Variable tvm::attr::kSystemLibPrefix

• Defined in File module.h

Variable Documentation

constexpr ffi::reflection::AttrKey<ffi::String> tvm::attr::kSystemLibPrefix = {"system_lib_prefix"}

A prefix for generating C symbols system lib creation.

This prefix guides passes that creates global_symbol for internal functions that may have c linkage (e.g. TIR functions and some BYOC functions). It also affects the symbol of the fat bin blob during module export.

This attribute is used to avoid symbol conflict when we generate and combine multiple system libs that get linked into one.

Rationale: mechanisms like BYOC rely on the common global symbol and each external compiler also has its own mechanism of mangling. As a result, we cannot rely on other mechanisms on setting a global_symbol and then renaming, because the external compiler already agreed on the name.

system_lib_prefix provides a way to hint at the passes to allow names to avoid name conflict at the beginning.

Note that users can still directly specify global symbols that may conflict. It is up to the downstream toolchain to manage those external-facing functions.

This does not affect non-C linkage functions it is less of an issue because they will be embedded into fatbin that in different symbols, The system lib loader can pick the right prefix for a given prefix.

Having this attribute implies system lib generation linkage.