[clang][ARM64EC] Add support for hybrid_patchable attribute. #99478
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
llvmbot
added
clang
|
@llvm/pr-subscribers-clang @llvm/pr-subscribers-llvm-transforms Author: Jacek Caban (cjacek) ChangesThis adds support for I added a warning when it's used on static function. Due to the way it works (emitting a reference to an undefined symbol that linker substitutes with a generated thunk), it can't work on static functions. MSVC just silently ignores it; using it like that seems like a non-obvious mistake to me, so I followed MSVC by allowing it too, but emitting an additional warning. The patch does nothing special for function inlining, which matches my experimentation with MSVC. Patch is 37.20 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/99478.diff 19 Files Affected:
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 1293d0ddbc117..2b6d421729322 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -477,6 +477,9 @@ def TargetELF : TargetSpec {
def TargetELFOrMachO : TargetSpec {
let ObjectFormats = ["ELF", "MachO"];
}
+def TargetArm64EC : TargetSpec {
+ let CustomCode = [{ Target.getTriple().isWindowsArm64EC() }];
+}
def TargetSupportsInitPriority : TargetSpec {
let CustomCode = [{ !Target.getTriple().isOSzOS() }];
@@ -4027,6 +4030,12 @@ def SelectAny : InheritableAttr {
let SimpleHandler = 1;
}
+def HybridPatchable : DeclOrTypeAttr, TargetSpecificAttr<TargetArm64EC> {
+ let Spellings = [Declspec<"hybrid_patchable">, GCC<"hybrid_patchable">];
+ let Subjects = SubjectList<[Function]>;
+ let Documentation = [HybridPatchableDocs];
+}
+
def Thread : Attr {
let Spellings = [Declspec<"thread">];
let LangOpts = [MicrosoftExt];
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index 09cf4f80bd999..b5944382ba7a4 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -5984,6 +5984,16 @@ For more information see
or `msvc documentation <https://docs.microsoft.com/pl-pl/cpp/cpp/selectany>`_.
}]; }
+def HybridPatchableDocs : Documentation {
+ let Category = DocCatDecl;
+ let Content = [{
+The ``hybrid_patchable`` attribute declares an ARM64EC function with an additional
+x86-64 thunk, which may be patched in runtime.
+
+For more information see
+`ARM64EC ABI documentation <https://learn.microsoft.com/en-us/windows/arm/arm64ec-abi>`_.
+}]; }
+
def WebAssemblyExportNameDocs : Documentation {
let Category = DocCatFunction;
let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index de3d94155a9a0..60d9f3d0ec022 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3671,6 +3671,9 @@ def err_attribute_weak_static : Error<
"weak declaration cannot have internal linkage">;
def err_attribute_selectany_non_extern_data : Error<
"'selectany' can only be applied to data items with external linkage">;
+def warn_attribute_hybrid_patchable_non_extern : Warning<
+ "'hybrid_patchable' is ignored on functions without external linkage">,
+ InGroup<IgnoredAttributes>;
def err_declspec_thread_on_thread_variable : Error<
"'__declspec(thread)' applied to variable that already has a "
"thread-local storage specifier">;
diff --git a/clang/lib/AST/TypePrinter.cpp b/clang/lib/AST/TypePrinter.cpp
index ffec3ef9d2269..c2c3807399a8a 100644
--- a/clang/lib/AST/TypePrinter.cpp
+++ b/clang/lib/AST/TypePrinter.cpp
@@ -1984,6 +1984,9 @@ void TypePrinter::printAttributedAfter(const AttributedType *T,
case attr::MSABI: OS << "ms_abi"; break;
case attr::SysVABI: OS << "sysv_abi"; break;
case attr::RegCall: OS << "regcall"; break;
+ case attr::HybridPatchable:
+ OS << "hybrid_patchable";
+ break;
case attr::Pcs: {
OS << "pcs(";
QualType t = T->getEquivalentType();
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index ea4635c039cb2..df2f493b3aa4a 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -977,6 +977,9 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
if (D && D->hasAttr<NoProfileFunctionAttr>())
Fn->addFnAttr(llvm::Attribute::NoProfile);
+ if (D && D->hasAttr<HybridPatchableAttr>())
+ Fn->addFnAttr(llvm::Attribute::HybridPatchable);
+
if (D) {
// Function attributes take precedence over command line flags.
if (auto *A = D->getAttr<FunctionReturnThunksAttr>()) {
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 1f2fde12c9d24..0843071ed7ec1 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -6886,6 +6886,13 @@ static void checkAttributesAfterMerging(Sema &S, NamedDecl &ND) {
}
}
+ if (HybridPatchableAttr *Attr = ND.getAttr<HybridPatchableAttr>()) {
+ if (!ND.isExternallyVisible()) {
+ S.Diag(Attr->getLocation(),
+ diag::warn_attribute_hybrid_patchable_non_extern);
+ ND.dropAttr<SelectAnyAttr>();
+ }
+ }
if (const InheritableAttr *Attr = getDLLAttr(&ND)) {
auto *VD = dyn_cast<VarDecl>(&ND);
bool IsAnonymousNS = false;
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 20f46c003a464..edaeef4bdb2de 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -7033,6 +7033,9 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
case ParsedAttr::AT_MSConstexpr:
handleMSConstexprAttr(S, D, AL);
break;
+ case ParsedAttr::AT_HybridPatchable:
+ handleSimpleAttribute<HybridPatchableAttr>(S, D, AL);
+ break;
// HLSL attributes:
case ParsedAttr::AT_HLSLNumThreads:
diff --git a/clang/test/CodeGen/arm64ec-hybrid-patchable.c b/clang/test/CodeGen/arm64ec-hybrid-patchable.c
new file mode 100644
index 0000000000000..30e5c7cdbb102
--- /dev/null
+++ b/clang/test/CodeGen/arm64ec-hybrid-patchable.c
@@ -0,0 +1,29 @@
+// REQUIRES: aarch64-registered-target
+// RUN: %clang_cc1 -triple arm64ec-pc-windows -fms-extensions -emit-llvm -o - %s -verify | FileCheck %s
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define dso_local i32 @func() #0 {
+int __attribute__((hybrid_patchable)) func(void) { return 1; }
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define dso_local i32 @func2() #0 {
+int __declspec(hybrid_patchable) func2(void) { return 2; }
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define dso_local i32 @func3() #0 {
+int __declspec(hybrid_patchable) func3(void);
+int func3(void) { return 3; }
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define internal void @static_func() #0 {
+// expected-warning@+1 {{'hybrid_patchable' is ignored on functions without external linkage}}
+static void __declspec(hybrid_patchable) static_func(void) {}
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define linkonce_odr dso_local i32 @func4() #0 comdat {
+int inline __declspec(hybrid_patchable) func4(void) { return 4; }
+
+void caller(void) {
+ static_func();
+ func4();
+}
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
index 33f9c2f51363c..e082db698ef0c 100644
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -83,6 +83,7 @@
// CHECK-NEXT: HIPManaged (SubjectMatchRule_variable)
// CHECK-NEXT: HLSLResourceClass (SubjectMatchRule_record_not_is_union)
// CHECK-NEXT: Hot (SubjectMatchRule_function)
+// CHECK-NEXT: HybridPatchable (SubjectMatchRule_function)
// CHECK-NEXT: IBAction (SubjectMatchRule_objc_method_is_instance)
// CHECK-NEXT: IFunc (SubjectMatchRule_function)
// CHECK-NEXT: InitPriority (SubjectMatchRule_variable)
diff --git a/llvm/include/llvm/Bitcode/LLVMBitCodes.h b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
index 184bbe32df695..fb88f2fe75adb 100644
--- a/llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -757,6 +757,7 @@ enum AttributeKindCodes {
ATTR_KIND_RANGE = 92,
ATTR_KIND_SANITIZE_NUMERICAL_STABILITY = 93,
ATTR_KIND_INITIALIZES = 94,
+ ATTR_KIND_HYBRID_PATCHABLE = 95,
};
enum ComdatSelectionKindCodes {
diff --git a/llvm/include/llvm/CodeGen/AsmPrinter.h b/llvm/include/llvm/CodeGen/AsmPrinter.h
index dc00bd57d655d..1c4e9e9111441 100644
--- a/llvm/include/llvm/CodeGen/AsmPrinter.h
+++ b/llvm/include/llvm/CodeGen/AsmPrinter.h
@@ -892,7 +892,6 @@ class AsmPrinter : public MachineFunctionPass {
virtual void emitModuleCommandLines(Module &M);
GCMetadataPrinter *getOrCreateGCPrinter(GCStrategy &S);
- virtual void emitGlobalAlias(const Module &M, const GlobalAlias &GA);
void emitGlobalIFunc(Module &M, const GlobalIFunc &GI);
private:
@@ -900,6 +899,7 @@ class AsmPrinter : public MachineFunctionPass {
bool shouldEmitLabelForBasicBlock(const MachineBasicBlock &MBB) const;
protected:
+ virtual void emitGlobalAlias(const Module &M, const GlobalAlias &GA);
virtual bool shouldEmitWeakSwiftAsyncExtendedFramePointerFlags() const {
return false;
}
diff --git a/llvm/include/llvm/IR/Attributes.td b/llvm/include/llvm/IR/Attributes.td
index 0457f0c388d26..e1bd193891c1e 100644
--- a/llvm/include/llvm/IR/Attributes.td
+++ b/llvm/include/llvm/IR/Attributes.td
@@ -112,6 +112,9 @@ def ElementType : TypeAttr<"elementtype", [ParamAttr]>;
/// symbol.
def FnRetThunkExtern : EnumAttr<"fn_ret_thunk_extern", [FnAttr]>;
+/// Function has a hybrid patchable thunk.
+def HybridPatchable : EnumAttr<"hybrid_patchable", [FnAttr]>;
+
/// Pass structure in an alloca.
def InAlloca : TypeAttr<"inalloca", [ParamAttr]>;
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index b3ebe70e8c52f..324dcbca8137e 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -727,6 +727,8 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
return bitc::ATTR_KIND_HOT;
case Attribute::ElementType:
return bitc::ATTR_KIND_ELEMENTTYPE;
+ case Attribute::HybridPatchable:
+ return bitc::ATTR_KIND_HYBRID_PATCHABLE;
case Attribute::InlineHint:
return bitc::ATTR_KIND_INLINE_HINT;
case Attribute::InReg:
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 1f59ec545b4f7..b46a6d348413b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -2859,8 +2859,8 @@ bool AsmPrinter::emitSpecialLLVMGlobal(const GlobalVariable *GV) {
auto *Arr = cast<ConstantArray>(GV->getInitializer());
for (auto &U : Arr->operands()) {
auto *C = cast<Constant>(U);
- auto *Src = cast<Function>(C->getOperand(0)->stripPointerCasts());
- auto *Dst = cast<Function>(C->getOperand(1)->stripPointerCasts());
+ auto *Src = cast<GlobalValue>(C->getOperand(0)->stripPointerCasts());
+ auto *Dst = cast<GlobalValue>(C->getOperand(1)->stripPointerCasts());
int Kind = cast<ConstantInt>(C->getOperand(2))->getZExtValue();
if (Src->hasDLLImportStorageClass()) {
diff --git a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
index 4ff52eb252d20..310b152ef9817 100644
--- a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
@@ -21,6 +21,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/IR/CallingConv.h"
+#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Mangler.h"
@@ -70,15 +71,21 @@ class AArch64Arm64ECCallLowering : public ModulePass {
Function *buildEntryThunk(Function *F);
void lowerCall(CallBase *CB);
Function *buildGuestExitThunk(Function *F);
- bool processFunction(Function &F, SetVector<Function *> &DirectCalledFns);
+ Function *buildPatchableThunk(GlobalAlias *UnmangledAlias,
+ GlobalAlias *MangledAlias);
+ bool processFunction(Function &F, SetVector<GlobalValue *> &DirectCalledFns,
+ DenseMap<GlobalAlias *, GlobalAlias *> &FnsMap);
bool runOnModule(Module &M) override;
private:
int cfguard_module_flag = 0;
FunctionType *GuardFnType = nullptr;
PointerType *GuardFnPtrType = nullptr;
+ FunctionType *DispatchFnType = nullptr;
+ PointerType *DispatchFnPtrType = nullptr;
Constant *GuardFnCFGlobal = nullptr;
Constant *GuardFnGlobal = nullptr;
+ Constant *DispatchFnGlobal = nullptr;
Module *M = nullptr;
Type *PtrTy;
@@ -672,6 +679,66 @@ Function *AArch64Arm64ECCallLowering::buildGuestExitThunk(Function *F) {
return GuestExit;
}
+Function *
+AArch64Arm64ECCallLowering::buildPatchableThunk(GlobalAlias *UnmangledAlias,
+ GlobalAlias *MangledAlias) {
+ llvm::raw_null_ostream NullThunkName;
+ FunctionType *Arm64Ty, *X64Ty;
+ Function *F = cast<Function>(MangledAlias->getAliasee());
+ SmallVector<ThunkArgTranslation> ArgTranslations;
+ getThunkType(F->getFunctionType(), F->getAttributes(),
+ Arm64ECThunkType::GuestExit, NullThunkName, Arm64Ty, X64Ty,
+ ArgTranslations);
+ std::string ThunkName(MangledAlias->getName());
+ if (ThunkName[0] == '?' && ThunkName.find("@") != std::string::npos) {
+ ThunkName.insert(ThunkName.find("@"), "$hybpatch_thunk");
+ } else {
+ ThunkName.append("$hybpatch_thunk");
+ }
+
+ Function *GuestExit =
+ Function::Create(Arm64Ty, GlobalValue::WeakODRLinkage, 0, ThunkName, M);
+ GuestExit->setComdat(M->getOrInsertComdat(ThunkName));
+ GuestExit->setSection(".wowthk$aa");
+ BasicBlock *BB = BasicBlock::Create(M->getContext(), "", GuestExit);
+ IRBuilder<> B(BB);
+
+ // Load the global symbol as a pointer to the check function.
+ LoadInst *DispatchLoad = B.CreateLoad(DispatchFnPtrType, DispatchFnGlobal);
+
+ // Create new dispatch call instruction.
+ Function *ExitThunk =
+ buildExitThunk(F->getFunctionType(), F->getAttributes());
+ CallInst *Dispatch =
+ B.CreateCall(DispatchFnType, DispatchLoad,
+ {UnmangledAlias, ExitThunk, UnmangledAlias->getAliasee()});
+
+ // Ensure that the first arguments are passed in the correct registers.
+ Dispatch->setCallingConv(CallingConv::CFGuard_Check);
+
+ Value *DispatchRetVal = B.CreateBitCast(Dispatch, PtrTy);
+ SmallVector<Value *> Args;
+ for (Argument &Arg : GuestExit->args())
+ Args.push_back(&Arg);
+ CallInst *Call = B.CreateCall(Arm64Ty, DispatchRetVal, Args);
+ Call->setTailCallKind(llvm::CallInst::TCK_MustTail);
+
+ if (Call->getType()->isVoidTy())
+ B.CreateRetVoid();
+ else
+ B.CreateRet(Call);
+
+ auto SRetAttr = F->getAttributes().getParamAttr(0, Attribute::StructRet);
+ auto InRegAttr = F->getAttributes().getParamAttr(0, Attribute::InReg);
+ if (SRetAttr.isValid() && !InRegAttr.isValid()) {
+ GuestExit->addParamAttr(0, SRetAttr);
+ Call->addParamAttr(0, SRetAttr);
+ }
+
+ MangledAlias->setAliasee(GuestExit);
+ return GuestExit;
+}
+
// Lower an indirect call with inline code.
void AArch64Arm64ECCallLowering::lowerCall(CallBase *CB) {
assert(Triple(CB->getModule()->getTargetTriple()).isOSWindows() &&
@@ -727,17 +794,57 @@ bool AArch64Arm64ECCallLowering::runOnModule(Module &Mod) {
GuardFnType = FunctionType::get(PtrTy, {PtrTy, PtrTy}, false);
GuardFnPtrType = PointerType::get(GuardFnType, 0);
+ DispatchFnType = FunctionType::get(PtrTy, {PtrTy, PtrTy, PtrTy}, false);
+ DispatchFnPtrType = PointerType::get(DispatchFnType, 0);
GuardFnCFGlobal =
M->getOrInsertGlobal("__os_arm64x_check_icall_cfg", GuardFnPtrType);
GuardFnGlobal =
M->getOrInsertGlobal("__os_arm64x_check_icall", GuardFnPtrType);
+ DispatchFnGlobal =
+ M->getOrInsertGlobal("__os_arm64x_dispatch_call", DispatchFnPtrType);
+
+ DenseMap<GlobalAlias *, GlobalAlias *> FnsMap;
+ SetVector<GlobalAlias *> PatchableFns;
- SetVector<Function *> DirectCalledFns;
+ for (Function &F : Mod) {
+ if (!F.hasFnAttribute(Attribute::HybridPatchable) || F.isDeclaration() ||
+ F.hasLocalLinkage() || F.getName().ends_with("$hp_target"))
+ continue;
+
+ // Rename hybrid patchable functions and change callers to use a global
+ // alias instead.
+ if (std::optional<std::string> MangledName =
+ getArm64ECMangledFunctionName(F.getName().str())) {
+ std::string OrigName(F.getName());
+ F.setName(MangledName.value() + "$hp_target");
+
+ // The unmangled symbol is a weak alias to an undefined symbol with the
+ // "EXP+" prefix. This undefined symbol is resolved by the linker by
+ // creating an x86 thunk that jumps back to the actual EC target. Since we
+ // can't represent that in IR, we create an alias to the target instead.
+ // The "EXP+" symbol is set as metadata, which is then used by
+ // emitGlobalAlias to emit the right alias.
+ auto *A =
+ GlobalAlias::create(GlobalValue::LinkOnceODRLinkage, OrigName, &F);
+ F.replaceAllUsesWith(A);
+ F.setMetadata("arm64ec_exp_name",
+ MDNode::get(M->getContext(),
+ MDString::get(M->getContext(),
+ "EXP+" + MangledName.value())));
+ A->setAliasee(&F);
+
+ FnsMap[A] = GlobalAlias::create(GlobalValue::LinkOnceODRLinkage,
+ MangledName.value(), &F);
+ PatchableFns.insert(A);
+ }
+ }
+
+ SetVector<GlobalValue *> DirectCalledFns;
for (Function &F : Mod)
if (!F.isDeclaration() &&
F.getCallingConv() != CallingConv::ARM64EC_Thunk_Native &&
F.getCallingConv() != CallingConv::ARM64EC_Thunk_X64)
- processFunction(F, DirectCalledFns);
+ processFunction(F, DirectCalledFns, FnsMap);
struct ThunkInfo {
Constant *Src;
@@ -755,14 +862,20 @@ bool AArch64Arm64ECCallLowering::runOnModule(Module &Mod) {
{&F, buildEntryThunk(&F), Arm64ECThunkType::Entry});
}
}
- for (Function *F : DirectCalledFns) {
+ for (GlobalValue *O : DirectCalledFns) {
+ auto GA = dyn_cast<GlobalAlias>(O);
+ auto F = dyn_cast<Function>(GA ? GA->getAliasee() : O);
ThunkMapping.push_back(
- {F, buildExitThunk(F->getFunctionType(), F->getAttributes()),
+ {O, buildExitThunk(F->getFunctionType(), F->getAttributes()),
Arm64ECThunkType::Exit});
- if (!F->hasDLLImportStorageClass())
+ if (!GA && !F->hasDLLImportStorageClass())
ThunkMapping.push_back(
{buildGuestExitThunk(F), F, Arm64ECThunkType::GuestExit});
}
+ for (GlobalAlias *A : PatchableFns) {
+ Function *Thunk = buildPatchableThunk(A, FnsMap[A]);
+ ThunkMapping.push_back({Thunk, A, Arm64ECThunkType::GuestExit});
+ }
if (!ThunkMapping.empty()) {
SmallVector<Constant *> ThunkMappingArrayElems;
@@ -785,7 +898,8 @@ bool AArch64Arm64ECCallLowering::runOnModule(Module &Mod) {
}
bool AArch64Arm64ECCallLowering::processFunction(
- Function &F, SetVector<Function *> &DirectCalledFns) {
+ Function &F, SetVector<GlobalValue *> &DirectCalledFns,
+ DenseMap<GlobalAlias *, GlobalAlias *> &FnsMap) {
SmallVector<CallBase *, 8> IndirectCalls;
// For ARM64EC targets, a function definition's name is mangled differently
@@ -837,6 +951,16 @@ bool AArch64Arm64ECCallLowering::processFunction(
continue;
}
+ // Use mangled global alias for direct calls to patchable functions.
+ if (GlobalAlias *A = dyn_cast<GlobalAlias>(CB->getCalledOperand())) {
+ auto I = FnsMap.find(A);
+ if (I != FnsMap.end()) {
+ CB->setCalledOperand(I->second);
+ DirectCalledFns.insert(I->first);
+ continue;
+ }
+ }
+
IndirectCalls.push_back(CB);
++Arm64ECCallsLowered;
}
diff --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
index 6f6b551993b6d..63358c1568a35 100644
--- a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -201,6 +201,7 @@ class AArch64AsmPrinter : public AsmPrinter {
void PrintDebugValueComment(const MachineInstr *MI, raw_ostream &OS);
void emitFunctionBodyEnd() override;
+ void emitGlobalAlias(const Module &M, const GlobalAlias &GA) override;
MCSymbol *GetCPISymbol(unsigned CPID) const override;
void emitEndOfAsmFile(Module &M) override;
@@ -1263,6 +1264,32 @@ void AArch64AsmPrinter::emitFunctionEntryLabel() {
}
}
+void AArch64AsmPrinter::emitGlobalAlias(const Module &M,
+ const GlobalAlias &GA) {
+ if (auto F = dyn_cast_or_null<Function>(GA.getAliasee())) {
+ // Global aliases must poin...
[truncated]
|
|
@llvm/pr-subscribers-backend-aarch64 Author: Jacek Caban (cjacek) ChangesThis adds support for I added a warning when it's used on static function. Due to the way it works (emitting a reference to an undefined symbol that linker substitutes with a generated thunk), it can't work on static functions. MSVC just silently ignores it; using it like that seems like a non-obvious mistake to me, so I followed MSVC by allowing it too, but emitting an additional warning. The patch does nothing special for function inlining, which matches my experimentation with MSVC. Patch is 37.20 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/99478.diff 19 Files Affected:
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 1293d0ddbc117..2b6d421729322 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -477,6 +477,9 @@ def TargetELF : TargetSpec {
def TargetELFOrMachO : TargetSpec {
let ObjectFormats = ["ELF", "MachO"];
}
+def TargetArm64EC : TargetSpec {
+ let CustomCode = [{ Target.getTriple().isWindowsArm64EC() }];
+}
def TargetSupportsInitPriority : TargetSpec {
let CustomCode = [{ !Target.getTriple().isOSzOS() }];
@@ -4027,6 +4030,12 @@ def SelectAny : InheritableAttr {
let SimpleHandler = 1;
}
+def HybridPatchable : DeclOrTypeAttr, TargetSpecificAttr<TargetArm64EC> {
+ let Spellings = [Declspec<"hybrid_patchable">, GCC<"hybrid_patchable">];
+ let Subjects = SubjectList<[Function]>;
+ let Documentation = [HybridPatchableDocs];
+}
+
def Thread : Attr {
let Spellings = [Declspec<"thread">];
let LangOpts = [MicrosoftExt];
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index 09cf4f80bd999..b5944382ba7a4 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -5984,6 +5984,16 @@ For more information see
or `msvc documentation <https://docs.microsoft.com/pl-pl/cpp/cpp/selectany>`_.
}]; }
+def HybridPatchableDocs : Documentation {
+ let Category = DocCatDecl;
+ let Content = [{
+The ``hybrid_patchable`` attribute declares an ARM64EC function with an additional
+x86-64 thunk, which may be patched in runtime.
+
+For more information see
+`ARM64EC ABI documentation <https://learn.microsoft.com/en-us/windows/arm/arm64ec-abi>`_.
+}]; }
+
def WebAssemblyExportNameDocs : Documentation {
let Category = DocCatFunction;
let Content = [{
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index de3d94155a9a0..60d9f3d0ec022 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3671,6 +3671,9 @@ def err_attribute_weak_static : Error<
"weak declaration cannot have internal linkage">;
def err_attribute_selectany_non_extern_data : Error<
"'selectany' can only be applied to data items with external linkage">;
+def warn_attribute_hybrid_patchable_non_extern : Warning<
+ "'hybrid_patchable' is ignored on functions without external linkage">,
+ InGroup<IgnoredAttributes>;
def err_declspec_thread_on_thread_variable : Error<
"'__declspec(thread)' applied to variable that already has a "
"thread-local storage specifier">;
diff --git a/clang/lib/AST/TypePrinter.cpp b/clang/lib/AST/TypePrinter.cpp
index ffec3ef9d2269..c2c3807399a8a 100644
--- a/clang/lib/AST/TypePrinter.cpp
+++ b/clang/lib/AST/TypePrinter.cpp
@@ -1984,6 +1984,9 @@ void TypePrinter::printAttributedAfter(const AttributedType *T,
case attr::MSABI: OS << "ms_abi"; break;
case attr::SysVABI: OS << "sysv_abi"; break;
case attr::RegCall: OS << "regcall"; break;
+ case attr::HybridPatchable:
+ OS << "hybrid_patchable";
+ break;
case attr::Pcs: {
OS << "pcs(";
QualType t = T->getEquivalentType();
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index ea4635c039cb2..df2f493b3aa4a 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -977,6 +977,9 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
if (D && D->hasAttr<NoProfileFunctionAttr>())
Fn->addFnAttr(llvm::Attribute::NoProfile);
+ if (D && D->hasAttr<HybridPatchableAttr>())
+ Fn->addFnAttr(llvm::Attribute::HybridPatchable);
+
if (D) {
// Function attributes take precedence over command line flags.
if (auto *A = D->getAttr<FunctionReturnThunksAttr>()) {
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 1f2fde12c9d24..0843071ed7ec1 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -6886,6 +6886,13 @@ static void checkAttributesAfterMerging(Sema &S, NamedDecl &ND) {
}
}
+ if (HybridPatchableAttr *Attr = ND.getAttr<HybridPatchableAttr>()) {
+ if (!ND.isExternallyVisible()) {
+ S.Diag(Attr->getLocation(),
+ diag::warn_attribute_hybrid_patchable_non_extern);
+ ND.dropAttr<SelectAnyAttr>();
+ }
+ }
if (const InheritableAttr *Attr = getDLLAttr(&ND)) {
auto *VD = dyn_cast<VarDecl>(&ND);
bool IsAnonymousNS = false;
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 20f46c003a464..edaeef4bdb2de 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -7033,6 +7033,9 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
case ParsedAttr::AT_MSConstexpr:
handleMSConstexprAttr(S, D, AL);
break;
+ case ParsedAttr::AT_HybridPatchable:
+ handleSimpleAttribute<HybridPatchableAttr>(S, D, AL);
+ break;
// HLSL attributes:
case ParsedAttr::AT_HLSLNumThreads:
diff --git a/clang/test/CodeGen/arm64ec-hybrid-patchable.c b/clang/test/CodeGen/arm64ec-hybrid-patchable.c
new file mode 100644
index 0000000000000..30e5c7cdbb102
--- /dev/null
+++ b/clang/test/CodeGen/arm64ec-hybrid-patchable.c
@@ -0,0 +1,29 @@
+// REQUIRES: aarch64-registered-target
+// RUN: %clang_cc1 -triple arm64ec-pc-windows -fms-extensions -emit-llvm -o - %s -verify | FileCheck %s
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define dso_local i32 @func() #0 {
+int __attribute__((hybrid_patchable)) func(void) { return 1; }
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define dso_local i32 @func2() #0 {
+int __declspec(hybrid_patchable) func2(void) { return 2; }
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define dso_local i32 @func3() #0 {
+int __declspec(hybrid_patchable) func3(void);
+int func3(void) { return 3; }
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define internal void @static_func() #0 {
+// expected-warning@+1 {{'hybrid_patchable' is ignored on functions without external linkage}}
+static void __declspec(hybrid_patchable) static_func(void) {}
+
+// CHECK: ; Function Attrs: hybrid_patchable noinline nounwind optnone
+// CHECK-NEXT: define linkonce_odr dso_local i32 @func4() #0 comdat {
+int inline __declspec(hybrid_patchable) func4(void) { return 4; }
+
+void caller(void) {
+ static_func();
+ func4();
+}
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
index 33f9c2f51363c..e082db698ef0c 100644
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -83,6 +83,7 @@
// CHECK-NEXT: HIPManaged (SubjectMatchRule_variable)
// CHECK-NEXT: HLSLResourceClass (SubjectMatchRule_record_not_is_union)
// CHECK-NEXT: Hot (SubjectMatchRule_function)
+// CHECK-NEXT: HybridPatchable (SubjectMatchRule_function)
// CHECK-NEXT: IBAction (SubjectMatchRule_objc_method_is_instance)
// CHECK-NEXT: IFunc (SubjectMatchRule_function)
// CHECK-NEXT: InitPriority (SubjectMatchRule_variable)
diff --git a/llvm/include/llvm/Bitcode/LLVMBitCodes.h b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
index 184bbe32df695..fb88f2fe75adb 100644
--- a/llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -757,6 +757,7 @@ enum AttributeKindCodes {
ATTR_KIND_RANGE = 92,
ATTR_KIND_SANITIZE_NUMERICAL_STABILITY = 93,
ATTR_KIND_INITIALIZES = 94,
+ ATTR_KIND_HYBRID_PATCHABLE = 95,
};
enum ComdatSelectionKindCodes {
diff --git a/llvm/include/llvm/CodeGen/AsmPrinter.h b/llvm/include/llvm/CodeGen/AsmPrinter.h
index dc00bd57d655d..1c4e9e9111441 100644
--- a/llvm/include/llvm/CodeGen/AsmPrinter.h
+++ b/llvm/include/llvm/CodeGen/AsmPrinter.h
@@ -892,7 +892,6 @@ class AsmPrinter : public MachineFunctionPass {
virtual void emitModuleCommandLines(Module &M);
GCMetadataPrinter *getOrCreateGCPrinter(GCStrategy &S);
- virtual void emitGlobalAlias(const Module &M, const GlobalAlias &GA);
void emitGlobalIFunc(Module &M, const GlobalIFunc &GI);
private:
@@ -900,6 +899,7 @@ class AsmPrinter : public MachineFunctionPass {
bool shouldEmitLabelForBasicBlock(const MachineBasicBlock &MBB) const;
protected:
+ virtual void emitGlobalAlias(const Module &M, const GlobalAlias &GA);
virtual bool shouldEmitWeakSwiftAsyncExtendedFramePointerFlags() const {
return false;
}
diff --git a/llvm/include/llvm/IR/Attributes.td b/llvm/include/llvm/IR/Attributes.td
index 0457f0c388d26..e1bd193891c1e 100644
--- a/llvm/include/llvm/IR/Attributes.td
+++ b/llvm/include/llvm/IR/Attributes.td
@@ -112,6 +112,9 @@ def ElementType : TypeAttr<"elementtype", [ParamAttr]>;
/// symbol.
def FnRetThunkExtern : EnumAttr<"fn_ret_thunk_extern", [FnAttr]>;
+/// Function has a hybrid patchable thunk.
+def HybridPatchable : EnumAttr<"hybrid_patchable", [FnAttr]>;
+
/// Pass structure in an alloca.
def InAlloca : TypeAttr<"inalloca", [ParamAttr]>;
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index b3ebe70e8c52f..324dcbca8137e 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -727,6 +727,8 @@ static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
return bitc::ATTR_KIND_HOT;
case Attribute::ElementType:
return bitc::ATTR_KIND_ELEMENTTYPE;
+ case Attribute::HybridPatchable:
+ return bitc::ATTR_KIND_HYBRID_PATCHABLE;
case Attribute::InlineHint:
return bitc::ATTR_KIND_INLINE_HINT;
case Attribute::InReg:
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 1f59ec545b4f7..b46a6d348413b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -2859,8 +2859,8 @@ bool AsmPrinter::emitSpecialLLVMGlobal(const GlobalVariable *GV) {
auto *Arr = cast<ConstantArray>(GV->getInitializer());
for (auto &U : Arr->operands()) {
auto *C = cast<Constant>(U);
- auto *Src = cast<Function>(C->getOperand(0)->stripPointerCasts());
- auto *Dst = cast<Function>(C->getOperand(1)->stripPointerCasts());
+ auto *Src = cast<GlobalValue>(C->getOperand(0)->stripPointerCasts());
+ auto *Dst = cast<GlobalValue>(C->getOperand(1)->stripPointerCasts());
int Kind = cast<ConstantInt>(C->getOperand(2))->getZExtValue();
if (Src->hasDLLImportStorageClass()) {
diff --git a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
index 4ff52eb252d20..310b152ef9817 100644
--- a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
@@ -21,6 +21,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/IR/CallingConv.h"
+#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Mangler.h"
@@ -70,15 +71,21 @@ class AArch64Arm64ECCallLowering : public ModulePass {
Function *buildEntryThunk(Function *F);
void lowerCall(CallBase *CB);
Function *buildGuestExitThunk(Function *F);
- bool processFunction(Function &F, SetVector<Function *> &DirectCalledFns);
+ Function *buildPatchableThunk(GlobalAlias *UnmangledAlias,
+ GlobalAlias *MangledAlias);
+ bool processFunction(Function &F, SetVector<GlobalValue *> &DirectCalledFns,
+ DenseMap<GlobalAlias *, GlobalAlias *> &FnsMap);
bool runOnModule(Module &M) override;
private:
int cfguard_module_flag = 0;
FunctionType *GuardFnType = nullptr;
PointerType *GuardFnPtrType = nullptr;
+ FunctionType *DispatchFnType = nullptr;
+ PointerType *DispatchFnPtrType = nullptr;
Constant *GuardFnCFGlobal = nullptr;
Constant *GuardFnGlobal = nullptr;
+ Constant *DispatchFnGlobal = nullptr;
Module *M = nullptr;
Type *PtrTy;
@@ -672,6 +679,66 @@ Function *AArch64Arm64ECCallLowering::buildGuestExitThunk(Function *F) {
return GuestExit;
}
+Function *
+AArch64Arm64ECCallLowering::buildPatchableThunk(GlobalAlias *UnmangledAlias,
+ GlobalAlias *MangledAlias) {
+ llvm::raw_null_ostream NullThunkName;
+ FunctionType *Arm64Ty, *X64Ty;
+ Function *F = cast<Function>(MangledAlias->getAliasee());
+ SmallVector<ThunkArgTranslation> ArgTranslations;
+ getThunkType(F->getFunctionType(), F->getAttributes(),
+ Arm64ECThunkType::GuestExit, NullThunkName, Arm64Ty, X64Ty,
+ ArgTranslations);
+ std::string ThunkName(MangledAlias->getName());
+ if (ThunkName[0] == '?' && ThunkName.find("@") != std::string::npos) {
+ ThunkName.insert(ThunkName.find("@"), "$hybpatch_thunk");
+ } else {
+ ThunkName.append("$hybpatch_thunk");
+ }
+
+ Function *GuestExit =
+ Function::Create(Arm64Ty, GlobalValue::WeakODRLinkage, 0, ThunkName, M);
+ GuestExit->setComdat(M->getOrInsertComdat(ThunkName));
+ GuestExit->setSection(".wowthk$aa");
+ BasicBlock *BB = BasicBlock::Create(M->getContext(), "", GuestExit);
+ IRBuilder<> B(BB);
+
+ // Load the global symbol as a pointer to the check function.
+ LoadInst *DispatchLoad = B.CreateLoad(DispatchFnPtrType, DispatchFnGlobal);
+
+ // Create new dispatch call instruction.
+ Function *ExitThunk =
+ buildExitThunk(F->getFunctionType(), F->getAttributes());
+ CallInst *Dispatch =
+ B.CreateCall(DispatchFnType, DispatchLoad,
+ {UnmangledAlias, ExitThunk, UnmangledAlias->getAliasee()});
+
+ // Ensure that the first arguments are passed in the correct registers.
+ Dispatch->setCallingConv(CallingConv::CFGuard_Check);
+
+ Value *DispatchRetVal = B.CreateBitCast(Dispatch, PtrTy);
+ SmallVector<Value *> Args;
+ for (Argument &Arg : GuestExit->args())
+ Args.push_back(&Arg);
+ CallInst *Call = B.CreateCall(Arm64Ty, DispatchRetVal, Args);
+ Call->setTailCallKind(llvm::CallInst::TCK_MustTail);
+
+ if (Call->getType()->isVoidTy())
+ B.CreateRetVoid();
+ else
+ B.CreateRet(Call);
+
+ auto SRetAttr = F->getAttributes().getParamAttr(0, Attribute::StructRet);
+ auto InRegAttr = F->getAttributes().getParamAttr(0, Attribute::InReg);
+ if (SRetAttr.isValid() && !InRegAttr.isValid()) {
+ GuestExit->addParamAttr(0, SRetAttr);
+ Call->addParamAttr(0, SRetAttr);
+ }
+
+ MangledAlias->setAliasee(GuestExit);
+ return GuestExit;
+}
+
// Lower an indirect call with inline code.
void AArch64Arm64ECCallLowering::lowerCall(CallBase *CB) {
assert(Triple(CB->getModule()->getTargetTriple()).isOSWindows() &&
@@ -727,17 +794,57 @@ bool AArch64Arm64ECCallLowering::runOnModule(Module &Mod) {
GuardFnType = FunctionType::get(PtrTy, {PtrTy, PtrTy}, false);
GuardFnPtrType = PointerType::get(GuardFnType, 0);
+ DispatchFnType = FunctionType::get(PtrTy, {PtrTy, PtrTy, PtrTy}, false);
+ DispatchFnPtrType = PointerType::get(DispatchFnType, 0);
GuardFnCFGlobal =
M->getOrInsertGlobal("__os_arm64x_check_icall_cfg", GuardFnPtrType);
GuardFnGlobal =
M->getOrInsertGlobal("__os_arm64x_check_icall", GuardFnPtrType);
+ DispatchFnGlobal =
+ M->getOrInsertGlobal("__os_arm64x_dispatch_call", DispatchFnPtrType);
+
+ DenseMap<GlobalAlias *, GlobalAlias *> FnsMap;
+ SetVector<GlobalAlias *> PatchableFns;
- SetVector<Function *> DirectCalledFns;
+ for (Function &F : Mod) {
+ if (!F.hasFnAttribute(Attribute::HybridPatchable) || F.isDeclaration() ||
+ F.hasLocalLinkage() || F.getName().ends_with("$hp_target"))
+ continue;
+
+ // Rename hybrid patchable functions and change callers to use a global
+ // alias instead.
+ if (std::optional<std::string> MangledName =
+ getArm64ECMangledFunctionName(F.getName().str())) {
+ std::string OrigName(F.getName());
+ F.setName(MangledName.value() + "$hp_target");
+
+ // The unmangled symbol is a weak alias to an undefined symbol with the
+ // "EXP+" prefix. This undefined symbol is resolved by the linker by
+ // creating an x86 thunk that jumps back to the actual EC target. Since we
+ // can't represent that in IR, we create an alias to the target instead.
+ // The "EXP+" symbol is set as metadata, which is then used by
+ // emitGlobalAlias to emit the right alias.
+ auto *A =
+ GlobalAlias::create(GlobalValue::LinkOnceODRLinkage, OrigName, &F);
+ F.replaceAllUsesWith(A);
+ F.setMetadata("arm64ec_exp_name",
+ MDNode::get(M->getContext(),
+ MDString::get(M->getContext(),
+ "EXP+" + MangledName.value())));
+ A->setAliasee(&F);
+
+ FnsMap[A] = GlobalAlias::create(GlobalValue::LinkOnceODRLinkage,
+ MangledName.value(), &F);
+ PatchableFns.insert(A);
+ }
+ }
+
+ SetVector<GlobalValue *> DirectCalledFns;
for (Function &F : Mod)
if (!F.isDeclaration() &&
F.getCallingConv() != CallingConv::ARM64EC_Thunk_Native &&
F.getCallingConv() != CallingConv::ARM64EC_Thunk_X64)
- processFunction(F, DirectCalledFns);
+ processFunction(F, DirectCalledFns, FnsMap);
struct ThunkInfo {
Constant *Src;
@@ -755,14 +862,20 @@ bool AArch64Arm64ECCallLowering::runOnModule(Module &Mod) {
{&F, buildEntryThunk(&F), Arm64ECThunkType::Entry});
}
}
- for (Function *F : DirectCalledFns) {
+ for (GlobalValue *O : DirectCalledFns) {
+ auto GA = dyn_cast<GlobalAlias>(O);
+ auto F = dyn_cast<Function>(GA ? GA->getAliasee() : O);
ThunkMapping.push_back(
- {F, buildExitThunk(F->getFunctionType(), F->getAttributes()),
+ {O, buildExitThunk(F->getFunctionType(), F->getAttributes()),
Arm64ECThunkType::Exit});
- if (!F->hasDLLImportStorageClass())
+ if (!GA && !F->hasDLLImportStorageClass())
ThunkMapping.push_back(
{buildGuestExitThunk(F), F, Arm64ECThunkType::GuestExit});
}
+ for (GlobalAlias *A : PatchableFns) {
+ Function *Thunk = buildPatchableThunk(A, FnsMap[A]);
+ ThunkMapping.push_back({Thunk, A, Arm64ECThunkType::GuestExit});
+ }
if (!ThunkMapping.empty()) {
SmallVector<Constant *> ThunkMappingArrayElems;
@@ -785,7 +898,8 @@ bool AArch64Arm64ECCallLowering::runOnModule(Module &Mod) {
}
bool AArch64Arm64ECCallLowering::processFunction(
- Function &F, SetVector<Function *> &DirectCalledFns) {
+ Function &F, SetVector<GlobalValue *> &DirectCalledFns,
+ DenseMap<GlobalAlias *, GlobalAlias *> &FnsMap) {
SmallVector<CallBase *, 8> IndirectCalls;
// For ARM64EC targets, a function definition's name is mangled differently
@@ -837,6 +951,16 @@ bool AArch64Arm64ECCallLowering::processFunction(
continue;
}
+ // Use mangled global alias for direct calls to patchable functions.
+ if (GlobalAlias *A = dyn_cast<GlobalAlias>(CB->getCalledOperand())) {
+ auto I = FnsMap.find(A);
+ if (I != FnsMap.end()) {
+ CB->setCalledOperand(I->second);
+ DirectCalledFns.insert(I->first);
+ continue;
+ }
+ }
+
IndirectCalls.push_back(CB);
++Arm64ECCallsLowered;
}
diff --git a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
index 6f6b551993b6d..63358c1568a35 100644
--- a/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
+++ b/llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
@@ -201,6 +201,7 @@ class AArch64AsmPrinter : public AsmPrinter {
void PrintDebugValueComment(const MachineInstr *MI, raw_ostream &OS);
void emitFunctionBodyEnd() override;
+ void emitGlobalAlias(const Module &M, const GlobalAlias &GA) override;
MCSymbol *GetCPISymbol(unsigned CPID) const override;
void emitEndOfAsmFile(Module &M) override;
@@ -1263,6 +1264,32 @@ void AArch64AsmPrinter::emitFunctionEntryLabel() {
}
}
+void AArch64AsmPrinter::emitGlobalAlias(const Module &M,
+ const GlobalAlias &GA) {
+ if (auto F = dyn_cast_or_null<Function>(GA.getAliasee())) {
+ // Global aliases must poin...
[truncated]
|
clang/include/clang/Basic/Attr.td
Outdated
| @@ -4027,6 +4030,12 @@ def SelectAny : InheritableAttr { | |||
| let SimpleHandler = 1; | |||
| } | |||
|
|
|||
| def HybridPatchable : DeclOrTypeAttr, TargetSpecificAttr<TargetArm64EC> { | |||
| let Spellings = [Declspec<"hybrid_patchable">, GCC<"hybrid_patchable">]; | |||
There was a problem hiding this comment.
I don't see any evidence that GCC supports this attribute, were you aiming for supporting __attribute__((hybrid_patchable)) and not [[gnu::hybrid_patchable]]? If so, that would be a GNU spelling instead of a GCC spelling, but we typically would use a Clang spelling so that [[clang::hybrid_patchable]] works.
There was a problem hiding this comment.
Yes, I was thinking mostly about __attribute__((hybrid_patchable)) as it's the form that mingw will mostly likely want to use, so I meant GNU. Clang sounds good to me if proffered, I changed that and added a test for it.
clang/include/clang/Basic/Attr.td
Outdated
| @@ -477,6 +477,9 @@ def TargetELF : TargetSpec { | |||
| def TargetELFOrMachO : TargetSpec { | |||
| let ObjectFormats = ["ELF", "MachO"]; | |||
| } | |||
| def TargetArm64EC : TargetSpec { | |||
There was a problem hiding this comment.
Should this say Windows somewhere in the name to make it more clear that this isn't an ARM64 attribute in general?
There was a problem hiding this comment.
I renamed it to TargetWindowsArm64EC in the new version.
clang/include/clang/Basic/Attr.td
Outdated
| @@ -4027,6 +4030,12 @@ def SelectAny : InheritableAttr { | |||
| let SimpleHandler = 1; | |||
| } | |||
|
|
|||
| def HybridPatchable : DeclOrTypeAttr, TargetSpecificAttr<TargetArm64EC> { | |||
There was a problem hiding this comment.
You've specified this as a type attribute but implemented it purely as a declaration attribute; did you intend for this to be InheritableAttr instead?
There was a problem hiding this comment.
Right, I don't remember why I did it like that. I changed it in the new version.
clang/lib/Sema/SemaDecl.cpp
Outdated
| if (!ND.isExternallyVisible()) { | ||
| S.Diag(Attr->getLocation(), | ||
| diag::warn_attribute_hybrid_patchable_non_extern); | ||
| ND.dropAttr<SelectAnyAttr>(); |
There was a problem hiding this comment.
Suggested change
| ND.dropAttr<SelectAnyAttr>(); | |
| ND.dropAttr<HybridPatchableAttr>(); |
There was a problem hiding this comment.
Good point, it was a copoy&paste typo. Actually, we don't really need it as LLVM part ignores the attribute for static functions itself. I removed that line and left only diagnostics part here to slightly simplify the code.
cjacek
force-pushed
the
clang-hybrid-patchable
branch
from
1ac6b1b to
31584aa
Compare
I included release notes changelog in the new version. I also rebased it on top of merged #92965 and addressed other comments. Thanks for reviews! |
efriedma-quic
approved these changes
Jul 25, 2024
There was a problem hiding this comment.
LGTM
(Please cherry-pick to 19; I'd like to have this in 19. And maybe cjacek@4febef2, if you wouldn't mind opening a pull request for that.)
|
/cherry-pick ea98dc8 |
|
Thanks. I created #100872 for dllexport fix. |
Error: Command failed due to missing milestone. |
|
/cherry-pick ea98dc8 |
llvmbot
pushed a commit
to llvmbot/llvm-project
that referenced
this pull request
Jul 27, 2024
) (cherry picked from commit ea98dc8)
|
/pull-request #100873 |
tru
pushed a commit
to llvmbot/llvm-project
that referenced
this pull request
Jul 30, 2024
) (cherry picked from commit ea98dc8)
pradt2
pushed a commit
to pradt2/llvm-project
that referenced
this pull request
Feb 11, 2025
) (cherry picked from commit ea98dc8)
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This adds support for
hybrid_patchableon top of LLVM part from #92965 (so it depends on #92965 and this PR is meant only for the second commit). For the most part, it just adds LLVM attribute whenever C/C++ attribute is specified.I added a warning when it's used on static function. Due to the way it works (emitting a reference to an undefined symbol that linker substitutes with a generated thunk), it can't work on static functions. MSVC just silently ignores it; using it like that seems like a non-obvious mistake to me, so I followed MSVC by allowing it too, but emitting an additional warning.
The patch does nothing special for function inlining, which matches my experimentation with MSVC.
hybrid_patchablefunctions may be specified on inline functions. Depending on optimizations taken, when they are actually inlined, it has no effect, but when they are not inlined, it works as expected.