[Rd] Latest R-devel fails to compile with --enable-strict-barrier

[Ivan Krylov]

Hello R developers,

'.../configure --enable-strict-barrier && make' eventually fails to
load tools.so due to an undefined reference to OBJECT().

Judging by the disassembly, the call surfaces in deparseRd(), close to
the beginning of the function:

    if(!isString(e) || LENGTH(e) != 1) 
        error(_("'deparseRd' only supports deparsing character elements"));
    e = STRING_ELT(e, 0);
    return (TYPEOF(s) == INTSXP && !inherits(s, "factor"));
    if(!isInteger(state) || LENGTH(state) != 5) error(_("bad state"));

    if (OBJECT(s)) {
   12828:       48 89 df                mov    %rbx,%rdi
   1282b:       e8 d0 19 ff ff          call   4200 <OBJECT using plt>
   12830:       85 c0                   test   %eax,%eax
   12832:       0f 85 57 03 00 00       jne    12b8f <deparseRd+0x3df>
...
        klass = getAttrib(s, R_ClassSymbol);
   12b8f:       48 8b 05 ca 73 00 00    mov    0x73ca(%rip),%rax # R_ClassSymbol
   12b96:       48 89 df                mov    %rbx,%rdi
   12b99:       48 8b 30                mov    (%rax),%rsi
   12b9c:       e8 3f 1b ff ff          call   46e0 <Rf_getAttrib using plt>

Looking at the preprocessor output, I think that the call to OBJECT()
appears through the inlined function isInteger(), which calls inlined
function inherits(), which contains the call to OBJECT(), which is not
available to the 'tools' shared library due to being newly hidden.

Without strict barrier checking, OBJECT(s) gets expanded to
((s)->sxpinfo.obj), and all works well.

-- 
Best regards,
Ivan