From b1a7f3c741a260df1c0e9e9f62518601f72ac2a7 Mon Sep 17 00:00:00 2001
From: Erik Pilkington <erik.pilkington@gmail.com>
Date: Sat, 10 Mar 2018 21:31:15 +0000
Subject: [PATCH] [demangler] Support for structured bindings.

llvm-svn: 327226
---
 libcxxabi/src/cxa_demangle.cpp        | 29 ++++++++++++++++++++++++++---
 libcxxabi/test/test_demangle.pass.cpp |  5 ++++-
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/libcxxabi/src/cxa_demangle.cpp b/libcxxabi/src/cxa_demangle.cpp
index ffd887a..5c313cb 100644
--- a/libcxxabi/src/cxa_demangle.cpp
+++ b/libcxxabi/src/cxa_demangle.cpp
@@ -197,6 +197,7 @@ public:
     KDtorName,
     KUnnamedTypeName,
     KClosureTypeName,
+    KStructuredBindingName,
     KExpr,
     KBracedExpr,
     KBracedRangeExpr,
@@ -1337,6 +1338,19 @@ public:
   }
 };
 
+class StructuredBindingName : public Node {
+  NodeArray Bindings;
+public:
+  StructuredBindingName(NodeArray Bindings_)
+      : Node(KStructuredBindingName), Bindings(Bindings_) {}
+
+  void printLeft(OutputStream &S) const override {
+    S += "'structured-binding'[";
+    Bindings.printWithComma(S);
+    S += ']';
+  }
+};
+
 // -- Expression Nodes --
 
 struct Expr : public Node {
@@ -2217,7 +2231,7 @@ Node *Db::parseUnscopedName(NameState *State) {
 //                    ::= <ctor-dtor-name>
 //                    ::= <source-name>
 //                    ::= <unnamed-type-name>
-// FIXME:             ::= DC <source-name>+ E      # structured binding declaration
+//                    ::= DC <source-name>+ E      # structured binding declaration
 Node *Db::parseUnqualifiedName(NameState *State) {
  // <ctor-dtor-name>s are special-cased in parseNestedName().
  Node *Result;
@@ -2225,7 +2239,16 @@ Node *Db::parseUnqualifiedName(NameState *State) {
    Result = parseUnnamedTypeName(State);
  else if (look() >= '1' && look() <= '9')
    Result = parseSourceName(State);
- else
+ else if (consumeIf("DC")) {
+   size_t BindingsBegin = Names.size();
+   do {
+     Node *Binding = parseSourceName(State);
+     if (Binding == nullptr)
+       return nullptr;
+     Names.push_back(Binding);
+   } while (!consumeIf('E'));
+   Result = make<StructuredBindingName>(popTrailingNodeArray(BindingsBegin));
+ } else
    Result = parseOperatorName(State);
  if (Result != nullptr)
    Result = parseAbiTags(Result);
@@ -2689,7 +2712,7 @@ Node *Db::parseNestedName(NameState *State) {
     }
 
     // Parse an <unqualified-name> thats actually a <ctor-dtor-name>.
-    if (look() == 'C' || look() == 'D') {
+    if (look() == 'C' || (look() == 'D' && look(1) != 'C')) {
       if (SoFar == nullptr)
         return nullptr;
       Node *CtorDtor = parseCtorDtorName(SoFar, State);
diff --git a/libcxxabi/test/test_demangle.pass.cpp b/libcxxabi/test/test_demangle.pass.cpp
index ef2821c..8e97a7f 100644
--- a/libcxxabi/test/test_demangle.pass.cpp
+++ b/libcxxabi/test/test_demangle.pass.cpp
@@ -29718,6 +29718,10 @@ const char* cases[][2] =
     {"_Z1fSsB1XS_", "f(std::string[abi:X], std::string[abi:X])"},
 
     {"___Z10blocksNRVOv_block_invoke", "invocation function for block in blocksNRVO()"},
+
+    // Structured bindings:
+    {"_ZDC2a12a2E", "'structured-binding'[a1, a2]"},
+    {"_ZN2NSDC1x1yEE", "NS::'structured-binding'[x, y]"},
 };
 
 const unsigned N = sizeof(cases) / sizeof(cases[0]);
@@ -29848,7 +29852,6 @@ void test_invalid_cases()
 
 const char *xfail_cases[] = {
     "_Z1fUa9enable_ifIXLi1EEEv", // enable_if attribute
-    "_ZDC2a12a2E", // decomposition decl
     "_ZW6FooBarE2f3v", // C++ modules TS
 
     // FIXME: Why does clang generate the "cp" expr?
-- 
2.7.4