Fix #12861 Hang in valueFlowCondition() with huge array

clock999 · clock999 · commit d5f0f150e313 · 2025-08-24T18:08:37.000+08:00
diff --git a/lib/astutils.cpp b/lib/astutils.cpp
@@ -1013,7 +1013,7 @@ static const Token * getVariableInitExpression(const Variable * var)
 
 const Token* isInLoopCondition(const Token* tok)
 {
-    const Token* top = tok->astTop();
+    const Token* top = tok->astTop(true);
     return Token::Match(top->previous(), "for|while (") ? top : nullptr;
 }
 
@@ -2243,12 +2243,12 @@ bool isReturnScope(const Token* const endToken, const Library& library, const To
             !Token::findsimplematch(prev->link(), "break", prev)) {
             return isReturnScope(prev, library, unknownFunc, functionScope);
         }
-        if (isEscaped(prev->link()->astTop(), functionScope, library))
+        if (isEscaped(prev->link()->astTop(true), functionScope, library))
             return true;
         if (Token::Match(prev->link()->previous(), "[;{}] {"))
             return isReturnScope(prev, library, unknownFunc, functionScope);
     } else if (Token::simpleMatch(prev, ";")) {
-        if (prev->tokAt(-2) && hasNoreturnFunction(prev->tokAt(-2)->astTop(), library, unknownFunc))
+        if (prev->tokAt(-2) && hasNoreturnFunction(prev->tokAt(-2)->astTop(true), library, unknownFunc))
             return true;
         // Unknown symbol
         if (Token::Match(prev->tokAt(-2), ";|}|{ %name% ;") && prev->previous()->isIncompleteVar()) {
@@ -2257,9 +2257,9 @@ bool isReturnScope(const Token* const endToken, const Library& library, const To
             return false;
         }
         if (Token::simpleMatch(prev->previous(), ") ;") && prev->linkAt(-1) &&
-            isEscaped(prev->linkAt(-1)->astTop(), functionScope, library))
+            isEscaped(prev->linkAt(-1)->astTop(true), functionScope, library))
             return true;
-        if (isEscaped(prev->previous()->astTop(), functionScope, library))
+        if (isEscaped(prev->previous()->astTop(true), functionScope, library))
             return true;
         // return/goto statement
         prev = prev->previous();
diff --git a/lib/checkautovariables.cpp b/lib/checkautovariables.cpp
@@ -468,7 +468,7 @@ static bool isDeadTemporary(const Token* tok, const Token* expr, const Library&
     if (!isTemporary(tok, &library))
         return false;
     if (expr) {
-        if (!precedes(nextAfterAstRightmostLeaf(tok->astTop()), nextAfterAstRightmostLeaf(expr->astTop())))
+        if (!precedes(nextAfterAstRightmostLeaf(tok->astTop(true)), nextAfterAstRightmostLeaf(expr->astTop(true))))
             return false;
         const Token* parent = tok->astParent();
         if (Token::simpleMatch(parent, "{") && Token::simpleMatch(parent->astParent(), ":"))
@@ -642,7 +642,7 @@ void CheckAutoVariables::checkVarLifetimeScope(const Token * start, const Token
                     }
                     if (!ValueFlow::isLifetimeBorrowed(tok, *mSettings))
                         continue;
-                    const Token* nextTok = nextAfterAstRightmostLeaf(tok->astTop());
+                    const Token* nextTok = nextAfterAstRightmostLeaf(tok->astTop(true));
                     if (!nextTok)
                         nextTok = tok->next();
                     if (var && (!var->isLocal() || var->isStatic()) && !var->isArgument() && !(val.tokvalue && val.tokvalue->variable() && val.tokvalue->variable()->isStatic()) &&
diff --git a/lib/checkclass.cpp b/lib/checkclass.cpp
@@ -1877,7 +1877,7 @@ CheckClass::Bool CheckClass::isInverted(const Token *tok, const Token *rhs)
 
 const Token * CheckClass::getIfStmtBodyStart(const Token *tok, const Token *rhs)
 {
-    const Token *top = tok->astTop();
+    const Token *top = tok->astTop(true);
     if (Token::simpleMatch(top->link(), ") {")) {
         switch (isInverted(tok->astParent(), rhs)) {
         case Bool::BAILOUT:
@@ -2522,7 +2522,7 @@ bool CheckClass::checkConstFunc(const Scope *scope, const Function *func, Member
                         return false;
                     parent = parent->astParent();
                 }
-                const Token* const top = lhs->astTop();
+                const Token* const top = lhs->astTop(true);
                 if (top->isAssignmentOp()) {
                     if (Token::simpleMatch(top->astOperand2(), "{") && !top->astOperand2()->previous()->function()) // TODO: check usage in init list
                         return false;
diff --git a/lib/checkcondition.cpp b/lib/checkcondition.cpp
@@ -856,7 +856,7 @@ static std::string innerSmtString(const Token * tok)
 {
     if (!tok)
         return "if";
-    const Token * top = tok->astTop();
+    const Token * top = tok->astTop(true);
     if (top->str() == "(" && top->astOperand1())
         return top->astOperand1()->str();
     return top->str();
@@ -1138,7 +1138,7 @@ static std::string conditionString(const Token * tok)
 }
 
 static bool isIfConstexpr(const Token* tok) {
-    const Token* const top = tok->astTop();
+    const Token* const top = tok->astTop(true);
     return Token::simpleMatch(top->astOperand1(), "if") && top->astOperand1()->isConstexpr();
 }
 
@@ -1835,7 +1835,7 @@ void CheckCondition::checkDuplicateConditionalAssign()
                 continue;
             if (!blockTok->next())
                 continue;
-            const Token *assignTok = blockTok->next()->astTop();
+            const Token *assignTok = blockTok->next()->astTop(true);
             if (!Token::simpleMatch(assignTok, "="))
                 continue;
             if (nextAfterAstRightmostLeaf(assignTok) != blockTok->link()->previous())
diff --git a/lib/checkfunctions.cpp b/lib/checkfunctions.cpp
@@ -641,7 +641,7 @@ void CheckFunctions::checkLibraryMatchFunctions()
         if (tok->function())
             continue;
 
-        if (Token::simpleMatch(tok->astTop(), "throw"))
+        if (Token::simpleMatch(tok->astTop(true), "throw"))
             continue;
 
         if (Token::simpleMatch(tok->astParent(), ".")) {
diff --git a/lib/checkleakautovar.cpp b/lib/checkleakautovar.cpp
@@ -985,7 +985,7 @@ void CheckLeakAutoVar::changeAllocStatus(VarInfo &varInfo, const VarInfo::AllocI
             var->second.type = allocation.type;
             var->second.allocTok = allocation.allocTok;
         }
-    } else if (allocation.status != VarInfo::NOALLOC && allocation.status != VarInfo::OWNED && !Token::simpleMatch(tok->astTop(), "return")) {
+    } else if (allocation.status != VarInfo::NOALLOC && allocation.status != VarInfo::OWNED && !Token::simpleMatch(tok->astTop(true), "return")) {
         auto& allocInfo = alloctype[arg->varId()];
         allocInfo.status = VarInfo::DEALLOC;
         allocInfo.allocTok = tok;
diff --git a/lib/checkmemoryleak.cpp b/lib/checkmemoryleak.cpp
@@ -1012,7 +1012,7 @@ void CheckMemoryLeakNoVar::checkForUnreleasedInputArgument(const Scope *scope)
             tok2 = tok2->astParent();
         if (Token::Match(tok2, "%assign%")) // TODO: check if function returns allocated resource
             continue;
-        if (Token::simpleMatch(tok->astTop(), "return"))
+        if (Token::simpleMatch(tok->astTop(true), "return"))
             continue;
 
         const std::string& functionName = tok->str();
diff --git a/lib/checkother.cpp b/lib/checkother.cpp
@@ -2241,7 +2241,7 @@ static bool isConstTop(const Token *tok)
     if (!tok->astParent())
         return true;
     if (Token::simpleMatch(tok->astParent(), ";") &&
-        Token::Match(tok->astTop()->previous(), "for|if (") && Token::simpleMatch(tok->astTop()->astOperand2(), ";")) {
+        Token::Match(tok->astTop(true)->previous(), "for|if (") && Token::simpleMatch(tok->astTop(true)->astOperand2(), ";")) {
         if (Token::simpleMatch(tok->astParent()->astParent(), ";"))
             return tok->astParent()->astOperand2() == tok;
         return tok->astParent()->astOperand1() == tok;
@@ -2272,7 +2272,7 @@ void CheckOther::checkIncompleteStatement()
             continue;
         if (!isConstTop(tok))
             continue;
-        if (tok->str() == "," && Token::simpleMatch(tok->astTop()->previous(), "for ("))
+        if (tok->str() == "," && Token::simpleMatch(tok->astTop(true)->previous(), "for ("))
             continue;
 
         // Do not warn for statement when both lhs and rhs has side effects:
@@ -2540,7 +2540,7 @@ static const Token * getSingleExpressionInBlock(const Token * tok)
 {
     if (!tok)
         return nullptr;
-    const Token * top = tok->astTop();
+    const Token * top = tok->astTop(true);
     const Token * nextExpression = nextAfterAstRightmostLeaf(top);
     if (!Token::simpleMatch(nextExpression, "; }"))
         return nullptr;
diff --git a/lib/checkstl.cpp b/lib/checkstl.cpp
@@ -1649,7 +1649,7 @@ static const Token* skipLocalVars(const Token* const tok)
         return skipLocalVars(tok->next());
 
     if (tok->isAssignmentOp()) {
-        const Token *top = tok->astTop();
+        const Token *top = tok->astTop(true);
         const Token *varTok = top->astOperand1();
         const Variable *var = varTok->variable();
         if (!var)
@@ -1667,7 +1667,7 @@ static const Token* skipLocalVars(const Token* const tok)
 static const Token *findInsertValue(const Token *tok, const Token *containerTok, const Token *keyTok, const Settings &settings)
 {
     const Token *startTok = skipLocalVars(tok);
-    const Token *top = startTok->astTop();
+    const Token *top = startTok->astTop(true);
 
     const Token *icontainerTok = nullptr;
     const Token *ikeyTok = nullptr;
diff --git a/lib/forwardanalyzer.cpp b/lib/forwardanalyzer.cpp
@@ -610,7 +610,7 @@ namespace {
                     // In the middle of a loop structure so bail
                     return Break(Analyzer::Terminate::Bail);
                 } else if (tok->str() == ";" && tok->astParent()) {
-                    Token* top = tok->astTop();
+                    Token* top = tok->astTop(true);
                     if (Token::Match(top->previous(), "for|while (") && Token::simpleMatch(top->link(), ") {")) {
                         Token* endCond = top->link();
                         Token* endBlock = endCond->linkAt(1);
diff --git a/lib/library.cpp b/lib/library.cpp
@@ -1338,7 +1338,7 @@ bool Library::isScopeNoReturn(const Token *end, std::string *unknownFunc) const
         unknownFunc->clear();
 
     if (Token::Match(end->tokAt(-2), "!!{ ; }")) {
-        const Token *lastTop = end->tokAt(-2)->astTop();
+        const Token *lastTop = end->tokAt(-2)->astTop(true);
         if (Token::simpleMatch(lastTop, "<<") &&
             Token::simpleMatch(lastTop->astOperand1(), "(") &&
             Token::Match(lastTop->astOperand1()->previous(), "%name% ("))
@@ -1349,7 +1349,7 @@ bool Library::isScopeNoReturn(const Token *end, std::string *unknownFunc) const
         return false;
 
     const Token *funcname = end->linkAt(-2)->previous();
-    if (funcname->isCpp() && funcname->astTop()->str() == "throw")
+    if (funcname->isCpp() && funcname->astTop(true)->str() == "throw")
         return true;
     const Token *start = funcname;
     if (Token::Match(funcname->tokAt(-3),"( * %name% )")) {
diff --git a/lib/programmemory.cpp b/lib/programmemory.cpp
@@ -532,7 +532,7 @@ void ProgramMemoryState::assume(const Token* tok, bool b, bool isEmpty)
     else
         programMemoryParseCondition(pm, tok, nullptr, settings, b);
     const Token* origin = tok;
-    const Token* top = tok->astTop();
+    const Token* top = tok->astTop(true);
     if (Token::Match(top->previous(), "for|while|if (") && !Token::simpleMatch(tok->astParent(), "?")) {
         origin = top->link()->next();
         if (!b && origin->link()) {
@@ -1750,7 +1750,7 @@ namespace {
             if (!scope->bodyStart)
                 return {unknown()};
             for (const Token* tok = scope->bodyStart->next(); precedes(tok, scope->bodyEnd); tok = tok->next()) {
-                const Token* top = tok->astTop();
+                const Token* top = tok->astTop(true);
 
                 if (Token::simpleMatch(top, "return") && top->astOperand1())
                     return {execute(top->astOperand1())};
diff --git a/lib/reverseanalyzer.cpp b/lib/reverseanalyzer.cpp
@@ -295,7 +295,7 @@ namespace {
                     if (!condTok)
                         break;
                     Analyzer::Action condAction = analyzeRecursive(condTok);
-                    const bool inLoop = Token::Match(condTok->astTop()->previous(), "for|while (");
+                    const bool inLoop = Token::Match(condTok->astTop(true)->previous(), "for|while (");
                     // Evaluate condition of for and while loops first
                     if (inLoop) {
                         if (Token::findmatch(tok->link(), "goto|break", tok))
diff --git a/lib/symboldatabase.cpp b/lib/symboldatabase.cpp
@@ -5369,7 +5369,7 @@ const Enumerator * SymbolDatabase::findEnumerator(const Token * tok, std::set<st
             return nullptr;
 
         if (tok->scope()->type == ScopeType::eGlobal) {
-            const Token* astTop = tok->astTop();
+            const Token* astTop = tok->astTop(true);
             if (Token::simpleMatch(astTop, ":") && Token::simpleMatch(astTop->astOperand1(), "(")) { // ctor init list
                 const Token* ctor = astTop->astOperand1()->previous();
                 if (ctor && ctor->function() && ctor->function()->nestedIn)
diff --git a/lib/token.cpp b/lib/token.cpp
@@ -1437,7 +1437,7 @@ void Token::astOperand1(Token *tok)
         mImpl->mAstOperand1->astParent(nullptr);
     // goto parent operator
     if (tok) {
-        tok = tok->astTop();
+        tok = tok->astTop(false);
         tok->astParent(this);
     }
     mImpl->mAstOperand1 = tok;
@@ -1449,7 +1449,7 @@ void Token::astOperand2(Token *tok)
         mImpl->mAstOperand2->astParent(nullptr);
     // goto parent operator
     if (tok) {
-        tok = tok->astTop();
+        tok = tok->astTop(false);
         tok->astParent(this);
     }
     mImpl->mAstOperand2 = tok;
diff --git a/lib/token.h b/lib/token.h
@@ -27,6 +27,7 @@
 #include "templatesimplifier.h"
 #include "utils.h"
 #include "vfvalue.h"
+#include "tokenlist.h"
 
 #include <algorithm>
 #include <cassert>
@@ -88,6 +89,7 @@ struct TokenImpl {
     Token* mAstOperand1{};
     Token* mAstOperand2{};
     Token* mAstParent{};
+    Token* mAstTop{};
 
     // symbol database information
     const Scope* mScope{};
@@ -1531,17 +1533,31 @@ class CPPCHECKLIB Token {
         return nullptr;
 
     }
-    RET_NONNULL Token *astTop() {
+    /** If the ast tree has not been created, pls make sure to use cache=false,
+        as the real top has not been identified finally. */
+    RET_NONNULL Token *astTop(bool cache) {
         Token *ret = this;
+        if (cache && mImpl->mAstTop) {
+            return mImpl->mAstTop;
+        }
         while (ret->mImpl->mAstParent)
             ret = ret->mImpl->mAstParent;
+        if (cache) {
+            mImpl->mAstTop = ret;
+        }
         return ret;
     }
 
-    RET_NONNULL const Token *astTop() const {
+    RET_NONNULL const Token *astTop(bool cache) const {
         const Token *ret = this;
+        if (cache && mImpl->mAstTop) {
+            return mImpl->mAstTop;
+        }
         while (ret->mImpl->mAstParent)
             ret = ret->mImpl->mAstParent;
+        if (cache) {
+            mImpl->mAstTop = const_cast<Token *>(ret);
+        }
         return ret;
     }
 
diff --git a/lib/tokenlist.cpp b/lib/tokenlist.cpp
@@ -1728,7 +1728,7 @@ static Token * createAstAtToken(Token *tok)
         }
 
         if (init != semicolon1)
-            semicolon1->astOperand1(init->astTop());
+            semicolon1->astOperand1(init->astTop(false));
         tok->next()->astOperand1(tok);
         tok->next()->astOperand2(semicolon1);
 
diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
@@ -1575,7 +1575,7 @@ static bool isConditionKnown(const Token* tok, bool then)
     const Token* parent = tok->astParent();
     while (parent && (parent->str() == op || parent->str() == "!" || parent->isCast()))
         parent = parent->astParent();
-    const Token* top = tok->astTop();
+    const Token* top = tok->astTop(true);
     if (Token::Match(top->previous(), "if|while|for ("))
         return parent == top || Token::simpleMatch(parent, ";");
     return parent && parent->str() != op;
@@ -2105,7 +2105,7 @@ const Token* ValueFlow::getEndOfExprScope(const Token* tok, const Scope* default
                 if (!end || (smallest ? precedes(varEnd, end) : succeeds(varEnd, end)))
                     end = varEnd;
 
-                const Token* top = var->nameToken()->astTop();
+                const Token* top = var->nameToken()->astTop(true);
                 if (Token::simpleMatch(top->tokAt(-1), "if (")) { // variable declared in if (...)
                     const Token* elseTok = top->link()->linkAt(1);
                     if (Token::simpleMatch(elseTok, "} else {") && tok->scope()->isNestedIn(elseTok->tokAt(2)->scope()))
@@ -4599,7 +4599,7 @@ struct ConditionHandler {
                 if (Token::Match(tok, ":|;|,"))
                     continue;
 
-                const Token* top = tok->astTop();
+                const Token* top = tok->astTop(true);
 
                 if (!Token::Match(top->previous(), "if|while|for (") && !Token::Match(tok->astParent(), "&&|%oror%|?|!"))
                     continue;
@@ -4633,7 +4633,7 @@ struct ConditionHandler {
             if (tok->hasKnownIntValue())
                 return;
 
-            Token* top = tok->astTop();
+            Token* top = tok->astTop(true);
 
             if (Token::Match(top, "%assign%"))
                 return;
@@ -4852,7 +4852,7 @@ struct ConditionHandler {
                 }
             }
 
-            Token* top = condTok->astTop();
+            Token* top = condTok->astTop(true);
 
             if (top->previous()->isExpandedMacro()) {
                 for (std::list<ValueFlow::Value>* values : {&thenValues, &elseValues}) {
@@ -5414,7 +5414,7 @@ static void valueFlowForLoopSimplify(Token* const bodyStart,
         }
 
         if (Token::Match(tok2, "%oror%|&&")) {
-            const ProgramMemory programMemory(getProgramMemory(tok2->astTop(), expr, ValueFlow::Value(value), settings));
+            const ProgramMemory programMemory(getProgramMemory(tok2->astTop(true), expr, ValueFlow::Value(value), settings));
             if ((tok2->str() == "&&" && !conditionIsTrue(tok2->astOperand1(), programMemory, settings)) ||
                 (tok2->str() == "||" && !conditionIsFalse(tok2->astOperand1(), programMemory, settings))) {
                 // Skip second expression..
@@ -5439,11 +5439,11 @@ static void valueFlowForLoopSimplify(Token* const bodyStart,
 
         if ((tok2->str() == "&&" &&
              conditionIsFalse(tok2->astOperand1(),
-                              getProgramMemory(tok2->astTop(), expr, ValueFlow::Value(value), settings),
+                              getProgramMemory(tok2->astTop(true), expr, ValueFlow::Value(value), settings),
                               settings)) ||
             (tok2->str() == "||" &&
              conditionIsTrue(tok2->astOperand1(),
-                             getProgramMemory(tok2->astTop(), expr, ValueFlow::Value(value), settings),
+                             getProgramMemory(tok2->astTop(true), expr, ValueFlow::Value(value), settings),
                              settings)))
             break;
 
@@ -6799,7 +6799,7 @@ static void valueFlowContainerSize(const TokenList& tokenlist,
                 !Token::Match(nameToken, "%name% ("))
                 continue;
         }
-        if (Token::Match(nameToken->astTop()->previous(), "for|while"))
+        if (Token::Match(nameToken->astTop(true)->previous(), "for|while"))
             known = !isVariableChanged(var, settings);
         std::vector<ValueFlow::Value> values{ValueFlow::Value{size}};
         values.back().valueType = ValueFlow::Value::ValueType::CONTAINER_SIZE;
diff --git a/test/testtokenize.cpp b/test/testtokenize.cpp

Original file line number	Diff line number	Diff line change
`@@ -985,7 +985,7 @@ void CheckLeakAutoVar::changeAllocStatus(VarInfo &varInfo, const VarInfo::AllocI`
`985`	`985`	`var->second.type = allocation.type;`
`986`	`986`	`var->second.allocTok = allocation.allocTok;`
`987`	`987`	`}`
`988`		`- } else if (allocation.status != VarInfo::NOALLOC && allocation.status != VarInfo::OWNED && !Token::simpleMatch(tok->astTop(), "return")) {`
	`988`	`+ } else if (allocation.status != VarInfo::NOALLOC && allocation.status != VarInfo::OWNED && !Token::simpleMatch(tok->astTop(true), "return")) {`
`989`	`989`	`auto& allocInfo = alloctype[arg->varId()];`
`990`	`990`	`allocInfo.status = VarInfo::DEALLOC;`
`991`	`991`	`allocInfo.allocTok = tok;`