Class: SyntaxTree::YARV::GetInstanceVariable

Inherits:
Instruction
  • Object
show all
Defined in:
lib/syntax_tree/yarv/instructions.rb

Overview

### Summary

‘getinstancevariable` pushes the value of an instance variable onto the stack. It uses an inline cache to avoid having to look up the instance variable in the class hierarchy every time.

This instruction has two forms, but both have the same structure. Before Ruby 3.2, the inline cache corresponded to both the get and set instructions and could be shared. Since Ruby 3.2, it uses object shapes instead so the caches are unique per instruction.

### Usage

~~~ruby ~~~

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Instruction

#branch_targets, #canonical, #falls_through?, #leaves?, #pops, #side_effects?

Constructor Details

#initialize(name, cache) ⇒ GetInstanceVariable

Returns a new instance of GetInstanceVariable.



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1828

def initialize(name, cache)
  @name = name
  @cache = cache
end

Instance Attribute Details

#cache ⇒ Object (readonly)

Returns the value of attribute cache.



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1826

def cache
  @cache
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1826

def name
  @name
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1848

def ==(other)
  other.is_a?(GetInstanceVariable) && other.name == name &&
    other.cache == cache
end

#call(vm) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1861

def call(vm)
  method = Object.instance_method(:instance_variable_get)
  vm.push(method.bind(vm.frame._self).call(name))
end

#deconstruct_keys(_keys) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1844

def deconstruct_keys(_keys)
  { name: name, cache: cache }
end

#disasm(fmt) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1833

def disasm(fmt)
  fmt.instruction(
    "getinstancevariable",
    [fmt.object(name), fmt.inline_storage(cache)]
  )
end

#length ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1853

def length
  3
end

#pushes ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1857

def pushes
  1
end

#to_a(_iseq) ⇒ Object 



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# File 'lib/syntax_tree/yarv/instructions.rb', line 1840

def to_a(_iseq)
  [:getinstancevariable, name, cache]
end