Class: MiniRuby::VM

Inherits:
Object
  • Object
show all
Extended by:
T::Sig
Defined in:
lib/miniruby/vm.rb

Overview

MiniRuby stack based Virtual Machine. Executes a chunk of bytecode produced by the compiler.

Constant Summary collapse

Func = 
T.type_alias { T.proc.params(vm: VM, args: T::Array[Object]).returns(Object) }

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(bytecode, stdout: $stdout, stdin: $stdin) ⇒ VM

: (BytecodeFunction bytecode, ?stdout: IO, ?stdin: IO) -> void



40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
 
# File 'lib/miniruby/vm.rb', line 40

def initialize(bytecode, stdout: $stdout, stdin: $stdin)
  # the currently executed chunk of bytecode
  @bytecode = bytecode
  # standard output used by the VM
  @stdout = stdout
  # standard input used by the VM
  @stdin = stdin

  # The value stack
  @stack = [Object.new] #: Array[Object]
  # Instruction pointer -- points to the next bytecode instruction
  @ip = 0 #: Integer
  # Stack pointer -- points to the offset on the stack where the next value will be pushed to
  @sp = 1 #: Integer
end

Class Attribute Details

.functions ⇒ Object (readonly)

: Hash[Symbol, NativeFunction]



68
69
70
 
# File 'lib/miniruby/vm.rb', line 68

def functions
  @functions
end

Instance Attribute Details

#bytecode ⇒ Object (readonly)

: BytecodeFunction



31
32
33
 
# File 'lib/miniruby/vm.rb', line 31

def bytecode
  @bytecode
end

#stdin ⇒ Object (readonly)

: IO



37
38
39
 
# File 'lib/miniruby/vm.rb', line 37

def stdin
  @stdin
end

#stdout ⇒ Object (readonly)

: IO



34
35
36
 
# File 'lib/miniruby/vm.rb', line 34

def stdout
  @stdout
end

Class Method Details

.define(name, param_count = 0, &func) ⇒ Object

: (Symbol name, ?Integer param_count) { (?) -> untyped } -> void



63
64
65
 
# File 'lib/miniruby/vm.rb', line 63

def define(name, param_count = 0, &func)
  @functions[name] = NativeFunction.new(name:, param_count:, &func)
end

.interpret(source, name: '<main>', filename: '<main>', stdout: $stdout, stdin: $stdin) ⇒ Object

: (String source, ?name: String, ?filename: String, ?stdout: IO, ?stdin: IO) -> Object



24
25
26
27
 
# File 'lib/miniruby/vm.rb', line 24

def interpret(source, name: '<main>', filename: '<main>', stdout: $stdout, stdin: $stdin)
  bytecode = Compiler.compile_source(source, name:, filename:)
  run(bytecode, stdout:, stdin:)
end

.run(bytecode, stdout: $stdout, stdin: $stdin) ⇒ Object

: (BytecodeFunction bytecode, ?stdout: IO, ?stdin: IO) -> Object



17
18
19
20
21
 
# File 'lib/miniruby/vm.rb', line 17

def run(bytecode, stdout: $stdout, stdin: $stdin)
  vm = new(bytecode, stdout:, stdin:)
  vm.run
  vm.stack_top
end

Instance Method Details

#inspect_stack ⇒ Object

: -> void



185
186
187
 
# File 'lib/miniruby/vm.rb', line 185

def inspect_stack
  @stdout.print("#{@stack[...@sp].inspect}\n")
end

#run ⇒ Object

: -> void



85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
 
# File 'lib/miniruby/vm.rb', line 85

def run
  while true
    opcode = read_byte
    case opcode
    when Opcode::TRUE
      push(true)
    when Opcode::FALSE
      push(false)
    when Opcode::NIL
      push(nil)
    when Opcode::POP
      pop()
    when Opcode::DUP
      push(peek)
    when Opcode::INSPECT_STACK
      inspect_stack()
    when Opcode::ADD
      right = pop()
      left = pop() #: as untyped
      push(left + right)
    when Opcode::SUBTRACT
      right = pop
      left = pop #: as untyped
      push(left - right)
    when Opcode::MULTIPLY
      right = pop
      left = pop #: as untyped
      push(left * right)
    when Opcode::DIVIDE
      right = pop
      left = pop #: as untyped
      push(left / right)
    when Opcode::EQUAL
      right = pop
      left = pop #: as untyped
      push(left == right)
    when Opcode::GREATER
      right = pop
      left = pop #: as untyped
      push(left > right)
    when Opcode::GREATER_EQUAL
      right = pop
      left = pop #: as untyped
      push(left >= right)
    when Opcode::LESS
      right = pop
      left = pop #: as untyped
      push(left < right)
    when Opcode::LESS_EQUAL
      right = pop
      left = pop #: as untyped
      push(left <= right)
    when Opcode::NOT
      value = pop
      push(!value)
    when Opcode::NEGATE
      value = pop #: as untyped
      push(-value)
    when Opcode::LOAD_VALUE
      index = read_byte
      push(get_value(index))
    when Opcode::SELF
      push_local(0)
    when Opcode::PREP_LOCALS
      @sp += read_byte
    when Opcode::GET_LOCAL
      push_local(read_byte)
    when Opcode::SET_LOCAL
      value = peek
      local_index = read_byte
      set_local(local_index, value)
    when Opcode::JUMP
      offset = read_byte
      @ip += offset
    when Opcode::LOOP
      offset = read_byte
      @ip -= offset
    when Opcode::JUMP_UNLESS
      condition = pop
      offset = read_byte
      next if condition

      @ip += offset
    when Opcode::CALL
      index = read_byte
      call_info = get_value(index) #: as CallInfo
      to_pop = call_info.arg_count + 1
      args = @stack[(@sp - to_pop)...@sp] #: as !nil
      result = self.class.functions.fetch(call_info.name).call(self, args)
      args.each { pop }
      push(result)
    when Opcode::RETURN
      return
    else
      raise ArgumentError, "invalid opcode: #{opcode}"
    end
  end
end

#stack_top ⇒ Object

: -> Object



190
191
192
 
# File 'lib/miniruby/vm.rb', line 190

def stack_top
  @stack[@sp - 1]
end