[PATCH] D136012: [clang][Interp] Fix record members of reference type

[Timm Bäder via Phabricator via cfe-commits]

tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
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  When assigning to them, we can't classify the expression type, because
  that doesn't contain the right information.
  
  And when reading from them, we need to do the extra deref, just like we
  do when reading from a DeclRefExpr.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D136012

Files:
  clang/lib/AST/Interp/ByteCodeExprGen.cpp
  clang/lib/AST/Interp/ByteCodeStmtGen.cpp
  clang/test/AST/Interp/references.cpp


Index: clang/test/AST/Interp/references.cpp
===================================================================
--- clang/test/AST/Interp/references.cpp
+++ clang/test/AST/Interp/references.cpp
@@ -88,3 +88,29 @@
   return j;
 }
 static_assert(RefToMemberExpr() == 11, "");
+
+struct Ref {
+  int &a;
+};
+
+constexpr int RecordWithRef() {
+  int m = 100;
+  Ref r{m};
+  m = 200;
+  return r.a;
+}
+static_assert(RecordWithRef() == 200, "");
+
+
+struct Ref2 {
+  int &a;
+  constexpr Ref2(int &a) : a(a) {}
+};
+
+constexpr int RecordWithRef2() {
+  int m = 100;
+  Ref2 r(m);
+  m = 200;
+  return r.a;
+}
+static_assert(RecordWithRef2() == 200, "");
Index: clang/lib/AST/Interp/ByteCodeStmtGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeStmtGen.cpp
+++ clang/lib/AST/Interp/ByteCodeStmtGen.cpp
@@ -104,7 +104,7 @@
       if (const FieldDecl *Member = Init->getMember()) {
         const Record::Field *F = R->getField(Member);
 
-        if (Optional<PrimType> T = this->classify(InitExpr->getType())) {
+        if (Optional<PrimType> T = this->classify(InitExpr)) {
           if (!this->emitThis(InitExpr))
             return false;
 
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -397,7 +397,11 @@
     const Record *R = getRecord(RD);
     const Record::Field *F = R->getField(FD);
     // Leave a pointer to the field on the stack.
-    return this->emitGetPtrField(F->Offset, E);
+    if (!this->emitGetPtrField(F->Offset, E))
+      return false;
+    if (F->Decl->getType()->isReferenceType())
+      return this->emitLoadPopPtr(E);
+    return true;
   }
 
   return false;
@@ -871,7 +875,7 @@
       if (!this->emitDupPtr(Initializer))
         return false;
 
-      if (Optional<PrimType> T = classify(Init->getType())) {
+      if (Optional<PrimType> T = classify(Init)) {
         if (!this->visit(Init))
           return false;
 


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