[lld] [LLD][COFF] Handle --start-lib/--end-lib group in the same way as other archives (PR #136496)

[Martin Storsjö via llvm-commits]

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@@ -259,17 +244,24 @@ MemoryBufferRef LinkerDriver::takeBuffer(std::unique_ptr<MemoryBuffer> mb) {
 }
 
 void LinkerDriver::addBuffer(std::unique_ptr<MemoryBuffer> mb,
-                             bool wholeArchive, bool lazy) {
+                             bool wholeArchive,
+                             CmdLineArchive *inCmdLineArchive) {
   StringRef filename = mb->getBufferIdentifier();
 
   MemoryBufferRef mbref = takeBuffer(std::move(mb));
 
   // File type is detected by contents, not by file extension.
   switch (identify_magic(mbref.getBuffer())) {
   case file_magic::windows_resource:
+    assert(!inCmdLineArchive &&
+           "Cannot specify a RES file inside a --start-lib/--end-lib group.");
     resources.push_back(mbref);
     break;
   case file_magic::archive:
+    // FIXME: We could later support --start-lib/--end-lib groups, to allow for
+    // "extending" an existing archive/LIB.
+    assert(!inCmdLineArchive &&
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mstorsjo wrote:

As this case, and the resource one above, is quite possible to hit this as an unsuspecting user, we shouldn't be using assert for it; if we hit this in a release build without asserts, we don't want to run into essentially UB territory here - we probably should have a proper error for it. (We don't necessarily need to test for the error though.)

https://github.com/llvm/llvm-project/pull/136496