ELF: Treat IFunc definitions in DSOs as functions.

[• rafael]

Interesting. I assume the dynamic linker then does all the work of
calling the resolver function and setting the got entry.

• /dev/null

+++ test/ELF/Inputs/gnu-ifunc-gotpcrel.s
@@ -0,0 +1,5 @@
+.type foo STT_GNU_IFUNC
+.globl foo
+.type foo, @function

Why do you need two .type directives?

LGTM with that changed.

Cheers,
Rafael

[ruiu]

LGTM

ELF/Symbols.h

 public:
   static bool classof(const SymbolBody *S) {
     return S->kind() == SymbolBody::SharedKind;
   }
 
   SharedSymbol(SharedFile<ELFT> *F, StringRef Name, const Elf_Sym &Sym)
       : Defined(SymbolBody::SharedKind, Name, Sym.getBinding(), Sym.st_other,
                 Sym.getType()),
-        File(F), Sym(Sym) {}
+        File(F), Sym(Sym) {
+    // IFuncs defined in DSOs are treated as functions by the static linker.
+    if (isGnuIFunc())
+      Type = llvm::ELF::STT_FUNC;
+  }
 
   SharedFile<ELFT> *File;
   const Elf_Sym &Sym;
 
   // OffsetInBss is significant only when needsCopy() is true.
   uintX_t OffsetInBss = 0;
 
   bool needsCopy() const { return this->NeedsCopyOrPltAddr && !this->isFunc(); }

test/ELF/Inputs/gnu-ifunc-gotpcrel.s

+.type foo STT_GNU_IFUNC
+.globl foo
+.type foo, @function
+foo:
+ret

test/ELF/gnu-ifunc-gotpcrel.s

+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %S/Inputs/gnu-ifunc-gotpcrel.s -o %t2.o
+# RUN: ld.lld -shared %t2.o -o %t2.so
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: ld.lld %t.o %t2.so -o %t
+# RUN: llvm-readobj -dyn-relocations %t | FileCheck %s
+
+# CHECK:      Dynamic Relocations {
+# CHECK-NEXT:   0x120B0 R_X86_64_GLOB_DAT foo 0x0
+# CHECK-NEXT: }
+
+.globl _start
+_start:
+mov foo@gotpcrel(%rip), %rax