Topic: ARMCC byte alignment cannot be greater than 8 bytes warning
1. wolfSSL source code
/* Only use alignment in wolfSSL/wolfCrypt if WOLFSSL_USE_ALIGN is set */
#ifdef WOLFSSL_USE_ALIGN
/* For IAR ARM the maximum variable alignment on stack is 8-bytes.
* Variables declared outside stack (like static globals) can have
* higher alignment. */
#if defined(__ICCARM__)
#define WOLFSSL_ALIGN(x) XALIGNED(8)
#else
#define WOLFSSL_ALIGN(x) XALIGNED(x)
#endif
#else
#define WOLFSSL_ALIGN(x) /* null expansion */
#endif
#ifndef ALIGN8
#define ALIGN8 WOLFSSL_ALIGN(8)
#endif
#ifndef ALIGN16
#define ALIGN16 WOLFSSL_ALIGN(16)
#endif
#ifndef ALIGN32
#define ALIGN32 WOLFSSL_ALIGN(32)
#endif
#ifndef ALIGN64
#define ALIGN64 WOLFSSL_ALIGN(64)
#endif
#ifndef ALIGN128
#define ALIGN128 WOLFSSL_ALIGN(128)
#endif
#ifndef ALIGN256
#define ALIGN256 WOLFSSL_ALIGN(256)
#endif
#if !defined(PEDANTIC_EXTENSION)
#if defined(__GNUC__)
#define PEDANTIC_EXTENSION __extension__
#else
#define PEDANTIC_EXTENSION
#endif
#endif /* !PEDANTIC_EXTENSION */2. ARMCC warning info
wolfcrypt\src\kdf.c(87): warning: #1041-D: alignment for an auto object may not be larger than 8
3. How should I solve this warning? I can think of two ways:
a. Add recognition of ARMCC macro definition, and when it is recognized as an ARMCC compiler, perform the same behavior as the IAR ARM compiler, that is, 8-byte alignment.
b. Write a custom #define ALIGN8 macro for each byte alignment function
What should I do to deal with it reasonably and without any problems?