disable llvm optimizations in JIT when generating output

When saving native code we re-run optimization on the whole module
as part of object file emission, so it is not needed for JIT compiled
code. We are already passing -O0 for package precompilation; this
extends that benefit to the system image.

src/jitlayers.cpp

@@ -439,7 +439,13 @@ JuliaOJIT::JuliaOJIT(TargetMachine &TM)
  }
  )
 {
- addOptimizationPasses(&PM);
+ if (!jl_generating_output()) {
+ addOptimizationPasses(&PM);
+ }
+ else {
+ PM.add(createLowerGCFramePass(tbaa_gcframe));
+ PM.add(createLowerPTLSPass(imaging_mode, tbaa_const));
+ }
  if (TM.addPassesToEmitMC(PM, Ctx, ObjStream))
  llvm_unreachable("Target does not support MC emission.");
 
@@ -1038,6 +1044,7 @@ static void jl_gen_llvm_globaldata(llvm::Module *mod, ValueToValueMapTy &VMap,
 extern "C"
 void jl_dump_native(const char *bc_fname, const char *obj_fname, const char *sysimg_data, size_t sysimg_len)
 {
+ JL_TIMING(NATIVE_DUMP);
  assert(imaging_mode);
  // We don't want to use MCJIT's target machine because
  // it uses the large code model and we may potentially

src/timing.h

@@ -46,7 +46,8 @@ static inline uint64_t rdtscp(void)
  X(AST_COMPRESS), \
  X(AST_UNCOMPRESS), \
  X(SYSIMG_LOAD), \
- X(SYSIMG_DUMP),
+ X(SYSIMG_DUMP), \
+ X(NATIVE_DUMP),
 
 enum jl_timing_owners {
 #define X(name) JL_TIMING_ ## name