Lowering is the process of transforming a highlevel representation (a representation closer to the sourcecode) into a lower-level representation (something closer to the target machine). More...

Data Structures
struct	i_call_record
	An intrinsic call record. More...

struct	i_instr_record
	An intrinsic instruction record. More...

union	i_record
	An intrinsic record. More...

Typedefs
typedef int	lower_mux_callback (ir_node *mux)
	Used as callback, whenever a lowerable mux is found. More...

typedef int(	i_mapper_func )(ir_node *node)
	An intrinsic mapper function. More...

typedef struct ir_intrinsics_map	ir_intrinsics_map

Enumerations
enum	ikind { INTRINSIC_CALL = 0, INTRINSIC_INSTR }
	kind of an instruction record More...

Functions
void	lower_CopyB (ir_graph *irg, unsigned max_small_size, unsigned min_large_size, int allow_misalignments)
	Lower small CopyB nodes to Load/Store nodes, preserve medium-sized CopyB nodes and replace large CopyBs by a call to memcpy, depending on the given parameters. More...

void	lower_switch (ir_graph irg, unsigned small_switch, unsigned spare_size, ir_mode selector_mode)
	Lowers all Switches (Cond nodes with non-boolean mode) depending on spare_size. More...

void	lower_highlevel_graph (ir_graph *irg)
	Replaces Offsets and TypeConsts by a real constant if possible. More...

void	lower_highlevel (void)
	Replaces Offsets and TypeConsts by a real constant if possible. More...

void	lower_const_code (void)
	does the same as lower_highlevel for all nodes on the const code irg More...

void	lower_mux (ir_graph irg, lower_mux_callback cb_func)
	Lowers all mux nodes in the given graph. More...

ir_intrinsics_map *	ir_create_intrinsics_map (i_record *list, size_t length, int part_block_used)
	Create a new intrinsic lowering map which can be used by ir_lower_intrinsics. More...

void	ir_free_intrinsics_map (ir_intrinsics_map *map)
	Frees resources occupied by an intrisics_map created by ir_create_intrinsics_map(). More...

void	ir_lower_intrinsics (ir_graph irg, ir_intrinsics_map map)
	Go through all graphs and map calls to intrinsic functions and instructions. More...

int	i_mapper_abs (ir_node *call)
	A mapper for the integer/float absolute value: type abs(type v). More...

int	i_mapper_sqrt (ir_node *call)
	A mapper for the floating point sqrt(v): floattype sqrt(floattype v);. More...

int	i_mapper_cbrt (ir_node *call)
	A mapper for the floating point cbrt(v): floattype sqrt(floattype v);. More...

int	i_mapper_pow (ir_node *call)
	A mapper for the floating point pow(a, b): floattype pow(floattype a, floattype b);. More...

int	i_mapper_exp (ir_node *call)
	A mapper for the floating point exp(a): floattype exp(floattype a);. More...

int	i_mapper_exp2 (ir_node *call)
	A mapper for the floating point exp2(a): floattype exp2(floattype a);. More...

int	i_mapper_exp10 (ir_node *call)
	A mapper for the floating point exp10(a): floattype exp10(floattype a);. More...

int	i_mapper_log (ir_node *call)
	A mapper for the floating point log(a): floattype log(floattype a);. More...

int	i_mapper_log2 (ir_node *call)
	A mapper for the floating point log(a): floattype log(floattype a);. More...

int	i_mapper_log10 (ir_node *call)
	A mapper for the floating point log(a): floattype log(floattype a);. More...

int	i_mapper_sin (ir_node *call)
	A mapper for the floating point sin(a): floattype sin(floattype a);. More...

int	i_mapper_cos (ir_node *call)
	A mapper for the floating point sin(a): floattype cos(floattype a);. More...

int	i_mapper_tan (ir_node *call)
	A mapper for the floating point tan(a): floattype tan(floattype a);. More...

int	i_mapper_asin (ir_node *call)
	A mapper for the floating point asin(a): floattype asin(floattype a);. More...

int	i_mapper_acos (ir_node *call)
	A mapper for the floating point acos(a): floattype acos(floattype a);. More...

int	i_mapper_atan (ir_node *call)
	A mapper for the floating point atan(a): floattype atan(floattype a);. More...

int	i_mapper_sinh (ir_node *call)
	A mapper for the floating point sinh(a): floattype sinh(floattype a);. More...

int	i_mapper_cosh (ir_node *call)
	A mapper for the floating point cosh(a): floattype cosh(floattype a);. More...

int	i_mapper_tanh (ir_node *call)
	A mapper for the floating point tanh(a): floattype tanh(floattype a);. More...

int	i_mapper_strcmp (ir_node *call)
	A mapper for the strcmp-Function: inttype strcmp(char pointer a, char pointer b);. More...

int	i_mapper_strncmp (ir_node *call)
	A mapper for the strncmp-Function: inttype strncmp(char pointer a, char pointer b, inttype len);. More...

int	i_mapper_strcpy (ir_node *call)
	A mapper for the strcpy-Function: char pointer strcpy(char pointer a, char pointer b);. More...

int	i_mapper_strlen (ir_node *call)
	A mapper for the strlen-Function: inttype strlen(char pointer a);. More...

int	i_mapper_memcpy (ir_node *call)
	A mapper for the memcpy-Function: void pointer memcpy(void pointer d, void pointer s, inttype c);. More...

int	i_mapper_memmove (ir_node *call)
	A mapper for the memmove-Function: void pointer memmove(void pointer d, void pointer s, inttype c);. More...

int	i_mapper_memset (ir_node *call)
	A mapper for the memset-Function: void pointer memset(void pointer d, inttype C, inttype len);. More...

int	i_mapper_memcmp (ir_node *call)
	A mapper for the strncmp-Function: inttype memcmp(void pointer a, void pointer b, inttype len);. More...

Detailed Description

Lowering is the process of transforming a highlevel representation (a representation closer to the sourcecode) into a lower-level representation (something closer to the target machine).

Data Structure Documentation

struct i_call_record

An intrinsic call record.

Definition at line 160 of file lowering.h.

Data Fields
ir_entity *	i_ent	the entity representing an intrinsic call
i_mapper_func *	i_mapper	the mapper function to call
enum ikind	kind	must be INTRINSIC_CALL

struct i_instr_record

An intrinsic instruction record.

Definition at line 169 of file lowering.h.

Data Fields
i_mapper_func *	i_mapper	the mapper function to call
enum ikind	kind	must be INTRINSIC_INSTR
ir_op *	op	the opcode that must be mapped.

union i_record

An intrinsic record.

Definition at line 178 of file lowering.h.

Data Fields
i_call_record	i_call	used for call records
i_instr_record	i_instr	used for isnstruction records
enum ikind	kind	kind of record

Typedef Documentation

typedef int( i_mapper_func)(ir_node *node)

An intrinsic mapper function.

Parameters

node	the IR-node that will be mapped

Returns: non-zero if the call was mapped

Definition at line 148 of file lowering.h.

typedef struct ir_intrinsics_map ir_intrinsics_map

Definition at line 184 of file lowering.h.

typedef int lower_mux_callback(ir_node *mux)

Used as callback, whenever a lowerable mux is found.

The return value indicates, whether the mux should be lowered. This may be used, to lower floating point muxes, while keeping mux nodes for integers, for example.

Parameters

mux	The mux node that may be lowered.

Returns: A non-zero value indicates that the mux should be lowered.

Definition at line 130 of file lowering.h.

Enumeration Type Documentation

enum ikind

kind of an instruction record

See Also: i_record

Enumerator
INTRINSIC_CALL	the record represents an intrinsic call
INTRINSIC_INSTR	the record represents an intrinsic instruction

Definition at line 152 of file lowering.h.

Function Documentation

int i_mapper_abs ( ir_node * call )

A mapper for the integer/float absolute value: type abs(type v).

Replaces the call by a Abs node.

Returns: always 1

int i_mapper_acos ( ir_node * call )

A mapper for the floating point acos(a): floattype acos(floattype a);.

Returns: 1 if the tan call was removed, 0 else.

int i_mapper_asin ( ir_node * call )

A mapper for the floating point asin(a): floattype asin(floattype a);.

Returns: 1 if the asin call was removed, 0 else.

int i_mapper_atan ( ir_node * call )

A mapper for the floating point atan(a): floattype atan(floattype a);.

Returns: 1 if the atan call was removed, 0 else.

int i_mapper_cbrt ( ir_node * call )

A mapper for the floating point cbrt(v): floattype sqrt(floattype v);.

Returns: 1 if the cbrt call was removed, 0 else.

int i_mapper_cos ( ir_node * call )

A mapper for the floating point sin(a): floattype cos(floattype a);.

Returns: 1 if the cos call was removed, 0 else.

int i_mapper_cosh ( ir_node * call )

A mapper for the floating point cosh(a): floattype cosh(floattype a);.

Returns: 1 if the cosh call was removed, 0 else.

int i_mapper_exp ( ir_node * call )

A mapper for the floating point exp(a): floattype exp(floattype a);.

Returns: 1 if the exp call was removed, 0 else.

int i_mapper_exp10 ( ir_node * call )

A mapper for the floating point exp10(a): floattype exp10(floattype a);.

Returns: 1 if the exp call was removed, 0 else.

int i_mapper_exp2 ( ir_node * call )

A mapper for the floating point exp2(a): floattype exp2(floattype a);.

Returns: 1 if the exp call was removed, 0 else.

int i_mapper_log ( ir_node * call )

A mapper for the floating point log(a): floattype log(floattype a);.

Returns: 1 if the log call was removed, 0 else.

int i_mapper_log10 ( ir_node * call )

A mapper for the floating point log(a): floattype log(floattype a);.

Returns: 1 if the log call was removed, 0 else.

int i_mapper_log2 ( ir_node * call )

A mapper for the floating point log(a): floattype log(floattype a);.

Returns: 1 if the log call was removed, 0 else.

int i_mapper_memcmp ( ir_node * call )

A mapper for the strncmp-Function: inttype memcmp(void pointer a, void pointer b, inttype len);.

Returns: 1 if the strncmp call was removed, 0 else.

int i_mapper_memcpy ( ir_node * call )

A mapper for the memcpy-Function: void pointer memcpy(void pointer d, void pointer s, inttype c);.

Returns: 1 if the memcpy call was removed, 0 else.

int i_mapper_memmove ( ir_node * call )

A mapper for the memmove-Function: void pointer memmove(void pointer d, void pointer s, inttype c);.

Returns: 1 if the memmove call was removed, 0 else.

int i_mapper_memset ( ir_node * call )

A mapper for the memset-Function: void pointer memset(void pointer d, inttype C, inttype len);.

Returns: 1 if the memset call was removed, 0 else.

int i_mapper_pow ( ir_node * call )

A mapper for the floating point pow(a, b): floattype pow(floattype a, floattype b);.

Returns: 1 if the pow call was removed, 0 else.

int i_mapper_sin ( ir_node * call )

A mapper for the floating point sin(a): floattype sin(floattype a);.

Returns: 1 if the sin call was removed, 0 else.

int i_mapper_sinh ( ir_node * call )

A mapper for the floating point sinh(a): floattype sinh(floattype a);.

Returns: 1 if the sinh call was removed, 0 else.

int i_mapper_sqrt ( ir_node * call )

A mapper for the floating point sqrt(v): floattype sqrt(floattype v);.

Returns: 1 if the sqrt call was removed, 0 else.

int i_mapper_strcmp ( ir_node * call )

A mapper for the strcmp-Function: inttype strcmp(char pointer a, char pointer b);.

Returns: 1 if the strcmp call was removed, 0 else.

int i_mapper_strcpy ( ir_node * call )

A mapper for the strcpy-Function: char pointer strcpy(char pointer a, char pointer b);.

Returns: 1 if the strcpy call was removed, 0 else.

int i_mapper_strlen ( ir_node * call )

A mapper for the strlen-Function: inttype strlen(char pointer a);.

Returns: 1 if the strlen call was removed, 0 else.

int i_mapper_strncmp ( ir_node * call )

A mapper for the strncmp-Function: inttype strncmp(char pointer a, char pointer b, inttype len);.

Returns: 1 if the strncmp call was removed, 0 else.

int i_mapper_tan ( ir_node * call )

A mapper for the floating point tan(a): floattype tan(floattype a);.

Returns: 1 if the tan call was removed, 0 else.

int i_mapper_tanh ( ir_node * call )

A mapper for the floating point tanh(a): floattype tanh(floattype a);.

Returns: 1 if the tanh call was removed, 0 else.

ir_intrinsics_map* ir_create_intrinsics_map	(	i_record *	list,
		size_t	length,
		int	part_block_used
	)

Create a new intrinsic lowering map which can be used by ir_lower_intrinsics.

Parameters

list	an array of intrinsic map records
length	the length of the array
part_block_used	set to 1 if part_block() is used by one of the lowering functions.

void ir_free_intrinsics_map ( ir_intrinsics_map * map )

Frees resources occupied by an intrisics_map created by ir_create_intrinsics_map().

void ir_lower_intrinsics	(	ir_graph *	irg,
		ir_intrinsics_map *	map
	)

Go through all graphs and map calls to intrinsic functions and instructions.

Every call or instruction is reported to its mapper function, which is responsible for rebuilding the graph.

void lower_const_code ( void )

does the same as lower_highlevel for all nodes on the const code irg

void lower_CopyB	(	ir_graph *	irg,
		unsigned	max_small_size,
		unsigned	min_large_size,
		int	allow_misalignments
	)

Lower small CopyB nodes to Load/Store nodes, preserve medium-sized CopyB nodes and replace large CopyBs by a call to memcpy, depending on the given parameters.

Every CopyB is assigned a size category as follows:

'small' iff size <= max_small_size,
'medium' iff max_small_size < size < min_large_size,
'large' iff size >= min_large_size.

The idea is that each backend can apply different optimizations in each of the three categories.

For small CopyBs, the x86 backend could, e.g., emit a single SSE instruction to copy 16 bytes. Other backends might just go with a series of Load/Stores. Therefore, x86 would like to keep the small CopyB nodes around whereas other backends would not. For medium-sized CopyBs, the x86 backend might generate a rep-prefixed mov instruction. Hence, it also wants to keep the CopyBs in these cases. Other backends might handle this differently. For large CopyBs, a call to memcpy is worth the call overhead, so large CopyBs should always be lowered to memcpy calls.

The lowerer performs the following actions if the CopyB is

'small': Replace it with a series of Loads/Stores
'medium': Nothing.
'large': Replace it with a call to memcpy.

max_small_size and min_large_size allow for a flexible configuration. For example, one backend could specify max_small_size == 0 and min_large_size == 8192 to keep all CopyB nodes smaller than 8192 and get memcpy Calls for all others. Here, the set of small CopyBs is empty. Another backend could specify max_small_size == 63 and min_large_size == 64 to lower all small CopyBs to Loads/Stores and all big CopyBs to memcpy. Hence, the set of medium-sized CopyBs is empty and this backend never sees a CopyB node at all. If memcpy is not available, min_large_size can be set to UINT_MAX to prevent the creation of calls to memcpy. Note that CopyBs whose size is UINT_MAX will still be lowered to memcpy calls because we check if the size is greater or equal to min_large_size. However, this should never occur in practice.

Parameters

irg	The graph to be lowered.
max_small_size	The maximum number of bytes for a CopyB node so that it is still considered 'small'.
min_large_size	The minimum number of bytes for a CopyB node so that it is regarded as 'large'.
allow_misalignments	Backend can handle misaligned loads and stores.

void lower_highlevel ( void )

Replaces Offsets and TypeConsts by a real constant if possible.

Replaces Sel nodes by address computation. Also resolves array access. Handle bit fields by added And/Or calculations. Lowers all graphs.

Note: There is NO lowering of objects oriented types. This is highly compiler and ABI specific and should be placed directly in the compiler.

void lower_highlevel_graph ( ir_graph * irg )

Replaces Offsets and TypeConsts by a real constant if possible.

Replaces Sel nodes by address computation. Also resolves array access. Handle bit fields by added And/Or calculations.

Parameters

irg	the graph to lower

Note: : There is NO lowering ob objects oriented types. This is highly compiler and ABI specific and should be placed directly in the compiler.

void lower_mux	(	ir_graph *	irg,
		lower_mux_callback *	cb_func
	)

Lowers all mux nodes in the given graph.

A callback function may be given, to select the mux nodes to lower.

Parameters

irg	The graph to lower mux nodes in.
cb_func	The callback function for mux selection. Can be NULL, to lower all mux nodes.

void lower_switch	(	ir_graph *	irg,
		unsigned	small_switch,
		unsigned	spare_size,
		ir_mode *	selector_mode
	)

Lowers all Switches (Cond nodes with non-boolean mode) depending on spare_size.

They will either remain the same or be converted into if-cascades.

Parameters

irg	The ir graph to be lowered.
small_switch	If switch has <= cases then change it to an if-cascade.
spare_size	Allowed spare size for table switches in machine words. (Default in edgfe: 128)
selector_mode	mode which must be used for Switch selector

Data Structures

Typedefs

Enumerations

Functions

Detailed Description

Data Structure Documentation

Typedef Documentation

Enumeration Type Documentation

Function Documentation