IR: Add Breakpoint IR instruction (for debugging purposes, emits a host-breakpoint)

src/backend_x64/emit_x64.cpp

@@ -87,6 +87,10 @@ CodePtr EmitX64::Emit(const Arm::LocationDescriptor descriptor, Dynarmic::IR::Bl
     return code_ptr;
 }
 
+void EmitX64::EmitBreakpoint(IR::Block&, IR::Inst*) {
+    code->INT3();
+}
+
 void EmitX64::EmitIdentity(IR::Block& block, IR::Inst* inst) {
     // TODO: Possible unnecessary mov here.
     reg_alloc.UseDefRegister(inst->GetArg(0), inst, any_gpr);

src/frontend/ir/ir_emitter.cpp

@@ -261,6 +261,10 @@ void IREmitter::WriteMemory64(const IR::Value& vaddr, const IR::Value& value) {
     }
 }
 
+void IREmitter::Breakpoint() {
+    Inst(IR::Opcode::Breakpoint, {});
+}
+
 void IREmitter::SetTerm(const IR::Terminal& terminal) {
     ASSERT_MSG(block.terminal.which() == 0, "Terminal has already been set.");
     block.terminal = terminal;

src/frontend/ir/ir_emitter.h

@@ -89,6 +89,8 @@ public:
     void WriteMemory32(const IR::Value& vaddr, const IR::Value& value);
     void WriteMemory64(const IR::Value& vaddr, const IR::Value& value);
 
+    void Breakpoint();
+
     void SetTerm(const IR::Terminal& terminal);
 
 private:

src/frontend/ir/opcodes.inc

@@ -1,6 +1,7 @@
 //     opcode name,             return type,    arg1 type,      arg2 type,      arg3 type,      ...
 
 OPCODE(Identity,                T::Opaque,      T::Opaque                                       )
+OPCODE(Breakpoint,              T::Void,                                                        )
 
 // ARM Context getters/setters
 OPCODE(GetRegister,             T::U32,         T::RegRef                                       )