llvm · pcc · Mar 28, 2025 · Apr 10, 2025 · Apr 10, 2025 · Apr 10, 2025
diff --git a/lld/ELF/Arch/AArch64.cpp b/lld/ELF/Arch/AArch64.cpp
@@ -113,6 +113,7 @@ AArch64::AArch64(Ctx &ctx) : TargetInfo(ctx) {
   copyRel = R_AARCH64_COPY;
   relativeRel = R_AARCH64_RELATIVE;
   iRelativeRel = R_AARCH64_IRELATIVE;
+  iRelSymbolicRel = R_AARCH64_FUNCINIT64;
   gotRel = R_AARCH64_GLOB_DAT;
   pltRel = R_AARCH64_JUMP_SLOT;
   symbolicRel = R_AARCH64_ABS64;
@@ -136,6 +137,7 @@ RelExpr AArch64::getRelExpr(RelType type, const Symbol &s,
   case R_AARCH64_ABS16:
   case R_AARCH64_ABS32:
   case R_AARCH64_ABS64:
+  case R_AARCH64_FUNCINIT64:
   case R_AARCH64_ADD_ABS_LO12_NC:
   case R_AARCH64_LDST128_ABS_LO12_NC:
   case R_AARCH64_LDST16_ABS_LO12_NC:
@@ -260,7 +262,8 @@ bool AArch64::usesOnlyLowPageBits(RelType type) const {
 }
 
 RelType AArch64::getDynRel(RelType type) const {
-  if (type == R_AARCH64_ABS64 || type == R_AARCH64_AUTH_ABS64)
+  if (type == R_AARCH64_ABS64 || type == R_AARCH64_AUTH_ABS64 ||
+      type == R_AARCH64_FUNCINIT64)
     return type;
   return R_AARCH64_NONE;
 }

diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
@@ -992,8 +992,9 @@ bool RelocationScanner::isStaticLinkTimeConstant(RelExpr e, RelType type,
   if (e == R_GOT || e == R_PLT)
     return ctx.target->usesOnlyLowPageBits(type) || !ctx.arg.isPic;
 
-  // R_AARCH64_AUTH_ABS64 requires a dynamic relocation.
-  if (sym.isPreemptible || e == RE_AARCH64_AUTH)
+  // R_AARCH64_AUTH_ABS64 and iRelSymbolicRel require a dynamic relocation.
+  if (sym.isPreemptible || e == RE_AARCH64_AUTH ||
+      type == ctx.target->iRelSymbolicRel)
     return false;
   if (!ctx.arg.isPic)
     return true;
@@ -1171,6 +1172,24 @@ void RelocationScanner::processAux(RelExpr expr, RelType type, uint64_t offset,
         }
         return;
       }
+      if (LLVM_UNLIKELY(type == ctx.target->iRelSymbolicRel)) {
+        if (sym.isPreemptible) {
+          auto diag = Err(ctx);
+          diag << "relocation " << type
+               << " cannot be used against preemptible symbol '" << &sym << "'";
+          printLocation(diag, *sec, sym, offset);
+        } else if (isIfunc) {
+          auto diag = Err(ctx);
+          diag << "relocation " << type
+               << " cannot be used against ifunc symbol '" << &sym << "'";
+          printLocation(diag, *sec, sym, offset);
+        } else {
+          part.relaDyn->addReloc({ctx.target->iRelativeRel, sec, offset,
+                                  DynamicReloc::AddendOnlyWithTargetVA, sym,
+                                  addend, R_ABS});
+          return;
+        }
+      }
       part.relaDyn->addSymbolReloc(rel, *sec, offset, sym, addend, type);
 
       // MIPS ABI turns using of GOT and dynamic relocations inside out.

diff --git a/lld/ELF/Target.h b/lld/ELF/Target.h
@@ -130,6 +130,7 @@ class TargetInfo {
   RelType relativeRel = 0;
   RelType iRelativeRel = 0;
   RelType symbolicRel = 0;
+  RelType iRelSymbolicRel = 0;
   RelType tlsDescRel = 0;
   RelType tlsGotRel = 0;
   RelType tlsModuleIndexRel = 0;

diff --git a/lld/test/ELF/aarch64-funcinit64-invalid.s b/lld/test/ELF/aarch64-funcinit64-invalid.s
@@ -0,0 +1,18 @@
+# REQUIRES: aarch64
+
+# RUN: llvm-mc -filetype=obj -triple=aarch64 %s -o %t.o
+# RUN: not ld.lld %t.o -o %t 2>&1 | FileCheck --check-prefix=ERR %s
+
+.rodata
+# ERR: relocation R_AARCH64_FUNCINIT64 cannot be used against symbol 'func'
+.8byte func@FUNCINIT
+
+.data
+# ERR: relocation R_AARCH64_FUNCINIT64 cannot be used against ifunc symbol 'ifunc'
+.8byte ifunc@FUNCINIT
+
+.text
+func:
+.type ifunc, @gnu_indirect_function
+ifunc:
+ret
diff --git a/lld/test/ELF/aarch64-funcinit64.s b/lld/test/ELF/aarch64-funcinit64.s
@@ -0,0 +1,19 @@
+# REQUIRES: aarch64
+
+# RUN: llvm-mc -filetype=obj -triple=aarch64 %s -o %t.o
+# RUN: ld.lld %t.o -o %t
+# RUN: llvm-readelf -s -r %t | FileCheck %s
+# RUN: ld.lld %t.o -o %t -pie
+# RUN: llvm-readelf -s -r %t | FileCheck %s
+# RUN: not ld.lld %t.o -o %t -shared 2>&1 | FileCheck --check-prefix=ERR %s
+
+.data
+# CHECK: R_AARCH64_IRELATIVE [[FOO:[0-9a-f]*]]
+# ERR: relocation R_AARCH64_FUNCINIT64 cannot be used against preemptible symbol 'foo'
+.8byte foo@FUNCINIT
+
+.text
+# CHECK: {{0*}}[[FOO]] {{.*}} foo
+.globl foo
+foo:
+ret
diff --git a/llvm/include/llvm/BinaryFormat/ELFRelocs/AArch64.def b/llvm/include/llvm/BinaryFormat/ELFRelocs/AArch64.def
@@ -140,6 +140,7 @@ ELF_RELOC(R_AARCH64_TLS_DTPREL64,                    0x405)
 ELF_RELOC(R_AARCH64_TLS_TPREL64,                     0x406)
 ELF_RELOC(R_AARCH64_TLSDESC,                         0x407)
 ELF_RELOC(R_AARCH64_IRELATIVE,                       0x408)
+ELF_RELOC(R_AARCH64_FUNCINIT64,                      0x409)
 // PAuthABI static and dynamic relocations: defined in pauthabielf64,
 // https://github.com/ARM-software/abi-aa
 ELF_RELOC(R_AARCH64_AUTH_ABS64,                      0x244)

diff --git a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -8203,6 +8203,8 @@ bool AArch64AsmParser::parseDataExpr(const MCExpr *&Res) {
       Spec = AArch64MCExpr::VK_GOTPCREL;
     else if (Identifier == "plt")
       Spec = AArch64MCExpr::VK_PLT;
+    else if (Identifier == "funcinit")
+      Spec = AArch64MCExpr::VK_FUNCINIT;
   }
   if (Spec == AArch64MCExpr::None)
     return Error(Loc, "invalid relocation specifier");

diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64ELFObjectWriter.cpp
@@ -237,6 +237,8 @@ unsigned AArch64ELFObjectWriter::getRelocType(MCContext &Ctx,
       if (RefKind == AArch64MCExpr::VK_AUTH ||
           RefKind == AArch64MCExpr::VK_AUTHADDR)
         return ELF::R_AARCH64_AUTH_ABS64;
+      if (RefKind == AArch64MCExpr::VK_FUNCINIT)
+        return ELF::R_AARCH64_FUNCINIT64;
       return ELF::R_AARCH64_ABS64;
     }
     case AArch64::fixup_aarch64_add_imm12:

diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCAsmInfo.cpp
@@ -41,6 +41,7 @@ const MCAsmInfo::AtSpecifier ELFAtSpecifiers[] = {
     {AArch64MCExpr::VK_GOT, "GOT"},
     {AArch64MCExpr::VK_GOTPCREL, "GOTPCREL"},
     {AArch64MCExpr::VK_PLT, "PLT"},
+    {AArch64MCExpr::VK_FUNCINIT, "FUNCINIT"},
 };
 
 const MCAsmInfo::AtSpecifier MachOAtSpecifiers[] = {

diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.h b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCExpr.h
@@ -42,6 +42,7 @@ class AArch64MCExpr : public MCTargetExpr {
     VK_AUTHADDR     = 0x00b,
     VK_GOT_AUTH     = 0x00c,
     VK_TLSDESC_AUTH = 0x00d,
+    VK_FUNCINIT     = 0x00e,
     VK_SymLocBits   = 0x00f,
 
     // Variants specifying which part of the final address calculation is

diff --git a/llvm/test/MC/AArch64/data-directive-specifier.s b/llvm/test/MC/AArch64/data-directive-specifier.s
@@ -12,6 +12,7 @@ l:
 # CHECK-NEXT:   0x8 R_AARCH64_PLT32 extern 0x4
 # CHECK-NEXT:   0xC R_AARCH64_PLT32 g 0x8
 # CHECK-NEXT:   0x10 R_AARCH64_PLT32 g 0x18
+# CHECK-NEXT:   0x14 R_AARCH64_FUNCINIT64 l 0x0
 # CHECK-NEXT: }
 .data
 .word l@plt - .
@@ -21,6 +22,8 @@ l:
 .word g@plt - . + 8
 .word g@plt - .data + 8
 
+.quad l@funcinit
+
 # CHECK:      Section ({{.*}}) .rela.data1 {
 # CHECK-NEXT:   0x0 R_AARCH64_GOTPCREL32 data1 0x0
 # CHECK-NEXT:   0x4 R_AARCH64_GOTPCREL32 extern 0x4