Started testing the GC

Co-authored-by: ValterMiari <ValterMiari@users.noreply.github.com>

src/GC/Makefile

@@ -0,0 +1,22 @@
+CC = clang++
+PWD = /home/virre/dev/systemF/org/language/src/GC/include
+CFLAGS = -Wall -Wextra -v -std=gnu++20 -stdlib=libc++ -I
+
+heap:
+	$(CC) $(CFLAGS)$(PWD) lib/heap.cpp
+
+h_test:
+	rm -f tests/h_test.out
+	$(CC) $(CFLAGS)$(PWD) tests/h_test.cpp lib/heap.cpp -o tests/h_test.out
+
+h_test_vg:
+	rm -f tests/h_test.out
+	$(CC) $(CFLAGS)$(PWD) -g tests/h_test.cpp lib/heap.cpp -o tests/h_test.out
+
+linker:
+	rm -f tests/linker.out
+	$(CC) $(CFLAGS)$(PWD) tests/linker.cpp lib/heap.cpp -o tests/linker.out
+
+linker_vg:
+	rm -f tests/linker.out
+	$(CC) $(CFLAGS)$(PWD) -g tests/linker.cpp lib/heap.cpp -o tests/linker.out

src/GC/include/chunk.hpp

@@ -8,7 +8,7 @@ namespace GC {
   
   struct Chunk {
     bool marked;
-    void *start;
+    uintptr_t *start;
     size_t size;
   };
 

src/GC/include/heap.hpp

@@ -5,7 +5,6 @@
 #include <setjmp.h>
 #include <stdlib.h>
 #include <vector>
-using namespace std;
 
 #include "chunk.hpp"
 
@@ -14,22 +13,6 @@ using namespace std;
 namespace GC {
 
   class Heap {
-  public:
-
-    // Singleton
-    static Heap &the() {
-      if (m_instance)
-	      return *m_instance;
-      m_instance = new Heap();
-      return *m_instance;
-    }
-
-    ~Heap() {
-      free((char *)m_heap);
-    }
-
-    void *alloc(size_t size);
-    void print_contents();
 
   private:
 
@@ -40,10 +23,10 @@ namespace GC {
     }
 
     void collect();
-    void compact();
+    void sweep();
+    // void compact();
     void mark(uintptr_t *start, const uintptr_t *end, std::vector<Chunk *> worklist);
-
-    bool compareChunks(Chunk *c1, Chunk *c2);
+    void print_line(Chunk *chunk);
 
     inline static Heap *m_instance = nullptr;
     const char *m_heap;
@@ -53,5 +36,30 @@ namespace GC {
     std::vector<Chunk *> m_allocated_chunks;
     std::vector<Chunk *> m_freed_chunks;
 
+  public:
+
+    // Singleton
+    static Heap &the() {
+      if (m_instance)
+	      return *m_instance;
+      m_instance = new Heap();
+      return *m_instance;
+    }
+
+    static Heap *the2() {
+      if (m_instance)
+        return m_instance;
+      m_instance = new Heap();
+      return m_instance;
+    }
+
+    // BEWARE only for testing, this should be adressed
+/*     ~Heap() {
+      free((char *)m_heap);
+    } */
+
+    void *alloc(size_t size);
+    void print_contents();
+    void force_collect();
   };
 }

src/GC/lib/heap.cpp

@@ -1,5 +1,3 @@
-#pragma once
-
 #include <algorithm>
 #include <assert.h>
 #include <cstring>
@@ -9,7 +7,7 @@
 #include <stdlib.h>
 #include <vector>
 
-#include "include/heap.hpp"
+#include "heap.hpp"
 
 namespace GC {
 
@@ -53,7 +51,7 @@ namespace GC {
     // Om inga free chunks finns, skapa ny chunk
     auto new_chunk = new Chunk;
     new_chunk->size = size;
-    new_chunk->start = (void *)m_heap + m_size;
+    new_chunk->start = (uintptr_t *)m_heap + m_size;
 
     m_size += size;
 
@@ -62,47 +60,68 @@ namespace GC {
     return new_chunk->start;
   }
 
-  bool compareChunks(Chunk *c1, Chunk *c2) {
-    return c1->start < c2->start;
-  }
-
   void Heap::collect() {
 
     // get the frame adress, whwere local variables and saved registers are located
     auto stack_start = reinterpret_cast<uintptr_t *>(__builtin_frame_address(0));
     // looking at 10 stack frames back
-    auto stack_end = reinterpret_cast<const uintptr_t *>(__builtin_frame_address(10));
+    const uintptr_t *stack_end = (uintptr_t *)0; //reinterpret_cast<const uintptr_t *>(__builtin_frame_address(10));
     auto work_list = m_allocated_chunks;
     mark(stack_start, stack_end, work_list);
 
-    compact();
+    sweep();
+
+    // compact();
+
+    // BELOW SHOULD BE INCLUDED (commented only for tests, to see which objects freed)
     
     //release free chunks
-    while (m_freed_chunks.size()) {
+    /* while (m_freed_chunks.size()) {
       auto chunk_pointer = m_freed_chunks.back();
       m_freed_chunks.pop_back();
-      delete chunk_pointer;
-    }
+      delete chunk_pointer; // deletes chunk object, doesn't free memory to the OS
+    } */
   }
 
-  void Heap::compact() {
-
-    // sort alloced_chunks by their start-addresses
-    std::sort(m_allocated_chunks.begin(), m_allocated_chunks.end(), compareChunks);
-    
-    // move all chunks to the start of the heap
-    auto heap_curr = (char *)m_heap;
-    for (auto space : m_allocated_chunks) {
-      if (space->start != heap_curr) {
-        memmove(heap_curr, space->start, space->size);
-        space->start = heap_curr;
-        heap_curr += space->size;
-      } else {
-        heap_curr += space->size;
+  // Not optimal for now, it doesn't have to loop over all objects
+  // but mark needs some refinements before this can be optimised
+  void Heap::sweep() {
+    // assert(false && "NOT IMPLEMENTED");
+    for (size_t i = 0; i < m_allocated_chunks.size(); i++) {
+      auto chunk = m_allocated_chunks.at(i);
+      if (chunk->marked == false) {
+        m_allocated_chunks.erase(m_allocated_chunks.begin() + i);
+        m_freed_chunks.push_back(chunk);
       } 
     }
   }
 
+  void Heap::force_collect() {
+    Heap::collect();
+  }
+  
+  // dead code
+  // void Heap::compact() {
+
+  //   // sort alloced_chunks by their start-addresses
+  //   std::sort(m_allocated_chunks.begin(), m_allocated_chunks.end(), [](Chunk *c1, Chunk *c2){
+  //     return c1->start < c2->start;
+  //   });
+    
+  //   // move all chunks to the start of the heap
+  //   auto heap_curr = (uintptr_t *)m_heap; // (char *)m_heap
+  //   for (auto space : m_allocated_chunks) {
+  //     if (space->start != heap_curr) {
+  //       memmove(heap_curr, space->start, space->size);
+  //       space->start = heap_curr;
+  //       heap_curr += space->size;
+  //     } else {
+  //       heap_curr += space->size;
+  //     }
+  //   }
+  // }
+
+  // return the worklist filtered on mark = true
   void Heap::mark(uintptr_t *start, const uintptr_t *end, std::vector<Chunk*> work_list) {
     for (; start < end; start++) { // to find adresses thats in the worklist
       for (size_t i = 0; i < work_list.size(); i++) { // fix this
@@ -120,18 +139,26 @@ namespace GC {
   }
 
   // For testing purposes
-  void print_line(bool marked, void *start, size_t size) {
-    std::cout << "Marked: " << marked << "\nStart adr: " << start << "\nSize" << size << std::endl;
+  void Heap::print_line(Chunk *chunk) {
+    std::cout << "Marked: " << chunk->marked << "\nStart adr: " << chunk->start << "\nSize: " << chunk->size << " B" << std::endl;
   }
 
   void Heap::print_contents() {
+    if (m_allocated_chunks.size()) {
       std::cout << "ALLOCATED CHUNKS" << std::endl;
       for (auto chunk : m_allocated_chunks) {
-        print_line(chunk->marked, chunk->start, chunk->size);
+          print_line(chunk);
       }
+    } else {
+      std::cout << "NO ALLOCATIONS" << std::endl;
+    }
+    if (m_freed_chunks.size()) {
       std::cout << "FREED CHUNKS" << std::endl;
       for (auto fchunk : m_freed_chunks) {
-        print_line(fchunk->marked, fchunk->start, fchunk->size);
+          print_line(fchunk);
+      }
+    } else {
+      std::cout << "NO FREED CHUNKS" << std::endl;
     }      
   }
 }

src/GC/tests/alloc_free.cpp

@@ -0,0 +1,29 @@
+#include <stdio.h>
+
+#include "heap.hpp"
+
+struct Obj {
+    int a;
+    int b;
+    int c;
+};
+
+int main() {
+    GC::Heap *heap = GC::Heap::the2();
+    Obj *obj;
+
+    for (int i = 0; i < 4; i++) {
+        obj = static_cast<Obj *>(heap->alloc(sizeof(Obj)));
+        obj->a = i * i + 1;
+        obj->b = i * i + 2;
+        obj->c = i * i + 3;
+    }
+
+    // heap->force_collect();
+
+    std::cout << obj->a << ", " << obj->b << ", " << obj->c << std::endl;
+
+    //delete heap;
+
+    return 0;
+}

src/GC/tests/h_test.cpp

@@ -1,16 +1,23 @@
-#include "../include/heap.hpp"
+#include "heap.hpp"
 
-GC::Heap gc;
+GC::Heap *gc = GC::Heap::the2();
 
 void init() {
-    gc = GC::Heap::the(); // pointer to the heap
-    std::vector<int> live_int_vec(100);
-    std::vector<int> dead_int_vec(100);
-    gc.alloc(sizeof(live_int_vec));
-    gc.alloc(sizeof(dead_int_vec));
+    std::vector<int> live_int_vec{1, 2, 3, 4, 5};
+    std::vector<int> dead_int_vec(10, 1);
+    int *a_ptr;
+    int a = 10;
+    a_ptr = &a;
+    auto temp1 = gc->alloc(sizeof(a_ptr));
+    auto temp2 = gc->alloc(sizeof(live_int_vec));
+    auto temp3 = gc->alloc(sizeof(dead_int_vec));
+    a_ptr = nullptr;
 }
 
 int main() {
-    gc.print_contents();
+    init();
+    gc->force_collect();
+    gc->print_contents();
+    //delete gc;
     return 0;
 }

src/GC/tests/linker.cpp

@@ -0,0 +1,30 @@
+#include <stdio.h>
+
+#include "heap.hpp"
+
+struct Obj {
+    int a;
+    int b;
+    int c;
+};
+
+int main() {
+    auto heap = GC::Heap::the2();
+
+    std::cout << "heap:\t" << heap << std::endl;
+    
+    auto obj = static_cast<Obj *>(heap->alloc(sizeof(Obj)));
+
+    std::cout << "obj: \t" << obj << std::endl;
+
+    obj->a = 3;
+    obj->b = 4;
+    obj->c = 5;
+
+    std::cout << obj->a << ", " << obj->b << ", " << obj->c << std::endl;
+
+    heap->print_contents();
+    //delete heap;
+
+    return 0;
+}