Add a loader state for HiPE code loading

Just like the BEAM loader state (as returned by
erlang:prepare_loading/2), the HiPE loader state is contained in a magic
binary.

Eventually, we will separate HiPE loading into a prepare and a finalise
phase, like the BEAM loader, where the prepare phase will be implemented
by hipe_unified_loader and the finalise phase be implemented in C by
hipe_load.c and beam_load.c, making prepare side-effect free and
finalise atomic. The finalise phase will be exposed through the
erlang:finish_loading/1 API, just like the BEAM loader, as this will
allow HiPE and BEAM modules to be mixed in the same atomic "commit".

The usage of a loader state makes it easier to keep track of all
resources allocated during loading, and will not only make it easy to
prevent leaks when hipe_unified_loader crashes, but also paves the way
for proper, leak-free, unloading of HiPE modules.

1 files changed, 101 insertions, 0 deletions

diff --git a/erts/emulator/hipe/hipe_load.c b/erts/emulator/hipe/hipe_load.c
new file mode 100644
index 0000000000..5bce3f1aee
--- /dev/null
+++ b/erts/emulator/hipe/hipe_load.c
@@ -0,0 +1,101 @@
+/*
+ * %CopyrightBegin%
+
+ *
+ * Copyright Ericsson AB 2016. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * %CopyrightEnd%
+ */
+/*
+ * hipe_load.c
+ *
+ * HiPE atomic code loader
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#include "sys.h"
+#include "global.h"
+#include "erl_binary.h"
+#include "hipe_load.h"
+
+/*
+ * This destructor function can safely be called multiple times.
+ */
+static void
+hipe_loader_state_dtor(Binary* magic)
+{
+    HipeLoaderState* stp = ERTS_MAGIC_BIN_DATA(magic);
+    if (stp->module == NIL) return;
+
+    erts_fprintf(stderr, "Destroying HiPE loader state for module %T\n",
+		 stp->module);
+
+    // TODO: Needs to be freed separately. We'd like have a unified executable
+    // code allocator, so postpone this for now.
+    /* if (stp->text_segment) */
+    /* 	erts_free(ERTS_ALC_T_HIPE, stp->text_segment); */
+    stp->text_segment = NULL;
+    stp->text_segment_size = 0;
+
+    if (stp->data_segment)
+	erts_free(ERTS_ALC_T_HIPE, stp->data_segment);
+    stp->data_segment = NULL;
+    stp->data_segment_size = 0;
+
+    stp->module = NIL;
+}
+
+Binary *hipe_alloc_loader_state(Eterm module)
+{
+    HipeLoaderState *stp;
+    Binary *magic;
+
+    if (is_not_atom(module)) return NULL;
+
+    erts_fprintf(stderr, "Creating HiPE loader state for module %T\n", module);
+
+    magic = erts_create_magic_binary(sizeof(HipeLoaderState),
+				     hipe_loader_state_dtor);
+    erts_refc_inc(&magic->refc, 1);
+    stp = ERTS_MAGIC_BIN_DATA(magic);
+
+    stp->module = module;
+    stp->text_segment = NULL;
+    stp->text_segment_size = 0;
+    stp->data_segment = NULL;
+    stp->data_segment_size = 0;
+
+    return magic;
+}
+
+void hipe_free_loader_state(Binary *magic)
+{
+    if (ERTS_MAGIC_BIN_DESTRUCTOR(magic) != hipe_loader_state_dtor)
+	return;
+
+    /* Why does BEAM do a refc_dec here? What is holding that reference? */
+    hipe_loader_state_dtor(magic);
+}
+
+HipeLoaderState *
+hipe_get_loader_state(Binary *magic)
+{
+    if (ERTS_MAGIC_BIN_DESTRUCTOR(magic) != hipe_loader_state_dtor)
+	return NULL;
+
+    return (HipeLoaderState*) ERTS_MAGIC_BIN_DATA(magic);
+}