Changes in directory llvm/lib/Support:
Allocator.cpp added (r1.1)
---
Log message:
Add a new llvm::Allocator abstraction, which will be used by a container
I'm about to add. This is similar to, but necessarily different than, the
STL allocator class.
---
Diffs of the changes: (+106 -0)
Allocator.cpp | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 106 insertions(+)
Index: llvm/lib/Support/Allocator.cpp
diff -c /dev/null llvm/lib/Support/Allocator.cpp:1.1
*** /dev/null Sun Oct 29 16:08:13 2006
--- llvm/lib/Support/Allocator.cpp Sun Oct 29 16:08:03 2006
***************
*** 0 ****
--- 1,106 ----
+ //===--- 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";
+ }
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