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llvm / llvm-project / 744d469500d209b7bf548d81f607d61a156db2e6
commit744d469500d209b7bf548d81f607d61a156db2e6[log] [tgz]
authorThurston Dang <thurston@google.com>Wed Apr 24 10:38:12 2024 -0700
committerGitHub <noreply@github.com>Wed Apr 24 10:38:12 2024 -0700
treeb7831ca7b06659965293cd9bdaf053c2a4e3d976
parentfd9273593390c4e5004bba27eeeea60e44175dcf [diff]
[hwasan] Optimize outlined memaccess for fixed shadow on Aarch64 (#88544)

The HWASan transform currently always uses x20 to pass the shadow base to hwasan_check_memaccess_shortgranules, even if the shadow base is a constant known at compile time (e.g., for Fuchsia, KHWASan, or via -hwasan-mapping-offset).  This patch uses the fixed shadow variant of the hwasan_check_memaccess_shortgranules intrinsic (introduced in https://github.com/llvm/llvm-project/commit/365bddf634993d5ea357e9715d8aacd7ee40c4b5), allowing the shadow base to be materialized inside the memaccess callee.

We currently only support this optimization for AArch64; it is a no-op on other platforms due to lack of support for lowering the intrinsic.

Note: when a binary is instrumented with -hwasan-mapping-offset, it is necessary to specify HWASAN_OPTIONS=fixed_shadow_base=... (see ea991a11b2a3d2bfa545adbefb71cd17e8970a43) at runtime to ensure the shadow is mapped appropriately.
4 files changed
tree: b7831ca7b06659965293cd9bdaf053c2a4e3d976
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. libc/
  11. libclc/
  12. libcxx/
  13. libcxxabi/
  14. libunwind/
  15. lld/
  16. lldb/
  17. llvm/
  18. llvm-libgcc/
  19. mlir/
  20. offload/
  21. openmp/
  22. polly/
  23. pstl/
  24. runtimes/
  25. third-party/
  26. utils/
  27. .clang-format
  28. .clang-tidy
  29. .git-blame-ignore-revs
  30. .gitattributes
  31. .gitignore
  32. .mailmap
  33. CODE_OF_CONDUCT.md
  34. CONTRIBUTING.md
  35. LICENSE.TXT
  36. pyproject.toml
  37. README.md
  38. SECURITY.md
README.md

The LLVM Compiler Infrastructure

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Welcome to the LLVM project!

This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.

The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.

C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.

Other components include: the libc++ C++ standard library, the LLD linker, and more.

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