Index: COFF/Chunks.cpp
===================================================================
--- COFF/Chunks.cpp
+++ COFF/Chunks.cpp
@@ -114,6 +114,8 @@
   uint32_t S = V < 0 ? 1 : 0;
   uint32_t J1 = ((~V >> 23) & 1) ^ S;
   uint32_t J2 = ((~V >> 22) & 1) ^ S;
+  if (!isInt<25>(V))
+    fatal("relocation out of range");
   or16(Off, (S << 10) | ((V >> 12) & 0x3ff));
   // The J1 and J2 bits are set in the opcode already, so mask them out
   // before or'ing in the new bits.