[PECOFF] Emit the delay-import table

This is a partial patch to emit the delay-import table. With this,
LLD is now able to emit the table that llvm-readobj can read and
dump.

The table lacks a few fields, such as the address of HMODULE, the
import address table, etc. They'll be added in subsequent patches.

llvm-svn: 219384

1 files changed, 35 insertions, 0 deletions

diff --git a/lld/lib/ReaderWriter/PECOFF/IdataPass.h b/lld/lib/ReaderWriter/PECOFF/IdataPass.h
index 0adf2dd881e..efba5835e1d 100644
--- a/lld/lib/ReaderWriter/PECOFF/IdataPass.h
+++ b/lld/lib/ReaderWriter/PECOFF/IdataPass.h
@@ -126,6 +126,41 @@ public:
   StringRef customSectionName() const override { return ".idata.d"; }
 };
 
+/// The class for the the delay-load import table.
+class DelayImportDirectoryAtom : public IdataAtom {
+public:
+  DelayImportDirectoryAtom(
+      IdataContext &context, StringRef loadName,
+      const std::vector<COFFSharedLibraryAtom *> &sharedAtoms)
+      : IdataAtom(context, createContent()) {
+    addRelocations(context, loadName, sharedAtoms);
+  }
+
+  StringRef customSectionName() const override { return ".didat.d"; }
+
+private:
+  std::vector<uint8_t> createContent();
+  void addRelocations(IdataContext &context, StringRef loadName,
+                      const std::vector<COFFSharedLibraryAtom *> &sharedAtoms);
+
+  mutable llvm::BumpPtrAllocator _alloc;
+};
+
+/// Terminator of the delay-load import table. The content of this atom is all
+/// zero.
+class DelayNullImportDirectoryAtom : public IdataAtom {
+public:
+  explicit DelayNullImportDirectoryAtom(IdataContext &context)
+      : IdataAtom(context, createContent()) {}
+  StringRef customSectionName() const override { return ".didat.d"; }
+
+private:
+  std::vector<uint8_t> createContent() const {
+    return std::vector<uint8_t>(
+        sizeof(llvm::object::delay_import_directory_table_entry), 0);
+  }
+};
+
 } // namespace idata
 
 class IdataPass : public lld::Pass {