buggy

src/main.cpp

@@ -1,8 +1,11 @@
 #include <cassert>
+#include <functional>
 #include <iostream>
 #include <istream>
 #include <memory>
+#include <queue>
 #include <string>
+#include <type_traits>
 #include <unordered_map>
 #include <unordered_set>
 #include <variant>
@@ -21,7 +24,7 @@ struct Applyable : Data {
 };
 
 struct Cell {
-    Data *d;
+    Data *d = nullptr;
     size_t cdr = 0;
 };
 
@@ -57,7 +60,7 @@ struct Nil : SelfEval {
 
 
 struct Fork : Data {
-    size_t data;
+    size_t data = 0;
     size_t Get() {
         return data;
     }
@@ -65,34 +68,36 @@ struct Fork : Data {
 
 struct Lambda : Data {
     Env env;
-    size_t args;
-    size_t f;
+    size_t args = 0;
+    size_t f = 0;
 };
 
+
+
 enum class locs { EVAL_START, EVAL_OP_FIN, EVAL_TOP_ARG, APPLY };
 
 enum class special_indef_eval {NONE, PROGN, IF_BEGIN, FORCE_RETURN_NEXT_ARG};
 
 
 struct Registers {
-    size_t Exp;
-    size_t args_front;
-    size_t args_current;
-    size_t args_left;
+    size_t Exp = 0;
+    size_t args_front = 0;
+    size_t args_current = 0;
+    size_t args_left = 0;
 
     // general registers
-    size_t A;
-    size_t B;
-    size_t C;
-    size_t D;
+    size_t A = 0;
+    size_t B = 0;
+    size_t C = 0;
+    size_t D = 0;
 
     bool argflag = false;
 
-	size_t op;
+	size_t op = 0;
 
     locs RP;
 
-    size_t R;
+    size_t R = 0;
     Env E;
 
 	special_indef_eval screen = special_indef_eval::NONE;
@@ -104,19 +109,19 @@ struct Machine {
 	size_t mempty_pos = 1;
 
 
-	int activebank = 0;
-    std::vector<Cell> bank0;
-	std::vector<Cell> bank1;
+	// int activebank = 0;
+    // std::vector<Cell> bank0;
+	// std::vector<Cell> bank1;
 
-	std::vector<Cell>& mem;
-	std::vector<Cell>& mem_empty;
+	std::vector<Cell> mem;
+	std::vector<Cell> mem_empty;
 
 
     std::vector<Registers> stack;
 
     Registers reg;
 
-    Machine(size_t max) : bank0(max) , bank1(max), mem(bank0), mem_empty(bank1) {
+    Machine(size_t max) : mem(max), mem_empty(max) {
         maxCells = max;
         reg.E.builtin.insert("+");
         reg.E.builtin.insert("-");
@@ -408,7 +413,9 @@ struct Machine {
 
     size_t newCell() {
         if (freepos >= maxCells) {
-			throw "OOM";
+			GC();
+			return newCell();
+			//throw "OOM";
         }
         auto nc = freepos;
         freepos += 1;
@@ -426,19 +433,119 @@ struct Machine {
     }
 
 
+	void GCMoveElem(std::reference_wrapper<size_t> from) {
+		size_t& v = from.get();
+		// no need to move if the pointer is null
+		if (v == 0) { 
+			return;
+		}
 
-	// size_t MoveThingAtAddr(size_t loc) {
-	// 	auto nc = newCellInEmpty();
-	// 	mem_empty[nc] = mem[loc];
-	// 	mem[loc].cdr = maxCells + nc;
-	// 	return nc;
-	// }
+		if (mem[v].cdr < maxCells) {
+			auto nloc = newCellInEmpty();
+			// copy
+			mem_empty[nloc] = mem[v];
+
+			// leave heart
+			mem[v].cdr = nloc + maxCells;
+
+			// update orignal
+			v = nloc;
+		} else { // if already moved
+			std::cout << "v: " << v << std::endl;
+			v = mem[v].cdr - maxCells;
+		}
+	}
+
+	// stop and copy gc
+
+	void addRegsToGCQueue(std::vector<std::reference_wrapper<size_t>>& queue, Registers& regs) {
+		queue.push_back(std::ref(regs.Exp));
+		queue.push_back(std::ref(regs.args_front));
+		queue.push_back(std::ref(regs.args_current));
+		queue.push_back(std::ref(regs.args_left));
+
+		queue.push_back(std::ref(regs.A));
+		queue.push_back(std::ref(regs.B));
+		queue.push_back(std::ref(regs.C));
+		queue.push_back(std::ref(regs.D));
+
+		queue.push_back(std::ref(regs.op));
+
+		queue.push_back(std::ref(regs.R));
+		addEnvToGCQueue(queue, regs.E);
+	}
+
+	void addEnvToGCQueue(std::vector<std::reference_wrapper<size_t>>& queue, Env& env) {
+		for (auto& def : env.userdef) {
+			queue.push_back(std::ref(def.second));
+		}
+	}
+	
+	void GC() {
+		std::cout << "GCING" << std::endl;
+		std::vector<std::reference_wrapper<size_t>> queue;
+
+		// add all known to queue
+		addRegsToGCQueue(queue, reg);
+
+		for (auto& e : stack) {
+			addRegsToGCQueue(queue, e);
+		}
+
+		// cheney's alg
+
+		// copy all root nodes over to to-space
+
+		for (size_t i = 0; i < queue.size(); i++) {
+			GCMoveElem(queue[i]);
+		}
+
+		size_t scan = 1;
+
+		std::unordered_set<Data*> handled;
+
+		while (scan != mempty_pos) { // scan not at blank cell
+			// move the cdr
+			GCMoveElem(mem_empty[scan].cdr);
+
+			if (handled.contains(mem_empty[scan].d)) {} 
+			else {
+				handled.insert(mem_empty[scan].d);
+				if (Fork * f = dynamic_cast<Fork*>(mem_empty[scan].d)) {
+					GCMoveElem(std::ref(f->data));
+				} else if (Lambda * l = dynamic_cast<Lambda*>(mem_empty[scan].d)) {
+					for (auto& def : l->env.userdef) {
+						GCMoveElem(std::ref(def.second));
+					}
+					GCMoveElem(std::ref(l->args));
+					GCMoveElem(std::ref(l->f));
+				}
+			}
+
+			scan++;
+
+		}
+
+		handled.clear();
 
-	// // stop and copy gc
-	// void GC() {
-	// 	std::vector<
 		
-	// }
+		for (size_t i = 1; i < mempty_pos; i++) {
+			handled.insert(mem_empty[i].d);
+		}
+
+		for (size_t i = 1; i < mem.size(); i++) {
+			if (mem[i].cdr < maxCells && !handled.contains(mem[i].d)) {
+				handled.insert(mem[i].d);
+				delete mem[i].d;
+			}
+			mem[i].d = nullptr;
+			mem[i].cdr = 0;
+		}
+
+		mem.swap(mem_empty);
+		freepos = mempty_pos;
+		mempty_pos = 1;
+	}
 
     size_t newCell(Data *d) {
         auto t = newCell();
@@ -561,7 +668,7 @@ struct Machine {
 };
 
 int main() {
-    auto m = Machine(1000);
+    auto m = Machine(20);
 
 
     Cell c;
@@ -593,6 +700,7 @@ int main() {
 		std::cout << err << std::endl;
 	}
     std::cout << "out of loop" << std::endl;
+	std::cout << "freepos: " << m.freepos << " out of: " << m.maxCells << std::endl;
 
     c.d = m.mem[m.reg.R].d;
     m.ListPrint(c);