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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
/*XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XX XX
XX ObjectAllocator XX
XX XX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
*/
#include "jitpch.h"
#ifdef _MSC_VER
#pragma hdrstop
#endif
//===============================================================================
//------------------------------------------------------------------------
// DoPhase: Run analysis (if object stack allocation is enabled) and then
// morph each GT_ALLOCOBJ node either into an allocation helper
// call or stack allocation.
// Notes:
// Runs only if Compiler::optMethodFlags has flag OMF_HAS_NEWOBJ set.
void ObjectAllocator::DoPhase()
{
if ((comp->optMethodFlags & OMF_HAS_NEWOBJ) == 0)
{
return;
}
if (IsObjectStackAllocationEnabled())
{
DoAnalysis();
}
MorphAllocObjNodes();
}
//------------------------------------------------------------------------
// DoAnalysis: Walk over basic blocks of the method and detect all local
// variables that can be allocated on the stack.
//
// Assumptions:
// Must be run after the dominators have been computed (we need this
// information to detect loops).
void ObjectAllocator::DoAnalysis()
{
assert(m_IsObjectStackAllocationEnabled);
assert(comp->fgDomsComputed);
// TODO-ObjectStackAllocation
NYI("DoAnalysis");
}
//------------------------------------------------------------------------
// MorphAllocObjNodes: Morph each GT_ALLOCOBJ node either into an
// allocation helper call or stack allocation.
//
// Notes:
// Runs only over the blocks having bbFlags BBF_HAS_NEWOBJ set.
void ObjectAllocator::MorphAllocObjNodes()
{
BasicBlock* block;
foreach_block(comp, block)
{
const bool basicBlockHasNewObj = (block->bbFlags & BBF_HAS_NEWOBJ) == BBF_HAS_NEWOBJ;
#ifndef DEBUG
if (!basicBlockHasNewObj)
{
continue;
}
#endif // DEBUG
for (GenTreeStmt* stmt = block->firstStmt(); stmt; stmt = stmt->gtNextStmt)
{
GenTree* stmtExpr = stmt->gtStmtExpr;
GenTree* op2 = nullptr;
bool canonicalAllocObjFound = false;
if (stmtExpr->OperGet() == GT_ASG && stmtExpr->TypeGet() == TYP_REF)
{
op2 = stmtExpr->gtGetOp2();
if (op2->OperGet() == GT_ALLOCOBJ)
{
canonicalAllocObjFound = true;
}
}
if (canonicalAllocObjFound)
{
assert(basicBlockHasNewObj);
//------------------------------------------------------------------------
// We expect the following expression tree at this point
// * GT_STMT void (top level)
// | /--* GT_ALLOCOBJ ref
// \--* GT_ASG ref
// \--* GT_LCL_VAR ref
//------------------------------------------------------------------------
GenTree* op1 = stmtExpr->gtGetOp1();
assert(op1->OperGet() == GT_LCL_VAR);
assert(op1->TypeGet() == TYP_REF);
assert(op2 != nullptr);
assert(op2->OperGet() == GT_ALLOCOBJ);
GenTreeAllocObj* asAllocObj = op2->AsAllocObj();
unsigned int lclNum = op1->AsLclVar()->GetLclNum();
if (IsObjectStackAllocationEnabled() && CanAllocateLclVarOnStack(lclNum))
{
op2 = MorphAllocObjNodeIntoStackAlloc(asAllocObj, block, stmt);
}
else
{
op2 = MorphAllocObjNodeIntoHelperCall(asAllocObj);
}
// Propagate flags of op2 to its parent.
stmtExpr->gtOp.gtOp2 = op2;
stmtExpr->gtFlags |= op2->gtFlags & GTF_ALL_EFFECT;
}
#ifdef DEBUG
else
{
// We assume that GT_ALLOCOBJ nodes are always present in the
// canonical form.
comp->fgWalkTreePre(&stmt->gtStmtExpr, AssertWhenAllocObjFoundVisitor);
}
#endif // DEBUG
}
}
}
//------------------------------------------------------------------------
// MorphAllocObjNodeIntoHelperCall: Morph a GT_ALLOCOBJ node into an
// allocation helper call.
//
// Arguments:
// allocObj - GT_ALLOCOBJ that will be replaced by helper call.
//
// Return Value:
// Address of helper call node (can be the same as allocObj).
//
// Notes:
// Must update parents flags after this.
GenTree* ObjectAllocator::MorphAllocObjNodeIntoHelperCall(GenTreeAllocObj* allocObj)
{
assert(allocObj != nullptr);
GenTree* op1 = allocObj->gtGetOp1();
GenTree* helperCall = comp->fgMorphIntoHelperCall(allocObj, allocObj->gtNewHelper, comp->gtNewArgList(op1));
return helperCall;
}
//------------------------------------------------------------------------
// MorphAllocObjNodeIntoStackAlloc: Morph a GT_ALLOCOBJ node into stack
// allocation.
// Arguments:
// allocObj - GT_ALLOCOBJ that will be replaced by helper call.
// block - a basic block where allocObj is
// stmt - a statement where allocObj is
//
// Return Value:
// Address of tree doing stack allocation (can be the same as allocObj).
//
// Notes:
// Must update parents flags after this.
// This function can insert additional statements before stmt.
GenTree* ObjectAllocator::MorphAllocObjNodeIntoStackAlloc(GenTreeAllocObj* allocObj,
BasicBlock* block,
GenTreeStmt* stmt)
{
assert(allocObj != nullptr);
assert(m_AnalysisDone);
// TODO-StackAllocation
NYI("MorphAllocObjIntoStackAlloc");
return allocObj;
}
#ifdef DEBUG
//------------------------------------------------------------------------
// AssertWhenAllocObjFoundVisitor: Look for a GT_ALLOCOBJ node and assert
// when found one.
Compiler::fgWalkResult ObjectAllocator::AssertWhenAllocObjFoundVisitor(GenTree** pTree, Compiler::fgWalkData* data)
{
GenTree* tree = *pTree;
assert(tree != nullptr);
assert(tree->OperGet() != GT_ALLOCOBJ);
return Compiler::fgWalkResult::WALK_CONTINUE;
}
#endif // DEBUG
//===============================================================================
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