103
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1 """
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2 Generates ir code from ast tree.
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3 """
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4
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5 from .nodes import *
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6 from ...core.errors import Error
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7 from ... import core
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8 from .builtin import real, integer, boolean, char
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9 #from .assembler import *
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10
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11 class KsIrGenerator:
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12 def __init__(self):
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13 pass
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14
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15 # Code generation functions:
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16 def genexprcode(self, node):
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17 """
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18 Generate code for expressions!
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19 Recursively evaluates, and ensures a register contains the answer.
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20 register is an integer register or a floating point reg
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21 """
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22 if isinstance(node, Binop):
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23 """ Handle a binary operation (two arguments) of some kind """
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24 self.genexprcode(node.a)
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25 self.genexprcode(node.b)
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26
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27 if node.op == 'mod':
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28 assert(node.typ.isType(integer))
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29 self.addCode(mov('rax', node.a.reg))
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30 elif node.op == 'div':
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31 assert(node.typ.isType(integer))
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32 self.addCode(mov('rax', node.a.reg))
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33 elif node.op == '*':
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34 if node.typ.isType(integer):
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35 self.addCode(imulreg64(node.a.reg, node.b.reg))
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36 elif node.op == '+':
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37 if node.typ.isType(integer):
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38 self.addCode(addreg64(node.a.reg, node.b.reg))
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39 elif node.op == '-':
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40 if node.typ.isType(integer):
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41 self.addCode(subreg64(node.a.reg, node.b.reg))
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42 else:
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43 Error('Unknown Binop {0}'.format(node.op))
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44
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45 elif type(node) is Unop:
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46 if node.op == 'INTTOREAL':
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47 self.genexprcode(node.a)
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48 node.reg = node.a.reg
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49 # TODO use 'FILD' instruction
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50 freg = 12
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51 code.append('Unop inttoreal TODO')
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52 elif node.op == 'ABS':
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53 if isType(node.typ, real):
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54 code = [0xD9, 0xE1] # st(0) = fabs st(0)
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55 Error('ABS error integer')
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56 elif isType(node.typ, integer):
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57 code = []
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58 Error('ABS error integer')
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59 else:
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60 Error('ABS error')
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61 else:
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62 Error('Unknown Unop {0}'.format(node.op))
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63
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64 elif isinstance(node, Designator):
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65 # dereference, array index. Make sure that the result comes into a register
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66 if len(node.selectors) > 0:
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67 self.gencode(node) # Load the pointer into some register
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68
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69 # Now we can access the object at location '[node.reg]':
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70 if node.typ.isType(integer):
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71 self.addCode( mov(node.reg, [node.reg, 0x0]) )
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72 else:
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73 Error('Only integer types implemented')
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74 else:
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75 # No selectors, load variable directly
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76 if node.obj.typ.isType(integer):
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77 if type(node.obj) is Constant:
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78 self.genexprcode(node.obj)
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79 node.reg = node.obj.reg
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80 else:
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81 self.getreg(node)
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82 # Get a register to store the integer value
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83 if node.obj.isLocal:
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84 # relative to rbp:
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85 self.addCode( mov(node.reg, ['rbp', node.obj.offset]) )
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86 else:
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87 self.addCode(mov(node.reg, ['RIP', 0x0]))
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88 self.fixCode(self.rip-4, imm32(node.obj.offset - self.rip))
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89 else:
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90 Error('Cannot load variable type {0}'.format(node.typ))
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91
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92 elif isinstance(node, Relop):
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93 # Create a boolean from operands
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94 # TODO create an alternative for expressions used as conditions.
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95 self.genexprcode(node.a)
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96 self.genexprcode(node.b)
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97
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98 if node.a.typ.isType(integer):
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99 self.freereg(node.b)
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100 else:
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101 Error('Relop not implemented for {0}'.format(node.a.typ))
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102
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103 elif type(node) is Constant:
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104 if node.typ.isType(integer):
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105 self.getreg(node)
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106
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107 elif type(node) is ProcedureCall:
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108 if type(node.proc.obj) is BuiltinProcedure:
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109 # Handle builtin procedures different, these not always call
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110 # a function, but generate code.
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111 bi = node.proc.obj
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112 if bi.name == 'chr':
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113 arg = node.args[0]
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114 self.genexprcode(arg)
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115 # Store character in full width register:
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116 # TODO: store in char only register
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117 node.reg = arg.reg
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118 else:
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119 Error('Unknown builtin function {0}'.format(bi.name))
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120 else:
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121 # Use generic procedure call first
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122 self.gencode(node)
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123 # Retrieve result:
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124 if node.typ.isType(integer):
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125 # Store result!
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126 self.getreg(node)
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127 self.addCode( mov(node.reg, 'rax') )
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128 else:
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129 Error('Return type not supported {0}'.format(node.typ))
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130 else:
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131 Error('Cannot generate expression code for: {0}'.format(node))
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132
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133 def gencode(self, node):
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134 """ Code generation function for AST nodes """
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135 if isinstance(node, Module):
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136 # TODO: recurse!
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137 return core.Module()
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138
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139 elif type(node) is Procedure:
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140 # calculate offsets for local variables and parameters
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141 # Variable location relative to 'rbp' register
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142 variables = node.symtable.getAllLocal(Variable)
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143 offset = 0
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144 paramoffset = 16
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145 for var in variables:
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146 var.isLocal = True
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147 if not var.isParameter:
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148 offset += var.typ.size
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149 # Offset is negative of rbp in stack frame
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150 var.offset = -offset
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151 node.framesize = offset
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152 # Calculate offsets of parameters relative to rbp register
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153 for par in reversed(node.typ.parameters):
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154 pvar = node.symtable.getLocal(Variable, par.name)
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155 pvar.offset = paramoffset
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156 paramoffset += pvar.typ.size
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157
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158 # code generation
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159 node.entrypoint = self.rip
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160 self.addCode(push('rbp'))
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161 self.addCode(mov('rbp', 'rsp')) # Setup the base pointer
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162 self.addCode(subreg64('rsp', node.framesize)) # reserve space for locals
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163 self.gencode(node.block)
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164 if node.retexpr:
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165 if node.retexpr.typ.isType(integer):
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166 self.genexprcode(node.retexpr)
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167 self.addCode( mov('rax', node.retexpr.reg) )
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168 self.freereg(node.retexpr)
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169 else:
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170 Error('Cannot return this kind yet {0}'.format(node.retexpr.typ))
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171 self.addCode( addreg64('rsp', node.framesize) )
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172 self.addCode( pop('rbp') )
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173 self.addCode( ret() )
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174 assert(len(self.usedregs) == 0)
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175
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176 elif isinstance(node, StatementSequence):
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177 for s in node.statements:
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178 self.gencode(s)
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179
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180 elif type(node) is ProcedureCall:
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181 # Prepare parameters on the stack:
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182 stacksize = 0
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183 assert(len(node.args) == len(node.proc.typ.parameters))
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184 for arg, param in zip(node.args, node.proc.typ.parameters):
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185
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186 if param.kind == 'value':
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187 self.genexprcode(arg)
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188 self.addCode( push(arg.reg) )
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189 self.freereg( arg )
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190 stacksize += 8
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191 else:
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192 Error('Parameter kind other than value')
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193
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194 # Calculate address using designator
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195 if type(node.proc.obj) is Procedure:
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196 self.addCode( call(0x0) )
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197 self.fixCode( self.rip - 4, imm32(node.proc.obj.entrypoint - self.rip))
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198 elif type(node.proc.obj) is ImportedSymbol:
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199 # Load the entry point of the import table
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200 self.getreg(node.proc.obj)
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201 # Load the address of the procedure:
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202 self.addCode( mov(node.proc.obj.reg, ['RIP', 0x0]) )
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203 self.fixCode( self.rip - 4, imm32(node.proc.obj.offset - self.rip) )
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204 # Call to the address in register:
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205 self.addCode( call(node.proc.obj.reg) )
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206 # Free register that holds the address of the object
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207 self.freereg( node.proc.obj )
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208 elif type(node.proc.obj) is BuiltinProcedure:
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209 if node.proc.obj.name == 'chr':
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210 print('int to char')
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211 else:
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212 Error('Unknown builtin function {0}'.format(node.proc.obj.name))
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213 else:
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214 Error('Cannot call designator of type {0}'.format(node.proc.obj))
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215
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216 # Restore stack (pop all arguments of):
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217 self.addCode(addreg64('rsp', stacksize))
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218
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219 elif type(node) is Assignment:
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220 if node.lval.typ.isType(integer):
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221 # TODO if node.rval is Constant of some datatype, move it to mem directly
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222 self.genexprcode(node.rval) # Calculate the value that has to be stored.
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223 self.storeRegInDesignator(node.rval.reg, node.lval)
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224 self.freereg(node.rval)
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225 else:
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226 Error('Assignments of other types not implemented')
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227 # TODO if left and right are designators, do some sort of memcpy.
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228
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229 elif type(node) is IfStatement:
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230 self.genexprcode(node.condition)
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231 self.addCode( cmpreg64(node.condition.reg, 1) )
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232 self.freereg(node.condition)
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233 if node.falsestatement:
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234 # If with else clause
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235 self.addCode( nearjump(0x0, condition='NE') ) # if Not Equal jump to false
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236 rip1 = self.rip
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237 fixloc1 = self.rip - 4
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238 self.gencode(node.truestatement)
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239 self.addCode( nearjump( 0x0 ) ) # jump over false code
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240 fixloc2 = self.rip - 4
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241 self.fixCode(fixloc1, imm32(self.rip - rip1))
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242 rip2 = self.rip
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243 self.gencode(node.falsestatement)
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244 self.fixCode(fixloc2, imm32(self.rip - rip2))
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245 else:
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246 # If without else clause
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247 self.addCode( nearjump(0x0, condition='NE') ) # if Not Equal jump to false
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248 rip1 = self.rip
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249 fixloc1 = self.rip - 4
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250 self.gencode(node.truestatement)
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251 self.fixCode(fixloc1, imm32(self.rip - rip1)) # Fixup near jump over true code.
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252
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253 elif isinstance(node, WhileStatement):
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254 rip1 = self.rip # Store the start of the while loop
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255 self.genexprcode(node.condition)
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256 self.addCode( cmpreg64(node.condition.reg, 1) ) # Test condition for true-ness
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257 self.freereg(node.condition)
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258 self.addCode( nearjump(0x0, condition='NE') ) # If Not Equal jump over while code AND jump back (fix later)
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259 fixloc1 = self.rip - 4
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260 rip2 = self.rip
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261 self.gencode(node.dostatements)
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262 self.addCode( nearjump(0x0) ) # JMP to condition, fix exact jump position below
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263 fixloc2 = self.rip - 4
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264 rip3 = self.rip # end of while loop
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265 self.fixCode(fixloc2, imm32(rip1 - rip3)) # Fixup jump to start of while loop
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266 self.fixCode(fixloc1, imm32(rip3 - rip2)) # Fixup jump out of while loop
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267
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268 elif type(node) is ForStatement:
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269 # Initial load of iterator variable:
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270 self.genexprcode(node.begin)
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271 self.genexprcode(node.end)
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272 # TODO: link reg with variable so that a register is used instead of a variable
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273 iterreg = node.begin.reg # Get the register used for the loop
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274 #self.addCode(cmpreg64(iterreg, node.endvalue))
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275 rip1 = self.rip
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276 self.gencode(node.statements)
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277 #self.loadDesignatorInReg(node.
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278 #self.addCode( addreg64(node.variable, node.increment) )
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279 self.addCode(nearjump(0x0))
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280 fixloc1 = self.rip - 4
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281 rip2 = self.rip
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282 self.fixCode(fixloc1, imm32(rip1 - rip2))
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283
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284 self.freereg(node.begin) # Release register used in loop
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285 self.freereg(node.end)
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286 Error('No implementation of FOR statement')
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287
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288 elif type(node) is AsmCode:
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289 def processOperand(op):
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290 if type(op) is list:
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291 if type(op[0]) is Variable:
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292 var = op[0]
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293 if var.isLocal:
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294 return ['rbp', var.offset]
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295 else:
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296 Error('Can only use local variables in inline assembler')
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297 return op
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298 for asmline in node.asmcode:
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299 opcode, operands = asmline
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300 operands = [processOperand(opx) for opx in operands]
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301 print('assembling', opcode, *operands)
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302 func,nargs = opcodes[opcode]
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303 code = func(*operands)
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304 self.addCode(code)
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305
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306 elif isinstance(node, EmptyStatement):
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307 pass
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308
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309 elif type(node) is StringConstant:
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310 self.strings.append(node)
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311 self.data.append(node.value) # Add string to the data section
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312
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313 elif type(node) is Designator:
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314 if len(node.selectors) > 0:
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315 self.getreg(node)
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316 # Load starting address
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317 if node.obj.isLocal:
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318 self.addCode( leareg64(node.reg, ['rbp', node.obj.offset]) )
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319 else:
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320 # Global variables need to be relocated...
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321 self.addCode(leareg64(node.reg, ['RIP', 0]))
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322 self.fixCode(self.rip - 4, imm32(node.obj.offset - self.rip))
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323 # Loop over all designators..
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324 for selector in node.selectors:
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325 if type(selector) is Index:
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326 # Deref an array index
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327 self.genexprcode(selector.index)
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328 self.getreg(selector)
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329 self.addCode( mov(selector.reg, selector.typ.elementType.size) )
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330 self.addCode( imulreg64(selector.reg, selector.index.reg ) )
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331 self.freereg(selector.index)
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332 self.addCode(addreg64(node.reg, selector.reg))
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333 self.freereg(selector)
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334 elif type(selector) is Field:
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335 print('Field')
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336 Error('Field not implemented')
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337 else:
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338 Error('Unknown selector')
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339 else:
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340 Error('Can only gencode for designator with selectors')
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341
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342 else:
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343 print('not generating code for {0}'.format(node))
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344
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345 def generateIr(self, ast):
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346 """ ir generation front end """
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347 return self.gencode(ast)
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348
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