[HWASan] link to doc in reports on Android

[eugenis]

LGTM

compiler-rt/lib/hwasan/hwasan_report.cpp

108

HWASan (because Sanitizer)

[fmayer]

spelling

compiler-rt/lib/hwasan/hwasan_report.cpp

 
 static StackTrace GetStackTraceFromId(u32 id) {
   CHECK(id);
   StackTrace res = StackDepotGet(id);
   CHECK(res.trace);
   return res;
 }
 
+static void MaybePrintAndroidHelpUrl() {
+#if SANITIZER_ANDROID
+  Printf(
+      "Learn more about HWAsan reports: "
+      "https://source.android.com/docs/security/test/memory-safety/"
+      "hwasan-reports\n");
+#endif
+}
+
 // A RAII object that holds a copy of the current thread stack ring buffer.
 // The actual stack buffer may change while we are iterating over it (for
 // example, Printf may call syslog() which can itself be built with hwasan).
 class SavedStackAllocations {
  public:
   SavedStackAllocations(StackAllocationsRingBuffer *rb) {
     uptr size = rb->size() * sizeof(uptr);
     void *storage =
void ReportInvalidFree(StackTrace *stack, uptr tagged_addr) {
 
   stack->Print();
 
   PrintAddressDescription(tagged_addr, 0, nullptr);
 
   if (tag_ptr)
     PrintTagsAroundAddr(tag_ptr);
 
+  MaybePrintAndroidHelpUrl();
   ReportErrorSummary(bug_type, stack);
 }
 
 void ReportTailOverwritten(StackTrace *stack, uptr tagged_addr, uptr orig_size,
                            const u8 *expected) {
   uptr tail_size = kShadowAlignment - (orig_size % kShadowAlignment);
   u8 actual_expected[kShadowAlignment];
   internal_memcpy(actual_expected, expected, tail_size);
s.append("\nThis error occurs when a buffer overflow overwrites memory\n"
     "To disable this feature set HWASAN_OPTIONS=free_checks_tail_magic=0\n",
     kShadowAlignment, SanitizerToolName);
   Printf("%s", s.data());
   GetCurrentThread()->Announce();
 
   tag_t *tag_ptr = reinterpret_cast<tag_t*>(MemToShadow(untagged_addr));
   PrintTagsAroundAddr(tag_ptr);
 
+  MaybePrintAndroidHelpUrl();
   ReportErrorSummary(bug_type, stack);
 }
 
 void ReportTagMismatch(StackTrace *stack, uptr tagged_addr, uptr access_size,
                        bool is_store, bool fatal, uptr *registers_frame) {
   ScopedReport R(fatal);
   SavedStackAllocations current_stack_allocations(
       GetCurrentThread()->stack_allocations());
PrintAddressDescription(tagged_addr, access_size,
                           current_stack_allocations.get());
   t->Announce();
 
   PrintTagsAroundAddr(tag_ptr);
 
   if (registers_frame)
     ReportRegisters(registers_frame, pc);
 
+  MaybePrintAndroidHelpUrl();
   ReportErrorSummary(bug_type, stack);
 }
 
 // See the frame breakdown defined in __hwasan_tag_mismatch (from
 // hwasan_tag_mismatch_{aarch64,riscv64}.S).
 void ReportRegisters(uptr *frame, uptr pc) {
   Printf("Registers where the failure occurred (pc %p):\n", pc);