Re: [PATCH] eh_personality.cc: unwinding on ARM

[Peter Waechtler]

On 19.03.2012 17:38, Daniel Jacobowitz wrote:

On Mon, Mar 19, 2012 at 12:12 PM, Andrew Stubbs<a...@codesourcery.com>  wrote:

On 16/03/12 13:29, EXTERNAL Waechtler Peter (Fa. TCP, CM-AI/PJ-CF31) wrote:

The CodeSourcery toolchain contains a "fix" like the following,
please consider for adding it.

Here's the full original patch with ChangeLog.

I don't know why Dan never submitted this one. Perhaps it's not suitable for
upstream or not considered the correct fix?

I think it was just a pain to write a test for.

Here's another version using siglongjmp to avoid VERIFY in signal handler:
Can someone (maybe you) put that at the appropriate place?
Please don't let the integration being a pain as well

        Peter

seehttp://gcc.gnu.org/ml/gcc-patches/2012-03/msg01161.html


/*
        author: Peter Waechtler (pwaechtler at mac.com)
        Copyright FSF or whatever is needed

        A simple test case to verify if backtrace(3) goes into
        a loop while unwinding on ARM with cxx_personality routine.
*/
#include<unistd.h>
#include<stdlib.h>
#include<string.h>
#include<signal.h>
#include<execinfo.h>
#include<setjmp.h>

#include<iostream>
#include<vector>
using namespace std;

//#include "testsuite.h"

#define WE_PASSED 42
#define WE_FAILED 0xff

sigjmp_buf env;

static void abort_handler(int n_signal, siginfo_t *siginfo, void *ptr)
{
        void *address[20];
        int depth;

        depth = backtrace(address, sizeof(address)/sizeof(void*));

        backtrace_symbols_fd(address, depth, 0);
        /* this is a dumb check, better look for main */
        if (depth == sizeof(address)/sizeof(void*))
                siglongjmp(env, WE_FAILED);
        else
                siglongjmp(env, WE_PASSED);
}

static int tst_eh01(void)
{
        int rc = 0;

        std::vector<int>   v(10);
        rc = v.at(42);

        return rc;
}

int main(int argc, char *argv[])
{
        int c = 1;
        struct sigaction sa;

        memset(&sa, 0 , sizeof(sa));
        sa.sa_sigaction = abort_handler;
        sa.sa_flags = SA_SIGINFO;

        sigaction(SIGABRT,&sa, NULL);

        switch (sigsetjmp(env, 1)) {
                case 0: /* the context was set */
                        c = tst_eh01();
                        break;
                case WE_PASSED:
                        // VERIFY( true );
                        cerr<<  "PASSED"<<  endl;
                        break;
                default:
                        // VERIFY( false );
                        cerr<<  "FAILED"<<  endl;
                        break;
        }

        return c;
}