Import new standalone pool manager.
Change-Id: Icd46198a2980f4b4e17ac18367a006d5e4a33c69
diff --git a/src/pool-manager-impl.h b/src/pool-manager-impl.h
new file mode 100644
index 0000000..d8ea6b6
--- /dev/null
+++ b/src/pool-manager-impl.h
@@ -0,0 +1,521 @@
+// Copyright 2017, VIXL authors
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+// * Neither the name of ARM Limited nor the names of its contributors may be
+// used to endorse or promote products derived from this software without
+// specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
+// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef VIXL_POOL_MANAGER_IMPL_H_
+#define VIXL_POOL_MANAGER_IMPL_H_
+
+#include "pool-manager.h"
+
+#include <algorithm>
+#include "assembler-base-vixl.h"
+
+namespace vixl {
+
+
+template <typename T>
+T PoolManager<T>::Emit(MacroAssemblerInterface* masm,
+ T pc,
+ int num_bytes,
+ ForwardReference<T>* new_reference,
+ LabelBase<T>* new_object,
+ EmitOption option) {
+ // Make sure that the buffer still has the alignment we think it does.
+ VIXL_ASSERT(IsAligned(masm->AsAssemblerBase()
+ ->GetBuffer()
+ ->GetStartAddress<uintptr_t>(),
+ buffer_alignment_));
+
+ // We should not call this method when the pools are blocked.
+ VIXL_ASSERT(!IsBlocked());
+ if (objects_.empty()) return pc;
+
+ // Emit header.
+ if (option == kBranchRequired) {
+ masm->EmitPoolHeader();
+ // TODO: The pc at this point might not actually be aligned according to
+ // alignment_. This is to support the current AARCH32 MacroAssembler which
+ // does not have a fixed size instruction set. In practice, the pc will be
+ // aligned to the alignment instructions need for the current instruction
+ // set, so we do not need to align it here. All other calculations do take
+ // the alignment into account, which only makes the checkpoint calculations
+ // more conservative when we use T32. Uncomment the following assertion if
+ // the AARCH32 MacroAssembler is modified to only support one ISA at the
+ // time.
+ // VIXL_ASSERT(pc == AlignUp(pc, alignment_));
+ pc += header_size_;
+ } else {
+ // If the header is optional, we might need to add some extra padding to
+ // meet the minimum location of the first object.
+ if (pc < objects_[0].min_location_) {
+ int32_t padding = objects_[0].min_location_ - pc;
+ masm->EmitNopBytes(padding);
+ pc += padding;
+ }
+ }
+
+ PoolObject<T>* existing_object = GetObjectIfTracked(new_object);
+
+ // Go through all objects and emit one by one.
+ for (objects_iter iter = objects_.begin(); iter != objects_.end();) {
+ PoolObject<T>& current = *iter;
+ if (ShouldSkipObject(¤t,
+ pc,
+ num_bytes,
+ new_reference,
+ new_object,
+ existing_object)) {
+ ++iter;
+ continue;
+ }
+ LabelBase<T>* label_base = current.label_base_;
+ T aligned_pc = AlignUp(pc, current.alignment_);
+ masm->EmitPaddingBytes(aligned_pc - pc);
+ pc = aligned_pc;
+ VIXL_ASSERT(pc >= current.min_location_);
+ VIXL_ASSERT(pc <= current.max_location_);
+ // First call SetLocation, which will also resolve the references, and then
+ // call EmitPoolObject, which might add a new reference.
+ label_base->SetLocation(masm->AsAssemblerBase(), pc);
+ label_base->EmitPoolObject(masm);
+ if (label_base->ShouldDeletePoolObjectOnPlacement()) {
+ label_base->MarkBound();
+ iter = RemoveAndDelete(iter);
+ } else {
+ VIXL_ASSERT(!current.label_base_->ShouldDeletePoolObjectOnPlacement());
+ current.label_base_->UpdatePoolObject(¤t);
+ VIXL_ASSERT(current.alignment_ >= label_base->GetPoolObjectAlignment());
+ ++iter;
+ }
+ pc += label_base->GetPoolObjectSizeInBytes();
+ }
+
+ // Recalculate the checkpoint before emitting the footer. The footer might
+ // call Bind() which will check if we need to emit.
+ RecalculateCheckpoint();
+
+ // Always emit footer - this might add some padding.
+ masm->EmitPoolFooter();
+ pc = AlignUp(pc, alignment_);
+
+ return pc;
+}
+
+template <typename T>
+bool PoolManager<T>::ShouldSkipObject(PoolObject<T>* pool_object,
+ T pc,
+ int num_bytes,
+ ForwardReference<T>* new_reference,
+ LabelBase<T>* new_object,
+ PoolObject<T>* existing_object) const {
+ // We assume that all objects before this have been skipped and all objects
+ // after this will be emitted, therefore we will emit the whole pool. Add
+ // the header size and alignment, as well as the number of bytes we are
+ // planning to emit.
+ T max_actual_location = pc + num_bytes + max_pool_size_;
+
+ if (new_reference != NULL) {
+ // If we're adding a new object, also assume that it will have to be emitted
+ // before the object we are considering to skip.
+ VIXL_ASSERT(new_object != NULL);
+ T new_object_alignment = std::max(new_reference->object_alignment_,
+ new_object->GetPoolObjectAlignment());
+ if ((existing_object != NULL) &&
+ (existing_object->alignment_ > new_object_alignment)) {
+ new_object_alignment = existing_object->alignment_;
+ }
+ max_actual_location +=
+ (new_object->GetPoolObjectSizeInBytes() + new_object_alignment - 1);
+ }
+
+ // Hard limit.
+ if (max_actual_location >= pool_object->max_location_) return false;
+
+ // Use heuristic.
+ return (pc < pool_object->skip_until_location_hint_);
+}
+
+template <typename T>
+T PoolManager<T>::UpdateCheckpointForObject(T checkpoint,
+ const PoolObject<T>* object) {
+ checkpoint -= object->label_base_->GetPoolObjectSizeInBytes();
+ if (checkpoint > object->max_location_) checkpoint = object->max_location_;
+ checkpoint = AlignDown(checkpoint, object->alignment_);
+ return checkpoint;
+}
+
+template <typename T>
+static T MaxCheckpoint() {
+ return std::numeric_limits<T>::max();
+}
+
+template <typename T>
+static inline bool CheckCurrentPC(T pc, T checkpoint) {
+ VIXL_ASSERT(pc <= checkpoint);
+ // We must emit the pools if we are at the checkpoint now.
+ return pc == checkpoint;
+}
+
+template <typename T>
+static inline bool CheckFuturePC(T pc, T checkpoint) {
+ // We do not need to emit the pools now if the projected future PC will be
+ // equal to the checkpoint (we will need to emit the pools then).
+ return pc > checkpoint;
+}
+
+template <typename T>
+bool PoolManager<T>::MustEmit(T pc,
+ int num_bytes,
+ ForwardReference<T>* reference,
+ LabelBase<T>* label_base) const {
+ // Check if we are at or past the checkpoint.
+ if (CheckCurrentPC(pc, checkpoint_)) return true;
+
+ // Check if the future PC will be past the checkpoint.
+ pc += num_bytes;
+ if (CheckFuturePC(pc, checkpoint_)) return true;
+
+ // No new reference - nothing to do.
+ if (reference == NULL) {
+ VIXL_ASSERT(label_base == NULL);
+ return false;
+ }
+
+ if (objects_.empty()) {
+ // Basic assertions that restrictions on the new (and only) reference are
+ // possible to satisfy.
+ VIXL_ASSERT(AlignUp(pc + header_size_, alignment_) >=
+ reference->min_object_location_);
+ VIXL_ASSERT(pc <= reference->max_object_location_);
+ return false;
+ }
+
+ // Check if the object is already being tracked.
+ const PoolObject<T>* existing_object = GetObjectIfTracked(label_base);
+ if (existing_object != NULL) {
+ // If the existing_object is already in existing_objects_ and its new
+ // alignment and new location restrictions are not stricter, skip the more
+ // expensive check.
+ if ((reference->min_object_location_ <= existing_object->min_location_) &&
+ (reference->max_object_location_ >= existing_object->max_location_) &&
+ (reference->object_alignment_ <= existing_object->alignment_)) {
+ return false;
+ }
+ }
+
+ // Create a temporary object.
+ PoolObject<T> temp(label_base);
+ temp.RestrictRange(reference->min_object_location_,
+ reference->max_object_location_);
+ temp.RestrictAlignment(reference->object_alignment_);
+ if (existing_object != NULL) {
+ temp.RestrictRange(existing_object->min_location_,
+ existing_object->max_location_);
+ temp.RestrictAlignment(existing_object->alignment_);
+ }
+
+ // Check if the new reference can be added after the end of the current pool.
+ // If yes, we don't need to emit.
+ T last_reachable = AlignDown(temp.max_location_, temp.alignment_);
+ const PoolObject<T>& last = objects_.back();
+ T after_pool = AlignDown(last.max_location_, last.alignment_) +
+ last.label_base_->GetPoolObjectSizeInBytes();
+ // The current object can be placed at the end of the pool, even if the last
+ // object is placed at the last possible location.
+ if (last_reachable >= after_pool) return false;
+ // The current object can be placed after the code we are about to emit and
+ // after the existing pool (with a pessimistic size estimate).
+ if (last_reachable >= pc + num_bytes + max_pool_size_) return false;
+
+ // We're not in a trivial case, so we need to recalculate the checkpoint.
+
+ // Check (conservatively) if we can fit it into the objects_ array, without
+ // breaking our assumptions. Here we want to recalculate the checkpoint as
+ // if the new reference was added to the PoolManager but without actually
+ // adding it (as removing it is non-trivial).
+
+ T checkpoint = MaxCheckpoint<T>();
+ // Will temp be the last object in objects_?
+ if (PoolObjectLessThan(last, temp)) {
+ checkpoint = UpdateCheckpointForObject(checkpoint, &temp);
+ if (checkpoint < temp.min_location_) return true;
+ }
+
+ bool tempNotPlacedYet = true;
+ for (int i = static_cast<int>(objects_.size()) - 1; i >= 0; --i) {
+ const PoolObject<T>& current = objects_[i];
+ if (tempNotPlacedYet && PoolObjectLessThan(current, temp)) {
+ checkpoint = UpdateCheckpointForObject(checkpoint, &temp);
+ if (checkpoint < temp.min_location_) return true;
+ if (CheckFuturePC(pc, checkpoint)) return true;
+ tempNotPlacedYet = false;
+ }
+ if (current.label_base_ == label_base) continue;
+ checkpoint = UpdateCheckpointForObject(checkpoint, ¤t);
+ if (checkpoint < current.min_location_) return true;
+ if (CheckFuturePC(pc, checkpoint)) return true;
+ }
+ // temp is the object with the smallest max_location_.
+ if (tempNotPlacedYet) {
+ checkpoint = UpdateCheckpointForObject(checkpoint, &temp);
+ if (checkpoint < temp.min_location_) return true;
+ }
+
+ // Take the header into account.
+ checkpoint -= header_size_;
+ checkpoint = AlignDown(checkpoint, alignment_);
+
+ return CheckFuturePC(pc, checkpoint);
+}
+
+template <typename T>
+void PoolManager<T>::RecalculateCheckpoint(SortOption sort_option) {
+ // TODO: Improve the max_pool_size_ estimate by starting from the
+ // min_location_ of the first object, calculating the end of the pool as if
+ // all objects were placed starting from there, and in the end adding the
+ // maximum object alignment found minus one (which is the maximum extra
+ // padding we would need if we were to relocate the pool to a different
+ // address).
+ max_pool_size_ = 0;
+
+ if (objects_.empty()) {
+ checkpoint_ = MaxCheckpoint<T>();
+ return;
+ }
+
+ // Sort objects by their max_location_.
+ if (sort_option == kSortRequired) {
+ std::sort(objects_.begin(), objects_.end(), PoolObjectLessThan);
+ }
+
+ // Add the header size and header and footer max alignment to the maximum
+ // pool size.
+ max_pool_size_ += header_size_ + 2 * (alignment_ - 1);
+
+ T checkpoint = MaxCheckpoint<T>();
+ int last_object_index = static_cast<int>(objects_.size()) - 1;
+ for (int i = last_object_index; i >= 0; --i) {
+ // Bring back the checkpoint by the size of the current object, unless
+ // we need to bring it back more, then align.
+ PoolObject<T>& current = objects_[i];
+ checkpoint = UpdateCheckpointForObject(checkpoint, ¤t);
+ VIXL_ASSERT(checkpoint >= current.min_location_);
+ max_pool_size_ += (current.alignment_ - 1 +
+ current.label_base_->GetPoolObjectSizeInBytes());
+ }
+ // Take the header into account.
+ checkpoint -= header_size_;
+ checkpoint = AlignDown(checkpoint, alignment_);
+
+ // Update the checkpoint of the pool manager.
+ checkpoint_ = checkpoint;
+
+ // NOTE: To handle min_location_ in the generic case, we could make a second
+ // pass of the objects_ vector, increasing the checkpoint as needed, while
+ // maintaining the alignment requirements.
+ // It should not be possible to have any issues with min_location_ with actual
+ // code, since there should always be some kind of branch over the pool,
+ // whether introduced by the pool emission or by the user, which will make
+ // sure the min_location_ requirement is satisfied. It's possible that the
+ // user could emit code in the literal pool and intentionally load the first
+ // value and then fall-through into the pool, but that is not a supported use
+ // of VIXL and we will assert in that case.
+}
+
+template <typename T>
+bool PoolManager<T>::PoolObjectLessThan(const PoolObject<T>& a,
+ const PoolObject<T>& b) {
+ if (a.max_location_ != b.max_location_)
+ return (a.max_location_ < b.max_location_);
+ int a_size = a.label_base_->GetPoolObjectSizeInBytes();
+ int b_size = b.label_base_->GetPoolObjectSizeInBytes();
+ if (a_size != b_size) return (a_size < b_size);
+ if (a.alignment_ != b.alignment_) return (a.alignment_ < b.alignment_);
+ if (a.min_location_ != b.min_location_)
+ return (a.min_location_ < b.min_location_);
+ return false;
+}
+
+template <typename T>
+void PoolManager<T>::AddObjectReference(const ForwardReference<T>* reference,
+ LabelBase<T>* label_base) {
+ VIXL_ASSERT(reference->object_alignment_ <= buffer_alignment_);
+ VIXL_ASSERT(label_base->GetPoolObjectAlignment() <= buffer_alignment_);
+
+ PoolObject<T>* object = GetObjectIfTracked(label_base);
+
+ if (object == NULL) {
+ PoolObject<T> new_object(label_base);
+ new_object.RestrictRange(reference->min_object_location_,
+ reference->max_object_location_);
+ new_object.RestrictAlignment(reference->object_alignment_);
+ Insert(new_object);
+ } else {
+ object->RestrictRange(reference->min_object_location_,
+ reference->max_object_location_);
+ object->RestrictAlignment(reference->object_alignment_);
+
+ // Move the object, if needed.
+ if (objects_.size() != 1) {
+ PoolObject<T> new_object(*object);
+ ptrdiff_t distance = std::distance(objects_.data(), object);
+ objects_.erase(objects_.begin() + distance);
+ Insert(new_object);
+ }
+ }
+ // No need to sort, we inserted the object in an already sorted array.
+ RecalculateCheckpoint(kNoSortRequired);
+}
+
+template <typename T>
+void PoolManager<T>::Insert(const PoolObject<T>& new_object) {
+ bool inserted = false;
+ // Place the object in the right position.
+ for (objects_iter iter = objects_.begin(); iter != objects_.end(); ++iter) {
+ PoolObject<T>& current = *iter;
+ if (!PoolObjectLessThan(current, new_object)) {
+ objects_.insert(iter, new_object);
+ inserted = true;
+ break;
+ }
+ }
+ if (!inserted) {
+ objects_.push_back(new_object);
+ }
+}
+
+template <typename T>
+void PoolManager<T>::RemoveAndDelete(PoolObject<T>* object) {
+ for (objects_iter iter = objects_.begin(); iter != objects_.end(); ++iter) {
+ PoolObject<T>& current = *iter;
+ if (current.label_base_ == object->label_base_) {
+ (void)RemoveAndDelete(iter);
+ return;
+ }
+ }
+ VIXL_UNREACHABLE();
+}
+
+template <typename T>
+typename PoolManager<T>::objects_iter PoolManager<T>::RemoveAndDelete(
+ objects_iter iter) {
+ PoolObject<T>& object = *iter;
+ LabelBase<T>* label_base = object.label_base_;
+
+ // Check if we also need to delete the LabelBase object.
+ if (label_base->ShouldBeDeletedOnPoolManagerDestruction()) {
+ delete_on_destruction_.push_back(label_base);
+ }
+ if (label_base->ShouldBeDeletedOnPlacementByPoolManager()) {
+ VIXL_ASSERT(!label_base->ShouldBeDeletedOnPoolManagerDestruction());
+ delete label_base;
+ }
+
+ return objects_.erase(iter);
+}
+
+template <typename T>
+T PoolManager<T>::Bind(MacroAssemblerInterface* masm,
+ LabelBase<T>* object,
+ T location) {
+ PoolObject<T>* existing_object = GetObjectIfTracked(object);
+ int alignment;
+ T min_location;
+ if (existing_object == NULL) {
+ alignment = object->GetMaxAlignment();
+ min_location = object->GetMinLocation();
+ } else {
+ alignment = existing_object->alignment_;
+ min_location = existing_object->min_location_;
+ }
+
+ // Align if needed, and add necessary padding to reach the min_location_.
+ T aligned_location = AlignUp(location, alignment);
+ masm->EmitNopBytes(aligned_location - location);
+ location = aligned_location;
+ while (location < min_location) {
+ masm->EmitNopBytes(alignment);
+ location += alignment;
+ }
+
+ object->SetLocation(masm->AsAssemblerBase(), location);
+ object->MarkBound();
+
+ if (existing_object != NULL) {
+ RemoveAndDelete(existing_object);
+ // No need to sort, we removed the object from a sorted array.
+ RecalculateCheckpoint(kNoSortRequired);
+ }
+
+ // We assume that the maximum padding we can possibly add here is less
+ // than the header alignment - hence that we're not going to go past our
+ // checkpoint.
+ VIXL_ASSERT(!CheckFuturePC(location, checkpoint_));
+ return location;
+}
+
+template <typename T>
+void PoolManager<T>::Release(T pc) {
+ USE(pc);
+ if (--monitor_ == 0) {
+ // Ensure the pool has not been blocked for too long.
+ VIXL_ASSERT(pc <= checkpoint_);
+ }
+}
+
+template <typename T>
+PoolManager<T>::~PoolManager<T>() {
+#ifdef VIXL_DEBUG
+ // Check for unbound objects.
+ for (objects_iter iter = objects_.begin(); iter != objects_.end(); ++iter) {
+ // There should not be any bound objects left in the pool. For unbound
+ // objects, we will check in the destructor of the object itself.
+ VIXL_ASSERT(!(*iter).label_base_->IsBound());
+ }
+#endif
+ // Delete objects the pool manager owns.
+ for (typename std::vector<LabelBase<T>*>::iterator
+ iter = delete_on_destruction_.begin(),
+ end = delete_on_destruction_.end();
+ iter != end;
+ ++iter) {
+ delete *iter;
+ }
+}
+
+template <typename T>
+int PoolManager<T>::GetPoolSizeForTest() const {
+ // Iterate over objects and return their cumulative size. This does not take
+ // any padding into account, just the size of the objects themselves.
+ int size = 0;
+ for (const_objects_iter iter = objects_.begin(); iter != objects_.end();
+ ++iter) {
+ size += (*iter).label_base_->GetPoolObjectSizeInBytes();
+ }
+ return size;
+}
+}
+
+#endif // VIXL_POOL_MANAGER_IMPL_H_