c++ - How to link two LLVM bitcode modules? -

i have simple llvm pass renames every function defined within current translation unit (i.e: source file in question, after preprocessing steps have taken place - see here). pass follows:

#include <vector> #include <iostream> #include <fstream> #include <string> #include <sstream>  #include "llvm/pass.h" #include "llvm/ir/function.h" #include "llvm/support/raw_ostream.h" #include "llvm/adt/stlextras.h" #include "llvm/adt/smallstring.h" #include "llvm/ir/derivedtypes.h" #include "llvm/ir/module.h" #include "llvm/ir/type.h" #include "llvm/ir/typefinder.h" #include "llvm/transforms/ipo.h" #include "llvm/ir/argument.h" #include "llvm/ir/globalvalue.h"  using namespace llvm;  namespace {    struct functionrename : public modulepass {     static char id; // pass identification     functionrename() : modulepass(id) {}      bool runonmodule(module &m) override {       // rename functions       (auto &f : m) {         stringref name = f.getname();         // leave library functions alone because presence or absence         // affect behaviour of other passes.         if (f.isdeclaration())           continue;         f.setlinkage(globalvalue::linkonceanylinkage);         f.setname(name + "_renamed");       }       return true;     }   }; }  char functionrename::id = 0; static registerpass<functionrename> x("functionrename", "function rename pass"); // ===-------------------------------------------------------==// // // function renamer - renames functions // 

after running pass on bitcode file, file.bc, output result new file file_renamed.bc, follows

opt -load /path/to/libfunctionrenamepass.so -functionrename < file.bc > file_renamed.bc

i attempt link 2 files follows

llvm-link file.bc file_renamed.bc -o file_linked.bc

however, still symbol clashes c++ source files (from initial bitcode file generated) constructors , destructors involved. expectation line

f.setlinkage(globalvalue::linkonceanylinkage)

would prevent symbol clashes occurring symbols defined in file.bc , file_renamed.bc.

what doing wrong?

when tried running code on sample bitcode file, llvm-link step failed due global variables:

error: linking globals named 'my_global': symbol multiply defined! 

after adding second loop runonmodule routine process global variables, llvm-link succeeds , code linked.

for (auto git = m.global_begin(), = m.global_end(); git != get; ++git) {    globalvalue* gv = &*git;    gv->setlinkage(globalvalue::linkonceanylinkage); } 

however, simple test of c++ code constructors worked both , without change.