From 3b0d80ff6f80ca3e473b0c9a3db0c6bb7fa35bab Mon Sep 17 00:00:00 2001
From: Xin Wang <wangxin03@loongson.cn>
Date: Fri, 13 Dec 2024 10:45:20 +0800
Subject: [PATCH] [PATCH] llvmGen: Pass mcmodel medium option to LLVM backend
 on LoongArch

Gbp-Pq: Name 0004-llvmGen-Pass-mcmodel-medium-option-to-LLVM-backend-on-LoongArch.patch
---
 compiler/GHC/CmmToLlvm.hs     | 36 ++++++++++++++++++++++++++++++++++-
 compiler/GHC/Llvm/MetaData.hs |  1 -
 configure.ac                  |  2 +-
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/compiler/GHC/CmmToLlvm.hs b/compiler/GHC/CmmToLlvm.hs
index ea588440..04a542c5 100644
--- a/compiler/GHC/CmmToLlvm.hs
+++ b/compiler/GHC/CmmToLlvm.hs
@@ -190,7 +190,7 @@ 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
@@ -203,9 +203,43 @@ cmmMetaLlvmPrelude = do
               -- just a name on its own. Previously `null` was accepted as the
               -- name.
               Nothing -> [ MetaStr name ]
+
+  platform <- getPlatform
+  cfg <- getConfig
+  let code_model_metas =
+          case platformArch platform of
+            -- FIXME: We should not rely on LLVM
+            ArchLoongArch64 -> [mkCodeModelMeta CMMedium]
+            _                                 -> []
+  module_flags_metas <- mkModuleFlagsMeta code_model_metas
+  let metas = tbaa_metas ++ module_flags_metas
   cfg <- getConfig
   renderLlvm $ 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
+
+-- LLVM's @LLVM::CodeModel::Model@ enumeration
+data CodeModel = CMMedium
+
+-- Pass -mcmodel=medium option to LLVM on LoongArch64
+mkCodeModelMeta :: CodeModel -> ModuleFlag
+mkCodeModelMeta codemodel =
+    ModuleFlag MFBError "Code Model" (MetaLit $ LMIntLit n i32)
+  where
+    n = case codemodel of CMMedium -> 3 -- as of LLVM 8
+
+
 -- -----------------------------------------------------------------------------
 -- | Marks variables as used where necessary
 --
diff --git a/compiler/GHC/Llvm/MetaData.hs b/compiler/GHC/Llvm/MetaData.hs
index 2b28be48..5d0a996c 100644
--- a/compiler/GHC/Llvm/MetaData.hs
+++ b/compiler/GHC/Llvm/MetaData.hs
@@ -2,7 +2,6 @@
 
 module GHC.Llvm.MetaData
   ( MetaId(..)
-  , ppMetaId
   , MetaExpr(..)
   , MetaAnnot(..)
   , MetaDecl(..)
diff --git a/configure.ac b/configure.ac
index 02a1eeef..0665af54 100644
--- a/configure.ac
+++ b/configure.ac
@@ -555,7 +555,7 @@ 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=19 # not inclusive
 AC_SUBST([LlvmMinVersion])
 AC_SUBST([LlvmMaxVersion])
-- 
2.30.2