[mono] Fix invoking string ctors on wasm in AOT mode. (#52505)

* [mono] Avoid passing a dummy string to string ctors from runtime invokes, pass NULL instead.

The call will go to a wrapper method which will ignore the 'this' argument anyway.

* [mono] Fix invoking string ctors on wasm in AOT mode.

diff --git a/src/mono/mono/metadata/marshal-ilgen.c b/src/mono/mono/metadata/marshal-ilgen.c
index a253af0..151e05a 100644 (file)
--- a/src/mono/mono/metadata/marshal-ilgen.c
+++ b/src/mono/mono/metadata/marshal-ilgen.c
@@ -1507,30 +1507,11 @@ emit_invoke_call (MonoMethodBuilder *mb, MonoMethod *method,
                                  int loc_res,
                                  gboolean virtual_, gboolean need_direct_wrapper)
 {
-       static MonoString *string_dummy = NULL;
        int i;
        int *tmp_nullable_locals;
        gboolean void_ret = FALSE;
        gboolean string_ctor = method && method->string_ctor;
 
-       /* to make it work with our special string constructors */
-       if (!string_dummy) {
-               ERROR_DECL (error);
-
-               // FIXME Allow for static construction of MonoString.
-
-               SETUP_ICALL_FUNCTION;
-               SETUP_ICALL_FRAME;
-
-               MONO_GC_REGISTER_ROOT_SINGLE (string_dummy, MONO_ROOT_SOURCE_MARSHAL, NULL, "Marshal Dummy String");
-
-               MonoStringHandle string_dummy_handle = mono_string_new_utf8_len ("dummy", 5, error);
-               string_dummy = MONO_HANDLE_RAW (string_dummy_handle);
-               mono_error_assert_ok (error);
-
-               CLEAR_ICALL_FRAME;
-       }
-
        if (virtual_) {
                g_assert (sig->hasthis);
                g_assert (method->flags & METHOD_ATTRIBUTE_VIRTUAL);
@@ -1538,12 +1519,9 @@ emit_invoke_call (MonoMethodBuilder *mb, MonoMethod *method,
 
        if (sig->hasthis) {
                if (string_ctor) {
-                       if (mono_gc_is_moving ()) {
-                               mono_mb_emit_ptr (mb, &string_dummy);
-                               mono_mb_emit_byte (mb, CEE_LDIND_REF);
-                       } else {
-                               mono_mb_emit_ptr (mb, string_dummy);
-                       }
+                       /* This will call the code emitted by mono_marshal_get_native_wrapper () which ignores it */
+                       mono_mb_emit_icon (mb, 0);
+                       mono_mb_emit_byte (mb, CEE_CONV_I);
                } else {
                        mono_mb_emit_ldarg (mb, 0);
                }

diff --git a/src/mono/mono/mini/aot-compiler.c b/src/mono/mono/mini/aot-compiler.c
index 4cc99ae..6bb97b2 100644 (file)
--- a/src/mono/mono/mini/aot-compiler.c
+++ b/src/mono/mono/mini/aot-compiler.c
@@ -4731,6 +4731,20 @@ add_wrappers (MonoAotCompile *acfg)
                /* FIXME: locking - this is "safe" as full-AOT threads don't mutate the icall data */
                for (int i = 0; i < MONO_JIT_ICALL_count; ++i)
                        add_jit_icall_wrapper (acfg, mono_find_jit_icall_info ((MonoJitICallId)i));
+
+               if (acfg->aot_opts.llvm_only) {
+                       /* String ctors are called directly on llvmonly */
+                       for (int i = 0; i < rows; ++i) {
+                               ERROR_DECL (error);
+
+                               token = MONO_TOKEN_METHOD_DEF | (i + 1);
+                               method = mono_get_method_checked (acfg->image, token, NULL, NULL, error);
+                               if (method && method->string_ctor) {
+                                       MonoMethod *w = get_runtime_invoke (acfg, method, FALSE);
+                                       add_method (acfg, w);
+                               }
+                       }
+               }
        }
 
        /* 

diff --git a/src/mono/mono/mini/mini-runtime.c b/src/mono/mono/mini/mini-runtime.c
index 6c2e6c4..e450f92 100644 (file)
--- a/src/mono/mono/mini/mini-runtime.c
+++ b/src/mono/mono/mini/mini-runtime.c
@@ -2921,10 +2921,7 @@ create_runtime_invoke_info (MonoMethod *method, gpointer compiled_method, gboole
        info = g_new0 (RuntimeInvokeInfo, 1);
        info->compiled_method = compiled_method;
        info->use_interp = use_interp;
-       if (mono_llvm_only && method->string_ctor)
-               info->sig = mono_marshal_get_string_ctor_signature (method);
-       else
-               info->sig = mono_method_signature_internal (method);
+       info->sig = mono_method_signature_internal (method);
 
        invoke = mono_marshal_get_runtime_invoke (method, FALSE);
        (void)invoke;
@@ -3016,7 +3013,13 @@ create_runtime_invoke_info (MonoMethod *method, gpointer compiled_method, gboole
        }
 
        if (!info->dyn_call_info) {
-               if (mono_llvm_only) {
+               /*
+                * Can't use the normal llvmonly code for string ctors since the gsharedvt out wrapper passes
+                * an extra arg, which the string ctor methods don't have, which causes signature mismatches
+                * on wasm. Instead, call string ctors normally using a direct runtime invoke wrapper
+                * which is AOTed for each ctor.
+                */
+               if (mono_llvm_only && !method->string_ctor) {
 #ifndef MONO_ARCH_GSHAREDVT_SUPPORTED
                        g_assert_not_reached ();
 #endif
@@ -3331,7 +3334,7 @@ mono_jit_runtime_invoke (MonoMethod *method, void *obj, void **params, MonoObjec
        if (info->use_interp) {
                result = mini_get_interp_callbacks ()->runtime_invoke (method, obj, params, exc, error);
                return_val_if_nok (error, NULL);
-       } else if (mono_llvm_only) {
+       } else if (mono_llvm_only && !method->string_ctor) {
                result = mono_llvmonly_runtime_invoke (method, info, obj, params, exc, error);
                if (!is_ok (error))
                        return NULL;