Fix #12861 Hang in valueFlowCondition() with huge array

Author: clock999

lib/token.cpp

@@ -1451,7 +1451,9 @@ void Token::astOperand1(Token *tok)
         mImpl->mAstOperand1->astParent(nullptr);
     // goto parent operator
     if (tok) {
-        tok = tok->astTop();
+        while (tok->mImpl->mAstParent) {
+            tok = tok->mImpl->mAstParent;
+        }
         tok->astParent(this);
     }
     mImpl->mAstOperand1 = tok;
@@ -1463,7 +1465,9 @@ void Token::astOperand2(Token *tok)
         mImpl->mAstOperand2->astParent(nullptr);
     // goto parent operator
     if (tok) {
-        tok = tok->astTop();
+        while (tok->mImpl->mAstParent) {
+            tok = tok->mImpl->mAstParent;
+        }
         tok->astParent(this);
     }
     mImpl->mAstOperand2 = tok;

lib/token.h

@@ -117,6 +117,7 @@ class CPPCHECKLIB Token {
         Token* mAstOperand1{};
         Token* mAstOperand2{};
         Token* mAstParent{};
+        Token* mAstTop{};
 
         // symbol database information
         const Scope* mScope{};
@@ -1598,15 +1599,23 @@ class CPPCHECKLIB Token {
     }
     RET_NONNULL Token *astTop() {
         Token *ret = this;
+        if (mImpl->mAstTop) {
+            return mImpl->mAstTop;
+        }
         while (ret->mImpl->mAstParent)
             ret = ret->mImpl->mAstParent;
+        mImpl->mAstTop = ret;
         return ret;
     }
 
     RET_NONNULL const Token *astTop() const {
         const Token *ret = this;
+        if (mImpl->mAstTop) {
+            return mImpl->mAstTop;
+        }
         while (ret->mImpl->mAstParent)
             ret = ret->mImpl->mAstParent;
+        mImpl->mAstTop = const_cast<Token *>(ret);
         return ret;
     }
 

lib/tokenlist.cpp

@@ -1743,8 +1743,13 @@ static Token * createAstAtToken(Token *tok)
             semicolon1->astOperand2(state2.op.top());
         }
 
-        if (init != semicolon1)
-            semicolon1->astOperand1(init->astTop());
+        if (init != semicolon1) {
+            Token * top = init;
+            while (top->astParent()) {
+                top = top->astParent();
+            }
+            semicolon1->astOperand1(top);
+        }
         tok->next()->astOperand1(tok);
         tok->next()->astOperand2(semicolon1);