[LoongArch64] Fix the ArgIteratorTemplate::GetNextOffset() return a…

…rgOfs for 'ELEMENT_TYPE_VALUETYPE' which is flattened liking struct{Arr[], float}. (#103108)

* [LoongArch64] Fix the `ArgIteratorTemplate::GetNextOffset()` return argOfs for 'ELEMENT_TYPE_VALUETYPE' which is flattened liking struct{Arr[], float}.
* The 'ELEMENT_TYPE_VALUETYPE' is marked to 'TYPE_GC_OTHER' and the first flattened element Arr[] should GC.
* This also fixed the assert failure "!CREATE_CHECK_STRING(pMT && pMT->Validate())" under GC=8 of MarshalStructAsLayoutSeq.sh.

* Update callingconvention.h

delete redundancy condition.

src/coreclr/tools/aot/ILCompiler.ReadyToRun/Compiler/DependencyAnalysis/ReadyToRun/ArgIterator.cs

@@ -1390,7 +1390,16 @@ public int GetNextOffset()
                                     _hasArgLocDescForStructInRegs = true;
                                     _argLocDescForStructInRegs.m_floatFlags = floatFieldFlags;
 
-                                    int argOfsInner = _transitionBlock.OffsetOfFloatArgumentRegisters + _loongarch64IdxFPReg * 8;
+                                    int argOfsInner = 0;
+                                    if ((floatFieldFlags & (uint)StructFloatFieldInfoFlags.STRUCT_FLOAT_FIELD_SECOND) != 0)
+                                    {
+                                        argOfsInner = _transitionBlock.OffsetOfArgumentRegisters + _loongarch64IdxGenReg * 8;
+                                    }
+                                    else
+                                    {
+                                        argOfsInner = _transitionBlock.OffsetOfFloatArgumentRegisters + _loongarch64IdxFPReg * 8;
+                                    }
+
                                     _loongarch64IdxFPReg++;
                                     _loongarch64IdxGenReg++;
                                     return argOfsInner;

src/coreclr/vm/callingconvention.h

@@ -308,6 +308,11 @@ struct TransitionBlock
         {
             return argLocDescForStructInRegs->m_cFloatReg > 0;
         }
+    #elif defined(TARGET_LOONGARCH64)
+        if (argLocDescForStructInRegs != NULL)
+        {
+            return argLocDescForStructInRegs->m_cFloatReg > 0;
+        }
     #endif
         return offset < 0;
     }
@@ -1719,16 +1724,24 @@ int ArgIteratorTemplate<ARGITERATOR_BASE>::GetNextOffset()
 
             if ((1 + m_idxFPReg <= NUM_ARGUMENT_REGISTERS) && (m_idxGenReg + 1 <= NUM_ARGUMENT_REGISTERS))
             {
+                int argOfs = 0;
                 m_argLocDescForStructInRegs.Init();
                 m_argLocDescForStructInRegs.m_idxFloatReg = m_idxFPReg;
                 m_argLocDescForStructInRegs.m_cFloatReg = 1;
-                int argOfs = TransitionBlock::GetOffsetOfFloatArgumentRegisters() + m_idxFPReg * 8;
-                m_idxFPReg += 1;
-
-                m_argLocDescForStructInRegs.m_structFields = flags;
-
                 m_argLocDescForStructInRegs.m_idxGenReg = m_idxGenReg;
                 m_argLocDescForStructInRegs.m_cGenReg = 1;
+                m_argLocDescForStructInRegs.m_structFields = flags;
+
+                if (flags & STRUCT_FLOAT_FIELD_SECOND)
+                {
+                    argOfs = TransitionBlock::GetOffsetOfArgumentRegisters() + m_idxGenReg * 8;
+                }
+                else
+                {
+                    argOfs = TransitionBlock::GetOffsetOfFloatArgumentRegisters() + m_idxFPReg * 8;
+                }
+
+                m_idxFPReg  += 1;
                 m_idxGenReg += 1;
 
                 m_hasArgLocDescForStructInRegs = true;

src/coreclr/vm/loongarch64/profiler.cpp

@@ -157,6 +157,27 @@ LPVOID ProfileArgIterator::GetNextArgAddr()
     if (TransitionBlock::IsArgumentRegisterOffset(argOffset))
     {
         pArg = (LPBYTE)&pData->argumentRegisters + (argOffset - TransitionBlock::GetOffsetOfArgumentRegisters());
+        ArgLocDesc* pArgLocDesc = m_argIterator.GetArgLocDescForStructInRegs();
+
+        if (pArgLocDesc)
+        {
+            if (pArgLocDesc->m_cFloatReg == 1)
+            {
+                _ASSERTE(!(pArgLocDesc->m_structFields & STRUCT_FLOAT_FIELD_FIRST));
+                _ASSERTE(pArgLocDesc->m_structFields & STRUCT_FLOAT_FIELD_SECOND);
+
+                UINT32 bufferPos = m_bufferPos;
+                UINT64* dst  = (UINT64*)&pData->buffer[bufferPos];
+                m_bufferPos += 16;
+
+                *dst = *(UINT64*)pArg;
+                *(double*)(dst + 1) = pData->floatArgumentRegisters.f[pArgLocDesc->m_idxFloatReg];
+
+                return (LPBYTE)&pData->buffer[bufferPos];
+            }
+
+            _ASSERTE(pArgLocDesc->m_cFloatReg == 0);
+        }
     }
     else
     {