[Git][ghc/ghc][wip/T23870] llvmGen: Don't pass stack alignment via command line

[Ben Gamari (@bgamari)]

Ben Gamari pushed to branch wip/T23870 at Glasgow Haskell Compiler / GHC


Commits:
a0de5f25 by Ben Gamari at 2023-08-22T13:29:46-04:00
llvmGen: Don't pass stack alignment via command line

As of https://reviews.llvm.org/D103048 LLVM no longer supports the
`-stack-alignment=...` flag. Instead this information is passed via a
module flag metadata node.

This requires dropping support for LLVM 11 and 12.

Fixes #23870

- - - - -


5 changed files:

- compiler/GHC/CmmToLlvm.hs
- compiler/GHC/CmmToLlvm/Config.hs
- compiler/GHC/Driver/Config/CmmToLlvm.hs
- compiler/GHC/Driver/Pipeline/Execute.hs
- configure.ac


Changes:

=====================================
compiler/GHC/CmmToLlvm.hs
=====================================
@@ -196,7 +196,7 @@ cmmLlvmGen _ = return ()
 
 cmmMetaLlvmPrelude :: LlvmM ()
 cmmMetaLlvmPrelude = do
-  metas <- flip mapM stgTBAA $ \(uniq, name, parent) -> do
+  tbaa_metas <- flip mapM stgTBAA $ \(uniq, name, parent) -> do
     -- Generate / lookup meta data IDs
     tbaaId <- getMetaUniqueId
     setUniqMeta uniq tbaaId
@@ -209,10 +209,37 @@ cmmMetaLlvmPrelude = do
               -- just a name on its own. Previously `null` was accepted as the
               -- name.
               Nothing -> [ MetaStr name ]
+
+  platform <- getPlatform
+  cfg <- getConfig
+  let stack_alignment_metas =
+          case platformArch platform of
+            ArchX86_64 | llvmCgAvxEnabled cfg -> [mkStackAlignmentMeta 32]
+            _                                 -> []
+  module_flags_metas <- mkModuleFlagsMeta stack_alignment_metas
+  let metas = tbaa_metas ++ module_flags_metas
   cfg <- getConfig
   renderLlvm (ppLlvmMetas cfg metas)
              (ppLlvmMetas cfg metas)
 
+mkNamedMeta :: LMString -> [MetaExpr] -> LlvmM [MetaDecl]
+mkNamedMeta name exprs = do
+    (ids, decls) <- unzip <$> mapM f exprs
+    return $ decls ++ [MetaNamed name ids]
+  where
+    f expr = do
+      i <- getMetaUniqueId
+      return (i, MetaUnnamed i expr)
+
+mkModuleFlagsMeta :: [ModuleFlag] -> LlvmM [MetaDecl]
+mkModuleFlagsMeta =
+    mkNamedMeta "llvm.module.flags" . map moduleFlagToMetaExpr
+
+mkStackAlignmentMeta :: Integer -> ModuleFlag
+mkStackAlignmentMeta alignment =
+    ModuleFlag MFBError "override-stack-alignment" (MetaLit $ LMIntLit alignment i32)
+
+
 -- -----------------------------------------------------------------------------
 -- | Marks variables as used where necessary
 --


=====================================
compiler/GHC/CmmToLlvm/Config.hs
=====================================
@@ -36,6 +36,7 @@ data LlvmCgConfig = LlvmCgConfig
   , llvmCgContext           :: !SDocContext  -- ^ Context for LLVM code generation
   , llvmCgFillUndefWithGarbage :: !Bool      -- ^ Fill undefined literals with garbage values
   , llvmCgSplitSection      :: !Bool         -- ^ Split sections
+  , llvmCgAvxEnabled        :: !Bool
   , llvmCgBmiVersion        :: Maybe BmiVersion  -- ^ (x86) BMI instructions
   , llvmCgLlvmVersion       :: Maybe LlvmVersion -- ^ version of Llvm we're using
   , llvmCgDoWarn            :: !Bool         -- ^ True ==> warn unsupported Llvm version


=====================================
compiler/GHC/Driver/Config/CmmToLlvm.hs
=====================================
@@ -23,6 +23,7 @@ initLlvmCgConfig logger config_cache dflags = do
     , llvmCgContext              = initSDocContext dflags PprCode
     , llvmCgFillUndefWithGarbage = gopt Opt_LlvmFillUndefWithGarbage dflags
     , llvmCgSplitSection         = gopt Opt_SplitSections dflags
+    , llvmCgAvxEnabled           = isAvxEnabled dflags
     , llvmCgBmiVersion           = case platformArch (targetPlatform dflags) of
                                       ArchX86_64 -> bmiVersion dflags
                                       ArchX86    -> bmiVersion dflags


=====================================
compiler/GHC/Driver/Pipeline/Execute.hs
=====================================
@@ -948,8 +948,6 @@ llvmOptions llvm_config dflags =
        [("-enable-tbaa -tbaa",  "-enable-tbaa") | gopt Opt_LlvmTBAA dflags ]
     ++ [("-relocation-model=" ++ rmodel
         ,"-relocation-model=" ++ rmodel) | not (null rmodel)]
-    ++ [("-stack-alignment=" ++ (show align)
-        ,"-stack-alignment=" ++ (show align)) | align > 0 ]
 
     -- Additional llc flags
     ++ [("", "-mcpu=" ++ mcpu)   | not (null mcpu)
@@ -968,11 +966,6 @@ llvmOptions llvm_config dflags =
 
         platform = targetPlatform dflags
 
-        align :: Int
-        align = case platformArch platform of
-                  ArchX86_64 | isAvxEnabled dflags -> 32
-                  _                                -> 0
-
         attrs :: String
         attrs = intercalate "," $ mattr
               ++ ["+sse42"   | isSse4_2Enabled dflags   ]


=====================================
configure.ac
=====================================
@@ -547,7 +547,7 @@ AC_SUBST(InstallNameToolCmd)
 # tools we are looking for. In the past, GHC supported a number of
 # versions of LLVM simultaneously, but that stopped working around
 # 3.5/3.6 release of LLVM.
-LlvmMinVersion=11  # inclusive
+LlvmMinVersion=13  # inclusive
 LlvmMaxVersion=16 # not inclusive
 AC_SUBST([LlvmMinVersion])
 AC_SUBST([LlvmMaxVersion])



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/a0de5f25fe45cfee604e068d6e2e8997e101f1f7

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/a0de5f25fe45cfee604e068d6e2e8997e101f1f7
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