[release/9.0-staging][mono][hotreload]Adjust row_size and size_bitfield from the baseline based on the delta sizes

src/libraries/System.Runtime.Loader/tests/ApplyUpdate/System.Reflection.Metadata.ApplyUpdate.Test.IncreaseMetadataRowSize/IncreaseMetadataRowSize.cs

@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+using System;
+namespace System.Reflection.Metadata.ApplyUpdate.Test
+{
+    public static class IncreaseMetadataRowSize
+    {
+        public static void Main(string[] args) { }
+        public static int VeryLooooooooooooooooooooooooooooooooongMethodNameToPushTheStringBlobOver64k_1()
+        {
+            return 0;
+        }
+        public static void VeryLooooooooooooooooooooooooooooooooongMethodNameToPushTheStringBlobOver64k_2(int x2) {}
+        public static void VeryLooooooooooooooooooooooooooooooooongMethodNameToPushTheStringBlobOver64k_3(int x3) {}
+        public static void VeryLooooooooooooooooooooooooooooooooongMethodNameToPushTheStringBlobOver64k_4(int x4) {}
+        public static void VeryLooooooooooooooooooooooooooooooooongMethodNameToPushTheStringBlobOver64k_5(int x5) {}
+    }
+
+}

src/libraries/System.Runtime.Loader/tests/ApplyUpdate/System.Reflection.Metadata.ApplyUpdate.Test.IncreaseMetadataRowSize/System.Reflection.Metadata.ApplyUpdate.Test.IncreaseMetadataRowSize.csproj

@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <RootNamespace>System.Runtime.Loader.Tests</RootNamespace>
+    <TargetFramework>$(NetCoreAppCurrent)</TargetFramework>
+    <TestRuntime>true</TestRuntime>
+    <DeltaScript>deltascript.json</DeltaScript>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="IncreaseMetadataRowSize.cs" />
+  </ItemGroup>
+</Project>

src/libraries/System.Runtime.Loader/tests/ApplyUpdate/System.Reflection.Metadata.ApplyUpdate.Test.IncreaseMetadataRowSize/deltascript.json

@@ -0,0 +1,6 @@
+{
+    "changes": [
+        {"document": "IncreaseMetadataRowSize.cs", "update": "IncreaseMetadataRowSize_v1.cs"},
+    ]
+}
+

src/libraries/System.Runtime.Loader/tests/ApplyUpdateTest.cs

@@ -983,5 +983,25 @@ public static void TestNewMethodThrows()
                 Assert.True(frame1Name == null || frame1Name.Contains("NewMethodThrows.cs"));
             });
         }
+
+        [ConditionalFact(typeof(ApplyUpdateUtil), nameof (ApplyUpdateUtil.IsSupported))]
+        void TestIncreaseMetadataRowSize()
+        {
+            ApplyUpdateUtil.TestCase(static () =>
+            {
+                // Get the custom attribtues from a newly-added type and method
+                // and check that they are the expected ones.
+                var assm = typeof(ApplyUpdate.Test.IncreaseMetadataRowSize).Assembly;
+
+                ApplyUpdateUtil.ApplyUpdate(assm);
+                ApplyUpdateUtil.ClearAllReflectionCaches();
+
+                var r = ApplyUpdate.Test.IncreaseMetadataRowSize.VeryLooooooooooooooooooooooooooooooooongMethodNameToPushTheStringBlobOver64k_1();
+                Assert.Equal(50000, r);
+                MethodInfo mi = typeof(ApplyUpdate.Test.IncreaseMetadataRowSize).GetMethod("VeryLooooooooooooooooooooooooooooooooongMethodNameToPushTheStringBlobOver64k_800");
+                ParameterInfo[] pars = mi.GetParameters();
+                Assert.Equal("x800", pars[0].Name);
+            });
+        }
     }       
 }

src/libraries/System.Runtime.Loader/tests/System.Runtime.Loader.Tests.csproj

@@ -67,6 +67,7 @@
     <ProjectReference Include="ApplyUpdate\System.Reflection.Metadata.ApplyUpdate.Test.GenericAddStaticField\System.Reflection.Metadata.ApplyUpdate.Test.GenericAddStaticField.csproj" />
     <ProjectReference Include="ApplyUpdate\System.Reflection.Metadata.ApplyUpdate.Test.GenericAddInstanceField\System.Reflection.Metadata.ApplyUpdate.Test.GenericAddInstanceField.csproj" />
     <ProjectReference Include="ApplyUpdate\System.Reflection.Metadata.ApplyUpdate.Test.NewMethodThrows\System.Reflection.Metadata.ApplyUpdate.Test.NewMethodThrows.csproj" />
+    <ProjectReference Include="ApplyUpdate\System.Reflection.Metadata.ApplyUpdate.Test.IncreaseMetadataRowSize\System.Reflection.Metadata.ApplyUpdate.Test.IncreaseMetadataRowSize.csproj" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetOS)' == 'browser'">
     <WasmFilesToIncludeFromPublishDir Include="$(AssemblyName).dll" />

src/mono/mono/component/hot_reload.c

@@ -924,9 +924,7 @@ delta_info_initialize_mutants (const MonoImage *base, const BaselineInfo *base_i
 		g_assert (prev_table != NULL);
 
 		MonoTableInfo *tbl = &delta->mutants [i];
-		if (prev_table->rows_ == 0) {
-			/* table was empty in the baseline and it was empty in the prior generation, but now we have some rows. Use the format of the mutant table. */
-			g_assert (prev_table->row_size == 0);
+		if (delta->delta_image->tables [i].row_size != 0 || prev_table->rows_ == 0) {
 			tbl->row_size = delta->delta_image->tables [i].row_size;
 			tbl->size_bitfield = delta->delta_image->tables [i].size_bitfield;
 		} else {
@@ -940,8 +938,60 @@ delta_info_initialize_mutants (const MonoImage *base, const BaselineInfo *base_i
 		tbl->base = mono_mempool_alloc (delta->pool, tbl->row_size * rows);
 		g_assert (table_info_get_rows (prev_table) == count->prev_gen_rows);
 
-		/* copy the old rows  and zero out the new ones */
-		memcpy ((char*)tbl->base, prev_table->base, count->prev_gen_rows * tbl->row_size);
+		/* copy the old rows and zero out the new ones */
+		/* we need to copy following the new format (uncompressed one)*/
+		for (guint32 j = 0 ; j < count->prev_gen_rows; j++)
+		{
+			guint32 src_offset = 0, dst_offset = 0;
+			guint32 dst_bitfield = tbl->size_bitfield;
+			guint32 src_bitfield = prev_table->size_bitfield;
+			const char *src_base = (char*)prev_table->base + j *  prev_table->row_size;
+			char *dst_base = (char*)tbl->base + j * tbl->row_size;
+			for (guint col = 0; col < mono_metadata_table_count (dst_bitfield); ++col) {
+				guint32 dst_col_size = mono_metadata_table_size (dst_bitfield, col);
+				guint32 src_col_size = mono_metadata_table_size (src_bitfield, col);
+				{
+					const char *src = src_base + src_offset;
+					char *dst = dst_base + dst_offset;
+
+					/* copy src to dst, via a temporary to adjust for size differences */
+					/* FIXME: unaligned access, endianness */
+					guint32 tmp;
+
+					switch (src_col_size) {
+					case 1:
+						tmp = *(guint8*)src;
+						break;
+					case 2:
+						tmp = *(guint16*)src;
+						break;
+					case 4:
+						tmp = *(guint32*)src;
+						break;
+					default:
+						g_assert_not_reached ();
+					}
+
+					/* FIXME: unaligned access, endianness */
+					switch (dst_col_size) {
+					case 1:
+						*(guint8*)dst = (guint8)tmp;
+						break;
+					case 2:
+						*(guint16*)dst = (guint16)tmp;
+						break;
+					case 4:
+						*(guint32*)dst = tmp;
+						break;
+					default:
+						g_assert_not_reached ();
+					}
+				}
+				src_offset += src_col_size;
+				dst_offset += dst_col_size;
+			}
+			g_assert (dst_offset == tbl->row_size);
+		}
 		memset (((char*)tbl->base) + count->prev_gen_rows * tbl->row_size, 0, count->inserted_rows * tbl->row_size);
 	}
 }
@@ -1386,8 +1436,8 @@ delta_info_mutate_row (MonoImage *image_dmeta, DeltaInfo *cur_delta, guint32 log
 
 	/* The complication here is that we want the mutant table to look like the table in
 	 * the baseline image with respect to column widths, but the delta tables are generally coming in
-	 * uncompressed (4-byte columns).  So we have to copy one column at a time and adjust the
-	 * widths as we go.
+	 * uncompressed (4-byte columns).  And we have already adjusted the baseline image column widths 
+	 * so we can use memcpy here.
 	 */
 
 	guint32 dst_bitfield = cur_delta->mutants [token_table].size_bitfield;
@@ -1401,41 +1451,10 @@ delta_info_mutate_row (MonoImage *image_dmeta, DeltaInfo *cur_delta, guint32 log
 		guint32 dst_col_size = mono_metadata_table_size (dst_bitfield, col);
 		guint32 src_col_size = mono_metadata_table_size (src_bitfield, col);
 		if ((m_SuppressedDeltaColumns [token_table] & (1 << col)) == 0) {
+			g_assert(src_col_size <= dst_col_size);
 			const char *src = src_base + src_offset;
 			char *dst = dst_base + dst_offset;
-
-			/* copy src to dst, via a temporary to adjust for size differences */
-			/* FIXME: unaligned access, endianness */
-			guint32 tmp;
-
-			switch (src_col_size) {
-			case 1:
-				tmp = *(guint8*)src;
-				break;
-			case 2:
-				tmp = *(guint16*)src;
-				break;
-			case 4:
-				tmp = *(guint32*)src;
-				break;
-			default:
-				g_assert_not_reached ();
-			}
-
-			/* FIXME: unaligned access, endianness */
-			switch (dst_col_size) {
-			case 1:
-				*(guint8*)dst = (guint8)tmp;
-				break;
-			case 2:
-				*(guint16*)dst = (guint16)tmp;
-				break;
-			case 4:
-				*(guint32*)dst = tmp;
-				break;
-			default:
-				g_assert_not_reached ();
-			}
+			memcpy(dst, src, src_col_size);
 		}
 		src_offset += src_col_size;
 		dst_offset += dst_col_size;