Auto merge of #76558 - tmandry:rollup-bskim2r, r=tmandry

Rollup of 7 pull requests

Successful merges:

 - #74787 (Move `rustllvm` into `compiler/rustc_llvm`)
 - #76458 (Add drain_filter method to HashMap and HashSet)
 - #76472 (rustbuild: don't set PYTHON_EXECUTABLE and WITH_POLLY cmake vars since they are no longer supported by llvm)
 - #76497 (Use intra-doc links in `core::ptr`)
 - #76500 (Add -Zgraphviz_dark_mode and monospace font fix)
 - #76543 (Document btree's unwrap_unchecked)
 - #76556 (Revert #76285)

Failed merges:

r? `@ghost`

1 files changed, 48 insertions, 0 deletions

diff --git a/compiler/rustc_llvm/llvm-wrapper/Linker.cpp b/compiler/rustc_llvm/llvm-wrapper/Linker.cpp
new file mode 100644
index 00000000000..8766e96f086
--- /dev/null
+++ b/compiler/rustc_llvm/llvm-wrapper/Linker.cpp
@@ -0,0 +1,48 @@
+#include "llvm/Linker/Linker.h"
+
+#include "LLVMWrapper.h"
+
+using namespace llvm;
+
+struct RustLinker {
+  Linker L;
+  LLVMContext &Ctx;
+
+  RustLinker(Module &M) :
+    L(M),
+    Ctx(M.getContext())
+  {}
+};
+
+extern "C" RustLinker*
+LLVMRustLinkerNew(LLVMModuleRef DstRef) {
+  Module *Dst = unwrap(DstRef);
+
+  return new RustLinker(*Dst);
+}
+
+extern "C" void
+LLVMRustLinkerFree(RustLinker *L) {
+  delete L;
+}
+
+extern "C" bool
+LLVMRustLinkerAdd(RustLinker *L, char *BC, size_t Len) {
+  std::unique_ptr<MemoryBuffer> Buf =
+      MemoryBuffer::getMemBufferCopy(StringRef(BC, Len));
+
+  Expected<std::unique_ptr<Module>> SrcOrError =
+      llvm::getLazyBitcodeModule(Buf->getMemBufferRef(), L->Ctx);
+  if (!SrcOrError) {
+    LLVMRustSetLastError(toString(SrcOrError.takeError()).c_str());
+    return false;
+  }
+
+  auto Src = std::move(*SrcOrError);
+
+  if (L->L.linkInModule(std::move(Src))) {
+    LLVMRustSetLastError("");
+    return false;
+  }
+  return true;
+}