Automatically disable assembly with MSAN.

MSAN is incompatible with hand-written assembly code. Previously we
required that OPENSSL_NO_ASM be set when building with MSAN, and the
CMake build would take care of this. However, with other build systems
it wasn't always so easy.

This change automatically disables assembly when the compiler is
configured for MSAN.

Change-Id: I6c219120f62d16b99bafc2efb02948ecbecaf87f
Reviewed-on: https://boringssl-review.googlesource.com/31724
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

CMakeLists.txt

@@ -274,7 +274,7 @@ if(MSAN)
 
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=memory -fsanitize-memory-track-origins -fno-omit-frame-pointer")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=memory -fsanitize-memory-track-origins -fno-omit-frame-pointer")
-  set(OPENSSL_NO_ASM "1")
+  set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -fsanitize=memory -fsanitize-memory-track-origins -fno-omit-frame-pointer")
 endif()
 
 if(ASAN)
@@ -284,7 +284,6 @@ if(ASAN)
 
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=address -fsanitize-address-use-after-scope -fno-omit-frame-pointer")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=address -fsanitize-address-use-after-scope -fno-omit-frame-pointer")
-  set(OPENSSL_NO_ASM "1")
 endif()
 
 if(CFI)

crypto/crypto.c

@@ -19,19 +19,6 @@
 #include "internal.h"
 
 
-#if defined(OPENSSL_MSAN) && !defined(OPENSSL_NO_ASM)
-// MSan works by instrumenting memory accesses in the compiler. Accesses from
-// uninstrumented code, such as assembly, are invisible to it. MSan will
-// incorrectly report reads from assembly-initialized memory as uninitialized.
-// If building BoringSSL with MSan, exclude assembly files from the build and
-// define OPENSSL_NO_ASM.
-//
-// This is checked here rather than in a header because the consumer might not
-// define OPENSSL_NO_ASM. It is only necessary for BoringSSL source files to be
-// built with it.
-#error "BoringSSL must be built with assembly disabled to use MSan."
-#endif
-
 #if !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_STATIC_ARMCAP) && \
     (defined(OPENSSL_X86) || defined(OPENSSL_X86_64) || \
      defined(OPENSSL_ARM) || defined(OPENSSL_AARCH64) || \

crypto/curve25519/asm/x25519-asm-arm.S

@@ -17,6 +17,12 @@
  * domain licensed but the standard ISC license is included above to keep
  * licensing simple. */
 
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer) && !defined(OPENSSL_NO_ASM)
+#define OPENSSL_NO_ASM
+#endif
+#endif
+
 #if !defined(OPENSSL_NO_ASM) && defined(__arm__) && !defined(__APPLE__)
 
 #if defined(BORINGSSL_PREFIX)

crypto/perlasm/arm-xlate.pl

@@ -130,6 +130,16 @@ sub expand_line {
     return $line;
 }
 
+print <<___;
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer) && !defined(OPENSSL_NO_ASM)
+#define OPENSSL_NO_ASM
+#endif
+#endif
+
+#if !defined(OPENSSL_NO_ASM)
+___
+
 print "#if defined(__arm__)\n" if ($flavour eq "linux32");
 print "#if defined(__aarch64__)\n" if ($flavour eq "linux64");
 
@@ -184,5 +194,6 @@ while(my $line=<>) {
 }
 
 print "#endif\n" if ($flavour eq "linux32" || $flavour eq "linux64");
+print "#endif  // !OPENSSL_NO_ASM";
 
 close STDOUT;

crypto/perlasm/ppc-xlate.pl

@@ -255,6 +255,16 @@ my $darn = sub {
     "	.long	".sprintf "0x%X",(31<<26)|($rt<<21)|($l<<16)|(755<<1);
 };
 
+print <<___;
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer) && !defined(OPENSSL_NO_ASM)"
+#define OPENSSL_NO_ASM"
+#endif
+#endif
+
+#if !defined(OPENSSL_NO_ASM) && defined(__powerpc64__)
+___
+
 while($line=<>) {
 
     $line =~ s|[#!;].*$||;	# get rid of asm-style comments...
@@ -296,4 +306,6 @@ while($line=<>) {
     print "\n";
 }
 
+print "#endif  // !OPENSSL_NO_ASM && __powerpc64__";
+
 close STDOUT;

crypto/perlasm/x86_64-xlate.pl

@@ -1139,10 +1139,21 @@ ___
 OPTION	DOTNAME
 ___
 }
-print STDOUT "#if defined(__x86_64__) && !defined(OPENSSL_NO_ASM)\n" if ($gas);
+
-print STDOUT "#if defined(BORINGSSL_PREFIX)\n" if ($gas);
+if ($gas) {
-print STDOUT "#include <boringssl_prefix_symbols_asm.h>\n" if ($gas);
+	print <<___;
-print STDOUT "#endif\n" if ($gas);
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer) && !defined(OPENSSL_NO_ASM)
+#define OPENSSL_NO_ASM
+#endif
+#endif
+
+#if defined(__x86_64__) && !defined(OPENSSL_NO_ASM)
+#if defined(BORINGSSL_PREFIX)
+#include <boringssl_prefix_symbols_asm.h>
+#endif
+___
+}
 
 while(defined(my $line=<>)) {
 

crypto/poly1305/poly1305_arm_asm.S

@@ -1,3 +1,9 @@
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer) && !defined(OPENSSL_NO_ASM)
+#define OPENSSL_NO_ASM
+#endif
+#endif
+
 #if defined(__arm__) && !defined(OPENSSL_NO_ASM) && !defined(__APPLE__)
 
 #if defined(BORINGSSL_PREFIX)

include/openssl/base.h

@@ -231,9 +231,17 @@ extern "C" {
 #endif
 #if __has_feature(memory_sanitizer)
 #define OPENSSL_MSAN
+#define OPENSSL_ASM_INCOMPATIBLE
 #endif
 #endif
 
+#if defined(OPENSSL_ASM_INCOMPATIBLE)
+#undef OPENSSL_ASM_INCOMPATIBLE
+#if !defined(OPENSSL_NO_ASM)
+#define OPENSSL_NO_ASM
+#endif
+#endif  // OPENSSL_ASM_INCOMPATIBLE
+
 // CRYPTO_THREADID is a dummy value.
 typedef int CRYPTO_THREADID;