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forwardanalyzer.cpp
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931 lines (881 loc) · 43.6 KB
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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2024 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/>.
*/
#include "forwardanalyzer.h"
#include "analyzer.h"
#include "astutils.h"
#include "config.h"
#include "errorlogger.h"
#include "errortypes.h"
#include "mathlib.h"
#include "settings.h"
#include "symboldatabase.h"
#include "token.h"
#include "tokenlist.h"
#include "utils.h"
#include "valueptr.h"
#include "vfvalue.h"
#include <algorithm>
#include <cassert>
#include <cstdio>
#include <cstdint>
#include <functional>
#include <list>
#include <string>
#include <tuple>
#include <type_traits>
#include <utility>
#include <vector>
namespace {
struct ForwardTraversal {
enum class Progress : std::uint8_t { Continue, Break, Skip };
enum class Terminate : std::uint8_t { None, Bail, Inconclusive };
ForwardTraversal(const ValuePtr<Analyzer>& analyzer, const TokenList& tokenList, ErrorLogger& errorLogger, const Settings& settings)
: analyzer(analyzer), tokenList(tokenList), errorLogger(errorLogger), settings(settings)
{}
ValuePtr<Analyzer> analyzer;
const TokenList& tokenList;
ErrorLogger& errorLogger;
const Settings& settings;
Analyzer::Action actions;
bool analyzeOnly{};
bool analyzeTerminate{};
Analyzer::Terminate terminate = Analyzer::Terminate::None;
std::vector<Token*> loopEnds;
int branchCount = 0;
Progress Break(Analyzer::Terminate t = Analyzer::Terminate::None) {
if ((!analyzeOnly || analyzeTerminate) && t != Analyzer::Terminate::None)
terminate = t;
return Progress::Break;
}
struct Branch {
explicit Branch(Token* tok = nullptr) : endBlock(tok) {}
Token* endBlock = nullptr;
Analyzer::Action action = Analyzer::Action::None;
bool check = false;
bool escape = false;
bool escapeUnknown = false;
bool active = false;
bool isEscape() const {
return escape || escapeUnknown;
}
bool isConclusiveEscape() const {
return escape && !escapeUnknown;
}
bool isModified() const {
return action.isModified() && !isConclusiveEscape();
}
bool isInconclusive() const {
return action.isInconclusive() && !isConclusiveEscape();
}
bool isDead() const {
return action.isModified() || action.isInconclusive() || isEscape();
}
};
bool stopUpdates() {
analyzeOnly = true;
return actions.isModified();
}
bool stopOnCondition(const Token* condTok) const
{
if (analyzer->isConditional() && findAstNode(condTok, [](const Token* tok) {
return tok->isIncompleteVar();
}))
return true;
return analyzer->stopOnCondition(condTok);
}
std::pair<bool, bool> evalCond(const Token* tok, const Token* ctx = nullptr) const {
if (!tok)
return std::make_pair(false, false);
std::vector<MathLib::bigint> result = analyzer->evaluate(tok, ctx);
// TODO: We should convert to bool
const bool checkThen = std::any_of(result.cbegin(), result.cend(), [](int x) {
return x != 0;
});
const bool checkElse = std::any_of(result.cbegin(), result.cend(), [](int x) {
return x == 0;
});
return std::make_pair(checkThen, checkElse);
}
bool isConditionTrue(const Token* tok, const Token* ctx = nullptr) const {
return evalCond(tok, ctx).first;
}
template<class T, class F, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
Progress traverseTok(T* tok, const F &f, bool traverseUnknown, T** out = nullptr) {
if (Token::Match(tok, "asm|goto"))
return Break(Analyzer::Terminate::Bail);
if (Token::Match(tok, "setjmp|longjmp (")) {
// Traverse the parameters of the function before escaping
traverseRecursive(tok->next()->astOperand2(), f, traverseUnknown);
return Break(Analyzer::Terminate::Bail);
}
if (Token::simpleMatch(tok, "continue")) {
if (loopEnds.empty())
return Break(Analyzer::Terminate::Escape);
// If we are in a loop then jump to the end
if (out)
*out = loopEnds.back();
} else if (Token::Match(tok, "return|throw")) {
traverseRecursive(tok->astOperand2(), f, traverseUnknown);
traverseRecursive(tok->astOperand1(), f, traverseUnknown);
return Break(Analyzer::Terminate::Escape);
} else if (Token::Match(tok, "%name% (") && isEscapeFunction(tok, &settings.library)) {
// Traverse the parameters of the function before escaping
traverseRecursive(tok->next()->astOperand2(), f, traverseUnknown);
return Break(Analyzer::Terminate::Escape);
} else if (isUnevaluated(tok->previous())) {
if (out)
*out = tok->link();
return Progress::Skip;
} else if (tok->astOperand1() && tok->astOperand2() && Token::Match(tok, "?|&&|%oror%")) {
if (traverseConditional(tok, f, traverseUnknown) == Progress::Break)
return Break();
if (out)
*out = nextAfterAstRightmostLeaf(tok);
return Progress::Skip;
// Skip lambdas
} else if (T* lambdaEndToken = findLambdaEndToken(tok)) {
if (checkScope(lambdaEndToken).isModified())
return Break(Analyzer::Terminate::Bail);
if (out)
*out = lambdaEndToken->next();
// Skip class scope
} else if (tok->str() == "{" && tok->scope() && tok->scope()->isClassOrStruct()) {
if (out)
*out = tok->link();
} else {
if (f(tok) == Progress::Break)
return Break();
}
return Progress::Continue;
}
template<class T, class F, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
Progress traverseRecursive(T* tok, const F &f, bool traverseUnknown, unsigned int recursion=0) {
if (!tok)
return Progress::Continue;
if (recursion > 10000)
return Progress::Skip;
T* firstOp = tok->astOperand1();
T* secondOp = tok->astOperand2();
// Evaluate:
// 1. RHS of assignment before LHS
// 2. Unary op before operand
// 3. Function arguments before function call
if (tok->isAssignmentOp() || !secondOp || isFunctionCall(tok))
std::swap(firstOp, secondOp);
if (firstOp && traverseRecursive(firstOp, f, traverseUnknown, recursion+1) == Progress::Break)
return Break();
const Progress p = tok->isAssignmentOp() ? Progress::Continue : traverseTok(tok, f, traverseUnknown);
if (p == Progress::Break)
return Break();
if (p == Progress::Continue && secondOp && traverseRecursive(secondOp, f, traverseUnknown, recursion+1) == Progress::Break)
return Break();
if (tok->isAssignmentOp() && traverseTok(tok, f, traverseUnknown) == Progress::Break)
return Break();
return Progress::Continue;
}
template<class T, class F, REQUIRES("T must be a Token class", std::is_convertible<T*, const Token*> )>
Progress traverseConditional(T* tok, F f, bool traverseUnknown) {
if (Token::Match(tok, "?|&&|%oror%") && tok->astOperand1() && tok->astOperand2()) {
const T* condTok = tok->astOperand1();
T* childTok = tok->astOperand2();
bool checkThen, checkElse;
std::tie(checkThen, checkElse) = evalCond(condTok);
if (!checkThen && !checkElse) {
if (!traverseUnknown && stopOnCondition(condTok) && stopUpdates()) {
return Progress::Continue;
}
checkThen = true;
checkElse = true;
}
if (childTok->str() == ":") {
if (checkThen && traverseRecursive(childTok->astOperand1(), f, traverseUnknown) == Progress::Break)
return Break();
if (checkElse && traverseRecursive(childTok->astOperand2(), f, traverseUnknown) == Progress::Break)
return Break();
} else {
if (!checkThen && tok->str() == "&&")
return Progress::Continue;
if (!checkElse && tok->str() == "||")
return Progress::Continue;
if (traverseRecursive(childTok, f, traverseUnknown) == Progress::Break)
return Break();
}
}
return Progress::Continue;
}
Progress update(Token* tok) {
Analyzer::Action action = analyzer->analyze(tok, Analyzer::Direction::Forward);
actions |= action;
if (!action.isNone() && !analyzeOnly)
analyzer->update(tok, action, Analyzer::Direction::Forward);
if (action.isInconclusive() && !analyzer->lowerToInconclusive())
return Break(Analyzer::Terminate::Inconclusive);
if (action.isInvalid())
return Break(Analyzer::Terminate::Modified);
if (action.isWrite() && !action.isRead())
// Analysis of this write will continue separately
return Break(Analyzer::Terminate::Modified);
return Progress::Continue;
}
Progress updateTok(Token* tok, Token** out = nullptr) {
auto f = [this](Token* tok2) {
return update(tok2);
};
return traverseTok(tok, f, false, out);
}
Progress updateRecursive(Token* tok) {
auto f = [this](Token* tok2) {
return update(tok2);
};
return traverseRecursive(tok, f, false);
}
Analyzer::Action analyzeRecursive(const Token* start) {
Analyzer::Action result = Analyzer::Action::None;
auto f = [&](const Token* tok) {
result = analyzer->analyze(tok, Analyzer::Direction::Forward);
if (result.isModified() || result.isInconclusive())
return Break();
return Progress::Continue;
};
traverseRecursive(start, f, true);
return result;
}
Analyzer::Action analyzeRange(const Token* start, const Token* end) const {
Analyzer::Action result = Analyzer::Action::None;
for (const Token* tok = start; tok && tok != end; tok = tok->next()) {
Analyzer::Action action = analyzer->analyze(tok, Analyzer::Direction::Forward);
if (action.isModified() || action.isInconclusive())
return action;
result |= action;
}
return result;
}
ForwardTraversal fork(bool analyze = false) const {
ForwardTraversal ft = *this;
if (analyze) {
ft.analyzeOnly = true;
ft.analyzeTerminate = true;
}
ft.actions = Analyzer::Action::None;
return ft;
}
std::vector<ForwardTraversal> tryForkScope(Token* endBlock, bool isModified = false) const {
if (analyzer->updateScope(endBlock, isModified)) {
ForwardTraversal ft = fork();
return {std::move(ft)};
}
return std::vector<ForwardTraversal> {};
}
std::vector<ForwardTraversal> tryForkUpdateScope(Token* endBlock, bool isModified = false) const {
std::vector<ForwardTraversal> result = tryForkScope(endBlock, isModified);
for (ForwardTraversal& ft : result)
ft.updateScope(endBlock);
return result;
}
static bool hasGoto(const Token* endBlock) {
return Token::findsimplematch(endBlock->link(), "goto", endBlock);
}
static bool hasJump(const Token* endBlock) {
return Token::findmatch(endBlock->link(), "goto|break", endBlock);
}
bool hasInnerReturnScope(const Token* start, const Token* end) const {
for (const Token* tok=start; tok != end; tok = tok->previous()) {
if (Token::simpleMatch(tok, "}")) {
const Token* ftok = nullptr;
const bool r = isReturnScope(tok, settings.library, &ftok);
if (r)
return true;
}
}
return false;
}
bool isEscapeScope(const Token* endBlock, bool& unknown) const {
const Token* ftok = nullptr;
const bool r = isReturnScope(endBlock, settings.library, &ftok);
if (!r && ftok)
unknown = true;
return r;
}
enum class Status : std::uint8_t {
None,
Inconclusive,
};
Analyzer::Action analyzeScope(const Token* endBlock) const {
return analyzeRange(endBlock->link(), endBlock);
}
Analyzer::Action checkScope(Token* endBlock) const {
Analyzer::Action a = analyzeScope(endBlock);
tryForkUpdateScope(endBlock, a.isModified());
return a;
}
Analyzer::Action checkScope(const Token* endBlock) const {
Analyzer::Action a = analyzeScope(endBlock);
return a;
}
bool checkBranch(Branch& branch) const {
Analyzer::Action a = analyzeScope(branch.endBlock);
branch.action = a;
std::vector<ForwardTraversal> ft1 = tryForkUpdateScope(branch.endBlock, a.isModified());
const bool bail = hasGoto(branch.endBlock);
if (!a.isModified() && !bail) {
if (ft1.empty()) {
// Traverse into the branch to see if there is a conditional escape
if (!branch.escape && hasInnerReturnScope(branch.endBlock->previous(), branch.endBlock->link())) {
ForwardTraversal ft2 = fork(true);
ft2.updateScope(branch.endBlock);
if (ft2.terminate == Analyzer::Terminate::Escape) {
branch.escape = true;
branch.escapeUnknown = false;
}
}
} else {
if (ft1.front().terminate == Analyzer::Terminate::Escape) {
branch.escape = true;
branch.escapeUnknown = false;
}
}
}
return bail;
}
bool reentersLoop(Token* endBlock, const Token* condTok, const Token* stepTok) const {
if (!condTok)
return true;
if (Token::simpleMatch(condTok, ":"))
return true;
bool stepChangesCond = false;
if (stepTok) {
std::pair<const Token*, const Token*> exprToks = stepTok->findExpressionStartEndTokens();
if (exprToks.first != nullptr && exprToks.second != nullptr)
stepChangesCond |=
findExpressionChanged(condTok, exprToks.first, exprToks.second->next(), settings) != nullptr;
}
const bool bodyChangesCond = findExpressionChanged(condTok, endBlock->link(), endBlock, settings);
// Check for mutation in the condition
const bool condChanged =
nullptr != findAstNode(condTok, [&](const Token* tok) {
return isVariableChanged(tok, 0, settings);
});
const bool changed = stepChangesCond || bodyChangesCond || condChanged;
if (!changed)
return true;
ForwardTraversal ft = fork(true);
ft.updateScope(endBlock);
return ft.isConditionTrue(condTok) && bodyChangesCond;
}
Progress updateInnerLoop(Token* endBlock, Token* stepTok, Token* condTok) {
loopEnds.push_back(endBlock);
OnExit oe{[&] {
loopEnds.pop_back();
}};
if (endBlock && updateScope(endBlock) == Progress::Break)
return Break();
if (stepTok && updateRecursive(stepTok) == Progress::Break)
return Break();
if (condTok && !Token::simpleMatch(condTok, ":") && updateRecursive(condTok) == Progress::Break)
return Break();
return Progress::Continue;
}
Progress updateLoop(const Token* endToken,
Token* endBlock,
Token* condTok,
Token* initTok = nullptr,
Token* stepTok = nullptr,
bool exit = false) {
if (initTok && updateRecursive(initTok) == Progress::Break)
return Break();
const bool isDoWhile = precedes(endBlock, condTok);
bool checkThen = true;
bool checkElse = false;
if (condTok && !Token::simpleMatch(condTok, ":"))
std::tie(checkThen, checkElse) = evalCond(condTok, isDoWhile ? endBlock->previous() : nullptr);
// exiting a do while(false)
if (checkElse && exit) {
if (hasJump(endBlock)) {
if (!analyzer->lowerToPossible())
return Break(Analyzer::Terminate::Bail);
if (analyzer->isConditional() && stopUpdates())
return Break(Analyzer::Terminate::Conditional);
}
return Progress::Continue;
}
Analyzer::Action bodyAnalysis = analyzeScope(endBlock);
Analyzer::Action allAnalysis = bodyAnalysis;
Analyzer::Action condAnalysis;
if (condTok) {
condAnalysis = analyzeRecursive(condTok);
allAnalysis |= condAnalysis;
}
if (stepTok)
allAnalysis |= analyzeRecursive(stepTok);
actions |= allAnalysis;
// do while(false) is not really a loop
if (checkElse && isDoWhile &&
(condTok->hasKnownIntValue() ||
(!bodyAnalysis.isModified() && !condAnalysis.isModified() && condAnalysis.isRead()))) {
if (updateScope(endBlock) == Progress::Break)
return Break();
return updateRecursive(condTok);
}
if (allAnalysis.isInconclusive()) {
if (!analyzer->lowerToInconclusive())
return Break(Analyzer::Terminate::Bail);
} else if (allAnalysis.isModified() || (exit && allAnalysis.isIdempotent())) {
if (!analyzer->lowerToPossible())
return Break(Analyzer::Terminate::Bail);
}
if (condTok && !Token::simpleMatch(condTok, ":")) {
if (!isDoWhile || (!bodyAnalysis.isModified() && !bodyAnalysis.isIdempotent()))
if (updateRecursive(condTok) == Progress::Break)
return Break();
}
if (!checkThen && !checkElse && !isDoWhile && stopOnCondition(condTok) && stopUpdates())
return Break(Analyzer::Terminate::Conditional);
// condition is false, we don't enter the loop
if (checkElse)
return Progress::Continue;
if (checkThen || isDoWhile) {
// Since we are re-entering the loop then assume the condition is true to update the state
if (exit)
analyzer->assume(condTok, true, Analyzer::Assume::Quiet | Analyzer::Assume::Absolute);
if (updateInnerLoop(endBlock, stepTok, condTok) == Progress::Break)
return Break();
// If loop re-enters then it could be modified again
if (allAnalysis.isModified() && reentersLoop(endBlock, condTok, stepTok))
return Break(Analyzer::Terminate::Bail);
if (allAnalysis.isIncremental())
return Break(Analyzer::Terminate::Bail);
} else if (allAnalysis.isModified()) {
std::vector<ForwardTraversal> ftv = tryForkScope(endBlock, allAnalysis.isModified());
bool forkContinue = true;
for (ForwardTraversal& ft : ftv) {
if (condTok)
ft.analyzer->assume(condTok, false, Analyzer::Assume::Quiet);
if (ft.updateInnerLoop(endBlock, stepTok, condTok) == Progress::Break)
forkContinue = false;
}
if (allAnalysis.isModified() || !forkContinue) {
// TODO: Don't bail on missing condition
if (!condTok)
return Break(Analyzer::Terminate::Bail);
if (analyzer->isConditional() && stopUpdates())
return Break(Analyzer::Terminate::Conditional);
analyzer->assume(condTok, false);
}
if (forkContinue) {
for (ForwardTraversal& ft : ftv) {
if (!ft.actions.isIncremental())
ft.updateRange(endBlock, endToken);
}
}
if (allAnalysis.isIncremental())
return Break(Analyzer::Terminate::Bail);
} else {
if (updateInnerLoop(endBlock, stepTok, condTok) == Progress::Break)
return Progress::Break;
if (allAnalysis.isIncremental())
return Break(Analyzer::Terminate::Bail);
}
return Progress::Continue;
}
Progress updateLoopExit(const Token* endToken,
Token* endBlock,
Token* condTok,
Token* initTok = nullptr,
Token* stepTok = nullptr) {
return updateLoop(endToken, endBlock, condTok, initTok, stepTok, true);
}
Progress updateScope(Token* endBlock, int depth = 20)
{
if (!endBlock)
return Break();
assert(endBlock->link());
Token* ctx = endBlock->link()->previous();
if (Token::simpleMatch(ctx, ")"))
ctx = ctx->link()->previous();
if (ctx)
analyzer->updateState(ctx);
return updateRange(endBlock->link(), endBlock, depth);
}
Progress updateRange(Token* start, const Token* end, int depth = 20) {
if (depth < 0)
return Break(Analyzer::Terminate::Bail);
std::size_t i = 0;
for (Token* tok = start; precedes(tok, end); tok = tok->next()) {
Token* next = nullptr;
if (tok->index() <= i)
throw InternalError(tok, "Cyclic forward analysis.");
i = tok->index();
if (tok->link()) {
// Skip casts..
if (tok->str() == "(" && !tok->astOperand2() && tok->isCast()) {
tok = tok->link();
continue;
}
// Skip template arguments..
if (tok->str() == "<") {
tok = tok->link();
continue;
}
}
// Evaluate RHS of assignment before LHS
if (Token* assignTok = assignExpr(tok)) {
if (updateRecursive(assignTok) == Progress::Break)
return Break();
tok = nextAfterAstRightmostLeaf(assignTok);
if (!tok)
return Break();
} else if (Token::simpleMatch(tok, ") {") && Token::Match(tok->link()->previous(), "for|while (") &&
!Token::simpleMatch(tok->link()->astOperand2(), ":")) {
// In the middle of a loop structure so bail
return Break(Analyzer::Terminate::Bail);
} else if (tok->str() == ";" && tok->astParent()) {
Token* top = tok->astTop();
if (top && Token::Match(top->previous(), "for|while (") && Token::simpleMatch(top->link(), ") {")) {
Token* endCond = top->link();
Token* endBlock = endCond->linkAt(1);
Token* condTok = getCondTok(top);
Token* stepTok = getStepTok(top);
// The semicolon should belong to the initTok otherwise something went wrong, so just bail
if (tok->astOperand2() != condTok && !Token::simpleMatch(tok->astOperand2(), ";"))
return Break(Analyzer::Terminate::Bail);
if (updateLoop(end, endBlock, condTok, nullptr, stepTok) == Progress::Break)
return Break();
}
} else if (tok->str() == "break") {
const Token *scopeEndToken = findNextTokenFromBreak(tok);
if (!scopeEndToken)
return Break();
tok = skipTo(tok, scopeEndToken, end);
if (!precedes(tok, end))
return Break(Analyzer::Terminate::Escape);
if (!analyzer->lowerToPossible())
return Break(Analyzer::Terminate::Bail);
// TODO: Don't break, instead move to the outer scope
if (!tok)
return Break();
} else if (!tok->variable() && (Token::Match(tok, "%name% :") || tok->str() == "case")) {
if (!analyzer->lowerToPossible())
return Break(Analyzer::Terminate::Bail);
} else if (tok->link() && tok->str() == "}") {
const Scope* scope = tok->scope();
if (!scope)
return Break();
if (contains({Scope::eDo, Scope::eFor, Scope::eWhile, Scope::eIf, Scope::eElse, Scope::eSwitch}, scope->type)) {
const bool inElse = scope->type == Scope::eElse;
const bool inDoWhile = scope->type == Scope::eDo;
const bool inLoop = contains({Scope::eDo, Scope::eFor, Scope::eWhile}, scope->type);
Token* condTok = getCondTokFromEnd(tok);
if (!condTok)
return Break();
if (!condTok->hasKnownIntValue() || inLoop) {
if (!analyzer->lowerToPossible())
return Break(Analyzer::Terminate::Bail);
} else if (condTok->values().front().intvalue == inElse) {
return Break();
}
// Handle loop
if (inLoop) {
Token* stepTok = getStepTokFromEnd(tok);
bool checkThen, checkElse;
std::tie(checkThen, checkElse) = evalCond(condTok);
if (stepTok && !checkElse) {
if (updateRecursive(stepTok) == Progress::Break)
return Break();
if (updateRecursive(condTok) == Progress::Break)
return Break();
// Reevaluate condition
std::tie(checkThen, checkElse) = evalCond(condTok);
}
if (!checkElse) {
if (updateLoopExit(end, tok, condTok, nullptr, stepTok) == Progress::Break)
return Break();
}
}
analyzer->assume(condTok, !inElse, Analyzer::Assume::Quiet);
assert(!inDoWhile || Token::simpleMatch(tok, "} while ("));
if (Token::simpleMatch(tok, "} else {") || inDoWhile)
tok = tok->linkAt(2);
} else if (contains({Scope::eTry, Scope::eCatch}, scope->type)) {
if (!analyzer->lowerToPossible())
return Break(Analyzer::Terminate::Bail);
} else if (scope->type == Scope::eLambda) {
return Break();
}
} else if (tok->isControlFlowKeyword() && Token::Match(tok, "if|while|for (") &&
Token::simpleMatch(tok->linkAt(1), ") {")) {
if ((settings.vfOptions.maxForwardBranches > 0) && (++branchCount > settings.vfOptions.maxForwardBranches)) {
// TODO: should be logged on function-level instead of file-level
reportError(Severity::information, "normalCheckLevelMaxBranches", "Limiting analysis of branches. Use --check-level=exhaustive to analyze all branches.");
return Break(Analyzer::Terminate::Bail);
}
Token* endCond = tok->linkAt(1);
Token* endBlock = endCond->linkAt(1);
Token* condTok = getCondTok(tok);
Token* initTok = getInitTok(tok);
if (initTok && updateRecursive(initTok) == Progress::Break)
return Break();
if (Token::Match(tok, "for|while (")) {
// For-range loop
if (Token::simpleMatch(condTok, ":")) {
Token* conTok = condTok->astOperand2();
if (conTok && updateRecursive(conTok) == Progress::Break)
return Break();
bool isEmpty = false;
std::vector<MathLib::bigint> result =
analyzer->evaluate(Analyzer::Evaluate::ContainerEmpty, conTok);
if (result.empty())
analyzer->assume(conTok, false, Analyzer::Assume::ContainerEmpty);
else
isEmpty = result.front() != 0;
if (!isEmpty && updateLoop(end, endBlock, condTok) == Progress::Break)
return Break();
} else {
Token* stepTok = getStepTok(tok);
// Dont pass initTok since it was already evaluated
if (updateLoop(end, endBlock, condTok, nullptr, stepTok) == Progress::Break)
return Break();
}
tok = endBlock;
} else {
// Traverse condition
if (updateRecursive(condTok) == Progress::Break)
return Break();
Branch thenBranch{endBlock};
Branch elseBranch{endBlock->tokAt(2) ? endBlock->linkAt(2) : nullptr};
// Check if condition is true or false
std::tie(thenBranch.check, elseBranch.check) = evalCond(condTok);
if (!thenBranch.check && !elseBranch.check && stopOnCondition(condTok) && stopUpdates())
return Break(Analyzer::Terminate::Conditional);
const bool hasElse = Token::simpleMatch(endBlock, "} else {");
bool bail = false;
// Traverse then block
thenBranch.escape = isEscapeScope(endBlock, thenBranch.escapeUnknown);
if (thenBranch.check) {
thenBranch.active = true;
if (updateScope(endBlock, depth - 1) == Progress::Break)
return Break();
} else if (!elseBranch.check) {
thenBranch.active = true;
if (checkBranch(thenBranch))
bail = true;
}
// Traverse else block
if (hasElse) {
elseBranch.escape = isEscapeScope(endBlock->linkAt(2), elseBranch.escapeUnknown);
if (elseBranch.check) {
elseBranch.active = true;
const Progress result = updateScope(endBlock->linkAt(2), depth - 1);
if (result == Progress::Break)
return Break();
} else if (!thenBranch.check) {
elseBranch.active = true;
if (checkBranch(elseBranch))
bail = true;
}
tok = endBlock->linkAt(2);
} else {
tok = endBlock;
}
if (thenBranch.active)
actions |= thenBranch.action;
if (elseBranch.active)
actions |= elseBranch.action;
if (bail)
return Break(Analyzer::Terminate::Bail);
if (thenBranch.isDead() && elseBranch.isDead()) {
if (thenBranch.isModified() && elseBranch.isModified())
return Break(Analyzer::Terminate::Modified);
if (thenBranch.isConclusiveEscape() && elseBranch.isConclusiveEscape())
return Break(Analyzer::Terminate::Escape);
return Break(Analyzer::Terminate::Bail);
}
// Conditional return
if (thenBranch.active && thenBranch.isEscape() && !hasElse) {
if (!thenBranch.isConclusiveEscape()) {
if (!analyzer->lowerToInconclusive())
return Break(Analyzer::Terminate::Bail);
} else if (thenBranch.check) {
return Break();
} else {
if (analyzer->isConditional() && stopUpdates())
return Break(Analyzer::Terminate::Conditional);
analyzer->assume(condTok, false);
}
}
if (thenBranch.isInconclusive() || elseBranch.isInconclusive()) {
if (!analyzer->lowerToInconclusive())
return Break(Analyzer::Terminate::Bail);
} else if (thenBranch.isModified() || elseBranch.isModified()) {
if (!hasElse && analyzer->isConditional() && stopUpdates())
return Break(Analyzer::Terminate::Conditional);
if (!analyzer->lowerToPossible())
return Break(Analyzer::Terminate::Bail);
analyzer->assume(condTok, elseBranch.isModified());
}
}
} else if (Token::simpleMatch(tok, "try {")) {
Token* endBlock = tok->linkAt(1);
ForwardTraversal tryTraversal = fork();
tryTraversal.updateScope(endBlock, depth - 1);
bool bail = tryTraversal.actions.isModified();
if (bail) {
actions = tryTraversal.actions;
terminate = tryTraversal.terminate;
return Break();
}
while (Token::simpleMatch(endBlock, "} catch (")) {
Token* endCatch = endBlock->linkAt(2);
if (!Token::simpleMatch(endCatch, ") {"))
return Break();
endBlock = endCatch->linkAt(1);
ForwardTraversal ft = fork();
ft.updateScope(endBlock, depth - 1);
bail |= ft.terminate != Analyzer::Terminate::None || ft.actions.isModified();
}
if (bail)
return Break();
tok = endBlock;
} else if (Token::simpleMatch(tok, "do {")) {
Token* endBlock = tok->linkAt(1);
Token* condTok = Token::simpleMatch(endBlock, "} while (") ? endBlock->tokAt(2)->astOperand2() : nullptr;
if (updateLoop(end, endBlock, condTok) == Progress::Break)
return Break();
if (condTok)
tok = endBlock->linkAt(2)->next();
else
tok = endBlock;
} else if (Token::Match(tok, "assert|ASSERT (")) {
const Token* condTok = tok->next()->astOperand2();
bool checkThen, checkElse;
std::tie(checkThen, checkElse) = evalCond(condTok);
if (checkElse)
return Break();
if (!checkThen)
analyzer->assume(condTok, true, Analyzer::Assume::Quiet | Analyzer::Assume::Absolute);
} else if (Token::simpleMatch(tok, "switch (")) {
if (updateRecursive(tok->next()->astOperand2()) == Progress::Break)
return Break();
actions |= Analyzer::Action::Write; // bailout for switch scope
return Break();
} else if (Token* callTok = callExpr(tok)) {
// TODO: Dont traverse tokens a second time
if (start != callTok && tok != callTok && updateRecursive(callTok->astOperand1()) == Progress::Break)
return Break();
// Since the call could be an unknown macro, traverse the tokens as a range instead of recursively
if (!Token::simpleMatch(callTok, "( )") &&
updateRange(callTok->next(), callTok->link(), depth - 1) == Progress::Break)
return Break();
if (updateTok(callTok) == Progress::Break)
return Break();
tok = callTok->link();
if (!tok)
return Break();
} else {
if (updateTok(tok, &next) == Progress::Break)
return Break();
if (next) {
if (precedes(next, end))
tok = next->previous();
else
return Progress::Continue;
}
}
// Prevent infinite recursion
if (tok->next() == start)
break;
}
return Progress::Continue;
}
void reportError(Severity severity, const std::string& id, const std::string& msg) {
ErrorMessage::FileLocation loc(tokenList.getSourceFilePath(), 0, 0);
const ErrorMessage errmsg({std::move(loc)}, tokenList.getSourceFilePath(), severity, msg, id, Certainty::normal);
errorLogger.reportErr(errmsg);
}
static bool isFunctionCall(const Token* tok)
{
if (!Token::simpleMatch(tok, "("))
return false;
if (tok->isCast())
return false;
if (!tok->isBinaryOp())
return false;
if (Token::simpleMatch(tok->link(), ") {"))
return false;
if (isUnevaluated(tok->previous()))
return false;
return Token::Match(tok->previous(), "%name%|)|]|>");
}
static Token* assignExpr(Token* tok) {
while (tok->astParent() && astIsLHS(tok)) {
if (tok->astParent()->isAssignmentOp())
return tok->astParent();
tok = tok->astParent();
}
return nullptr;
}
static Token* callExpr(Token* tok)
{
while (tok->astParent() && astIsLHS(tok)) {
if (!Token::Match(tok, "%name%|::|<|."))
break;
if (Token::simpleMatch(tok, "<") && !tok->link())
break;
tok = tok->astParent();
}
if (isFunctionCall(tok))
return tok;
return nullptr;
}
static Token* skipTo(Token* tok, const Token* dest, const Token* end = nullptr) {
if (end && dest->index() > end->index())
return nullptr;
const int i = dest->index() - tok->index();
if (i > 0)
return tok->tokAt(dest->index() - tok->index());
return nullptr;
}
static Token* getStepTokFromEnd(Token* tok) {
if (!Token::simpleMatch(tok, "}"))
return nullptr;
Token* end = tok->link()->previous();
if (!Token::simpleMatch(end, ")"))
return nullptr;
return getStepTok(end->link());
}
};
}
Analyzer::Result valueFlowGenericForward(Token* start, const Token* end, const ValuePtr<Analyzer>& a, const TokenList& tokenList, ErrorLogger& errorLogger, const Settings& settings)
{
if (a->invalid())
return Analyzer::Result{Analyzer::Action::None, Analyzer::Terminate::Bail};
ForwardTraversal ft{a, tokenList, errorLogger, settings};
if (start)
ft.analyzer->updateState(start);
ft.updateRange(start, end);
return Analyzer::Result{ ft.actions, ft.terminate };
}
Analyzer::Result valueFlowGenericForward(Token* start, const ValuePtr<Analyzer>& a, const TokenList& tokenList, ErrorLogger& errorLogger, const Settings& settings)
{
if (Settings::terminated())
throw TerminateException();
if (a->invalid())
return Analyzer::Result{Analyzer::Action::None, Analyzer::Terminate::Bail};
ForwardTraversal ft{a, tokenList, errorLogger, settings};
(void)ft.updateRecursive(start);
return Analyzer::Result{ ft.actions, ft.terminate };
}