[PATCH] D134629: [clang][Interp] Fix Pointer::toAPValue() LValuePath order

[Timm Bäder via Phabricator via cfe-commits]

tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
Herald added a project: All.
tbaeder requested review of this revision.
Herald added a project: clang.
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See the comment I added for an explanation. This fixes the commented-out testcases I added in https://reviews.llvm.org/D134523.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D134629

Files:
  clang/lib/AST/Interp/Pointer.cpp
  clang/test/AST/Interp/records.cpp


Index: clang/test/AST/Interp/records.cpp
===================================================================
--- clang/test/AST/Interp/records.cpp
+++ clang/test/AST/Interp/records.cpp
@@ -153,11 +153,7 @@
 constexpr FourBoolPairs LT;
 // Copy ctor
 constexpr FourBoolPairs LT2 = LT;
-// FIXME: The copy constructor call above
-//   works, but APValue we generate for it is
-//   not sufficiently correct, so the lvalue-to-rvalue
-//   conversion in ExprConstant.c runs into an assertion.
-//static_assert(LT2.v[0].first == false, "");
-//static_assert(LT2.v[0].second == false, "");
-//static_assert(LT2.v[2].first == true, "");
-//static_assert(LT2.v[2].second == false, "");
+static_assert(LT2.v[0].first == false, "");
+static_assert(LT2.v[0].second == false, "");
+static_assert(LT2.v[2].first == true, "");
+static_assert(LT2.v[2].second == false, "");
Index: clang/lib/AST/Interp/Pointer.cpp
===================================================================
--- clang/lib/AST/Interp/Pointer.cpp
+++ clang/lib/AST/Interp/Pointer.cpp
@@ -148,7 +148,16 @@
     }
   }
 
-  return APValue(Base, Offset, Path, IsOnePastEnd, IsNullPtr);
+  // We assemble the LValuePath starting from the innermost pointer to the
+  // outermost one. SO in a.b.c, the first element in Path will refer to
+  // the field 'c', while later code expects it to refer to 'a'.
+  // Just invert the order of the elements.
+  decltype(Path) RealPath;
+  RealPath.resize(Path.size());
+  for (unsigned I = 0, N = Path.size(); I != N; ++I)
+    RealPath[N - 1 - I] = Path[I];
+
+  return APValue(Base, Offset, RealPath, IsOnePastEnd, IsNullPtr);
 }
 
 bool Pointer::isInitialized() const {


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