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Language_002ddependent-trees.html 4.3KB

3 年之前
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  68. <h3 class="section">11.9 Language-dependent trees</h3>
  69. <a name="index-language_002ddependent-trees"></a>
  70. <p>Front ends may wish to keep some state associated with various GENERIC
  71. trees while parsing. To support this, trees provide a set of flags
  72. that may be used by the front end. They are accessed using
  73. <code>TREE_LANG_FLAG_n</code> where &lsquo;<samp>n</samp>&rsquo; is currently 0 through 6.
  74. </p>
  75. <p>If necessary, a front end can use some language-dependent tree
  76. codes in its GENERIC representation, so long as it provides a
  77. hook for converting them to GIMPLE and doesn&rsquo;t expect them to
  78. work with any (hypothetical) optimizers that run before the
  79. conversion to GIMPLE. The intermediate representation used while
  80. parsing C and C++ looks very little like GENERIC, but the C and
  81. C++ gimplifier hooks are perfectly happy to take it as input and
  82. spit out GIMPLE.
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