[pdb] Introduce MsfBuilder for laying out PDB files.

Reviewed by: ruiu
Differential Revision: https://reviews.llvm.org/D22308

llvm-svn: 275611

1 files changed, 48 insertions, 0 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Raw/MsfCommon.cpp b/llvm/lib/DebugInfo/PDB/Raw/MsfCommon.cpp
new file mode 100644
index 00000000000..5d97f33e110
--- /dev/null
+++ b/llvm/lib/DebugInfo/PDB/Raw/MsfCommon.cpp
@@ -0,0 +1,48 @@
+//===- MsfCommon.cpp - Common types and functions for MSF files -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/PDB/Raw/MsfCommon.h"
+#include "llvm/DebugInfo/PDB/Raw/RawError.h"
+
+using namespace llvm;
+using namespace llvm::pdb::msf;
+
+Error llvm::pdb::msf::validateSuperBlock(const SuperBlock &SB) {
+  // Check the magic bytes.
+  if (std::memcmp(SB.MagicBytes, Magic, sizeof(Magic)) != 0)
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "MSF magic header doesn't match");
+
+  if (!isValidBlockSize(SB.BlockSize))
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "Unsupported block size.");
+
+  // We don't support directories whose sizes aren't a multiple of four bytes.
+  if (SB.NumDirectoryBytes % sizeof(support::ulittle32_t) != 0)
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "Directory size is not multiple of 4.");
+
+  // The number of blocks which comprise the directory is a simple function of
+  // the number of bytes it contains.
+  uint64_t NumDirectoryBlocks =
+      bytesToBlocks(SB.NumDirectoryBytes, SB.BlockSize);
+
+  // The directory, as we understand it, is a block which consists of a list of
+  // block numbers.  It is unclear what would happen if the number of blocks
+  // couldn't fit on a single block.
+  if (NumDirectoryBlocks > SB.BlockSize / sizeof(support::ulittle32_t))
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "Too many directory blocks.");
+
+  if (SB.BlockMapAddr == 0)
+    return make_error<RawError>(raw_error_code::corrupt_file,
+                                "Block 0 is reserved");
+
+  return Error::success();
+}