Build multi models into one system-lib

[fantasyRqg]

Deploy models on Android & iOS platform must use system-lib. Avoid usage of dlopen.
bundle_deploy demonstrated how to deploy a model which build a model which target system-lib

BUT we need more than one models

Related Discussions:

• How to deploy two different tvm compiled model in c++ statically?
• Combine multi SYSTEM-LIB module libs to one. The implementation steps are different from what I thought at the beginning

cc @wweic @zhiics

Please forgive me for my poor English

[FrozenGene]

@kazum Could you help to review it? As it is somehow related with iOS.

[ziyu-guo]

Quick question: how does this work with multiple TVM module libs compiled from same model, but with different batch size? Won't the names collide in the combined lib?

[fantasyRqg]

tvm/src/relay/backend/compile_engine.cc

Lines 803 to 836 in 3635945

	/*!
	* \brief Get unique name from name.
	* \param name The orginal name.
	* \return Updated name which is unique.
	*/
	std::string GetUniqueName(std::string name) {
	for (size_t i = 0; i < name.length(); ++i) {
	if (name[i] == '.') name[i] = '_';
	}
	while (true) {
	auto it = name_map_.find(name);
	if (it == name_map_.end()) {
	name_map_[name] = 1;
	return name;
	} else {
	std::ostringstream os;
	os << name << "_" << it->second;
	++(it->second);
	name = os.str();
	}
	}
	return name;
	}
	/*! \brief compiler cache lock*/
	std::mutex mutex_;
	/*! \brief internal name map to get an unique name */
	std::unordered_map<std::string, int> name_map_;
	/*! \brief internal compiler cache */
	std::unordered_map<CCacheKey, CCacheValue> cache_;
	/*! \brief internal compiler cache for shape funcs */
	std::unordered_map<CCacheKey, CCacheValue> shape_func_cache_;
	/*! \brief the cache key of the function that is being lowered currently*/
	CCacheKey cur_ccache_key_;
	};

GetUniqueName make sure function names will not collide

name_map_ will not be cleand even after CompileEngine::Global()->Clear();

@ziyu-guo

[fantasyRqg]

Seems batch size is not handled by relay.build either.
My implementation just follow relay.build

[AlexanderSerov]

Is this planned to be included in v0.8?

[jroesch]

This PR appears to be out of date, please feel free to reopen it if this is not the case.

As part of the new year we are attempting to triage the project's open pull requests to ensure that code which
is ready for review and/or merging receives adequate attention.

Thanks again for your contribution, and feel free to reach out to discuss these changes.