Index: COFF/Writer.cpp
===================================================================
--- COFF/Writer.cpp
+++ COFF/Writer.cpp
@@ -187,6 +187,8 @@
   C->setRVA(Off);
   C->OutputSectionOff = Off;
   Off += C->getSize();
+  if (Off > UINT32_MAX)
+    error("section larger than 4 GiB: " + Name);
   Header.VirtualSize = Off;
   if (C->hasData())
     Header.SizeOfRawData = alignTo(Off, SectorSize);
Index: test/COFF/section-size.s
===================================================================
--- /dev/null
+++ test/COFF/section-size.s
@@ -0,0 +1,14 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-windows-msvc %s -o %tmain.obj
+# RUN: echo '.lcomm s, 0x80000000' | llvm-mc -filetype=obj -triple=x86_64-windows-msvc -o %t80000000_1.obj
+# RUN: cp %t80000000_1.obj %t80000000_2.obj
+# RUN: echo '.lcomm s, 0xffffffff' | llvm-mc -filetype=obj -triple=x86_64-windows-msvc -o %tffffffff.obj
+
+# Run: lld-link -entry:main %tmain.obj %tffffffff.obj -out:%t.exe
+
+# RUN: not lld-link -entry:main %tmain.obj %t80000000_1.obj %t80000000_2.obj -out:%t.exe 2>&1 | FileCheck %s
+# CHECK: error: section larger than 4 GiB: .bss
+
+.globl main
+main:
+	retq