2 files changed, 55 insertions, 0 deletions
diff --git a/absl/debugging/internal/demangle.cc b/absl/debugging/internal/demangle.cc
index 184d89fb..26421c0e 100644
--- a/absl/debugging/internal/demangle.cc
+++ b/absl/debugging/internal/demangle.cc
@@ -1453,12 +1453,43 @@ static bool ParseExtendedQualifier(State *state) {
 // <builtin-type> ::= v, etc.  # single-character builtin types
 //                ::= <vendor-extended-type>
 //                ::= Dd, etc.  # two-character builtin types
+//                ::= DB (<number> | <expression>) _  # _BitInt(N)
+//                ::= DU (<number> | <expression>) _  # unsigned _BitInt(N)
 //
 // Not supported:
 //                ::= DF <number> _ # _FloatN (N bits)
 static bool ParseBuiltinType(State *state) {
   ComplexityGuard guard(state);
   if (guard.IsTooComplex()) return false;
+  ParseState copy = state->parse_state;
+
+  // DB (<number> | <expression>) _  # _BitInt(N)
+  // DU (<number> | <expression>) _  # unsigned _BitInt(N)
+  if (ParseTwoCharToken(state, "DB") ||
+      (ParseTwoCharToken(state, "DU") && MaybeAppend(state, "unsigned "))) {
+    bool append = state->parse_state.append;
+    DisableAppend(state);
+    int number = -1;
+    if (!ParseNumber(state, &number) && !ParseExpression(state)) {
+      state->parse_state = copy;
+      return false;
+    }
+    RestoreAppend(state, append);
+
+    if (!ParseOneCharToken(state, '_')) {
+      state->parse_state = copy;
+      return false;
+    }
+
+    MaybeAppend(state, "_BitInt(");
+    if (number >= 0) {
+      MaybeAppendDecimal(state, number);
+    } else {
+      MaybeAppend(state, "?");  // the best we can do for dependent sizes
+    }
+    MaybeAppend(state, ")");
+    return true;
+  }
 
   for (const AbbrevPair *p = kBuiltinTypeList; p->abbrev != nullptr; ++p) {
     // Guaranteed only 1- or 2-character strings in kBuiltinTypeList.
diff --git a/absl/debugging/internal/demangle_test.cc b/absl/debugging/internal/demangle_test.cc
index 111e895c..c702e189 100644
--- a/absl/debugging/internal/demangle_test.cc
+++ b/absl/debugging/internal/demangle_test.cc
@@ -660,6 +660,30 @@ TEST(Demangle, ComplexFloatingPointLiterals) {
   EXPECT_STREQ("f<>()", tmp);
 }
 
+TEST(Demangle, SimpleSignedBitInt) {
+  char tmp[80];
+
+  // S::operator _BitInt(256)() const
+  EXPECT_TRUE(Demangle("_ZNK1ScvDB256_Ev", tmp, sizeof(tmp)));
+  EXPECT_STREQ("S::operator _BitInt(256)()", tmp);
+}
+
+TEST(Demangle, SimpleUnsignedBitInt) {
+  char tmp[80];
+
+  // S::operator unsigned _BitInt(256)() const
+  EXPECT_TRUE(Demangle("_ZNK1ScvDU256_Ev", tmp, sizeof(tmp)));
+  EXPECT_STREQ("S::operator unsigned _BitInt(256)()", tmp);
+}
+
+TEST(Demangle, DependentBitInt) {
+  char tmp[80];
+
+  // S::operator _BitInt(256)<256>() const
+  EXPECT_TRUE(Demangle("_ZNK1ScvDBT__ILi256EEEv", tmp, sizeof(tmp)));
+  EXPECT_STREQ("S::operator _BitInt(?)<>()", tmp);
+}
+
 TEST(Demangle, GlobalInitializers) {
   char tmp[80];