[PATCH] D34233: [CFI] Add ability to explicitly link classes

[Enes Goktas via Phabricator via cfe-commits]

egoktas updated this revision to Diff 102641.
egoktas added a comment.

Remove the edits to CGExpr.cpp which accidentally got included in the diff.


https://reviews.llvm.org/D34233

Files:
  include/clang/Basic/SanitizerBlacklist.h
  lib/Basic/SanitizerBlacklist.cpp
  lib/CodeGen/CGVTables.cpp
  lib/CodeGen/CodeGenModule.cpp
  lib/CodeGen/CodeGenModule.h


Index: lib/CodeGen/CodeGenModule.h
===================================================================
--- lib/CodeGen/CodeGenModule.h
+++ lib/CodeGen/CodeGenModule.h
@@ -33,6 +33,7 @@
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/ValueHandle.h"
 #include "llvm/Transforms/Utils/SanitizerStats.h"
@@ -1204,6 +1205,8 @@
   /// Create and attach type metadata for the given vtable.
   void AddVTableTypeMetadata(llvm::GlobalVariable *VTable, CharUnits Offset,
                              const CXXRecordDecl *RD);
+  void AddVTableTypeMetadata(llvm::GlobalVariable *VTable, CharUnits Offset,
+                             llvm::Metadata *MD);
 
   /// \brief Get the declaration of std::terminate for the platform.
   llvm::Constant *getTerminateFn();
@@ -1213,6 +1216,9 @@
   llvm::Value *
   createOpenCLIntToSamplerConversion(const Expr *E, CodeGenFunction &CGF);
 
+  void GetSupplementalClasslinks(const CXXRecordDecl *BaseClass,
+                                 llvm::StringSet<> &SupplementalClasslinks);
+
   /// Get target specific null pointer.
   /// \param T is the LLVM type of the null pointer.
   /// \param QT is the clang QualType of the null pointer.
Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -4417,6 +4417,12 @@
                                           const CXXRecordDecl *RD) {
   llvm::Metadata *MD =
       CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
+  AddVTableTypeMetadata(VTable, Offset, MD);
+}
+
+void CodeGenModule::AddVTableTypeMetadata(llvm::GlobalVariable *VTable,
+                                          CharUnits Offset,
+                                          llvm::Metadata *MD) {
   VTable->addTypeMetadata(Offset.getQuantity(), MD);
 
   if (CodeGenOpts.SanitizeCfiCrossDso)
@@ -4475,3 +4481,16 @@
                                 "__translate_sampler_initializer"),
                                 {C});
 }
+
+void
+CodeGenModule::GetSupplementalClasslinks(const CXXRecordDecl *BaseClass,
+                                    llvm::StringSet<> &SupplementalClasslinks){
+  std::string mangledClassName;
+  llvm::raw_string_ostream Out(mangledClassName);
+  getCXXABI().getMangleContext().mangleTypeName(
+      QualType(BaseClass->getTypeForDecl(), 0), Out);
+  Out.flush();
+
+  getContext().getSanitizerBlacklist().getSupplementalClasslinks(
+                                     mangledClassName, SupplementalClasslinks);
+}
Index: lib/CodeGen/CGVTables.cpp
===================================================================
--- lib/CodeGen/CGVTables.cpp
+++ lib/CodeGen/CGVTables.cpp
@@ -986,7 +986,20 @@
     return E1.second < E2.second;
   });
 
-  for (auto BitsetEntry : BitsetEntries)
+  for (auto BitsetEntry : BitsetEntries){
+    const CXXRecordDecl *BaseClassOfVTable = BitsetEntry.first;
     AddVTableTypeMetadata(VTable, PointerWidth * BitsetEntry.second,
-                          BitsetEntry.first);
+                          BaseClassOfVTable);
+
+    // Check if user has defined supplemental class links for BaseClass.
+    llvm::StringSet<> SupplementalClasslinks;
+    GetSupplementalClasslinks(BaseClassOfVTable, SupplementalClasslinks);
+    for (auto I = SupplementalClasslinks.begin(),
+              E = SupplementalClasslinks.end(); I != E; I++){
+      llvm::Metadata* LinkedClassMD = llvm::MDString::get(getLLVMContext(),
+                                                                  I->getKey());
+      AddVTableTypeMetadata(VTable, PointerWidth * BitsetEntry.second,
+                            LinkedClassMD);
+    }
+  }
 }
Index: lib/Basic/SanitizerBlacklist.cpp
===================================================================
--- lib/Basic/SanitizerBlacklist.cpp
+++ lib/Basic/SanitizerBlacklist.cpp
@@ -44,3 +44,9 @@
          isBlacklistedFile(SM.getFilename(SM.getFileLoc(Loc)), Category);
 }
 
+void SanitizerBlacklist::getSupplementalClasslinks(StringRef mangledClassName,
+                             llvm::StringSet<> &SupplementalClasslinks) const {
+  SCL->getEntriesInSection("classlink", SupplementalClasslinks,
+                           mangledClassName);
+}
+
Index: include/clang/Basic/SanitizerBlacklist.h
===================================================================
--- include/clang/Basic/SanitizerBlacklist.h
+++ include/clang/Basic/SanitizerBlacklist.h
@@ -18,6 +18,7 @@
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/SourceManager.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSet.h"
 #include "llvm/Support/SpecialCaseList.h"
 #include <memory>
 
@@ -39,6 +40,8 @@
                          StringRef Category = StringRef()) const;
   bool isBlacklistedLocation(SourceLocation Loc,
                              StringRef Category = StringRef()) const;
+  void getSupplementalClasslinks(StringRef mangledClassName,
+                              llvm::StringSet<> &SupplementalClasslinks) const;
 };
 
 }  // end namespace clang

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