Add FreeBSD support to address sanitizer process mapping facilities

[samsonov]

Please fix revision name and provide a motivation for the change in description.

lib/asan/asan_mapping.h

100

Consider using SANITIZER_FREEBSD here.

[kutuzov.viktor.84]

defined(FreeBSD)## replaced with SANITIZER_FREEBSD.

[kutuzov.viktor.84]

Revision name clarified.

[samsonov]

LGTM

[kutuzov.viktor.84]

Committed as rL208537.

lib/asan/asan_mapping.h

 // || `[0x00000000, 0x1fffffff]` || LowMem     ||
 //
 // Default Linux/MIPS mapping:
 // || `[0x2aaa8000, 0xffffffff]` || HighMem    ||
 // || `[0x0fffd000, 0x2aaa7fff]` || HighShadow ||
 // || `[0x0bffd000, 0x0fffcfff]` || ShadowGap  ||
 // || `[0x0aaa8000, 0x0bffcfff]` || LowShadow  ||
 // || `[0x00000000, 0x0aaa7fff]` || LowMem     ||
+//
+// Shadow mapping on FreeBSD/x86-64 with SHADOW_OFFSET == 0x400000000000:
+// || `[0x500000000000, 0x7fffffffffff]` || HighMem    ||
+// || `[0x4a0000000000, 0x4fffffffffff]` || HighShadow ||
+// || `[0x480000000000, 0x49ffffffffff]` || ShadowGap  ||
+// || `[0x400000000000, 0x47ffffffffff]` || LowShadow  ||
+// || `[0x000000000000, 0x3fffffffffff]` || LowMem     ||
+//
+// Shadow mapping on FreeBSD/i386 with SHADOW_OFFSET == 0x40000000:
+// || `[0x60000000, 0xffffffff]` || HighMem    ||
+// || `[0x4c000000, 0x5fffffff]` || HighShadow ||
+// || `[0x48000000, 0x4bffffff]` || ShadowGap  ||
+// || `[0x40000000, 0x47ffffff]` || LowShadow  ||
+// || `[0x00000000, 0x3fffffff]` || 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 kDefaultShort64bitShadowOffset = 0x7FFF8000;  // < 2G.
 static const u64 kAArch64_ShadowOffset64 = 1ULL << 36;
 static const u64 kMIPS32_ShadowOffset32 = 0x0aaa8000;
+static const u64 kFreeBSD_ShadowOffset32 = 1ULL << 30;  // 0x40000000
+static const u64 kFreeBSD_ShadowOffset64 = 1ULL << 46;  // 0x400000000000
 
 #define SHADOW_SCALE kDefaultShadowScale
 #if SANITIZER_ANDROID
 # define SHADOW_OFFSET (0)
 #else
 # if SANITIZER_WORDSIZE == 32
 #  if defined(__mips__)
 #    define SHADOW_OFFSET kMIPS32_ShadowOffset32
+#  elif SANITIZER_FREEBSD
+#    define SHADOW_OFFSET kFreeBSD_ShadowOffset32
 #  else
 #    if SANITIZER_IOS
 #      define SHADOW_OFFSET kIosShadowOffset32
 #    else
 #      define SHADOW_OFFSET kDefaultShadowOffset32
 #    endif
 #  endif
 # else
 #  if defined(__aarch64__)
 #    define SHADOW_OFFSET kAArch64_ShadowOffset64
+#  elif SANITIZER_FREEBSD
+#    define SHADOW_OFFSET kFreeBSD_ShadowOffset64
 #  elif SANITIZER_MAC
 #   define SHADOW_OFFSET kDefaultShadowOffset64
 #  else
 #   define SHADOW_OFFSET kDefaultShort64bitShadowOffset
 #  endif
 # endif
 #endif