usr/src/lib/libc/gmon/gmon.c

static  char *sccsid = "@(#)gmon.c      4.3 (Berkeley) %G%";

#ifdef DEBUG
#include <stdio.h>
#endif DEBUG

#include "gcrt0.h"

    /*
     *  C start up routines, for monitoring
     *  Robert Henry, UCB, 20 Oct 81
     *
     *  We make the following (true) assumptions:
     *  1) when the kernel calls start, it does a jump to location 2,
     *  and thus avoids the register save mask.  We are NOT called
     *  with a calls!  see sys1.c:setregs().
     *  2) The only register variable that we can trust is sp,
     *  which points to the base of the kernel calling frame.
     *  Do NOT believe the documentation in exec(2) regarding the
     *  values of fp and ap.
     *  3) We can allocate as many register variables as we want,
     *  and don't have to save them for anybody.
     *  4) Because of the ways that asm's work, we can't have
     *  any automatic variables allocated on the stack, because
     *  we must catch the value of sp before any automatics are
     *  allocated.
     */

char **environ;
    /*
     *  etext is added by the loader, and is the end of the text space.
     *  eprol is a local symbol, and labels almost the beginning of text space.
     *      its name is changed so it doesn't look like a function.
     */
extern  unsigned char   etext;
extern  unsigned char   eprol;
asm( "#define _eprol _$eprol" );

asm( "#define _start start" );
start()
{
    struct kframe {
        int     kargc;
        char    *kargv[1];              /* size depends on kargc */
        char    kargstr[1];             /* size varies */
        char    kenvstr[1];             /* size varies */
    };
        /*
         *      ALL REGISTER VARIABLES!!!
         */
    register struct kframe      *kfp;           /* r11 */
    register char               **targv;
    register char               **argv;

#ifdef lint
    kfp = 0;
#else not lint
    asm( "      movl    sp,r11" );              /* catch it quick */
#endif not lint
    for ( argv = targv = &kfp -> kargv[0] ; *targv++ ; /* void */ )
        /* VOID */ ;
    if ( targv >= (char **) ( *argv ) )
        --targv;
    environ = targv;
asm("_eprol:");
    _mstartup( &eprol , &etext );
    exit( main( kfp -> kargc , argv , environ ) );
}
asm( "#undef _start" );
asm( "#undef _eprol" );

exit( code )
        /* ARGSUSED */
    register int        code;   /* r11 */
{

    _mcleanup();
    _cleanup();
    asm( "      movl r11, r0" );
    asm( "      chmk $1" );
}

    /*
     *  froms is actually a bunch of unsigned shorts indexing tos
     */
static unsigned short   *froms;
static struct tostruct  *tos = 0;
static unsigned short   tolimit = 0;
static char             *s_lowpc = 0;
static char             *s_highpc = 0;
static unsigned long    s_textsize = 0;
static char             *minsbrk = 0;

static int      ssiz;
static int      *sbuf;

#define MSG "No space for monitor buffer(s)\n"

_mstartup(lowpc, highpc)
    char        *lowpc;
    char        *highpc;
{
    int                 monsize;
    char                *buffer;
    char                *sbrk();
    unsigned long       limit;

    s_lowpc = lowpc;
    s_highpc = highpc;
    s_textsize = highpc - lowpc;
    monsize = s_textsize + sizeof(struct phdr);
    buffer = sbrk( monsize );
    if ( buffer == (char *) -1 ) {
        write( 2 , MSG , sizeof(MSG) );
        return;
    }
    froms = (unsigned short *) sbrk( s_textsize );
    if ( froms == (unsigned short *) -1 ) {
        write( 2 , MSG , sizeof(MSG) );
        froms = 0;
        return;
    }
    tos = (struct tostruct *) sbrk(s_textsize);
    if ( tos == (struct tostruct *) -1 ) {
        write( 2 , MSG , sizeof(MSG) );
        froms = 0;
        tos = 0;
        return;
    }
    tos[0].link = 0;
    limit = s_textsize / sizeof(struct tostruct);
        /*
         *      tolimit is what mcount checks to see if
         *      all the data structures are ready!!!
         *      make sure it won't overflow.
         */
    tolimit = limit > 65534 ? 65534 : limit;
    monitor( lowpc , highpc , buffer , monsize );
}

_mcleanup()
{
    int                 fd;
    int                 fromindex;
    char                *frompc;
    int                 toindex;
    struct rawarc       rawarc;

    monitor( (int (*)()) 0 );
    fd = creat( "gmon.out" , 0666 );
    if ( fd < 0 ) {
        perror( "mcount: gmon.out" );
        return;
    }
#   ifdef DEBUG
        fprintf( stderr , "[mcleanup] sbuf 0x%x ssiz %d\n" , sbuf , ssiz );
#   endif DEBUG
    write( fd , sbuf , ssiz );
    for ( fromindex = 0 ; fromindex < s_textsize>>1 ; fromindex++ ) {
        if ( froms[fromindex] == 0 ) {
            continue;
        }
        frompc = s_lowpc + (fromindex<<1);
        for (toindex=froms[fromindex]; toindex!=0; toindex=tos[toindex].link) {
#           ifdef DEBUG
                fprintf( stderr ,
                        "[mcleanup] frompc 0x%x selfpc 0x%x count %d\n" ,
                        frompc , tos[toindex].selfpc , tos[toindex].count );
#           endif DEBUG
            rawarc.raw_frompc = (unsigned long) frompc;
            rawarc.raw_selfpc = (unsigned long) tos[toindex].selfpc;
            rawarc.raw_count = tos[toindex].count;
            write( fd , &rawarc , sizeof rawarc );
        }
    }
    close( fd );
}

    /*
     *  This routine is massaged so that it may be jsb'ed to
     */
asm("#define _mcount mcount");
mcount()
{
    register char               *selfpc;        /* r11 */
    register unsigned short     *frompcindex;   /* r10 */
    register struct tostruct    *top;           /* r9 */
    static int                  profiling = 0;

    asm( "      forgot to run ex script on gcrt0.s" );
    asm( "#define r11 r5" );
    asm( "#define r10 r4" );
    asm( "#define r9 r3" );
#ifdef lint
    selfpc = (char *) 0;
    frompcindex = 0;
#else not lint
        /*
         *      find the return address for mcount,
         *      and the return address for mcount's caller.
         */
    asm("       movl (sp), r11");       /* selfpc = ... (jsb frame) */
    asm("       movl 16(fp), r10");     /* frompcindex =     (calls frame) */
#endif not lint
        /*
         *      check that we are profiling
         *      and that we aren't recursively invoked.
         */
    if ( tolimit == 0 ) {
        goto out;
    }
    if ( profiling ) {
        goto out;
    }
    profiling = 1;
        /*
         *      check that frompcindex is a reasonable pc value.
         *      for example:    signal catchers get called from the stack,
         *                      not from text space.  too bad.
         */
    frompcindex = (unsigned short *) ( (long) frompcindex - (long) s_lowpc );
    if ( (unsigned long) frompcindex > s_textsize ) {
        goto done;
    }
    frompcindex = &froms[ ( (long) frompcindex ) >> 1 ];
    if ( *frompcindex == 0 ) {
        *frompcindex = ++tos[0].link;
        if ( *frompcindex >= tolimit ) {
            goto overflow;
        }
        top = &tos[ *frompcindex ];
        top->selfpc = selfpc;
        top->count = 0;
        top->link = 0;
    } else {
        top = &tos[ *frompcindex ];
    }
    for ( ; /* goto done */ ; top = &tos[ top -> link ] ) {
        if ( top -> selfpc == selfpc ) {
            top -> count++;
            goto done;
        }
        if ( top -> link == 0 ) {
            top -> link = ++tos[0].link;
            if ( top -> link >= tolimit )
                goto overflow;
            top = &tos[ top -> link ];
            top -> selfpc = selfpc;
            top -> count = 1;
            top -> link = 0;
            goto done;
        }
    }
done:
    profiling = 0;
    /* and fall through */
out:
    asm( "      rsb" );
    asm( "#undef r11" );
    asm( "#undef r10" );
    asm( "#undef r9" );
    asm( "#undef _mcount");

overflow:
    tolimit = 0;
#   define      TOLIMIT "mcount: tos overflow\n"
    write( 2 , TOLIMIT , sizeof( TOLIMIT ) );
    goto out;
}

monitor( lowpc , highpc , buf , bufsiz )
    char        *lowpc;
    /* VARARGS1 */
    char        *highpc;
    int         *buf, bufsiz;
{
    register o;

    if ( lowpc == 0 ) {
        profil( (char *) 0 , 0 , 0 , 0 );
        return;
    }
    sbuf = buf;
    ssiz = bufsiz;
    ( (struct phdr *) buf ) -> lpc = lowpc;
    ( (struct phdr *) buf ) -> hpc = highpc;
    ( (struct phdr *) buf ) -> ncnt = ssiz;
    o = sizeof(struct phdr);
    buf = (int *) ( ( (int) buf ) + o );
    bufsiz -= o;
    if ( bufsiz <= 0 )
        return;
    o = ( ( (char *) highpc - (char *) lowpc) );
    if( bufsiz < o )
        o = ( (float) bufsiz / o ) * 65536;
    else
        o = 65536;
    profil( buf , bufsiz , lowpc , o );
}

/*
 * This is a stub for the "brk" system call, which we want to
 * catch so that it will not deallocate our data space.
 * (of which the program is not aware)
 */
asm("#define _curbrk curbrk");
extern char *curbrk;

brk(addr)
        char *addr;
{

        if (addr < minsbrk)
                addr = minsbrk;
        asm("   chmk    $17");
        asm("   jcs     cerror");
        curbrk = addr;
        return (0);
}