include/pub_tool_basics.h

/*--------------------------------------------------------------------*/
/*--- Header included by every tool C file.      pub_tool_basics.h ---*/
/*--------------------------------------------------------------------*/

/*
   This file is part of Valgrind, a dynamic binary instrumentation
   framework.

   Copyright (C) 2000-2009 Julian Seward 
      jseward@acm.org

   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., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file COPYING.
*/

#ifndef __PUB_TOOL_BASICS_H
#define __PUB_TOOL_BASICS_H

//--------------------------------------------------------------------
// PURPOSE: This header should be imported by every single C file in
// tools.  It contains the basic types and other things needed everywhere.
// There is no corresponding C file because this isn't a module
// containing executable code, it's all just declarations.
//--------------------------------------------------------------------

/* ---------------------------------------------------------------------
   Other headers to include
   ------------------------------------------------------------------ */

// VEX defines Char, UChar, Short, UShort, Int, UInt, Long, ULong,
// Addr32, Addr64, HWord, HChar, Bool, False and True.
#include "libvex_basictypes.h"

// For varargs types
#include <stdarg.h>

/* For HAVE_BUILTIN_EXPECT */
#include "config.h"


/* ---------------------------------------------------------------------
   symbol prefixing
   ------------------------------------------------------------------ */
 
// All symbols externally visible from Valgrind are prefixed
// as specified here to avoid namespace conflict problems.
//
// VG_ is for symbols exported from modules.  ML_ (module-local) is
// for symbols which are not intended to be visible outside modules,
// but which cannot be declared as C 'static's since they need to be
// visible across C files within a given module.  It is a mistake for
// a ML_ name to appear in a pub_core_*.h or pub_tool_*.h file.
// Likewise it is a mistake for a VG_ name to appear in a priv_*.h
// file. 

#define VGAPPEND(str1,str2) str1##str2

#define VG_(str)    VGAPPEND(vgPlain_,          str)
#define ML_(str)    VGAPPEND(vgModuleLocal_,    str)


/* ---------------------------------------------------------------------
   builtin types
   ------------------------------------------------------------------ */

// By choosing the right types, we can get these right for 32-bit and 64-bit
// platforms without having to do any conditional compilation or anything.
// POSIX references:
// - http://www.opengroup.org/onlinepubs/009695399/basedefs/sys/types.h.html
// - http://www.opengroup.org/onlinepubs/009695399/basedefs/stddef.h.html
// 
// Size in bits on:                          32-bit archs   64-bit archs
//                                           ------------   ------------
typedef unsigned long          UWord;     // 32             64
typedef   signed long           Word;     // 32             64

// Addr is for holding an address.  AddrH was intended to be "Addr on the
// host", for the notional case where host word size != guest word size.
// But since the assumption that host arch == guest arch has become so
// deeply wired in, it's a pretty pointless distinction now.
typedef UWord                  Addr;      // 32             64
typedef UWord                  AddrH;     // 32             64

// Our equivalents of POSIX 'size_t' and 'ssize_t':
// - size_t is an "unsigned integer type of the result of the sizeof operator".
// - ssize_t is "used for a count of bytes or an error indication".
typedef UWord                  SizeT;     // 32             64
typedef  Word                 SSizeT;     // 32             64

// Our equivalent of POSIX 'ptrdiff_t':
// - ptrdiff_t is a "signed integer type of the result of subtracting two
//   pointers".
// We use it for memory offsets, eg. the offset into a memory block.
typedef  Word                 PtrdiffT;   // 32             64

// Our equivalent of POSIX 'off_t':
// - off_t is "used for file sizes".
// At one point we were using it for memory offsets, but PtrdiffT should be
// used in those cases.
typedef Word                   OffT;      // 32             64
typedef Long                 Off64T;      // 64             64

#if !defined(NULL)
#  define NULL ((void*)0)
#endif

/* This is just too useful to not have around the place somewhere. */
typedef  struct { UWord uw1; UWord uw2; }  UWordPair;


/* ---------------------------------------------------------------------
   non-builtin types
   ------------------------------------------------------------------ */

// These probably shouldn't be here, but moving them to their logical
// modules results in a lot more #includes...

/* ThreadIds are simply indices into the VG_(threads)[] array. */
typedef UInt ThreadId;

/* An abstraction of syscall return values.
   Linux:
      When _isError == False, 
         _val holds the return value.
      When _isError == True,  
         _err holds the error code.

   AIX:
      _res is the POSIX result of the syscall.
      _err is the corresponding errno value.
      _isError === _err==0

      Unlike on Linux, it is possible for _err to be nonzero (thus an
      error has occurred), nevertheless _res is also nonzero.  AIX
      userspace does not appear to consistently inspect _err to
      determine whether or not an error has occurred.  For example,
      sys_open() will return -1 for _val if a file cannot be opened,
      as well as the relevant errno value in _err, but AIX userspace
      then consults _val to figure out if the syscall failed, rather
      than looking at _err.  Hence we need to represent them both.

   Darwin:
      Interpretation depends on _mode:
      MACH, MDEP:
         these can never 'fail' (apparently).  The result of the
         syscall is a single host word, _wLO.
      UNIX:
         Can record a double-word error or a double-word result:
         When _mode is SysRes_UNIX_OK,  _wHI:_wLO holds the result.
         When _mode is SysRes_UNIX_ERR, _wHI:_wLO holds the error code.
         Probably the high word of an error is always ignored by
         userspace, but we have to record it, so that we can correctly
         update both EDX and EAX (in guest state) given a SysRes, if
         we're required to.
*/
#if defined(VGO_linux)
typedef
   struct {
      UWord _val;
      Bool  _isError;
   }
   SysRes;
#elif defined(VGO_aix5)
typedef
   struct {
      UWord _res;
      UWord _err;
      Bool  _isError;
   }
   SysRes;
#else
#  error "Unknown OS"
#endif


/* ---- And now some basic accessor functions for it. ---- */

#if defined(VGO_linux)

static inline Bool sr_isError ( SysRes sr ) {
   return sr._isError;
}
static inline UWord sr_Res ( SysRes sr ) {
   return sr._isError ? 0 : sr._val;
}
static inline UWord sr_ResHI ( SysRes sr ) {
   return 0;
}
static inline UWord sr_Err ( SysRes sr ) {
   return sr._isError ? sr._val : 0;
}
static inline Bool sr_EQ ( SysRes sr1, SysRes sr2 ) {
   return sr1._val == sr2._val 
          && ((sr1._isError && sr2._isError) 
              || (!sr1._isError && !sr2._isError));
}

#elif defined(VGO_aix5)
#  error "need to define SysRes accessors on AIX5 (copy from 3.4.1 sources)"


#else
#  error "Unknown OS"
#endif


/* ---------------------------------------------------------------------
   Miscellaneous (word size, endianness, regparmness, stringification)
   ------------------------------------------------------------------ */

/* Word size: this is going to be either 4 or 8. */
// It should probably be in m_machine.
#define VG_WORDSIZE VEX_HOST_WORDSIZE

/* Endianness */
#undef VG_BIGENDIAN
#undef VG_LITTLEENDIAN

#if defined(VGA_x86) || defined(VGA_amd64)
#  define VG_LITTLEENDIAN 1
#elif defined(VGA_ppc32) || defined(VGA_ppc64)
#  define VG_BIGENDIAN 1
#endif

/* Regparmness */
#if defined(VGA_x86)
#  define VG_REGPARM(n)            __attribute__((regparm(n)))
#elif defined(VGA_amd64) || defined(VGA_ppc32) || defined(VGA_ppc64)
#  define VG_REGPARM(n)            /* */
#else
#  error Unknown arch
#endif

/* Macro games */
#define VG_STRINGIFZ(__str)  #__str
#define VG_STRINGIFY(__str)  VG_STRINGIFZ(__str)

// Where to send bug reports to.
#define VG_BUGS_TO "www.valgrind.org"

/* Branch prediction hints. */
#if HAVE_BUILTIN_EXPECT
#  define LIKELY(x)   __builtin_expect(!!(x), 1)
#  define UNLIKELY(x) __builtin_expect((x), 0)
#else
#  define LIKELY(x)   (x)
#  define UNLIKELY(x) (x)
#endif


#endif /* __PUB_TOOL_BASICS_H */

/*--------------------------------------------------------------------*/
/*--- end                                                          ---*/
/*--------------------------------------------------------------------*/