Dear all, the first part of the patch came with a testcase that also exercised code for constant string arguments, which was not touched by that patch but seems to have caused runtime failures on big-endian platforms (e.g. Power-* BE) for all optimization levels, and on x86 / -m32 at -O1 and higher (not at -O0).
I did not see any issues on x86 / -m64 and any optimization level, but could reproduce a problem with x86 / -m32 at -O1, which appears to be related how arguments that are to be passed by value are handled when there is a mismatch between the function prototype and the passed argument. The solution is to truncate too long constant string arguments, fixed by the attached patch, pushed as: https://gcc.gnu.org/g:3f97d10aa1ff5984d6fd657f246d3f251b254ff1 and see attached. * * * I found gcc-testresults quite helpful in checking whether my patch caused trouble on architectures different from the one I'm working on. The value (pun intended) would have been even greater if output of runtime failures would also be made available. Many (Fortran) tests provide either a stop code, or some hopefully helpful diagnostic output on stdout intended for locating errors on platforms where one has no direct access to, or is less familiar with. Far better than a plain FAIL: gfortran.dg/value_9.f90 -O1 execution test * * * Thanks, Harald
From 3f97d10aa1ff5984d6fd657f246d3f251b254ff1 Mon Sep 17 00:00:00 2001 From: Harald Anlauf <anl...@gmx.de> Date: Sat, 24 Jun 2023 20:36:53 +0200 Subject: [PATCH] Fortran: ABI for scalar CHARACTER(LEN=1),VALUE dummy argument [PR110360] gcc/fortran/ChangeLog: PR fortran/110360 * trans-expr.cc (gfc_conv_procedure_call): Truncate constant string argument of length > 1 passed to scalar CHARACTER(1),VALUE dummy. --- gcc/fortran/trans-expr.cc | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc index c92fccd0be2..63e3cf9681e 100644 --- a/gcc/fortran/trans-expr.cc +++ b/gcc/fortran/trans-expr.cc @@ -6395,20 +6395,25 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym, /* ABI: actual arguments to CHARACTER(len=1),VALUE dummy arguments are actually passed by value. - The BIND(C) case is handled elsewhere. - TODO: truncate constant strings to length 1. */ + Constant strings are truncated to length 1. + The BIND(C) case is handled elsewhere. */ if (fsym->ts.type == BT_CHARACTER && !fsym->ts.is_c_interop && fsym->ts.u.cl->length->expr_type == EXPR_CONSTANT && fsym->ts.u.cl->length->ts.type == BT_INTEGER && (mpz_cmp_ui - (fsym->ts.u.cl->length->value.integer, 1) == 0) - && e->expr_type != EXPR_CONSTANT) + (fsym->ts.u.cl->length->value.integer, 1) == 0)) { - parmse.expr = gfc_string_to_single_character - (build_int_cst (gfc_charlen_type_node, 1), - parmse.expr, - e->ts.kind); + if (e->expr_type != EXPR_CONSTANT) + parmse.expr = gfc_string_to_single_character + (build_int_cst (gfc_charlen_type_node, 1), + parmse.expr, + e->ts.kind); + else if (e->value.character.length > 1) + { + e->value.character.length = 1; + gfc_conv_expr (&parmse, e); + } } if (fsym->attr.optional -- 2.35.3