1 | /* Peephole optimizations for bytecode compiler. */
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2 |
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3 | #include "Python.h"
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4 |
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5 | #include "Python-ast.h"
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6 | #include "node.h"
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7 | #include "pyarena.h"
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8 | #include "ast.h"
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9 | #include "code.h"
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10 | #include "compile.h"
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11 | #include "symtable.h"
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12 | #include "opcode.h"
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13 |
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14 | #define GETARG(arr, i) ((int)((arr[i+2]<<8) + arr[i+1]))
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15 | #define UNCONDITIONAL_JUMP(op) (op==JUMP_ABSOLUTE || op==JUMP_FORWARD)
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16 | #define CONDITIONAL_JUMP(op) (op==POP_JUMP_IF_FALSE || op==POP_JUMP_IF_TRUE \
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17 | || op==JUMP_IF_FALSE_OR_POP || op==JUMP_IF_TRUE_OR_POP)
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18 | #define ABSOLUTE_JUMP(op) (op==JUMP_ABSOLUTE || op==CONTINUE_LOOP \
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19 | || op==POP_JUMP_IF_FALSE || op==POP_JUMP_IF_TRUE \
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20 | || op==JUMP_IF_FALSE_OR_POP || op==JUMP_IF_TRUE_OR_POP)
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21 | #define JUMPS_ON_TRUE(op) (op==POP_JUMP_IF_TRUE || op==JUMP_IF_TRUE_OR_POP)
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22 | #define GETJUMPTGT(arr, i) (GETARG(arr,i) + (ABSOLUTE_JUMP(arr[i]) ? 0 : i+3))
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23 | #define SETARG(arr, i, val) arr[i+2] = val>>8; arr[i+1] = val & 255
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24 | #define CODESIZE(op) (HAS_ARG(op) ? 3 : 1)
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25 | #define ISBASICBLOCK(blocks, start, bytes) \
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26 | (blocks[start]==blocks[start+bytes-1])
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27 |
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28 | /* Replace LOAD_CONST c1. LOAD_CONST c2 ... LOAD_CONST cn BUILD_TUPLE n
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29 | with LOAD_CONST (c1, c2, ... cn).
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30 | The consts table must still be in list form so that the
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31 | new constant (c1, c2, ... cn) can be appended.
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32 | Called with codestr pointing to the first LOAD_CONST.
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33 | Bails out with no change if one or more of the LOAD_CONSTs is missing.
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34 | Also works for BUILD_LIST when followed by an "in" or "not in" test.
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35 | */
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36 | static int
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37 | tuple_of_constants(unsigned char *codestr, Py_ssize_t n, PyObject *consts)
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38 | {
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39 | PyObject *newconst, *constant;
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40 | Py_ssize_t i, arg, len_consts;
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41 |
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42 | /* Pre-conditions */
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43 | assert(PyList_CheckExact(consts));
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44 | assert(codestr[n*3] == BUILD_TUPLE || codestr[n*3] == BUILD_LIST);
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45 | assert(GETARG(codestr, (n*3)) == n);
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46 | for (i=0 ; i<n ; i++)
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47 | assert(codestr[i*3] == LOAD_CONST);
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48 |
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49 | /* Buildup new tuple of constants */
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50 | newconst = PyTuple_New(n);
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51 | if (newconst == NULL)
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52 | return 0;
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53 | len_consts = PyList_GET_SIZE(consts);
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54 | for (i=0 ; i<n ; i++) {
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55 | arg = GETARG(codestr, (i*3));
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56 | assert(arg < len_consts);
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57 | constant = PyList_GET_ITEM(consts, arg);
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58 | Py_INCREF(constant);
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59 | PyTuple_SET_ITEM(newconst, i, constant);
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60 | }
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61 |
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62 | /* Append folded constant onto consts */
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63 | if (PyList_Append(consts, newconst)) {
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64 | Py_DECREF(newconst);
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65 | return 0;
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66 | }
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67 | Py_DECREF(newconst);
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68 |
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69 | /* Write NOPs over old LOAD_CONSTS and
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70 | add a new LOAD_CONST newconst on top of the BUILD_TUPLE n */
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71 | memset(codestr, NOP, n*3);
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72 | codestr[n*3] = LOAD_CONST;
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73 | SETARG(codestr, (n*3), len_consts);
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74 | return 1;
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75 | }
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76 |
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77 | /* Replace LOAD_CONST c1. LOAD_CONST c2 BINOP
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78 | with LOAD_CONST binop(c1,c2)
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79 | The consts table must still be in list form so that the
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80 | new constant can be appended.
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81 | Called with codestr pointing to the first LOAD_CONST.
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82 | Abandons the transformation if the folding fails (i.e. 1+'a').
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83 | If the new constant is a sequence, only folds when the size
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84 | is below a threshold value. That keeps pyc files from
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85 | becoming large in the presence of code like: (None,)*1000.
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86 | */
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87 | static int
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88 | fold_binops_on_constants(unsigned char *codestr, PyObject *consts)
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89 | {
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90 | PyObject *newconst, *v, *w;
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91 | Py_ssize_t len_consts, size;
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92 | int opcode;
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93 |
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94 | /* Pre-conditions */
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95 | assert(PyList_CheckExact(consts));
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96 | assert(codestr[0] == LOAD_CONST);
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97 | assert(codestr[3] == LOAD_CONST);
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98 |
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99 | /* Create new constant */
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100 | v = PyList_GET_ITEM(consts, GETARG(codestr, 0));
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101 | w = PyList_GET_ITEM(consts, GETARG(codestr, 3));
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102 | opcode = codestr[6];
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103 | switch (opcode) {
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104 | case BINARY_POWER:
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105 | newconst = PyNumber_Power(v, w, Py_None);
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106 | break;
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107 | case BINARY_MULTIPLY:
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108 | newconst = PyNumber_Multiply(v, w);
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109 | break;
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110 | case BINARY_DIVIDE:
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111 | /* Cannot fold this operation statically since
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112 | the result can depend on the run-time presence
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113 | of the -Qnew flag */
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114 | return 0;
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115 | case BINARY_TRUE_DIVIDE:
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116 | newconst = PyNumber_TrueDivide(v, w);
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117 | break;
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118 | case BINARY_FLOOR_DIVIDE:
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119 | newconst = PyNumber_FloorDivide(v, w);
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120 | break;
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121 | case BINARY_MODULO:
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122 | newconst = PyNumber_Remainder(v, w);
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123 | break;
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124 | case BINARY_ADD:
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125 | newconst = PyNumber_Add(v, w);
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126 | break;
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127 | case BINARY_SUBTRACT:
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128 | newconst = PyNumber_Subtract(v, w);
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129 | break;
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130 | case BINARY_SUBSCR:
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131 | /* #5057: if v is unicode, there might be differences between
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132 | wide and narrow builds in cases like '\U00012345'[0] or
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133 | '\U00012345abcdef'[3], so it's better to skip the optimization
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134 | in order to produce compatible pycs.
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135 | */
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136 | if (PyUnicode_Check(v))
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137 | return 0;
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138 | newconst = PyObject_GetItem(v, w);
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139 | break;
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140 | case BINARY_LSHIFT:
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141 | newconst = PyNumber_Lshift(v, w);
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142 | break;
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143 | case BINARY_RSHIFT:
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144 | newconst = PyNumber_Rshift(v, w);
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145 | break;
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146 | case BINARY_AND:
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147 | newconst = PyNumber_And(v, w);
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148 | break;
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149 | case BINARY_XOR:
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150 | newconst = PyNumber_Xor(v, w);
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151 | break;
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152 | case BINARY_OR:
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153 | newconst = PyNumber_Or(v, w);
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154 | break;
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155 | default:
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156 | /* Called with an unknown opcode */
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157 | PyErr_Format(PyExc_SystemError,
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158 | "unexpected binary operation %d on a constant",
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159 | opcode);
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160 | return 0;
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161 | }
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162 | if (newconst == NULL) {
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163 | PyErr_Clear();
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164 | return 0;
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165 | }
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166 | size = PyObject_Size(newconst);
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167 | if (size == -1)
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168 | PyErr_Clear();
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169 | else if (size > 20) {
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170 | Py_DECREF(newconst);
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171 | return 0;
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172 | }
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173 |
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174 | /* Append folded constant into consts table */
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175 | len_consts = PyList_GET_SIZE(consts);
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176 | if (PyList_Append(consts, newconst)) {
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177 | Py_DECREF(newconst);
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178 | return 0;
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179 | }
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180 | Py_DECREF(newconst);
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181 |
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182 | /* Write NOP NOP NOP NOP LOAD_CONST newconst */
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183 | memset(codestr, NOP, 4);
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184 | codestr[4] = LOAD_CONST;
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185 | SETARG(codestr, 4, len_consts);
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186 | return 1;
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187 | }
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188 |
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189 | static int
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190 | fold_unaryops_on_constants(unsigned char *codestr, PyObject *consts)
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191 | {
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192 | PyObject *newconst=NULL, *v;
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193 | Py_ssize_t len_consts;
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194 | int opcode;
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195 |
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196 | /* Pre-conditions */
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197 | assert(PyList_CheckExact(consts));
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198 | assert(codestr[0] == LOAD_CONST);
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199 |
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200 | /* Create new constant */
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201 | v = PyList_GET_ITEM(consts, GETARG(codestr, 0));
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202 | opcode = codestr[3];
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203 | switch (opcode) {
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204 | case UNARY_NEGATIVE:
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205 | /* Preserve the sign of -0.0 */
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206 | if (PyObject_IsTrue(v) == 1)
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207 | newconst = PyNumber_Negative(v);
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208 | break;
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209 | case UNARY_CONVERT:
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210 | newconst = PyObject_Repr(v);
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211 | break;
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212 | case UNARY_INVERT:
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213 | newconst = PyNumber_Invert(v);
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214 | break;
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215 | default:
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216 | /* Called with an unknown opcode */
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217 | PyErr_Format(PyExc_SystemError,
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218 | "unexpected unary operation %d on a constant",
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219 | opcode);
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220 | return 0;
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221 | }
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222 | if (newconst == NULL) {
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223 | PyErr_Clear();
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224 | return 0;
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225 | }
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226 |
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227 | /* Append folded constant into consts table */
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228 | len_consts = PyList_GET_SIZE(consts);
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229 | if (PyList_Append(consts, newconst)) {
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230 | Py_DECREF(newconst);
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231 | return 0;
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232 | }
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233 | Py_DECREF(newconst);
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234 |
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235 | /* Write NOP LOAD_CONST newconst */
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236 | codestr[0] = NOP;
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237 | codestr[1] = LOAD_CONST;
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238 | SETARG(codestr, 1, len_consts);
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239 | return 1;
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240 | }
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241 |
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242 | static unsigned int *
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243 | markblocks(unsigned char *code, Py_ssize_t len)
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244 | {
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245 | unsigned int *blocks = (unsigned int *)PyMem_Malloc(len*sizeof(int));
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246 | int i,j, opcode, blockcnt = 0;
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247 |
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248 | if (blocks == NULL) {
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249 | PyErr_NoMemory();
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250 | return NULL;
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251 | }
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252 | memset(blocks, 0, len*sizeof(int));
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253 |
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254 | /* Mark labels in the first pass */
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255 | for (i=0 ; i<len ; i+=CODESIZE(opcode)) {
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256 | opcode = code[i];
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257 | switch (opcode) {
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258 | case FOR_ITER:
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259 | case JUMP_FORWARD:
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260 | case JUMP_IF_FALSE_OR_POP:
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261 | case JUMP_IF_TRUE_OR_POP:
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262 | case POP_JUMP_IF_FALSE:
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263 | case POP_JUMP_IF_TRUE:
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264 | case JUMP_ABSOLUTE:
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265 | case CONTINUE_LOOP:
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266 | case SETUP_LOOP:
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267 | case SETUP_EXCEPT:
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268 | case SETUP_FINALLY:
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269 | case SETUP_WITH:
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270 | j = GETJUMPTGT(code, i);
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271 | blocks[j] = 1;
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272 | break;
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273 | }
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274 | }
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275 | /* Build block numbers in the second pass */
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276 | for (i=0 ; i<len ; i++) {
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277 | blockcnt += blocks[i]; /* increment blockcnt over labels */
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278 | blocks[i] = blockcnt;
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279 | }
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280 | return blocks;
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281 | }
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282 |
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283 | /* Perform basic peephole optimizations to components of a code object.
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284 | The consts object should still be in list form to allow new constants
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285 | to be appended.
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286 |
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287 | To keep the optimizer simple, it bails out (does nothing) for code
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288 | containing extended arguments or that has a length over 32,700. That
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289 | allows us to avoid overflow and sign issues. Likewise, it bails when
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290 | the lineno table has complex encoding for gaps >= 255.
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291 |
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292 | Optimizations are restricted to simple transformations occuring within a
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293 | single basic block. All transformations keep the code size the same or
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294 | smaller. For those that reduce size, the gaps are initially filled with
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295 | NOPs. Later those NOPs are removed and the jump addresses retargeted in
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296 | a single pass. Line numbering is adjusted accordingly. */
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297 |
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298 | PyObject *
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299 | PyCode_Optimize(PyObject *code, PyObject* consts, PyObject *names,
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300 | PyObject *lineno_obj)
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301 | {
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302 | Py_ssize_t i, j, codelen;
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303 | int nops, h, adj;
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304 | int tgt, tgttgt, opcode;
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305 | unsigned char *codestr = NULL;
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306 | unsigned char *lineno;
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307 | int *addrmap = NULL;
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308 | int new_line, cum_orig_line, last_line, tabsiz;
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309 | int cumlc=0, lastlc=0; /* Count runs of consecutive LOAD_CONSTs */
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310 | unsigned int *blocks = NULL;
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311 | char *name;
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312 |
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313 | /* Bail out if an exception is set */
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314 | if (PyErr_Occurred())
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315 | goto exitError;
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316 |
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317 | /* Bypass optimization when the lineno table is too complex */
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318 | assert(PyString_Check(lineno_obj));
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319 | lineno = (unsigned char*)PyString_AS_STRING(lineno_obj);
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320 | tabsiz = PyString_GET_SIZE(lineno_obj);
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321 | if (memchr(lineno, 255, tabsiz) != NULL)
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322 | goto exitUnchanged;
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323 |
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324 | /* Avoid situations where jump retargeting could overflow */
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325 | assert(PyString_Check(code));
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326 | codelen = PyString_GET_SIZE(code);
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327 | if (codelen > 32700)
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328 | goto exitUnchanged;
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329 |
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330 | /* Make a modifiable copy of the code string */
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331 | codestr = (unsigned char *)PyMem_Malloc(codelen);
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332 | if (codestr == NULL)
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333 | goto exitError;
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334 | codestr = (unsigned char *)memcpy(codestr,
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335 | PyString_AS_STRING(code), codelen);
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336 |
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337 | /* Verify that RETURN_VALUE terminates the codestring. This allows
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338 | the various transformation patterns to look ahead several
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339 | instructions without additional checks to make sure they are not
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340 | looking beyond the end of the code string.
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341 | */
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342 | if (codestr[codelen-1] != RETURN_VALUE)
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343 | goto exitUnchanged;
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344 |
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345 | /* Mapping to new jump targets after NOPs are removed */
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346 | addrmap = (int *)PyMem_Malloc(codelen * sizeof(int));
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347 | if (addrmap == NULL)
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348 | goto exitError;
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349 |
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350 | blocks = markblocks(codestr, codelen);
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351 | if (blocks == NULL)
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352 | goto exitError;
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353 | assert(PyList_Check(consts));
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354 |
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355 | for (i=0 ; i<codelen ; i += CODESIZE(codestr[i])) {
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356 | reoptimize_current:
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357 | opcode = codestr[i];
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358 |
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359 | lastlc = cumlc;
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360 | cumlc = 0;
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361 |
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362 | switch (opcode) {
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363 | /* Replace UNARY_NOT POP_JUMP_IF_FALSE
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364 | with POP_JUMP_IF_TRUE */
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365 | case UNARY_NOT:
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366 | if (codestr[i+1] != POP_JUMP_IF_FALSE
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367 | || !ISBASICBLOCK(blocks,i,4))
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368 | continue;
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369 | j = GETARG(codestr, i+1);
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370 | codestr[i] = POP_JUMP_IF_TRUE;
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371 | SETARG(codestr, i, j);
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372 | codestr[i+3] = NOP;
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373 | goto reoptimize_current;
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374 |
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375 | /* not a is b --> a is not b
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376 | not a in b --> a not in b
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377 | not a is not b --> a is b
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378 | not a not in b --> a in b
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379 | */
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380 | case COMPARE_OP:
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381 | j = GETARG(codestr, i);
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382 | if (j < 6 || j > 9 ||
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383 | codestr[i+3] != UNARY_NOT ||
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384 | !ISBASICBLOCK(blocks,i,4))
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385 | continue;
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386 | SETARG(codestr, i, (j^1));
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387 | codestr[i+3] = NOP;
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388 | break;
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389 |
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390 | /* Replace LOAD_GLOBAL/LOAD_NAME None
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391 | with LOAD_CONST None */
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392 | case LOAD_NAME:
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393 | case LOAD_GLOBAL:
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394 | j = GETARG(codestr, i);
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395 | name = PyString_AsString(PyTuple_GET_ITEM(names, j));
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396 | if (name == NULL || strcmp(name, "None") != 0)
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397 | continue;
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398 | for (j=0 ; j < PyList_GET_SIZE(consts) ; j++) {
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399 | if (PyList_GET_ITEM(consts, j) == Py_None)
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400 | break;
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401 | }
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402 | if (j == PyList_GET_SIZE(consts)) {
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403 | if (PyList_Append(consts, Py_None) == -1)
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404 | goto exitError;
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405 | }
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406 | assert(PyList_GET_ITEM(consts, j) == Py_None);
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407 | codestr[i] = LOAD_CONST;
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408 | SETARG(codestr, i, j);
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409 | cumlc = lastlc + 1;
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410 | break;
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411 |
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412 | /* Skip over LOAD_CONST trueconst
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413 | POP_JUMP_IF_FALSE xx. This improves
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414 | "while 1" performance. */
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415 | case LOAD_CONST:
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416 | cumlc = lastlc + 1;
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417 | j = GETARG(codestr, i);
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418 | if (codestr[i+3] != POP_JUMP_IF_FALSE ||
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419 | !ISBASICBLOCK(blocks,i,6) ||
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420 | !PyObject_IsTrue(PyList_GET_ITEM(consts, j)))
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421 | continue;
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422 | memset(codestr+i, NOP, 6);
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423 | cumlc = 0;
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424 | break;
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425 |
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426 | /* Try to fold tuples of constants (includes a case for lists
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427 | which are only used for "in" and "not in" tests).
|
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428 | Skip over BUILD_SEQN 1 UNPACK_SEQN 1.
|
---|
429 | Replace BUILD_SEQN 2 UNPACK_SEQN 2 with ROT2.
|
---|
430 | Replace BUILD_SEQN 3 UNPACK_SEQN 3 with ROT3 ROT2. */
|
---|
431 | case BUILD_TUPLE:
|
---|
432 | case BUILD_LIST:
|
---|
433 | j = GETARG(codestr, i);
|
---|
434 | h = i - 3 * j;
|
---|
435 | if (h >= 0 &&
|
---|
436 | j <= lastlc &&
|
---|
437 | ((opcode == BUILD_TUPLE &&
|
---|
438 | ISBASICBLOCK(blocks, h, 3*(j+1))) ||
|
---|
439 | (opcode == BUILD_LIST &&
|
---|
440 | codestr[i+3]==COMPARE_OP &&
|
---|
441 | ISBASICBLOCK(blocks, h, 3*(j+2)) &&
|
---|
442 | (GETARG(codestr,i+3)==6 ||
|
---|
443 | GETARG(codestr,i+3)==7))) &&
|
---|
444 | tuple_of_constants(&codestr[h], j, consts)) {
|
---|
445 | assert(codestr[i] == LOAD_CONST);
|
---|
446 | cumlc = 1;
|
---|
447 | break;
|
---|
448 | }
|
---|
449 | if (codestr[i+3] != UNPACK_SEQUENCE ||
|
---|
450 | !ISBASICBLOCK(blocks,i,6) ||
|
---|
451 | j != GETARG(codestr, i+3))
|
---|
452 | continue;
|
---|
453 | if (j == 1) {
|
---|
454 | memset(codestr+i, NOP, 6);
|
---|
455 | } else if (j == 2) {
|
---|
456 | codestr[i] = ROT_TWO;
|
---|
457 | memset(codestr+i+1, NOP, 5);
|
---|
458 | } else if (j == 3) {
|
---|
459 | codestr[i] = ROT_THREE;
|
---|
460 | codestr[i+1] = ROT_TWO;
|
---|
461 | memset(codestr+i+2, NOP, 4);
|
---|
462 | }
|
---|
463 | break;
|
---|
464 |
|
---|
465 | /* Fold binary ops on constants.
|
---|
466 | LOAD_CONST c1 LOAD_CONST c2 BINOP --> LOAD_CONST binop(c1,c2) */
|
---|
467 | case BINARY_POWER:
|
---|
468 | case BINARY_MULTIPLY:
|
---|
469 | case BINARY_TRUE_DIVIDE:
|
---|
470 | case BINARY_FLOOR_DIVIDE:
|
---|
471 | case BINARY_MODULO:
|
---|
472 | case BINARY_ADD:
|
---|
473 | case BINARY_SUBTRACT:
|
---|
474 | case BINARY_SUBSCR:
|
---|
475 | case BINARY_LSHIFT:
|
---|
476 | case BINARY_RSHIFT:
|
---|
477 | case BINARY_AND:
|
---|
478 | case BINARY_XOR:
|
---|
479 | case BINARY_OR:
|
---|
480 | if (lastlc >= 2 &&
|
---|
481 | ISBASICBLOCK(blocks, i-6, 7) &&
|
---|
482 | fold_binops_on_constants(&codestr[i-6], consts)) {
|
---|
483 | i -= 2;
|
---|
484 | assert(codestr[i] == LOAD_CONST);
|
---|
485 | cumlc = 1;
|
---|
486 | }
|
---|
487 | break;
|
---|
488 |
|
---|
489 | /* Fold unary ops on constants.
|
---|
490 | LOAD_CONST c1 UNARY_OP --> LOAD_CONST unary_op(c) */
|
---|
491 | case UNARY_NEGATIVE:
|
---|
492 | case UNARY_CONVERT:
|
---|
493 | case UNARY_INVERT:
|
---|
494 | if (lastlc >= 1 &&
|
---|
495 | ISBASICBLOCK(blocks, i-3, 4) &&
|
---|
496 | fold_unaryops_on_constants(&codestr[i-3], consts)) {
|
---|
497 | i -= 2;
|
---|
498 | assert(codestr[i] == LOAD_CONST);
|
---|
499 | cumlc = 1;
|
---|
500 | }
|
---|
501 | break;
|
---|
502 |
|
---|
503 | /* Simplify conditional jump to conditional jump where the
|
---|
504 | result of the first test implies the success of a similar
|
---|
505 | test or the failure of the opposite test.
|
---|
506 | Arises in code like:
|
---|
507 | "if a and b:"
|
---|
508 | "if a or b:"
|
---|
509 | "a and b or c"
|
---|
510 | "(a and b) and c"
|
---|
511 | x:JUMP_IF_FALSE_OR_POP y y:JUMP_IF_FALSE_OR_POP z
|
---|
512 | --> x:JUMP_IF_FALSE_OR_POP z
|
---|
513 | x:JUMP_IF_FALSE_OR_POP y y:JUMP_IF_TRUE_OR_POP z
|
---|
514 | --> x:POP_JUMP_IF_FALSE y+3
|
---|
515 | where y+3 is the instruction following the second test.
|
---|
516 | */
|
---|
517 | case JUMP_IF_FALSE_OR_POP:
|
---|
518 | case JUMP_IF_TRUE_OR_POP:
|
---|
519 | tgt = GETJUMPTGT(codestr, i);
|
---|
520 | j = codestr[tgt];
|
---|
521 | if (CONDITIONAL_JUMP(j)) {
|
---|
522 | /* NOTE: all possible jumps here are absolute! */
|
---|
523 | if (JUMPS_ON_TRUE(j) == JUMPS_ON_TRUE(opcode)) {
|
---|
524 | /* The second jump will be
|
---|
525 | taken iff the first is. */
|
---|
526 | tgttgt = GETJUMPTGT(codestr, tgt);
|
---|
527 | /* The current opcode inherits
|
---|
528 | its target's stack behaviour */
|
---|
529 | codestr[i] = j;
|
---|
530 | SETARG(codestr, i, tgttgt);
|
---|
531 | goto reoptimize_current;
|
---|
532 | } else {
|
---|
533 | /* The second jump is not taken if the first is (so
|
---|
534 | jump past it), and all conditional jumps pop their
|
---|
535 | argument when they're not taken (so change the
|
---|
536 | first jump to pop its argument when it's taken). */
|
---|
537 | if (JUMPS_ON_TRUE(opcode))
|
---|
538 | codestr[i] = POP_JUMP_IF_TRUE;
|
---|
539 | else
|
---|
540 | codestr[i] = POP_JUMP_IF_FALSE;
|
---|
541 | SETARG(codestr, i, (tgt + 3));
|
---|
542 | goto reoptimize_current;
|
---|
543 | }
|
---|
544 | }
|
---|
545 | /* Intentional fallthrough */
|
---|
546 |
|
---|
547 | /* Replace jumps to unconditional jumps */
|
---|
548 | case POP_JUMP_IF_FALSE:
|
---|
549 | case POP_JUMP_IF_TRUE:
|
---|
550 | case FOR_ITER:
|
---|
551 | case JUMP_FORWARD:
|
---|
552 | case JUMP_ABSOLUTE:
|
---|
553 | case CONTINUE_LOOP:
|
---|
554 | case SETUP_LOOP:
|
---|
555 | case SETUP_EXCEPT:
|
---|
556 | case SETUP_FINALLY:
|
---|
557 | case SETUP_WITH:
|
---|
558 | tgt = GETJUMPTGT(codestr, i);
|
---|
559 | /* Replace JUMP_* to a RETURN into just a RETURN */
|
---|
560 | if (UNCONDITIONAL_JUMP(opcode) &&
|
---|
561 | codestr[tgt] == RETURN_VALUE) {
|
---|
562 | codestr[i] = RETURN_VALUE;
|
---|
563 | memset(codestr+i+1, NOP, 2);
|
---|
564 | continue;
|
---|
565 | }
|
---|
566 | if (!UNCONDITIONAL_JUMP(codestr[tgt]))
|
---|
567 | continue;
|
---|
568 | tgttgt = GETJUMPTGT(codestr, tgt);
|
---|
569 | if (opcode == JUMP_FORWARD) /* JMP_ABS can go backwards */
|
---|
570 | opcode = JUMP_ABSOLUTE;
|
---|
571 | if (!ABSOLUTE_JUMP(opcode))
|
---|
572 | tgttgt -= i + 3; /* Calc relative jump addr */
|
---|
573 | if (tgttgt < 0) /* No backward relative jumps */
|
---|
574 | continue;
|
---|
575 | codestr[i] = opcode;
|
---|
576 | SETARG(codestr, i, tgttgt);
|
---|
577 | break;
|
---|
578 |
|
---|
579 | case EXTENDED_ARG:
|
---|
580 | goto exitUnchanged;
|
---|
581 |
|
---|
582 | /* Replace RETURN LOAD_CONST None RETURN with just RETURN */
|
---|
583 | /* Remove unreachable JUMPs after RETURN */
|
---|
584 | case RETURN_VALUE:
|
---|
585 | if (i+4 >= codelen)
|
---|
586 | continue;
|
---|
587 | if (codestr[i+4] == RETURN_VALUE &&
|
---|
588 | ISBASICBLOCK(blocks,i,5))
|
---|
589 | memset(codestr+i+1, NOP, 4);
|
---|
590 | else if (UNCONDITIONAL_JUMP(codestr[i+1]) &&
|
---|
591 | ISBASICBLOCK(blocks,i,4))
|
---|
592 | memset(codestr+i+1, NOP, 3);
|
---|
593 | break;
|
---|
594 | }
|
---|
595 | }
|
---|
596 |
|
---|
597 | /* Fixup linenotab */
|
---|
598 | for (i=0, nops=0 ; i<codelen ; i += CODESIZE(codestr[i])) {
|
---|
599 | addrmap[i] = i - nops;
|
---|
600 | if (codestr[i] == NOP)
|
---|
601 | nops++;
|
---|
602 | }
|
---|
603 | cum_orig_line = 0;
|
---|
604 | last_line = 0;
|
---|
605 | for (i=0 ; i < tabsiz ; i+=2) {
|
---|
606 | cum_orig_line += lineno[i];
|
---|
607 | new_line = addrmap[cum_orig_line];
|
---|
608 | assert (new_line - last_line < 255);
|
---|
609 | lineno[i] =((unsigned char)(new_line - last_line));
|
---|
610 | last_line = new_line;
|
---|
611 | }
|
---|
612 |
|
---|
613 | /* Remove NOPs and fixup jump targets */
|
---|
614 | for (i=0, h=0 ; i<codelen ; ) {
|
---|
615 | opcode = codestr[i];
|
---|
616 | switch (opcode) {
|
---|
617 | case NOP:
|
---|
618 | i++;
|
---|
619 | continue;
|
---|
620 |
|
---|
621 | case JUMP_ABSOLUTE:
|
---|
622 | case CONTINUE_LOOP:
|
---|
623 | case POP_JUMP_IF_FALSE:
|
---|
624 | case POP_JUMP_IF_TRUE:
|
---|
625 | case JUMP_IF_FALSE_OR_POP:
|
---|
626 | case JUMP_IF_TRUE_OR_POP:
|
---|
627 | j = addrmap[GETARG(codestr, i)];
|
---|
628 | SETARG(codestr, i, j);
|
---|
629 | break;
|
---|
630 |
|
---|
631 | case FOR_ITER:
|
---|
632 | case JUMP_FORWARD:
|
---|
633 | case SETUP_LOOP:
|
---|
634 | case SETUP_EXCEPT:
|
---|
635 | case SETUP_FINALLY:
|
---|
636 | case SETUP_WITH:
|
---|
637 | j = addrmap[GETARG(codestr, i) + i + 3] - addrmap[i] - 3;
|
---|
638 | SETARG(codestr, i, j);
|
---|
639 | break;
|
---|
640 | }
|
---|
641 | adj = CODESIZE(opcode);
|
---|
642 | while (adj--)
|
---|
643 | codestr[h++] = codestr[i++];
|
---|
644 | }
|
---|
645 | assert(h + nops == codelen);
|
---|
646 |
|
---|
647 | code = PyString_FromStringAndSize((char *)codestr, h);
|
---|
648 | PyMem_Free(addrmap);
|
---|
649 | PyMem_Free(codestr);
|
---|
650 | PyMem_Free(blocks);
|
---|
651 | return code;
|
---|
652 |
|
---|
653 | exitError:
|
---|
654 | code = NULL;
|
---|
655 |
|
---|
656 | exitUnchanged:
|
---|
657 | if (blocks != NULL)
|
---|
658 | PyMem_Free(blocks);
|
---|
659 | if (addrmap != NULL)
|
---|
660 | PyMem_Free(addrmap);
|
---|
661 | if (codestr != NULL)
|
---|
662 | PyMem_Free(codestr);
|
---|
663 | Py_XINCREF(code);
|
---|
664 | return code;
|
---|
665 | }
|
---|