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cppcheck/lib/astutils.h

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2022 Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
#ifndef astutilsH
#define astutilsH
//---------------------------------------------------------------------------
#include <functional>
#include <set>
#include <stack>
#include <string>
#include <vector>
#include "config.h"
#include "errortypes.h"
#include "symboldatabase.h"
class Library;
class Settings;
class Token;
enum class ChildrenToVisit {
none,
op1,
op2,
op1_and_op2,
done // found what we looked for, don't visit any more children
};
/**
* Visit AST nodes recursively. The order is not "well defined"
*/
template<class T, class TFunc, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
void visitAstNodes(T *ast, const TFunc &visitor)
{
if (!ast)
return;
std::stack<T *, std::vector<T *>> tokens;
T *tok = ast;
do {
ChildrenToVisit c = visitor(tok);
if (c == ChildrenToVisit::done)
break;
if (c == ChildrenToVisit::op2 || c == ChildrenToVisit::op1_and_op2) {
T *t2 = tok->astOperand2();
if (t2)
tokens.push(t2);
}
if (c == ChildrenToVisit::op1 || c == ChildrenToVisit::op1_and_op2) {
T *t1 = tok->astOperand1();
if (t1)
tokens.push(t1);
}
if (tokens.empty())
break;
tok = tokens.top();
tokens.pop();
} while (true);
}
template<class TFunc>
const Token* findAstNode(const Token* ast, const TFunc& pred)
{
const Token* result = nullptr;
visitAstNodes(ast, [&](const Token* tok) {
if (pred(tok)) {
result = tok;
return ChildrenToVisit::done;
}
return ChildrenToVisit::op1_and_op2;
});
return result;
}
const Token* findExpression(const nonneg int exprid,
const Token* start,
const Token* end,
const std::function<bool(const Token*)>& pred);
const Token* findExpression(const Token* start, const nonneg int exprid);
std::vector<const Token*> astFlatten(const Token* tok, const char* op);
std::vector<Token*> astFlatten(Token* tok, const char* op);
nonneg int astCount(const Token* tok, const char* op, int depth = 100);
bool astHasToken(const Token* root, const Token * tok);
bool astHasVar(const Token * tok, nonneg int varid);
bool astIsPrimitive(const Token* tok);
/** Is expression a 'signed char' if no promotion is used */
bool astIsSignedChar(const Token *tok);
/** Is expression a 'char' if no promotion is used? */
bool astIsUnknownSignChar(const Token *tok);
/** Is expression a char according to valueType? */
bool astIsGenericChar(const Token* tok);
/** Is expression of integral type? */
bool astIsIntegral(const Token *tok, bool unknown);
bool astIsUnsigned(const Token* tok);
/** Is expression of floating point type? */
bool astIsFloat(const Token *tok, bool unknown);
/** Is expression of boolean type? */
bool astIsBool(const Token *tok);
bool astIsPointer(const Token *tok);
bool astIsSmartPointer(const Token* tok);
bool astIsUniqueSmartPointer(const Token* tok);
bool astIsIterator(const Token *tok);
bool astIsContainer(const Token *tok);
bool astIsContainerView(const Token* tok);
bool astIsContainerOwned(const Token* tok);
/**
* Get canonical type of expression. const/static/etc are not included and neither *&.
* For example:
* Expression type Return
* std::string std::string
* int * int
* static const int int
* std::vector<T> std::vector
*/
std::string astCanonicalType(const Token *expr);
/** Is given syntax tree a variable comparison against value */
const Token * astIsVariableComparison(const Token *tok, const std::string &comp, const std::string &rhs, const Token **vartok=nullptr);
bool isVariableDecl(const Token* tok);
bool isTemporary(bool cpp, const Token* tok, const Library* library, bool unknown = false);
const Token* previousBeforeAstLeftmostLeaf(const Token* tok);
Token* previousBeforeAstLeftmostLeaf(Token* tok);
const Token * nextAfterAstRightmostLeaf(const Token * tok);
Token* nextAfterAstRightmostLeaf(Token* tok);
Token* astParentSkipParens(Token* tok);
const Token* astParentSkipParens(const Token* tok);
const Token* getParentMember(const Token * tok);
const Token* getParentLifetime(const Token* tok);
const Token* getParentLifetime(bool cpp, const Token* tok, const Library* library);
bool astIsLHS(const Token* tok);
bool astIsRHS(const Token* tok);
Token* getCondTok(Token* tok);
const Token* getCondTok(const Token* tok);
Token* getInitTok(Token* tok);
const Token* getInitTok(const Token* tok);
Token* getStepTok(Token* tok);
const Token* getStepTok(const Token* tok);
Token* getCondTokFromEnd(Token* endBlock);
const Token* getCondTokFromEnd(const Token* endBlock);
/// For a "break" token, locate the next token to execute. The token will
/// be either a "}" or a ";".
const Token *findNextTokenFromBreak(const Token *breakToken);
/**
* Extract for loop values: loopvar varid, init value, step value, last value (inclusive)
*/
bool extractForLoopValues(const Token *forToken,
nonneg int * const varid,
bool * const knownInitValue,
long long * const initValue,
bool * const partialCond,
long long * const stepValue,
long long * const lastValue);
bool precedes(const Token * tok1, const Token * tok2);
bool succeeds(const Token* tok1, const Token* tok2);
bool exprDependsOnThis(const Token* expr, bool onVar = true, nonneg int depth = 0);
struct ReferenceToken {
const Token* token;
ErrorPath errors;
};
std::vector<ReferenceToken> followAllReferences(const Token* tok,
bool temporary = true,
bool inconclusive = true,
ErrorPath errors = ErrorPath{},
int depth = 20);
const Token* followReferences(const Token* tok, ErrorPath* errors = nullptr);
bool isSameExpression(bool cpp, bool macro, const Token *tok1, const Token *tok2, const Library& library, bool pure, bool followVar, ErrorPath* errors=nullptr);
bool isEqualKnownValue(const Token * const tok1, const Token * const tok2);
bool isStructuredBindingVariable(const Variable* var);
/**
* Is token used a boolean, that is to say cast to a bool, or used as a condition in a if/while/for
*/
bool isUsedAsBool(const Token * const tok);
/**
* Are two conditions opposite
* @param isNot do you want to know if cond1 is !cond2 or if cond1 and cond2 are non-overlapping. true: cond1==!cond2 false: cond1==true => cond2==false
* @param cpp c++ file
* @param cond1 condition1
* @param cond2 condition2
* @param library files data
* @param pure boolean
*/
bool isOppositeCond(bool isNot, bool cpp, const Token * const cond1, const Token * const cond2, const Library& library, bool pure, bool followVar, ErrorPath* errors=nullptr);
bool isOppositeExpression(bool cpp, const Token * const tok1, const Token * const tok2, const Library& library, bool pure, bool followVar, ErrorPath* errors=nullptr);
bool isConstFunctionCall(const Token* ftok, const Library& library);
bool isConstExpression(const Token *tok, const Library& library, bool pure, bool cpp);
bool isWithoutSideEffects(bool cpp, const Token* tok, bool checkArrayAccess = false, bool checkReference = true);
bool isUniqueExpression(const Token* tok);
bool isEscapeFunction(const Token* ftok, const Library* library);
/** Is scope a return scope (scope will unconditionally return) */
bool isReturnScope(const Token* const endToken,
const Library* library = nullptr,
const Token** unknownFunc = nullptr,
bool functionScope = false);
/** Is tok within a scope of the given type, nested within var's scope? */
bool isWithinScope(const Token* tok,
const Variable* var,
Scope::ScopeType type);
/// Return the token to the function and the argument number
const Token * getTokenArgumentFunction(const Token * tok, int& argn);
Token* getTokenArgumentFunction(Token* tok, int& argn);
std::vector<const Variable*> getArgumentVars(const Token* tok, int argnr);
/** Is variable changed by function call?
* In case the answer of the question is inconclusive, e.g. because the function declaration is not known
* the return value is false and the output parameter inconclusive is set to true
*
* @param tok ast tree
* @param varid Variable Id
* @param settings program settings
* @param inconclusive pointer to output variable which indicates that the answer of the question is inconclusive
*/
bool isVariableChangedByFunctionCall(const Token *tok, int indirect, nonneg int varid, const Settings *settings, bool *inconclusive);
/** Is variable changed by function call?
* In case the answer of the question is inconclusive, e.g. because the function declaration is not known
* the return value is false and the output parameter inconclusive is set to true
*
* @param tok token of variable in function call
* @param settings program settings
* @param inconclusive pointer to output variable which indicates that the answer of the question is inconclusive
*/
bool isVariableChangedByFunctionCall(const Token *tok, int indirect, const Settings *settings, bool *inconclusive);
/** Is variable changed in block of code? */
bool isVariableChanged(const Token *start, const Token *end, const nonneg int exprid, bool globalvar, const Settings *settings, bool cpp, int depth = 20);
bool isVariableChanged(const Token *start, const Token *end, int indirect, const nonneg int exprid, bool globalvar, const Settings *settings, bool cpp, int depth = 20);
bool isVariableChanged(const Token *tok, int indirect, const Settings *settings, bool cpp, int depth = 20);
bool isVariableChanged(const Variable * var, const Settings *settings, bool cpp, int depth = 20);
bool isVariablesChanged(const Token* start,
const Token* end,
int indirect,
std::vector<const Variable*> vars,
const Settings* settings,
bool cpp);
bool isThisChanged(const Token* tok, int indirect, const Settings* settings, bool cpp);
bool isThisChanged(const Token* start, const Token* end, int indirect, const Settings* settings, bool cpp);
const Token* findVariableChanged(const Token *start, const Token *end, int indirect, const nonneg int exprid, bool globalvar, const Settings *settings, bool cpp, int depth = 20);
Token* findVariableChanged(Token *start, const Token *end, int indirect, const nonneg int exprid, bool globalvar, const Settings *settings, bool cpp, int depth = 20);
bool isExpressionChanged(const Token* expr,
const Token* start,
const Token* end,
const Settings* settings,
bool cpp,
int depth = 20);
bool isExpressionChangedAt(const Token* expr,
const Token* tok,
int indirect,
bool globalvar,
const Settings* settings,
bool cpp,
int depth = 20);
/// If token is an alias if another variable
bool isAliasOf(const Token *tok, nonneg int varid, bool* inconclusive = nullptr);
bool isAliased(const Variable *var);
const Token* getArgumentStart(const Token* ftok);
/** Determines the number of arguments - if token is a function call or macro
* @param ftok start token which is supposed to be the function/macro name.
* @return Number of arguments
*/
int numberOfArguments(const Token* ftok);
/// Get number of arguments without using AST
int numberOfArgumentsWithoutAst(const Token* start);
/**
* Get arguments (AST)
*/
std::vector<const Token *> getArguments(const Token *ftok);
int getArgumentPos(const Variable* var, const Function* f);
/**
* Are the arguments a pair of iterators/pointers?
*/
bool isIteratorPair(std::vector<const Token*> args);
const Token *findLambdaStartToken(const Token *last);
/**
* find lambda function end token
* \param first The [ token
* \return nullptr or the }
*/
const Token *findLambdaEndToken(const Token *first);
Token* findLambdaEndToken(Token* first);
bool isLikelyStream(bool cpp, const Token *stream);
/**
* do we see a likely write of rhs through overloaded operator
* s >> x;
* a & x;
*/
bool isLikelyStreamRead(bool cpp, const Token *op);
bool isCPPCast(const Token* tok);
bool isConstVarExpression(const Token *tok, const char * skipMatch = nullptr);
const Variable *getLHSVariable(const Token *tok);
const Token* getLHSVariableToken(const Token* tok);
std::vector<const Variable*> getLHSVariables(const Token* tok);
/** Find a allocation function call in expression, so result of expression is allocated memory/resource. */
const Token* findAllocFuncCallToken(const Token *expr, const Library &library);
bool isScopeBracket(const Token* tok);
bool isNullOperand(const Token *expr);
bool isGlobalData(const Token *expr, bool cpp);
/**
* Forward data flow analysis for checks
* - unused value
* - redundant assignment
* - valueflow analysis
*/
class FwdAnalysis {
public:
FwdAnalysis(bool cpp, const Library &library) : mCpp(cpp), mLibrary(library), mWhat(What::Reassign), mValueFlowKnown(true) {}
bool hasOperand(const Token *tok, const Token *lhs) const;
/**
* Check if "expr" is reassigned. The "expr" can be a tree (x.y[12]).
* @param expr Symbolic expression to perform forward analysis for
* @param startToken First token in forward analysis
* @param endToken Last token in forward analysis
* @return Token where expr is reassigned. If it's not reassigned then nullptr is returned.
*/
const Token *reassign(const Token *expr, const Token *startToken, const Token *endToken);
/**
* Check if "expr" is used. The "expr" can be a tree (x.y[12]).
* @param expr Symbolic expression to perform forward analysis for
* @param startToken First token in forward analysis
* @param endToken Last token in forward analysis
* @return true if expr is used.
*/
bool unusedValue(const Token *expr, const Token *startToken, const Token *endToken);
struct KnownAndToken {
bool known;
const Token *token;
};
/** Is there some possible alias for given expression */
bool possiblyAliased(const Token *expr, const Token *startToken) const;
std::set<nonneg int> getExprVarIds(const Token* expr, bool* localOut = nullptr, bool* unknownVarIdOut = nullptr) const;
private:
static bool isEscapedAlias(const Token* expr);
/** Result of forward analysis */
struct Result {
enum class Type { NONE, READ, WRITE, BREAK, RETURN, BAILOUT } type;
explicit Result(Type type) : type(type), token(nullptr) {}
Result(Type type, const Token *token) : type(type), token(token) {}
const Token *token;
};
struct Result check(const Token *expr, const Token *startToken, const Token *endToken);
struct Result checkRecursive(const Token *expr, const Token *startToken, const Token *endToken, const std::set<nonneg int> &exprVarIds, bool local, bool inInnerClass, int depth=0);
// Is expression a l-value global data?
bool isGlobalData(const Token *expr) const;
const bool mCpp;
const Library &mLibrary;
enum class What { Reassign, UnusedValue, ValueFlow } mWhat;
std::vector<KnownAndToken> mValueFlow;
bool mValueFlowKnown;
};
bool isSizeOfEtc(const Token *tok);
#endif // astutilsH
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