Revert "[ELF] Change Ctx::target to unique_ptr (#111260)" (#111449)

This patch seems to be breaking the windows build bots.
https://lab.llvm.org/buildbot/#/builders/63/builds/1953

We also see this in Fuchsia's Linux CI:
https://fxbug.dev/372010530

This reverts commit 4ec06b17435e32ece5e1aa2bc8a6d26dbf0bb312.

lld/ELF/Arch/AArch64.cpp

@@ -1208,10 +1208,12 @@ void elf::createTaggedSymbols(Ctx &ctx) {
   }
 }
 
-void elf::setAArch64TargetInfo(Ctx &ctx) {
+TargetInfo *elf::getAArch64TargetInfo(Ctx &ctx) {
   if ((ctx.arg.andFeatures & GNU_PROPERTY_AARCH64_FEATURE_1_BTI) ||
-      ctx.arg.zPacPlt)
-    ctx.target.reset(new AArch64BtiPac(ctx));
-  else
-    ctx.target.reset(new AArch64(ctx));
+      ctx.arg.zPacPlt) {
+    static AArch64BtiPac t(ctx);
+    return &t;
+  }
+  static AArch64 t(ctx);
+  return &t;
 }

lld/ELF/Arch/AMDGPU.cpp

@@ -219,4 +219,7 @@ int64_t AMDGPU::getImplicitAddend(const uint8_t *buf, RelType type) const {
   }
 }
 
-void elf::setAMDGPUTargetInfo(Ctx &ctx) { ctx.target.reset(new AMDGPU(ctx)); }
+TargetInfo *elf::getAMDGPUTargetInfo(Ctx &ctx) {
+  static AMDGPU target(ctx);
+  return ⌖
+}

lld/ELF/Arch/ARM.cpp

@@ -1533,7 +1533,10 @@ template <typename ELFT> void elf::writeARMCmseImportLib(Ctx &ctx) {
           "': " + toString(std::move(e)));
 }
 
-void elf::setARMTargetInfo(Ctx &ctx) { ctx.target.reset(new ARM(ctx)); }
+TargetInfo *elf::getARMTargetInfo(Ctx &ctx) {
+  static ARM target(ctx);
+  return &target;
+}
 
 template void elf::writeARMCmseImportLib<ELF32LE>(Ctx &);
 template void elf::writeARMCmseImportLib<ELF32BE>(Ctx &);

lld/ELF/Arch/AVR.cpp

@@ -267,7 +267,10 @@ void AVR::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
   }
 }
 
-void elf::setAVRTargetInfo(Ctx &ctx) { ctx.target.reset(new AVR(ctx)); }
+TargetInfo *elf::getAVRTargetInfo(Ctx &ctx) {
+  static AVR target(ctx);
+  return ⌖
+}
 
 static uint32_t getEFlags(InputFile *file) {
   return cast<ObjFile<ELF32LE>>(file)->getObj().getHeader().e_flags;

lld/ELF/Arch/Hexagon.cpp

@@ -404,4 +404,7 @@ int64_t Hexagon::getImplicitAddend(const uint8_t *buf, RelType type) const {
   }
 }
 
-void elf::setHexagonTargetInfo(Ctx &ctx) { ctx.target.reset(new Hexagon(ctx)); }
+TargetInfo *elf::getHexagonTargetInfo(Ctx &ctx) {
+  static Hexagon target(ctx);
+  return ⌖
+}

lld/ELF/Arch/LoongArch.cpp

@@ -893,6 +893,7 @@ void LoongArch::finalizeRelax(int passes) const {
   }
 }
 
-void elf::setLoongArchTargetInfo(Ctx &ctx) {
-  ctx.target.reset(new LoongArch(ctx));
+TargetInfo *elf::getLoongArchTargetInfo(Ctx &ctx) {
+  static LoongArch target(ctx);
+  return ⌖
 }

lld/ELF/Arch/MSP430.cpp

@@ -88,4 +88,7 @@ void MSP430::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
   }
 }
 
-void elf::setMSP430TargetInfo(Ctx &ctx) { ctx.target.reset(new MSP430(ctx)); }
+TargetInfo *elf::getMSP430TargetInfo(Ctx &ctx) {
+  static MSP430 target(ctx);
+  return ⌖
+}

lld/ELF/Arch/Mips.cpp

@@ -779,23 +779,23 @@ template <class ELFT> bool elf::isMipsPIC(const Defined *sym) {
   return cast<ObjFile<ELFT>>(file)->getObj().getHeader().e_flags & EF_MIPS_PIC;
 }
 
-void elf::setMipsTargetInfo(Ctx &ctx) {
+TargetInfo *elf::getMipsTargetInfo(Ctx &ctx) {
   switch (ctx.arg.ekind) {
   case ELF32LEKind: {
-    ctx.target.reset(new MIPS<ELF32LE>(ctx));
-    return;
+    static MIPS<ELF32LE> t(ctx);
+    return &t;
   }
   case ELF32BEKind: {
-    ctx.target.reset(new MIPS<ELF32BE>(ctx));
-    return;
+    static MIPS<ELF32BE> t(ctx);
+    return &t;
   }
   case ELF64LEKind: {
-    ctx.target.reset(new MIPS<ELF64LE>(ctx));
-    return;
+    static MIPS<ELF64LE> t(ctx);
+    return &t;
   }
   case ELF64BEKind: {
-    ctx.target.reset(new MIPS<ELF64BE>(ctx));
-    return;
+    static MIPS<ELF64BE> t(ctx);
+    return &t;
   }
   default:
     llvm_unreachable("unsupported target");

lld/ELF/Arch/PPC.cpp

@@ -523,4 +523,7 @@ void PPC::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
   }
 }
 
-void elf::setPPCTargetInfo(Ctx &ctx) { ctx.target.reset(new PPC(ctx)); }
+TargetInfo *elf::getPPCTargetInfo(Ctx &ctx) {
+  static PPC target(ctx);
+  return ⌖
+}

lld/ELF/Arch/PPC64.cpp

@@ -1747,4 +1747,7 @@ bool PPC64::adjustPrologueForCrossSplitStack(uint8_t *loc, uint8_t *end,
   return true;
 }
 
-void elf::setPPC64TargetInfo(Ctx &ctx) { ctx.target.reset(new PPC64(ctx)); }
+TargetInfo *elf::getPPC64TargetInfo(Ctx &ctx) {
+  static PPC64 target(ctx);
+  return ⌖
+}

lld/ELF/Arch/RISCV.cpp

@@ -1329,4 +1329,7 @@ void elf::mergeRISCVAttributesSections(Ctx &ctx) {
                            mergeAttributesSection(ctx, sections));
 }
 
-void elf::setRISCVTargetInfo(Ctx &ctx) { ctx.target.reset(new RISCV(ctx)); }
+TargetInfo *elf::getRISCVTargetInfo(Ctx &ctx) {
+  static RISCV target(ctx);
+  return ⌖
+}

lld/ELF/Arch/SPARCV9.cpp

@@ -193,4 +193,7 @@ void SPARCV9::writePlt(uint8_t *buf, const Symbol & /*sym*/,
   relocateNoSym(buf + 4, R_SPARC_WDISP19, -(off + 4 - pltEntrySize));
 }
 
-void elf::setSPARCV9TargetInfo(Ctx &ctx) { ctx.target.reset(new SPARCV9(ctx)); }
+TargetInfo *elf::getSPARCV9TargetInfo(Ctx &ctx) {
+  static SPARCV9 target(ctx);
+  return ⌖
+}

lld/ELF/Arch/SystemZ.cpp

@@ -600,4 +600,7 @@ void SystemZ::relocate(uint8_t *loc, const Relocation &rel,
   }
 }
 
-void elf::setSystemZTargetInfo(Ctx &ctx) { ctx.target.reset(new SystemZ(ctx)); }
+TargetInfo *elf::getSystemZTargetInfo(Ctx &ctx) {
+  static SystemZ t(ctx);
+  return &t;
+}

lld/ELF/Arch/X86.cpp

@@ -706,17 +706,21 @@ void RetpolineNoPic::writePlt(uint8_t *buf, const Symbol &sym,
   write32le(buf + 22, -off - 26);
 }
 
-void elf::setX86TargetInfo(Ctx &ctx) {
+TargetInfo *elf::getX86TargetInfo(Ctx &ctx) {
   if (ctx.arg.zRetpolineplt) {
-    if (ctx.arg.isPic)
-      ctx.target.reset(new RetpolinePic(ctx));
-    else
-      ctx.target.reset(new RetpolineNoPic(ctx));
-    return;
+    if (ctx.arg.isPic) {
+      static RetpolinePic t(ctx);
+      return &t;
+    }
+    static RetpolineNoPic t(ctx);
+    return &t;
   }
 
-  if (ctx.arg.andFeatures & GNU_PROPERTY_X86_FEATURE_1_IBT)
-    ctx.target.reset(new IntelIBT(ctx));
-  else
-    ctx.target.reset(new X86(ctx));
+  if (ctx.arg.andFeatures & GNU_PROPERTY_X86_FEATURE_1_IBT) {
+    static IntelIBT t(ctx);
+    return &t;
+  }
+
+  static X86 t(ctx);
+  return &t;
 }

lld/ELF/Arch/X86_64.cpp

@@ -1237,17 +1237,21 @@ void RetpolineZNow::writePlt(uint8_t *buf, const Symbol &sym,
   write32le(buf + 8, ctx.in.plt->getVA() - pltEntryAddr - 12);
 }
 
-void elf::setX86_64TargetInfo(Ctx &ctx) {
+TargetInfo *elf::getX86_64TargetInfo(Ctx &ctx) {
   if (ctx.arg.zRetpolineplt) {
-    if (ctx.arg.zNow)
-      ctx.target.reset(new RetpolineZNow(ctx));
-    else
-      ctx.target.reset(new Retpoline(ctx));
-    return;
+    if (ctx.arg.zNow) {
+      static RetpolineZNow t(ctx);
+      return &t;
+    }
+    static Retpoline t(ctx);
+    return &t;
   }
 
-  if (ctx.arg.andFeatures & GNU_PROPERTY_X86_FEATURE_1_IBT)
-    ctx.target.reset(new IntelIBT(ctx));
-  else
-    ctx.target.reset(new X86_64(ctx));
+  if (ctx.arg.andFeatures & GNU_PROPERTY_X86_FEATURE_1_IBT) {
+    static IntelIBT t(ctx);
+    return &t;
+  }
+
+  static X86_64 t(ctx);
+  return &t;
 }

lld/ELF/Config.h

@@ -545,7 +545,7 @@ struct Ctx {
   Config arg;
   LinkerDriver driver;
   LinkerScript *script;
-  std::unique_ptr<TargetInfo> target;
+  TargetInfo *target;
 
   // These variables are initialized by Writer and should not be used before
   // Writer is initialized.

lld/ELF/Driver.cpp

@@ -99,7 +99,7 @@ void Ctx::reset() {
   driver.~LinkerDriver();
   new (&driver) LinkerDriver(*this);
   script = nullptr;
-  target.reset();
+  target = nullptr;
 
   bufferStart = nullptr;
   mainPart = nullptr;
@@ -3126,7 +3126,7 @@ template <class ELFT> void LinkerDriver::link(opt::InputArgList &args) {
   // The Target instance handles target-specific stuff, such as applying
   // relocations or writing a PLT section. It also contains target-dependent
   // values such as a default image base address.
-  setTarget(ctx);
+  ctx.target = getTarget(ctx);
 
   ctx.arg.eflags = ctx.target->calcEFlags();
   // maxPageSize (sometimes called abi page size) is the maximum page size that

lld/ELF/Target.cpp

@@ -45,39 +45,39 @@ std::string lld::toString(RelType type) {
   return std::string(s);
 }
 
-void elf::setTarget(Ctx &ctx) {
+TargetInfo *elf::getTarget(Ctx &ctx) {
   switch (ctx.arg.emachine) {
   case EM_386:
   case EM_IAMCU:
-    return setX86TargetInfo(ctx);
+    return getX86TargetInfo(ctx);
   case EM_AARCH64:
-    return setAArch64TargetInfo(ctx);
+    return getAArch64TargetInfo(ctx);
   case EM_AMDGPU:
-    return setAMDGPUTargetInfo(ctx);
+    return getAMDGPUTargetInfo(ctx);
   case EM_ARM:
-    return setARMTargetInfo(ctx);
+    return getARMTargetInfo(ctx);
   case EM_AVR:
-    return setAVRTargetInfo(ctx);
+    return getAVRTargetInfo(ctx);
   case EM_HEXAGON:
-    return setHexagonTargetInfo(ctx);
+    return getHexagonTargetInfo(ctx);
   case EM_LOONGARCH:
-    return setLoongArchTargetInfo(ctx);
+    return getLoongArchTargetInfo(ctx);
   case EM_MIPS:
-    return setMipsTargetInfo(ctx);
+    return getMipsTargetInfo(ctx);
   case EM_MSP430:
-    return setMSP430TargetInfo(ctx);
+    return getMSP430TargetInfo(ctx);
   case EM_PPC:
-    return setPPCTargetInfo(ctx);
+    return getPPCTargetInfo(ctx);
   case EM_PPC64:
-    return setPPC64TargetInfo(ctx);
+    return getPPC64TargetInfo(ctx);
   case EM_RISCV:
-    return setRISCVTargetInfo(ctx);
+    return getRISCVTargetInfo(ctx);
   case EM_SPARCV9:
-    return setSPARCV9TargetInfo(ctx);
+    return getSPARCV9TargetInfo(ctx);
   case EM_S390:
-    return setSystemZTargetInfo(ctx);
+    return getSystemZTargetInfo(ctx);
   case EM_X86_64:
-    return setX86_64TargetInfo(ctx);
+    return getX86_64TargetInfo(ctx);
   default:
     fatal("unsupported e_machine value: " + Twine(ctx.arg.emachine));
   }

lld/ELF/Target.h

@@ -179,21 +179,21 @@ protected:
   uint64_t defaultImageBase = 0x10000;
 };
 
-void setAArch64TargetInfo(Ctx &);
-void setAMDGPUTargetInfo(Ctx &);
-void setARMTargetInfo(Ctx &);
-void setAVRTargetInfo(Ctx &);
-void setHexagonTargetInfo(Ctx &);
-void setLoongArchTargetInfo(Ctx &);
-void setMSP430TargetInfo(Ctx &);
-void setMipsTargetInfo(Ctx &);
-void setPPC64TargetInfo(Ctx &);
-void setPPCTargetInfo(Ctx &);
-void setRISCVTargetInfo(Ctx &);
-void setSPARCV9TargetInfo(Ctx &);
-void setSystemZTargetInfo(Ctx &);
-void setX86TargetInfo(Ctx &);
-void setX86_64TargetInfo(Ctx &);
+TargetInfo *getAArch64TargetInfo(Ctx &);
+TargetInfo *getAMDGPUTargetInfo(Ctx &);
+TargetInfo *getARMTargetInfo(Ctx &);
+TargetInfo *getAVRTargetInfo(Ctx &);
+TargetInfo *getHexagonTargetInfo(Ctx &);
+TargetInfo *getLoongArchTargetInfo(Ctx &);
+TargetInfo *getMSP430TargetInfo(Ctx &);
+TargetInfo *getMipsTargetInfo(Ctx &);
+TargetInfo *getPPC64TargetInfo(Ctx &);
+TargetInfo *getPPCTargetInfo(Ctx &);
+TargetInfo *getRISCVTargetInfo(Ctx &);
+TargetInfo *getSPARCV9TargetInfo(Ctx &);
+TargetInfo *getSystemZTargetInfo(Ctx &);
+TargetInfo *getX86TargetInfo(Ctx &);
+TargetInfo *getX86_64TargetInfo(Ctx &);
 
 struct ErrorPlace {
   InputSectionBase *isec;
@@ -251,7 +251,7 @@ void convertArmInstructionstoBE8(InputSection *sec, uint8_t *buf);
 void createTaggedSymbols(Ctx &);
 void initSymbolAnchors(Ctx &);
 
-void setTarget(Ctx &);
+TargetInfo *getTarget(Ctx &);
 
 template <class ELFT> bool isMipsPIC(const Defined *sym);