From 91b9ff3e535c6d635a07a2d84696a1e333c38800 Mon Sep 17 00:00:00 2001
From: Vlad Brezae <brezaevlad@gmail.com>
Date: Sat, 27 Jul 2019 17:37:00 +0300
Subject: [PATCH] [interp] Optimize ldelema (#15846)

Makes the opcode 2-3x time faster
---
 mono/mini/interp/interp.c    | 16 ++++++++++++++++
 mono/mini/interp/mintops.def |  1 +
 mono/mini/interp/transform.c | 15 ++++++++++-----
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/mono/mini/interp/interp.c b/mono/mini/interp/interp.c
index 12d37b89da1..c9a1a2ebecc 100644
--- a/mono/mini/interp/interp.c
+++ b/mono/mini/interp/interp.c
@@ -5275,6 +5275,22 @@ interp_exec_method_full (InterpFrame *frame, ThreadContext *context, FrameClause
 			sp [-1].data.i = m_class_get_rank (mono_object_class (sp [-1].data.p));
 			ip++;
 			MINT_IN_BREAK;
+		MINT_IN_CASE(MINT_LDELEMA_FAST) {
+			/* No bounds, one direction */
+			gint32 size = READ32 (ip + 1);
+			gint32 index = sp [-1].data.i;
+
+			MonoArray *ao = (MonoArray*)sp [-2].data.o;
+			if (!ao)
+				THROW_EX (mono_get_exception_null_reference (), ip);
+			if (index >= ao->max_length)
+				THROW_EX (mono_get_exception_index_out_of_range (), ip);
+			sp [-2].data.p = mono_array_addr_with_size_fast (ao, size, index);
+			ip += 3;
+			sp --;
+
+			MINT_IN_BREAK;
+		}
 		MINT_IN_CASE(MINT_LDELEMA)
 		MINT_IN_CASE(MINT_LDELEMA_TC) {
 			gboolean needs_typecheck = *ip == MINT_LDELEMA_TC;
diff --git a/mono/mini/interp/mintops.def b/mono/mini/interp/mintops.def
index 092c6101ac2..0b2e887b03c 100644
--- a/mono/mini/interp/mintops.def
+++ b/mono/mini/interp/mintops.def
@@ -394,6 +394,7 @@ OPDEF(MINT_LDELEM_VT, "ldelem.vt", 3, MintOpInt)
 
 OPDEF(MINT_LDELEMA, "ldelema", 3, MintOpTwoShorts)
 OPDEF(MINT_LDELEMA_TC, "ldelema.tc", 3, MintOpTwoShorts)
+OPDEF(MINT_LDELEMA_FAST, "ldelema.fast", 3, MintOpInt)
 
 OPDEF(MINT_STELEM_I, "stelem.i", 1, MintOpNoArgs)
 OPDEF(MINT_STELEM_I1, "stelem.i1", 1, MintOpNoArgs)
diff --git a/mono/mini/interp/transform.c b/mono/mini/interp/transform.c
index ad5695ca598..87ad5da4241 100644
--- a/mono/mini/interp/transform.c
+++ b/mono/mini/interp/transform.c
@@ -4749,7 +4749,8 @@ generate_code (TransformData *td, MonoMethod *method, MonoMethodHeader *header,
 			SET_SIMPLE_TYPE (td->sp - 1, STACK_TYPE_I4);
 #endif
 			break;
-		case CEE_LDELEMA:
+		case CEE_LDELEMA: {
+			gint32 size;
 			CHECK_STACK (td, 2);
 			ENSURE_I4 (td, 1);
 			token = read32 (td->ip + 1);
@@ -4769,18 +4770,22 @@ generate_code (TransformData *td, MonoMethod *method, MonoMethodHeader *header,
 				mono_class_setup_vtable (klass);
 				CHECK_TYPELOAD (klass);
 				interp_add_ins (td, MINT_LDELEMA_TC);
+				td->last_ins->data [0] = get_data_item_index (td, klass);
+				td->last_ins->data [1] = 2;
 			} else {
-				interp_add_ins (td, MINT_LDELEMA);
+				interp_add_ins (td, MINT_LDELEMA_FAST);
+				mono_class_init_internal (klass);
+				size = mono_class_array_element_size (klass);
+				WRITE32_INS (td->last_ins, 0, &size);
 			}
-			td->last_ins->data [0] = get_data_item_index (td, klass);
-			/* according to spec, ldelema bytecode is only used for 1-dim arrays */
-			td->last_ins->data [1] = 2;
+
 			readonly = FALSE;
 
 			td->ip += 5;
 			--td->sp;
 			SET_SIMPLE_TYPE(td->sp - 1, STACK_TYPE_MP);
 			break;
+		}
 		case CEE_LDELEM_I1:
 			CHECK_STACK (td, 2);
 			ENSURE_I4 (td, 1);
-- 
2.11.4.GIT