[RFC 12/12] Wire up Randstruct; intercept and randomize

[Connor Kuehl via cfe-commits]

Co-authored-by: Cole Nixon <nixontcole at gmail.com>
Co-authored-by: Connor Kuehl <cipkuehl at gmail.com>
Co-authored-by: James Foster <jafosterja at gmail.com>
Co-authored-by: Jeff Takahashi <jeffrey.takahashi at gmail.com>
Co-authored-by: Jordan Cantrell <jordan.cantrell at mail.com>
Co-authored-by: Nikk Forbus <nicholas.forbus at gmail.com>
Co-authored-by: Tim Pugh <nwtpugh at gmail.com>
---
 clang/lib/AST/RecordLayoutBuilder.cpp | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index 99b7cbd0224..4bdf467db4d 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "clang/AST/RandstructSeed.h"
 #include "clang/AST/RecordLayout.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTDiagnostic.h"
@@ -15,6 +16,7 @@
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/Expr.h"
+#include "clang/AST/RecordFieldReorganizer.h"
 #include "clang/Basic/TargetInfo.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/Support/Format.h"
@@ -2984,6 +2986,24 @@ ASTContext::getASTRecordLayout(const RecordDecl *D) const {
 
   const ASTRecordLayout *NewEntry = nullptr;
 
+  bool ShouldBeRandomized = D->getAttr<RandomizeLayoutAttr>() != nullptr;
+  bool NotToBeRandomized = D->getAttr<NoRandomizeLayoutAttr>() != nullptr;
+  bool AutoSelectable = RandstructAutoSelect && Randstruct::isTriviallyRandomizable(D);
+
+  if (ShouldBeRandomized && NotToBeRandomized) {
+    getDiagnostics().Report(D->getLocation(), diag::warn_randomize_attr_conflict);
+  }
+
+  if (ShouldBeRandomized && D->isUnion()) {
+      getDiagnostics().Report(D->getLocation(), diag::warn_randomize_attr_union);
+      NotToBeRandomized = true;
+  }
+
+  if (!NotToBeRandomized && (ShouldBeRandomized || AutoSelectable)) {
+    Randstruct randstruct(RandstructSeed);
+    randstruct.reorganizeFields(*this,D);
+  }
+
   if (isMsLayout(*this)) {
     MicrosoftRecordLayoutBuilder Builder(*this);
     if (const auto *RD = dyn_cast<CXXRecordDecl>(D)) {
-- 
2.17.1