bbc40e7822
Currently, when rustc compiles code with `-Clto` enabled that was built with different choices for `-Zdwarf-version`, a warning will be reported. It's very easy to observe this by compiling most anything (eg, "hello world") and specifying `-Clto -Zdwarf-version=5` since the standard library is distributed with `-Zdwarf-version=4`. This behavior isn't actually useful for a few reasons: - from observation, LLVM chooses to pick the highest DWARF version anyway after issuing the warning - Clang specifies that in this case, the max version should be picked without a warning and as a general principle, we want to support x-lang LTO with Clang which implies using the same module flag merge behaviors - Debuggers need to be able to handle a variety of versions withing the same debugging session as you can easily have some parts of a binary (or some dynamic libraries within an application) all compiled with different DWARF versions This commit changes the module flag merge behavior to match Clang and use the highest version of DWARF. It also adds a test to ensure this behavior is respected in the case of two crates being LTO'd together and updates the test added in the previous commit to ensure no warning is printed.
This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.
Why Rust?
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Performance: Fast and memory-efficient, suitable for critical services, embedded devices, and easily integrated with other languages.
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Reliability: Our rich type system and ownership model ensure memory and thread safety, reducing bugs at compile-time.
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