Class: Idl::FieldAssignmentAst

Inherits:
AstNode
  • Object
show all
Includes:
Executable
Defined in:
lib/idl/ast.rb

Overview

represents a bitfield or struct assignement

for example:

Sv39PageTableEntry entry;
entry.PPN = 0

Instance Method Summary collapse

Constructor Details

#initialize(input, interval, field_access, write_value) ⇒ FieldAssignmentAst

Returns a new instance of FieldAssignmentAst.



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# File 'lib/idl/ast.rb', line 1962

def initialize(input, interval, field_access, write_value)
  super(input, interval, [field_access, write_value])
end

Instance Method Details

#execute(symtab) ⇒ void

This method returns an undefined value.

“execute” the statement by updating the variables in the symbol table

Parameters:

  • symtab (SymbolTable) —

    The symbol table for the context

Raises:

  • ValueError if some part of the statement cannot be executed at compile time



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# File 'lib/idl/ast.rb', line 1984

def execute(symtab)
  if field_access.type(symtab).kind == :struct
    struct_val = field_access.obj.value(symtab)
    struct_val[field_access.field_name] = write_value.value(symtab)
    symtab.add(field_access.obj.name, Var.new(field_access.obj.name, field_access.obj.type(symtab), struct_val))
  else
    value_error "TODO: Field assignement execution"
  end
end

#execute_unknown(symtab) ⇒ void

This method returns an undefined value.

“execute” the statement, forcing any variable assignments to an unknown state This is used down unknown conditional paths.

Parameters:

  • symtab (SymbolTable) —

    The symbol table for the context

Raises:

  • ValueError if some part of the statement cannot be executed at compile time



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# File 'lib/idl/ast.rb', line 1995

def execute_unknown(symtab)
  symtab.add(field_access.obj.name, Var.new(field_access.obj.name, field_access.obj.type(symtab), nil))
end

#field_access ⇒ Object 



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# File 'lib/idl/ast.rb', line 1959

def field_access = @children[0]

#to_idl ⇒ String

Return valid IDL representation of the node (and its subtree)

Returns:

  • (String) —

    IDL code for the node



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# File 'lib/idl/ast.rb', line 2000

def to_idl = "#{field_access.to_idl} = #{write_value.to_idl}"

#type(symtab) ⇒ Type

Given a specific symbol table, return the type of this node.

Should not be called until #type_check is called with the same arguments

Parameters:

Returns:

  • (Type) —

    The type of the node

Raises:



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# File 'lib/idl/ast.rb', line 1967

def type(symtab)
  field_access.type(symtab)
end

#type_check(symtab) ⇒ void

This method returns an undefined value.

type check this node and all children

Calls to #type and/or #value may depend on type_check being called first with the same symtab. If not, those functions may raise an AstNode::InternalError

Parameters:

Raises:



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# File 'lib/idl/ast.rb', line 1972

def type_check(symtab)
  field_access.type_check(symtab)

  type_error "Cannot write const variable" if field_access.type(symtab).const?

  write_value.type_check(symtab)
  return if write_value.type(symtab).convertable_to?(type(symtab))

  type_error "Incompatible type in assignment (#{type(symtab)}, #{write_value.type(symtab)})"
end

#write_value ⇒ Object 



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# File 'lib/idl/ast.rb', line 1960

def write_value = @children[1]