#! /bin/sh

: ${R_SRC_DIR=~/src/R}

args="--cache-file=config.cache \
--enable-R-shlib --enable-memory-profiling \
DEFS='-DUSE_TYPE_CHECKING_STRICT -D_FORTIFY_SOURCE=3' LIBnn=lib"
## DEFS='-DUSE_TYPE_CHECKING_STRICT' LIBnn=lib"
## --with-valgrind-instrumentation=1

## Compilers to use.
## Use configure defaults (gcc/g++/gfortran).
compilers=
flavor="-fg"
extra=false
blas=
## --with-blas=no is the current default ...
##   blas="--with-blas=no"

## <NOTE>
## If needed, the flavors could set their own user Makevars file via the
## environment variable R_MAKEVARS_USER.
## </NOTE>

while test -n "${1}"; do
  case "${1}" in
    -r)
      R_SRC_DIR=~/src/apps/R/r-release/R ;;
    -p)
      R_SRC_DIR=~/src/apps/R/r-patched/R ;;
    -d)
      R_SRC_DIR=~/src/apps/R/r-devel/R ;;
    -s)
      R_SRC_DIR="${2}"
      shift ;;
    -m)
      args="${args} --enable-maintainer-mode" ;;
    -x)
      extra=true ;;
    -bo)
      blas="--with-blas=-lopenblas --with-lapack=no" ;;
    -ba)
      blas="--with-blas='-lcblas -lf77blas -latlas' --with-lapack=no" ;;
    -bm)
      blas="--with-blas='-lmkl_gf_lp64 -lmkl_core -lmkl_sequential' --with-lapack" ;;
    -bi)
      blas="--with-blas=no --with-lapack=no" ;;
    -b)
      blas="--with-blas=yes --with-lapack=yes" ;;
    -v)
      args="${args} --with-valgrind-instrumentation=2 --with-system-valgrind-headers" ;;
    -f*)
      flavor="${1}" ;;
    *)
      args="${args} ${1}" ;;
  esac
  shift
done

## <FIXME>
## libdeflate
## Use new --with-libdeflate-compression=yes for r-devel: currently not
## done by default.
## ## Drop when we switch the default to yes.
## case "${R_SRC_DIR}" in
##   */src/apps/R/r-devel/R)
##     args="${args} --with-libdeflate-compression=yes" ;;
## esac
## </FIXME>

## <NOTE>
## One can use the undocumented R configure variable CXXSTD to specify
## the C++ standard for the *default* C++ compiler (and use CXX23STD etc
## for the specific ones if necessary).
## We provide CC_STD for specifying the C standard.

args="${args} ${blas}"

case "${flavor}" in    
  -fg*)
    ## flavor: gcc
    ## <NOTE>
    ## When primarily using clang for testing, configure with
    ## --disable-long-double so that we can emulate hardware with no
    ## excess fp precision results:
    ##   args="${args} --disable-long-double"
    ## </NOTE>
    v=`expr "${flavor}" : ".*/\\(.*\\)"`
    gcc_series_is_snap=false
    case "${v}" in 
      snap)
	gcc_series_is_snap=true ;;
    esac
    PREFIX=
    SUFFIX=
    if test "${gcc_series_is_snap}" = "true"; then
      PREFIX="/usr/lib/gcc-snapshot/bin/"
    elif test -n "${v}"; then
      SUFFIX="-${v}"
    fi
    ## C and C++ standards:
    ## See <https://gcc.gnu.org/onlinedocs/gcc/Standards.html>.
    ## As of 2024-11 defaults are as follows:
    ## * if no C language dialect options are given: -std=gnu17
    ## * if no C++ language dialect options are given, -std=gnu++17
    ## See also <https://gcc.gnu.org/projects/cxx-status.html>:
    ## * C++17 features are available since GCC 5. This mode is the
    ##   default in GCC 11. 
    ## * C++14 is the default in GCC 6.1 up until GCC 10 (including);
    ##   it can be explicitly selected with the -std=c++14 command-line
    ##   flag, or -std=gnu++14 to enable GNU extensions as well. 
    ## * C++98 is the default in GCC versions prior to 6.1; 
    ##   it can be explicitly selected with the -std=c++98 command-line
    ##   flag, or -std=gnu++98 to enable GNU extensions as well.
    if test "${extra}" = "true"; then
      CC_EXTRA="-fsanitize=address,undefined -fno-omit-frame-pointer"
      CXX_EXTRA="-fsanitize=address,undefined,bounds-strict -fno-omit-frame-pointer"
      FC_EXTRA="-fsanitize=address"
      ## As of 2015-09-07, compilation with ASAN/UBSAN fails on the
      ## #pragma omp parallel in /src/library/stats/src/distance.c:
      ## Hence, disable OpenMP for the time being.
      args="${args} --disable-openmp"
    else
      CC_EXTRA=
      CXX_EXTRA=
      FC_EXTRA=
    fi
    CC="${PREFIX}gcc${SUFFIX}"
    test -n "${CC_STD}" && CC="${CC} ${CC_STD}"
    test -n "${CC_EXTRA}" && CC="${CC} ${CC_EXTRA}"
    CXX="${PREFIX}g++${SUFFIX}"
    test -n "${CXX_EXTRA}" && CXX="${CXX} ${CXX_EXTRA}"
    FC="${PREFIX}gfortran${SUFFIX}"
    test -n "${FC_EXTRA}" && FC="${FC} ${FC_EXTRA}"
    OBJC="${PREFIX}gcc${SUFFIX}"
    OBJCXX="${PREFIX}gcc${SUFFIX}"
    compilers="CC=\"${CC}\" CXX=\"${CXX}\" OBJC=${OBJC} OBJCXX=${OBJCXX} FC=\"${FC}\" F77=\"${FC}\""
    if test "${gcc_series_is_snap}" = "true"; then
      compilers="${compilers} LDFLAGS=-L/usr/lib/gcc-snapshot/lib"
      ## compilers="${compilers} LDFLAGS=-Wl,-rpath,/usr/lib/gcc-snapshot/lib"
    fi
    if test "${extra}" = "true"; then
      compilers="${compilers} MAIN_LDFLAGS=\"-fsanitize=address,undefined\""
    fi
    ;;
  -fc*)
    ## flavor: clang
    ## Using '-stdlib=libc++' does not always work for packages linking
    ## against system libraries built against -lstdc++ (e.g., JAGS).
    ## <FIXME>
    ## As of 2024-01, Debian testing with the LLVM 17 compilers has OMP
    ## runtime problems, eventually giving errors like
    ##   OMP: Error #13: Assertion failure at kmp_runtime.cpp(6891).
    ## So for the time being, disable OpenMP.
    args="${args} --disable-openmp"
    ## </FIXME>
    vc=`expr "${flavor}" : "[^/]*/\\([^/]*\\)\\(/.*\\)\\?"`
    vg=`expr "${flavor}" : "[^/]*/[^/]*/\\(.*\\)"`
    test -n "${vc}" && vc="-${vc}"
    test -n "${vg}" && vg="-${vg}"
    if test "${extra}" = "true"; then
      CC_EXTRA="-fsanitize=address,undefined -fno-sanitize=float-divide-by-zero -fno-sanitize=alignment  -fno-omit-frame-pointer"
      CXX_EXTRA="-fsanitize=address,undefined -fno-sanitize=float-divide-by-zero -fno-sanitize=alignment -fno-omit-frame-pointer -frtti"
    else
      CC_EXTRA=
      CXX_EXTRA=
    fi
    CC="clang${vc}"
    test -n "${CC_STD}" && CC="${CC} ${CC_STD}"
    test -n "${CC_EXTRA}" && CC="${CC} ${CC_EXTRA}"
    CXX="clang++${vc}"
    test -n "${CXX_STDLIB}" && CXX="${CXX} -stdlib=${CXX_STDLIB}"
    test -n "${CXX_EXTRA}" && CXX="${CXX} ${CXX_EXTRA}"    
    ## <FIXME>
    ## As of 2014-09-10, we had
    ##   Clang can compile Objective-C and Objective-C++, but needs a
    ##   runtime and the corresponding headers (e.g., 'objc/Object.h'):
    ##   on Debian/Ubuntu, the latter are currently only available in
    ##   the respective GCC version-specific header directories (e.g.,
    ##   '/usr/lib/gcc/x86_64-linux-gnu/4.9/include'), and hence not
    ##   really usable for Clang.
    ##   One could try using the GNUstep Objective-C runtime and headers
    ##   (libobjc2 available from http://download.gna.org/gnustep/) but
    ##   this is not available for Debian/Ubuntu.
    ##   Hence, use GCC for Objective-C and Objective-C++.
    ##   What a nuisance ...
    ## As of 2023-11, apparently clang can be configured ok to use as
    ## the Objective C compiler.  Objective C++ works for neither gcc
    ## nor clang as configure fails to find the Foundation/Foundation.h
    ## header ...
    ## </FIXME>
    OBJC="clang${vc}"
    OBJCXX="clang${vc}"
    compilers="CC=\"${CC}\" CXX=\"${CXX}\" OBJC=${OBJC} OBJCXX=${OBJCXX}"
    if test "${extra}" = "true"; then
      compilers="${compilers} MAIN_LD=\"clang++${vc} -fsanitize=undefined,address\""
    fi
    ## Note that the LLVM Fortran front does not work for versions below
    ## 17.
    if test -n "${vc}" && test -z "${vg}"; then
      FC="flang-new${vc}"
    else
      FC="gfortran${vg}"
    fi
    compilers="${compilers} FC=${FC} F77=${FC}"
    ;;
esac

eval ${R_SRC_DIR}/configure ${args} ${compilers}