[clang] [clang-repl] Implement LoadDynamicLibrary for clang-repl wasm use cases (PR #133037)

[Anutosh Bhat via cfe-commits]

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@@ -711,6 +712,14 @@ llvm::Error Interpreter::Undo(unsigned N) {
 }
 
 llvm::Error Interpreter::LoadDynamicLibrary(const char *name) {
+#ifdef __EMSCRIPTEN__
+  void *handle = dlopen(name, RTLD_NOW | RTLD_GLOBAL);
+  if (!handle) {
+    llvm::errs() << dlerror() << '\n';
+    return llvm::make_error<llvm::StringError>("Failed to load dynamic library",
+                                               llvm::inconvertibleErrorCode());
+  }
+#else
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anutosh491 wrote:

Additionally, path resolution isn't a concern in the wasm case for a few reasons (which is why a simple combination of dlopen + dlsym should do the job isn't it ?) 

1) All dynamic libraries are preloaded into MEMFS at known paths during compilation or initialization (e.g., via Emscripten’s --preload-file flag). This means the library’s location is fully deterministic at runtime.

2) No concept of system-level search paths like LD_LIBRARY_PATH in the browser — we can’t rely on an OS-level dynamic loader. Instead, we always load by the full path (e.g., dlopen("/libsymengine.so")), which resolves directly in the virtual MEMFS.

3) Because users control the preload path, and because dlopen in Emscripten expects an exact match in the in-memory filesystem, we don’t need infrastructure for path lookup, search path prioritization, or canonicalization. A simple, direct path-based dlopen is all that’s required.

https://github.com/llvm/llvm-project/pull/133037