Index: ELF/Writer.cpp =================================================================== --- ELF/Writer.cpp +++ ELF/Writer.cpp @@ -907,6 +907,11 @@ if (!InX::DynSymTab) Symtab::X->addIgnored("__tls_get_addr"); + // __dso_handle symbol is passed to cxa_finalize as a marker to identify + // each DSO. The address of the symbol doesn't matter as long as they are + // different in different DSOs, so we chose the start address of the DSO. + addOptionalRegular("__dso_handle", Out::ElfHeader, 0, STV_HIDDEN); + // __ehdr_start is the location of ELF file headers. Note that we define // this symbol unconditionally even when using a linker script, which // differs from the behavior implemented by GNU linker which only define Index: test/ELF/dso_handle.s =================================================================== --- /dev/null +++ test/ELF/dso_handle.s @@ -0,0 +1,19 @@ +# REQUIRES: x86 + +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o +# RUN: ld.lld -shared %t.o -o %t +# RUN: llvm-readobj -symbols %t | FileCheck %s +# CHECK: Name: __dso_handle +# CHECK-NEXT: Value: 0x0 +# CHECK-NEXT: Size: 0 +# CHECK-NEXT: Binding: Local +# CHECK-NEXT: Type: None +# CHECK-NEXT: Other [ +# CHECK-NEXT: STV_HIDDEN +# CHECK-NEXT: ] +# CHECK-NEXT: Section: .dynsym + +.text +.global foo, __dso_handle +foo: + lea __dso_handle(%rip),%rax