driver: Remove needsTemplateHaskellOrQQ from ModuleGraphwip/driver-things

The idea of the needsTemplateHaskellOrQQ query is to check if any of the
modules in a module graph need Template Haskell then enable -dynamic-too
if necessary. This is quite imprecise though as it will enable
-dynamic-too for all modules in the module graph even if only one module
uses template haskell, with multiple home units, this is obviously even
worse.

With -fno-code we already have similar logic to enable code generation
just for the modules which are dependeded on my TemplateHaskell modules
so we use the same code path to decide whether to enable -dynamic-too
rather than using this big hammer.

This is part of the larger overall goal of moving as much statically
known configuration into the downsweep as possible in order to have
fully decided the build plan and all the options before starting to
build anything.

I also included a fix to #21095, a long standing bug with with the logic
which is supposed to enable the external interpreter if we don't have
the internal interpreter.

Fixes #20696 #21095

1 files changed, 3 insertions, 24 deletions

diff --git a/compiler/GHC/Driver/Pipeline.hs b/compiler/GHC/Driver/Pipeline.hs
index ab1fb9f76f..d66a6074c9 100644
--- a/compiler/GHC/Driver/Pipeline.hs
+++ b/compiler/GHC/Driver/Pipeline.hs
@@ -108,7 +108,6 @@ import GHC.Unit.Env
 --import GHC.Unit.State
 import GHC.Unit.Module.ModSummary
 import GHC.Unit.Module.ModIface
-import GHC.Unit.Module.Graph (needsTemplateHaskellOrQQ)
 import GHC.Unit.Module.Deps
 import GHC.Unit.Home.ModInfo
 
@@ -252,11 +251,6 @@ compileOne' mHscMessage
        location    = ms_location summary
        input_fn    = expectJust "compile:hs" (ml_hs_file location)
        input_fnpp  = ms_hspp_file summary
-       mod_graph   = hsc_mod_graph hsc_env0
-       needsLinker = needsTemplateHaskellOrQQ mod_graph
-       isDynWay    = hasWay (ways lcl_dflags) WayDyn
-       isProfWay   = hasWay (ways lcl_dflags) WayProf
-       internalInterpreter = not (gopt Opt_ExternalInterpreter lcl_dflags)
 
        pipelineOutput = case bcknd of
          Interpreter -> NoOutputFile
@@ -266,28 +260,13 @@ compileOne' mHscMessage
        logger = hsc_logger hsc_env0
        tmpfs  = hsc_tmpfs hsc_env0
 
-       -- #8180 - when using TemplateHaskell, switch on -dynamic-too so
-       -- the linker can correctly load the object files.  This isn't necessary
-       -- when using -fexternal-interpreter.
-       dflags1 = if hostIsDynamic && internalInterpreter &&
-                    not isDynWay && not isProfWay && needsLinker
-                  then gopt_set lcl_dflags Opt_BuildDynamicToo
-                  else lcl_dflags
-
-       -- #16331 - when no "internal interpreter" is available but we
-       -- need to process some TemplateHaskell or QuasiQuotes, we automatically
-       -- turn on -fexternal-interpreter.
-       dflags2 = if not internalInterpreter && needsLinker
-                 then gopt_set dflags1 Opt_ExternalInterpreter
-                 else dflags1
-
        basename = dropExtension input_fn
 
        -- We add the directory in which the .hs files resides) to the import
        -- path.  This is needed when we try to compile the .hc file later, if it
        -- imports a _stub.h file that we created here.
        current_dir = takeDirectory basename
-       old_paths   = includePaths dflags2
+       old_paths   = includePaths lcl_dflags
        loadAsByteCode
          | Just Target { targetAllowObjCode = obj } <- findTarget summary (hsc_targets hsc_env0)
          , not obj
@@ -300,9 +279,9 @@ compileOne' mHscMessage
          -- was set), force it to generate byte-code. This is NOT transitive and
          -- only applies to direct targets.
          | loadAsByteCode
-         = (Interpreter, gopt_set (dflags2 { backend = Interpreter }) Opt_ForceRecomp)
+         = (Interpreter, gopt_set (lcl_dflags { backend = Interpreter }) Opt_ForceRecomp)
          | otherwise
-         = (backend dflags, dflags2)
+         = (backend dflags, lcl_dflags)
        -- See Note [Filepaths and Multiple Home Units]
        dflags  = dflags3 { includePaths = offsetIncludePaths dflags3 $ addImplicitQuoteInclude old_paths [current_dir] }
        upd_summary = summary { ms_hspp_opts = dflags }