Implement portable tailcall helpers

src/coreclr/src/System.Private.CoreLib/src/System/Runtime/CompilerServices/RuntimeHelpers.CoreCLR.cs

@@ -286,8 +286,16 @@ public static IntPtr AllocateTypeAssociatedMemory(Type type, int size)
 
         [DllImport(RuntimeHelpers.QCall)]
         private static extern IntPtr AllocateTypeAssociatedMemoryInternal(QCallTypeHandle type, uint size);
-    }
 
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        private static extern IntPtr AllocTailCallArgBuffer(int size, IntPtr gcDesc);
+
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        private static extern void FreeTailCallArgBuffer();
+
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        private static unsafe extern TailCallTls* GetTailCallInfo(IntPtr retAddrSlot, IntPtr* retAddr);
+    }
     // Helper class to assist with unsafe pinning of arbitrary objects.
     // It's used by VM code.
     internal class RawData
@@ -421,4 +429,24 @@ public int MultiDimensionalArrayRank
             }
         }
     }
+
+    // Helper structs used for tail calls via helper.
+    [StructLayout(LayoutKind.Sequential)]
+    internal unsafe struct PortableTailCallFrame
+    {
+        public PortableTailCallFrame* Prev;
+        public IntPtr TailCallAwareReturnAddress;
+        public IntPtr NextCall;
+    }
+
+    [StructLayout(LayoutKind.Sequential)]
+    internal unsafe struct TailCallTls
+    {
+        public PortableTailCallFrame* Frame;
+        public IntPtr ArgBuffer;
+        private IntPtr _argBufferSize;
+        private IntPtr _argBufferGCDesc;
+        private fixed byte _argBufferInline[64];
+    }
+
 }

src/coreclr/src/System.Private.CoreLib/src/System/StubHelpers.cs

@@ -1878,5 +1878,8 @@ internal static void CheckStringLength(uint length)
         [MethodImpl(MethodImplOptions.InternalCall)]
         internal static extern void MulticastDebuggerTraceHelper(object o, int count);
 #endif
+
+        [MethodImplAttribute(MethodImplOptions.InternalCall)]
+        internal static extern IntPtr NextCallReturnAddress();
     }  // class StubHelpers
 }

src/coreclr/src/ToolBox/superpmi/superpmi-shared/icorjitinfoimpl.h

@@ -883,6 +883,12 @@ void MethodCompileComplete(CORINFO_METHOD_HANDLE methHnd);
 // return a thunk that will copy the arguments for the given signature.
 void* getTailCallCopyArgsThunk(CORINFO_SIG_INFO* pSig, CorInfoHelperTailCallSpecialHandling flags);
 
+bool getTailCallHelpers(
+    CORINFO_RESOLVED_TOKEN* callToken,
+    CORINFO_SIG_INFO* sig,
+    CORINFO_GET_TAILCALL_HELPERS_FLAGS flags,
+    CORINFO_TAILCALL_HELPERS* pResult);
+
 bool convertPInvokeCalliToCall(CORINFO_RESOLVED_TOKEN * pResolvedToken, bool fMustConvert);
 
 // get a block of memory for the code, readonly data, and read-write data

src/coreclr/src/ToolBox/superpmi/superpmi-shared/lwmlist.h

@@ -122,6 +122,7 @@ LWM(GetSharedCCtorHelper, DWORDLONG, DWORD)
 LWM(GetStringConfigValue, DWORD, DWORD)
 LWM(GetSystemVAmd64PassStructInRegisterDescriptor, DWORDLONG, Agnostic_GetSystemVAmd64PassStructInRegisterDescriptor)
 LWM(GetTailCallCopyArgsThunk, Agnostic_GetTailCallCopyArgsThunk, DWORDLONG)
+LWM(GetTailCallHelpers, Agnostic_GetTailCallHelpers, Agnostic_CORINFO_TAILCALL_HELPERS)
 LWM(GetThreadTLSIndex, DWORD, DLD)
 LWM(GetTokenTypeAsHandle, GetTokenTypeAsHandleValue, DWORDLONG)
 LWM(GetTypeForBox, DWORDLONG, DWORDLONG)

src/coreclr/src/ToolBox/superpmi/superpmi-shared/methodcontext.cpp

@@ -5956,12 +5956,14 @@ void MethodContext::recGetTailCallCopyArgsThunk(CORINFO_SIG_INFO*
     GetTailCallCopyArgsThunk->Add(key, (DWORDLONG)result);
     DEBUG_REC(dmpGetTailCallCopyArgsThunk(key, (DWORDLONG)result));
 }
+
 void MethodContext::dmpGetTailCallCopyArgsThunk(const Agnostic_GetTailCallCopyArgsThunk& key, DWORDLONG value)
 {
     printf("GetTailCallCopyArgsThunk key sig%s flg-%08X",
            SpmiDumpHelper::DumpAgnostic_CORINFO_SIG_INFO(key.Sig).c_str(), key.flags);
     printf(", value res-%016llX", value);
 }
+
 void* MethodContext::repGetTailCallCopyArgsThunk(CORINFO_SIG_INFO* pSig, CorInfoHelperTailCallSpecialHandling flags)
 {
     AssertCodeMsg(GetTailCallCopyArgsThunk != nullptr, EXCEPTIONCODE_MC, "Didn't find anything for ...");
@@ -5980,6 +5982,78 @@ void* MethodContext::repGetTailCallCopyArgsThunk(CORINFO_SIG_INFO* pSig, CorInfo
     return result;
 }
 
+void MethodContext::recGetTailCallHelpers(
+    CORINFO_RESOLVED_TOKEN* callToken,
+    CORINFO_SIG_INFO* sig,
+    CORINFO_GET_TAILCALL_HELPERS_FLAGS flags,
+    CORINFO_TAILCALL_HELPERS* pResult)
+{
+    if (GetTailCallHelpers == nullptr)
+        GetTailCallHelpers = new LightWeightMap<Agnostic_GetTailCallHelpers, Agnostic_CORINFO_TAILCALL_HELPERS>();
+
+    Agnostic_GetTailCallHelpers key;
+    ZeroMemory(&key, sizeof(Agnostic_GetTailCallHelpers));
+
+    key.callToken = SpmiRecordsHelper::StoreAgnostic_CORINFO_RESOLVED_TOKEN(callToken, GetTailCallHelpers);
+    key.sig = SpmiRecordsHelper::StoreAgnostic_CORINFO_SIG_INFO(*sig, GetTailCallHelpers);
+    key.flags = (DWORD)flags;
+
+    Agnostic_CORINFO_TAILCALL_HELPERS value;
+    ZeroMemory(&value, sizeof(Agnostic_CORINFO_TAILCALL_HELPERS));
+
+    value.result = pResult != nullptr;
+    if (pResult != nullptr)
+    {
+        value.flags = (DWORD)pResult->flags;
+        value.hStoreArgs = (DWORDLONG)pResult->hStoreArgs;
+        value.hCallTarget = (DWORDLONG)pResult->hCallTarget;
+        value.hDispatcher = (DWORDLONG)pResult->hDispatcher;
+    }
+    GetTailCallHelpers->Add(key, value);
+    DEBUG_REC(dmpGetTailCallHelpers(key, value));
+}
+
+void MethodContext::dmpGetTailCallHelpers(const Agnostic_GetTailCallHelpers& key, const Agnostic_CORINFO_TAILCALL_HELPERS& value)
+{
+    printf("GetTailCallHelpers key callToken-%s sig-%s flg-%08X",
+        SpmiDumpHelper::DumpAgnostic_CORINFO_RESOLVED_TOKEN(key.callToken).c_str(),
+        SpmiDumpHelper::DumpAgnostic_CORINFO_SIG_INFO(key.sig).c_str(),
+        key.flags);
+    printf(", value result-%s flg-%08X hStoreArgs-%016llX hCallTarget-%016llX hDispatcher-%016llX",
+        value.result ? "true" : "false",
+        value.flags,
+        value.hStoreArgs,
+        value.hCallTarget,
+        value.hDispatcher);
+}
+
+bool MethodContext::repGetTailCallHelpers(
+    CORINFO_RESOLVED_TOKEN* callToken,
+    CORINFO_SIG_INFO* sig,
+    CORINFO_GET_TAILCALL_HELPERS_FLAGS flags,
+    CORINFO_TAILCALL_HELPERS* pResult)
+{
+    AssertCodeMsg(GetTailCallHelpers != nullptr, EXCEPTIONCODE_MC, "Didn't find anything for ...");
+
+    Agnostic_GetTailCallHelpers key;
+    ZeroMemory(&key, sizeof(Agnostic_GetTailCallHelpers));
+    key.callToken = SpmiRecordsHelper::RestoreAgnostic_CORINFO_RESOLVED_TOKEN(callToken, GetTailCallHelpers);
+    key.sig = SpmiRecordsHelper::RestoreAgnostic_CORINFO_SIG_INFO(*sig, GetTailCallHelpers);
+    key.flags = (DWORD)flags;
+
+    AssertCodeMsg(GetTailCallHelpers->GetIndex(key) != -1, EXCEPTIONCODE_MC, "Could not find matching tail call helper call");
+    Agnostic_CORINFO_TAILCALL_HELPERS value = GetTailCallHelpers->Get(key);
+    if (!value.result)
+        return false;
+
+    pResult->flags = (CORINFO_TAILCALL_HELPERS_FLAGS)value.flags;
+    pResult->hStoreArgs = (CORINFO_METHOD_HANDLE)value.hStoreArgs;
+    pResult->hCallTarget = (CORINFO_METHOD_HANDLE)value.hCallTarget;
+    pResult->hDispatcher = (CORINFO_METHOD_HANDLE)value.hDispatcher;
+    DEBUG_REP(dmpGetTailCallHelpers(key, value));
+    return true;
+}
+
 void MethodContext::recGetMethodDefFromMethod(CORINFO_METHOD_HANDLE hMethod, mdMethodDef result)
 {
     if (GetMethodDefFromMethod == nullptr)

src/coreclr/src/ToolBox/superpmi/superpmi-shared/methodcontext.h

@@ -441,6 +441,20 @@ class MethodContext
         Agnostic_CORINFO_SIG_INFO Sig;
         DWORD                     flags;
     };
+    struct Agnostic_GetTailCallHelpers
+    {
+        Agnostic_CORINFO_RESOLVED_TOKEN callToken;
+        Agnostic_CORINFO_SIG_INFO sig;
+        DWORD flags;
+    };
+    struct Agnostic_CORINFO_TAILCALL_HELPERS
+    {
+        bool result;
+        DWORD flags;
+        DWORDLONG hStoreArgs;
+        DWORDLONG hCallTarget;
+        DWORDLONG hDispatcher;
+    };
     struct Agnostic_GetArgClass_Value
     {
         DWORDLONG result;
@@ -1259,6 +1273,18 @@ class MethodContext
     void dmpGetTailCallCopyArgsThunk(const Agnostic_GetTailCallCopyArgsThunk& key, DWORDLONG value);
     void* repGetTailCallCopyArgsThunk(CORINFO_SIG_INFO* pSig, CorInfoHelperTailCallSpecialHandling flags);
 
+    void recGetTailCallHelpers(
+        CORINFO_RESOLVED_TOKEN* callToken,
+        CORINFO_SIG_INFO* sig,
+        CORINFO_GET_TAILCALL_HELPERS_FLAGS flags,
+        CORINFO_TAILCALL_HELPERS* pResult);
+    void dmpGetTailCallHelpers(const Agnostic_GetTailCallHelpers& key, const Agnostic_CORINFO_TAILCALL_HELPERS& value);
+    bool repGetTailCallHelpers(
+        CORINFO_RESOLVED_TOKEN* callToken,
+        CORINFO_SIG_INFO* sig,
+        CORINFO_GET_TAILCALL_HELPERS_FLAGS flags,
+        CORINFO_TAILCALL_HELPERS* pResult);
+
     void recGetMethodDefFromMethod(CORINFO_METHOD_HANDLE hMethod, mdMethodDef result);
     void dmpGetMethodDefFromMethod(DWORDLONG key, DWORD value);
     mdMethodDef repGetMethodDefFromMethod(CORINFO_METHOD_HANDLE hMethod);
@@ -1320,7 +1346,7 @@ class MethodContext
 };
 
 // ********************* Please keep this up-to-date to ease adding more ***************
-// Highest packet number: 177
+// Highest packet number: 178
 // *************************************************************************************
 enum mcPackets
 {
@@ -1439,6 +1465,7 @@ enum mcPackets
     Packet_GetSecurityPrologHelper                       = 85, // Retired 2/18/2020
     Packet_GetSharedCCtorHelper                          = 86,
     Packet_GetTailCallCopyArgsThunk                      = 87,
+    Packet_GetTailCallHelpers                            = 178, // Added 3/18/2020
     Packet_GetThreadTLSIndex                             = 88,
     Packet_GetTokenTypeAsHandle                          = 89,
     Packet_GetTypeForBox                                 = 90,

src/coreclr/src/ToolBox/superpmi/superpmi-shim-collector/icorjitinfo.cpp

@@ -1866,6 +1866,21 @@ void* interceptor_ICJI::getTailCallCopyArgsThunk(CORINFO_SIG_INFO* pSig, CorInfo
     return result;
 }
 
+bool interceptor_ICJI::getTailCallHelpers(
+        CORINFO_RESOLVED_TOKEN* callToken,
+        CORINFO_SIG_INFO* sig,
+        CORINFO_GET_TAILCALL_HELPERS_FLAGS flags,
+        CORINFO_TAILCALL_HELPERS* pResult)
+{
+    mc->cr->AddCall("getTailCallHelpers");
+    bool result = original_ICorJitInfo->getTailCallHelpers(callToken, sig, flags, pResult);
+    if (result)
+        mc->recGetTailCallHelpers(callToken, sig, flags, pResult);
+    else
+        mc->recGetTailCallHelpers(callToken, sig, flags, nullptr);
+    return result;
+}
+
 // Stuff directly on ICorJitInfo
 
 // Returns extended flags for a particular compilation instance.

src/coreclr/src/ToolBox/superpmi/superpmi-shim-counter/icorjitinfo.cpp

@@ -1449,6 +1449,16 @@ void* interceptor_ICJI::getTailCallCopyArgsThunk(CORINFO_SIG_INFO* pSig, CorInfo
     return original_ICorJitInfo->getTailCallCopyArgsThunk(pSig, flags);
 }
 
+bool interceptor_ICJI::getTailCallHelpers(
+        CORINFO_RESOLVED_TOKEN* callToken,
+        CORINFO_SIG_INFO* sig,
+        CORINFO_GET_TAILCALL_HELPERS_FLAGS flags,
+        CORINFO_TAILCALL_HELPERS* pResult)
+{
+    mcs->AddCall("getTailCallHelpers");
+    return original_ICorJitInfo->getTailCallHelpers(callToken, sig, flags, pResult);
+}
+
 // Stuff directly on ICorJitInfo
 
 // Returns extended flags for a particular compilation instance.

src/coreclr/src/ToolBox/superpmi/superpmi-shim-simple/icorjitinfo.cpp

@@ -1291,6 +1291,15 @@ void* interceptor_ICJI::getTailCallCopyArgsThunk(CORINFO_SIG_INFO* pSig, CorInfo
     return original_ICorJitInfo->getTailCallCopyArgsThunk(pSig, flags);
 }
 
+bool interceptor_ICJI::getTailCallHelpers(
+        CORINFO_RESOLVED_TOKEN* callToken,
+        CORINFO_SIG_INFO* sig,
+        CORINFO_GET_TAILCALL_HELPERS_FLAGS flags,
+        CORINFO_TAILCALL_HELPERS* pResult)
+{
+    return original_ICorJitInfo->getTailCallHelpers(callToken, sig, flags, pResult);
+}
+
 // Stuff directly on ICorJitInfo
 
 // Returns extended flags for a particular compilation instance.

src/coreclr/src/ToolBox/superpmi/superpmi/icorjitinfo.cpp

@@ -1547,6 +1547,16 @@ void* MyICJI::getTailCallCopyArgsThunk(CORINFO_SIG_INFO* pSig, CorInfoHelperTail
     return jitInstance->mc->repGetTailCallCopyArgsThunk(pSig, flags);
 }
 
+bool MyICJI::getTailCallHelpers(
+        CORINFO_RESOLVED_TOKEN* callToken,
+        CORINFO_SIG_INFO* sig,
+        CORINFO_GET_TAILCALL_HELPERS_FLAGS flags,
+        CORINFO_TAILCALL_HELPERS* pResult)
+{
+    jitInstance->mc->cr->AddCall("getTailCallHelpers");
+    return jitInstance->mc->repGetTailCallHelpers(callToken, sig, flags, pResult);
+}
+
 bool MyICJI::convertPInvokeCalliToCall(CORINFO_RESOLVED_TOKEN* pResolvedToken, bool fMustConvert)
 {
     jitInstance->mc->cr->AddCall("convertPInvokeCalliToCall");