diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -639,6 +639,8 @@
 
     // .ARM.exidx sections have a reverse dependency on the InputSection they
     // have a SHF_LINK_ORDER dependency, this is identified by the sh_link.
+    if (!sec.sh_link)
+      continue;
     InputSectionBase *linkSec = nullptr;
     if (sec.sh_link < this->sections.size())
       linkSec = this->sections[sec.sh_link];
diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -274,8 +274,9 @@
 }
 
 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
@@ -1500,6 +1500,8 @@
 static bool compareByFilePosition(InputSection *a, InputSection *b) {
   InputSection *la = a->getLinkOrderDep();
   InputSection *lb = b->getLinkOrderDep();
+  if (!la || !lb)
+    return !la && lb;
   OutputSection *aOut = la->getParent();
   OutputSection *bOut = lb->getParent();
 
@@ -1530,7 +1532,7 @@
           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-link.test b/lld/test/ELF/linkorder-mixed-link.test
new file mode 100644
--- /dev/null
+++ b/lld/test/ELF/linkorder-mixed-link.test
@@ -0,0 +1,33 @@
+## Test that we allow SHF_LINK_ORDER sections with sh_link=0.
+# RUN: yaml2obj %s -o %t.o
+# RUN: ld.lld %t.o -o %t
+# RUN: llvm-readelf -S %t | FileCheck %s
+
+# CHECK: Name       {{.*}} Flg Lk Inf
+# CHECK: .linkorder {{.*}}  AL  0   0
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_REL
+  Machine: EM_X86_64
+Sections:
+  - Name: .text [0]
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+  - Name: .text [1]
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+  - Name:  .linkorder [0]
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_ALLOC, SHF_LINK_ORDER ]
+    Link:  0
+  - Name:  .linkorder [1]
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_ALLOC, SHF_LINK_ORDER ]
+    Link:  1
+  - Name:  .linkorder [2]
+    Type:  SHT_PROGBITS
+    Flags: [ SHF_ALLOC, SHF_LINK_ORDER ]
+    Link:  2