From c6000317f1cef3069315de81f918e1ac556e2ace Mon Sep 17 00:00:00 2001
From: Chris Mihelich <cmihelic@google.com>
Date: Fri, 7 Jun 2024 11:34:21 -0700
Subject: Demangle <extended-qualifier> in types, e.g., U5AS128 for
 address_space(128).

PiperOrigin-RevId: 641310017
Change-Id: I0f10a2a1965e842db4efda455e0cdfbeb6656fa5
---
 absl/debugging/internal/demangle.cc      | 24 +++++++++++++++-------
 absl/debugging/internal/demangle_test.cc | 34 ++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/absl/debugging/internal/demangle.cc b/absl/debugging/internal/demangle.cc
index 812efe13..6507afb5 100644
--- a/absl/debugging/internal/demangle.cc
+++ b/absl/debugging/internal/demangle.cc
@@ -598,6 +598,7 @@ static bool ParseCtorDtorName(State *state);
 static bool ParseDecltype(State *state);
 static bool ParseType(State *state);
 static bool ParseCVQualifiers(State *state);
+static bool ParseExtendedQualifier(State *state);
 static bool ParseBuiltinType(State *state);
 static bool ParseVendorExtendedType(State *state);
 static bool ParseFunctionType(State *state);
@@ -1322,7 +1323,6 @@ static bool ParseDecltype(State *state) {
 //        ::= O <type>   # rvalue reference-to (C++0x)
 //        ::= C <type>   # complex pair (C 2000)
 //        ::= G <type>   # imaginary (C 2000)
-//        ::= U <source-name> <type>  # vendor extended type qualifier
 //        ::= <builtin-type>
 //        ::= <function-type>
 //        ::= <class-enum-type>  # note: just an alias for <name>
@@ -1378,12 +1378,6 @@ static bool ParseType(State *state) {
   }
   state->parse_state = copy;
 
-  if (ParseOneCharToken(state, 'U') && ParseSourceName(state) &&
-      ParseType(state)) {
-    return true;
-  }
-  state->parse_state = copy;
-
   if (ParseBuiltinType(state) || ParseFunctionType(state) ||
       ParseClassEnumType(state) || ParseArrayType(state) ||
       ParsePointerToMemberType(state) || ParseDecltype(state) ||
@@ -1427,19 +1421,35 @@ static bool ParseType(State *state) {
   return ParseLongToken(state, "_SUBSTPACK_");
 }
 
+// <qualifiers> ::= <extended-qualifier>* <CV-qualifiers>
 // <CV-qualifiers> ::= [r] [V] [K]
+//
 // We don't allow empty <CV-qualifiers> to avoid infinite loop in
 // ParseType().
 static bool ParseCVQualifiers(State *state) {
   ComplexityGuard guard(state);
   if (guard.IsTooComplex()) return false;
   int num_cv_qualifiers = 0;
+  while (ParseExtendedQualifier(state)) ++num_cv_qualifiers;
   num_cv_qualifiers += ParseOneCharToken(state, 'r');
   num_cv_qualifiers += ParseOneCharToken(state, 'V');
   num_cv_qualifiers += ParseOneCharToken(state, 'K');
   return num_cv_qualifiers > 0;
 }
 
+// <extended-qualifier> ::= U <source-name> [<template-args>]
+static bool ParseExtendedQualifier(State *state) {
+  ComplexityGuard guard(state);
+  if (guard.IsTooComplex()) return false;
+  ParseState copy = state->parse_state;
+  if (ParseOneCharToken(state, 'U') && ParseSourceName(state) &&
+      Optional(ParseTemplateArgs(state))) {
+    return true;
+  }
+  state->parse_state = copy;
+  return false;
+}
+
 // <builtin-type> ::= v, etc.  # single-character builtin types
 //                ::= <vendor-extended-type>
 //                ::= Dd, etc.  # two-character builtin types
diff --git a/absl/debugging/internal/demangle_test.cc b/absl/debugging/internal/demangle_test.cc
index 3285f2ca..9100d5f1 100644
--- a/absl/debugging/internal/demangle_test.cc
+++ b/absl/debugging/internal/demangle_test.cc
@@ -760,6 +760,40 @@ TEST(Demangle, GnuVectorSizeIsADependentOperatorExpression) {
   EXPECT_STREQ("f<>()", tmp);
 }
 
+TEST(Demangle, SimpleAddressSpace) {
+  char tmp[80];
+
+  // Source:
+  //
+  // void f(const int __attribute__((address_space(128)))*) {}
+  //
+  // LLVM demangling:
+  //
+  // f(int const AS128*)
+  //
+  // Itanium ABI 5.1.5.1, "Qualified types", notes that address_space is mangled
+  // nonuniformly as a legacy exception: the number is part of the source-name
+  // if nondependent but is an expression in template-args if dependent.  Thus
+  // it is a convenient test case for both forms.
+  EXPECT_TRUE(Demangle("_Z1fPU5AS128Ki", tmp, sizeof(tmp)));
+  EXPECT_STREQ("f()", tmp);
+}
+
+TEST(Demangle, DependentAddressSpace) {
+  char tmp[80];
+
+  // Source:
+  //
+  // template <int n> void f (const int __attribute__((address_space(n)))*) {}
+  // template void f<128>(const int __attribute__((address_space(128)))*);
+  //
+  // LLVM demangling:
+  //
+  // void f<128>(int AS<128>*)
+  EXPECT_TRUE(Demangle("_Z1fILi128EEvPU2ASIT_Ei", tmp, sizeof(tmp)));
+  EXPECT_STREQ("f<>()", tmp);
+}
+
 TEST(Demangle, TransactionSafeEntryPoint) {
   char tmp[80];
 
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