office-gobmx/compilerplugins/clang/constfields.cxx
Stephan Bergmann d1a2b80b9d Bump compiler plugins Clang baseline to 12.0.1
...as discussed in the mail thread starting at
<https://lists.freedesktop.org/archives/libreoffice/2020-November/086234.html>
"Bump --enable-compiler-plugins Clang baseline?" (and now picked up again at
<https://lists.freedesktop.org/archives/libreoffice/2022-February/088459.html>
"Re: Bump --enable-compiler-plugins Clang baseline?"), and clean up
compilerplugins/clang/ accordingly

Change-Id: I5e81c6fdcc363aeefd6227606225b526fdf7ac16
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129989
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
2022-02-17 21:45:06 +01:00

596 lines
20 KiB
C++

/* -*- 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/.
*/
#if !defined _WIN32 //TODO, #include <sys/file.h>
#include <cassert>
#include <string>
#include <iostream>
#include <fstream>
#include <unordered_set>
#include <vector>
#include <algorithm>
#include <sys/file.h>
#include <unistd.h>
#include "config_clang.h"
#include "plugin.hxx"
#include "check.hxx"
#include "clang/AST/ParentMapContext.h"
/**
Look for fields that are only assigned to in the constructor using field-init, and can therefore be const.
The process goes something like this:
$ make check
$ make FORCE_COMPILE=all COMPILER_PLUGIN_TOOL='constfields' check
$ ./compilerplugins/clang/constfields.py
and then
$ for dir in *; do make $dir FORCE_COMPILE=all UPDATE_FILES=$dir COMPILER_PLUGIN_TOOL='constfieldsrewrite' $dir; done
to auto-remove the method declarations
*/
namespace
{
struct MyFieldInfo
{
const RecordDecl* parentRecord;
std::string parentClass;
std::string fieldName;
std::string fieldType;
std::string sourceLocation;
std::string access;
};
bool operator<(const MyFieldInfo& lhs, const MyFieldInfo& rhs)
{
return std::tie(lhs.parentClass, lhs.fieldName) < std::tie(rhs.parentClass, rhs.fieldName);
}
// try to limit the voluminous output a little
static std::set<MyFieldInfo> cannotBeConstSet;
static std::set<MyFieldInfo> definitionSet;
/**
* Wrap the different kinds of callable and callee objects in the clang AST so I can define methods that handle everything.
*/
class CallerWrapper
{
const CallExpr* m_callExpr;
const CXXConstructExpr* m_cxxConstructExpr;
public:
CallerWrapper(const CallExpr* callExpr)
: m_callExpr(callExpr)
, m_cxxConstructExpr(nullptr)
{
}
CallerWrapper(const CXXConstructExpr* cxxConstructExpr)
: m_callExpr(nullptr)
, m_cxxConstructExpr(cxxConstructExpr)
{
}
unsigned getNumArgs() const
{
return m_callExpr ? m_callExpr->getNumArgs() : m_cxxConstructExpr->getNumArgs();
}
const Expr* getArg(unsigned i) const
{
return m_callExpr ? m_callExpr->getArg(i) : m_cxxConstructExpr->getArg(i);
}
};
class CalleeWrapper
{
const FunctionDecl* m_calleeFunctionDecl = nullptr;
const CXXConstructorDecl* m_cxxConstructorDecl = nullptr;
const FunctionProtoType* m_functionPrototype = nullptr;
public:
explicit CalleeWrapper(const FunctionDecl* calleeFunctionDecl)
: m_calleeFunctionDecl(calleeFunctionDecl)
{
}
explicit CalleeWrapper(const CXXConstructExpr* cxxConstructExpr)
: m_cxxConstructorDecl(cxxConstructExpr->getConstructor())
{
}
explicit CalleeWrapper(const FunctionProtoType* functionPrototype)
: m_functionPrototype(functionPrototype)
{
}
unsigned getNumParams() const
{
if (m_calleeFunctionDecl)
return m_calleeFunctionDecl->getNumParams();
else if (m_cxxConstructorDecl)
return m_cxxConstructorDecl->getNumParams();
else if (m_functionPrototype->param_type_begin() == m_functionPrototype->param_type_end())
// FunctionProtoType will assert if we call getParamTypes() and it has no params
return 0;
else
return m_functionPrototype->getParamTypes().size();
}
const QualType getParamType(unsigned i) const
{
if (m_calleeFunctionDecl)
return m_calleeFunctionDecl->getParamDecl(i)->getType();
else if (m_cxxConstructorDecl)
return m_cxxConstructorDecl->getParamDecl(i)->getType();
else
return m_functionPrototype->getParamTypes()[i];
}
std::string getNameAsString() const
{
if (m_calleeFunctionDecl)
return m_calleeFunctionDecl->getNameAsString();
else if (m_cxxConstructorDecl)
return m_cxxConstructorDecl->getNameAsString();
else
return "";
}
CXXMethodDecl const* getAsCXXMethodDecl() const
{
if (m_calleeFunctionDecl)
return dyn_cast<CXXMethodDecl>(m_calleeFunctionDecl);
return nullptr;
}
};
class ConstFields : public RecursiveASTVisitor<ConstFields>, public loplugin::Plugin
{
public:
explicit ConstFields(loplugin::InstantiationData const& data)
: Plugin(data)
{
}
virtual void run() override;
bool shouldVisitTemplateInstantiations() const { return true; }
bool shouldVisitImplicitCode() const { return true; }
bool VisitFieldDecl(const FieldDecl*);
bool VisitMemberExpr(const MemberExpr*);
bool TraverseCXXConstructorDecl(CXXConstructorDecl*);
bool TraverseCXXMethodDecl(CXXMethodDecl*);
bool TraverseFunctionDecl(FunctionDecl*);
bool TraverseIfStmt(IfStmt*);
private:
MyFieldInfo niceName(const FieldDecl*);
void check(const FieldDecl* fieldDecl, const Expr* memberExpr);
bool isSomeKindOfZero(const Expr* arg);
bool IsPassedByNonConst(const FieldDecl* fieldDecl, const Stmt* child, CallerWrapper callExpr,
CalleeWrapper calleeFunctionDecl);
llvm::Optional<CalleeWrapper> getCallee(CallExpr const*);
RecordDecl* insideMoveOrCopyDeclParent = nullptr;
// For reasons I do not understand, parentFunctionDecl() is not reliable, so
// we store the parent function on the way down the AST.
FunctionDecl* insideFunctionDecl = nullptr;
std::vector<FieldDecl const*> insideConditionalCheckOfMemberSet;
};
void ConstFields::run()
{
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
if (!isUnitTestMode())
{
// 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 MyFieldInfo& s : cannotBeConstSet)
output += "write-outside-constructor:\t" + s.parentClass + "\t" + s.fieldName + "\n";
for (const MyFieldInfo& s : definitionSet)
output += "definition:\t" + s.access + "\t" + s.parentClass + "\t" + s.fieldName + "\t"
+ s.fieldType + "\t" + s.sourceLocation + "\n";
std::ofstream myfile;
myfile.open(WORKDIR "/loplugin.constfields.log", std::ios::app | std::ios::out);
myfile << output;
myfile.close();
}
else
{
for (const MyFieldInfo& s : cannotBeConstSet)
report(DiagnosticsEngine::Warning, "notconst %0", s.parentRecord->getBeginLoc())
<< s.fieldName;
}
}
MyFieldInfo ConstFields::niceName(const FieldDecl* fieldDecl)
{
MyFieldInfo aInfo;
const RecordDecl* recordDecl = fieldDecl->getParent();
if (const CXXRecordDecl* cxxRecordDecl = dyn_cast<CXXRecordDecl>(recordDecl))
{
if (cxxRecordDecl->getTemplateInstantiationPattern())
cxxRecordDecl = cxxRecordDecl->getTemplateInstantiationPattern();
aInfo.parentRecord = cxxRecordDecl;
aInfo.parentClass = cxxRecordDecl->getQualifiedNameAsString();
}
else
{
aInfo.parentRecord = recordDecl;
aInfo.parentClass = recordDecl->getQualifiedNameAsString();
}
aInfo.fieldName = fieldDecl->getNameAsString();
// sometimes the name (if it's an anonymous thing) contains the full path of the build folder, which we don't need
size_t idx = aInfo.fieldName.find(SRCDIR);
if (idx != std::string::npos)
{
aInfo.fieldName = aInfo.fieldName.replace(idx, strlen(SRCDIR), "");
}
aInfo.fieldType = fieldDecl->getType().getAsString();
SourceLocation expansionLoc
= compiler.getSourceManager().getExpansionLoc(fieldDecl->getLocation());
StringRef name = getFilenameOfLocation(expansionLoc);
aInfo.sourceLocation
= std::string(name.substr(strlen(SRCDIR) + 1)) + ":"
+ std::to_string(compiler.getSourceManager().getSpellingLineNumber(expansionLoc));
loplugin::normalizeDotDotInFilePath(aInfo.sourceLocation);
switch (fieldDecl->getAccess())
{
case AS_public:
aInfo.access = "public";
break;
case AS_private:
aInfo.access = "private";
break;
case AS_protected:
aInfo.access = "protected";
break;
default:
aInfo.access = "unknown";
break;
}
return aInfo;
}
bool ConstFields::VisitFieldDecl(const FieldDecl* fieldDecl)
{
fieldDecl = fieldDecl->getCanonicalDecl();
if (ignoreLocation(fieldDecl))
{
return true;
}
// ignore stuff that forms part of the stable URE interface
if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(fieldDecl->getLocation())))
{
return true;
}
definitionSet.insert(niceName(fieldDecl));
return true;
}
bool ConstFields::TraverseCXXConstructorDecl(CXXConstructorDecl* cxxConstructorDecl)
{
auto copy = insideMoveOrCopyDeclParent;
if (!ignoreLocation(cxxConstructorDecl) && cxxConstructorDecl->isThisDeclarationADefinition())
{
if (cxxConstructorDecl->isCopyOrMoveConstructor())
insideMoveOrCopyDeclParent = cxxConstructorDecl->getParent();
}
bool ret = RecursiveASTVisitor::TraverseCXXConstructorDecl(cxxConstructorDecl);
insideMoveOrCopyDeclParent = copy;
return ret;
}
bool ConstFields::TraverseCXXMethodDecl(CXXMethodDecl* cxxMethodDecl)
{
auto copy1 = insideMoveOrCopyDeclParent;
auto copy2 = insideFunctionDecl;
if (!ignoreLocation(cxxMethodDecl) && cxxMethodDecl->isThisDeclarationADefinition())
{
if (cxxMethodDecl->isCopyAssignmentOperator() || cxxMethodDecl->isMoveAssignmentOperator())
insideMoveOrCopyDeclParent = cxxMethodDecl->getParent();
}
insideFunctionDecl = cxxMethodDecl;
bool ret = RecursiveASTVisitor::TraverseCXXMethodDecl(cxxMethodDecl);
insideMoveOrCopyDeclParent = copy1;
insideFunctionDecl = copy2;
return ret;
}
bool ConstFields::TraverseFunctionDecl(FunctionDecl* functionDecl)
{
auto copy2 = insideFunctionDecl;
insideFunctionDecl = functionDecl;
bool ret = RecursiveASTVisitor::TraverseFunctionDecl(functionDecl);
insideFunctionDecl = copy2;
return ret;
}
bool ConstFields::TraverseIfStmt(IfStmt* ifStmt)
{
FieldDecl const* memberFieldDecl = nullptr;
if (Expr const* cond = ifStmt->getCond())
{
if (auto memberExpr = dyn_cast<MemberExpr>(cond->IgnoreParenImpCasts()))
{
if ((memberFieldDecl = dyn_cast<FieldDecl>(memberExpr->getMemberDecl())))
insideConditionalCheckOfMemberSet.push_back(memberFieldDecl);
}
}
bool ret = RecursiveASTVisitor::TraverseIfStmt(ifStmt);
if (memberFieldDecl)
insideConditionalCheckOfMemberSet.pop_back();
return ret;
}
bool ConstFields::VisitMemberExpr(const MemberExpr* memberExpr)
{
const ValueDecl* decl = memberExpr->getMemberDecl();
const FieldDecl* fieldDecl = dyn_cast<FieldDecl>(decl);
if (!fieldDecl)
{
return true;
}
fieldDecl = fieldDecl->getCanonicalDecl();
if (ignoreLocation(fieldDecl))
{
return true;
}
// ignore stuff that forms part of the stable URE interface
if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(fieldDecl->getLocation())))
{
return true;
}
check(fieldDecl, memberExpr);
return true;
}
void ConstFields::check(const FieldDecl* fieldDecl, const Expr* memberExpr)
{
auto parentsRange = compiler.getASTContext().getParents(*memberExpr);
const Stmt* child = memberExpr;
const Stmt* parent
= parentsRange.begin() == parentsRange.end() ? nullptr : parentsRange.begin()->get<Stmt>();
// walk up the tree until we find something interesting
bool bCannotBeConst = false;
bool bDump = false;
auto walkUp = [&]() {
child = parent;
auto parentsRange = compiler.getASTContext().getParents(*parent);
parent = parentsRange.begin() == parentsRange.end() ? nullptr
: parentsRange.begin()->get<Stmt>();
};
do
{
if (!parent)
{
// check if we have an expression like
// int& r = m_field;
auto parentsRange = compiler.getASTContext().getParents(*child);
if (parentsRange.begin() != parentsRange.end())
{
auto varDecl = dyn_cast_or_null<VarDecl>(parentsRange.begin()->get<Decl>());
// The isImplicit() call is to avoid triggering when we see the vardecl which is part of a for-range statement,
// which is of type 'T&&' and also an l-value-ref ?
if (varDecl && !varDecl->isImplicit()
&& loplugin::TypeCheck(varDecl->getType()).LvalueReference().NonConst())
{
bCannotBeConst = true;
}
}
break;
}
if (isa<CXXReinterpretCastExpr>(parent))
{
// once we see one of these, there is not much useful we can know
bCannotBeConst = true;
break;
}
else if (isa<CastExpr>(parent) || isa<MemberExpr>(parent) || isa<ParenExpr>(parent)
|| isa<ParenListExpr>(parent) || isa<ArrayInitLoopExpr>(parent)
|| isa<ExprWithCleanups>(parent))
{
walkUp();
}
else if (auto unaryOperator = dyn_cast<UnaryOperator>(parent))
{
UnaryOperator::Opcode op = unaryOperator->getOpcode();
if (op == UO_AddrOf || op == UO_PostInc || op == UO_PostDec || op == UO_PreInc
|| op == UO_PreDec)
{
bCannotBeConst = true;
}
walkUp();
}
else if (auto operatorCallExpr = dyn_cast<CXXOperatorCallExpr>(parent))
{
auto callee = getCallee(operatorCallExpr);
if (callee)
{
// if calling a non-const operator on the field
auto calleeMethodDecl = callee->getAsCXXMethodDecl();
if (calleeMethodDecl && operatorCallExpr->getArg(0) == child
&& !calleeMethodDecl->isConst())
{
bCannotBeConst = true;
}
else if (IsPassedByNonConst(fieldDecl, child, operatorCallExpr, *callee))
{
bCannotBeConst = true;
}
}
else
bCannotBeConst = true; // conservative, could improve
walkUp();
}
else if (auto cxxMemberCallExpr = dyn_cast<CXXMemberCallExpr>(parent))
{
const CXXMethodDecl* calleeMethodDecl = cxxMemberCallExpr->getMethodDecl();
if (calleeMethodDecl)
{
// if calling a non-const method on the field
const Expr* tmp = dyn_cast<Expr>(child);
if (tmp->isBoundMemberFunction(compiler.getASTContext()))
{
tmp = dyn_cast<MemberExpr>(tmp)->getBase();
}
if (cxxMemberCallExpr->getImplicitObjectArgument() == tmp
&& !calleeMethodDecl->isConst())
{
bCannotBeConst = true;
break;
}
if (IsPassedByNonConst(fieldDecl, child, cxxMemberCallExpr,
CalleeWrapper(calleeMethodDecl)))
bCannotBeConst = true;
}
else
bCannotBeConst = true; // can happen in templates
walkUp();
}
else if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(parent))
{
if (IsPassedByNonConst(fieldDecl, child, cxxConstructExpr,
CalleeWrapper(cxxConstructExpr)))
bCannotBeConst = true;
walkUp();
}
else if (auto callExpr = dyn_cast<CallExpr>(parent))
{
auto callee = getCallee(callExpr);
if (callee)
{
if (IsPassedByNonConst(fieldDecl, child, callExpr, *callee))
bCannotBeConst = true;
}
else
bCannotBeConst = true; // conservative, could improve
walkUp();
}
else if (auto binaryOp = dyn_cast<BinaryOperator>(parent))
{
BinaryOperator::Opcode op = binaryOp->getOpcode();
const bool assignmentOp = op == BO_Assign || op == BO_MulAssign || op == BO_DivAssign
|| op == BO_RemAssign || op == BO_AddAssign
|| op == BO_SubAssign || op == BO_ShlAssign
|| op == BO_ShrAssign || op == BO_AndAssign
|| op == BO_XorAssign || op == BO_OrAssign;
if (assignmentOp)
{
if (binaryOp->getLHS() == child)
bCannotBeConst = true;
else if (loplugin::TypeCheck(binaryOp->getLHS()->getType())
.LvalueReference()
.NonConst())
// if the LHS is a non-const reference, we could write to the field later on
bCannotBeConst = true;
}
walkUp();
}
else if (isa<ReturnStmt>(parent))
{
if (insideFunctionDecl)
{
auto tc = loplugin::TypeCheck(insideFunctionDecl->getReturnType());
if (tc.LvalueReference().NonConst())
bCannotBeConst = true;
}
break;
}
else if (isa<SwitchStmt>(parent) || isa<WhileStmt>(parent) || isa<ForStmt>(parent)
|| isa<IfStmt>(parent) || isa<DoStmt>(parent) || isa<CXXForRangeStmt>(parent)
|| isa<DefaultStmt>(parent))
{
break;
}
else
{
walkUp();
}
} while (true);
if (bDump)
{
report(DiagnosticsEngine::Warning, "oh dear, what can the matter be? writtenTo=%0",
memberExpr->getBeginLoc())
<< bCannotBeConst << memberExpr->getSourceRange();
if (parent)
{
report(DiagnosticsEngine::Note, "parent over here", parent->getBeginLoc())
<< parent->getSourceRange();
parent->dump();
}
memberExpr->dump();
fieldDecl->getType()->dump();
}
if (bCannotBeConst)
{
cannotBeConstSet.insert(niceName(fieldDecl));
}
}
bool ConstFields::IsPassedByNonConst(const FieldDecl* fieldDecl, const Stmt* child,
CallerWrapper callExpr, CalleeWrapper calleeFunctionDecl)
{
unsigned len = std::min(callExpr.getNumArgs(), calleeFunctionDecl.getNumParams());
// if it's an array, passing it by value to a method typically means the
// callee takes a pointer and can modify the array
if (fieldDecl->getType()->isConstantArrayType())
{
for (unsigned i = 0; i < len; ++i)
if (callExpr.getArg(i) == child)
if (loplugin::TypeCheck(calleeFunctionDecl.getParamType(i)).Pointer().NonConst())
return true;
}
else
{
for (unsigned i = 0; i < len; ++i)
if (callExpr.getArg(i) == child)
if (loplugin::TypeCheck(calleeFunctionDecl.getParamType(i))
.LvalueReference()
.NonConst())
return true;
}
return false;
}
llvm::Optional<CalleeWrapper> ConstFields::getCallee(CallExpr const* callExpr)
{
FunctionDecl const* functionDecl = callExpr->getDirectCallee();
if (functionDecl)
return CalleeWrapper(functionDecl);
// Extract the functionprototype from a type
clang::Type const* calleeType = callExpr->getCallee()->getType().getTypePtr();
if (auto pointerType = calleeType->getUnqualifiedDesugaredType()->getAs<clang::PointerType>())
{
if (auto prototype = pointerType->getPointeeType()
->getUnqualifiedDesugaredType()
->getAs<FunctionProtoType>())
{
return CalleeWrapper(prototype);
}
}
return llvm::Optional<CalleeWrapper>();
}
loplugin::Plugin::Registration<ConstFields> X("constfields", false);
}
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */