Let BumpPtrAllocator lazily allocate the first slab.
We have some code in llvm and clang where a BumpPtrAllocator is declared in a
class but never used in the common case. Stop wasting memory there.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@101130 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp
index 31b45c8..ef40e47 100644
--- a/lib/Support/Allocator.cpp
+++ b/lib/Support/Allocator.cpp
@@ -23,9 +23,7 @@
BumpPtrAllocator::BumpPtrAllocator(size_t size, size_t threshold,
SlabAllocator &allocator)
: SlabSize(size), SizeThreshold(threshold), Allocator(allocator),
- CurSlab(0), BytesAllocated(0) {
- StartNewSlab();
-}
+ CurSlab(0), BytesAllocated(0) { }
BumpPtrAllocator::~BumpPtrAllocator() {
DeallocateSlabs(CurSlab);
@@ -72,6 +70,8 @@
/// Reset - Deallocate all but the current slab and reset the current pointer
/// to the beginning of it, freeing all memory allocated so far.
void BumpPtrAllocator::Reset() {
+ if (!CurSlab) // Start a new slab if we didn't allocate one already.
+ StartNewSlab();
DeallocateSlabs(CurSlab->NextPtr);
CurSlab->NextPtr = 0;
CurPtr = (char*)(CurSlab + 1);
@@ -81,6 +81,9 @@
/// Allocate - Allocate space at the specified alignment.
///
void *BumpPtrAllocator::Allocate(size_t Size, size_t Alignment) {
+ if (!CurSlab) // Start a new slab if we haven't allocated one already.
+ StartNewSlab();
+
// Keep track of how many bytes we've allocated.
BytesAllocated += Size;