#include <IOBarrier.hpp>

Inheritance diagram for jlm::llvm::IOBarrierOperation:

Collaboration diagram for jlm::llvm::IOBarrierOperation:

Public Member Functions
	~IOBarrierOperation () noexcept override

	IOBarrierOperation (const std::shared_ptr< const rvsdg::Type > &type)

const std::shared_ptr< const rvsdg::Type > &	Type () const noexcept

bool	operator== (const Operation &other) const noexcept override

std::string	debug_string () const override

std::unique_ptr< Operation >	copy () const override

Public Member Functions inherited from jlm::rvsdg::SimpleOperation
	~SimpleOperation () noexcept override

	SimpleOperation (std::vector< std::shared_ptr< const jlm::rvsdg::Type >> operands, std::vector< std::shared_ptr< const jlm::rvsdg::Type >> results)

size_t	narguments () const noexcept

const std::shared_ptr< const rvsdg::Type > &	argument (size_t index) const noexcept

size_t	nresults () const noexcept

const std::shared_ptr< const rvsdg::Type > &	result (size_t index) const noexcept

Public Member Functions inherited from jlm::rvsdg::Operation
virtual	~Operation () noexcept

virtual bool	operator== (const Operation &other) const noexcept=0

bool	operator!= (const Operation &other) const noexcept

Static Public Member Functions
static rvsdg::Input &	BarredInput (const rvsdg::SimpleNode &node) noexcept

static rvsdg::SimpleNode &	createNode (rvsdg::Output &value, rvsdg::Output &ioState)

Detailed Description

An IOBarrier operation is used to sequentialize other operations after other IO state operations. It has no equivalent in LLVM.

Example:

int f(int x)
{
  opaque(); //calls internally exit(0)
  return x / 0;
}

The above code is valid C code and not undefined even though there is a division by zero present. The reason for this is that the function opaque() invokes exit(0), and the division by zero is never performed at runtime. In the RVSDG, the division operation has no dependency on the function call to opaque() and therefore it can happen that it is sequentialized before the call operation, transforming the valid program to an undefined program.

The IOBarrier operation ensures a sequentialization of these two operations by routing one of the division operands through it along with an I/O state as additional operand. The division operation consumes then the result value of the IOBarrier operation, effectively seuqentializing the division after the barrier and with that after the call operation:

... io = Call opaque .... xo = IOBarrier x io ... = ISDiv xo 0

Definition at line 45 of file IOBarrier.hpp.

Constructor & Destructor Documentation

◆ ~IOBarrierOperation()

jlm::llvm::IOBarrierOperation::~IOBarrierOperation ( )

overridedefaultnoexcept

◆ IOBarrierOperation()

jlm::llvm::IOBarrierOperation::IOBarrierOperation ( const std::shared_ptr< const rvsdg::Type > & type )

inlineexplicit

Definition at line 50 of file IOBarrier.hpp.

Member Function Documentation

◆ BarredInput()

static rvsdg::Input& jlm::llvm::IOBarrierOperation::BarredInput ( const rvsdg::SimpleNode & node )

inlinestaticnoexcept

Definition at line 70 of file IOBarrier.hpp.

◆ copy()

std::unique_ptr< rvsdg::Operation > jlm::llvm::IOBarrierOperation::copy ( ) const

overridevirtual

Implements jlm::rvsdg::Operation.

Definition at line 27 of file IOBarrier.cpp.

◆ createNode()

static rvsdg::SimpleNode& jlm::llvm::IOBarrierOperation::createNode	(	rvsdg::Output &	value,
		rvsdg::Output &	ioState
	)

inlinestatic

Definition at line 78 of file IOBarrier.hpp.

◆ debug_string()

std::string jlm::llvm::IOBarrierOperation::debug_string ( ) const

overridevirtual

Implements jlm::rvsdg::Operation.

Definition at line 21 of file IOBarrier.cpp.

◆ operator==()

bool jlm::llvm::IOBarrierOperation::operator== ( const Operation & other ) const

overridenoexcept

Definition at line 14 of file IOBarrier.cpp.

◆ Type()

const std::shared_ptr<const rvsdg::Type>& jlm::llvm::IOBarrierOperation::Type ( ) const

inlinenoexcept

Definition at line 55 of file IOBarrier.hpp.

The documentation for this class was generated from the following files:

jlm/llvm/ir/operators/IOBarrier.hpp
jlm/llvm/ir/operators/IOBarrier.cpp

Public Member Functions

Static Public Member Functions