/* constmrg.h: Routines to merge constants Copyright (C) 2004 Kevin Kofler This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef CONSTMRG_H #define CONSTMRG_H #include "generic.h" #include "data.h" // Merge constants (including strings) in sections marked Mergeable to avoid // duplication. A constant is considered to be an interval enclosed within 2 // label groups, where a label group is the equivalence class formed by the // symbols at a given offset. A constant is said unaligned if the section // containing it also has the Unaligned flag set, and aligned otherwise. The // value of a constant is said to be the contents of the interval defining it. // The algorithm used is a prefix merge algorithm: // * If the value of a constant A is a prefix of the value of a constant B, and // A is unaligned and/or B is aligned, then A is identified with B. // * If the value of a constant A is a strict prefix of the value of a constant // B, A is aligned and B is unaligned, then B is split into a new aligned // section, and A is identified with the so-created B. // Identification works the following way: The label group defining A is moved // into the label group defining B. Then, if A was constituting an entire // section, the section is deleted. Otherwise, A is removed using the // range-cutting API. // The linker doesn't look for identical constants in the same section. It is // the compiler's job to merge constants in this case. void MergeConstants (PROGRAM *Program); #endif