[clang] [clang][bytecode] Add opaque pointers to support type-only pointers (PR #213017)

[Timm Baeder via cfe-commits]

Timm =?utf-8?q?Bäder?= <tbaeder at redhat.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/213017 at github.com>


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@@ -0,0 +1,508 @@
+//===------------- InterpBuiltinObjectSize.cpp ------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+// Implementation of the frontend part of the __builtin_object_size and
+// __builtin_dynamic_object_size builtins.
+
+#include "InterpHelpers.h"
+#include "Pointer.h"
+#include "Record.h"
+#include "clang/AST/RecordLayout.h"
+
+using namespace clang;
+using namespace clang::interp;
+
+enum : uint8_t {
+  Regular = 1 << 0,
+  IgnoreBaseCasts = 1 << 1,
+  SurroundingArray = 1 << 2,
+};
+
+// Helper to check if a RecordDecl can be passed to
+// ASTContext::getRecordLayout().
+static bool validRecordDecl(const RecordDecl *D) {
+  D = D->getDefinition();
+  return D && !D->isInvalidDecl() && D->isCompleteDefinition();
+}
+
+// Same but for types.
+static bool validType(QualType T) {
+  if (const RecordDecl *RD = T->getAsRecordDecl())
+    return validRecordDecl(RD);
+  return true;
+}
+
+static QualType computeFieldType(const ASTContext &ASTCtx,
+                                 const OpaquePointer &OP,
+                                 unsigned TypeModifier = 0) {
+  QualType CurType = OP.getObjectType();
+
+  unsigned Drop = 0;
+  if (TypeModifier & IgnoreBaseCasts && OP.PathLength != 0 &&
+      OP.path().back().Kind == PointerPathEntry::Base)
+    Drop = 1;
+
+  if (TypeModifier & SurroundingArray && OP.PathLength != 0 &&
+      OP.path().back().Kind == PointerPathEntry::Array)
+    Drop = 1;
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tbaederr wrote:

Yes

https://github.com/llvm/llvm-project/pull/213017