[Clang Interpreter] Initial patch for the constexpr interpreter

Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.

Reviewers: Bigcheese, jfb, rsmith

Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64146

llvm-svn: 371834

1 files changed, 46 insertions, 0 deletions

diff --git a/clang/lib/AST/Interp/Record.cpp b/clang/lib/AST/Interp/Record.cpp
new file mode 100644
index 00000000000..f440c470505
--- /dev/null
+++ b/clang/lib/AST/Interp/Record.cpp
@@ -0,0 +1,46 @@
+//===--- Record.cpp - struct and class metadata for the VM ------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "Record.h"
+
+using namespace clang;
+using namespace clang::interp;
+
+Record::Record(const RecordDecl *Decl, BaseList &&SrcBases,
+               FieldList &&SrcFields, VirtualBaseList &&SrcVirtualBases,
+               unsigned VirtualSize, unsigned BaseSize)
+    : Decl(Decl), Bases(std::move(SrcBases)), Fields(std::move(SrcFields)),
+      BaseSize(BaseSize), VirtualSize(VirtualSize) {
+  for (Base &V : SrcVirtualBases)
+    VirtualBases.push_back({ V.Decl, V.Offset + BaseSize, V.Desc, V.R });
+
+  for (Base &B : Bases)
+    BaseMap[B.Decl] = &B;
+  for (Field &F : Fields)
+    FieldMap[F.Decl] = &F;
+  for (Base &V : VirtualBases)
+    VirtualBaseMap[V.Decl] = &V;
+}
+
+const Record::Field *Record::getField(const FieldDecl *FD) const {
+  auto It = FieldMap.find(FD);
+  assert(It != FieldMap.end() && "Missing field");
+  return It->second;
+}
+
+const Record::Base *Record::getBase(const RecordDecl *FD) const {
+  auto It = BaseMap.find(FD);
+  assert(It != BaseMap.end() && "Missing base");
+  return It->second;
+}
+
+const Record::Base *Record::getVirtualBase(const RecordDecl *FD) const {
+  auto It = VirtualBaseMap.find(FD);
+  assert(It != VirtualBaseMap.end() && "Missing virtual base");
+  return It->second;
+}