JIT: Remove TYP_BLK and TYP_LCLBLK

src/coreclr/jit/codegencommon.cpp

@@ -3042,7 +3042,7 @@ void CodeGen::genFnPrologCalleeRegArgs(regNumber xtraReg, bool* pXtraRegClobbere
 #if defined(UNIX_AMD64_ABI)
         if (varTypeIsStruct(varDsc))
         {
-            CORINFO_CLASS_HANDLE typeHnd = varDsc->GetStructHnd();
+            CORINFO_CLASS_HANDLE typeHnd = varDsc->GetLayout()->GetClassHandle();
             assert(typeHnd != nullptr);
             SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR structDesc;
             compiler->eeGetSystemVAmd64PassStructInRegisterDescriptor(typeHnd, &structDesc);
@@ -3350,7 +3350,7 @@ void CodeGen::genFnPrologCalleeRegArgs(regNumber xtraReg, bool* pXtraRegClobbere
                 {
                     // This must be a SIMD type that's fully enregistered, but is passed as an HFA.
                     // Each field will be inserted into the same destination register.
-                    assert(varTypeIsSIMD(varDsc) && !compiler->isOpaqueSIMDType(varDsc->GetStructHnd()));
+                    assert(varTypeIsSIMD(varDsc) && !compiler->isOpaqueSIMDType(varDsc->GetLayout()));
                     assert(regArgTab[argNum].slot <= (int)varDsc->lvHfaSlots());
                     assert(argNum > 0);
                     assert(regArgTab[argNum - 1].varNum == varNum);

src/coreclr/jit/codegenxarch.cpp

@@ -6361,7 +6361,7 @@ void CodeGen::genJmpMethod(GenTree* jmp)
 #if defined(UNIX_AMD64_ABI)
         if (varTypeIsStruct(varDsc))
         {
-            CORINFO_CLASS_HANDLE typeHnd = varDsc->GetStructHnd();
+            CORINFO_CLASS_HANDLE typeHnd = varDsc->GetLayout()->GetClassHandle();
             assert(typeHnd != nullptr);
 
             SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR structDesc;
@@ -6411,9 +6411,9 @@ void CodeGen::genJmpMethod(GenTree* jmp)
             // Register argument
             CLANG_FORMAT_COMMENT_ANCHOR;
 #ifdef TARGET_X86
-            noway_assert(
-                isRegParamType(genActualType(varDsc->TypeGet())) ||
-                (varTypeIsStruct(varDsc->TypeGet()) && compiler->isTrivialPointerSizedStruct(varDsc->GetStructHnd())));
+            noway_assert(isRegParamType(genActualType(varDsc->TypeGet())) ||
+                         ((varDsc->TypeGet() == TYP_STRUCT) &&
+                          compiler->isTrivialPointerSizedStruct(varDsc->GetLayout()->GetClassHandle())));
 #else
             noway_assert(isRegParamType(genActualType(varDsc->TypeGet())));
 #endif // TARGET_X86

src/coreclr/jit/compiler.cpp

@@ -10280,6 +10280,10 @@ void Compiler::EnregisterStats::RecordLocal(const LclVarDsc* varDsc)
                     m_stressPoisonImplicitByrefs++;
                     break;
 
+                case AddressExposedReason::EXTERNALLY_VISIBLE_IMPLICITLY:
+                    m_externallyVisibleImplicitly++;
+                    break;
+
                 default:
                     unreached();
                     break;
@@ -10376,5 +10380,6 @@ void Compiler::EnregisterStats::Dump(FILE* fout) const
     PRINT_STATS(m_stressLclFld, m_addrExposed);
     PRINT_STATS(m_dispatchRetBuf, m_addrExposed);
     PRINT_STATS(m_stressPoisonImplicitByrefs, m_addrExposed);
+    PRINT_STATS(m_externallyVisibleImplicitly, m_addrExposed);
 }
 #endif // TRACK_ENREG_STATS

src/coreclr/jit/compiler.h

@@ -476,6 +476,9 @@ enum class AddressExposedReason
     STRESS_LCL_FLD,                // Stress mode replaces localVar with localFld and makes them addrExposed.
     DISPATCH_RET_BUF,              // Caller return buffer dispatch.
     STRESS_POISON_IMPLICIT_BYREFS, // This is an implicit byref we want to poison.
+    EXTERNALLY_VISIBLE_IMPLICITLY, // Local is visible externally without explicit escape in JIT IR.
+                                   // For example because it is used by GC or is the outgoing arg area
+                                   // that belongs to callees.
 };
 
 #endif // DEBUG
@@ -1082,6 +1085,7 @@ class LclVarDsc
         lvStkOffs = offset;
     }
 
+    // TODO-Cleanup: Remove this in favor of GetLayout()->Size/genTypeSize(lvType).
     unsigned lvExactSize; // (exact) size of a STRUCT/SIMD/BLK local in bytes.
 
     unsigned lvSize() const;
@@ -1090,25 +1094,9 @@ class LclVarDsc
 
     unsigned lvSlotNum; // original slot # (if remapped)
 
-    // class handle for the local or null if not known or not a class,
-    // for a struct handle use `GetStructHnd()`.
+    // class handle for the local or null if not known or not a class
     CORINFO_CLASS_HANDLE lvClassHnd;
 
-    // Get class handle for a struct local or implicitByRef struct local.
-    CORINFO_CLASS_HANDLE GetStructHnd() const
-    {
-#ifdef FEATURE_SIMD
-        if (lvSIMDType && (m_layout == nullptr))
-        {
-            return NO_CLASS_HANDLE;
-        }
-#endif
-
-        CORINFO_CLASS_HANDLE structHnd = GetLayout()->GetClassHandle();
-        assert(structHnd != NO_CLASS_HANDLE);
-        return structHnd;
-    }
-
 private:
     ClassLayout* m_layout; // layout info for structs
 
@@ -1191,6 +1179,16 @@ class LclVarDsc
         m_layout = layout;
     }
 
+    // Grow the size of a block layout local.
+    void GrowBlockLayout(ClassLayout* layout)
+    {
+        assert(varTypeIsStruct(lvType));
+        assert((m_layout == nullptr) || (m_layout->IsBlockLayout() && (m_layout->GetSize() <= layout->GetSize())));
+        assert(layout->IsBlockLayout());
+        m_layout    = layout;
+        lvExactSize = layout->GetSize();
+    }
+
     SsaDefArray<LclSsaVarDsc> lvPerSsaData;
 
     // Returns the address of the per-Ssa data for the given ssaNum (which is required
@@ -3272,7 +3270,7 @@ class Compiler
                                         // or if the inlinee has GC ref locals.
 
 #if FEATURE_FIXED_OUT_ARGS
-    unsigned            lvaOutgoingArgSpaceVar;  // dummy TYP_LCLBLK var for fixed outgoing argument space
+    unsigned            lvaOutgoingArgSpaceVar;  // var that represents outgoing argument space
     PhasedVar<unsigned> lvaOutgoingArgSpaceSize; // size of fixed outgoing argument space
 #endif                                           // FEATURE_FIXED_OUT_ARGS
 
@@ -3309,7 +3307,7 @@ class Compiler
 
 #if !defined(FEATURE_EH_FUNCLETS)
     // This is used for the callable handlers
-    unsigned lvaShadowSPslotsVar; // TYP_BLK variable for all the shadow SP slots
+    unsigned lvaShadowSPslotsVar; // Block-layout TYP_STRUCT variable for all the shadow SP slots
 #endif                            // FEATURE_EH_FUNCLETS
 
     int lvaCachedGenericContextArgOffs;
@@ -3520,7 +3518,7 @@ class Compiler
     bool lvaIsMultiregStruct(LclVarDsc* varDsc, bool isVararg);
 
     // If the local is a TYP_STRUCT, get/set a class handle describing it
-    CORINFO_CLASS_HANDLE lvaGetStruct(unsigned varNum);
+    void lvaSetStruct(unsigned varNum, ClassLayout* layout, bool unsafeValueClsCheck);
     void lvaSetStruct(unsigned varNum, CORINFO_CLASS_HANDLE typeHnd, bool unsafeValueClsCheck);
     void lvaSetStructUsedAsVarArg(unsigned varNum);
 
@@ -8715,14 +8713,30 @@ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
         return true;
     }
 
+    bool isOpaqueSIMDType(ClassLayout* layout) const
+    {
+        if (layout->IsBlockLayout())
+        {
+            return true;
+        }
+
+        return isOpaqueSIMDType(layout->GetClassHandle());
+    }
+
     // Returns true if the lclVar is an opaque SIMD type.
     bool isOpaqueSIMDLclVar(const LclVarDsc* varDsc) const
     {
         if (!varDsc->lvSIMDType)
         {
             return false;
         }
-        return isOpaqueSIMDType(varDsc->GetStructHnd());
+
+        if (varDsc->GetLayout() == nullptr)
+        {
+            return true;
+        }
+
+        return isOpaqueSIMDType(varDsc->GetLayout());
     }
 
     bool isNumericsNamespace(const char* ns)
@@ -10328,6 +10342,7 @@ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
         unsigned m_dispatchRetBuf;
         unsigned m_wideIndir;
         unsigned m_stressPoisonImplicitByrefs;
+        unsigned m_externallyVisibleImplicitly;
 
     public:
         void RecordLocal(const LclVarDsc* varDsc);

src/coreclr/jit/flowgraph.cpp

@@ -1894,9 +1894,8 @@ void Compiler::fgAddReversePInvokeEnterExit()
 
     lvaReversePInvokeFrameVar = lvaGrabTempWithImplicitUse(false DEBUGARG("Reverse Pinvoke FrameVar"));
 
-    LclVarDsc* varDsc   = lvaGetDesc(lvaReversePInvokeFrameVar);
-    varDsc->lvType      = TYP_BLK;
-    varDsc->lvExactSize = eeGetEEInfo()->sizeOfReversePInvokeFrame;
+    LclVarDsc* varDsc = lvaGetDesc(lvaReversePInvokeFrameVar);
+    lvaSetStruct(lvaReversePInvokeFrameVar, typGetBlkLayout(eeGetEEInfo()->sizeOfReversePInvokeFrame), false);
 
     // Add enter pinvoke exit callout at the start of prolog
 
@@ -2667,9 +2666,8 @@ PhaseStatus Compiler::fgAddInternal()
         lvaSetVarAddrExposed(lvaInlinedPInvokeFrameVar DEBUGARG(AddressExposedReason::ESCAPE_ADDRESS));
 
         LclVarDsc* varDsc = lvaGetDesc(lvaInlinedPInvokeFrameVar);
-        varDsc->lvType    = TYP_BLK;
         // Make room for the inlined frame.
-        varDsc->lvExactSize = eeGetEEInfo()->inlinedCallFrameInfo.size;
+        lvaSetStruct(lvaInlinedPInvokeFrameVar, typGetBlkLayout(eeGetEEInfo()->inlinedCallFrameInfo.size), false);
 #if FEATURE_FIXED_OUT_ARGS
         // Grab and reserve space for TCB, Frame regs used in PInvoke epilog to pop the inlined frame.
         // See genPInvokeMethodEpilog() for use of the grabbed var. This is only necessary if we are
@@ -2678,8 +2676,7 @@ PhaseStatus Compiler::fgAddInternal()
         {
             lvaPInvokeFrameRegSaveVar = lvaGrabTempWithImplicitUse(false DEBUGARG("PInvokeFrameRegSave Var"));
             varDsc                    = lvaGetDesc(lvaPInvokeFrameRegSaveVar);
-            varDsc->lvType            = TYP_BLK;
-            varDsc->lvExactSize       = 2 * REGSIZE_BYTES;
+            lvaSetStruct(lvaPInvokeFrameRegSaveVar, typGetBlkLayout(2 * REGSIZE_BYTES), false);
         }
 #endif
     }
@@ -3043,6 +3040,7 @@ PhaseStatus Compiler::fgSimpleLowering()
     // attempt later will cause an assert.
     lvaOutgoingArgSpaceSize = outgoingArgSpaceSize;
     lvaOutgoingArgSpaceSize.MarkAsReadOnly();
+    lvaGetDesc(lvaOutgoingArgSpaceVar)->GrowBlockLayout(typGetBlkLayout(outgoingArgSpaceSize));
 
 #endif // FEATURE_FIXED_OUT_ARGS
 

src/coreclr/jit/gcencode.cpp

@@ -4183,7 +4183,8 @@ void GCInfo::gcMakeRegPtrTable(
 
         // If this is a TYP_STRUCT, handle its GC pointers.
         // Note that the enregisterable struct types cannot have GC pointers in them.
-        if ((varDsc->TypeGet() == TYP_STRUCT) && varDsc->lvOnFrame && (varDsc->lvExactSize >= TARGET_POINTER_SIZE))
+        if ((varDsc->TypeGet() == TYP_STRUCT) && varDsc->GetLayout()->HasGCPtr() && varDsc->lvOnFrame &&
+            (varDsc->lvExactSize >= TARGET_POINTER_SIZE))
         {
             ClassLayout* layout = varDsc->GetLayout();
             unsigned     slots  = layout->GetSlotCount();

src/coreclr/jit/gentree.cpp

@@ -11302,27 +11302,6 @@ void Compiler::gtDispLclVarStructType(unsigned lclNum)
         assert(layout != nullptr);
         gtDispClassLayout(layout, type);
     }
-    else if (type == TYP_LCLBLK)
-    {
-#if FEATURE_FIXED_OUT_ARGS
-        assert(lclNum == lvaOutgoingArgSpaceVar);
-        // Since lvaOutgoingArgSpaceSize is a PhasedVar we can't read it for Dumping until
-        // after we set it to something.
-        if (lvaOutgoingArgSpaceSize.HasFinalValue())
-        {
-            // A PhasedVar<T> can't be directly used as an arg to a variadic function
-            unsigned value = lvaOutgoingArgSpaceSize;
-            printf("<%u> ", value);
-        }
-        else
-        {
-            printf("<na> "); // The value hasn't yet been determined
-        }
-#else
-        assert(!"Unknown size");
-        NO_WAY("Target doesn't support TYP_LCLBLK");
-#endif // FEATURE_FIXED_OUT_ARGS
-    }
 }
 
 #if defined(DEBUG) && defined(TARGET_ARM64)
@@ -11719,7 +11698,7 @@ void Compiler::gtDispLeaf(GenTree* tree, IndentStack* indentStack)
                         else
 #endif // !defined(TARGET_64BIT)
                         {
-                            CORINFO_CLASS_HANDLE typeHnd = varDsc->GetStructHnd();
+                            CORINFO_CLASS_HANDLE typeHnd = varDsc->GetLayout()->GetClassHandle();
                             CORINFO_FIELD_HANDLE fldHnd =
                                 info.compCompHnd->getFieldInClass(typeHnd, fieldVarDsc->lvFldOrdinal);
                             fieldName = eeGetFieldName(fldHnd, true, buffer, sizeof(buffer));
@@ -15813,6 +15792,21 @@ GenTree* Compiler::gtNewTempAssign(
     if (dstTyp == TYP_UNDEF)
     {
         varDsc->lvType = dstTyp = genActualType(valTyp);
+
+        if (varTypeIsStruct(dstTyp))
+        {
+            if (varTypeIsSIMD(dstTyp))
+            {
+                varDsc->lvExactSize = genTypeSize(dstTyp);
+#ifdef FEATURE_SIMD
+                varDsc->lvSIMDType = 1;
+#endif
+            }
+            else
+            {
+                lvaSetStruct(tmp, val->GetLayout(this), false);
+            }
+        }
     }
 
 #if FEATURE_SIMD
@@ -15880,40 +15874,13 @@ GenTree* Compiler::gtNewTempAssign(
     GenTree* asg;
     GenTree* dest = gtNewLclvNode(tmp, dstTyp);
 
-    // With first-class structs, we should be propagating the class handle on all non-primitive
-    // struct types. We don't have a convenient way to do that for all SIMD temps, since some
-    // internal trees use SIMD types that are not used by the input IL. In this case, we allow
-    // a null type handle and derive the necessary information about the type from its varType.
-    CORINFO_CLASS_HANDLE valStructHnd = gtGetStructHandleIfPresent(val);
-    if (varTypeIsStruct(varDsc) && (valStructHnd == NO_CLASS_HANDLE) && !varTypeIsSIMD(valTyp))
-    {
-        // There are some cases where we do not have a struct handle on the return value:
-        // 1. Handle-less BLK/LCL_FLD nodes.
-        // 2. The zero constant created by local assertion propagation.
-        // In these cases, we can use the type of the local for the assignment.
-        assert(val->gtEffectiveVal(true)->OperIs(GT_IND, GT_BLK, GT_LCL_FLD, GT_CNS_INT));
-        valStructHnd = lvaGetDesc(tmp)->GetStructHnd();
-        assert(valStructHnd != NO_CLASS_HANDLE);
-    }
-
-    if ((valStructHnd != NO_CLASS_HANDLE) && val->IsConstInitVal())
+    if (val->IsConstInitVal())
     {
         asg = gtNewAssignNode(dest, val);
     }
-    else if (varTypeIsStruct(varDsc) && ((valStructHnd != NO_CLASS_HANDLE) || varTypeIsSIMD(valTyp)))
+    else if (varTypeIsStruct(varDsc))
     {
-        // The struct value may be be a child of a GT_COMMA due to explicit null checks of indirs/fields.
         GenTree* valx = val->gtEffectiveVal(/*commaOnly*/ true);
-
-        if (valStructHnd != NO_CLASS_HANDLE)
-        {
-            lvaSetStruct(tmp, valStructHnd, false);
-        }
-        else
-        {
-            assert(valx->gtOper != GT_OBJ);
-        }
-
         valx->gtFlags |= GTF_DONT_CSE;
         asg = impAssignStruct(dest, val, CHECK_SPILL_NONE, pAfterStmt, di, block);
     }
@@ -17705,8 +17672,14 @@ CORINFO_CLASS_HANDLE Compiler::gtGetStructHandleIfPresent(GenTree* tree)
                 }
                 break;
             case GT_LCL_VAR:
-                structHnd = lvaGetDesc(tree->AsLclVar())->GetStructHnd();
+            {
+                LclVarDsc* dsc = lvaGetDesc(tree->AsLclVar());
+                if ((dsc->GetLayout() != nullptr) && !dsc->GetLayout()->IsBlockLayout())
+                {
+                    structHnd = dsc->GetLayout()->GetClassHandle();
+                }
                 break;
+            }
             case GT_RETURN:
                 structHnd = gtGetStructHandleIfPresent(tree->AsOp()->gtOp1);
                 break;

src/coreclr/jit/gschecks.cpp

@@ -454,7 +454,7 @@ void Compiler::gsParamsToShadows()
         {
             // We don't need unsafe value cls check here since we are copying the params and this flag
             // would have been set on the original param before reaching here.
-            lvaSetStruct(shadowVarNum, varDsc->GetStructHnd(), false);
+            lvaSetStruct(shadowVarNum, varDsc->GetLayout(), false);
             shadowVarDsc->lvIsMultiRegArg = varDsc->lvIsMultiRegArg;
             shadowVarDsc->lvIsMultiRegRet = varDsc->lvIsMultiRegRet;
         }