COMP: stricter handling of openmp vs no-openmp

- give precedence to ~openmp (-no-openmp) over +openmp (-openmp)
  in the general rules and in the Makefile. This makes it robuster
  when specifying +openmp in general, but ~openmp for specific build
  components.

- disable openmp for OSspecific and Pstream components.
  Neither should contain any openmp code anyhow.

  Additionally, since OSspecific is generally built as a static
  object, it can become problematic (eg, with AMD ROCm) if the
  compiler generates information that openmp is required but then uses
  static linkage.

src/OSspecific/MSwindows/Allwmake

@@ -19,6 +19,7 @@ fi
 unset COMP_FLAGS LINK_FLAGS
 
 # Make object (non-shared by default)
-wmake $targetType
+# Never want/need openmp, especially for static objects
+wmake -no-openmp $targetType
 
 #------------------------------------------------------------------------------

src/OSspecific/POSIX/Allwmake

@@ -14,6 +14,7 @@ then
 fi
 
 # Make object (non-shared by default)
-wmake $targetType
+# Never want/need openmp, especially for static objects
+wmake -no-openmp $targetType
 
 #------------------------------------------------------------------------------

src/Pstream/Allwmake

@@ -3,9 +3,10 @@ cd "${0%/*}" || exit                                # Run from this directory
 . ${WM_PROJECT_DIR:?}/wmake/scripts/AllwmakeParseArguments
 
 #------------------------------------------------------------------------------
+# Never need/want openmp for MPI interfaces, or for static linkage
 
-echo "wmake $targetType dummy (mpi=$WM_MPLIB)"
+echo "wmake -no-openmp $targetType${targetType:+ }dummy (mpi=$WM_MPLIB)"
-wmake $targetType dummy
+wmake -no-openmp $targetType dummy
 
 ./Allwmake-mpi $targetType $*
 

src/Pstream/Allwmake-mpi

@@ -7,6 +7,7 @@ cd "${0%/*}" || exit                                # Run from this directory
 # Environment
 #   - FOAM_MPI_LIBBIN (optional: defaults to FOAM_LIBBIN/FOAM_MPI)
 
-wmakeLibMpi mpi
+# Never need/want openmp for MPI interfaces
+wmakeLibMpi -no-openmp mpi
 
 #------------------------------------------------------------------------------

src/parallel/decompose/Allwmake-mpi

@@ -15,7 +15,8 @@ if have_scotch
 then
     if have_ptscotch
     then
-        wmakeLibMpi ptscotchDecomp "scotch=$SCOTCH_VERSION"
+        # Never need/want openmp for MPI interfaces
+        wmakeLibMpi -no-openmp ptscotchDecomp "scotch=$SCOTCH_VERSION"
     fi
 fi
 

wmake/makefiles/general

@@ -6,7 +6,7 @@
 #    \\/     M anipulation  |
 #------------------------------------------------------------------------------
 #     Copyright (C) 2011-2016 OpenFOAM Foundation
-#     Copyright (C) 2019-2022 OpenCFD Ltd.
+#     Copyright (C) 2019-2023 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
 #     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
@@ -19,7 +19,7 @@
 #
 # Embedded Control Parameters
 #
-#   WM_COMPILE_CONTROL (+openmp)
+#   WM_COMPILE_CONTROL (+openmp | ~openmp)
 #   WM_COMPILE_CONTROL (~openfoam)
 #   WM_OSTYPE (windows)
 #
@@ -62,9 +62,13 @@ SYS_INC         =
 SYS_LIBS        =
 
 # Add linkage for openmp into the system libraries
+# - if enabled (+openmp) and not disabled (~openmp).
+# - disable has higher precedence
+ifeq  (,$(findstring ~openmp,$(WM_COMPILE_CONTROL)))
 ifneq (,$(findstring +openmp,$(WM_COMPILE_CONTROL)))
 SYS_LIBS        = $(LINK_OPENMP)
 endif
+endif
 
 # These are set by Make/options
 EXE_INC         =

wmake/rules/General/general

@@ -52,10 +52,14 @@ sinclude $(RULES)/general
 sinclude $(RULES)/c++
 endif
 
-# Add compile flags for openmp
+# Compile flags for openmp
+# - if enabled (+openmp) and not disabled (~openmp).
+# - disable has higher precedence
+ifeq  (,$(findstring ~openmp,$(WM_COMPILE_CONTROL)))
 ifneq (,$(findstring +openmp,$(WM_COMPILE_CONTROL)))
     c++FLAGS  += $(COMP_OPENMP)
 endif
+endif
 
 include $(GENERAL_RULES)/transform
 

wmake/scripts/AllwmakeParseArguments

@@ -27,6 +27,7 @@
 #
 # Parsed options (wmake)
 #     -debug | -debug-O[g0123]
+#     -openmp | -no-openmp
 #     -strict
 #     -q | -queue
 #     -build-root=...
@@ -88,7 +89,7 @@ USAGE
 #------------------------------------------------------------------------------
 
 unset wmakeOpt_frontend wmakeOpt_nonRecursive
-unset wmakeOpt_debug wmakeOpt_log wmakeOpt_strict wmakeOpt_queue
+unset wmakeOpt_debug wmakeOpt_log wmakeOpt_openmp wmakeOpt_strict wmakeOpt_queue
 
 for arg in "$@"
 do
@@ -184,6 +185,11 @@ do
         continue    # Argument handled, remove it
         ;;
 
+    -openmp | -no-openmp)
+        wmakeOpt_openmp="$arg"
+        continue    # Argument handled, remove it
+        ;;
+
     -q | -queue)
         wmakeOpt_queue="-queue"
         continue    # Argument handled, remove it
@@ -240,7 +246,7 @@ fi
 #------------------------------------------------------------------------------
 
 unset wmakeOpt_frontend wmakeOpt_nonRecursive
-unset wmakeOpt_debug wmakeOpt_log wmakeOpt_strict wmakeOpt_queue
+unset wmakeOpt_debug wmakeOpt_log wmakeOpt_openmp wmakeOpt_strict wmakeOpt_queue
 unset -f usage
 
 

wmake/scripts/wmakeFunctions

@@ -6,7 +6,7 @@
 #    \\/     M anipulation  |
 #------------------------------------------------------------------------------
 #     Copyright (C) 2015-2016 OpenFOAM Foundation
-#     Copyright (C) 2018-2021 OpenCFD Ltd.
+#     Copyright (C) 2018-2023 OpenCFD Ltd.
 #------------------------------------------------------------------------------
 # License
 #     This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
@@ -348,19 +348,43 @@ sameDependency()
 
 
 # Build a mpi-versioned library (targetType)
-# - use sentinel file(s) to handle paraview version changes
+# compile into MPI-qualified directory
-# compile into qualified directory
 # use sentinel file(s) to handle version changes
 # 1 - libName
 # 2... build/configure information
 #
 # Global variables used:
 # - WM_OPTIONS, WM_MPLIB, FOAM_MPI
+# - targetType
 #
 # Requires that WM_MPLIB contain an "MPI" string
+#
+# Has very simple option handling (bool options only!) that allow
+# things like "wmakeLibMpi -debug -no-openmp" etc.
+#
 wmakeLibMpi()
 {
-    local libName="$1"
+    local libName
+    local wmakeCmd="wmake"
+
+    # Very simple option handling (bool options only!)
+    while [ "$#" -gt 0 ]
+    do
+        case "$1" in
+        (- | --)    # Stop option parsing
+            shift
+            break
+            ;;
+        (-*)        # Any bool option
+            wmakeCmd="$wmakeCmd $1"
+            ;;
+        (*)
+            break   # Done
+            ;;
+        esac
+        shift
+    done
+    libName="$1"
     shift
 
     case "$WM_MPLIB" in (*MPI* | *mpi*)
@@ -374,8 +398,8 @@ wmakeLibMpi()
         sentinel=$(sameDependency "$libName" "MPLIB=$WM_MPLIB" "MPI=$FOAM_MPI" $@) || \
             wclean "$libName"
 
-        echo "wmake $targetType $libName (mpi=$WM_MPLIB:$FOAM_MPI)"
+        echo "$wmakeCmd $targetType${targetType:+ }(mpi=$WM_MPLIB:$FOAM_MPI)"
-        wmake $targetType "$libName" && \
+        $wmakeCmd $targetType "$libName" && \
         storeDependency "$sentinel" "MPLIB=$WM_MPLIB" "MPI=$FOAM_MPI" $@
     )
     ;;