Merge branch 'master' of ssh://bitbucket.org/czan/honours

1 files changed, 192 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGVTT.cpp b/clang/lib/CodeGen/CGVTT.cpp
new file mode 100644
index 0000000..98be872
--- /dev/null
+++ b/clang/lib/CodeGen/CGVTT.cpp
@@ -0,0 +1,192 @@
+//===--- CGVTT.cpp - Emit LLVM Code for C++ VTTs --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This contains code dealing with C++ code generation of VTTs (vtable tables).
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenModule.h"
+#include "CGCXXABI.h"
+#include "clang/AST/RecordLayout.h"
+#include "clang/AST/VTTBuilder.h"
+using namespace clang;
+using namespace CodeGen;
+
+static llvm::Constant *
+GetAddrOfVTTVTable(CodeGenVTables &CGVT, const CXXRecordDecl *MostDerivedClass,
+                   const VTTVTable &VTable,
+                   llvm::GlobalVariable::LinkageTypes Linkage,
+                   llvm::DenseMap<BaseSubobject, uint64_t> &AddressPoints) {
+  if (VTable.getBase() == MostDerivedClass) {
+    assert(VTable.getBaseOffset().isZero() &&
+           "Most derived class vtable must have a zero offset!");
+    // This is a regular vtable.
+    return CGVT.GetAddrOfVTable(MostDerivedClass);
+  }
+  
+  return CGVT.GenerateConstructionVTable(MostDerivedClass, 
+                                         VTable.getBaseSubobject(),
+                                         VTable.isVirtual(),
+                                         Linkage,
+                                         AddressPoints);
+}
+
+void
+CodeGenVTables::EmitVTTDefinition(llvm::GlobalVariable *VTT,
+                                  llvm::GlobalVariable::LinkageTypes Linkage,
+                                  const CXXRecordDecl *RD) {
+  VTTBuilder Builder(CGM.getContext(), RD, /*GenerateDefinition=*/true);
+
+  llvm::Type *Int8PtrTy = CGM.Int8PtrTy, *Int64Ty = CGM.Int64Ty;
+  llvm::ArrayType *ArrayType = 
+    llvm::ArrayType::get(Int8PtrTy, Builder.getVTTComponents().size());
+  
+  SmallVector<llvm::Constant *, 8> VTables;
+  SmallVector<VTableAddressPointsMapTy, 8> VTableAddressPoints;
+  for (const VTTVTable *i = Builder.getVTTVTables().begin(),
+                       *e = Builder.getVTTVTables().end(); i != e; ++i) {
+    VTableAddressPoints.push_back(VTableAddressPointsMapTy());
+    VTables.push_back(GetAddrOfVTTVTable(*this, RD, *i, Linkage,
+                                         VTableAddressPoints.back()));
+  }
+
+  SmallVector<llvm::Constant *, 8> VTTComponents;
+  for (const VTTComponent *i = Builder.getVTTComponents().begin(),
+                          *e = Builder.getVTTComponents().end(); i != e; ++i) {
+    const VTTVTable &VTTVT = Builder.getVTTVTables()[i->VTableIndex];
+    llvm::Constant *VTable = VTables[i->VTableIndex];
+    uint64_t AddressPoint;
+    if (VTTVT.getBase() == RD) {
+      // Just get the address point for the regular vtable.
+      AddressPoint = VTContext.getVTableLayout(RD)
+                              .getAddressPoint(i->VTableBase);
+      assert(AddressPoint != 0 && "Did not find vtable address point!");
+    } else {
+      AddressPoint = VTableAddressPoints[i->VTableIndex].lookup(i->VTableBase);
+      assert(AddressPoint != 0 && "Did not find ctor vtable address point!");
+    }
+
+     llvm::Value *Idxs[] = {
+       llvm::ConstantInt::get(Int64Ty, 0),
+       llvm::ConstantInt::get(Int64Ty, AddressPoint)
+     };
+
+     llvm::Constant *Init = 
+       llvm::ConstantExpr::getInBoundsGetElementPtr(VTable, Idxs);
+
+     Init = llvm::ConstantExpr::getBitCast(Init, Int8PtrTy);
+
+     VTTComponents.push_back(Init);
+  }
+
+  llvm::Constant *Init = llvm::ConstantArray::get(ArrayType, VTTComponents);
+
+  VTT->setInitializer(Init);
+
+  // Set the correct linkage.
+  VTT->setLinkage(Linkage);
+
+  // Set the right visibility.
+  CGM.setTypeVisibility(VTT, RD, CodeGenModule::TVK_ForVTT);
+}
+
+llvm::GlobalVariable *CodeGenVTables::GetAddrOfVTT(const CXXRecordDecl *RD) {
+  assert(RD->getNumVBases() && "Only classes with virtual bases need a VTT");
+
+  SmallString<256> OutName;
+  llvm::raw_svector_ostream Out(OutName);
+  CGM.getCXXABI().getMangleContext().mangleCXXVTT(RD, Out);
+  Out.flush();
+  StringRef Name = OutName.str();
+
+  // This will also defer the definition of the VTT.
+  (void) GetAddrOfVTable(RD);
+
+  VTTBuilder Builder(CGM.getContext(), RD, /*GenerateDefinition=*/false);
+
+  llvm::ArrayType *ArrayType = 
+    llvm::ArrayType::get(CGM.Int8PtrTy, Builder.getVTTComponents().size());
+
+  llvm::GlobalVariable *GV =
+    CGM.CreateOrReplaceCXXRuntimeVariable(Name, ArrayType, 
+                                          llvm::GlobalValue::ExternalLinkage);
+  GV->setUnnamedAddr(true);
+  return GV;
+}
+
+bool CodeGenVTables::needsVTTParameter(GlobalDecl GD) {
+  const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
+  
+  // We don't have any virtual bases, just return early.
+  if (!MD->getParent()->getNumVBases())
+    return false;
+  
+  // Check if we have a base constructor.
+  if (isa<CXXConstructorDecl>(MD) && GD.getCtorType() == Ctor_Base)
+    return true;
+
+  // Check if we have a base destructor.
+  if (isa<CXXDestructorDecl>(MD) && GD.getDtorType() == Dtor_Base)
+    return true;
+  
+  return false;
+}
+
+uint64_t CodeGenVTables::getSubVTTIndex(const CXXRecordDecl *RD, 
+                                        BaseSubobject Base) {
+  BaseSubobjectPairTy ClassSubobjectPair(RD, Base);
+
+  SubVTTIndiciesMapTy::iterator I = SubVTTIndicies.find(ClassSubobjectPair);
+  if (I != SubVTTIndicies.end())
+    return I->second;
+  
+  VTTBuilder Builder(CGM.getContext(), RD, /*GenerateDefinition=*/false);
+
+  for (llvm::DenseMap<BaseSubobject, uint64_t>::const_iterator I =
+       Builder.getSubVTTIndicies().begin(), 
+       E = Builder.getSubVTTIndicies().end(); I != E; ++I) {
+    // Insert all indices.
+    BaseSubobjectPairTy ClassSubobjectPair(RD, I->first);
+    
+    SubVTTIndicies.insert(std::make_pair(ClassSubobjectPair, I->second));
+  }
+    
+  I = SubVTTIndicies.find(ClassSubobjectPair);
+  assert(I != SubVTTIndicies.end() && "Did not find index!");
+  
+  return I->second;
+}
+
+uint64_t 
+CodeGenVTables::getSecondaryVirtualPointerIndex(const CXXRecordDecl *RD,
+                                                BaseSubobject Base) {
+  SecondaryVirtualPointerIndicesMapTy::iterator I =
+    SecondaryVirtualPointerIndices.find(std::make_pair(RD, Base));
+
+  if (I != SecondaryVirtualPointerIndices.end())
+    return I->second;
+
+  VTTBuilder Builder(CGM.getContext(), RD, /*GenerateDefinition=*/false);
+
+  // Insert all secondary vpointer indices.
+  for (llvm::DenseMap<BaseSubobject, uint64_t>::const_iterator I = 
+       Builder.getSecondaryVirtualPointerIndices().begin(),
+       E = Builder.getSecondaryVirtualPointerIndices().end(); I != E; ++I) {
+    std::pair<const CXXRecordDecl *, BaseSubobject> Pair =
+      std::make_pair(RD, I->first);
+    
+    SecondaryVirtualPointerIndices.insert(std::make_pair(Pair, I->second));
+  }
+
+  I = SecondaryVirtualPointerIndices.find(std::make_pair(RD, Base));
+  assert(I != SecondaryVirtualPointerIndices.end() && "Did not find index!");
+  
+  return I->second;
+}
+