https://github.com/amy-kwan created https://github.com/llvm/llvm-project/pull/171476
This patch implements support for constructors/destructors by introducing the `@@SQINIT` section and emitting `.xtor.<priority>` sections within the SystemZ AsmPrinter and in the GOFF object lowering layer. Improvements to ADA descriptor handling is also done within this change. >From 26283a60dfcf87d59d7939df10233c1a033b89f4 Mon Sep 17 00:00:00 2001 From: Amy Kwan <[email protected]> Date: Fri, 21 Nov 2025 13:54:48 -0500 Subject: [PATCH] [SystemZ] Implement ctor/dtor emission via @@SQINIT and .xtor sections This patch implements support for constructors/destructors by introducing the @@SQINIT section and emitting .xtor.<priority> sections within the SystemZ AsmPrinter and in the GOFF object lowering layer. Improvements to ADA descriptor handling is also done within this change. --- .../CodeGen/TargetLoweringObjectFileImpl.h | 4 + llvm/include/llvm/MC/MCGOFFAttributes.h | 1 + llvm/include/llvm/MC/MCSectionGOFF.h | 12 +++ .../CodeGen/TargetLoweringObjectFileImpl.cpp | 49 ++++++++++ llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp | 89 ++++++++++++++++--- llvm/lib/Target/SystemZ/SystemZAsmPrinter.h | 14 +-- llvm/test/CodeGen/SystemZ/zos_sinit.ll | 36 ++++++++ 7 files changed, 190 insertions(+), 15 deletions(-) create mode 100644 llvm/test/CodeGen/SystemZ/zos_sinit.ll diff --git a/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h b/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h index fe450b3c1a3a2..8f1f20f7ead0c 100644 --- a/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h +++ b/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h @@ -331,6 +331,10 @@ class TargetLoweringObjectFileGOFF : public TargetLoweringObjectFile { const TargetMachine &TM) const override; MCSection *getSectionForLSDA(const Function &F, const MCSymbol &FnSym, const TargetMachine &TM) const override; + MCSection *getStaticCtorSection(unsigned Priority, + const MCSymbol *KeySym) const override; + MCSection *getStaticDtorSection(unsigned Priority, + const MCSymbol *KeySym) const override; }; } // end namespace llvm diff --git a/llvm/include/llvm/MC/MCGOFFAttributes.h b/llvm/include/llvm/MC/MCGOFFAttributes.h index e771f36f35346..b1c6d73e41f9f 100644 --- a/llvm/include/llvm/MC/MCGOFFAttributes.h +++ b/llvm/include/llvm/MC/MCGOFFAttributes.h @@ -94,6 +94,7 @@ constexpr StringLiteral CLASS_CODE = "C_CODE64"; constexpr StringLiteral CLASS_WSA = "C_WSA64"; constexpr StringLiteral CLASS_DATA = "C_DATA64"; constexpr StringLiteral CLASS_PPA2 = "C_@@QPPA2"; +constexpr StringLiteral CLASS_SINIT = "C_@@SQINIT"; } // namespace GOFF } // namespace llvm diff --git a/llvm/include/llvm/MC/MCSectionGOFF.h b/llvm/include/llvm/MC/MCSectionGOFF.h index 2136148368fbd..261bee5e57d96 100644 --- a/llvm/include/llvm/MC/MCSectionGOFF.h +++ b/llvm/include/llvm/MC/MCSectionGOFF.h @@ -27,6 +27,13 @@ namespace llvm { class MCExpr; class LLVM_ABI MCSectionGOFF final : public MCSection { +public: + enum XtorType { NotXtor, CtorType, DtorType }; + +private: + // ctor/dtor section related - i.e. C_@@S[Q]INIT + enum XtorType XtorSectionType = NotXtor; + // Parent of this section. Implies that the parent is emitted first. MCSectionGOFF *Parent; @@ -115,6 +122,11 @@ class LLVM_ABI MCSectionGOFF final : public MCSection { bool requiresNonZeroLength() const { return RequiresNonZeroLength; } void setName(StringRef SectionName) { Name = SectionName; } + + bool isXtorSection() const { return XtorSectionType != NotXtor; } + void setXtorSectionType(XtorType Value) { XtorSectionType = Value; } + XtorType getXtorSectionType() const { return XtorSectionType; } + }; } // end namespace llvm diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp index 5edbc4caf3fae..4ede966702335 100644 --- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp +++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp @@ -2794,6 +2794,10 @@ void TargetLoweringObjectFileGOFF::getModuleMetadata(Module &M) { TextLD->setWeak(false); TextLD->setADA(ADAPR); TextSection->setBeginSymbol(TextLD); + // Initialize the label for the ADA section. + MCSymbolGOFF *ADASym = static_cast<MCSymbolGOFF *>( + getContext().getOrCreateSymbol(ADAPR->getName())); + ADAPR->setBeginSymbol(ADASym); } MCSection *TargetLoweringObjectFileGOFF::getExplicitSectionGlobal( @@ -2857,3 +2861,48 @@ MCSection *TargetLoweringObjectFileGOFF::SelectSectionForGlobal( } return TextSection; } + +static MCSectionGOFF *getStaticStructorSectionGOFF(MCContext &Ctx, + const MCSection *TextSection, + bool IsCtor, + unsigned Priority) { + // xl compilers on z/OS support priorities from min-int to max-int, with + // sinit as source priority 0. For clang, sinit has source priority 65535. + // For GOFF, the priority sortkey field is an unsigned value. So, we + // add min-int to get sorting to work properly but also subtract the + // clang sinit (65535) value so internally xl sinit and clang sinit have + // the same unsigned GOFF priority sortkey field value (i.e. 0x80000000). + static constexpr const uint32_t ClangDefaultSinitPriority = 65535; + uint32_t Prio = Priority + (0x80000000 - ClangDefaultSinitPriority); + + std::string Name(".xtor"); + if (Priority != ClangDefaultSinitPriority) + Name = llvm::Twine(Name).concat(".").concat(llvm::utostr(Priority)).str(); + + MCSectionGOFF *SInit = Ctx.getGOFFSection( + SectionKind::getMetadata(), GOFF::CLASS_SINIT, + GOFF::EDAttr{false, GOFF::ESD_RMODE_64, GOFF::ESD_NS_Parts, + GOFF::ESD_TS_ByteOriented, GOFF::ESD_BA_Merge, + GOFF::ESD_LB_Initial, GOFF::ESD_RQ_0, + GOFF::ESD_ALIGN_Doubleword}, + static_cast<const MCSectionGOFF *>(TextSection)->getParent()); + + MCSectionGOFF *Xtor = Ctx.getGOFFSection( + SectionKind::getData(), Name, + GOFF::PRAttr{true, GOFF::ESD_EXE_DATA, GOFF::ESD_LT_XPLink, + GOFF::ESD_BSC_Section, Prio}, + SInit); + return Xtor; +} + +MCSection *TargetLoweringObjectFileGOFF::getStaticCtorSection( + unsigned Priority, const MCSymbol *KeySym) const { + return getStaticStructorSectionGOFF(getContext(), TextSection, true, + Priority); +} + +MCSection *TargetLoweringObjectFileGOFF::getStaticDtorSection( + unsigned Priority, const MCSymbol *KeySym) const { + return getStaticStructorSectionGOFF(getContext(), TextSection, false, + Priority); +} diff --git a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp index 414d68e2678ed..5d43eb0830746 100644 --- a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp +++ b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp @@ -31,6 +31,7 @@ #include "llvm/MC/MCInstBuilder.h" #include "llvm/MC/MCSectionELF.h" #include "llvm/MC/MCStreamer.h" +#include "llvm/MC/MCSymbolGOFF.h" #include "llvm/MC/TargetRegistry.h" #include "llvm/Support/Chrono.h" #include "llvm/Support/Compiler.h" @@ -170,13 +171,14 @@ void SystemZAsmPrinter::emitCallInformation(CallType CT) { .addReg(SystemZMC::GR64Regs[static_cast<unsigned>(CT)])); } -uint32_t SystemZAsmPrinter::AssociatedDataAreaTable::insert(const MCSymbol *Sym, - unsigned SlotKind) { +std::pair<const MCSymbol *, uint32_t> +SystemZAsmPrinter::AssociatedDataAreaTable::insert(const MCSymbol *Sym, + unsigned SlotKind) { auto Key = std::make_pair(Sym, SlotKind); - auto It = Displacements.find(Key); + auto *It = Displacements.find(Key); if (It != Displacements.end()) - return (*It).second; + return std::pair(Sym, (*It).second); // Determine length of descriptor. uint32_t Length; @@ -189,18 +191,23 @@ uint32_t SystemZAsmPrinter::AssociatedDataAreaTable::insert(const MCSymbol *Sym, break; } + // Language Environment DLL logic requires function descriptors, for + // imported functions, that are placed in the ADA to be 8 byte aligned. + if (SlotKind == SystemZII::MO_ADA_DIRECT_FUNC_DESC) + NextDisplacement = alignTo(NextDisplacement, 8); uint32_t Displacement = NextDisplacement; Displacements[std::make_pair(Sym, SlotKind)] = NextDisplacement; NextDisplacement += Length; - return Displacement; + return std::pair(Sym, Displacement); } -uint32_t +std::pair<const MCSymbol *, uint32_t> SystemZAsmPrinter::AssociatedDataAreaTable::insert(const MachineOperand MO) { MCSymbol *Sym; if (MO.getType() == MachineOperand::MO_GlobalAddress) { const GlobalValue *GV = MO.getGlobal(); + assert(GV->hasName() && "Cannot put unnamed value in ADA"); Sym = MO.getParent()->getMF()->getTarget().getSymbol(GV); assert(Sym && "No symbol"); } else if (MO.getType() == MachineOperand::MO_ExternalSymbol) { @@ -347,7 +354,9 @@ void SystemZAsmPrinter::emitInstruction(const MachineInstr *MI) { case SystemZ::ADA_ENTRY: { const SystemZSubtarget &Subtarget = MF->getSubtarget<SystemZSubtarget>(); const SystemZInstrInfo *TII = Subtarget.getInstrInfo(); - uint32_t Disp = ADATable.insert(MI->getOperand(1)); + const MCSymbol *Sym; + uint32_t Disp; + std::tie(Sym, Disp) = ADATable.insert(MI->getOperand(1)); Register TargetReg = MI->getOperand(0).getReg(); Register ADAReg = MI->getOperand(2).getReg(); @@ -1012,6 +1021,60 @@ void SystemZAsmPrinter::emitMachineConstantPoolValue( OutStreamer->emitValue(Expr, Size); } +// Emit the ctor or dtor list taking into account the init priority. +void SystemZAsmPrinter::emitXXStructorList(const DataLayout &DL, + const Constant *List, + bool IsCtor) { + if (TM.getTargetTriple().isOSBinFormatGOFF()) + AsmPrinter::emitXXStructorList(DL, List, IsCtor); + + SmallVector<Structor, 8> Structors; + preprocessXXStructorList(DL, List, Structors); + if (Structors.empty()) + return; + + const Align Align = llvm::Align(4); + const TargetLoweringObjectFile &Obj = getObjFileLowering(); + for (Structor &S : Structors) { + MCSection *OutputSection = + (IsCtor ? Obj.getStaticCtorSection(S.Priority, nullptr) + : Obj.getStaticDtorSection(S.Priority, nullptr)); + OutStreamer->switchSection(OutputSection); + if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection()) + emitAlignment(Align); + + const MCSectionGOFF *Section = + static_cast<const MCSectionGOFF *>(getCurrentSection()); + uint32_t XtorPriority = Section->getPRAttributes().SortKey; + + const GlobalValue *GV = dyn_cast<GlobalValue>(S.Func->stripPointerCasts()); + assert(GV && "C++ xxtor pointer was not a GlobalValue!"); + MCSymbolGOFF *Symbol = static_cast<MCSymbolGOFF *>(getSymbol(GV)); + + // @@SQINIT entry: { unsigned prio; void (*ctor)(); void (*dtor)(); } + + unsigned PointerSizeInBytes = DL.getPointerSize(); + + auto &Ctx = OutStreamer->getContext(); + const MCExpr *ADAFuncRefExpr; + unsigned SlotKind = SystemZII::MO_ADA_DIRECT_FUNC_DESC; + ADAFuncRefExpr = MCBinaryExpr::createAdd( + MCSpecifierExpr::create(MCSymbolRefExpr::create(ADASym, OutContext), + SystemZ::S_QCon, OutContext), + MCConstantExpr::create(ADATable.insert(Symbol, SlotKind).second, Ctx), + Ctx); + + emitInt32(XtorPriority); + if (IsCtor) { + OutStreamer->emitValue(ADAFuncRefExpr, PointerSizeInBytes); + OutStreamer->emitIntValue(0, PointerSizeInBytes); + } else { + OutStreamer->emitIntValue(0, PointerSizeInBytes); + OutStreamer->emitValue(ADAFuncRefExpr, PointerSizeInBytes); + } + } +} + static void printFormattedRegName(const MCAsmInfo *MAI, unsigned RegNo, raw_ostream &OS) { const char *RegName; @@ -1536,13 +1599,17 @@ void SystemZAsmPrinter::emitPPA1(MCSymbol *FnEndSym) { OutStreamer->AddComment("Flags"); OutStreamer->emitInt32(0); // LSDA field is a WAS offset OutStreamer->AddComment("Personality routine"); - OutStreamer->emitInt64(ADATable.insert( - PersonalityRoutine, SystemZII::MO_ADA_INDIRECT_FUNC_DESC)); + // Store only offset of function descriptor + OutStreamer->emitInt64( + ADATable + .insert(PersonalityRoutine, SystemZII::MO_ADA_INDIRECT_FUNC_DESC) + .second); OutStreamer->AddComment("LSDA location"); + // Store only offset of LSDA MCSymbol *GCCEH = MF->getContext().getOrCreateSymbol( Twine("GCC_except_table") + Twine(MF->getFunctionNumber())); OutStreamer->emitInt64( - ADATable.insert(GCCEH, SystemZII::MO_ADA_DATA_SYMBOL_ADDR)); + ADATable.insert(GCCEH, SystemZII::MO_ADA_DATA_SYMBOL_ADDR).second); } // Emit name length and name optional section (0x01 of flags 4) @@ -1561,6 +1628,8 @@ void SystemZAsmPrinter::emitStartOfAsmFile(Module &M) { } void SystemZAsmPrinter::emitPPA2(Module &M) { + ADASym = getObjFileLowering().getADASection()->getBeginSymbol(); + OutStreamer->pushSection(); OutStreamer->switchSection(getObjFileLowering().getTextSection(), GOFF::SK_PPA2); diff --git a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h index cb101e472824f..19b517f82d658 100644 --- a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h +++ b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h @@ -31,6 +31,7 @@ class LLVM_LIBRARY_VISIBILITY SystemZAsmPrinter : public AsmPrinter { MCSymbol *CurrentFnPPA1Sym; // PPA1 Symbol. MCSymbol *CurrentFnEPMarkerSym; // Entry Point Marker. MCSymbol *PPA2Sym; + MCSymbol *ADASym; SystemZTargetStreamer *getTargetStreamer() { MCTargetStreamer *TS = OutStreamer->getTargetStreamer(); @@ -73,16 +74,17 @@ class LLVM_LIBRARY_VISIBILITY SystemZAsmPrinter : public AsmPrinter { /// @brief Add a function descriptor to the ADA. /// @param MI Pointer to an ADA_ENTRY instruction. - /// @return The displacement of the descriptor into the ADA. - uint32_t insert(const MachineOperand MO); + /// @return The symbol and displacement of the descriptor into the ADA. + std::pair<const MCSymbol *, uint32_t> insert(const MachineOperand MO); /// @brief Get the displacement into associated data area (ADA) for a name. /// If no displacement is already associated with the name, assign one and /// return it. /// @param Sym The symbol for which the displacement should be returned. /// @param SlotKind The ADA type. - /// @return The displacement of the descriptor into the ADA. - uint32_t insert(const MCSymbol *Sym, unsigned SlotKind); + /// @return The symbol and displacement of the descriptor into the ADA. + std::pair<const MCSymbol *, uint32_t> insert(const MCSymbol *Sym, + unsigned SlotKind); /// Get the table of GOFF displacements. This is 'const' since it should /// never be modified by anything except the APIs on this class. @@ -101,13 +103,15 @@ class LLVM_LIBRARY_VISIBILITY SystemZAsmPrinter : public AsmPrinter { public: SystemZAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer) : AsmPrinter(TM, std::move(Streamer), ID), CurrentFnPPA1Sym(nullptr), - CurrentFnEPMarkerSym(nullptr), PPA2Sym(nullptr), + CurrentFnEPMarkerSym(nullptr), PPA2Sym(nullptr), ADASym(nullptr), ADATable(TM.getPointerSize(0)) {} // Override AsmPrinter. StringRef getPassName() const override { return "SystemZ Assembly Printer"; } void emitInstruction(const MachineInstr *MI) override; void emitMachineConstantPoolValue(MachineConstantPoolValue *MCPV) override; + void emitXXStructorList(const DataLayout &DL, const Constant *List, + bool IsCtor) override; void emitEndOfAsmFile(Module &M) override; bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo, const char *ExtraCode, raw_ostream &OS) override; diff --git a/llvm/test/CodeGen/SystemZ/zos_sinit.ll b/llvm/test/CodeGen/SystemZ/zos_sinit.ll new file mode 100644 index 0000000000000..036ec71466079 --- /dev/null +++ b/llvm/test/CodeGen/SystemZ/zos_sinit.ll @@ -0,0 +1,36 @@ +; RUN: llc -emit-gnuas-syntax-on-zos=false < %s -mtriple=s390x-ibm-zos | \ +; RUN: FileCheck --check-prefixes=CHECK %s + [email protected]_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 22, ptr @cfuncctor, ptr null }] [email protected]_dtors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 22, ptr @cfuncdtor, ptr null }] + +; Check for presence of C_@@SQINIT: +; CHECK: .xtor.22 +; CHECK: DC AD(cfuncctor) +; CHECK: DC XL4'7FFF0017' +; Check direct relocation and low bit on ctor. +; CHECK: DC AD(QD(stdin#S)+XL8'0') +; CHECK: DC XL8'0000000000000000' +; CHECK: DC AD(cfuncdtor) +; CHECK: DC XL4'7FFF0017' +; CHECK: DC XL8'0000000000000000' +; Check direct relocation and low bit on dtor. +; CHECK: DC AD(QD(stdin#S)+XL8'16') + +; Check for function descriptors in ADA section: +; CHECK: * Offset 0 function descriptor of cfuncctor +; CHECK: DC RD(cfuncctor) +; CHECK: DC VD(cfuncctor) +; CHECK: * Offset 16 function descriptor of cfuncdtor +; CHECK: DC RD(cfuncdtor) +; CHECK: DC VD(cfuncdtor) + +define hidden void @cfuncctor() { +entry: + ret void +} + +define hidden void @cfuncdtor() { +entry: + ret void +} _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
