<div dir="ltr"><div dir="ltr">On Tue, Jun 2, 2020 at 10:38 AM Kadir Çetinkaya <<a href="mailto:kadircet@google.com">kadircet@google.com</a>> wrote:<br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi Jan,<div><br></div><div>I don't think there's much point in running ReplayPreamble with an empty preamble, but this should already be a no-op as there can't be any includes inside the preamble region if size is 0.</div><div><br></div><div>I can't seem to reproduce a failure with the root causes you've provided. Even when ReplayPreamble::create doesn't take the early exit, for an empty preamble we should not have any includes, hence ReplayPreamble::replay would be a no-op. That's what I am getting while running the tests (you can check this by printing the MainFileIncludes in ReplayPreamble::create before early exit. Note that PatchesAdditionalIncludes builds two ASTs, the first one will have additional includes as it builds a full AST with a non-empty preamble, but the second AST should be built with an empty preamble and empty preamble-includes)</div></div></blockquote><div>Yeah, this sounds suspicious to me.</div><div>In that loop just before the failed assert, can you dump the details of `Inc`?</div><div>Specifically `Written`, `Resolved`, and HashOffset, and ideally work out what buffer HashOffset really indexes into.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><br></div><div>It seems like something else is going on here, any chance you are inserting an implicit include inside your custom PP logic? If that's the case we should look for a fix in include extraction logic as it shouldn't pick up includes that are coming from implicit(more over non-main-file) sources.</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jun 2, 2020 at 8:09 AM Jan Korous via Phabricator <<a href="mailto:reviews@reviews.llvm.org" target="_blank">reviews@reviews.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">jkorous added a comment.<br>
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Hi @kadircet!<br>
I am investigating a failure of `PatchesAdditionalIncludes` test that we got internally. It's a failed assert in `ReplayPreamble::replay`.<br>
Our clangd source code is for all practical purposes identical to upstream version but not so with clang source. Specifically what we do is that in `CompilerInstance::createPreprocessor` we always add one particular callback.<br>
This means that when in the test we are calling `buildPreamble` for `TestTU TU` with empty buffer we never hit the early return in `ReplayPreamble::attach()` (ParsedAST.cpp:124) like upstream version does and proceed to create a new `ReplayPreamble` object with `PreambleBounds` of `size() == 0` which leads to `ReplayPreamble::MainFileTokens` to be empty and later we hit failed assert in `ReplayPreamble::replay` about `assert(HashTok != MainFileTokens.end() && ...)`.<br>
<br>
Now, while I can just tweak either `ReplayPreamble::attach()` or remove the PP callback in the test internally I am wondering whether you consider empty preamble & PP with callbacks valid use-case of `ReplayPreamble` and worth a fix.<br>
<br>
This is where we are creating the empty `MainFileTokens`:<br>
<br>
* frame #0: 0x0000000103337649 ClangdTests` clang::clangd::(anonymous namespace)::ReplayPreamble::ReplayPreamble(this=0x0000000114f45da0, Includes=0x00007ffeefbfc678, Delegate=0x0000000114f3bd80, SM=0x0000000114f3dd80, PP=0x0000000115850218, LangOpts=0x0000000114f38eb0, PB=0x00007ffeefbfc658) + 169 at ParsedAST.cpp:142<br>
frame #1: 0x000000010333756d ClangdTests` clang::clangd::(anonymous namespace)::ReplayPreamble::ReplayPreamble(this=0x0000000114f45da0, Includes=0x00007ffeefbfc678, Delegate=0x0000000114f3bd80, SM=0x0000000114f3dd80, PP=0x0000000115850218, LangOpts=0x0000000114f38eb0, PB=0x00007ffeefbfc658) + 77 at ParsedAST.cpp:139<br>
frame #2: 0x0000000103334fa7 ClangdTests` clang::clangd::(anonymous namespace)::ReplayPreamble::attach(Includes=0x00007ffeefbfc678, Clang=0x0000000114f33ea0, PB=0x00007ffeefbfc658) + 183 at ParsedAST.cpp:126<br>
frame #3: 0x0000000103334189 ClangdTests` clang::clangd::ParsedAST::build(Filename=(Data = "/clangd-test/foo.cpp", Length = 20), Inputs=0x00007ffeefbfdf98, CI=nullptr, CompilerInvocationDiags=ArrayRef<clang::clangd::Diag> @ 0x00007ffeefbfd830, Preamble=std::__1::shared_ptr<const clang::clangd::PreambleData>::element_type @ 0x0000000114f3e728 strong=2 weak=1) + 3897 at ParsedAST.cpp:385<br>
frame #4: 0x00000001006f1032 ClangdTests` clang::clangd::(anonymous namespace)::ParsedASTTest_PatchesAdditionalIncludes_Test::TestBody(this=0x0000000114f04090) + 1778 at ParsedASTTests.cpp:477<br>
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This is the failed assert:<br>
<br>
* frame #4: 0x0000000103337a0c ClangdTests` clang::clangd::(anonymous namespace)::ReplayPreamble::replay(this=0x0000000114f45da0) + 556 at ParsedAST.cpp:182<br>
frame #5: 0x000000010333777c ClangdTests` clang::clangd::(anonymous namespace)::ReplayPreamble::FileChanged(this=0x0000000114f45da0, Loc=(ID = 74), Reason=ExitFile, Kind=C_User, PrevFID=(ID = 2)) + 156 at ParsedAST.cpp:166<br>
frame #6: 0x0000000101b7900a ClangdTests` clang::PPChainedCallbacks::FileChanged(this=0x0000000116204080, Loc=(ID = 74), Reason=ExitFile, FileType=C_User, PrevFID=(ID = 2)) + 90 at PPCallbacks.h:390<br>
frame #7: 0x0000000101b79046 ClangdTests` clang::PPChainedCallbacks::FileChanged(this=0x00000001162040c0, Loc=(ID = 74), Reason=ExitFile, FileType=C_User, PrevFID=(ID = 2)) + 150 at PPCallbacks.h:391<br>
frame #8: 0x0000000101b79046 ClangdTests` clang::PPChainedCallbacks::FileChanged(this=0x0000000116204100, Loc=(ID = 74), Reason=ExitFile, FileType=C_User, PrevFID=(ID = 2)) + 150 at PPCallbacks.h:391<br>
frame #9: 0x0000000101b79046 ClangdTests` clang::PPChainedCallbacks::FileChanged(this=0x0000000116204160, Loc=(ID = 74), Reason=ExitFile, FileType=C_User, PrevFID=(ID = 2)) + 150 at PPCallbacks.h:391<br>
frame #10: 0x0000000101b79046 ClangdTests` clang::PPChainedCallbacks::FileChanged(this=0x0000000116205480, Loc=(ID = 74), Reason=ExitFile, FileType=C_User, PrevFID=(ID = 2)) + 150 at PPCallbacks.h:391<br>
frame #11: 0x0000000101b9a590 ClangdTests` clang::Preprocessor::HandleEndOfFile(this=0x0000000115850218, Result=0x0000000116808210, isEndOfMacro=false) + 3904 at PPLexerChange.cpp:469<br>
frame #12: 0x0000000101b38713 ClangdTests` clang::Lexer::LexEndOfFile(this=0x0000000116206330, Result=0x0000000116808210, CurPtr="") + 931 at Lexer.cpp:2833<br>
frame #13: 0x0000000101b39c44 ClangdTests` clang::Lexer::LexTokenInternal(this=0x0000000116206330, Result=0x0000000116808210, TokAtPhysicalStartOfLine=true) + 420 at Lexer.cpp:3265<br>
frame #14: 0x0000000101b382f8 ClangdTests` clang::Lexer::Lex(this=0x0000000116206330, Result=0x0000000116808210) + 216 at Lexer.cpp:3216<br>
frame #15: 0x0000000101bd7396 ClangdTests` clang::Preprocessor::Lex(this=0x0000000115850218, Result=0x0000000116808210) + 118 at Preprocessor.cpp:900<br>
frame #16: 0x0000000101b75ef1 ClangdTests` clang::Preprocessor::CachingLex(this=0x0000000115850218, Result=0x0000000116808210) + 289 at PPCaching.cpp:63<br>
frame #17: 0x0000000101bd73d5 ClangdTests` clang::Preprocessor::Lex(this=0x0000000115850218, Result=0x0000000116808210) + 181 at Preprocessor.cpp:906<br>
frame #18: 0x0000000104e3c21c ClangdTests` clang::Parser::TryConsumeToken(this=0x0000000116808200, Expected=semi) + 204 at Parser.h:489<br>
frame #19: 0x0000000104e3bf1a ClangdTests` clang::Parser::ExpectAndConsumeSemi(this=0x0000000116808200, DiagID=1526) + 42 at Parser.cpp:162<br>
frame #20: 0x0000000104d5f0e0 ClangdTests` clang::Parser::ParseDeclGroup(this=0x0000000116808200, DS=0x00007ffeefbfb6e8, Context=FileContext, DeclEnd=0x0000000000000000, FRI=0x0000000000000000) + 3168 at ParseDecl.cpp:2243<br>
frame #21: 0x0000000104e42c48 ClangdTests` clang::Parser::ParseDeclOrFunctionDefInternal(this=0x0000000116808200, attrs=0x00007ffeefbfbc80, DS=0x00007ffeefbfb6e8, AS=AS_none) + 1704 at Parser.cpp:1109<br>
frame #22: 0x0000000104e42170 ClangdTests` clang::Parser::ParseDeclarationOrFunctionDefinition(this=0x0000000116808200, attrs=0x00007ffeefbfbc80, DS=0x0000000000000000, AS=AS_none) + 144 at Parser.cpp:1125<br>
frame #23: 0x0000000104e411fa ClangdTests` clang::Parser::ParseExternalDeclaration(this=0x0000000116808200, attrs=0x00007ffeefbfbc80, DS=0x0000000000000000) + 3642 at Parser.cpp:945<br>
frame #24: 0x0000000104e3f254 ClangdTests` clang::Parser::ParseTopLevelDecl(this=0x0000000116808200, Result=0x00007ffeefbfbde8, IsFirstDecl=false) + 1828 at Parser.cpp:693<br>
frame #25: 0x0000000104d465e3 ClangdTests` clang::ParseAST(S=0x000000011680c200, PrintStats=false, SkipFunctionBodies=false) + 595 at ParseAST.cpp:158<br>
frame #26: 0x0000000101992662 ClangdTests` clang::ASTFrontendAction::ExecuteAction(this=0x0000000114f349a0) + 322 at FrontendAction.cpp:1066<br>
frame #27: 0x0000000101991b78 ClangdTests` clang::FrontendAction::Execute(this=0x0000000114f349a0) + 136 at FrontendAction.cpp:959<br>
frame #28: 0x00000001033343ab ClangdTests` clang::clangd::ParsedAST::build(Filename=(Data = "/clangd-test/foo.cpp", Length = 20), Inputs=0x00007ffeefbfdf98, CI=nullptr, CompilerInvocationDiags=ArrayRef<clang::clangd::Diag> @ 0x00007ffeefbfd830, Preamble=std::__1::shared_ptr<const clang::clangd::PreambleData>::element_type @ 0x0000000114f3e728 strong=2 weak=1) + 4443 at ParsedAST.cpp:415<br>
frame #29: 0x00000001006f1032 ClangdTests` clang::clangd::(anonymous namespace)::ParsedASTTest_PatchesAdditionalIncludes_Test::TestBody(this=0x0000000114f04090) + 1778 at ParsedASTTests.cpp:477<br>
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Repository:<br>
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