[Verifier] Add verification for ifuncs

[ibookstein]

Summary

Signed-off-by: Itay Bookstein <[e-mail]>

clang/lib/CodeGen/CodeGenModule.cpp

 //===--- CodeGenModule.cpp - Emit LLVM Code from ASTs for a Module --------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
if (lookupRepresentativeDecl(MangledName, OtherGD) &&
                    diag::note_previous_definition);
     }
     return;
   }
 
   Aliases.push_back(GD);
 
   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
+  llvm::Type *ResolverTy =
+      llvm::FunctionType::get(DeclTy->getPointerTo(), false);
   llvm::Constant *Resolver =
-      GetOrCreateLLVMFunction(IFA->getResolver(), DeclTy, GD,
+      GetOrCreateLLVMFunction(IFA->getResolver(), ResolverTy, GD,
                               /*ForVTable=*/false);
   llvm::GlobalIFunc *GIF =
       llvm::GlobalIFunc::create(DeclTy, 0, llvm::Function::ExternalLinkage,
                                 "", Resolver, &getModule());
   if (Entry) {
     if (GIF->getResolver() == Entry) {
       Diags.Report(IFA->getLocation(), diag::err_cyclic_alias) << 1;
       return;

llvm/lib/IR/Globals.cpp

 //===-- Globals.cpp - Implement the GlobalValue & GlobalVariable class ----===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //

 }
 
 void GlobalIFunc::eraseFromParent() {
   getParent()->getIFuncList().erase(getIterator());
 }
 
 const Function *GlobalIFunc::getResolverFunction() const {
   DenseSet<const GlobalAlias *> Aliases;
-  return cast<Function>(findBaseObject(getResolver(), Aliases));
+  return dyn_cast<Function>(findBaseObject(getResolver(), Aliases));
 }

llvm/lib/IR/Verifier.cpp

 //===-- Verifier.cpp - Implement the Module Verifier -----------------------==//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
bool verify() {
     // recover a frame index that wasn't escaped.
     verifyFrameRecoverIndices();
     for (const GlobalVariable &GV : M.globals())
       visitGlobalVariable(GV);
 
     for (const GlobalAlias &GA : M.aliases())
       visitGlobalAlias(GA);
 
+    for (const GlobalIFunc &GI : M.ifuncs())
+      visitGlobalIFunc(GI);
+
     for (const NamedMDNode &NMD : M.named_metadata())
       visitNamedMDNode(NMD);
 
     for (const StringMapEntry<Comdat> &SMEC : M.getComdatSymbolTable())
       visitComdat(SMEC.getValue());
 
     visitModuleFlags(M);
     visitModuleIdents(M);

 private:
   /// Whether a metadata node is allowed to be, or contain, a DILocation.
   enum class AreDebugLocsAllowed { No, Yes };
 
   // Verification methods...
   void visitGlobalValue(const GlobalValue &GV);
   void visitGlobalVariable(const GlobalVariable &GV);
   void visitGlobalAlias(const GlobalAlias &GA);
+  void visitGlobalIFunc(const GlobalIFunc &GI);
   void visitAliaseeSubExpr(const GlobalAlias &A, const Constant &C);
   void visitAliaseeSubExpr(SmallPtrSetImpl<const GlobalAlias *> &Visited,
                            const GlobalAlias &A, const Constant &C);
   void visitNamedMDNode(const NamedMDNode &NMD);
   void visitMDNode(const MDNode &MD, AreDebugLocsAllowed AllowLocs);
   void visitMetadataAsValue(const MetadataAsValue &MD, Function *F);
   void visitValueAsMetadata(const ValueAsMetadata &MD, Function *F);
   void visitComdat(const Comdat &C);
void Verifier::visitGlobalAlias(const GlobalAlias &GA) {
   Assert(isa<GlobalValue>(Aliasee) || isa<ConstantExpr>(Aliasee),
          "Aliasee should be either GlobalValue or ConstantExpr", &GA);
 
   visitAliaseeSubExpr(GA, *Aliasee);
 
   visitGlobalValue(GA);
 }
 
+void Verifier::visitGlobalIFunc(const GlobalIFunc &GI) {
+  // Pierce through ConstantExprs and GlobalAliases and check that the resolver
+  // is a Function definition
+  const Function *Resolver = GI.getResolverFunction();
+  Assert(Resolver, "IFunc must have a Function resolver", &GI);
+  Assert(!Resolver->isDeclarationForLinker(),
+         "IFunc resolver must be a definition", &GI);
+
+  // Check that the immediate resolver operand (prior to any bitcasts) has a
+  // pointer-to-function type whose return type matches the ifunc
+  const auto *ResTy = dyn_cast<PointerType>(GI.getResolver()->getType());
+  Assert(ResTy, "IFunc resolver must have a pointer type", &GI);
+  const auto *ResFuncTy = dyn_cast<FunctionType>(ResTy->getElementType());
+  Assert(ResFuncTy, "IFunc resolver type must be pointer to function", &GI);
+  Assert(GI.getType() == ResFuncTy->getReturnType(),
+         "IFunc resolver return type must match IFunc type", &GI);
+}
+
 void Verifier::visitNamedMDNode(const NamedMDNode &NMD) {
   // There used to be various other llvm.dbg.* nodes, but we don't support
   // upgrading them and we want to reserve the namespace for future uses.
   if (NMD.getName().startswith("llvm.dbg."))
     AssertDI(NMD.getName() == "llvm.dbg.cu",
              "unrecognized named metadata node in the llvm.dbg namespace",
              &NMD);
   for (const MDNode *MD : NMD.operands()) {

llvm/test/Assembler/ifunc-asm.ll

 ; RUN: llvm-as < %s | llvm-dis | FileCheck %s
 
 target triple = "x86_64-unknown-linux-gnu"
 
-@foo = ifunc i32 (i32), i64 ()* @foo_ifunc
-; CHECK: @foo = ifunc i32 (i32), i64 ()* @foo_ifunc
+@foo = ifunc i32 (i32), i32 (i32)* ()* @foo_ifunc
+; CHECK: @foo = ifunc i32 (i32), i32 (i32)* ()* @foo_ifunc
 
-define internal i64 @foo_ifunc() {
+@strlen = ifunc i64 (i8*), bitcast (i64 (i32*)* ()* @mistyped_strlen_resolver to i64 (i8*)* ()*)
+; CHECK: strlen = ifunc i64 (i8*), bitcast (i64 (i32*)* ()* @mistyped_strlen_resolver to i64 (i8*)* ()*)
+
+define internal i32 (i32)* @foo_ifunc() {
+entry:
+  ret i32 (i32)* null
+}
+; CHECK: define internal i32 (i32)* @foo_ifunc()
+
+define internal i64 (i32*)* @mistyped_strlen_resolver() {
 entry:
-  ret i64 0
+  ret i64 (i32*)* null
 }
-; CHECK: define internal i64 @foo_ifunc()
+; CHECK: define internal i64 (i32*)* @mistyped_strlen_resolver()

llvm/test/Assembler/ifunc-dsolocal.ll

 ; RUN: llvm-as < %s | llvm-dis | FileCheck %s
 
-@foo = dso_local ifunc i32 (i32), i64 ()* @foo_ifunc
-; CHECK: @foo = dso_local ifunc i32 (i32), i64 ()* @foo_ifunc
+@foo = dso_local ifunc i32 (i32), i32 (i32)* ()* @foo_ifunc
+; CHECK: @foo = dso_local ifunc i32 (i32), i32 (i32)* ()* @foo_ifunc
 
-define internal i64 @foo_ifunc() {
+define internal i32 (i32)* @foo_ifunc() {
 entry:
-  ret i64 0
+  ret i32 (i32)* null
 }

llvm/test/Assembler/ifunc-use-list-order.ll

 ; RUN: verify-uselistorder < %s
 
 ; Global referencing ifunc.
 @ptr_foo = global void ()* @foo_ifunc
 
 ; Alias for ifunc.
 @alias_foo = alias void (), void ()* @foo_ifunc
 
-@foo_ifunc = ifunc void (), i8* ()* @foo_resolver
+@foo_ifunc = ifunc void (), void ()* ()* @foo_resolver
 
-define i8* @foo_resolver() {
+define void ()* @foo_resolver() {
 entry:
-  ret i8* null
+  ret void ()* null
 }
 
 ; Function referencing ifunc.
 define void @bar() {
 entry:
   call void @foo_ifunc()
   ret void
 }
 
 ; Global referencing function.
 @ptr_bar = global void ()* @bar
 
 ; Alias for function.
 @alias_bar = alias void (), void ()* @bar
 
-@bar_ifunc = ifunc void (), i8* ()* @bar2_ifunc
-@bar2_ifunc = ifunc i8* (), i8* ()* @bar_resolver
+@bar_ifunc = ifunc void (), void ()* ()* @bar_resolver
 
-define i8* @bar_resolver() {
+define void ()* @bar_resolver() {
 entry:
-  ret i8* null
+  ret void ()* null
 }
 
 ; Function referencing bar.
 define void @bar2() {
 entry:
   call void @bar()
   ret void
 }

llvm/test/Bindings/llvm-c/echo.ll

 @nullptr = global i32* null
 
 @aliased1 = alias i32, i32* @var
 @aliased2 = internal alias i32, i32* @var
 @aliased3 = external alias i32, i32* @var
 @aliased4 = weak alias i32, i32* @var
 @aliased5 = weak_odr alias i32, i32* @var
 
-@ifunc = ifunc i32 (i32), i64 ()* @ifunc_resolver
+@ifunc = ifunc i32 (i32), i32 (i32)* ()* @ifunc_resolver
 
-define i64 @ifunc_resolver() {
+define i32 (i32)* @ifunc_resolver() {
 entry:
-  ret i64 0
+  ret i32 (i32)* null
 }
 
 define { i64, %S* } @unpackrepack(%S %s) {
   %1 = extractvalue %S %s, 0
   %2 = extractvalue %S %s, 1
   %3 = insertvalue { i64, %S* } undef, %S* %2, 1
   %4 = insertvalue { i64, %S* } %3, i64 %1, 0
   ret { i64, %S* } %4

llvm/test/Bitcode/compatibility-6.0.ll

 @a.local_unnamed_addr = local_unnamed_addr alias i32, i32* @g.local_unnamed_addr
 ; CHECK: @a.local_unnamed_addr = local_unnamed_addr alias i32, i32* @g.local_unnamed_addr
 
 ;; IFunc
 ; Format @<Name> = [Linkage] [Visibility] ifunc <IFuncTy>,
 ;                  <ResolverTy>* @<Resolver>
 
 ; IFunc -- Linkage
[e-mail] = external ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.external = ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = private ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.private = private ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = internal ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.internal = internal ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = external ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.external = ifunc void (), void ()* ()* @ifunc_resolver
[e-mail] = private ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.private = private ifunc void (), void ()* ()* @ifunc_resolver
[e-mail] = internal ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.internal = internal ifunc void (), void ()* ()* @ifunc_resolver
 
 ; IFunc -- Visibility
[e-mail] = default ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.default = ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = hidden ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.hidden = hidden ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = protected ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.protected = protected ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = default ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.default = ifunc void (), void ()* ()* @ifunc_resolver
[e-mail] = hidden ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.hidden = hidden ifunc void (), void ()* ()* @ifunc_resolver
[e-mail] = protected ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.protected = protected ifunc void (), void ()* ()* @ifunc_resolver
 
-define i8* @ifunc_resolver() {
+define void ()* @ifunc_resolver() {
 entry:
-  ret i8* null
+  ret void ()* null
 }
 
 ;; Functions
 ; Format: define [linkage] [visibility] [DLLStorageClass]
 ;         [cconv] [ret attrs]
 ;         <ResultType> @<FunctionName> ([argument list])
 ;         [(unnamed_addr|local_unnamed_addr)] [fn Attrs] [section "name"] [comdat [($name)]]
 ;         [align N] [gc] [prefix Constant] [prologue Constant]

llvm/test/Bitcode/compatibility.ll

 ; CHECK: @alias.partition = alias i32, i32* @g.partition, partition "part"
 @alias.partition = alias i32, i32* @g.partition, partition "part"
 
 ;; IFunc
 ; Format @<Name> = [Linkage] [Visibility] ifunc <IFuncTy>,
 ;                  <ResolverTy>* @<Resolver>
 
 ; IFunc -- Linkage
[e-mail] = external ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.external = ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = private ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.private = private ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = internal ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.internal = internal ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = external ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.external = ifunc void (), void ()* ()* @ifunc_resolver
[e-mail] = private ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.private = private ifunc void (), void ()* ()* @ifunc_resolver
[e-mail] = internal ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.internal = internal ifunc void (), void ()* ()* @ifunc_resolver
 
 ; IFunc -- Visibility
[e-mail] = default ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.default = ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = hidden ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.hidden = hidden ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = protected ifunc void (), i8* ()* @ifunc_resolver
-; CHECK: @ifunc.protected = protected ifunc void (), i8* ()* @ifunc_resolver
[e-mail] = default ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.default = ifunc void (), void ()* ()* @ifunc_resolver
[e-mail] = hidden ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.hidden = hidden ifunc void (), void ()* ()* @ifunc_resolver
[e-mail] = protected ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK: @ifunc.protected = protected ifunc void (), void ()* ()* @ifunc_resolver
 
 ; IFunc -- partition
-; CHECK: @ifunc.partition = ifunc void (), i8* ()* @ifunc_resolver, partition "part"
[e-mail] = ifunc void (), i8* ()* @ifunc_resolver, partition "part"
+; CHECK: @ifunc.partition = ifunc void (), void ()* ()* @ifunc_resolver, partition "part"
[e-mail] = ifunc void (), void ()* ()* @ifunc_resolver, partition "part"
 
-define i8* @ifunc_resolver() {
+define void ()* @ifunc_resolver() {
 entry:
-  ret i8* null
+  ret void ()* null
 }
 
 ;; Functions
 ; Format: define [linkage] [visibility] [DLLStorageClass]
 ;         [cconv] [ret attrs]
 ;         <ResultType> @<FunctionName> ([argument list])
 ;         [(unnamed_addr|local_unnamed_addr)] [fn Attrs] [section "name"] [comdat [($name)]]
 ;         [align N] [gc] [prefix Constant] [prologue Constant]

llvm/test/Bitcode/dso_local_equivalent.ll

 }
 
 define void @call_dso_local_alias_func() {
 ; CHECK: call void dso_local_equivalent @dso_local_alias_func()
   call void dso_local_equivalent @dso_local_alias_func()
   ret void
 }
 
-@ifunc_func = ifunc void (), i64 ()* @resolver
-@dso_local_ifunc_func = dso_local ifunc void (), i64 ()* @resolver
+@ifunc_func = ifunc void (), void ()* ()* @resolver
+@dso_local_ifunc_func = dso_local ifunc void (), void ()* ()* @resolver
 
-define internal i64 @resolver() {
+define internal void ()* @resolver() {
 entry:
-  ret i64 0
+  ret void ()* null
 }
 
 define void @call_ifunc_func() {
 ; CHECK: call void dso_local_equivalent @ifunc_func()
   call void dso_local_equivalent @ifunc_func()
   ret void
 }
 
 define void @call_dso_local_ifunc_func() {
 ; CHECK: call void dso_local_equivalent @dso_local_ifunc_func()
   call void dso_local_equivalent @dso_local_ifunc_func()
   ret void
 }

llvm/test/Bitcode/dso_location.ll

 ; CHECK: @protected_local_global = protected global i32 0
 
 @local_alias = dso_local alias i32, i32* @local_global
 ; CHECK-DAG: @local_alias = dso_local alias i32, i32* @local_global
 
 @preemptable_alias = dso_preemptable alias i32, i32* @hidden_local_global
 ; CHECK-DAG: @preemptable_alias = alias i32, i32* @hidden_local_global
 
-@preemptable_ifunc = dso_preemptable ifunc void (), i8* ()* @ifunc_resolver
-; CHECK-DAG: @preemptable_ifunc = ifunc void (), i8* ()* @ifunc_resolver
+@preemptable_ifunc = dso_preemptable ifunc void (), void ()* ()* @ifunc_resolver
+; CHECK-DAG: @preemptable_ifunc = ifunc void (), void ()* ()* @ifunc_resolver
 declare dso_local default void @default_local()
 ; CHECK: declare dso_local void @default_local()
 
 declare hidden void @hidden_local()
 ; CHECK: declare hidden void @hidden_local()
 
 define protected void @protected_local() {
 ; CHECK: define protected void @protected_local()
 entry:
   ret void
 }
 
-define i8* @ifunc_resolver() {
+define void ()* @ifunc_resolver() {
 entry:
-  ret i8* null
+  ret void ()* null
 }

llvm/test/CodeGen/X86/addrsig.ll

 ; RUN: llc < %s -mtriple=x86_64-unknown-linux | FileCheck --check-prefix=NO-ADDRSIG %s
 ; RUN: llc < %s -mtriple=x86_64-unknown-linux -addrsig | FileCheck %s
 
 ; NO-ADDRSIG-NOT: .addrsig
 
 ; CHECK: .addrsig
 
 ; CHECK: .addrsig_sym f1
-define void @f1() {
-  %f1 = bitcast void()* @f1 to i8*
-  %f2 = bitcast void()* @f2 to i8*
+define void()* @f1() {
+  %f1 = bitcast void()* ()* @f1 to i8*
+  %f2 = bitcast void()* ()* @f2 to i8*
   %f3 = bitcast void()* @f3 to i8*
   %g1 = bitcast i32* @g1 to i8*
   %g2 = bitcast i32* @g2 to i8*
   %g3 = bitcast i32* @g3 to i8*
   %dllimport = bitcast i32* @dllimport to i8*
   %tls = bitcast i32* @tls to i8*
   %a1 = bitcast i32* @a1 to i8*
   %a2 = bitcast i32* @a2 to i8*

 
 ; CHECK-NOT: .addrsig_sym metadata_f1
 declare void @metadata_f1()
 
 ; CHECK: .addrsig_sym metadata_f2
 declare void @metadata_f2()
 
 ; CHECK-NOT: .addrsig_sym f2
-define internal void @f2() local_unnamed_addr {
+define internal void()* @f2() local_unnamed_addr {
   unreachable
 }
 
 ; CHECK-NOT: .addrsig_sym f3
 declare void @f3() unnamed_addr
 
 ; CHECK: .addrsig_sym g1
 @g1 = global i32 0

 @tls = thread_local global i32 0
 
 ; CHECK: .addrsig_sym a1
 @a1 = alias i32, i32* @g1
 ; CHECK-NOT: .addrsig_sym a2
 @a2 = internal local_unnamed_addr alias i32, i32* @g2
 
 ; CHECK: .addrsig_sym i1
-@i1 = ifunc void(), void()* @f1
+@i1 = ifunc void(), void()* ()* @f1
 ; CHECK-NOT: .addrsig_sym i2
-@i2 = internal local_unnamed_addr ifunc void(), void()* @f2
+@i2 = internal local_unnamed_addr ifunc void(), void()* ()* @f2
 
 declare void @llvm.dbg.value(metadata, metadata, metadata)
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!2}
 
 !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug)
 !1 = !DIFile(filename: "a", directory: "")
 !2 = !{i32 2, !"Debug Info Version", i32 3}
 !3 = distinct !DISubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false, unit: !0)
 !4 = !DILocation(line: 0, scope: !3)
 !5 = !DILocalVariable(scope: !6)
 !6 = distinct !DISubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false, unit: !0)
 !7 = !DILocation(line: 0, scope: !6, inlinedAt: !4)

llvm/test/CodeGen/X86/dso_local_equivalent.ll

 
 ; CHECK: call_dso_local_alias_func:
 ; CHECK:   callq .Ldso_local_alias_func$local{{$}}
 define void @call_dso_local_alias_func() {
   call void dso_local_equivalent @dso_local_alias_func()
   ret void
 }
 
-@ifunc_func = ifunc void (), i64 ()* @resolver
-@dso_local_ifunc_func = dso_local ifunc void (), i64 ()* @resolver
+@ifunc_func = ifunc void (), void ()* ()* @resolver
+@dso_local_ifunc_func = dso_local ifunc void (), void ()* ()* @resolver
 
-define internal i64 @resolver() {
+define internal void ()* @resolver() {
 entry:
-  ret i64 0
+  ret void ()* null
 }
 
 ; If an ifunc is not dso_local already, then we should still emit a stub for it
 ; to ensure it will be dso_local.
 ; CHECK: call_ifunc_func:
 ; CHECK:   callq ifunc_func@PLT
 define void @call_ifunc_func() {
   call void dso_local_equivalent @ifunc_func()

llvm/test/CodeGen/X86/ifunc-asm.ll

 ; RUN: llvm-as < %s -o - | llc -filetype=asm | FileCheck %s
 
 target triple = "x86_64-unknown-linux-gnu"
 
-define internal i64 @foo_ifunc() {
+define internal i32 (i32)* @foo_ifunc() {
 entry:
-  ret i64 0
+  ret i32 (i32)* null
 }
 ; CHECK: .type foo_ifunc,@function
 ; CHECK-NEXT: foo_ifunc:
 
-@foo = ifunc i32 (i32), i64 ()* @foo_ifunc
+@foo = ifunc i32 (i32), i32 (i32)* ()* @foo_ifunc
 ; CHECK:      .type foo,@gnu_indirect_function
 ; CHECK-NEXT: .set foo, foo_ifunc

llvm/test/CodeGen/X86/partition.ll

 ; CHECK-NEXT: .ascii "part5"
 ; CHECK-NEXT: .zero 1
 ; CHECK-NEXT: .quad a1
 ; CHECK-NEXT: .section .llvm_sympart,"",@llvm_sympart,unique,4
 ; CHECK-NEXT: .ascii "part6"
 ; CHECK-NEXT: .zero 1
 ; CHECK-NEXT: .quad i1
 
-define void @f1() partition "part1" {
+define void ()* @f1() partition "part1" {
   unreachable
 }
 
 define hidden void @f2() partition "part2" {
   unreachable
 }
 
 declare void @f3() partition "part3"
 
 @g1 = global i32 0, partition "part4"
 
 @a1 = alias i32, i32* @g1, partition "part5"
-@i1 = ifunc void(), void()* @f1, partition "part6"
+@i1 = ifunc void(), void()* ()* @f1, partition "part6"

llvm/test/LTO/Resolution/X86/Inputs/ifunc2.ll

 target datalayout = "e-p:64:64"
 target triple = "x86_64-unknown-linux-gnu"
 
-define i32 @foo_resolver() {
-  ret i32 2
+define i32 ()* @foo_resolver() {
+  ret i32 ()* inttoptr (i32 2 to i32 ()*)
 }

llvm/test/LTO/Resolution/X86/ifunc.ll

 ; RUN: opt -module-summary -o %t.bc %s
-; RUN: llvm-lto2 run %t.bc -r %t.bc,foo,pl -r %t.bc,strlen,pl -o %t2
+; RUN: llvm-lto2 run %t.bc -r %t.bc,foo,pl -o %t2
 ; RUN: llvm-nm %t2.1 | FileCheck %s
 ; CHECK: i foo
 ; CHECK: t foo_resolver
-; CHECK: i strlen
-; CHECK: t strlen_resolver
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
-@foo = ifunc i32 (i32), i64 ()* @foo_resolver
-@strlen = ifunc i64 (i8*), bitcast (i64 (i8*)* ()* @strlen_resolver to i64 (i8*)*)
+@foo = ifunc i32 (i32), i32 (i32)* ()* @foo_resolver
 
-define internal i64 @foo_resolver() {
+define internal i32 (i32)* @foo_resolver() {
 entry:
-  ret i64 0
-}
-
-define internal i64 (i8*)* @strlen_resolver() {
-entry:
-  ret i64 (i8*)* null
+  ret i32 (i32)* null
 }

llvm/test/LTO/Resolution/X86/ifunc2.ll

 ; RUN: llvm-as -o %t1.o %s
 ; RUN: llvm-as -o %t2.o %S/Inputs/ifunc2.ll
 ; RUN: llvm-lto2 run %t1.o %t2.o -r %t1.o,foo,p -r %t1.o,foo_resolver, -r %t2.o,foo_resolver,p -save-temps -o %t3.o
 ; RUN: llvm-dis -o - %t3.o.0.0.preopt.bc | FileCheck %s
 
 target datalayout = "e-p:64:64"
 target triple = "x86_64-unknown-linux-gnu"
 
-; CHECK: @foo = ifunc i32 (), i32 ()* @foo_resolver.2
-@foo = ifunc i32 (), i32 ()* @foo_resolver
+; CHECK: @foo = ifunc i32 (), i32 ()* ()* @foo_resolver.2
+@foo = ifunc i32 (), i32 ()* ()* @foo_resolver
 
-; CHECK: define internal i32 @foo_resolver.2() {
-; CHECK-NEXT: ret i32 1
-define weak i32 @foo_resolver() {
-  ret i32 1
+; CHECK: define internal i32 ()* @foo_resolver.2() {
+; CHECK-NEXT: ret i32 ()* inttoptr (i32 1 to i32 ()*)
+define weak i32 ()* @foo_resolver() {
+  ret i32 ()* inttoptr (i32 1 to i32 ()*)
 }
 
-; CHECK: define i32 @foo_resolver() {
-; CHECK-NEXT: ret i32 2
+; CHECK: define i32 ()* @foo_resolver() {
+; CHECK-NEXT: ret i32 ()* inttoptr (i32 2 to i32 ()*)

llvm/test/Linker/ifunc.ll

 ; RUN: split-file %s %t
 ; RUN: llvm-link %t/a.ll %t/b.ll -S -o - | FileCheck %s
 
 ;; Check that ifuncs are linked in properly.
 
-; CHECK-DAG: @foo = ifunc void (), bitcast (void ()* ()* @foo_resolve to void ()*)
+; CHECK-DAG: @foo = ifunc void (), void ()* ()* @foo_resolve
 ; CHECK-DAG: define internal void ()* @foo_resolve() {
 
-; CHECK-DAG: @bar = ifunc void (), bitcast (void ()* ()* @bar_resolve to void ()*)
+; CHECK-DAG: @bar = ifunc void (), void ()* ()* @bar_resolve
 ; CHECK-DAG: define internal void ()* @bar_resolve() {
 
 ;--- a.ll
 declare void @bar()
 
 ;--- b.ll
-@foo = ifunc void (), bitcast (void ()* ()* @foo_resolve to void ()*)
-@bar = ifunc void (), bitcast (void ()* ()* @bar_resolve to void ()*)
+@foo = ifunc void (), void ()* ()* @foo_resolve
+@bar = ifunc void (), void ()* ()* @bar_resolve
 
 define internal void ()* @foo_resolve() {
   ret void ()* null
 }
 
 define internal void ()* @bar_resolve() {
   ret void ()* null
 }

llvm/test/Object/X86/nm-ir.ll

 @g1 = global i32 42
 @g2 = internal global i32 42
 @g3 = common global i32 0
 @g4 = private global i32 42
 
 @a1 = alias i32, i32* @g1
 @a2 = internal alias i32, i32* @g1
 
-define void @f1() {
+define void ()* @f1() {
   call void @f5()
-  ret void
+  ret void ()* null
 }
 
-@ifunc_f1 = ifunc void (), void ()* @f1
+@ifunc_f1 = ifunc void (), void ()* ()* @f1
 
 define internal void @f2() {
   ret void
 }
 
 define linkonce_odr void @f3() {
   ret void
 }
 
 declare void @f4()
 
 declare extern_weak void @f5()

llvm/test/ThinLTO/X86/empty-module.ll

 ; RUN: opt -module-summary -o %t.bc %s
 
 ; RUN: rm -f %t2.*
 ; RUN: llvm-lto2 run %t.bc -r %t.bc,foo,pl -o %t2 -thinlto-distributed-indexes -save-temps
 ; Ensure lto does not emit empty combined module.
 ; RUN: test ! -e %t2.0
 ; Ensure empty combined module has only 2 temp files.
 ; RUN: ls %t2.0.*.bc | count 2
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
-@foo = ifunc i32 (i32), i64 ()* @foo_ifunc
+@foo = ifunc i32 (i32), i32 (i32)* ()* @foo_ifunc
 
-define internal i64 @foo_ifunc() {
+define internal i32 (i32)* @foo_ifunc() {
 entry:
-  ret i64 0
+  ret i32 (i32)* null
 }

llvm/test/Transforms/GlobalDCE/global-ifunc.ll

 ; RUN: opt -S -globaldce < %s | FileCheck %s
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
-@if = ifunc void (), void ()* @fn
+@if = ifunc void (), void ()* ()* @fn
 
-define internal void @fn() {
+define internal void ()* @fn() {
 entry:
-  ret void
+  ret void ()* null
 }
 
-; CHECK-DAG: @if = ifunc void (), void ()* @fn
-; CHECK-DAG: define internal void @fn(
+; CHECK-DAG: @if = ifunc void (), void ()* ()* @fn
+; CHECK-DAG: define internal void ()* @fn(