// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
-//
-// This file defines the MallocAllocator and BumpPtrAllocator interfaces.
-//
+/// \file
+///
+/// This file defines the MallocAllocator and BumpPtrAllocator interfaces. Both
+/// of these conform to an LLVM "Allocator" concept which consists of an
+/// Allocate method accepting a size and alignment, and a Deallocate accepting
+/// a pointer and size. Further, the LLVM "Allocator" concept has overloads of
+/// Allocate and Deallocate for setting size and alignment based on the final
+/// type. These overloads are typically provided by a base class template \c
+/// AllocatorBase.
+///
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_ALLOCATOR_H
#include <cstdlib>
namespace llvm {
-template <typename T> struct ReferenceAdder {
- typedef T &result;
-};
-template <typename T> struct ReferenceAdder<T &> {
- typedef T result;
-};
-class MallocAllocator {
+/// \brief CRTP base class providing obvious overloads for the core \c
+/// Allocate() methods of LLVM-style allocators.
+///
+/// This base class both documents the full public interface exposed by all
+/// LLVM-style allocators, and redirects all of the overloads to a single core
+/// set of methods which the derived class must define.
+template <typename DerivedT> class AllocatorBase {
public:
- MallocAllocator() {}
- ~MallocAllocator() {}
+ /// \brief Allocate \a Size bytes of \a Alignment aligned memory. This method
+ /// must be implemented by \c DerivedT.
+ void *Allocate(size_t Size, size_t Alignment) {
+#ifdef __clang__
+ static_assert(static_cast<void *(AllocatorBase::*)(size_t, size_t)>(
+ &AllocatorBase::Allocate) !=
+ static_cast<void *(DerivedT::*)(size_t, size_t)>(
+ &DerivedT::Allocate),
+ "Class derives from AllocatorBase without implementing the "
+ "core Allocate(size_t, size_t) overload!");
+#endif
+ return static_cast<DerivedT *>(this)->Allocate(Size, Alignment);
+ }
- void Reset() {}
+ /// \brief Deallocate \a Ptr to \a Size bytes of memory allocated by this
+ /// allocator.
+ void Deallocate(const void *Ptr, size_t Size) {
+#ifdef __clang__
+ static_assert(static_cast<void (AllocatorBase::*)(const void *, size_t)>(
+ &AllocatorBase::Deallocate) !=
+ static_cast<void (DerivedT::*)(const void *, size_t)>(
+ &DerivedT::Deallocate),
+ "Class derives from AllocatorBase without implementing the "
+ "core Deallocate(void *) overload!");
+#endif
+ return static_cast<DerivedT *>(this)->Deallocate(Ptr, Size);
+ }
- void *Allocate(size_t Size, size_t /*Alignment*/) { return malloc(Size); }
+ // The rest of these methods are helpers that redirect to one of the above
+ // core methods.
- template <typename T> T *Allocate() {
- return static_cast<T *>(malloc(sizeof(T)));
+ /// \brief Allocate space for a sequence of objects without constructing them.
+ template <typename T> T *Allocate(size_t Num = 1) {
+ return static_cast<T *>(Allocate(Num * sizeof(T), AlignOf<T>::Alignment));
}
- template <typename T> T *Allocate(size_t Num) {
- return static_cast<T *>(malloc(sizeof(T) * Num));
+ /// \brief Deallocate space for a sequence of objects without constructing them.
+ template <typename T>
+ typename std::enable_if<
+ !std::is_same<typename std::remove_cv<T>::type, void>::value, void>::type
+ Deallocate(T *Ptr, size_t Num = 1) {
+ Deallocate(static_cast<const void *>(Ptr), Num * sizeof(T));
}
-
- void Deallocate(const void *Ptr) { free(const_cast<void *>(Ptr)); }
-
- void PrintStats() const {}
};
-/// SlabAllocator - This class can be used to parameterize the underlying
-/// allocation strategy for the bump allocator. In particular, this is used
-/// by the JIT to allocate contiguous swathes of executable memory. The
-/// interface uses MemSlab's instead of void *'s so that the allocator
-/// doesn't have to remember the size of the pointer it allocated.
-class SlabAllocator {
+class MallocAllocator : public AllocatorBase<MallocAllocator> {
public:
- virtual ~SlabAllocator();
- virtual void *Allocate(size_t Size) = 0;
- virtual void Deallocate(void *Slab, size_t Size) = 0;
-};
+ void Reset() {}
-/// MallocSlabAllocator - The default slab allocator for the bump allocator
-/// is an adapter class for MallocAllocator that just forwards the method
-/// calls and translates the arguments.
-class MallocSlabAllocator : public SlabAllocator {
- /// Allocator - The underlying allocator that we forward to.
- ///
- MallocAllocator Allocator;
+ LLVM_ATTRIBUTE_RETURNS_NONNULL void *Allocate(size_t Size,
+ size_t /*Alignment*/) {
+ return malloc(Size);
+ }
-public:
- MallocSlabAllocator() : Allocator() {}
- virtual ~MallocSlabAllocator();
- void *Allocate(size_t Size) override;
- void Deallocate(void *Slab, size_t Size) override;
+ // Pull in base class overloads.
+ using AllocatorBase<MallocAllocator>::Allocate;
+
+ void Deallocate(const void *Ptr, size_t /*Size*/) {
+ free(const_cast<void *>(Ptr));
+ }
+
+ // Pull in base class overloads.
+ using AllocatorBase<MallocAllocator>::Deallocate;
+
+ void PrintStats() const {}
};
+namespace detail {
+
+// We call out to an external function to actually print the message as the
+// printing code uses Allocator.h in its implementation.
+void printBumpPtrAllocatorStats(unsigned NumSlabs, size_t BytesAllocated,
+ size_t TotalMemory);
+} // End namespace detail.
+
/// \brief Allocate memory in an ever growing pool, as if by bump-pointer.
///
/// This isn't strictly a bump-pointer allocator as it uses backing slabs of
-/// memory rather than relying on boundless contiguous heap. However, it has
-/// bump-pointer semantics in that is a monotonically growing pool of memory
+/// memory rather than relying on a boundless contiguous heap. However, it has
+/// bump-pointer semantics in that it is a monotonically growing pool of memory
/// where every allocation is found by merely allocating the next N bytes in
/// the slab, or the next N bytes in the next slab.
///
/// Note that this also has a threshold for forcing allocations above a certain
/// size into their own slab.
-template <size_t SlabSize = 4096, size_t SizeThreshold = SlabSize>
-class BumpPtrAllocatorImpl {
- BumpPtrAllocatorImpl(const BumpPtrAllocatorImpl &) LLVM_DELETED_FUNCTION;
- void operator=(const BumpPtrAllocatorImpl &) LLVM_DELETED_FUNCTION;
-
+///
+/// The BumpPtrAllocatorImpl template defaults to using a MallocAllocator
+/// object, which wraps malloc, to allocate memory, but it can be changed to
+/// use a custom allocator.
+template <typename AllocatorT = MallocAllocator, size_t SlabSize = 4096,
+ size_t SizeThreshold = SlabSize>
+class BumpPtrAllocatorImpl
+ : public AllocatorBase<
+ BumpPtrAllocatorImpl<AllocatorT, SlabSize, SizeThreshold>> {
public:
static_assert(SizeThreshold <= SlabSize,
"The SizeThreshold must be at most the SlabSize to ensure "
"allocation.");
BumpPtrAllocatorImpl()
+ : CurPtr(nullptr), End(nullptr), BytesAllocated(0), Allocator() {}
+ template <typename T>
+ BumpPtrAllocatorImpl(T &&Allocator)
: CurPtr(nullptr), End(nullptr), BytesAllocated(0),
- Allocator(DefaultSlabAllocator) {}
- BumpPtrAllocatorImpl(SlabAllocator &Allocator)
- : CurPtr(nullptr), End(nullptr), BytesAllocated(0), Allocator(Allocator) {
+ Allocator(std::forward<T &&>(Allocator)) {}
+
+ // Manually implement a move constructor as we must clear the old allocator's
+ // slabs as a matter of correctness.
+ BumpPtrAllocatorImpl(BumpPtrAllocatorImpl &&Old)
+ : CurPtr(Old.CurPtr), End(Old.End), Slabs(std::move(Old.Slabs)),
+ CustomSizedSlabs(std::move(Old.CustomSizedSlabs)),
+ BytesAllocated(Old.BytesAllocated),
+ Allocator(std::move(Old.Allocator)) {
+ Old.CurPtr = Old.End = nullptr;
+ Old.BytesAllocated = 0;
+ Old.Slabs.clear();
+ Old.CustomSizedSlabs.clear();
}
+
~BumpPtrAllocatorImpl() {
DeallocateSlabs(Slabs.begin(), Slabs.end());
DeallocateCustomSizedSlabs();
}
+ BumpPtrAllocatorImpl &operator=(BumpPtrAllocatorImpl &&RHS) {
+ DeallocateSlabs(Slabs.begin(), Slabs.end());
+ DeallocateCustomSizedSlabs();
+
+ CurPtr = RHS.CurPtr;
+ End = RHS.End;
+ BytesAllocated = RHS.BytesAllocated;
+ Slabs = std::move(RHS.Slabs);
+ CustomSizedSlabs = std::move(RHS.CustomSizedSlabs);
+ Allocator = std::move(RHS.Allocator);
+
+ RHS.CurPtr = RHS.End = nullptr;
+ RHS.BytesAllocated = 0;
+ RHS.Slabs.clear();
+ RHS.CustomSizedSlabs.clear();
+ return *this;
+ }
+
/// \brief Deallocate all but the current slab and reset the current pointer
/// to the beginning of it, freeing all memory allocated so far.
void Reset() {
+ DeallocateCustomSizedSlabs();
+ CustomSizedSlabs.clear();
+
if (Slabs.empty())
return;
CurPtr = (char *)Slabs.front();
End = CurPtr + SlabSize;
- // Deallocate all but the first slab, and all custome sized slabs.
+ // Deallocate all but the first slab, and deallocate all custom-sized slabs.
DeallocateSlabs(std::next(Slabs.begin()), Slabs.end());
Slabs.erase(std::next(Slabs.begin()), Slabs.end());
- DeallocateCustomSizedSlabs();
- CustomSizedSlabs.clear();
}
/// \brief Allocate space at the specified alignment.
- void *Allocate(size_t Size, size_t Alignment) {
- if (!CurPtr) // Start a new slab if we haven't allocated one already.
- StartNewSlab();
+ LLVM_ATTRIBUTE_RETURNS_NONNULL LLVM_ATTRIBUTE_RETURNS_NOALIAS void *
+ Allocate(size_t Size, size_t Alignment) {
+ assert(Alignment > 0 && "0-byte alignnment is not allowed. Use 1 instead.");
// Keep track of how many bytes we've allocated.
BytesAllocated += Size;
- // 0-byte alignment means 1-byte alignment.
- if (Alignment == 0)
- Alignment = 1;
+ size_t Adjustment = alignmentAdjustment(CurPtr, Alignment);
+ assert(Adjustment + Size >= Size && "Adjustment + Size must not overflow");
- // Allocate the aligned space, going forwards from CurPtr.
- char *Ptr = alignPtr(CurPtr, Alignment);
-
- // Check if we can hold it.
- if (Ptr + Size <= End) {
- CurPtr = Ptr + Size;
+ // Check if we have enough space.
+ if (Adjustment + Size <= size_t(End - CurPtr)) {
+ char *AlignedPtr = CurPtr + Adjustment;
+ CurPtr = AlignedPtr + Size;
// Update the allocation point of this memory block in MemorySanitizer.
// Without this, MemorySanitizer messages for values originated from here
// will point to the allocation of the entire slab.
- __msan_allocated_memory(Ptr, Size);
- return Ptr;
+ __msan_allocated_memory(AlignedPtr, Size);
+ return AlignedPtr;
}
// If Size is really big, allocate a separate slab for it.
size_t PaddedSize = Size + Alignment - 1;
if (PaddedSize > SizeThreshold) {
- void *NewSlab = Allocator.Allocate(PaddedSize);
+ void *NewSlab = Allocator.Allocate(PaddedSize, 0);
CustomSizedSlabs.push_back(std::make_pair(NewSlab, PaddedSize));
- Ptr = alignPtr((char *)NewSlab, Alignment);
- assert((uintptr_t)Ptr + Size <= (uintptr_t)NewSlab + PaddedSize);
- __msan_allocated_memory(Ptr, Size);
- return Ptr;
+ uintptr_t AlignedAddr = alignAddr(NewSlab, Alignment);
+ assert(AlignedAddr + Size <= (uintptr_t)NewSlab + PaddedSize);
+ char *AlignedPtr = (char*)AlignedAddr;
+ __msan_allocated_memory(AlignedPtr, Size);
+ return AlignedPtr;
}
// Otherwise, start a new slab and try again.
StartNewSlab();
- Ptr = alignPtr(CurPtr, Alignment);
- CurPtr = Ptr + Size;
- assert(CurPtr <= End && "Unable to allocate memory!");
- __msan_allocated_memory(Ptr, Size);
- return Ptr;
- }
-
- /// \brief Allocate space for one object without constructing it.
- template <typename T> T *Allocate() {
- return static_cast<T *>(Allocate(sizeof(T), AlignOf<T>::Alignment));
+ uintptr_t AlignedAddr = alignAddr(CurPtr, Alignment);
+ assert(AlignedAddr + Size <= (uintptr_t)End &&
+ "Unable to allocate memory!");
+ char *AlignedPtr = (char*)AlignedAddr;
+ CurPtr = AlignedPtr + Size;
+ __msan_allocated_memory(AlignedPtr, Size);
+ return AlignedPtr;
}
- /// \brief Allocate space for an array of objects without constructing them.
- template <typename T> T *Allocate(size_t Num) {
- return static_cast<T *>(Allocate(Num * sizeof(T), AlignOf<T>::Alignment));
- }
+ // Pull in base class overloads.
+ using AllocatorBase<BumpPtrAllocatorImpl>::Allocate;
- /// \brief Allocate space for an array of objects with the specified alignment
- /// and without constructing them.
- template <typename T> T *Allocate(size_t Num, size_t Alignment) {
- // Round EltSize up to the specified alignment.
- size_t EltSize = (sizeof(T) + Alignment - 1) & (-Alignment);
- return static_cast<T *>(Allocate(Num * EltSize, Alignment));
- }
+ void Deallocate(const void * /*Ptr*/, size_t /*Size*/) {}
- void Deallocate(const void * /*Ptr*/) {}
+ // Pull in base class overloads.
+ using AllocatorBase<BumpPtrAllocatorImpl>::Deallocate;
size_t GetNumSlabs() const { return Slabs.size() + CustomSizedSlabs.size(); }
}
void PrintStats() const {
- // We call out to an external function to actually print the message as the
- // printing code uses Allocator.h in its implementation.
- extern void printBumpPtrAllocatorStats(
- unsigned NumSlabs, size_t BytesAllocated, size_t TotalMemory);
-
- printBumpPtrAllocatorStats(Slabs.size(), BytesAllocated, getTotalMemory());
+ detail::printBumpPtrAllocatorStats(Slabs.size(), BytesAllocated,
+ getTotalMemory());
}
private:
/// Used so that we can compute how much space was wasted.
size_t BytesAllocated;
- /// \brief The default allocator used if one is not provided.
- MallocSlabAllocator DefaultSlabAllocator;
-
- /// \brief The underlying allocator we use to get slabs of memory.
- ///
- /// This defaults to MallocSlabAllocator, which wraps malloc, but it could be
- /// changed to use a custom allocator.
- SlabAllocator &Allocator;
+ /// \brief The allocator instance we use to get slabs of memory.
+ AllocatorT Allocator;
static size_t computeSlabSize(unsigned SlabIdx) {
// Scale the actual allocated slab size based on the number of slabs
void StartNewSlab() {
size_t AllocatedSlabSize = computeSlabSize(Slabs.size());
- void *NewSlab = Allocator.Allocate(AllocatedSlabSize);
+ void *NewSlab = Allocator.Allocate(AllocatedSlabSize, 0);
Slabs.push_back(NewSlab);
CurPtr = (char *)(NewSlab);
End = ((char *)NewSlab) + AllocatedSlabSize;
for (; I != E; ++I) {
size_t AllocatedSlabSize =
computeSlabSize(std::distance(Slabs.begin(), I));
-#ifndef NDEBUG
- // Poison the memory so stale pointers crash sooner. Note we must
- // preserve the Size and NextPtr fields at the beginning.
- sys::Memory::setRangeWritable(*I, AllocatedSlabSize);
- memset(*I, 0xCD, AllocatedSlabSize);
-#endif
Allocator.Deallocate(*I, AllocatedSlabSize);
}
}
for (auto &PtrAndSize : CustomSizedSlabs) {
void *Ptr = PtrAndSize.first;
size_t Size = PtrAndSize.second;
-#ifndef NDEBUG
- // Poison the memory so stale pointers crash sooner. Note we must
- // preserve the Size and NextPtr fields at the beginning.
- sys::Memory::setRangeWritable(Ptr, Size);
- memset(Ptr, 0xCD, Size);
-#endif
Allocator.Deallocate(Ptr, Size);
}
}
public:
SpecificBumpPtrAllocator() : Allocator() {}
- SpecificBumpPtrAllocator(SlabAllocator &allocator) : Allocator(allocator) {}
-
+ SpecificBumpPtrAllocator(SpecificBumpPtrAllocator &&Old)
+ : Allocator(std::move(Old.Allocator)) {}
~SpecificBumpPtrAllocator() { DestroyAll(); }
+ SpecificBumpPtrAllocator &operator=(SpecificBumpPtrAllocator &&RHS) {
+ Allocator = std::move(RHS.Allocator);
+ return *this;
+ }
+
/// Call the destructor of each allocated object and deallocate all but the
/// current slab and reset the current pointer to the beginning of it, freeing
/// all memory allocated so far.
void DestroyAll() {
auto DestroyElements = [](char *Begin, char *End) {
- assert(Begin == alignPtr(Begin, alignOf<T>()));
+ assert(Begin == (char*)alignAddr(Begin, alignOf<T>()));
for (char *Ptr = Begin; Ptr + sizeof(T) <= End; Ptr += sizeof(T))
reinterpret_cast<T *>(Ptr)->~T();
};
++I) {
size_t AllocatedSlabSize = BumpPtrAllocator::computeSlabSize(
std::distance(Allocator.Slabs.begin(), I));
- char *Begin = alignPtr((char *)*I, alignOf<T>());
+ char *Begin = (char*)alignAddr(*I, alignOf<T>());
char *End = *I == Allocator.Slabs.back() ? Allocator.CurPtr
: (char *)*I + AllocatedSlabSize;
for (auto &PtrAndSize : Allocator.CustomSizedSlabs) {
void *Ptr = PtrAndSize.first;
size_t Size = PtrAndSize.second;
- DestroyElements(alignPtr((char *)Ptr, alignOf<T>()), (char *)Ptr + Size);
+ DestroyElements((char*)alignAddr(Ptr, alignOf<T>()), (char *)Ptr + Size);
}
Allocator.Reset();
/// \brief Allocate space for an array of objects without constructing them.
T *Allocate(size_t num = 1) { return Allocator.Allocate<T>(num); }
-
-private:
};
} // end namespace llvm
-template <size_t SlabSize, size_t SizeThreshold>
-void *
-operator new(size_t Size,
- llvm::BumpPtrAllocatorImpl<SlabSize, SizeThreshold> &Allocator) {
+template <typename AllocatorT, size_t SlabSize, size_t SizeThreshold>
+void *operator new(size_t Size,
+ llvm::BumpPtrAllocatorImpl<AllocatorT, SlabSize,
+ SizeThreshold> &Allocator) {
struct S {
char c;
union {
Size, std::min((size_t)llvm::NextPowerOf2(Size), offsetof(S, x)));
}
-template <size_t SlabSize, size_t SizeThreshold>
-void operator delete(void *,
- llvm::BumpPtrAllocatorImpl<SlabSize, SizeThreshold> &) {}
+template <typename AllocatorT, size_t SlabSize, size_t SizeThreshold>
+void operator delete(
+ void *, llvm::BumpPtrAllocatorImpl<AllocatorT, SlabSize, SizeThreshold> &) {
+}
#endif // LLVM_SUPPORT_ALLOCATOR_H