mingw/info/stabs/Source-Files.html

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  18
  19 <h3 class="section">Paths and Names of the Source Files</h3>
  20
  21    <p>Before any other stabs occur, there must be a stab specifying the source
  22 file.  This information is contained in a symbol of stab type
  23 <code>N_SO</code>; the string field contains the name of the file.  The
  24 value of the symbol is the start address of the portion of the
  25 text section corresponding to that file.
  26
  27    <p>With the Sun Solaris2 compiler, the desc field contains a
  28 source-language code.
  29
  30    <p>Some compilers (for example, GCC2 and SunOS4 <code>/bin/cc</code>) also
  31 include the directory in which the source was compiled, in a second
  32 <code>N_SO</code> symbol preceding the one containing the file name.  This
  33 symbol can be distinguished by the fact that it ends in a slash.  Code
  34 from the <code>cfront</code> C++ compiler can have additional <code>N_SO</code> symbols for
  35 nonexistent source files after the <code>N_SO</code> for the real source file;
  36 these are believed to contain no useful information.
  37
  38    <p>For example:
  39
  40 <pre class="example">     .stabs "/cygint/s1/users/jcm/play/",100,0,0,Ltext0     # 100 is N_SO
  41      .stabs "hello.c",100,0,0,Ltext0
  42              .text
  43      Ltext0:
  44      </pre>
  45
  46    <p>Instead of <code>N_SO</code> symbols, XCOFF uses a <code>.file</code> assembler
  47 directive which assembles to a <code>C_FILE</code> symbol; explaining this in
  48 detail is outside the scope of this document.
  49
  50    <p>If it is useful to indicate the end of a source file, this is done with
  51 an <code>N_SO</code> symbol with an empty string for the name.  The value is
  52 the address of the end of the text section for the file.  For some
  53 systems, there is no indication of the end of a source file, and you
  54 just need to figure it ended when you see an <code>N_SO</code> for a different
  55 source file, or a symbol ending in <code>.o</code> (which at least some
  56 linkers insert to mark the start of a new <code>.o</code> file).
  57
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