ELF: Split relocateAlloc to relocateAlloc and relocateEh. NFC

MaskRay · web-flow · commit fd5d7c504850 · 2025-09-22T09:08:12.000-07:00
relocateAlloc can be called with either InputSection (including SyntheticSection like GotSection) or EhInputSection. Introduce relocateEh so that we can remove some boilerplate and replace relocateAlloc's parameter type with `InputSection`. Pull Request: llvm/llvm-project#160031
diff --git a/lld/ELF/Arch/AArch64.cpp b/lld/ELF/Arch/AArch64.cpp
@@ -82,7 +82,7 @@ class AArch64 : public TargetInfo {
   void relocate(uint8_t *loc, const Relocation &rel,
                 uint64_t val) const override;
   RelExpr adjustTlsExpr(RelType type, RelExpr expr) const override;
-  void relocateAlloc(InputSectionBase &sec, uint8_t *buf) const override;
+  void relocateAlloc(InputSection &sec, uint8_t *buf) const override;
   void applyBranchToBranchOpt() const override;
 
 private:
@@ -939,12 +939,8 @@ static bool needsGotForMemtag(const Relocation &rel) {
   return rel.sym->isTagged() && needsGot(rel.expr);
 }
 
-void AArch64::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
-  uint64_t secAddr = sec.getOutputSection()->addr;
-  if (auto *s = dyn_cast<InputSection>(&sec))
-    secAddr += s->outSecOff;
-  else if (auto *ehIn = dyn_cast<EhInputSection>(&sec))
-    secAddr += ehIn->getParent()->outSecOff;
+void AArch64::relocateAlloc(InputSection &sec, uint8_t *buf) const {
+  uint64_t secAddr = sec.getOutputSection()->addr + sec.outSecOff;
   AArch64Relaxer relaxer(ctx, sec.relocs());
   for (size_t i = 0, size = sec.relocs().size(); i != size; ++i) {
     const Relocation &rel = sec.relocs()[i];
diff --git a/lld/ELF/Arch/LoongArch.cpp b/lld/ELF/Arch/LoongArch.cpp
@@ -41,7 +41,7 @@ class LoongArch final : public TargetInfo {
   bool relaxOnce(int pass) const override;
   bool synthesizeAlign(uint64_t &dot, InputSection *sec) override;
   RelExpr adjustTlsExpr(RelType type, RelExpr expr) const override;
-  void relocateAlloc(InputSectionBase &sec, uint8_t *buf) const override;
+  void relocateAlloc(InputSection &sec, uint8_t *buf) const override;
   void finalizeRelax(int passes) const override;
 
 private:
@@ -1395,13 +1395,9 @@ static bool pairForGotRels(ArrayRef<Relocation> relocs) {
   return i == size;
 }
 
-void LoongArch::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
+void LoongArch::relocateAlloc(InputSection &sec, uint8_t *buf) const {
   const unsigned bits = ctx.arg.is64 ? 64 : 32;
-  uint64_t secAddr = sec.getOutputSection()->addr;
-  if (auto *s = dyn_cast<InputSection>(&sec))
-    secAddr += s->outSecOff;
-  else if (auto *ehIn = dyn_cast<EhInputSection>(&sec))
-    secAddr += ehIn->getParent()->outSecOff;
+  uint64_t secAddr = sec.getOutputSection()->addr + sec.outSecOff;
   bool isExtreme = false, isRelax = false;
   const MutableArrayRef<Relocation> relocs = sec.relocs();
   const bool isPairForGotRels = pairForGotRels(relocs);
diff --git a/lld/ELF/Arch/PPC.cpp b/lld/ELF/Arch/PPC.cpp
@@ -49,7 +49,7 @@ class PPC final : public TargetInfo {
                 uint64_t val) const override;
   RelExpr adjustTlsExpr(RelType type, RelExpr expr) const override;
   int getTlsGdRelaxSkip(RelType type) const override;
-  void relocateAlloc(InputSectionBase &sec, uint8_t *buf) const override;
+  void relocateAlloc(InputSection &sec, uint8_t *buf) const override;
 
 private:
   void relaxTlsGdToIe(uint8_t *loc, const Relocation &rel, uint64_t val) const;
@@ -496,10 +496,8 @@ void PPC::relaxTlsIeToLe(uint8_t *loc, const Relocation &rel,
   }
 }
 
-void PPC::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
-  uint64_t secAddr = sec.getOutputSection()->addr;
-  if (auto *s = dyn_cast<InputSection>(&sec))
-    secAddr += s->outSecOff;
+void PPC::relocateAlloc(InputSection &sec, uint8_t *buf) const {
+  uint64_t secAddr = sec.getOutputSection()->addr + sec.outSecOff;
   for (const Relocation &rel : sec.relocs()) {
     uint8_t *loc = buf + rel.offset;
     const uint64_t val =
diff --git a/lld/ELF/Arch/PPC64.cpp b/lld/ELF/Arch/PPC64.cpp
@@ -190,7 +190,7 @@ class PPC64 final : public TargetInfo {
   RelExpr adjustGotPcExpr(RelType type, int64_t addend,
                           const uint8_t *loc) const override;
   void relaxGot(uint8_t *loc, const Relocation &rel, uint64_t val) const;
-  void relocateAlloc(InputSectionBase &sec, uint8_t *buf) const override;
+  void relocateAlloc(InputSection &sec, uint8_t *buf) const override;
 
   bool adjustPrologueForCrossSplitStack(uint8_t *loc, uint8_t *end,
                                         uint8_t stOther) const override;
@@ -1561,12 +1561,8 @@ void PPC64::relaxTlsGdToIe(uint8_t *loc, const Relocation &rel,
   }
 }
 
-void PPC64::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
-  uint64_t secAddr = sec.getOutputSection()->addr;
-  if (auto *s = dyn_cast<InputSection>(&sec))
-    secAddr += s->outSecOff;
-  else if (auto *ehIn = dyn_cast<EhInputSection>(&sec))
-    secAddr += ehIn->getParent()->outSecOff;
+void PPC64::relocateAlloc(InputSection &sec, uint8_t *buf) const {
+  uint64_t secAddr = sec.getOutputSection()->addr + sec.outSecOff;
   uint64_t lastPPCRelaxedRelocOff = -1;
   for (const Relocation &rel : sec.relocs()) {
     uint8_t *loc = buf + rel.offset;
diff --git a/lld/ELF/Arch/RISCV.cpp b/lld/ELF/Arch/RISCV.cpp
@@ -43,7 +43,7 @@ class RISCV final : public TargetInfo {
                      const uint8_t *loc) const override;
   void relocate(uint8_t *loc, const Relocation &rel,
                 uint64_t val) const override;
-  void relocateAlloc(InputSectionBase &sec, uint8_t *buf) const override;
+  void relocateAlloc(InputSection &sec, uint8_t *buf) const override;
   bool relaxOnce(int pass) const override;
   template <class ELFT, class RelTy>
   bool synthesizeAlignForInput(uint64_t &dot, InputSection *sec,
@@ -603,12 +603,8 @@ static void tlsdescToLe(uint8_t *loc, const Relocation &rel, uint64_t val) {
   }
 }
 
-void RISCV::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
-  uint64_t secAddr = sec.getOutputSection()->addr;
-  if (auto *s = dyn_cast<InputSection>(&sec))
-    secAddr += s->outSecOff;
-  else if (auto *ehIn = dyn_cast<EhInputSection>(&sec))
-    secAddr += ehIn->getParent()->outSecOff;
+void RISCV::relocateAlloc(InputSection &sec, uint8_t *buf) const {
+  uint64_t secAddr = sec.getOutputSection()->addr + sec.outSecOff;
   uint64_t tlsdescVal = 0;
   bool tlsdescRelax = false, isToLe = false;
   const ArrayRef<Relocation> relocs = sec.relocs();
diff --git a/lld/ELF/Arch/X86.cpp b/lld/ELF/Arch/X86.cpp
@@ -37,7 +37,7 @@ class X86 : public TargetInfo {
                 uint64_t val) const override;
 
   RelExpr adjustTlsExpr(RelType type, RelExpr expr) const override;
-  void relocateAlloc(InputSectionBase &sec, uint8_t *buf) const override;
+  void relocateAlloc(InputSection &sec, uint8_t *buf) const override;
 
 private:
   void relaxTlsGdToLe(uint8_t *loc, const Relocation &rel, uint64_t val) const;
@@ -491,10 +491,8 @@ void X86::relaxTlsLdToLe(uint8_t *loc, const Relocation &rel,
   memcpy(loc - 2, inst, sizeof(inst));
 }
 
-void X86::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
-  uint64_t secAddr = sec.getOutputSection()->addr;
-  if (auto *s = dyn_cast<InputSection>(&sec))
-    secAddr += s->outSecOff;
+void X86::relocateAlloc(InputSection &sec, uint8_t *buf) const {
+  uint64_t secAddr = sec.getOutputSection()->addr + sec.outSecOff;
   for (const Relocation &rel : sec.relocs()) {
     uint8_t *loc = buf + rel.offset;
     const uint64_t val =
diff --git a/lld/ELF/Arch/X86_64.cpp b/lld/ELF/Arch/X86_64.cpp
@@ -44,7 +44,7 @@ class X86_64 : public TargetInfo {
                          unsigned size) const override;
   RelExpr adjustGotPcExpr(RelType type, int64_t addend,
                           const uint8_t *loc) const override;
-  void relocateAlloc(InputSectionBase &sec, uint8_t *buf) const override;
+  void relocateAlloc(InputSection &sec, uint8_t *buf) const override;
   bool adjustPrologueForCrossSplitStack(uint8_t *loc, uint8_t *end,
                                         uint8_t stOther) const override;
   bool deleteFallThruJmpInsn(InputSection &is, InputFile *file,
@@ -1146,12 +1146,8 @@ bool X86_64::adjustPrologueForCrossSplitStack(uint8_t *loc, uint8_t *end,
   return false;
 }
 
-void X86_64::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
-  uint64_t secAddr = sec.getOutputSection()->addr;
-  if (auto *s = dyn_cast<InputSection>(&sec))
-    secAddr += s->outSecOff;
-  else if (auto *ehIn = dyn_cast<EhInputSection>(&sec))
-    secAddr += ehIn->getParent()->outSecOff;
+void X86_64::relocateAlloc(InputSection &sec, uint8_t *buf) const {
+  uint64_t secAddr = sec.getOutputSection()->addr + sec.outSecOff;
   for (const Relocation &rel : sec.relocs()) {
     if (rel.expr == R_NONE) // See deleteFallThruJmpInsn
       continue;
diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
@@ -1171,7 +1171,7 @@ void InputSection::relocateNonAlloc(Ctx &ctx, uint8_t *buf,
 }
 
 template <class ELFT>
-void InputSectionBase::relocate(Ctx &ctx, uint8_t *buf, uint8_t *bufEnd) {
+void InputSection::relocate(Ctx &ctx, uint8_t *buf, uint8_t *bufEnd) {
   if ((flags & SHF_EXECINSTR) && LLVM_UNLIKELY(getFile<ELFT>()->splitStack))
     adjustSplitStackFunctionPrologues<ELFT>(ctx, buf, bufEnd);
 
diff --git a/lld/ELF/InputSection.h b/lld/ELF/InputSection.h
@@ -262,10 +262,6 @@ class InputSectionBase : public SectionBase {
     return {*this, sym, offset};
   }
 
-  // Each section knows how to relocate itself. These functions apply
-  // relocations, assuming that Buf points to this section's copy in
-  // the mmap'ed output buffer.
-  template <class ELFT> void relocate(Ctx &, uint8_t *buf, uint8_t *bufEnd);
   uint64_t getRelocTargetVA(Ctx &, const Relocation &r, uint64_t p) const;
 
   // The native ELF reloc data type is not very convenient to handle.
@@ -443,8 +439,12 @@ class InputSection : public InputSectionBase {
 
   InputSectionBase *getRelocatedSection() const;
 
+  // Each section knows how to relocate itself. These functions apply
+  // relocations, assuming that `buf` points to this section's copy in
+  // the mmap'ed output buffer.
   template <class ELFT, class RelTy>
   void relocateNonAlloc(Ctx &, uint8_t *buf, Relocs<RelTy> rels);
+  template <class ELFT> void relocate(Ctx &, uint8_t *buf, uint8_t *bufEnd);
 
   // Points to the canonical section. If ICF folds two sections, repl pointer of
   // one section points to the other.
diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
@@ -1549,7 +1549,7 @@ void RelocationScanner::scanOne(typename Relocs<RelTy>::const_iterator &i) {
       sec->file->ppc64SmallCodeModelTocRelocs = true;
 
     // Record the TOC entry (.toc + addend) as not relaxable. See the comment in
-    // InputSectionBase::relocateAlloc().
+    // PPC64::relocateAlloc().
     if (type == R_PPC64_TOC16_LO && sym.isSection() && isa<Defined>(sym) &&
         cast<Defined>(sym).section->name == ".toc")
       ctx.ppc64noTocRelax.insert({&sym, addend});
diff --git a/lld/ELF/SyntheticSections.cpp b/lld/ELF/SyntheticSections.cpp
@@ -662,7 +662,7 @@ void EhFrameSection::writeTo(uint8_t *buf) {
   // in the output buffer, but relocateAlloc() still works because
   // getOffset() takes care of discontiguous section pieces.
   for (EhInputSection *s : sections)
-    ctx.target->relocateAlloc(*s, buf);
+    ctx.target->relocateEh(*s, buf);
 
   if (getPartition(ctx).ehFrameHdr && getPartition(ctx).ehFrameHdr->getParent())
     getPartition(ctx).ehFrameHdr->write();
diff --git a/lld/ELF/Target.cpp b/lld/ELF/Target.cpp
@@ -148,22 +148,30 @@ RelExpr TargetInfo::adjustGotPcExpr(RelType type, int64_t addend,
   return R_GOT_PC;
 }
 
-void TargetInfo::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
+static void relocateImpl(const TargetInfo &target, InputSectionBase &sec,
+                         uint64_t secAddr, uint8_t *buf) {
+  auto &ctx = target.ctx;
   const unsigned bits = ctx.arg.is64 ? 64 : 32;
-  uint64_t secAddr = sec.getOutputSection()->addr;
-  if (auto *s = dyn_cast<InputSection>(&sec))
-    secAddr += s->outSecOff;
-  else if (auto *ehIn = dyn_cast<EhInputSection>(&sec))
-    secAddr += ehIn->getParent()->outSecOff;
   for (const Relocation &rel : sec.relocs()) {
     uint8_t *loc = buf + rel.offset;
     const uint64_t val = SignExtend64(
         sec.getRelocTargetVA(ctx, rel, secAddr + rel.offset), bits);
     if (rel.expr != R_RELAX_HINT)
-      relocate(loc, rel, val);
+      target.relocate(loc, rel, val);
   }
 }
 
+void TargetInfo::relocateAlloc(InputSection &sec, uint8_t *buf) const {
+  uint64_t secAddr = sec.getOutputSection()->addr + sec.outSecOff;
+  relocateImpl(*this, sec, secAddr, buf);
+}
+
+// A variant of relocateAlloc that processes an EhInputSection.
+void TargetInfo::relocateEh(EhInputSection &sec, uint8_t *buf) const {
+  uint64_t secAddr = sec.getOutputSection()->addr + sec.getParent()->outSecOff;
+  relocateImpl(*this, sec, secAddr, buf);
+}
+
 uint64_t TargetInfo::getImageBase() const {
   // Use --image-base if set. Fall back to the target default if not.
   if (ctx.arg.imageBase)
diff --git a/lld/ELF/Target.h b/lld/ELF/Target.h
@@ -92,7 +92,8 @@ class TargetInfo {
   void relocateNoSym(uint8_t *loc, RelType type, uint64_t val) const {
     relocate(loc, Relocation{R_NONE, type, 0, 0, nullptr}, val);
   }
-  virtual void relocateAlloc(InputSectionBase &sec, uint8_t *buf) const;
+  virtual void relocateAlloc(InputSection &sec, uint8_t *buf) const;
+  void relocateEh(EhInputSection &sec, uint8_t *buf) const;
 
   // Do a linker relaxation pass and return true if we changed something.
   virtual bool relaxOnce(int pass) const { return false; }

Original file line number	Diff line number	Diff line change
`@@ -1171,7 +1171,7 @@ void InputSection::relocateNonAlloc(Ctx &ctx, uint8_t *buf,`
`1171`	`1171`	`}`
`1172`	`1172`
`1173`	`1173`	`template <class ELFT>`
`1174`		`-void InputSectionBase::relocate(Ctx &ctx, uint8_t buf, uint8_t bufEnd) {`
	`1174`	`+void InputSection::relocate(Ctx &ctx, uint8_t buf, uint8_t bufEnd) {`
`1175`	`1175`	`if ((flags & SHF_EXECINSTR) && LLVM_UNLIKELY(getFile<ELFT>()->splitStack))`
`1176`	`1176`	`adjustSplitStackFunctionPrologues<ELFT>(ctx, buf, bufEnd);`
`1177`	`1177`