From 8251d93e823945158afea82c3b53690b6b39a4b4 Mon Sep 17 00:00:00 2001
From: Frank Tang <ftang@chromium.org>
Date: Thu, 12 Nov 2020 15:39:40 -0800
Subject: [PATCH] ICU-21395 Fix UBSan breakage on 8bit of rbbi

---
 icu4c/source/common/rbbitblb.cpp | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/icu4c/source/common/rbbitblb.cpp b/icu4c/source/common/rbbitblb.cpp
index bcbdab9227c..70e260fc08b 100644
--- a/icu4c/source/common/rbbitblb.cpp
+++ b/icu4c/source/common/rbbitblb.cpp
@@ -1402,12 +1402,13 @@ void RBBITableBuilder::exportTable(void *where) {
             U_ASSERT (sd->fAccepting <= 255);
             U_ASSERT (sd->fLookAhead <= 255);
             U_ASSERT (0 <= sd->fTagsIdx && sd->fTagsIdx <= 255);
-            row->r8.fAccepting = sd->fAccepting;
-            row->r8.fLookAhead = sd->fLookAhead;
-            row->r8.fTagsIdx   = sd->fTagsIdx;
+            RBBIStateTableRow8 *r8 = (RBBIStateTableRow8*)row;
+            r8->fAccepting = sd->fAccepting;
+            r8->fLookAhead = sd->fLookAhead;
+            r8->fTagsIdx   = sd->fTagsIdx;
             for (col=0; col<catCount; col++) {
                 U_ASSERT (sd->fDtran->elementAti(col) <= kMaxStateFor8BitsTable);
-                row->r8.fNextState[col] = sd->fDtran->elementAti(col);
+                r8->fNextState[col] = sd->fDtran->elementAti(col);
             }
         } else {
             U_ASSERT (sd->fAccepting <= 0xffff);
@@ -1603,12 +1604,13 @@ void RBBITableBuilder::exportSafeTable(void *where) {
         UnicodeString *rowString = (UnicodeString *)fSafeTable->elementAt(state);
         RBBIStateTableRow   *row = (RBBIStateTableRow *)(table->fTableData + state*table->fRowLen);
         if (use8BitsForSafeTable()) {
-            row->r8.fAccepting = 0;
-            row->r8.fLookAhead = 0;
-            row->r8.fTagsIdx    = 0;
+            RBBIStateTableRow8 *r8 = (RBBIStateTableRow8*)row;
+            r8->fAccepting = 0;
+            r8->fLookAhead = 0;
+            r8->fTagsIdx    = 0;
             for (col=0; col<catCount; col++) {
                 U_ASSERT(rowString->charAt(col) <= kMaxStateFor8BitsTable);
-                row->r8.fNextState[col] = static_cast<uint8_t>(rowString->charAt(col));
+                r8->fNextState[col] = static_cast<uint8_t>(rowString->charAt(col));
             }
         } else {
             row->r16.fAccepting = 0;