Improved logic for detection of insertion point

This will handle cases like:

   Task t(                // Line 1
   &callbackFunc          // Line 2: undeclared identifier
   );                     // Line 3
   void callbackFunc() {} // Line 4

since the parsed token are:
   Task
   void callbackFunc()

the previous logic will insert the prototypes berween line 3 and 4,
because callbackFunc is first token that comes after the undeclared
identifier.
After this patch, the current token position is cached so it can be
used if the next token comes after the first undeclared identifier.

Author: cmaglie

main.cpp

@@ -79,7 +79,7 @@ class INOPreprocessorMatcherCallback : public MatchFinder::MatchCallback {
 
     void run(const MatchFinder::MatchResult &match) override {
         ASTContext *ctx = match.Context;
-        SourceManager *sm = &ctx->getSourceManager();
+        SourceManager &sm = ctx->getSourceManager();
 
         const FunctionDecl *f = match.Nodes.getNodeAs<FunctionDecl>("function_decl");
         if (f) {
@@ -102,14 +102,9 @@ class INOPreprocessorMatcherCallback : public MatchFinder::MatchCallback {
                 return;
             }
 
+            detectInsertionPoint(sm, begin, end);
             if (!insertionPointFound) {
-                insertionPointFound = true;
-                insertionPoint = begin;
-                presumedInsertionPoint = sm->getPresumedLoc(begin, true);
-                if (debugOutput) {
-                    outs() << "  !! Insertion point set to ";
-                    outs() << begin.getSpellingLineNumber() << ":" << begin.getSpellingColumnNumber() << "\n";
-                }
+                return;
             }
 
             if (outputOnlyNeededPrototypes) {
@@ -124,7 +119,7 @@ class INOPreprocessorMatcherCallback : public MatchFinder::MatchCallback {
             }
 
             // Extract line pragma for prototype insertion
-            writeLineInfo(sm->getPresumedLoc(loc, true));
+            writeLineInfo(sm.getPresumedLoc(loc, true));
 
             // Extract prototype from function using the pretty printer
             // and stopping at the first open curly brace "{"
@@ -142,17 +137,53 @@ class INOPreprocessorMatcherCallback : public MatchFinder::MatchCallback {
 
         const VarDecl *v = match.Nodes.getNodeAs<VarDecl>("var_decl");
         if (v) {
-            auto loc = ctx->getFullLoc(v->getLocStart());
+            FullSourceLoc loc = ctx->getFullLoc(v->getLocStart());
+            SourceRange r = v->getSourceRange();
+            FullSourceLoc begin = ctx->getFullLoc(r.getBegin());
+            FullSourceLoc end = ctx->getFullLoc(r.getEnd());
+
             if (debugOutput) {
                 outs() << "Variable " << v->getName() << " declared at ";
-                outs() << loc.getSpellingLineNumber() << ":" << loc.getSpellingColumnNumber() << "\n";
+                outs() << loc.getSpellingLineNumber() << ":" << loc.getSpellingColumnNumber();
+                outs() << " (range " << begin.getSpellingLineNumber() << ":" << begin.getSpellingColumnNumber();
+                outs() << " to " << end.getSpellingLineNumber() << ":" << end.getSpellingColumnNumber() << ")\n";
             }
             if (v->getParentFunctionOrMethod()) {
                 if (debugOutput) {
                     outs() << "  Variable is not top level, ignoring.\n";
                 }
                 return;
             }
+
+            detectInsertionPoint(sm, begin, end);
+        }
+    }
+
+    void detectInsertionPoint(SourceManager &sm, FullSourceLoc &begin, FullSourceLoc &end) {
+        if (insertionPointFound)return;
+
+        FullSourceLoc first = undeclaredIdentifiers.front()->location;
+
+        if (first.isBeforeInTranslationUnitThan(begin)) {
+            if (debugOutput) {
+                outs() << "  !! Insertion point found!\n";
+            }
+            insertionPointFound = true;
+            return;
+        }
+
+        insertionPoint = begin;
+        presumedInsertionPoint = sm.getPresumedLoc(begin, true);
+        if (debugOutput) {
+            outs() << "  Insertion point pushed to ";
+            outs() << begin.getSpellingLineNumber() << ":" << begin.getSpellingColumnNumber() << "\n";
+        }
+
+        if (first.isBeforeInTranslationUnitThan(end)) {
+            if (debugOutput) {
+                outs() << "  !! Insertion point found!\n";
+            }
+            insertionPointFound = true;
         }
     }