn add_block_stmt(&mut self, parent: NodeIndex, block_stmt: &BlockStmt) -> NodeIndex {
@@ -153,6 +169,12 @@ impl AstGraphBuilder {
     fn add_expr(&mut self, parent: NodeIndex, expr: &Expr) -> NodeIndex {
         match &expr.value {
             ExprValue::IntLit(_) | ExprValue::Var(_) => self.child(parent, expr.value.to_string()),
+            ExprValue::ArrayAccess { array, index } => {
+                let node = self.child(parent, expr.value.to_string());
+                self.add_expr(node, array);
+                self.add_expr(node, index);
+                node
+            }
             ExprValue::BinaryOp { lhs, op: _, rhs } => {
                 let node = self.child(parent, expr.value.to_string());
                 self.add_expr(node, lhs);

src/ast/types.rs

@@ -17,7 +17,12 @@ pub struct VarDeclStmt {
 pub struct VarDeclStmtValue {
     pub name: String,
     pub name_span: Span,
+    pub dimensions: Vec<ArrayDimension>,
+}
 
+pub struct ArrayDimension {
+    pub value: Option<Expr>,
+    pub span: Span,
 }
 
 pub struct FuncDeclStmt {
@@ -89,6 +94,10 @@ pub struct Expr {
 pub enum ExprValue {
     IntLit(i64),
     Var(String),
+    ArrayAccess {
+        array: Box<Expr>,
+        index: Box<Expr>,
+    },
     BinaryOp {
         lhs: Box<Expr>, 
         op: BinaryOp, 
@@ -159,6 +168,7 @@ impl From<TypeIdent> for Type {
 pub struct Param {
     pub name: String,
     pub param_type: Type,
+    pub dimensions: Vec<ArrayDimension>,
     pub name_span: Span,
     pub type_span: Span,
 }
@@ -190,6 +200,12 @@ impl fmt::Display for VarDeclStmtValue {
     }
 }
 
+impl fmt::Display for ArrayDimension {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "ArrayDimension")
+    }
+}
+
 impl fmt::Display for FuncDeclStmt {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{} {}", self.return_type, self.name)
@@ -256,6 +272,7 @@ impl fmt::Display for ExprValue {
         match self {
             ExprValue::IntLit(value) => write!(f, "IntLit({})", value),
             ExprValue::Var(name) => write!(f, "Var({})", name),
+            ExprValue::ArrayAccess { .. } => write!(f, "ArrayAccess"),
             ExprValue::BinaryOp { op, .. } => write!(f, "BinaryOp({})", op),
             ExprValue::FuncCall(name, _) => write!(f, "FuncCall({})", name),
             ExprValue::Assign { .. } => write!(f, "Assign"),

src/backend/generator.rs

@@ -1,6 +1,6 @@
 use std::collections::BTreeMap;
 
-use crate::{backend::{arm_instr::{ARMInstr, AddInstr, BInstr, BlInstr, CmpInstr, ConditionCode, LoadInstr, LoadPseudoInstr, MoveInstr, MulInstr, PopInstr, PushInstr, RegisterOrImm, RsbInstr, SDivInstr, StoreInstr, SubInstr}, register_allocator::{REG_R0, REG_R1, REG_R2, REG_R3, Register, RegisterAlloc, RegisterAllocator}, types::ARMAsmVar}, ir::types::{Function, IRInstr, MoveRValue, Variable, VariableOrIntLit, VariableType}};
+use crate::{backend::{arm_instr::{ARMInstr, AddInstr, BInstr, BlInstr, CmpInstr, ConditionCode, LoadInstr, LoadPseudoInstr, MoveInstr, MulInstr, PopInstr, PushInstr, RegisterOrImm, RsbInstr, SDivInstr, StoreInstr, SubInstr}, register_allocator::{REG_FP, REG_R0, REG_R1, REG_R2, REG_R3, REG_SP, Register, RegisterAlloc, RegisterAllocator}, types::ARMAsmVar}, ir::types::{Function, IRInstr, MoveRValue, Variable, VariableOrIntLit, VariableType}};
 use crate::ir::types::BinaryOp as IRBinaryOp;
 use crate::ir::types::CmpOp as IRCmpOp;
 use crate::ir::types::UnaryOp as IRUnaryOp;
@@ -16,10 +16,82 @@ pub struct Generator {
 const DEFAULT_VAR_ALIGN: usize = 4;
 
 const ARG_REGS: [Register; 4] = [REG_R0, REG_R1, REG_R2, REG_R3];
+const ARM_DATA_IMM_CHUNK: i32 = 255;
+const ARM_LOAD_STORE_MAX_OFFSET: i32 = 4095;
+
+fn emit_sub_imm(dest: Register, left: Register, imm: i32, instrs: &mut Vec<ARMInstr>) {
+    if imm == 0 {
+        if dest != left {
+            instrs.push(MoveInstr::new_uncond(dest, RegisterOrImm::Reg(left)));
+        }
+        return;
+    }
+    let mut remaining = imm;
+    let first_chunk = remaining.min(ARM_DATA_IMM_CHUNK);
+    instrs.push(SubInstr::new(dest, left, RegisterOrImm::Imm(first_chunk)));
+    remaining -= first_chunk;
+    while remaining > 0 {
+        let chunk = remaining.min(ARM_DATA_IMM_CHUNK);
+        instrs.push(SubInstr::new(dest, dest, RegisterOrImm::Imm(chunk)));
+        remaining -= chunk;
+    }
+}
+
+fn emit_add_sp_imm(imm: i32, instrs: &mut Vec<ARMInstr>) {
+    let mut remaining = imm;
+    while remaining > 0 {
+        let chunk = remaining.min(ARM_DATA_IMM_CHUNK);
+        instrs.push(AddInstr::new_sp(chunk));
+        remaining -= chunk;
+    }
+}
+
+fn emit_sub_sp_imm(imm: i32, instrs: &mut Vec<ARMInstr>) {
+    let mut remaining = imm;
+    while remaining > 0 {
+        let chunk = remaining.min(ARM_DATA_IMM_CHUNK);
+        instrs.push(SubInstr::new_sp(chunk));
+        remaining -= chunk;
+    }
+}
+
+fn emit_load_stack(dest: Register, offset: i32, reg_allocator: &mut RegisterAllocator, instrs: &mut Vec<ARMInstr>) {
+    if offset <= ARM_LOAD_STORE_MAX_OFFSET {
+        instrs.push(LoadInstr::new_stack(dest, offset));
+    } else {
+        let addr_alloc = reg_allocator.alloc_any().expect("Ran out of registers");
+        emit_sub_imm(addr_alloc.reg, REG_FP, offset, instrs);
+        instrs.push(LoadInstr::new(dest, addr_alloc.reg, None));
+    }
+}
+
+fn emit_store_stack(src: Register, offset: i32, reg_allocator: &mut RegisterAllocator, instrs: &mut Vec<ARMInstr>) {
+    if offset <= ARM_LOAD_STORE_MAX_OFFSET {
+        instrs.push(StoreInstr::new_stack(src, offset));
+    } else {
+        let addr_alloc = reg_allocator.alloc_any().expect("Ran out of registers");
+        emit_sub_imm(addr_alloc.reg, REG_FP, offset, instrs);
+        instrs.push(StoreInstr::new(src, addr_alloc.reg, None));
+    }
+}
+
 fn load_variable(variable: Variable, reg_allocator: &mut RegisterAllocator, var_index_to_stack_offset: &BTreeMap<usize, usize>, instrs: &mut Vec<ARMInstr>) -> RegisterAlloc {
+    if variable.data_type.is_array() {
+        let var_alloc = reg_allocator.alloc(variable.clone()).expect("Ran out of registers");
+        match variable.var_type {
+            VariableType::Global => {
+                instrs.push(LoadPseudoInstr::new(var_alloc.reg, format!("global_var_{}", variable.index)));
+            }
+            _ => {
+                let stack_offset = var_index_to_stack_offset.get(&variable.index).expect("Variable not declared");
+                emit_sub_imm(var_alloc.reg, REG_FP, *stack_offset as i32, instrs);
+            }
+        }
+        return var_alloc;
+    }
     match variable.var_type {
         VariableType::Global => {
-            let var_alloc = reg_allocator.alloc(variable).expect("Ran out of registers");
+            let var_alloc = reg_allocator.alloc(variable.clone()).expect("Ran out of registers");
             let var_reg = var_alloc.reg;
             // if !var_alloc.is_reused {
                 let address_alloc = reg_allocator.alloc_any().expect("Ran out of registers");
@@ -34,14 +106,17 @@ fn load_variable(variable: Variable, reg_allocator: &mut RegisterAllocator, var_
                 let var_alloc = reg_allocator.alloc_reg(reg).expect("Ran out of registers");
                 var_alloc
             } else {
-                todo!("More than 4 parameters not supported yet");
+                let var_alloc = reg_allocator.alloc(variable.clone()).expect("Ran out of registers");
+                let stack_arg_offset = 8 + ((param_index - ARG_REGS.len()) * 4);
+                instrs.push(LoadInstr::new(var_alloc.reg, REG_FP, Some(RegisterOrImm::Imm(stack_arg_offset as i32))));
+                var_alloc
             }
         },
         _ => {
             let stack_offset = var_index_to_stack_offset.get(&variable.index).expect("Variable not declared");
-            let var_alloc = reg_allocator.alloc(variable).expect("Ran out of registers");
+            let var_alloc = reg_allocator.alloc(variable.clone()).expect("Ran out of registers");
             // if !var_alloc.is_reused {
-                instrs.push(LoadInstr::new_stack(var_alloc.reg, *stack_offset as i32));
+                emit_load_stack(var_alloc.reg, *stack_offset as i32, reg_allocator, instrs);
             // }
             var_alloc
         }
@@ -60,7 +135,7 @@ fn save_variable(variable: Variable, reg: Register, reg_allocator: &mut Register
         },
         _ => {
             let stack_offset = var_index_to_stack_offset.get(&variable.index).expect("Variable not declared");
-            instrs.push(StoreInstr::new_stack(reg, *stack_offset as i32));
+            emit_store_stack(reg, *stack_offset as i32, reg_allocator, instrs);
         }
     }
 }
@@ -134,6 +209,8 @@ impl Generator {
                 },
                 IRInstr::FuncCall(func, args, ret) => self.emit_func_call(func, args, ret, &var_index_to_stack_offset),
                 IRInstr::Move(dest, src) => self.emit_move(dest, src, &var_index_to_stack_offset),
+                IRInstr::Load(dest, addr) => self.emit_load(dest, addr, &var_index_to_stack_offset),
+                IRInstr::Store(addr, value) => self.emit_store(addr, value, &var_index_to_stack_offset),
                 IRInstr::Declare(variable) => {
                     assert!(!encounter_entry, "Variable declarations must come before entry instruction");
                     let size = variable.data_type.size_in_bytes();
@@ -143,7 +220,7 @@ impl Generator {
                 IRInstr::Entry => {
                     assert!(!encounter_entry, "Multiple entry instructions are not allowed");
                     encounter_entry = true;
-                    self.instrs.push(SubInstr::new_sp(stack_size_needed as i32));
+                    emit_sub_sp_imm(stack_size_needed as i32, &mut self.instrs);
                 },
                 IRInstr::DefineFunc(_, _, _) => unreachable!(),
                 IRInstr::Cmp(variable, left, cmp_op, right) => self.emit_cmp(variable, left, cmp_op, right, &var_index_to_stack_offset),
@@ -163,7 +240,7 @@ impl Generator {
     }
     fn emit_unary(&mut self, dest: Variable, unary_op: IRUnaryOp, variable: Variable, var_index_to_stack_offset: &BTreeMap<usize, usize>) {
         let variable_alloc = load_variable(variable, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
-        let dest_alloc = self.register_allocator.alloc(dest).expect("Ran out of registers");
+        let dest_alloc = self.register_allocator.alloc(dest.clone()).expect("Ran out of registers");
         match unary_op {
             IRUnaryOp::Neg => {
                 self.instrs.push(RsbInstr::new(dest_alloc.reg, variable_alloc.reg, RegisterOrImm::Imm(0)));
@@ -193,7 +270,7 @@ impl Generator {
                 alloc
             },
         };
-        let variable_alloc = self.register_allocator.alloc(variable).expect("Ran out of registers");
+        let variable_alloc = self.register_allocator.alloc(variable.clone()).expect("Ran out of registers");
         let variable_reg = variable_alloc.reg;
         self.instrs.push(CmpInstr::new(left_alloc.reg, RegisterOrImm::Reg(right_alloc.reg)));
         self.instrs.push(MoveInstr::new_uncond(variable_reg, RegisterOrImm::Imm(0)));
@@ -203,25 +280,38 @@ impl Generator {
     fn emit_func_call(&mut self, func: Function, args: Vec<Variable>, ret: Option<Variable>, var_index_to_stack_offset: &BTreeMap<usize, usize>) {
 
         self.instrs.push(PushInstr::new_push_caller_save());
-        if args.len() > 4 {
+        let stack_arg_count = args.len().saturating_sub(ARG_REGS.len());
-            todo!("More than 4 arguments not supported yet");
+        let stack_arg_size = stack_arg_count * 4;
+        let caller_save_size = 5 * 4;
+        let stack_padding = if (caller_save_size + stack_arg_size) % ARM_STACK_ALIGNMENT == 0 { 0 } else { 4 };
+        let extra_stack_size = stack_arg_size + stack_padding;
+        if extra_stack_size > 0 {
+            emit_sub_sp_imm(extra_stack_size as i32, &mut self.instrs);
         }
         let mut arg_reg_allocs = Vec::new();
         for (i, arg) in args.into_iter().enumerate() {
-            arg_reg_allocs.push(self.register_allocator.alloc_reg(ARG_REGS[i]).expect("Ran out of registers"));
             let arg_alloc = load_variable(arg, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
-            self.instrs.push(MoveInstr::new_uncond(ARG_REGS[i], RegisterOrImm::Reg(arg_alloc.reg)));
+            if i < ARG_REGS.len() {
+                arg_reg_allocs.push(self.register_allocator.alloc_reg(ARG_REGS[i]).expect("Ran out of registers"));
+                self.instrs.push(MoveInstr::new_uncond(ARG_REGS[i], RegisterOrImm::Reg(arg_alloc.reg)));
+            } else {
+                let stack_offset = ((i - ARG_REGS.len()) * 4) as i32;
+                self.instrs.push(StoreInstr::new(arg_alloc.reg, REG_SP, Some(RegisterOrImm::Imm(stack_offset))));
+            }
         }
         self.instrs.push(BlInstr::new(func.name.clone()));
         if let Some(ret) = ret {
             save_variable(ret, REG_R0, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
         }
 
+        if extra_stack_size > 0 {
+            emit_add_sp_imm(extra_stack_size as i32, &mut self.instrs);
+        }
 
         self.instrs.push(PopInstr::new_pop_caller_save());
     }
     fn emit_move(&mut self, dest: Variable, src: MoveRValue, var_index_to_stack_offset: &BTreeMap<usize, usize>) {
-        let dest_alloc = self.register_allocator.alloc(dest).expect("Ran out of registers");
+        let dest_alloc = self.register_allocator.alloc(dest.clone()).expect("Ran out of registers");
         let dest_register = dest_alloc.reg;
         match src {
             MoveRValue::Var(variable) => {
@@ -232,11 +322,25 @@ impl Generator {
         };
         save_variable(dest, dest_alloc.reg, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
     }
+
+    fn emit_load(&mut self, dest: Variable, addr: Variable, var_index_to_stack_offset: &BTreeMap<usize, usize>) {
+        let addr_alloc = load_variable(addr, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
+        let dest_alloc = self.register_allocator.alloc(dest.clone()).expect("Ran out of registers");
+        self.instrs.push(LoadInstr::new(dest_alloc.reg, addr_alloc.reg, None));
+        save_variable(dest, dest_alloc.reg, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
+    }
+
+    fn emit_store(&mut self, addr: Variable, value: Variable, var_index_to_stack_offset: &BTreeMap<usize, usize>) {
+        let addr_alloc = load_variable(addr, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
+        let value_alloc = load_variable(value, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
+        self.instrs.push(StoreInstr::new(value_alloc.reg, addr_alloc.reg, None));
+    }
+
     fn emit_binary(&mut self, dest: Variable, left: Variable, op: IRBinaryOp, right: Variable, var_index_to_stack_offset: &BTreeMap<usize, usize>) {
-        let dest_alloc = self.register_allocator.alloc(dest).expect("Ran out of registers");
+        let dest_alloc = self.register_allocator.alloc(dest.clone()).expect("Ran out of registers");
         let dest_reg = dest_alloc.reg;
         // should consider left == right
-        let left_alloc = load_variable(left, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
+        let left_alloc = load_variable(left.clone(), &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
         let (_right_alloc, right_reg) = if left != right {
             let right_alloc = load_variable(right, &mut self.register_allocator, var_index_to_stack_offset, &mut self.instrs);
             let right_reg = right_alloc.reg;

src/backend/mod.rs

@@ -15,6 +15,7 @@ mod tests {
     use crate::utils::case_list::CaseList;
     use crate::utils::num_sequence::NumberSequence;
     use crate::ir::generator::Generator as IRGenerator;
+    use crate::sema::analyzer::Analyzer;
     pub use super::generator::Generator as ASMGenerator;
     fn test_case(case_str: &str) {
         let case_sequence = NumberSequence::from_str(case_str).unwrap();
@@ -49,12 +50,14 @@ mod tests {
                 parser.diagnostics.print(&format!("{}", case_path.display()), &full_text);
                 is_error = true;
             }
-            let mut generator = IRGenerator::new();
+            let mut analyzer = Analyzer::new();
-            let ir = generator.emit(compile_unit);
+            let hir = analyzer.analyze(compile_unit);
-            // if !generator.diagnostic.is_empty() {
+            if !analyzer.get_diagnostics().is_empty() {
-            //     generator.diagnostic.print(&format!("{}", case_path.display()), &full_text);
+                analyzer.get_diagnostics().print(&format!("{}", case_path.display()), &full_text);
-            //     is_error = true;
+                is_error = true;
-            // }
+            }
+            let mut generator = IRGenerator::new(&analyzer);
+            let ir = generator.emit(hir);
             let mut asm_generator = ASMGenerator::new();
             asm_generator.emit(ir);
             let asm_text = asm_generator.to_text();

src/backend/register_allocator.rs

@@ -84,7 +84,7 @@ impl RegisterAllocatorInner {
                     *use_kind = RegisterUseKind::Free;
                 },
                 RegisterUseKind::UsedByVariable(var) => {
-                    *use_kind = RegisterUseKind::AllocatedToVariable(*var);
+                    *use_kind = RegisterUseKind::AllocatedToVariable(var.clone());
                 },
                 _ => panic!("Trying to mark a register as unused that is not in use"),
             }
@@ -139,8 +139,8 @@ impl RegisterAllocator {
                 continue;
             }
             if let RegisterUseKind::Free = use_kind {
-                *use_kind = RegisterUseKind::UsedByVariable(var);
+                *use_kind = RegisterUseKind::UsedByVariable(var.clone());
-                inner.variable_to_register.insert(var, reg);
+                inner.variable_to_register.insert(var.clone(), reg);
                 return Some(RegisterAlloc {
                     allocator: Rc::downgrade(&self.inner),
                     reg,
@@ -156,8 +156,8 @@ impl RegisterAllocator {
             }
             if let RegisterUseKind::AllocatedToVariable(ori_var) = use_kind {
                 assert!(variable_to_register.remove(&ori_var).is_some());
-                *use_kind = RegisterUseKind::UsedByVariable(var);
+                *use_kind = RegisterUseKind::UsedByVariable(var.clone());
-                variable_to_register.insert(var, reg);
+                variable_to_register.insert(var.clone(), reg);
                 return Some(RegisterAlloc {
                     allocator: Rc::downgrade(&self.inner),
                     reg,

src/err.rs

@@ -1,9 +1,11 @@
 use thiserror::Error;
 
-use crate::frontend::err::FrontendError;
+use crate::{frontend::err::FrontendError, sema::err::SemaError};
 
 #[derive(Debug, Clone, PartialEq, Eq, Error)]
 pub enum CompileError {
     #[error(transparent)]
     Frontend(#[from] FrontendError),
+    #[error(transparent)]
+    Sema(#[from] SemaError),
 }

src/frontend/lexer.rs

@@ -17,7 +17,7 @@ pub struct Lexer {
 
 const WHITESPACE_CHARS: &[char] = &[' ', '\t', '\n', '\r'];
 const DELIMITER_CHARS: &[char] = &[
-    '+', '-', '*', '/', '%', '=', '!', '<', '>', '(', ')', ',', ';', '{', '|', '&'
+    '+', '-', '*', '/', '%', '=', '!', '<', '>', '(', ')', '[', ']', ',', ';', '{', '|', '&'
 ];
 struct Cursor {
     chars: Vec<char>,
@@ -248,6 +248,8 @@ fn parse_delimiter(
         ')' => TokenValue::RParen,
         '{' => TokenValue::LBrace,
         '}' => TokenValue::RBrace,
+        '[' => TokenValue::LBracket,
+        ']' => TokenValue::RBracket,
         _ => return Err(LexParseError::NotMatched),
     };
     str_iter.advance(1);

src/frontend/parser.rs

@@ -1,6 +1,6 @@
 use crate::{
     ast::types::{
-        BinaryOp, BlockStmt, BreakStmt, CompileUnit, ContinueStmt, Expr, ExprValue, FuncDeclStmt, GlobalDeclStmt, IfElseBranch, IfStmt, Param, ReturnStmt, Statement, UnaryOp, VarDeclStmt, VarDeclStmtValue, WhileStmt
+        ArrayDimension, BinaryOp, BlockStmt, BreakStmt, CompileUnit, ContinueStmt, Expr, ExprValue, FuncDeclStmt, GlobalDeclStmt, IfElseBranch, IfStmt, Param, ReturnStmt, Statement, UnaryOp, VarDeclStmt, VarDeclStmtValue, WhileStmt
     },
     diagnostic::{Diagnositics, span::Span},
     frontend::{
@@ -259,6 +259,7 @@ impl Parser {
         Ok(Param {
             param_type: param_type.into(),
             name,
+            dimensions: self.parse_array_dimensions(true)?,
             name_span,
             type_span,
         })
@@ -300,7 +301,8 @@ impl Parser {
                 }
             }
         };
-        values.push(VarDeclStmtValue { name, name_span });
+        let dimensions = self.parse_array_dimensions(false)?;
+        values.push(VarDeclStmtValue { name, name_span, dimensions });
         let mut last_name = true; // indicate whether the last parsed token is a variable name
         while let Some(t) = self.peek() {
             if matches!(t.value, TokenValue::Semicolon) { // statement end
@@ -319,7 +321,8 @@ impl Parser {
             }
             if let Some(ident) = self.peek().unwrap().value.as_ident() {
                 let span = self.next().unwrap().span;
-                values.push(VarDeclStmtValue { name: ident, name_span: span });
+                let dimensions = self.parse_array_dimensions(false)?;
+                values.push(VarDeclStmtValue { name: ident, name_span: span, dimensions });
                 last_name = true;
             } else {
                 let token = self.next().unwrap().clone();
@@ -334,6 +337,50 @@ impl Parser {
         Ok(VarDeclStmt { values, type_span, data_type: var_type.into()  })
     }
 
+    fn parse_array_dimensions(&mut self, allow_empty_first: bool) -> Result<Vec<ArrayDimension>, ParseProcessError> {
+        let mut dimensions = vec![];
+        while self.peek().is_some_and(|t| t.value == TokenValue::LBracket) {
+            let start_span = self.next().unwrap().span;
+            let value = if self.peek().is_some_and(|t| t.value == TokenValue::RBracket) {
+                if !allow_empty_first || !dimensions.is_empty() {
+                    let span = self.peek().unwrap().span;
+                    self.diagnostics.add_from_frontend_error(
+                        ParseError::UnexpectedToken(TokenValue::RBracket, "array dimension expression"),
+                        span,
+                    );
+                    return Err(ParseProcessError::ErrorInMatch);
+                }
+                None
+            } else {
+                Some(self.parse_expr()?)
+            };
+            let end_span = match self.peek() {
+                Some(t) if t.value == TokenValue::RBracket => {
+                    let span = t.span;
+                    self.advance(1);
+                    span
+                }
+                Some(_) => {
+                    let token = self.next().unwrap().clone();
+                    self.diagnostics.add_from_frontend_error(
+                        ParseError::UnexpectedToken(token.value, "`]`"),
+                        token.span,
+                    );
+                    return Err(ParseProcessError::ErrorInMatch);
+                }
+                None => {
+                    self.diagnostics.add_from_frontend_error(ParseError::ExpectButEof("`]`"), start_span);
+                    return Err(ParseProcessError::ErrorInMatch);
+                }
+            };
+            dimensions.push(ArrayDimension {
+                value,
+                span: Span::from_two(start_span, end_span),
+            });
+        }
+        Ok(dimensions)
+    }
+
     fn parse_block_stmt(&mut self, parse_type: ParseType) -> Result<BlockStmt, ParseProcessError> {
         assert!(self.peek().is_some());
         if self
@@ -598,7 +645,7 @@ impl Parser {
     //        }
     //    }
     // }
-    fn parse_primary(&mut self) -> Result<Expr, ParseProcessError> {
+    fn parse_primary_atom(&mut self) -> Result<Expr, ParseProcessError> {
         assert!(self.peek().is_some());
         let token = self.next().unwrap().clone();
         match token.value {
@@ -712,6 +759,47 @@ impl Parser {
             }
         }
     }
+    fn parse_primary(&mut self) -> Result<Expr, ParseProcessError> {
+        let mut expr = self.parse_primary_atom()?;
+        while self.peek().is_some_and(|t| t.value == TokenValue::LBracket) {
+            let start_span = expr.span;
+            self.advance(1);
+            let index = match self.peek() {
+                Some(_) => self.parse_expr()?,
+                None => {
+                    self.diagnostics.add_from_frontend_error(ParseError::ExpectButEof("array index expression"), start_span);
+                    return Err(ParseProcessError::ErrorInMatch);
+                }
+            };
+            let end_span = match self.peek() {
+                Some(t) if t.value == TokenValue::RBracket => {
+                    let span = t.span;
+                    self.advance(1);
+                    span
+                }
+                Some(_) => {
+                    let token = self.next().unwrap().clone();
+                    self.diagnostics.add_from_frontend_error(
+                        ParseError::UnexpectedToken(token.value, "`]`"),
+                        token.span,
+                    );
+                    return Err(ParseProcessError::ErrorInMatch);
+                }
+                None => {
+                    self.diagnostics.add_from_frontend_error(ParseError::ExpectButEof("`]`"), index.span);
+                    return Err(ParseProcessError::ErrorInMatch);
+                }
+            };
+            expr = Expr {
+                value: ExprValue::ArrayAccess {
+                    array: Box::new(expr),
+                    index: Box::new(index),
+                },
+                span: Span::from_two(start_span, end_span),
+            };
+        }
+        Ok(expr)
+    }
     fn parse_unary(&mut self) -> Result<Expr, ParseProcessError> {
         assert!(self.peek().is_some());
         let token = self.peek().unwrap().clone();
@@ -937,40 +1025,21 @@ impl Parser {
     }
     fn parse_assign(&mut self) -> Result<Expr, ParseProcessError> {
         assert!(self.peek().is_some());
-        let is_assign = matches!(
+        let lvalue = self.parse_logical_or()?;
-            (self.tokens.get(self.pos), self.tokens.get(self.pos + 1)),
+        if !self.peek().is_some_and(|t| t.value == TokenValue::Equal) {
-            (
+            return Ok(lvalue);
-                Some(Token {
-                    value: TokenValue::Ident(_),
-                    ..
-                }),
-                Some(Token {
-                    value: TokenValue::Equal,
-                    ..
-                })
-            )
-        );
-        if !is_assign {
-            return self.parse_logical_or();
         }
-
-        let lvalue_token = self.next().unwrap().clone();
-        let name = lvalue_token.value.as_ident().unwrap();
         self.advance(1);
         let rvalue = match self.peek() {
             Some(_) => self.parse_assign()?,
             None => {
                 self.diagnostics.add_from_frontend_error(
                     ParseError::ExpectButEof("expression"),
-                    lvalue_token.span,
+                    lvalue.span,
                 );
                 return Err(ParseProcessError::ErrorInMatch);
             }
         };
-        let lvalue = Expr {
-            value: ExprValue::Var(name),
-            span: lvalue_token.span,
-        };
         let span = Span::from_two(lvalue.span, rvalue.span);
         Ok(Expr {
             value: ExprValue::Assign {
@@ -1100,4 +1169,8 @@ mod tests {
     fn test_func() {
         test_case("12-13,58-60");
     }
+    #[test]
+    fn test_array() {
+        test_case("4-7,11,42,71,74-78,82,84,86,90,95,96,100,101,103");
+    }
 }

src/frontend/types.rs

@@ -21,6 +21,7 @@ pub enum TokenValue {
 
     LParen, RParen,
     LBrace, RBrace,
+    LBracket, RBracket,
     Comma, Semicolon,
 
     If, Else, While, Return, Break, Continue,
@@ -69,6 +70,8 @@ impl std::fmt::Display for TokenValue {
             TokenValue::RParen => write!(f, "`)`"),
             TokenValue::LBrace => write!(f, "`{{`"),
             TokenValue::RBrace => write!(f, "`}}`"),
+            TokenValue::LBracket => write!(f, "`[`"),
+            TokenValue::RBracket => write!(f, "`]`"),
             TokenValue::Comma => write!(f, "`,`"),
             TokenValue::Semicolon => write!(f, "`;`"),
             TokenValue::If => write!(f, "if"),
@@ -94,6 +97,7 @@ pub enum TokenKind {
 
     LParen, RParen,
     LBrace, RBrace,
+    LBracket, RBracket,
     Comma, Semicolon,
 
     If, Else, While, Return, Break, Continue,

src/ir/generator.rs

@@ -1,13 +1,11 @@
-use std::{collections::{BTreeMap, BTreeSet}, vec};
+use std::{collections::BTreeMap, vec};
 
-use crate::{ast::types::{BlockStmt, BreakStmt, CompileUnit, ContinueStmt, Expr, ExprValue, FuncDeclStmt, GlobalDeclStmt, IfElseBranch, IfStmt, ReturnStmt, Statement, VarDeclStmt, WhileStmt}, diagnostic::Diagnositics, ir::{err::IRError, types::{BinaryOp, CmpOp, Function, IRInstr, IRType, MoveRValue, UnaryOp, Variable, VariableOrIntLit, VariableType}}};
+use crate::{ir::types::{CmpOp, Function, IRInstr, IRType, MoveRValue, UnaryOp, Variable, VariableOrIntLit, VariableType}, sema::{analyzer::Analyzer as SemaAnalyzer, hir::{HirBlockStmt, HirBreakStmt, HirCompileUnit, HirContinueStmt, HirExpr, HirExprValue, HirFuncDeclStmt, HirGlobalDeclStmt, HirIfElseBranch, HirIfStmt, HirReturnStmt, HirStatement, HirVarDeclStmt, HirWhileStmt}, symbol::{FunctionId, SymbolId}}};
 use crate::ast::types::BinaryOp as AstBinaryOp;
 use crate::ast::types::UnaryOp as AstUnaryOp;
-pub struct Generator {
+pub struct Generator<'a> {
+    sema: &'a SemaAnalyzer,
     var_manager: VariableManager,
-    function_map: BTreeMap<String, Function>,
-    current_func_return_type: Option<IRType>,
-    diagnostic: Diagnositics,
     current_exit_label: Vec<Option<(usize, usize)>>, // true exit, false exit
     // About exit label passing:
     // for non-logical parent expr, current_exit_label is None
@@ -19,24 +17,11 @@ pub struct Generator {
     label_counter: usize
 }
 
-impl Generator {
+impl<'a> Generator<'a> {
-    pub fn new() -> Self {
+    pub fn new(sema: &'a SemaAnalyzer) -> Self {
-        let mut function_map = BTreeMap::new();
-        function_map.insert("putint".to_string(), Function {
-            name: "putint".to_string(),
-            parameter_types: vec![IRType::I32],
-            return_type: IRType::Void,
-        });
-        function_map.insert("getint".to_string(), Function {
-            name: "getint".to_string(),
-            parameter_types: vec![],
-            return_type: IRType::I32,
-        });
         Self {
+            sema,
             var_manager: VariableManager::new(),
-            current_func_return_type: None,
-            diagnostic: Diagnositics::new(),
-            function_map,
             current_exit_label: vec![],
             while_exit_label: vec![],
             func_exit: None,
@@ -48,15 +33,22 @@ impl Generator {
         self.label_counter += 1;
         label
     }
-    pub fn emit(&mut self, compile_unit: CompileUnit) -> Vec<IRInstr> {
+    pub fn emit(&mut self, compile_unit: HirCompileUnit) -> Vec<IRInstr> {
         self.generate_compile_unit(compile_unit)
     }
-    pub fn get_diagnostics(&self) -> &Diagnositics {
+
-        &self.diagnostic
+    fn ir_function(&self, function_id: FunctionId) -> Function {
+        let sig = self.sema.get_function_sig(function_id);
+        Function {
+            name: sig.name.clone(),
+            parameter_types: sig.parameter_types.iter().map(|ty| ty.clone().into()).collect(),
+            return_type: sig.return_type.clone().into(),
+        }
     }
-    fn generate_compile_unit(&mut self, compile_unit: CompileUnit) -> Vec<IRInstr> {
+
+    fn generate_compile_unit(&mut self, compile_unit: HirCompileUnit) -> Vec<IRInstr> {
         let mut instrs = vec![];
-        use GlobalDeclStmt::*;
+        use HirGlobalDeclStmt::*;
         for decl in compile_unit.global_decls {
             match decl {
                 VarDecl(var_decl) => {
@@ -70,48 +62,29 @@ impl Generator {
         instrs
     }
 
-    fn generate_var_decl(&mut self, var_decl: VarDeclStmt, is_global: bool) -> Vec<IRInstr> {
+    fn generate_var_decl(&mut self, var_decl: HirVarDeclStmt, is_global: bool) -> Vec<IRInstr> {
         let mut instrs = vec![];
         let var_type = if is_global { VariableType::Global } else { VariableType::Local };
         for value in var_decl.values {
-            match self.var_manager.declare_variable(&value.name, var_type, var_decl.data_type.into()) {
+            let var = self.var_manager.declare_symbol(value.symbol, var_type, self.sema.get_symbol_type(value.symbol).into());
-                Ok(var) => {
+            if is_global {
-                    if is_global { instrs.push(IRInstr::Declare(var)); }
+                instrs.push(IRInstr::Declare(var));
-                }
-                Err(e) => {
-                    self.diagnostic.add_from_ir_error(e, value.name_span);
-                }
             }
         }
 
         instrs
     }
 
-    fn generate_func_decl(&mut self, func_decl: FuncDeclStmt) -> Vec<IRInstr> {
+    fn generate_func_decl(&mut self, func_decl: HirFuncDeclStmt) -> Vec<IRInstr> {
-        if self.function_map.contains_key(&func_decl.name) {
+        let parameters: Vec<Variable> = func_decl.params.iter()
-            self.diagnostic.add_from_ir_error(IRError::FunctionHasBeenDefined(func_decl.name.clone()), func_decl.name_span);
+            .map(|param| self.var_manager.declare_symbol(param.symbol, VariableType::Local, param.param_type.clone().into()))
-            return vec![];
+            .collect();
-        }
-        self.current_func_return_type = Some(func_decl.return_type.into());
-        self.var_manager.enter_scope();
-        let parameters: Vec<Variable> =  match func_decl.params.iter().map(|param| {
-            match self.var_manager.declare_variable(&param.name, VariableType::Local, param.param_type.into()) {
-                Ok(var) => Ok(var),
-                Err(e) => {
-                    self.diagnostic.add_from_ir_error(e, param.name_span);
-                    Err(())
-                }
-            }
-        }).collect() {
-            Ok(p) => p,
-            Err(()) => return vec![],
-        };
         let temp_parameters = parameters.iter().enumerate()
-            .map(|(i, param)| self.var_manager.declare_param_temp(param.data_type, i))
+            .map(|(i, param)| self.var_manager.declare_param_temp(param.data_type.clone(), i))
             .collect::<Vec<_>>();
         let mut body_instrs = vec![];
         self.func_exit = Some((self.request_label(),  {
-            let ret_type = func_decl.return_type.into();
+            let ret_type = func_decl.sig.return_type.into();
             if ret_type != IRType::Void {
                 Some(self.var_manager.declare_unamed_local(ret_type))
             } else {
@@ -127,24 +100,18 @@ impl Generator {
         }
         body_instrs.push(IRInstr::Entry);
         parameters.iter().zip(temp_parameters.iter()).for_each(|(param, temp_param)| {
-            body_instrs.push(IRInstr::Move(*param, MoveRValue::Var(*temp_param)));
+            body_instrs.push(IRInstr::Move(param.clone(), MoveRValue::Var(temp_param.clone())));
         });
         body_instrs.extend(block_instrs);
         let func_exit = self.func_exit.take().unwrap();
         body_instrs.push(IRInstr::Label(func_exit.0));
         body_instrs.push(IRInstr::Exit(func_exit.1));
-        self.var_manager.exit_scope();
-        self.current_func_return_type = None;
         self.var_manager.clear_local_counter();
-        let func  = Function {
+        let mut func = self.ir_function(func_decl.sig.id);
-            name: func_decl.name,
+        func.parameter_types = temp_parameters.iter().map(|v| v.data_type.clone()).collect();
-            parameter_types: temp_parameters.iter().map(|v| v.data_type).collect(),
-            return_type: func_decl.return_type.into(),
-        };
-        self.function_map.insert(func.name.clone(), func.clone());
         vec![IRInstr::DefineFunc(func, temp_parameters, body_instrs)]
     }
-    fn generate_block_stmt(&mut self, block_stmt: BlockStmt) -> Vec<IRInstr> {
+    fn generate_block_stmt(&mut self, block_stmt: HirBlockStmt) -> Vec<IRInstr> {
         let mut instrs = vec![];
         for stmt in block_stmt.statements {
             instrs.extend(self.generate_statement(stmt));
@@ -152,8 +119,8 @@ impl Generator {
         instrs
     }
 
-    fn generate_statement(&mut self, stmt: Statement) -> Vec<IRInstr> {
+    fn generate_statement(&mut self, stmt: HirStatement) -> Vec<IRInstr> {
-        use Statement::*;
+        use HirStatement::*;
         let instrs = match stmt {
             Return(return_stmt) => self.generate_return_stmt(return_stmt),
             If(if_stmt) => self.generate_if_stmt(if_stmt),
@@ -161,10 +128,7 @@ impl Generator {
             Break(break_stmt) => self.generate_break_stmt(break_stmt),
             Continue(continue_stmt) => self.generate_continue_stmt(continue_stmt),
             Block(block_stmt) => {
-                self.var_manager.enter_scope();
+                self.generate_block_stmt(block_stmt)
-                let block_instrs = self.generate_block_stmt(block_stmt);
-                self.var_manager.exit_scope();
-                block_instrs
             },
             Expr(expr) => {
                 self.current_exit_label.push(None);
@@ -183,16 +147,11 @@ impl Generator {
         instrs
     }
 
-    fn generate_return_stmt(&mut self, return_stmt: ReturnStmt) -> Vec<IRInstr> {
+    fn generate_return_stmt(&mut self, return_stmt: HirReturnStmt) -> Vec<IRInstr> {
         let mut instrs = vec![];
-        let func_exit = self.func_exit.unwrap();
+        let func_exit = self.func_exit.clone().unwrap();
         match return_stmt.value {
             Some(expr) => {
-                if func_exit.1.is_none() {
-                    // shouldn't return value but return stmt has expr;
-                    self.diagnostic.add_from_ir_error(IRError::ReturnExpressionOnVoidFunction, return_stmt.span);
-                    return vec![];
-                }
                 self.current_exit_label.push(None);
                 let (value_instrs, value_var) = match self.generate_expr(expr) {
                     Some(res) => res,
@@ -202,37 +161,21 @@ impl Generator {
                     }
                 };
                 self.current_exit_label.pop();
-                if value_var.is_none() {
-                    self.diagnostic.add_from_ir_error(IRError::InvalidOperand(IRType::Void), return_stmt.span);
-                    self.current_exit_label.pop();
-                    return vec![];
-                }
                 instrs.extend(value_instrs);
                 instrs.push(IRInstr::Move(func_exit.1.unwrap(), MoveRValue::Var(value_var.unwrap())));
-                // if value_var.is_none() {
-                //     self.diagnostic.add_from_ir_error(IRError::InvalidOperand(IRType::Void), return_stmt.span);
-                //     return vec![];
-                // }
-                // let value_var = value_var.unwrap();
             }
-            None => {
+            None => {},
-                if func_exit.1.is_some() {
-                    // should return value but return stmt has no expr;
-                    self.diagnostic.add_from_ir_error(IRError::TypeMismatch(self.current_func_return_type.unwrap(), IRType::Void), return_stmt.span);
-                }
-            },
         }
         instrs.push(IRInstr::Goto(func_exit.0));
         instrs
     }
-    fn generate_while_stmt(&mut self, while_stmt: WhileStmt) -> Vec<IRInstr> {
+    fn generate_while_stmt(&mut self, while_stmt: HirWhileStmt) -> Vec<IRInstr> {
         let mut instrs = vec![];
         let cond_label = self.request_label();
         let body_label = self.request_label();
         let exit_label = self.request_label();
         instrs.push(IRInstr::Label(cond_label));
         self.current_exit_label.push(Some((body_label, exit_label)));
-        let while_cond_span = while_stmt.condition.span;
         let (cond_instrs, cond_var) = match self.generate_expr(while_stmt.condition) {
             Some(res) => res,
             None => {
@@ -241,10 +184,6 @@ impl Generator {
             }
         };
         self.current_exit_label.pop();
-        if cond_var.is_none() {
-            self.diagnostic.add_from_ir_error(IRError::InvalidOperand(IRType::Void), while_cond_span);
-            return vec![];
-        }
         instrs.extend(cond_instrs);
         instrs.push(IRInstr::Label(body_label));
         self.while_exit_label.push((cond_label, exit_label));
@@ -254,7 +193,7 @@ impl Generator {
         instrs.push(IRInstr::Label(exit_label));
         instrs
     }
-    fn generate_if_stmt(&mut self, if_stmt: IfStmt) -> Vec<IRInstr> {
+    fn generate_if_stmt(&mut self, if_stmt: HirIfStmt) -> Vec<IRInstr> {
         let mut instrs = vec![];
         let then_label = self.request_label();
         let exit_label = self.request_label();
@@ -273,7 +212,6 @@ impl Generator {
         labels.push(exit_label);
         // now generate if expr, true exit to labels[0], false exit to labels[1]
         self.current_exit_label.push(Some((labels[0], labels[1])));
-        let cond_span = if_stmt.condition.span;
         let (cond_instrs, cond_var) = match self.generate_expr(if_stmt.condition) {
             Some(res) => res,
             None => {
@@ -282,19 +220,14 @@ impl Generator {
             }
         };
         self.current_exit_label.pop();
-        if cond_var.is_none() {
-            self.diagnostic.add_from_ir_error(IRError::InvalidOperand(IRType::Void), cond_span);
-            return vec![];
-        }
         instrs.extend(cond_instrs);
         instrs.push(IRInstr::Label(labels[0]));
         instrs.extend(self.generate_block_stmt(if_stmt.then_branch));
         instrs.push(IRInstr::Goto(exit_label));
         for (i, else_if_branch) in if_stmt.ifelse_branch.into_iter().enumerate() {
-            let IfElseBranch { condition: else_if_cond, then_branch: else_if_block } = else_if_branch;
+            let HirIfElseBranch { condition: else_if_cond, then_branch: else_if_block } = else_if_branch;
             instrs.push(IRInstr::Label(labels[i * 2 + 1]));
             self.current_exit_label.push(Some((labels[i * 2 + 2], labels[i * 2 + 3])));
-            let else_if_cond_span = else_if_cond.span;
             let (else_if_cond_instrs, else_if_cond_var) = match self.generate_expr(else_if_cond) {
                 Some(res) => res,
                 None => {
@@ -303,10 +236,6 @@ impl Generator {
                 }
             };
             self.current_exit_label.pop();
-            if else_if_cond_var.is_none() {
-                self.diagnostic.add_from_ir_error(IRError::InvalidOperand(IRType::Void), else_if_cond_span);
-                return vec![];
-            }
             instrs.extend(else_if_cond_instrs);
             instrs.push(IRInstr::Label(labels[i * 2 + 2]));
             instrs.extend(self.generate_block_stmt(else_if_block));
@@ -320,71 +249,70 @@ impl Generator {
         instrs.push(IRInstr::Label(exit_label));
         instrs
     }
-    fn generate_continue_stmt(&mut self, stmt: ContinueStmt) -> Vec<IRInstr> {
+    fn generate_continue_stmt(&mut self, _stmt: HirContinueStmt) -> Vec<IRInstr> {
         if let Some((continue_label, _)) = self.while_exit_label.last() {
             vec![IRInstr::Goto(*continue_label)]
         } else {
-            self.diagnostic.add_from_ir_error(IRError::ContinueOutsideLoop, stmt.span);
             vec![]
         }
     }
-    fn generate_break_stmt(&mut self, stmt: BreakStmt) -> Vec<IRInstr> {
+    fn generate_break_stmt(&mut self, _stmt: HirBreakStmt) -> Vec<IRInstr> {
         if let Some((_, break_label)) = self.while_exit_label.last() {
             vec![IRInstr::Goto(*break_label)]
         } else {
-            self.diagnostic.add_from_ir_error(IRError::BreakOutsideLoop, stmt.span);
             vec![]
         }
     }
-    fn generate_expr(&mut self, expr: Expr) -> Option<(Vec<IRInstr>, Option<Variable>)> {
+    fn generate_expr(&mut self, expr: HirExpr) -> Option<(Vec<IRInstr>, Option<Variable>)> {
         // there may be some expr that doesn't produce value, like void func call
         let (mut instrs, var) = match expr.value {
-            ExprValue::IntLit(i) => {
+            HirExprValue::IntLit(i) => {
                 // TODO: convert check
                 let var = self.var_manager.declare_temp(IRType::I32);
-                (vec![IRInstr::Move(var, MoveRValue::ConstInt(i as i32))], Some(var))
+                (vec![IRInstr::Move(var.clone(), MoveRValue::ConstInt(i as i32))], Some(var))
             },
-            ExprValue::Var(name) => {
+            HirExprValue::Var(symbol) => {
-                if let Some(var) = self.var_manager.get_variable(&name) {
+                let var = self.var_manager.get_symbol(symbol).unwrap();
+                if var.data_type.is_array() {
+                    let ptr_ty = var.data_type.decay_to_ptr().unwrap();
+                    let dest = self.var_manager.declare_temp(ptr_ty);
+                    (vec![IRInstr::Move(dest.clone(), MoveRValue::Var(var))], Some(dest))
+                } else {
                     (vec![], Some(var))
-                } else {
-                    self.diagnostic.add_from_ir_error(IRError::VariableNotFound(name.clone()), expr.span);
-                    return None;
                 }
             },
-            ExprValue::Assign { lvalue, rvalue } => {
+            HirExprValue::Assign { lvalue, rvalue } => {
-                // TODO: only support simple variable assignment now, need to support more complex lvalue in the future
+                let lvalue_ty: IRType = lvalue.ty.clone().into();
-                if let ExprValue::Var(name) = lvalue.value {
+                self.current_exit_label.push(None);
-                    let var = match self.var_manager.get_variable(&name) {
+                let (mut instrs, rvalue_var) = self.generate_expr(*rvalue)?;
-                        Some(var) => var,
+                self.current_exit_label.pop();
-                        None => {
+                let (lvalue_instrs, target, is_addr) = self.generate_lvalue(*lvalue)?;
-                            self.diagnostic.add_from_ir_error(IRError::VariableNotFound(name.clone()), lvalue.span);
+                instrs.extend(lvalue_instrs);
-                            return None;
+                if is_addr {
-                        }
+                    instrs.push(IRInstr::Store(target.clone(), rvalue_var.unwrap()));
-                    };
-                    self.current_exit_label.push(None);
-                    let rvalue_span = rvalue.span;
-                    let (mut instrs, rvalue_var) = self.generate_expr(*rvalue)?;
-                    self.current_exit_label.pop();
-                    // TODO: further check
-                    // if var.data_type != rvalue_var.data_type {
-                    //     self.diagnostic.add_from_ir_error(IRError::TypeMismatch(var.data_type, rvalue_var.data_type), lvalue.span);
-                    //     return (vec![], None);
-                    // }
-                    if rvalue_var.is_none() {
-                        self.diagnostic.add_from_ir_error(IRError::InvalidOperand(IRType::Void), rvalue_span);
-                        return None;
-                    }
-                    instrs.push(IRInstr::Move(var, MoveRValue::Var(rvalue_var.unwrap())));
-                    let temp_var = self.var_manager.declare_temp(var.data_type);
-                    instrs.push(IRInstr::Move(temp_var, MoveRValue::Var(var)));
-                    (instrs, Some(temp_var))
                 } else {
-                    self.diagnostic.add_from_ir_error(IRError::InvalidAssignmentTarget, lvalue.span);
+                    instrs.push(IRInstr::Move(target.clone(), MoveRValue::Var(rvalue_var.unwrap())));
-                    return None;
+                }
+                let temp_var = self.var_manager.declare_temp(lvalue_ty);
+                if is_addr {
+                    instrs.push(IRInstr::Load(temp_var.clone(), target));
+                } else {
+                    instrs.push(IRInstr::Move(temp_var.clone(), MoveRValue::Var(target)));
+                }
+                (instrs, Some(temp_var))
+            },
+            HirExprValue::ArrayAccess { array, index } => {
+                let result_ty: IRType = expr.ty.clone().into();
+                let (mut instrs, addr) = self.generate_array_element_addr(*array, *index)?;
+                if result_ty.is_array() {
+                    (instrs, Some(addr))
+                } else {
+                    let dest = self.var_manager.declare_temp(result_ty);
+                    instrs.push(IRInstr::Load(dest.clone(), addr));
+                    (instrs, Some(dest))
                 }
             },
-            ExprValue::UnaryOp { op, operand } => {
+            HirExprValue::UnaryOp { op, operand } => {
                 let mut parent_is_logical = true;
                 let exit_passdown = if matches!(op, AstUnaryOp::Not) {
                     Some(self.current_exit_label.last().cloned().flatten().map_or_else(|| {
@@ -409,36 +337,31 @@ impl Generator {
 
 
                 self.current_exit_label.push(exit_passdown);
-                let operand_span = operand.span;
                 let (mut instrs, operand_var) = self.generate_expr(*operand)?;
                 self.current_exit_label.pop();
-                if operand_var.is_none() {
-                    self.diagnostic.add_from_ir_error(IRError::InvalidOperand(IRType::Void), operand_span);
-                    return None;
-                }
                 let operand_var = operand_var.unwrap();
                 let dest_var = match op {
                     AstUnaryOp::Add => {
-                        let dest_var = self.var_manager.declare_temp(operand_var.data_type);
+                        let dest_var = self.var_manager.declare_temp(operand_var.data_type.clone());
-                        instrs.push(IRInstr::Move(dest_var, MoveRValue::Var(operand_var)));
+                        instrs.push(IRInstr::Move(dest_var.clone(), MoveRValue::Var(operand_var)));
                         dest_var
                     },
                     AstUnaryOp::Sub => {
-                        let dest_var = self.var_manager.declare_temp(operand_var.data_type);
+                        let dest_var = self.var_manager.declare_temp(operand_var.data_type.clone());
-                        instrs.push(IRInstr::Unary(dest_var, UnaryOp::Neg, operand_var));
+                        instrs.push(IRInstr::Unary(dest_var.clone(), UnaryOp::Neg, operand_var));
                         dest_var
                     },
                     AstUnaryOp::Not => {
-                        let dest_var = self.var_manager.declare_unamed_local(operand_var.data_type);
+                        let dest_var = self.var_manager.declare_unamed_local(operand_var.data_type.clone());
                         // child will do the cmp
                         if !parent_is_logical {
                             let exit = exit_passdown.unwrap(); // (false_exit, true_exit) (consider `not`)
                             let final_exit = self.request_label();
                             instrs.push(IRInstr::Label(exit.1));
-                            instrs.push(IRInstr::Move(dest_var, MoveRValue::ConstInt(1)));
+                            instrs.push(IRInstr::Move(dest_var.clone(), MoveRValue::ConstInt(1)));
                             instrs.push(IRInstr::Goto(final_exit));
                             instrs.push(IRInstr::Label(exit.0));
-                            instrs.push(IRInstr::Move(dest_var, MoveRValue::ConstInt(0)));
+                            instrs.push(IRInstr::Move(dest_var.clone(), MoveRValue::ConstInt(0)));
                             instrs.push(IRInstr::Goto(final_exit));
                             instrs.push(IRInstr::Label(final_exit));
 
@@ -449,10 +372,7 @@ impl Generator {
                 };
                 (instrs, Some(dest_var))
             },
-            ExprValue::BinaryOp { lhs, op, rhs } => {
+            HirExprValue::BinaryOp { lhs, op, rhs } => {
-                let lhs_span = lhs.span;
-                let rhs_span = rhs.span;
-
                 // +--------+-------------------------+-------------------------+-------------------------+
                 // | parent | (true_exit, false_exit) | (true_exit, false_exit) | (true_exit, false_exit) |
                 // | self   | and(next)               | or(next)                | others                  |
@@ -494,44 +414,30 @@ impl Generator {
                 self.current_exit_label.push(lhs_exit_passdown);
                 let (mut instrs, left_var) = self.generate_expr(*lhs)?;
                 self.current_exit_label.pop();
-                if left_var.is_none() {
-                    self.diagnostic.add_from_ir_error(IRError::InvalidOperand(IRType::Void), lhs_span);
-                    return None;
-                }
                 let mut left_var = left_var.unwrap();
                 self.current_exit_label.push(rhs_exit_passdown);
                 let (right_instrs, right_var) = self.generate_expr(*rhs)?;
                 self.current_exit_label.pop();
-                if right_var.is_none() {
-                    self.diagnostic.add_from_ir_error(IRError::InvalidOperand(IRType::Void), rhs_span);
-                    return None;
-                }
                 let mut right_var = right_var.unwrap();
                 // check implicit convert
                 let convert_to;
                 if op.is_logical() {
                     // we dont really care since we use cmp
-                    convert_to = left_var.data_type;
+                    convert_to = left_var.data_type.clone();
                 } else {
-                    if let Some(ty) = IRType::get_elevate_result(left_var.data_type, right_var.data_type) {
+                    convert_to = IRType::get_elevate_result(&left_var.data_type, &right_var.data_type).unwrap();
-                        convert_to = ty;
-                    } else {
-                        self.diagnostic.add_from_ir_error(IRError::IncompatiableOperand(left_var.data_type, right_var.data_type), lhs_span);
-                        self.diagnostic.add_from_ir_error(IRError::IncompatiableOperand(left_var.data_type, right_var.data_type), rhs_span);
-                        return None;
-                    } 
                 }
                 // do implicit convert if needed
                 // TODO: further check
                 if !op.is_logical() && convert_to != left_var.data_type {
-                    let temp_var = self.var_manager.declare_temp(convert_to);
+                    let temp_var = self.var_manager.declare_temp(convert_to.clone());
-                    instrs.push(IRInstr::Move(temp_var, MoveRValue::Var(left_var)));
+                    instrs.push(IRInstr::Move(temp_var.clone(), MoveRValue::Var(left_var)));
                     left_var = temp_var;
                 }
                 let result_type;
                 match op {
                     AstBinaryOp::Add | AstBinaryOp::Sub | AstBinaryOp::Mul | AstBinaryOp::Div | AstBinaryOp::Mod => {
-                        result_type = left_var.data_type;
+                        result_type = left_var.data_type.clone();
                     },
                     AstBinaryOp::Equal | AstBinaryOp::NotEqual | AstBinaryOp::Less | AstBinaryOp::Greater | AstBinaryOp::LessEqual | AstBinaryOp::GreaterEqual 
                     | AstBinaryOp::And | AstBinaryOp::Or => {
@@ -565,17 +471,17 @@ impl Generator {
                 instrs.extend(right_instrs);
                 if !op.is_logical() && convert_to != right_var.data_type {
                     let temp_var = self.var_manager.declare_temp(convert_to);
-                    instrs.push(IRInstr::Move(temp_var, MoveRValue::Var(right_var)));
+                    instrs.push(IRInstr::Move(temp_var.clone(), MoveRValue::Var(right_var)));
                     right_var = temp_var;
                 }
                 if !op.is_logical() {
                     if let Some((true_exit, false_exit)) = parent_exit {
                         let final_exit = self.request_label();
                         instrs.push(IRInstr::Label(true_exit));
-                        instrs.push(IRInstr::Move(dest_var, MoveRValue::ConstInt(1)));
+                        instrs.push(IRInstr::Move(dest_var.clone(), MoveRValue::ConstInt(1)));
                         instrs.push(IRInstr::Goto(final_exit));
                         instrs.push(IRInstr::Label(false_exit));
-                        instrs.push(IRInstr::Move(dest_var, MoveRValue::ConstInt(0)));
+                        instrs.push(IRInstr::Move(dest_var.clone(), MoveRValue::ConstInt(0)));
                         instrs.push(IRInstr::Label(final_exit));
 
 
@@ -585,9 +491,9 @@ impl Generator {
                     return Some((instrs, Some(dest_var)));
                 } else {
                     if op.is_cmp() {
-                        instrs.push(IRInstr::Cmp(dest_var, VariableOrIntLit::Var(left_var), op.into(), VariableOrIntLit::Var(right_var)));
+                        instrs.push(IRInstr::Cmp(dest_var.clone(), VariableOrIntLit::Var(left_var), op.into(), VariableOrIntLit::Var(right_var)));
                     } else {
-                        instrs.push(IRInstr::Binary(dest_var, left_var, op.into(), right_var));
+                        instrs.push(IRInstr::Binary(dest_var.clone(), left_var, op.into(), right_var));
                     }
                 }
                 // if !op.is_logical() {
@@ -606,73 +512,84 @@ impl Generator {
                 // }
                 (instrs, Some(dest_var))
             },
-            ExprValue::FuncCall(func_name, args) => {
+            HirExprValue::FuncCall(func_id, args) => {
                 let mut instrs = vec![];
                 let mut arg_vars = vec![];
-                let func_def = if let Some(func_def) = self.function_map.get(&func_name) {
+                let func_def = self.ir_function(func_id);
-                    func_def
-                } else {
-                    self.diagnostic.add_from_ir_error(IRError::FunctionNotFound(func_name.clone()), expr.span);
-                    return None;
-                }.clone();
 
-                if args.len() < func_def.parameter_types.len() {
+                for arg in args.into_iter() {
-                    self.diagnostic.add_from_ir_error(IRError::TooFewArguments(func_def.parameter_types.len(), args.len()), expr.span);
-                    return None;
-                }
-                if args.len() > func_def.parameter_types.len() {
-                    self.diagnostic.add_from_ir_error(IRError::TooManyArguments(func_def.parameter_types.len(), args.len()), expr.span);
-                    return None;
-                }
-                let mut has_error = false;
-                for parameter_type in &func_def.parameter_types {
-                    if matches!(parameter_type, IRType::Void) {
-                        self.diagnostic.add_from_ir_error(IRError::InvalidParameterType(IRType::Void), expr.span);
-                        has_error = true;
-                    }
-                }
-                if has_error {
-                    return None;
-                }
-                for (i, arg) in args.into_iter().enumerate() {
                     self.current_exit_label.push(None);
                     let (arg_instrs, arg_var) = self.generate_expr(arg)?;
                     self.current_exit_label.pop();
-                    let parameter_type = func_def.parameter_types.get(i).unwrap();
-                    if *parameter_type != arg_var.map_or(IRType::Void, |v| v.data_type) {
-                        self.diagnostic.add_from_ir_error(IRError::TypeMismatch(*parameter_type, arg_var.map_or(IRType::Void, |v| v.data_type)), expr.span);
-                        has_error = true;
-                        continue;
-                    }
                     instrs.extend(arg_instrs);
                     arg_vars.push(arg_var.unwrap());
                 }
-                if has_error {
-                    return None;
-                }
                 let ret_variable = if matches!(func_def.return_type, IRType::Void) {
                     None
                 } else {
-                    Some(self.var_manager.declare_temp(func_def.return_type))
+                    Some(self.var_manager.declare_temp(func_def.return_type.clone()))
                 };
-                instrs.push(IRInstr::FuncCall(func_def.clone(), arg_vars, ret_variable));
+                instrs.push(IRInstr::FuncCall(func_def.clone(), arg_vars, ret_variable.clone()));
                 (instrs, ret_variable)
             }
         };
         if let Some((true_exit, false_exit)) = self.current_exit_label.last().cloned().flatten() {
             let cmp_var = self.var_manager.declare_temp(IRType::I1);
-            instrs.push(IRInstr::Cmp(cmp_var, VariableOrIntLit::Var(var.unwrap()), CmpOp::Ne, VariableOrIntLit::IntLit(0)));
+            instrs.push(IRInstr::Cmp(cmp_var.clone(), VariableOrIntLit::Var(var.clone().unwrap()), CmpOp::Ne, VariableOrIntLit::IntLit(0)));
             instrs.push(IRInstr::CondGoto(cmp_var, true_exit, false_exit));
             Some((instrs, var))
         } else {
             Some((instrs, var))
         }
     }
+
+    fn generate_lvalue(&mut self, expr: HirExpr) -> Option<(Vec<IRInstr>, Variable, bool)> {
+        match expr.value {
+            HirExprValue::Var(symbol) => {
+                let var = self.var_manager.get_symbol(symbol).unwrap();
+                Some((vec![], var, false))
+            }
+            HirExprValue::ArrayAccess { array, index } => {
+                let (instrs, addr) = self.generate_array_element_addr(*array, *index)?;
+                Some((instrs, addr, true))
+            }
+            _ => None,
+        }
+    }
+
+    fn generate_array_element_addr(&mut self, array: HirExpr, index: HirExpr) -> Option<(Vec<IRInstr>, Variable)> {
+        let elem_ty = array.ty.indexed_type().unwrap();
+        let elem_size = elem_ty.element_size_in_bytes();
+        let (mut instrs, base) = match array.value {
+            HirExprValue::Var(symbol) => {
+                let var = self.var_manager.get_symbol(symbol).unwrap();
+                if var.data_type.is_array() {
+                    let ptr = self.var_manager.declare_temp(var.data_type.decay_to_ptr().unwrap());
+                    (vec![IRInstr::Move(ptr.clone(), MoveRValue::Var(var))], ptr)
+                } else {
+                    (vec![], var)
+                }
+            }
+            HirExprValue::ArrayAccess { array, index } => self.generate_array_element_addr(*array, *index)?,
+            _ => self.generate_expr(array).map(|(instrs, var)| (instrs, var.unwrap()))?,
+        };
+        self.current_exit_label.push(None);
+        let (index_instrs, index_var) = self.generate_expr(index)?;
+        self.current_exit_label.pop();
+        instrs.extend(index_instrs);
+        let addr_ty = IRType::Ptr(Box::new(elem_ty.into()));
+        let dest = self.var_manager.declare_temp(addr_ty);
+        let elem_size_var = self.var_manager.declare_temp(IRType::I32);
+        let offset = self.var_manager.declare_temp(IRType::I32);
+        instrs.push(IRInstr::Move(elem_size_var.clone(), MoveRValue::ConstInt(elem_size as i32)));
+        instrs.push(IRInstr::Binary(offset.clone(), index_var.unwrap(), AstBinaryOp::Mul.into(), elem_size_var));
+        instrs.push(IRInstr::Binary(dest.clone(), base, AstBinaryOp::Add.into(), offset));
+        Some((instrs, dest))
+    }
 }
 
 struct VariableManager {
-    variable_map: BTreeMap<String, Vec<Variable>>,
+    variable_map: BTreeMap<SymbolId, Variable>,
-    scopes: Vec<BTreeSet<String>>,
     global_counter: usize,
     local_counter: usize,
     local_var_type: Vec<Variable>,
@@ -682,27 +599,12 @@ impl VariableManager {
     pub fn new() -> Self {
         Self {
             variable_map: BTreeMap::new(),
-            scopes: vec![BTreeSet::new()],
             global_counter: 0,
             local_counter: 0,
             local_var_type: vec![],
         }
     }
-    pub fn enter_scope(&mut self) {
+    fn declare_symbol(&mut self, symbol: SymbolId, var_type: VariableType, var_data_type: IRType) -> Variable {
-        self.scopes.push(BTreeSet::new());
-    }
-
-    pub fn exit_scope(&mut self) {
-        let variables = self.scopes.pop().unwrap();
-        for var in variables {
-            self.variable_map.get_mut(&var).unwrap().pop();
-        }
-    }
-
-    fn declare_variable(&mut self, name: &str, var_type: VariableType, var_data_type: IRType) -> Result<Variable, IRError> {
-        if self.scopes.last().unwrap().contains(name) {
-            return Err(IRError::VariableHasBeenDefined(name.to_string()));
-        }
         let variable = match var_type {
             VariableType::Global => {
                 let var = Variable { index: self.global_counter, var_type, data_type: var_data_type };
@@ -716,46 +618,40 @@ impl VariableManager {
             }
             _ => unreachable!(),
         };
-        self.variable_map.entry(name.to_string()).or_default().push(variable);
+        self.variable_map.insert(symbol, variable.clone());
-        self.scopes.last_mut().unwrap().insert(name.to_string());
         if matches!(var_type, VariableType::Local) {
-            self.local_var_type.push(variable);
+            self.local_var_type.push(variable.clone());
         }
-        Ok(variable)
+        variable
-    }
-    pub fn declare_gloabal(&mut self, name: &str, var_data_type: IRType) -> Result<Variable, IRError> {
-        self.declare_variable(name, VariableType::Global, var_data_type)
-    }
-    pub fn declare_local(&mut self, name: &str, var_data_type: IRType) -> Result<Variable, IRError> {
-        self.declare_variable(name, VariableType::Local, var_data_type)
     }
     pub fn declare_temp(&mut self, var_data_type: IRType) -> Variable {
         let var = Variable { index: self.local_counter, var_type: VariableType::Temp, data_type: var_data_type };
         self.local_counter += 1;
-        self.local_var_type.push(var);
+        self.local_var_type.push(var.clone());
         var
     }
     pub fn declare_unamed_local(&mut self, var_data_type: IRType) -> Variable {
         let var = Variable { index: self.local_counter, var_type: VariableType::Local, data_type: var_data_type };
         self.local_counter += 1;
-        self.local_var_type.push(var);
+        self.local_var_type.push(var.clone());
         var
     }
     pub fn declare_param_temp(&mut self, var_data_type: IRType, param_index: usize) -> Variable {
         let var = Variable { index: self.local_counter, var_type: VariableType::ParamTemp(param_index), data_type: var_data_type };
         self.local_counter += 1;
-        self.local_var_type.push(var);
+        self.local_var_type.push(var.clone());
         var
     }
     pub fn clear_local_counter(&mut self) {
         self.local_counter = 0;
         self.local_var_type.clear();
+        self.variable_map.retain(|_, var| matches!(var.var_type, VariableType::Global));
     }
     pub fn get_cur_func_variables(&self) -> Vec<Variable> {
         self.local_var_type.iter().cloned().collect()
     }
-    pub fn get_variable(&self, name: &str) -> Option<Variable> {
+    pub fn get_symbol(&self, symbol: SymbolId) -> Option<Variable> {
-        self.variable_map.get(name).and_then(|vars| vars.last()).cloned()
+        self.variable_map.get(&symbol).cloned()
     }
 
 }
@@ -769,6 +665,7 @@ mod tests {
     use std::io::Write;
     use crate::frontend::lexer::Lexer;
     use crate::frontend::parser::Parser;
+    use crate::sema::analyzer::Analyzer;
     use crate::utils::case_list::CaseList;
     use crate::utils::num_sequence::NumberSequence;
 
@@ -806,12 +703,14 @@ mod tests {
                 parser.diagnostics.print(&format!("{}", case_path.display()), &full_text);
                 is_error = true;
             }
-            let mut generator = Generator::new();
+            let mut analyzer = Analyzer::new();
-            let ir = generator.emit(compile_unit);
+            let hir = analyzer.analyze(compile_unit);
-            if !generator.diagnostic.is_empty() {
+            if !analyzer.get_diagnostics().is_empty() {
-                generator.diagnostic.print(&format!("{}", case_path.display()), &full_text);
+                analyzer.get_diagnostics().print(&format!("{}", case_path.display()), &full_text);
                 is_error = true;
             }
+            let mut generator = Generator::new(&analyzer);
+            let ir = generator.emit(hir);
             let mut ir_file = File::create(format!("output/{}.ir", case_name)).unwrap();
             for instr in ir {
                 writeln!(ir_file, "{}", instr).unwrap();
@@ -838,4 +737,8 @@ mod tests {
     fn test_func() {
         test_case("12-13,58-60");
     }
+    #[test]
+    fn test_array() {
+        test_case("4-7,11,42,71,74-78,82,84,86,90,95,96,100,101,103");
+    }
 }

src/ir/types.rs

@@ -30,6 +30,8 @@ pub enum IRInstr {
     CondGoto(Variable, usize, usize), // condition, true label, false label
     Label(usize),
     Move(Variable, MoveRValue),
+    Load(Variable, Variable),
+    Store(Variable, Variable),
 }
 
 impl Display for IRInstr {
@@ -47,7 +49,9 @@ impl Display for IRInstr {
                 }
             }
             IRInstr::Move(dest, src) => write!(f, "{} = {}", dest, src),
-            IRInstr::Declare(var) => write!(f, "declare {} {}", var.data_type, var),
+            IRInstr::Load(dest, addr) => write!(f, "{} = *{}", dest, addr),
+            IRInstr::Store(addr, value) => write!(f, "*{} = {}", addr, value),
+            IRInstr::Declare(var) => write!(f, "declare {}", var.to_decl_string()),
             IRInstr::DefineFunc(func, args, body) => {
                 let body_str = body.iter().map(|instr| format!("  {}", instr)).collect::<Vec<_>>().join("\n");
                 write!(f, "define {} {{\n{}\n}}", func.to_decl_string(args), body_str)
@@ -59,11 +63,13 @@ impl Display for IRInstr {
         }
     }
 }
-#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub enum IRType {
     I32,
     I1,
     Void,
+    Ptr(Box<IRType>),
+    Array(Box<IRType>, Vec<usize>),
 }
 impl IRType {
     pub fn size_in_bytes(&self) -> usize {
@@ -71,13 +77,47 @@ impl IRType {
             IRType::I32 => 4,
             IRType::I1 => 1,
             IRType::Void => 0,
+            IRType::Ptr(_) => 4,
+            IRType::Array(elem, dims) => elem.size_in_bytes() * dims.iter().product::<usize>(),
         }
     }
 
-    pub fn get_elevate_result(lhs: IRType, rhs: IRType) -> Option<IRType> {
+    pub fn is_array(&self) -> bool {
+        matches!(self, IRType::Array(_, _))
+    }
+
+    pub fn decay_to_ptr(&self) -> Option<IRType> {
+        match self {
+            IRType::Array(elem, dims) => {
+                let pointee = if dims.len() == 1 {
+                    (**elem).clone()
+                } else {
+                    IRType::Array(elem.clone(), dims[1..].to_vec())
+                };
+                Some(IRType::Ptr(Box::new(pointee)))
+            }
+            _ => None,
+        }
+    }
+
+    pub fn element_type(&self) -> Option<IRType> {
+        match self {
+            IRType::Array(elem, dims) => {
+                if dims.len() == 1 {
+                    Some((**elem).clone())
+                } else {
+                    Some(IRType::Array(elem.clone(), dims[1..].to_vec()))
+                }
+            }
+            IRType::Ptr(elem) => Some((**elem).clone()),
+            _ => None,
+        }
+    }
+
+    pub fn get_elevate_result(lhs: &IRType, rhs: &IRType) -> Option<IRType> {
         if lhs == rhs {
-            Some(lhs)
+            Some(lhs.clone())
-        } else if (lhs == IRType::I32 && rhs == IRType::I1) || (lhs == IRType::I1 && rhs == IRType::I32) {
+        } else if (*lhs == IRType::I32 && *rhs == IRType::I1) || (*lhs == IRType::I1 && *rhs == IRType::I32) {
             Some(IRType::I32)
         } else {
             None
@@ -90,6 +130,30 @@ impl Display for IRType {
             IRType::I32 => write!(f, "i32"),
             IRType::Void => write!(f, "void"),
             IRType::I1 => write!(f, "i1"),
+            IRType::Ptr(elem) => write!(f, "{}*", elem),
+            IRType::Array(elem, dims) => {
+                write!(f, "{}", elem)?;
+                for dim in dims {
+                    write!(f, "[{}]", dim)?;
+                }
+                Ok(())
+            }
+        }
+    }
+}
+impl IRType {
+    pub fn base_type_and_dims(&self) -> (&IRType, &[usize]) {
+        match self {
+            IRType::Array(elem, dims) => (elem.as_ref(), dims.as_slice()),
+            _ => (self, &[]),
+        }
+    }
+
+    pub fn scalar_base_type(&self) -> &IRType {
+        match self {
+            IRType::Array(elem, _) => elem.scalar_base_type(),
+            IRType::Ptr(elem) => elem.scalar_base_type(),
+            _ => self,
         }
     }
 }
@@ -120,7 +184,7 @@ pub enum VariableType {
     Local,
     Temp,
 }
-#[derive(Clone, Copy)]
+#[derive(Clone)]
 pub struct Variable {
     // pub name: String,
     pub index: usize,
@@ -160,6 +224,19 @@ impl Display for Variable {
         write!(f, "{}{}", prefix, self.index)
     }
 }
+impl Variable {
+    pub fn to_decl_string(&self) -> String {
+        match &self.data_type {
+            IRType::Array(_, _) => {
+                let (base_type, dims) = self.data_type.base_type_and_dims();
+                let dims_str = dims.iter().map(|dim| format!("[{}]", dim)).collect::<Vec<_>>().join("");
+                format!("{} {}{}", base_type, self, dims_str)
+            }
+            IRType::Ptr(_) => format!("{}* {}", self.data_type.scalar_base_type(), self),
+            _ => format!("{} {}", self.data_type, self),
+        }
+    }
+}
 #[derive(Debug, Clone)]
 pub struct Function {
     pub name: String,
@@ -175,7 +252,11 @@ impl Function {
     }
 
     pub fn to_decl_string(&self, args: &Vec<Variable>) -> String {
-        let params_str = args.iter().zip(self.parameter_types.iter()).map(|(arg, param_type)| format!("{} {}", param_type, arg)).collect::<Vec<_>>().join(", ");
+        let params_str = args.iter().zip(self.parameter_types.iter()).map(|(arg, param_type)| {
+            let (base_type, dims) = param_type.base_type_and_dims();
+            let dims_str = dims.iter().map(|dim| format!("[{}]", dim)).collect::<Vec<_>>().join("");
+            format!("{} {}{}", base_type, arg, dims_str)
+        }).collect::<Vec<_>>().join(", ");
         format!("{} @{}({})", self.return_type, self.name, params_str)
     }
 }

src/main.rs

@@ -5,12 +5,13 @@ mod backend;
 mod utils;
 mod diagnostic;
 mod err;
+mod sema;
 
 use std::{fs::File, io::BufRead};
 
 use clap::Parser as ArgParser;
 
-use crate::{frontend::{lexer::Lexer, parser::Parser}, ir::generator::Generator};
+use crate::{frontend::{lexer::Lexer, parser::Parser}, ir::generator::Generator, sema::analyzer::Analyzer};
 use crate::backend::generator::Generator as ASMGerenerator;
 /// Simple minic compiler built by Rust
 #[derive(ArgParser, Debug)]
@@ -78,11 +79,13 @@ fn main() {
     if !parser.diagnostics.is_empty() {
         parser.diagnostics.print(&format!("{}", source_path.display()), &full_text);
     }
-    let mut generator = Generator::new();
+    let mut analyzer = Analyzer::new();
-    let ir = generator.emit(compile_unit);
+    let hir = analyzer.analyze(compile_unit);
-    if !generator.get_diagnostics().is_empty() {
+    if !analyzer.get_diagnostics().is_empty() {
-        generator.get_diagnostics().print(&format!("{}", source_path.display()), &full_text);
+        analyzer.get_diagnostics().print(&format!("{}", source_path.display()), &full_text);
     }
+    let mut generator = Generator::new(&analyzer);
+    let ir = generator.emit(hir);
     if args.output_ir {
         if let Some(output_path) = args.output {
             match std::fs::write(&output_path, ir.iter().map(|instr| instr.to_string()).collect::<Vec<_>>().join("\n")) {

src/sema/analyzer.rs

@@ -0,0 +1,529 @@
+use std::collections::BTreeMap;
+
+use crate::{
+    ast::types::{
+        ArrayDimension, BinaryOp, BlockStmt, BreakStmt, CompileUnit, ContinueStmt, Expr, ExprValue, FuncDeclStmt,
+        GlobalDeclStmt, IfElseBranch, IfStmt, ReturnStmt, Statement, VarDeclStmt, WhileStmt,
+    },
+    diagnostic::{span::Span, Diagnositics},
+    sema::{
+        err::SemaError,
+        hir::{
+            HirBlockStmt, HirBreakStmt, HirCompileUnit, HirContinueStmt, HirExpr, HirExprValue,
+            HirFuncDeclStmt, HirGlobalDeclStmt, HirIfElseBranch, HirIfStmt, HirParam,
+            HirReturnStmt, HirStatement, HirVarDeclStmt, HirVarDeclStmtValue, HirWhileStmt,
+        },
+        symbol::{FunctionId, FunctionSig, SymbolId, SymbolKind, SymbolTable},
+        types::SemaType,
+    },
+};
+
+pub struct Analyzer {
+    symbols: SymbolTable,
+    function_map: BTreeMap<String, FunctionId>,
+    functions: Vec<FunctionSig>,
+    current_func_return_type: Option<SemaType>,
+    diagnostic: Diagnositics,
+    loop_depth: usize,
+}
+
+impl Analyzer {
+    pub fn new() -> Self {
+        let mut analyzer = Self {
+            symbols: SymbolTable::new(),
+            function_map: BTreeMap::new(),
+            functions: vec![],
+            current_func_return_type: None,
+            diagnostic: Diagnositics::new(),
+            loop_depth: 0,
+        };
+        analyzer.declare_builtin_func("putint", vec![SemaType::I32], SemaType::Void);
+        analyzer.declare_builtin_func("putch", vec![SemaType::I32], SemaType::Void);
+        analyzer.declare_builtin_func("getint", vec![], SemaType::I32);
+        analyzer
+    }
+
+    pub fn analyze(&mut self, compile_unit: CompileUnit) -> HirCompileUnit {
+        self.analyze_compile_unit(compile_unit)
+    }
+
+    pub fn get_diagnostics(&self) -> &Diagnositics {
+        &self.diagnostic
+    }
+
+    pub fn get_symbol_type(&self, symbol: SymbolId) -> SemaType {
+        self.symbols.get_symbol(symbol).ty.clone()
+    }
+
+    pub fn get_symbol_kind(&self, symbol: SymbolId) -> SymbolKind {
+        self.symbols.get_symbol(symbol).kind
+    }
+
+    pub fn get_function_sig(&self, function: FunctionId) -> &FunctionSig {
+        &self.functions[function.0]
+    }
+
+    fn declare_builtin_func(&mut self, name: &str, parameter_types: Vec<SemaType>, return_type: SemaType) {
+        let id = FunctionId(self.functions.len());
+        let sig = FunctionSig {
+            id,
+            name: name.to_string(),
+            return_type,
+            parameter_types,
+        };
+        self.function_map.insert(name.to_string(), id);
+        self.functions.push(sig);
+    }
+
+    fn add_error(&mut self, error: SemaError, span: Span) {
+        self.diagnostic.add_from_error(error, span);
+    }
+
+    fn analyze_compile_unit(&mut self, compile_unit: CompileUnit) -> HirCompileUnit {
+        let mut global_decls = vec![];
+        for decl in compile_unit.global_decls {
+            match decl {
+                GlobalDeclStmt::VarDecl(var_decl) => {
+                    global_decls.push(HirGlobalDeclStmt::VarDecl(self.analyze_var_decl(var_decl, SymbolKind::Global)));
+                }
+                GlobalDeclStmt::FuncDecl(func_decl) => {
+                    if let Some(func_decl) = self.analyze_func_decl(func_decl) {
+                        global_decls.push(HirGlobalDeclStmt::FuncDecl(func_decl));
+                    }
+                }
+            }
+        }
+        HirCompileUnit { global_decls }
+    }
+
+    fn analyze_var_decl(&mut self, var_decl: VarDeclStmt, kind: SymbolKind) -> HirVarDeclStmt {
+        let base_type: SemaType = var_decl.data_type.into();
+        let mut values = vec![];
+        for value in var_decl.values {
+            let data_type = self.build_var_type(base_type.clone(), &value.dimensions, false);
+            match self.symbols.declare_variable(&value.name, kind, data_type) {
+                Ok(symbol) => values.push(HirVarDeclStmtValue {
+                    symbol,
+                    name_span: value.name_span,
+                }),
+                Err(e) => self.add_error(e, value.name_span),
+            }
+        }
+        HirVarDeclStmt {
+            values,
+            data_type: base_type,
+            type_span: var_decl.type_span,
+        }
+    }
+
+    fn analyze_func_decl(&mut self, func_decl: FuncDeclStmt) -> Option<HirFuncDeclStmt> {
+        if self.function_map.contains_key(&func_decl.name) {
+            self.add_error(SemaError::FunctionHasBeenDefined(func_decl.name.clone()), func_decl.name_span);
+            return None;
+        }
+
+        let function_id = FunctionId(self.functions.len());
+        let mut parameter_types = vec![];
+        for param in &func_decl.params {
+            parameter_types.push(self.build_var_type(param.param_type.into(), &param.dimensions, true));
+        }
+        let return_type: SemaType = func_decl.return_type.into();
+        let sig = FunctionSig {
+            id: function_id,
+            name: func_decl.name.clone(),
+            return_type: return_type.clone(),
+            parameter_types,
+        };
+        self.function_map.insert(func_decl.name.clone(), function_id);
+        self.functions.push(sig.clone());
+
+        self.current_func_return_type = Some(return_type);
+        self.symbols.enter_scope();
+
+        let mut params = vec![];
+        for param in func_decl.params {
+            let param_type = self.build_var_type(param.param_type.into(), &param.dimensions, true);
+            match self.symbols.declare_variable(&param.name, SymbolKind::Param, param_type.clone()) {
+                Ok(symbol) => params.push(HirParam {
+                    symbol,
+                    param_type,
+                    name_span: param.name_span,
+                    type_span: param.type_span,
+                }),
+                Err(e) => self.add_error(e, param.name_span),
+            }
+        }
+
+        let body = self.analyze_block_stmt(func_decl.body);
+        self.symbols.exit_scope();
+        self.current_func_return_type = None;
+
+        Some(HirFuncDeclStmt {
+            sig,
+            params,
+            body,
+            ret_type_span: func_decl.ret_type_span,
+            name_span: func_decl.name_span,
+        })
+    }
+
+    fn build_var_type(&mut self, base_type: SemaType, dimensions: &[ArrayDimension], is_param: bool) -> SemaType {
+        if dimensions.is_empty() {
+            return base_type;
+        }
+        let mut dims = vec![];
+        for (i, dimension) in dimensions.iter().enumerate() {
+            match &dimension.value {
+                Some(expr) => {
+                    if let ExprValue::IntLit(value) = expr.value {
+                        if value > 0 {
+                            dims.push(value as usize);
+                        } else {
+                            self.add_error(SemaError::InvalidArrayDimension, dimension.span);
+                        }
+                    } else {
+                        self.add_error(SemaError::InvalidArrayDimension, dimension.span);
+                    }
+                }
+                None if is_param && i == 0 => {}
+                None => self.add_error(SemaError::InvalidArrayDimension, dimension.span),
+            }
+        }
+        if is_param {
+            let pointee_type = if dims.is_empty() {
+                base_type
+            } else {
+                SemaType::Array(Box::new(base_type), dims)
+            };
+            SemaType::Ptr(Box::new(pointee_type))
+        } else {
+            SemaType::Array(Box::new(base_type), dims)
+        }
+    }
+
+    fn analyze_block_stmt(&mut self, block_stmt: BlockStmt) -> HirBlockStmt {
+        let mut statements = vec![];
+        for stmt in block_stmt.statements {
+            if let Some(stmt) = self.analyze_statement(stmt) {
+                statements.push(stmt);
+            }
+        }
+        HirBlockStmt { statements }
+    }
+
+    fn analyze_statement(&mut self, stmt: Statement) -> Option<HirStatement> {
+        match stmt {
+            Statement::Return(stmt) => Some(HirStatement::Return(self.analyze_return_stmt(stmt))),
+            Statement::If(stmt) => Some(HirStatement::If(self.analyze_if_stmt(stmt))),
+            Statement::While(stmt) => Some(HirStatement::While(self.analyze_while_stmt(stmt))),
+            Statement::Break(stmt) => Some(HirStatement::Break(self.analyze_break_stmt(stmt))),
+            Statement::Continue(stmt) => Some(HirStatement::Continue(self.analyze_continue_stmt(stmt))),
+            Statement::Block(stmt) => {
+                self.symbols.enter_scope();
+                let block = self.analyze_block_stmt(stmt);
+                self.symbols.exit_scope();
+                Some(HirStatement::Block(block))
+            }
+            Statement::Expr(expr) => self.analyze_expr(expr).map(HirStatement::Expr),
+            Statement::VarDecl(var_decl) => Some(HirStatement::VarDecl(self.analyze_var_decl(var_decl, SymbolKind::Local))),
+        }
+    }
+
+    fn analyze_return_stmt(&mut self, return_stmt: ReturnStmt) -> HirReturnStmt {
+        let expected_ty = self.current_func_return_type.clone().unwrap();
+        let value = match return_stmt.value {
+            Some(expr) => {
+                if expected_ty == SemaType::Void {
+                    self.add_error(SemaError::ReturnExpressionOnVoidFunction, return_stmt.span);
+                    None
+                } else {
+                    match self.analyze_expr(expr) {
+                        Some(expr) => {
+                            if expr.ty == SemaType::Void {
+                                self.add_error(SemaError::InvalidOperand(SemaType::Void), return_stmt.span);
+                            } else if !self.type_matches(&expected_ty, &expr.ty) {
+                                self.add_error(SemaError::TypeMismatch(expected_ty.clone(), expr.ty.clone()), return_stmt.span);
+                            }
+                            Some(expr)
+                        }
+                        None => None,
+                    }
+                }
+            }
+            None => {
+                if expected_ty != SemaType::Void {
+                    self.add_error(SemaError::TypeMismatch(expected_ty, SemaType::Void), return_stmt.span);
+                }
+                None
+            }
+        };
+        HirReturnStmt {
+            value,
+            span: return_stmt.span,
+        }
+    }
+
+    fn analyze_if_stmt(&mut self, if_stmt: IfStmt) -> HirIfStmt {
+        let condition = self.analyze_condition_expr(if_stmt.condition);
+        let then_branch = self.analyze_block_stmt(if_stmt.then_branch);
+        let mut ifelse_branch = vec![];
+        for branch in if_stmt.ifelse_branch {
+            let IfElseBranch { condition, then_branch } = branch;
+            ifelse_branch.push(HirIfElseBranch {
+                condition: self.analyze_condition_expr(condition),
+                then_branch: self.analyze_block_stmt(then_branch),
+            });
+        }
+        let else_branch = if_stmt.else_branch.map(|block| self.analyze_block_stmt(block));
+        HirIfStmt {
+            condition,
+            then_branch,
+            ifelse_branch,
+            else_branch,
+        }
+    }
+
+    fn analyze_while_stmt(&mut self, while_stmt: WhileStmt) -> HirWhileStmt {
+        let condition = self.analyze_condition_expr(while_stmt.condition);
+        self.loop_depth += 1;
+        let body = self.analyze_block_stmt(while_stmt.body);
+        self.loop_depth -= 1;
+        HirWhileStmt {
+            condition,
+            body,
+        }
+    }
+
+    fn analyze_break_stmt(&mut self, stmt: BreakStmt) -> HirBreakStmt {
+        if self.loop_depth == 0 {
+            self.add_error(SemaError::BreakOutsideLoop, stmt.span);
+        }
+        HirBreakStmt { span: stmt.span }
+    }
+
+    fn analyze_continue_stmt(&mut self, stmt: ContinueStmt) -> HirContinueStmt {
+        if self.loop_depth == 0 {
+            self.add_error(SemaError::ContinueOutsideLoop, stmt.span);
+        }
+        HirContinueStmt { span: stmt.span }
+    }
+
+    fn analyze_condition_expr(&mut self, expr: Expr) -> HirExpr {
+        let span = expr.span;
+        match self.analyze_expr(expr) {
+            Some(expr) => {
+                if expr.ty == SemaType::Void {
+                    self.add_error(SemaError::InvalidOperand(SemaType::Void), span);
+                }
+                expr
+            }
+            None => HirExpr {
+                value: HirExprValue::IntLit(0),
+                ty: SemaType::I32,
+                span,
+            },
+        }
+    }
+
+    fn analyze_expr(&mut self, expr: Expr) -> Option<HirExpr> {
+        let span = expr.span;
+        match expr.value {
+            ExprValue::IntLit(value) => Some(HirExpr {
+                value: HirExprValue::IntLit(value),
+                ty: SemaType::I32,
+                span,
+            }),
+            ExprValue::Var(name) => {
+                let symbol = match self.symbols.get_variable(&name) {
+                    Some(symbol) => symbol,
+                    None => {
+                        self.add_error(SemaError::VariableNotFound(name), span);
+                        return None;
+                    }
+                };
+                Some(HirExpr {
+                    value: HirExprValue::Var(symbol),
+                    ty: self.symbols.get_symbol(symbol).ty.clone(),
+                    span,
+                })
+            }
+            ExprValue::Assign { lvalue, rvalue } => self.analyze_assign_expr(*lvalue, *rvalue, span),
+            ExprValue::ArrayAccess { array, index } => self.analyze_array_access_expr(*array, *index, span),
+            ExprValue::UnaryOp { op, operand } => {
+                let operand_span = operand.span;
+                let operand = self.analyze_expr(*operand)?;
+                if operand.ty == SemaType::Void {
+                    self.add_error(SemaError::InvalidOperand(SemaType::Void), operand_span);
+                    return None;
+                }
+                let ty = match op {
+                    crate::ast::types::UnaryOp::Not => SemaType::I1,
+                    _ => operand.ty.clone(),
+                };
+                Some(HirExpr {
+                    value: HirExprValue::UnaryOp {
+                        op,
+                        operand: Box::new(operand),
+                    },
+                    ty,
+                    span,
+                })
+            }
+            ExprValue::BinaryOp { lhs, op, rhs } => self.analyze_binary_expr(*lhs, op, *rhs, span),
+            ExprValue::FuncCall(func_name, args) => self.analyze_func_call_expr(func_name, args, span),
+        }
+    }
+
+    fn analyze_assign_expr(&mut self, lvalue: Expr, rvalue: Expr, span: Span) -> Option<HirExpr> {
+        if !matches!(lvalue.value, ExprValue::Var(_) | ExprValue::ArrayAccess { .. }) {
+            self.add_error(SemaError::InvalidAssignmentTarget, lvalue.span);
+            return None;
+        }
+        let lvalue = self.analyze_expr(lvalue)?;
+        if lvalue.ty.is_array_like() {
+            self.add_error(SemaError::InvalidAssignmentTarget, lvalue.span);
+            return None;
+        }
+        let rvalue_span = rvalue.span;
+        let rvalue = self.analyze_expr(rvalue)?;
+        if rvalue.ty == SemaType::Void {
+            self.add_error(SemaError::InvalidOperand(SemaType::Void), rvalue_span);
+            return None;
+        }
+        if !self.type_matches(&lvalue.ty, &rvalue.ty) {
+            self.add_error(SemaError::TypeMismatch(lvalue.ty.clone(), rvalue.ty.clone()), span);
+            return None;
+        }
+        Some(HirExpr {
+            ty: lvalue.ty.clone(),
+            value: HirExprValue::Assign {
+                lvalue: Box::new(lvalue),
+                rvalue: Box::new(rvalue),
+            },
+            span,
+        })
+    }
+
+    fn analyze_binary_expr(&mut self, lhs: Expr, op: BinaryOp, rhs: Expr, span: Span) -> Option<HirExpr> {
+        let lhs_span = lhs.span;
+        let rhs_span = rhs.span;
+        let lhs = self.analyze_expr(lhs)?;
+        let rhs = self.analyze_expr(rhs)?;
+        if !lhs.ty.is_scalar() {
+            self.add_error(SemaError::InvalidOperand(lhs.ty.clone()), lhs_span);
+            return None;
+        }
+        if !rhs.ty.is_scalar() {
+            self.add_error(SemaError::InvalidOperand(rhs.ty.clone()), rhs_span);
+            return None;
+        }
+
+        let result_ty = if op.is_logical() {
+            SemaType::I1
+        } else {
+            match SemaType::get_elevate_result(&lhs.ty, &rhs.ty) {
+                Some(_) if op.is_cmp() => SemaType::I1,
+                Some(ty) => ty,
+                None => {
+                    self.add_error(SemaError::IncompatiableOperand(lhs.ty.clone(), rhs.ty.clone()), lhs_span);
+                    self.add_error(SemaError::IncompatiableOperand(lhs.ty.clone(), rhs.ty.clone()), rhs_span);
+                    return None;
+                }
+            }
+        };
+
+        Some(HirExpr {
+            value: HirExprValue::BinaryOp {
+                lhs: Box::new(lhs),
+                op,
+                rhs: Box::new(rhs),
+            },
+            ty: result_ty,
+            span,
+        })
+    }
+
+    fn analyze_func_call_expr(&mut self, func_name: String, args: Vec<Expr>, span: Span) -> Option<HirExpr> {
+        let func_id = match self.function_map.get(&func_name).cloned() {
+            Some(func_id) => func_id,
+            None => {
+                self.add_error(SemaError::FunctionNotFound(func_name), span);
+                return None;
+            }
+        };
+        let func_def = self.functions[func_id.0].clone();
+
+        if args.len() < func_def.parameter_types.len() {
+            self.add_error(SemaError::TooFewArguments(func_def.parameter_types.len(), args.len()), span);
+            return None;
+        }
+        if args.len() > func_def.parameter_types.len() {
+            self.add_error(SemaError::TooManyArguments(func_def.parameter_types.len(), args.len()), span);
+            return None;
+        }
+
+        let mut has_error = false;
+        for parameter_type in &func_def.parameter_types {
+            if matches!(parameter_type, SemaType::Void) {
+                self.add_error(SemaError::InvalidParameterType(SemaType::Void), span);
+                has_error = true;
+            }
+        }
+        if has_error {
+            return None;
+        }
+
+        let mut hir_args = vec![];
+        for (i, arg) in args.into_iter().enumerate() {
+            let arg = self.analyze_expr(arg)?;
+            let parameter_type = func_def.parameter_types[i].clone();
+            if !self.type_matches(&parameter_type, &arg.ty) {
+                self.add_error(SemaError::TypeMismatch(parameter_type, arg.ty.clone()), span);
+                has_error = true;
+                continue;
+            }
+            hir_args.push(arg);
+        }
+        if has_error {
+            return None;
+        }
+
+        Some(HirExpr {
+            value: HirExprValue::FuncCall(func_id, hir_args),
+            ty: func_def.return_type,
+            span,
+        })
+    }
+
+    fn analyze_array_access_expr(&mut self, array: Expr, index: Expr, span: Span) -> Option<HirExpr> {
+        let index_span = index.span;
+        let array = self.analyze_expr(array)?;
+        let index = self.analyze_expr(index)?;
+        if !index.ty.is_scalar() {
+            self.add_error(SemaError::InvalidOperand(index.ty.clone()), index_span);
+            return None;
+        }
+        let ty = match array.ty.indexed_type() {
+            Some(ty) => ty,
+            None => {
+                self.add_error(SemaError::NotSubscriptable, span);
+                return None;
+            }
+        };
+        Some(HirExpr {
+            value: HirExprValue::ArrayAccess {
+                array: Box::new(array),
+                index: Box::new(index),
+            },
+            ty,
+            span,
+        })
+    }
+
+    fn type_matches(&self, expected: &SemaType, actual: &SemaType) -> bool {
+        if expected == actual {
+            return true;
+        }
+        matches!((expected, actual), (SemaType::Ptr(expected_elem), SemaType::Array(_, _)) if actual.indexed_type().is_some_and(|ty| &ty == expected_elem.as_ref()))
+    }
+}

src/sema/err.rs

@@ -0,0 +1,39 @@
+use thiserror::Error;
+
+use crate::sema::types::SemaType;
+
+#[derive(Debug, Clone, PartialEq, Eq, Error)]
+pub enum SemaError {
+    #[error("variable `{0}` not found")]
+    VariableNotFound(String),
+    #[error("variable `{0}` has already been defined")]
+    VariableHasBeenDefined(String),
+    #[error("function `{0}` not found")]
+    FunctionNotFound(String),
+    #[error("function `{0}` has already been defined")]
+    FunctionHasBeenDefined(String),
+    #[error("incompatible operands: {0} and {1}")]
+    IncompatiableOperand(SemaType, SemaType),
+    #[error("invalid operand type: {0}")]
+    InvalidOperand(SemaType),
+    #[error("too few arguments: expected {0}, got {1}")]
+    TooFewArguments(usize, usize),
+    #[error("too many arguments: expected {0}, got {1}")]
+    TooManyArguments(usize, usize),
+    #[error("type mismatch, expected {0}, got {1}")]
+    TypeMismatch(SemaType, SemaType),
+    #[error("invalid assignment target")]
+    InvalidAssignmentTarget,
+    #[error("break statement outside of loop")]
+    BreakOutsideLoop,
+    #[error("continue statement outside of loop")]
+    ContinueOutsideLoop,
+    #[error("invalid parameter type: {0}")]
+    InvalidParameterType(SemaType),
+    #[error("return expression on void function")]
+    ReturnExpressionOnVoidFunction,
+    #[error("array dimension must be a positive integer literal")]
+    InvalidArrayDimension,
+    #[error("subscripted value is not an array or pointer")]
+    NotSubscriptable,
+}

src/sema/hir.rs

@@ -0,0 +1,110 @@
+use crate::{ast::types::{BinaryOp, UnaryOp}, diagnostic::span::Span, sema::{symbol::{FunctionId, FunctionSig, SymbolId}, types::SemaType}};
+
+pub struct HirCompileUnit {
+    pub global_decls: Vec<HirGlobalDeclStmt>,
+}
+
+pub enum HirGlobalDeclStmt {
+    VarDecl(HirVarDeclStmt),
+    FuncDecl(HirFuncDeclStmt),
+}
+
+pub struct HirVarDeclStmt {
+    pub values: Vec<HirVarDeclStmtValue>,
+    pub data_type: SemaType,
+    pub type_span: Span,
+}
+
+pub struct HirVarDeclStmtValue {
+    pub symbol: SymbolId,
+    pub name_span: Span,
+}
+
+pub struct HirFuncDeclStmt {
+    pub sig: FunctionSig,
+    pub params: Vec<HirParam>,
+    pub body: HirBlockStmt,
+    pub ret_type_span: Span,
+    pub name_span: Span,
+}
+
+pub struct HirParam {
+    pub symbol: SymbolId,
+    pub param_type: SemaType,
+    pub name_span: Span,
+    pub type_span: Span,
+}
+
+pub struct HirBlockStmt {
+    pub statements: Vec<HirStatement>,
+}
+
+pub enum HirStatement {
+    Return(HirReturnStmt),
+    Block(HirBlockStmt),
+    Expr(HirExpr),
+    VarDecl(HirVarDeclStmt),
+    If(HirIfStmt),
+    While(HirWhileStmt),
+    Break(HirBreakStmt),
+    Continue(HirContinueStmt),
+}
+
+pub struct HirIfStmt {
+    pub condition: HirExpr,
+    pub then_branch: HirBlockStmt,
+    pub ifelse_branch: Vec<HirIfElseBranch>,
+    pub else_branch: Option<HirBlockStmt>,
+}
+
+pub struct HirIfElseBranch {
+    pub condition: HirExpr,
+    pub then_branch: HirBlockStmt,
+}
+
+pub struct HirWhileStmt {
+    pub condition: HirExpr,
+    pub body: HirBlockStmt,
+}
+
+pub struct HirBreakStmt {
+    pub span: Span,
+}
+
+pub struct HirContinueStmt {
+    pub span: Span,
+}
+
+pub struct HirReturnStmt {
+    pub value: Option<HirExpr>,
+    pub span: Span,
+}
+
+pub struct HirExpr {
+    pub value: HirExprValue,
+    pub ty: SemaType,
+    pub span: Span,
+}
+
+pub enum HirExprValue {
+    IntLit(i64),
+    Var(SymbolId),
+    ArrayAccess {
+        array: Box<HirExpr>,
+        index: Box<HirExpr>,
+    },
+    BinaryOp {
+        lhs: Box<HirExpr>,
+        op: BinaryOp,
+        rhs: Box<HirExpr>,
+    },
+    UnaryOp {
+        op: UnaryOp,
+        operand: Box<HirExpr>,
+    },
+    FuncCall(FunctionId, Vec<HirExpr>),
+    Assign {
+        lvalue: Box<HirExpr>,
+        rvalue: Box<HirExpr>,
+    },
+}

src/sema/mod.rs

@@ -0,0 +1,5 @@
+pub mod analyzer;
+pub mod err;
+pub mod hir;
+pub mod symbol;
+pub mod types;

src/sema/symbol.rs

@@ -0,0 +1,83 @@
+use std::collections::{BTreeMap, BTreeSet};
+
+use crate::sema::{err::SemaError, types::SemaType};
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct SymbolId(pub usize);
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum SymbolKind {
+    Global,
+    Local,
+    Param,
+}
+
+#[derive(Clone, Debug)]
+pub struct Symbol {
+    pub id: SymbolId,
+    pub name: String,
+    pub ty: SemaType,
+    pub kind: SymbolKind,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct FunctionId(pub usize);
+
+#[derive(Clone, Debug)]
+pub struct FunctionSig {
+    pub id: FunctionId,
+    pub name: String,
+    pub return_type: SemaType,
+    pub parameter_types: Vec<SemaType>,
+}
+
+pub struct SymbolTable {
+    symbols: Vec<Symbol>,
+    variable_map: BTreeMap<String, Vec<SymbolId>>,
+    scopes: Vec<BTreeSet<String>>,
+}
+
+impl SymbolTable {
+    pub fn new() -> Self {
+        Self {
+            symbols: vec![],
+            variable_map: BTreeMap::new(),
+            scopes: vec![BTreeSet::new()],
+        }
+    }
+
+    pub fn enter_scope(&mut self) {
+        self.scopes.push(BTreeSet::new());
+    }
+
+    pub fn exit_scope(&mut self) {
+        let variables = self.scopes.pop().unwrap();
+        for var in variables {
+            self.variable_map.get_mut(&var).unwrap().pop();
+        }
+    }
+
+    pub fn declare_variable(&mut self, name: &str, kind: SymbolKind, ty: SemaType) -> Result<SymbolId, SemaError> {
+        if self.scopes.last().unwrap().contains(name) {
+            return Err(SemaError::VariableHasBeenDefined(name.to_string()));
+        }
+        let id = SymbolId(self.symbols.len());
+        self.symbols.push(Symbol {
+            id,
+            name: name.to_string(),
+            ty,
+            kind,
+        });
+        self.variable_map.entry(name.to_string()).or_default().push(id);
+        self.scopes.last_mut().unwrap().insert(name.to_string());
+        Ok(id)
+    }
+
+    pub fn get_variable(&self, name: &str) -> Option<SymbolId> {
+        self.variable_map.get(name).and_then(|vars| vars.last()).cloned()
+    }
+
+    pub fn get_symbol(&self, id: SymbolId) -> &Symbol {
+        &self.symbols[id.0]
+    }
+}

src/sema/types.rs

@@ -0,0 +1,95 @@
+use std::fmt::Display;
+
+use crate::{ast::types::Type as AstType, ir::types::IRType};
+
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum SemaType {
+    I32,
+    I1,
+    Void,
+    Array(Box<SemaType>, Vec<usize>),
+    Ptr(Box<SemaType>),
+}
+
+impl SemaType {
+    pub fn get_elevate_result(lhs: &SemaType, rhs: &SemaType) -> Option<SemaType> {
+        if lhs == rhs {
+            Some(lhs.clone())
+        } else if (*lhs == SemaType::I32 && *rhs == SemaType::I1) || (*lhs == SemaType::I1 && *rhs == SemaType::I32) {
+            Some(SemaType::I32)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_scalar(&self) -> bool {
+        matches!(self, SemaType::I32 | SemaType::I1)
+    }
+
+    pub fn is_array_like(&self) -> bool {
+        matches!(self, SemaType::Array(_, _) | SemaType::Ptr(_))
+    }
+
+    pub fn indexed_type(&self) -> Option<SemaType> {
+        match self {
+            SemaType::Array(elem, dims) => {
+                if dims.len() == 1 {
+                    Some((**elem).clone())
+                } else {
+                    Some(SemaType::Array(elem.clone(), dims[1..].to_vec()))
+                }
+            }
+            SemaType::Ptr(elem) => Some((**elem).clone()),
+            _ => None,
+        }
+    }
+
+    pub fn element_size_in_bytes(&self) -> usize {
+        match self {
+            SemaType::I32 => 4,
+            SemaType::I1 => 1,
+            SemaType::Void => 0,
+            SemaType::Array(elem, dims) => elem.element_size_in_bytes() * dims.iter().product::<usize>(),
+            SemaType::Ptr(_) => 4,
+        }
+    }
+}
+
+impl Display for SemaType {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            SemaType::I32 => write!(f, "i32"),
+            SemaType::I1 => write!(f, "i1"),
+            SemaType::Void => write!(f, "void"),
+            SemaType::Array(elem, dims) => {
+                write!(f, "{}", elem)?;
+                for dim in dims {
+                    write!(f, "[{}]", dim)?;
+                }
+                Ok(())
+            }
+            SemaType::Ptr(elem) => write!(f, "{}*", elem),
+        }
+    }
+}
+
+impl From<AstType> for SemaType {
+    fn from(value: AstType) -> Self {
+        match value {
+            AstType::Int => SemaType::I32,
+            AstType::Void => SemaType::Void,
+        }
+    }
+}
+
+impl From<SemaType> for IRType {
+    fn from(value: SemaType) -> Self {
+        match value {
+            SemaType::I32 => IRType::I32,
+            SemaType::I1 => IRType::I1,
+            SemaType::Void => IRType::Void,
+            SemaType::Array(elem, dims) => IRType::Array(Box::new((*elem).into()), dims),
+            SemaType::Ptr(elem) => IRType::Ptr(Box::new((*elem).into())),
+        }
+    }
+}