Cleaned up include guards

This commit is contained in:
Victor Olin 2023-04-07 20:40:01 +02:00
parent a34dec35c6
commit fda9e6728f
7 changed files with 840 additions and 8 deletions

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@ -7,9 +7,9 @@
extern "C" {
#endif
// #define DEBUG
// #define WRAPPER_DEBUG
#ifdef DEBUG
#ifdef WRAPPER_DEBUG
typedef struct cheap
{
void *obj;

53
src/GC/include/event.hpp Normal file
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@ -0,0 +1,53 @@
#pragma once
#include <ctime>
#include "chunk.hpp"
namespace GC
{
/**
* Types of events that can occur on the heap.
*/
enum GCEventType
{
HeapInit,
AllocStart,
CollectStart,
MarkStart,
ChunkMarked,
ChunkSwept,
ChunkFreed,
NewChunk,
ReusedChunk,
ProfilerDispose
};
/**
* Stores metadeta about an event on the heap.
*/
class GCEvent
{
private:
const GCEventType m_type;
const std::time_t m_timestamp {std::time(NULL)};
const Chunk *m_chunk {nullptr};
const size_t m_size {0};
public:
GCEvent(GCEventType type) : m_type(type) {}
GCEvent(GCEventType type, Chunk *chunk) : m_type(type), m_chunk(chunk) {}
GCEvent(GCEventType type, size_t size) : m_type(type), m_size(size) {}
~GCEvent() {
if (m_chunk != nullptr)
delete m_chunk;
}
GCEventType get_type();
std::time_t get_time_stamp();
const Chunk *get_chunk();
size_t get_size();
const char *type_to_string();
};
}

97
src/GC/include/heap.hpp Normal file
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#pragma once
#include <stdlib.h>
#include <vector>
#include "chunk.hpp"
#include "profiler.hpp"
#define HEAP_SIZE 2097152 //65536
#define FREE_THRESH (uint) 100000
// #define HEAP_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 HEAP_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
};
}

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#pragma once
#include <iostream>
#include <vector>
#include "chunk.hpp"
#include "event.hpp"
namespace GC {
class Profiler {
private:
Profiler() {}
~Profiler()
{
for (GCEvent *c : m_events)
delete c;
}
/**
* Returns the instance of the Profiler singleton.
* If m_instance is the nullptr and the profiler
* is not initialized yet, initialize it and return
* the pointer to it. Otherwise return the previously
* initialized pointer.
*
* @returns The pointer to the profiler singleton.
*/
static Profiler *the()
{
if (m_instance)
return m_instance;
m_instance = new Profiler();
return m_instance;
}
inline static Profiler *m_instance {nullptr};
std::vector<GCEvent *> m_events;
std::ofstream create_file_stream();
std::string get_log_folder();
static void dump_trace();
public:
static void record(GCEventType type);
static void record(GCEventType type, size_t size);
static void record(GCEventType type, Chunk *chunk);
static void dispose();
};
}

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@ -1,10 +1,10 @@
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include "heap.hpp"
#include "cheap.h"
#ifndef DEBUG
#ifndef WRAPPER_DEBUG
struct cheap
{
void *obj;

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@ -1,7 +1,3 @@
// #include <chrono>
// #include <iostream>
// #include <list>
#include "chunk.hpp"
#include "event.hpp"

636
src/GC/lib/heap.cpp Normal file
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#include <iostream>
#include <stdexcept>
#include <stdlib.h>
#include <vector>
#include "heap.hpp"
using std::cout, std::endl, std::vector, std::hex, std::dec;
namespace GC
{
/**
* This implementation of the() guarantees laziness
* on the instance and a correct destruction with
* the destructor.
*
* @returns The singleton object.
*/
Heap& Heap::the()
{
static Heap instance;
return instance;
}
/**
* Initialises the heap singleton and saves the address
* of the calling function's stack frame as the stack_top.
* Presumeably this address points to the stack frame of
* the compiled LLVM executable after linking.
*/
void Heap::init()
{
Heap &heap = Heap::the();
if (heap.profiler_enabled())
Profiler::record(HeapInit);
// clang complains because arg for __b_f_a is not 0 which is "unsafe"
#pragma clang diagnostic ignored "-Wframe-address"
heap.m_stack_top = static_cast<uintptr_t *>(__builtin_frame_address(1));
}
/**
* Disposes the heap and the profiler at program exit
* which also triggers a heap log file dumped if the
* profiler is enabled.
*/
void Heap::dispose()
{
Heap &heap = Heap::the();
if (heap.profiler_enabled())
Profiler::dispose();
}
/**
* Allocates a given amount of bytes on the heap.
*
* @param size The amount of bytes to be allocated.
*
* @return A pointer to the address where the memory
* has been allocated. This pointer is supposed
* to be casted to and object pointer.
*/
void *Heap::alloc(size_t size)
{
// Singleton
Heap &heap = Heap::the();
bool profiler_enabled = heap.profiler_enabled();
if (profiler_enabled)
Profiler::record(AllocStart, size);
if (size == 0)
{
cout << "Heap: Cannot alloc 0B. No bytes allocated." << endl;
return nullptr;
}
if (heap.m_size + size > HEAP_SIZE)
{
heap.collect();
// If memory is not enough after collect, crash with OOM error
if (heap.m_size + size > HEAP_SIZE)
throw std::runtime_error(std::string("Error: Heap out of memory"));
}
// If a chunk was recycled, return the old chunk address
Chunk *reused_chunk = heap.try_recycle_chunks(size);
if (reused_chunk != nullptr)
{
if (profiler_enabled)
Profiler::record(ReusedChunk, reused_chunk);
return static_cast<void *>(reused_chunk->m_start);
}
// If no free chunks was found (reused_chunk is a nullptr),
// then create a new chunk
auto new_chunk = new Chunk(size, (uintptr_t *)(heap.m_heap + heap.m_size));
heap.m_size += size;
heap.m_allocated_chunks.push_back(new_chunk);
if (profiler_enabled)
Profiler::record(NewChunk, new_chunk);
return new_chunk->m_start;
}
/**
* Tries to recycle used and freed chunks that are
* already allocated objects by the OS but freed
* from our Heap. This reduces the amount of GC
* objects slightly which saves time from malloc'ing
* memory from the OS.
*
* @param size Amount of bytes needed for the object
* which is about to be allocated.
*
* @returns If a chunk is found and recycled, a
* pointer to the allocated memory for
* the object is returned. If not, a
* nullptr is returned to signify no
* chunks were found.
*/
Chunk *Heap::try_recycle_chunks(size_t size)
{
Heap &heap = Heap::the();
// Check if there are any freed chunks large enough for current request
for (size_t i = 0; i < heap.m_freed_chunks.size(); i++)
{
//auto chunk = Heap::get_at(heap.m_freed_chunks, i);
auto chunk = heap.m_freed_chunks[i];
auto iter = heap.m_freed_chunks.begin();
advance(iter, i);
if (chunk->m_size > size)
{
// Split the chunk, use one part and add the remaining part to
// the list of freed chunks
size_t diff = chunk->m_size - size;
auto chunk_complement = new Chunk(diff, chunk->m_start + chunk->m_size);
heap.m_freed_chunks.erase(iter);
heap.m_freed_chunks.push_back(chunk_complement);
heap.m_allocated_chunks.push_back(chunk);
return chunk;
}
else if (chunk->m_size == size)
{
// Reuse the whole chunk
heap.m_freed_chunks.erase(iter);
heap.m_allocated_chunks.push_back(chunk);
return chunk;
}
}
// If no chunk was found, return nullptr
return nullptr;
}
/**
* Returns a bool whether the profiler is enabled
* or not.
*
* @returns True or false if the profiler is enabled
* or disabled respectively.
*/
bool Heap::profiler_enabled() {
Heap &heap = Heap::the();
return heap.m_profiler_enable;
}
/**
* Collection phase of the garbage collector. When
* an allocation is requested and there is no space
* left on the heap, a collection is triggered. This
* function is private so that the user cannot trigger
* a collection unneccessarily.
*/
void Heap::collect()
{
Heap &heap = Heap::the();
if (heap.profiler_enabled())
Profiler::record(CollectStart);
// get current stack frame
auto stack_bottom = reinterpret_cast<uintptr_t *>(__builtin_frame_address(0));
if (heap.m_stack_top == nullptr)
throw std::runtime_error(std::string("Error: Heap is not initialized, read the docs!"));
uintptr_t *stack_top = heap.m_stack_top;
auto work_list = heap.m_allocated_chunks;
mark(stack_bottom, stack_top, work_list);
sweep(heap);
free(heap);
}
/**
* Iterates through the stack, if an element on the stack points to a chunk,
* called a root chunk, that chunk is marked (i.e. reachable).
* Then it recursively follows all chunks which are possibly reachable from
* the root chunk and mark those chunks.
* If a chunk is marked it is removed from the worklist, since it's no longer of
* concern for this method.
*
* Time complexity: 0(N^2 * log(N)) as upper bound.
* Where N is either the size of the worklist or the size of
* the stack frame, depending on which is the largest.
*
* @param start Pointer to the start of the stack frame.
* @param end Pointer to the end of the stack frame.
* @param worklist The currently allocated chunks, which haven't been marked.
*/
void Heap::mark(uintptr_t *start, const uintptr_t* const end, vector<Chunk *> &worklist)
{
Heap &heap = Heap::the();
bool profiler_enabled = heap.m_profiler_enable;
if (profiler_enabled)
Profiler::record(MarkStart);
// To find adresses thats in the worklist
for (; start <= end; start++)
{
auto it = worklist.begin();
auto stop = worklist.end();
while (it != stop)
{
Chunk *chunk = *it;
auto c_start = reinterpret_cast<uintptr_t>(chunk->m_start);
auto c_size = reinterpret_cast<uintptr_t>(chunk->m_size);
auto c_end = reinterpret_cast<uintptr_t>(c_start + c_size);
// Check if the stack pointer points to something within the chunk
if (c_start <= *start && *start < c_end)
{
if (!chunk->m_marked)
{
if (profiler_enabled)
Profiler::record(ChunkMarked, chunk);
chunk->m_marked = true;
it = worklist.erase(it);
// Recursively call mark, to see if the reachable chunk further points to another chunk
mark((uintptr_t *)c_start, (uintptr_t *)c_end, worklist);
}
else
{
++it;
}
}
else
{
++it;
}
}
}
}
/**
* Sweeps the heap, unmarks the marked chunks for the next cycle,
* adds the unmarked nodes to the list of freed chunks; to be freed.
*
* Time complexity: O(N^2), where N is the number of allocated chunks.
* It is quadratic, in the worst case,
* since each call to erase() is linear.
*
* @param heap Pointer to the heap singleton instance.
*/
void Heap::sweep(Heap &heap)
{
auto iter = heap.m_allocated_chunks.begin();
bool profiler_enabled = heap.m_profiler_enable;
// This cannot "iter != stop", results in seg fault, since the end gets updated, I think.
while (iter != heap.m_allocated_chunks.end())
{
Chunk *chunk = *iter;
// Unmark the marked chunks for the next iteration.
if (chunk->m_marked)
{
chunk->m_marked = false;
++iter;
}
else
{
// Add the unmarked chunks to freed chunks and remove from
// the list of allocated chunks
if (profiler_enabled)
Profiler::record(ChunkSwept, chunk);
heap.m_freed_chunks.push_back(chunk);
iter = heap.m_allocated_chunks.erase(iter);
}
}
}
/**
* Frees chunks that was moved to the list m_freed_chunks
* by the sweep phase. If there are more than a certain
* amount of free chunks, delete the free chunks to
* avoid cluttering.
*
* Time complexity: O(N^2), where N is the freed chunks.
* If free_overlap() is called, it runs in O(N^2),
* otherwise O(N).
*
* @param heap Heap singleton instance, only for avoiding
* redundant calls to the singleton get
*/
void Heap::free(Heap &heap)
{
if (heap.m_freed_chunks.size() > FREE_THRESH)
{
bool profiler_enabled = heap.profiler_enabled();
while (heap.m_freed_chunks.size())
{
auto chunk = heap.m_freed_chunks.back();
heap.m_freed_chunks.pop_back();
if (profiler_enabled)
Profiler::record(ChunkFreed, chunk);
delete chunk;
}
}
// if there are chunks but not more than FREE_THRESH
else if (heap.m_freed_chunks.size())
{
// essentially, always check for overlap between
// chunks before finishing the allocation
free_overlap(heap);
}
}
/**
* Checks for overlaps between freed chunks of memory
* and removes overlapping chunks while prioritizing
* the chunks at lower addresses.
*
* Time complexity: O(N^2), where N is the number of freed chunks.
* At each iteration get_at() is called, which is linear.
*
* @param heap Heap singleton instance, only for avoiding
* redundant calls to the singleton get
*
* @note Maybe this should be changed to prioritizing
* larger chunks. Should remove get_at() to indexing,
* since that's constant.
*/
void Heap::free_overlap(Heap &heap) // borde göra en record(ChunkFreed) på onödiga chunks
{
std::vector<Chunk *> filtered;
size_t i = 0;
//auto prev = Heap::get_at(heap.m_freed_chunks, i++);
auto prev = heap.m_freed_chunks[i++];
prev->m_marked = true;
filtered.push_back(prev);
cout << filtered.back()->m_start << endl;
for (; i < heap.m_freed_chunks.size(); i++)
{
prev = filtered.back();
//auto next = Heap::get_at(heap.m_freed_chunks, i);
auto next = heap.m_freed_chunks[i];
auto p_start = (uintptr_t)(prev->m_start);
auto p_size = (uintptr_t)(prev->m_size);
auto n_start = (uintptr_t)(next->m_start);
if (n_start >= (p_start + p_size))
{
next->m_marked = true;
filtered.push_back(next);
}
}
heap.m_freed_chunks.swap(filtered);
bool profiler_enabled = heap.m_profiler_enable;
// After swap m_freed_chunks contains still available chunks
// and filtered contains all the chunks, so delete unused chunks
for (Chunk *chunk : filtered)
{
// if chunk was filtered away, delete it
if (!chunk->m_marked)
{
if (profiler_enabled)
Profiler::record(ChunkFreed, chunk);
delete chunk;
}
else
{
chunk->m_marked = false;
}
}
}
void Heap::set_profiler(bool mode)
{
Heap &heap = Heap::the();
heap.m_profiler_enable = mode;
}
#ifdef HEAP_DEBUG
/**
* Prints the result of Heap::init() and a dummy value
* for the current stack frame for reference.
*/
void Heap::check_init()
{
Heap &heap = Heap::the();
cout << "Heap addr:\t" << &heap << "\n";
cout << "GC m_stack_top:\t" << heap.m_stack_top << "\n";
auto stack_bottom = reinterpret_cast<uintptr_t *>(__builtin_frame_address(0));
cout << "GC stack_bottom:\t" << stack_bottom << endl;
}
/**
* Conditional collection, only to be used in debugging
*
* @param flags Bitmap of flags
*/
void Heap::collect(CollectOption flags)
{
set_profiler(true);
Heap &heap = Heap::the();
if (heap.m_profiler_enable)
Profiler::record(CollectStart);
cout << "DEBUG COLLECT\nFLAGS: ";
if (flags & MARK)
cout << "\n - MARK";
if (flags & SWEEP)
cout << "\n - SWEEP";
if (flags & FREE)
cout << "\n - FREE";
cout << "\n";
// get the frame adress, whwere local variables and saved registers are located
auto stack_bottom = reinterpret_cast<uintptr_t *>(__builtin_frame_address(0));
cout << "Stack bottom in collect:\t" << stack_bottom << "\n";
uintptr_t *stack_top = heap.m_stack_top;
cout << "Stack end in collect:\t " << stack_top << endl;
auto work_list = heap.m_allocated_chunks;
if (flags & MARK)
mark(stack_bottom, stack_top, work_list);
if (flags & SWEEP)
sweep(heap);
if (flags & FREE)
free(heap);
}
// Mark child references from the root references
void mark_test(vector<Chunk *> &worklist)
{
while (worklist.size() > 0)
{
Chunk *ref = worklist.back();
worklist.pop_back();
Chunk *child = (Chunk *)ref; // this is probably not correct
if (child != nullptr && !child->m_marked)
{
child->m_marked = true;
worklist.push_back(child);
mark_test(worklist);
}
}
}
// Mark the root references and look for child references to them
void mark_from_roots(uintptr_t *start, const uintptr_t *end)
{
vector<Chunk *> worklist;
for (; start > end; start--)
{
if (*start % 8 == 0)
{ // all pointers must be aligned as double words
Chunk *ref = (Chunk *)*start;
if (ref != nullptr && !ref->m_marked)
{
ref->m_marked = true;
worklist.push_back(ref);
mark_test(worklist);
}
}
}
}
// For testing purposes
void Heap::print_line(Chunk *chunk)
{
cout << "Marked: " << chunk->m_marked << "\nStart adr: " << chunk->m_start << "\nSize: " << chunk->m_size << " B\n"
<< endl;
}
void Heap::print_worklist(std::vector<Chunk *> &list)
{
for (auto cp : list)
cout << "Chunk at:\t" << cp->m_start << "\nSize:\t\t" << cp->m_size << "\n";
cout << endl;
}
void Heap::print_contents()
{
Heap &heap = Heap::the();
if (heap.m_allocated_chunks.size())
{
cout << "\nALLOCATED CHUNKS #" << dec << heap.m_allocated_chunks.size() << endl;
for (auto chunk : heap.m_allocated_chunks)
print_line(chunk);
}
else
{
cout << "NO ALLOCATIONS\n" << endl;
}
if (heap.m_freed_chunks.size())
{
cout << "\nFREED CHUNKS #" << dec << heap.m_freed_chunks.size() << endl;
for (auto fchunk : heap.m_freed_chunks)
print_line(fchunk);
}
else
{
cout << "NO FREED CHUNKS" << endl;
}
}
void Heap::print_summary()
{
Heap &heap = Heap::the();
if (heap.m_allocated_chunks.size())
{
cout << "\nALLOCATED CHUNKS #" << dec << heap.m_allocated_chunks.size() << endl;
}
else
{
cout << "NO ALLOCATIONS\n" << endl;
}
if (heap.m_freed_chunks.size())
{
cout << "\nFREED CHUNKS #" << dec << heap.m_freed_chunks.size() << endl;
}
else
{
cout << "NO FREED CHUNKS" << endl;
}
}
void Heap::print_allocated_chunks(Heap *heap) {
cout << "--- Allocated Chunks ---\n" << endl;
for (auto chunk : heap->m_allocated_chunks) {
print_line(chunk);
}
}
Chunk *Heap::try_recycle_chunks_new(size_t size)
{
Heap &heap = Heap::the();
// Check if there are any freed chunks large enough for current request
for (size_t i = 0; i < heap.m_freed_chunks.size(); i++)
{
auto chunk = heap.m_freed_chunks[i]; //Heap::get_at(heap.m_freed_chunks, i);
auto iter = heap.m_freed_chunks.begin();
//advance(iter, i);
i++;
if (chunk->m_size > size)
{
// Split the chunk, use one part and add the remaining part to
// the list of freed chunks
size_t diff = chunk->m_size - size;
auto chunk_complement = new Chunk(diff, chunk->m_start + chunk->m_size);
heap.m_freed_chunks.erase(iter);
heap.m_freed_chunks.push_back(chunk_complement);
heap.m_allocated_chunks.push_back(chunk);
return chunk;
}
else if (chunk->m_size == size)
{
// Reuse the whole chunk
heap.m_freed_chunks.erase(iter);
heap.m_allocated_chunks.push_back(chunk);
return chunk;
}
}
// If no chunk was found, return nullptr
return nullptr;
}
void Heap::free_overlap_new(Heap &heap) // borde göra en record(ChunkFreed) på onödiga chunks
{
std::vector<Chunk *> filtered;
size_t i = 0;
auto prev = heap.m_freed_chunks[i++]; //Heap::get_at(heap.m_freed_chunks, i++);
prev->m_marked = true;
filtered.push_back(prev);
cout << filtered.back()->m_start << endl;
for (; i < heap.m_freed_chunks.size(); i++)
{
prev = filtered.back();
auto next = heap.m_freed_chunks[i]; //Heap::get_at(heap.m_freed_chunks, i);
auto p_start = (uintptr_t)(prev->m_start);
auto p_size = (uintptr_t)(prev->m_size);
auto n_start = (uintptr_t)(next->m_start);
if (n_start >= (p_start + p_size))
{
next->m_marked = true;
filtered.push_back(next);
}
}
heap.m_freed_chunks.swap(filtered);
bool profiler_enabled = heap.m_profiler_enable;
// After swap m_freed_chunks contains still available chunks
// and filtered contains all the chunks, so delete unused chunks
for (Chunk *chunk : filtered)
{
// if chunk was filtered away, delete it
if (!chunk->m_marked)
{
if (profiler_enabled)
Profiler::record(ChunkFreed, chunk);
delete chunk;
}
else
{
chunk->m_marked = false;
}
}
}
#endif
}