Minor tweaks to PDB docs

[thakis]

Summary

• Fix a broken link
• Some spelling fixes
• Remove an unnecessary "amortized"
• Don't say "log(n) random access"; "random access" means O(1)
• Make MSF overview a bit more concise

[rnk]

lgtm with some suggestions

llvm/docs/PDB/TpiStream.rst

311

nit: I think O(log(n)) access would be clearer.

llvm/docs/PDB/index.rst

66

nit: "... not necessarily be contiguously laid out within the MSF container file." I think that's clearer, "aka fragmented" isn't necessary.

llvm/include/llvm/DebugInfo/PDB/Native/RawTypes.h

344

Revert whitespace-only change to a file?

[thakis]

Thanks! Landing.

llvm/docs/PDB/DbiStream.rst

   
 - **SymRecordStream** - The stream containing all CodeView symbol records used
   by the program.  This is used for deduplication, so that many different
   compilands can refer to the same symbols without having to include the full record
   content inside of each module stream.
   
 - **PdbDllRbld** - Unknown
 
-- **MFCTypeServerIndex** - The length of the :ref:dbi_mfc_type_server_substream
+- **MFCTypeServerIndex** - The length of the
+  :ref:`dbi_mfc_type_server_substream`.
 
 - **Flags** - A bitfield with the following layout, containing various
   information about how the program was built:
   
 .. code-block:: c++
 
   uint16_t WasIncrementallyLinked : 1;
   uint16_t ArePrivateSymbolsStripped : 1;

llvm/docs/PDB/TpiStream.rst

- **HashValueBufferOffset / HashValueBufferLength** - The offset and size within
   TPI stream (``TypeIndexEnd - TypeEndBegin``).  Thus, if ``HashBufferLength`` is
   not equal to ``(TypeIndexEnd - TypeEndBegin) * HashKeySize`` we can consider the
   PDB malformed.
 
 - **IndexOffsetBufferOffset / IndexOffsetBufferLength** - The offset and size
   within the TPI Hash Stream of the Type Index Offsets Buffer.  This is a list of
   pairs of uint32_t's where the first value is a :ref:`Type Index <type_indices>`
   and the second value is the offset in the type record data of the type with this
-  index.  This can be used to do a binary search followed bin a linear search to
-  get amortized O(log n) lookup by type index.
+  index.  This can be used to do a binary search followed by a linear search to
+  get O(log n) lookup by type index.
 
 - **HashAdjBufferOffset / HashAdjBufferLength** - The offset and size within
   the TPI hash stream of a serialized hash table whose keys are the hash values
   in the hash value buffer and whose values are type indices.  This appears to
   be useful in incremental linking scenarios, so that if a type is modified an
   entry can be created mapping the old hash value to the new type index so that
   a PDB file consumer can always have the most up to date version of the type
   without forcing the incremental linker to garbage collect and update
   references that point to the old version to now point to the new version.
   The layout of this hash table is described in :doc:`HashTable`.
 
 .. _tpi_records:
 
 CodeView Type Record List
 =========================
 Following the header, there are ``TypeRecordBytes`` bytes of data that represent a
 variable length array of :doc:`CodeView type records <CodeViewTypes>`.  The number
 of such records (e.g. the length of the array) can be determined by computing the
 value ``Header.TypeIndexEnd - Header.TypeIndexBegin``.
 
-log(n) random access is provided by way of the Type Index Offsets array (if present)
-described previously.
+log(n) access is provided by way of the Type Index Offsets array (if present)
+described previously.
 

llvm/docs/PDB/index.rst

.. toctree::
    HashTable
    CodeViewSymbols
    CodeViewTypes
 
 .. _msf:
 
 The MSF Container
 -----------------
-A PDB file is really just a special case of an MSF (Multi-Stream Format) file.
-An MSF file is actually a miniature "file system within a file".  It contains
-multiple streams (aka files) which can represent arbitrary data, and these
-streams are divided into blocks which may not necessarily be contiguously
-laid out within the file (aka fragmented).  Additionally, the MSF contains a
-stream directory (aka MFT) which describes how the streams (files) are laid
-out within the MSF.
+A PDB file is an MSF (Multi-Stream Format) file.  An MSF file is a "file system
+within a file".  It contains multiple streams (aka files) which can represent
+arbitrary data, and these streams are divided into blocks which may not
+necessarily be contiguously laid out within the file (aka fragmented).
+Additionally, the MSF contains a stream directory (aka MFT) which describes how
+the streams (files) are laid out within the MSF.
 
 For more information about the MSF container format, stream directory, and
 block layout, see :doc:`MsfFile`.
 
 .. _streams:
 
 Streams
 -------

llvm/include/llvm/DebugInfo/PDB/Native/RawTypes.h

struct SrcHeaderBlockEntry {
   support::ulittle32_t FileNI;   // String table index of file name.
   support::ulittle32_t ObjNI;    // String table index of object name.
   support::ulittle32_t VFileNI;  // String table index of virtual file name.
   uint8_t Compression;           // PDB_SourceCompression enumeration.
   uint8_t IsVirtual;             // Is this a virtual file (injected)?
   short Padding;                 // Pad to 4 bytes.
   char Reserved[8];
 };
-
 static_assert(sizeof(SrcHeaderBlockEntry) == 40, "Incorrect struct size!");
 
 } // namespace pdb
 } // namespace llvm
 
 #endif