From 5b3284a9275a27f5c4410e25eb8933be540601d6 Mon Sep 17 00:00:00 2001 From: Argyrios Kyrtzidis Date: Wed, 29 Jun 2011 22:20:11 +0000 Subject: [PATCH] Introduce a caching mechanism for macro expanded tokens. Previously macro expanded tokens were added to Preprocessor's bump allocator and never released, even after the TokenLexer that were lexing them was finished, thus they were wasting memory. A very "useful" boost library was causing clang to eat 1 GB just for the expanded macro tokens. Introduce a special cache that works like a stack; a TokenLexer can add the macro expanded tokens in the cache, and when it finishes, the tokens are removed from the end of the cache. Now consumed memory by expanded tokens for that library is ~ 1.5 MB. Part of rdar://9327049. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134105 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/clang/Lex/Preprocessor.h | 19 +++++++++++++++ include/clang/Lex/TokenLexer.h | 9 ++++--- lib/Lex/PPLexerChange.cpp | 4 ++++ lib/Lex/PPMacroExpansion.cpp | 41 ++++++++++++++++++++++++++++++++ lib/Lex/Preprocessor.cpp | 4 +++- lib/Lex/TokenLexer.cpp | 12 ++++------ 6 files changed, 77 insertions(+), 12 deletions(-) diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h index abba959dee..56fc9d1727 100644 --- a/include/clang/Lex/Preprocessor.h +++ b/include/clang/Lex/Preprocessor.h @@ -29,6 +29,7 @@ #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/OwningPtr.h" #include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/ArrayRef.h" #include "llvm/Support/Allocator.h" #include @@ -240,6 +241,14 @@ class Preprocessor : public llvm::RefCountedBase { unsigned NumCachedTokenLexers; TokenLexer *TokenLexerCache[TokenLexerCacheSize]; + /// \brief Keeps macro expanded tokens for TokenLexers. + // + /// Works like a stack; a TokenLexer adds the macro expanded tokens that is + /// going to lex in the cache and when it finishes the tokens are removed + /// from the end of the cache. + llvm::SmallVector MacroExpandedTokens; + std::vector > MacroExpandingLexersStack; + /// \brief A record of the macro definitions and instantiations that /// occurred during preprocessing. /// @@ -979,6 +988,16 @@ private: /// the macro should not be expanded return true, otherwise return false. bool HandleMacroExpandedIdentifier(Token &Tok, MacroInfo *MI); + /// \brief Cache macro expanded tokens for TokenLexers. + // + /// Works like a stack; a TokenLexer adds the macro expanded tokens that is + /// going to lex in the cache and when it finishes the tokens are removed + /// from the end of the cache. + Token *cacheMacroExpandedTokens(TokenLexer *tokLexer, + llvm::ArrayRef tokens); + void removeCachedMacroExpandedTokensOfLastLexer(); + friend void TokenLexer::ExpandFunctionArguments(); + /// isNextPPTokenLParen - Determine whether the next preprocessor token to be /// lexed is a '('. If so, consume the token and return true, if not, this /// method should have no observable side-effect on the lexed tokens. diff --git a/include/clang/Lex/TokenLexer.h b/include/clang/Lex/TokenLexer.h index 6ae00cd586..8f530053ca 100644 --- a/include/clang/Lex/TokenLexer.h +++ b/include/clang/Lex/TokenLexer.h @@ -43,10 +43,13 @@ class TokenLexer { /// Tokens - This is the pointer to an array of tokens that the macro is /// defined to, with arguments expanded for function-like macros. If this is /// a token stream, these are the tokens we are returning. This points into - /// the macro definition we are lexing from, a scratch buffer allocated from - /// the preprocessor's bump pointer allocator, or some other buffer that we - /// may or may not own (depending on OwnsTokens). + /// the macro definition we are lexing from, a cache buffer that is owned by + /// the preprocessor, or some other buffer that we may or may not own + /// (depending on OwnsTokens). + /// Note that if it points into Preprocessor's cache buffer, the Preprocessor + /// may update the pointer as needed. const Token *Tokens; + friend class Preprocessor; /// NumTokens - This is the length of the Tokens array. /// diff --git a/lib/Lex/PPLexerChange.cpp b/lib/Lex/PPLexerChange.cpp index bf0a7fbfef..bf28199b88 100644 --- a/lib/Lex/PPLexerChange.cpp +++ b/lib/Lex/PPLexerChange.cpp @@ -265,6 +265,10 @@ bool Preprocessor::HandleEndOfTokenLexer(Token &Result) { assert(CurTokenLexer && !CurPPLexer && "Ending a macro when currently in a #include file!"); + if (!MacroExpandingLexersStack.empty() && + MacroExpandingLexersStack.back().first == CurTokenLexer.get()) + removeCachedMacroExpandedTokensOfLastLexer(); + // Delete or cache the now-dead macro expander. if (NumCachedTokenLexers == TokenLexerCacheSize) CurTokenLexer.reset(); diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp index 9e8533a448..d7c4defb36 100644 --- a/lib/Lex/PPMacroExpansion.cpp +++ b/lib/Lex/PPMacroExpansion.cpp @@ -22,6 +22,7 @@ #include "clang/Lex/CodeCompletionHandler.h" #include "clang/Lex/ExternalPreprocessorSource.h" #include "llvm/ADT/StringSwitch.h" +#include "llvm/ADT/STLExtras.h" #include "llvm/Config/config.h" #include "llvm/Support/raw_ostream.h" #include @@ -490,6 +491,46 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName, isVarargsElided, *this); } +/// \brief Keeps macro expanded tokens for TokenLexers. +// +/// Works like a stack; a TokenLexer adds the macro expanded tokens that is +/// going to lex in the cache and when it finishes the tokens are removed +/// from the end of the cache. +Token *Preprocessor::cacheMacroExpandedTokens(TokenLexer *tokLexer, + llvm::ArrayRef tokens) { + assert(tokLexer); + if (tokens.empty()) + return 0; + + size_t newIndex = MacroExpandedTokens.size(); + bool cacheNeedsToGrow = tokens.size() > + MacroExpandedTokens.capacity()-MacroExpandedTokens.size(); + MacroExpandedTokens.append(tokens.begin(), tokens.end()); + + if (cacheNeedsToGrow) { + // Go through all the TokenLexers whose 'Tokens' pointer points in the + // buffer and update the pointers to the (potential) new buffer array. + for (unsigned i = 0, e = MacroExpandingLexersStack.size(); i != e; ++i) { + TokenLexer *prevLexer; + size_t tokIndex; + llvm::tie(prevLexer, tokIndex) = MacroExpandingLexersStack[i]; + prevLexer->Tokens = MacroExpandedTokens.data() + tokIndex; + } + } + + MacroExpandingLexersStack.push_back(std::make_pair(tokLexer, newIndex)); + return MacroExpandedTokens.data() + newIndex; +} + +void Preprocessor::removeCachedMacroExpandedTokensOfLastLexer() { + assert(!MacroExpandingLexersStack.empty()); + size_t tokIndex = MacroExpandingLexersStack.back().second; + assert(tokIndex < MacroExpandedTokens.size()); + // Pop the cached macro expanded tokens from the end. + MacroExpandedTokens.resize(tokIndex); + MacroExpandingLexersStack.pop_back(); +} + /// ComputeDATE_TIME - Compute the current time, enter it into the specified /// scratch buffer, then return DATELoc/TIMELoc locations with the position of /// the identifier tokens inserted. diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp index 48a23880f3..2f43c8e30b 100644 --- a/lib/Lex/Preprocessor.cpp +++ b/lib/Lex/Preprocessor.cpp @@ -118,6 +118,8 @@ Preprocessor::Preprocessor(Diagnostic &diags, const LangOptions &opts, Preprocessor::~Preprocessor() { assert(BacktrackPositions.empty() && "EnableBacktrack/Backtrack imbalance!"); + assert(MacroExpandingLexersStack.empty() && MacroExpandedTokens.empty() && + "Preprocessor::HandleEndOfTokenLexer should have cleared those"); while (!IncludeMacroStack.empty()) { delete IncludeMacroStack.back().TheLexer; @@ -226,7 +228,7 @@ Preprocessor::macro_begin(bool IncludeExternalMacros) const { } size_t Preprocessor::getTotalMemory() const { - return BP.getTotalMemory(); + return BP.getTotalMemory() + MacroExpandedTokens.capacity()*sizeof(Token); } Preprocessor::macro_iterator diff --git a/lib/Lex/TokenLexer.cpp b/lib/Lex/TokenLexer.cpp index e7cff8bdc3..f30c44e0e6 100644 --- a/lib/Lex/TokenLexer.cpp +++ b/lib/Lex/TokenLexer.cpp @@ -284,15 +284,11 @@ void TokenLexer::ExpandFunctionArguments() { assert(!OwnsTokens && "This would leak if we already own the token list"); // This is deleted in the dtor. NumTokens = ResultToks.size(); - llvm::BumpPtrAllocator &Alloc = PP.getPreprocessorAllocator(); - Token *Res = - static_cast(Alloc.Allocate(sizeof(Token)*ResultToks.size(), - llvm::alignOf())); - if (NumTokens) - memcpy(Res, &ResultToks[0], NumTokens*sizeof(Token)); - Tokens = Res; + // The tokens will be added to Preprocessor's cache and will be removed + // when this TokenLexer finishes lexing them. + Tokens = PP.cacheMacroExpandedTokens(this, ResultToks); - // The preprocessor bump pointer owns these tokens, not us. + // The preprocessor cache of macro expanded tokens owns these tokens,not us. OwnsTokens = false; } }