It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp
new file mode 100644
index 0000000..234fd41
--- /dev/null
+++ b/lib/Support/Allocator.cpp
@@ -0,0 +1,111 @@
+//===--- 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 "llvm/Support/DataTypes.h"
+#include "llvm/Support/Streams.h"
+#include <ostream>
+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) {
+ MemRegion *MRP = (MemRegion*)TheMemory;
+ void *Ptr = MRP->Allocate(Size, Align, &MRP);
+ TheMemory = MRP;
+ return Ptr;
+}
+
+void BumpPtrAllocator::PrintStats() const {
+ unsigned BytesUsed = 0;
+ unsigned NumRegions = 0;
+ const MemRegion *R = (MemRegion*)TheMemory;
+ for (; R; R = R->getNext(), ++NumRegions)
+ BytesUsed += R->getNumBytesAllocated();
+
+ cerr << "\nNumber of memory regions: " << NumRegions << "\n";
+ cerr << "Bytes allocated: " << BytesUsed << "\n";
+}