Demangle throw and rethrow (tw... and tr).

PiperOrigin-RevId: 640648613
Change-Id: Ifb4c385e629e2649da61b2b49c786a320da05fc7

absl/debugging/internal/demangle.cc

@@ -2014,6 +2014,8 @@ static bool ParseBracedExpression(State *state) {
 //              ::= fr <binary operator-name> <expression>
 //              ::= fL <binary operator-name> <expression> <expression>
 //              ::= fR <binary operator-name> <expression> <expression>
+//              ::= tw <expression>
+//              ::= tr
 //              ::= sr <type> <unqualified-name> <template-args>
 //              ::= sr <type> <unqualified-name>
 //              ::= u <source-name> <template-arg>* E  # vendor extension
@@ -2197,6 +2199,15 @@ static bool ParseExpression(State *state) {
   }
   state->parse_state = copy;
 
+  // tw <expression>: throw e
+  if (ParseTwoCharToken(state, "tw") && ParseExpression(state)) {
+    return true;
+  }
+  state->parse_state = copy;
+
+  // tr: throw (rethrows an exception from the handler that caught it)
+  if (ParseTwoCharToken(state, "tr")) return true;
+
   // Object and pointer member access expressions.
   //
   // <expression> ::= (dt | pt) <expression> <unresolved-name>

absl/debugging/internal/demangle_test.cc

@@ -1177,6 +1177,36 @@ TEST(Demangle, NoexceptExpression) {
   EXPECT_STREQ("f<>()", tmp);
 }
 
+TEST(Demangle, UnaryThrow) {
+  char tmp[80];
+
+  // Source:
+  //
+  // template <bool b> decltype(b ? throw b : 0) f() { return 0; }
+  // template decltype(false ? throw false : 0) f<false>();
+  //
+  // Full LLVM demangling of the instantiation of f:
+  //
+  // decltype(false ? throw false : 0) f<false>()
+  EXPECT_TRUE(Demangle("_Z1fILb0EEDTquT_twT_Li0EEv", tmp, sizeof(tmp)));
+  EXPECT_STREQ("f<>()", tmp);
+}
+
+TEST(Demangle, NullaryThrow) {
+  char tmp[80];
+
+  // Source:
+  //
+  // template <bool b> decltype(b ? throw : 0) f() { return 0; }
+  // template decltype(false ? throw : 0) f<false>();
+  //
+  // Full LLVM demangling of the instantiation of f:
+  //
+  // decltype(false ? throw : 0) f<false>()
+  EXPECT_TRUE(Demangle("_Z1fILb0EEDTquT_trLi0EEv", tmp, sizeof(tmp)));
+  EXPECT_STREQ("f<>()", tmp);
+}
+
 TEST(Demangle, ThreadLocalWrappers) {
   char tmp[80];