https://github.com/w2yehia created
https://github.com/llvm/llvm-project/pull/153049
None
>From ed0bc14a65e718aaead6eb9397dad9b289e72c91 Mon Sep 17 00:00:00 2001
From: Wael Yehia <wye...@ca.ibm.com>
Date: Mon, 11 Aug 2025 15:56:25 +0000
Subject: [PATCH 1/3] Create and implement lowering of two intrinsics:
int.ppc.get.function.descriptor int.ppc.get.function.entry
---
llvm/include/llvm/IR/IntrinsicsPowerPC.td | 10 ++++++++
llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp | 8 +++++--
llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp | 4 ++++
llvm/lib/Target/PowerPC/PPCISelLowering.cpp | 26 +++++++++++++++++++++
4 files changed, 46 insertions(+), 2 deletions(-)
diff --git a/llvm/include/llvm/IR/IntrinsicsPowerPC.td
b/llvm/include/llvm/IR/IntrinsicsPowerPC.td
index 7dd9ff7f08b8b..75b64fba6e3ca 100644
--- a/llvm/include/llvm/IR/IntrinsicsPowerPC.td
+++ b/llvm/include/llvm/IR/IntrinsicsPowerPC.td
@@ -2090,3 +2090,13 @@ let TargetPrefix = "ppc" in {
Intrinsic<[], [llvm_i64_ty, llvm_i64_ty, llvm_ptr_ty],
[IntrArgMemOnly, IntrWriteMem, NoCapture<ArgIndex<2>>]>;
}
+
+
+//===----------------------------------------------------------------------===//
+// XCOFF Intrinsics
+let TargetPrefix = "ppc" in {
+ def int_ppc_get_function_entry :
+ DefaultAttrsIntrinsic<[llvm_ptr_ty], [llvm_ptr_ty], [IntrNoMem]>;
+ def int_ppc_get_function_descriptor :
+ DefaultAttrsIntrinsic<[llvm_ptr_ty], [llvm_ptr_ty], [IntrNoMem]>;
+}
diff --git a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 2ab2c147be0ec..957b2b3e7555d 100644
--- a/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -763,6 +763,8 @@ static MCSymbol *getMCSymbolForTOCPseudoMO(const
MachineOperand &MO,
return AP.GetJTISymbol(MO.getIndex());
case MachineOperand::MO_BlockAddress:
return AP.GetBlockAddressSymbol(MO.getBlockAddress());
+ case MachineOperand::MO_MCSymbol:
+ return MO.getMCSymbol();
default:
llvm_unreachable("Unexpected operand type to get symbol.");
}
@@ -792,6 +794,8 @@ getTOCEntryTypeForMO(const MachineOperand &MO) {
return PPCAsmPrinter::TOCType_JumpTable;
case MachineOperand::MO_BlockAddress:
return PPCAsmPrinter::TOCType_BlockAddress;
+ case MachineOperand::MO_MCSymbol:
+ return PPCAsmPrinter::TOCType_GlobalExternal; // TODO
default:
llvm_unreachable("Unexpected operand type to get TOC type.");
}
@@ -1043,7 +1047,7 @@ void PPCAsmPrinter::emitInstruction(const MachineInstr
*MI) {
TmpInst.setOpcode(PPC::LWZ);
const MachineOperand &MO = MI->getOperand(1);
- assert((MO.isGlobal() || MO.isCPI() || MO.isJTI() || MO.isBlockAddress())
&&
+ assert((MO.isGlobal() || MO.isCPI() || MO.isJTI() || MO.isBlockAddress()
|| MO.isMCSymbol()) &&
"Invalid operand for LWZtoc.");
// Map the operand to its corresponding MCSymbol.
@@ -1127,7 +1131,7 @@ void PPCAsmPrinter::emitInstruction(const MachineInstr
*MI) {
TmpInst.setOpcode(PPC::LD);
const MachineOperand &MO = MI->getOperand(1);
- assert((MO.isGlobal() || MO.isCPI() || MO.isJTI() || MO.isBlockAddress())
&&
+ assert((MO.isGlobal() || MO.isCPI() || MO.isJTI() || MO.isBlockAddress()
|| MO.isMCSymbol()) &&
"Invalid operand!");
// Map the operand to its corresponding MCSymbol.
diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 415164fc9e2cb..921cb72a83030 100644
--- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -6158,6 +6158,10 @@ void PPCDAGToDAGISel::Select(SDNode *N) {
replaceWith(PPC::ADDItoc8, N, MVT::i64);
return;
}
+ if (N->getOperand(0).getOpcode() == ISD::MCSymbol) {
+ replaceWith(PPC::LDtoc, N, MVT::i64);
+ return;
+ }
// Break if it doesn't have toc data attribute. Proceed with common
// SelectCode.
break;
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 74ae8502dccea..bbdd573f4a81b 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -11167,6 +11167,32 @@ SDValue
PPCTargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op,
SDLoc dl(Op);
switch (IntrinsicID) {
+ case Intrinsic::ppc_get_function_descriptor:
+ return Op.getOperand(1);
+ case Intrinsic::ppc_get_function_entry: {
+ SDValue Op1 = Op.getOperand(1);
+ if (auto *G = dyn_cast<GlobalAddressSDNode>(Op1)) {
+ const GlobalValue *GV = G->getGlobal();
+ assert(isFunctionGlobalAddress(GV));
+ assert(Subtarget.isAIXABI());
+ assert(!isa<GlobalIFunc>(GV) && "IFunc is not supported on AIX.");
+ const TargetMachine &TM = Subtarget.getTargetMachine();
+ const TargetLoweringObjectFile *TLOF = TM.getObjFileLowering();
+ MCSymbolXCOFF *S =
+ cast<MCSymbolXCOFF>(TLOF->getFunctionEntryPointSymbol(GV, TM));
+
+ MVT PtrVT =
DAG.getTargetLoweringInfo().getPointerTy(DAG.getDataLayout());
+ SDValue EntryPointSym = DAG.getMCSymbol(S, PtrVT);
+ return getTOCEntry(DAG, dl, EntryPointSym);
+ }
+ assert (Op1.getOpcode() == ISD::CopyFromReg);
+ SDLoc dl(Op);
+ EVT PtrVT = getPointerTy(DAG.getDataLayout());
+ SDValue Result = DAG.getLoad(
+ PtrVT, dl, DAG.getEntryNode(), Op1, MachinePointerInfo(),
DAG.getDataLayout().getPointerABIAlignment(0),
+ MachineMemOperand::MODereferenceable);
+ return Result;
+ }
case Intrinsic::thread_pointer:
// Reads the thread pointer register, used for __builtin_thread_pointer.
if (Subtarget.isPPC64())
>From e402550f411947bfcf3afc2dae0b3462e5b6c90c Mon Sep 17 00:00:00 2001
From: Wael Yehia <wye...@ca.ibm.com>
Date: Tue, 5 Aug 2025 18:01:19 +0000
Subject: [PATCH 2/3] accept ifunc attribute on AIX
---
clang/include/clang/Basic/TargetInfo.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/clang/include/clang/Basic/TargetInfo.h
b/clang/include/clang/Basic/TargetInfo.h
index ce4677e540226..ffeab27b67911 100644
--- a/clang/include/clang/Basic/TargetInfo.h
+++ b/clang/include/clang/Basic/TargetInfo.h
@@ -1545,6 +1545,8 @@ class TargetInfo : public TransferrableTargetInfo,
return true;
if (getTriple().getArch() == llvm::Triple::ArchType::avr)
return true;
+ if (getTriple().isOSAIX())
+ return true;
return getTriple().isOSBinFormatELF() &&
((getTriple().isOSLinux() && !getTriple().isMusl()) ||
getTriple().isOSFreeBSD());
>From a6c86372d870e737351b26a3e616912ff3c62d3f Mon Sep 17 00:00:00 2001
From: Wael Yehia <wye...@ca.ibm.com>
Date: Mon, 11 Aug 2025 16:01:25 +0000
Subject: [PATCH 3/3] initial LowerIFuncsOnAIX impl
---
.../llvm/Transforms/Utils/ModuleUtils.h | 7 ++
llvm/lib/Target/PowerPC/PPCTargetMachine.cpp | 11 +++
llvm/lib/Target/PowerPC/PPCTargetMachine.h | 2 +
llvm/lib/Transforms/Utils/LowerIFunc.cpp | 7 +-
llvm/lib/Transforms/Utils/ModuleUtils.cpp | 81 +++++++++++++++++++
5 files changed, 107 insertions(+), 1 deletion(-)
diff --git a/llvm/include/llvm/Transforms/Utils/ModuleUtils.h
b/llvm/include/llvm/Transforms/Utils/ModuleUtils.h
index 4036c4e947c75..6be7ac80dd428 100644
--- a/llvm/include/llvm/Transforms/Utils/ModuleUtils.h
+++ b/llvm/include/llvm/Transforms/Utils/ModuleUtils.h
@@ -159,6 +159,13 @@ LLVM_ABI bool
lowerGlobalIFuncUsersAsGlobalCtor(Module &M,
ArrayRef<GlobalIFunc *> IFuncsToLower = {});
+/// AIX specific lowering of ifuncs where we convert an ifunc to a regular
+/// function with the following implementation:
+/// Check if the function's descriptor still points to itself (true on first
+/// entry), if so then call the resolver function and atomically store the
+/// resulting function pointer into the descriptor. Make an indirect call
+/// through the function pointer in the descriptor.
+LLVM_ABI void lowerIFuncsOnAIX(Module &M);
} // End llvm namespace
#endif // LLVM_TRANSFORMS_UTILS_MODULEUTILS_H
diff --git a/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
b/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
index b5c6ac111dff0..d8e840912bc37 100644
--- a/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
+++ b/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
@@ -36,6 +36,7 @@
#include "llvm/InitializePasses.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Pass.h"
+#include "llvm/Passes/PassBuilder.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
@@ -43,6 +44,7 @@
#include "llvm/Target/TargetOptions.h"
#include "llvm/TargetParser/Triple.h"
#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/LowerIFunc.h"
#include <cassert>
#include <memory>
#include <optional>
@@ -452,6 +454,15 @@ class PPCPassConfig : public TargetPassConfig {
} // end anonymous namespace
+void PPCTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB) {
+ if (getTargetTriple().isOSAIX())
+ PB.registerOptimizerLastEPCallback(
+ [](ModulePassManager &PM, OptimizationLevel Level, ThinOrFullLTOPhase
Phase) {
+ if (Phase == ThinOrFullLTOPhase::None)
+ PM.addPass(LowerIFuncPass());
+ });
+}
+
TargetPassConfig *PPCTargetMachine::createPassConfig(PassManagerBase &PM) {
return new PPCPassConfig(*this, PM);
}
diff --git a/llvm/lib/Target/PowerPC/PPCTargetMachine.h
b/llvm/lib/Target/PowerPC/PPCTargetMachine.h
index cb02b446fadb3..608750f7a3f2b 100644
--- a/llvm/lib/Target/PowerPC/PPCTargetMachine.h
+++ b/llvm/lib/Target/PowerPC/PPCTargetMachine.h
@@ -54,6 +54,8 @@ class PPCTargetMachine final : public
CodeGenTargetMachineImpl {
// Pass Pipeline Configuration
TargetPassConfig *createPassConfig(PassManagerBase &PM) override;
+ void registerPassBuilderCallbacks(PassBuilder &PB) override;
+
TargetTransformInfo getTargetTransformInfo(const Function &F) const override;
TargetLoweringObjectFile *getObjFileLowering() const override {
diff --git a/llvm/lib/Transforms/Utils/LowerIFunc.cpp
b/llvm/lib/Transforms/Utils/LowerIFunc.cpp
index 18ae0bbe2e731..991890aa56b83 100644
--- a/llvm/lib/Transforms/Utils/LowerIFunc.cpp
+++ b/llvm/lib/Transforms/Utils/LowerIFunc.cpp
@@ -13,6 +13,7 @@
#include "llvm/Transforms/Utils/LowerIFunc.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
+#include "llvm/TargetParser/Triple.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
using namespace llvm;
@@ -22,6 +23,10 @@ PreservedAnalyses LowerIFuncPass::run(Module &M,
ModuleAnalysisManager &AM) {
if (M.ifunc_empty())
return PreservedAnalyses::all();
- lowerGlobalIFuncUsersAsGlobalCtor(M, {});
+ Triple TargetTriple(M.getTargetTriple());
+ if (TargetTriple.isOSAIX())
+ lowerIFuncsOnAIX(M);
+ else
+ lowerGlobalIFuncUsersAsGlobalCtor(M, {});
return PreservedAnalyses::none();
}
diff --git a/llvm/lib/Transforms/Utils/ModuleUtils.cpp
b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
index 596849ecab742..67da3e66cf16a 100644
--- a/llvm/lib/Transforms/Utils/ModuleUtils.cpp
+++ b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
@@ -16,6 +16,8 @@
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/IntrinsicsPowerPC.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Casting.h"
@@ -397,6 +399,85 @@ void llvm::embedBufferInModule(Module &M, MemoryBufferRef
Buf,
appendToCompilerUsed(M, GV);
}
+void llvm::lowerIFuncsOnAIX(Module &M) {
+ for (GlobalIFunc &IFunc : make_early_inc_range(M.ifuncs())) {
+
+ // Let IFunc be:
+ // @foo = ifunc rt-type (type1, type2), ptr @resolver
+ assert(isa<llvm::FunctionType>(IFunc.getValueType()));
+ FunctionType *FTy = cast<llvm::FunctionType>(IFunc.getValueType());
+
+ // Create the regular (non-ifunc) function:
+ // define rt-type @foo(type1 %0, type2 %1)
+ Function *F = Function::Create(FTy, IFunc.getLinkage(),
IFunc.getAddressSpace(), IFunc.getName(), &M);
+ LLVMContext &Ctx = F->getContext();
+
+ // entry:
+ BasicBlock *CurBlock = BasicBlock::Create(Ctx, "entry", F);
+ IRBuilder<> Builder(CurBlock);
+
+ PointerType *PtrTy = Builder.getPtrTy();
+ // %DescPtr = call ptr @ppc_get_function_descriptor(ptr noundef @foo)
+ auto *DescPtr = Builder.CreateIntrinsic(/*RetTy*/ PtrTy,
Intrinsic::ppc_get_function_descriptor, {F}, {}, "desc.ptr");
+
+ // %DesctAddr = getelementptr inbounds %struct.Desc_t, ptr %DescPtr, i32
0, i32 0
+ StructType *DescriptorType = StructType::get(PtrTy, PtrTy, PtrTy);
+ auto *DesctAddr = Builder.CreateStructGEP(DescriptorType, DescPtr, 0,
"desc_t.addr");
+
+ // %AddrInDesc = load ptr, ptr %DesctAddr, align 4
+ auto *AddrInDesc = Builder.CreateAlignedLoad(PtrTy, DesctAddr,
DesctAddr->getPointerAlignment(M.getDataLayout()), "addr.in.desc");
+
+ // %OriginalAddr = call ptr @ppc_get_function_entry(ptr noundef @foo) #3
+ auto *OriginalAddr = Builder.CreateIntrinsic(/*RetTy*/ PtrTy,
Intrinsic::ppc_get_function_entry, {F}, {}, "original.addr");
+
+ // %cmp = icmp eq ptr %AddrInDesc, %OriginalAddr
+ auto *CMP = Builder.CreateICmpEQ(AddrInDesc, OriginalAddr);
+
+ // br i1 %cmp, label %resolver, label %end
+ CurBlock = BasicBlock::Create(Ctx, "resolver", F);
+ BasicBlock *FinalBlock = BasicBlock::Create(Ctx, "end", F);
+ Builder.CreateCondBr(CMP, CurBlock, FinalBlock);
+
+ // Emit the 'then' (resolver) code:
+ Builder.SetInsertPoint(CurBlock);
+
+ // resolver:
+ // %ResolvedFunc = call ptr @resolver()
+ // %ResolvedAddr = call ptr @ppc_get_function_entry(ptr %ResolvedFunc)
+ // %4 = ptrtoint ptr %ResolvedAddr to i32
+ // store atomic i32 %4, ptr %desc_t.addr release, align 4
+ Function *ResolverFunc = IFunc.getResolverFunction();
+ auto *ResolvedFunc = Builder.CreateCall(ResolverFunc, ArrayRef<Value *>(),
"resolved.func");
+ auto *ResolvedAddr = Builder.CreateIntrinsic(/*RetTy*/ PtrTy,
Intrinsic::ppc_get_function_entry, {ResolvedFunc}, {}, "resolved.addr");
+ auto *PtrToInt = Builder.CreatePtrToInt(ResolvedAddr,
Builder.getIntPtrTy(M.getDataLayout()));
+ // TODO fix alignment
+ Builder.CreateAlignedStore(PtrToInt, DesctAddr,
MaybeAlign())->setAtomic(AtomicOrdering::Release);
+
+ // br label %if.end
+ Builder.CreateBr(FinalBlock);
+
+ // Emit the continuation block for code after the if.
+ Builder.SetInsertPoint(FinalBlock);
+
+ // %res = musttail call i32 %DescPtr(i32 noundef %a) #3
+ SmallVector<Value *, 10> Args(make_pointer_range(F->args()));
+ CallInst *Result = Builder.CreateCall(F->getFunctionType(), DescPtr, Args,
"res");
+ //Result->setTailCallKind(CallInst::TCK_MustTail);
+
+ // ret i32 %res
+ if (F->getReturnType()->isVoidTy())
+ Builder.CreateRetVoid();
+ else
+ Builder.CreateRet(Result);
+
+ // replace all uses of the ifunc with the newly created function
+ IFunc.replaceAllUsesWith(F);
+
+ std::string name = IFunc.getName().str();
+ IFunc.eraseFromParent();
+ F->setName(name);
+ }
+}
bool llvm::lowerGlobalIFuncUsersAsGlobalCtor(
Module &M, ArrayRef<GlobalIFunc *> FilteredIFuncsToLower) {
SmallVector<GlobalIFunc *, 32> AllIFuncs;
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