Restore symbol-free decoding for CORINFO_HELP_NEW helpers

docs/design/datacontracts/AuxiliarySymbols.md

@@ -1,7 +1,8 @@
 # Contract AuxiliarySymbols
 
-This contract provides name resolution for helper functions whose executing code
-resides at dynamically-determined addresses.
+This contract provides name resolution for helper functions. It may include other functions in the future but at minimum it has functions:
+* whose executing code resides at dynamically-determined addresses or
+* that are native helpers used to implement new.
 
 ## APIs of contract
 
@@ -20,7 +21,7 @@ bool TryGetAuxiliarySymbolName(TargetPointer ip, out string symbolName);
 | Data Descriptor | Field | Type | Meaning |
 | --- | --- | --- | --- |
 | `AuxiliarySymbolInfo` | *(type size)* | `uint32` | Size in bytes of each entry in the auxiliary symbol array |
-| `AuxiliarySymbolInfo` | `Address` | `CodePointer` | Code pointer to the dynamically-located helper function |
+| `AuxiliarySymbolInfo` | `Address` | `CodePointer` | Code pointer to the helper function |
 | `AuxiliarySymbolInfo` | `Name` | `pointer` | Pointer to a null-terminated char string with the helper name |
 
 ### Global variables used

docs/design/datacontracts/data-descriptor-meanings.json

@@ -22,7 +22,7 @@
     "AsyncMethodData.Signature": "The async variant's signature (see `Signature`)",
     "AsyncMethodData.Size": "Size of the async method data, added when HasAsyncMethodData flag is set",
     "AsyncResumeInfo.DiagnosticIP": "Native IP into the resumed method used for diagnostics (may be null)",
-    "AuxiliarySymbolInfo.Address": "Code pointer to the dynamically-located helper function",
+    "AuxiliarySymbolInfo.Address": "Code pointer to the helper function",
     "AuxiliarySymbolInfo.Name": "Pointer to a null-terminated char string with the helper name",
     "AuxiliarySymbolInfo.Size": "Size in bytes of each entry in the auxiliary symbol array",
     "Bucket.Keys": "Array of keys of `HashMapSlotsPerBucket` length",

src/coreclr/vm/jitinterface.h

@@ -1008,7 +1008,7 @@ struct VMAUXILIARYSYMBOLDEF
     PTR_CSTR name;
 };
 
-#define MAX_AUXILIARY_SYMBOLS 7
+#define MAX_AUXILIARY_SYMBOLS 17
 
 #if defined(DACCESS_COMPILE)
 

src/coreclr/vm/jitinterfacegen.cpp

@@ -11,6 +11,24 @@
 #include "ecall.h"
 #include "writebarriermanager.h"
 
+static void SetJitHelperAuxiliarySymbol(CorInfoHelpFunc ftnNum, const char* name)
+{
+    LIMITED_METHOD_CONTRACT;
+
+    VMHELPDEF const& helperDef = hlpFuncTable[ftnNum];
+    PCODE pfnHelper = helperDef.pfnHelper;
+    DynamicCorInfoHelpFunc dynamicFtnNum;
+    if (helperDef.IsDynamicHelper(&dynamicFtnNum))
+    {
+        pfnHelper = hlpDynamicFuncTable[dynamicFtnNum].pfnHelper;
+    }
+
+    if (pfnHelper != (PCODE)NULL)
+    {
+        SetAuxiliarySymbol((void*)pfnHelper, name);
+    }
+}
+
 void InitJITAllocationHelpers()
 {
     STANDARD_VM_CONTRACT;
@@ -57,4 +75,18 @@ void InitJITAllocationHelpers()
 #endif
         }
     }
+
+// Debugger depends on new helper names starting with CORINFO_HELP_NEW
+#define SET_NEW_HELPER_AUXILIARY_SYMBOL(code) SetJitHelperAuxiliarySymbol(code, #code);
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWFAST)
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWFAST_MAYBEFROZEN)
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWSFAST)
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWSFAST_ALIGN8)
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWSFAST_ALIGN8_VC)
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWARR_1_DIRECT)
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWARR_1_MAYBEFROZEN)
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWARR_1_PTR)
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWARR_1_VC)
+    SET_NEW_HELPER_AUXILIARY_SYMBOL(CORINFO_HELP_NEWARR_1_ALIGN8)
+#undef SET_NEW_HELPER_AUXILIARY_SYMBOL
 }

src/native/managed/cdac/tests/DumpTests/AuxiliarySymbolsDumpTests.cs

@@ -0,0 +1,65 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using Microsoft.Diagnostics.DataContractReader.Contracts;
+using Microsoft.Diagnostics.DataContractReader.TestInfrastructure;
+using Xunit;
+
+namespace Microsoft.Diagnostics.DataContractReader.DumpTests;
+
+public class AuxiliarySymbolsDumpTests : DumpTestBase
+{
+    protected override string DebuggeeName => "BasicThreads";
+    protected override string DumpType => "full";
+
+    [ConditionalTheory]
+    [MemberData(nameof(TestConfigurations))]
+    [SkipOnVersion("net10.0", "Allocation helpers are not included in the .NET 10 auxiliary symbol table")]
+    public void JitHelpersAreReachableByAddress(TestConfiguration config)
+    {
+        InitializeDumpTest(config);
+
+        HashSet<string> expectedHelpers =
+        [
+            "CORINFO_HELP_NEWFAST",
+            "CORINFO_HELP_NEWFAST_MAYBEFROZEN",
+            "CORINFO_HELP_NEWSFAST",
+            "CORINFO_HELP_NEWSFAST_ALIGN8",
+            "CORINFO_HELP_NEWSFAST_ALIGN8_VC",
+            "CORINFO_HELP_NEWARR_1_DIRECT",
+            "CORINFO_HELP_NEWARR_1_MAYBEFROZEN",
+            "CORINFO_HELP_NEWARR_1_PTR",
+            "CORINFO_HELP_NEWARR_1_VC",
+            "CORINFO_HELP_NEWARR_1_ALIGN8",
+        ];
+        Dictionary<TargetCodePointer, string> helpersByAddress = [];
+
+        TargetPointer table = Target.ReadGlobalPointer(Constants.Globals.AuxiliarySymbols);
+        uint count = Target.Read<uint>(Target.ReadGlobalPointer(Constants.Globals.AuxiliarySymbolCount));
+        Target.TypeInfo typeInfo = Target.GetTypeInfo(DataType.AuxiliarySymbolInfo);
+        uint entrySize = typeInfo.Size!.Value;
+        int addressOffset = typeInfo.Fields["Address"].Offset;
+        int nameOffset = typeInfo.Fields["Name"].Offset;
+
+        for (uint i = 0; i < count; i++)
+        {
+            TargetPointer entry = table + ((ulong)i * entrySize);
+            TargetPointer namePointer = Target.ReadPointer(entry + (ulong)nameOffset);
+            string name = Target.ReadUtf8String(namePointer);
+            if (expectedHelpers.Remove(name))
+            {
+                TargetCodePointer address = Target.ReadCodePointer(entry + (ulong)addressOffset);
+                Assert.NotEqual(TargetCodePointer.Null, address);
+                helpersByAddress.TryAdd(address, name);
+            }
+        }
+
+        Assert.Empty(expectedHelpers);
+        foreach ((TargetCodePointer address, string expectedName) in helpersByAddress)
+        {
+            Assert.True(Target.Contracts.AuxiliarySymbols.TryGetAuxiliarySymbolName(address.AsTargetPointer, out string? name));
+            Assert.Equal(expectedName, name);
+        }
+    }
+}