html/suif1_86.html

   1 <HTML>
   2 <HEAD>
   3 <!-- This HTML file has been created by texi2html 1.54
   4      from suif1.texi on 28 April 1999 -->
   5
   6 <TITLE>The SUIF Version 1 Library - Finding Exposed References</TITLE>
   7 <link href="suif1_87.html" rel=Next>
   8 <link href="suif1_85.html" rel=Previous>
   9 <link href="suif1_toc.html" rel=ToC>
  10
  11 </HEAD>
  12 <BODY>
  13 <p>Go to the <A HREF="suif1_1.html">first</A>, <A HREF="suif1_85.html">previous</A>, <A HREF="suif1_87.html">next</A>, <A HREF="suif1_113.html">last</A> section, <A HREF="suif1_toc.html">table of contents</A>.
  14 <P><HR><P>
  15
  16
  17 <H2><A NAME="SEC86" HREF="suif1_toc.html#TOC86">Finding Exposed References</A></H2>
  18
  19 <P>
  20 <A NAME="IDX634"></A>
  21 <A NAME="IDX635"></A>
  22 <A NAME="IDX636"></A>
  23 <A NAME="IDX637"></A>
  24 <A NAME="IDX638"></A>
  25 The first step in the cloning process is to scan through the code being
  26 copied to search for references to objects that are not visible in the
  27 destination scope.  The <CODE>tree_node_list</CODE>, <CODE>tree_node</CODE>,
  28 <CODE>operand</CODE>, <CODE>instruction</CODE>, and <CODE>block_symtab</CODE> classes have
  29 <CODE>find_exposed_refs</CODE> methods to perform this operation.  The results
  30 are returned in a <CODE>replacements</CODE> structure by putting the exposed
  31 references in the lists of original objects.  The lists of new objects
  32 are left empty.
  33
  34 </P>
  35 <P>
  36 <A NAME="IDX639"></A>
  37 Besides checking for exposed references in the objects themselves, the
  38 <CODE>find_exposed_refs</CODE> methods also check for references contained in
  39 annotations attached to the objects.  Both flat and structured
  40 annotations are checked, but unregistered annotations are ignored since
  41 they are not copied.  The <CODE>find_annote_refs</CODE> method is used to
  42 check a <CODE>suif_object</CODE> for exposed references.
  43
  44 </P>
  45 <P>
  46 Label symbols are a special case.  Even if a label symbol is visible in
  47 the destination scope, it must be replaced if the label instruction is
  48 to be cloned.  Otherwise, there would be two label instructions sharing
  49 the same label symbol!  Thus, the <CODE>find_exposed_refs</CODE> method adds
  50 the symbol in a label instruction to the list of exposed references.
  51 The exception to this is that label symbols that are defined within
  52 cloned symbol tables will automatically be replaced and are not included
  53 in the exposed references.
  54
  55 </P>
  56
  57 <P><HR><P>
  58 <p>Go to the <A HREF="suif1_1.html">first</A>, <A HREF="suif1_85.html">previous</A>, <A HREF="suif1_87.html">next</A>, <A HREF="suif1_113.html">last</A> section, <A HREF="suif1_toc.html">table of contents</A>.
  59 </BODY>
  60 </HTML>