llmv-objdump/COFF: Print export table contents.

This patch adds the capability to dump export table contents. An example
output is this:

  Export Table:
   Ordinal      RVA  Name
         5   0x2008  exportfn1
         6   0x2010  exportfn2

By adding this feature to llvm-objdump, we will be able to use it to check
export table contents in LLD's tests. Currently we are doing binary
comparison in the tests, which is fragile and not readable to humans.

llvm-svn: 199358

1 files changed, 95 insertions, 3 deletions

diff --git a/llvm/lib/Object/COFFObjectFile.cpp b/llvm/lib/Object/COFFObjectFile.cpp
index dc8a718c7a3..4ad2e99629d 100644
--- a/llvm/lib/Object/COFFObjectFile.cpp
+++ b/llvm/lib/Object/COFFObjectFile.cpp
@@ -445,9 +445,27 @@ error_code COFFObjectFile::initImportTablePtr() {
     return ec;
   ImportDirectory = reinterpret_cast<
       const import_directory_table_entry *>(IntPtr);
+  return object_error::success;
+}
 
-  // It's an error if there's no section containing the Import Table RVA.
-  return object_error::parse_failed;
+// Find the export table.
+error_code COFFObjectFile::initExportTablePtr() {
+  // First, we get the RVA of the export table. If the file lacks a pointer to
+  // the export table, do nothing.
+  const data_directory *DataEntry;
+  if (getDataDirectory(COFF::EXPORT_TABLE, DataEntry))
+    return object_error::success;
+
+  // Do nothing if the pointer to export table is NULL.
+  if (DataEntry->RelativeVirtualAddress == 0)
+    return object_error::success;
+
+  uint32_t ExportTableRva = DataEntry->RelativeVirtualAddress;
+  uintptr_t IntPtr = 0;
+  if (error_code EC = getRvaPtr(ExportTableRva, IntPtr))
+    return EC;
+  ExportDirectory = reinterpret_cast<const export_directory_table_entry *>(IntPtr);
+  return object_error::success;
 }
 
 COFFObjectFile::COFFObjectFile(MemoryBuffer *Object, error_code &ec)
@@ -460,7 +478,8 @@ COFFObjectFile::COFFObjectFile(MemoryBuffer *Object, error_code &ec)
   , StringTable(0)
   , StringTableSize(0)
   , ImportDirectory(0)
-  , NumberOfImportDirectory(0) {
+  , NumberOfImportDirectory(0)
+  , ExportDirectory(0) {
   // Check that we at least have enough room for a header.
   if (!checkSize(Data, ec, sizeof(coff_file_header))) return;
 
@@ -521,6 +540,10 @@ COFFObjectFile::COFFObjectFile(MemoryBuffer *Object, error_code &ec)
   if ((ec = initImportTablePtr()))
     return;
 
+  // Initialize the pointer to the export table.
+  if ((ec = initExportTablePtr()))
+    return;
+
   ec = object_error::success;
 }
 
@@ -572,6 +595,19 @@ import_directory_iterator COFFObjectFile::import_directory_end() const {
       ImportDirectoryEntryRef(ImportDirectory, NumberOfImportDirectory, this));
 }
 
+export_directory_iterator COFFObjectFile::export_directory_begin() const {
+  return export_directory_iterator(
+      ExportDirectoryEntryRef(ExportDirectory, 0, this));
+}
+
+export_directory_iterator COFFObjectFile::export_directory_end() const {
+  if (ExportDirectory == 0)
+    return export_directory_iterator(ExportDirectoryEntryRef(0, 0, this));
+  ExportDirectoryEntryRef ref(ExportDirectory,
+                              ExportDirectory->AddressTableEntries, this);
+  return export_directory_iterator(ref);
+}
+
 section_iterator COFFObjectFile::begin_sections() const {
   DataRefImpl ret;
   ret.p = reinterpret_cast<uintptr_t>(SectionTable);
@@ -910,6 +946,62 @@ error_code ImportDirectoryEntryRef::getImportLookupEntry(
   return object_error::success;
 }
 
+bool ExportDirectoryEntryRef::
+operator==(const ExportDirectoryEntryRef &Other) const {
+  return ExportTable == Other.ExportTable && Index == Other.Index;
+}
+
+error_code
+ExportDirectoryEntryRef::getNext(ExportDirectoryEntryRef &Result) const {
+  Result = ExportDirectoryEntryRef(ExportTable, Index + 1, OwningObject);
+  return object_error::success;
+}
+
+// Returns the export ordinal of the current export symbol.
+error_code ExportDirectoryEntryRef::getOrdinal(uint32_t &Result) const {
+  Result = ExportTable->OrdinalBase + Index;
+  return object_error::success;
+}
+
+// Returns the address of the current export symbol.
+error_code ExportDirectoryEntryRef::getExportRVA(uint32_t &Result) const {
+  uintptr_t IntPtr = 0;
+  if (error_code EC = OwningObject->getRvaPtr(
+          ExportTable->ExportAddressTableRVA, IntPtr))
+    return EC;
+  const export_address_table_entry *entry = reinterpret_cast<const export_address_table_entry *>(IntPtr);
+  Result = entry[Index].ExportRVA;
+  return object_error::success;
+}
+
+// Returns the name of the current export symbol. If the symbol is exported only
+// by ordinal, the empty string is set as a result.
+error_code ExportDirectoryEntryRef::getName(StringRef &Result) const {
+  uintptr_t IntPtr = 0;
+  if (error_code EC = OwningObject->getRvaPtr(
+          ExportTable->OrdinalTableRVA, IntPtr))
+    return EC;
+  const ulittle16_t *Start = reinterpret_cast<const ulittle16_t *>(IntPtr);
+
+  uint32_t NumEntries = ExportTable->NumberOfNamePointers;
+  int Offset = 0;
+  for (const ulittle16_t *I = Start, *E = Start + NumEntries;
+       I < E; ++I, ++Offset) {
+    if (*I != Index)
+      continue;
+    if (error_code EC = OwningObject->getRvaPtr(
+            ExportTable->NamePointerRVA, IntPtr))
+      return EC;
+    const ulittle32_t *NamePtr = reinterpret_cast<const ulittle32_t *>(IntPtr);
+    if (error_code EC = OwningObject->getRvaPtr(NamePtr[Offset], IntPtr))
+      return EC;
+    Result = StringRef(reinterpret_cast<const char *>(IntPtr));
+    return object_error::success;
+  }
+  Result = "";
+  return object_error::success;
+}
+
 namespace llvm {
 ObjectFile *ObjectFile::createCOFFObjectFile(MemoryBuffer *Object) {
   error_code ec;