Index: lld/ELF/Config.h
===================================================================
--- lld/ELF/Config.h
+++ lld/ELF/Config.h
@@ -175,6 +175,7 @@
   llvm::Optional<uint64_t> ImageBase;
   uint64_t MaxPageSize;
   uint64_t ZStackSize;
+  unsigned BloomFilterBits;
   unsigned LTOPartitions;
   unsigned LTOO;
   unsigned Optimize;
Index: lld/ELF/Driver.cpp
===================================================================
--- lld/ELF/Driver.cpp
+++ lld/ELF/Driver.cpp
@@ -594,6 +594,7 @@
   Config->AllowMultipleDefinition =
       Args.hasArg(OPT_allow_multiple_definition) || hasZOption(Args, "muldefs");
   Config->AuxiliaryList = args::getStrings(Args, OPT_auxiliary);
+  Config->BloomFilterBits = args::getInteger(Args, OPT_bloom_filter_bits, 8);
   Config->Bsymbolic = Args.hasArg(OPT_Bsymbolic);
   Config->BsymbolicFunctions = Args.hasArg(OPT_Bsymbolic_functions);
   Config->Chroot = Args.getLastArgValue(OPT_chroot);
Index: lld/ELF/Options.td
===================================================================
--- lld/ELF/Options.td
+++ lld/ELF/Options.td
@@ -13,6 +13,8 @@
 
 def auxiliary: S<"auxiliary">, HelpText<"Set DT_AUXILIARY field to the specified name">;
 
+defm bloom_filter_bits: Eq<"bloom-filter-bits">;
+
 def Bsymbolic: F<"Bsymbolic">, HelpText<"Bind defined symbols locally">;
 
 def Bsymbolic_functions: F<"Bsymbolic-functions">,
Index: lld/ELF/SyntheticSections.cpp
===================================================================
--- lld/ELF/SyntheticSections.cpp
+++ lld/ELF/SyntheticSections.cpp
@@ -1706,7 +1706,7 @@
   if (Symbols.empty())
     MaskWords = 1;
   else
-    MaskWords = NextPowerOf2((Symbols.size() - 1) / Config->Wordsize);
+    MaskWords = NextPowerOf2(Symbols.size() * Config->BloomFilterBits / Config->Wordsize / 8);
 
   Size = 16;                            // Header
   Size += Config->Wordsize * MaskWords; // Bloom filter
@@ -1749,6 +1749,14 @@
     Val |= uint64_t(1) << ((Sym.Hash >> getShift2()) % C);
     writeUint(Buf + I * Config->Wordsize, Val);
   }
+
+  ArrayRef<uint8_t> Arr(Buf, Config->Wordsize * MaskWords);
+  message("Bloom filter size in bits: " + Twine(Arr.size() * 8));
+
+  size_t Ones = 0;
+  for (uint8_t Byte : Arr)
+    Ones += __builtin_popcount(Byte);
+  message(" # of 1 bits: " + Twine(Ones) + " (" + Twine((int)((double)Ones / Arr.size() * 8)) + "%)");
 }
 
 void GnuHashTableSection::writeHashTable(uint8_t *Buf) {