From 25caaf36a618f687d45c1f724049717a15521082 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Manuel=20P=C3=A9gouri=C3=A9-Gonnard?= Date: Fri, 8 Jan 2016 14:29:11 +0100 Subject: [PATCH] Avoid build errors with -O0 due to assembly --- ChangeLog | 5 +++++ include/mbedtls/bn_mul.h | 18 +++++++++++++++++- 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index ef62ddb0a..f68333e7a 100644 --- a/ChangeLog +++ b/ChangeLog @@ -8,6 +8,11 @@ Bugfix Follath. #309 * Fix issue in Makefile that prevented building using armar. #386 +Changes + * On ARM platforms, when compiling with -O0 with GCC, Clang or armcc5, + don't use the optimized assembly for bignum multiplication. This removes + the need to pass -fomit-frame-pointer to avoid a build error with -O0. + = mbed TLS 2.2.1 released 2016-01-05 Security diff --git a/include/mbedtls/bn_mul.h b/include/mbedtls/bn_mul.h index 5408d4146..c59cbc77a 100644 --- a/include/mbedtls/bn_mul.h +++ b/include/mbedtls/bn_mul.h @@ -563,7 +563,23 @@ #endif /* TriCore */ -#if defined(__arm__) +/* + * gcc -O0 by default uses r7 for the frame pointer, so it complains about our + * use of r7 below, unless -fomit-frame-pointer is passed. Unfortunately, + * passing that option is not easy when building with yotta. + * + * On the other hand, -fomit-frame-pointer is implied by any -Ox options with + * x !=0, which we can detect using __OPTIMIZE__ (which is also defined by + * clang and armcc5 under the same conditions). + * + * So, only use the optimized assembly below for optimized build, which avoids + * the build error and is pretty reasonable anyway. + */ +#if defined(__GNUC__) && !defined(__OPTIMIZE__) +#define CANNOT_USE_R7 +#endif + +#if defined(__arm__) && !defined(CANNOT_USE_R7) #if defined(__thumb__) && !defined(__thumb2__)