Simplify __ARM_ARCH__ definition.

OpenSSL's assembly files have a few places where we condition code on
__ARM_ARCH__, the minimum target ARM revision. It currently only
controls some pre-ARMv7 code. This symbol has, from what I can tell, the
same semantics as __ARM_ARCH, defined in Arm C Language Extensions, and
added in GCC 4.8 and Clang 3.2:;a=commitdiff;h=9e94a7fc5ab770928b9e6a2b74e292d35b4c94da;hp=25bab91e017eb1d6d93117f3da96fa9b43703190

Those are over nine years old, so drop all the fallback code. Also fix
arm_arch.h to be includable on non-ARM platforms. Some tools expect all
public headers to be cleanly includable and arm_arch.h being "public"
was getting in the way (see cl/416881417).

Interestingly, arm_arch.h previously only computed __ARM_ARCH__ for
__GNUC__ and Clang doesn't define __GNUC__ on Windows. That means we
actually weren't defining __ARM_ARCH__ for Windows. But none of the
aarch64 assembly has __ARM_ARCH__-gated code, so it works out. If it
ever does, that CL smooths that over. I've gated the
__ARM_(MAX_)_ARCH__ bits on __ASSEMBLER__ to avoid breaking no-asm
Windows/aarch64 builds on MSVC. There aren't any uses in C.

Update-Note: ARM assembly now requires the compiler define __ARM_ARCH.
This is not expected to break Clang or GCC from the last 8 or 9 years.

Change-Id: Id45e95406edeecf8dda11dce9e82418516e9de1f
Reviewed-by: Adam Langley <>
1 file changed
tree: c37dcefa7f2c7cf03da033752a497934764636aa
  1. .github/
  2. crypto/
  3. decrepit/
  4. fuzz/
  5. include/
  6. ssl/
  7. third_party/
  8. tool/
  9. util/
  10. .clang-format
  11. .gitignore
  15. CMakeLists.txt
  24. codereview.settings
  25. go.mod
  26. go.sum
  27. sources.cmake


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: