[lld] [ELF] Change Ctx::target to unique_ptr (PR #111260)

Fangrui Song via llvm-commits llvm-commits at lists.llvm.org
Sat Oct 5 10:35:04 PDT 2024


https://github.com/MaskRay created https://github.com/llvm/llvm-project/pull/111260

also rename `TargetInfo *getXXXTargetInfo` to `void setXXXTargetInfo` and change it to set `ctx.target`. This ensures that when `ctx` becomes a local variable, two lld invocations will not reuse the function-local static variable.

>From 2a7e1d12ac36dfd0e8f055d5c3b65325dc112b60 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i at maskray.me>
Date: Sat, 5 Oct 2024 09:40:05 -0700
Subject: [PATCH] [ELF] Change Ctx::target to unique_ptr

also rename `TargetInfo *getXXXTargetInfo` to `void setXXXTargetInfo`
and change it to set `ctx.target`. This ensures that when `ctx` becomes
a local variable, two lld invocations will not reuse the function-local
static variable.
---
 lld/ELF/Arch/AArch64.cpp   | 12 +++++-------
 lld/ELF/Arch/AMDGPU.cpp    |  5 +----
 lld/ELF/Arch/ARM.cpp       |  5 +----
 lld/ELF/Arch/AVR.cpp       |  5 +----
 lld/ELF/Arch/Hexagon.cpp   |  5 +----
 lld/ELF/Arch/LoongArch.cpp |  5 ++---
 lld/ELF/Arch/MSP430.cpp    |  5 +----
 lld/ELF/Arch/Mips.cpp      | 18 +++++++++---------
 lld/ELF/Arch/PPC.cpp       |  5 +----
 lld/ELF/Arch/PPC64.cpp     |  5 +----
 lld/ELF/Arch/RISCV.cpp     |  5 +----
 lld/ELF/Arch/SPARCV9.cpp   |  5 +----
 lld/ELF/Arch/SystemZ.cpp   |  5 +----
 lld/ELF/Arch/X86.cpp       | 24 ++++++++++--------------
 lld/ELF/Arch/X86_64.cpp    | 24 ++++++++++--------------
 lld/ELF/Config.h           |  2 +-
 lld/ELF/Driver.cpp         |  4 ++--
 lld/ELF/Target.cpp         | 32 ++++++++++++++++----------------
 lld/ELF/Target.h           | 32 ++++++++++++++++----------------
 19 files changed, 81 insertions(+), 122 deletions(-)

diff --git a/lld/ELF/Arch/AArch64.cpp b/lld/ELF/Arch/AArch64.cpp
index 45d429c915a6ee..2bf9d499b44ffe 100644
--- a/lld/ELF/Arch/AArch64.cpp
+++ b/lld/ELF/Arch/AArch64.cpp
@@ -1208,12 +1208,10 @@ void lld::elf::createTaggedSymbols(const SmallVector<ELFFileBase *, 0> &files) {
   }
 }
 
-TargetInfo *elf::getAArch64TargetInfo(Ctx &ctx) {
+void elf::setAArch64TargetInfo(Ctx &ctx) {
   if ((ctx.arg.andFeatures & GNU_PROPERTY_AARCH64_FEATURE_1_BTI) ||
-      ctx.arg.zPacPlt) {
-    static AArch64BtiPac t(ctx);
-    return &t;
-  }
-  static AArch64 t(ctx);
-  return &t;
+      ctx.arg.zPacPlt)
+    ctx.target.reset(new AArch64BtiPac(ctx));
+  else
+    ctx.target.reset(new AArch64(ctx));
 }
diff --git a/lld/ELF/Arch/AMDGPU.cpp b/lld/ELF/Arch/AMDGPU.cpp
index 29b21f1b953989..99e7cfe6e76ba9 100644
--- a/lld/ELF/Arch/AMDGPU.cpp
+++ b/lld/ELF/Arch/AMDGPU.cpp
@@ -219,7 +219,4 @@ int64_t AMDGPU::getImplicitAddend(const uint8_t *buf, RelType type) const {
   }
 }
 
-TargetInfo *elf::getAMDGPUTargetInfo(Ctx &ctx) {
-  static AMDGPU target(ctx);
-  return ⌖
-}
+void elf::setAMDGPUTargetInfo(Ctx &ctx) { ctx.target.reset(new AMDGPU(ctx)); }
diff --git a/lld/ELF/Arch/ARM.cpp b/lld/ELF/Arch/ARM.cpp
index d22ac540c92a1e..267eeec410ec2c 100644
--- a/lld/ELF/Arch/ARM.cpp
+++ b/lld/ELF/Arch/ARM.cpp
@@ -1533,10 +1533,7 @@ template <typename ELFT> void elf::writeARMCmseImportLib() {
           "': " + toString(std::move(e)));
 }
 
-TargetInfo *elf::getARMTargetInfo(Ctx &ctx) {
-  static ARM target(ctx);
-  return ⌖
-}
+void elf::setARMTargetInfo(Ctx &ctx) { ctx.target.reset(new ARM(ctx)); }
 
 template void elf::writeARMCmseImportLib<ELF32LE>();
 template void elf::writeARMCmseImportLib<ELF32BE>();
diff --git a/lld/ELF/Arch/AVR.cpp b/lld/ELF/Arch/AVR.cpp
index cc2d9fa3daf798..bb88dfe7c7a4c6 100644
--- a/lld/ELF/Arch/AVR.cpp
+++ b/lld/ELF/Arch/AVR.cpp
@@ -267,10 +267,7 @@ void AVR::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
   }
 }
 
-TargetInfo *elf::getAVRTargetInfo(Ctx &ctx) {
-  static AVR target(ctx);
-  return ⌖
-}
+void elf::setAVRTargetInfo(Ctx &ctx) { ctx.target.reset(new AVR(ctx)); }
 
 static uint32_t getEFlags(InputFile *file) {
   return cast<ObjFile<ELF32LE>>(file)->getObj().getHeader().e_flags;
diff --git a/lld/ELF/Arch/Hexagon.cpp b/lld/ELF/Arch/Hexagon.cpp
index d689fc2a152101..ad5a3cd646e65b 100644
--- a/lld/ELF/Arch/Hexagon.cpp
+++ b/lld/ELF/Arch/Hexagon.cpp
@@ -404,7 +404,4 @@ int64_t Hexagon::getImplicitAddend(const uint8_t *buf, RelType type) const {
   }
 }
 
-TargetInfo *elf::getHexagonTargetInfo(Ctx &ctx) {
-  static Hexagon target(ctx);
-  return ⌖
-}
+void elf::setHexagonTargetInfo(Ctx &ctx) { ctx.target.reset(new Hexagon(ctx)); }
diff --git a/lld/ELF/Arch/LoongArch.cpp b/lld/ELF/Arch/LoongArch.cpp
index 3e86488063f0e4..8c4eaf5d75342a 100644
--- a/lld/ELF/Arch/LoongArch.cpp
+++ b/lld/ELF/Arch/LoongArch.cpp
@@ -893,7 +893,6 @@ void LoongArch::finalizeRelax(int passes) const {
   }
 }
 
-TargetInfo *elf::getLoongArchTargetInfo(Ctx &ctx) {
-  static LoongArch target(ctx);
-  return ⌖
+void elf::setLoongArchTargetInfo(Ctx &ctx) {
+  ctx.target.reset(new LoongArch(ctx));
 }
diff --git a/lld/ELF/Arch/MSP430.cpp b/lld/ELF/Arch/MSP430.cpp
index 7563f7cfaa02c6..7eb281bec8d965 100644
--- a/lld/ELF/Arch/MSP430.cpp
+++ b/lld/ELF/Arch/MSP430.cpp
@@ -88,7 +88,4 @@ void MSP430::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
   }
 }
 
-TargetInfo *elf::getMSP430TargetInfo(Ctx &ctx) {
-  static MSP430 target(ctx);
-  return ⌖
-}
+void elf::setMSP430TargetInfo(Ctx &ctx) { ctx.target.reset(new MSP430(ctx)); }
diff --git a/lld/ELF/Arch/Mips.cpp b/lld/ELF/Arch/Mips.cpp
index 0e65df347031ef..a584d2ccc7cdaa 100644
--- a/lld/ELF/Arch/Mips.cpp
+++ b/lld/ELF/Arch/Mips.cpp
@@ -778,23 +778,23 @@ template <class ELFT> bool elf::isMipsPIC(const Defined *sym) {
   return cast<ObjFile<ELFT>>(file)->getObj().getHeader().e_flags & EF_MIPS_PIC;
 }
 
-TargetInfo *elf::getMipsTargetInfo(Ctx &ctx) {
+void elf::setMipsTargetInfo(Ctx &ctx) {
   switch (ctx.arg.ekind) {
   case ELF32LEKind: {
-    static MIPS<ELF32LE> t(ctx);
-    return &t;
+    ctx.target.reset(new MIPS<ELF32LE>(ctx));
+    return;
   }
   case ELF32BEKind: {
-    static MIPS<ELF32BE> t(ctx);
-    return &t;
+    ctx.target.reset(new MIPS<ELF32BE>(ctx));
+    return;
   }
   case ELF64LEKind: {
-    static MIPS<ELF64LE> t(ctx);
-    return &t;
+    ctx.target.reset(new MIPS<ELF64LE>(ctx));
+    return;
   }
   case ELF64BEKind: {
-    static MIPS<ELF64BE> t(ctx);
-    return &t;
+    ctx.target.reset(new MIPS<ELF64BE>(ctx));
+    return;
   }
   default:
     llvm_unreachable("unsupported target");
diff --git a/lld/ELF/Arch/PPC.cpp b/lld/ELF/Arch/PPC.cpp
index 2d6355fac13e63..4a2863f862c5fe 100644
--- a/lld/ELF/Arch/PPC.cpp
+++ b/lld/ELF/Arch/PPC.cpp
@@ -525,7 +525,4 @@ void PPC::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
   }
 }
 
-TargetInfo *elf::getPPCTargetInfo(Ctx &ctx) {
-  static PPC target(ctx);
-  return ⌖
-}
+void elf::setPPCTargetInfo(Ctx &ctx) { ctx.target.reset(new PPC(ctx)); }
diff --git a/lld/ELF/Arch/PPC64.cpp b/lld/ELF/Arch/PPC64.cpp
index da2a5aeed43b06..c284ece9ae1360 100644
--- a/lld/ELF/Arch/PPC64.cpp
+++ b/lld/ELF/Arch/PPC64.cpp
@@ -1750,7 +1750,4 @@ bool PPC64::adjustPrologueForCrossSplitStack(uint8_t *loc, uint8_t *end,
   return true;
 }
 
-TargetInfo *elf::getPPC64TargetInfo(Ctx &ctx) {
-  static PPC64 target(ctx);
-  return ⌖
-}
+void elf::setPPC64TargetInfo(Ctx &ctx) { ctx.target.reset(new PPC64(ctx)); }
diff --git a/lld/ELF/Arch/RISCV.cpp b/lld/ELF/Arch/RISCV.cpp
index f13000fcadec2b..0f09159d8c4f69 100644
--- a/lld/ELF/Arch/RISCV.cpp
+++ b/lld/ELF/Arch/RISCV.cpp
@@ -1328,7 +1328,4 @@ void elf::mergeRISCVAttributesSections(Ctx &) {
                            mergeAttributesSection(sections));
 }
 
-TargetInfo *elf::getRISCVTargetInfo(Ctx &ctx) {
-  static RISCV target(ctx);
-  return ⌖
-}
+void elf::setRISCVTargetInfo(Ctx &ctx) { ctx.target.reset(new RISCV(ctx)); }
diff --git a/lld/ELF/Arch/SPARCV9.cpp b/lld/ELF/Arch/SPARCV9.cpp
index 15c7c9c28b2ed8..aa56ac62402e29 100644
--- a/lld/ELF/Arch/SPARCV9.cpp
+++ b/lld/ELF/Arch/SPARCV9.cpp
@@ -193,7 +193,4 @@ void SPARCV9::writePlt(uint8_t *buf, const Symbol & /*sym*/,
   relocateNoSym(buf + 4, R_SPARC_WDISP19, -(off + 4 - pltEntrySize));
 }
 
-TargetInfo *elf::getSPARCV9TargetInfo(Ctx &ctx) {
-  static SPARCV9 target(ctx);
-  return ⌖
-}
+void elf::setSPARCV9TargetInfo(Ctx &ctx) { ctx.target.reset(new SPARCV9(ctx)); }
diff --git a/lld/ELF/Arch/SystemZ.cpp b/lld/ELF/Arch/SystemZ.cpp
index fc87103165fd4d..02091fbd71d4df 100644
--- a/lld/ELF/Arch/SystemZ.cpp
+++ b/lld/ELF/Arch/SystemZ.cpp
@@ -601,7 +601,4 @@ void SystemZ::relocate(uint8_t *loc, const Relocation &rel,
   }
 }
 
-TargetInfo *elf::getSystemZTargetInfo(Ctx &ctx) {
-  static SystemZ t(ctx);
-  return &t;
-}
+void elf::setSystemZTargetInfo(Ctx &ctx) { ctx.target.reset(new SystemZ(ctx)); }
diff --git a/lld/ELF/Arch/X86.cpp b/lld/ELF/Arch/X86.cpp
index 0a16ca24fcb318..cfbebb0096abbf 100644
--- a/lld/ELF/Arch/X86.cpp
+++ b/lld/ELF/Arch/X86.cpp
@@ -708,21 +708,17 @@ void RetpolineNoPic::writePlt(uint8_t *buf, const Symbol &sym,
   write32le(buf + 22, -off - 26);
 }
 
-TargetInfo *elf::getX86TargetInfo(Ctx &ctx) {
+void elf::setX86TargetInfo(Ctx &ctx) {
   if (ctx.arg.zRetpolineplt) {
-    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) {
-    static IntelIBT t(ctx);
-    return &t;
+    if (ctx.arg.isPic)
+      ctx.target.reset(new RetpolinePic(ctx));
+    else
+      ctx.target.reset(new RetpolineNoPic(ctx));
+    return;
   }
 
-  static X86 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));
 }
diff --git a/lld/ELF/Arch/X86_64.cpp b/lld/ELF/Arch/X86_64.cpp
index d58d0a2961d617..8e491eb85676a1 100644
--- a/lld/ELF/Arch/X86_64.cpp
+++ b/lld/ELF/Arch/X86_64.cpp
@@ -1239,21 +1239,17 @@ void RetpolineZNow::writePlt(uint8_t *buf, const Symbol &sym,
   write32le(buf + 8, ctx.in.plt->getVA() - pltEntryAddr - 12);
 }
 
-TargetInfo *elf::getX86_64TargetInfo(Ctx &ctx) {
+void elf::setX86_64TargetInfo(Ctx &ctx) {
   if (ctx.arg.zRetpolineplt) {
-    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) {
-    static IntelIBT t(ctx);
-    return &t;
+    if (ctx.arg.zNow)
+      ctx.target.reset(new RetpolineZNow(ctx));
+    else
+      ctx.target.reset(new Retpoline(ctx));
+    return;
   }
 
-  static X86_64 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));
 }
diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
index 1d113375143a51..ac6cdf0b07126b 100644
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -542,7 +542,7 @@ struct Ctx {
   Config arg;
   LinkerDriver driver;
   LinkerScript *script;
-  TargetInfo *target;
+  std::unique_ptr<TargetInfo> target;
 
   // These variables are initialized by Writer and should not be used before
   // Writer is initialized.
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 373505a9e965b7..4337be17fe2fca 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -98,7 +98,7 @@ void Ctx::reset() {
   driver.~LinkerDriver();
   new (&driver) LinkerDriver(*this);
   script = nullptr;
-  target = nullptr;
+  target.reset();
 
   bufferStart = nullptr;
   mainPart = nullptr;
@@ -3122,7 +3122,7 @@ 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.
-  ctx.target = getTarget(ctx);
+  setTarget(ctx);
 
   ctx.arg.eflags = ctx.target->calcEFlags();
   // maxPageSize (sometimes called abi page size) is the maximum page size that
diff --git a/lld/ELF/Target.cpp b/lld/ELF/Target.cpp
index d5d11b9549e03f..aae8b545d14fc3 100644
--- a/lld/ELF/Target.cpp
+++ b/lld/ELF/Target.cpp
@@ -45,39 +45,39 @@ std::string lld::toString(RelType type) {
   return std::string(s);
 }
 
-TargetInfo *elf::getTarget(Ctx &ctx) {
+void elf::setTarget(Ctx &ctx) {
   switch (ctx.arg.emachine) {
   case EM_386:
   case EM_IAMCU:
-    return getX86TargetInfo(ctx);
+    return setX86TargetInfo(ctx);
   case EM_AARCH64:
-    return getAArch64TargetInfo(ctx);
+    return setAArch64TargetInfo(ctx);
   case EM_AMDGPU:
-    return getAMDGPUTargetInfo(ctx);
+    return setAMDGPUTargetInfo(ctx);
   case EM_ARM:
-    return getARMTargetInfo(ctx);
+    return setARMTargetInfo(ctx);
   case EM_AVR:
-    return getAVRTargetInfo(ctx);
+    return setAVRTargetInfo(ctx);
   case EM_HEXAGON:
-    return getHexagonTargetInfo(ctx);
+    return setHexagonTargetInfo(ctx);
   case EM_LOONGARCH:
-    return getLoongArchTargetInfo(ctx);
+    return setLoongArchTargetInfo(ctx);
   case EM_MIPS:
-    return getMipsTargetInfo(ctx);
+    return setMipsTargetInfo(ctx);
   case EM_MSP430:
-    return getMSP430TargetInfo(ctx);
+    return setMSP430TargetInfo(ctx);
   case EM_PPC:
-    return getPPCTargetInfo(ctx);
+    return setPPCTargetInfo(ctx);
   case EM_PPC64:
-    return getPPC64TargetInfo(ctx);
+    return setPPC64TargetInfo(ctx);
   case EM_RISCV:
-    return getRISCVTargetInfo(ctx);
+    return setRISCVTargetInfo(ctx);
   case EM_SPARCV9:
-    return getSPARCV9TargetInfo(ctx);
+    return setSPARCV9TargetInfo(ctx);
   case EM_S390:
-    return getSystemZTargetInfo(ctx);
+    return setSystemZTargetInfo(ctx);
   case EM_X86_64:
-    return getX86_64TargetInfo(ctx);
+    return setX86_64TargetInfo(ctx);
   default:
     fatal("unsupported e_machine value: " + Twine(ctx.arg.emachine));
   }
diff --git a/lld/ELF/Target.h b/lld/ELF/Target.h
index f18770dfc424de..74ecd8bf34ded0 100644
--- a/lld/ELF/Target.h
+++ b/lld/ELF/Target.h
@@ -179,21 +179,21 @@ class TargetInfo {
   uint64_t defaultImageBase = 0x10000;
 };
 
-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 &);
+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 &);
 
 struct ErrorPlace {
   InputSectionBase *isec;
@@ -244,7 +244,7 @@ void convertArmInstructionstoBE8(InputSection *sec, uint8_t *buf);
 void createTaggedSymbols(const SmallVector<ELFFileBase *, 0> &files);
 void initSymbolAnchors();
 
-TargetInfo *getTarget(Ctx &);
+void setTarget(Ctx &);
 
 template <class ELFT> bool isMipsPIC(const Defined *sym);
 



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