commit b927e02e1b4034eacfe2222ab6a951853ff12513
author Zachary Turner <zturner@google.com> Fri Jul 15 22:17:19 2016 +0000
committer Zachary Turner <zturner@google.com> Fri Jul 15 22:17:19 2016 +0000
tree 66fc0403f9df0e4e08e032e1bab66a2275d2c072
parent 5e534c7fb357a157793e9a47c8a00880bdb18799

[pdb] Teach MsfBuilder and other classes about the Free Page Map.

Block 1 and 2 of an MSF file are bit vectors that represent the
list of blocks allocated and free in the file.  We had been using
these blocks to write stream data and other data, so we mark them
as the free page map now.  We don't yet serialize these pages to
the disk, but at least we make a note of what it is, and avoid
writing random data to them.

Doing this also necessitated cleaning up some of the tests to be
more general and hardcode fewer values, which is nice.

llvm-svn: 275629

llvm/lib/DebugInfo/PDB/Raw/MsfBuilder.cpp

diff --git a/llvm/lib/DebugInfo/PDB/Raw/MsfBuilder.cpp b/llvm/lib/DebugInfo/PDB/Raw/MsfBuilder.cpp
index fecefbf..16b086b 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/MsfBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/MsfBuilder.cpp
@@ -17,15 +17,21 @@
 
 namespace {
 const uint32_t kSuperBlockBlock = 0;
-const uint32_t kDefaultBlockMapAddr = 1;
+const uint32_t kFreePageMap0Block = 1;
+const uint32_t kFreePageMap1Block = 2;
+const uint32_t kNumReservedPages = 3;
+
+const uint32_t kDefaultBlockMapAddr = kNumReservedPages;
 }
 
 MsfBuilder::MsfBuilder(uint32_t BlockSize, uint32_t MinBlockCount, bool CanGrow,
                        BumpPtrAllocator &Allocator)
     : Allocator(Allocator), IsGrowable(CanGrow), BlockSize(BlockSize),
       MininumBlocks(MinBlockCount), BlockMapAddr(kDefaultBlockMapAddr),
-      FreeBlocks(std::max(MinBlockCount, 2U), true) {
+      FreeBlocks(MinBlockCount, true) {
   FreeBlocks[kSuperBlockBlock] = false;
+  FreeBlocks[kFreePageMap0Block] = false;
+  FreeBlocks[kFreePageMap1Block] = false;
   FreeBlocks[BlockMapAddr] = false;
 }
 
@@ -36,7 +42,9 @@
     return make_error<RawError>(raw_error_code::unspecified,
                                 "The requested block size is unsupported");
 
-  return MsfBuilder(BlockSize, MinBlockCount, CanGrow, Allocator);
+  return MsfBuilder(BlockSize,
+                    std::max(MinBlockCount, msf::getMinimumBlockCount()),
+                    CanGrow, Allocator);
 }
 
 Error MsfBuilder::setBlockMapAddr(uint32_t Addr) {
@@ -59,7 +67,7 @@
   return Error::success();
 }
 
-void MsfBuilder::setUnknown0(uint32_t Unk0) { Unknown0 = Unk0; }
+void MsfBuilder::setFreePageMap(uint32_t Fpm) { FreePageMap = Fpm; }
 
 void MsfBuilder::setUnknown1(uint32_t Unk1) { Unknown1 = Unk1; }
 
@@ -217,7 +225,7 @@
   L.SB->BlockMapAddr = BlockMapAddr;
   L.SB->BlockSize = BlockSize;
   L.SB->NumDirectoryBytes = computeDirectoryByteSize();
-  L.SB->Unknown0 = Unknown0;
+  L.SB->FreeBlockMapBlock = FreePageMap;
   L.SB->Unknown1 = Unknown1;
 
   uint32_t NumDirectoryBlocks =

llvm/lib/DebugInfo/PDB/Raw/PDBFile.cpp

diff --git a/llvm/lib/DebugInfo/PDB/Raw/PDBFile.cpp b/llvm/lib/DebugInfo/PDB/Raw/PDBFile.cpp
index 8b09dc5..9501675 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/PDBFile.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/PDBFile.cpp
@@ -42,7 +42,7 @@
 
 uint32_t PDBFile::getBlockSize() const { return SB->BlockSize; }
 
-uint32_t PDBFile::getUnknown0() const { return SB->Unknown0; }
+uint32_t PDBFile::getFreeBlockMapBlock() const { return SB->FreeBlockMapBlock; }
 
 uint32_t PDBFile::getBlockCount() const { return SB->NumBlocks; }
 

llvm/lib/DebugInfo/PDB/Raw/PDBFileBuilder.cpp

diff --git a/llvm/lib/DebugInfo/PDB/Raw/PDBFileBuilder.cpp b/llvm/lib/DebugInfo/PDB/Raw/PDBFileBuilder.cpp
index b1ae760..9063fd6 100644
--- a/llvm/lib/DebugInfo/PDB/Raw/PDBFileBuilder.cpp
+++ b/llvm/lib/DebugInfo/PDB/Raw/PDBFileBuilder.cpp
@@ -37,9 +37,9 @@
   auto &MsfResult = *ExpectedMsf;
   if (auto EC = MsfResult.setBlockMapAddr(Super.BlockMapAddr))
     return EC;
-  MsfResult.setUnknown0(Super.Unknown0);
-  MsfResult.setUnknown1(Super.Unknown1);
   Msf = llvm::make_unique<MsfBuilder>(std::move(MsfResult));
+  Msf->setFreePageMap(Super.FreeBlockMapBlock);
+  Msf->setUnknown1(Super.Unknown1);
   return Error::success();
 }