[Bug gcov-profile/90053] New: [GCOV] A statement in while loop is wrongly marked as not executed when they are within the if(setjmp()) statement

[yangyibiao at nju dot edu.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90053

            Bug ID: 90053
           Summary: [GCOV] A statement in while loop is wrongly marked as
                    not executed when they are within the if(setjmp())
                    statement
           Product: gcc
           Version: 8.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: gcov-profile
          Assignee: unassigned at gcc dot gnu.org
          Reporter: yangyibiao at nju dot edu.cn
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/8/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
8.2.0-1ubuntu2~18.04' --with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie
--with-system-zlib --with-target-system-zlib --enable-objc-gc=auto
--enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none --without-cuda-driver
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 8.2.0 (Ubuntu 8.2.0-1ubuntu2~18.04)

$ cat small.c
#include <setjmp.h>
#include <signal.h>
#include <stdlib.h>

static jmp_buf segv_jmpbuf;
static void segv_handler(int seg) {  __builtin_longjmp(segv_jmpbuf, 1); }

static int is_addressable(void *p, size_t size)
{
   volatile char * volatile cp = (volatile char *)p;
   volatile int ret;
   struct sigaction sa, origsa;
   sigset_t mask;

   sa.sa_handler = segv_handler;
   sa.sa_flags = 0;
   sigfillset(&sa.sa_mask);
   sigaction(SIGSEGV, &sa, &origsa);
   sigprocmask(SIG_SETMASK, NULL, &mask);

   if (__builtin_setjmp(segv_jmpbuf) == 0) {
      printf("size: %d\n", size);
      while(size--)
      {  *cp++; }
      ret = 1;
   } else {
      ret = 0;
   }

   sigaction(SIGSEGV, &origsa, NULL);
   sigprocmask(SIG_SETMASK, &mask, NULL);

   return ret;
}

int main(int argc, char **argv)
{
   is_addressable(0x0, 1);
   return 0;
}

$ gcc -w -O0 --coverage small.c; ./a.out; gcov-8 small.c; cat small.c.gcov
size: 1
File 'small.c'
Lines executed:95.00% of 20
Creating 'small.c.gcov'

        -:    0:Source:small.c
        -:    0:Graph:small.gcno
        -:    0:Data:small.gcda
        -:    0:Runs:1
        -:    0:Programs:1
        -:    1:#include <setjmp.h>
        -:    2:#include <signal.h>
        -:    3:#include <stdlib.h>
        -:    4:
        -:    5:static jmp_buf segv_jmpbuf;
        1:    6:static void segv_handler(int seg) { 
__builtin_longjmp(segv_jmpbuf, 1); }
        -:    7:
        1:    8:static int is_addressable(void *p, size_t size)
        -:    9:{
        1:   10:   volatile char * volatile cp = (volatile char *)p;
        -:   11:   volatile int ret;
        -:   12:   struct sigaction sa, origsa;
        -:   13:   sigset_t mask;
        -:   14:
        1:   15:   sa.sa_handler = segv_handler;
        1:   16:   sa.sa_flags = 0;
        1:   17:   sigfillset(&sa.sa_mask);
        1:   18:   sigaction(SIGSEGV, &sa, &origsa);
        1:   19:   sigprocmask(SIG_SETMASK, NULL, &mask);
        -:   20:
        2:   21:   if (__builtin_setjmp(segv_jmpbuf) == 0) {
        1:   22:      printf("size: %d\n", size);
        1:   23:      while(size--)
    #####:   24:      {  *cp++; }
        1:   25:      ret = 1;
        -:   26:   } else {
        1:   27:      ret = 0;
        -:   28:   }
        -:   29:
        2:   30:   sigaction(SIGSEGV, &origsa, NULL);
        1:   31:   sigprocmask(SIG_SETMASK, &mask, NULL);
        -:   32:
        1:   33:   return ret;
        -:   34:}
        -:   35:
        1:   36:int main(int argc, char **argv)
        -:   37:{
        1:   38:   is_addressable(0x0, 1);
        1:   39:   return 0;
        -:   40:}

Line #24 is wrongly marked as not executed. The value of variable #size# is 1
before executing the while statement. Thus, Line #24 should be executed.