From 6e607350cccd7e5157ca4b522489920db45c8e8b Mon Sep 17 00:00:00 2001
From: Chris Mihelich <cmihelic@google.com>
Date: Thu, 6 Jun 2024 15:47:25 -0700
Subject: Demangle C++11 user-defined literal operator functions.

PiperOrigin-RevId: 641046309
Change-Id: Iaa2564a60035421969c2cd6074a457980083cbd2
---
 absl/debugging/internal/demangle.cc      | 10 ++++++++--
 absl/debugging/internal/demangle_test.cc | 14 ++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/absl/debugging/internal/demangle.cc b/absl/debugging/internal/demangle.cc
index 42c10bbe..8b76ce01 100644
--- a/absl/debugging/internal/demangle.cc
+++ b/absl/debugging/internal/demangle.cc
@@ -14,8 +14,6 @@
 
 // For reference check out:
 // https://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangling
-//
-// Note that we only have partial C++11 support yet.
 
 #include "absl/debugging/internal/demangle.h"
 
@@ -1044,6 +1042,7 @@ static bool ParseIdentifier(State *state, size_t length) {
 
 // <operator-name> ::= nw, and other two letters cases
 //                 ::= cv <type>  # (cast)
+//                 ::= li <source-name>  # C++11 user-defined literal
 //                 ::= v  <digit> <source-name> # vendor extended operator
 static bool ParseOperatorName(State *state, int *arity) {
   ComplexityGuard guard(state);
@@ -1063,6 +1062,13 @@ static bool ParseOperatorName(State *state, int *arity) {
   }
   state->parse_state = copy;
 
+  // Then user-defined literals.
+  if (ParseTwoCharToken(state, "li") && MaybeAppend(state, "operator\"\" ") &&
+      ParseSourceName(state)) {
+    return true;
+  }
+  state->parse_state = copy;
+
   // Then vendor extended operators.
   if (ParseOneCharToken(state, 'v') && ParseDigit(state, arity) &&
       ParseSourceName(state)) {
diff --git a/absl/debugging/internal/demangle_test.cc b/absl/debugging/internal/demangle_test.cc
index 68ab8a3c..108642a8 100644
--- a/absl/debugging/internal/demangle_test.cc
+++ b/absl/debugging/internal/demangle_test.cc
@@ -1035,6 +1035,20 @@ TEST(Demangle, SizeofPackInvolvingAnAliasTemplate) {
   EXPECT_STREQ("f<>()", tmp);
 }
 
+TEST(Demangle, UserDefinedLiteral) {
+  char tmp[80];
+
+  // Source:
+  //
+  // unsigned long long operator""_lit(unsigned long long x) { return x; }
+  //
+  // LLVM demangling:
+  //
+  // operator"" _lit(unsigned long long)
+  EXPECT_TRUE(Demangle("_Zli4_lity", tmp, sizeof(tmp)));
+  EXPECT_STREQ("operator\"\" _lit()", tmp);
+}
+
 TEST(Demangle, Spaceship) {
   char tmp[80];
 
-- 
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