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JIT: remember indir store addresses in escape analysis #115689

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1 change: 1 addition & 0 deletions src/coreclr/jit/jitconfigvalues.h
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Original file line number Diff line number Diff line change
Expand Up @@ -685,6 +685,7 @@ RELEASE_CONFIG_INTEGER(JitObjectStackAllocationArray, "JitObjectStackAllocationA
RELEASE_CONFIG_INTEGER(JitObjectStackAllocationSize, "JitObjectStackAllocationSize", 528)
RELEASE_CONFIG_INTEGER(JitObjectStackAllocationTrackFields, "JitObjectStackAllocationTrackFields", 1)
CONFIG_STRING(JitObjectStackAllocationTrackFieldsRange, "JitObjectStackAllocationTrackFieldsRange")
CONFIG_INTEGER(JitObjectStackAllocationDumpConnGraph, "JitObjectStackAllocationDumpConnGraph", 0)

RELEASE_CONFIG_INTEGER(JitEECallTimingInfo, "JitEECallTimingInfo", 0)

Expand Down
99 changes: 60 additions & 39 deletions src/coreclr/jit/objectalloc.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@ ObjectAllocator::ObjectAllocator(Compiler* comp)
, m_maxPseudos(0)
, m_regionsToClone(0)
, m_trackFields(false)
, m_StoreAddressToIndexMap(comp->getAllocator(CMK_ObjectAllocator))
{
m_EscapingPointers = BitVecOps::UninitVal();
m_PossiblyStackPointingPointers = BitVecOps::UninitVal();
Expand Down Expand Up @@ -564,6 +565,34 @@ void ObjectAllocator::DoAnalysis()
ComputeEscapingNodes(&m_bitVecTraits, m_EscapingPointers);
}

#ifdef DEBUG
// Print the connection graph
//
if (JitConfig.JitObjectStackAllocationDumpConnGraph() > 0)
{
JITDUMP("digraph ConnectionGraph {\n");
for (unsigned int i = 0; i < m_bvCount; i++)
{
BitVecOps::Iter iterator(&m_bitVecTraits, m_ConnGraphAdjacencyMatrix[i]);
unsigned int lclIndex;
while (iterator.NextElem(&lclIndex))
{
JITDUMPEXEC(DumpIndex(lclIndex));
JITDUMP(" -> ");
JITDUMPEXEC(DumpIndex(i));
JITDUMP(";\n");
}

if (CanIndexEscape(i))
{
JITDUMPEXEC(DumpIndex(i));
JITDUMP(" -> E;\n");
}
}
JITDUMP("}\n");
}
#endif

m_AnalysisDone = true;
}

Expand Down Expand Up @@ -1731,6 +1760,7 @@ void ObjectAllocator::AnalyzeParentStack(ArrayStack<GenTree*>* parentStack, unsi
}

// Check whether the local escapes higher up
isAddress = false;
++parentIndex;
keepChecking = true;
break;
Expand All @@ -1755,58 +1785,49 @@ void ObjectAllocator::AnalyzeParentStack(ArrayStack<GenTree*>* parentStack, unsi

case GT_STOREIND:
case GT_STORE_BLK:
case GT_BLK:
{
GenTree* const addr = parent->AsIndir()->Addr();
if (tree == addr)
{
JITDUMP("... store address\n");
if (isAddress)
{
// Remember the resource being stored to.
//
JITDUMP("... store address\n");
m_StoreAddressToIndexMap.Set(tree, lclIndex);
}

// The address does not escape
//
canLclVarEscapeViaParentStack = false;
break;
}

// If the value being stored is a local address, anything assigned to that local escapes
// Is this a store to a tracked resource?
//
if (isAddress)
unsigned dstIndex;
if (m_trackFields && m_StoreAddressToIndexMap.Lookup(addr, &dstIndex) && (dstIndex != BAD_VAR_NUM))
{
break;
}
JITDUMP("... local.field store\n");

// Is this a store to a field of a local struct...?
//
if (parent->OperIs(GT_STOREIND))
{
// Are we storing to a local field?
//
if (addr->OperIs(GT_FIELD_ADDR))
if (!isAddress)
{
// Simple check for which local.
//
GenTree* const base = addr->AsOp()->gtGetOp1();

if (base->OperIs(GT_LCL_ADDR))
{
unsigned const dstLclNum = base->AsLclVarCommon()->GetLclNum();

if (IsTrackedLocal(dstLclNum))
{
JITDUMP("... local.field store\n");
const unsigned dstIndex = LocalToIndex(dstLclNum);
// Add an edge to the connection graph.
//
AddConnGraphEdgeIndex(dstIndex, lclIndex);
canLclVarEscapeViaParentStack = false;
}
}
AddConnGraphEdgeIndex(dstIndex, lclIndex);
canLclVarEscapeViaParentStack = false;
break;
}
else
{
AddConnGraphEdgeIndex(dstIndex, m_unknownSourceIndex);
}

// Else we're storing the value somewhere unknown.
// Assume the worst.
}

// We're storing the value somewhere unknown. Assume the worst.
break;
}

case GT_IND:
case GT_BLK:
{
// Does this load a type we're tracking?
//
Expand All @@ -1820,12 +1841,12 @@ void ObjectAllocator::AnalyzeParentStack(ArrayStack<GenTree*>* parentStack, unsi

// For loads from local structs we may be tracking the underlying fields.
//
// We can assume that the local being read is lclNum, since we have walked up to this node from a leaf
// local.
// We can assume that the local being read is lclNum,
// since we have walked up to this node from a leaf local.
//
// We only track through the first indir.
//
if (m_trackFields && isAddress && addr->OperIs(GT_FIELD_ADDR))
if (m_trackFields && isAddress)
{
JITDUMP("... load local.field\n");
++parentIndex;
Expand Down Expand Up @@ -2076,7 +2097,6 @@ void ObjectAllocator::UpdateAncestorTypes(GenTree* tree,

case GT_STOREIND:
case GT_STORE_BLK:
case GT_BLK:
{
if (tree == parent->AsIndir()->Addr())
{
Expand Down Expand Up @@ -2107,10 +2127,11 @@ void ObjectAllocator::UpdateAncestorTypes(GenTree* tree,
}

case GT_IND:
case GT_BLK:
{
// If we are loading from a GC struct field, we may need to retype the load
//
if (retypeFields && (tree->OperIs(GT_FIELD_ADDR)) && (varTypeIsGC(parent->TypeGet())))
if (retypeFields && (varTypeIsGC(parent->TypeGet())))
{
parent->ChangeType(newType);
++parentIndex;
Expand Down
4 changes: 3 additions & 1 deletion src/coreclr/jit/objectalloc.h
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Expand Up @@ -110,6 +110,7 @@ struct CloneInfo : public GuardInfo
};

typedef JitHashTable<unsigned, JitSmallPrimitiveKeyFuncs<unsigned>, CloneInfo*> CloneMap;
typedef JitHashTable<GenTree*, JitPtrKeyFuncs<GenTree>, unsigned> NodeToIndexMap;

class ObjectAllocator final : public Phase
{
Expand Down Expand Up @@ -148,7 +149,8 @@ class ObjectAllocator final : public Phase
unsigned m_regionsToClone;

// Struct fields
bool m_trackFields;
bool m_trackFields;
NodeToIndexMap m_StoreAddressToIndexMap;

//===============================================================================
// Methods
Expand Down
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