1 files changed, 27 insertions, 24 deletions

diff --git a/gnu/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp b/gnu/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
index e45f4ae0ed9..dec28eb3069 100644
--- a/gnu/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
+++ b/gnu/llvm/lib/DebugInfo/MSF/MappedBlockStream.cpp
@@ -11,7 +11,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/DebugInfo/MSF/MSFCommon.h"
-#include "llvm/DebugInfo/MSF/MSFStreamLayout.h"
+#include "llvm/Support/BinaryStreamWriter.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/MathExtras.h"
@@ -36,19 +36,6 @@ public:
 
 } // end anonymous namespace
 
-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);
-}
-
 using Interval = std::pair<uint32_t, uint32_t>;
 
 static Interval intersect(const Interval &I1, const Interval &I2) {
@@ -95,15 +82,14 @@ std::unique_ptr<MappedBlockStream>
 MappedBlockStream::createFpmStream(const MSFLayout &Layout,
                                    BinaryStreamRef MsfData,
                                    BumpPtrAllocator &Allocator) {
-  MSFStreamLayout SL;
-  initializeFpmStreamLayout(Layout, SL);
+  MSFStreamLayout SL(getFpmStreamLayout(Layout));
   return createStream(Layout.SB->BlockSize, SL, MsfData, Allocator);
 }
 
 Error MappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
                                    ArrayRef<uint8_t> &Buffer) {
   // Make sure we aren't trying to read beyond the end of the stream.
-  if (auto EC = checkOffset(Offset, Size))
+  if (auto EC = checkOffsetForRead(Offset, Size))
     return EC;
 
   if (tryReadContiguously(Offset, Size, Buffer))
@@ -181,7 +167,7 @@ Error MappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
 Error MappedBlockStream::readLongestContiguousChunk(uint32_t Offset,
                                                     ArrayRef<uint8_t> &Buffer) {
   // Make sure we aren't trying to read beyond the end of the stream.
-  if (auto EC = checkOffset(Offset, 1))
+  if (auto EC = checkOffsetForRead(Offset, 1))
     return EC;
 
   uint32_t First = Offset / BlockSize;
@@ -257,7 +243,7 @@ Error MappedBlockStream::readBytes(uint32_t Offset,
   uint32_t OffsetInBlock = Offset % BlockSize;
 
   // Make sure we aren't trying to read beyond the end of the stream.
-  if (auto EC = checkOffset(Offset, Buffer.size()))
+  if (auto EC = checkOffsetForRead(Offset, Buffer.size()))
     return EC;
 
   uint32_t BytesLeft = Buffer.size();
@@ -362,10 +348,27 @@ WritableMappedBlockStream::createDirectoryStream(
 std::unique_ptr<WritableMappedBlockStream>
 WritableMappedBlockStream::createFpmStream(const MSFLayout &Layout,
                                            WritableBinaryStreamRef MsfData,
-                                           BumpPtrAllocator &Allocator) {
-  MSFStreamLayout SL;
-  initializeFpmStreamLayout(Layout, SL);
-  return createStream(Layout.SB->BlockSize, SL, MsfData, Allocator);
+                                           BumpPtrAllocator &Allocator,
+                                           bool AltFpm) {
+  // We only want to give the user a stream containing the bytes of the FPM that
+  // are actually valid, but we want to initialize all of the bytes, even those
+  // that come from reserved FPM blocks where the entire block is unused.  To do
+  // this, we first create the full layout, which gives us a stream with all
+  // bytes and all blocks, and initialize everything to 0xFF (all blocks in the
+  // file are unused).  Then we create the minimal layout (which contains only a
+  // subset of the bytes previously initialized), and return that to the user.
+  MSFStreamLayout MinLayout(getFpmStreamLayout(Layout, false, AltFpm));
+
+  MSFStreamLayout FullLayout(getFpmStreamLayout(Layout, true, AltFpm));
+  auto Result =
+      createStream(Layout.SB->BlockSize, FullLayout, MsfData, Allocator);
+  if (!Result)
+    return Result;
+  std::vector<uint8_t> InitData(Layout.SB->BlockSize, 0xFF);
+  BinaryStreamWriter Initializer(*Result);
+  while (Initializer.bytesRemaining() > 0)
+    cantFail(Initializer.writeBytes(InitData));
+  return createStream(Layout.SB->BlockSize, MinLayout, MsfData, Allocator);
 }
 
 Error WritableMappedBlockStream::readBytes(uint32_t Offset, uint32_t Size,
@@ -385,7 +388,7 @@ uint32_t WritableMappedBlockStream::getLength() {
 Error WritableMappedBlockStream::writeBytes(uint32_t Offset,
                                             ArrayRef<uint8_t> Buffer) {
   // Make sure we aren't trying to write beyond the end of the stream.
-  if (auto EC = checkOffset(Offset, Buffer.size()))
+  if (auto EC = checkOffsetForWrite(Offset, Buffer.size()))
     return EC;
 
   uint32_t BlockNum = Offset / getBlockSize();