Link WebAssembly runtime (#5141)

* Changes to hook up the portable runtime and bootstrapper. Includes implementing allocation using RhpNewFast as well as some floating point codegen fixes required to make the new code compile.
Removes usage of buggy dladdr API in WebAssembly, fixes order of conditional branch expressions, which fixes printing when C# optimizations are enabled, adds debug and release flags to emcc, updates WebAssembly documentation to reflect the new build flavor and linking steps. Adds thunks for RuntimeExport methods to fix linker errors for missing runtime exports.

1 files changed, 24 insertions, 2 deletions

diff --git a/src/Native/Runtime/unix/PalRedhawkUnix.cpp b/src/Native/Runtime/unix/PalRedhawkUnix.cpp
index 0b91e07a5..942dad75f 100644
--- a/src/Native/Runtime/unix/PalRedhawkUnix.cpp
+++ b/src/Native/Runtime/unix/PalRedhawkUnix.cpp
@@ -631,6 +631,10 @@ typedef UInt32(__stdcall *BackgroundCallback)(_In_opt_ void* pCallbackContext);
 
 REDHAWK_PALEXPORT bool REDHAWK_PALAPI PalStartBackgroundWork(_In_ BackgroundCallback callback, _In_opt_ void* pCallbackContext, UInt32_BOOL highPriority)
 {
+#ifdef _WASM_
+    // No threads, so we can't start one
+    ASSERT(false);
+#endif // _WASM_
     pthread_attr_t attrs;
 
     int st = pthread_attr_init(&attrs);
@@ -671,7 +675,12 @@ REDHAWK_PALEXPORT bool REDHAWK_PALAPI PalStartBackgroundGCThread(_In_ Background
 
 REDHAWK_PALEXPORT bool REDHAWK_PALAPI PalStartFinalizerThread(_In_ BackgroundCallback callback, _In_opt_ void* pCallbackContext)
 {
+#ifdef _WASM_
+    // WASMTODO: No threads so we can't start the finalizer thread
+    return true;
+#else // _WASM_
     return PalStartBackgroundWork(callback, pCallbackContext, UInt32_TRUE);
+#endif // _WASM_
 }
 
 // Returns a 64-bit tick count with a millisecond resolution. It tries its best
@@ -729,12 +738,17 @@ REDHAWK_PALEXPORT UInt32 REDHAWK_PALAPI PalGetTickCount()
 REDHAWK_PALEXPORT HANDLE REDHAWK_PALAPI PalGetModuleHandleFromPointer(_In_ void* pointer)
 {
     HANDLE moduleHandle = NULL;
+
+    // Emscripten's implementation of dladdr corrupts memory,
+    // but always returns 0 for the module handle, so just skip the call
+#if !defined(_WASM_)
     Dl_info info;
     int st = dladdr(pointer, &info);
     if (st != 0)
     {
         moduleHandle = info.dli_fbase;
     }
+#endif //!defined(_WASM_)
 
     return moduleHandle;
 }
@@ -802,8 +816,9 @@ bool QueryCacheSize()
     }
 
 #elif defined(_WASM_)
-    // Processor cache size not available on WebAssembly
-    success = false;
+    // Processor cache size not available on WebAssembly, but we can't start up without it, so pick the same default as the GC does
+    success = true;
+    g_cbLargestOnDieCache = 256 * 1024;
 #else
 #error Do not know how to get cache size on this platform
 #endif // __linux__
@@ -1216,6 +1231,12 @@ REDHAWK_PALEXPORT bool PalGetMaximumStackBounds(_Out_ void** ppStackLowOut, _Out
 //
 REDHAWK_PALEXPORT Int32 PalGetModuleFileName(_Out_ const TCHAR** pModuleNameOut, HANDLE moduleBase)
 {
+#if defined(_WASM_)
+    // Emscripten's implementation of dladdr corrupts memory and doesn't have the real name, so make up a name instead
+    const TCHAR* wasmModuleName = "WebAssemblyModule";
+    *pModuleNameOut = wasmModuleName;
+    return strlen(wasmModuleName);
+#else // _WASM_
     Dl_info dl;
     if (dladdr(moduleBase, &dl) == 0)
     {
@@ -1225,6 +1246,7 @@ REDHAWK_PALEXPORT Int32 PalGetModuleFileName(_Out_ const TCHAR** pModuleNameOut,
 
     *pModuleNameOut = dl.dli_fname;
     return strlen(dl.dli_fname);
+#endif // defined(_WASM_)
 }
 
 GCSystemInfo g_SystemInfo;