optimized Library::detectContainerInternal() a bit (#5333)

Scanning `cli/filelister.cpp` with `DISABLE_VALUEFLOW=1` and
`--enable=all -Ilib -D__GNUC__`

Clang 15 `111,300,996` -> `106,883,955`
GCC 13 `110,555,879` -> `105,983,608`

Author: firewave

lib/library.cpp

@@ -419,7 +419,7 @@ Library::Error Library::load(const tinyxml2::XMLDocument &doc)
 
             const char* const inherits = node->Attribute("inherits");
             if (inherits) {
-                const std::map<std::string, Container>::const_iterator i = containers.find(inherits);
+                const std::unordered_map<std::string, Container>::const_iterator i = containers.find(inherits);
                 if (i != containers.end())
                     container = i->second; // Take values from parent and overwrite them if necessary
                 else
@@ -1158,8 +1158,17 @@ bool Library::isScopeNoReturn(const Token *end, std::string *unknownFunc) const
     return false;
 }
 
-const Library::Container* Library::detectContainerInternal(const Token* typeStart, DetectContainer detect, bool* isIterator, bool withoutStd) const
+const Library::Container* Library::detectContainerInternal(const Token* const typeStart, DetectContainer detect, bool* isIterator, bool withoutStd) const
 {
+    const Token* firstLinkedTok = nullptr;
+    for (const Token* tok = typeStart; tok && !tok->varId(); tok = tok->next()) {
+        if (!tok->link())
+            continue;
+
+        firstLinkedTok = tok;
+        break;
+    }
+
     for (const std::pair<const std::string, Library::Container> & c : containers) {
         const Container& container = c.second;
         if (container.startPattern.empty())
@@ -1177,23 +1186,22 @@ const Library::Container* Library::detectContainerInternal(const Token* typeStar
             return &container;
         }
 
-        for (const Token* tok = typeStart; tok && !tok->varId(); tok = tok->next()) {
-            if (!tok->link())
-                continue;
+        if (!firstLinkedTok)
+            continue;
 
-            const bool matchedStartPattern = Token::Match(typeStart, container.startPattern2.c_str() + offset);
+        const bool matchedStartPattern = Token::Match(typeStart, container.startPattern2.c_str() + offset);
+        if (!matchedStartPattern)
+            continue;
 
-            if (detect != ContainerOnly && matchedStartPattern && Token::Match(tok->link(), container.itEndPattern.c_str())) {
-                if (isIterator)
-                    *isIterator = true;
-                return &container;
-            }
-            if (detect != IteratorOnly && matchedStartPattern && Token::Match(tok->link(), container.endPattern.c_str())) {
-                if (isIterator)
-                    *isIterator = false;
-                return &container;
-            }
-            break;
+        if (detect != ContainerOnly && Token::Match(firstLinkedTok->link(), container.itEndPattern.c_str())) {
+            if (isIterator)
+                *isIterator = true;
+            return &container;
+        }
+        if (detect != IteratorOnly && Token::Match(firstLinkedTok->link(), container.endPattern.c_str())) {
+            if (isIterator)
+                *isIterator = false;
+            return &container;
         }
     }
     return nullptr;

lib/library.h

@@ -282,7 +282,7 @@ class CPPCHECKLIB Library {
         static Yield yieldFrom(const std::string& yieldName);
         static Action actionFrom(const std::string& actionName);
     };
-    std::map<std::string, Container> containers;
+    std::unordered_map<std::string, Container> containers;
     const Container* detectContainer(const Token* typeStart) const;
     const Container* detectIterator(const Token* typeStart) const;
     const Container* detectContainerOrIterator(const Token* typeStart, bool* isIterator = nullptr, bool withoutStd = false) const;