diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -657,17 +657,19 @@
     if (sec.sh_type == SHT_REL || sec.sh_type == SHT_RELA)
       this->sections[i] = createInputSection(sec);
 
-    if (!(sec.sh_flags & SHF_LINK_ORDER))
+    // A SHF_LINK_ORDER section with sh_link=0 is handled as if it did not have
+    // the flag.
+    if (!(sec.sh_flags & SHF_LINK_ORDER) || !sec.sh_link)
       continue;
 
-    // .ARM.exidx sections have a reverse dependency on the InputSection they
-    // have a SHF_LINK_ORDER dependency, this is identified by the sh_link.
     InputSectionBase *linkSec = nullptr;
     if (sec.sh_link < this->sections.size())
       linkSec = this->sections[sec.sh_link];
     if (!linkSec)
       fatal(toString(this) + ": invalid sh_link index: " + Twine(sec.sh_link));
 
+    // A SHF_LINK_ORDER section is discarded if its linked-to section is
+    // discarded.
     InputSection *isec = cast<InputSection>(this->sections[i]);
     linkSec->dependentSections.push_back(isec);
     if (!isa<InputSection>(linkSec))
diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -276,8 +276,9 @@
 }
 
 InputSection *InputSectionBase::getLinkOrderDep() const {
-  assert(link);
   assert(flags & SHF_LINK_ORDER);
+  if (!link)
+    return nullptr;
   return cast<InputSection>(file->getSections()[link]);
 }
 
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -1606,6 +1606,9 @@
 static bool compareByFilePosition(InputSection *a, InputSection *b) {
   InputSection *la = a->getLinkOrderDep();
   InputSection *lb = b->getLinkOrderDep();
+  // SHF_LINK_ORDER sections with non-zero sh_link are ordered before others.
+  if (!la || !lb)
+    return la && !lb;
   OutputSection *aOut = la->getParent();
   OutputSection *bOut = lb->getParent();
 
@@ -1646,7 +1649,7 @@
             sections.push_back(isec);
 
             InputSection *link = isec->getLinkOrderDep();
-            if (!link->getParent())
+            if (link && !link->getParent())
               error(toString(isec) + ": sh_link points to discarded section " +
                     toString(link));
           }
diff --git a/lld/test/ELF/invalid/linkorder-invalid-sec2.test b/lld/test/ELF/invalid/linkorder-invalid-sec2.test
deleted file mode 100644
--- a/lld/test/ELF/invalid/linkorder-invalid-sec2.test
+++ /dev/null
@@ -1,16 +0,0 @@
-# REQUIRES: x86
-# RUN: yaml2obj %s -o %t.o
-# RUN: not ld.lld %t.o -o /dev/null 2>&1 | FileCheck %s
-# CHECK: invalid sh_link index: 0
-
---- !ELF
-FileHeader:
-  Class:           ELFCLASS64
-  Data:            ELFDATA2LSB
-  Type:            ET_REL
-  Machine:         EM_X86_64
-Sections:
-  - Name:          .linkorder
-    Type:          SHT_PROGBITS
-    Flags:         [ SHF_ALLOC, SHF_EXECINSTR, SHF_LINK_ORDER ]
-    Link:          0
diff --git a/lld/test/ELF/linkorder-mixed.s b/lld/test/ELF/linkorder-mixed.s
new file mode 100644
--- /dev/null
+++ b/lld/test/ELF/linkorder-mixed.s
@@ -0,0 +1,39 @@
+## Test that we allow SHF_LINK_ORDER sections with sh_link=0.
+## SHF_LINK_ORDER sections with sh_link!=0 are ordered before others.
+# RUN: llvm-mc -filetype=obj %s -o %t.o
+# RUN: ld.lld %t.o -o %t
+# RUN: llvm-readelf -S -x .linkorder %t | FileCheck %s
+
+# CHECK:      [Nr] Name       {{.*}} Size   ES Flg Lk Inf
+# CHECK-NEXT: [ 0]            {{.*}}
+# CHECK-NEXT: [ 1] .linkorder {{.*}} 000004 00  AL  3   0
+# CHECK-NEXT: [ 2] .ignore    {{.*}}
+# CHECK-NEXT: [ 3] .text      {{.*}}
+
+# CHECK:      Hex dump of section '.linkorder':
+# CHECK-NEXT:   [[#%x,ADDR:]] 01020003
+
+## TODO Allow non-contiguous SHF_LINK_ORDER sections in an output section.
+# RUN: llvm-mc --filetype=obj --defsym EXTRA=1 %s -o %t.o
+# RUN: not ld.lld %t.o -o /dev/null
+
+.section .text,"ax",@progbits,unique,0
+.Ltext0:
+.section .text,"ax",@progbits,unique,1
+.Ltext1:
+.section .linkorder,"ao",@progbits,0,unique,0
+  .byte 0
+.section .linkorder,"ao",@progbits,.Ltext0
+  .byte 1
+.section .linkorder,"ao",@progbits,.Ltext1
+  .byte 2
+
+.ifdef EXTRA
+.section .linkorder,"a",@progbits
+  .byte 4
+.else
+.section .ignore,"ao",@progbits,.Ltext1
+.endif
+
+.section .linkorder,"ao",@progbits,0,unique,3
+  .byte 3