Index: ELF/MarkLive.cpp =================================================================== --- ELF/MarkLive.cpp +++ ELF/MarkLive.cpp @@ -267,10 +267,16 @@ // input sections. This function make some or all of them on // so that they are emitted to the output file. template void elf::markLive() { - // If -gc-sections is missing, no sections are removed. if (!Config->GcSections) { + // If -gc-sections is missing, no sections are removed. for (InputSectionBase *Sec : InputSections) Sec->Live = true; + + // If a DSO defines a symbol referenced in a regular object, it is needed. + for (Symbol *Sym : Symtab->getSymbols()) + if (auto *S = dyn_cast(Sym)) + if (S->IsUsedInRegularObj && !S->isWeak()) + S->getFile().IsNeeded = true; return; } Index: ELF/SymbolTable.cpp =================================================================== --- ELF/SymbolTable.cpp +++ ELF/SymbolTable.cpp @@ -503,14 +503,11 @@ if ((S->isUndefined() || S->isLazy()) && S->Visibility == STV_DEFAULT) { uint8_t Binding = S->Binding; - bool WasUndefined = S->isUndefined(); replaceSymbol(S, File, Name, Sym.getBinding(), Sym.st_other, Sym.getType(), Sym.st_value, Sym.st_size, Alignment, VerdefIndex); S->Binding = Binding; - if (!S->isWeak() && !Config->GcSections && WasUndefined) - File.IsNeeded = true; } } Index: test/ELF/as-needed-in-regular.s =================================================================== --- test/ELF/as-needed-in-regular.s +++ test/ELF/as-needed-in-regular.s @@ -0,0 +1,24 @@ +# REQUIRES: x86 + +# RUN: echo '.globl a; .type a, @function; .type a, @function; a: ret' | \ +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux - -o %ta.o +# RUN: ld.lld %ta.o --shared --soname=a.so -o %ta.so + +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o +# RUN: ld.lld %t.o --as-needed %ta.so -o %t +# RUN: llvm-readelf -d %t | FileCheck %s +# RUN: ld.lld %t.o --as-needed %ta.so --gc-sections -o %t +# RUN: llvm-readelf -d %t | FileCheck %s + +# The order of %ta.so and %t.o does not matter. + +# RUN: ld.lld --as-needed %ta.so %t.o -o %t +# RUN: llvm-readelf -d %t | FileCheck %s +# RUN: ld.lld --as-needed %ta.so %t.o --gc-sections -o %t +# RUN: llvm-readelf -d %t | FileCheck %s + +# CHECK: a.so + +.global _start +_start: + jmp a@PLT Index: test/ELF/as-needed-not-in-regular.s =================================================================== --- test/ELF/as-needed-not-in-regular.s +++ test/ELF/as-needed-not-in-regular.s @@ -0,0 +1,26 @@ +# REQUIRES: x86 + +# RUN: echo '.globl a1, a2; .type a1, @function; .type a2, @function; a1: a2: ret' | \ +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux - -o %ta.o +# RUN: ld.lld %ta.o --shared --soname=a.so -o %ta.so + +# RUN: echo '.globl b; .type b, @function; b: jmp a1@PLT' | \ +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux - -o %tb.o +# RUN: ld.lld %tb.o %ta.so --shared --soname=b.so -o %tb.so + +# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o +# RUN: ld.lld %t.o %tb.so --as-needed %ta.so -o %t +# RUN: llvm-readelf -d %t | FileCheck %s + +# RUN: ld.lld %t.o %tb.so --as-needed %ta.so --gc-sections -o %t +# RUN: llvm-readelf -d %t | FileCheck %s + +# The symbol a1 (defined in a.so) is not referenced by a regular object, +# the reference to a2 is weak, don't add a DT_NEEDED entry for a.so. +# CHECK-NOT: a.so + +.global _start +.weak a2 +_start: + jmp b@PLT + jmp a2