dotnet · EgorBo · Dec 6, 2025 · Dec 1, 2025 · Dec 1, 2025 · Dec 1, 2025
diff --git a/docs/design/coreclr/botr/readytorun-format.md b/docs/design/coreclr/botr/readytorun-format.md
@@ -872,7 +872,7 @@ enum ReadyToRunHelper
     READYTORUN_HELPER_MemCpy                    = 0x41,
 
     // Get string handle lazily
-    READYTORUN_HELPER_GetString                 = 0x50,
+    READYTORUN_HELPER_GetString                 = 0x50, // Unused since READYTORUN_MAJOR_VERSION 17.0
 
     // Used by /Tuning for Profile optimizations
     READYTORUN_HELPER_LogMethodEnter            = 0x51, // Unused since READYTORUN_MAJOR_VERSION 10.0

diff --git a/src/coreclr/System.Private.CoreLib/src/System/String.CoreCLR.cs b/src/coreclr/System.Private.CoreLib/src/System/String.CoreCLR.cs
@@ -10,20 +10,6 @@ namespace System
 {
     public partial class String
     {
-        [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "String_StrCns")]
-        private static unsafe partial string* StrCnsInternal(uint rid, IntPtr scopeHandle);
-
-        // implementation of CORINFO_HELP_STRCNS
-        [StackTraceHidden]
-        [DebuggerStepThrough]
-        [DebuggerHidden]
-        internal static unsafe string StrCns(uint rid, IntPtr scopeHandle)
-        {
-            string* ptr = StrCnsInternal(rid, scopeHandle);
-            Debug.Assert(ptr != null);
-            return *ptr;
-        }
-
         [MethodImpl(MethodImplOptions.InternalCall)]
         internal static extern unsafe string FastAllocateString(MethodTable *pMT, nint length);
 

diff --git a/src/coreclr/inc/corinfo.h b/src/coreclr/inc/corinfo.h
@@ -367,8 +367,6 @@ enum CorInfoHelpFunc
     CORINFO_HELP_NEWARR_1_VC,       // optimized 1-D value class arrays
     CORINFO_HELP_NEWARR_1_ALIGN8,   // like VC, but aligns the array start
 
-    CORINFO_HELP_STRCNS,            // create a new string literal
-
     /* Object model */
 
     CORINFO_HELP_INITCLASS,         // Initialize class if not already initialized
@@ -3223,12 +3221,6 @@ class ICorDynamicInfo : public ICorStaticInfo
             CORINFO_CONST_LOOKUP *  pResult
             ) = 0;
 
-    // get slow lazy string literal helper to use (CORINFO_HELP_STRCNS*).
-    // Returns CORINFO_HELP_UNDEF if lazy string literal helper cannot be used.
-    virtual CorInfoHelpFunc getLazyStringLiteralHelper(
-            CORINFO_MODULE_HANDLE   handle
-            ) = 0;
-
     virtual CORINFO_MODULE_HANDLE embedModuleHandle(
             CORINFO_MODULE_HANDLE   handle,
             void                  **ppIndirection = NULL

diff --git a/src/coreclr/inc/icorjitinfoimpl_generated.h b/src/coreclr/inc/icorjitinfoimpl_generated.h
@@ -556,9 +556,6 @@ void getFunctionFixedEntryPoint(
           bool isUnsafeFunctionPointer,
           CORINFO_CONST_LOOKUP* pResult) override;
 
-CorInfoHelpFunc getLazyStringLiteralHelper(
-          CORINFO_MODULE_HANDLE handle) override;
-
 CORINFO_MODULE_HANDLE embedModuleHandle(
           CORINFO_MODULE_HANDLE handle,
           void** ppIndirection) override;

diff --git a/src/coreclr/inc/jiteeversionguid.h b/src/coreclr/inc/jiteeversionguid.h
@@ -37,11 +37,11 @@
 
 #include <minipal/guid.h>
 
-constexpr GUID JITEEVersionIdentifier = { /* 567f89f4-2ddb-4d80-9107-0ce8c30a18ff */
-    0x567f89f4,
-    0x2ddb,
-    0x4d80,
-    {0x91, 0x07, 0x0c, 0xe8, 0xc3, 0x0a, 0x18, 0xff}
+constexpr GUID JITEEVersionIdentifier = { /* 4a42a64a-d034-44d4-8f0d-b7f67b3ea4dc */
+    0x4a42a64a,
+    0xd034,
+    0x44d4,
+    {0x8f, 0x0d, 0xb7, 0xf6, 0x7b, 0x3e, 0xa4, 0xdc}
   };
 
 #endif // JIT_EE_VERSIONING_GUID_H
diff --git a/src/coreclr/inc/jithelpers.h b/src/coreclr/inc/jithelpers.h
@@ -112,8 +112,6 @@
     DYNAMICJITHELPER(CORINFO_HELP_NEWARR_1_VC,          RhpNewVariableSizeObject, METHOD__NIL)
     DYNAMICJITHELPER(CORINFO_HELP_NEWARR_1_ALIGN8,      RhpNewVariableSizeObject, METHOD__NIL)
 
-    DYNAMICJITHELPER(CORINFO_HELP_STRCNS,               NULL,       METHOD__STRING__STRCNS)
-
     // Object model
     DYNAMICJITHELPER(CORINFO_HELP_INITCLASS,           NULL, METHOD__INITHELPERS__INITCLASS)
     DYNAMICJITHELPER(CORINFO_HELP_INITINSTCLASS,       NULL, METHOD__INITHELPERS__INITINSTANTIATEDCLASS)

diff --git a/src/coreclr/inc/readytorun.h b/src/coreclr/inc/readytorun.h
@@ -360,7 +360,7 @@ enum ReadyToRunHelper
     READYTORUN_HELPER_ReversePInvokeExit        = 0x46,
 
     // Get string handle lazily
-    READYTORUN_HELPER_GetString                 = 0x50,
+    READYTORUN_HELPER_GetString                 = 0x50, // No longer supported as of READYTORUN_MAJOR_VERSION 17.0
 
     // Used by /Tuning for Profile optimizations
     READYTORUN_HELPER_LogMethodEnter            = 0x51, // No longer supported as of READYTORUN_MAJOR_VERSION 10.0

diff --git a/src/coreclr/jit/ICorJitInfo_names_generated.h b/src/coreclr/jit/ICorJitInfo_names_generated.h
@@ -137,7 +137,6 @@ DEF_CLR_API(getAddrOfCaptureThreadGlobal)
 DEF_CLR_API(getHelperFtn)
 DEF_CLR_API(getFunctionEntryPoint)
 DEF_CLR_API(getFunctionFixedEntryPoint)
-DEF_CLR_API(getLazyStringLiteralHelper)
 DEF_CLR_API(embedModuleHandle)
 DEF_CLR_API(embedClassHandle)
 DEF_CLR_API(embedMethodHandle)

diff --git a/src/coreclr/jit/ICorJitInfo_wrapper_generated.hpp b/src/coreclr/jit/ICorJitInfo_wrapper_generated.hpp
@@ -1310,15 +1310,6 @@ void WrapICorJitInfo::getFunctionFixedEntryPoint(
     API_LEAVE(getFunctionFixedEntryPoint);
 }
 
-CorInfoHelpFunc WrapICorJitInfo::getLazyStringLiteralHelper(
-          CORINFO_MODULE_HANDLE handle)
-{
-    API_ENTER(getLazyStringLiteralHelper);
-    CorInfoHelpFunc temp = wrapHnd->getLazyStringLiteralHelper(handle);
-    API_LEAVE(getLazyStringLiteralHelper);
-    return temp;
-}
-
 CORINFO_MODULE_HANDLE WrapICorJitInfo::embedModuleHandle(
           CORINFO_MODULE_HANDLE handle,
           void** ppIndirection)

diff --git a/src/coreclr/jit/compiler.hpp b/src/coreclr/jit/compiler.hpp
@@ -4057,7 +4057,7 @@ inline bool Compiler::IsSharedStaticHelper(GenTree* tree)
     bool result1 =
         // More helpers being added to IsSharedStaticHelper (that have similar behaviors but are not true
         // ShareStaticHelpers)
-        helper == CORINFO_HELP_STRCNS || helper == CORINFO_HELP_BOX ||
+        helper == CORINFO_HELP_BOX ||
 
         // helpers being added to IsSharedStaticHelper
         helper == CORINFO_HELP_GETSTATICFIELDADDR_TLS ||

diff --git a/src/coreclr/jit/morph.cpp b/src/coreclr/jit/morph.cpp
@@ -6714,36 +6714,6 @@ GenTree* Compiler::fgMorphConst(GenTree* tree)
         return fgMorphTree(gtNewStringLiteralNode(iat, pValue));
     }
 
-    // TODO-CQ: Do this for compCurBB->isRunRarely(). Doing that currently will
-    // guarantee slow performance for that block. Instead cache the return value
-    // of CORINFO_HELP_STRCNS and go to cache first giving reasonable perf.
-
-    bool useLazyStrCns = false;
-    if (compCurBB->KindIs(BBJ_THROW))
-    {
-        useLazyStrCns = true;
-    }
-    else if (fgGlobalMorph && compCurStmt->GetRootNode()->IsCall())
-    {
-        // Quick check: if the root node of the current statement happens to be a noreturn call.
-        GenTreeCall* call = compCurStmt->GetRootNode()->AsCall();
-        useLazyStrCns     = call->IsNoReturn() || fgIsThrow(call);
-    }
-
-    if (useLazyStrCns)
-    {
-        CorInfoHelpFunc helper = info.compCompHnd->getLazyStringLiteralHelper(tree->AsStrCon()->gtScpHnd);
-        if (helper != CORINFO_HELP_UNDEF)
-        {
-            // For un-important blocks, we want to construct the string lazily
-
-            tree =
-                gtNewHelperCallNode(helper, TYP_REF, gtNewIconNode(RidFromToken(tree->AsStrCon()->gtSconCPX), TYP_INT),
-                                    gtNewIconEmbScpHndNode(tree->AsStrCon()->gtScpHnd));
-            return fgMorphTree(tree);
-        }
-    }
-
     assert(tree->AsStrCon()->gtScpHnd == info.compScopeHnd || !IsUninitialized(tree->AsStrCon()->gtScpHnd));
 
     LPVOID         pValue;

diff --git a/src/coreclr/jit/utils.cpp b/src/coreclr/jit/utils.cpp
@@ -1606,15 +1606,6 @@ void HelperCallProperties::init()
                 nonNullReturn = true;
                 break;
 
-            // Heap Allocation helpers that are also pure
-            case CORINFO_HELP_STRCNS:
-
-                isPure        = true;
-                isAllocator   = true;
-                nonNullReturn = true;
-                exceptions    = ExceptionSetFlags::None; // only can throw OutOfMemory
-                break;
-
             case CORINFO_HELP_BOX_NULLABLE:
                 // Box Nullable is not a 'pure' function
                 // It has a Byref argument that it reads the contents of.

diff --git a/src/coreclr/jit/valuenum.cpp b/src/coreclr/jit/valuenum.cpp
@@ -14291,10 +14291,6 @@ VNFunc Compiler::fgValueNumberJitHelperMethodVNFunc(CorInfoHelpFunc helpFunc)
             vnf = VNF_RuntimeHandleClass;
             break;
 
-        case CORINFO_HELP_STRCNS:
-            vnf = VNF_LazyStrCns;
-            break;
-
         case CORINFO_HELP_CHKCASTCLASS:
         case CORINFO_HELP_CHKCASTCLASS_SPECIAL:
         case CORINFO_HELP_CHKCASTARRAY:

diff --git a/src/coreclr/jit/valuenumfuncs.h b/src/coreclr/jit/valuenumfuncs.h
@@ -165,7 +165,6 @@ ValueNumFuncDef(JitReadyToRunNewLclArr, 3, false, true, false)
 ValueNumFuncDef(Box, 3, false, true, false)
 ValueNumFuncDef(BoxNullable, 3, false, false, false)
 
-ValueNumFuncDef(LazyStrCns, 2, false, true, false)            // Lazy-initialized string literal (helper)
 ValueNumFuncDef(InvariantLoad, 1, false, false, false)        // Args: 0: (VN of) the address.
 ValueNumFuncDef(InvariantNonNullLoad, 1, false, true, false)  // Args: 0: (VN of) the address.
 ValueNumFuncDef(Unbox, 2, false, false, false)

@@ -59,7 +59,6 @@ which is the right helper to use to allocate an object of a given type. */
         CORINFO_HELP_NEWARR_1_VC,       // optimized 1-D value class arrays
         CORINFO_HELP_NEWARR_1_ALIGN8,   // like VC, but aligns the array start
 
-        CORINFO_HELP_STRCNS,            // create a new string literal
         /* Object model */
 
         CORINFO_HELP_INITCLASS,         // Initialize class if not already initialized

@@ -3655,14 +3655,6 @@ public static ReadyToRunHelperId GetReadyToRunHelperFromStaticBaseHelper(CorInfo
         private void getFunctionFixedEntryPoint(CORINFO_METHOD_STRUCT_* ftn, bool isUnsafeFunctionPointer, ref CORINFO_CONST_LOOKUP pResult)
         { throw new NotImplementedException("getFunctionFixedEntryPoint"); }
 
-#pragma warning disable CA1822 // Mark members as static
-        private CorInfoHelpFunc getLazyStringLiteralHelper(CORINFO_MODULE_STRUCT_* handle)
-#pragma warning restore CA1822 // Mark members as static
-        {
-            // TODO: Lazy string literal helper
-            return CorInfoHelpFunc.CORINFO_HELP_UNDEF;
-        }
-
         private CORINFO_MODULE_STRUCT_* embedModuleHandle(CORINFO_MODULE_STRUCT_* handle, ref void* ppIndirection)
         { throw new NotImplementedException("embedModuleHandle"); }