From 54e1f14c6f9b1a764ffdf8c1aea7e823f95f3d01 Mon Sep 17 00:00:00 2001
From: Chris Mihelich <cmihelic@google.com>
Date: Wed, 5 Jun 2024 16:33:54 -0700
Subject: Demangle object new-expressions, [gs] nw ....

PiperOrigin-RevId: 640688552
Change-Id: I843e5aed55f90eeb89e007389390d0aba705a3fe
---
 absl/debugging/internal/demangle.cc      | 28 +++++++++++
 absl/debugging/internal/demangle_test.cc | 80 ++++++++++++++++++++++++++++++++
 2 files changed, 108 insertions(+)

(limited to 'absl/debugging')

diff --git a/absl/debugging/internal/demangle.cc b/absl/debugging/internal/demangle.cc
index 7fe8439b..761bde13 100644
--- a/absl/debugging/internal/demangle.cc
+++ b/absl/debugging/internal/demangle.cc
@@ -618,6 +618,7 @@ static bool ParseUnionSelector(State* state);
 static bool ParseFunctionParam(State* state);
 static bool ParseBracedExpression(State *state);
 static bool ParseExpression(State *state);
+static bool ParseInitializer(State *state);
 static bool ParseExprPrimary(State *state);
 static bool ParseExprCastValueAndTrailingE(State *state);
 static bool ParseQRequiresClauseExpr(State *state);
@@ -1993,6 +1994,8 @@ static bool ParseBracedExpression(State *state) {
 //              ::= cv <type> _ <expression>* E # type (expr-list)
 //              ::= tl <type> <braced-expression>* E
 //              ::= il <braced-expression>* E
+//              ::= [gs] nw <expression>* _ <type> E
+//              ::= [gs] nw <expression>* _ <type> <initializer>
 //              ::= dc <type> <expression>
 //              ::= sc <type> <expression>
 //              ::= cc <type> <expression>
@@ -2088,6 +2091,17 @@ static bool ParseExpression(State *state) {
   }
   state->parse_state = copy;
 
+  // <expression> ::= [gs] nw <expression>* _ <type> E
+  //              ::= [gs] nw <expression>* _ <type> <initializer>
+  if (Optional(ParseTwoCharToken(state, "gs")) &&
+      ParseTwoCharToken(state, "nw") &&
+      ZeroOrMore(ParseExpression, state) && ParseOneCharToken(state, '_') &&
+      ParseType(state) &&
+      (ParseOneCharToken(state, 'E') || ParseInitializer(state))) {
+    return true;
+  }
+  state->parse_state = copy;
+
   // dynamic_cast, static_cast, const_cast, reinterpret_cast.
   //
   // <expression> ::= (dc | sc | cc | rc) <type> <expression>
@@ -2272,6 +2286,20 @@ static bool ParseExpression(State *state) {
   return ParseUnresolvedName(state);
 }
 
+// <initializer> ::= pi <expression>* E
+static bool ParseInitializer(State *state) {
+  ComplexityGuard guard(state);
+  if (guard.IsTooComplex()) return false;
+  ParseState copy = state->parse_state;
+
+  if (ParseTwoCharToken(state, "pi") && ZeroOrMore(ParseExpression, state) &&
+      ParseOneCharToken(state, 'E')) {
+    return true;
+  }
+  state->parse_state = copy;
+  return false;
+}
+
 // <expr-primary> ::= L <type> <(value) number> E
 //                ::= L <type> <(value) float> E
 //                ::= L <mangled-name> E
diff --git a/absl/debugging/internal/demangle_test.cc b/absl/debugging/internal/demangle_test.cc
index 7d455651..747bc06c 100644
--- a/absl/debugging/internal/demangle_test.cc
+++ b/absl/debugging/internal/demangle_test.cc
@@ -1068,6 +1068,86 @@ TEST(Demangle, BracedListImplicitlyConstructingAClassObject) {
   EXPECT_STREQ("f<>()", tmp);
 }
 
+TEST(Demangle, SimpleNewExpression) {
+  char tmp[80];
+
+  // Source:
+  //
+  // template <class T> decltype(T{*new T}) f() { return T{}; }
+  // template decltype(int{*new int}) f<int>();
+  //
+  // Full LLVM demangling of the instantiation of f:
+  //
+  // decltype(int{*(new int)}) f<int>()
+  EXPECT_TRUE(Demangle("_Z1fIiEDTtlT_denw_S0_EEEv", tmp, sizeof(tmp)));
+  EXPECT_STREQ("f<>()", tmp);
+}
+
+TEST(Demangle, NewExpressionWithEmptyParentheses) {
+  char tmp[80];
+
+  // Source:
+  //
+  // template <class T> decltype(T{*new T()}) f() { return T{}; }
+  // template decltype(int{*new int()}) f<int>();
+  //
+  // Full LLVM demangling of the instantiation of f:
+  //
+  // decltype(int{*(new int)}) f<int>()
+  EXPECT_TRUE(Demangle("_Z1fIiEDTtlT_denw_S0_piEEEv", tmp, sizeof(tmp)));
+  EXPECT_STREQ("f<>()", tmp);
+}
+
+TEST(Demangle, NewExpressionWithNonemptyParentheses) {
+  char tmp[80];
+
+  // Source:
+  //
+  // template <class T> decltype(T{*new T(42)}) f() { return T{}; }
+  // template decltype(int{*new int(42)}) f<int>();
+  //
+  // Full LLVM demangling of the instantiation of f:
+  //
+  // decltype(int{*(new int(42))}) f<int>()
+  EXPECT_TRUE(Demangle("_Z1fIiEDTtlT_denw_S0_piLi42EEEEv", tmp, sizeof(tmp)));
+  EXPECT_STREQ("f<>()", tmp);
+}
+
+TEST(Demangle, PlacementNewExpression) {
+  char tmp[80];
+
+  // Source:
+  //
+  // #include <new>
+  //
+  // template <class T> auto f(T t) -> decltype(T{*new (&t) T(42)}) {
+  //   return t;
+  // }
+  // template auto f<int>(int t) -> decltype(int{*new (&t) int(42)});
+  //
+  // Full LLVM demangling of the instantiation of f:
+  //
+  // decltype(int{*(new(&fp) int(42))}) f<int>(int)
+  EXPECT_TRUE(Demangle("_Z1fIiEDTtlT_denwadfp__S0_piLi42EEEES0_",
+                       tmp, sizeof(tmp)));
+  EXPECT_STREQ("f<>()", tmp);
+}
+
+TEST(Demangle, GlobalScopeNewExpression) {
+  char tmp[80];
+
+  // Source:
+  //
+  // template <class T> decltype(T{*::new T}) f() { return T{}; }
+  // template decltype(int{*::new int}) f<int>();
+  //
+  // Full LLVM demangling of the instantiation of f:
+  //
+  // decltype(int{*(::new int)}) f<int>()
+  EXPECT_TRUE(Demangle("_Z1fIiEDTtlT_degsnw_S0_EEEv", tmp, sizeof(tmp)));
+  EXPECT_STREQ("f<>()", tmp);
+}
+
 TEST(Demangle, ReferenceQualifiedFunctionTypes) {
   char tmp[80];
 
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