DIExpressionOptimizer.cpp File Reference

#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/IR/DebugInfoMetadata.h"

Go to the source code of this file.

Functions
static std::optional< uint64_t >	isConstantVal (DIExpression::ExprOperand Op)
	Returns true if the Op is a DW_OP_constu.
static bool	isNeutralElement (uint64_t Op, uint64_t Val)
	Returns true if an operation and operand result in a No Op.
static std::optional< uint64_t >	foldOperationIfPossible (uint64_t Const1, uint64_t Const2, dwarf::LocationAtom Operator)
	Try to fold Const1 and Const2 by applying Operator and returning the result, if there is an overflow, return a std::nullopt.
static bool	operationsAreFoldableAndCommutative (dwarf::LocationAtom Operator1, dwarf::LocationAtom Operator2)
	Returns true if the two operations Operator1 and Operator2 are commutative and can be folded.
static void	consumeOneOperator (DIExpressionCursor &Cursor, uint64_t &Loc, const DIExpression::ExprOperand &Op)
	Consume one operator and its operand(s).
void	startFromBeginning (uint64_t &Loc, DIExpressionCursor &Cursor, ArrayRef< uint64_t > WorkingOps)
	Reset the Cursor to the beginning of the WorkingOps.
static SmallVector< uint64_t >	canonicalizeDwarfOperations (ArrayRef< uint64_t > WorkingOps)
	This function will canonicalize:
static SmallVector< uint64_t >	optimizeDwarfOperations (ArrayRef< uint64_t > WorkingOps)
	This function will convert:
static bool	tryFoldNoOpMath (uint64_t Const1, ArrayRef< DIExpression::ExprOperand > Ops, uint64_t &Loc, DIExpressionCursor &Cursor, SmallVectorImpl< uint64_t > &WorkingOps)
	{DW_OP_constu, 0, DW_OP_[plus, minus, shl, shr]} -> {} {DW_OP_constu, 1, DW_OP_[mul, div]} -> {}
static bool	tryFoldConstants (uint64_t Const1, ArrayRef< DIExpression::ExprOperand > Ops, uint64_t &Loc, DIExpressionCursor &Cursor, SmallVectorImpl< uint64_t > &WorkingOps)
	{DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_[plus, minus, mul, div, shl, shr] -> {DW_OP_constu, Const1 [+, -, *, /, <<, >>] Const2}
static bool	tryFoldCommutativeMath (uint64_t Const1, ArrayRef< DIExpression::ExprOperand > Ops, uint64_t &Loc, DIExpressionCursor &Cursor, SmallVectorImpl< uint64_t > &WorkingOps)
	{DW_OP_constu, Const1, DW_OP_[plus, mul], DW_OP_constu, Const2, DW_OP_[plus, mul]} -> {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus, mul]}
static bool	tryFoldCommutativeMathWithArgInBetween (uint64_t Const1, ArrayRef< DIExpression::ExprOperand > Ops, uint64_t &Loc, DIExpressionCursor &Cursor, SmallVectorImpl< uint64_t > &WorkingOps)
	{DW_OP_constu, Const1, DW_OP_[plus, mul], DW_OP_LLVM_arg, Arg1, DW_OP_[plus, mul], DW_OP_constu, Const2, DW_OP_[plus, mul]} -> {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus, mul], DW_OP_LLVM_arg, Arg1, DW_OP_[plus, mul]}

Function Documentation

canonicalizeDwarfOperations()

static SmallVector< uint64_t > canonicalizeDwarfOperations ( ArrayRef< uint64_t >  WorkingOps )

static

This function will canonicalize:

1. DW_OP_plus_uconst to DW_OP_constu <const-val> DW_OP_plus
2. DW_OP_lit<n> to DW_OP_constu <n>

Expression has no operations, break.

Definition at line 115 of file DIExpressionOptimizer.cpp.

References llvm::SmallVectorImpl< T >::append(), llvm::ArrayRef< T >::begin(), consumeOneOperator(), llvm::DIExpressionCursor::peek(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::ArrayRef< T >::size().

Referenced by llvm::DIExpression::foldConstantMath().

consumeOneOperator()

static void consumeOneOperator ( DIExpressionCursor &  Cursor, uint64_t &  Loc, const DIExpression::ExprOperand &  Op  )

static

Consume one operator and its operand(s).

Definition at line 98 of file DIExpressionOptimizer.cpp.

References llvm::DIExpressionCursor::consume().

Referenced by canonicalizeDwarfOperations(), llvm::DIExpression::foldConstantMath(), optimizeDwarfOperations(), tryFoldCommutativeMath(), tryFoldCommutativeMathWithArgInBetween(), and tryFoldConstants().

foldOperationIfPossible()

static std::optional< uint64_t > foldOperationIfPossible ( uint64_t  Const1, uint64_t  Const2, dwarf::LocationAtom  Operator  )

static

Try to fold Const1 and Const2 by applying Operator and returning the result, if there is an overflow, return a std::nullopt.

Definition at line 45 of file DIExpressionOptimizer.cpp.

References llvm::countl_zero(), llvm::countr_zero(), llvm::SaturatingAdd(), and llvm::SaturatingMultiply().

Referenced by tryFoldCommutativeMath(), tryFoldCommutativeMathWithArgInBetween(), and tryFoldConstants().

isConstantVal()

static std::optional< uint64_t > isConstantVal ( DIExpression::ExprOperand  Op )

static

Returns true if the Op is a DW_OP_constu.

Definition at line 20 of file DIExpressionOptimizer.cpp.

Referenced by llvm::DIExpression::foldConstantMath(), tryFoldCommutativeMath(), tryFoldCommutativeMathWithArgInBetween(), and tryFoldConstants().

isNeutralElement()

static bool isNeutralElement ( uint64_t  Op, uint64_t  Val  )

static

Returns true if an operation and operand result in a No Op.

Definition at line 27 of file DIExpressionOptimizer.cpp.

Referenced by tryFoldNoOpMath().

operationsAreFoldableAndCommutative()

static bool operationsAreFoldableAndCommutative ( dwarf::LocationAtom  Operator1, dwarf::LocationAtom  Operator2  )

static

Returns true if the two operations Operator1 and Operator2 are commutative and can be folded.

Definition at line 91 of file DIExpressionOptimizer.cpp.

Referenced by tryFoldCommutativeMath(), and tryFoldCommutativeMathWithArgInBetween().

optimizeDwarfOperations()

static SmallVector< uint64_t > optimizeDwarfOperations ( ArrayRef< uint64_t >  WorkingOps )

static

This function will convert:

1. DW_OP_constu <const-val> DW_OP_plus to DW_OP_plus_uconst
2. DW_OP_constu, 0 to DW_OP_lit0

Expression has no operations, exit.

Expression has no more operations, copy into ResultOps and exit.

Definition at line 150 of file DIExpressionOptimizer.cpp.

References llvm::SmallVectorImpl< T >::append(), llvm::ArrayRef< T >::begin(), consumeOneOperator(), llvm::DIExpressionCursor::peek(), llvm::DIExpressionCursor::peekNext(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::ArrayRef< T >::size().

Referenced by llvm::DIExpression::foldConstantMath().

startFromBeginning()

void startFromBeginning	(	uint64_t &	Loc,
		DIExpressionCursor &	Cursor,
		ArrayRef< uint64_t >	WorkingOps
	)

Reset the Cursor to the beginning of the WorkingOps.

Definition at line 105 of file DIExpressionOptimizer.cpp.

References llvm::DIExpressionCursor::assignNewExpr().

Referenced by tryFoldCommutativeMath(), tryFoldCommutativeMathWithArgInBetween(), tryFoldConstants(), and tryFoldNoOpMath().

tryFoldCommutativeMath()

static bool tryFoldCommutativeMath ( uint64_t  Const1, ArrayRef< DIExpression::ExprOperand >  Ops, uint64_t &  Loc, DIExpressionCursor &  Cursor, SmallVectorImpl< uint64_t > &  WorkingOps  )

static

{DW_OP_constu, Const1, DW_OP_[plus, mul], DW_OP_constu, Const2, DW_OP_[plus, mul]} -> {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus, mul]}

Definition at line 234 of file DIExpressionOptimizer.cpp.

References llvm::SmallVectorTemplateCommon< T, typename >::begin(), consumeOneOperator(), llvm::SmallVectorImpl< T >::erase(), foldOperationIfPossible(), isConstantVal(), operationsAreFoldableAndCommutative(), and startFromBeginning().

Referenced by llvm::DIExpression::foldConstantMath().

tryFoldCommutativeMathWithArgInBetween()

static bool tryFoldCommutativeMathWithArgInBetween ( uint64_t  Const1, ArrayRef< DIExpression::ExprOperand >  Ops, uint64_t &  Loc, DIExpressionCursor &  Cursor, SmallVectorImpl< uint64_t > &  WorkingOps  )

static

{DW_OP_constu, Const1, DW_OP_[plus, mul], DW_OP_LLVM_arg, Arg1, DW_OP_[plus, mul], DW_OP_constu, Const2, DW_OP_[plus, mul]} -> {DW_OP_constu, Const1 [+, *] Const2, DW_OP_[plus, mul], DW_OP_LLVM_arg, Arg1, DW_OP_[plus, mul]}

Definition at line 262 of file DIExpressionOptimizer.cpp.

References llvm::SmallVectorTemplateCommon< T, typename >::begin(), consumeOneOperator(), llvm::dwarf::DW_OP_LLVM_arg, llvm::SmallVectorImpl< T >::erase(), foldOperationIfPossible(), isConstantVal(), operationsAreFoldableAndCommutative(), and startFromBeginning().

Referenced by llvm::DIExpression::foldConstantMath().

tryFoldConstants()

static bool tryFoldConstants ( uint64_t  Const1, ArrayRef< DIExpression::ExprOperand >  Ops, uint64_t &  Loc, DIExpressionCursor &  Cursor, SmallVectorImpl< uint64_t > &  WorkingOps  )

static

{DW_OP_constu, Const1, DW_OP_constu, Const2, DW_OP_[plus, minus, mul, div, shl, shr] -> {DW_OP_constu, Const1 [+, -, *, /, <<, >>] Const2}

Definition at line 209 of file DIExpressionOptimizer.cpp.

References llvm::SmallVectorTemplateCommon< T, typename >::begin(), consumeOneOperator(), llvm::SmallVectorImpl< T >::erase(), foldOperationIfPossible(), isConstantVal(), and startFromBeginning().

Referenced by llvm::DIExpression::foldConstantMath().

tryFoldNoOpMath()

static bool tryFoldNoOpMath ( uint64_t  Const1, ArrayRef< DIExpression::ExprOperand >  Ops, uint64_t &  Loc, DIExpressionCursor &  Cursor, SmallVectorImpl< uint64_t > &  WorkingOps  )

static

{DW_OP_constu, 0, DW_OP_[plus, minus, shl, shr]} -> {} {DW_OP_constu, 1, DW_OP_[mul, div]} -> {}

Definition at line 193 of file DIExpressionOptimizer.cpp.

References llvm::SmallVectorTemplateCommon< T, typename >::begin(), llvm::SmallVectorImpl< T >::erase(), isNeutralElement(), and startFromBeginning().

Referenced by llvm::DIExpression::foldConstantMath().