Stack frames for languages with non local variables. More...

#include <level.hh>

Collaboration diagram for translate::Level:

Public Member Functions
	Level (const misc::symbol &name, const Level *parent=nullptr, frame::bool_list_type formal_escapes=frame::bool_list_type())
	~Level ()
tree::rExp	sl () const
	A Tree expression computing this level's static link.
tree::rExp	fp (const Level &use) const
	Return a Tree expression representing the frame pointer of this Level, but from the use level point of view (i.e., climbing the static links from use level to this Level).
std::ostream &	dump (std::ostream &o) const
	Report on stream o.
const Access *	local_alloc (bool escapes)
	Allocate a new local variable.
const Access *	formal_alloc (bool escapes)
	Similar to local_alloc () for formal arguments.
Accessors.
Level of the enclosing function.
const Level *	parent_get () const
frame::Frame &	frame_get ()
	Stack frame that we enhance with static link support.
const frame::Frame &	frame_get () const
	Stack frame that we enhance with static link support.
temp::Label	label_get () const
	Label of this function (from the Frame).
const access_list_type &	formals_get () const
	Accesses to the formals arguments.
int	frame_size_get () const
	Size of the Frame.

Private Attributes
const Level *	parent_
	Level of the enclosing function.
frame::Frame *	frame_
	Stack frame that we enhance with static link support.
access_list_type	formals_
	Accesses to the formal arguments.
access_list_type	locals_
	Accesses to the local (automatic) variables.

Detailed Description

Stack frames for languages with non local variables.

frame::Frame holds the information on the function stack frame. translate::Level adds information on the parents of the current Level (which is used to fetch escaping variables), and also the list of the Access'es to the formals of the functions.

A frame::Frame is a frame::Access factory, and translate::Level is a translate::Access factory.

Constructor & Destructor Documentation

translate::Level::Level	(	const misc::symbol &	name,
		const Level *	parent = `nullptr`,
		frame::bool_list_type	formal_escapes = `frame::bool_list_type()`
	)

References formal_alloc().

translate::Level::~Level ( )

Destroy \a locals_ completely, but not \a formals_.

locals_ and formals_ are translate::Access binding some frame::Access. The frame::Frame keeps tracks of its formals, but not of its locals; hence it destroys by itself its locals and we must not do it here. As a result, we have to destroy the high level parts of both formals and locals, and the low level part (frame::Access) only for locals_.

References misc::deep_clear(), formals_, and locals_.

Member Function Documentation

std::ostream & translate::Level::dump ( std::ostream & o ) const

Report on stream o.

References misc::decindent(), formals_, frame_, misc::incendl(), label_get(), and parent_.

Referenced by translate::operator<<().

const Access * translate::Level::formal_alloc ( bool escapes )

Similar to local_alloc () for formal arguments.

References frame::Frame::formal_alloc(), formals_, and frame_.

Referenced by Level().

const access_list_type & translate::Level::formals_get ( ) const

inline

Accesses to the formals arguments.

References formals_.

Referenced by sl(), and translate::Translator::visit_function_dec_body().

tree::rExp translate::Level::fp ( const Level & use ) const

Return a Tree expression representing the frame pointer of this Level, but from the use level point of view (i.e., climbing the static links from use level to this Level).

This is used in at least two places:

when calling a function (which needs a static link), to pass the location of the frame of its parent.

when accessing a frame resident variable, to produce an expression computing the location of the frame it belongs to. For instance this is `Temp fp' if the variable is in the function using it, but it is more complex when the function uses a variable from an enclosing function.

Referenced by translate::Access::exp().

frame::Frame & translate::Level::frame_get ( )

inline

Stack frame that we enhance with static link support.

References frame_.

Referenced by label_get(), sl(), and translate::Translator::visit_function_dec_body().

const frame::Frame & translate::Level::frame_get ( ) const

inline

Stack frame that we enhance with static link support.

References frame_.

int translate::Level::frame_size_get ( ) const

Size of the Frame.