tree 6a1f63107ca7e834eae75c613cf860cf5416c540
parent 45608a1b9feb53ad8378891680134cebd4021c52
author David Benjamin <davidben@google.com> 1634672525 -0400
committer Adam Langley <agl@google.com> 1634751354 +0000

Use C preprocessor comments in assembly headers.

We generate .S files for assembly, which means they run through the C
preprocessor first. In gas targets where # is the comment marker, there
is a conflict with cpp directives.

The comments actually rely on #This and #source not being directives. If
I begin a line with "if", the build fails. Since the C preprocessor is
responsible for removing C preprocessor comments, we should be able to
safely use // everywhere with less ambiguity.

(In fact, we were already relying on this for 32-bit ARM. The 32-bit ARM
gas line comment marker is @. 64-bit ARM uses //, and x86/x86_64/ppc64
use #.)

This reportedly causes issues for goma. See
https://bugs.chromium.org/p/boringssl/issues/detail?id=448#c3

Bug: 448
Change-Id: Ib58f3152691c1dbcccfc045f21f486b56824283d
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/49965
Reviewed-by: Adam Langley <agl@google.com>