vg_main.c

/*--------------------------------------------------------------------*/
/*--- C startup stuff, reached from vg_startup.S.                  ---*/
/*---                                                    vg_main.c ---*/
/*--------------------------------------------------------------------*/

/*
   This file is part of Valgrind, an x86 protected-mode emulator 
   designed for debugging and profiling binaries on x86-Unixes.

   Copyright (C) 2000-2002 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 LICENSE.
*/

#include "vg_include.h"
#include "vg_constants.h"


/* ---------------------------------------------------------------------
   Compute offsets into baseBlock.  See comments in vg_include.h.
   ------------------------------------------------------------------ */

/* The variables storing offsets. */

#define INVALID_OFFSET (-1)

Int VGOFF_(m_eax) = INVALID_OFFSET;
Int VGOFF_(m_ecx) = INVALID_OFFSET;
Int VGOFF_(m_edx) = INVALID_OFFSET;
Int VGOFF_(m_ebx) = INVALID_OFFSET;
Int VGOFF_(m_esp) = INVALID_OFFSET;
Int VGOFF_(m_ebp) = INVALID_OFFSET;
Int VGOFF_(m_esi) = INVALID_OFFSET;
Int VGOFF_(m_edi) = INVALID_OFFSET;
Int VGOFF_(m_eflags) = INVALID_OFFSET;
Int VGOFF_(m_fpustate) = INVALID_OFFSET;
Int VGOFF_(m_eip) = INVALID_OFFSET;
Int VGOFF_(spillslots) = INVALID_OFFSET;
Int VGOFF_(sh_eax) = INVALID_OFFSET;
Int VGOFF_(sh_ecx) = INVALID_OFFSET;
Int VGOFF_(sh_edx) = INVALID_OFFSET;
Int VGOFF_(sh_ebx) = INVALID_OFFSET;
Int VGOFF_(sh_esp) = INVALID_OFFSET;
Int VGOFF_(sh_ebp) = INVALID_OFFSET;
Int VGOFF_(sh_esi) = INVALID_OFFSET;
Int VGOFF_(sh_edi) = INVALID_OFFSET;
Int VGOFF_(sh_eflags) = INVALID_OFFSET;
Int VGOFF_(helper_idiv_64_32) = INVALID_OFFSET;
Int VGOFF_(helper_div_64_32) = INVALID_OFFSET;
Int VGOFF_(helper_idiv_32_16) = INVALID_OFFSET;
Int VGOFF_(helper_div_32_16) = INVALID_OFFSET;
Int VGOFF_(helper_idiv_16_8) = INVALID_OFFSET;
Int VGOFF_(helper_div_16_8) = INVALID_OFFSET;
Int VGOFF_(helper_imul_32_64) = INVALID_OFFSET;
Int VGOFF_(helper_mul_32_64) = INVALID_OFFSET;
Int VGOFF_(helper_imul_16_32) = INVALID_OFFSET;
Int VGOFF_(helper_mul_16_32) = INVALID_OFFSET;
Int VGOFF_(helper_imul_8_16) = INVALID_OFFSET;
Int VGOFF_(helper_mul_8_16) = INVALID_OFFSET;
Int VGOFF_(helper_CLD) = INVALID_OFFSET;
Int VGOFF_(helper_STD) = INVALID_OFFSET;
Int VGOFF_(helper_get_dirflag) = INVALID_OFFSET;
Int VGOFF_(helper_CLC) = INVALID_OFFSET;
Int VGOFF_(helper_STC) = INVALID_OFFSET;
Int VGOFF_(helper_shldl) = INVALID_OFFSET;
Int VGOFF_(helper_shldw) = INVALID_OFFSET;
Int VGOFF_(helper_shrdl) = INVALID_OFFSET;
Int VGOFF_(helper_shrdw) = INVALID_OFFSET;
Int VGOFF_(helper_RDTSC) = INVALID_OFFSET;
Int VGOFF_(helper_CPUID) = INVALID_OFFSET;
Int VGOFF_(helper_BSWAP) = INVALID_OFFSET;
Int VGOFF_(helper_bsf) = INVALID_OFFSET;
Int VGOFF_(helper_bsr) = INVALID_OFFSET;
Int VGOFF_(helper_fstsw_AX) = INVALID_OFFSET;
Int VGOFF_(helper_SAHF) = INVALID_OFFSET;
Int VGOFF_(helper_DAS) = INVALID_OFFSET;
Int VGOFF_(helper_DAA) = INVALID_OFFSET;
Int VGOFF_(helper_value_check4_fail) = INVALID_OFFSET;
Int VGOFF_(helper_value_check2_fail) = INVALID_OFFSET;
Int VGOFF_(helper_value_check1_fail) = INVALID_OFFSET;
Int VGOFF_(helper_value_check0_fail) = INVALID_OFFSET;
Int VGOFF_(helperc_LOADV4) = INVALID_OFFSET;
Int VGOFF_(helperc_LOADV2) = INVALID_OFFSET;
Int VGOFF_(helperc_LOADV1) = INVALID_OFFSET;
Int VGOFF_(helperc_STOREV4) = INVALID_OFFSET;
Int VGOFF_(helperc_STOREV2) = INVALID_OFFSET;
Int VGOFF_(helperc_STOREV1) = INVALID_OFFSET;
Int VGOFF_(handle_esp_assignment) = INVALID_OFFSET;
Int VGOFF_(fpu_write_check) = INVALID_OFFSET;
Int VGOFF_(fpu_read_check) = INVALID_OFFSET;
Int VGOFF_(cachesim_log_non_mem_instr) = INVALID_OFFSET;
Int VGOFF_(cachesim_log_mem_instr)     = INVALID_OFFSET;

/* This is the actual defn of baseblock. */
UInt VG_(baseBlock)[VG_BASEBLOCK_WORDS];

/* Words. */
static Int baB_off = 0;

/* Returns the offset, in words. */
static Int alloc_BaB ( Int words )
{
   Int off = baB_off;
   baB_off += words;
   if (baB_off >= VG_BASEBLOCK_WORDS)
      VG_(panic)( "alloc_BaB: baseBlock is too small");

   return off;   
}

/* Allocate 1 word in baseBlock and set it to the given value. */
static Int alloc_BaB_1_set ( Addr a )
{
   Int off = alloc_BaB(1);
   VG_(baseBlock)[off] = (UInt)a;
   return off;
}


/* Here we assign actual offsets.  It's important to get the most
   popular referents within 128 bytes of the start, so we can take
   advantage of short addressing modes relative to %ebp.  Popularity
   of offsets was measured on 22 Feb 02 running a KDE application, and
   the slots rearranged accordingly, with a 1.5% reduction in total
   size of translations. */

static void vg_init_baseBlock ( void )
{
   baB_off = 0;

   /* Those with offsets under 128 are carefully chosen. */

   /* WORD offsets in this column */
   /* 0   */ VGOFF_(m_eax)     = alloc_BaB(1);
   /* 1   */ VGOFF_(m_ecx)     = alloc_BaB(1);
   /* 2   */ VGOFF_(m_edx)     = alloc_BaB(1);
   /* 3   */ VGOFF_(m_ebx)     = alloc_BaB(1);
   /* 4   */ VGOFF_(m_esp)     = alloc_BaB(1);
   /* 5   */ VGOFF_(m_ebp)     = alloc_BaB(1);
   /* 6   */ VGOFF_(m_esi)     = alloc_BaB(1);
   /* 7   */ VGOFF_(m_edi)     = alloc_BaB(1);
   /* 8   */ VGOFF_(m_eflags)  = alloc_BaB(1);

   /* 9   */ VGOFF_(sh_eax)    = alloc_BaB(1);
   /* 10  */ VGOFF_(sh_ecx)    = alloc_BaB(1);
   /* 11  */ VGOFF_(sh_edx)    = alloc_BaB(1);
   /* 12  */ VGOFF_(sh_ebx)    = alloc_BaB(1);
   /* 13  */ VGOFF_(sh_esp)    = alloc_BaB(1);
   /* 14  */ VGOFF_(sh_ebp)    = alloc_BaB(1);
   /* 15  */ VGOFF_(sh_esi)    = alloc_BaB(1);
   /* 16  */ VGOFF_(sh_edi)    = alloc_BaB(1);
   /* 17  */ VGOFF_(sh_eflags) = alloc_BaB(1);

   /* 17a */ 
   VGOFF_(cachesim_log_non_mem_instr)  
      = alloc_BaB_1_set( (Addr) & VG_(cachesim_log_non_mem_instr) );
   /* 17b */ 
   VGOFF_(cachesim_log_mem_instr)  
      = alloc_BaB_1_set( (Addr) & VG_(cachesim_log_mem_instr) );

   /* 18  */ 
   VGOFF_(helper_value_check4_fail) 
      = alloc_BaB_1_set( (Addr) & VG_(helper_value_check4_fail) );
   /* 19 */
   VGOFF_(helper_value_check0_fail)
      = alloc_BaB_1_set( (Addr) & VG_(helper_value_check0_fail) );

   /* 20  */
   VGOFF_(helperc_STOREV4)
      = alloc_BaB_1_set( (Addr) & VG_(helperc_STOREV4) );
   /* 21  */
   VGOFF_(helperc_STOREV1)
      = alloc_BaB_1_set( (Addr) & VG_(helperc_STOREV1) );

   /* 22  */
   VGOFF_(helperc_LOADV4)
      = alloc_BaB_1_set( (Addr) & VG_(helperc_LOADV4) );
   /* 23  */
   VGOFF_(helperc_LOADV1)
      = alloc_BaB_1_set( (Addr) & VG_(helperc_LOADV1) );

   /* 24  */
   VGOFF_(handle_esp_assignment)
      = alloc_BaB_1_set( (Addr) & VGM_(handle_esp_assignment) );

   /* 25 */
   VGOFF_(m_eip) = alloc_BaB(1);

   /* There are currently 24 spill slots */
   /* 26 .. 49  This overlaps the magic boundary at >= 32 words, but
      most spills are to low numbered spill slots, so the ones above
      the boundary don't see much action. */
   VGOFF_(spillslots) = alloc_BaB(VG_MAX_SPILLSLOTS);

   /* These two pushed beyond the boundary because 2-byte transactions
      are rare. */
   /* 50  */
   VGOFF_(helperc_STOREV2)
      = alloc_BaB_1_set( (Addr) & VG_(helperc_STOREV2) );
   /* 51  */
   VGOFF_(helperc_LOADV2)
      = alloc_BaB_1_set( (Addr) & VG_(helperc_LOADV2) );

   /* 52  */
   VGOFF_(fpu_write_check)
      = alloc_BaB_1_set( (Addr) & VGM_(fpu_write_check) );
   /* 53  */
   VGOFF_(fpu_read_check)
      = alloc_BaB_1_set( (Addr) & VGM_(fpu_read_check) );

   /* Actually I don't think these two are ever used. */
   /* 54  */ 
   VGOFF_(helper_value_check2_fail)
      = alloc_BaB_1_set( (Addr) & VG_(helper_value_check2_fail) );
   /* 55  */ 
   VGOFF_(helper_value_check1_fail)
      = alloc_BaB_1_set( (Addr) & VG_(helper_value_check1_fail) );

   /* I gave up counting at this point.  Since they're way above the
      short-amode-boundary, there's no point. */

   VGOFF_(m_fpustate) = alloc_BaB(VG_SIZE_OF_FPUSTATE_W);

   VGOFF_(helper_idiv_64_32)
      = alloc_BaB_1_set( (Addr) & VG_(helper_idiv_64_32) );
   VGOFF_(helper_div_64_32)
      = alloc_BaB_1_set( (Addr) & VG_(helper_div_64_32) );
   VGOFF_(helper_idiv_32_16)
      = alloc_BaB_1_set( (Addr) & VG_(helper_idiv_32_16) );
   VGOFF_(helper_div_32_16)
      = alloc_BaB_1_set( (Addr) & VG_(helper_div_32_16) );
   VGOFF_(helper_idiv_16_8)
      = alloc_BaB_1_set( (Addr) & VG_(helper_idiv_16_8) );
   VGOFF_(helper_div_16_8)
      = alloc_BaB_1_set( (Addr) & VG_(helper_div_16_8) );

   VGOFF_(helper_imul_32_64)
      = alloc_BaB_1_set( (Addr) & VG_(helper_imul_32_64) );
   VGOFF_(helper_mul_32_64)
      = alloc_BaB_1_set( (Addr) & VG_(helper_mul_32_64) );
   VGOFF_(helper_imul_16_32)
      = alloc_BaB_1_set( (Addr) & VG_(helper_imul_16_32) );
   VGOFF_(helper_mul_16_32)
      = alloc_BaB_1_set( (Addr) & VG_(helper_mul_16_32) );
   VGOFF_(helper_imul_8_16)
      = alloc_BaB_1_set( (Addr) & VG_(helper_imul_8_16) );
   VGOFF_(helper_mul_8_16)
      = alloc_BaB_1_set( (Addr) & VG_(helper_mul_8_16) );

   VGOFF_(helper_CLD)
      = alloc_BaB_1_set( (Addr) & VG_(helper_CLD) );
   VGOFF_(helper_STD)
      = alloc_BaB_1_set( (Addr) & VG_(helper_STD) );
   VGOFF_(helper_get_dirflag)
      = alloc_BaB_1_set( (Addr) & VG_(helper_get_dirflag) );

   VGOFF_(helper_CLC)
      = alloc_BaB_1_set( (Addr) & VG_(helper_CLC) );
    VGOFF_(helper_STC)
      = alloc_BaB_1_set( (Addr) & VG_(helper_STC) );

   VGOFF_(helper_shldl)
      = alloc_BaB_1_set( (Addr) & VG_(helper_shldl) );
   VGOFF_(helper_shldw)
      = alloc_BaB_1_set( (Addr) & VG_(helper_shldw) );
   VGOFF_(helper_shrdl)
      = alloc_BaB_1_set( (Addr) & VG_(helper_shrdl) );
   VGOFF_(helper_shrdw)
      = alloc_BaB_1_set( (Addr) & VG_(helper_shrdw) );

   VGOFF_(helper_RDTSC)
      = alloc_BaB_1_set( (Addr) & VG_(helper_RDTSC) );
   VGOFF_(helper_CPUID)
      = alloc_BaB_1_set( (Addr) & VG_(helper_CPUID) );

   VGOFF_(helper_bsf)
      = alloc_BaB_1_set( (Addr) & VG_(helper_bsf) );
   VGOFF_(helper_bsr)
      = alloc_BaB_1_set( (Addr) & VG_(helper_bsr) );

   VGOFF_(helper_fstsw_AX)
      = alloc_BaB_1_set( (Addr) & VG_(helper_fstsw_AX) );
   VGOFF_(helper_SAHF)
      = alloc_BaB_1_set( (Addr) & VG_(helper_SAHF) );
   VGOFF_(helper_DAS)
      = alloc_BaB_1_set( (Addr) & VG_(helper_DAS) );
   VGOFF_(helper_DAA)
      = alloc_BaB_1_set( (Addr) & VG_(helper_DAA) );
}


/* ---------------------------------------------------------------------
   Global entities which are not referenced from generated code.
   ------------------------------------------------------------------ */

/* The stack on which Valgrind runs.  We can't use the same stack as
   the simulatee -- that's an important design decision.  */
UInt VG_(stack)[10000];

/* Ditto our signal delivery stack. */
UInt VG_(sigstack)[10000];

/* Saving stuff across system calls. */
UInt VG_(real_fpu_state_saved_over_syscall)[VG_SIZE_OF_FPUSTATE_W];
Addr VG_(esp_saved_over_syscall);

/* Counts downwards in vg_run_innerloop. */
UInt VG_(dispatch_ctr);


/* 64-bit counter for the number of basic blocks done. */
ULong VG_(bbs_done);
/* 64-bit counter for the number of bbs to go before a debug exit. */
ULong VG_(bbs_to_go);

/* Produce debugging output? */
Bool VG_(disassemble) = False;

/* The current LRU epoch. */
UInt VG_(current_epoch) = 0;

/* This is the ThreadId of the last thread the scheduler ran. */
ThreadId VG_(last_run_tid) = 0;


/* ---------------------------------------------------------------------
   Counters, for informational purposes only.
   ------------------------------------------------------------------ */

/* Number of lookups which miss the fast tt helper. */
UInt VG_(tt_fast_misses) = 0;


/* Counts for LRU informational messages. */

/* Number and total o/t size of new translations this epoch. */
UInt VG_(this_epoch_in_count) = 0;
UInt VG_(this_epoch_in_osize) = 0;
UInt VG_(this_epoch_in_tsize) = 0;
/* Number and total o/t size of discarded translations this epoch. */
UInt VG_(this_epoch_out_count) = 0;
UInt VG_(this_epoch_out_osize) = 0;
UInt VG_(this_epoch_out_tsize) = 0;
/* Number and total o/t size of translations overall. */
UInt VG_(overall_in_count) = 0;
UInt VG_(overall_in_osize) = 0;
UInt VG_(overall_in_tsize) = 0;
/* Number and total o/t size of discards overall. */
UInt VG_(overall_out_count) = 0;
UInt VG_(overall_out_osize) = 0;
UInt VG_(overall_out_tsize) = 0;

/* The number of LRU-clearings of TT/TC. */
UInt VG_(number_of_lrus) = 0;


/* Counts pertaining to the register allocator. */

/* total number of uinstrs input to reg-alloc */
UInt VG_(uinstrs_prealloc) = 0;

/* total number of uinstrs added due to spill code */
UInt VG_(uinstrs_spill) = 0;

/* number of bbs requiring spill code */
UInt VG_(translations_needing_spill) = 0;

/* total of register ranks over all translations */
UInt VG_(total_reg_rank) = 0;


/* Counts pertaining to internal sanity checking. */
UInt VG_(sanity_fast_count) = 0;
UInt VG_(sanity_slow_count) = 0;

/* Counts pertaining to the scheduler. */
UInt VG_(num_scheduling_events_MINOR) = 0;
UInt VG_(num_scheduling_events_MAJOR) = 0;


/* ---------------------------------------------------------------------
   Values derived from command-line options.
   ------------------------------------------------------------------ */

Bool   VG_(clo_check_addrVs);
Bool   VG_(clo_GDB_attach);
Int    VG_(sanity_level);
Int    VG_(clo_verbosity);
Bool   VG_(clo_demangle);
Bool   VG_(clo_leak_check);
Bool   VG_(clo_show_reachable);
Int    VG_(clo_leak_resolution);
Bool   VG_(clo_sloppy_malloc);
Bool   VG_(clo_partial_loads_ok);
Bool   VG_(clo_trace_children);
Int    VG_(clo_logfile_fd);
Int    VG_(clo_freelist_vol);
Bool   VG_(clo_workaround_gcc296_bugs);
Int    VG_(clo_n_suppressions);
Char*  VG_(clo_suppressions)[VG_CLO_MAX_SFILES];
Bool   VG_(clo_single_step);
Bool   VG_(clo_optimise);
Bool   VG_(clo_instrument);
Bool   VG_(clo_cleanup);
Bool   VG_(clo_cachesim);
Int    VG_(clo_smc_check);
Bool   VG_(clo_trace_syscalls);
Bool   VG_(clo_trace_signals);
Bool   VG_(clo_trace_symtab);
Bool   VG_(clo_trace_malloc);
Bool   VG_(clo_trace_sched);
Int    VG_(clo_trace_pthread_level);
ULong  VG_(clo_stop_after);
Int    VG_(clo_dump_error);
Int    VG_(clo_backtrace_size);
Char*  VG_(clo_weird_hacks);

/* This Bool is needed by wrappers in vg_clientmalloc.c to decide how
   to behave.  Initially we say False. */
Bool VG_(running_on_simd_CPU) = False;

/* Holds client's %esp at the point we gained control. */
Addr VG_(esp_at_startup);

/* As deduced from VG_(esp_at_startup), the client's argc, argv[] and
   envp[] as extracted from the client's stack at startup-time. */
Int    VG_(client_argc);
Char** VG_(client_argv);
Char** VG_(client_envp);

/* A place into which to copy the value of env var VG_ARGS, so we
   don't have to modify the original. */
static Char vg_cmdline_copy[M_VG_CMDLINE_STRLEN];


/* ---------------------------------------------------------------------
   Processing of command-line options.
   ------------------------------------------------------------------ */

static void bad_option ( Char* opt )
{
   VG_(shutdown_logging)();
   VG_(clo_logfile_fd) = 2; /* stderr */
   VG_(printf)("valgrind.so: Bad option `%s'; aborting.\n", opt);
   VG_(exit)(1);
}

static void config_error ( Char* msg )
{
   VG_(shutdown_logging)();
   VG_(clo_logfile_fd) = 2; /* stderr */
   VG_(printf)("valgrind.so: Startup or configuration error:\n\t%s\n", msg);
   VG_(printf)("valgrind.so: Unable to start up properly.  Giving up.\n");
   VG_(exit)(1);
}

static void args_grok_error ( Char* msg )
{
   VG_(shutdown_logging)();
   VG_(clo_logfile_fd) = 2; /* stderr */
   VG_(printf)("valgrind.so: When searching for "
               "client's argc/argc/envp:\n\t%s\n", msg);
   config_error("couldn't find client's argc/argc/envp");
}   


static void process_cmd_line_options ( void )
{
   UChar* argv[M_VG_CMDLINE_OPTS];
   UInt   argc;
   UChar* p;
   UChar* str;
   Int    i, eventually_logfile_fd, ctr;

#  define ISSPACE(cc)      ((cc) == ' ' || (cc) == '\t' || (cc) == '\n')
#  define STREQ(s1,s2)     (0==VG_(strcmp_ws)((s1),(s2)))
#  define STREQN(nn,s1,s2) (0==VG_(strncmp_ws)((s1),(s2),(nn)))

   /* Set defaults. */
   VG_(clo_check_addrVs)     = True;
   VG_(clo_GDB_attach)       = False;
   VG_(sanity_level)         = 1;
   VG_(clo_verbosity)        = 1;
   VG_(clo_demangle)         = True;
   VG_(clo_leak_check)       = False;
   VG_(clo_show_reachable)   = False;
   VG_(clo_leak_resolution)  = 2;
   VG_(clo_sloppy_malloc)    = False;
   VG_(clo_partial_loads_ok) = True;
   VG_(clo_trace_children)   = False;
   VG_(clo_logfile_fd)       = 2; /* stderr */
   VG_(clo_freelist_vol)     = 1000000;
   VG_(clo_workaround_gcc296_bugs) = False;
   VG_(clo_n_suppressions)   = 0;
   VG_(clo_single_step)      = False;
   VG_(clo_optimise)         = True;
   VG_(clo_instrument)       = True;
   VG_(clo_cleanup)          = True;
   VG_(clo_smc_check)        = /* VG_CLO_SMC_SOME */ VG_CLO_SMC_NONE;
   VG_(clo_trace_syscalls)   = False;
   VG_(clo_trace_signals)    = False;
   VG_(clo_trace_symtab)     = False;
   VG_(clo_trace_malloc)     = False;
   VG_(clo_trace_sched)      = False;
   VG_(clo_trace_pthread_level) = 0;
   VG_(clo_stop_after)       = 1000000000000LL;
   VG_(clo_dump_error)       = 0;
   VG_(clo_backtrace_size)   = 4;
   VG_(clo_weird_hacks)      = NULL;

   eventually_logfile_fd = VG_(clo_logfile_fd);

   /* Once logging is started, we can safely send messages pertaining
      to failures in initialisation. */
   VG_(startup_logging)();


   /* (Suggested by Fabrice Bellard ... )
      We look for the Linux ELF table and go down until we find the
      envc & envp. It is not full proof, but these structures should
      change less often than the libc ones. */
   {
       UInt* sp = 0; /* bogus init to keep gcc -O happy */

       /* locate the top of the stack */
       if (VG_STACK_MATCHES_BASE( VG_(esp_at_startup), 
                                  VG_STARTUP_STACK_BASE_1 )) {
          sp = (UInt*)VG_STARTUP_STACK_BASE_1;
       } else
       if (VG_STACK_MATCHES_BASE( VG_(esp_at_startup), 
                                  VG_STARTUP_STACK_BASE_2 )) {
          sp = (UInt*)VG_STARTUP_STACK_BASE_2;
       } else {
          args_grok_error(
             "startup %esp is not near any VG_STARTUP_STACK_BASE_*\n   "
             "constants defined in vg_include.h.  You should investigate."
          );
       }
 
       /* we locate: NEW_AUX_ENT(1, AT_PAGESZ, ELF_EXEC_PAGESIZE) in
          the elf interpreter table */
       sp -= 2;
       while (sp[0] != VKI_AT_PAGESZ || sp[1] != 4096) {
           /* VG_(printf)("trying %p\n", sp); */
           sp--;
       }

       if (sp[2] == VKI_AT_BASE 
           && sp[0] == VKI_AT_PAGESZ
           && sp[-2] == VKI_AT_PHNUM
           && sp[-4] == VKI_AT_PHENT
           && sp[-6] == VKI_AT_PHDR
           && sp[-6-1] == 0) {
          if (0)
             VG_(printf)("Looks like you've got a 2.2.X kernel here.\n");
          sp -= 6;
       } else
       if (sp[2] == VKI_AT_CLKTCK
           && sp[0] == VKI_AT_PAGESZ
           && sp[-2] == VKI_AT_HWCAP
           && sp[-2-1] == 0) {
          if (0)
             VG_(printf)("Looks like you've got a 2.4.X kernel here.\n");
          sp -= 2;
       } else
       if (sp[2] == VKI_AT_CLKTCK
           && sp[0] == VKI_AT_PAGESZ
           && sp[-2] == VKI_AT_HWCAP
           && sp[-2-20-1] == 0) {
          if (0)
             VG_(printf)("Looks like you've got a early 2.4.X kernel here.\n");
          sp -= 22;
       } else
         args_grok_error(
            "ELF frame does not look like 2.2.X or 2.4.X.\n   "
            "See kernel sources linux/fs/binfmt_elf.c to make sense of this."
         );

       sp--;
       if (*sp != 0)
	 args_grok_error("can't find NULL at end of env[]");

       /* sp now points to NULL at the end of env[] */
       ctr = 0;
       while (True) {
           sp --;
           if (*sp == 0) break;
           if (++ctr >= 1000)
              args_grok_error(
                 "suspiciously many (1000) env[] entries; giving up");
           
       }
       /* sp now points to NULL at the end of argv[] */
       VG_(client_envp) = (Char**)(sp+1);

       ctr = 0;
       VG_(client_argc) = 0;
       while (True) {
          sp--;
          if (*sp == VG_(client_argc))
             break;
          VG_(client_argc)++;
           if (++ctr >= 1000)
              args_grok_error(
                 "suspiciously many (1000) argv[] entries; giving up");
       }

       VG_(client_argv) = (Char**)(sp+1);
   }

   /* Now that VG_(client_envp) has been set, we can extract the args
      for Valgrind itself.  Copy into global var so that we don't have to
      write zeroes to the getenv'd value itself. */
   str = VG_(getenv)("VG_ARGS");
   argc = 0;

   if (!str) {
      config_error("Can't read options from env var VG_ARGS.");
   }

   if (VG_(strlen)(str) >= M_VG_CMDLINE_STRLEN-1) {
      config_error("Command line length exceeds M_CMDLINE_STRLEN.");
   }
   VG_(strcpy)(vg_cmdline_copy, str);
   str = NULL;

   p = &vg_cmdline_copy[0];
   while (True) {
      while (ISSPACE(*p)) { *p = 0; p++; }
      if (*p == 0) break;
      if (argc < M_VG_CMDLINE_OPTS-1) { 
         argv[argc] = p; argc++; 
      } else {
         config_error(
            "Found more than M_CMDLINE_OPTS command-line opts.");
      }
      while (*p != 0 && !ISSPACE(*p)) p++;
   }

   for (i = 0; i < argc; i++) {

      if (STREQ(argv[i], "-v") || STREQ(argv[i], "--verbose"))
         VG_(clo_verbosity)++;
      else if (STREQ(argv[i], "-q") || STREQ(argv[i], "--quiet"))
         VG_(clo_verbosity)--;

      else if (STREQ(argv[i], "--check-addrVs=yes"))
         VG_(clo_check_addrVs) = True;
      else if (STREQ(argv[i], "--check-addrVs=no"))
         VG_(clo_check_addrVs) = False;

      else if (STREQ(argv[i], "--gdb-attach=yes"))
         VG_(clo_GDB_attach) = True;
      else if (STREQ(argv[i], "--gdb-attach=no"))
         VG_(clo_GDB_attach) = False;

      else if (STREQ(argv[i], "--demangle=yes"))
         VG_(clo_demangle) = True;
      else if (STREQ(argv[i], "--demangle=no"))
         VG_(clo_demangle) = False;

      else if (STREQ(argv[i], "--partial-loads-ok=yes"))
         VG_(clo_partial_loads_ok) = True;
      else if (STREQ(argv[i], "--partial-loads-ok=no"))
         VG_(clo_partial_loads_ok) = False;

      else if (STREQ(argv[i], "--leak-check=yes"))
         VG_(clo_leak_check) = True;
      else if (STREQ(argv[i], "--leak-check=no"))
         VG_(clo_leak_check) = False;

      else if (STREQ(argv[i], "--show-reachable=yes"))
         VG_(clo_show_reachable) = True;
      else if (STREQ(argv[i], "--show-reachable=no"))
         VG_(clo_show_reachable) = False;

      else if (STREQ(argv[i], "--leak-resolution=low"))
         VG_(clo_leak_resolution) = 2;
      else if (STREQ(argv[i], "--leak-resolution=med"))
         VG_(clo_leak_resolution) = 4;
      else if (STREQ(argv[i], "--leak-resolution=high"))
         VG_(clo_leak_resolution) = VG_DEEPEST_BACKTRACE;

      else if (STREQ(argv[i], "--sloppy-malloc=yes"))
         VG_(clo_sloppy_malloc) = True;
      else if (STREQ(argv[i], "--sloppy-malloc=no"))
         VG_(clo_sloppy_malloc) = False;

      else if (STREQ(argv[i], "--trace-children=yes"))
         VG_(clo_trace_children) = True;
      else if (STREQ(argv[i], "--trace-children=no"))
         VG_(clo_trace_children) = False;

      else if (STREQ(argv[i], "--workaround-gcc296-bugs=yes"))
         VG_(clo_workaround_gcc296_bugs) = True;
      else if (STREQ(argv[i], "--workaround-gcc296-bugs=no"))
         VG_(clo_workaround_gcc296_bugs) = False;

      else if (STREQN(15, argv[i], "--sanity-level="))
         VG_(sanity_level) = (Int)VG_(atoll)(&argv[i][15]);

      else if (STREQN(13, argv[i], "--logfile-fd="))
         eventually_logfile_fd = (Int)VG_(atoll)(&argv[i][13]);

      else if (STREQN(15, argv[i], "--freelist-vol=")) {
         VG_(clo_freelist_vol) = (Int)VG_(atoll)(&argv[i][15]);
         if (VG_(clo_freelist_vol) < 0) VG_(clo_freelist_vol) = 2;
      }

      else if (STREQN(15, argv[i], "--suppressions=")) {
         if (VG_(clo_n_suppressions) >= VG_CLO_MAX_SFILES) {
            VG_(message)(Vg_UserMsg, "Too many logfiles specified.");
            VG_(message)(Vg_UserMsg, 
                         "Increase VG_CLO_MAX_SFILES and recompile.");
            bad_option(argv[i]);
         }
         VG_(clo_suppressions)[VG_(clo_n_suppressions)] = &argv[i][15];
         VG_(clo_n_suppressions)++;
      }
      else if (STREQ(argv[i], "--single-step=yes"))
         VG_(clo_single_step) = True;
      else if (STREQ(argv[i], "--single-step=no"))
         VG_(clo_single_step) = False;

      else if (STREQ(argv[i], "--optimise=yes"))
         VG_(clo_optimise) = True;
      else if (STREQ(argv[i], "--optimise=no"))
         VG_(clo_optimise) = False;

      else if (STREQ(argv[i], "--instrument=yes"))
         VG_(clo_instrument) = True;
      else if (STREQ(argv[i], "--instrument=no"))
         VG_(clo_instrument) = False;

      else if (STREQ(argv[i], "--cleanup=yes"))
         VG_(clo_cleanup) = True;
      else if (STREQ(argv[i], "--cleanup=no"))
         VG_(clo_cleanup) = False;

      else if (STREQ(argv[i], "--cachesim=yes"))
         VG_(clo_cachesim) = True;     
      else if (STREQ(argv[i], "--cachesim=no"))
         VG_(clo_cachesim) = False;

      else if (STREQ(argv[i], "--smc-check=none"))
         VG_(clo_smc_check) = VG_CLO_SMC_NONE;
      else if (STREQ(argv[i], "--smc-check=some"))
         VG_(clo_smc_check) = VG_CLO_SMC_SOME;
      else if (STREQ(argv[i], "--smc-check=all"))
         VG_(clo_smc_check) = VG_CLO_SMC_ALL;

      else if (STREQ(argv[i], "--trace-syscalls=yes"))
         VG_(clo_trace_syscalls) = True;
      else if (STREQ(argv[i], "--trace-syscalls=no"))
         VG_(clo_trace_syscalls) = False;

      else if (STREQ(argv[i], "--trace-signals=yes"))
         VG_(clo_trace_signals) = True;
      else if (STREQ(argv[i], "--trace-signals=no"))
         VG_(clo_trace_signals) = False;

      else if (STREQ(argv[i], "--trace-symtab=yes"))
         VG_(clo_trace_symtab) = True;
      else if (STREQ(argv[i], "--trace-symtab=no"))
         VG_(clo_trace_symtab) = False;

      else if (STREQ(argv[i], "--trace-malloc=yes"))
         VG_(clo_trace_malloc) = True;
      else if (STREQ(argv[i], "--trace-malloc=no"))
         VG_(clo_trace_malloc) = False;

      else if (STREQ(argv[i], "--trace-sched=yes"))
         VG_(clo_trace_sched) = True;
      else if (STREQ(argv[i], "--trace-sched=no"))
         VG_(clo_trace_sched) = False;

      else if (STREQ(argv[i], "--trace-pthread=none"))
         VG_(clo_trace_pthread_level) = 0;
      else if (STREQ(argv[i], "--trace-pthread=some"))
         VG_(clo_trace_pthread_level) = 1;
      else if (STREQ(argv[i], "--trace-pthread=all"))
         VG_(clo_trace_pthread_level) = 2;

      else if (STREQN(14, argv[i], "--weird-hacks="))
         VG_(clo_weird_hacks) = &argv[i][14];

      else if (STREQN(13, argv[i], "--stop-after="))
         VG_(clo_stop_after) = VG_(atoll)(&argv[i][13]);

      else if (STREQN(13, argv[i], "--dump-error="))
         VG_(clo_dump_error) = (Int)VG_(atoll)(&argv[i][13]);

      else if (STREQN(14, argv[i], "--num-callers=")) {
         /* Make sure it's sane. */
	 VG_(clo_backtrace_size) = (Int)VG_(atoll)(&argv[i][14]);
         if (VG_(clo_backtrace_size) < 2)
            VG_(clo_backtrace_size) = 2;
         if (VG_(clo_backtrace_size) >= VG_DEEPEST_BACKTRACE)
            VG_(clo_backtrace_size) = VG_DEEPEST_BACKTRACE;
      }

      else
         bad_option(argv[i]);
   }

#  undef ISSPACE
#  undef STREQ
#  undef STREQN

   if (VG_(clo_verbosity < 0))
      VG_(clo_verbosity) = 0;

   if (VG_(clo_GDB_attach) && VG_(clo_trace_children)) {
      VG_(message)(Vg_UserMsg, "");
      VG_(message)(Vg_UserMsg, 
         "--gdb-attach=yes conflicts with --trace-children=yes");
      VG_(message)(Vg_UserMsg, 
         "Please choose one or the other, but not both.");
      bad_option("--gdb-attach=yes and --trace-children=yes");
   }

   VG_(clo_logfile_fd) = eventually_logfile_fd;

   /* Don't do memory checking if simulating the cache. */
   if (VG_(clo_cachesim)) {
       VG_(clo_instrument) = False;
   }

   if (VG_(clo_verbosity > 0)) {
      if (VG_(clo_cachesim)) {
         VG_(message)(Vg_UserMsg, 
            "cachegrind-%s, an I1/D1/L2 cache profiler for x86 GNU/Linux.",
            VERSION);
      } else {
         VG_(message)(Vg_UserMsg, 
            "valgrind-%s, a memory error detector for x86 GNU/Linux.",
            VERSION);
      }
   }

   if (VG_(clo_verbosity > 0))
      VG_(message)(Vg_UserMsg, 
                   "Copyright (C) 2000-2002, and GNU GPL'd, by Julian Seward.");
   if (VG_(clo_verbosity) > 1) {
      VG_(message)(Vg_UserMsg, "Startup, with flags:");
      for (i = 0; i < argc; i++) {
         VG_(message)(Vg_UserMsg, "   %s", argv[i]);
      }
   }

   if (VG_(clo_n_suppressions) == 0 && !VG_(clo_cachesim)) {
      config_error("No error-suppression files were specified.");
   }
}


/* ---------------------------------------------------------------------
   Copying to/from m_state_static.
   ------------------------------------------------------------------ */

UInt VG_(m_state_static) [8 /* int regs, in Intel order */ 
                          + 1 /* %eflags */ 
                          + 1 /* %eip */
                          + VG_SIZE_OF_FPUSTATE_W /* FPU state */
                         ];

void VG_(copy_baseBlock_to_m_state_static) ( void )
{
   Int i;
   VG_(m_state_static)[ 0/4] = VG_(baseBlock)[VGOFF_(m_eax)];
   VG_(m_state_static)[ 4/4] = VG_(baseBlock)[VGOFF_(m_ecx)];
   VG_(m_state_static)[ 8/4] = VG_(baseBlock)[VGOFF_(m_edx)];
   VG_(m_state_static)[12/4] = VG_(baseBlock)[VGOFF_(m_ebx)];
   VG_(m_state_static)[16/4] = VG_(baseBlock)[VGOFF_(m_esp)];
   VG_(m_state_static)[20/4] = VG_(baseBlock)[VGOFF_(m_ebp)];
   VG_(m_state_static)[24/4] = VG_(baseBlock)[VGOFF_(m_esi)];
   VG_(m_state_static)[28/4] = VG_(baseBlock)[VGOFF_(m_edi)];

   VG_(m_state_static)[32/4] = VG_(baseBlock)[VGOFF_(m_eflags)];
   VG_(m_state_static)[36/4] = VG_(baseBlock)[VGOFF_(m_eip)];

   for (i = 0; i < VG_SIZE_OF_FPUSTATE_W; i++)
      VG_(m_state_static)[40/4 + i] 
         = VG_(baseBlock)[VGOFF_(m_fpustate) + i];
}


void VG_(copy_m_state_static_to_baseBlock) ( void )
{
   Int i;
   VG_(baseBlock)[VGOFF_(m_eax)] = VG_(m_state_static)[ 0/4];
   VG_(baseBlock)[VGOFF_(m_ecx)] = VG_(m_state_static)[ 4/4];
   VG_(baseBlock)[VGOFF_(m_edx)] = VG_(m_state_static)[ 8/4];
   VG_(baseBlock)[VGOFF_(m_ebx)] = VG_(m_state_static)[12/4];
   VG_(baseBlock)[VGOFF_(m_esp)] = VG_(m_state_static)[16/4];
   VG_(baseBlock)[VGOFF_(m_ebp)] = VG_(m_state_static)[20/4];
   VG_(baseBlock)[VGOFF_(m_esi)] = VG_(m_state_static)[24/4];
   VG_(baseBlock)[VGOFF_(m_edi)] = VG_(m_state_static)[28/4];

   VG_(baseBlock)[VGOFF_(m_eflags)] = VG_(m_state_static)[32/4];
   VG_(baseBlock)[VGOFF_(m_eip)] = VG_(m_state_static)[36/4];

   for (i = 0; i < VG_SIZE_OF_FPUSTATE_W; i++)
      VG_(baseBlock)[VGOFF_(m_fpustate) + i]
         = VG_(m_state_static)[40/4 + i];
}


/* ---------------------------------------------------------------------
   Show accumulated counts.
   ------------------------------------------------------------------ */

static void vg_show_counts ( void )
{
   VG_(message)(Vg_DebugMsg,
		"      lru: %d epochs, %d clearings.",
		VG_(current_epoch),
                VG_(number_of_lrus) );
   VG_(message)(Vg_DebugMsg,
                "translate: new %d (%d -> %d), discard %d (%d -> %d).",
                VG_(overall_in_count),
                VG_(overall_in_osize),
                VG_(overall_in_tsize),
                VG_(overall_out_count),
                VG_(overall_out_osize),
                VG_(overall_out_tsize) );
   VG_(message)(Vg_DebugMsg,
      " dispatch: %lu basic blocks, %d/%d sched events, %d tt_fast misses.", 
      VG_(bbs_done), VG_(num_scheduling_events_MAJOR), 
                     VG_(num_scheduling_events_MINOR), 
                     VG_(tt_fast_misses));
   VG_(message)(Vg_DebugMsg, 
                "reg-alloc: %d t-req-spill, "
                "%d+%d orig+spill uis, %d total-reg-r.",
                VG_(translations_needing_spill),
                VG_(uinstrs_prealloc),
                VG_(uinstrs_spill),
                VG_(total_reg_rank) );
   VG_(message)(Vg_DebugMsg, 
                "   sanity: %d cheap, %d expensive checks.",
                VG_(sanity_fast_count), 
                VG_(sanity_slow_count) );
}


/* ---------------------------------------------------------------------
   Main!
   ------------------------------------------------------------------ */

/* Where we jump to once Valgrind has got control, and the real
   machine's state has been copied to the m_state_static. */

void VG_(main) ( void )
{
   Int               i;
   VgSchedReturnCode src;
   ThreadState*      tst;

   /* Set up our stack sanity-check words. */
   for (i = 0; i < 10; i++) {
      VG_(stack)[i]         = (UInt)(&VG_(stack)[i])         ^ 0xA4B3C2D1;
      VG_(stack)[10000-1-i] = (UInt)(&VG_(stack)[10000-i-1]) ^ 0xABCD4321;
   }

   /* Set up baseBlock offsets and copy the saved machine's state into
      it. */
   vg_init_baseBlock();
   VG_(copy_m_state_static_to_baseBlock)();

   /* Process Valgrind's command-line opts (from env var VG_OPTS). */
   process_cmd_line_options();

   /* Hook to delay things long enough so we can get the pid and
      attach GDB in another shell. */
   if (0) { 
      Int p, q;
      for (p = 0; p < 50000; p++)
         for (q = 0; q < 50000; q++) ;
   }

   /* Initialise the scheduler, and copy the client's state from
      baseBlock into VG_(threads)[1].  This has to come before signal
      initialisations. */
   VG_(scheduler_init)();

   /* Initialise the signal handling subsystem, temporarily parking
      the saved blocking-mask in saved_sigmask. */
   VG_(sigstartup_actions)();

   /* Perhaps we're profiling Valgrind? */
#  ifdef VG_PROFILE
   VGP_(init_profiling)();
#  endif

   /* Start calibration of our RDTSC-based clock. */
   VG_(start_rdtsc_calibration)();

   if (VG_(clo_instrument) || VG_(clo_cachesim)) {
      VGP_PUSHCC(VgpInitAudit);
      VGM_(init_memory_audit)();
      VGP_POPCC;
   }

   VGP_PUSHCC(VgpReadSyms);
   VG_(read_symbols)();
   VGP_POPCC;

   /* End calibration of our RDTSC-based clock, leaving it as long as
      we can. */
   VG_(end_rdtsc_calibration)();

   /* This should come after init_memory_audit; otherwise the latter
      carefully sets up the permissions maps to cover the anonymous
      mmaps for the translation table and translation cache, which
      wastes > 20M of virtual address space. */
   VG_(init_tt_tc)();

   if (VG_(clo_verbosity) == 1) {
      VG_(message)(Vg_UserMsg, 
                   "For more details, rerun with: -v");
   }

   /* Now it is safe for malloc et al in vg_clientmalloc.c to act
      instrumented-ly. */
   VG_(running_on_simd_CPU) = True;
   if (VG_(clo_instrument)) {
      VGM_(make_readable) ( (Addr)&VG_(running_on_simd_CPU), 1 );
      VGM_(make_readable) ( (Addr)&VG_(clo_instrument), 1 );
      VGM_(make_readable) ( (Addr)&VG_(clo_trace_malloc), 1 );
      VGM_(make_readable) ( (Addr)&VG_(clo_sloppy_malloc), 1 );
   }

   if (VG_(clo_cachesim)) 
      VG_(init_cachesim)();

   if (VG_(clo_verbosity) > 0)
      VG_(message)(Vg_UserMsg, "");

   VG_(bbs_to_go) = VG_(clo_stop_after);

   /* Run! */
   VGP_PUSHCC(VgpSched);
   src = VG_(scheduler)();
   VGP_POPCC;

   if (VG_(clo_verbosity) > 0)
      VG_(message)(Vg_UserMsg, "");

   if (src == VgSrc_Deadlock) {
     VG_(message)(Vg_UserMsg, 
        "Warning: pthread scheduler exited due to deadlock");
   }

   if (VG_(clo_instrument)) {
      VG_(show_all_errors)();
      VG_(clientmalloc_done)();
      if (VG_(clo_verbosity) == 1) {
         VG_(message)(Vg_UserMsg, 
                      "For counts of detected errors, rerun with: -v");
      }
      if (VG_(clo_leak_check)) VG_(detect_memory_leaks)();
   }
   VG_(running_on_simd_CPU) = False;

   if (VG_(clo_cachesim))
      VG_(show_cachesim_results)(VG_(client_argc), VG_(client_argv));

   VG_(do_sanity_checks)( True /*include expensive checks*/ );

   if (VG_(clo_verbosity) > 1)
      vg_show_counts();

   if (0) {
      VG_(message)(Vg_DebugMsg, "");
      VG_(message)(Vg_DebugMsg, 
         "------ Valgrind's internal memory use stats follow ------" );
      VG_(mallocSanityCheckAll)();
      VG_(show_all_arena_stats)();
      VG_(message)(Vg_DebugMsg, 
         "------ Valgrind's ExeContext management stats follow ------" );
      VG_(show_ExeContext_stats)();
      VG_(message)(Vg_DebugMsg, 
         "------ Valgrind's client block stats follow ---------------" );
      VG_(show_client_block_stats)();
   }
 
#  ifdef VG_PROFILE
   VGP_(done_profiling)();
#  endif

   VG_(done_prof_mem)();

   VG_(shutdown_logging)();

   /* Remove valgrind.so from a LD_PRELOAD=... string so child
      processes don't get traced into.  Also mess up $libdir/valgrind
      so that our libpthread.so disappears from view. */
   if (!VG_(clo_trace_children)) { 
      VG_(mash_LD_PRELOAD_and_LD_LIBRARY_PATH)(
         VG_(getenv)("LD_PRELOAD"),
         VG_(getenv)("LD_LIBRARY_PATH") 
      );
   }

   /* Decide how to exit.  This depends on what the scheduler
      returned. */
   switch (src) {
      case VgSrc_ExitSyscall: /* the normal way out */
         vg_assert(VG_(last_run_tid) > 0 
                   && VG_(last_run_tid) < VG_N_THREADS);
         tst = & VG_(threads)[VG_(last_run_tid)];
         vg_assert(tst->status == VgTs_Runnable);
         /* The thread's %EBX will hold the arg to exit(), so we just
            do exit with that arg. */
         VG_(exit)( tst->m_ebx );
         /* NOT ALIVE HERE! */
         VG_(panic)("entered the afterlife in vg_main() -- ExitSyscall");
         break; /* what the hell :) */

      case VgSrc_Deadlock:
         /* Just exit now.  No point in continuing. */
         VG_(exit)(0);
         VG_(panic)("entered the afterlife in vg_main() -- Deadlock");
         break;

      case VgSrc_BbsDone: 
         /* Tricky; we have to try and switch back to the real CPU.
            This is all very dodgy and won't work at all in the
            presence of threads, or if the client happened to be
            running a signal handler. */
         /* Prepare to restore state to the real CPU. */
         VG_(load_thread_state)(1 /* root thread */ );
         VG_(copy_baseBlock_to_m_state_static)();

         /* This pushes a return address on the simulator's stack,
            which is abandoned.  We call vg_sigshutdown_actions() at
            the end of vg_switch_to_real_CPU(), so as to ensure that
            the original stack and machine state is restored before
            the real signal mechanism is restored.  */
         VG_(switch_to_real_CPU)();

      default:
         VG_(panic)("vg_main(): unexpected scheduler return code");
   }
}


/* Debugging thing .. can be called from assembly with OYNK macro. */
void VG_(oynk) ( Int n )
{
   OINK(n);
}


/* Find "valgrind.so" in a LD_PRELOAD=... string, and convert it to
   "valgrinq.so", which doesn't do anything.  This is used to avoid
   tracing into child processes.  To make this work the build system
   also supplies a dummy file, "valgrinq.so". 

   Also look for $(libdir)/lib/valgrind in LD_LIBRARY_PATH and change
   it to $(libdir)/lib/valgrinq, so as to make our libpthread.so
   disappear.  
*/
void VG_(mash_LD_PRELOAD_and_LD_LIBRARY_PATH) ( Char* ld_preload_str,
                                                Char* ld_library_path_str )
{
   Char* p_prel = NULL;
   Char* p_path = NULL;
   Int   what = 0;
   if (ld_preload_str == NULL || ld_library_path_str == NULL)
      goto mutancy;

   /* VG_(printf)("%s %s\n", ld_preload_str, ld_library_path_str); */

   p_prel = VG_(strstr)(ld_preload_str, "valgrind.so");
   p_path = VG_(strstr)(ld_library_path_str, VG_LIBDIR);

   if (p_prel == NULL) {
      /* perhaps already happened? */
      what = 1;
      if (VG_(strstr)(ld_preload_str, "valgrinq.so") == NULL)
         goto mutancy;
      if (VG_(strstr)(ld_library_path_str, "lib/valgrinq") == NULL)
         goto mutancy;
      return;
   }

   what = 2;
   if (p_path == NULL) goto mutancy;

   /* in LD_PRELOAD, turn valgrind.so into valgrinq.so. */
   what = 3;
   if (p_prel[7] != 'd') goto mutancy;
   p_prel[7] = 'q';

   /* in LD_LIBRARY_PATH, turn $libdir/valgrind (as configure'd) from 
      .../lib/valgrind .../lib/valgrinq, which doesn't exist,
      so that our own libpthread.so goes out of scope. */
   p_path += VG_(strlen)(VG_LIBDIR);
   what = 4;
   if (p_path[0] != '/') goto mutancy;
   p_path++; /* step over / */
   what = 5;
   if (p_path[7] != 'd') goto mutancy;
   p_path[7] = 'q';
   return;

  mutancy:
   VG_(printf)(
      "\nVG_(mash_LD_PRELOAD_and_LD_LIBRARY_PATH): internal error:\n"
      "   what                = %d\n"
      "   ld_preload_str      = `%s'\n"
      "   ld_library_path_str = `%s'\n"
      "   p_prel              = `%s'\n"
      "   p_path              = `%s'\n"
      "   VG_LIBDIR           = `%s'\n",
       what, ld_preload_str, ld_library_path_str, p_prel, p_path, VG_LIBDIR );
   VG_(panic)("VG_(mash_LD_PRELOAD_and_LD_LIBRARY_PATH) failed\n");
}


/* RUNS ON THE CLIENT'S STACK, but on the real CPU.  Start GDB and get
   it to attach to this process.  Called if the user requests this
   service after an error has been shown, so she can poke around and
   look at parameters, memory, etc.  You can't meaningfully get GDB to
   continue the program, though; to continue, quit GDB.  */
extern void VG_(start_GDB_whilst_on_client_stack) ( void )
{
   Int   res;
   UChar buf[100];
   VG_(sprintf)(buf,
                "/usr/bin/gdb -nw /proc/%d/exe %d", 
                VG_(getpid)(), VG_(getpid)());
   VG_(message)(Vg_UserMsg, "starting GDB with cmd: %s", buf);
   res = VG_(system)(buf);
   if (res == 0) {      
      VG_(message)(Vg_UserMsg, "");
      VG_(message)(Vg_UserMsg, 
         "GDB has detached.  Valgrind regains control.  We continue.");
   } else {
      VG_(message)(Vg_UserMsg, "Apparently failed!");
      VG_(message)(Vg_UserMsg, "");
   }
}


/* Print some helpful-ish text about unimplemented things, and give
   up. */
void VG_(unimplemented) ( Char* msg )
{
   VG_(message)(Vg_UserMsg, "");
   VG_(message)(Vg_UserMsg, 
      "Valgrind detected that your program requires");
   VG_(message)(Vg_UserMsg, 
      "the following unimplemented functionality:");
   VG_(message)(Vg_UserMsg, "   %s", msg);
   VG_(message)(Vg_UserMsg,
      "This may be because the functionality is hard to implement,");
   VG_(message)(Vg_UserMsg,
      "or because no reasonable program would behave this way,");
   VG_(message)(Vg_UserMsg,
      "or because nobody has yet needed it.  In any case, let me know");
   VG_(message)(Vg_UserMsg,
      "(jseward@acm.org) and/or try to work around the problem, if you can.");
   VG_(message)(Vg_UserMsg,
      "");
   VG_(message)(Vg_UserMsg,
      "Valgrind has to exit now.  Sorry.  Bye!");
   VG_(message)(Vg_UserMsg,
      "");
   VG_(pp_sched_status)();
   VG_(exit)(1);
}


void VG_(nvidia_moan) ( void) 
{
   VG_(message)(Vg_UserMsg,
      "The following failure _might_ be caused by linking to NVidia's\n   "
      "libGL.so, so avoiding it, if you can, _might_ help you.  For example,\n   "
      "re-build any Qt libraries you are using without OpenGL support.");
}


/*--------------------------------------------------------------------*/
/*--- end                                                vg_main.c ---*/
/*--------------------------------------------------------------------*/