c++ - LLVM: Clang does not run Pass if CallGraphWrapperPass is a requirement -

i wrote following pass llvm.

using namespace llvm;  namespace {     struct skeletonpass : public functionpass {         static char id;         skeletonpass() : functionpass(id) {}          void getanalysisusage(analysisusage &au) const {             au.addrequired<callgraphwrapperpass>();             au.setpreservesall();         }          virtual bool runonfunction(function &f) {             errs() << "function: " << f.getname() << "!\n";              callgraph &cg = getanalysis<callgraphwrapperpass>().getcallgraph();              return false;         }     }; }   char skeletonpass::id = 0; static registerpass<skeletonpass> x("skeleton", "text"); 

if execute code

opt -load ./libskeletonpass.so -skeleton test.bc > /dev/null  

i correct output. (test.bc can neglected)

according great blog, next command

clang -xclang -load -xclang ./libskeletonpass.so test.c 

should work, long replace last line with:

static void registerskeletonpass(const passmanagerbuilder &,                          legacy::passmanagerbase &pm) {   pm.add(new skeletonpass()); } static registerstandardpasses   registermypass(passmanagerbuilder::ep_earlyaspossible,                  registerskeletonpass); 

the problem clang crashes , returns error:

... clang-3.8: error: unable execute command: segmentation fault (core dumped) clang-3.8: error: clang frontend command failed due signal (use -v see invocation) ... 

without callgraphwrapperpass references clang executes pass correct.

i'm new llvm, there missed?

system: linux 4.4.0 (64bit)

clang version: 3.8.1

the solution change ep_earlyaspossible ep_enabledonoptlevel0.