A memory disambiguator checks whether 2 given SSA values representing addresses alias. More...

Typedefs
typedef ir_alias_relation(*	DISAMBIGUATOR_FUNC )(const ir_node adr1, const ir_mode mode1, const ir_node adr2, const ir_mode mode2)
	A source language specific memory disambiguator function.
Enumerations
enum	ir_alias_relation { ir_no_alias, ir_may_alias, ir_sure_alias }
	The alias relation of two memory addresses. More...
enum	ir_entity_usage_computed_state { ir_entity_usage_not_computed, ir_entity_usage_computed }
	The state of the entity usage flags. More...
enum	ir_disambuigator_options { aa_opt_no_opt = 0, aa_opt_type_based = 1, aa_opt_byte_type_may_alias = 2, aa_opt_no_alias_args = 4, aa_opt_no_alias_args_global = 8, aa_opt_no_alias = 16, aa_opt_inherited = 128 }
	Possible options for the memory disambiguator. More...
enum	ir_storage_class_class_t { ir_sc_pointer = 0x0, ir_sc_globalvar = 0x1, ir_sc_localvar = 0x2, ir_sc_tls = 0x3, ir_sc_malloced = 0x4, ir_sc_globaladdr = 0x5, ir_sc_modifier_nottaken = 0x80, ir_sc_modifier_argument = 0x40, ir_sc_modifiers = ir_sc_modifier_nottaken \| ir_sc_modifier_argument }
	Classify storage locations. More...
Functions
ir_storage_class_class_t	get_base_sc (ir_storage_class_class_t x)
	Returns the base storage class (ignore modifier)
ir_storage_class_class_t	classify_pointer (const ir_node irn, const ir_entity ent)
	Classify a base pointer.
const char *	get_ir_alias_relation_name (ir_alias_relation rel)
	Returns a human readable name for an alias relation.
ir_alias_relation	get_alias_relation (const ir_node adr1, const ir_mode mode1, const ir_node adr2, const ir_mode mode2)
	Determine the alias relation between two addresses.
void	set_language_memory_disambiguator (DISAMBIGUATOR_FUNC func)
	Sets a source language specific memory disambiguator function.
void	mem_disambig_init (void)
	Initialize the relation cache.
ir_alias_relation	get_alias_relation_ex (const ir_node adr1, const ir_mode mode1, const ir_node adr2, const ir_mode mode2)
	Determine the alias relation between two addresses and cache the result.
void	mem_disambig_term (void)
	Free the relation cache.
void	assure_irg_entity_usage_computed (ir_graph *irg)
	Assure that the entity usage flags have been computed for the given graph.
ir_entity_usage_computed_state	get_irp_globals_entity_usage_state (void)
	Returns the current address taken state of the globals.
void	set_irp_globals_entity_usage_state (ir_entity_usage_computed_state state)
	Sets the current address taken state of the globals.
void	assure_irp_globals_entity_usage_computed (void)
	Assure that the address taken flag is computed for the global and TLS entities (variables).
unsigned	get_irg_memory_disambiguator_options (const ir_graph *irg)
	Returns the memory disambiguator options for a graph.
void	set_irg_memory_disambiguator_options (ir_graph *irg, unsigned options)
	Sets the memory disambiguator options for a graph.
void	set_irp_memory_disambiguator_options (unsigned options)
	Sets the global disambiguator options for all graphs not having local options.
void	mark_private_methods (void)
	Mark all private methods, i.e.
ir_prog_pass_t *	mark_private_methods_pass (const char *name)
	Creates an ir_prog pass for mark_private_methods().

Detailed Description

A memory disambiguator checks whether 2 given SSA values representing addresses alias.

Typedef Documentation

typedef ir_alias_relation(* DISAMBIGUATOR_FUNC)(const ir_node *adr1, const ir_mode *mode1, const ir_node *adr2, const ir_mode *mode2)

A source language specific memory disambiguator function.

Called by get_alias_relation().

Definition at line 93 of file irmemory.h.

Enumeration Type Documentation

enum ir_alias_relation

The alias relation of two memory addresses.

Enumerator:

ir_no_alias	No alias.
ir_may_alias	Unknown state, may alias.
ir_sure_alias	Sure alias.

Definition at line 42 of file irmemory.h.

enum ir_disambuigator_options

Possible options for the memory disambiguator.

Enumerator:

aa_opt_no_opt	no options: most conservative
aa_opt_type_based	use type based alias analysis: strict typed source language
aa_opt_byte_type_may_alias	if type based analysis is enabled: bytes types may alias other types
aa_opt_no_alias_args	arguments do not alias each other but may alias global storage
aa_opt_no_alias_args_global	arguments do not alias global storage
aa_opt_no_alias	two addresses NEVER alias, use with CAUTION (gcc -fno-alias)
aa_opt_inherited	only for implementation: options from a graph are inherited from global

Definition at line 55 of file irmemory.h.

enum ir_entity_usage_computed_state

The state of the entity usage flags.

Definition at line 49 of file irmemory.h.

enum ir_storage_class_class_t

Classify storage locations.

Except ir_sc_pointer they are all disjoint. ir_sc_pointer potentially aliases all classes which don't have a NOTTAKEN modifier.

Enumerator:

ir_sc_pointer	generic pointer, may be anything
ir_sc_globalvar	an address of a global variable
ir_sc_localvar	an address of a local variable or method argument
ir_sc_tls	an address of a thread local storage variable
ir_sc_malloced	an allocated heap address
ir_sc_globaladdr	a constant address of something
ir_sc_modifier_nottaken	if set, the address of the variable was not taken
ir_sc_modifier_argument	if set pointer was a function argument

Definition at line 72 of file irmemory.h.

Function Documentation

void assure_irg_entity_usage_computed ( ir_graph * irg )

Assure that the entity usage flags have been computed for the given graph.

This analysis computes the entity usage state for all local variables.

Even then the information is not cleaned from the variables, call assure_irg_entity_usage_computed() again for recomputation.

void assure_irp_globals_entity_usage_computed ( void )

Assure that the address taken flag is computed for the global and TLS entities (variables).

This is an interprocedural analysis that computes the address_taken state for all global and TLS variables.

Note that this is a conservative estimation that by no Firm transformation can be invalidated, so it's only recomputed if manually triggered by calling set_irp_globals_entity_usage_state(ir_entity_usage_not_computed). Even then the information is not cleaned from the variables, call assure_irp_globals_entity_usage_computed() again for recomputation.

ir_storage_class_class_t classify_pointer	(	const ir_node *	irn,
		const ir_entity *	ent
	)

Classify a base pointer.

Parameters:

irn	the node representing the base address
ent	the base entity of the base address iff any

ir_alias_relation get_alias_relation	(	const ir_node *	adr1,
		const ir_mode *	mode1,
		const ir_node *	adr2,
		const ir_mode *	mode2
	)

Determine the alias relation between two addresses.

Parameters:

adr1	The first address.
mode1	The mode of the first memory access.
adr2	The second address.
mode2	The mode of the second memory access.

The memory disambiguator tries to determine the alias state between two memory addresses. The following rules are used:

different variable from the same segment never alias (R1 a)
variables from different segments never alias when:
- a global variable and a local one never alias (R1 b)
- a global variable and a TLS one never alias (R1 c)
- a local variable and a TLS one never alias (R1 d)
- a local variable and a parameter never alias (R1 e)
- a global variable and the result of a malloc routine never alias (R1 f)
- a local variable and the result of a malloc routine never alias (R1 g)
- a TLS variable and the result of a malloc routine never alias (R1 h)
- a parameter and the result of a malloc routine (obtained in the same routine as the parameter) never alias (R1 i)
two different variables never alias (R2)
if one is a variable whose address has never been taken there is no alias (R3)
if two memory addresses have the same base and their offsets do not describe overlapping regions there is no alias (R4)
if opt_strong_typed is set and both addresses describe entities, different types never alias (R5)

If none of these rules apply, the points-to framework must be interrogated to detect the alias relation.

ir_alias_relation get_alias_relation_ex	(	const ir_node *	adr1,
		const ir_mode *	mode1,
		const ir_node *	adr2,
		const ir_mode *	mode2
	)

Determine the alias relation between two addresses and cache the result.

Parameters:

adr1	The first address.
mode1	The mode of the first memory access.
adr2	The second address.
mode2	The mode of the second memory access.

See also:: get_alias_relation()

ir_storage_class_class_t get_base_sc ( ir_storage_class_class_t x )

Returns the base storage class (ignore modifier)

const char* get_ir_alias_relation_name ( ir_alias_relation rel )

Returns a human readable name for an alias relation.

unsigned get_irg_memory_disambiguator_options ( const ir_graph * irg )

Returns the memory disambiguator options for a graph.

Parameters:

irg the graph

ir_entity_usage_computed_state get_irp_globals_entity_usage_state ( void )

Returns the current address taken state of the globals.

void mark_private_methods ( void )

Mark all private methods, i.e.

those of which all call sites are known. We use a very convervative estimation yet: If the address of a method is never taken AND its visibility is visibility_local, then it's private.

ir_prog_pass_t* mark_private_methods_pass ( const char * name )

Creates an ir_prog pass for mark_private_methods().

Parameters:

name	the name of this pass or NULL

Returns:: the newly created ir_prog pass

void mem_disambig_init ( void )

Initialize the relation cache.

void mem_disambig_term ( void )

Free the relation cache.

void set_irg_memory_disambiguator_options	(	ir_graph *	irg,
		unsigned	options
	)

Sets the memory disambiguator options for a graph.

Parameters:

irg	the graph
options	a set of options

void set_irp_globals_entity_usage_state ( ir_entity_usage_computed_state state )

Sets the current address taken state of the globals.

Parameters:

state the new state

void set_irp_memory_disambiguator_options ( unsigned options )

Sets the global disambiguator options for all graphs not having local options.

Parameters:

options a set of options

void set_language_memory_disambiguator ( DISAMBIGUATOR_FUNC func )

Sets a source language specific memory disambiguator function.

Parameters:

func	The callback.

Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

Enumeration Type Documentation

Function Documentation