[Bug jit/103199] New: FAIL: ../jit/docs/examples/tut04-toyvm/toyvm.c, initial compilation

[Bug jit/103199] New: FAIL: ../jit/docs/examples/tut04-toyvm/toyvm.c, initial compilation

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103199

            Bug ID: 103199
           Summary: FAIL: ../jit/docs/examples/tut04-toyvm/toyvm.c,
                    initial compilation
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: jit
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: msebor at gcc dot gnu.org
  Target Milestone: ---

A recent regression test run shows FAILs in a couple of JIT example programs,
both due to -Wformat-overflow errors:

/build/gcc-master/gcc/testsuite/jit/jit.log:/src/gcc/master/gcc/testsuite/../jit/docs/examples/tut04-toyvm/toyvm.c:
In function 'toyvm_function_compile':
/build/gcc-master/gcc/testsuite/jit/jit.log:/src/gcc/master/gcc/testsuite/../jit/docs/examples/tut04-toyvm/toyvm.c:565:29:
error: 'sprintf' may write a terminating nul past the end of the destination
[-Werror=format-overflow=]
/build/gcc-master/gcc/testsuite/jit/jit.log:/src/gcc/master/gcc/testsuite/../jit/docs/examples/tut04-toyvm/toyvm.c:565:7:
note: 'sprintf' output between 7 and 17 bytes into a destination of size 16
/build/gcc-master/gcc/testsuite/jit/jit.log:/src/gcc/master/gcc/testsuite/../jit/docs/examples/tut04-toyvm/toyvm.cc:
In member function 'void compilation_state::create_function(const char*)':
/build/gcc-master/gcc/testsuite/jit/jit.log:/src/gcc/master/gcc/testsuite/../jit/docs/examples/tut04-toyvm/toyvm.cc:637:29:
error: 'sprintf' may write a terminating nul past the end of the destination
[-Werror=format-overflow=]
/build/gcc-master/gcc/testsuite/jit/jit.log:/src/gcc/master/gcc/testsuite/../jit/docs/examples/tut04-toyvm/toyvm.cc:637:15:
note: 'sprintf' output between 7 and 17 bytes into a destination of size 16

My best guess is that the recent change to convert the strlen pass away from
EVRP to ranger has enabled the warning thanks to better range info.  Looking at
one of the call sites:

  /* Create a block per operation.  */
  for (pc = 0; pc < fn->fn_num_ops; pc++)
    {
      char buf[16];
      sprintf (buf, "instr%i", pc);
      state.op_blocks[pc] = gcc_jit_function_new_block (state.fn, buf);
    }

the buffer is just big enough to fit the string and a 32-bit nonnegative int. 
But pc is a signed int and if its range as determined by ranger includes
negative values the warning will trigger.

[Bug jit/103199] FAIL: ../jit/docs/examples/tut04-toyvm/toyvm.c, initial compilation

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103199

--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by David Malcolm <dmalcolm@gcc.gnu.org>:

https://gcc.gnu.org/g:aa1fd30df56d752e3d5a81af409875a1f1e3e327

commit r12-5196-gaa1fd30df56d752e3d5a81af409875a1f1e3e327
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Thu Nov 11 18:32:21 2021 -0500

    jit: fix -Werror=format-overflow= in testsuite [PR103199]

    gcc/jit/ChangeLog:
            PR jit/103199
            * docs/examples/tut04-toyvm/toyvm.c (toyvm_function_compile):
            Increase size of buffer.
            * docs/examples/tut04-toyvm/toyvm.cc
            (compilation_state::create_function): Likewise.

    Signed-off-by: David Malcolm <dmalcolm@redhat.com>

[Bug jit/103199] FAIL: ../jit/docs/examples/tut04-toyvm/toyvm.c, initial compilation

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103199

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #2 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Thanks; should be fixed by the above commit.