Index: llvm/test/tools/llvm-objcopy/ELF/rename-section-relocsec.test
===================================================================
--- /dev/null
+++ llvm/test/tools/llvm-objcopy/ELF/rename-section-relocsec.test
@@ -0,0 +1,110 @@
+# RUN: yaml2obj %s -o %t
+
+## When a section is renamed, its relocation section should be renamed similarly.
+# RUN: llvm-objcopy %t - --rename-section=.text=.foo --rename-section=.data=.bar | \
+# RUN:   llvm-readobj --sections - | \
+# RUN:   FileCheck %s --check-prefix=TEST1
+# TEST1: Name: .foo
+# TEST1: Name: .rel.foo
+# TEST1: Name: .rela.bar
+# TEST1: Name: .bar
+
+## A relocation section should be renamed when its target section is renamed
+## even if its name does not follow the typical pattern.
+## Note that in the input file, '.rel.fn' targets '.sub', not '.fn'.
+# RUN: llvm-objcopy %t - --rename-section=.sub=.func | \
+# RUN:   llvm-readobj --sections - | \
+# RUN:   FileCheck %s --check-prefix=TEST2
+# TEST2: Name: .fn
+# TEST2: Name: .func
+# TEST2: Name: .rel.func
+
+## A relocation section should not be renamed if an unrelated section with
+## the same common name is related.
+## Note that in the input file, 'rel.fn' does not target 'fn'.
+# RUN: llvm-objcopy %t - --rename-section=.fn=.foo | \
+# RUN:   llvm-readobj --sections - | \
+# RUN:   FileCheck %s --check-prefix=TEST3
+# TEST3: Name: .foo
+# TEST3: Name: .sub
+# TEST3: Name: .rel.fn
+
+## A relocation section can be renamed with an explicit --rename-section command.
+# RUN: llvm-objcopy %t - --rename-section=.rel.text=.rel.foo --rename-section=.rela.data=.rela.bar | \
+# RUN:   llvm-readobj --sections - | \
+# RUN:   FileCheck %s --check-prefix=TEST4
+# TEST4: Name: .text
+# TEST4: Name: .rel.foo
+# TEST4: Name: .rela.bar
+# TEST4: Name: .data
+
+## Explicit renaming is preferred.
+# RUN: llvm-objcopy %t - --rename-section=.text=.foo --rename-section=.data=.bar --rename-section=.sub=.func \
+# RUN:     --rename-section=.rel.text=.rel.baz --rename-section=.rela.data=.rela.qux --rename-section=.rel.fn=.funcrelocs | \
+# RUN:   llvm-readobj --sections - | \
+# RUN:   FileCheck %s --check-prefix=TEST5
+# TEST5: Name: .foo
+# TEST5: Name: .rel.baz
+# TEST5: Name: .rela.qux
+# TEST5: Name: .bar
+# TEST5: Name: .fn
+# TEST5: Name: .func
+# TEST5: Name: .funcrelocs
+
+## Should not rename a relocation section if it or its target are not specified in --rename-section.
+## Note that this diverges from GNU objcopy.
+# RUN: llvm-objcopy %t - --rename-section=.text=.foo | \
+# RUN:   llvm-readobj --sections - | \
+# RUN:   FileCheck %s --check-prefix=TEST6
+# TEST6: Name: .fn
+# TEST6: Name: .sub
+# TEST6: Name: .rel.fn
+
+## A dynamic relocation section should not be renamed together with its target section
+# RUN: llvm-objcopy %t - --rename-section=.got.plt=.foo | \
+# RUN:   llvm-readobj --sections - | \
+# RUN:   FileCheck %s --check-prefix=TEST7
+# TEST7: Name: .rela.plt
+# TEST7: Name: .foo
+
+## A dynamic relocation section can be renamed with an explicit --rename-section command.
+# RUN: llvm-objcopy %t - --rename-section=.rela.plt=.rela.baz | \
+# RUN:   llvm-readobj --sections - | \
+# RUN:   FileCheck %s --check-prefix=TEST8
+# TEST8: Name: .rela.baz
+# TEST8: Name: .got.plt
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+  - Name:            .rel.text
+    Type:            SHT_REL
+    Info:            .text
+  - Name:            .rela.data
+    Type:            SHT_RELA
+    Info:            .data
+  - Name:            .data
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+  - Name:            .fn
+    Type:            SHT_PROGBITS
+  - Name:            .sub
+    Type:            SHT_PROGBITS
+  - Name:            .rel.fn
+    Type:            SHT_REL
+## Note: '.rel.fn' targets '.sub', not '.fn'
+    Info:            .sub
+  - Name:            .rela.plt
+    Type:            SHT_RELA
+    Flags:           [ SHF_ALLOC ]
+    Info:            .got.plt
+  - Name:            .got.plt
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_WRITE ]
Index: llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
===================================================================
--- llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
+++ llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
@@ -588,14 +588,31 @@
     return E;
 
   if (!Config.SectionsToRename.empty()) {
+    std::vector<RelocationSectionBase *> RelocSections;
+    DenseSet<SectionBase *> RenamedSections;
     for (SectionBase &Sec : Obj.sections()) {
+      auto *RelocSec = dyn_cast<RelocationSectionBase>(&Sec);
       const auto Iter = Config.SectionsToRename.find(Sec.Name);
       if (Iter != Config.SectionsToRename.end()) {
         const SectionRename &SR = Iter->second;
         Sec.Name = std::string(SR.NewName);
         if (SR.NewFlags.hasValue())
           setSectionFlagsAndType(Sec, SR.NewFlags.getValue());
-      }
+        RenamedSections.insert(&Sec);
+      } else if (RelocSec && !(Sec.Flags & SHF_ALLOC))
+        // Postpone processing relocation sections which are not specified in
+        // their explicit '--rename-section' commands untile after their target
+        // sections are renamed,
+        // Dynamic relocation sections (i.e. ones with SHF_ALLOC) should be
+        // renamed only explicitly. Otherwise, renaming, for example, 'got.plt'
+        // would affect '.rela.plt', which is not desirable.
+        RelocSections.push_back(RelocSec);
+    }
+    // Rename relocation sections according to their target sections.
+    for (RelocationSectionBase *RelocSec : RelocSections) {
+      auto Iter = RenamedSections.find(RelocSec->getSection());
+      if (Iter != RenamedSections.end())
+        RelocSec->Name = (RelocSec->getNamePrefix() + (*Iter)->Name).str();
     }
   }