diff --git a/lld/test/ELF/Inputs/large-files1.o.bz2 b/lld/test/ELF/Inputs/large-files1.o.bz2
new file mode 100644
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

literal 0
Hc$@<O00001

diff --git a/lld/test/ELF/Inputs/large-files2.o.bz2 b/lld/test/ELF/Inputs/large-files2.o.bz2
new file mode 100644
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

literal 0
Hc$@<O00001

diff --git a/lld/test/ELF/large-files.s b/lld/test/ELF/large-files.s
new file mode 100644
--- /dev/null
+++ b/lld/test/ELF/large-files.s
@@ -0,0 +1,102 @@
+# REQUIRES: x86
+
+## Show that LLD can create large output files, generated from multiple smaller
+## input files.
+
+# RUN: rm -rf %t.dir
+# RUN: mkdir -p %t.dir
+# RUN: cd %t.dir
+
+## These two inputs were created from the following assembly:
+##
+## .align 0x1000
+## .global SYMBOL1
+## SYMBOL1:
+## .space 0x80000000
+## SYMBOL2:
+## 
+## .data
+## .align 0x4000
+## SYMBOL3:
+## .byte 1
+## SYMBOL4:
+##
+## with the following instructions run on it:
+##
+## sed -e s/SYMBOL1/_start/g %s > t
+## sed -e s/SYMBOL2/end1/g t > t2
+## sed -e s/SYMBOL3/data1/g t2 > t3
+## sed -e s/SYMBOL4/enddata1/g t3 > t1.s
+## sed -e s/SYMBOL1/sym2/g %s > t
+## sed -e s/SYMBOL2/end2/g t > t2
+## sed -e s/SYMBOL3/data2/g t2 > t3
+## sed -e s/SYMBOL4/enddata2/g t3 > t2.s
+## llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu t1.s -o t1.o
+## llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu t2.s -o t2.o
+## bzip2 -c t1.o > %p/Inputs/large-files1.o.bz2
+## bzip2 -c t2.o > %p/Inputs/large-files2.o.bz2
+
+# RUN: bzip2 -kdc %p/Inputs/large-files1.o.bz2 > t1.o
+# RUN: bzip2 -kdc %p/Inputs/large-files2.o.bz2 > t2.o
+
+## Test a large output (>4GB) file can be created.
+# RUN: ld.lld t1.o t2.o -o t.elf
+# RUN: llvm-nm t.elf | FileCheck %s --check-prefixes=CHECK,DATA1
+
+## Clean up immediately so that we are not using more disk space than we need at
+## any one time.
+# RUN: rm t.elf
+
+## Test a large input can be used with a section size >4GB and a section at
+## offset >4GB.
+# RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o t3.o
+# RUN: ld.lld t1.o t2.o -o t.ro -r
+# RUN: ld.lld t.ro t3.o -o t.elf
+# RUN: llvm-nm t.elf | FileCheck %s --check-prefixes=CHECK,MORE
+# RUN: rm t.elf
+# RUN: rm t1.o
+# RUN: rm t2.o
+
+## Show that the link works when the large files are in an archive, for both
+## thin and regular archives.
+# RUN: llvm-ar rcsT t.a t.ro t3.o
+# RUN: ld.lld t.a --undefined _start --undefined sym2 --undefined sym3 -m elf_x86_64 -o t.elf
+# RUN: llvm-nm t.elf | FileCheck %s --check-prefixes=CHECK,MORE
+
+# RUN: rm t.elf
+# RUN: rm t.a
+
+# RUN: llvm-ar rcs t.a t.ro t3.o
+# RUN: rm t.ro
+# RUN: ld.lld t.a --undefined _start --undefined sym2 --undefined sym3 -m elf_x86_64 -o t.elf
+# RUN: llvm-nm t.elf | FileCheck %s --check-prefixes=CHECK,MORE
+
+## Clean up so that we do not have several GB of data leftover after this test
+## finishes.
+# RUN: cd ..
+# RUN: rm -rf %t.dir
+
+# CHECK:      0000000000202000 {{.*}} _start
+# CHECK-NEXT: 0000000100204000 {{.*}} data1
+# CHECK-NEXT: 0000000100208000 {{.*}} data2
+# MORE-NEXT:  000000010020c000 {{.*}} data3
+# CHECK-NEXT: 0000000080202000 {{.*}} end1
+# CHECK-NEXT: 0000000100202000 {{.*}} end2
+# MORE-NEXT:  0000000100202001 {{.*}} end3
+# CHECK-NEXT: 0000000100204001 {{.*}} enddata1
+# CHECK-NEXT: 0000000100208001 {{.*}} enddata2
+# MORE-NEXT:  000000010020c001 {{.*}} enddata3
+# CHECK-NEXT: 0000000080202000 {{.*}} sym2
+# MORE-NEXT:  0000000100202000 {{.*}} sym3
+
+.align 0x1000
+.global sym3
+sym3:
+    nop
+end3:
+
+.data
+.align 0x4000
+data3:
+    .byte 0
+enddata3:
diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -392,12 +392,8 @@
 }
 
 Expected<uint64_t> Archive::Child::getSize() const {
-  if (Parent->IsThin) {
-    Expected<uint32_t> Size = Header.getSize();
-    if (!Size)
-      return Size.takeError();
-    return Size.get();
-  }
+  if (Parent->IsThin)
+    return Header.getSize();
   return Data.size() - StartOfFile;
 }
 
@@ -437,7 +433,7 @@
     return isThinOrErr.takeError();
   bool isThin = isThinOrErr.get();
   if (!isThin) {
-    Expected<uint32_t> Size = getSize();
+    Expected<uint64_t> Size = getSize();
     if (!Size)
       return Size.takeError();
     return StringRef(Data.data() + StartOfFile, Size.get());