add more comments and change changelog.d/pr-10969.md

Author: zlonast

Cabal/src/Distribution/Simple/GHC/Build/ExtraSources.hs

@@ -78,8 +78,15 @@ buildCSources mbMainFile =
         (Internal.sourcesGhcOptions verbosity lbi bi clbi odir filename)
           { -- C++ compiler options: GHC >= 8.10 requires -optcxx, older requires -optc
             -- we want to be able to support cxx-options and cc-options separately
-            ghcOptCxxOptions = Internal.separateGhcOptions (mkVersion [8, 10]) (compiler lbi) (Internal.defaultGhcOptCxxOptions lbi bi)
-          , -- there are problems with linking with versions lower than 9.4, that's why we need this duplication
+            -- see example in cabal-testsuite/PackageTests/FFI/ForeignOptsC
+            ghcOptCxxOptions =
+              Internal.separateGhcOptions
+                (mkVersion [8, 10])
+                (compiler lbi)
+                (Internal.defaultGhcOptCxxOptions lbi bi)
+          , -- there are problems with linking with versions below 9.4,
+            -- that's why we need this replacement for linkGhcOptions
+            -- see example in cabal-testsuite/PackageTests/ShowBuildInfo/Complex
             ghcOptCcProgram = Internal.defaultGhcOptCcProgram lbi
           }
     )
@@ -99,8 +106,15 @@ buildCxxSources mbMainFile =
         (Internal.sourcesGhcOptions verbosity lbi bi clbi odir filename)
           { -- C++ compiler options: GHC >= 8.10 requires -optcxx, older requires -optc
             -- we want to be able to support cxx-options and cc-options separately
-            ghcOptCcOptions = Internal.separateGhcOptions (mkVersion [8, 10]) (compiler lbi) (Internal.defaultGhcOptCcOptions lbi bi)
-          , -- there are problems with linking with versions lower than 9.4, that's why we need this duplication
+            -- see example in cabal-testsuite/PackageTests/FFI/ForeignOptsCxx
+            ghcOptCcOptions =
+              Internal.separateGhcOptions
+                (mkVersion [8, 10])
+                (compiler lbi)
+                (Internal.defaultGhcOptCcOptions lbi bi)
+          , -- there are problems with linking with versions below 9.4,
+            -- that's why we need this replacement for linkGhcOptions
+            -- see example in cabal-testsuite/PackageTests/ShowBuildInfo/Complex
             ghcOptCcProgram = Internal.defaultGhcOptCcProgram lbi
           }
     )

Cabal/src/Distribution/Simple/GHC/Internal.hs

@@ -399,8 +399,14 @@ sourcesGhcOptions verbosity lbi bi clbi odir filename =
 optimizationCFlags :: LocalBuildInfo -> [String]
 optimizationCFlags lbi =
   ( case withOptimization lbi of
+      -- see --disable-optimization
       NoOptimisation -> []
-      NormalOptimisation -> ["-O1"]
+      -- '*-options: -O[n]' is generally not needed. When building with
+      -- optimisations Cabal automatically adds '-O2' for * code. Setting it
+      -- yourself interferes with the --disable-optimization flag.
+      -- see https://github.com/haskell/cabal/pull/8250
+      NormalOptimisation -> ["-O2"]
+      -- see --enable-optimization
       MaximumOptimisation -> ["-O2"]
   )
     ++ ( case withDebugInfo lbi of
@@ -420,6 +426,7 @@ defaultGhcOptCcProgram :: LocalBuildInfo -> Flag FilePath
 defaultGhcOptCcProgram lbi =
   maybeToFlag $ programPath <$> lookupProgram gccProgram (withPrograms lbi)
 
+-- we want to be able to support C++ and C separately in older ghc
 separateGhcOptions :: Monoid a => Version -> Compiler -> a -> a
 separateGhcOptions ver comp defaultOptions =
   case compilerCompatVersion GHC comp of
@@ -473,7 +480,10 @@ linkGhcOptions verbosity lbi bi clbi =
         , ghcOptExtra = hcOptions GHC bi <> cmmOptions bi
         , ghcOptCabal = toFlag True
         , ghcOptCcProgram =
-            separateGhcOptions (mkVersion [9, 4]) (compiler lbi) (defaultGhcOptCcProgram lbi)
+            separateGhcOptions
+              (mkVersion [9, 4])
+              (compiler lbi)
+              (defaultGhcOptCcProgram lbi)
         , ghcOptThisUnitId = case clbi of
             LibComponentLocalBuildInfo{componentCompatPackageKey = pk} ->
               toFlag pk

Cabal/src/Distribution/Simple/GHCJS.hs

@@ -1435,17 +1435,20 @@ gbuild verbosity numJobs pkg_descr lbi bm clbi = do
     sequence_
       [ do
         let baseCxxOpts =
-              ( Internal.sourcesGhcOptions verbosity lbi bnfo clbi tmpDir filename
-                  <> mempty
-                    { ghcOptCcOptions =
-                        ( case compilerCompatVersion GHC comp of
-                            Just v
-                              | v >= mkVersion [8, 10] -> Internal.defaultGhcOptCcOptions lbi bnfo
-                            Just _ -> []
-                            Nothing -> []
-                        )
-                    }
-              )
+              (Internal.sourcesGhcOptions verbosity lbi bnfo clbi odir filename)
+                { -- C++ compiler options: GHC >= 8.10 requires -optcxx, older requires -optc
+                  -- we want to be able to support cxx-options and cc-options separately
+                  -- see example in cabal-testsuite/PackageTests/FFI/ForeignOptsCxx
+                  ghcOptCcOptions =
+                    Internal.separateGhcOptions
+                      (mkVersion [8, 10])
+                      (compiler lbi)
+                      (Internal.defaultGhcOptCcOptions lbi bnfo)
+                , -- there are problems with linking with versions below 9.4,
+                  -- that's why we need this replacement for linkGhcOptions
+                  -- see example in cabal-testsuite/PackageTests/ShowBuildInfo/Complex
+                  ghcOptCcProgram = Internal.defaultGhcOptCcProgram lbi
+                }
             vanillaCxxOpts =
               if isGhcDynamic
                 then -- Dynamic GHC requires C++ sources to be built
@@ -1484,7 +1487,21 @@ gbuild verbosity numJobs pkg_descr lbi bm clbi = do
     info verbosity "Building C Sources..."
     sequence_
       [ do
-        let baseCcOpts = Internal.sourcesGhcOptions verbosity lbi bnfo clbi tmpDir filename
+        let baseCcOpts =
+              (Internal.sourcesGhcOptions verbosity lbi bnfo clbi tmpDir filename)
+                { -- C++ compiler options: GHC >= 8.10 requires -optcxx, older requires -optc
+                  -- we want to be able to support cxx-options and cc-options separately
+                  -- see example in cabal-testsuite/PackageTests/FFI/ForeignOptsC
+                  ghcOptCxxOptions =
+                    Internal.separateGhcOptions
+                      (mkVersion [8, 10])
+                      (compiler lbi)
+                      (Internal.defaultGhcOptCxxOptions lbi bnfo)
+                , -- there are problems with linking with versions below 9.4,
+                  -- that's why we need this replacement for linkGhcOptions
+                  -- see example in cabal-testsuite/PackageTests/ShowBuildInfo/Complex
+                  ghcOptCcProgram = Internal.defaultGhcOptCcProgram lbi
+                }
             vanillaCcOpts =
               if isGhcDynamic
                 then -- Dynamic GHC requires C sources to be built

cabal-testsuite/PackageTests/JS/JSPPOptions/README.md

@@ -0,0 +1,3 @@
+# JSPPOptions
+
+This asserts that cabal passes `jspp-options` to the JavaScript-preprocessor.