From 2644480b9e5bf50464a15925994f95f3126235e5 Mon Sep 17 00:00:00 2001
From: ridethepig <protonghost@163.com>
Date: Sat, 1 Apr 2023 16:51:03 +0800
Subject: [PATCH] Add GC support

---
 assignments/PA5/cgen.cc    | 19 +++++++++++++++----
 assignments/PA5/example.cl |  2 ++
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/assignments/PA5/cgen.cc b/assignments/PA5/cgen.cc
index 4b46a43..616fb95 100644
--- a/assignments/PA5/cgen.cc
+++ b/assignments/PA5/cgen.cc
@@ -356,6 +356,11 @@ static void emit_gc_check(char *source, ostream &s) {
   s << JAL << "_gc_check" << endl;
 }
 
+static void emit_gc_assign(int offset, ostream &s) {
+  emit_addiu(A1, SELF, offset * WORD_SIZE, s);
+  emit_gc_assign(s);
+}
+
 /*
   |  ........  |
   |------------|
@@ -737,7 +742,7 @@ void CgenClassTable::gen_init_code() {
     for (auto i = 0U; i < attrs->size(); ++i) {
       auto attr_pair = (*attrs)[i];
       loctab.add(LocationTableItem(attr_pair.second->name, Attribute,
-                                    i + DEFAULT_OBJFIELDS));
+                                   i + DEFAULT_OBJFIELDS));
     }
     for (auto i = 0U; i < attrs->size(); ++i) {
       auto attr_pair = (*attrs)[i];
@@ -754,9 +759,11 @@ void CgenClassTable::gen_init_code() {
       this->expr_type_decl = attr_pair.second->type_decl;
       attr_pair.second->init->code(str, this);
       emit_store(ACC, i + DEFAULT_OBJFIELDS, SELF, str);
+      if (cgen_Memmgr != GC_NOGC)
+        emit_gc_assign(i + DEFAULT_OBJFIELDS, str);
     }
     loctab.exitscope();
-    emit_move(ACC, SELF, str); 
+    emit_move(ACC, SELF, str);
     // remember to place the initialized object back to $a0, other code rely on
     // this behavior
     emit_procedure_footer(0, str);
@@ -1240,8 +1247,11 @@ void assign_class::code(ostream &s, CgenClassTable *classtab) {
     emit_store(ACC, loc->offset, FP, s);
   } else {
     emit_store(ACC, loc->offset, SELF, s);
+    if (cgen_Memmgr != GC_NOGC)
+      emit_gc_assign(loc->offset, s);
   }
 }
+
 /*
   static dispatch is a little bit simpler than normal dispatch
   Intuitively, first evaluate all the parameter expression and push stack. Note
@@ -1262,7 +1272,7 @@ void static_dispatch_class::code(ostream &s, CgenClassTable *classtab) {
     auto actual_expr = this->actual->nth(actual_i);
     actual_expr->code(s, classtab);
     emit_push(ACC, s); // push param to stack
-    ++ nparams;
+    ++nparams;
   }
   this->expr->code(s, classtab);
   auto label_dispatch = classtab->alloc_label_index();
@@ -1301,7 +1311,7 @@ void dispatch_class::code(ostream &s, CgenClassTable *classtab) {
     auto actual_expr = this->actual->nth(actual_i);
     actual_expr->code(s, classtab);
     emit_push(ACC, s); // push param to stack
-    ++ nparams;
+    ++nparams;
   }
   this->expr->code(s, classtab);
   auto label_dispatch = classtab->alloc_label_index();
@@ -1332,6 +1342,7 @@ void dispatch_class::code(ostream &s, CgenClassTable *classtab) {
   // call the method whose address is in $t1, with self object in $a0
   emit_jalr(T1, s);
   rel_stack_depth -= nparams;
+  // caller doesn't pop the params, so we need to manual set the stack depth
 }
 
 /*
diff --git a/assignments/PA5/example.cl b/assignments/PA5/example.cl
index 9205019..7da6f73 100644
--- a/assignments/PA5/example.cl
+++ b/assignments/PA5/example.cl
@@ -37,8 +37,10 @@ class C inherits A {
   method_3(x1: Int, x2: A, x3: String) : Object {
     {
       x1 <- x1 + 00010 - x1 / 10;
+      attr_C_1 <- x3;
       x2 <- x2.method_common(x1);
       x3 <- x3.concat("schade");
+      attr_C_0 <- x1;
     }
   };
   method_2(x1: Bool, x2: C) : Object {