Revert "Pass preprocessor options to C compiler when building foreign C files (#16737)"

This reverts commit 1c18d3b41f897f34a93669edaebe6069f319f9e2.

5 files changed, 4 insertions, 57 deletions

diff --git a/compiler/main/DriverPipeline.hs b/compiler/main/DriverPipeline.hs
index bf79ea5d02..366de193c7 100644
--- a/compiler/main/DriverPipeline.hs
+++ b/compiler/main/DriverPipeline.hs
@@ -1193,6 +1193,9 @@ runPhase (RealPhase Cmm) input_fn dflags
 -----------------------------------------------------------------------------
 -- Cc phase
 
+-- we don't support preprocessing .c files (with -E) now.  Doing so introduces
+-- way too many hacks, and I can't say I've ever used it anyway.
+
 runPhase (RealPhase cc_phase) input_fn dflags
    | any (cc_phase `eqPhase`) [Cc, Ccxx, HCc, Cobjc, Cobjcxx]
    = do
@@ -1214,16 +1217,6 @@ runPhase (RealPhase cc_phase) input_fn dflags
               (includePathsQuote cmdline_include_paths)
         let include_paths = include_paths_quote ++ include_paths_global
 
-        -- pass -D or -optP to preprocessor when compiling foreign C files
-        -- (#16737). Doing it in this way is simpler and also enable the C
-        -- compiler to performs preprocessing and parsing in a single pass,
-        -- but it may introduce inconsistency if a different pgm_P is specified.
-        let more_preprocessor_opts = concat
-              [ ["-Xpreprocessor", i]
-              | not hcc
-              , i <- getOpts dflags opt_P
-              ]
-
         let gcc_extra_viac_flags = extraGccViaCFlags dflags
         let pic_c_flags = picCCOpts dflags
 
@@ -1233,7 +1226,7 @@ runPhase (RealPhase cc_phase) input_fn dflags
         -- hc code doesn't not #include any header files anyway, so these
         -- options aren't necessary.
         pkg_extra_cc_opts <- liftIO $
-          if hcc
+          if cc_phase `eqPhase` HCc
              then return []
              else getPackageExtraCcOpts dflags pkgs
 
@@ -1324,7 +1317,6 @@ runPhase (RealPhase cc_phase) input_fn dflags
                        ++ [ "-include", ghcVersionH ]
                        ++ framework_paths
                        ++ include_paths
-                       ++ more_preprocessor_opts
                        ++ pkg_extra_cc_opts
                        ))
 
diff --git a/testsuite/tests/driver/T16737.hs b/testsuite/tests/driver/T16737.hs
deleted file mode 100644
index 0abe5457b0..0000000000
--- a/testsuite/tests/driver/T16737.hs
+++ /dev/null
@@ -1,32 +0,0 @@
-{-# LANGUAGE TemplateHaskell #-}
-{-# OPTIONS_GHC -DFOO=2 -optP=-DBAR=3 -optc=-DBAZ=5 #-}
-
-import Language.Haskell.TH.Syntax
-
-do
-  let code = unlines
-        [ "#if defined(__cplusplus)"
-        , "extern \"C\" {"
-        , "#endif"
-        , "#include <T16737.h>"
-        , "int FUN(void) {"
-        , "  return FOO * BAR * BAZ;"
-        , "}"
-        , "#if defined(__cplusplus)"
-        , "}"
-        , "#endif"
-        ]
-  addForeignSource LangC code
-  addForeignSource LangCxx code
-  pure []
-
-foreign import ccall unsafe "c_value"
-  c_value :: IO Int
-
-foreign import ccall unsafe "cxx_value"
-  cxx_value :: IO Int
-
-main :: IO ()
-main = do
-  print =<< c_value
-  print =<< cxx_value
diff --git a/testsuite/tests/driver/T16737.stdout b/testsuite/tests/driver/T16737.stdout
deleted file mode 100644
index 285b16f691..0000000000
--- a/testsuite/tests/driver/T16737.stdout
+++ /dev/null
@@ -1,2 +0,0 @@
-30
-30
diff --git a/testsuite/tests/driver/T16737include/T16737.h b/testsuite/tests/driver/T16737include/T16737.h
deleted file mode 100644
index 08c7ca8729..0000000000
--- a/testsuite/tests/driver/T16737include/T16737.h
+++ /dev/null
@@ -1,7 +0,0 @@
-#pragma once
-
-#if defined(__cplusplus)
-#define FUN cxx_value
-#else
-#define FUN c_value
-#endif
diff --git a/testsuite/tests/driver/all.T b/testsuite/tests/driver/all.T
index 668d609747..02eeeb321b 100644
--- a/testsuite/tests/driver/all.T
+++ b/testsuite/tests/driver/all.T
@@ -287,7 +287,3 @@ test('inline-check', omit_ways(['hpc', 'profasm'])
 
 test('T14452', [], run_command, ['$MAKE -s --no-print-directory T14452'])
 test('T15396', normal, compile_and_run, ['-package ghc'])
-test('T16737',
-     [when(ghc_dynamic(), omit_ways(['profasm'])), extra_files(['T16737include/'])],
-     compile_and_run,
-     ['-optP=-isystem -optP=T16737include'])