obj2yaml, yaml2obj: Add support for COFF executables

In support of serializing executables, obj2yaml now records the virtual address
and size of sections.  It also serializes whatever we strictly need from
the PE header, it expects that it can reconstitute everything else via
inference.

yaml2obj can reconstitute a fully linked executable.

In order to get executables correctly serialized/deserialized, other
bugs were fixed as a circumstance.  We now properly respect file and
section alignments.  We also avoid writing out string tables unless they
are strictly necessary.

llvm-svn: 221975

1 files changed, 9 insertions, 5 deletions

diff --git a/llvm/lib/Object/COFFObjectFile.cpp b/llvm/lib/Object/COFFObjectFile.cpp
index 68bf7fd..a1fc51a 100644
--- a/llvm/lib/Object/COFFObjectFile.cpp
+++ b/llvm/lib/Object/COFFObjectFile.cpp
@@ -460,9 +460,9 @@ std::error_code COFFObjectFile::initSymbolTablePtr() {
   // Find string table. The first four byte of the string table contains the
   // total size of the string table, including the size field itself. If the
   // string table is empty, the value of the first four byte would be 4.
-  const uint8_t *StringTableAddr =
-      base() + getPointerToSymbolTable() +
-      getNumberOfSymbols() * getSymbolTableEntrySize();
+  uint32_t StringTableOffset = getPointerToSymbolTable() +
+                               getNumberOfSymbols() * getSymbolTableEntrySize();
+  const uint8_t *StringTableAddr = base() + StringTableOffset;
   const ulittle32_t *StringTableSizePtr;
   if (std::error_code EC = getObject(StringTableSizePtr, Data, StringTableAddr))
     return EC;
@@ -826,13 +826,17 @@ std::error_code
 COFFObjectFile::getDataDirectory(uint32_t Index,
                                  const data_directory *&Res) const {
   // Error if if there's no data directory or the index is out of range.
-  if (!DataDirectory)
+  if (!DataDirectory) {
+    Res = nullptr;
     return object_error::parse_failed;
+  }
   assert(PE32Header || PE32PlusHeader);
   uint32_t NumEnt = PE32Header ? PE32Header->NumberOfRvaAndSize
                                : PE32PlusHeader->NumberOfRvaAndSize;
-  if (Index > NumEnt)
+  if (Index >= NumEnt) {
+    Res = nullptr;
     return object_error::parse_failed;
+  }
   Res = &DataDirectory[Index];
   return object_error::success;
 }