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Understanding the performance of code using LLVM's (llvm-mca)

ARTICLE BY: Andrea Di Biagio
POSTED: Dec 13, 2018
TAGS: Toolchain, Compiler, LLVM

LLVM-mca is a LLVM based tool that uses information available in LLVM’s scheduling models to statically measure the performance of machine code in a specific CPU. The goal of this tool is not just to predict the performance of the code when run on the target, but also to help with diagnosing potential performance issues. In this talk we, will discuss how llvm-mca works and walk the audience through example uses of this tool.

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Debugging of optimized code: Extending the lifetime of local variables

ARTICLE BY: Wolfgang Pieb
POSTED: Nov 30, 2017
TAGS: LLVM, Compiler, Debugger, Toolchain

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.

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Verifying Game Developer Assumptions

ARTICLE BY: Russell Gallop
POSTED: Apr 22, 2015
TAGS: Assembly, Debug, Compiler, Toolchain

Game developers make a number of assumptions about how the compiler works. SN Systems has implemented “Check CFC” (Compile Flow Consistency) to help ensure their assumptions hold true for the PlayStation®4 (PS4) compiler. This has been contributed to the open source LLVM compiler community. Using…

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ABI bugs are a NIGHTMARE!

ARTICLE BY: Sunil Srivastava
POSTED: Dec 18, 2014
TAGS: ABI, Compiler, Toolchain

Release-to-release compatibility is critical in the games industry, where old games must be able to run on an updated PlayStation® operating system. To guard against incompatibilities from creeping in, we developed a C++ ABI test suite for all currently supported PlayStation® platforms (PlayStation®3 (PS3) and PlayStation®Vita (PS Vita) as well as PlayStation®4 (PS4)).

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