From 1a9bc441270732fd89e2a2d268c122ade759d7f9 Mon Sep 17 00:00:00 2001 From: Brian Smith Date: Mon, 16 Mar 2015 19:27:05 -1000 Subject: [PATCH] Fix standalone Windows release-mode builds. `cmake -GNinja .. -DCMAKE_BUILD_TYPE=Release` fails without this patch, when building using MSVC 2013. MSVC will detect (in release builds only, it seems) that functions that call abort will never return, and then warn that any code after a call to one of them is unreachable. Since we treat warnings as errors when building, this breaks the build. While this is usually desirable, it isn't desirable in this case. Change-Id: Ie5f24b1beb60fd2b33582a2ceef4c378ad0678fb Reviewed-on: https://boringssl-review.googlesource.com/3960 Reviewed-by: Adam Langley --- crypto/cipher/e_aes.c | 6 ++++-- crypto/internal.h | 20 ++++++++++++++++++++ 2 files changed, 24 insertions(+), 2 deletions(-) diff --git a/crypto/cipher/e_aes.c b/crypto/cipher/e_aes.c index 6e4b7a08..99883450 100644 --- a/crypto/cipher/e_aes.c +++ b/crypto/cipher/e_aes.c @@ -283,7 +283,8 @@ void aesni_ctr32_encrypt_blocks(const uint8_t *in, uint8_t *out, size_t blocks, #endif static int aes_init_key(EVP_CIPHER_CTX *ctx, const uint8_t *key, - const uint8_t *iv, int enc) { + const uint8_t *iv, int enc) + OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS { int ret, mode; EVP_AES_KEY *dat = (EVP_AES_KEY *)ctx->cipher_data; @@ -404,7 +405,8 @@ static char aesni_capable(void); static ctr128_f aes_ctr_set_key(AES_KEY *aes_key, GCM128_CONTEXT *gcm_ctx, block128_f *out_block, const uint8_t *key, - size_t key_len) { + size_t key_len) + OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS { if (aesni_capable()) { aesni_set_encrypt_key(key, key_len * 8, aes_key); if (gcm_ctx != NULL) { diff --git a/crypto/internal.h b/crypto/internal.h index 30e6e924..38f9820e 100644 --- a/crypto/internal.h +++ b/crypto/internal.h @@ -120,6 +120,26 @@ extern "C" { #endif +/* MSVC will sometimes correctly detect unreachable code and issue a warning, + * which breaks the build since we treat errors as warnings, in some rare cases + * where we want to allow the dead code to continue to exist. In these + * situations, annotate the function containing the unreachable code with + * OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS after its parameters: + * + * void f() OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS { + * ... + * } + * + * Note that MSVC's reachability analysis seems to operate on a whole-function + * basis, so the annotation must be placed on the entire function, not just a + * block within the function. */ +#if defined(_MSC_VER) +#define OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS \ + __pragma(warning(suppress:4702)) +#else +#define OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS +#endif + /* st_CRYPTO_EX_DATA_IMPL contains an ex_data implementation. See the comments * in ex_data.h for details of the behaviour of each of the functions. */ struct st_CRYPTO_EX_DATA_IMPL {