[flang][driver] Fix how output filename is generated

[awarzynski]

Summary

Currently, flang -c file.f generates flang_unparsed_source_file_0.o.
This is incorrect. This patch:

• simplifies the logic around output filename generation, and
• makes sure that file.o is produced instead of e.g. flang_unparsed_source_file_0.o when using the -c flag

The output filename generation is moved to a dedicated function. I've
also made a few minor improvements, e.g. marked variables as local,
added comments, refined error messages.

[sscalpone]

Worked for me. Thanks!

[DavidSpickett]

I was about to complain to you after finding:

ERROR: unrecognised option format CMakeFiles/FM002.dir/FM002.f.o

In our bot logs. But you already fixed it! Now I'll have to find something else to complain about :).

I also saw some:

rm: cannot remove 'flang_unparsed_source_file_0.f90': No such file or directory

So this should go a long way toward clearing up the test suite on our flang bots.

[awarzynski]

@DavidSpickett, thanks for investigating this!

In D105546#2877217, @DavidSpickett wrote:

Now I'll have to find something else to complain about :).

@sscalpone has been doing a great job in this area :) See https://reviews.llvm.org/D105896.

flang/tools/f18/flang.in

 # Global variables to make the parsing of input arguments a bit easier
 INPUT_FILES=()
 OPTIONS=()
 OUTPUT_FILE=""
 MODULE_DIR=""
 INTRINSICS_MOD_DIR=""
 COMPILE_ONLY="False"
 PREPROCESS_ONLY="False"
-TEMP_OUTPUT="flang_temp_out_"
 PRINT_VERSION="False"
 
 # === parse_args ==============================================================
 #
 # Parse the input arguments passed to this script. Sets the global variables
 # declared at the top.
 #
 # INPUTS:
while [ "${1:-}" != "" ]; do
       # CASE 2: A regular file (either source or a library file)
       elif [[ -f "$1" ]]; then
         INPUT_FILES+=($1)
         shift
         continue
 
       else
         # CASE 3: Unsupported
-        echo "ERROR: unrecognised option format $1"
+        echo "ERROR: unrecognised option format: \`$1\`. Perhaps non-existent file?"
         exit 1
       fi
   done
 }
 
 # === categorise_files ========================================================
 #
 # Categorises input files into:
then status=$?
          exit $status
     fi
   done
 
   # Preprocess other sources using Flang
   for idx in "${!other_srcs[@]}"; do
     if ! $ext_fc -E "${opts[@]}" "${other_srcs[$idx]}" ${output_definition:+$output_definition}
     then status=$?
-         echo flang: in "$PWD", flang-new failed with exit status $status: "$wd/bin/flang-new" "${flang_options[@]}" "$@" >&2
+         echo flang: in "$PWD", flang-new failed with exit status $status: "$wd/bin/flang-new" "${opts[@]}" "$@" >&2
          exit $status
     fi
   done
 }
 
+# === get_relocatable_name ======================================================
+#
+# Generate a name for the output object file based on the source file, e.g.
+#   * file.f --> file.o
+#   * file.c --> file.o
+# If OUTPUT_FILE is defined, use that instead.
+#
+# INPUTS:
+#   $1 - input source file for which to generate the output name
+# =============================================================================
+get_relocatable_name() {
+  local -r src_file=$1
+
+  if [[ ! -z ${OUTPUT_FILE:+x} ]]; then
+    out_file="$OUTPUT_FILE"
+  else
+    current_ext=${src_file##*.}
+    new_ext="o"
+
+    out_file=$(basename "${src_file}" "$current_ext")${new_ext}
+  fi
+
+  echo "$out_file"
+}
+
 # === main ====================================================================
 # Main entry point for this script
 # =============================================================================
 main() {
   parse_args "$@"
 
   if [[ $PRINT_VERSION == "True" ]]; then
     echo "flang version @FLANG_VERSION@"
     exit 0
   fi
 
-  fortran_source_files=()
-  other_source_files=()
-  object_files=()
-  lib_files=()
+  local fortran_source_files=()
+  local other_source_files=()
+  local object_files=()
+  local lib_files=()
   categorise_files INPUT_FILES fortran_source_files other_source_files object_files lib_files
 
   if [[ $PREPROCESS_ONLY == "True" ]]; then
     preprocess fortran_source_files other_source_files OPTIONS
     exit 0
   fi
 
   # Options for the Flang driver.
   # NOTE: We need `-fc1` to make sure that the frontend driver rather than
   # compiler driver is used. We also need to make sure that that's the first
   # flag that the driver will see (otherwise it assumes compiler/toolchain
   # driver mode).`f18` will just ignore this flag when uparsing, so it's fine
   # to add it here unconditionally.
-  flang_options=("-fc1")
+  local flang_options=("-fc1")
   # Options for the external Fortran Compiler
-  ext_fc_options=()
+  local ext_fc_options=()
   categorise_opts OPTIONS flang_options ext_fc_options
 
   local -r wd=$(cd "$(dirname "$0")/.." && pwd)
 
   # STEP 1: Unparse
   local -r unparsed_file="flang_unparsed_source_file"
   flang_options+=("-module-suffix")
   flang_options+=(".f18.mod")
   flang_options+=("-fdebug-unparse")
   flang_options+=("-fno-analyzed-objects-for-unparse")
 
   [[ ! -z ${MODULE_DIR} ]] && flang_options+=("-module-dir ${MODULE_DIR}")
   [[ ! -z ${INTRINSICS_MOD_DIR} ]] && flang_options+=("-intrinsics-module-directory ${INTRINSICS_MOD_DIR}")
   for idx in "${!fortran_source_files[@]}"; do
     if ! "$wd/bin/@FLANG_DEFAULT_DRIVER@" "${flang_options[@]}" "${fortran_source_files[$idx]}" -o "${unparsed_file}_${idx}.f90"
     then status=$?
          echo flang: in "$PWD", @FLANG_DEFAULT_DRIVER@ failed with exit status $status: "$wd/bin/@FLANG_DEFAULT_DRIVER@" "${flang_options[@]}" "$@" >&2
          exit $status
     fi
   done
 
   # STEP 2: Compile Fortran Source Files
   readonly ext_fc="${F18_FC:-gfortran}"
   for idx in "${!fortran_source_files[@]}"; do
-    # Use the value of $OUTPUT_FILE for the output file iff `-c` was used.
-    if [[ ! -z ${OUTPUT_FILE:+x} ]] && [[ $COMPILE_ONLY == "True" ]]; then
-      output_definition="-o $OUTPUT_FILE"
-    elif [[ $COMPILE_ONLY == "False" ]]; then
-      output_definition="-o ${TEMP_OUTPUT}_${idx}"
-    fi
+    # We always have to specify the output name with `-o <out_obj_file>`. This
+    # is because we are using the unparsed rather than the original source file
+    # below. As a result, we cannot rely on the compiler-generated output name.
+    out_obj_file=$(get_relocatable_name "${fortran_source_files[$idx]}")
 
-    if ! $ext_fc -c "${ext_fc_options[@]}" "${unparsed_file}_${idx}.f90" ${output_definition:+$output_definition}
+    if ! $ext_fc "-c" "${ext_fc_options[@]}" "${unparsed_file}_${idx}.f90" "-o" "${out_obj_file}"
     then status=$?
       echo flang: in "$PWD", "$ext_fc" failed with exit status $status: "$ext_fc" "${ext_fc_options[@]}" "$@" >&2
          exit $status
     fi
-    object_files+=(${TEMP_OUTPUT}_${idx})
+    object_files+=(${out_obj_file})
   done
 
   # Delete the unparsed files
   for idx in "${!fortran_source_files[@]}"; do
     rm "${unparsed_file}_${idx}.f90"
   done
 
   # STEP 3: Compile Other Source Files
   for idx in "${!other_source_files[@]}"; do
-    # Use the value of $OUTPUT_FILE for the output file iff `-c` was used.
-    if [[ ! -z ${OUTPUT_FILE:+x} ]] && [[ $COMPILE_ONLY == "True" ]]; then
-      output_definition="-o $OUTPUT_FILE"
-    elif [[ $COMPILE_ONLY == "False" ]]; then
-      output_definition="-o ${TEMP_OUTPUT}_${idx}"
-    fi
+    # We always specify the output name with `-o <out_obj_file>`. The user
+    # might have used `-o`, but we never add it to $OPTIONS (or
+    # $ext_fc_options). Hence we need to use `get_relocatable_name`.
+    out_obj_file=$(get_relocatable_name "${other_source_files[$idx]}")
 
-    if ! $ext_fc -c "${ext_fc_options[@]}" "${other_source_files[${idx}]}" ${output_definition:+$output_definition}
+    if ! $ext_fc "-c" "${ext_fc_options[@]}" "${other_source_files[${idx}]}" "-o" "${out_obj_file}"
     then status=$?
       echo flang: in "$PWD", "$ext_fc" failed with exit status $status: "$ext_fc" "${ext_fc_options[@]}" "$@" >&2
          exit $status
     fi
-    object_files+=(${TEMP_OUTPUT}_${idx})
+    object_files+=(${out_obj_file})
   done
 
   # STEP 4: Link
   if [[ $COMPILE_ONLY == "True" ]]; then
     exit 0;
   fi
 
   if [[ ${#object_files[@]} -ge 1 ]]; then
     # If $OUTPUT_FILE was specified, use it for the output name.
     if [[ ! -z ${OUTPUT_FILE:+x} ]]; then
       output_definition="-o $OUTPUT_FILE"
     else
       output_definition=""
     fi
 
     if ! $ext_fc "${ext_fc_options[@]}" "${object_files[@]}" "${lib_files[@]}" ${output_definition:+$output_definition}
     then status=$?
          echo flang: in "$PWD", "$ext_fc" failed with exit status $status: "$ext_fc" "${ext_fc_options[@]}" "$@" >&2
          exit $status
     fi
   fi
 
   # Delete intermediate object files
   for idx in "${!fortran_source_files[@]}"; do
-    rm "${TEMP_OUTPUT}_${idx}"
+    rm "${object_files[$idx]}"
   done
 }
 
 main "${@}"