高级语言转低级语言时访问修饰符是否保留？私有/保护成员转汇编后状态？

Great question—this gets to the heart of what access modifiers actually do under the hood. Let's break it down clearly:

First, remember that access specifiers like private, protected, and public are compile-time enforcement tools for high-level languages. Their sole job is to stop you from writing invalid code (like accessing a private class member from outside the class) before the code ever gets converted to assembly or machine code. The compiler checks these rules during compilation, and if you violate them, it throws an error and refuses to generate the low-level output.

Once the code is compiled to assembly language (or raw machine code), those access restrictions do not persist. Assembly has no concept of "private" or "protected" memory locations—every memory address is fair game if you can write the right instructions to read or write to it.

For example, say you have a C++ class with a private integer member. When compiled to assembly, that integer is just a chunk of memory at a specific offset from the class instance's base address. There's no flag or marker in the assembly that says "this is private." If someone were to hand-write assembly code that directly accesses that memory address, it would work perfectly fine—there's no runtime check stopping it.

A quick exception to note: Some languages (like Java) retain access information in their intermediate bytecode, and the JVM enforces these rules at runtime. But even then, if you compile down to native assembly (via JIT compilation), the JVM's checks are handled at the runtime level, not by any inherent restrictions in the assembly code itself.

In short: Access modifiers are guardrails for high-level code writers. Once you're in the low-level world of assembly, those guardrails are gone—all memory is effectively "public" if you know where to look.

内容的提问来源于stack exchange，提问作者prav3nom