Improve comments, add the copyright notice

git-svn-id: svn://svn.valgrind.org/vex/trunk@3115

diff --git a/VEX/priv/multiarch_main_main.c b/VEX/priv/multiarch_main_main.c
index 8991e4525e599622331c219490e76ef68f183294..f2f2ed2c973d46291892440ba8ab8e4a3d3be7c6 100644 (file)
--- a/VEX/priv/multiarch_main_main.c
+++ b/VEX/priv/multiarch_main_main.c
@@ -1,2 +1,69 @@
+/*---------------------------------------------------------------*/
+/*--- Begin                             multiarch_main_main.c ---*/
+/*---------------------------------------------------------------*/
+
+/*
+   This file is part of Valgrind, a dynamic binary instrumentation
+   framework.
+
+   Copyright (C) 2015 Philippe Waroquiers
+
+   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 of the
+   License, 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., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301, USA.
+
+   The GNU General Public License is contained in the file COPYING.
+
+   Neither the names of the U.S. Department of Energy nor the
+   University of California nor the names of its contributors may be
+   used to endorse or promote products derived from this software
+   without prior written permission.
+*/
+
+/* This file is used to have main_main.c compiled with VEXMULTIARCH
+   defined, so that all host and guest arch are callable from LibVEX_Translate
+   and other functions defined in main_main.c.
+   The resulting object file will be put in libvexmultiarch-<platform>-os>.a.
+
+   The valgrind tools are making the assumption that host and guest are
+   the same. So, no need to drag the full set of archs when
+   linking a tool.
+   The VEX library is nicely split in arch independent and arch dependent
+   objects. Only main_main.c is dragging the various arch specific files.
+   So, main_main.c (the main entry point of the VEX library) is compiled
+   only for the current guest/host arch.
+
+   This file ensures we recompile main_main.c with all archs activated.
+   
+   So, a VEX user can decide (at link time) to use a 'single arch' VEX lib,
+   or to use a multiarch VEX lib.
+   If t1.o is a 'main' that calls LibVEX_Translate, then
+   to link with a single arch VEX lib, use e.g. the following :
+     gcc -o t1single t1.o -LInst/lib/valgrind  -lvex-amd64-linux -lgcc
+
+   to link with a multi arch VEX lib, you must insert 
+     -lvexmultiarch-amd64-linux *before* -lvex-amd64-linux
+   i.e;
+     gcc -o t1multi t1.o \
+        -LInst/lib/valgrind -lvexmultiarch-x86-linux -lvex-amd64-linux -lgcc
+
+   t1single will only be able to translate from amd64 to amd64.
+   t1multi will be able to translate from any arch supported by VEX
+   to any other arch supported by VEX.
+   Note however that multiarch support is experimental and poorly
+   or not tested.
+*/
+
 #define VEXMULTIARCH 1
 #include "main_main.c"