Working on reconciling out-of-tree patches to compiler-rt for building for iOS.

[beanz]

Summary

This is one of many changes needed for compiler-rt to get it building on iOS.

This change ifdefs out headers and functionality that aren't available on iOS, and adds support for iOS and the iOS simulator to as an.

Note: this change does not enable building for iOS, as there are more changes to come.

[beanz]

Looping in Alexander Potapenko because git blame :-).

[beanz]

Adding Kuba and Justin for review.

[samsonov]

lib/asan/asan_mac.cc

27–35

SANITIZER_IOS

73

Looks like this logic is copied from http://reviews.llvm.org/D10510. Consider introducing a function instead.

lib/asan/asan_mapping.h

100–101

Please group iossim constants together,

120

indentation looks inconsistent.

[beanz]

Updating based on feedback from samsonov.

[samsonov]

lib/asan/asan_mac.cc

28

How did this #include for SANITIZER_IOSSIM before this change?

lib/asan/asan_mapping.h

106

keep defaults together as well.

118

I think you should keep the original code layout and add ios/iossim cases to large #if SANITIZER_WORDSIZE == 32 block, and add ios/iossim cases to large else (SANITIZER_WORDSIZE == 64) block.

[beanz]

lib/asan/asan_mac.cc

28

crt_externs.h exists in the iOS Simulator SDK, but not in the device SDK... Don't ask. I have no answers.

[beanz]

Updating based on feedback from samsonov.

[samsonov]

LGTM (provided SANITIZER_IOS and SANITIZER_IOSSIM would be made mutually exclusive).

lib/asan/asan_mac.cc

28

That's fine, but doesn't this mean we should keep #including <crt_externs.h> on iossim?
I'd actually vote for making SANITIZER_IOS and SANITIZER_IOSSIM exclusive. In this case we won't have to care about correct order of #elif clauses in asan_mapping.h

[beanz]

lib/asan/asan_mac.cc

28

Six one way half a dozen the other.

It will work either way. My general preference is to have the Simulator code follow the iOS code paths everywhere except where it is absolutely necessary to deviate, but I could go either way on this.

I don't think you should make SANITIZER_IOS and SANITIZER_IOSSIM exclusive. The general Darwin model is that the iOS simulator is iOS.

I could easily change the check here to #if (!SANITIZER_IOS) || SANITIZER_IOSSIM.

[samsonov]

lib/asan/asan_mac.cc

28

OK, let's follow the Darwin model here and assume that iossim is ios.

lib/asan/asan_mac.cc

 #include "asan_internal.h"
 #include "asan_mapping.h"
 #include "asan_stack.h"
 #include "asan_thread.h"
 #include "sanitizer_common/sanitizer_atomic.h"
 #include "sanitizer_common/sanitizer_libc.h"
 #include "sanitizer_common/sanitizer_mac.h"
 
-#include <crt_externs.h>  // for _NSGetArgv
+#if !SANITIZER_IOS
+#include <crt_externs.h>  // for _NSGetArgv and _NSGetEnviron
+#else
+extern char **environ;
+extern "C" {
+  extern char ***_NSGetArgv(void);
+}
+#endif
+
 #include <dlfcn.h>  // for dladdr()
 #include <mach-o/dyld.h>
 #include <mach-o/loader.h>
 #include <sys/mman.h>
 #include <sys/resource.h>
 #include <sys/sysctl.h>
 #include <sys/ucontext.h>
 #include <fcntl.h>

 static const char kDyldInsertLibraries[] = "DYLD_INSERT_LIBRARIES";
 LowLevelAllocator allocator_for_env;
 
 // Change the value of the env var |name|, leaking the original value.
 // If |name_value| is NULL, the variable is deleted from the environment,
 // otherwise the corresponding "NAME=value" string is replaced with
 // |name_value|.
 void LeakyResetEnv(const char *name, const char *name_value) {
+#if !SANITIZER_IOS
   char ***env_ptr = _NSGetEnviron();
   CHECK(env_ptr);
   char **environ = *env_ptr;
+#endif
   CHECK(environ);
   uptr name_len = internal_strlen(name);
   while (*environ != 0) {
     uptr len = internal_strlen(*environ);
     if (len > name_len) {
       const char *p = *environ;
       if (!internal_memcmp(p, name, name_len) && p[name_len] == '=') {
         // Match.

lib/asan/asan_mapping.h

 //  on WoW64, /LARGEADDRESSAWARE, etc).
 // || `[0x50000000, 0xffffffff]` || HighMem    ||
 // || `[0x3a000000, 0x4fffffff]` || HighShadow ||
 // || `[0x36000000, 0x39ffffff]` || ShadowGap  ||
 // || `[0x30000000, 0x35ffffff]` || LowShadow  ||
 // || `[0x00000000, 0x2fffffff]` || LowMem     ||
 
 static const u64 kDefaultShadowScale = 3;
 static const u64 kDefaultShadowOffset32 = 1ULL << 29;  // 0x20000000
-static const u64 kIosShadowOffset32 = 1ULL << 30;  // 0x40000000
 static const u64 kDefaultShadowOffset64 = 1ULL << 44;
+static const u64 kIosShadowOffset32 = 1ULL << 30;  // 0x40000000
+static const u64 kIosShadowOffset64 = 0x130000000;
+static const u64 kIosSimShadowOffset32 = 1ULL << 30;
+static const u64 kIosSimShadowOffset64 = kDefaultShadowOffset64;
 static const u64 kDefaultShort64bitShadowOffset = 0x7FFF8000;  // < 2G.
 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa0000;
 static const u64 kMIPS64_ShadowOffset64 = 1ULL << 37;
 static const u64 kPPC64_ShadowOffset64 = 1ULL << 41;
 static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30;  // 0x40000000
 static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
 static const u64 kWindowsShadowOffset32 = 3ULL << 28;  // 0x30000000
 
 #define SHADOW_SCALE kDefaultShadowScale
 #if SANITIZER_ANDROID
 # define SHADOW_OFFSET (0)
+#elif SANITIZER_IOS
+# if SANITIZER_WORDSIZE == 32
+#  if SANITIZER_IOSSIM
+#   define SHADOW_OFFSET kIosSimShadowOffset32
+#  else
+#   define SHADOW_OFFSET kIosShadowOffset32
+#  endif
+# else
+#  if SANITIZER_IOSSIM
+#   define SHADOW_OFFSET kIosSimShadowOffset64
+#  else
+#   define SHADOW_OFFSET kIosShadowOffset64
+#  endif
+# endif
 #else
 # if SANITIZER_WORDSIZE == 32
 #  if defined(__mips__)
 #    define SHADOW_OFFSET kMIPS32_ShadowOffset32
 #  elif SANITIZER_FREEBSD
 #    define SHADOW_OFFSET kFreeBSD_ShadowOffset32
-#  elif SANITIZER_IOS
-#    define SHADOW_OFFSET kIosShadowOffset32
 #  elif SANITIZER_WINDOWS
 #    define SHADOW_OFFSET kWindowsShadowOffset32
 #  else
 #    define SHADOW_OFFSET kDefaultShadowOffset32
 #  endif
 # else
 #  if defined(__aarch64__)
 #    define SHADOW_OFFSET kAArch64_ShadowOffset64