forked from OSchip/llvm-project
1003 lines
33 KiB
C++
1003 lines
33 KiB
C++
//=== ASTRecordLayoutBuilder.cpp - Helper class for building record layouts ==//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "RecordLayoutBuilder.h"
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#include "clang/AST/Attr.h"
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#include "clang/AST/Decl.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/AST/DeclObjC.h"
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#include "clang/AST/Expr.h"
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#include "clang/Basic/TargetInfo.h"
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#include "llvm/Support/Format.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/Support/MathExtras.h"
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using namespace clang;
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ASTRecordLayoutBuilder::ASTRecordLayoutBuilder(ASTContext &Context)
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: Context(Context), Size(0), Alignment(8), Packed(false),
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UnfilledBitsInLastByte(0), MaxFieldAlignment(0), DataSize(0), IsUnion(false),
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NonVirtualSize(0), NonVirtualAlignment(8), FirstNearlyEmptyVBase(0) { }
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/// IsNearlyEmpty - Indicates when a class has a vtable pointer, but
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/// no other data.
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bool ASTRecordLayoutBuilder::IsNearlyEmpty(const CXXRecordDecl *RD) const {
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// FIXME: Audit the corners
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if (!RD->isDynamicClass())
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return false;
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const ASTRecordLayout &BaseInfo = Context.getASTRecordLayout(RD);
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if (BaseInfo.getNonVirtualSize() == Context.Target.getPointerWidth(0))
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return true;
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return false;
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}
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void ASTRecordLayoutBuilder::IdentifyPrimaryBases(const CXXRecordDecl *RD) {
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const ASTRecordLayout::PrimaryBaseInfo &BaseInfo =
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Context.getASTRecordLayout(RD).getPrimaryBaseInfo();
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// If the record has a primary base class that is virtual, add it to the set
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// of primary bases.
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if (BaseInfo.isVirtual())
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IndirectPrimaryBases.insert(BaseInfo.getBase());
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// Now traverse all bases and find primary bases for them.
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for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
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e = RD->bases_end(); i != e; ++i) {
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assert(!i->getType()->isDependentType() &&
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"Cannot layout class with dependent bases.");
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const CXXRecordDecl *Base =
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cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
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// Only bases with virtual bases participate in computing the
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// indirect primary virtual base classes.
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if (Base->getNumVBases())
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IdentifyPrimaryBases(Base);
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}
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}
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void
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ASTRecordLayoutBuilder::SelectPrimaryVBase(const CXXRecordDecl *RD) {
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for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
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E = RD->bases_end(); I != E; ++I) {
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assert(!I->getType()->isDependentType() &&
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"Cannot layout class with dependent bases.");
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const CXXRecordDecl *Base =
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cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
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// Check if this is a nearly empty virtual base.
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if (I->isVirtual() && IsNearlyEmpty(Base)) {
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// If it's not an indirect primary base, then we've found our primary
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// base.
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if (!IndirectPrimaryBases.count(Base)) {
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PrimaryBase = ASTRecordLayout::PrimaryBaseInfo(Base,
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/*IsVirtual=*/true);
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return;
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}
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// Is this the first nearly empty virtual base?
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if (!FirstNearlyEmptyVBase)
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FirstNearlyEmptyVBase = Base;
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}
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SelectPrimaryVBase(Base);
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if (PrimaryBase.getBase())
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return;
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}
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}
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/// DeterminePrimaryBase - Determine the primary base of the given class.
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void ASTRecordLayoutBuilder::DeterminePrimaryBase(const CXXRecordDecl *RD) {
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// If the class isn't dynamic, it won't have a primary base.
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if (!RD->isDynamicClass())
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return;
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// Compute all the primary virtual bases for all of our direct and
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// indirect bases, and record all their primary virtual base classes.
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for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
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e = RD->bases_end(); i != e; ++i) {
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assert(!i->getType()->isDependentType() &&
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"Cannot lay out class with dependent bases.");
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const CXXRecordDecl *Base =
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cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
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IdentifyPrimaryBases(Base);
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}
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// If the record has a dynamic base class, attempt to choose a primary base
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// class. It is the first (in direct base class order) non-virtual dynamic
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// base class, if one exists.
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for (CXXRecordDecl::base_class_const_iterator i = RD->bases_begin(),
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e = RD->bases_end(); i != e; ++i) {
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// Ignore virtual bases.
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if (i->isVirtual())
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continue;
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const CXXRecordDecl *Base =
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cast<CXXRecordDecl>(i->getType()->getAs<RecordType>()->getDecl());
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if (Base->isDynamicClass()) {
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// We found it.
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PrimaryBase = ASTRecordLayout::PrimaryBaseInfo(Base, /*IsVirtual=*/false);
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return;
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}
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}
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// Otherwise, it is the first nearly empty virtual base that is not an
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// indirect primary virtual base class, if one exists.
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if (RD->getNumVBases() != 0) {
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SelectPrimaryVBase(RD);
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if (PrimaryBase.getBase())
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return;
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}
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// Otherwise, it is the first nearly empty virtual base that is not an
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// indirect primary virtual base class, if one exists.
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if (FirstNearlyEmptyVBase) {
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PrimaryBase = ASTRecordLayout::PrimaryBaseInfo(FirstNearlyEmptyVBase,
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/*IsVirtual=*/true);
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return;
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}
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// Otherwise there is no primary base class.
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assert(!PrimaryBase.getBase() && "Should not get here with a primary base!");
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// Allocate the virtual table pointer at offset zero.
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assert(DataSize == 0 && "Vtable pointer must be at offset zero!");
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// Update the size.
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Size += Context.Target.getPointerWidth(0);
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DataSize = Size;
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// Update the alignment.
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UpdateAlignment(Context.Target.getPointerAlign(0));
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}
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void
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ASTRecordLayoutBuilder::LayoutNonVirtualBases(const CXXRecordDecl *RD) {
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// First, determine the primary base class.
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DeterminePrimaryBase(RD);
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// If we have a primary base class, lay it out.
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if (const CXXRecordDecl *Base = PrimaryBase.getBase()) {
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if (PrimaryBase.isVirtual()) {
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// We have a virtual primary base, insert it as an indirect primary base.
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IndirectPrimaryBases.insert(Base);
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assert(!VisitedVirtualBases.count(Base) && "vbase already visited!");
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VisitedVirtualBases.insert(Base);
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LayoutVirtualBase(Base);
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} else
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LayoutNonVirtualBase(Base);
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}
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// Now lay out the non-virtual bases.
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for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
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E = RD->bases_end(); I != E; ++I) {
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// Ignore virtual bases.
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if (I->isVirtual())
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continue;
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const CXXRecordDecl *Base =
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cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
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// Skip the primary base.
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if (Base == PrimaryBase.getBase() && !PrimaryBase.isVirtual())
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continue;
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// Lay out the base.
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LayoutNonVirtualBase(Base);
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}
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}
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void ASTRecordLayoutBuilder::LayoutNonVirtualBase(const CXXRecordDecl *RD) {
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// Layout the base.
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uint64_t Offset = LayoutBase(RD);
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// Add its base class offset.
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if (!Bases.insert(std::make_pair(RD, Offset)).second)
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assert(false && "Added same base offset more than once!");
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}
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void
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ASTRecordLayoutBuilder::AddPrimaryVirtualBaseOffsets(const CXXRecordDecl *RD,
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uint64_t Offset,
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const CXXRecordDecl *MostDerivedClass) {
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// We already have the offset for the primary base of the most derived class.
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if (RD != MostDerivedClass) {
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const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
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const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBase();
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// If this is a primary virtual base and we haven't seen it before, add it.
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if (PrimaryBase && Layout.getPrimaryBaseWasVirtual() &&
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!VBases.count(PrimaryBase))
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VBases.insert(std::make_pair(PrimaryBase, Offset));
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}
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for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
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E = RD->bases_end(); I != E; ++I) {
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assert(!I->getType()->isDependentType() &&
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"Cannot layout class with dependent bases.");
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const CXXRecordDecl *BaseDecl =
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cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
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if (!BaseDecl->getNumVBases()) {
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// This base isn't interesting since it doesn't have any virtual bases.
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continue;
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}
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// Compute the offset of this base.
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uint64_t BaseOffset;
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if (I->isVirtual()) {
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// If we don't know this vbase yet, don't visit it. It will be visited
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// later.
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if (!VBases.count(BaseDecl)) {
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continue;
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}
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// Check if we've already visited this base.
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if (!VisitedVirtualBases.insert(BaseDecl))
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continue;
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// We want the vbase offset from the class we're currently laying out.
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BaseOffset = VBases[BaseDecl];
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} else if (RD == MostDerivedClass) {
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// We want the base offset from the class we're currently laying out.
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assert(Bases.count(BaseDecl) && "Did not find base!");
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BaseOffset = Bases[BaseDecl];
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} else {
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const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
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BaseOffset = Offset + Layout.getBaseClassOffset(BaseDecl);
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}
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AddPrimaryVirtualBaseOffsets(BaseDecl, BaseOffset, MostDerivedClass);
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}
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}
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void
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ASTRecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *RD,
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const CXXRecordDecl *MostDerivedClass) {
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const CXXRecordDecl *PrimaryBase;
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bool PrimaryBaseIsVirtual;
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if (MostDerivedClass == RD) {
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PrimaryBase = this->PrimaryBase.getBase();
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PrimaryBaseIsVirtual = this->PrimaryBase.isVirtual();
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} else {
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const ASTRecordLayout &Layout = Context.getASTRecordLayout(RD);
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PrimaryBase = Layout.getPrimaryBase();
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PrimaryBaseIsVirtual = Layout.getPrimaryBaseWasVirtual();
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}
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for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
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E = RD->bases_end(); I != E; ++I) {
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assert(!I->getType()->isDependentType() &&
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"Cannot layout class with dependent bases.");
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const CXXRecordDecl *Base =
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cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
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if (I->isVirtual()) {
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if (PrimaryBase != Base || !PrimaryBaseIsVirtual) {
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bool IndirectPrimaryBase = IndirectPrimaryBases.count(Base);
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// Only lay out the virtual base if it's not an indirect primary base.
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if (!IndirectPrimaryBase) {
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// Only visit virtual bases once.
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if (!VisitedVirtualBases.insert(Base))
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continue;
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LayoutVirtualBase(Base);
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}
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}
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}
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if (!Base->getNumVBases()) {
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// This base isn't interesting since it doesn't have any virtual bases.
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continue;
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}
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LayoutVirtualBases(Base, MostDerivedClass);
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}
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}
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void ASTRecordLayoutBuilder::LayoutVirtualBase(const CXXRecordDecl *RD) {
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// Layout the base.
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uint64_t Offset = LayoutBase(RD);
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// Add its base class offset.
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if (!VBases.insert(std::make_pair(RD, Offset)).second)
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assert(false && "Added same vbase offset more than once!");
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}
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uint64_t ASTRecordLayoutBuilder::LayoutBase(const CXXRecordDecl *RD) {
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const ASTRecordLayout &BaseInfo = Context.getASTRecordLayout(RD);
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// If we have an empty base class, try to place it at offset 0.
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if (RD->isEmpty() && canPlaceRecordAtOffset(RD, 0)) {
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// We were able to place the class at offset 0.
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UpdateEmptyClassOffsets(RD, 0);
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Size = std::max(Size, BaseInfo.getSize());
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return 0;
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}
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unsigned BaseAlign = BaseInfo.getNonVirtualAlign();
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// Round up the current record size to the base's alignment boundary.
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uint64_t Offset = llvm::RoundUpToAlignment(DataSize, BaseAlign);
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// Try to place the base.
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while (true) {
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if (canPlaceRecordAtOffset(RD, Offset))
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break;
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Offset += BaseAlign;
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}
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if (!RD->isEmpty()) {
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// Update the data size.
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DataSize = Offset + BaseInfo.getNonVirtualSize();
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Size = std::max(Size, DataSize);
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} else
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Size = std::max(Size, Offset + BaseInfo.getSize());
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// Remember max struct/class alignment.
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UpdateAlignment(BaseAlign);
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UpdateEmptyClassOffsets(RD, Offset);
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return Offset;
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}
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bool ASTRecordLayoutBuilder::canPlaceRecordAtOffset(const CXXRecordDecl *RD,
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uint64_t Offset) const {
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// Look for an empty class with the same type at the same offset.
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for (EmptyClassOffsetsTy::const_iterator I =
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EmptyClassOffsets.lower_bound(Offset),
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E = EmptyClassOffsets.upper_bound(Offset); I != E; ++I) {
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if (I->second == RD)
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return false;
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}
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const ASTRecordLayout &Info = Context.getASTRecordLayout(RD);
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// Check bases.
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for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
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E = RD->bases_end(); I != E; ++I) {
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assert(!I->getType()->isDependentType() &&
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"Cannot layout class with dependent bases.");
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if (I->isVirtual())
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continue;
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const CXXRecordDecl *Base =
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cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
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uint64_t BaseClassOffset = Info.getBaseClassOffset(Base);
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if (!canPlaceRecordAtOffset(Base, Offset + BaseClassOffset))
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return false;
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}
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// Check fields.
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unsigned FieldNo = 0;
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for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
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I != E; ++I, ++FieldNo) {
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const FieldDecl *FD = *I;
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uint64_t FieldOffset = Info.getFieldOffset(FieldNo);
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if (!canPlaceFieldAtOffset(FD, Offset + FieldOffset))
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return false;
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}
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// FIXME: virtual bases.
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return true;
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}
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bool ASTRecordLayoutBuilder::canPlaceFieldAtOffset(const FieldDecl *FD,
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uint64_t Offset) const {
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QualType T = FD->getType();
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if (const RecordType *RT = T->getAs<RecordType>()) {
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if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
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return canPlaceRecordAtOffset(RD, Offset);
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}
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if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
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QualType ElemTy = Context.getBaseElementType(AT);
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const RecordType *RT = ElemTy->getAs<RecordType>();
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if (!RT)
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return true;
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const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
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if (!RD)
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return true;
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const ASTRecordLayout &Info = Context.getASTRecordLayout(RD);
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uint64_t NumElements = Context.getConstantArrayElementCount(AT);
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uint64_t ElementOffset = Offset;
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for (uint64_t I = 0; I != NumElements; ++I) {
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if (!canPlaceRecordAtOffset(RD, ElementOffset))
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return false;
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ElementOffset += Info.getSize();
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}
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}
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return true;
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}
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void ASTRecordLayoutBuilder::UpdateEmptyClassOffsets(const CXXRecordDecl *RD,
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uint64_t Offset) {
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if (RD->isEmpty())
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EmptyClassOffsets.insert(std::make_pair(Offset, RD));
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const ASTRecordLayout &Info = Context.getASTRecordLayout(RD);
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// Update bases.
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for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
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E = RD->bases_end(); I != E; ++I) {
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assert(!I->getType()->isDependentType() &&
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"Cannot layout class with dependent bases.");
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if (I->isVirtual())
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continue;
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const CXXRecordDecl *Base =
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cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
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uint64_t BaseClassOffset = Info.getBaseClassOffset(Base);
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UpdateEmptyClassOffsets(Base, Offset + BaseClassOffset);
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}
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// Update fields.
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unsigned FieldNo = 0;
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for (CXXRecordDecl::field_iterator I = RD->field_begin(), E = RD->field_end();
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I != E; ++I, ++FieldNo) {
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const FieldDecl *FD = *I;
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uint64_t FieldOffset = Info.getFieldOffset(FieldNo);
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UpdateEmptyClassOffsets(FD, Offset + FieldOffset);
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}
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// FIXME: Update virtual bases.
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}
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void
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ASTRecordLayoutBuilder::UpdateEmptyClassOffsets(const FieldDecl *FD,
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uint64_t Offset) {
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QualType T = FD->getType();
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if (const RecordType *RT = T->getAs<RecordType>()) {
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if (const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
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UpdateEmptyClassOffsets(RD, Offset);
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return;
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}
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}
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if (const ConstantArrayType *AT = Context.getAsConstantArrayType(T)) {
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QualType ElemTy = Context.getBaseElementType(AT);
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const RecordType *RT = ElemTy->getAs<RecordType>();
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if (!RT)
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return;
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const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl());
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if (!RD)
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return;
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const ASTRecordLayout &Info = Context.getASTRecordLayout(RD);
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uint64_t NumElements = Context.getConstantArrayElementCount(AT);
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uint64_t ElementOffset = Offset;
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for (uint64_t I = 0; I != NumElements; ++I) {
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UpdateEmptyClassOffsets(RD, ElementOffset);
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ElementOffset += Info.getSize();
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}
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}
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}
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void ASTRecordLayoutBuilder::Layout(const RecordDecl *D) {
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IsUnion = D->isUnion();
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Packed = D->hasAttr<PackedAttr>();
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// The #pragma pack attribute specifies the maximum field alignment.
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if (const PragmaPackAttr *PPA = D->getAttr<PragmaPackAttr>())
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MaxFieldAlignment = PPA->getAlignment();
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|
|
if (const AlignedAttr *AA = D->getAttr<AlignedAttr>())
|
|
UpdateAlignment(AA->getMaxAlignment());
|
|
|
|
// If this is a C++ class, lay out the vtable and the non-virtual bases.
|
|
const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D);
|
|
if (RD)
|
|
LayoutNonVirtualBases(RD);
|
|
|
|
LayoutFields(D);
|
|
|
|
NonVirtualSize = Size;
|
|
NonVirtualAlignment = Alignment;
|
|
|
|
// If this is a C++ class, lay out its virtual bases and add its primary
|
|
// virtual base offsets.
|
|
if (RD) {
|
|
LayoutVirtualBases(RD, RD);
|
|
|
|
VisitedVirtualBases.clear();
|
|
AddPrimaryVirtualBaseOffsets(RD, 0, RD);
|
|
}
|
|
|
|
// Finally, round the size of the total struct up to the alignment of the
|
|
// struct itself.
|
|
FinishLayout();
|
|
|
|
#ifndef NDEBUG
|
|
if (RD) {
|
|
// Check that we have base offsets for all bases.
|
|
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
|
|
E = RD->bases_end(); I != E; ++I) {
|
|
if (I->isVirtual())
|
|
continue;
|
|
|
|
const CXXRecordDecl *BaseDecl =
|
|
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
|
|
|
|
assert(Bases.count(BaseDecl) && "Did not find base offset!");
|
|
}
|
|
|
|
// And all virtual bases.
|
|
for (CXXRecordDecl::base_class_const_iterator I = RD->vbases_begin(),
|
|
E = RD->vbases_end(); I != E; ++I) {
|
|
const CXXRecordDecl *BaseDecl =
|
|
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
|
|
|
|
assert(VBases.count(BaseDecl) && "Did not find base offset!");
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
|
|
// FIXME. Impl is no longer needed.
|
|
void ASTRecordLayoutBuilder::Layout(const ObjCInterfaceDecl *D,
|
|
const ObjCImplementationDecl *Impl) {
|
|
if (ObjCInterfaceDecl *SD = D->getSuperClass()) {
|
|
const ASTRecordLayout &SL = Context.getASTObjCInterfaceLayout(SD);
|
|
|
|
UpdateAlignment(SL.getAlignment());
|
|
|
|
// We start laying out ivars not at the end of the superclass
|
|
// structure, but at the next byte following the last field.
|
|
Size = llvm::RoundUpToAlignment(SL.getDataSize(), 8);
|
|
DataSize = Size;
|
|
}
|
|
|
|
Packed = D->hasAttr<PackedAttr>();
|
|
|
|
// The #pragma pack attribute specifies the maximum field alignment.
|
|
if (const PragmaPackAttr *PPA = D->getAttr<PragmaPackAttr>())
|
|
MaxFieldAlignment = PPA->getAlignment();
|
|
|
|
if (const AlignedAttr *AA = D->getAttr<AlignedAttr>())
|
|
UpdateAlignment(AA->getMaxAlignment());
|
|
// Layout each ivar sequentially.
|
|
llvm::SmallVector<ObjCIvarDecl*, 16> Ivars;
|
|
Context.ShallowCollectObjCIvars(D, Ivars);
|
|
for (unsigned i = 0, e = Ivars.size(); i != e; ++i)
|
|
LayoutField(Ivars[i]);
|
|
|
|
// Finally, round the size of the total struct up to the alignment of the
|
|
// struct itself.
|
|
FinishLayout();
|
|
}
|
|
|
|
void ASTRecordLayoutBuilder::LayoutFields(const RecordDecl *D) {
|
|
// Layout each field, for now, just sequentially, respecting alignment. In
|
|
// the future, this will need to be tweakable by targets.
|
|
for (RecordDecl::field_iterator Field = D->field_begin(),
|
|
FieldEnd = D->field_end(); Field != FieldEnd; ++Field)
|
|
LayoutField(*Field);
|
|
}
|
|
|
|
void ASTRecordLayoutBuilder::LayoutWideBitField(uint64_t FieldSize,
|
|
uint64_t TypeSize) {
|
|
assert(Context.getLangOptions().CPlusPlus &&
|
|
"Can only have wide bit-fields in C++!");
|
|
|
|
// Itanium C++ ABI 2.4:
|
|
// If sizeof(T)*8 < n, let T' be the largest integral POD type with
|
|
// sizeof(T')*8 <= n.
|
|
|
|
QualType IntegralPODTypes[] = {
|
|
Context.UnsignedCharTy, Context.UnsignedShortTy, Context.UnsignedIntTy,
|
|
Context.UnsignedLongTy, Context.UnsignedLongLongTy
|
|
};
|
|
|
|
QualType Type;
|
|
for (unsigned I = 0, E = llvm::array_lengthof(IntegralPODTypes);
|
|
I != E; ++I) {
|
|
uint64_t Size = Context.getTypeSize(IntegralPODTypes[I]);
|
|
|
|
if (Size > FieldSize)
|
|
break;
|
|
|
|
Type = IntegralPODTypes[I];
|
|
}
|
|
assert(!Type.isNull() && "Did not find a type!");
|
|
|
|
unsigned TypeAlign = Context.getTypeAlign(Type);
|
|
|
|
// We're not going to use any of the unfilled bits in the last byte.
|
|
UnfilledBitsInLastByte = 0;
|
|
|
|
// The bitfield is allocated starting at the next offset aligned appropriately
|
|
// for T', with length n bits.
|
|
uint64_t FieldOffset = llvm::RoundUpToAlignment(DataSize, TypeAlign);
|
|
|
|
if (IsUnion) {
|
|
DataSize = std::max(DataSize, FieldSize);
|
|
} else {
|
|
uint64_t NewSizeInBits = FieldOffset + FieldSize;
|
|
|
|
DataSize = llvm::RoundUpToAlignment(NewSizeInBits, 8);
|
|
UnfilledBitsInLastByte = DataSize - NewSizeInBits;
|
|
}
|
|
|
|
// Place this field at the current location.
|
|
FieldOffsets.push_back(FieldOffset);
|
|
|
|
// Update the size.
|
|
Size = std::max(Size, DataSize);
|
|
|
|
// Remember max struct/class alignment.
|
|
UpdateAlignment(TypeAlign);
|
|
}
|
|
|
|
void ASTRecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
|
|
bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
|
|
uint64_t FieldOffset = IsUnion ? 0 : (DataSize - UnfilledBitsInLastByte);
|
|
uint64_t FieldSize = D->getBitWidth()->EvaluateAsInt(Context).getZExtValue();
|
|
|
|
std::pair<uint64_t, unsigned> FieldInfo = Context.getTypeInfo(D->getType());
|
|
uint64_t TypeSize = FieldInfo.first;
|
|
unsigned FieldAlign = FieldInfo.second;
|
|
|
|
if (FieldSize > TypeSize) {
|
|
LayoutWideBitField(FieldSize, TypeSize);
|
|
return;
|
|
}
|
|
|
|
if (FieldPacked || !Context.Target.useBitFieldTypeAlignment())
|
|
FieldAlign = 1;
|
|
if (const AlignedAttr *AA = D->getAttr<AlignedAttr>())
|
|
FieldAlign = std::max(FieldAlign, AA->getMaxAlignment());
|
|
|
|
// The maximum field alignment overrides the aligned attribute.
|
|
if (MaxFieldAlignment)
|
|
FieldAlign = std::min(FieldAlign, MaxFieldAlignment);
|
|
|
|
// Check if we need to add padding to give the field the correct alignment.
|
|
if (FieldSize == 0 || (FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)
|
|
FieldOffset = (FieldOffset + (FieldAlign-1)) & ~(FieldAlign-1);
|
|
|
|
// Padding members don't affect overall alignment.
|
|
if (!D->getIdentifier())
|
|
FieldAlign = 1;
|
|
|
|
// Place this field at the current location.
|
|
FieldOffsets.push_back(FieldOffset);
|
|
|
|
// Update DataSize to include the last byte containing (part of) the bitfield.
|
|
if (IsUnion) {
|
|
// FIXME: I think FieldSize should be TypeSize here.
|
|
DataSize = std::max(DataSize, FieldSize);
|
|
} else {
|
|
uint64_t NewSizeInBits = FieldOffset + FieldSize;
|
|
|
|
DataSize = llvm::RoundUpToAlignment(NewSizeInBits, 8);
|
|
UnfilledBitsInLastByte = DataSize - NewSizeInBits;
|
|
}
|
|
|
|
// Update the size.
|
|
Size = std::max(Size, DataSize);
|
|
|
|
// Remember max struct/class alignment.
|
|
UpdateAlignment(FieldAlign);
|
|
}
|
|
|
|
void ASTRecordLayoutBuilder::LayoutField(const FieldDecl *D) {
|
|
if (D->isBitField()) {
|
|
LayoutBitField(D);
|
|
return;
|
|
}
|
|
|
|
// Reset the unfilled bits.
|
|
UnfilledBitsInLastByte = 0;
|
|
|
|
bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
|
|
uint64_t FieldOffset = IsUnion ? 0 : DataSize;
|
|
uint64_t FieldSize;
|
|
unsigned FieldAlign;
|
|
|
|
if (D->getType()->isIncompleteArrayType()) {
|
|
// This is a flexible array member; we can't directly
|
|
// query getTypeInfo about these, so we figure it out here.
|
|
// Flexible array members don't have any size, but they
|
|
// have to be aligned appropriately for their element type.
|
|
FieldSize = 0;
|
|
const ArrayType* ATy = Context.getAsArrayType(D->getType());
|
|
FieldAlign = Context.getTypeAlign(ATy->getElementType());
|
|
} else if (const ReferenceType *RT = D->getType()->getAs<ReferenceType>()) {
|
|
unsigned AS = RT->getPointeeType().getAddressSpace();
|
|
FieldSize = Context.Target.getPointerWidth(AS);
|
|
FieldAlign = Context.Target.getPointerAlign(AS);
|
|
} else {
|
|
std::pair<uint64_t, unsigned> FieldInfo = Context.getTypeInfo(D->getType());
|
|
FieldSize = FieldInfo.first;
|
|
FieldAlign = FieldInfo.second;
|
|
}
|
|
|
|
if (FieldPacked)
|
|
FieldAlign = 8;
|
|
if (const AlignedAttr *AA = D->getAttr<AlignedAttr>())
|
|
FieldAlign = std::max(FieldAlign, AA->getMaxAlignment());
|
|
|
|
// The maximum field alignment overrides the aligned attribute.
|
|
if (MaxFieldAlignment)
|
|
FieldAlign = std::min(FieldAlign, MaxFieldAlignment);
|
|
|
|
// Round up the current record size to the field's alignment boundary.
|
|
FieldOffset = llvm::RoundUpToAlignment(FieldOffset, FieldAlign);
|
|
|
|
if (!IsUnion) {
|
|
while (true) {
|
|
// Check if we can place the field at this offset.
|
|
if (canPlaceFieldAtOffset(D, FieldOffset))
|
|
break;
|
|
|
|
// We couldn't place the field at the offset. Try again at a new offset.
|
|
FieldOffset += FieldAlign;
|
|
}
|
|
|
|
UpdateEmptyClassOffsets(D, FieldOffset);
|
|
}
|
|
|
|
// Place this field at the current location.
|
|
FieldOffsets.push_back(FieldOffset);
|
|
|
|
// Reserve space for this field.
|
|
if (IsUnion)
|
|
Size = std::max(Size, FieldSize);
|
|
else
|
|
Size = FieldOffset + FieldSize;
|
|
|
|
// Update the data size.
|
|
DataSize = Size;
|
|
|
|
// Remember max struct/class alignment.
|
|
UpdateAlignment(FieldAlign);
|
|
}
|
|
|
|
void ASTRecordLayoutBuilder::FinishLayout() {
|
|
// In C++, records cannot be of size 0.
|
|
if (Context.getLangOptions().CPlusPlus && Size == 0)
|
|
Size = 8;
|
|
// Finally, round the size of the record up to the alignment of the
|
|
// record itself.
|
|
Size = llvm::RoundUpToAlignment(Size, Alignment);
|
|
}
|
|
|
|
void ASTRecordLayoutBuilder::UpdateAlignment(unsigned NewAlignment) {
|
|
if (NewAlignment <= Alignment)
|
|
return;
|
|
|
|
assert(llvm::isPowerOf2_32(NewAlignment && "Alignment not a power of 2"));
|
|
|
|
Alignment = NewAlignment;
|
|
}
|
|
|
|
const ASTRecordLayout *
|
|
ASTRecordLayoutBuilder::ComputeLayout(ASTContext &Ctx,
|
|
const RecordDecl *D) {
|
|
ASTRecordLayoutBuilder Builder(Ctx);
|
|
|
|
Builder.Layout(D);
|
|
|
|
if (!isa<CXXRecordDecl>(D))
|
|
return new (Ctx) ASTRecordLayout(Ctx, Builder.Size, Builder.Alignment,
|
|
Builder.Size,
|
|
Builder.FieldOffsets.data(),
|
|
Builder.FieldOffsets.size());
|
|
|
|
// FIXME: This is not always correct. See the part about bitfields at
|
|
// http://www.codesourcery.com/public/cxx-abi/abi.html#POD for more info.
|
|
// FIXME: IsPODForThePurposeOfLayout should be stored in the record layout.
|
|
bool IsPODForThePurposeOfLayout = cast<CXXRecordDecl>(D)->isPOD();
|
|
|
|
// FIXME: This should be done in FinalizeLayout.
|
|
uint64_t DataSize =
|
|
IsPODForThePurposeOfLayout ? Builder.Size : Builder.DataSize;
|
|
uint64_t NonVirtualSize =
|
|
IsPODForThePurposeOfLayout ? DataSize : Builder.NonVirtualSize;
|
|
|
|
return new (Ctx) ASTRecordLayout(Ctx, Builder.Size, Builder.Alignment,
|
|
DataSize, Builder.FieldOffsets.data(),
|
|
Builder.FieldOffsets.size(),
|
|
NonVirtualSize,
|
|
Builder.NonVirtualAlignment,
|
|
Builder.PrimaryBase,
|
|
Builder.Bases, Builder.VBases);
|
|
}
|
|
|
|
const ASTRecordLayout *
|
|
ASTRecordLayoutBuilder::ComputeLayout(ASTContext &Ctx,
|
|
const ObjCInterfaceDecl *D,
|
|
const ObjCImplementationDecl *Impl) {
|
|
ASTRecordLayoutBuilder Builder(Ctx);
|
|
|
|
Builder.Layout(D, Impl);
|
|
|
|
return new (Ctx) ASTRecordLayout(Ctx, Builder.Size, Builder.Alignment,
|
|
Builder.DataSize,
|
|
Builder.FieldOffsets.data(),
|
|
Builder.FieldOffsets.size());
|
|
}
|
|
|
|
const CXXMethodDecl *
|
|
ASTRecordLayoutBuilder::ComputeKeyFunction(const CXXRecordDecl *RD) {
|
|
assert(RD->isDynamicClass() && "Class does not have any virtual methods!");
|
|
|
|
// If a class isnt' polymorphic it doesn't have a key function.
|
|
if (!RD->isPolymorphic())
|
|
return 0;
|
|
|
|
// A class inside an anonymous namespace doesn't have a key function. (Or
|
|
// at least, there's no point to assigning a key function to such a class;
|
|
// this doesn't affect the ABI.)
|
|
if (RD->isInAnonymousNamespace())
|
|
return 0;
|
|
|
|
for (CXXRecordDecl::method_iterator I = RD->method_begin(),
|
|
E = RD->method_end(); I != E; ++I) {
|
|
const CXXMethodDecl *MD = *I;
|
|
|
|
if (!MD->isVirtual())
|
|
continue;
|
|
|
|
if (MD->isPure())
|
|
continue;
|
|
|
|
// Ignore implicit member functions, they are always marked as inline, but
|
|
// they don't have a body until they're defined.
|
|
if (MD->isImplicit())
|
|
continue;
|
|
|
|
if (MD->isInlineSpecified())
|
|
continue;
|
|
|
|
if (MD->hasInlineBody())
|
|
continue;
|
|
|
|
// We found it.
|
|
return MD;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void PrintOffset(llvm::raw_ostream &OS,
|
|
uint64_t Offset, unsigned IndentLevel) {
|
|
OS << llvm::format("%4d | ", Offset);
|
|
OS.indent(IndentLevel * 2);
|
|
}
|
|
|
|
static void DumpCXXRecordLayout(llvm::raw_ostream &OS,
|
|
const CXXRecordDecl *RD, ASTContext &C,
|
|
uint64_t Offset,
|
|
unsigned IndentLevel,
|
|
const char* Description,
|
|
bool IncludeVirtualBases) {
|
|
const ASTRecordLayout &Info = C.getASTRecordLayout(RD);
|
|
|
|
PrintOffset(OS, Offset, IndentLevel);
|
|
OS << C.getTypeDeclType((CXXRecordDecl *)RD).getAsString();
|
|
if (Description)
|
|
OS << ' ' << Description;
|
|
if (RD->isEmpty())
|
|
OS << " (empty)";
|
|
OS << '\n';
|
|
|
|
IndentLevel++;
|
|
|
|
const CXXRecordDecl *PrimaryBase = Info.getPrimaryBase();
|
|
|
|
// Vtable pointer.
|
|
if (RD->isDynamicClass() && !PrimaryBase) {
|
|
PrintOffset(OS, Offset, IndentLevel);
|
|
OS << '(' << RD->getNameAsString() << " vtable pointer)\n";
|
|
}
|
|
// Dump (non-virtual) bases
|
|
for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
|
|
E = RD->bases_end(); I != E; ++I) {
|
|
assert(!I->getType()->isDependentType() &&
|
|
"Cannot layout class with dependent bases.");
|
|
if (I->isVirtual())
|
|
continue;
|
|
|
|
const CXXRecordDecl *Base =
|
|
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
|
|
|
|
uint64_t BaseOffset = Offset + Info.getBaseClassOffset(Base) / 8;
|
|
|
|
DumpCXXRecordLayout(OS, Base, C, BaseOffset, IndentLevel,
|
|
Base == PrimaryBase ? "(primary base)" : "(base)",
|
|
/*IncludeVirtualBases=*/false);
|
|
}
|
|
|
|
// Dump fields.
|
|
uint64_t FieldNo = 0;
|
|
for (CXXRecordDecl::field_iterator I = RD->field_begin(),
|
|
E = RD->field_end(); I != E; ++I, ++FieldNo) {
|
|
const FieldDecl *Field = *I;
|
|
uint64_t FieldOffset = Offset + Info.getFieldOffset(FieldNo) / 8;
|
|
|
|
if (const RecordType *RT = Field->getType()->getAs<RecordType>()) {
|
|
if (const CXXRecordDecl *D = dyn_cast<CXXRecordDecl>(RT->getDecl())) {
|
|
DumpCXXRecordLayout(OS, D, C, FieldOffset, IndentLevel,
|
|
Field->getNameAsCString(),
|
|
/*IncludeVirtualBases=*/true);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
PrintOffset(OS, FieldOffset, IndentLevel);
|
|
OS << Field->getType().getAsString() << ' ';
|
|
OS << Field->getNameAsString() << '\n';
|
|
}
|
|
|
|
if (!IncludeVirtualBases)
|
|
return;
|
|
|
|
// Dump virtual bases.
|
|
for (CXXRecordDecl::base_class_const_iterator I = RD->vbases_begin(),
|
|
E = RD->vbases_end(); I != E; ++I) {
|
|
assert(I->isVirtual() && "Found non-virtual class!");
|
|
const CXXRecordDecl *VBase =
|
|
cast<CXXRecordDecl>(I->getType()->getAs<RecordType>()->getDecl());
|
|
|
|
uint64_t VBaseOffset = Offset + Info.getVBaseClassOffset(VBase) / 8;
|
|
DumpCXXRecordLayout(OS, VBase, C, VBaseOffset, IndentLevel,
|
|
VBase == PrimaryBase ?
|
|
"(primary virtual base)" : "(virtual base)",
|
|
/*IncludeVirtualBases=*/false);
|
|
}
|
|
}
|
|
|
|
void ASTContext::DumpRecordLayout(const RecordDecl *RD,
|
|
llvm::raw_ostream &OS) {
|
|
const ASTRecordLayout &Info = getASTRecordLayout(RD);
|
|
|
|
if (const CXXRecordDecl *CXXRD = dyn_cast<CXXRecordDecl>(RD))
|
|
DumpCXXRecordLayout(OS, CXXRD, *this, 0, 0, 0,
|
|
/*IncludeVirtualBases=*/true);
|
|
else
|
|
OS << getTypeDeclType(RD).getAsString();
|
|
|
|
OS << " sizeof=" << Info.getSize() / 8;
|
|
OS << ", dsize=" << Info.getDataSize() / 8;
|
|
OS << ", align=" << Info.getAlignment() / 8 << '\n';
|
|
OS << " nvsize=" << Info.getNonVirtualSize() / 8;
|
|
OS << ", nvalign=" << Info.getNonVirtualAlign() / 8 << '\n';
|
|
OS << '\n';
|
|
}
|