From 940b4d1848e8c70ab7642901a68594e8016caffc Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 18:51:28 +0200 Subject: Adding upstream version 1:7.0.4. Signed-off-by: Daniel Baumann --- compilerplugins/clang/sharedvisitor/README | 45 ++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 compilerplugins/clang/sharedvisitor/README (limited to 'compilerplugins/clang/sharedvisitor/README') diff --git a/compilerplugins/clang/sharedvisitor/README b/compilerplugins/clang/sharedvisitor/README new file mode 100644 index 000000000..7b4a8b3c7 --- /dev/null +++ b/compilerplugins/clang/sharedvisitor/README @@ -0,0 +1,45 @@ +These tools generate another "plugin" which in fact only dispatches Visit* and Traverse* +calls to all other plugins registered with it. This means that there is just one +RecursiveASTVisitor pass for all those plugins instead of one per each, which +with the current number of plugins actually makes a performance difference. + +If you work on a plugin, comment out LO_CLANG_SHARED_PLUGINS in Makefile-clang.mk in order +to disable the feature (re-generating takes time). + +There are two tools: +- analyzer, which analyses one .cxx file (one plugins) and writes info about it to a .plugininfo + file, this allows parallelising this part, since it can take some time +- generator, which reads all the .plugininfo files and generates sharedvisitor.cxx + +Requirements for plugins: +- Can use Visit* and Traverse* functions, but not WalkUp*. +- Visit* functions can generally remain unmodified. +- run() function must be split into preRun() and postRun() if there's any additional functionality + besides calling TraverseDecl(). The shared visitor will call the preRun() and postRun() functions + as necessary while calling its own run(). The run() function of the plugin must stay + (in case of a non-shared build) but should generally look like this: + if( preRun()) + if( TraverseDecl(compiler.getASTContext().getTranslationUnitDecl())) + postRun(); +- Traverse* functions must be split into PreTraverse* and PostTraverse*, similarly to how run() + is handled, the Traverse* function should generally look like this: + bool ret = true; + if( PreTraverse*(decl)) + { + ret = RecursiveASTVisitor::Traverse*(decl); + PostTraverse*(decl, ret); + } + return ret; + + +TODO: +- Create macros for the standardized layout of run(), Traverse*, etc.? +- Possibly check plugin sources more thoroughly (e.g. that run() doesn't actually do more). +- Have one tool that extracts info from plugin .cxx files into some .txt file and another tool + that generates sharedvisitor.cxx based on those files? That would generally make the generation + faster when doing incremental changes. The .txt file could also contain some checksum of the .cxx + to avoid the analysing pass completely if just the timestamp has changed. +- Do not re-compile sharedvisitor.cxx if its contents have not actually changed. +- Is it possible to make the clang code analyze just the .cxx without also parsing all the headers? +- Instead of having to comment out LO_CLANG_SHARED_PLUGINS, implement --enable-compiler-plugins=debug . +- Try make analyzer use a precompiled header of Clang headers, for better performance. -- cgit v1.2.3