wjb/evaluation/pin-3.15-98253-gb56e429b1-gcc-linux/source/tools/SignalTests/fpcheck.c

/*
 * Copyright 2002-2019 Intel Corporation.
 * 
 * This software is provided to you as Sample Source Code as defined in the accompanying
 * End User License Agreement for the Intel(R) Software Development Products ("Agreement")
 * section 1.L.
 * 
 * This software and the related documents are provided as is, with no express or implied
 * warranties, other than those that are expressly stated in the License.
 */

/*
 * This test verifies that Pin properly saves and restores the applicaton's
 * FP state when emulating a delivered signal.  The application's main thread
 * simply does some FP calculation in a loop while ALRM signals are handled.
 * The signal handler also does some FP computation, which will change the
 * FP state.  If Pin doesn't properly save/restore the FP state, the handler
 * will mess up the main thread's calculations.
 *
 *********************************************************************************
 *
 * I have observed that this test occasionally fails on vs-lin64-4 (running SUSE10
 * on Intel64).  The cause of the problem is probably the same as the bug
 * described at the top of "xmmcheck.c".
 */

#include <stdlib.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <signal.h>
#include <sys/time.h>

#define COUNT   100

volatile unsigned SigCount = 0;


static double fpcheck();
static void handle1(int);
static void handle2(int, siginfo_t *, void *);


int main()
{
    struct sigaction sigact;
    struct itimerval itval;
    double fact;
    char buf[100];
    char *point;


    printf("Before sigaction call\n");
    sigact.sa_handler = handle1;
    sigact.sa_flags = 0;
    sigemptyset(&sigact.sa_mask);
    if (sigaction(SIGALRM, &sigact, 0) == -1)
    {
        fprintf(stderr, "Unable to set up handler\n");
        return 1;
    }

    printf("Before setitimer\n");
    itval.it_interval.tv_sec = 0;
    itval.it_interval.tv_usec = 10000;
    itval.it_value.tv_sec = 0;
    itval.it_value.tv_usec = 10000;
    if (setitimer(ITIMER_REAL, &itval, 0) == -1)
    {
        fprintf(stderr, "Unable to set up timer\n");
        return 1;
    }

    printf("Before fpcheck\n");
    fact = fpcheck();
    printf("After fpcheck\n");

    itval.it_value.tv_sec = 0;
    itval.it_value.tv_usec = 0;
    if (setitimer(ITIMER_REAL, &itval, 0) == -1)
    {
        fprintf(stderr, "Unable to disable timer\n");
        return 1;
    }

    sprintf(buf, "%.0f", fact);
    point = strchr(buf, '.');
    if (point)
        *point = '\0';
    if (strcmp(buf, "1307674368000") != 0)
    {
        fprintf(stderr, "15! should be 1307674368000, but computed as '%s'\n", buf);
        return 1;
    }
    printf("15! = %s\n", buf);
    return 0;
}


static double fpcheck()
{
    double x[15];
    double fact, calc;
    unsigned i;


    for (i = 1;  i <= 15;  i++)
        x[i-1] = (double)i;

    fact = 1.0;
    for (i = 0;  i < 15;  i++)
        fact = fact * x[15 - (i+1)];

    while (SigCount < COUNT)
    {
        calc = 1.0;
        for (i = 0;  i < 15;  i++)
            calc = calc * x[15 - (i+1)];
        if ((calc - fact > 0.5) || (calc - fact < -0.5))
        {
            fprintf(stderr, "Unexpected FP change (fact=%f, calc=%f)\n", fact, calc);
            return 1;
        }
    }

    return fact;
}


static void handle1(int sig)
{
    SigCount++;
    double x[100];
    unsigned i;


    fprintf(stderr, "handle1: %d\n", SigCount);

    for (i = 0;  i < 100;  i++)
        x[i] = (double)(i+1);
    for (i = 2;  i < 100;  i++)
        x[i] = x[i] / x[i-1] * x[i-2] + x[i];

    /*
     * After a while, switch to using a "siginfo" handler.  This exercises different
     * signal emulation paths within Pin.
     */
    if (SigCount > COUNT/2)
    {
        struct sigaction sigact;

        sigact.sa_sigaction = handle2;
        sigact.sa_flags = SA_SIGINFO;
        sigemptyset(&sigact.sa_mask);
        if (sigaction(SIGALRM, &sigact, 0) == -1)
        {
            fprintf(stderr, "Unable to reset handler\n");
            exit(1);
        }
    }
}


static void handle2(int sig, siginfo_t *si, void *v)
{
    double x[100];
    unsigned i;

    SigCount++;

    fprintf(stderr, "handle1: %d\n", SigCount);

    for (i = 0;  i < 100;  i++)
        x[i] = (double)(i+1);
    for (i = 2;  i < 100;  i++)
        x[i] = x[i] / x[i-1] * x[i-2] + x[i];
}