diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -3509,6 +3509,35 @@
 
     source_filename = "/path/to/source.c"
 
+.. _structured_data:
+
+Structured Data
+---------------
+
+Dictionaries of key-value pairs are used in some cases to represent data in an
+easily extendable, human-readable manner.
+
+The labels used in key-value pairs are identifiers followed immediately by a
+colon (':'), like the label of a named basic block.
+
+:Syntax:
+
+::
+
+    sdata       ::= '{' (sdata_field ',')* sdata_field? '}'
+    sdata_field ::= label sdata_value
+    sdata_value ::= 'type' type
+                ::= 'iN' integer
+                ::= 'i1' 'true' | 'i1' 'false'
+
+:Examples:
+
+::
+
+    {}
+    { layout: type float, }
+    { foo: i1 true, bar: i32 10 }
+
 .. _typesystem:
 
 Type System
diff --git a/llvm/include/llvm/AsmParser/LLParser.h b/llvm/include/llvm/AsmParser/LLParser.h
--- a/llvm/include/llvm/AsmParser/LLParser.h
+++ b/llvm/include/llvm/AsmParser/LLParser.h
@@ -20,6 +20,7 @@
 #include "llvm/IR/FMF.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/ModuleSummaryIndex.h"
+#include "llvm/IR/StructuredData.h"
 #include <map>
 #include <optional>
 
@@ -558,6 +559,10 @@
     bool parseGlobalObjectMetadataAttachment(GlobalObject &GO);
     bool parseOptionalFunctionMetadata(Function &F);
 
+    bool parseStructuredData(
+        function_ref<bool(LocTy, StringRef, LocTy, sdata::Value)>
+            ParseField);
+
     template <class FieldTy>
     bool parseMDField(LocTy Loc, StringRef Name, FieldTy &Result);
     template <class FieldTy> bool parseMDField(StringRef Name, FieldTy &Result);
diff --git a/llvm/include/llvm/IR/StructuredData.h b/llvm/include/llvm/IR/StructuredData.h
new file mode 100644
--- /dev/null
+++ b/llvm/include/llvm/IR/StructuredData.h
@@ -0,0 +1,83 @@
+//===- llvm/IR/StructuredData.h ---------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides structured data objects that are used as an intermediate
+// abstraction for (de)serializing extensible IR objects.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_IR_STRUCTUREDDATA_H
+#define LLVM_IR_STRUCTUREDDATA_H
+
+#include "llvm/ADT/APInt.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
+
+namespace llvm {
+
+class Type;
+
+namespace sdata {
+
+/// A value of structured data.
+class Value {
+private:
+  using Storage = std::variant<std::monostate, APInt, Type *>;
+
+  Storage S;
+
+public:
+  Value() = default;
+  explicit Value(Type *T) : S(T) {}
+  explicit Value(bool B) : S(APInt(1, B ? 1 : 0)) {}
+  explicit Value(APInt I) : S(I) {}
+
+  Value &operator=(Type *T) {
+    assert(T);
+    S = T;
+    return *this;
+  }
+  Value &operator=(bool B) {
+    S = APInt(1, B ? 1 : 0);
+    return *this;
+  }
+  Value &operator=(APInt I) {
+    S = I;
+    return *this;
+  }
+
+  bool isAPInt() const { return std::holds_alternative<APInt>(S); }
+  bool isBool() const {
+    return isAPInt() && std::get<APInt>(S).getBitWidth() == 1;
+  }
+  bool isType() const { return std::holds_alternative<Type *>(S); }
+
+  const APInt &getAPInt() const {
+    assert(isAPInt());
+    return std::get<APInt>(S);
+  }
+  bool getBool() const {
+    assert(isBool());
+    return std::get<APInt>(S).getZExtValue();
+  }
+  Type *getType() const {
+    assert(isType());
+    return std::get<Type *>(S);
+  }
+};
+
+// Convenience function to create an Error object when an error is encountered
+// while deserializing structured data.
+Error makeDeserializeError(const Twine &Msg);
+
+} // end namespace sdata
+
+} // end namespace llvm
+
+#endif
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -4190,6 +4190,82 @@
   return false;
 }
 
+/// parseStructuredData
+///   ::= '{' (key value (',' key value))? ','? '}'
+///
+/// value ::= 'type' type
+///       ::= 'i1' 'true' | 'i1' 'false'
+///       ::= 'iN' integer
+bool LLParser::parseStructuredData(
+    function_ref<bool(LocTy, StringRef, LocTy, sdata::Value)> ParseField) {
+  if (parseToken(lltok::lbrace, "expected '{' here"))
+    return true;
+
+  while (Lex.getKind() != lltok::rbrace) {
+    if (Lex.getKind() != lltok::LabelStr)
+      return tokError("expected '}' or field label here");
+
+    LocTy KeyLoc = Lex.getLoc();
+    std::string Key = Lex.getStrVal();
+    Lex.Lex();
+
+    LocTy ValueLoc = Lex.getLoc();
+    sdata::Value V;
+    switch (Lex.getKind()) {
+    case lltok::kw_type: {
+      Lex.Lex(); // eat 'type'
+
+      Type *T;
+      if (parseType(T, /*AllowVoid=*/true))
+        return true;
+
+      V = sdata::Value(T);
+      break;
+    }
+    case lltok::Type: {
+      Type *Ty = Lex.getTyVal();
+      if (auto *IntTy = dyn_cast<IntegerType>(Ty)) {
+        Lex.Lex();
+
+        switch (Lex.getKind()) {
+        case lltok::APSInt:
+          V = sdata::Value(Lex.getAPSIntVal().extOrTrunc(IntTy->getBitWidth()));
+          Lex.Lex();
+          break;
+        case lltok::kw_true:
+        case lltok::kw_false:
+          if (IntTy->getBitWidth() != 1)
+            return tokError("true/false can only be used with i1");
+          V = sdata::Value(Lex.getKind() == lltok::kw_true);
+          Lex.Lex();
+          break;
+        default:
+          return tokError("expected an integer value");
+        }
+
+        break;
+      }
+
+      return tokError("only integer types are supported in structured data");
+    }
+
+    default:
+      return tokError("expected structured data value");
+    }
+
+    if (ParseField(KeyLoc, Key, ValueLoc, V))
+      return true;
+
+    if (Lex.getKind() == lltok::rbrace)
+      break;
+    if (parseToken(lltok::comma, "expected ',' or '}' here"))
+      return true;
+  }
+
+  Lex.Lex(); // eat the '}'
+  return false;
+}
+
 bool LLParser::parseMDTuple(MDNode *&MD, bool IsDistinct) {
   SmallVector<Metadata *, 16> Elts;
   if (parseMDNodeVector(Elts))
diff --git a/llvm/lib/IR/AsmWriter.cpp b/llvm/lib/IR/AsmWriter.cpp
--- a/llvm/lib/IR/AsmWriter.cpp
+++ b/llvm/lib/IR/AsmWriter.cpp
@@ -58,6 +58,7 @@
 #include "llvm/IR/ModuleSlotTracker.h"
 #include "llvm/IR/ModuleSummaryIndex.h"
 #include "llvm/IR/Operator.h"
+#include "llvm/IR/StructuredData.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/TypeFinder.h"
 #include "llvm/IR/TypedPointerType.h"
@@ -1323,6 +1324,31 @@
 // AsmWriter Implementation
 //===----------------------------------------------------------------------===//
 
+static void printStructuredData(
+    raw_ostream &Out, ArrayRef<std::pair<StringRef, sdata::Value>> Fields,
+    AsmWriterContext &Ctx) {
+  Out << "{\n";
+  for (const auto &Field : Fields) {
+    Out << "  " << Field.first << ": ";
+    if (Field.second.isBool()) {
+      if (Field.second.getBool())
+        Out << "i1 true";
+      else
+        Out << "i1 false";
+    } else if (Field.second.isAPInt()) {
+      const APInt &I = Field.second.getAPInt();
+      Out << 'i' << I.getBitWidth() << ' ' << I;
+    } else if (Field.second.isType()) {
+      Out << "type ";
+      Ctx.TypePrinter->print(Field.second.getType(), Out);
+    } else {
+      llvm_unreachable("unhandled sdata::Value type");
+    }
+    Out << ",\n";
+  }
+  Out << '}';
+}
+
 static void WriteAsOperandInternal(raw_ostream &Out, const Value *V,
                                    AsmWriterContext &WriterCtx);
 
diff --git a/llvm/lib/IR/CMakeLists.txt b/llvm/lib/IR/CMakeLists.txt
--- a/llvm/lib/IR/CMakeLists.txt
+++ b/llvm/lib/IR/CMakeLists.txt
@@ -57,6 +57,7 @@
   ReplaceConstant.cpp
   Statepoint.cpp
   StructuralHash.cpp
+  StructuredData.cpp
   Type.cpp
   TypedPointerType.cpp
   TypeFinder.cpp
diff --git a/llvm/lib/IR/StructuredData.cpp b/llvm/lib/IR/StructuredData.cpp
new file mode 100644
--- /dev/null
+++ b/llvm/lib/IR/StructuredData.cpp
@@ -0,0 +1,43 @@
+//===- StructuredData.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/StructuredData.h"
+
+using namespace llvm;
+using namespace sdata;
+
+namespace {
+
+enum class DeserializeErrorCode : int {
+  Generic = 1,
+};
+
+class DeserializeErrorCategory : public std::error_category {
+public:
+  const char *name() const noexcept override {
+    return "Structure Data Deserialize Error";
+  }
+
+  std::string message(int condition) const override {
+    return "Error while deserializing structured data";
+  }
+
+  static DeserializeErrorCategory &get() {
+    static DeserializeErrorCategory TheCategory;
+    return TheCategory;
+  }
+};
+
+} // anonymous namespace
+
+Error llvm::sdata::makeDeserializeError(const Twine &Msg) {
+  return createStringError(
+      std::error_code(static_cast<int>(DeserializeErrorCode::Generic),
+                      DeserializeErrorCategory::get()),
+      Msg);
+}