tsan: remove indirection when selecting the active mapping

[dvyukov]

Summary

Currently there are 2 levels when selecting the active mapping:
the branchy ifdef tree + another ifdef tree in SelectMapping.
Moreover, there is an additional indirection for some platforms
via HAS_48_BIT_ADDRESS_SPACE define. This makes already complex
logic even more complex and almost impossible to read.
Remove one level of indirection and define the active mapping
in SelectMapping.

Depends on D107742.

[dvyukov]

changed SelectMapping to use template Arg and rebased

[DavidSpickett]

This has caused test failures on our AArch64 bots:
https://lab.llvm.org/buildbot/#/builders/179/builds/603

All along the lines of:

FATAL: ThreadSanitizer: unexpected memory mapping 0xfffff6200000-0xfffff6300000

Commenting on this change in particular because it's the most recent one a bisect thought might be the issue:

$ git bisect bad
There are only 'skip'ped commits left to test.
The first bad commit could be any of:
3830c93478d39f66ce3bdacaac600c43d90e8076
fd5060073390ea05ff52c8825681d2329b780ec9
62c340760c5a7c37c0c81aa4dd75583de13c8ef1
fda121a9cc7ecf9808efb26d8070a0c74060408b
0ebfe7c3126df8f6bc5b721053369065fa2d0c8c
a44a873e11de99a6e31609f8f6075e0c46eb7006
3cb4ed72e76df72af139744cf3215593004db674
959076c596c77999a4ca5fd1d0b2403ae43d0c29
5d106f16b972884fb81c7dac338eeeb09d6c35b9
We cannot bisect more!

Some of the individual commits don't build with clang-12 but looks like that's to be expected.

[dvyukov]

Hi David,

Thanks for reporting. I've mailed https://reviews.llvm.org/D107888. I don't have an aarch64 machine, but I hope it will fix it.

compiler-rt/lib/tsan/rtl/tsan_platform.h

struct MappingGoS390x {
   static const uptr kHeapMemBeg = 0;
   static const uptr kHeapMemEnd = 0;
   static const uptr kVdsoBeg = 0;
   static const uptr kShadowMsk = 0;
   static const uptr kShadowXor = 0;
   static const uptr kShadowAdd = 0x400000000000ull;
 };
 
-#if defined(__x86_64__)
-#  define HAS_48_BIT_ADDRESS_SPACE 1
-#elif SANITIZER_IOSSIM  // arm64 iOS simulators (order of #if matters)
-#  define HAS_48_BIT_ADDRESS_SPACE 1
-#elif SANITIZER_IOS  // arm64 iOS devices (order of #if matters)
-#  define HAS_48_BIT_ADDRESS_SPACE 0
-#elif SANITIZER_MAC  // arm64 macOS (order of #if matters)
-#  define HAS_48_BIT_ADDRESS_SPACE 1
-#else
-#  define HAS_48_BIT_ADDRESS_SPACE 0
-#endif
-
-#if !SANITIZER_GO
+extern uptr vmaSize;
 
-#  if HAS_48_BIT_ADDRESS_SPACE
-typedef Mapping48AddressSpace Mapping;
+template <typename Func, typename Arg>
+ALWAYS_INLINE auto SelectMapping(Arg arg) {
+#if SANITIZER_GO
+#  if defined(__powerpc64__)
+  switch (vmaSize) {
+    case 46:
+      return Func::template Apply<MappingGoPPC64_46>(arg);
+    case 47:
+      return Func::template Apply<MappingGoPPC64_47>(arg);
+  }
 #  elif defined(__mips64)
-typedef MappingMips64_40 Mapping40;
-#    define TSAN_RUNTIME_VMA 1
-#  elif defined(__aarch64__) && defined(__APPLE__)
-typedef MappingAppleAarch64 Mapping;
-#  elif defined(__aarch64__) && !defined(__APPLE__)
-// AArch64 supports multiple VMA which leads to multiple address transformation
-// functions.  To support these multiple VMAS transformations and mappings TSAN
-// runtime for AArch64 uses an external memory read (vmaSize) to select which
-// mapping to use.  Although slower, it make a same instrumented binary run on
-// multiple kernels.
-typedef MappingAarch64_39 Mapping39;
-typedef MappingAarch64_42 Mapping42;
-typedef MappingAarch64_48 Mapping48;
-// Indicates the runtime will define the memory regions at runtime.
-#    define TSAN_RUNTIME_VMA 1
-// Indicates that mapping defines a mid range memory segment.
-#  elif defined(__powerpc64__)
-// PPC64 supports multiple VMA which leads to multiple address transformation
-// functions.  To support these multiple VMAS transformations and mappings TSAN
-// runtime for PPC64 uses an external memory read (vmaSize) to select which
-// mapping to use.  Although slower, it make a same instrumented binary run on
-// multiple kernels.
-typedef MappingPPC64_44 Mapping44;
-typedef MappingPPC64_46 Mapping46;
-typedef MappingPPC64_47 Mapping47;
-// Indicates the runtime will define the memory regions at runtime.
-#    define TSAN_RUNTIME_VMA 1
+  return Func::template Apply<MappingGoMips64_47>(arg);
 #  elif defined(__s390x__)
-typedef MappingS390x Mapping;
-#  endif
-#elif SANITIZER_GO && !SANITIZER_WINDOWS && HAS_48_BIT_ADDRESS_SPACE
-typedef MappingGo48 Mapping;
-#elif SANITIZER_GO && SANITIZER_WINDOWS
-typedef MappingGoWindows Mapping;
-#elif SANITIZER_GO && defined(__powerpc64__)
-/* Only Mapping46 and Mapping47 are currently supported for powercp64 on Go. */
-typedef MappingGoPPC64_46 Mapping46;
-typedef MappingGoPPC64_47 Mapping47;
-#  define TSAN_RUNTIME_VMA 1
-#elif SANITIZER_GO && defined(__aarch64__)
-typedef MappingGoAarch64 Mapping;
-// Indicates the runtime will define the memory regions at runtime.
-#  define TSAN_RUNTIME_VMA 1
-#elif SANITIZER_GO && defined(__mips64)
-typedef MappingGoMips64_47 Mapping47;
-#  define TSAN_RUNTIME_VMA 1
-#elif SANITIZER_GO && defined(__s390x__)
-typedef MappingGoS390x Mapping;
-#else
-#  error "Unknown platform"
-#endif
-
-#ifdef TSAN_RUNTIME_VMA
-extern uptr vmaSize;
-#endif
-
-template <typename Func, typename Arg>
-ALWAYS_INLINE auto SelectMapping(Arg arg) {
-#if defined(__aarch64__) && !defined(__APPLE__) && !SANITIZER_GO
+  return Func::template Apply<MappingGoS390x>(arg);
+#  elif defined(__aarch64__)
+  return Func::template Apply<MappingGoAarch64>(arg);
+#  elif SANITIZER_WINDOWS
+  return Func::template Apply<MappingGoWindows>(arg);
+#  else
+  return Func::template Apply<MappingGo48>(arg);
+#  endif
+#else  // SANITIZER_GO
+#  if defined(__x86_64__) || defined(SANITIZER_IOSSIM) || \
+      SANITIZER_MAC && !SANITIZER_IOS
+  return Func::template Apply<Mapping48AddressSpace>(arg);
+#  elif defined(__aarch64__) && defined(__APPLE__)
+  return Func::template Apply<MappingAppleAarch64>(arg);
+#  elif defined(__aarch64__) && !defined(__APPLE__)
   switch (vmaSize) {
     case 39:
-      return Func::template Apply<Mapping39>(arg);
+      return Func::template Apply<MappingAarch64_39>(arg);
     case 42:
-      return Func::template Apply<Mapping42>(arg);
+      return Func::template Apply<MappingAarch64_42>(arg);
     case 48:
-      return Func::template Apply<Mapping48>(arg);
+      return Func::template Apply<MappingAarch64_48>(arg);
   }
-  DCHECK(0);
-  return 0;
-#elif defined(__powerpc64__)
+#  elif defined(__powerpc64__)
   switch (vmaSize) {
-#  if !SANITIZER_GO
     case 44:
-      return Func::template Apply<Mapping44>(arg);
-#  endif
+      return Func::template Apply<MappingPPC64_44>(arg);
     case 46:
-      return Func::template Apply<Mapping46>(arg);
+      return Func::template Apply<MappingPPC64_46>(arg);
     case 47:
-      return Func::template Apply<Mapping47>(arg);
+      return Func::template Apply<MappingPPC64_47>(arg);
   }
-  DCHECK(0);
-  return 0;
-#elif defined(__mips64)
-  switch (vmaSize) {
-#  if !SANITIZER_GO
-    case 40:
-      return Func::template Apply<Mapping40>(arg);
+#  elif defined(__mips64)
+  return Func::template Apply<MappingMips64_40>(arg);
+#  elif defined(__s390x__)
+  return Func::template Apply<MappingS390x>(arg);
 #  else
-    case 47:
-      return Func::template Apply<Mapping47>(arg);
+#    error "unsupported platform"
 #  endif
-  }
-  DCHECK(0);
-  return 0;
-#else
-  return Func::template Apply<Mapping>(arg);
 #endif
+  Die();
 }
 
 template <typename Func>
 void ForEachMapping() {
   Func::template Apply<Mapping48AddressSpace>();
   Func::template Apply<MappingMips64_40>();
   Func::template Apply<MappingAppleAarch64>();
   Func::template Apply<MappingAarch64_39>();

compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp

 
 namespace __tsan {
 
 #if INIT_LONGJMP_XOR_KEY
 static void InitializeLongjmpXorKey();
 static uptr longjmp_xor_key;
 #endif
 
-#ifdef TSAN_RUNTIME_VMA
 // Runtime detected VMA size.
 uptr vmaSize;
-#endif
 
 enum {
   MemTotal  = 0,
   MemShadow = 1,
   MemMeta   = 2,
   MemFile   = 3,
   MemMmap   = 4,
   MemTrace  = 5,

 
 void InitializeShadowMemoryPlatform() {
   MapRodata();
 }
 
 #endif  // #if !SANITIZER_GO
 
 void InitializePlatformEarly() {
-#ifdef TSAN_RUNTIME_VMA
   vmaSize =
     (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1);
 #if defined(__aarch64__)
 # if !SANITIZER_GO
   if (vmaSize != 39 && vmaSize != 42 && vmaSize != 48) {
     Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
     Printf("FATAL: Found %zd - Supported 39, 42 and 48\n", vmaSize);
     Die();

 # else
   if (vmaSize != 47) {
     Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
     Printf("FATAL: Found %zd - Supported 47\n", vmaSize);
     Die();
   }
 # endif
 #endif
-#endif
 }
 
 void InitializePlatform() {
   DisableCoreDumperIfNecessary();
 
   // Go maps shadow memory lazily and works fine with limited address space.
   // Unlimited stack is not a problem as well, because the executable
   // is not compiled with -pie.