Avoid build errors with -O0 due to assembly

parent 3551901c
......@@ -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
......
......@@ -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__)
......
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