On Thu, Apr 16, 2026 at 10:18 AM Christopher Albert <[email protected]> wrote: > > The Fortran preprocessor has never defined target-specific macros such as > __linux__, __unix__, __ELF__, __x86_64__, or __amd64__ that the C > preprocessor provides. This was caused by the TARGET_OS_CPP_BUILTINS, > TARGET_OBJFMT_CPP_BUILTINS, and TARGET_CPU_CPP_BUILTINS hooks being > disabled since 2008 (marked as "Pandora's Box") because several target > config headers use C-family-only functions. > > Fix by providing Fortran-compatible local helpers for > builtin_define_std, builtin_define_with_value, and > builtin_define_with_int_value (which in the C frontend live in > c-family/c-cppbuiltin.cc and use the C-family-only globals parse_in > and flag_iso), plus wrapper macros for c_dialect_cxx, flag_iso, and > other C-family identifiers referenced by target config headers. This > allows TARGET_OS_CPP_BUILTINS and TARGET_OBJFMT_CPP_BUILTINS to > execute in the Fortran frontend. > > Unlike the C frontend default (flag_iso=0, GNU extensions mode), the > Fortran wrapper sets flag_iso=1 to suppress user-namespace macros like > bare "unix" and "linux" that would conflict with Fortran identifiers. > Only the reserved-namespace forms (__unix__, __linux__, etc.) are > defined. Fortran has no -std=cNN equivalent to control this, so the > conservative choice avoids silent identifier replacement. > > For TARGET_CPU_CPP_BUILTINS, which on most architectures expands to a > function in a C-family-only object file (e.g., ix86_target_macros in > i386-c.cc), provide an x86 implementation directly in fortran/cpp.cc > that covers architecture identification and float-size macros. > ISA feature macros (__SSE__, __AVX__, etc.) are not included; if > needed, they could be factored out of i386-c.cc into a shared object. > > Remove the dead __attribute__((target(...))) block from > gfortran.dg/gomp/declare-variant-10.f90: it was guarded by > #if defined(__x86_64__) which was previously always false because > gfortran never defined these macros, and gfortran does not support > C-style __attribute__ syntax. > > Co-authored-by: Kai Tietz <[email protected]> > > PR fortran/42954 > > gcc/fortran/ChangeLog: > > * cpp.cc (gfc_builtin_define_std): New helper mirroring > builtin_define_std from c-family/c-cppbuiltin.cc. > (gfc_builtin_define_with_value): New helper mirroring > builtin_define_with_value from c-family/c-cppbuiltin.cc. > (gfc_define_ix86_target_macros): New function providing x86 CPU > identification macros for the Fortran preprocessor. > (gfc_darwin_cpp_builtins): New function providing Darwin platform > macros. > (cpp_define_builtins): Remove Pandora's Box FIXME. Add wrapper > macros for C-family functions and variables used in target config > headers. Set flag_iso=1 to suppress bare-name macros. Enable > TARGET_OS_CPP_BUILTINS and TARGET_OBJFMT_CPP_BUILTINS. Call > gfc_define_ix86_target_macros on x86 targets.
THIS is all wrong and causes too many issues. Please revert this. > > gcc/testsuite/ChangeLog: > > * gfortran.dg/gomp/declare-variant-10.f90: Remove dead > __attribute__((target)) block that is now exposed by newly > defined target macros. > * gfortran.dg/pr42954-linux.f90: New test. > * gfortran.dg/pr42954-x86.f90: New test. > > Signed-off-by: Christopher Albert <[email protected]> > --- > gcc/fortran/cpp.cc | 178 ++++++++++++++++-- > .../gfortran.dg/gomp/declare-variant-10.f90 | 3 - > gcc/testsuite/gfortran.dg/pr42954-linux.f90 | 24 +++ > gcc/testsuite/gfortran.dg/pr42954-x86.f90 | 10 + > 4 files changed, 194 insertions(+), 21 deletions(-) > create mode 100644 gcc/testsuite/gfortran.dg/pr42954-linux.f90 > create mode 100644 gcc/testsuite/gfortran.dg/pr42954-x86.f90 > > diff --git a/gcc/fortran/cpp.cc b/gcc/fortran/cpp.cc > index 6b5f136e4f3..ada1bc1a211 100644 > --- a/gcc/fortran/cpp.cc > +++ b/gcc/fortran/cpp.cc > @@ -157,6 +157,126 @@ void pp_dir_change (cpp_reader *, const char *); > static int dump_macro (cpp_reader *, cpp_hashnode *, void *); > static void dump_queued_macros (cpp_reader *); > > +/* Fortran-local helpers that mirror builtin_define_std, > + builtin_define_with_value, and builtin_define_with_int_value from > + c-family/c-cppbuiltin.cc. Those functions use the C-family-only > + globals parse_in and flag_iso, so they cannot be called directly > + from the Fortran frontend. */ > + > +/* Given "unix", define __unix, __unix__, and (if DEFINE_USER) unix. */ > + > +static void > +gfc_builtin_define_std (cpp_reader *pfile, const char *macro, > + bool define_user) > +{ > + size_t len = strlen (macro); > + char *buff = (char *) alloca (len + 5); > + char *p = buff + 2; > + char *q = p + len; > + > + memcpy (p, macro, len + 1); > + if (!(*p == '_' && (p[1] == '_' || ISUPPER (p[1])))) > + { > + if (*p != '_') > + *--p = '_'; > + if (p[1] != '_') > + *--p = '_'; > + } > + cpp_define (pfile, p); > + > + if (p != buff + 2) > + { > + if (q[-1] != '_') > + *q++ = '_'; > + if (q[-2] != '_') > + *q++ = '_'; > + *q = '\0'; > + cpp_define (pfile, p); > + if (define_user) > + cpp_define (pfile, macro); > + } > +} > + > +/* Define MACRO to EXPANSION; if IS_STR, quote the expansion. */ > + > +static void > +gfc_builtin_define_with_value (cpp_reader *pfile, const char *macro, > + const char *expansion, int is_str) > +{ > + size_t mlen = strlen (macro); > + size_t elen = strlen (expansion); > + char *buf = (char *) alloca (mlen + elen + 4); > + if (is_str) > + sprintf (buf, "%s=\"%s\"", macro, expansion); > + else > + sprintf (buf, "%s=%s", macro, expansion); > + cpp_define (pfile, buf); > +} > + > +/* Provide x86 CPU identification macros for the Fortran preprocessor. > + TARGET_CPU_CPP_BUILTINS() cannot be called directly because it expands > + to ix86_target_macros() in i386-c.cc, which is only linked into > + C-family frontends. This covers architecture identification and > + float-size macros. ISA feature macros (__SSE__, __AVX__, etc.) and > + arch/tune macros (__znver4__, __skylake__, etc.) from > + ix86_target_macros_internal() are not included; if needed, they could > + be factored out of i386-c.cc into a shared object. */ > + > +#ifdef TARGET_80387 Please DON'T add target defines directly to the front-end. Please instead use a config file from the target instead. Like what is done for d, rust, etc. front-ends. Each target should have their a source file which does the cpp_ instead of inlining it in the fortran front-end. Thanks, Andrea > +static void > +gfc_define_ix86_target_macros (cpp_reader *pfile) > +{ > + if (TARGET_64BIT) > + { > + cpp_assert (pfile, "cpu=x86_64"); > + cpp_assert (pfile, "machine=x86_64"); > + cpp_define (pfile, "__amd64"); > + cpp_define (pfile, "__amd64__"); > + cpp_define (pfile, "__x86_64"); > + cpp_define (pfile, "__x86_64__"); > + if (TARGET_X32) > + { > + cpp_define (pfile, "_ILP32"); > + cpp_define (pfile, "__ILP32__"); > + } > + } > + else > + { > + cpp_assert (pfile, "cpu=i386"); > + cpp_assert (pfile, "machine=i386"); > + gfc_builtin_define_std (pfile, "i386", false); > + cpp_define (pfile, "_ILP32"); > + cpp_define (pfile, "__ILP32__"); > + } > + > + if (!TARGET_80387) > + cpp_define (pfile, "_SOFT_FLOAT"); > + > + if (TARGET_LONG_DOUBLE_64) > + cpp_define (pfile, "__LONG_DOUBLE_64__"); > + > + if (TARGET_LONG_DOUBLE_128) > + cpp_define (pfile, "__LONG_DOUBLE_128__"); > + > + cpp_define_formatted (pfile, "__SIZEOF_FLOAT80__=%d", > + GET_MODE_SIZE (XFmode)); > + cpp_define (pfile, "__SIZEOF_FLOAT128__=16"); > +} > +#endif > + > +/* Provide essential Darwin platform macros for the Fortran preprocessor. > + The full darwin_cpp_builtins() in darwin-c.cc also defines > + __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ and > + __CONSTANT_CFSTRINGS__, but those depend on functions only linked > + into C-family frontends. */ > + > +static void ATTRIBUTE_UNUSED > +gfc_darwin_cpp_builtins (cpp_reader *pfile) > +{ > + cpp_define (pfile, "__MACH__"); > + cpp_define (pfile, "__APPLE__"); > + gfc_builtin_define_with_value (pfile, "__APPLE_CC__", "1", false); > +} > > static void > cpp_define_builtins (cpp_reader *pfile) > @@ -177,33 +297,55 @@ cpp_define_builtins (cpp_reader *pfile) > if (flag_openmp) > cpp_define (pfile, "_OPENMP=202111"); > > - /* The defines below are necessary for the TARGET_* macros. > - > - FIXME: Note that builtin_define_std() actually is a function > - in c-cppbuiltin.cc which uses flags undefined for Fortran. > - Let's skip this for now. If needed, one needs to look into it > - once more. */ > + /* Wrapper macros for C-family identifiers used in target config > + headers. These allow TARGET_OS_CPP_BUILTINS and > + TARGET_OBJFMT_CPP_BUILTINS to compile in the Fortran frontend. */ > > # define builtin_define(TXT) cpp_define (pfile, TXT) > -# define builtin_define_std(TXT) > +# define builtin_define_std(TXT) gfc_builtin_define_std (pfile, TXT, > !flag_iso) > +# define builtin_define_with_value(MACRO, EXPANSION, IS_STR) \ > + gfc_builtin_define_with_value (pfile, MACRO, EXPANSION, IS_STR) > +# define builtin_define_with_int_value(MACRO, VALUE) \ > + cpp_define_formatted (pfile, "%s=" HOST_WIDE_INT_PRINT_DEC, \ > + MACRO, (HOST_WIDE_INT) (VALUE)) > # define builtin_assert(TXT) cpp_assert (pfile, TXT) > +# define c_dialect_cxx() 0 > +# define c_dialect_objc() 0 > +# define preprocessing_asm_p() 0 > +# define preprocessing_trad_p() 0 > + /* Fortran has no -std=cNN flag to control this. Set to 1 (ISO mode) > + so that builtin_define_std() only defines reserved-namespace macros > + like __unix__ and __linux__, not bare "unix" or "linux" which are > + valid Fortran identifiers and would cause silent replacement. */ > +# define flag_iso 1 > +# define flag_isoc94 0 > +# define flag_isoc99 0 > +# define flag_isoc11 0 > +# define flag_isoc23 0 > +# define darwin_cpp_builtins(PFILE) gfc_darwin_cpp_builtins (PFILE) > > - /* FIXME: Pandora's Box > - Using the macros below results in multiple breakages: > - - mingw will fail to compile this file as dependent macros > - assume to be used in c-cppbuiltin.cc only. Further, they use > - flags only valid/defined in C (same as noted above). > - [config/i386/mingw32.h, config/i386/cygming.h] > - - other platforms (not as popular) break similarly > - [grep for 'builtin_define_with_int_value' in gcc/config/] > - > - TARGET_CPU_CPP_BUILTINS (); > TARGET_OS_CPP_BUILTINS (); > - TARGET_OBJFMT_CPP_BUILTINS (); */ > + TARGET_OBJFMT_CPP_BUILTINS (); > + > +#ifdef TARGET_80387 > + gfc_define_ix86_target_macros (pfile); > +#endif > > #undef builtin_define > #undef builtin_define_std > +#undef builtin_define_with_value > +#undef builtin_define_with_int_value > #undef builtin_assert > +#undef c_dialect_cxx > +#undef c_dialect_objc > +#undef preprocessing_asm_p > +#undef preprocessing_trad_p > +#undef flag_iso > +#undef flag_isoc94 > +#undef flag_isoc99 > +#undef flag_isoc11 > +#undef flag_isoc23 > +#undef darwin_cpp_builtins > } > > bool > diff --git a/gcc/testsuite/gfortran.dg/gomp/declare-variant-10.f90 > b/gcc/testsuite/gfortran.dg/gomp/declare-variant-10.f90 > index 0e0ab518010..115195e1194 100644 > --- a/gcc/testsuite/gfortran.dg/gomp/declare-variant-10.f90 > +++ b/gcc/testsuite/gfortran.dg/gomp/declare-variant-10.f90 > @@ -64,9 +64,6 @@ contains > call f18 () ! { dg-final { scan-tree-dump-times "f18 \\\(\\\);" > 1 "gimple" } } */ > end subroutine > > -#if defined(__i386__) || defined(__x86_64__) > - __attribute__((target ("avx512f,avx512bw"))) > -#endif > subroutine test2 () > !$omp target > call f04 () ! { dg-final { scan-tree-dump-times "f03 \\\(\\\);" 1 > "gimple" { target { { i?86-*-* x86_64-*-* } && { ! ilp32 } } } } } > diff --git a/gcc/testsuite/gfortran.dg/pr42954-linux.f90 > b/gcc/testsuite/gfortran.dg/pr42954-linux.f90 > new file mode 100644 > index 00000000000..bd5efe7a237 > --- /dev/null > +++ b/gcc/testsuite/gfortran.dg/pr42954-linux.f90 > @@ -0,0 +1,24 @@ > +! { dg-do preprocess { target *-*-linux* } } > +! { dg-options "-cpp" } > +! > +! PR fortran/42954 - target macros missing in gfortran -cpp > + > +#ifndef __linux__ > +# error __linux__ not defined > +#endif > + > +#ifndef __linux > +# error __linux not defined > +#endif > + > +#ifndef __unix__ > +# error __unix__ not defined > +#endif > + > +#ifndef __unix > +# error __unix not defined > +#endif > + > +#ifndef __ELF__ > +# error __ELF__ not defined > +#endif > diff --git a/gcc/testsuite/gfortran.dg/pr42954-x86.f90 > b/gcc/testsuite/gfortran.dg/pr42954-x86.f90 > new file mode 100644 > index 00000000000..0a3b7eac8a2 > --- /dev/null > +++ b/gcc/testsuite/gfortran.dg/pr42954-x86.f90 > @@ -0,0 +1,10 @@ > +! { dg-do preprocess { target { i?86-*-* x86_64-*-* } } } > +! { dg-options "-cpp" } > +! > +! PR fortran/42954 - target macros missing in gfortran -cpp > + > +#if !defined(__i386__) && !defined(__i386) \ > + && !defined(__x86_64__) && !defined(__x86_64) \ > + && !defined(__amd64__) && !defined(__amd64) > +# error x86 target macros not defined > +#endif > -- > 2.53.0 >
