Various irnode constructors. More...

#include "firm_types.h"
#include "begin.h"
#include "irnode.h"
#include "end.h"

Functions
ir_node *	new_rd_Const_long (dbg_info db, ir_graph irg, ir_mode *mode, long value)
	Constructor for a Const node.
ir_node *	new_r_Const_long (ir_graph irg, ir_mode mode, long value)
	Constructor for a Const node.
ir_node *	new_d_Const_long (dbg_info db, ir_mode mode, long value)
ir_node *	new_Const_long (ir_mode *mode, long value)
	Make a const from a long.
ir_node *	new_rd_simpleSel (dbg_info db, ir_node block, ir_node store, ir_node objptr, ir_entity *ent)
	Constructor for a simpleSel node.
ir_node *	new_r_simpleSel (ir_node block, ir_node store, ir_node objptr, ir_entity ent)
	Constructor for a simpleSel node.
ir_node *	new_d_simpleSel (dbg_info db, ir_node store, ir_node objptr, ir_entity ent)
	Constructor for a simpleSel node.
ir_node *	new_simpleSel (ir_node store, ir_node objptr, ir_entity *ent)
	Constructor for a simpelSel node.
ir_node *	new_rd_DivRL (dbg_info db, ir_node block, ir_node memop, ir_node op1, ir_node op2, ir_mode mode, op_pin_state state)
	Constructor for a remainderless Div node.
ir_node *	new_r_DivRL (ir_node block, ir_node memop, ir_node op1, ir_node op2, ir_mode *mode, op_pin_state state)
	Constructor for a remainderless Div node.
ir_node *	new_d_DivRL (dbg_info db, ir_node memop, ir_node op1, ir_node op2, ir_mode *mode, op_pin_state state)
	Constructor for a remainderless Div node.
ir_node *	new_DivRL (ir_node memop, ir_node op1, ir_node op2, ir_mode mode, op_pin_state state)
	Constructor for a remainderless Div node.
ir_node *	new_rd_ASM (dbg_info db, ir_node block, ir_node mem, int arity, ir_node in[], ir_asm_constraint inputs, size_t n_outs, ir_asm_constraint outputs, size_t n_clobber, ident clobber[], ident asm_text)
	Constructor for an ASM pseudo node.
ir_node *	new_r_ASM (ir_node block, ir_node mem, int arity, ir_node in[], ir_asm_constraint inputs, size_t n_outs, ir_asm_constraint outputs, size_t n_clobber, ident clobber[], ident *asm_text)
	Constructor for an ASM pseudo node.
ir_node *	new_d_ASM (dbg_info db, ir_node mem, int arity, ir_node in[], ir_asm_constraint inputs, size_t n_outs, ir_asm_constraint outputs, size_t n_clobber, ident clobber[], ident *asm_text)
	Constructor for an ASM pseudo node.
ir_node *	new_ASM (ir_node mem, int arity, ir_node in[], ir_asm_constraint inputs, size_t n_outs, ir_asm_constraint outputs, size_t n_clobber, ident clobber[], ident asm_text)
	Constructor for an ASM pseudo node.
ir_graph *	get_current_ir_graph (void)
	Returns graph which is currently constructed.
void	set_current_ir_graph (ir_graph *graph)
	Sets graph which is currently constructed.
ir_node *	new_d_immBlock (dbg_info *db)
	Create an immature Block.
ir_node *	new_immBlock (void)
	Create an immature Block.
ir_node *	new_r_immBlock (ir_graph *irg)
	Create an immature Block.
ir_node *	new_rd_immBlock (dbg_info db, ir_graph irg)
	Create an immature Block.
void	add_immBlock_pred (ir_node immblock, ir_node jmp)
	Add a control flow edge to an immature block.
void	mature_immBlock (ir_node *block)
	Finalize a Block node, when all control flows are known.
void	set_cur_block (ir_node *target)
	Sets the current block in which the following constructors place the nodes they construct.
void	set_r_cur_block (ir_graph irg, ir_node target)
	Sets current block of a given graph.
ir_node *	get_cur_block (void)
	Returns the current block of the current graph.
ir_node *	get_r_cur_block (ir_graph *irg)
	Returns current block of a given graph.
ir_node *	get_value (int pos, ir_mode *mode)
	Returns the current value of a local variable.
ir_node *	get_r_value (ir_graph irg, int pos, ir_mode mode)
	Returns the current value of a local variable in given graph.
ir_mode *	ir_guess_mode (int pos)
	Try to guess the mode of a local variable.
ir_mode *	ir_r_guess_mode (ir_graph *irg, int pos)
	Try to guess the mode of a local variable in a given graph.
void	set_value (int pos, ir_node *value)
	Memorize a new definition of a variable.
void	set_r_value (ir_graph irg, int pos, ir_node value)
	Sets current value of a variable in a given graph.
ir_node *	get_store (void)
	Returns the current memory state.
ir_node *	get_r_store (ir_graph *irg)
	Returns current memory state for a given graph.
void	set_store (ir_node *store)
	Memorize a new definition of the memory state.
void	set_r_store (ir_graph irg, ir_node store)
	Sets current memory state for a given graph.
void	keep_alive (ir_node *ka)
	keep this node alive even if End is not control-reachable from it
void	irg_finalize_cons (ir_graph *irg)
	Puts the graph into state "phase_high".
void	irp_finalize_cons (void)
	Puts the program and all graphs into state phase_high.
void	ir_set_uninitialized_local_variable_func (uninitialized_local_variable_func_t *func)
	Register a new callback for the case that the value of an uninitialized variable is requested.

ir_node *	new_rd_SymConst (dbg_info db, ir_graph irg, ir_mode *mode, union symconst_symbol value, symconst_kind kind)
	addtogroup SymConst
ir_node *	new_rd_SymConst_addr_ent (dbg_info db, ir_graph irg, ir_mode mode, ir_entity symbol)
	Constructor for a SymConst addr_ent node.
ir_node *	new_rd_SymConst_ofs_ent (dbg_info db, ir_graph irg, ir_mode mode, ir_entity symbol)
	Constructor for a SymConst ofs_ent node.
ir_node *	new_rd_SymConst_size (dbg_info db, ir_graph irg, ir_mode mode, ir_type symbol)
	Constructor for a SymConst size node.
ir_node *	new_rd_SymConst_align (dbg_info db, ir_graph irg, ir_mode mode, ir_type symbol)
	Constructor for a SymConst size node.
ir_node *	new_r_SymConst (ir_graph irg, ir_mode mode, union symconst_symbol value, symconst_kind kind)
	Constructor for a SymConst node.
ir_node *	new_d_SymConst (dbg_info db, ir_mode mode, union symconst_symbol value, symconst_kind kind)
	Constructor for an SymConst node.
ir_node *	new_SymConst (ir_mode *mode, union symconst_symbol value, symconst_kind kind)
	Constructor for a SymConst node.

Variables
ir_graph *	current_ir_graph
	Global variable holding the graph which is currently constructed.

Detailed Description

Various irnode constructors.

documentation no more supported since 2001

Automatic construction of SSA representation.

Author: Martin Trapp, Christian Schaefer, Goetz Lindenmaier, Boris Boesler, Michael Beck

IR node construction.

This file documents all datatypes and constructors needed to build a FIRM representation of a procedure. The constructors are also implemented in this file.

The documentation also gives a short manual how to use the library.

For extensive documentation of FIRM see UKA Techreport 1999-14.

Three kinds of nodes

There are three kinds of nodes known to the IR: entities, types, and ir_nodes

ir_nodes are the actual nodes of the FIRM intermediate representation. They represent operations on the data of the program and control flow operations.

entity ==> implemented in entity.h Refers to a single entity of the compiled program, e.g. a field of a class or a method. If a method or variable can not be assigned to a method or class or the like, it is a global object.

types ==> implemented in type.h With types type information is represented. There are several type nodes.

Implementation of the FIRM operations: ir_node

Ir_nodes represent operations on the data of the program and control flow operations. Examples of ir_nodes: Add, Jmp, Cmp

FIRM is a dataflow graph. A dataflow graph is a directed graph, so that every node has incoming and outgoing edges. A node is executable if every input at its incoming edges is available. Execution of the dataflow graph is started at the Start node which has no incoming edges and ends when the End node executes, even if there are still executable or not executed nodes. (Is this true, or must all executable nodes be executed?) (There are exceptions to the dataflow paradigma that all inputs have to be available before a node can execute: Phi, Block. See UKA Techreport 1999-14.)

The implementation of FIRM differs from the view as a dataflow graph. To allow fast traversion of the graph edges are implemented as C-pointers. Inputs to nodes are not ambiguous, the results can be used by several other nodes. Each input can be implemented as a single pointer to a predecessor node, outputs need to be lists of pointers to successors. Therefore a node contains pointers to its predecessors so that the implementation is a dataflow graph with reversed edges. It has to be traversed bottom up.

All nodes of the IR have the same basic structure. They are distinguished by a field containing the opcode.

The fields of an ir_node:

kind A firm_kind tag containing k_ir_node. This is useful for dynamically checking the type of a node.

*op This ir_op gives the opcode as a tag and a string and the number of attributes of an ir_node. There is one statically allocated struct ir_op for each opcode.

*mode The ir_mode of the operation represented by this firm node. The mode of the operation is the mode of its result. A Firm mode is a datatype as known to the target, not a type of the source language.

visit A flag for traversing the IR.

**in An array with pointers to the node's predecessors.

*link A pointer to an ir_node. With this pointer all Phi nodes are attached to a Block, i.e. a Block points to its first Phi node, this node points to the second Phi node in the Block and so forth. Used in mature_immBlock to find all Phi nodes to be matured. It's also used to annotate a node with a better, optimized version of it.

attr An attr struct containing the attributes of the nodes. The attributes depend on the opcode of the node. The number of these attributes is given in op.

The struct ir_op

Not yet documented. See irop.h.

The struct ir_mode

Not yet documented. See irmode.h.

GLOBAL VARIABLES – now also fields of ir_graph.

current_ir_graph Points to the current ir_graph. All constructors for nodes add nodes to this graph.

ir_visited An int used as flag to traverse the ir_graph.

block_visited An int used as a flag to traverse block nodes in the graph.

Others not yet documented.

CONSTRUCTOR FOR IR_GRAPH –> see irgraph.h

PROCEDURE TO CONSTRUCT AN IR GRAPH –> see also Firm tutorial

This library supplies several interfaces to construct a FIRM graph for a program:

A "comfortable" interface generating SSA automatically. Automatically computed predecessors of nodes need not be specified in the constructors. (new_<Node> constructurs and a set of additional routines.)
A less comfortable interface where all predecessors except the block an operation belongs to need to be specified. SSA must be constructed by hand. (new_<Node> constructors and set_cur_block()). This interface is called "block oriented". It automatically calles the local optimizations for each new node.
An even less comfortable interface where the block needs to be specified explicitly. This is called the "raw" interface. (new_r_<Node> constructors). These nodes are not optimized.

To use the functionality of the comfortable interface correctly the Front End needs to follow certain protocols. This is explained in the following. To build a correct IR with the other interfaces study the semantics of the firm node (See tech-reprot UKA 1999-14). For the construction of types and entities see the documentation in those modules.

First the Frontend needs to decide which variables and values used in a procedure can be represented by dataflow edges. These are variables that need not be saved to memory as they cause no side effects visible out of the procedure. Often these are all compiler generated variables and simple local variables of the procedure as integers, reals and pointers. The frontend has to count and number these variables.

First an ir_graph needs to be constructed with new_ir_graph. The constructor gets the number of local variables. The graph is held in the global variable irg.

Now the construction of the procedure can start. Several basic blocks can be constructed in parallel, but the code within each block needs to be constructed (almost) in program order.

A global variable holds the current basic block. All (non block) nodes generated are added to this block. The current block can be set with set_cur_block(block). If several blocks are constructed in parallel block switches need to be performed constantly.

To generate a Block node (with the comfortable interface), its predecessor control flow nodes need not be known. In case of cyclic control flow these can not be known when the block is constructed. With add_immBlock_pred(block, cfnode) predecessors can be added to the block. If all predecessors are added to the block mature_immBlock(b) needs to be called. Calling mature_immBlock early improves the efficiency of the Phi node construction algorithm. But if several blocks are constructed at once, mature_immBlock must only be called after performing all set_values and set_stores in the block! (See documentation of new_immBlock constructor.)

The constructors of arithmetic nodes require that their predecessors are mentioned. Sometimes these are available in the Frontend as the predecessors have just been generated by the frontend. If they are local values, the predecessors can be obtained from the library with a call to get_value(local_val_nr). (local_val_nr needs to be administered by the Frontend.) A call to get_value triggers the generation of Phi nodes. If an arithmetic operation produces a local value, this value needs to be passed to the library by set_value(node, local_val_nr). In straight line code these two operations just remember and return the pointer to nodes producing the value. If the value passes block boundaries Phi nodes can be inserted. Similar routines exist to manage the Memory operands: set_store and get_store.

Several nodes produce more than one result. An example is the Div node. Such nodes return tuples of values. From these individual values can be extracted by proj nodes.

The following example illustrates the construction of a simple basic block with two predecessors stored in variables cf_pred1 and cf_pred2, containing the code a = a div a; and finally jumping to an other block. The variable a got the local_val_nr 42 by the frontend.

ir_node *this_block, *cf_pred1, *cf_pred2, *a_val, *mem, *div, *res, *cf_op;

this_block = new_immBlock(); add_immBlock_pred(this_block, cf_pred1); add_immBlock_pred(this_block, cf_pred2); mature_immBlock(this_block); a_val = get_value(42, mode_Iu); mem = get_store(); div = new_Div(mem, a_val, a_val, mode_Iu); mem = new_Proj(div, mode_M, pn_Div_M); * for the numbers for Proj see docu * res = new_Proj(div, mode_Iu, pn_Div_res); set_store(mem); set_value(res, 42); cf_op = new_Jmp();

For further information look at the documentation of the nodes and constructors and at the paragraph COPING WITH DATA OBJECTS at the end of this documentation.

IR_NODES AND CONSTRUCTORS FOR IR_NODES

All ir_nodes are defined by a common data structure. They are distinguished by their opcode and differ in the number of their attributes.

Const nodes are always added to the start block. All other constructors add the created node to the current_block. swich_block(block) allows to set the current block to block.

Watch for my inconsistent use of input and predecessor (dataflow view) and `the node points to' (implementation view).

The following description of the nodes lists four properties them if these are of interest:

the parameters to the constructor
the inputs of the Firm node
the outputs of the Firm node
attributes to the node

COPING WITH DATA OBJECTS

Two kinds of data objects have to be distinguished for generating FIRM. First there are local variables other than arrays that are known to be alias free. Second there are all other data objects. For the first a common SSA representation is built, the second are modeled by saving them to memory. The memory is treated as a single local variable, the alias problem is hidden in the content of this variable.

All values known in a Block are listed in the block's attribute, block.**graph_arr which is used to automatically insert Phi nodes. The following two functions can be used to add a newly computed value to the array, or to get the producer of a value, i.e., the current live value.

inline void set_value (int pos, ir_node *value)

Has to be called for every assignment to a local variable. It adds the value to the array of used values at position pos. Pos has to be a unique identifier for an entry in the procedure's definition table. It can be used to access the value again. Requires current_block to be set correctly.

ir_node get_value (int pos, ir_mode mode)

Returns the node defining the value referred to by pos. If the value is not defined in this block a Phi node is generated and all definitions reaching this Phi node are collected. It can happen that the algorithm allocates an unnecessary Phi node, e.g. if there is only one definition of this value, but this definition reaches the currend block on several different paths. This Phi node will be eliminated if optimizations are turned on right after its creation. Requires current_block to be set correctly.

There are two special routines for the global store:

Definition in file ircons.h.

Function Documentation

ir_node* new_d_SymConst	(	dbg_info *	db,
		ir_mode *	mode,
		union symconst_symbol	value,
		symconst_kind	kind
	)

Constructor for an SymConst node.

This is the constructor for a symbolic constant. There are several kinds of symbolic constants:

symconst_type_size The symbolic constant represents the size of a type. The type of which the constant represents the size is given explicitly.
symconst_type_align The symbolic constant represents the alignment of a type. The type of which the constant represents the size is given explicitly.
symconst_addr_ent The symbolic constant represents the address of an entity (variable or method). The variable is given explicitly by a firm entity.
symconst_ofs_ent The symbolic constant represents the offset of an entity in its owner type.
symconst_enum_const The symbolic constant is a enumeration constant of an enumeration type.

Inputs to the node: No inputs except the block it belongs to. Outputs of the node. An unsigned integer (I_u) or a pointer (P).

Mention union in declaration so that the firmjni generator recognizes that it can not cast the argument to an int.

Parameters

*db	A pointer for debug information.
mode	The mode for the SymConst.
value	A type, ident, entity or enum constant depending on the SymConst kind.
kind	The kind of the symbolic constant, see the list above

ir_node* new_r_SymConst	(	ir_graph *	irg,
		ir_mode *	mode,
		union symconst_symbol	value,
		symconst_kind	kind
	)

Constructor for a SymConst node.

This is the constructor for a symbolic constant. There are several kinds of symbolic constants:

symconst_type_size The symbolic constant represents the size of a type. The type of which the constant represents the size is given explicitly.
symconst_type_align The symbolic constant represents the alignment of a type. The type of which the constant represents the size is given explicitly.
symconst_addr_ent The symbolic constant represents the address of an entity (variable or method). The variable is given explicitly by a firm entity.
symconst_ofs_ent The symbolic constant represents the offset of an entity in its owner type.
symconst_enum_const The symbolic constant is a enumeration constant of an enumeration type.

Inputs to the node: No inputs except the block it belongs to. Outputs of the node. An unsigned integer (I_u) or a pointer (P).

Mention union in declaration so that the firmjni generator recognizes that it can not cast the argument to an int.

Parameters

*irg	The IR graph the node belongs to.
mode	The mode for the SymConst.
value	A type, ident, entity or enum constant depending on the SymConst kind.
kind	The kind of the symbolic constant, see the list above

ir_node* new_rd_SymConst	(	dbg_info *	db,
		ir_graph *	irg,
		ir_mode *	mode,
		union symconst_symbol	value,
		symconst_kind	kind
	)

addtogroup SymConst

Constructor for a SymConst node.

This is the constructor for a symbolic constant. There are several kinds of symbolic constants:

symconst_type_size The symbolic constant represents the size of a type. The type of which the constant represents the size is given explicitly.
symconst_type_align The symbolic constant represents the alignment of a type. The type of which the constant represents the size is given explicitly.
symconst_addr_ent The symbolic constant represents the address of an entity (variable or method). The variable is given explicitly by a firm entity.
symconst_ofs_ent The symbolic constant represents the offset of an entity in its owner type.
symconst_enum_const The symbolic constant is a enumeration constant of an enumeration type.

Inputs to the node: No inputs except the block it belongs to. Outputs of the node. An unsigned integer (I_u) or a pointer (P).

Mention union in declaration so that the firmjni generator recognizes that it can not cast the argument to an int.

Parameters

*db	A pointer for debug information.
*irg	The IR graph the node belongs to.
mode	The mode for the SymConst.
value	A type, ident, entity or enum constant depending on the SymConst kind.
kind	The kind of the symbolic constant, see the list above

ir_node* new_rd_SymConst_addr_ent	(	dbg_info *	db,
		ir_graph *	irg,
		ir_mode *	mode,
		ir_entity *	symbol
	)

Constructor for a SymConst addr_ent node.

Same as new_rd_SymConst, except that the constructor is tailored for symconst_addr_ent. Adds the SymConst to the start block of irg.

ir_node* new_rd_SymConst_align	(	dbg_info *	db,
		ir_graph *	irg,
		ir_mode *	mode,
		ir_type *	symbol
	)

Constructor for a SymConst size node.

Same as new_rd_SymConst, except that the constructor is tailored for symconst_type_align. Adds the SymConst to the start block of irg.

ir_node* new_rd_SymConst_ofs_ent	(	dbg_info *	db,
		ir_graph *	irg,
		ir_mode *	mode,
		ir_entity *	symbol
	)

Constructor for a SymConst ofs_ent node.

Same as new_rd_SymConst, except that the constructor is tailored for symconst_ofs_ent. Adds the SymConst to the start block of irg.

ir_node* new_rd_SymConst_size	(	dbg_info *	db,
		ir_graph *	irg,
		ir_mode *	mode,
		ir_type *	symbol
	)

Constructor for a SymConst size node.

Same as new_rd_SymConst, except that the constructor is tailored for symconst_type_size. Adds the SymConst to the start block of irg.

ir_node* new_SymConst	(	ir_mode *	mode,
		union symconst_symbol	value,
		symconst_kind	kind
	)

Constructor for a SymConst node.

This is the constructor for a symbolic constant. There are several kinds of symbolic constants:

symconst_type_size The symbolic constant represents the size of a type. The type of which the constant represents the size is given explicitly.
symconst_type_align The symbolic constant represents the alignment of a type. The type of which the constant represents the size is given explicitly.
symconst_addr_ent The symbolic constant represents the address of an entity (variable or method). The variable is given explicitly by a firm entity.
symconst_ofs_ent The symbolic constant represents the offset of an entity in its owner type.
symconst_enum_const The symbolic constant is a enumeration constant of an enumeration type.

Inputs to the node: No inputs except the block it belongs to. Outputs of the node. An unsigned integer (I_u) or a pointer (P).

Mention union in declaration so that the firmjni generator recognizes that it can not cast the argument to an int.

Parameters

mode	The mode for the SymConst.
value	A type, ident, entity or enum constant depending on the SymConst kind.
kind	The kind of the symbolic constant, see the list above

Functions

Variables

Detailed Description

Three kinds of nodes

Implementation of the FIRM operations: ir_node

The struct ir_op

The struct ir_mode

GLOBAL VARIABLES – now also fields of ir_graph.

CONSTRUCTOR FOR IR_GRAPH –> see irgraph.h

PROCEDURE TO CONSTRUCT AN IR GRAPH –> see also Firm tutorial

IR_NODES AND CONSTRUCTORS FOR IR_NODES

COPING WITH DATA OBJECTS

inline void set_value (int pos, ir_node *value)

ir_node *get_value (int pos, ir_mode *mode)

Function Documentation

ir_node get_value (int pos, ir_mode mode)