[llvm-branch-commits] [llvm] 60bbb99 - [𝘀𝗽𝗿] initial version

Jon Roelofs via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Tue Nov 28 10:40:01 PST 2023


Author: Jon Roelofs
Date: 2023-11-28T10:39:54-08:00
New Revision: 60bbb996f2e9251b288e2230c671cdcf997720ed

URL: https://github.com/llvm/llvm-project/commit/60bbb996f2e9251b288e2230c671cdcf997720ed
DIFF: https://github.com/llvm/llvm-project/commit/60bbb996f2e9251b288e2230c671cdcf997720ed.diff

LOG: [𝘀𝗽𝗿] initial version

Created using spr 1.3.4

Added: 
    llvm/test/CodeGen/AArch64/GlobalISel/call-lowering-ifunc.ll
    llvm/test/CodeGen/AArch64/ifunc-asm.ll
    llvm/test/Verifier/ifunc-macho.ll

Modified: 
    clang/include/clang/Basic/Attr.td
    clang/include/clang/Basic/AttrDocs.td
    clang/include/clang/Basic/TargetInfo.h
    clang/test/CodeGen/attr-target-mv-va-args.c
    clang/test/CodeGen/ifunc.c
    llvm/docs/LangRef.rst
    llvm/include/llvm/CodeGen/AsmPrinter.h
    llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
    llvm/lib/IR/Verifier.cpp
    llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
    llvm/lib/Target/X86/X86AsmPrinter.cpp
    llvm/lib/Target/X86/X86AsmPrinter.h
    llvm/test/CodeGen/AArch64/addrsig-macho.ll
    llvm/test/CodeGen/X86/ifunc-asm.ll

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 03ed6accf700c4e..cef9f5578fa2baa 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -455,6 +455,9 @@ def TargetMicrosoftCXXABI : TargetArch<["x86", "x86_64", "arm", "thumb", "aarch6
 def TargetELF : TargetSpec {
   let ObjectFormats = ["ELF"];
 }
+def TargetELFOrMachO : TargetSpec {
+  let ObjectFormats = ["ELF", "MachO"];
+}
 
 def TargetSupportsInitPriority : TargetSpec {
   let CustomCode = [{ !Target.getTriple().isOSzOS() }];
@@ -1665,7 +1668,7 @@ def IBOutletCollection : InheritableAttr {
   let Documentation = [Undocumented];
 }
 
-def IFunc : Attr, TargetSpecificAttr<TargetELF> {
+def IFunc : Attr, TargetSpecificAttr<TargetELFOrMachO> {
   let Spellings = [GCC<"ifunc">];
   let Args = [StringArgument<"Resolver">];
   let Subjects = SubjectList<[Function]>;

diff  --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index be74535e28d8a60..4c4c4eb606fb0dc 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -5408,7 +5408,9 @@ considered inline.
 Not all targets support this attribute. ELF target support depends on both the
 linker and runtime linker, and is available in at least lld 4.0 and later,
 binutils 2.20.1 and later, glibc v2.11.1 and later, and FreeBSD 9.1 and later.
-Non-ELF targets currently do not support this attribute.
+MachO targets support it, but with slightly 
diff erent semantics: the resolver is
+run at first call, instead of at load time by the runtime linker. Targets other
+than ELF and MachO currently do not support this attribute.
   }];
 }
 

diff  --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
index 41f3c2e403cbef6..1fe2a18cd5dc9cc 100644
--- a/clang/include/clang/Basic/TargetInfo.h
+++ b/clang/include/clang/Basic/TargetInfo.h
@@ -1424,6 +1424,8 @@ class TargetInfo : public TransferrableTargetInfo,
 
   /// Identify whether this target supports IFuncs.
   bool supportsIFunc() const {
+    if (getTriple().isOSBinFormatMachO())
+      return true;
     return getTriple().isOSBinFormatELF() &&
            ((getTriple().isOSLinux() && !getTriple().isMusl()) ||
             getTriple().isOSFreeBSD());

diff  --git a/clang/test/CodeGen/attr-target-mv-va-args.c b/clang/test/CodeGen/attr-target-mv-va-args.c
index 96821c610235bdc..dbf5a74205c4c19 100644
--- a/clang/test/CodeGen/attr-target-mv-va-args.c
+++ b/clang/test/CodeGen/attr-target-mv-va-args.c
@@ -3,6 +3,7 @@
 // RUN: %clang_cc1 -triple x86_64-windows-pc -emit-llvm %s -o - | FileCheck %s --check-prefixes=NO-IFUNC,WINDOWS
 // RUN: %clang_cc1 -triple x86_64-linux-musl -emit-llvm %s -o - | FileCheck %s --check-prefixes=NO-IFUNC,NO-IFUNC-ELF
 // RUN: %clang_cc1 -triple x86_64-fuchsia -emit-llvm %s -o - | FileCheck %s --check-prefixes=NO-IFUNC,NO-IFUNC-ELF
+// RUN: %clang_cc1 -triple x86_64-apple-macho -emit-llvm %s -o - | FileCheck %s --check-prefix=IFUNC-MACHO
 int __attribute__((target("sse4.2"))) foo(int i, ...) { return 0; }
 int __attribute__((target("arch=sandybridge"))) foo(int i, ...);
 int __attribute__((target("arch=ivybridge"))) foo(int i, ...) {return 1;}
@@ -30,6 +31,24 @@ int bar(void) {
 // IFUNC-ELF: ret ptr @foo
 // IFUNC-ELF: declare i32 @foo.arch_sandybridge(i32 noundef, ...)
 
+// IFUNC-MACHO: @foo.ifunc = weak_odr ifunc i32 (i32, ...), ptr @foo.resolver
+// IFUNC-MACHO: define{{.*}} i32 @foo.sse4.2(i32 noundef %i, ...)
+// IFUNC-MACHO: ret i32 0
+// IFUNC-MACHO: define{{.*}} i32 @foo.arch_ivybridge(i32 noundef %i, ...)
+// IFUNC-MACHO: ret i32 1
+// IFUNC-MACHO: define{{.*}} i32 @foo(i32 noundef %i, ...)
+// IFUNC-MACHO: ret i32 2
+// IFUNC-MACHO: define{{.*}} i32 @bar()
+// IFUNC-MACHO: call i32 (i32, ...) @foo.ifunc(i32 noundef 1, i32 noundef 97, double
+// IFUNC-MACHO: call i32 (i32, ...) @foo.ifunc(i32 noundef 2, double noundef 2.2{{[0-9Ee+]+}}, ptr noundef
+
+// IFUNC-MACHO: define weak_odr ptr @foo.resolver()
+// IFUNC-MACHO: ret ptr @foo.arch_sandybridge
+// IFUNC-MACHO: ret ptr @foo.arch_ivybridge
+// IFUNC-MACHO: ret ptr @foo.sse4.2
+// IFUNC-MACHO: ret ptr @foo
+// IFUNC-MACHO: declare i32 @foo.arch_sandybridge(i32 noundef, ...)
+
 // NO-IFUNC: define dso_local i32 @foo.sse4.2(i32 noundef %i, ...)
 // NO-IFUNC: ret i32 0
 // NO-IFUNC: define dso_local i32 @foo.arch_ivybridge(i32 noundef %i, ...)

diff  --git a/clang/test/CodeGen/ifunc.c b/clang/test/CodeGen/ifunc.c
index 0b0a0549620f8b8..99d60dc0ea85dbd 100644
--- a/clang/test/CodeGen/ifunc.c
+++ b/clang/test/CodeGen/ifunc.c
@@ -3,6 +3,10 @@
 // RUN: %clang_cc1 -triple i386-unknown-linux-gnu -fsanitize=thread -O2 -emit-llvm -o - %s | FileCheck %s --check-prefix=SAN
 // RUN: %clang_cc1 -triple i386-unknown-linux-gnu -fsanitize=address -O2 -emit-llvm -o - %s | FileCheck %s --check-prefix=SAN
 // RUN: %clang_cc1 -triple i386-unknown-linux-gnu -fsanitize=memory -O2 -emit-llvm -o - %s | FileCheck %s --check-prefix=SAN
+// RUN: %clang_cc1 -triple x86_64-apple-macosx -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-apple-macosx -O2 -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-apple-macosx -fsanitize=thread -O2 -emit-llvm -o - %s | FileCheck %s --check-prefix=MACSAN
+// RUN: %clang_cc1 -triple x86_64-apple-macosx -fsanitize=address -O2 -emit-llvm -o - %s | FileCheck %s --check-prefix=MACSAN
 
 int foo(int) __attribute__ ((ifunc("foo_ifunc")));
 
@@ -44,9 +48,13 @@ void* goo_ifunc(void) {
 // CHECK: call void @goo()
 
 // SAN: define internal nonnull ptr @foo_ifunc() #[[#FOO_IFUNC:]] {
+// MACSAN: define internal nonnull ptr @foo_ifunc() #[[#FOO_IFUNC:]] {
 
 // SAN: define dso_local noalias ptr @goo_ifunc() #[[#GOO_IFUNC:]] {
+// MACSAN: define noalias ptr @goo_ifunc() #[[#GOO_IFUNC:]] {
 
 // SAN-DAG: attributes #[[#FOO_IFUNC]] = {{{.*}} disable_sanitizer_instrumentation {{.*}}
+// MACSAN-DAG: attributes #[[#FOO_IFUNC]] = {{{.*}} disable_sanitizer_instrumentation {{.*}}
 
 // SAN-DAG: attributes #[[#GOO_IFUNC]] = {{{.*}} disable_sanitizer_instrumentation {{.*}}
+// MACSAN-DAG: attributes #[[#GOO_IFUNC]] = {{{.*}} disable_sanitizer_instrumentation {{.*}}

diff  --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index e448c5ed5c5d947..cb222e979db29d4 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -934,10 +934,11 @@ IFuncs
 -------
 
 IFuncs, like as aliases, don't create any new data or func. They are just a new
-symbol that dynamic linker resolves at runtime by calling a resolver function.
+symbol that is resolved at runtime by calling a resolver function.
 
-IFuncs have a name and a resolver that is a function called by dynamic linker
-that returns address of another function associated with the name.
+On ELF platforms, IFuncs are resolved by the dynamic linker at load time. On
+MachO platforms, they are lowered in terms of ``.symbol_resolver``s, which
+lazily resolve the callee the first time they are called.
 
 IFunc may have an optional :ref:`linkage type <linkage>` and an optional
 :ref:`visibility style <visibility>`.

diff  --git a/llvm/include/llvm/CodeGen/AsmPrinter.h b/llvm/include/llvm/CodeGen/AsmPrinter.h
index 2731ef452c79cbb..48fa6c478464c73 100644
--- a/llvm/include/llvm/CodeGen/AsmPrinter.h
+++ b/llvm/include/llvm/CodeGen/AsmPrinter.h
@@ -882,7 +882,11 @@ class AsmPrinter : public MachineFunctionPass {
 
   GCMetadataPrinter *getOrCreateGCPrinter(GCStrategy &S);
   void emitGlobalAlias(Module &M, const GlobalAlias &GA);
-  void emitGlobalIFunc(Module &M, const GlobalIFunc &GI);
+
+protected:
+  virtual void emitGlobalIFunc(Module &M, const GlobalIFunc &GI);
+
+private:
 
   /// This method decides whether the specified basic block requires a label.
   bool shouldEmitLabelForBasicBlock(const MachineBasicBlock &MBB) const;

diff  --git a/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp b/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
index 2527b1431289677..e0080b145d4f995 100644
--- a/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CallLowering.cpp
@@ -144,7 +144,12 @@ bool CallLowering::lowerCall(MachineIRBuilder &MIRBuilder, const CallBase &CB,
   // Try looking through a bitcast from one function type to another.
   // Commonly happens with calls to objc_msgSend().
   const Value *CalleeV = CB.getCalledOperand()->stripPointerCasts();
-  if (const Function *F = dyn_cast<Function>(CalleeV))
+  if (const GlobalIFunc *IF = dyn_cast<GlobalIFunc>(CalleeV);
+      IF && MF.getTarget().getTargetTriple().isOSBinFormatMachO()) {
+    // ld64 requires that .symbol_resolvers to be called via a stub, so these
+    // must always be a diret call.
+    Info.Callee = MachineOperand::CreateGA(IF, 0);
+  } else if (const Function *F = dyn_cast<Function>(CalleeV))
     Info.Callee = MachineOperand::CreateGA(F, 0);
   else
     Info.Callee = MachineOperand::CreateReg(GetCalleeReg(), false);

diff  --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index 5560c037aa3ee6b..94e76a43bf38d6d 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -959,6 +959,7 @@ void Verifier::visitGlobalIFunc(const GlobalIFunc &GI) {
       GlobalIFunc::getResolverFunctionType(GI.getValueType());
   Check(ResolverTy == ResolverFuncTy->getPointerTo(GI.getAddressSpace()),
         "IFunc resolver has incorrect type", &GI);
+
 }
 
 void Verifier::visitNamedMDNode(const NamedMDNode &NMD) {
@@ -2239,13 +2240,10 @@ void Verifier::verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
   }
 
   // Check EVEX512 feature.
-  if (MaxParameterWidth >= 512 && Attrs.hasFnAttr("target-features")) {
-    Triple T(M.getTargetTriple());
-    if (T.isX86()) {
-      StringRef TF = Attrs.getFnAttr("target-features").getValueAsString();
-      Check(!TF.contains("+avx512f") || !TF.contains("-evex512"),
-            "512-bit vector arguments require 'evex512' for AVX512", V);
-    }
+  if (MaxParameterWidth >= 512 && Attrs.hasFnAttr("target-features") && TT.isX86()) {
+    StringRef TF = Attrs.getFnAttr("target-features").getValueAsString();
+    Check(!TF.contains("+avx512f") || !TF.contains("-evex512"),
+          "512-bit vector arguments require 'evex512' for AVX512", V);
   }
 
   checkUnsignedBaseTenFuncAttr(Attrs, "patchable-function-prefix", V);

diff  --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
index f4d3a85f34c88da..2dab8e126c9abd0 100644
--- a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -30,6 +30,7 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/BinaryFormat/COFF.h"
 #include "llvm/BinaryFormat/ELF.h"
+#include "llvm/BinaryFormat/MachO.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/FaultMaps.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
@@ -47,10 +48,12 @@
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCInstBuilder.h"
 #include "llvm/MC/MCSectionELF.h"
+#include "llvm/MC/MCSectionMachO.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetMachine.h"
@@ -68,6 +71,22 @@ using namespace llvm;
 
 namespace {
 
+enum class IFuncLowering { SymbolResolverIfSupported, SymbolResolverAlways, SymbolResolverNever };
+
+static cl::opt<IFuncLowering> PreferredIFuncLowering(
+    "arm64-darwin-ifunc-symbol_resolver", cl::init(IFuncLowering::SymbolResolverNever),
+    cl::desc("Pick the lowering for ifuncs on darwin platforms"), cl::Hidden,
+    cl::values(
+        clEnumValN(
+            IFuncLowering::SymbolResolverIfSupported, "if_supported",
+            "Use .symbol_resolver's when known to be supported by the linker."),
+        clEnumValN(IFuncLowering::SymbolResolverAlways, "always",
+                   "Always use .symbol_resolvers. NOTE: this might not be "
+                   "supported by the linker in all cases."),
+        clEnumValN(IFuncLowering::SymbolResolverNever, "never",
+                   "Use a manual lowering, doing what the linker would have "
+                   "done, but in the compiler.")));
+
 class AArch64AsmPrinter : public AsmPrinter {
   AArch64MCInstLower MCInstLowering;
   FaultMaps FM;
@@ -198,6 +217,11 @@ class AArch64AsmPrinter : public AsmPrinter {
   bool shouldEmitWeakSwiftAsyncExtendedFramePointerFlags() const override {
     return ShouldEmitWeakSwiftAsyncExtendedFramePointerFlags;
   }
+
+  void emitGlobalIFunc(Module &M, const GlobalIFunc &GI) override;
+
+  void emitLinkerSymbolResolver(Module &M, const GlobalIFunc &GI);
+  void emitManualSymbolResolver(Module &M, const GlobalIFunc &GI);
 };
 
 } // end anonymous namespace
@@ -1809,6 +1833,290 @@ void AArch64AsmPrinter::emitInstruction(const MachineInstr *MI) {
   EmitToStreamer(*OutStreamer, TmpInst);
 }
 
+void AArch64AsmPrinter::emitLinkerSymbolResolver(Module &M,
+                                                 const GlobalIFunc &GI) {
+  OutStreamer->switchSection(OutContext.getObjectFileInfo()->getTextSection());
+
+  MCSymbol *Name = getSymbol(&GI);
+
+  // NOTE: non-global .symbol_resolvers are not yet supported by Darwin linkers
+
+  if (GI.hasExternalLinkage() || !MAI->getWeakRefDirective())
+    OutStreamer->emitSymbolAttribute(Name, MCSA_Global);
+  else if (GI.hasWeakLinkage() || GI.hasLinkOnceLinkage())
+    OutStreamer->emitSymbolAttribute(Name, MCSA_WeakReference);
+  else
+    assert(GI.hasLocalLinkage() && "Invalid ifunc linkage");
+
+  OutStreamer->emitCodeAlignment(Align(4), STI);
+  OutStreamer->emitLabel(Name);
+  OutStreamer->emitSymbolAttribute(Name, MCSA_SymbolResolver);
+  emitVisibility(Name, GI.getVisibility());
+
+  // ld-prime does not seem to support aliases of symbol resolvers, so we have to
+  // tail call the resolver manually.
+  OutStreamer->emitInstruction(
+      MCInstBuilder(AArch64::B)
+          .addOperand(MCOperand::createExpr(lowerConstant(GI.getResolver()))),
+      *STI);
+}
+
+/// \brief Emit a manually-constructed .symbol_resolver that implements the
+/// symbol resolution duties of the IFunc.
+///
+/// Normally, this would be handled by linker magic, but unfortunately there are
+/// a few limitations in ld64 and ld-prime's implementation of .symbol_resolver
+/// that mean we can't always use them:
+///
+///    *  resolvers cannot be the target of an alias
+///    *  resolvers cannot have private linkage
+///    *  resolvers cannot have linkonce linkage
+///    *  resolvers cannot appear in executables
+///    *  resolvers cannot appear in bundles
+///
+/// This works around that by emitting a close approximation of what the linker
+/// would have done.
+void AArch64AsmPrinter::emitManualSymbolResolver(Module &M,
+                                                 const GlobalIFunc &GI) {
+  auto EmitLinkage = [&](MCSymbol *Sym) {
+    if (GI.hasExternalLinkage() || !MAI->getWeakRefDirective())
+      OutStreamer->emitSymbolAttribute(Sym, MCSA_Global);
+    else if (GI.hasWeakLinkage() || GI.hasLinkOnceLinkage())
+      OutStreamer->emitSymbolAttribute(Sym, MCSA_WeakReference);
+    else
+      assert(GI.hasLocalLinkage() && "Invalid ifunc linkage");
+  };
+
+  MCSymbol *LazyPointer = TM.getObjFileLowering()->getContext().getOrCreateSymbol(
+      "_" + GI.getName() + ".lazy_pointer");
+  MCSymbol *StubHelper =
+      TM.getObjFileLowering()->getContext().getOrCreateSymbol(
+          "_" + GI.getName() + ".stub_helper");
+
+  OutStreamer->switchSection(OutContext.getObjectFileInfo()->getDataSection());
+
+  EmitLinkage(LazyPointer);
+  OutStreamer->emitLabel(LazyPointer);
+  emitVisibility(LazyPointer, GI.getVisibility());
+  OutStreamer->emitValue(MCSymbolRefExpr::create(StubHelper, OutContext), 8);
+
+  OutStreamer->switchSection(OutContext.getObjectFileInfo()->getTextSection());
+
+  MCSymbol *Stub = getSymbol(&GI);
+
+  EmitLinkage(Stub);
+  OutStreamer->emitCodeAlignment(Align(4), STI);
+  OutStreamer->emitLabel(Stub);
+  emitVisibility(Stub, GI.getVisibility());
+
+  // adrp	x16, lazy_pointer at GOTPAGE
+  // ldr	x16, [x16, lazy_pointer at GOTPAGEOFF]
+  // ldr	x16, [x16]
+  // br	x16
+
+  {
+    MCInst Adrp;
+    Adrp.setOpcode(AArch64::ADRP);
+    Adrp.addOperand(MCOperand::createReg(AArch64::X16));
+    MCOperand SymPage;
+    MCInstLowering.lowerOperand(
+        MachineOperand::CreateES(LazyPointer->getName().data() + 1,
+                                 AArch64II::MO_GOT | AArch64II::MO_PAGE),
+        SymPage);
+    Adrp.addOperand(SymPage);
+    OutStreamer->emitInstruction(Adrp, *STI);
+  }
+
+  {
+    MCInst Ldr;
+    Ldr.setOpcode(AArch64::LDRXui);
+    Ldr.addOperand(MCOperand::createReg(AArch64::X16));
+    Ldr.addOperand(MCOperand::createReg(AArch64::X16));
+    MCOperand SymPageOff;
+    MCInstLowering.lowerOperand(
+        MachineOperand::CreateES(LazyPointer->getName().data() + 1,
+                                 AArch64II::MO_GOT | AArch64II::MO_PAGEOFF),
+        SymPageOff);
+    Ldr.addOperand(SymPageOff);
+    Ldr.addOperand(MCOperand::createImm(0));
+    OutStreamer->emitInstruction(Ldr, *STI);
+  }
+
+  OutStreamer->emitInstruction(MCInstBuilder(AArch64::LDRXui)
+    .addReg(AArch64::X16)
+    .addReg(AArch64::X16)
+    .addImm(0), *STI);
+
+  OutStreamer->emitInstruction(MCInstBuilder(TM.getTargetTriple().isArm64e()
+                                                 ? AArch64::BRAAZ
+                                                 : AArch64::BR)
+                                   .addReg(AArch64::X16),
+                               *STI);
+
+  EmitLinkage(StubHelper);
+  OutStreamer->emitCodeAlignment(Align(4), STI);
+  OutStreamer->emitLabel(StubHelper);
+  emitVisibility(StubHelper, GI.getVisibility());
+
+  // stp	fp, lr, [sp, #-16]!
+  // mov	fp, sp
+  // stp	x1, x0, [sp, #-16]!
+  // stp	x3, x2, [sp, #-16]!
+  // stp	x5, x4, [sp, #-16]!
+  // stp	x7, x6, [sp, #-16]!
+  // stp	d1, d0, [sp, #-16]!
+  // stp	d3, d2, [sp, #-16]!
+  // stp	d5, d4, [sp, #-16]!
+  // stp	d7, d6, [sp, #-16]!
+  // bl	_resolver
+  // adrp	x16, lazy_pointer at GOTPAGE
+  // ldr	x16, [x16, lazy_pointer at GOTPAGEOFF]
+  // str	x0, [x16]
+  // mov	x16, x0
+  // ldp	d7, d6, [sp], #16
+  // ldp	d5, d4, [sp], #16
+  // ldp	d3, d2, [sp], #16
+  // ldp	d1, d0, [sp], #16
+  // ldp	x7, x6, [sp], #16
+  // ldp	x5, x4, [sp], #16
+  // ldp	x3, x2, [sp], #16
+  // ldp	x1, x0, [sp], #16
+  // ldp	fp, lr, [sp], #16
+  // br	x16
+
+  OutStreamer->emitInstruction(MCInstBuilder(AArch64::STPXpre)
+                                   .addReg(AArch64::SP)
+                                   .addReg(AArch64::FP)
+                                   .addReg(AArch64::LR)
+                                   .addReg(AArch64::SP)
+                                   .addImm(-2),
+                               *STI);
+
+  OutStreamer->emitInstruction(MCInstBuilder(AArch64::ADDXri)
+                                   .addReg(AArch64::FP)
+                                   .addReg(AArch64::SP)
+                                   .addImm(0)
+                                   .addImm(0),
+                               *STI);
+
+  for (int I = 0; I != 4; ++I)
+    OutStreamer->emitInstruction(MCInstBuilder(AArch64::STPXpre)
+                                     .addReg(AArch64::SP)
+                                     .addReg(AArch64::X1 + 2 * I)
+                                     .addReg(AArch64::X0 + 2 * I)
+                                     .addReg(AArch64::SP)
+                                     .addImm(-2),
+                                 *STI);
+
+  for (int I = 0; I != 4; ++I)
+    OutStreamer->emitInstruction(MCInstBuilder(AArch64::STPDpre)
+                                     .addReg(AArch64::SP)
+                                     .addReg(AArch64::D1 + 2 * I)
+                                     .addReg(AArch64::D0 + 2 * I)
+                                     .addReg(AArch64::SP)
+                                     .addImm(-2),
+                                 *STI);
+
+  OutStreamer->emitInstruction(
+      MCInstBuilder(AArch64::BL)
+          .addOperand(MCOperand::createExpr(lowerConstant(GI.getResolver()))),
+      *STI);
+
+  {
+    MCInst Adrp;
+    Adrp.setOpcode(AArch64::ADRP);
+    Adrp.addOperand(MCOperand::createReg(AArch64::X16));
+    MCOperand SymPage;
+    MCInstLowering.lowerOperand(
+        MachineOperand::CreateES(LazyPointer->getName().data() + 1,
+                                 AArch64II::MO_GOT | AArch64II::MO_PAGE),
+        SymPage);
+    Adrp.addOperand(SymPage);
+    OutStreamer->emitInstruction(Adrp, *STI);
+  }
+
+  {
+    MCInst Ldr;
+    Ldr.setOpcode(AArch64::LDRXui);
+    Ldr.addOperand(MCOperand::createReg(AArch64::X16));
+    Ldr.addOperand(MCOperand::createReg(AArch64::X16));
+    MCOperand SymPageOff;
+    MCInstLowering.lowerOperand(
+        MachineOperand::CreateES(LazyPointer->getName().data() + 1,
+                                 AArch64II::MO_GOT | AArch64II::MO_PAGEOFF),
+        SymPageOff);
+    Ldr.addOperand(SymPageOff);
+    Ldr.addOperand(MCOperand::createImm(0));
+    OutStreamer->emitInstruction(Ldr, *STI);
+  }
+
+  OutStreamer->emitInstruction(MCInstBuilder(AArch64::STRXui)
+                                   .addReg(AArch64::X0)
+                                   .addReg(AArch64::X16)
+                                   .addImm(0),
+                               *STI);
+
+  OutStreamer->emitInstruction(MCInstBuilder(AArch64::ADDXri)
+                                   .addReg(AArch64::X16)
+                                   .addReg(AArch64::X0)
+                                   .addImm(0)
+                                   .addImm(0),
+                               *STI);
+
+  for (int I = 3; I != -1; --I)
+    OutStreamer->emitInstruction(MCInstBuilder(AArch64::LDPDpost)
+                                     .addReg(AArch64::SP)
+                                     .addReg(AArch64::D1 + 2 * I)
+                                     .addReg(AArch64::D0 + 2 * I)
+                                     .addReg(AArch64::SP)
+                                     .addImm(2),
+                                 *STI);
+
+  for (int I = 3; I != -1; --I)
+    OutStreamer->emitInstruction(MCInstBuilder(AArch64::LDPXpost)
+                                     .addReg(AArch64::SP)
+                                     .addReg(AArch64::X1 + 2 * I)
+                                     .addReg(AArch64::X0 + 2 * I)
+                                     .addReg(AArch64::SP)
+                                     .addImm(2),
+                                 *STI);
+
+  OutStreamer->emitInstruction(MCInstBuilder(AArch64::LDPXpost)
+                                   .addReg(AArch64::SP)
+                                   .addReg(AArch64::FP)
+                                   .addReg(AArch64::LR)
+                                   .addReg(AArch64::SP)
+                                   .addImm(2),
+                               *STI);
+
+  OutStreamer->emitInstruction(MCInstBuilder(TM.getTargetTriple().isArm64e()
+                                                 ? AArch64::BRAAZ
+                                                 : AArch64::BR)
+                                   .addReg(AArch64::X16),
+                               *STI);
+}
+
+void AArch64AsmPrinter::emitGlobalIFunc(Module &M, const GlobalIFunc &GI) {
+  if (!TM.getTargetTriple().isOSBinFormatMachO())
+    return AsmPrinter::emitGlobalIFunc(M, GI);
+
+  switch (PreferredIFuncLowering) {
+  case IFuncLowering::SymbolResolverAlways:
+    return emitLinkerSymbolResolver(M, GI);
+  case IFuncLowering::SymbolResolverNever:
+    return emitManualSymbolResolver(M, GI);
+  case IFuncLowering::SymbolResolverIfSupported:
+    if (GI.hasExternalLinkage() || !MAI->getWeakRefDirective())
+      return emitLinkerSymbolResolver(M, GI);
+    else if (GI.hasWeakLinkage() || GI.hasLinkOnceLinkage())
+      // NOTE: non-global .symbol_resolvers are not yet supported by Darwin
+      // linkers
+      return emitManualSymbolResolver(M, GI);
+    else
+      assert(GI.hasLocalLinkage() && "Invalid ifunc linkage");
+  }
+}
+
 // Force static initialization.
 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAArch64AsmPrinter() {
   RegisterAsmPrinter<AArch64AsmPrinter> X(getTheAArch64leTarget());

diff  --git a/llvm/lib/Target/X86/X86AsmPrinter.cpp b/llvm/lib/Target/X86/X86AsmPrinter.cpp
index 73c7450620966cd..5241aa6e1c0eade 100644
--- a/llvm/lib/Target/X86/X86AsmPrinter.cpp
+++ b/llvm/lib/Target/X86/X86AsmPrinter.cpp
@@ -530,6 +530,34 @@ void X86AsmPrinter::PrintIntelMemReference(const MachineInstr *MI,
   O << ']';
 }
 
+void X86AsmPrinter::emitGlobalIFunc(Module &M, const GlobalIFunc &GI) {
+  if (!TM.getTargetTriple().isOSBinFormatMachO())
+    return AsmPrinter::emitGlobalIFunc(M, GI);
+
+  OutStreamer->switchSection(OutContext.getObjectFileInfo()->getTextSection());
+
+  MCSymbol *Name = getSymbol(&GI);
+
+  if (GI.hasExternalLinkage() || !MAI->getWeakRefDirective())
+    OutStreamer->emitSymbolAttribute(Name, MCSA_Global);
+  else if (GI.hasWeakLinkage() || GI.hasLinkOnceLinkage())
+    OutStreamer->emitSymbolAttribute(Name, MCSA_WeakReference);
+  else
+    assert(GI.hasLocalLinkage() && "Invalid ifunc linkage");
+
+  OutStreamer->emitCodeAlignment(Align(16), Subtarget);
+  OutStreamer->emitLabel(Name);
+  OutStreamer->emitSymbolAttribute(Name, MCSA_SymbolResolver);
+  emitVisibility(Name, GI.getVisibility());
+
+  // ld64 does not seem to support aliases of symbol resolvers, so we have to
+  // tail call the resolver manually.
+  MCInst JMP;
+  JMP.setOpcode(X86::JMP_4);
+  JMP.addOperand(MCOperand::createExpr(lowerConstant(GI.getResolver())));
+  OutStreamer->emitInstruction(JMP, *Subtarget);
+}
+
 static bool printAsmMRegister(const X86AsmPrinter &P, const MachineOperand &MO,
                               char Mode, raw_ostream &O) {
   Register Reg = MO.getReg();

diff  --git a/llvm/lib/Target/X86/X86AsmPrinter.h b/llvm/lib/Target/X86/X86AsmPrinter.h
index c81651cf7f2f0e6..47f3b7c00c99ddb 100644
--- a/llvm/lib/Target/X86/X86AsmPrinter.h
+++ b/llvm/lib/Target/X86/X86AsmPrinter.h
@@ -120,6 +120,7 @@ class LLVM_LIBRARY_VISIBILITY X86AsmPrinter : public AsmPrinter {
                          const char *Modifier);
   void PrintIntelMemReference(const MachineInstr *MI, unsigned OpNo,
                               raw_ostream &O, const char *Modifier);
+  void emitGlobalIFunc(Module &M, const GlobalIFunc &GI) override;
 
 public:
   X86AsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer);

diff  --git a/llvm/test/CodeGen/AArch64/GlobalISel/call-lowering-ifunc.ll b/llvm/test/CodeGen/AArch64/GlobalISel/call-lowering-ifunc.ll
new file mode 100644
index 000000000000000..8e51845c2faa9c0
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/call-lowering-ifunc.ll
@@ -0,0 +1,37 @@
+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
+; RUN: llc -mtriple=aarch64-macho -global-isel -stop-after=irtranslator -verify-machineinstrs -o - %s | FileCheck %s --check-prefixes=MACHO,CHECK
+; RUN: llc -mtriple=aarch64-elf -global-isel -stop-after=irtranslator -verify-machineinstrs -o - %s | FileCheck %s --check-prefixes=ELF,CHECK
+
+ at foo_ifunc = ifunc i32 (i32), ptr @foo_resolver
+
+define internal ptr @foo_resolver() {
+  ; CHECK-LABEL: name: foo_resolver
+  ; CHECK: bb.1.entry:
+  ; CHECK-NEXT:   [[C:%[0-9]+]]:_(p0) = G_CONSTANT i64 0
+  ; CHECK-NEXT:   $x0 = COPY [[C]](p0)
+  ; CHECK-NEXT:   RET_ReallyLR implicit $x0
+entry:
+  ret ptr null
+}
+
+define void @caller() {
+  ; MACHO-LABEL: name: caller
+  ; MACHO: bb.1.entry:
+  ; MACHO-NEXT:   ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+  ; MACHO-NEXT:   BL @foo_ifunc, csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit-def $w0
+  ; MACHO-NEXT:   ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+  ; MACHO-NEXT:   [[COPY:%[0-9]+]]:_(s32) = COPY $w0
+  ; MACHO-NEXT:   RET_ReallyLR
+  ;
+  ; ELF-LABEL: name: caller
+  ; ELF: bb.1.entry:
+  ; ELF-NEXT:   [[GV:%[0-9]+]]:gpr64(p0) = G_GLOBAL_VALUE @foo_ifunc
+  ; ELF-NEXT:   ADJCALLSTACKDOWN 0, 0, implicit-def $sp, implicit $sp
+  ; ELF-NEXT:   BLR [[GV]](p0), csr_aarch64_aapcs, implicit-def $lr, implicit $sp, implicit-def $w0
+  ; ELF-NEXT:   ADJCALLSTACKUP 0, 0, implicit-def $sp, implicit $sp
+  ; ELF-NEXT:   [[COPY:%[0-9]+]]:_(s32) = COPY $w0
+  ; ELF-NEXT:   RET_ReallyLR
+entry:
+  %0 = call i32 @foo_ifunc()
+  ret void
+}

diff  --git a/llvm/test/CodeGen/AArch64/addrsig-macho.ll b/llvm/test/CodeGen/AArch64/addrsig-macho.ll
index 360876fccaad34e..980b0e7bc446695 100644
--- a/llvm/test/CodeGen/AArch64/addrsig-macho.ll
+++ b/llvm/test/CodeGen/AArch64/addrsig-macho.ll
@@ -118,8 +118,8 @@ declare void @f3() unnamed_addr
 @a1 = alias i32, i32* @g1
 @a2 = internal local_unnamed_addr alias i32, i32* @g2
 
- at i1 = ifunc void(), void()* ()* @f1
- at i2 = internal local_unnamed_addr ifunc void(), void()* ()* @f2
+ at i1 = external ifunc void(), void()* ()* @f1
+ at i2 = external local_unnamed_addr ifunc void(), void()* ()* @f2
 
 declare void @llvm.dbg.value(metadata, metadata, metadata)
 

diff  --git a/llvm/test/CodeGen/AArch64/ifunc-asm.ll b/llvm/test/CodeGen/AArch64/ifunc-asm.ll
new file mode 100644
index 000000000000000..fbc0f74cee46baa
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/ifunc-asm.ll
@@ -0,0 +1,82 @@
+; RUN: llc -mtriple=arm64-unknown-linux-gnu %s -filetype=asm -o - | FileCheck %s --check-prefixes=ELF
+; RUN: llc -mtriple=arm64-apple-darwin %s -filetype=asm -o - -arm64-darwin-ifunc-symbol_resolver=always | FileCheck %s --check-prefixes=MACHO,MACHO-LINKER
+; RUN: llc -mtriple=arm64-apple-darwin %s -filetype=asm -o - -arm64-darwin-ifunc-symbol_resolver=if_supported | FileCheck %s --check-prefixes=MACHO,MACHO-DEFAULT
+; RUN: llc -mtriple=arm64-apple-darwin %s -filetype=asm -o - -arm64-darwin-ifunc-symbol_resolver=never | FileCheck %s --check-prefixes=MACHO,MACHO-MANUAL
+; RUN: llc -mtriple=arm64-apple-darwin %s -filetype=asm -o - | FileCheck %s --check-prefixes=MACHO,MACHO-MANUAL
+
+define internal ptr @foo_resolver() {
+entry:
+  ret ptr null
+}
+; ELF:                    .type foo_resolver, at function
+; ELF-NEXT:           foo_resolver:
+
+; MACHO:                  .p2align 2
+; MACHO-NEXT:         _foo_resolver
+
+
+ at foo_ifunc = ifunc i32 (i32), ptr @foo_resolver
+; ELF:                    .globl foo_ifunc
+; ELF-NEXT:               .type foo_ifunc, at gnu_indirect_function
+; ELF-NEXT:               .set foo_ifunc, foo_resolver
+
+; MACHO-LINKER:           .globl _foo_ifunc
+; MACHO-LINKER-NEXT:      .p2align 2
+; MACHO-LINKER-NEXT:  _foo_ifunc:
+; MACHO-LINKER-NEXT:      .symbol_resolver _foo_ifunc
+; MACHO-LINKER-NEXT:      b _foo_resolver
+
+; MACHO-DEFAULT:          .globl _foo_ifunc
+; MACHO-DEFAULT-NEXT:     .p2align 2
+; MACHO-DEFAULT-NEXT: _foo_ifunc:
+; MACHO-DEFAULT-NEXT:     .symbol_resolver _foo_ifunc
+; MACHO-DEFAULT-NEXT:     b _foo_resolver
+
+; MACHO-MANUAL:           .section __DATA,__data
+; MACHO-MANUAL-NEXT:      .globl _foo_ifunc.lazy_pointer
+; MACHO-MANUAL-NEXT:  _foo_ifunc.lazy_pointer:
+; MACHO-MANUAL-NEXT:      .quad _foo_ifunc.stub_helper
+
+; MACHO-MANUAL:           .section __TEXT,__text,regular,pure_instructions
+; MACHO-MANUAL-NEXT:      .globl _foo_ifunc
+; MACHO-MANUAL-NEXT:      .p2align 2
+; MACHO-MANUAL-NEXT:  _foo_ifunc:
+; MACHO-MANUAL-NEXT:      adrp    x16, _foo_ifunc.lazy_pointer at GOTPAGE
+; MACHO-MANUAL-NEXT:      ldr     x16, [x16, _foo_ifunc.lazy_pointer at GOTPAGEOFF]
+; MACHO-MANUAL-NEXT:      ldr     x16, [x16]
+; MACHO-MANUAL-NEXT:      br      x16
+; MACHO-MANUAL-NEXT:      .globl  _foo_ifunc.stub_helper
+; MACHO-MANUAL-NEXT:      .p2align        2
+; MACHO-MANUAL-NEXT:  _foo_ifunc.stub_helper:
+; MACHO-MANUAL-NEXT:      stp     x29, x30, [sp, #-16]!
+; MACHO-MANUAL-NEXT:      mov     x29, sp
+; MACHO-MANUAL-NEXT:      stp     x1, x0, [sp, #-16]!
+; MACHO-MANUAL-NEXT:      stp     x3, x2, [sp, #-16]!
+; MACHO-MANUAL-NEXT:      stp     x5, x4, [sp, #-16]!
+; MACHO-MANUAL-NEXT:      stp     x7, x6, [sp, #-16]!
+; MACHO-MANUAL-NEXT:      stp     d1, d0, [sp, #-16]!
+; MACHO-MANUAL-NEXT:      stp     d3, d2, [sp, #-16]!
+; MACHO-MANUAL-NEXT:      stp     d5, d4, [sp, #-16]!
+; MACHO-MANUAL-NEXT:      stp     d7, d6, [sp, #-16]!
+; MACHO-MANUAL-NEXT:      bl      _foo_resolver
+; MACHO-MANUAL-NEXT:      adrp    x16, _foo_ifunc.lazy_pointer at GOTPAGE
+; MACHO-MANUAL-NEXT:      ldr     x16, [x16, _foo_ifunc.lazy_pointer at GOTPAGEOFF]
+; MACHO-MANUAL-NEXT:      str     x0, [x16]
+; MACHO-MANUAL-NEXT:      add     x16, x0, #0
+; MACHO-MANUAL-NEXT:      ldp     d7, d6, [sp], #16
+; MACHO-MANUAL-NEXT:      ldp     d5, d4, [sp], #16
+; MACHO-MANUAL-NEXT:      ldp     d3, d2, [sp], #16
+; MACHO-MANUAL-NEXT:      ldp     d1, d0, [sp], #16
+; MACHO-MANUAL-NEXT:      ldp     x7, x6, [sp], #16
+; MACHO-MANUAL-NEXT:      ldp     x5, x4, [sp], #16
+; MACHO-MANUAL-NEXT:      ldp     x3, x2, [sp], #16
+; MACHO-MANUAL-NEXT:      ldp     x1, x0, [sp], #16
+; MACHO-MANUAL-NEXT:      ldp     x29, x30, [sp], #16
+; MACHO-MANUAL-NEXT:      br      x16
+
+
+ at weak_ifunc = weak ifunc i32 (i32), ptr @foo_resolver
+; ELF:             .type weak_ifunc, at gnu_indirect_function
+; MACHO-LINKER:    .symbol_resolver _weak_ifunc
+; MACHO-MANUAL:    _weak_ifunc.stub_helper:
+; MACHO-DEFEAULT:  _weak_ifunc.stub_helper:
\ No newline at end of file

diff  --git a/llvm/test/CodeGen/X86/ifunc-asm.ll b/llvm/test/CodeGen/X86/ifunc-asm.ll
index 4b380c8ae330135..76efda71153207d 100644
--- a/llvm/test/CodeGen/X86/ifunc-asm.ll
+++ b/llvm/test/CodeGen/X86/ifunc-asm.ll
@@ -1,14 +1,24 @@
-; RUN: llvm-as < %s -o - | llc -filetype=asm | FileCheck %s
+; RUN: llc -filetype=asm -mtriple=x86_64-unknown-linux-gnu %s -o - | FileCheck %s --check-prefixes=ELF
+; RUN: llc -filetype=asm -mtriple=x86_64-apple-darwin %s -o - | FileCheck %s --check-prefixes=MACHO
 
-target triple = "x86_64-unknown-linux-gnu"
-
-define internal ptr @foo_ifunc() {
+define internal ptr @foo_resolver() {
 entry:
   ret ptr null
 }
-; CHECK: .type foo_ifunc, at function
-; CHECK-NEXT: foo_ifunc:
+; ELF: .type foo_resolver, at function
+; ELF-NEXT: foo_resolver:
+
+; MACHO: .p2align 4, 0x90
+; MACHO-NEXT: _foo_resolver
+
+
+ at foo_ifunc = ifunc i32 (i32), ptr @foo_resolver
+; ELF:      .globl foo_ifunc
+; ELF-NEXT: .type foo_ifunc, at gnu_indirect_function
+; ELF-NEXT: .set foo_ifunc, foo_resolver
 
- at foo = ifunc i32 (i32), ptr @foo_ifunc
-; CHECK:      .type foo, at gnu_indirect_function
-; CHECK-NEXT: .set foo, foo_ifunc
+; MACHO:      .globl _foo_ifunc
+; MACHO-NEXT: .p2align 4, 0x90
+; MACHO-NEXT: _foo_ifunc:
+; MACHO-NEXT: .symbol_resolver _foo_ifunc
+; MACHO-NEXT: jmp _foo_resolver

diff  --git a/llvm/test/Verifier/ifunc-macho.ll b/llvm/test/Verifier/ifunc-macho.ll
new file mode 100644
index 000000000000000..2e2166645983ac3
--- /dev/null
+++ b/llvm/test/Verifier/ifunc-macho.ll
@@ -0,0 +1,42 @@
+; RUN:  not llvm-as %s -o /dev/null 2>&1 | FileCheck %s
+
+target triple = "arm64-apple-ios"
+
+define ptr @resolver() {
+  ret ptr null
+}
+
+ at g = external global i32
+ at inval_objtype = ifunc void (), ptr @g
+; CHECK: IFunc must have a Function resolver
+
+declare ptr @resolver_decl()
+ at inval_resolver_decl = ifunc void (), ptr @resolver_decl
+; CHECK: IFunc resolver must be a definition
+; CHECK-NEXT: @inval_resolver_decl
+
+define available_externally ptr @resolver_linker_decl() {
+  ret ptr null
+}
+ at inval_resolver_decl2 = ifunc void (), ptr @resolver_linker_decl
+; CHECK: IFunc resolver must be a definition
+; CHECK-NEXT: @inval_resolver_decl2
+
+ at ifunc_nonpointer_return_type = ifunc i32 (), ptr @resolver_returns_nonpointer
+; CHECK: IFunc resolver must return a pointer
+; CHECK-NEXT: ptr @ifunc_nonpointer_return_type
+
+define i32 @resolver_returns_nonpointer() {
+  ret i32 0
+}
+
+ at valid_external = ifunc void (), ptr @resolver
+; CHECK-NOT: valid_external
+
+ at inval_linkonce = linkonce ifunc void (), ptr @resolver
+
+ at inval_weak = weak ifunc void (), ptr @resolver
+
+ at inval_weak_extern = extern_weak ifunc void (), ptr @resolver
+
+ at inval_private = private ifunc void (), ptr @resolver


        


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