Proper label generation in stack backend.
catseye
12 years ago
| 17 | 17 | class Compiler(object): |
| 18 | 18 | def __init__(self, out): |
| 19 | 19 | self.out = out |
| 20 | self.labels = {} | |
| 21 | self.current_loop_end = None | |
| 22 | ||
| 23 | def get_label(self, pref): | |
| 24 | count = self.labels.get(pref, 0) | |
| 25 | label = '%s_%d' % (pref, count) | |
| 26 | self.labels[pref] = count + 1 | |
| 27 | return label | |
| 20 | 28 | |
| 21 | 29 | def compile(self, ast): |
| 22 | 30 | if ast.type == 'Program': |
| 27 | 35 | for child in ast.children: |
| 28 | 36 | self.compile(child) |
| 29 | 37 | self.out.write("""\ |
| 38 | ; call main | |
| 39 | push main | |
| 40 | call | |
| 30 | 41 | """) |
| 31 | 42 | elif ast.type == 'Defn': |
| 32 | 43 | self.out.write('%s:\n' % ast.value) |
| 34 | 45 | elif ast.type in ('StructDefn', 'Forward'): |
| 35 | 46 | pass |
| 36 | 47 | elif ast.type == 'FunLit': |
| 37 | self.out.write('jmp next\n') | |
| 38 | self.out.write('funlit:\n') | |
| 48 | l = self.get_label('past_fun') | |
| 49 | self.out.write('jmp %s\n' % l) | |
| 50 | f = self.get_label('fun_lit') | |
| 51 | self.out.write('%s:\n' % f) | |
| 39 | 52 | self.compile(ast.children[0]) |
| 40 | 53 | self.compile(ast.children[1]) |
| 41 | self.out.write('push nil\n') | |
| 42 | self.out.write('rts\n') | |
| 54 | self.out.write('%s:\n' % l) | |
| 55 | self.out.write('push %s\n' % f) | |
| 43 | 56 | elif ast.type == 'Args': |
| 44 | 57 | for child in ast.children: |
| 45 | 58 | self.compile(child) |
| 52 | 65 | self.out.write('; push variable %s onto stack\n' % ast.value) |
| 53 | 66 | self.compile(ast.children[0]) |
| 54 | 67 | elif ast.type == 'While': |
| 55 | self.out.write('loop_start:\n') | |
| 68 | start = self.get_label('loop_start') | |
| 69 | end = self.get_label('loop_end') | |
| 70 | save = self.current_loop_end | |
| 71 | self.current_loop_end = end | |
| 72 | self.out.write('%s:\n' % start) | |
| 56 | 73 | self.compile(ast.children[0]) |
| 57 | self.out.write('beq loop_end\n') | |
| 74 | self.out.write('beq %s\n' % end) | |
| 58 | 75 | self.compile(ast.children[1]) |
| 59 | self.out.write('jmp loop_start\n') | |
| 60 | self.out.write('loop_end:\n') | |
| 76 | self.out.write('jmp %s\n' % start) | |
| 77 | self.out.write('%s:\n' % end) | |
| 78 | self.current_loop_end = self.current_loop_end | |
| 61 | 79 | elif ast.type == 'Op': |
| 62 | 80 | self.compile(ast.children[0]) |
| 63 | 81 | self.compile(ast.children[1]) |
| 72 | 90 | self.compile(ast.children[0]) |
| 73 | 91 | self.out.write('call\n') |
| 74 | 92 | elif ast.type == 'If': |
| 75 | #~ self.out.write('if (') | |
| 76 | #~ self.compile(ast.children[0]) | |
| 77 | #~ self.out.write(') then\n') | |
| 78 | #~ if len(ast.children) == 3: # if-else | |
| 79 | #~ self.compile(ast.children[1]) | |
| 80 | #~ self.out.write(' else\n') | |
| 81 | #~ self.compile(ast.children[2]) | |
| 82 | #~ else: # just-if | |
| 83 | #~ self.compile(ast.children[1]) | |
| 84 | #~ self.out.write('end\n') | |
| 85 | pass | |
| 93 | else_part = self.get_label('else_part') | |
| 94 | end_if = self.get_label('end_if') | |
| 95 | self.compile(ast.children[0]) | |
| 96 | self.out.write('beq %s\n' % else_part) | |
| 97 | self.compile(ast.children[1]) | |
| 98 | self.out.write('jmp %s\n' % end_if) | |
| 99 | self.out.write('%s:\n' % else_part) | |
| 100 | if len(ast.children) == 3: | |
| 101 | self.compile(ast.children[2]) | |
| 102 | self.out.write('%s:\n' % end_if) | |
| 86 | 103 | elif ast.type == 'Return': |
| 87 | 104 | self.compile(ast.children[0]) |
| 88 | 105 | self.out.write('rts\n') |
| 89 | 106 | elif ast.type == 'Break': |
| 90 | self.out.write('jmp loop_end\n') | |
| 107 | self.out.write('jmp %s\n' % self.current_loop_end) | |
| 91 | 108 | elif ast.type == 'Not': |
| 92 | 109 | self.compile(ast.children[0]) |
| 93 | 110 | self.out.write('not\n') |
| 95 | 112 | self.out.write('push nil\n') |
| 96 | 113 | elif ast.type == 'BoolLit': |
| 97 | 114 | if ast.value: |
| 98 | self.out.write("push true\n") | |
| 115 | self.out.write("push -1\n") | |
| 99 | 116 | else: |
| 100 | self.out.write("push false\n") | |
| 117 | self.out.write("push 0\n") | |
| 101 | 118 | elif ast.type == 'IntLit': |
| 102 | 119 | self.out.write('push %s\n' % ast.value) |
| 103 | 120 | elif ast.type == 'StrLit': |
| 104 | 121 | self.out.write('push %r\n' % ast.value) |
| 105 | 122 | elif ast.type == 'Assignment': |
| 106 | 123 | self.compile(ast.children[1]) |
| 107 | self.out.write('; assign to...') | |
| 124 | self.out.write('; assign to...\n') | |
| 108 | 125 | self.compile(ast.children[0]) |
| 126 | self.out.write('assign\n') | |
| 109 | 127 | elif ast.type == 'Make': |
| 110 | 128 | #~ self.out.write('{') |
| 111 | 129 | #~ self.commas(ast.children[1:]) |