================ @@ -8,470 +8,966 @@ Debugging C++ Coroutines Introduction ============ -For performance and other architectural reasons, the C++ Coroutines feature in -the Clang compiler is implemented in two parts of the compiler. Semantic -analysis is performed in Clang, and Coroutine construction and optimization -takes place in the LLVM middle-end. +Coroutines in C++ were introduced in C++20, and the user experience for +debugging them can still be challenging. This document guides you how to most +efficiently debug coroutines and how to navigate existing shortcomings in +debuggers and compilers. + +Coroutines are generally used either as generators or for asynchronous +programming. In this document, we will discuss both use cases. Even if you are +using coroutines for asynchronous programming, you should still read the +generators section, as it will introduce foundational debugging techniques also +applicable to the debugging of asynchronous programming. + +Both compilers (clang, gcc, ...) and debuggers (lldb, gdb, ...) are +still improving their support for coroutines. As such, we recommend using the +latest available version of your toolchain. + +This document focuses on clang and lldb. The screenshots show +[lldb-dap](https://marketplace.visualstudio.com/items?itemName=llvm-vs-code-extensions.lldb-dap) +in combination with VS Code. The same techniques can also be used in other +IDEs. + +Debugging clang-compiled binaries with gdb is possible, but requires more +scripting. This guide comes with a basic GDB script for coroutine debugging. + +This guide will first showcase the more polished, bleeding-edge experience, but +will also show you how to debug coroutines with older toolchains. In general, +the older your toolchain, the deeper you will have to dive into the +implementation details of coroutines (such as their ABI). The further down in +this document you go, the more low-level, technical the content will become. If +you are on an up-to-date toolchain, you will hopefully be able to stop reading +earlier. + +Debugging generators +==================== + +The first major use case for coroutines in C++ are generators, i.e., functions ---------------- ChuanqiXu9 wrote:
it sounds better https://github.com/llvm/llvm-project/pull/142651 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
