mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-24 22:32:47 +00:00
9f617d64c5
I'm about to add. This is similar to, but necessarily different than, the STL allocator class. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31285 91177308-0d34-0410-b5e6-96231b3b80d8
107 lines
3.3 KiB
C++
107 lines
3.3 KiB
C++
//===--- Allocator.cpp - Simple memory allocation abstraction -------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file was developed by Chris Lattner and is distributed under
|
|
// the University of Illinois Open Source License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the BumpPtrAllocator interface.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Support/Allocator.h"
|
|
#include <iostream>
|
|
using namespace llvm;
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// MemRegion class implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
namespace {
|
|
/// MemRegion - This is one chunk of the BumpPtrAllocator.
|
|
class MemRegion {
|
|
unsigned RegionSize;
|
|
MemRegion *Next;
|
|
char *NextPtr;
|
|
public:
|
|
void Init(unsigned size, unsigned Alignment, MemRegion *next) {
|
|
RegionSize = size;
|
|
Next = next;
|
|
NextPtr = (char*)(this+1);
|
|
|
|
// Align NextPtr.
|
|
NextPtr = (char*)((intptr_t)(NextPtr+Alignment-1) &
|
|
~(intptr_t)(Alignment-1));
|
|
}
|
|
|
|
const MemRegion *getNext() const { return Next; }
|
|
unsigned getNumBytesAllocated() const {
|
|
return NextPtr-(const char*)this;
|
|
}
|
|
|
|
/// Allocate - Allocate and return at least the specified number of bytes.
|
|
///
|
|
void *Allocate(unsigned AllocSize, unsigned Alignment, MemRegion **RegPtr) {
|
|
// Round size up to an even multiple of the alignment.
|
|
AllocSize = (AllocSize+Alignment-1) & ~(Alignment-1);
|
|
|
|
// If there is space in this region, return it.
|
|
if (unsigned(NextPtr+AllocSize-(char*)this) <= RegionSize) {
|
|
void *Result = NextPtr;
|
|
NextPtr += AllocSize;
|
|
return Result;
|
|
}
|
|
|
|
// Otherwise, we have to allocate a new chunk. Create one twice as big as
|
|
// this one.
|
|
MemRegion *NewRegion = (MemRegion *)malloc(RegionSize*2);
|
|
NewRegion->Init(RegionSize*2, Alignment, this);
|
|
|
|
// Update the current "first region" pointer to point to the new region.
|
|
*RegPtr = NewRegion;
|
|
|
|
// Try allocating from it now.
|
|
return NewRegion->Allocate(AllocSize, Alignment, RegPtr);
|
|
}
|
|
|
|
/// Deallocate - Release all memory for this region to the system.
|
|
///
|
|
void Deallocate() {
|
|
MemRegion *next = Next;
|
|
free(this);
|
|
if (next)
|
|
next->Deallocate();
|
|
}
|
|
};
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// BumpPtrAllocator class implementation
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
BumpPtrAllocator::BumpPtrAllocator() {
|
|
TheMemory = malloc(4096);
|
|
((MemRegion*)TheMemory)->Init(4096, 1, 0);
|
|
}
|
|
|
|
BumpPtrAllocator::~BumpPtrAllocator() {
|
|
((MemRegion*)TheMemory)->Deallocate();
|
|
}
|
|
|
|
void *BumpPtrAllocator::Allocate(unsigned Size, unsigned Align) {
|
|
return ((MemRegion*)TheMemory)->Allocate(Size, Align,(MemRegion**)&TheMemory);
|
|
}
|
|
|
|
void BumpPtrAllocator::PrintStats() const {
|
|
unsigned BytesUsed = 0;
|
|
unsigned NumRegions = 0;
|
|
const MemRegion *R = (MemRegion*)TheMemory;
|
|
for (; R; R = R->getNext(), ++NumRegions)
|
|
BytesUsed += R->getNumBytesAllocated();
|
|
|
|
std::cerr << "\nNumber of memory regions: " << NumRegions << "\n";
|
|
std::cerr << "Bytes allocated: " << BytesUsed << "\n";
|
|
}
|