Debugging of optimized code: Extending the lifetime of local variables

When developing programs, local variables and function parameters are often optimized away by the backend of the compiler to gain the best runtime performance. As a result, these variables and parameters may not be visible when a developer is attempting to debug their optimized programs. For the PS4, game developers commonly write their code with optimizations enabled so they can maintain graphical frame rates (30-60 fps). As such, they regularly encounter loss of debug information, which impacts their productivity. We have introduced an option that forces the various optimization passes to keep local variables and parameters around. This LLVM talk addresses the implementation, effectiveness and performance impact of this feature in front of the LLVM compiler community.