CPU/Recompiler: Add temporary inhibiting of register allocation

src/core/cpu_recompiler_code_generator.cpp

@@ -1433,6 +1433,7 @@ bool CodeGenerator::Compile_Divide(const CodeBlockInstruction& cbi)
 
     Value lo = m_register_cache.AllocateScratch(RegSize_32);
     Value hi = m_register_cache.AllocateScratch(RegSize_32);
+    m_register_cache.InhibitAllocation();
 
     LabelType do_divide, done;
 
@@ -1458,6 +1459,7 @@ bool CodeGenerator::Compile_Divide(const CodeBlockInstruction& cbi)
 
     EmitBindLabel(&done);
 
+    m_register_cache.UnunhibitAllocation();
     m_register_cache.WriteGuestRegister(Reg::lo, std::move(lo));
     m_register_cache.WriteGuestRegister(Reg::hi, std::move(hi));
   }
@@ -1488,6 +1490,7 @@ bool CodeGenerator::Compile_SignedDivide(const CodeBlockInstruction& cbi)
 
     Value lo = m_register_cache.AllocateScratch(RegSize_32);
     Value hi = m_register_cache.AllocateScratch(RegSize_32);
+    m_register_cache.InhibitAllocation();
 
     // we need this in a register on ARM because it won't fit in an immediate
     EmitCopyValue(lo.GetHostRegister(), Value::FromConstantU32(0x80000000u));
@@ -1538,6 +1541,7 @@ bool CodeGenerator::Compile_SignedDivide(const CodeBlockInstruction& cbi)
 
     EmitBindLabel(&done);
 
+    m_register_cache.UnunhibitAllocation();
     m_register_cache.WriteGuestRegister(Reg::lo, std::move(lo));
     m_register_cache.WriteGuestRegister(Reg::hi, std::move(hi));
   }

src/core/cpu_recompiler_register_cache.cpp

@@ -184,6 +184,9 @@ u32 RegisterCache::GetFreeHostRegisters() const
 
 HostReg RegisterCache::AllocateHostReg(HostRegState state /* = HostRegState::InUse */)
 {
+  if (m_state.allocator_inhibit_count > 0)
+    Panic("Allocating when inhibited");
+
   // try for a free register in allocation order
   for (u32 i = 0; i < m_state.available_count; i++)
   {
@@ -359,6 +362,7 @@ void RegisterCache::PushState()
   save_state.available_count = m_state.available_count;
   save_state.callee_saved_order_count = m_state.callee_saved_order_count;
   save_state.guest_reg_order_count = m_state.guest_reg_order_count;
+  save_state.allocator_inhibit_count = m_state.allocator_inhibit_count;
   save_state.load_delay_register = m_state.load_delay_register;
   save_state.load_delay_value.regcache = m_state.load_delay_value.regcache;
   save_state.load_delay_value.host_reg = m_state.load_delay_value.host_reg;
@@ -496,14 +500,15 @@ Value RegisterCache::ReadGuestRegisterToScratch(Reg guest_reg)
 
     if (cache_value.IsConstant())
     {
-      Log_DebugPrintf("Copying guest register %s from constant 0x%08X to scratch host register %s", GetRegName(guest_reg),
+      Log_DebugPrintf("Copying guest register %s from constant 0x%08X to scratch host register %s",
-                      static_cast<u32>(cache_value.constant_value),
+                      GetRegName(guest_reg), static_cast<u32>(cache_value.constant_value),
                       m_code_generator.GetHostRegName(host_reg, RegSize_32));
     }
     else
     {
       Log_DebugPrintf("Copying guest register %s from %s to scratch host register %s", GetRegName(guest_reg),
-                      m_code_generator.GetHostRegName(cache_value.host_reg, RegSize_32), m_code_generator.GetHostRegName(host_reg, RegSize_32));
+                      m_code_generator.GetHostRegName(cache_value.host_reg, RegSize_32),
+                      m_code_generator.GetHostRegName(host_reg, RegSize_32));
     }
   }
   else
@@ -796,4 +801,15 @@ void RegisterCache::AppendRegisterToOrder(Reg reg)
   m_state.guest_reg_order_count++;
 }
 
+void RegisterCache::InhibitAllocation()
+{
+  m_state.allocator_inhibit_count++;
+}
+
+void RegisterCache::UnunhibitAllocation()
+{
+  Assert(m_state.allocator_inhibit_count > 0);
+  m_state.allocator_inhibit_count--;
+}
+
 } // namespace CPU::Recompiler

src/core/cpu_recompiler_register_cache.h

@@ -317,6 +317,10 @@ public:
   void FlushAllGuestRegisters(bool invalidate, bool clear_dirty);
   bool EvictOneGuestRegister();
 
+  /// Temporarily prevents register allocation.
+  void InhibitAllocation();
+  void UnunhibitAllocation();
+
 private:
   void ClearRegisterFromOrder(Reg reg);
   void PushRegisterToOrder(Reg reg);
@@ -338,6 +342,7 @@ private:
     u32 available_count = 0;
     u32 callee_saved_order_count = 0;
     u32 guest_reg_order_count = 0;
+    u32 allocator_inhibit_count = 0;
 
     Reg load_delay_register = Reg::count;
     Value load_delay_value{};