ClangImport: improved location parsing / better handling for "prologue" TypedefDecls

lib/clangimport.cpp

@@ -326,16 +326,16 @@ namespace clangimport {
         std::string nodeType;
         std::vector<AstNodePtr> children;
 
+        bool isPrologueTypedefDecl() const;
         void setLocations(TokenList &tokenList, int file, int line, int col);
 
         void dumpAst(int num = 0, int indent = 0) const;
         void createTokens1(TokenList &tokenList) {
             //dumpAst(); // TODO: reactivate or remove
+            if (isPrologueTypedefDecl())
+                return;
             if (!tokenList.back()) {
                 setLocations(tokenList, 0, 1, 1);
-                // FIXME: treat as C++ if no filename (i.e. no lang) is specified for now
-                if (tokenList.getSourceFilePath().empty())
-                    tokenList.setLang(Standards::Language::CPP);
             }
             else
                 setLocations(tokenList, tokenList.back()->fileIndex(), tokenList.back()->linenr(), 1);
@@ -502,9 +502,43 @@ void clangimport::AstNode::dumpAst(int num, int indent) const
     }
 }
 
+bool clangimport::AstNode::isPrologueTypedefDecl() const
+{
+    // these TypedefDecl are included in *any* AST dump and we should ignore them as they should not be of interest to us
+    // see https://github.com/llvm/llvm-project/issues/120228#issuecomment-2549212109 for an explanation
+    if (nodeType != TypedefDecl)
+        return false;
+
+    // TODO: use different values to indicate "<invalid sloc>"?
+    if (mFile != 0 || mLine != 1 || mCol != 1)
+        return false;
+
+    // TODO: match without using children
+    if (children.empty())
+        return false;
+
+    if (children[0].get()->mExtTokens.size() < 2)
+        return false;
+
+    const auto& type = children[0].get()->mExtTokens[1];
+    if (type == "'__int128'" ||
+        type == "'unsigned __int128'" ||
+        type == "'struct __NSConstantString_tag'" ||
+        type == "'char *'" ||
+        type == "'struct __va_list_tag[1]'")
+    {
+        // NOLINTNEXTLINE(readability-simplify-boolean-expr)
+        return true;
+    }
+
+    return false;
+}
+
 void clangimport::AstNode::setLocations(TokenList &tokenList, int file, int line, int col)
 {
-    for (const std::string &ext: mExtTokens) {
+    if (mExtTokens.size() >= 2)
+    {
+        const std::string &ext = mExtTokens[1];
         if (startsWith(ext, "<col:"))
             col = strToInt<int>(ext.substr(5, ext.find_first_of(",>", 5) - 5));
         else if (startsWith(ext, "<line:")) {
@@ -521,6 +555,12 @@ void clangimport::AstNode::setLocations(TokenList &tokenList, int file, int line
                 file = tokenList.appendFileIfNew(ext.substr(1, sep1 - 1));
                 line = strToInt<int>(ext.substr(sep1 + 1, sep2 - sep1 - 1));
             }
+            else {
+                // "<invalid sloc>" are encountered in every AST dump by some built-in TypedefDecl
+                // an completely empty location block was encountered with a CompoundStmt
+                if (ext != "<<invalid sloc>" && ext != "<>")
+                    throw InternalError(nullptr, "invalid AST location: " + ext, InternalError::AST);
+            }
         }
     }
     mFile = file;