diff -r -u --new-file lld-7.0.1.src.orig/ELF/InputFiles.cpp lld-7.0.1.src/ELF/InputFiles.cpp

--- lld-7.0.1.src.orig/ELF/InputFiles.cpp	2019-01-25 10:12:56.412850573 +0000

+++ lld-7.0.1.src/ELF/InputFiles.cpp	2019-01-25 10:14:50.557726268 +0000

@@ -324,17 +324,6 @@

   return Signature;

 }

-template <class ELFT>

-ArrayRef<typename ObjFile<ELFT>::Elf_Word>

-ObjFile<ELFT>::getShtGroupEntries(const Elf_Shdr &Sec) {

-  const ELFFile<ELFT> &Obj = this->getObj();

-  ArrayRef<Elf_Word> Entries =

-      CHECK(Obj.template getSectionContentsAsArray<Elf_Word>(&Sec), this);

-  if (Entries.empty() || Entries[0] != GRP_COMDAT)

-    fatal(toString(this) + ": unsupported SHT_GROUP format");

-  return Entries.slice(1);

-}

-

 template <class ELFT> bool ObjFile<ELFT>::shouldMerge(const Elf_Shdr &Sec) {

   // On a regular link we don't merge sections if -O0 (default is -O1). This

   // sometimes makes the linker significantly faster, although the output will

@@ -439,22 +428,33 @@

     case SHT_GROUP: {

       // De-duplicate section groups by their signatures.

       StringRef Signature = getShtGroupSignature(ObjSections, Sec);

-      bool IsNew = ComdatGroups.insert(CachedHashStringRef(Signature)).second;

       this->Sections[I] = &InputSection::Discarded;

-      // If it is a new section group, we want to keep group members.

-      // Group leader sections, which contain indices of group members, are

-      // discarded because they are useless beyond this point. The only

-      // exception is the -r option because in order to produce re-linkable

-      // object files, we want to pass through basically everything.

+      ArrayRef<Elf_Word> Entries =

+          CHECK(Obj.template getSectionContentsAsArray<Elf_Word>(&Sec), this);

+      if (Entries.empty())

+        fatal(toString(this) + ": empty SHT_GROUP");

+

+      // The first word of a SHT_GROUP section contains flags. Currently,

+      // the standard defines only "GRP_COMDAT" flag for the COMDAT group.

+      // An group with the empty flag doesn't define anything; such sections

+      // are just skipped.

+      if (Entries[0] == 0)

+        continue;

+

+      if (Entries[0] != GRP_COMDAT)

+        fatal(toString(this) + ": unsupported SHT_GROUP format");

+

+      bool IsNew = ComdatGroups.insert(CachedHashStringRef(Signature)).second;

       if (IsNew) {

         if (Config->Relocatable)

           this->Sections[I] = createInputSection(Sec);

         continue;

       }

+

       // Otherwise, discard group members.

-      for (uint32_t SecIndex : getShtGroupEntries(Sec)) {

+      for (uint32_t SecIndex : Entries.slice(1)) {

         if (SecIndex >= Size)

           fatal(toString(this) +

                 ": invalid section index in group: " + Twine(SecIndex));

diff -r -u --new-file lld-7.0.1.src.orig/test/ELF/sht-group-empty.test lld-7.0.1.src/test/ELF/sht-group-empty.test

--- lld-7.0.1.src.orig/test/ELF/sht-group-empty.test	1970-01-01 00:00:00.000000000 +0000

+++ lld-7.0.1.src/test/ELF/sht-group-empty.test	2019-01-25 10:13:19.312026250 +0000

@@ -0,0 +1,55 @@

+# RUN: yaml2obj %s -o %t.o

+# RUN: ld.lld %t.o %t.o -o %t -r

+# RUN: llvm-readobj -s %t | FileCheck %s

+

+# CHECK:     Name: .text.foo

+# CHECK:     Name: .rela.text.foo

+

+--- !ELF

+FileHeader:

+  Class:           ELFCLASS64

+  Data:            ELFDATA2LSB

+  Type:            ET_REL

+  Machine:         EM_X86_64

+Sections:

+  - Name:            .group

+    Type:            SHT_GROUP

+    Link:            .symtab

+    Info:            foo

+    Members:

+      - SectionOrType:    GRP_COMDAT

+      - SectionOrType:    .text.foo

+      - SectionOrType:    .text.bar

+      - SectionOrType:    .note

+  - Name:            .note

+    Type:            SHT_NOTE

+    Flags:           [ SHF_GROUP ]

+  - Name:            .text.foo

+    Type:            SHT_PROGBITS

+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR, SHF_GROUP ]

+  - Name:            .text.bar

+    Type:            SHT_PROGBITS

+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR, SHF_GROUP ]

+  - Name:            .rela.text.foo

+    Type:            SHT_RELA

+    Flags:           [ SHF_INFO_LINK, SHF_GROUP ]

+    Link:            .symtab

+    Info:            .text.foo

+    Relocations:

+      - Offset:          0x0000000000000000

+        Symbol:          foo

+        Type:            R_X86_64_64

+  - Name:            .rela.text.bar

+    Type:            SHT_RELA

+    Flags:           [ SHF_INFO_LINK, SHF_GROUP ]

+    Link:            .symtab

+    Info:            .text.bar

+    Relocations:

+      - Offset:          0x0000000000000000

+        Symbol:          bar

+        Type:            R_X86_64_64

+Symbols:

+  Global:

+    - Name:            foo

+    - Name:            bar

+