зеркало из https://github.com/microsoft/clang-1.git
761 строка
25 KiB
C++
761 строка
25 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/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 &Ctx)
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: Ctx(Ctx), Size(0), Alignment(8), Packed(false), UnfilledBitsInLastByte(0),
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MaxFieldAlignment(0), DataSize(0), IsUnion(false), NonVirtualSize(0),
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NonVirtualAlignment(8) { }
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/// LayoutVtable - Lay out the vtable and set PrimaryBase.
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void ASTRecordLayoutBuilder::LayoutVtable(const CXXRecordDecl *RD) {
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if (!RD->isDynamicClass()) {
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// There is no primary base in this case.
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return;
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}
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SelectPrimaryBase(RD);
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if (!PrimaryBase.getBase()) {
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int AS = 0;
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UpdateAlignment(Ctx.Target.getPointerAlign(AS));
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Size += Ctx.Target.getPointerWidth(AS);
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DataSize = Size;
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}
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}
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void
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ASTRecordLayoutBuilder::LayoutNonVirtualBases(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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if (!i->isVirtual()) {
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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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// Skip the PrimaryBase here, as it is laid down first.
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if (Base != PrimaryBase.getBase() || PrimaryBase.isVirtual())
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LayoutBaseNonVirtually(Base, false);
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}
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}
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}
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// Helper routines related to the abi definition from:
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// http://www.codesourcery.com/public/cxx-abi/abi.html
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//
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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 = Ctx.getASTRecordLayout(RD);
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if (BaseInfo.getNonVirtualSize() == Ctx.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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Ctx.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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const CXXRecordDecl *&FirstPrimary) {
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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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SelectPrimaryVBase(Base, FirstPrimary);
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if (PrimaryBase.getBase())
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return;
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continue;
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}
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if (IsNearlyEmpty(Base)) {
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if (FirstPrimary==0)
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FirstPrimary = Base;
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if (!IndirectPrimaryBases.count(Base)) {
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setPrimaryBase(Base, /*IsVirtual=*/true);
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return;
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}
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}
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assert(i->isVirtual());
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SelectPrimaryVBase(Base, FirstPrimary);
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if (PrimaryBase.getBase())
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return;
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}
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}
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/// SelectPrimaryBase - Selects the primary base for the given class and
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/// record that with setPrimaryBase. We also calculate the IndirectPrimaries.
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void ASTRecordLayoutBuilder::SelectPrimaryBase(const CXXRecordDecl *RD) {
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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 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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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 we have no virtual bases at this point, bail out as the searching below
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// is expensive.
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if (RD->getNumVBases() == 0)
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return;
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// Then we can search for the first nearly empty virtual base itself.
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const CXXRecordDecl *FirstPrimary = 0;
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SelectPrimaryVBase(RD, FirstPrimary);
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// Otherwise if is the first nearly empty virtual base, if one exists,
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// otherwise there is no primary base class.
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if (!PrimaryBase.getBase())
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setPrimaryBase(FirstPrimary, /*IsVirtual=*/true);
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}
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void ASTRecordLayoutBuilder::LayoutVirtualBase(const CXXRecordDecl *RD) {
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LayoutBaseNonVirtually(RD, true);
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}
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uint64_t ASTRecordLayoutBuilder::getBaseOffset(const CXXRecordDecl *Base) {
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for (size_t i = 0; i < Bases.size(); ++i) {
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if (Bases[i].first == Base)
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return Bases[i].second;
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}
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for (size_t i = 0; i < VBases.size(); ++i) {
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if (VBases[i].first == Base)
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return VBases[i].second;
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}
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assert(0 && "missing base");
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return 0;
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}
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void ASTRecordLayoutBuilder::LayoutVirtualBases(const CXXRecordDecl *Class,
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const CXXRecordDecl *RD,
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const CXXRecordDecl *PB,
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uint64_t Offset,
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llvm::SmallSet<const CXXRecordDecl*, 32> &mark,
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llvm::SmallSet<const CXXRecordDecl*, 32> &IndirectPrimary) {
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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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uint64_t BaseOffset = Offset;
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if (i->isVirtual()) {
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if (Base == PB) {
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// Only lay things out once.
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if (mark.count(Base))
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continue;
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// Mark it so we don't lay it out twice.
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mark.insert(Base);
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assert (IndirectPrimary.count(Base) && "IndirectPrimary was wrong");
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VBases.push_back(std::make_pair(Base, Offset));
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} else if (IndirectPrimary.count(Base)) {
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// Someone else will eventually lay this out.
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;
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} else {
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// Only lay things out once.
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if (mark.count(Base))
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continue;
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// Mark it so we don't lay it out twice.
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mark.insert(Base);
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LayoutVirtualBase(Base);
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BaseOffset = VBases.back().second;
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}
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} else {
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if (RD == Class)
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BaseOffset = getBaseOffset(Base);
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else {
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const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(RD);
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BaseOffset = Offset + Layout.getBaseClassOffset(Base);
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}
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}
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if (Base->getNumVBases()) {
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const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(Base);
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const CXXRecordDecl *PrimaryBase = Layout.getPrimaryBaseInfo().getBase();
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LayoutVirtualBases(Class, Base, PrimaryBase, BaseOffset, mark,
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IndirectPrimary);
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}
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}
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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 = Ctx.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 = Ctx.getAsConstantArrayType(T)) {
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QualType ElemTy = Ctx.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 = Ctx.getASTRecordLayout(RD);
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uint64_t NumElements = Ctx.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 = Ctx.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 = Ctx.getAsConstantArrayType(T)) {
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QualType ElemTy = Ctx.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 = Ctx.getASTRecordLayout(RD);
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uint64_t NumElements = Ctx.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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uint64_t ASTRecordLayoutBuilder::LayoutBase(const CXXRecordDecl *RD) {
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const ASTRecordLayout &BaseInfo = Ctx.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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void ASTRecordLayoutBuilder::LayoutBaseNonVirtually(const CXXRecordDecl *RD,
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bool IsVirtualBase) {
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// Layout the base.
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uint64_t Offset = LayoutBase(RD);
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// Add base class offsets.
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if (IsVirtualBase)
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VBases.push_back(std::make_pair(RD, Offset));
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else
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Bases.push_back(std::make_pair(RD, Offset));
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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>())
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UpdateAlignment(AA->getMaxAlignment());
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// If this is a C++ class, lay out the vtable and the non-virtual bases.
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const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(D);
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if (RD) {
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LayoutVtable(RD);
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// PrimaryBase goes first.
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if (PrimaryBase.getBase()) {
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if (PrimaryBase.isVirtual())
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IndirectPrimaryBases.insert(PrimaryBase.getBase());
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LayoutBaseNonVirtually(PrimaryBase.getBase(), PrimaryBase.isVirtual());
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}
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LayoutNonVirtualBases(RD);
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}
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LayoutFields(D);
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NonVirtualSize = Size;
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NonVirtualAlignment = Alignment;
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if (RD) {
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llvm::SmallSet<const CXXRecordDecl*, 32> mark;
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LayoutVirtualBases(RD, RD, PrimaryBase.getBase(),
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0, mark, IndirectPrimaryBases);
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}
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// Finally, round the size of the total struct up to the alignment of the
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// struct itself.
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FinishLayout();
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}
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// FIXME. Impl is no longer needed.
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void ASTRecordLayoutBuilder::Layout(const ObjCInterfaceDecl *D,
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const ObjCImplementationDecl *Impl) {
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if (ObjCInterfaceDecl *SD = D->getSuperClass()) {
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const ASTRecordLayout &SL = Ctx.getASTObjCInterfaceLayout(SD);
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UpdateAlignment(SL.getAlignment());
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// We start laying out ivars not at the end of the superclass
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// structure, but at the next byte following the last field.
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Size = llvm::RoundUpToAlignment(SL.getDataSize(), 8);
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DataSize = Size;
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}
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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>())
|
|
MaxFieldAlignment = PPA->getAlignment();
|
|
|
|
if (const AlignedAttr *AA = D->getAttr<AlignedAttr>())
|
|
UpdateAlignment(AA->getMaxAlignment());
|
|
// Layout each ivar sequentially.
|
|
llvm::SmallVector<ObjCIvarDecl*, 16> Ivars;
|
|
Ctx.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::LayoutBitField(const FieldDecl *D) {
|
|
bool FieldPacked = Packed || D->hasAttr<PackedAttr>();
|
|
uint64_t FieldOffset = IsUnion ? 0 : (DataSize - UnfilledBitsInLastByte);
|
|
uint64_t FieldSize = D->getBitWidth()->EvaluateAsInt(Ctx).getZExtValue();
|
|
|
|
std::pair<uint64_t, unsigned> FieldInfo = Ctx.getTypeInfo(D->getType());
|
|
uint64_t TypeSize = FieldInfo.first;
|
|
unsigned FieldAlign = FieldInfo.second;
|
|
|
|
if (FieldPacked)
|
|
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 = Ctx.getAsArrayType(D->getType());
|
|
FieldAlign = Ctx.getTypeAlign(ATy->getElementType());
|
|
} else if (const ReferenceType *RT = D->getType()->getAs<ReferenceType>()) {
|
|
unsigned AS = RT->getPointeeType().getAddressSpace();
|
|
FieldSize = Ctx.Target.getPointerWidth(AS);
|
|
FieldAlign = Ctx.Target.getPointerAlign(AS);
|
|
} else {
|
|
std::pair<uint64_t, unsigned> FieldInfo = Ctx.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 (Ctx.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 ASTRecordLayout(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 ASTRecordLayout(Builder.Size, Builder.Alignment, DataSize,
|
|
Builder.FieldOffsets.data(),
|
|
Builder.FieldOffsets.size(),
|
|
NonVirtualSize,
|
|
Builder.NonVirtualAlignment,
|
|
Builder.PrimaryBase,
|
|
Builder.Bases.data(),
|
|
Builder.Bases.size(),
|
|
Builder.VBases.data(),
|
|
Builder.VBases.size());
|
|
}
|
|
|
|
const ASTRecordLayout *
|
|
ASTRecordLayoutBuilder::ComputeLayout(ASTContext &Ctx,
|
|
const ObjCInterfaceDecl *D,
|
|
const ObjCImplementationDecl *Impl) {
|
|
ASTRecordLayoutBuilder Builder(Ctx);
|
|
|
|
Builder.Layout(D, Impl);
|
|
|
|
return new ASTRecordLayout(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;
|
|
}
|
|
|