[llvm] r261337 - [StatepointLowering] Change AllocatedStackSlots to use SmallBitVector
Sanjoy Das via llvm-commits
llvm-commits at lists.llvm.org
Fri Feb 19 09:15:27 PST 2016
Author: sanjoy
Date: Fri Feb 19 11:15:26 2016
New Revision: 261337
URL: http://llvm.org/viewvc/llvm-project?rev=261337&view=rev
Log:
[StatepointLowering] Change AllocatedStackSlots to use SmallBitVector
NFCI. They key motivation here is that I'd like to use
SmallBitVector::all() in a later change. Also, using a bit vector here
seemed better in general.
The only interesting change here is that in the failure case of
allocateStackSlot, we no longer (the equivalent of) push_back(true) to
AllocatedStackSlots. As far as I can tell, this is fine, since we'd
never re-use those slots in the same StatepointLoweringState instance.
Technically there was no need to change the operator[] type accesses to
set() and test(), but I thought it'd be nice to make it obvious that
we're using something other than a std::vector like thing.
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.h
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.cpp?rev=261337&r1=261336&r2=261337&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.cpp Fri Feb 19 11:15:26 2016
@@ -53,13 +53,10 @@ void StatepointLoweringState::startNewSt
"Trying to visit statepoint before finished processing previous one");
Locations.clear();
NextSlotToAllocate = 0;
- // Need to resize this on each safepoint - we need the two to stay in
- // sync and the clear patterns of a SelectionDAGBuilder have no relation
- // to FunctionLoweringInfo.
+ // Need to resize this on each safepoint - we need the two to stay in sync and
+ // the clear patterns of a SelectionDAGBuilder have no relation to
+ // FunctionLoweringInfo. SmallBitVector::reset initializes all bits to false.
AllocatedStackSlots.resize(Builder.FuncInfo.StatepointStackSlots.size());
- for (size_t i = 0; i < AllocatedStackSlots.size(); i++) {
- AllocatedStackSlots[i] = false;
- }
}
void StatepointLoweringState::clear() {
@@ -85,11 +82,16 @@ StatepointLoweringState::allocateStackSl
const size_t NumSlots = AllocatedStackSlots.size();
assert(NextSlotToAllocate <= NumSlots && "Broken invariant");
+ // The stack slots in StatepointStackSlots beyond the first NumSlots were
+ // added in this instance of StatepointLoweringState, and cannot be re-used.
+ assert(NumSlots <= Builder.FuncInfo.StatepointStackSlots.size() &&
+ "Broken invariant");
+
for (; NextSlotToAllocate < NumSlots; NextSlotToAllocate++) {
- if (!AllocatedStackSlots[NextSlotToAllocate] &&
+ if (!AllocatedStackSlots.test(NextSlotToAllocate) &&
MFI->getObjectSize(NextSlotToAllocate) == SpillSize) {
const int FI = Builder.FuncInfo.StatepointStackSlots[NextSlotToAllocate];
- AllocatedStackSlots[NextSlotToAllocate] = true;
+ AllocatedStackSlots.set(NextSlotToAllocate);
return Builder.DAG.getFrameIndex(FI, ValueType);
}
}
@@ -104,7 +106,6 @@ StatepointLoweringState::allocateStackSl
MFI->markAsStatepointSpillSlotObjectIndex(FI);
Builder.FuncInfo.StatepointStackSlots.push_back(FI);
- AllocatedStackSlots.push_back(true);
return SpillSlot;
}
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.h?rev=261337&r1=261336&r2=261337&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.h (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/StatepointLowering.h Fri Feb 19 11:15:26 2016
@@ -16,6 +16,7 @@
#define LLVM_LIB_CODEGEN_SELECTIONDAG_STATEPOINTLOWERING_H
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallBitVector.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include <vector>
@@ -84,14 +85,14 @@ public:
void reserveStackSlot(int Offset) {
assert(Offset >= 0 && Offset < (int)AllocatedStackSlots.size() &&
"out of bounds");
- assert(!AllocatedStackSlots[Offset] && "already reserved!");
+ assert(!AllocatedStackSlots.test(Offset) && "already reserved!");
assert(NextSlotToAllocate <= (unsigned)Offset && "consistency!");
- AllocatedStackSlots[Offset] = true;
+ AllocatedStackSlots.set(Offset);
}
bool isStackSlotAllocated(int Offset) {
assert(Offset >= 0 && Offset < (int)AllocatedStackSlots.size() &&
"out of bounds");
- return AllocatedStackSlots[Offset];
+ return AllocatedStackSlots.test(Offset);
}
private:
@@ -103,7 +104,7 @@ private:
/// whether it has been used in the current statepoint. Since we try to
/// preserve stack slots across safepoints, there can be gaps in which
/// slots have been allocated.
- SmallVector<bool, 50> AllocatedStackSlots;
+ SmallBitVector AllocatedStackSlots;
/// Points just beyond the last slot known to have been allocated
unsigned NextSlotToAllocate;
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