Fix vpaes-armv7.pl in ARM mode.

This file runs against the limit of ARMv7's ADR pseudo-instruction. ADR
expands to an ADD or SUB of the pc register to find an address. That
immediate must fit in ARM's encoding scheme: 8 bits of constant and 4
bits of rotation. This means larger values must be more aligned.

ARM additionally has two encodings, ARM and Thumb mode. Our assembly
files may use either encoding (do we actually need to support this?). In
ARM mode, the distances get large enough to require 16-byte alignment.
Moving constants closer to their use resolves most of this, but common
constants in _vpaes_consts are used by the whole file. Affected ADR
instructions must be placed at 8 mod 16 (the pc register is 8 ahead).
Instructions with this constraint have been commented.

For details on ARM's immediate value encoding scheme, see
https://alisdair.mcdiarmid.org/arm-immediate-value-encoding/

Update-Note: See b/141080375
Change-Id: Iadac36d800bb45901b513055fcc28a3a60f9060c
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/37524
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
1 file changed
tree: 2d546c892f384a6ae2dc24a92ede55ab8142177c
  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: