[WIP] Revert Interpreter Code Changes

src/coreclr/vm/interpreter.cpp

@@ -1635,46 +1635,7 @@ CorJitResult Interpreter::GenerateInterpreterStub(CEEInfo* comp,
 #elif defined(HOST_LOONGARCH64)
         assert(!"unimplemented on LOONGARCH yet");
 #elif defined(HOST_RISCV64)
-        UINT stackFrameSize = argState.numFPRegArgSlots;
-
-        sl.EmitProlog(argState.numRegArgs, argState.numFPRegArgSlots, 0 /*cCalleeSavedRegs*/, 0);
-
-#if INTERP_ILSTUBS
-        if (pMD->IsILStub())
-        {
-            // Third argument(x12) is stubcontext, in x7 (METHODDESC_REGISTER)
-            sl.EmitMovReg(IntReg(12), IntReg(7));
-        }
-        else
-#endif
-        {
-            // For a non-ILStub method, push NULL as the third stubContext argument
-            sl.EmitMovConstant(IntReg(12), 0);
-        }
-
-        // Second arg is pointer to the basei of the ILArgs -- i.e., the current stack value
-        // sl.EmitAddImm(IntReg(1), RegSp, sl.GetSavedRegArgsOffset());
-
-        // First arg is the pointer to the interpMethodInfo structure
-#if INTERP_ILSTUBS
-        if (!pMD->IsILStub())
-#endif
-        {
-            // interpMethodInfo is already in x8, so copy it from x8
-            sl.EmitMovReg(IntReg(10), IntReg(8)); // TODO what is x8???
-        }
-#if INTERP_ILSTUBS
-        else
-        {
-            // We didn't do the short-circuiting, therefore interpMethInfo is
-            // not stored in a register (x8) before. so do it now.
-            sl.EmitMovConstant(IntReg(10), reinterpret_cast<UINT64>(interpMethInfo));
-        }
-#endif
-
-        sl.EmitCallLabel(sl.NewExternalCodeLabel((LPVOID)interpretMethodFunc), FALSE, FALSE);
-
-        sl.EmitEpilog();
+        assert(!"unimplemented on RISCV64 yet");
 #else
 #error unsupported platform
 #endif

src/coreclr/vm/riscv64/cgencpu.h

@@ -377,16 +377,7 @@ class StubLinkerCPU : public StubLinker
     void EmitLoadRegReg(IntReg Xt, IntReg Xn, IntReg Xm, DWORD option);
 
     void EmitCallRegister(IntReg reg);
-    void EmitProlog(unsigned short cIntRegArgs,
-                    unsigned short cFloatRegArgs,
-                    unsigned short cCalleeSavedRegs,
-                    unsigned short cbStackSpace = 0);
-
-    void EmitEpilog();
-
     void EmitRet(IntReg reg);
-
-
 };
 #endif
 

src/coreclr/vm/riscv64/stubs.cpp

@@ -479,115 +479,6 @@ void StubLinkerCPU::EmitJumpRegister(IntReg regTarget)
     _ASSERTE(!"RISCV64: not implementation on riscv64!!!");
 }
 
-void StubLinkerCPU::EmitProlog(unsigned short cIntRegArgs, unsigned short cFloatRegArgs, unsigned short cCalleeSavedRegs, unsigned short cbStackSpace)
-{
-    _ASSERTE(!m_fProlog);
-
-    unsigned short numberOfEntriesOnStack  = 2 + cIntRegArgs + cFloatRegArgs + cCalleeSavedRegs; // 2 for fp, ra
-
-    // Stack needs to be 16 byte (2 qword) aligned. Compute the required padding before saving it
-    unsigned short totalPaddedFrameSize = static_cast<unsigned short>(ALIGN_UP(cbStackSpace + numberOfEntriesOnStack *sizeof(void*), 2 * sizeof(void*)));
-    // The padding is going to be applied to the local stack
-    cbStackSpace =  totalPaddedFrameSize - numberOfEntriesOnStack * sizeof(void*);
-
-    // Record the parameters of this prolog so that we can generate a matching epilog and unwind info.
-    DescribeProlog(cIntRegArgs, cFloatRegArgs, cCalleeSavedRegs, cbStackSpace);
-
-
-    // N.B Despite the range of a jump with a sub sp is 4KB, we're limiting to 504 to save from emitting right prolog that's
-    // expressable in unwind codes efficiently. The largest offset in typical unwindinfo encodings that we use is 504.
-    // so allocations larger than 504 bytes would require setting the SP in multiple strides, which would complicate both
-    // prolog and epilog generation as well as unwindinfo generation.
-    _ASSERTE((totalPaddedFrameSize <= 504) && "NYI:RISCV64 Implement StubLinker prologs with larger than 504 bytes of frame size");
-    if (totalPaddedFrameSize > 504)
-        COMPlusThrow(kNotSupportedException);
-
-    // Regarding the order of operations in the prolog and epilog;
-    // If the prolog and the epilog matches each other we can simplify emitting the unwind codes and save a few
-    // bytes of unwind codes by making prolog and epilog share the same unwind codes.
-    // In order to do that we need to make the epilog be the reverse of the prolog.
-    // But we wouldn't want to add restoring of the argument registers as that's completely unnecessary.
-    // Besides, saving argument registers cannot be expressed by the unwind code encodings.
-    // So, we'll push saving the argument registers to the very last in the prolog, skip restoring it in epilog,
-    // and also skip reporting it to the OS.
-    //
-    // Another bit that we can save is resetting the frame pointer.
-    // This is not necessary when the SP doesn't get modified beyond prolog and epilog. (i.e no alloca/localloc)
-    // And in that case we don't need to report setting up the FP either.
-
-
-    // 1. Relocate SP
-    EmitSubImm(RegSp, RegSp, totalPaddedFrameSize);
-
-    unsigned cbOffset = 2 * sizeof(void*) + cbStackSpace; // 2 is for fp, ra
-
-    // 2. Store callee-saved registers
-#if 0
-    _ASSERTE(cCalleeSavedRegs <= 13);
-    if (cCalleeSavedRegs != 0)
-    {
-        EmitLoadStoreRegPairImm(eSTORE, IntReg(3), IntReg(4), RegSp, cbOffset);
-        EmitLoadStoreRegPairImm(eSTORE, IntReg(9), IntReg(18), RegSp, cbOffset + 2 * sizeof(void*));
-        EmitLoadStoreRegPairImm(eSTORE, IntReg(19), IntReg(20), RegSp, cbOffset + 4 * sizeof(void*));
-        EmitLoadStoreRegPairImm(eSTORE, IntReg(21), IntReg(22), RegSp, cbOffset + 6 * sizeof(void*));
-        EmitLoadStoreRegPairImm(eSTORE, IntReg(23), IntReg(24), RegSp, cbOffset + 8 * sizeof(void*));
-        EmitLoadStoreRegPairImm(eSTORE, IntReg(25), IntReg(26), RegSp, cbOffset + 10 * sizeof(void*));
-        EmitLoadStoreRegImm(eSTORE, IntReg(27), RegSp, cbOffset + 12 * sizeof(void*));
-    }
-#endif
-
-    // 3. Store FP/RA
-    EmitLoadStoreRegPairImm(eSTORE, RegFp, RegRa, RegSp, cbStackSpace);
-
-    // 4. Set the frame pointer
-    EmitMovReg(RegFp, RegSp);
-
-    // 5. Store floating point argument registers
-    cbOffset += cCalleeSavedRegs * sizeof(void*);
-    _ASSERTE(cFloatRegArgs <= 8);
-    for (unsigned short i = 0; i < (cFloatRegArgs / 2) * 2; i += 2)
-        EmitLoadStoreRegPairImm(eSTORE, FloatReg(i + 10), FloatReg(i + 11), RegSp, cbOffset + i * sizeof(void*));
-    if ((cFloatRegArgs % 2) == 1)
-        EmitLoadStoreRegImm(eSTORE, FloatReg(cFloatRegArgs - 1 + 10), RegSp, cbOffset + (cFloatRegArgs - 1) * sizeof(void*));
-
-    // 6. Store int argument registers
-    cbOffset += cFloatRegArgs * sizeof(void*);
-    _ASSERTE(cIntRegArgs <= 8);
-    for (unsigned short i = 0 ; i < (cIntRegArgs / 2) * 2; i += 2)
-        EmitLoadStoreRegPairImm(eSTORE, IntReg(i + 10), IntReg(i + 11), RegSp, cbOffset + i * sizeof(void*));
-    if ((cIntRegArgs % 2) == 1)
-        EmitLoadStoreRegImm(eSTORE,IntReg(cIntRegArgs-1 + 10), RegSp, cbOffset + (cIntRegArgs - 1) * sizeof(void*));
-}
-
-void StubLinkerCPU::EmitEpilog()
-{
-    _ASSERTE(m_fProlog);
-
-    // 6. Restore int argument registers
-    //    nop: We don't need to. They are scratch registers
-
-    // 5. Restore floating point argument registers
-    //    nop: We don't need to. They are scratch registers
-
-    // 4. Restore the SP from FP
-    //    N.B. We're assuming that the stublinker stubs doesn't do alloca, hence nop
-
-    // 3. Restore FP/RA
-    EmitLoadStoreRegPairImm(eLOAD, RegFp, RegRa, RegSp, m_cbStackSpace);
-
-    // 2. restore the calleeSavedRegisters
-    unsigned cbOffset = 2*sizeof(void*) + m_cbStackSpace; // 2 is for fp,lr
-    if ((m_cCalleeSavedRegs % 2) ==1)
-        EmitLoadStoreRegImm(eLOAD, IntReg(m_cCalleeSavedRegs - 1), RegSp, cbOffset + (m_cCalleeSavedRegs - 1) * sizeof(void*));
-    for (int i = (m_cCalleeSavedRegs / 2) * 2 - 2; i >= 0; i -= 2)
-        EmitLoadStoreRegPairImm(eLOAD, IntReg(19 + i), IntReg(19 + i + 1), RegSp, cbOffset + i * sizeof(void*));
-
-    // 1. Restore SP
-    EmitAddImm(RegSp, RegSp, GetStackFrameSize());
-    EmitRet(RegRa);
-;
-}
-
 void StubLinkerCPU::EmitRet(IntReg Xn)
 {
     Emit32((DWORD)(0x00000067 | (Xn << 15))); // jalr X0, 0(Xn)

src/coreclr/vm/stublink.cpp

@@ -377,13 +377,6 @@ StubLinker::StubLinker()
     m_cbStackSpace      = 0;
 #endif
 #endif // STUBLINKER_GENERATES_UNWIND_INFO
-#ifdef TARGET_RISCV64
-    m_fProlog           = FALSE;
-    m_cIntRegArgs       = 0;
-    m_cFloatRegArgs     = 0;
-    m_cCalleeSavedRegs  = 0;
-    m_cbStackSpace      = 0;
-#endif
 }
 
 
@@ -1898,31 +1891,7 @@ UINT StubLinker::GetStackFrameSize()
     return m_cbStackSpace + (2 + m_cCalleeSavedRegs + m_cIntRegArgs + m_cVecRegArgs)*sizeof(void*);
 }
 
-#elif defined(TARGET_RISCV64)
-void StubLinker::DescribeProlog(UINT cIntRegArgs, UINT cFloatRegArgs, UINT cCalleeSavedRegs, UINT cbStackSpace)
-{
-    m_fProlog               = TRUE;
-    m_cIntRegArgs           = cIntRegArgs;
-    m_cFloatRegArgs         = cFloatRegArgs;
-    m_cCalleeSavedRegs      = cCalleeSavedRegs;
-    m_cbStackSpace          = cbStackSpace;
-}
-
-UINT StubLinker::GetSavedRegArgsOffset()
-{
-    _ASSERTE(m_fProlog);
-    // This is the offset from SP
-    // We're assuming that the stublinker will push the arg registers to the bottom of the stack frame
-    return m_cbStackSpace +  (2 + m_cCalleeSavedRegs)*sizeof(void*); // 2 is for FP and RA
-}
-
-UINT StubLinker::GetStackFrameSize()
-{
-    _ASSERTE(m_fProlog);
-    return m_cbStackSpace + (2 + m_cCalleeSavedRegs + m_cIntRegArgs + m_cFloatRegArgs) * sizeof(void*);
-}
-
-#endif // ifdef TARGET_ARM, elif defined(TARGET_ARM64), elif defined(TARGET_RISCV64)
+#endif // ifdef TARGET_ARM, elif defined(TARGET_ARM64)
 
 #endif // #ifndef DACCESS_COMPILE
 

src/coreclr/vm/stublink.h

@@ -229,10 +229,6 @@ class StubLinker
         void DescribeProlog(UINT cIntRegArgs, UINT cVecRegArgs, UINT cCalleeSavedRegs, UINT cbStackFrame);
         UINT GetSavedRegArgsOffset();
         UINT GetStackFrameSize();
-#elif defined(TARGET_RISCV64)
-        void DescribeProlog(UINT cIntRegArgs, UINT cFloatRegArgs, UINT cCalleeSavedRegs, UINT cbStackFrame);
-        UINT GetSavedRegArgsOffset();
-        UINT GetStackFrameSize();
 #endif
 
         //===========================================================================
@@ -308,17 +304,6 @@ class StubLinker
         UINT            m_cbStackSpace;         // Additional stack space for return buffer and stack alignment
 #endif // TARGET_ARM64
 
-#ifdef TARGET_RISCV64
-protected:
-        BOOL            m_fProlog;              // True if DescribeProlog has been called
-        UINT            m_cIntRegArgs;          // Count of int register arguments (a0 - a7)
-        UINT            m_cFloatRegArgs;        // Count of FP register arguments (fa0 - fa7)
-        UINT            m_cCalleeSavedRegs;     // Count of callee saved registers (sp, gp, tp, s0 - s11)
-        UINT            m_cbStackSpace;         // Additional stack space for return buffer and stack alignment
-#endif // TARGET_ARM64
-
-
-
 #ifdef STUBLINKER_GENERATES_UNWIND_INFO
 
 #ifdef _DEBUG