[PATCH] D150661: [clang][Interp] Allow evaluating standalone composite expressions

[Timm Bäder via Phabricator via cfe-commits]

tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
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  We reach visitExpr() when evaluating standalone expressions. However,
  the RetValue() code path was unused before, because we never reach it,
  even with structs or arrays.
  
  RetValue expects a pointer on the stack it can take apart to return an
  APValue, so provide it with one.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D150661

Files:
  clang/lib/AST/Interp/ByteCodeExprGen.cpp
  clang/test/AST/Interp/complex.cpp


Index: clang/test/AST/Interp/complex.cpp
===================================================================
--- clang/test/AST/Interp/complex.cpp
+++ clang/test/AST/Interp/complex.cpp
@@ -38,6 +38,10 @@
 static_assert(__imag(I2) == 0, "");
 
 
+// Standalone complex expressions.
+static_assert(__real((_Complex float){1.0, 3.0}) == 1.0, "");
+
+
 #if 0
 /// FIXME: This should work in the new interpreter.
 constexpr _Complex double D2 = {12};
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -1887,9 +1887,16 @@
   // Expressions with a composite return type.
   // For us, that means everything we don't
   // have a PrimType for.
-  if (!visit(E))
-    return false;
-  return this->emitRetValue(E);
+  if (std::optional<unsigned> LocalOffset = this->allocateLocal(E)) {
+    if (!this->visitLocalInitializer(E, *LocalOffset))
+      return false;
+
+    if (!this->emitGetPtrLocal(*LocalOffset, E))
+      return false;
+    return this->emitRetValue(E);
+  }
+
+  return false;
 }
 
 /// Toplevel visitDecl().


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