[lldb] Remove timer from SBModule copy ctor

[kastiglione]

Summary

The SBModule copy constructor has fast execution, and is high firing. Fast and
frequent functions are not good candidates for timers.

[JDevlieghere]

There's two issues with this patch:

• LLDB_INSTRUMENT_VA is not the same as LLDB_SCOPED_TIMER. It's used for logging and tracks ABI boundaries. This breaks boundary tracking.
• Next time someone runs lldb-instr on this file, the tool will just add this again.

If we want to avoid the overhead from the timer, we'll need to adjust the macro.

[aprantl]

What about adding a trivial parameter to the macro that has the effect of skipping it in instrumentation if the instrumentation is the costly signpost mechanism?

[kastiglione]

In D142150#4074015, @aprantl wrote:

What about adding a trivial parameter to the macro that has the effect of skipping it in instrumentation if the instrumentation is the costly signpost mechanism?

sounds good to me

[JDevlieghere]

In D142150#4074015, @aprantl wrote:

What about adding a trivial parameter to the macro that has the effect of skipping it in instrumentation if the instrumentation is the costly signpost mechanism?

The _VA macro is variadic so you'd have to define a new macro, but yeah that's the idea. As discussed offline with Dave, we probably never want timers/signposts for constructors. My suggestion is to re-instrument all constructors with that new "trivial" macro. During the reproducer era constructs required different macros, so there should be code in lldb-instr that can already tell the two apart.

lldb/source/API/SBModule.cpp

SBModule::SBModule(const SBModuleSpec &module_spec) {
 
   ModuleSP module_sp;
   Status error = ModuleList::GetSharedModule(
       *module_spec.m_opaque_up, module_sp, nullptr, nullptr, nullptr);
   if (module_sp)
     SetSP(module_sp);
 }
 
-SBModule::SBModule(const SBModule &rhs) : m_opaque_sp(rhs.m_opaque_sp) {
-  LLDB_INSTRUMENT_VA(this, rhs);
-}
+SBModule::SBModule(const SBModule &rhs) = default;
 
 SBModule::SBModule(lldb::SBProcess &process, lldb::addr_t header_addr) {
   LLDB_INSTRUMENT_VA(this, process, header_addr);
 
   ProcessSP process_sp(process.GetSP());
   if (process_sp) {
     m_opaque_sp = process_sp->ReadModuleFromMemory(FileSpec(), header_addr);
     if (m_opaque_sp) {