[cfe-dev] operator new

[Михаил]

Hi.

Is there a way to understand what class(struct) was created by operator new by analysing generated bytecode? 

I thought that after   %call = tail call noalias i8* @_Znwj(i32 <size>)  is goes bitcast of %call to need struct, but for next example it is wrong.

For exampe I have a function:

Query* WildcardQuery::clone() const{
	return _CLNEW WildcardQuery(*this);
}

And bytecode for this:

define %"class.lucene::search::Query.1814"* @_ZNK6lucene6search13WildcardQuery5cloneEv(%"class.lucene::search::WildcardQuery.2404"* nocapture %this) align 2 {
entry:
  %call = tail call noalias i8* @_Znwj(i32 12)
  %0 = bitcast i8* %call to %"class.lucene::search::MultiTermQuery.1815"*
  %1 = getelementptr inbounds %"class.lucene::search::WildcardQuery.2404"* %this, i32 0, i32 0
  invoke void @_ZN6lucene6search14MultiTermQueryC2ERKS1_(%"class.lucene::search::MultiTermQuery.1815"* %0, %"class.lucene::search::MultiTermQuery.1815"* %1)
          to label %invoke.cont unwind label %lpad

invoke.cont:                                      ; preds = %entry
  %2 = bitcast i8* %call to i32 (...)***
  store i32 (...)** bitcast (i8** getelementptr inbounds ([13 x i8*]* @_ZTVN6lucene6search13WildcardQueryE, i32 0, i32 2) to i32 (...)**), i32 (...)*** %2, align 4
  %3 = bitcast i8* %call to %"class.lucene::search::Query.1814"*
  ret %"class.lucene::search::Query.1814"* %3

lpad:                                             ; preds = %entry
  %4 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
          cleanup
  tail call void @_ZdlPv(i8* %call) nounwind
  resume { i8*, i32 } %4
}



Yours sincerely,
Kadysev Mikhail