clang, cc-wrapper: make wrapper flang-aware

Build on the initial LLVM Flang wrapper work by exposing the needed clang passthru and teaching cc-wrapper about flang-specific flag handling.

Co-authored-by: stove <stove@rivosinc.com>
Co-authored-by: acture <acture@gmail.com>
Co-authored-by: Emily <hello@emily.moe>
Co-authored-by: Philip Taron <philip.taron@gmail.com>

pkgs/build-support/cc-wrapper/add-clang-cc-cflags-before.sh

@@ -36,6 +36,6 @@ elif [[ $0 != *cpp ]]; then
     fi
 fi
 
-if [[ "@darwinMinVersion@" ]]; then
+if [[ "@darwinMinVersion@" ]] && [ "@isFlang@" != 1 ]; then
     extraBefore+=(-Werror=unguarded-availability)
 fi

pkgs/build-support/cc-wrapper/add-flags.sh

@@ -11,6 +11,8 @@ var_templates_list=(
     NIX_CXXSTDLIB_COMPILE
     NIX_CXXSTDLIB_LINK
     NIX_GNATFLAGS_COMPILE
+    NIX_FFLAGS_COMPILE
+    NIX_FFLAGS_COMPILE_BEFORE
 )
 var_templates_bool=(
     NIX_ENFORCE_NO_NATIVE

pkgs/build-support/cc-wrapper/cc-wrapper.sh

@@ -44,7 +44,7 @@ while (( "$n" < "$nParams" )); do
 
     case "$p" in
         -[cSEM] | -MM) dontLink=1 ;;
-        -cc1) cc1=1 ;;
+        -cc1 | -fc1 ) cc1=1 ;;
         -nostdinc) cInclude=0 cxxInclude=0 ;;
         -nostdinc++) cxxInclude=0 ;;
         -nostdlib) cxxLibrary=0 ;;
@@ -185,9 +185,19 @@ fi
 
 source @out@/nix-support/add-hardening.sh
 
-# Add the flags for the C compiler proper.
-extraAfter=(${hardeningCFlagsAfter[@]+"${hardeningCFlagsAfter[@]}"} $NIX_CFLAGS_COMPILE_@suffixSalt@)
-extraBefore=(${hardeningCFlagsBefore[@]+"${hardeningCFlagsBefore[@]}"} $NIX_CFLAGS_COMPILE_BEFORE_@suffixSalt@)
+# Add the flags for the compiler proper. Flang reads its user-supplied
+# flags from the Fortran-specific NIX_FFLAGS_COMPILE channel so that
+# C-only flags injected by setup hooks (e.g. -frandom-seed= from
+# reproducible-builds.sh, which Flang does not accept) never reach the
+# Fortran driver. This mirrors the NIX_GNATFLAGS_COMPILE channel that
+# the Ada/GNAT wrapper uses for the same reason.
+if [ "@isFlang@" = 1 ]; then
+    extraAfter=(${hardeningCFlagsAfter[@]+"${hardeningCFlagsAfter[@]}"} $NIX_FFLAGS_COMPILE_@suffixSalt@)
+    extraBefore=(${hardeningCFlagsBefore[@]+"${hardeningCFlagsBefore[@]}"} $NIX_FFLAGS_COMPILE_BEFORE_@suffixSalt@)
+else
+    extraAfter=(${hardeningCFlagsAfter[@]+"${hardeningCFlagsAfter[@]}"} $NIX_CFLAGS_COMPILE_@suffixSalt@)
+    extraBefore=(${hardeningCFlagsBefore[@]+"${hardeningCFlagsBefore[@]}"} $NIX_CFLAGS_COMPILE_BEFORE_@suffixSalt@)
+fi
 
 if [ "$dontLink" != 1 ]; then
     linkType=$(checkLinkType $NIX_LDFLAGS_BEFORE_@suffixSalt@ "${params[@]}" ${NIX_CFLAGS_LINK_@suffixSalt@:-} $NIX_LDFLAGS_@suffixSalt@)

pkgs/build-support/cc-wrapper/default.nix

@@ -26,6 +26,7 @@
   nixSupport ? { },
   isGNU ? false,
   isClang ? cc.isClang or false,
+  isFlang ? cc.isFlang or false,
   isZig ? cc.isZig or false,
   isArocc ? cc.isArocc or false,
   isCcache ? cc.isCcache or false,
@@ -385,7 +386,9 @@ let
   #
   # TODO: Drop `mangle-NIX_STORE-in-__FILE__.patch` from GCC and make
   # this unconditional once the upstream bug is fixed.
-  useMacroPrefixMap = !isGNU;
+  useMacroPrefixMap = !isGNU && !isFlang;
+  systemIncludeFlag = if isFlang || isArocc then "-I" else "-idirafter";
+  fortifyIncludeFlag = if isFlang then "-I" else "-isystem";
 in
 
 assert includeFortifyHeaders' -> fortify-headers != null;
@@ -573,10 +576,18 @@ stdenvNoCC.mkDerivation {
   ''
 
   + optionalString cc.langFortran or false ''
-    wrap ${targetPrefix}gfortran $wrapper $ccPath/${targetPrefix}gfortran
-    ln -sv ${targetPrefix}gfortran $out/bin/${targetPrefix}g77
-    ln -sv ${targetPrefix}gfortran $out/bin/${targetPrefix}f77
-    export named_fc=${targetPrefix}gfortran
+    if [ -e $ccPath/${targetPrefix}gfortran ]; then
+      wrap ${targetPrefix}gfortran $wrapper $ccPath/${targetPrefix}gfortran
+      ln -sv ${targetPrefix}gfortran $out/bin/${targetPrefix}g77
+      ln -sv ${targetPrefix}gfortran $out/bin/${targetPrefix}f77
+      export named_fc=${targetPrefix}gfortran
+    elif [ -e $ccPath/${targetPrefix}flang ]; then
+      wrap ${targetPrefix}flang $wrapper $ccPath/${targetPrefix}flang
+      export named_fc=${targetPrefix}flang
+    elif [ -e $ccPath/flang ]; then
+      wrap ${targetPrefix}flang $wrapper $ccPath/flang
+      export named_fc=${targetPrefix}flang
+    fi
   ''
 
   + optionalString cc.langGo or false ''
@@ -712,9 +723,7 @@ stdenvNoCC.mkDerivation {
         echo "-B${libc_lib}${libc.libdir or "/lib/"}" >> $out/nix-support/libc-crt1-cflags
       ''
       + ''
-        include "-${
-          if isArocc then "I" else "idirafter"
-        }" "${libc_dev}${libc.incdir or "/include"}" >> $out/nix-support/libc-cflags
+        include "${systemIncludeFlag}" "${libc_dev}${libc.incdir or "/include"}" >> $out/nix-support/libc-cflags
       ''
       + optionalString isGNU ''
         for dir in "${cc}"/lib/gcc/*/*/include-fixed; do
@@ -722,9 +731,9 @@ stdenvNoCC.mkDerivation {
         done
       ''
       + optionalString (libc.w32api or null != null) ''
-        echo '-idirafter ${lib.getDev libc.w32api}${
+        include "${systemIncludeFlag}" "${lib.getDev libc.w32api}${
           libc.incdir or "/include/w32api"
-        }' >> $out/nix-support/libc-cflags
+        }" >> $out/nix-support/libc-cflags
       ''
       + ''
 
@@ -739,7 +748,7 @@ stdenvNoCC.mkDerivation {
       # like option that forces the libc headers before all -idirafter,
       # hence -isystem here.
       + optionalString includeFortifyHeaders' ''
-        include -isystem "${fortify-headers}/include" >> $out/nix-support/libc-cflags
+        include "${fortifyIncludeFlag}" "${fortify-headers}/include" >> $out/nix-support/libc-cflags
       ''
     )
 
@@ -760,7 +769,7 @@ stdenvNoCC.mkDerivation {
     # already knows how to find its own libstdc++, and adding
     # additional -isystem flags will confuse gfortran (see
     # https://github.com/NixOS/nixpkgs/pull/209870#issuecomment-1500550903)
-    + optionalString (libcxx == null && isClang && (useGccForLibs && gccForLibs.langCC or false)) ''
+    + optionalString (libcxx == null && isClang && useGccForLibs && (cc.langCC or false)) ''
       for dir in ${gccForLibs}/include/c++/*; do
         include -cxx-isystem "$dir" >> $out/nix-support/libcxx-cxxflags
       done
@@ -827,6 +836,7 @@ stdenvNoCC.mkDerivation {
       optionalString
         (
           (cc.isClang or false)
+          && !isFlang
           && !(cc.isROCm or false)
           && !targetPlatform.isDarwin
           && !targetPlatform.isAndroid
@@ -861,7 +871,8 @@ stdenvNoCC.mkDerivation {
       let
         enable_fp = !targetPlatform.isx86_32 && !targetPlatform.isS390;
         enable_leaf_fp =
-          enable_fp
+          !isFlang
+          && enable_fp
           && (
             targetPlatform.isx86_64
             || targetPlatform.isAarch64
@@ -927,7 +938,7 @@ stdenvNoCC.mkDerivation {
     # well with multi line flags, so make the flags single line again
     + ''
       for flags in "$out/nix-support"/*flags*; do
-        substituteInPlace "$flags" --replace $'\n' ' '
+        substituteInPlace "$flags" --replace-quiet $'\n' ' '
       done
 
       substituteAll ${./add-flags.sh} $out/nix-support/add-flags.sh
@@ -973,6 +984,7 @@ stdenvNoCC.mkDerivation {
 
   env = {
     inherit isClang;
+    inherit isFlang;
 
     # for substitution in utils.bash
     # TODO(@sternenseemann): invent something cleaner than passing in "" in case of absence

pkgs/development/compilers/llvm/common/clang/default.nix

@@ -16,6 +16,7 @@
   fixDarwinDylibNames,
   enableManpages ? false,
   enableClangToolsExtra ? true,
+  extraPatches ? [ ],
   devExtraCmakeFlags ? [ ],
   replaceVars,
   getVersionFile,
@@ -73,7 +74,8 @@ stdenv.mkDerivation (
       ];
       stripLen = 1;
       hash = "sha256-1NKej08R9SPlbDY/5b0OKUsHjX07i9brR84yXiPwi7E=";
-    });
+    })
+    ++ extraPatches;
 
     nativeBuildInputs = [
       cmake
@@ -189,6 +191,8 @@ stdenv.mkDerivation (
     passthru = {
       inherit libllvm;
       isClang = true;
+      langC = true;
+      langCC = true;
       hardeningUnsupportedFlagsByTargetPlatform =
         targetPlatform:
         [ "fortify3" ]