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Diffstat (limited to '')
| -rw-r--r-- | compilerplugins/clang/methodcycles.cxx | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/compilerplugins/clang/methodcycles.cxx b/compilerplugins/clang/methodcycles.cxx new file mode 100644 index 000000000..7b58a4bb5 --- /dev/null +++ b/compilerplugins/clang/methodcycles.cxx @@ -0,0 +1,378 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#include <cassert> +#include <string> +#include <iostream> +#include <fstream> +#include <set> +#include <unordered_set> +#include <map> + +#include "clang/AST/Attr.h" + +#include "config_clang.h" + +#include "plugin.hxx" + +/** +What we are looking for here are methods that are not reachable from any of the program +entry points. +"Entry points" includes main, and various binary API + +Mostly that means we end up finding cycles of methods i.e. methods that refer to each +other, but are not reachable. + +It does so, by dumping various call/definition info to a log file. +Be warned that it produces around 20G of log file. + +Then we will post-process the log file with a python script, which takes about +15min to run on a fast machine. + +The process goes something like this: + $ make check + $ make FORCE_COMPILE=all COMPILER_PLUGIN_TOOL='methodcycles' check + $ ./compilerplugins/clang/methodcycles.py + +Note that the actual process may involve a fair amount of undoing, hand editing, and general messing around +to get it to work :-) + +*/ + +namespace +{ +struct MyFuncInfo +{ + std::string returnType; + std::string nameAndParams; + std::string sourceLocation; +}; +bool operator<(const MyFuncInfo& lhs, const MyFuncInfo& rhs) +{ + return std::tie(lhs.returnType, lhs.nameAndParams) + < std::tie(rhs.returnType, rhs.nameAndParams); +} + +// try to limit the voluminous output a little +static std::multimap<const FunctionDecl*, const FunctionDecl*> callMap; +static std::set<MyFuncInfo> definitionSet; + +class MethodCycles : public RecursiveASTVisitor<MethodCycles>, public loplugin::Plugin +{ +public: + explicit MethodCycles(loplugin::InstantiationData const& data) + : Plugin(data) + { + } + + virtual void run() override + { + TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); + + // dump all our output in one write call - this is to try and limit IO "crosstalk" between multiple processes + // writing to the same logfile + + std::string output; + for (const MyFuncInfo& s : definitionSet) + output += "definition:\t" + s.returnType + "\t" + s.nameAndParams + "\t" + + s.sourceLocation + "\n"; + for (const auto& pair : callMap) + { + if (!isLocationMine(pair.first->getLocation()) + || !isLocationMine(pair.second->getLocation())) + continue; + auto niceNameFrom = niceName(pair.first); + auto niceNameTo = niceName(pair.second); + output += "call:\t" + niceNameFrom.returnType + "\t" + niceNameFrom.nameAndParams + "\t" + + niceNameTo.returnType + "\t" + niceNameTo.nameAndParams + "\n"; + } + std::ofstream myfile; + myfile.open(WORKDIR "/loplugin.methodcycles.log", std::ios::app | std::ios::out); + myfile << output; + myfile.close(); + } + + bool shouldVisitTemplateInstantiations() const { return true; } + bool shouldVisitImplicitCode() const { return true; } + + bool VisitCallExpr(CallExpr*); + bool VisitFunctionDecl(const FunctionDecl* decl); + bool VisitDeclRefExpr(const DeclRefExpr*); + bool VisitCXXConstructExpr(const CXXConstructExpr*); + + bool TraverseFunctionDecl(FunctionDecl*); + bool TraverseCXXMethodDecl(CXXMethodDecl*); + bool TraverseCXXConstructorDecl(CXXConstructorDecl*); + bool TraverseCXXConversionDecl(CXXConversionDecl*); + bool TraverseCXXDestructorDecl(CXXDestructorDecl*); + bool TraverseCXXDeductionGuideDecl(CXXDeductionGuideDecl*); + +private: + void logCallToRootMethods(const FunctionDecl* functionDeclFrom, + const FunctionDecl* functionDeclTo); + void findRoots(const FunctionDecl* functionDecl, + std::unordered_set<const FunctionDecl*>& roots); + MyFuncInfo niceName(const FunctionDecl* functionDecl); + bool isLocationMine(SourceLocation loc); + std::string toString(SourceLocation loc); + FunctionDecl const* currentFunctionDecl = nullptr; +}; + +MyFuncInfo MethodCycles::niceName(const FunctionDecl* functionDecl) +{ + if (functionDecl->getInstantiatedFromMemberFunction()) + functionDecl = functionDecl->getInstantiatedFromMemberFunction(); + else if (functionDecl->getTemplateInstantiationPattern()) + functionDecl = functionDecl->getTemplateInstantiationPattern(); + + MyFuncInfo aInfo; + if (!isa<CXXConstructorDecl>(functionDecl)) + { + aInfo.returnType = functionDecl->getReturnType().getCanonicalType().getAsString(); + } + else + { + aInfo.returnType = ""; + } + + if (auto methodDecl = dyn_cast<CXXMethodDecl>(functionDecl)) + { + const CXXRecordDecl* recordDecl = methodDecl->getParent(); + aInfo.nameAndParams + = recordDecl->getQualifiedNameAsString() + "::" + functionDecl->getNameAsString() + "("; + } + else + { + aInfo.nameAndParams = functionDecl->getQualifiedNameAsString() + "("; + } + bool bFirst = true; + for (const ParmVarDecl* pParmVarDecl : functionDecl->parameters()) + { + if (bFirst) + bFirst = false; + else + aInfo.nameAndParams += ","; + aInfo.nameAndParams += pParmVarDecl->getType().getCanonicalType().getAsString(); + } + aInfo.nameAndParams += ")"; + if (isa<CXXMethodDecl>(functionDecl) && dyn_cast<CXXMethodDecl>(functionDecl)->isConst()) + { + aInfo.nameAndParams += " const"; + } + + aInfo.sourceLocation = toString(functionDecl->getLocation()); + + return aInfo; +} + +std::string MethodCycles::toString(SourceLocation loc) +{ + SourceLocation expansionLoc = compiler.getSourceManager().getExpansionLoc(loc); + StringRef name = getFilenameOfLocation(expansionLoc); + std::string sourceLocation + = std::string(name.substr(strlen(SRCDIR) + 1)) + ":" + + std::to_string(compiler.getSourceManager().getSpellingLineNumber(expansionLoc)); + loplugin::normalizeDotDotInFilePath(sourceLocation); + return sourceLocation; +} + +bool MethodCycles::isLocationMine(SourceLocation loc) +{ + SourceLocation expansionLoc = compiler.getSourceManager().getExpansionLoc(loc); + if (compiler.getSourceManager().isInSystemHeader(expansionLoc)) + return false; + const char* bufferName = compiler.getSourceManager().getPresumedLoc(expansionLoc).getFilename(); + if (bufferName == NULL) + return false; + if (loplugin::hasPathnamePrefix(bufferName, WORKDIR "/") + || loplugin::hasPathnamePrefix(bufferName, BUILDDIR "/") + || loplugin::hasPathnamePrefix(bufferName, SRCDIR "/")) + return true; // ok + return false; +} + +void MethodCycles::logCallToRootMethods(const FunctionDecl* functionDeclFrom, + const FunctionDecl* functionDeclTo) +{ + if (!functionDeclFrom) + { + // template magic mostly, but also things called from initialisers + return; + } + functionDeclFrom = functionDeclFrom->getCanonicalDecl(); + functionDeclTo = functionDeclTo->getCanonicalDecl(); + + std::unordered_set<const FunctionDecl*> fromRoots; + findRoots(functionDeclFrom, fromRoots); + std::unordered_set<const FunctionDecl*> toRoots; + findRoots(functionDeclTo, toRoots); + + for (auto const& from : fromRoots) + for (auto const& to : toRoots) + callMap.insert({ from, to }); +} + +void MethodCycles::findRoots(const FunctionDecl* functionDecl, + std::unordered_set<const FunctionDecl*>& roots) +{ + bool bCalledSuperMethod = false; + if (auto methodDecl = dyn_cast<CXXMethodDecl>(functionDecl)) + { + // For virtual/overriding methods, we need to pretend we called from/to root method(s), + // so that they get marked as used. + for (auto it = methodDecl->begin_overridden_methods(); + it != methodDecl->end_overridden_methods(); ++it) + { + findRoots(*it, roots); + bCalledSuperMethod = true; + } + } + if (!bCalledSuperMethod) + { + while (functionDecl->getTemplateInstantiationPattern()) + functionDecl = functionDecl->getTemplateInstantiationPattern(); + if (functionDecl->getLocation().isValid()) + roots.insert(functionDecl); + } +} + +bool MethodCycles::VisitCallExpr(CallExpr* expr) +{ + // Note that I don't ignore ANYTHING here, because I want to get calls to my code that result + // from template instantiation deep inside the STL and other external code + + FunctionDecl* calleeFunctionDecl = expr->getDirectCallee(); + if (calleeFunctionDecl == nullptr) + { + Expr* callee = expr->getCallee()->IgnoreParenImpCasts(); + DeclRefExpr* dr = dyn_cast<DeclRefExpr>(callee); + if (dr) + { + calleeFunctionDecl = dyn_cast<FunctionDecl>(dr->getDecl()); + if (calleeFunctionDecl) + goto gotfunc; + } + return true; + } + +gotfunc: + + if (currentFunctionDecl != calleeFunctionDecl) + // ignore recursive calls + logCallToRootMethods(currentFunctionDecl, calleeFunctionDecl); + + return true; +} + +bool MethodCycles::VisitCXXConstructExpr(const CXXConstructExpr* constructExpr) +{ + // Note that I don't ignore ANYTHING here, because I want to get calls to my code that result + // from template instantiation deep inside the STL and other external code + + const CXXConstructorDecl* constructorDecl = constructExpr->getConstructor(); + constructorDecl = constructorDecl->getCanonicalDecl(); + + if (!constructorDecl->getLocation().isValid()) + { + return true; + } + + logCallToRootMethods(currentFunctionDecl, constructorDecl); + + return true; +} + +bool MethodCycles::VisitFunctionDecl(const FunctionDecl* functionDecl) +{ + const FunctionDecl* canonicalFunctionDecl = functionDecl->getCanonicalDecl(); + if (functionDecl->isDeleted()) + return true; + // don't care about compiler-generated functions + if (functionDecl->isImplicit()) + return true; + if (!canonicalFunctionDecl->getLocation().isValid()) + return true; + // ignore method overrides, since the call will show up as being directed to the root method + const CXXMethodDecl* methodDecl = dyn_cast<CXXMethodDecl>(functionDecl); + if (methodDecl + && (methodDecl->size_overridden_methods() != 0 || methodDecl->hasAttr<OverrideAttr>())) + return true; + if (!isLocationMine(canonicalFunctionDecl->getLocation())) + return true; + + MyFuncInfo funcInfo = niceName(canonicalFunctionDecl); + definitionSet.insert(funcInfo); + return true; +} + +bool MethodCycles::VisitDeclRefExpr(const DeclRefExpr* declRefExpr) +{ + const FunctionDecl* functionDecl = dyn_cast<FunctionDecl>(declRefExpr->getDecl()); + if (!functionDecl) + { + return true; + } + logCallToRootMethods(currentFunctionDecl, functionDecl->getCanonicalDecl()); + + return true; +} + +bool MethodCycles::TraverseFunctionDecl(FunctionDecl* f) +{ + auto copy = currentFunctionDecl; + currentFunctionDecl = f; + bool ret = RecursiveASTVisitor::TraverseFunctionDecl(f); + currentFunctionDecl = copy; + return ret; +} +bool MethodCycles::TraverseCXXMethodDecl(CXXMethodDecl* f) +{ + auto copy = currentFunctionDecl; + currentFunctionDecl = f; + bool ret = RecursiveASTVisitor::TraverseCXXMethodDecl(f); + currentFunctionDecl = copy; + return ret; +} +bool MethodCycles::TraverseCXXConversionDecl(CXXConversionDecl* f) +{ + auto copy = currentFunctionDecl; + currentFunctionDecl = f; + bool ret = RecursiveASTVisitor::TraverseCXXConversionDecl(f); + currentFunctionDecl = copy; + return ret; +} +bool MethodCycles::TraverseCXXDeductionGuideDecl(CXXDeductionGuideDecl* f) +{ + auto copy = currentFunctionDecl; + currentFunctionDecl = f; + bool ret = RecursiveASTVisitor::TraverseCXXDeductionGuideDecl(f); + currentFunctionDecl = copy; + return ret; +} +bool MethodCycles::TraverseCXXConstructorDecl(CXXConstructorDecl* f) +{ + auto copy = currentFunctionDecl; + currentFunctionDecl = f; + bool ret = RecursiveASTVisitor::TraverseCXXConstructorDecl(f); + currentFunctionDecl = copy; + return ret; +} +bool MethodCycles::TraverseCXXDestructorDecl(CXXDestructorDecl* f) +{ + auto copy = currentFunctionDecl; + currentFunctionDecl = f; + bool ret = RecursiveASTVisitor::TraverseCXXDestructorDecl(f); + currentFunctionDecl = copy; + return ret; +} + +loplugin::Plugin::Registration<MethodCycles> X("methodcycles", false); +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |