ignore already seen locations in compiler plugins

Change-Id: Icba8dfa61aee7237af569b2414b1cf4ce93ca476

2 files changed, 16 insertions, 6 deletions

diff --git a/compilerplugins/clang/plugin.cxx b/compilerplugins/clang/plugin.cxx
index 85bd69625b09..bfcec730003d 100644
--- a/compilerplugins/clang/plugin.cxx
+++ b/compilerplugins/clang/plugin.cxx
@@ -56,12 +56,21 @@ bool Plugin::ignoreLocation( SourceLocation loc )
     const char* bufferName = compiler.getSourceManager().getPresumedLoc( expansionLoc ).getFilename();
     if( bufferName == NULL )
         return true;
-    if( strncmp( bufferName, OUTDIR, strlen( OUTDIR )) == 0
-        || strncmp( bufferName, WORKDIR, strlen( WORKDIR )) == 0
-        || strncmp( bufferName, BUILDDIR, strlen( BUILDDIR )) == 0
-        || strncmp( bufferName, SRCDIR, strlen( SRCDIR )) == 0 )
-        return false; // ok
-    return true;
+    if( strncmp( bufferName, OUTDIR, strlen( OUTDIR )) != 0
+        && strncmp( bufferName, WORKDIR, strlen( WORKDIR )) != 0
+        && strncmp( bufferName, BUILDDIR, strlen( BUILDDIR )) != 0
+        && strncmp( bufferName, SRCDIR, strlen( SRCDIR )) != 0 )
+        return true; // not in LO sources
+    // Sometimes a VisitXXX function may be called more than once for one source location.
+    // This can happen e.g. with a default argument for a function, if it involves constructing
+    // a temporary, then this temporary will be constructed whenever the function is called
+    // and the default argument is needed. As this would mean processing the same piece of code
+    // more than once, and thus possibly modifying the source code more than once, just
+    // ignore an already seen location.
+    if( alreadySeen.find( loc ) != alreadySeen.end())
+        return true;
+    alreadySeen.insert( loc );
+    return false;
     }
 
 void Plugin::registerPlugin( Plugin* (*create)( CompilerInstance&, Rewriter& ), const char* optionName, bool isRewriter )
diff --git a/compilerplugins/clang/plugin.hxx b/compilerplugins/clang/plugin.hxx
index da336818cccb..52f6273e16e2 100644
--- a/compilerplugins/clang/plugin.hxx
+++ b/compilerplugins/clang/plugin.hxx
@@ -53,6 +53,7 @@ class Plugin
         bool ignoreLocation( const Decl* decl );
         bool ignoreLocation( const Stmt* stmt );
         CompilerInstance& compiler;
+        set< SourceLocation > alreadySeen;
     private:
         static void registerPlugin( Plugin* (*create)( CompilerInstance&, Rewriter& ), const char* optionName, bool isRewriter );
         template< typename T > static Plugin* createHelper( CompilerInstance& compiler, Rewriter& rewriter );