Index: include/llvm/DebugInfo/PDB/Raw/PDBFile.h
===================================================================
--- include/llvm/DebugInfo/PDB/Raw/PDBFile.h
+++ include/llvm/DebugInfo/PDB/Raw/PDBFile.h
@@ -47,6 +47,7 @@
   ~PDBFile() override;
 
   uint32_t getFreeBlockMapBlock() const;
+  Expected<std::vector<uint32_t>> getUsedBlockList() const;
   uint32_t getUnknown1() const;
 
   uint32_t getBlockSize() const override;
Index: lib/DebugInfo/PDB/Raw/PDBFile.cpp
===================================================================
--- lib/DebugInfo/PDB/Raw/PDBFile.cpp
+++ lib/DebugInfo/PDB/Raw/PDBFile.cpp
@@ -46,6 +46,22 @@
   return ContainerLayout.SB->FreeBlockMapBlock;
 }
 
+// Returns a vector of used page indices, which is a complement of Free
+// Page Map contents. (The reason why we are returning a complement is
+// because otherwise the result would be large, as most pages are unused.)
+Expected<std::vector<uint32_t>> PDBFile::getUsedBlockList() const {
+  uint64_t Offset = ContainerLayout.SB->FreeBlockMapBlock * getBlockSize();
+  ArrayRef<uint8_t> Result;
+  if (auto EC = Buffer->readBytes(Offset, getBlockSize(), Result))
+    return std::move(EC);
+
+  std::vector<uint32_t> Vec;
+  for (uint32_t I = 0, E = getBlockSize() * 8; I != E; ++I)
+    if ((Result[I / 8] & (1 << (I % 8))) == 0)
+      Vec.push_back(I);
+  return Vec;
+}
+
 uint32_t PDBFile::getBlockCount() const {
   return ContainerLayout.SB->NumBlocks;
 }
Index: test/DebugInfo/PDB/pdbdump-headers.test
===================================================================
--- test/DebugInfo/PDB/pdbdump-headers.test
+++ test/DebugInfo/PDB/pdbdump-headers.test
@@ -2,7 +2,7 @@
 ; RUN:              -sym-record-bytes -publics -module-files -stream-name=/names \
 ; RUN:              -stream-summary -stream-blocks -ipi-records -ipi-record-bytes \
 ; RUN:              -section-contribs -section-map -section-headers -line-info \
-; RUN:              -tpi-hash -fpo %p/Inputs/empty.pdb | FileCheck -check-prefix=EMPTY %s
+; RUN:              -tpi-hash -fpo -fpm %p/Inputs/empty.pdb | FileCheck -check-prefix=EMPTY %s
 ; RUN: llvm-pdbdump raw -all %p/Inputs/empty.pdb | FileCheck -check-prefix=ALL %s
 ; RUN: llvm-pdbdump raw -headers -stream-name=/names -modules -module-files \
 ; RUN:              %p/Inputs/big-read.pdb | FileCheck -check-prefix=BIG %s
@@ -38,6 +38,7 @@
 ; EMPTY-NEXT:   Stream 15: [TPI Hash] (308 bytes)
 ; EMPTY-NEXT:   Stream 16: [IPI Hash] (68 bytes)
 ; EMPTY-NEXT: ]
+; EMPTY-NEXT: Used Page Map: [0, 1, 2, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]
 ; EMPTY-NEXT: StreamBlocks [
 ; EMPTY-NEXT:   Stream 0: [8]
 ; EMPTY-NEXT:   Stream 1: [19]
@@ -973,6 +974,7 @@
 ; ALL:   Stream 15: [TPI Hash] (308 bytes)
 ; ALL:   Stream 16: [IPI Hash] (68 bytes)
 ; ALL: ]
+; ALL: Used Page Map: [0, 1, 2, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24]
 ; ALL: StreamBlocks [
 ; ALL:   Stream 0: [8]
 ; ALL:   Stream 1: [19]
Index: tools/llvm-pdbdump/LLVMOutputStyle.h
===================================================================
--- tools/llvm-pdbdump/LLVMOutputStyle.h
+++ tools/llvm-pdbdump/LLVMOutputStyle.h
@@ -26,6 +26,7 @@
 private:
   Error dumpFileHeaders();
   Error dumpStreamSummary();
+  Error dumpFreePageMap();
   Error dumpStreamBlocks();
   Error dumpStreamData();
   Error dumpInfoStream();
Index: tools/llvm-pdbdump/LLVMOutputStyle.cpp
===================================================================
--- tools/llvm-pdbdump/LLVMOutputStyle.cpp
+++ tools/llvm-pdbdump/LLVMOutputStyle.cpp
@@ -50,6 +50,9 @@
   if (auto EC = dumpStreamSummary())
     return EC;
 
+  if (auto EC = dumpFreePageMap())
+    return EC;
+
   if (auto EC = dumpStreamBlocks())
     return EC;
 
@@ -234,6 +237,16 @@
   return Error::success();
 }
 
+Error LLVMOutputStyle::dumpFreePageMap() {
+  if (!opts::raw::DumpFreePageMap)
+    return Error::success();
+  auto List = File.getUsedBlockList();
+  if (!List)
+    return List.takeError();
+  P.printList("Used Page Map", *List);
+  return Error::success();
+}
+
 Error LLVMOutputStyle::dumpStreamBlocks() {
   if (!opts::raw::DumpStreamBlocks)
     return Error::success();
Index: tools/llvm-pdbdump/llvm-pdbdump.h
===================================================================
--- tools/llvm-pdbdump/llvm-pdbdump.h
+++ tools/llvm-pdbdump/llvm-pdbdump.h
@@ -37,6 +37,7 @@
 extern llvm::cl::opt<bool> DumpHeaders;
 extern llvm::cl::opt<bool> DumpStreamBlocks;
 extern llvm::cl::opt<bool> DumpStreamSummary;
+extern llvm::cl::opt<bool> DumpFreePageMap;
 extern llvm::cl::opt<bool> DumpTpiHash;
 extern llvm::cl::opt<bool> DumpTpiRecordBytes;
 extern llvm::cl::opt<bool> DumpTpiRecords;
Index: tools/llvm-pdbdump/llvm-pdbdump.cpp
===================================================================
--- tools/llvm-pdbdump/llvm-pdbdump.cpp
+++ tools/llvm-pdbdump/llvm-pdbdump.cpp
@@ -167,6 +167,8 @@
 cl::opt<bool> DumpStreamSummary("stream-summary",
                                 cl::desc("dump summary of the PDB streams"),
                                 cl::cat(MsfOptions), cl::sub(RawSubcommand));
+cl::opt<bool> DumpFreePageMap("fpm", cl::desc("dump free page bitmap"),
+                              cl::cat(MsfOptions), cl::sub(RawSubcommand));
 
 // TYPE OPTIONS
 cl::opt<bool>
@@ -542,6 +544,7 @@
     opts::raw::DumpPublics = true;
     opts::raw::DumpSectionHeaders = true;
     opts::raw::DumpStreamSummary = true;
+    opts::raw::DumpFreePageMap = true;
     opts::raw::DumpStreamBlocks = true;
     opts::raw::DumpTpiRecords = true;
     opts::raw::DumpTpiHash = true;