https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/178698
Backport 41567d8ec21b79e16c9f1223e2df23c65c1bc195 Requested by: @amy-kwan >From a94d025bd6ae1b6e80ee4609c76503088cd20ca9 Mon Sep 17 00:00:00 2001 From: Amy Kwan <[email protected]> Date: Fri, 23 Jan 2026 13:29:08 -0500 Subject: [PATCH] [SystemZ] Implement ctor/dtor emission via @@SQINIT and .xtor sections (#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. (cherry picked from commit 41567d8ec21b79e16c9f1223e2df23c65c1bc195) --- .../CodeGen/TargetLoweringObjectFileImpl.h | 1 + llvm/include/llvm/MC/MCGOFFAttributes.h | 1 + .../CodeGen/TargetLoweringObjectFileImpl.cpp | 36 +++++++++++ llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp | 63 +++++++++++++++++++ llvm/lib/Target/SystemZ/SystemZAsmPrinter.h | 2 + llvm/test/CodeGen/SystemZ/zos_sinit.ll | 34 ++++++++++ 6 files changed, 137 insertions(+) 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..9f271dd502b24 100644 --- a/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h +++ b/llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h @@ -331,6 +331,7 @@ class TargetLoweringObjectFileGOFF : public TargetLoweringObjectFile { const TargetMachine &TM) const override; MCSection *getSectionForLSDA(const Function &F, const MCSymbol &FnSym, const TargetMachine &TM) const override; + MCSection *getStaticXtorSection(unsigned Priority) const; }; } // 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/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp index 5edbc4caf3fae..6bbad68c26699 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 +2861,35 @@ MCSection *TargetLoweringObjectFileGOFF::SelectSectionForGlobal( } return TextSection; } + +MCSection * +TargetLoweringObjectFileGOFF::getStaticXtorSection(unsigned Priority) const { + // XL C/C++ 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(); + + MCContext &Ctx = getContext(); + 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; +} diff --git a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp index a5fe29095503b..33e48f8ff1511 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" @@ -1012,6 +1013,68 @@ 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()) + return AsmPrinter::emitXXStructorList(DL, List, IsCtor); + + SmallVector<Structor, 8> Structors; + preprocessXXStructorList(DL, List, Structors); + if (Structors.empty()) + return; + + const Align Align = llvm::Align(4); + const TargetLoweringObjectFileGOFF &Obj = + static_cast<const TargetLoweringObjectFileGOFF &>(getObjFileLowering()); + for (Structor &S : Structors) { + MCSectionGOFF *Section = + static_cast<MCSectionGOFF *>(Obj.getStaticXtorSection(S.Priority)); + OutStreamer->switchSection(Section); + if (OutStreamer->getCurrentSection() != OutStreamer->getPreviousSection()) + emitAlignment(Align); + + // The priority is provided as an input to getStaticXtorSection(), and is + // recalculated within that function as `Prio` going to going into the + // PR section. + // This priority retrieved via the `SortKey` below is the recalculated + // Priority. + 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; + + MCSectionGOFF *ADASection = + static_cast<MCSectionGOFF *>(Obj.getADASection()); + assert(ADASection && "ADA section must exist for GOFF targets!"); + const MCSymbol *ADASym = ADASection->getBeginSymbol(); + assert(ADASym && "ADA symbol should already be set!"); + + ADAFuncRefExpr = MCBinaryExpr::createAdd( + MCSpecifierExpr::create(MCSymbolRefExpr::create(ADASym, OutContext), + SystemZ::S_QCon, OutContext), + MCConstantExpr::create(ADATable.insert(Symbol, SlotKind), 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; diff --git a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h index cb101e472824f..663a0b2b295f9 100644 --- a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h +++ b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h @@ -108,6 +108,8 @@ class LLVM_LIBRARY_VISIBILITY SystemZAsmPrinter : public 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..447dec345e175 --- /dev/null +++ b/llvm/test/CodeGen/SystemZ/zos_sinit.ll @@ -0,0 +1,34 @@ +; 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 XL4'7FFF0017' +; Check direct relocation and low bit on ctor. +; CHECK: DC AD(QD(stdin#S)+XL8'0') +; CHECK: DC XL8'0000000000000000' +; 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
