From 15c6637c8691a189aaaf87a713a9acd3d1587c23 Mon Sep 17 00:00:00 2001
From: Vlad Brezae <brezaevlad@gmail.com>
Date: Wed, 12 Aug 2020 13:53:09 +0300
Subject: [PATCH] [interp] Intrinsify IndexOfOrLessThan

Speeds up json deserialization by 5-10%
---
 .../src/System/Text/Json/Reader/JsonReaderHelper.cs  |  1 +
 src/mono/mono/mini/interp/interp-intrins.c           | 12 ++++++++++++
 src/mono/mono/mini/interp/interp-intrins.h           |  3 +++
 src/mono/mono/mini/interp/interp.c                   |  6 ++++++
 src/mono/mono/mini/interp/mintops.def                |  1 +
 src/mono/mono/mini/interp/transform.c                |  5 +++++
 6 files changed, 28 insertions(+)

diff --git a/src/libraries/System.Text.Json/src/System/Text/Json/Reader/JsonReaderHelper.cs b/src/libraries/System.Text.Json/src/System/Text/Json/Reader/JsonReaderHelper.cs
index dbea5c0fea0c10..94f1973d1f100c 100644
--- a/src/libraries/System.Text.Json/src/System/Text/Json/Reader/JsonReaderHelper.cs
+++ b/src/libraries/System.Text.Json/src/System/Text/Json/Reader/JsonReaderHelper.cs
@@ -75,6 +75,7 @@ ref MemoryMarshal.GetReference(span),
                     span.Length);
         }
 
+        // Intrinsified in mono interpreter
         private static unsafe int IndexOfOrLessThan(ref byte searchSpace, byte value0, byte value1, byte lessThan, int length)
         {
             Debug.Assert(length >= 0);
diff --git a/src/mono/mono/mini/interp/interp-intrins.c b/src/mono/mono/mini/interp/interp-intrins.c
index b4093225dd288a..1cfb7e660a38d8 100644
--- a/src/mono/mono/mini/interp/interp-intrins.c
+++ b/src/mono/mono/mini/interp/interp-intrins.c
@@ -138,3 +138,15 @@ interp_intrins_widen_ascii_to_utf16 (guint8 *pAsciiBuffer, mono_unichar2 *pUtf16
 	}
 	return currentOffset;
 }
+
+int
+interp_intrins_json_index_of_lt (guint8 *searchSpace, guint8 value0, guint8 value1, guint8 lessThan, gint32 length)
+{
+	for (int i = 0; i < length; i++) {
+		guint8 value = searchSpace [i];
+		if (value0 == value || value1 == value || lessThan > value)
+			return i;
+	}
+
+	return -1;
+}
diff --git a/src/mono/mono/mini/interp/interp-intrins.h b/src/mono/mono/mini/interp/interp-intrins.h
index 2be852f3315208..35e4dedb66ba59 100644
--- a/src/mono/mono/mini/interp/interp-intrins.h
+++ b/src/mono/mono/mini/interp/interp-intrins.h
@@ -24,4 +24,7 @@ interp_intrins_u32_to_decstr (guint32 value, MonoArray *cache, MonoVTable *vtabl
 mono_u
 interp_intrins_widen_ascii_to_utf16 (guint8 *pAsciiBuffer, mono_unichar2 *pUtf16Buffer, mono_u elementCount);
 
+int
+interp_intrins_json_index_of_lt (guint8 *searchSpace, guint8 value0, guint8 value1, guint8 lessThan, gint32 length);
+
 #endif /* __MONO_MINI_INTERP_INTRINSICS_H__ */
diff --git a/src/mono/mono/mini/interp/interp.c b/src/mono/mono/mini/interp/interp.c
index 53d20e1997c8d7..6ba5dff0dcfa4f 100644
--- a/src/mono/mono/mini/interp/interp.c
+++ b/src/mono/mono/mini/interp/interp.c
@@ -5355,6 +5355,12 @@ interp_exec_method (InterpFrame *frame, ThreadContext *context, FrameClauseArgs
 			ip++;
 			MINT_IN_BREAK;
 		}
+		MINT_IN_CASE(MINT_INTRINS_JSON_INDEX_OF_LT) {
+			sp -= 4;
+			sp [-1].data.i = interp_intrins_json_index_of_lt ((guint8*)sp [-1].data.p, (guint8)sp [0].data.i, (guint8)sp [1].data.i, (guint8)sp [2].data.i, sp [3].data.i);
+			ip++;
+			MINT_IN_BREAK;
+		}
 		MINT_IN_CASE(MINT_INTRINS_UNSAFE_BYTE_OFFSET) {
 			sp -= 2;
 			sp [0].data.nati = (guint8*)sp [1].data.p - (guint8*)sp [0].data.p;
diff --git a/src/mono/mono/mini/interp/mintops.def b/src/mono/mono/mini/interp/mintops.def
index 6e4d90fab787fa..d4731aedcda6ad 100644
--- a/src/mono/mono/mini/interp/mintops.def
+++ b/src/mono/mono/mini/interp/mintops.def
@@ -800,3 +800,4 @@ OPDEF(MINT_INTRINS_ORDINAL_IGNORE_CASE_ASCII, "intrins_ordinal_ignore_case_ascii
 OPDEF(MINT_INTRINS_64ORDINAL_IGNORE_CASE_ASCII, "intrins_64ordinal_ignore_case_ascii", 1, Pop2, Push1, MintOpNoArgs)
 OPDEF(MINT_INTRINS_U32_TO_DECSTR, "intrins_u32_to_decstr", 3, Pop1, Push1, MintOpNoArgs)
 OPDEF(MINT_INTRINS_WIDEN_ASCII_TO_UTF16, "intrins_widen_ascii_to_utf16", 1, Pop3, Push1, MintOpNoArgs)
+OPDEF(MINT_INTRINS_JSON_INDEX_OF_LT, "intrins_json_index_of_lt", 1, Pop5, Push1, MintOpNoArgs)
diff --git a/src/mono/mono/mini/interp/transform.c b/src/mono/mono/mini/interp/transform.c
index a0fd6c0b068989..3e2564ee628f80 100644
--- a/src/mono/mono/mini/interp/transform.c
+++ b/src/mono/mono/mini/interp/transform.c
@@ -1895,6 +1895,11 @@ interp_handle_intrinsics (TransformData *td, MonoMethod *target_method, MonoClas
 			!strncmp ("System.Runtime.Intrinsics", klass_name_space, 25) &&
 			!strcmp (tm, "get_IsSupported")) {
 		*op = MINT_LDC_I4_0;
+	} else if (!strcmp (m_class_get_image (target_method->klass)->assembly_name, "System.Text.Json") &&
+			!strcmp (klass_name_space, "System.Text.Json") &&
+			!strcmp (klass_name, "JsonReaderHelper")) {
+		if (!strcmp (tm, "IndexOfOrLessThan"))
+			*op = MINT_INTRINS_JSON_INDEX_OF_LT;
 	}
 #endif