Operations support with temp expressions values in stack

compiler/CodeGenVisitor.cpp

@@ -27,6 +27,11 @@ std::any CodeGenVisitor::visitProg(ifccParser::ProgContext *ctx) {
 std::any CodeGenVisitor::visitStmt(ifccParser::StmtContext *ctx) {
     std::cout << "    ;" << ctx->getText() << "\n";
     return this->visitChildren(ctx);
+
+}
+std::any CodeGenVisitor::visitReturn_stmt(ifccParser::Return_stmtContext *ctx) {
+    this->visit(ctx->expr());
+    return 0;
 }
 
 // Declaration pass already filled the symbol table: nothing to do here.
@@ -37,9 +42,9 @@ std::any CodeGenVisitor::visitDecl_stmt(ifccParser::Decl_stmtContext *ctx) {
 // Assign a value to a variable: evaluate val, store on stack, mark as initialized.
 std::any CodeGenVisitor::visitSet_stmt(ifccParser::Set_stmtContext *ctx) {
     std::string name = ctx->VAR_NAME()->getText();
-    int offset = symbolTable->getOffset(currentScope(), name);
+    int offset = symbolTable->getOffset(currentScope(), name) + stackOffset;
 
-    this->visit(ctx->val());
+    this->visit(ctx->expr());
 
 #ifdef __APPLE__
     std::cout << "    str w0, [sp, #" << offset << "]\n";
@@ -64,7 +69,7 @@ std::any CodeGenVisitor::visitVal(ifccParser::ValContext *ctx) {
     }
 
     std::string name = ctx->VAR_NAME()->getText();
-    int offset = symbolTable->getOffset(currentScope(), name);
+    int offset = symbolTable->getOffset(currentScope(), name) + stackOffset;
     symbolTable->isInitialized(currentScope(), name); // emits warning if needed
 
 #ifdef __APPLE__
@@ -76,7 +81,38 @@ std::any CodeGenVisitor::visitVal(ifccParser::ValContext *ctx) {
     return offset;
 }
 
-std::any CodeGenVisitor::visitReturn_stmt(ifccParser::Return_stmtContext *ctx) {
-    this->visit(ctx->val());
+std::any CodeGenVisitor::visitExpr(ifccParser::ExprContext *ctx) {
+    // Parenthesized expression or single val: delegate directly
+    if (ctx->expr().size() == 1) {
+        return this->visit(ctx->expr(0));
+    }
+    if (ctx->expr().empty()) {
+        return this->visit(ctx->val());
+    }
+
+    // Evaluate left, push result onto stack to survive nested sub-expressions
+    this->visit(ctx->expr(0));
+#ifdef __APPLE__
+    std::cout << "    str w0, [sp, #-16]!\n"; // sp -= 16, push -> [sp]
+#else
+    std::cout << "    pushq %rax\n";
+#endif
+    stackOffset += 16;
+
+    // Evaluate right, result in w0 / eax
+    this->visit(ctx->expr(1));
+
+#ifdef __APPLE__
+    std::cout << "    ldr w8, [sp], #16\n";  // pop -> w8, sp += 16
+    if (ctx->MUL())      std::cout << "    mul w0, w8, w0\n";
+    else if (ctx->DIV()) std::cout << "    sdiv w0, w8, w0\n";
+    else if (ctx->ADD()) std::cout << "    add w0, w8, w0\n";
+    else if (ctx->SUB()) std::cout << "    sub w0, w8, w0\n";
+#else
+
+#endif
+
+    stackOffset -= 16;
     return 0;
 }
+

compiler/CodeGenVisitor.h

@@ -10,6 +10,7 @@
 class CodeGenVisitor : public ifccBaseVisitor {
 	SymbolTable *symbolTable;            // shared, not owned
 	std::vector<std::string> scopeStack; // navigation state, owned by this visitor
+	int stackOffset = 0; // When adding additional information to the stack such as temp expressions results, sp gets decremented and this offset keeps track of how much
 
 	std::string currentScope() const { return scopeStack.back(); }
 
@@ -28,4 +29,6 @@ public:
 	std::any visitSet_stmt(ifccParser::Set_stmtContext *ctx) override;
 
 	std::any visitVal(ifccParser::ValContext *ctx) override;
+
+	std::any visitExpr(ifccParser::ExprContext *ctx) override;
 };

compiler/DeclarationVisitor.cpp

@@ -22,15 +22,3 @@ std::any DeclarationVisitor::visitDecl_stmt(ifccParser::Decl_stmtContext *ctx) {
     }
     return 0;
 }
-
-std::any DeclarationVisitor::visitSet_stmt(ifccParser::Set_stmtContext *ctx) {
-    return 0;
-}
-
-std::any DeclarationVisitor::visitVal(ifccParser::ValContext *ctx) {
-    return 0;
-}
-
-std::any DeclarationVisitor::visitReturn_stmt(ifccParser::Return_stmtContext *ctx) {
-    return 0;
-}

compiler/DeclarationVisitor.h

@@ -27,13 +27,23 @@ public:
 
 	std::any visitStmt(ifccParser::StmtContext *ctx) override;
 
-	std::any visitReturn_stmt(ifccParser::Return_stmtContext *ctx) override;
+	std::any visitReturn_stmt(ifccParser::Return_stmtContext *ctx) override {
+		return 0;
+	}
 
 	std::any visitDecl_stmt(ifccParser::Decl_stmtContext *ctx) override;
 
-	std::any visitSet_stmt(ifccParser::Set_stmtContext *ctx) override;
+	std::any visitSet_stmt(ifccParser::Set_stmtContext *ctx) override {
+		return 0;
+	}
 
-	std::any visitVal(ifccParser::ValContext *ctx) override;
+	std::any visitVal(ifccParser::ValContext *ctx) override {
+		return 0;
+	}
+
+	std::any visitExpr(ifccParser::ExprContext *ctx) override {
+		return 0;
+	}
 };
 
 

compiler/ifcc.g4

@@ -6,12 +6,27 @@ prog: 'int' 'main' '(' ')' '{' stmt* '}' ;
 
 stmt: decl_stmt | set_stmt | return_stmt ;
 
-return_stmt: RETURN val ';' ;
+return_stmt: RETURN expr ';' ;
 
 decl_stmt: 'int' (VAR_NAME ',')* VAR_NAME ';' ;
-set_stmt: VAR_NAME '=' val ';' ;
+set_stmt: VAR_NAME '=' expr ';' ;
 
-val: CONST | VAR_NAME ;
+val: CONST | VAR_NAME;
+
+expr: expr MUL expr
+    | expr DIV expr
+    | expr ADD expr
+    | expr SUB expr
+    | '(' expr ')'
+    | val
+    ;
+
+
+
+MUL : '*' ;
+DIV : '/' ;
+ADD : '+' ;
+SUB : '-' ;
 
 RETURN : 'return' ;
 CONST : [0-9]+ ;

testfiles/5_expr.c

@@ -0,0 +1,7 @@
+int main() {
+    int x;
+    int y;
+    x = 42;
+    y = 8;
+    return (x + y) * (x - y) / (x * y);
+}