Add assembly support for -fsanitize=hwaddress tagged globals.

As of LLVM r368102, Clang will set a pointer tag in bits 56-63 of the
address of a global when compiling with -fsanitize=hwaddress. This requires
an adjustment to assembly code that takes the address of such globals: the
code cannot use the regular R_AARCH64_ADR_PREL_PG_HI21 relocation to refer
to the global, since the tag would take the address out of range. Instead,
the code must use the non-checking (_NC) variant of the relocation (the
link-time check is substituted by a runtime check).

This change makes the necessary adjustment in all of the places where it
is needed when compiling with -fsanitize=hwaddress. While here, shrink the
code by an instruction in each of those places by folding the addend into
the load, and remove some dead code that seems to have been left over from
commit 293d9ee4e837d122a28cd992e37779a5de48dc7f.

We check for a sufficiently new clang before using the :pg_hi21_nc: relocation
variant because support for this variant was only added recently.

Change-Id: Ic9da8386e19c03c1e90c103a81232a254277e9a5
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/36924
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
4 files changed
tree: 28c2e417c2c35657511fa720b5c30bce36b17d11
  1. .clang-format
  2. .github/
  3. .gitignore
  4. API-CONVENTIONS.md
  5. BREAKING-CHANGES.md
  6. BUILDING.md
  7. CMakeLists.txt
  8. CONTRIBUTING.md
  9. FUZZING.md
  10. INCORPORATING.md
  11. LICENSE
  12. PORTING.md
  13. README.md
  14. STYLE.md
  15. codereview.settings
  16. crypto/
  17. decrepit/
  18. fuzz/
  19. go.mod
  20. include/
  21. sources.cmake
  22. ssl/
  23. third_party/
  24. tool/
  25. util/
README.md

BoringSSL

BoringSSL is a fork of OpenSSL that is designed to meet Google's needs.

Although BoringSSL is an open source project, it is not intended for general use, as OpenSSL is. We don't recommend that third parties depend upon it. Doing so is likely to be frustrating because there are no guarantees of API or ABI stability.

Programs ship their own copies of BoringSSL when they use it and we update everything as needed when deciding to make API changes. This allows us to mostly avoid compromises in the name of compatibility. It works for us, but it may not work for you.

BoringSSL arose because Google used OpenSSL for many years in various ways and, over time, built up a large number of patches that were maintained while tracking upstream OpenSSL. As Google's product portfolio became more complex, more copies of OpenSSL sprung up and the effort involved in maintaining all these patches in multiple places was growing steadily.

Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it's not part of the NDK) and a number of other apps/programs.

Project links:

There are other files in this directory which might be helpful: