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exprNode Class Reference
[The AST nodes]

Expression node. More...

#include <ast.h>

Inheritance diagram for exprNode:

Node binaryNode callNode castNode commaNode indexNode initializerNode metaexprNode operandNode ternaryNode unaryNode List of all members.

Garbage collection.

bool mark
static node_list nodes
static map< Node *, bool > deleted_nodes

Public Member Functions

 exprNode (NodeType typ, typeNode *type, const Coord coord)
 Create a new expression node.
virtual ~exprNode ()
 Destroy a exprNode.
virtual typeNodebase_type (bool TdefIndir) const
 Return the base data type of a node.
virtual void eval ()=0
 Constant expression evaluator.
virtual bool is_lvalue ()
 Is l-value.
typeNodeno_tdef_type ()
virtual void output (output_context &ct, Node *par)
 Generate C code.
virtual void output_expr (output_context &ct, Node *par, int prec, Assoc assoc)=0
 Output a expression.
virtual int precedence (Assoc &assoc)
 Associativity and precedence.
bool parens (int outer_prec, Assoc outer_assoc)
 Determine if parenthesis are needed.
typeNodedatatype () const
 Call base_type() with the argument true.
typeNodedatatype_superior () const
 Call base_type() with the argument false.
virtual void dataflow (FlowVal *v, FlowProblem &fp)=0
 Run the dataflow analyzer.
virtual Nodeclone () const =0
 Clone the input node.
Accessors
Methods to get and set fields in the class.

virtual typeNodetype () const
 Return the node data type.
typeNodeget_type ()
virtual void type (typeNode *type)
const constantvalue () const
constantvalue ()
void value (const constant &newval)
Accessors
Methods to get and set fields in the class.

NodeType typ () const
 Get the node type.
Coord coord () const
 Get the source location.
void coord (const Coord coord)
 Set the source location.
bool parenthesized () const
 Get the parenthesized boolean.
void parenthesized (bool paren)
 Set the parenthesized boolean.
annote_listannotations ()
 Get the annotations list.
FlowValgen () const
 Get the "gen" flow value.
void gen (FlowVal *g)
 Set the "gen" flow value.
FlowValkill () const
 Get the "kill" flow value.
void kill (FlowVal *k)
 Set the "kill" flow value.
AST traversal
These methods provide a uniform way to traverse the AST without explicitly testing the node types. They are all variations of the visitor design pattern. The input object is an instance of a user-defined subclass of Visitor, Walker or Changer. By overriding virtual methods, the user can define what to do at each kind of node that is encountered. See the C-Breeze documentation for more details.

virtual void visit (Visitor *the_visitor)=0
 Dispatch a Visitor.
virtual void walk (Walker &the_walker)=0
 Dispatch a Walker.
virtual Nodechange (Changer &the_changer, bool redispatch=false)=0
 Dispatch a Changer.

Static Public Member Functions

static exprNodeintegral_promotions (exprNode *old_expr)
 Add integral promotions.
static pair< exprNode *, exprNode * > usual_arithmetic_conversions (exprNode *left, exprNode *right)
 Usual arithmetic conversions.
static void report ()
 Report node count statistics.

Private Attributes

TREE typeNode_type
 the type of the expression
constant _value
 the value of the expression

Detailed Description

Expression node.

This class rovides a base class for all expression nodes. It contains two fields that all expressions have: a type and a value. Initially, both fields are empty, with two exceptions. Constant expression have their values set, and the cast expressions have their type set. We can compute these values for any expression subtree using the appropriate facility. To compute the type of intermediate expressions, use the semcheck_walker. To compute the values of constant expressions, call the eval() method.

The NodeType depends on the specific exprNode subclass.

See also:
semcheck_walker

Definition at line 3099 of file ast.h.


Constructor & Destructor Documentation

exprNode::exprNode NodeType  typ,
typeNode type,
const Coord  coord
 

Create a new expression node.

This constructor is only called directly by the exprNode subclasses. The NodeType is determined by the subclass.

Parameters:
typ the kind of expression node
type the type of the expression (only for casts) or null
coord the location of the construct in the source file.

virtual exprNode::~exprNode  )  [virtual]
 

Destroy a exprNode.

Warning:
Do not use the destructors to delete AST nodes. Instead, rely on the node garbage collector.


Member Function Documentation

annote_list& Node::annotations  )  [inline, inherited]
 

Get the annotations list.

This method returns a modifiable reference to the list of annotations on the node. Users can add new annotations, search for annotations, or remove annotations. Users are responsible for ensuring that every element of the annotation list points to a valid annotation. In particular, no element should be NULL.

See also:
Annote class

Definition at line 274 of file ast.h.

References Node::_annotations.

virtual typeNode* exprNode::base_type bool  TdefIndir  )  const [virtual]
 

Return the base data type of a node.

This method differs from the Node::type() method in two respects. First, it follows some of the simple type inferences. For example, calling it on an idNode will return the type of its declaration. Second, the boolean argument indicates whether or not to follow typedef links.

Parameters:
TdefIndir pass true to follow typedefs to their definitions.

Reimplemented from Node.

Reimplemented in idNode, commaNode, and callNode.

virtual Node* Node::change Changer the_changer,
bool  redispatch = false
[pure virtual, inherited]
 

Dispatch a Changer.

This abstract method works much the walker, but allows the tree to be changed.

Parameters:
the_changer the specific Changer object to use.
redispatch pass true to revisit parts of the tree that have changed.

Implemented in unitNode, declNode, subdeclNode, procNode, primNode, tdefNode, ptrNode, arrayNode, funcNode, structNode, unionNode, enumNode, suespecNode, constNode, idNode, binaryNode, unaryNode, castNode, commaNode, ternaryNode, callNode, initializerNode, blockNode, basicblockNode, exprstmtNode, labelNode, caseNode, ifNode, switchNode, whileNode, doNode, forNode, gotoNode, continueNode, breakNode, returnNode, attribNode, operandNode, conditiongotoNode, threeAddrNode, textNode, metaexprNode, and metastmtNode.

virtual Node* Node::clone  )  const [pure virtual, inherited]
 

Clone the input node.

This is not a "deep" clone, so be careful. For a deep clone, use the ref_clone_changer class.

Returns:
a shallow copy of the node (no subtrees are copied).

Implemented in unitNode, declNode, subdeclNode, procNode, primNode, tdefNode, ptrNode, arrayNode, funcNode, structNode, unionNode, enumNode, suespecNode, constNode, idNode, binaryNode, unaryNode, castNode, commaNode, ternaryNode, callNode, initializerNode, blockNode, basicblockNode, exprstmtNode, labelNode, caseNode, ifNode, switchNode, whileNode, doNode, forNode, gotoNode, continueNode, breakNode, returnNode, attribNode, operandNode, conditiongotoNode, threeAddrNode, textNode, metaexprNode, and metastmtNode.

Referenced by ref_clone_changer::at_node().

void Node::coord const Coord  coord  )  [inline, inherited]
 

Set the source location.

This location should indicate the position in the source text that this Node represents, or Coord::Unknown if it does not represent any node in the source text.

It is not common to set the source location of a node. Currently, only the compiler error messages actually make use of it.

Parameters:
coord the new location.

Definition at line 243 of file ast.h.

References Node::_coord.

Coord Node::coord  )  const [inline, inherited]
 

Get the source location.

The Coord class holds a location in the input source (file, line, position). During parsing, each AST node created records the position of the source text that it represents. However, subsequent phases may create or change nodes, so no guarantee is given about how the source location corresponds to the original source text.

Returns:
the Coord structure indicating where the node came from in the source file.

Definition at line 230 of file ast.h.

References Node::_coord.

virtual void Node::dataflow FlowVal v,
FlowProblem fp
[pure virtual, inherited]
 

Run the dataflow analyzer.

Each subclass overrides this method to define it's semantics for dataflow analysis. It alters the input flow value to reflect the effect of the node within the given flow problem, calling dataflow() on it's subtrees as necessary. See the dataflow analysis documentation for more information.

Parameters:
v the flow value to pass through the node.
fp the flow problem (specifying the transfer functions).

Implemented in unitNode, declNode, procNode, typeNode, constNode, idNode, binaryNode, unaryNode, castNode, commaNode, ternaryNode, callNode, initializerNode, blockNode, exprstmtNode, labelNode, caseNode, ifNode, switchNode, whileNode, doNode, forNode, gotoNode, continueNode, breakNode, returnNode, attribNode, operandNode, conditiongotoNode, threeAddrNode, textNode, metaexprNode, and metastmtNode.

typeNode* Node::datatype  )  const [inherited]
 

Call base_type() with the argument true.

typeNode* Node::datatype_superior  )  const [inherited]
 

Call base_type() with the argument false.

virtual void exprNode::eval  )  [pure virtual]
 

Constant expression evaluator.

This method attempts to evaluate an expression at compile-time. This only yields a meaningful value when the leaves of the given expression are constants, enums, or other compile-time values (e.g., sizeof). The resulting value is stored on each exprNode, in the _value field. Each exprNode sublcass implements this method, calling it recursively when necessary.

Implemented in constNode, idNode, binaryNode, unaryNode, castNode, commaNode, ternaryNode, callNode, initializerNode, operandNode, and metaexprNode.

void Node::gen FlowVal g  )  [inline, inherited]
 

Set the "gen" flow value.

This value is used in dataflow analyses to store information that is generated at this node. Note that each node has exactly one "gen" flow value.

In order to set the flow value to be empty, call this method with a value of NULL.

Parameters:
g the new gen flow value.

Definition at line 297 of file ast.h.

References Node::_gen.

FlowVal* Node::gen  )  const [inline, inherited]
 

Get the "gen" flow value.

This value is used in dataflow analyses to store information that is generated at this node. Note that each node has exactly one "gen" flow value.

Returns:
the "gen" flow value.

Definition at line 284 of file ast.h.

References Node::_gen.

typeNode* exprNode::get_type  )  [inline]
 

Definition at line 3178 of file ast.h.

References _type.

static exprNode* exprNode::integral_promotions exprNode old_expr  )  [static]
 

Add integral promotions.

This method takes an expression and calls typeNode::integral_promotions() on its type to determine if any apply. If they do, it inserts an implicit castNode above the input expression that represents this implicit conversion.

See also:
castNode
Parameters:
old_expr the expression to perform integral promotion on
Returns:
the resulting expression, with a cast added if necessary

virtual bool exprNode::is_lvalue  )  [inline, virtual]
 

Is l-value.

Indicates if the expression is an l-value (that is, the left side of an assignment).

Todo:
This doesn't work yet.
Returns:
true if the given expression is an l-value

Definition at line 3224 of file ast.h.

void Node::kill FlowVal k  )  [inline, inherited]
 

Set the "kill" flow value.

This value is used in dataflow analyses to store information that is killed at this node. Note that each node has exactly one "kill" flow value.

To set the flow value to be empty, call this method with a value of NULL.

Parameters:
k the new kill flow value.

Definition at line 320 of file ast.h.

References Node::_kill.

FlowVal* Node::kill  )  const [inline, inherited]
 

Get the "kill" flow value.

This value is used in dataflow analyses to store information that is killed at this node. Note that each node has exactly one "kill" flow value.

Returns:
the "kill" flow value.

Definition at line 307 of file ast.h.

References Node::_kill.

typeNode* exprNode::no_tdef_type  )  [inline]
 

Definition at line 3226 of file ast.h.

References type().

virtual void exprNode::output output_context ct,
Node par
[virtual]
 

Generate C code.

Each subclass overrides this method to define how to produce the output C code. To use this method, pass an output_context and a null parent.

Parameters:
ct the output context which describes the formatting.
par the parent node (or null, if at the top of a subtree).

Implements Node.

virtual void exprNode::output_expr output_context ct,
Node par,
int  prec,
Assoc  assoc
[pure virtual]
 

Output a expression.

Implemented in constNode, idNode, binaryNode, unaryNode, castNode, commaNode, ternaryNode, callNode, initializerNode, operandNode, and metaexprNode.

bool exprNode::parens int  outer_prec,
Assoc  outer_assoc
 

Determine if parenthesis are needed.

This method takes the associativity and precedence values of the enclosing expression and determines if parentheses are needed.

See also:
exprNode::output_expr()

exprNode::precedence()

Parameters:
outer_prec the precedence value of the enclosing expression
outer_assoc the associativity value of the enclosing expression
Returns:
true if parentheses are needed.

void Node::parenthesized bool  paren  )  [inline, inherited]
 

Set the parenthesized boolean.

This boolean determines whether this expression will be parenthesized in the output. Note that that the parentheses will always be added when they are needed to disambiguate the output. This variable only controls the use of "un-necessary" parentheses.

Parameters:
paren the new value of the parenthesized boolean.

Definition at line 262 of file ast.h.

References Node::_parenthesized.

bool Node::parenthesized  )  const [inline, inherited]
 

Get the parenthesized boolean.

Returns:
true if the construct corresponding to this Node was parenthesized in the source.

Definition at line 250 of file ast.h.

References Node::_parenthesized.

virtual int exprNode::precedence Assoc assoc  )  [virtual]
 

Associativity and precedence.

Determine the associativity and precedence of the expression. Each exprNode subclass overrides this method to provide the specific results. The default is highest precedence and left-associative.

See also:
exprNode::output_expr()

exprNode::parens()

Parameters:
assoc a reference parameter that is set to the associativity value
Returns:
the precedence value

Reimplemented in binaryNode, unaryNode, castNode, commaNode, and ternaryNode.

static void Node::report  )  [static, inherited]
 

Report node count statistics.

The code can be configured to gather statistics about node usage according to type. This method prints the current state of that accounting information to standard out.

NodeType Node::typ  )  const [inline, inherited]
 

Get the node type.

This has nothing to do with types in the source code. It indicates what kind of AST node this is (e.g., a unary expression node or a while node).

Returns:
the node type.

Definition at line 216 of file ast.h.

References Node::_typ.

Referenced by gcWalker::delete_nodes(), and NodeInfo::nodeIndex().

virtual void exprNode::type typeNode type  )  [inline, virtual]
 

Reimplemented in operandNode.

Definition at line 3179 of file ast.h.

References _type.

virtual typeNode* exprNode::type  )  const [inline, virtual]
 

Return the node data type.

This method returns the C data type of a node. Several different kinds of nodes contain typeNode pointers. This method is just a unified way to access them. It does not attempt to compute the type, it just returns whatever typeNode pointer resides on the node. The subclasses that have types return them, and the others return null.

Returns:
the typeNode pointer on the node.

Reimplemented from Node.

Reimplemented in operandNode.

Definition at line 3177 of file ast.h.

References _type.

Referenced by tree_visitor::at_const(), no_tdef_type(), and constNode::usual_unary_conversion_type().

static pair<exprNode *, exprNode *> exprNode::usual_arithmetic_conversions exprNode left,
exprNode right
[static]
 

Usual arithmetic conversions.

This method takes two expressions and adds any casts that are necessary to make them compatible for arithmetic operations. It calls typeNode::usual_arithmetic_conversions(), passing the types of the expressions, to determine when the casts are needed. It inserts implicit castNode objects above the expressions for the casts.

See also:
castNode
Parameters:
left the left-hand expression
right the right-hand expression
Returns:
the left and right expressions, possibly with casts added

void exprNode::value const constant newval  )  [inline]
 

Definition at line 3183 of file ast.h.

References _value.

constant& exprNode::value  )  [inline]
 

Definition at line 3182 of file ast.h.

References _value.

const constant& exprNode::value  )  const [inline]
 

Definition at line 3181 of file ast.h.

References _value.

virtual void Node::visit Visitor the_visitor  )  [pure virtual, inherited]
 

Dispatch a Visitor.

This abstract method is the entry point for the visitor design pattern. Each node subclass defines a visit() method that calls the appropriate at_ method in the visitor. For more information see the Visitor documentation.

Parameters:
the_visitor the specific Visitor object to use.

Implemented in unitNode, declNode, subdeclNode, procNode, primNode, tdefNode, ptrNode, arrayNode, funcNode, structNode, unionNode, enumNode, suespecNode, constNode, idNode, binaryNode, unaryNode, castNode, commaNode, ternaryNode, callNode, initializerNode, blockNode, basicblockNode, exprstmtNode, labelNode, caseNode, ifNode, switchNode, whileNode, doNode, forNode, gotoNode, continueNode, breakNode, returnNode, attribNode, operandNode, conditiongotoNode, threeAddrNode, textNode, metaexprNode, and metastmtNode.

virtual void Node::walk Walker the_walker  )  [pure virtual, inherited]
 

Dispatch a Walker.

This abstract method works much like the visitor, but instead walks the entire underlying subtree calling the appropriate at_ method at each node. For more information see the Walker documentation.

Parameters:
the_walker the specific Walker object to use.

Implemented in unitNode, declNode, subdeclNode, procNode, primNode, tdefNode, ptrNode, arrayNode, funcNode, structNode, unionNode, enumNode, suespecNode, constNode, idNode, binaryNode, unaryNode, castNode, commaNode, ternaryNode, callNode, initializerNode, blockNode, basicblockNode, exprstmtNode, labelNode, caseNode, ifNode, switchNode, whileNode, doNode, forNode, gotoNode, continueNode, breakNode, returnNode, attribNode, operandNode, conditiongotoNode, threeAddrNode, textNode, metaexprNode, and metastmtNode.

Referenced by gcWalker::at_binary(), sue_complete_walker::check(), and df_number_walker::number().


Member Data Documentation

TREE typeNode* exprNode::_type [private]
 

the type of the expression

This field is only populated by calling the semcheck_walker.

Definition at line 3141 of file ast.h.

Referenced by get_type(), and type().

constant exprNode::_value [private]
 

the value of the expression

This field is only populated by calling the eval() method. For non-constant expressions, the result may be a special "no val" value.

See also:
constant::no_val()

Definition at line 3150 of file ast.h.

Referenced by value().

map<Node *, bool> Node::deleted_nodes [static, inherited]
 

Definition at line 165 of file ast.h.

Referenced by gcWalker::delete_nodes().

bool Node::mark [inherited]
 

Definition at line 168 of file ast.h.

Referenced by gcWalker::at_binary(), and gcWalker::delete_nodes().

node_list Node::nodes [static, inherited]
 

Definition at line 162 of file ast.h.

Referenced by gcWalker::delete_nodes(), and gcWalker::gcWalker().


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

Generated on February 1, 2006
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