include/pub_tool_libcsetjmp.h

   1
   2 /*--------------------------------------------------------------------*/
   3 /*--- A minimal setjmp/longjmp facility.     pub_tool_libcsetjmp.h ---*/
   4 /*--------------------------------------------------------------------*/
   5
   6 /*
   7    This file is part of Valgrind, a dynamic binary instrumentation
   8    framework.
   9
  10    Copyright (C) 2010-2012 Mozilla Inc
  11
  12    This program is free software; you can redistribute it and/or
  13    modify it under the terms of the GNU General Public License as
  14    published by the Free Software Foundation; either version 2 of the
  15    License, or (at your option) any later version.
  16
  17    This program is distributed in the hope that it will be useful, but
  18    WITHOUT ANY WARRANTY; without even the implied warranty of
  19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20    General Public License for more details.
  21
  22    You should have received a copy of the GNU General Public License
  23    along with this program; if not, write to the Free Software
  24    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  25    02111-1307, USA.
  26
  27    The GNU General Public License is contained in the file COPYING.
  28 */
  29
  30 /* Contributed by Julian Seward <jseward@acm.org> */
  31
  32 #ifndef __PUB_TOOL_LIBCSETJMP_H
  33 #define __PUB_TOOL_LIBCSETJMP_H
  34
  35 //--------------------------------------------------------------------
  36 // PURPOSE: Provides a minimal setjmp/longjmp facility, that saves/
  37 // restores integer registers, but not necessarily anything more.
  38 //--------------------------------------------------------------------
  39
  40
  41 /* This provides an extremely minimal setjmp/longjmp facility, in
  42    which only the host's integer registers are saved/restored.  Or at
  43    least, that is the minimal guaranteed functionality.
  44
  45    Until Apr 2011 we used __builtin_setjmp and __builtin_longjmp, but
  46    it appears that that is not always correctly implemented.  See
  47    https://bugs.kde.org/show_bug.cgi?id=259977.  So this module wraps
  48    those functions up and facilitates replacing them with our own
  49    implementations where necessary.
  50 */
  51
  52 /* --- !!! --- EXTERNAL HEADERS start --- !!! --- */
  53 #include <setjmp.h>
  54 /* --- !!! --- EXTERNAL HEADERS end --- !!! --- */
  55
  56
  57 /* Don't use jmp_buf, __builtin_setjmp or __builtin_longjmp directly.
  58    They don't always work reliably.  Instead use these macros, which
  59    provide the opportunity to supply alternative implementations as
  60    necessary.
  61
  62    Note that the abstraction is done with macros (ick) rather than
  63    functions and typedefs, since wrapping __builtin_setjmp up in a
  64    second function (eg, VG_(minimal_setjmp)) doesn't seem to work for
  65    whatever reason -- returns via a VG_(minimal_longjmp) go wrong.
  66
  67    VG_MINIMAL_SETJMP stores the current integer register state in the
  68    supplied argument, and returns zero.  VG_MINIMAL_LONGJMP resumes
  69    with the previously saved state, and returns a nonzero, word-sized
  70    value.  The caller must test all bits of the value in order to make
  71    a zero/non-zero determination.
  72 */
  73
  74 #if defined(VGP_ppc32_linux)
  75
  76 #define VG_MINIMAL_JMP_BUF(_name)        UInt _name [32+1+1]
  77 __attribute__((returns_twice))
  78 UWord VG_MINIMAL_SETJMP(VG_MINIMAL_JMP_BUF(_env));
  79 __attribute__((noreturn))
  80 void  VG_MINIMAL_LONGJMP(VG_MINIMAL_JMP_BUF(_env));
  81
  82
  83 #elif defined(VGP_ppc64_linux)
  84
  85 #define VG_MINIMAL_JMP_BUF(_name)        ULong _name [32+1+1]
  86 __attribute__((returns_twice))
  87 UWord VG_MINIMAL_SETJMP(VG_MINIMAL_JMP_BUF(_env));
  88 __attribute__((noreturn))
  89 void  VG_MINIMAL_LONGJMP(VG_MINIMAL_JMP_BUF(_env));
  90
  91
  92 #elif defined(VGP_amd64_linux) || defined(VGP_amd64_darwin)
  93
  94 #define VG_MINIMAL_JMP_BUF(_name)        ULong _name [16+1]
  95 __attribute__((returns_twice))
  96 UWord VG_MINIMAL_SETJMP(VG_MINIMAL_JMP_BUF(_env));
  97 __attribute__((noreturn))
  98 void  VG_MINIMAL_LONGJMP(VG_MINIMAL_JMP_BUF(_env));
  99
 100
 101 #elif defined(VGP_x86_linux) || defined(VGP_x86_darwin)
 102
 103 #define VG_MINIMAL_JMP_BUF(_name)        UInt _name [8+1]
 104 __attribute__((returns_twice))
 105 __attribute__((regparm(1))) // this is critical; don't delete
 106 UWord VG_MINIMAL_SETJMP(VG_MINIMAL_JMP_BUF(_env));
 107 __attribute__((noreturn))
 108 __attribute__((regparm(1))) // ditto
 109 void  VG_MINIMAL_LONGJMP(VG_MINIMAL_JMP_BUF(_env));
 110
 111 #elif defined(VGP_mips32_linux)
 112
 113 #define VG_MINIMAL_JMP_BUF(_name)        UInt _name [8+1+1+1+1]
 114 __attribute__((returns_twice))
 115 UWord VG_MINIMAL_SETJMP(VG_MINIMAL_JMP_BUF(_env));
 116 __attribute__((noreturn))
 117 void  VG_MINIMAL_LONGJMP(VG_MINIMAL_JMP_BUF(_env));
 118
 119 #else
 120
 121 /* The default implementation. */
 122 #define VG_MINIMAL_JMP_BUF(_name) jmp_buf _name
 123 #define VG_MINIMAL_SETJMP(_env)   ((UWord)(__builtin_setjmp((_env))))
 124 #define VG_MINIMAL_LONGJMP(_env)  __builtin_longjmp((_env),1)
 125
 126 #endif
 127
 128 #endif   // __PUB_TOOL_LIBCSETJMP_H
 129
 130 /*--------------------------------------------------------------------*/
 131 /*--- end                                    pub_tool_libcsetjmp.h ---*/
 132 /*--------------------------------------------------------------------*/