Fix lowering and optimization of 64-bit absolute addresses

x86-64 does not support 64-bit immediates as absolute memory addresses.
They have to be stored in a register, which can then be used as [base].

Previously we addressed this at the SubzeroReactor level by emitting a
Bitcast from an Ice::Operand to an Ice::Variable, for which Subzero
already supported 64-bit constants as input.

This change implements X86OperandMem creation from a 64-bit constant
operand by letting legalize() move it into a GPR and using it as the
memory operand's base register.

A Reactor unit test is added to exercise this.

Another issue was that doLoadOpt() assumed all load instructions are
candidates for fusing into a subsequent instruction which takes the
result of the load. This isn't true when for 64-bit constant addresses
an instruction to copy it into a register is inserted.

For now this case is simply skipped. A future optimization could adjust
the iterators properly so the load from [base] can be fused with the
next instruction.

Lastly, it is possible for a 64-bit constant to fit within a 32-bit
immediate, in which case legalize() by default does not perform the copy
into a GPR (note this is to allow moves and calls with 64-bit
immediates, where they are legal), and simply returns the 64-bit
constant. So we must not allow legalization to an immediate in this
case. Note that while we could replace it with a 32-bit constant, it's
rare for absolute addresses to fit in this range, and it would be
non-deterministic which path is taken, so for consistency we don't
perform this optimization.

Bug: b/148272103
Change-Id: I5fcfa971dc93f2307202ee11619e84c65fe46188
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/52768
Tested-by: Nicolas Capens <nicolascapens@google.com>
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
4 files changed
tree: eb4b9074275cb79ca91ed2696f6b16b193a567b2
  1. .clang-format
  2. .dir-locals.el
  3. .gitignore
  4. .gitmodules
  5. .vscode/
  6. AUTHORS.txt
  7. Android.bp
  8. BUILD.gn
  9. CMakeLists.txt
  10. CMakeSettings.json
  11. CONTRIBUTING.txt
  12. CONTRIBUTORS.txt
  13. DIR_METADATA
  14. LICENSE.txt
  15. OWNERS
  16. README.md
  17. build/
  18. build_overrides/
  19. codereview.settings
  20. docs/
  21. extensions/
  22. include/
  23. infra/
  24. src/
  25. tests/
  26. third_party/
  27. tools/
README.md

SwiftShader

License

Introduction

SwiftShader is a high-performance CPU-based implementation of the Vulkan graphics API12. Its goal is to provide hardware independence for advanced 3D graphics.

NOTE: SwiftShader's OpenGL ES frontend is no longer supported, and will eventually be removed. Read more about our recommendation to use ANGLE on top of SwiftShader Vulkan here.

Building

SwiftShader libraries can be built for Windows, Linux, and macOS.
Android and Chrome (OS) build environments are also supported.

  • CMake
    Install CMake for Linux, macOS, or Windows and use either the GUI or run the following terminal commands:

    cd build
    cmake ..
    cmake --build . --parallel
    
    ./vk-unittests
    

    Tip: Set the CMAKE_BUILD_PARALLEL_LEVEL environment variable to control the level of parallelism.

  • Visual Studio
    To build the Vulkan ICD library, use Visual Studio 2019 to open the project folder and wait for it to run CMake. Open the CMake Targets View in the Solution Explorer and select the vk_swiftshader project to build it.

Usage

The SwiftShader libraries act as drop-in replacements for graphics drivers.

On Windows, most applications can be made to use SwiftShader's DLLs by placing them in the same folder as the executable. On Linux, the LD_LIBRARY_PATH environment variable or -rpath linker option can be used to direct applications to search for shared libraries in the indicated directory first.

In general, Vulkan applications look for a shared library named vulkan-1.dll on Windows (vulkan-1.so on Linux). This ‘loader’ library then redirects API calls to the actual Installable Client Driver (ICD). SwiftShader's ICD is named libvk_swiftshader.dll, but it can be renamed to vulkan-1.dll to be loaded directly by the application. Alternatively, you can set the VK_ICD_FILENAMES environment variable to the path to vk_swiftshader_icd.json file that is generated under the build directory (e.g. .\SwiftShader\build\Windows\vk_swiftshader_icd.json). To learn more about how Vulkan loading works, read the official documentation here.

Contributing

See CONTRIBUTING.txt for important contributing requirements.

The canonical repository for SwiftShader is hosted at: https://swiftshader.googlesource.com/SwiftShader

All changes must be reviewed and approved in the Gerrit review tool at: https://swiftshader-review.googlesource.com

Authenticate your account here: https://swiftshader-review.googlesource.com/new-password

All changes require a Change-ID tag in the commit message. A commit hook may be used to add this tag automatically, and can be found at: https://gerrit-review.googlesource.com/tools/hooks/commit-msg. To clone the repository and install the commit hook in one go:

git clone https://swiftshader.googlesource.com/SwiftShader && (cd SwiftShader && curl -Lo `git rev-parse --git-dir`/hooks/commit-msg https://gerrit-review.googlesource.com/tools/hooks/commit-msg ; chmod +x `git rev-parse --git-dir`/hooks/commit-msg)

Changes are uploaded to Gerrit by executing:

git push origin HEAD:refs/for/master

When ready, add a project owner as a reviewer on your change.

Some tests will automatically be run against the change. Notably, presubmit.sh verifies the change has been formatted using clang-format 10.0. Most IDEs come with clang-format support, but may require downgrading to clang-format version 10.0.

Testing

SwiftShader's OpenGL ES implementation can be tested using the dEQP test suite.

See docs/dEQP.md for details.

Third-Party Dependencies

The third_party directory contains projects which originated outside of SwiftShader:

subzero contains a fork of the Subzero project. It originates from Google Chrome‘s (Portable) Native Client project. The fork was made using git-subtree to include all of Subzero’s history.

llvm-subzero contains a minimized set of LLVM dependencies of the Subzero project.

PowerVR_SDK contains a subset of the PowerVR Graphics Native SDK for running several sample applications.

googletest contains the Google Test project, as a Git submodule. It is used for running unit tests for Chromium, and Reactor unit tests. Run git submodule update --init to obtain/update the code. Any contributions should be made upstream.

Documentation

See docs/Index.md.

Contact

Public mailing list: swiftshader@googlegroups.com

General bug tracker: https://g.co/swiftshaderbugs
Chrome specific bugs: https://bugs.chromium.org/p/swiftshader

License

The SwiftShader project is licensed under the Apache License Version 2.0. You can find a copy of it in LICENSE.txt.

Files in the third_party folder are subject to their respective license.

Authors and Contributors

The legal authors for copyright purposes are listed in AUTHORS.txt.

CONTRIBUTORS.txt contains a list of names of individuals who have contributed to SwiftShader. If you‘re not on the list, but you’ve signed the Google CLA and have contributed more than a formatting change, feel free to request to be added.

Disclaimer

  1. Trademarks are the property of their respective owners.
  2. This is not an official Google product.