Yoinked over the garbage collector.

src/GC/include/heap.hpp

@@ -0,0 +1,100 @@
+#pragma once
+
+#include <assert.h>
+#include <iostream>
+#include <setjmp.h>
+#include <stdlib.h>
+#include <vector>
+
+#include "chunk.hpp"
+#include "profiler.hpp"
+
+#define HEAP_SIZE 2097152 //65536
+#define FREE_THRESH (uint) 100000
+#define DEBUG
+
+namespace GC
+{
+	/**
+	 * Flags for the collect overlead for conditional
+	 * collection (mark/sweep/free/all).
+	*/
+	enum CollectOption {
+		MARK=0x1,
+		SWEEP=0x2,
+		MARK_SWEEP = 0x3,
+		FREE=0x4,
+		COLLECT_ALL=0x7
+	};
+
+	/**
+	 * The heap class to represent the heap for the
+	 * garbage collection. The heap is a singleton
+	 * instance and can be retrieved by Heap::the()
+	 * inside the heap class. The heap is represented
+	 * by a char array of size 65536 and can enable
+	 * a profiler to track the actions on the heap.
+	*/
+	class Heap
+	{
+	private:
+		Heap() : m_heap(static_cast<char *>(malloc(HEAP_SIZE))) {}
+
+		~Heap()
+		{
+			std::free((char *)m_heap);
+		}
+
+		char *const m_heap;
+		size_t m_size {0};
+		// static Heap *m_instance {nullptr};
+		uintptr_t *m_stack_top {nullptr};
+		bool m_profiler_enable {false};
+
+		std::vector<Chunk *> m_allocated_chunks;
+		std::vector<Chunk *> m_freed_chunks;
+
+		static bool profiler_enabled();
+		// static Chunk *get_at(std::vector<Chunk *> &list, size_t n);
+		void collect();
+		void sweep(Heap &heap);
+		Chunk *try_recycle_chunks(size_t size);
+		void free(Heap &heap);
+		void free_overlap(Heap &heap);
+		void mark(uintptr_t *start, const uintptr_t *end, std::vector<Chunk *> &worklist);
+		void print_line(Chunk *chunk);
+		void print_worklist(std::vector<Chunk *> &list);
+		void mark_step(uintptr_t start, uintptr_t end, std::vector<Chunk *> &worklist);
+
+		// Temporary
+		Chunk *try_recycle_chunks_new(size_t size);
+		void free_overlap_new(Heap &heap);
+
+	public:
+		/**
+		 * These are the only five functions which are exposed
+		 * as the API for LLVM. At the absolute start of the
+		 * program the developer has to call init() to ensure
+		 * that the address of the topmost stack frame is
+		 * saved as the limit for scanning the stack in collect.
+		 */
+
+		static Heap &the();
+		static void init();
+		static void dispose();
+		static void *alloc(size_t size);
+		void set_profiler(bool mode);
+
+		// Stop the compiler from generating copy-methods
+		Heap(Heap const&) = delete;
+		Heap& operator=(Heap const&) = delete;
+
+#ifdef DEBUG
+		void collect(CollectOption flags); // conditional collection
+		void check_init();		  // print dummy things
+		void print_contents();	  // print dummy things
+		void print_allocated_chunks(Heap *heap); // print the contents in m_allocated_chunks
+		void print_summary();
+#endif
+	};
+}