From 73e0aa58666f235bef091735a5f189882acc1148 Mon Sep 17 00:00:00 2001
From: Jessica Clarke <jrtc27@jrtc27.com>
Date: Wed, 28 Aug 2024 17:11:15 +0100
Subject: [CodeGen] Create IFUNCs in the program address space, not hard-coded
 0 (#105726)

Commit 0d527e56a5ee ("GlobalIFunc: Make ifunc respect function address
spaces") added support for this within LLVM, but Clang does not properly
honour the target's address spaces when creating IFUNCs, crashing with
RAUW and verifier assertion failures when compiling C code on a target
with a non-zero program address space, so fix this.
---
 clang/lib/CodeGen/CodeGenModule.cpp | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

(limited to 'clang/lib/CodeGen/CodeGenModule.cpp')

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 42742ae..df4c13c 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4455,12 +4455,13 @@ void CodeGenModule::emitCPUDispatchDefinition(GlobalDecl GD) {
   if (getTarget().supportsIFunc()) {
     llvm::GlobalValue::LinkageTypes Linkage = getMultiversionLinkage(*this, GD);
     auto *IFunc = cast<llvm::GlobalValue>(GetOrCreateMultiVersionResolver(GD));
+    unsigned AS = IFunc->getType()->getPointerAddressSpace();
 
     // Fix up function declarations that were created for cpu_specific before
     // cpu_dispatch was known
     if (!isa<llvm::GlobalIFunc>(IFunc)) {
-      auto *GI = llvm::GlobalIFunc::create(DeclTy, 0, Linkage, "", ResolverFunc,
-                                           &getModule());
+      auto *GI = llvm::GlobalIFunc::create(DeclTy, AS, Linkage, "",
+                                           ResolverFunc, &getModule());
       replaceDeclarationWith(IFunc, GI);
       IFunc = GI;
     }
@@ -4469,8 +4470,8 @@ void CodeGenModule::emitCPUDispatchDefinition(GlobalDecl GD) {
         *this, GD, FD, /*OmitMultiVersionMangling=*/true);
     llvm::Constant *AliasFunc = GetGlobalValue(AliasName);
     if (!AliasFunc) {
-      auto *GA = llvm::GlobalAlias::create(DeclTy, 0, Linkage, AliasName, IFunc,
-                                           &getModule());
+      auto *GA = llvm::GlobalAlias::create(DeclTy, AS, Linkage, AliasName,
+                                           IFunc, &getModule());
       SetCommonAttributes(GD, GA);
     }
   }
@@ -4542,15 +4543,14 @@ llvm::Constant *CodeGenModule::GetOrCreateMultiVersionResolver(GlobalDecl GD) {
   // For cpu_specific, don't create an ifunc yet because we don't know if the
   // cpu_dispatch will be emitted in this translation unit.
   if (getTarget().supportsIFunc() && !FD->isCPUSpecificMultiVersion()) {
-    llvm::Type *ResolverType = llvm::FunctionType::get(
-        llvm::PointerType::get(DeclTy,
-                               getTypes().getTargetAddressSpace(FD->getType())),
-        false);
+    unsigned AS = getTypes().getTargetAddressSpace(FD->getType());
+    llvm::Type *ResolverType =
+        llvm::FunctionType::get(llvm::PointerType::get(DeclTy, AS), false);
     llvm::Constant *Resolver = GetOrCreateLLVMFunction(
         MangledName + ".resolver", ResolverType, GlobalDecl{},
         /*ForVTable=*/false);
     llvm::GlobalIFunc *GIF =
-        llvm::GlobalIFunc::create(DeclTy, 0, getMultiversionLinkage(*this, GD),
+        llvm::GlobalIFunc::create(DeclTy, AS, getMultiversionLinkage(*this, GD),
                                   "", Resolver, &getModule());
     GIF->setName(ResolverName);
     SetCommonAttributes(FD, GIF);
@@ -6160,9 +6160,9 @@ void CodeGenModule::emitIFuncDefinition(GlobalDecl GD) {
       GetOrCreateLLVMFunction(IFA->getResolver(), VoidTy, {},
                               /*ForVTable=*/false);
   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
-  llvm::GlobalIFunc *GIF =
-      llvm::GlobalIFunc::create(DeclTy, 0, llvm::Function::ExternalLinkage,
-                                "", Resolver, &getModule());
+  unsigned AS = getTypes().getTargetAddressSpace(D->getType());
+  llvm::GlobalIFunc *GIF = llvm::GlobalIFunc::create(
+      DeclTy, AS, llvm::Function::ExternalLinkage, "", Resolver, &getModule());
   if (Entry) {
     if (GIF->getResolver() == Entry) {
       Diags.Report(IFA->getLocation(), diag::err_cyclic_alias) << 1;
-- 
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