1 files changed, 29 insertions, 0 deletions
diff --git a/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp b/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
index 0a3b2b96ab4..bbcfbfca810 100644
--- a/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
+++ b/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
@@ -26,6 +26,19 @@ public:
 };
 }
 
+static void initializeFpmStreamLayout(const MSFLayout &Layout,
+                                      MSFStreamLayout &FpmLayout) {
+  uint32_t NumFpmIntervals = msf::getNumFpmIntervals(Layout);
+  support::ulittle32_t FpmBlock = Layout.SB->FreeBlockMapBlock;
+  assert(FpmBlock == 1 || FpmBlock == 2);
+  while (NumFpmIntervals > 0) {
+    FpmLayout.Blocks.push_back(FpmBlock);
+    FpmBlock += msf::getFpmIntervalLength(Layout);
+    --NumFpmIntervals;
+  }
+  FpmLayout.Length = msf::getFullFpmByteSize(Layout);
+}
+
 typedef std::pair<uint32_t, uint32_t> Interval;
 static Interval intersect(const Interval &I1, const Interval &I2) {
   return std::make_pair(std::max(I1.first, I2.first),
@@ -66,6 +79,14 @@ MappedBlockStream::createDirectoryStream(const MSFLayout &Layout,
   return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
 }
 
+std::unique_ptr<MappedBlockStream>
+MappedBlockStream::createFpmStream(const MSFLayout &Layout,
+                                   const ReadableStream &MsfData) {
+  MSFStreamLayout SL;
+  initializeFpmStreamLayout(Layout, SL);
+  return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
+}
+
 Error MappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
                                    ArrayRef<uint8_t> &Buffer) const {
   // Make sure we aren't trying to read beyond the end of the stream.
@@ -324,6 +345,14 @@ WritableMappedBlockStream::createDirectoryStream(
   return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
 }
 
+std::unique_ptr<WritableMappedBlockStream>
+WritableMappedBlockStream::createFpmStream(const MSFLayout &Layout,
+                                           const WritableStream &MsfData) {
+  MSFStreamLayout SL;
+  initializeFpmStreamLayout(Layout, SL);
+  return createStream(Layout.SB->BlockSize, Layout.SB->NumBlocks, SL, MsfData);
+}
+
 Error WritableMappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
                                            ArrayRef<uint8_t> &Buffer) const {
   return ReadInterface.readBytes(Offset, Size, Buffer);