Class: SyntaxTree::YARV::Instruction

Inherits:

Object

• Object
• SyntaxTree::YARV::Instruction

Defined in:

lib/syntax_tree/yarv/instructions.rb

Overview

This is a base class for all YARV instructions. It provides a few convenience methods for working with instructions.

Direct Known Subclasses

AdjustStack, AnyToString, BranchIf, BranchNil, BranchUnless, CheckKeyword, CheckMatch, CheckType, ConcatArray, ConcatStrings, DefineClass, DefineMethod, DefineSMethod, Defined, DefinedIVar, Dup, DupArray, DupHash, DupN, ExpandArray, GetBlockParam, GetBlockParamProxy, GetClassVariable, GetConstant, GetGlobal, GetInstanceVariable, GetLocal, GetLocalWC0, GetLocalWC1, GetSpecial, Intern, InvokeBlock, InvokeSuper, Jump, Leave, Legacy::GetClassVariable, Legacy::OptGetInlineCache, Legacy::OptSetInlineCache, Legacy::SetClassVariable, NewArray, NewArrayKwSplat, NewHash, NewRange, Nop, ObjToString, Once, OptAnd, OptAref, OptArefWith, OptAset, OptAsetWith, OptCaseDispatch, OptDiv, OptEmptyP, OptEq, OptGE, OptGT, OptGetConstantPath, OptLE, OptLT, OptLTLT, OptLength, OptMinus, OptMod, OptMult, OptNEq, OptNewArrayMax, OptNewArrayMin, OptNilP, OptNot, OptOr, OptPlus, OptRegExpMatch2, OptSendWithoutBlock, OptSize, OptStrFreeze, OptStrUMinus, OptSucc, Pop, PutNil, PutObject, PutObjectInt2Fix0, PutObjectInt2Fix1, PutSelf, PutSpecialObject, PutString, Send, SetBlockParam, SetClassVariable, SetConstant, SetGlobal, SetInstanceVariable, SetLocal, SetLocalWC0, SetLocalWC1, SetN, SetSpecial, SplatArray, Swap, Throw, ToRegExp, TopN

Instance Method Summary

• #branch_targets ⇒ Object

  This returns an array of labels.

• #canonical ⇒ Object

  This method creates an instruction that represents the canonical (non-specialized) form of this instruction.

• #falls_through? ⇒ Boolean

  Whether or not this instruction falls through to the next instruction if its branching fails.

• #leaves? ⇒ Boolean

  Whether or not this instruction leaves the current frame.

• #length ⇒ Object

  This returns the size of the instruction in terms of the number of slots it occupies in the instruction sequence.

• #pops ⇒ Object

  This returns the number of values that are popped off the stack.

• #pushes ⇒ Object

  This returns the number of values that are pushed onto the stack.

• #side_effects? ⇒ Boolean

  Does the instruction have side effects? Control-flow counts as a side-effect, as do some special-case instructions like Leave.

Instance Method Details

#branch_targets ⇒ Object

This returns an array of labels.

# File 'lib/syntax_tree/yarv/instructions.rb', line 33

def branch_targets
  []
end

#canonical ⇒ Object

This method creates an instruction that represents the canonical (non-specialized) form of this instruction. If this instruction is not a specialized instruction, then this method returns ‘self`.

# File 'lib/syntax_tree/yarv/instructions.rb', line 11

def canonical
  self
end

#falls_through? ⇒ Boolean

Whether or not this instruction falls through to the next instruction if its branching fails.

Returns:

• (Boolean)

# File 'lib/syntax_tree/yarv/instructions.rb', line 44

def falls_through?
  false
end

#leaves? ⇒ Boolean

Whether or not this instruction leaves the current frame.

Returns:

• (Boolean)

# File 'lib/syntax_tree/yarv/instructions.rb', line 38

def leaves?
  false
end

#length ⇒ Object

This returns the size of the instruction in terms of the number of slots it occupies in the instruction sequence. Effectively this is 1 plus the number of operands.

# File 'lib/syntax_tree/yarv/instructions.rb', line 18

def length
  1
end

#pops ⇒ Object

This returns the number of values that are popped off the stack.

# File 'lib/syntax_tree/yarv/instructions.rb', line 28

def pops
  0
end

#pushes ⇒ Object

This returns the number of values that are pushed onto the stack.

# File 'lib/syntax_tree/yarv/instructions.rb', line 23

def pushes
  0
end

#side_effects? ⇒ Boolean

Does the instruction have side effects? Control-flow counts as a side-effect, as do some special-case instructions like Leave. By default every instruction is marked as having side effects.

Returns:

• (Boolean)

# File 'lib/syntax_tree/yarv/instructions.rb', line 51

def side_effects?
  true
end