[TSan] Fix potentially problematic shadow end calculations

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

@@ -122,7 +122,6 @@ void __tsan_java_move(jptr src, jptr dst, jptr size) {
   DCHECK_GE(dst, jctx->heap_begin);
   DCHECK_LE(dst + size, jctx->heap_begin + jctx->heap_size);
   DCHECK_NE(dst, src);
-  DCHECK_NE(size, 0);
 
   // Assuming it's not running concurrently with threads that do
   // memory accesses and mutex operations (stop-the-world phase).
@@ -132,7 +131,7 @@ void __tsan_java_move(jptr src, jptr dst, jptr size) {
   // We used to move shadow from src to dst, but the trace format does not
   // support that anymore as it contains addresses of accesses.
   RawShadow *d = MemToShadow(dst);
-  RawShadow *dend = MemToShadow(dst + size);
+  RawShadow *dend = MemToEndShadow(dst + size);
   ShadowSet(d, dend, Shadow::kEmpty);
 }
 

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

@@ -968,6 +968,24 @@ RawShadow *MemToShadow(uptr x) {
   return reinterpret_cast<RawShadow *>(SelectMapping<MemToShadowImpl>(x));
 }
 
+struct MemToEndShadowImpl {
+  template <typename Mapping>
+  static uptr Apply(uptr x) {
+    return (((x + kShadowCell - 1) &
+             ~(Mapping::kShadowMsk | (kShadowCell - 1))) ^
+            Mapping::kShadowXor) *
+               kShadowMultiplier +
+           Mapping::kShadowAdd;
+  }
+};
+
+// If addr % kShadowCell == 0, then MemToEndShadow(addr) == MemToShadow(addr)
+// Otherwise, MemToEndShadow(addr) == MemToShadow(addr) + kShadowCnt
+ALWAYS_INLINE
+RawShadow *MemToEndShadow(uptr x) {
+  return reinterpret_cast<RawShadow *>(SelectMapping<MemToEndShadowImpl>(x));
+}
+
 struct MemToMetaImpl {
   template <typename Mapping>
   static u32 *Apply(uptr x) {

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

@@ -195,7 +195,7 @@ static NOINLINE void MapRodata(char* buffer, uptr size) {
         !segment.IsWritable() && IsAppMem(segment.start)) {
       // Assume it's .rodata
       char *shadow_start = (char *)MemToShadow(segment.start);
-      char *shadow_end = (char *)MemToShadow(segment.end);
+      char *shadow_end = (char *)MemToEndShadow(segment.end);
       for (char *p = shadow_start; p < shadow_end;
            p += marker.size() * sizeof(RawShadow)) {
         internal_mmap(

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

@@ -532,7 +532,7 @@ static void StopBackgroundThread() {
 
 void DontNeedShadowFor(uptr addr, uptr size) {
   ReleaseMemoryPagesToOS(reinterpret_cast<uptr>(MemToShadow(addr)),
-                         reinterpret_cast<uptr>(MemToShadow(addr + size)));
+                         reinterpret_cast<uptr>(MemToEndShadow(addr + size)));
 }
 
 #if !SANITIZER_GO
@@ -588,12 +588,12 @@ void MapShadow(uptr addr, uptr size) {
   // CHECK_EQ(addr, addr & ~((64 << 10) - 1));  // windows wants 64K alignment
   const uptr kPageSize = GetPageSizeCached();
   uptr shadow_begin = RoundDownTo((uptr)MemToShadow(addr), kPageSize);
-  uptr shadow_end = RoundUpTo((uptr)MemToShadow(addr + size), kPageSize);
+  uptr shadow_end = RoundUpTo((uptr)MemToEndShadow(addr + size), kPageSize);
   if (!MmapFixedNoReserve(shadow_begin, shadow_end - shadow_begin, "shadow"))
     Die();
 #else
   uptr shadow_begin = RoundDownTo((uptr)MemToShadow(addr), (64 << 10));
-  uptr shadow_end = RoundUpTo((uptr)MemToShadow(addr + size), (64 << 10));
+  uptr shadow_end = RoundUpTo((uptr)MemToEndShadow(addr + size), (64 << 10));
   VPrintf(2, "MapShadow for (0x%zx-0x%zx), begin/end: (0x%zx-0x%zx)\n",
           addr, addr + size, shadow_begin, shadow_end);
 

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

@@ -684,16 +684,15 @@ void MemoryAccessRangeT(ThreadState* thr, uptr pc, uptr addr, uptr size) {
     DCHECK(IsShadowMem(shadow_mem));
   }
 
-  RawShadow* shadow_mem_end = reinterpret_cast<RawShadow*>(
-      reinterpret_cast<uptr>(shadow_mem) + size * kShadowMultiplier - 1);
-  if (!IsShadowMem(shadow_mem_end)) {
-    Printf("Bad shadow end addr: %p (%p)\n", shadow_mem_end,
+  RawShadow* shadow_mem_end = MemToEndShadow(addr + size);
+  if (size > 0 && !IsShadowMem(shadow_mem_end - 1)) {
+    Printf("Bad shadow end addr: %p (%p)\n", shadow_mem_end - 1,
            (void*)(addr + size - 1));
     Printf(
         "Shadow start addr (ok): %p (%p); size: 0x%zx; kShadowMultiplier: "
         "%zx\n",
         shadow_mem, (void*)addr, size, kShadowMultiplier);
-    DCHECK(IsShadowMem(shadow_mem_end));
+    DCHECK(IsShadowMem(shadow_mem_end - 1));
   }
 #endif