Abstract out the emission of vtables, add basic support for vtable emission when using -cxx-abi microsoft
Reviewed at http://llvm-reviews.chandlerc.com/D1532
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191523 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MicrosoftCXXABI.cpp b/lib/CodeGen/MicrosoftCXXABI.cpp
index e5d7c49..cfdbaa2 100644
--- a/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -21,6 +21,7 @@
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/VTableBuilder.h"
+#include "llvm/ADT/StringSet.h"
using namespace clang;
using namespace CodeGen;
@@ -150,6 +151,20 @@
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd);
+ void emitVTableDefinitions(CodeGenVTables &CGVT, const CXXRecordDecl *RD);
+
+ llvm::Value *getVTableAddressPointInStructor(
+ CodeGenFunction &CGF, const CXXRecordDecl *VTableClass,
+ BaseSubobject Base, const CXXRecordDecl *NearestVBase,
+ bool &NeedsVirtualOffset);
+
+ llvm::Constant *
+ getVTableAddressPointForConstExpr(BaseSubobject Base,
+ const CXXRecordDecl *VTableClass);
+
+ llvm::GlobalVariable *getAddrOfVTable(const CXXRecordDecl *RD,
+ CharUnits VPtrOffset);
+
llvm::Value *getVirtualFunctionPointer(CodeGenFunction &CGF, GlobalDecl GD,
llvm::Value *This, llvm::Type *Ty);
@@ -158,8 +173,7 @@
CXXDtorType DtorType, SourceLocation CallLoc,
llvm::Value *This);
- void EmitVirtualInheritanceTables(llvm::GlobalVariable::LinkageTypes Linkage,
- const CXXRecordDecl *RD);
+ void emitVirtualInheritanceTables(const CXXRecordDecl *RD);
void EmitGuardedInit(CodeGenFunction &CGF, const VarDecl &D,
llvm::GlobalVariable *DeclPtr,
@@ -303,7 +317,16 @@
const MemberPointerType *MPT);
private:
- /// VBTables - All the vbtables which have been referenced.
+ typedef std::pair<const CXXRecordDecl *, CharUnits> VFTableIdTy;
+ typedef llvm::DenseMap<VFTableIdTy, llvm::GlobalVariable *> VFTablesMapTy;
+ /// \brief All the vftables that have been referenced.
+ VFTablesMapTy VFTablesMap;
+
+ /// \brief This set holds the record decls we've deferred vtable emission for.
+ llvm::SmallPtrSet<const CXXRecordDecl *, 4> DeferredVFTables;
+
+
+ /// \brief All the vbtables which have been referenced.
llvm::DenseMap<const CXXRecordDecl *, VBTableVector> VBTablesMap;
/// Info on the global variable used to guard initialization of static locals.
@@ -616,6 +639,116 @@
ImplicitParam, ImplicitParamTy, ArgBeg, ArgEnd);
}
+void MicrosoftCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
+ const CXXRecordDecl *RD) {
+ MicrosoftVFTableContext &VFTContext = CGM.getVFTableContext();
+ MicrosoftVFTableContext::VFPtrListTy VFPtrs = VFTContext.getVFPtrOffsets(RD);
+ llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
+
+ for (MicrosoftVFTableContext::VFPtrListTy::iterator I = VFPtrs.begin(),
+ E = VFPtrs.end(); I != E; ++I) {
+ llvm::GlobalVariable *VTable = getAddrOfVTable(RD, I->VFPtrFullOffset);
+ if (VTable->hasInitializer())
+ continue;
+
+ const VTableLayout &VTLayout =
+ VFTContext.getVFTableLayout(RD, I->VFPtrFullOffset);
+ llvm::Constant *Init = CGVT.CreateVTableInitializer(
+ RD, VTLayout.vtable_component_begin(),
+ VTLayout.getNumVTableComponents(), VTLayout.vtable_thunk_begin(),
+ VTLayout.getNumVTableThunks());
+ VTable->setInitializer(Init);
+
+ VTable->setLinkage(Linkage);
+ CGM.setTypeVisibility(VTable, RD, CodeGenModule::TVK_ForVTable);
+ }
+}
+
+llvm::Value *MicrosoftCXXABI::getVTableAddressPointInStructor(
+ CodeGenFunction &CGF, const CXXRecordDecl *VTableClass, BaseSubobject Base,
+ const CXXRecordDecl *NearestVBase, bool &NeedsVirtualOffset) {
+ NeedsVirtualOffset = (NearestVBase != 0);
+
+ llvm::Value *VTableAddressPoint =
+ getAddrOfVTable(VTableClass, Base.getBaseOffset());
+ if (!VTableAddressPoint) {
+ assert(Base.getBase()->getNumVBases() &&
+ !CGM.getContext().getASTRecordLayout(Base.getBase()).hasOwnVFPtr());
+ }
+ return VTableAddressPoint;
+}
+
+static void mangleVFTableName(CodeGenModule &CGM, const CXXRecordDecl *RD,
+ const VFPtrInfo &VFPtr, SmallString<256> &Name) {
+ llvm::raw_svector_ostream Out(Name);
+ CGM.getCXXABI().getMangleContext().mangleCXXVFTable(
+ RD, VFPtr.PathToMangle, Out);
+}
+
+llvm::Constant *MicrosoftCXXABI::getVTableAddressPointForConstExpr(
+ BaseSubobject Base, const CXXRecordDecl *VTableClass) {
+ llvm::Constant *VTable = getAddrOfVTable(VTableClass, Base.getBaseOffset());
+ assert(VTable && "Couldn't find a vftable for the given base?");
+ return VTable;
+}
+
+llvm::GlobalVariable *MicrosoftCXXABI::getAddrOfVTable(const CXXRecordDecl *RD,
+ CharUnits VPtrOffset) {
+ // getAddrOfVTable may return 0 if asked to get an address of a vtable which
+ // shouldn't be used in the given record type. We want to cache this result in
+ // VFTablesMap, thus a simple zero check is not sufficient.
+ VFTableIdTy ID(RD, VPtrOffset);
+ VFTablesMapTy::iterator I;
+ bool Inserted;
+ llvm::tie(I, Inserted) = VFTablesMap.insert(
+ std::make_pair(ID, static_cast<llvm::GlobalVariable *>(0)));
+ if (!Inserted)
+ return I->second;
+
+ llvm::GlobalVariable *&VTable = I->second;
+
+ MicrosoftVFTableContext &VFTContext = CGM.getVFTableContext();
+ const MicrosoftVFTableContext::VFPtrListTy &VFPtrs =
+ VFTContext.getVFPtrOffsets(RD);
+
+ if (DeferredVFTables.insert(RD)) {
+ // We haven't processed this record type before.
+ // Queue up this v-table for possible deferred emission.
+ CGM.addDeferredVTable(RD);
+
+#ifndef NDEBUG
+ // Create all the vftables at once in order to make sure each vftable has
+ // a unique mangled name.
+ llvm::StringSet<> ObservedMangledNames;
+ for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
+ SmallString<256> Name;
+ mangleVFTableName(CGM, RD, VFPtrs[J], Name);
+ if (!ObservedMangledNames.insert(Name.str()))
+ llvm_unreachable("Already saw this mangling before?");
+ }
+#endif
+ }
+
+ for (size_t J = 0, F = VFPtrs.size(); J != F; ++J) {
+ if (VFPtrs[J].VFPtrFullOffset != VPtrOffset)
+ continue;
+
+ llvm::ArrayType *ArrayType = llvm::ArrayType::get(
+ CGM.Int8PtrTy,
+ VFTContext.getVFTableLayout(RD, VFPtrs[J].VFPtrFullOffset)
+ .getNumVTableComponents());
+
+ SmallString<256> Name;
+ mangleVFTableName(CGM, RD, VFPtrs[J], Name);
+ VTable = CGM.CreateOrReplaceCXXRuntimeVariable(
+ Name.str(), ArrayType, llvm::GlobalValue::ExternalLinkage);
+ VTable->setUnnamedAddr(true);
+ break;
+ }
+
+ return VTable;
+}
+
llvm::Value *MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
GlobalDecl GD,
llvm::Value *This,
@@ -674,9 +807,10 @@
return VBTables;
}
-void MicrosoftCXXABI::EmitVirtualInheritanceTables(
- llvm::GlobalVariable::LinkageTypes Linkage, const CXXRecordDecl *RD) {
+void MicrosoftCXXABI::emitVirtualInheritanceTables(const CXXRecordDecl *RD) {
const VBTableVector &VBTables = EnumerateVBTables(RD);
+ llvm::GlobalVariable::LinkageTypes Linkage = CGM.getVTableLinkage(RD);
+
for (VBTableVector::const_iterator I = VBTables.begin(), E = VBTables.end();
I != E; ++I) {
I->EmitVBTableDefinition(CGM, RD, Linkage);