/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2019 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 .
*/
/**
* @brief This is the ValueFlow component in Cppcheck.
*
* Each @sa Token in the token list has a list of values. These are
* the "possible" values for the Token at runtime.
*
* In the --debug and --debug-normal output you can see the ValueFlow data. For example:
*
* int f()
* {
* int x = 10;
* return 4 * x + 2;
* }
*
* The --debug-normal output says:
*
* ##Value flow
* Line 3
* 10 always 10
* Line 4
* 4 always 4
* * always 40
* x always 10
* + always 42
* 2 always 2
*
* All value flow analysis is executed in the ValueFlow::setValues() function. The ValueFlow analysis is executed after the tokenizer/ast/symboldatabase/etc..
* The ValueFlow analysis is done in a series of valueFlow* function calls, where each such function call can only use results from previous function calls.
* The function calls should be arranged so that valueFlow* that do not require previous ValueFlow information should be first.
*
* Type of analysis
* ================
*
* This is "flow sensitive" value flow analysis. We _usually_ track the value for 1 variable at a time.
*
* How are calculations handled
* ============================
*
* Here is an example code:
*
* x = 3 + 4;
*
* The valueFlowNumber set the values for the "3" and "4" tokens by calling setTokenValue().
* The setTokenValue() handle the calculations automatically. When both "3" and "4" have values, the "+" can be calculated. setTokenValue() recursively calls itself when parents in calculations can be calculated.
*
* Forward / Reverse flow analysis
* ===============================
*
* In forward value flow analysis we know a value and see what happens when we are stepping the program forward. Like normal execution.
* The valueFlowForward is used in this analysis.
*
* In reverse value flow analysis we know the value of a variable at line X. And try to "execute backwards" to determine possible values before line X.
* The valueFlowReverse is used in this analysis.
*
*
*/
#include "valueflow.h"
#include "astutils.h"
#include "errorlogger.h"
#include "library.h"
#include "mathlib.h"
#include "platform.h"
#include "settings.h"
#include "standards.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenlist.h"
#include "utils.h"
#include "path.h"
#include
#include
#include
#include
#include
#include
#include