Always use adr with __thumb2__.
Thumb2 addresses are a bit a mess, depending on whether a label is
interpreted as a function pointer value (for use with BX and BLX) or as
a program counter value (for use with PC-relative addressing). Clang's
integrated assembler mis-assembles this code. See
https://crbug.com/124610#c54 for details.
Instead, use the ADR pseudo-instruction which has clear semantics and
should be supported by every assembler that handles the OpenSSL Thumb2
code. (In other files, the ADR vs SUB conditionals are based on
__thumb2__ already. For some reason, this one is based on __APPLE__, I'm
guessing to deal with an older version of clang assembler.)
It's unclear to me which of clang or binutils is "correct" or if this is
even a well-defined notion beyond "whatever binutils does". But I will
note that https://github.com/openssl/openssl/pull/4669 suggests binutils
has also changed behavior around this before.
See also https://github.com/openssl/openssl/pull/5431 in OpenSSL.
Bug: chromium:124610
Change-Id: I5e7a0c8c0f54a3f65cc324ad599a41883675f368
Reviewed-on: https://boringssl-review.googlesource.com/26164
Commit-Queue: Steven Valdez <svaldez@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/crypto/fipsmodule/aes/asm/bsaes-armv7.pl b/crypto/fipsmodule/aes/asm/bsaes-armv7.pl
index fa1e434..775dbd5 100644
--- a/crypto/fipsmodule/aes/asm/bsaes-armv7.pl
+++ b/crypto/fipsmodule/aes/asm/bsaes-armv7.pl
@@ -742,7 +742,7 @@
_bsaes_decrypt8:
adr $const,.
vldmia $key!, {@XMM[9]} @ round 0 key
-#ifdef __APPLE__
+#if defined(__thumb2__) || defined(__APPLE__)
adr $const,.LM0ISR
#else
add $const,$const,#.LM0ISR-_bsaes_decrypt8
@@ -841,7 +841,7 @@
_bsaes_encrypt8:
adr $const,.
vldmia $key!, {@XMM[9]} @ round 0 key
-#ifdef __APPLE__
+#if defined(__thumb2__) || defined(__APPLE__)
adr $const,.LM0SR
#else
sub $const,$const,#_bsaes_encrypt8-.LM0SR
@@ -949,7 +949,7 @@
_bsaes_key_convert:
adr $const,.
vld1.8 {@XMM[7]}, [$inp]! @ load round 0 key
-#ifdef __APPLE__
+#if defined(__thumb2__) || defined(__APPLE__)
adr $const,.LM0
#else
sub $const,$const,#_bsaes_key_convert-.LM0
