Fix #12807 (dump file: provide alignas expressions)

Author: danmar

lib/token.h

@@ -122,6 +122,9 @@ struct TokenImpl {
     };
     CppcheckAttributes* mCppcheckAttributes{};
 
+    // alignas expressions
+    std::string mAttributeAlignas;
+
     // For memoization, to speed up parsing of huge arrays #8897
     enum class Cpp11init { UNKNOWN, CPP11INIT, NOINIT } mCpp11init = Cpp11init::UNKNOWN;
 
@@ -545,6 +548,19 @@ class CPPCHECKLIB Token {
     void isAttributeMaybeUnused(const bool value) {
         setFlag(fIsAttributeMaybeUnused, value);
     }
+    std::string getAttributeAlignas() const {
+        return mImpl->mAttributeAlignas;
+    }
+    bool hasAttributeAlignas() const {
+        return !mImpl->mAttributeAlignas.empty();
+    }
+    void setAttributeAlignas(const std::string& a) {
+        if (a.empty() || mImpl->mAttributeAlignas.empty())
+            mImpl->mAttributeAlignas = a;
+        else if (a != mImpl->mAttributeAlignas)
+            // mismatching alignas expressions, add both
+            mImpl->mAttributeAlignas += "\n" + a;
+    }
     void setCppcheckAttribute(TokenImpl::CppcheckAttributes::Type type, MathLib::bigint value) {
         mImpl->setCppcheckAttribute(type, value);
     }

lib/tokenize.cpp

@@ -6044,6 +6044,8 @@ void Tokenizer::dump(std::ostream &out) const
             outs += " isAttributeMaybeUnused=\"true\"";
         if (tok->isAttributeUnused())
             outs += " isAttributeUnused=\"true\"";
+        if (tok->hasAttributeAlignas())
+            outs += " alignas=\"" + ErrorLogger::toxml(tok->getAttributeAlignas()) + "\"";
         if (tok->link()) {
             outs += " link=\"";
             outs += id_string(tok->link());
@@ -9353,6 +9355,20 @@ void Tokenizer::simplifyCPPAttribute()
             }
         } else {
             if (Token::simpleMatch(tok, "alignas (")) {
+                Token* atok = nullptr;
+                if (Token::Match(tok->previous(), "%name%"))
+                    atok = tok->previous();
+                else {
+                    while (isCPPAttribute(atok) || isAlignAttribute(atok))
+                        atok = skipCPPOrAlignAttribute(atok)->next();
+                }
+                if (atok) {
+                    std::string a;
+                    for (const Token* t = tok->tokAt(2); t && t->str() != ")"; t = t->next())
+                        a += " " + t->str();
+                    if (a.size() > 1)
+                        atok->setAttributeAlignas(a.substr(1));
+                }
                 // alignment requirements could be checked here
             }
         }