[Object] Skip section offset checking for /<XFGHASHMAP>/

Starting from Windows SDK for Windows 11 (10.0.22000.x), all the system
libraries (.lib files) contain a section with the '/<XFGHASHMAP>/' name.
This looks like the libraries are built with control flow guard enabled:
https://docs.microsoft.com/en-us/cpp/build/reference/guard-enable-control-flow-guard?view=msvc-170

To let the LLVM tools (llvm-ar, llvm-lib) work with these libraries,
this patch just skips the section offset check for sections with the
'/<XFGHASHMAP>/' name.

Closes: llvm/llvm-project#53814

Signed-off-by: Pavel Samolysov <pavel.samolysov@intel.com>

Reviewed By: jhenderson, thieta

Differential Revision: https://reviews.llvm.org/D120645

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Object/Archive.cpp b/llvm/lib/Object/Archive.cpp
index 3d615f8..3960971 100644
--- a/llvm/lib/Object/Archive.cpp
+++ b/llvm/lib/Object/Archive.cpp
@@ -256,6 +256,10 @@ Expected<StringRef> ArchiveMemberHeader::getName(uint64_t Size) const {
       return Name;
     if (Name.size() == 2 && Name[1] == '/') // String table.
       return Name;
+    // System libraries from the Windows SDK for Windows 11 contain this symbol.
+    // It looks like a CFG guard: we just skip it for now.
+    if (Name.equals("/<XFGHASHMAP>/"))
+      return Name;
     // It's a long name.
     // Get the string table offset.
     std::size_t StringOffset;