346
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1 from ... import ir
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2 from ..basetarget import Label, Alignment
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3 from ...irmach import AbstractInstruction, Frame
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4 from .instructions import Dcd, Add, Sub, Push, Pop, Mov
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5 from .registers import R0, R1, R2, R3, R4, R5, R6, R7, R8, R11, LR, PC, SP
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6
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7
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8 class ArmFrame(Frame):
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9 """ Arm specific frame for functions. """
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10 def __init__(self, name):
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11 # We use r7 as frame pointer.
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12 super().__init__(name)
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13 self.regs = [R0, R1, R2, R3, R4, R5, R6, R7, R8]
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14 self.rv = ir.Temp('special_RV')
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15 self.p1 = ir.Temp('special_P1')
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16 self.p2 = ir.Temp('special_P2')
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17 self.p3 = ir.Temp('special_P3')
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18 self.p4 = ir.Temp('special_P4')
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19 self.fp = ir.Temp('special_FP')
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20 # Pre-colored registers:
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21 self.tempMap = {}
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22 self.tempMap[self.rv] = R0
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23 self.tempMap[self.p1] = R1
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24 self.tempMap[self.p2] = R2
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25 self.tempMap[self.p3] = R3
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26 self.tempMap[self.p4] = R4
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27 self.tempMap[self.fp] = R11
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28 self.locVars = {}
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29 self.parMap = {}
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30 # Literal pool:
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31 self.constants = []
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32
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33 def argLoc(self, pos):
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34 """
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35 Gets the function parameter location in IR-code format.
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36 """
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37 if pos == 0:
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38 return self.p1
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39 elif pos == 1:
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40 return self.p2
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41 elif pos == 2:
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42 return self.p3
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43 elif pos == 3:
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44 return self.p4
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45 else:
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46 raise NotImplementedError('No more than 4 parameters implemented')
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47
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48 def allocVar(self, lvar):
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49 if lvar not in self.locVars:
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50 self.locVars[lvar] = self.stacksize
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51 self.stacksize = self.stacksize + 4
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52 return self.locVars[lvar]
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53
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54 def addConstant(self, value):
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55 lab_name = '{}_literal_{}'.format(self.name, len(self.constants))
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56 self.constants.append((lab_name, value))
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57 return lab_name
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58
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59 def prologue(self):
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60 """ Returns prologue instruction sequence """
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61 pre = [
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62 Label(self.name), # Label indication function
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63 Push({LR, R11})
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64 ]
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65 if self.stacksize > 0:
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66 pre.append(Sub(SP, SP, self.stacksize)) # Reserve stack space
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67 pre += [
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68 Mov(R11, SP) # Setup frame pointer
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69 ]
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70 return pre
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71
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72 def epilogue(self):
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73 """ Return epilogue sequence for a frame. Adjust frame pointer and add constant pool """
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74 post = []
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75 if self.stacksize > 0:
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76 post.append(Add(SP, SP, self.stacksize))
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77 post += [
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78 Pop({PC, R11}),
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79 Alignment(4) # Align at 4 bytes
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80 ]
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81 # Add constant literals:
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82 for ln, v in self.constants:
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83 post.extend([Label(ln), Dcd(v)])
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84 return post
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85
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86 def EntryExitGlue3(self):
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87 """
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88 Add code for the prologue and the epilogue. Add a label, the
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89 return instruction and the stack pointer adjustment for the frame.
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90 """
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91 for index, ins in enumerate(self.prologue()):
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92 self.instructions.insert(index, AbstractInstruction(ins))
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93
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94 # Postfix code:
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95 for ins in self.epilogue():
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96 self.instructions.append(AbstractInstruction(ins))
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