Class: Tem::Builders::Assembler

Inherits:
Object
  • Object
show all
Defined in:
lib/tem/builders/assembler.rb

Overview

Builder class for the code assembler builder.

Defined Under Namespace

Modules: CodeBuilderBase Classes: ProxyBase

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(target) ⇒ Assembler

Creates a builder targeting a module / class.



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# File 'lib/tem/builders/assembler.rb', line 244

def initialize(target)
  @target = target
  @isa, @abi, @proxy = nil, nil, nil    
end

Instance Attribute Details

#target ⇒ Object (readonly)

The module / class impacted by the builder.



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# File 'lib/tem/builders/assembler.rb', line 241

def target
  @target
end

Class Method Details

.define_assembler(class_or_module) {|new(class_or_module)| ... } ⇒ Object

Creates a builder targeting a module / class.

The given parameter should be a class or module.

Yields:

  • (new(class_or_module)) 


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# File 'lib/tem/builders/assembler.rb', line 16

def self.define_assembler(class_or_module)  # :yields: abi
  yield new(class_or_module)
end

Instance Method Details

#augment_target ⇒ Object

(private) Augments the target with the assemble method.



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# File 'lib/tem/builders/assembler.rb', line 210

def augment_target
  # Capture this data in the closure.
  proxy_class = @proxy_class
  builder_class = @builder_class
  defines = Proc.new do
    # Assembles code.
    def assemble(&block)
      _assemble block
    end
    
    # Internal method for assembling code.
    #
    # We need to use a block to define this method, so we can capture the
    # outer variables (proxy_class and builder_class) in its closure. However,
    # blocks can't take blocks as parameters (at least not in MRI 1.8). So
    # we use a regular method definition (assemble) which wraps the block
    # into a Proc received by _assemble.
    define_method :_assemble do |block|
      code_builder = builder_class.new
      code_builder.start_assembling
      proxy = proxy_class.new(code_builder)
      block.call proxy
      code_builder.done_assembling proxy
    end
    private :_assemble
  end
  @target.class_eval(&defines)
  (class << @target; self; end).module_eval(&defines)        
end

#data_directive(name, options = {}) ⇒ Object

Defines the methods for implementing a data-emitting directive.

The following method is defined in the proxy for a directive named ‘name’:

* name(abi_type, values = 1) -> emits the given values as abi_type



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# File 'lib/tem/builders/assembler.rb', line 133

def data_directive(name, options = {})
  unless @proxy_class
    raise "target_isa must be called before other builder methods"
  end
  # Capture this in the closure.
  abi = @abi
  proxy_defines = Proc.new do
    define_method name.to_sym do |abi_type, values|
      values = [values] unless values.instance_of? Array
      data = []
      values.each { |value| data += abi.send :"to_#{abi_type}", value }
      @assembler.emit_bytes :immed, :emit => data
    end
  end    
  @proxy_class.class_eval(&proxy_defines)
  (class << @proxy_class; self; end).module_eval(&proxy_defines)    
end

#label_directive(name, options = {}) ⇒ Object

Defines the methods for implementing a labeling directive.

The following method is defined in the proxy for a directive named ‘name’:

* name(label_name) -> creates a label named label_name at the current byte



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# File 'lib/tem/builders/assembler.rb', line 74

def label_directive(name, options = {})
  unless @proxy_class
    raise "target_isa must be called before other builder methods"
  end
  proxy_defines = Proc.new do
    define_method name.to_sym do |label_name|
      @assembler.emit_label label_name.to_sym
    end
  end    
  @proxy_class.class_eval(&proxy_defines)
  (class << @proxy_class; self; end).module_eval(&proxy_defines)    
end

#special_label_directive(name, label_name) ⇒ Object

Defines the methods for implementing a special label directive.

The following method is defined in the proxy for a directive named ‘name’:

* name -> creates a label named label_name at the current byte



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# File 'lib/tem/builders/assembler.rb', line 91

def special_label_directive(name, label_name)
  unless @proxy_class
    raise "target_isa must be called before other builder methods"
  end
  proxy_defines = Proc.new do
    define_method name.to_sym do
      @assembler.emit_label label_name.to_sym
    end
  end    
  @proxy_class.class_eval(&proxy_defines)
  (class << @proxy_class; self; end).module_eval(&proxy_defines)
end

#stack_directive(name, options) ⇒ Object

Defines the methods for implementing a stack directive.

The following options are supported:

label:: the label serving as the stack marker (required)
slot_type:: the ABI type representing a stack slot

The following method is defined in the proxy for a directive named ‘name’:

* name(slots = 0) -> places a stack marker and allocates stack slots



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# File 'lib/tem/builders/assembler.rb', line 43

def stack_directive(name, options)
  unless @proxy_class
    raise "target_isa must be called before other builder methods"
  end
  # Capture these in the closure.
  stack_label = options[:label]
  slot_length = @abi.send :"#{options[:slot_type]}_length" 
  proxy_defines = Proc.new do
    define_method name.to_sym do |*args|
      case args.length
      when 0
        slots = 0
      when 1
        slots = args.first
      else
        raise "#{name}: given #{args.length} arguments, wanted at most 1"
      end
      @assembler.emit_label stack_label
      if slots > 0
        @assembler.emit_bytes name, :emit => Array.new(slots * slot_length, 0)
      end
    end
  end    
  @proxy_class.class_eval(&proxy_defines)
  (class << @proxy_class; self; end).module_eval(&proxy_defines)    
end

#target_isa(isa_module) ⇒ Object

Defines the ISA targeted by the assembler.

This method should be called early in the assembler definition. It creates the proxy and builder classes for the assembling process.



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# File 'lib/tem/builders/assembler.rb', line 24

def target_isa(isa_module)    
  @isa = isa_module
  target.const_set :Isa, @isa
  @abi = @isa.const_get :Abi
  target.const_set :Abi, @abi
  
  define_proxy_class
  define_builder_class
  augment_target
end

#zeros_directive(name, options = {}) ⇒ Object

Defines the methods for implementing a zero-inserting directive.

The following method is defined in the proxy for a directive named ‘name’:

* name(abi_type, count = 1) -> creates count zeros of abi_type



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# File 'lib/tem/builders/assembler.rb', line 108

def zeros_directive(name, options = {})
  unless @proxy_class
    raise "target_isa must be called before other builder methods"
  end
  # Capture this in the closure.
  abi = @abi
  proxy_defines = Proc.new do
    define_method name.to_sym do |*args|
      if args.length == 1 || args.length == 2
        type_name, count = args[0], args[1] || 1
      else
        raise "#{name}: given #{args.length} arguments, wanted 1 or 2"
      end
      bytes = count * abi.send(:"#{type_name}_length")
      @assembler.emit_bytes name, :emit => Array.new(bytes, 0)
    end
  end    
  @proxy_class.class_eval(&proxy_defines)
  (class << @proxy_class; self; end).module_eval(&proxy_defines)    
end