[Git][ghc/ghc][wip/fllvm-error] driver: bail out when -fllvm is passed to GHC not configured with LLVM

[Rodrigo Mesquita (@alt-romes)]

Rodrigo Mesquita pushed to branch wip/fllvm-error at Glasgow Haskell Compiler / GHC


Commits:
4628f7d2 by Cheng Shao at 2024-10-03T14:00:37+01:00
driver: bail out when -fllvm is passed to GHC not configured with LLVM

This patch makes GHC bail out with an proper error message when it's
not configured with LLVM but users attempt to pass -fllvm, see #25011
and added comment for details.

Co-authored-by: Rodrigo Mesquita <rodrigo.m.mesquita at gmail.com>

- - - - -


4 changed files:

- compiler/GHC/Driver/Errors/Ppr.hs
- compiler/GHC/Driver/Errors/Types.hs
- compiler/GHC/SysTools/Tasks.hs
- compiler/GHC/Types/Error/Codes.hs


Changes:

=====================================
compiler/GHC/Driver/Errors/Ppr.hs
=====================================
@@ -35,6 +35,7 @@ import GHC.HsToCore.Errors.Types (DsMessage)
 import GHC.Iface.Errors.Types
 import GHC.Tc.Errors.Ppr () -- instance Diagnostic TcRnMessage
 import GHC.Iface.Errors.Ppr () -- instance Diagnostic IfaceMessage
+import GHC.CmmToLlvm.Version (llvmVersionStr, supportedLlvmVersionLowerBound, supportedLlvmVersionUpperBound)
 
 --
 -- Suggestions
@@ -268,6 +269,14 @@ instance Diagnostic DriverMessage where
       mkSimpleDecorated $
         vcat [ text "Unexpected backpack instantiation in dependency graph while constructing Makefile:"
              , nest 2 $ ppr node ]
+    DriverNoConfiguredLLVMToolchain ->
+      mkSimpleDecorated $
+        text "GHC was not configured with a supported LLVM toolchain" $$
+          text ("Make sure you have installed LLVM between ["
+            ++ llvmVersionStr supportedLlvmVersionLowerBound
+            ++ " and "
+            ++ llvmVersionStr supportedLlvmVersionUpperBound
+            ++ ") and reinstall GHC to make -fllvm work")
 
   diagnosticReason = \case
     DriverUnknownMessage m
@@ -337,6 +346,8 @@ instance Diagnostic DriverMessage where
       -> ErrorWithoutFlag
     DriverInstantiationNodeInDependencyGeneration {}
       -> ErrorWithoutFlag
+    DriverNoConfiguredLLVMToolchain
+      -> ErrorWithoutFlag
 
   diagnosticHints = \case
     DriverUnknownMessage m
@@ -408,5 +419,7 @@ instance Diagnostic DriverMessage where
       -> noHints
     DriverInstantiationNodeInDependencyGeneration {}
       -> noHints
+    DriverNoConfiguredLLVMToolchain
+      -> noHints
 
   diagnosticCode = constructorCode


=====================================
compiler/GHC/Driver/Errors/Types.hs
=====================================
@@ -402,6 +402,14 @@ data DriverMessage where
        Backpack 'InstantiationNode's. -}
   DriverInstantiationNodeInDependencyGeneration :: InstantiatedUnit -> DriverMessage
 
+  {-| DriverNoConfiguredLLVMToolchain is an error that occurs if there is no
+     LLVM toolchain configured but -fllvm is passed as an option to the compiler.
+
+    Test cases: None.
+
+  -}
+  DriverNoConfiguredLLVMToolchain :: DriverMessage
+
 deriving instance Generic DriverMessage
 
 data DriverMessageOpts =


=====================================
compiler/GHC/SysTools/Tasks.hs
=====================================
@@ -19,7 +19,6 @@ import GHC.Settings
 import GHC.SysTools.Process
 
 import GHC.Driver.Session
-
 import GHC.Utils.Exception as Exception
 import GHC.Utils.Error
 import GHC.Utils.Outputable
@@ -28,10 +27,16 @@ import GHC.Utils.Logger
 import GHC.Utils.TmpFs
 import GHC.Utils.Panic
 
+import Control.Monad
 import Data.List (tails, isPrefixOf)
 import Data.Maybe (fromMaybe)
 import System.IO
 import System.Process
+import GHC.Driver.Config.Diagnostic
+import GHC.Driver.Errors
+import GHC.Driver.Errors.Types (GhcMessage(..), DriverMessage (DriverNoConfiguredLLVMToolchain))
+import GHC.Driver.CmdLine (warnsToMessages)
+import GHC.Types.SrcLoc (noLoc)
 
 {-
 ************************************************************************
@@ -277,12 +282,26 @@ runEmscripten logger dflags args = traceSystoolCommand logger "emcc" $ do
 figureLlvmVersion :: Logger -> DynFlags -> IO (Maybe LlvmVersion)
 figureLlvmVersion logger dflags = traceSystoolCommand logger "llc" $ do
   let (pgm,opts) = pgm_lc dflags
+      diag_opts = initDiagOpts dflags
       args = filter notNull (map showOpt opts)
       -- we grab the args even though they should be useless just in
       -- case the user is using a customised 'llc' that requires some
       -- of the options they've specified. llc doesn't care what other
       -- options are specified when '-version' is used.
       args' = args ++ ["-version"]
+  -- Since !12001, when GHC is not configured with llc/opt with
+  -- supported version range, configure script will leave llc/opt
+  -- commands as blank in settings. In this case, we should bail out
+  -- with a proper error, see #25011.
+  --
+  -- Note that this does not make the -Wunsupported-llvm-version
+  -- warning logic redundant! Power users might want to use
+  -- -pgmlc/-pgmlo to override llc/opt locations to test LLVM outside
+  -- officially supported version range, and the driver will produce
+  -- the warning and carry on code generation.
+  when (null pgm) $
+    printOrThrowDiagnostics logger (initPrintConfig dflags) diag_opts
+      (GhcDriverMessage <$> warnsToMessages diag_opts [noLoc DriverNoConfiguredLLVMToolchain])
   catchIO (do
               (pin, pout, perr, p) <- runInteractiveProcess pgm args'
                                               Nothing Nothing
@@ -360,4 +379,3 @@ runWindres logger dflags args = traceSystoolCommand logger "windres" $ do
       opts = map Option (getOpts dflags opt_windres)
   mb_env <- getGccEnv cc_args
   runSomethingFiltered logger id "Windres" windres (opts ++ args) Nothing mb_env
-


=====================================
compiler/GHC/Types/Error/Codes.hs
=====================================
@@ -324,6 +324,7 @@ type family GhcDiagnosticCode c = n | n -> c where
   GhcDiagnosticCode "DriverDeprecatedFlag"                          = 53692
   GhcDiagnosticCode "DriverModuleGraphCycle"                        = 92213
   GhcDiagnosticCode "DriverInstantiationNodeInDependencyGeneration" = 74284
+  GhcDiagnosticCode "DriverNoConfiguredLLVMToolchain"               = 66599
 
   -- Constraint solver diagnostic codes
   GhcDiagnosticCode "BadTelescope"                                  = 97739



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/4628f7d20e0e4cbe010d891d95f17596815c4334

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/4628f7d20e0e4cbe010d891d95f17596815c4334
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