From d853bd7a4e86a50f7d7e6a5f397fcbd1e7d844b4 Mon Sep 17 00:00:00 2001 From: Pedro Tammela Date: Wed, 16 Dec 2020 21:34:44 +0000 Subject: [PATCH] [lldb/Lua] add support for multiline scripted breakpoints 1 - Partial Statements The interpreter loop runs every line it receives, so partial Lua statements are not being handled properly. This is a problem for multiline breakpoint scripts since the interpreter loop, for this particular case, is just an abstraction to a partially parsed function body declaration. This patch addresses this issue and as a side effect improves the general Lua interpreter loop as well. It's now possible to write partial statements in the 'script' command. Example: (lldb) script >>> do ..> local a = 123 ..> print(a) ..> end 123 The technique implemented is the same as the one employed by Lua's own REPL implementation. Partial statements always errors out with the '' tag in the error message. 2 - CheckSyntax in Lua.h In order to support (1), we need an API for just checking the syntax of string buffers. 3 - Multiline scripted breakpoints Finally, with all the base features implemented this feature is straightforward. The interpreter loop behaves exactly the same, the difference is that it will aggregate all Lua statements into the body of the breakpoint function. An explicit 'quit' statement is needed to exit the interpreter loop. Example: (lldb) breakpoint command add -s lua Enter your Lua command(s). Type 'quit' to end. The commands are compiled as the body of the following Lua function function (frame, bp_loc, ...) end ..> print(456) ..> a = 123 ..> quit Differential Revision: https://reviews.llvm.org/D93481 --- lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp | 17 ++++ lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h | 1 + .../ScriptInterpreter/Lua/ScriptInterpreterLua.cpp | 94 ++++++++++++++++++++-- .../ScriptInterpreter/Lua/ScriptInterpreterLua.h | 4 + .../ScriptInterpreter/Lua/breakpoint_callback.test | 12 ++- .../ScriptInterpreter/Lua/partial_statements.test | 15 ++++ 6 files changed, 133 insertions(+), 10 deletions(-) create mode 100644 lldb/test/Shell/ScriptInterpreter/Lua/partial_statements.test diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp b/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp index fb3628a..ec946d1 100644 --- a/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp +++ b/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.cpp @@ -105,6 +105,23 @@ Lua::CallBreakpointCallback(void *baton, lldb::StackFrameSP stop_frame_sp, bp_loc_sp); } +llvm::Error Lua::CheckSyntax(llvm::StringRef buffer) { + int error = + luaL_loadbuffer(m_lua_state, buffer.data(), buffer.size(), "buffer"); + if (error == LUA_OK) { + // Pop buffer + lua_pop(m_lua_state, 1); + return llvm::Error::success(); + } + + llvm::Error e = llvm::make_error( + llvm::formatv("{0}\n", lua_tostring(m_lua_state, -1)), + llvm::inconvertibleErrorCode()); + // Pop error message from the stack. + lua_pop(m_lua_state, 1); + return e; +} + llvm::Error Lua::LoadModule(llvm::StringRef filename) { FileSpec file(filename); if (!FileSystem::Instance().Exists(file)) { diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h b/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h index 39c39e1..84cc014 100644 --- a/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h +++ b/lldb/source/Plugins/ScriptInterpreter/Lua/Lua.h @@ -36,6 +36,7 @@ public: CallBreakpointCallback(void *baton, lldb::StackFrameSP stop_frame_sp, lldb::BreakpointLocationSP bp_loc_sp); llvm::Error LoadModule(llvm::StringRef filename); + llvm::Error CheckSyntax(llvm::StringRef buffer); llvm::Error ChangeIO(FILE *out, FILE *err); private: diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp index 239b409..1dbadb9 100644 --- a/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp +++ b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp @@ -17,23 +17,33 @@ #include "lldb/Utility/Stream.h" #include "lldb/Utility/StringList.h" #include "lldb/Utility/Timer.h" +#include "llvm/ADT/StringRef.h" #include "llvm/Support/FormatAdapters.h" #include +#include using namespace lldb; using namespace lldb_private; LLDB_PLUGIN_DEFINE(ScriptInterpreterLua) +enum ActiveIOHandler { + eIOHandlerNone, + eIOHandlerBreakpoint, + eIOHandlerWatchpoint +}; + class IOHandlerLuaInterpreter : public IOHandlerDelegate, public IOHandlerEditline { public: IOHandlerLuaInterpreter(Debugger &debugger, - ScriptInterpreterLua &script_interpreter) + ScriptInterpreterLua &script_interpreter, + ActiveIOHandler active_io_handler = eIOHandlerNone) : IOHandlerEditline(debugger, IOHandler::Type::LuaInterpreter, "lua", ">>> ", "..> ", true, debugger.GetUseColor(), 0, *this, nullptr), - m_script_interpreter(script_interpreter) { + m_script_interpreter(script_interpreter), + m_active_io_handler(active_io_handler) { llvm::cantFail(m_script_interpreter.GetLua().ChangeIO( debugger.GetOutputFile().GetStream(), debugger.GetErrorFile().GetStream())); @@ -44,20 +54,79 @@ public: llvm::cantFail(m_script_interpreter.LeaveSession()); } - void IOHandlerInputComplete(IOHandler &io_handler, - std::string &data) override { - if (llvm::StringRef(data).rtrim() == "quit") { - io_handler.SetIsDone(true); + void IOHandlerActivated(IOHandler &io_handler, bool interactive) override { + const char *instructions = nullptr; + switch (m_active_io_handler) { + case eIOHandlerNone: + case eIOHandlerWatchpoint: + break; + case eIOHandlerBreakpoint: + instructions = "Enter your Lua command(s). Type 'quit' to end.\n" + "The commands are compiled as the body of the following " + "Lua function\n" + "function (frame, bp_loc, ...) end\n"; + SetPrompt(llvm::StringRef("..> ")); + break; + } + if (instructions == nullptr) return; + if (interactive) + *io_handler.GetOutputStreamFileSP() << instructions; + } + + bool IOHandlerIsInputComplete(IOHandler &io_handler, + StringList &lines) override { + size_t last = lines.GetSize() - 1; + if (IsQuitCommand(lines.GetStringAtIndex(last))) { + if (m_active_io_handler == eIOHandlerBreakpoint) + lines.DeleteStringAtIndex(last); + return true; + } + StreamString str; + lines.Join("\n", str); + if (llvm::Error E = + m_script_interpreter.GetLua().CheckSyntax(str.GetString())) { + std::string error_str = toString(std::move(E)); + // Lua always errors out to incomplete code with '' + return error_str.find("") == std::string::npos; } + // The breakpoint handler only exits with a explicit 'quit' + return m_active_io_handler != eIOHandlerBreakpoint; + } - if (llvm::Error error = m_script_interpreter.GetLua().Run(data)) { - *GetOutputStreamFileSP() << llvm::toString(std::move(error)); + void IOHandlerInputComplete(IOHandler &io_handler, + std::string &data) override { + switch (m_active_io_handler) { + case eIOHandlerBreakpoint: { + auto *bp_options_vec = static_cast *>( + io_handler.GetUserData()); + for (auto *bp_options : *bp_options_vec) { + Status error = m_script_interpreter.SetBreakpointCommandCallback( + bp_options, data.c_str()); + if (error.Fail()) + *io_handler.GetErrorStreamFileSP() << error.AsCString() << '\n'; + } + io_handler.SetIsDone(true); + } break; + case eIOHandlerWatchpoint: + io_handler.SetIsDone(true); + break; + case eIOHandlerNone: + if (IsQuitCommand(data)) { + io_handler.SetIsDone(true); + return; + } + if (llvm::Error error = m_script_interpreter.GetLua().Run(data)) + *io_handler.GetErrorStreamFileSP() << toString(std::move(error)); + break; } } private: ScriptInterpreterLua &m_script_interpreter; + ActiveIOHandler m_active_io_handler; + + bool IsQuitCommand(llvm::StringRef cmd) { return cmd.rtrim() == "quit"; } }; ScriptInterpreterLua::ScriptInterpreterLua(Debugger &debugger) @@ -205,6 +274,15 @@ bool ScriptInterpreterLua::BreakpointCallbackFunction( return *BoolOrErr; } +void ScriptInterpreterLua::CollectDataForBreakpointCommandCallback( + std::vector &bp_options_vec, + CommandReturnObject &result) { + IOHandlerSP io_handler_sp( + new IOHandlerLuaInterpreter(m_debugger, *this, eIOHandlerBreakpoint)); + io_handler_sp->SetUserData(&bp_options_vec); + m_debugger.RunIOHandlerAsync(io_handler_sp); +} + Status ScriptInterpreterLua::SetBreakpointCommandCallback( BreakpointOptions *bp_options, const char *command_body_text) { Status error; diff --git a/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h index 1238b89..6c3fc01 100644 --- a/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h +++ b/lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.h @@ -65,6 +65,10 @@ public: llvm::Error EnterSession(lldb::user_id_t debugger_id); llvm::Error LeaveSession(); + void CollectDataForBreakpointCommandCallback( + std::vector &bp_options_vec, + CommandReturnObject &result) override; + Status SetBreakpointCommandCallback(BreakpointOptions *bp_options, const char *command_body_text) override; diff --git a/lldb/test/Shell/ScriptInterpreter/Lua/breakpoint_callback.test b/lldb/test/Shell/ScriptInterpreter/Lua/breakpoint_callback.test index 4dbf286..65997d8 100644 --- a/lldb/test/Shell/ScriptInterpreter/Lua/breakpoint_callback.test +++ b/lldb/test/Shell/ScriptInterpreter/Lua/breakpoint_callback.test @@ -1,5 +1,13 @@ # REQUIRES: lua -# RUN: %lldb -s %s --script-language lua 2>&1 | FileCheck %s +# RUN: echo "int main() { return 0; }" | %clang_host -x c - -o %t +# RUN: %lldb -s %s --script-language lua %t 2>&1 | FileCheck %s b main breakpoint command add -s lua -# CHECK: error: This script interpreter does not support breakpoint callbacks +local a = 123 +print(a) +quit +run +# CHECK: 123 +breakpoint command add -s lua +789_nil +# CHECK: unexpected symbol near '789' diff --git a/lldb/test/Shell/ScriptInterpreter/Lua/partial_statements.test b/lldb/test/Shell/ScriptInterpreter/Lua/partial_statements.test new file mode 100644 index 0000000..3b764d7 --- /dev/null +++ b/lldb/test/Shell/ScriptInterpreter/Lua/partial_statements.test @@ -0,0 +1,15 @@ +# REQUIRES: lua +# RUN: %lldb -s %s --script-language lua 2>&1 | FileCheck %s +script +do +local a = 123 +print(a) +end +# CHECK: 123 +str = 'hello there!' +function callme() +print(str) +end +callme() +# CHECK: hello there! +# CHECK-NOT: error -- 2.7.4