From c0981da47d5696fe36474fcf86b4ce03ae3ff818 Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Fri, 19 Nov 2021 21:06:13 +0100
Subject: Vendor import of llvm-project main
 llvmorg-14-init-10186-gff7f2cfa959b.

---
 llvm/lib/Transforms/Utils/SplitModule.cpp | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

(limited to 'llvm/lib/Transforms/Utils/SplitModule.cpp')

diff --git a/llvm/lib/Transforms/Utils/SplitModule.cpp b/llvm/lib/Transforms/Utils/SplitModule.cpp
index 32f2f4e233b2..7e12bbd2851c 100644
--- a/llvm/lib/Transforms/Utils/SplitModule.cpp
+++ b/llvm/lib/Transforms/Utils/SplitModule.cpp
@@ -24,7 +24,6 @@
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalObject.h"
-#include "llvm/IR/GlobalIndirectSymbol.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/IR/Instruction.h"
@@ -65,9 +64,8 @@ static void addNonConstUser(ClusterMapType &GVtoClusterMap,
   if (const Instruction *I = dyn_cast<Instruction>(U)) {
     const GlobalValue *F = I->getParent()->getParent();
     GVtoClusterMap.unionSets(GV, F);
-  } else if (isa<GlobalIndirectSymbol>(U) || isa<Function>(U) ||
-             isa<GlobalVariable>(U)) {
-    GVtoClusterMap.unionSets(GV, cast<GlobalValue>(U));
+  } else if (const GlobalValue *GVU = dyn_cast<GlobalValue>(U)) {
+    GVtoClusterMap.unionSets(GV, GVU);
   } else {
     llvm_unreachable("Underimplemented use case");
   }
@@ -91,6 +89,13 @@ static void addAllGlobalValueUsers(ClusterMapType &GVtoClusterMap,
   }
 }
 
+static const GlobalObject *getGVPartitioningRoot(const GlobalValue *GV) {
+  const GlobalObject *GO = GV->getAliaseeObject();
+  if (const auto *GI = dyn_cast_or_null<GlobalIFunc>(GO))
+    GO = GI->getResolverFunction();
+  return GO;
+}
+
 // Find partitions for module in the way that no locals need to be
 // globalized.
 // Try to balance pack those partitions into N files since this roughly equals
@@ -123,12 +128,11 @@ static void findPartitions(Module &M, ClusterIDMapType &ClusterIDMap,
         Member = &GV;
     }
 
-    // For aliases we should not separate them from their aliasees regardless
-    // of linkage.
-    if (auto *GIS = dyn_cast<GlobalIndirectSymbol>(&GV)) {
-      if (const GlobalObject *Base = GIS->getBaseObject())
-        GVtoClusterMap.unionSets(&GV, Base);
-    }
+    // Aliases should not be separated from their aliasees and ifuncs should
+    // not be separated from their resolvers regardless of linkage.
+    if (const GlobalObject *Root = getGVPartitioningRoot(&GV))
+      if (&GV != Root)
+        GVtoClusterMap.unionSets(&GV, Root);
 
     if (const Function *F = dyn_cast<Function>(&GV)) {
       for (const BasicBlock &BB : *F) {
@@ -225,9 +229,8 @@ static void externalize(GlobalValue *GV) {
 
 // Returns whether GV should be in partition (0-based) I of N.
 static bool isInPartition(const GlobalValue *GV, unsigned I, unsigned N) {
-  if (auto *GIS = dyn_cast<GlobalIndirectSymbol>(GV))
-    if (const GlobalObject *Base = GIS->getBaseObject())
-      GV = Base;
+  if (const GlobalObject *Root = getGVPartitioningRoot(GV))
+    GV = Root;
 
   StringRef Name;
   if (const Comdat *C = GV->getComdat())
-- 
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