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/******************************************************************************
*
* C++ Insights, copyright (C) by Andreas Fertig
* Distributed under an MIT license. See LICENSE for details
*
****************************************************************************/
#include <clang/AST/VTableBuilder.h>
#include <algorithm>
#include <vector>
#include "CodeGenerator.h"
#include "DPrint.h"
#include "Insights.h"
#include "InsightsHelpers.h"
#include "InsightsOnce.h"
#include "InsightsStrCat.h"
#include "NumberIterator.h"
#include "ASTHelpers.h"
//-----------------------------------------------------------------------------
namespace clang::insights {
using namespace asthelpers;
//-----------------------------------------------------------------------------
//! Store the `this` pointer offset from derived to base class.
static llvm::DenseMap<std::pair<const CXXRecordDecl*, const CXXRecordDecl*>, int> mThisPointerOffset{};
//-----------------------------------------------------------------------------
static MemberExpr* AccessMember(std::string_view name, const ValueDecl* vd, QualType type)
{
auto* rhsDeclRef = mkVarDeclRefExpr(name, type);
auto* rhsMemberExpr = AccessMember(rhsDeclRef, vd);
return rhsMemberExpr;
}
//-----------------------------------------------------------------------------
CfrontCodeGenerator::CfrontVtableData::CfrontVtableData()
: vptpTypedef{Typedef("__vptp"sv, Function("vptp"sv, GetGlobalAST().IntTy, {})->getType())}
, vtableRecorDecl{}
{
vtableRecorDecl = Struct("__mptr"sv);
auto AddField = [&](FieldDecl* field) { vtableRecorDecl->addDecl(field); };
d = mkFieldDecl(vtableRecorDecl, "d"sv, GetGlobalAST().ShortTy);
AddField(d);
AddField(mkFieldDecl(vtableRecorDecl, "i"sv, GetGlobalAST().ShortTy));
f = mkFieldDecl(vtableRecorDecl, "f"sv, vptpTypedef);
AddField(f);
vtableRecorDecl->completeDefinition();
vtableRecordType =
#if IS_CLANG_NEWER_THAN(22)
vtableRecorDecl->getASTContext().getCanonicalTagType(vtableRecorDecl);
#else
QualType{vtableRecorDecl->getTypeForDecl(), 0u};
#endif
}
//-----------------------------------------------------------------------------
VarDecl* CfrontCodeGenerator::CfrontVtableData::VtblArrayVar(int size)
{
return Variable("__vtbl_array"sv, ContantArrayTy(Ptr(vtableRecordType), size));
}
//-----------------------------------------------------------------------------
FieldDecl* CfrontCodeGenerator::CfrontVtableData::VtblPtrField(const CXXRecordDecl* parent)
{
return mkFieldDecl(const_cast<CXXRecordDecl*>(parent), StrCat("__vptr"sv, GetName(*parent)), Ptr(vtableRecordType));
}
//-----------------------------------------------------------------------------
CfrontCodeGenerator::CfrontVtableData& CfrontCodeGenerator::VtableData()
{
static CfrontVtableData data{};
return data;
}
//-----------------------------------------------------------------------------
CodeGeneratorVariant::CodeGenerators::CodeGenerators(OutputFormatHelper& _outputFormatHelper,
CodeGenerator::LambdaStackType& lambdaStack,
CodeGenerator::ProcessingPrimaryTemplate processingPrimaryTemplate)
{
if(GetInsightsOptions().UseShow2C) {
new(&cfcg) CfrontCodeGenerator{_outputFormatHelper, lambdaStack, processingPrimaryTemplate};
} else {
new(&cg) CodeGenerator{_outputFormatHelper, lambdaStack, processingPrimaryTemplate};
}
}
//-----------------------------------------------------------------------------
CodeGeneratorVariant::CodeGenerators::CodeGenerators(OutputFormatHelper& _outputFormatHelper)
{
if(GetInsightsOptions().UseShow2C) {
new(&cfcg) CfrontCodeGenerator{_outputFormatHelper};
} else {
new(&cg) CodeGenerator{_outputFormatHelper};
}
}
//-----------------------------------------------------------------------------
CodeGeneratorVariant::CodeGenerators::~CodeGenerators()
{
if(GetInsightsOptions().UseShow2C) {
cfcg.~CfrontCodeGenerator();
} else {
cg.~CodeGenerator();
}
}
//-----------------------------------------------------------------------------
void CodeGeneratorVariant::Set()
{
if(GetInsightsOptions().UseShow2C) {
cg = &cgs.cfcg;
} else {
cg = &cgs.cg;
}
}
//-----------------------------------------------------------------------------
static bool IsCopyOrMoveCtor(const CXXConstructorDecl* ctor)
{
return ctor and (ctor->isCopyConstructor() or ctor->isMoveConstructor());
}
//-----------------------------------------------------------------------------
static bool IsCopyOrMoveAssign(const CXXMethodDecl* stmt)
{
return stmt and (stmt->isCopyAssignmentOperator() or stmt->isMoveAssignmentOperator());
}
//-----------------------------------------------------------------------------
static std::string GetSpecialMemberName(const ValueDecl* vd, QualType type)
{
if(const auto* md = dyn_cast_or_null<CXXMethodDecl>(vd)) {
// GetName below would return a[4] for example. To avoid the array part we go for the underlying type.
if(const auto* ar = dyn_cast_or_null<ArrayType>(type)) {
type = ar->getElementType();
}
auto rdName = GetName(type);
if(const auto* ctor = dyn_cast_or_null<CXXConstructorDecl>(md)) {
if(ctor->isCopyConstructor()) {
return StrCat("CopyConstructor_"sv, rdName);
} else if(ctor->isMoveConstructor()) {
return StrCat("MoveConstructor_"sv, rdName);
}
return StrCat("Constructor_"sv, rdName);
} else if(isa<CXXDestructorDecl>(md)) {
return StrCat("Destructor_"sv, rdName);
}
}
return GetName(*vd);
}
//-----------------------------------------------------------------------------
std::string GetSpecialMemberName(const ValueDecl* vd)
{
if(const auto* md = dyn_cast_or_null<CXXMethodDecl>(vd)) {
return GetSpecialMemberName(vd, GetRecordDeclType(md));
}
return {};
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::InsertArg(const CXXThisExpr*)
{
mOutputFormatHelper.Append(kwInternalThis);
}
//-----------------------------------------------------------------------------
static bool HasCtor(QualType t)
{
if(auto* cxxRecordDecl = t->getAsCXXRecordDecl(); cxxRecordDecl and not cxxRecordDecl->isTrivial()) {
return true;
}
return false;
}
//-----------------------------------------------------------------------------
static bool HasDtor(QualType t)
{
if(auto* cxxRecordDecl = t->getAsCXXRecordDecl(); cxxRecordDecl and not cxxRecordDecl->hasTrivialDestructor()) {
return true;
}
return false;
}
//-----------------------------------------------------------------------------
static auto* CallVecDeleteOrDtor(Expr* objectParam, QualType allocatedType, std::string_view name, uint64_t size)
{
auto dtorName = GetSpecialMemberName(allocatedType->getAsCXXRecordDecl()->getDestructor());
SmallVector<Expr*, 4> args{objectParam,
Sizeof(allocatedType),
Int32(size), // XXX what is the correct value?
CastToVoidFunPtr(dtorName)};
return Call(name, args);
}
//-----------------------------------------------------------------------------
static auto* CallVecDelete(Expr* objectParam, QualType allocatedType)
{
EnableGlobalInsert(GlobalInserts::FuncCxaVecDel);
return CallVecDeleteOrDtor(objectParam, allocatedType, "__cxa_vec_delete"sv, 0);
}
//-----------------------------------------------------------------------------
static auto* CallVecDtor(Expr* objectParam, const ConstantArrayType* ar)
{
EnableGlobalInsert(GlobalInserts::FuncCxaVecDtor);
return CallVecDeleteOrDtor(objectParam, ar->getElementType(), "__cxa_vec_dtor"sv, GetSize(ar));
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::InsertArg(const CXXDeleteExpr* stmt)
{
auto destroyedType = stmt->getDestroyedType();
auto* arg = const_cast<Expr*>(stmt->getArgument());
StmtsContainer bodyStmts{};
if(const auto hasDtor{HasDtor(destroyedType)}; stmt->isArrayForm() and hasDtor) {
bodyStmts.Add(CallVecDelete(arg, destroyedType));
} else if(hasDtor) {
bodyStmts.Add(Call(StrCat("Destructor_"sv, GetName(destroyedType)), {arg}));
}
EnableGlobalInsert(GlobalInserts::FuncFree);
bodyStmts.Add(Call("free"sv, {arg}));
InsertArg(If(arg, {bodyStmts}));
mInsertSemi = false; // Since we tamper with a CompoundStmt we signal _not_ to insert the usual semi
}
//-----------------------------------------------------------------------------
static auto* CallVecNewOrCtor(std::string_view ctorName,
Expr* objectParam,
QualType allocatedType,
Expr* arraySizeExpr,
std::string_view funName)
{
// According to "Inside the C++ Object Model" the dtor is required in case one of the array element ctors fails the
// already constructed one must be destroyed.
// See also: https://itanium-cxx-abi.github.io/cxx-abi/abi.html#array-ctor
auto dtorName = [&]() {
if(HasDtor(allocatedType)) {
return GetSpecialMemberName(allocatedType->getAsCXXRecordDecl()->getDestructor());
}
return std::string{kwNull};
}();
SmallVector<Expr*, 6> args{objectParam,
Sizeof(allocatedType),
arraySizeExpr,
Int32(0), // XXX what is the correct value?
CastToVoidFunPtr(ctorName),
CastToVoidFunPtr(dtorName)};
return Call(funName, args);
}
//-----------------------------------------------------------------------------
static auto* CallVecNew(std::string_view ctorName, Expr* objectParam, QualType allocatedType, Expr* arraySizeExpr)
{
EnableGlobalInsert(GlobalInserts::FuncCxaVecNew);
return CallVecNewOrCtor(ctorName, objectParam, allocatedType, arraySizeExpr, "__cxa_vec_new"sv);
}
//-----------------------------------------------------------------------------
static auto*
CallVecCtor(std::string_view ctorName, const VarDecl* objectParam, QualType allocatedType, Expr* arraySizeExpr)
{
EnableGlobalInsert(GlobalInserts::FuncCxaVecCtor);
return CallVecNewOrCtor(ctorName, mkDeclRefExpr(objectParam), allocatedType, arraySizeExpr, "__cxa_vec_ctor"sv);
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::InsertArg(const CXXNewExpr* cstmt)
{
auto* stmt = const_cast<CXXNewExpr*>(cstmt);
auto allocatedType = stmt->getAllocatedType();
auto ctorName = StrCat("Constructor_"sv, GetName(allocatedType));
if(stmt->isArray()) {
EnableGlobalInsert(GlobalInserts::FuncMalloc);
auto* arraySizeExpr = stmt->getArraySize().value();
auto* callMalloc = Call("malloc"sv, {Mul(Sizeof(allocatedType), arraySizeExpr)});
Expr* assign{};
// According to "Inside the C++ Object Model" a trivial and literal type does use plain malloc as it does not
// require a ctor/dtor.
if(not HasCtor(allocatedType) and not HasDtor(allocatedType)) {
assign = Cast(callMalloc, Ptr(allocatedType));
} else {
if(allocatedType->getAsCXXRecordDecl()->ctors().empty()) {
EnableGlobalInsert(GlobalInserts::HeaderStddef);
ctorName = kwNull;
}
assign = Cast(CallVecNew(ctorName, callMalloc, allocatedType, arraySizeExpr), Ptr(allocatedType));
}
InsertArg(assign);
if(stmt->hasInitializer() and allocatedType->isBuiltinType()) { // Ignore CXXConstructExpr
// The resulting code here is slightly different from the cfront code. For
//
// int* p = new int(2);
//
// C++ Insights generates:
//
// int* p = (int*)malloc(sizeof(int));
// if(p) { *p = 2; }
//
// However, due to Cs requirement to only declare variables and delay initialization the cfront code is
//
// int* p;
// if(p = (int*)malloc(sizeof(int))) { *p = 2; }
mOutputFormatHelper.AppendSemiNewLine();
if(auto* inits = dyn_cast_or_null<InitListExpr>(stmt->getInitializer())) {
auto* expr = [&]() -> const Expr* {
if(auto* vd = dyn_cast_or_null<VarDecl>(mLastDecl)) {
return mkDeclRefExpr(vd);
}
return mLastExpr;
}();
StmtsContainer bodyStmts{};
for(auto idx : NumberIterator(inits->getNumInits())) {
bodyStmts.Add(Assign(ArraySubscript(expr, idx, allocatedType), inits->getInit(idx)));
}
InsertArg(If(expr, {bodyStmts}));
mInsertSemi = false; // Since we tamper with a CompoundStmt we signal _not_ to insert the usual semi
}
}
return;
}
auto* mallocCall = [&]() -> Expr* {
if(stmt->getNumPlacementArgs()) {
return stmt->getPlacementArg(0);
}
EnableGlobalInsert(GlobalInserts::FuncMalloc);
return Call("malloc"sv, {Sizeof(allocatedType)});
}();
mallocCall = Cast(mallocCall, Ptr(allocatedType));
if(allocatedType->isBuiltinType()) {
InsertArg(mallocCall);
if(stmt->hasInitializer()) {
// The resulting code here is slightly different from the cfront code. For
//
// int* p = new int(2);
//
// C++ Insights generates:
//
// int* p = (int*)malloc(sizeof(int));
// if(p) { *p = 2; }
//
// However, due to Cs requirement to only declare variables and delay initialization the cfront code is
//
// int* p;
// if(p = (int*)malloc(sizeof(int))) { *p = 2; }
mOutputFormatHelper.AppendSemiNewLine();
auto* varDeclRefExpr = mkDeclRefExpr(dyn_cast_or_null<VarDecl>(mLastDecl));
StmtsContainer bodyStmts{Assign(Dref(varDeclRefExpr), stmt->getInitializer())};
InsertArg(If(varDeclRefExpr, {bodyStmts}));
mInsertSemi = false; // Since we tamper with a CompoundStmt we signal _not_ to insert the usual semi
}
return;
}
SmallVector<Expr*, 16> args{mallocCall};
if(auto* ncCtorExpr = const_cast<CXXConstructExpr*>(stmt->getConstructExpr())) {
args.append(ncCtorExpr->arg_begin(), ncCtorExpr->arg_end());
}
InsertArg(Call(ctorName, args));
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::InsertArg(const CXXOperatorCallExpr* stmt)
{
const auto* callee = stmt->getDirectCallee();
if(const auto* cxxCallee = dyn_cast_or_null<CXXMethodDecl>(callee); IsCopyOrMoveAssign(cxxCallee)) {
SmallVector<Expr*, 16> args{};
for(const auto& arg : stmt->arguments()) {
args.push_back(Ref(arg));
}
InsertArg(Call(callee, args));
} else {
InsertArg(dyn_cast_or_null<CallExpr>(stmt));
}
}
//-----------------------------------------------------------------------------
static void InsertVtblPtr(const CXXMethodDecl* stmt, const CXXRecordDecl* cur, StmtsContainer& bodyStmts)
{
if(cur->isPolymorphic() and (0 == cur->getNumBases())) {
auto* fieldDecl = CfrontCodeGenerator::VtableData().VtblPtrField(cur);
auto* lhsMemberExpr = AccessMember(kwInternalThis, fieldDecl, Ptr(GetRecordDeclType(cur)));
// struct __mptr *__ptbl_vec__c___src_C_[]
auto* vtablAr = CfrontCodeGenerator::VtableData().VtblArrayVar(1);
auto* vtblArrayPos =
ArraySubscript(mkDeclRefExpr(vtablAr), GetGlobalVtablePos(stmt->getParent(), cur), fieldDecl->getType());
bodyStmts.AddBodyStmts(Assign(lhsMemberExpr, fieldDecl, vtblArrayPos));
} else if(cur->isPolymorphic() and (0 < cur->getNumBases()) and (cur != stmt->getParent())) {
for(const auto& base : cur->bases()) {
InsertVtblPtr(stmt, base.getType()->getAsCXXRecordDecl(), bodyStmts);
}
}
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::InsertCXXMethodDecl(const CXXMethodDecl* stmt, SkipBody)
{
// Skip if he method is unused like assignment operators by default.
RETURN_IF(not stmt->isUsed() and
(IsCopyOrMoveAssign(stmt) or (not stmt->hasBody() and not isa<CXXConstructorDecl>(stmt))));
OutputFormatHelper initOutputFormatHelper{};
initOutputFormatHelper.SetIndent(mOutputFormatHelper, OutputFormatHelper::SkipIndenting::Yes);
auto recordDeclType = GetRecordDeclType(stmt);
if(stmt->isConst()) {
recordDeclType.addConst();
}
auto parentType = Ptr(recordDeclType);
auto* body = stmt->getBody();
StmtsContainer bodyStmts{};
auto retType = stmt->getReturnType();
auto processBaseClassesAndFields = [&](const CXXRecordDecl* parent) {
auto* thisOfParent = mkVarDeclRefExpr(kwInternalThis, parentType);
auto insertFields = [&](const RecordDecl* rd) {
for(auto* fieldDecl : rd->fields()) {
if(const auto* cxxRecordDecl = fieldDecl->getType()->getAsCXXRecordDecl()) {
// We don't need any checks like isDefaultConstructible. We would not reach this
// point in any other case.
auto lvalueRefType = GetGlobalAST().getLValueReferenceType(parentType);
auto* lhsMemberExpr = AccessMember(kwInternalThis, fieldDecl, lvalueRefType);
auto* rhsMemberExpr = AccessMember("__rhs"sv, fieldDecl, lvalueRefType);
// Add call to ctor
bodyStmts.AddBodyStmts(Call(GetSpecialMemberName(stmt, GetRecordDeclType(cxxRecordDecl)),
{Ref(lhsMemberExpr), Ref(rhsMemberExpr)}));
} else {
auto* rhsMemberExpr = AccessMember("__rhs"sv, fieldDecl, parentType);
bodyStmts.AddBodyStmts(Assign(thisOfParent, fieldDecl, rhsMemberExpr));
}
}
};
for(const auto& base : parent->bases()) {
const auto rd = base.getType()->getAsRecordDecl();
auto* lhsCast = StaticCast(GetRecordDeclType(rd), thisOfParent, true);
auto* rhsDeclRef = mkVarDeclRefExpr("__rhs"sv, parentType);
auto* rhsCast = StaticCast(GetRecordDeclType(rd), rhsDeclRef, true);
auto* callAssignBase = Call(GetSpecialMemberName(stmt, GetRecordDeclType(rd)), {lhsCast, rhsCast});
bodyStmts.AddBodyStmts(callAssignBase);
}
// insert own fields
insertFields(parent);
};
// Skip ctor for trivial types
if(const auto* ctorDecl = dyn_cast_or_null<CXXConstructorDecl>(stmt)) {
const auto* parent = stmt->getParent();
if(not stmt->doesThisDeclarationHaveABody()) {
if(IsCopyOrMoveCtor(ctorDecl)) {
if(const bool showSpecialMemberFunc{stmt->isUserProvided() or stmt->isExplicitlyDefaulted()};
not showSpecialMemberFunc) {
return;
}
processBaseClassesAndFields(parent);
}
} else if(ctorDecl->isDefaultConstructor()) {
auto insertFields = [&](const RecordDecl* rd) {
for(auto* fieldDecl : rd->fields()) {
if(auto* initializer = fieldDecl->getInClassInitializer();
initializer and fieldDecl->hasInClassInitializer()) {
const bool isConstructorExpr{isa<CXXConstructExpr>(initializer) or
isa<ExprWithCleanups>(initializer)};
if(not isConstructorExpr) {
auto* lhsMemberExpr = AccessMember(kwInternalThis, fieldDecl, Ptr(GetRecordDeclType(rd)));
bodyStmts.AddBodyStmts(Assign(lhsMemberExpr, fieldDecl, initializer));
} else {
bodyStmts.AddBodyStmts(CallConstructor(fieldDecl->getType(),
Ptr(GetRecordDeclType(rd)),
fieldDecl,
ArgsToExprVector(initializer),
DoCast::No,
AsReference::Yes));
}
} else if(const auto* cxxRecordDecl = fieldDecl->getType()->getAsCXXRecordDecl()) {
// We don't need any checks like isDefaultConstructible. We would not reach this
// point in any other cause.
if(auto lhsType = fieldDecl->getType(); HasCtor(lhsType)) {
bodyStmts.AddBodyStmts(CallConstructor(GetRecordDeclType(cxxRecordDecl),
Ptr(GetRecordDeclType(cxxRecordDecl)),
fieldDecl,
{},
DoCast::No,
AsReference::Yes));
} else {
bodyStmts.Add(
Comment(StrCat(GetName(*fieldDecl), " // trivial type, maybe uninitialized"sv)));
// Nothing to do here, we are looking at an uninitialized variable
}
}
}
};
for(const auto& base : parent->bases()) {
auto baseType = base.getType();
if(const auto* baseRd = baseType->getAsCXXRecordDecl();
baseRd and baseRd->hasNonTrivialDefaultConstructor()) {
bodyStmts.AddBodyStmts(CallConstructor(baseType, Ptr(baseType), nullptr, {}, DoCast::Yes));
}
}
// insert our vtable pointer
InsertVtblPtr(stmt, stmt->getParent(), bodyStmts);
// in case of multi inheritance insert additional vtable pointers
for(const auto& base : parent->bases()) {
InsertVtblPtr(stmt, base.getType()->getAsCXXRecordDecl(), bodyStmts);
}
// insert own fields
insertFields(parent);
} else {
// user ctor
for(const auto* init : ctorDecl->inits()) {
auto* member = init->getMember();
if(not isa<CXXConstructExpr>(init->getInit())) {
if(not init->getAnyMember()) {
continue;
}
auto* lhsMemberExpr = AccessMember(kwInternalThis, member, Ptr(GetRecordDeclType(parent)));
bodyStmts.AddBodyStmts(Assign(lhsMemberExpr, member, init->getInit()));
continue;
} else if(init->isBaseInitializer()) {
bodyStmts.AddBodyStmts(init->getInit());
continue;
}
auto ctorType = member->getType();
auto* lhsMemberExpr = AccessMember(kwInternalThis, member, ctorType);
auto callParams{ArgsToExprVector(init->getInit())};
callParams.insert(callParams.begin(), Ref(lhsMemberExpr));
bodyStmts.AddBodyStmts(
Call(GetSpecialMemberName(stmt, GetRecordDeclType(ctorType->getAsRecordDecl())), callParams));
}
// insert our vtable pointer
InsertVtblPtr(stmt, stmt->getParent(), bodyStmts);
// in case of multi inheritance insert additional vtable pointers
for(const auto& base : parent->bases()) {
InsertVtblPtr(stmt, base.getType()->getAsCXXRecordDecl(), bodyStmts);
}
}
if(body) {
bodyStmts.AddBodyStmts(body);
}
bodyStmts.AddBodyStmts(Return(mkVarDeclRefExpr(kwInternalThis, Ptr(ctorDecl->getType()))));
body = mkCompoundStmt({bodyStmts});
retType = parentType;
// copy and move assignment op
} else if(IsCopyOrMoveAssign(stmt)) {
if(not stmt->doesThisDeclarationHaveABody() or stmt->isDefaulted()) {
// we don't want the default generated body
bodyStmts.clear();
processBaseClassesAndFields(stmt->getParent());
} else if(body) {
bodyStmts.AddBodyStmts(body);
}
bodyStmts.AddBodyStmts(Return(mkVarDeclRefExpr(kwInternalThis, Ptr(stmt->getType()))));
body = mkCompoundStmt({bodyStmts});
retType = parentType;
} else if(const auto* dtor = dyn_cast_or_null<CXXDestructorDecl>(stmt)) {
// Based on: https://www.dre.vanderbilt.edu/~schmidt/PDF/C++-translation.pdf
if(not HasDtor(GetRecordDeclType(dtor->getParent()))) {
return;
}
InsertVtblPtr(stmt, stmt->getParent(), bodyStmts);
for(const auto& base : llvm::reverse(dtor->getParent()->bases())) {
if(not dtor->isVirtual()) {
continue;
}
InsertVtblPtr(stmt, dyn_cast_or_null<CXXRecordDecl>(base.getType()->getAsRecordDecl()), bodyStmts);
}
if(body) {
bodyStmts.AddBodyStmts(body);
}
for(const auto& base : llvm::reverse(dtor->getParent()->bases())) {
if(not dtor->isVirtual()) {
continue;
}
auto* lhsDeclRef = mkVarDeclRefExpr(kwInternalThis, Ptr(base.getType()));
auto* cast = Cast(lhsDeclRef, lhsDeclRef->getType());
bodyStmts.Add(
Call(GetSpecialMemberName(stmt, GetRecordDeclType(base.getType()->getAsRecordDecl())), {cast}));
}
body = mkCompoundStmt({bodyStmts});
}
params_store params{};
params.reserve(stmt->getNumParams() + 1);
if(not IsStaticStorageClass(stmt) and not stmt->isStatic()) {
params.emplace_back(kwInternalThis, parentType);
}
for(const auto& param : stmt->parameters()) {
std::string name{GetName(*param)};
auto type = param->getType();
// at least in case of a copy constructor modify the parameters
if((0 == name.length()) and
(IsCopyOrMoveCtor(dyn_cast_or_null<CXXConstructorDecl>(stmt)) or IsCopyOrMoveAssign(stmt))) {
name = "__rhs"sv;
type = Ptr(type.getNonReferenceType());
}
params.emplace_back(name, type);
}
auto* callSpecialMemberFn = Function(GetSpecialMemberName(stmt), retType, to_params_view(params));
callSpecialMemberFn->setInlineSpecified(stmt->isInlined());
callSpecialMemberFn->setStorageClass((stmt->isStatic() or IsStaticStorageClass(stmt)) ? SC_Static : SC_None);
callSpecialMemberFn->setBody(body);
InsertArg(callSpecialMemberFn);
mOutputFormatHelper.AppendNewLine();
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::FormatCast(const std::string_view,
const QualType& castDestType,
const Expr* subExpr,
const CastKind& kind)
{
// C does not have a rvalue notation and we already transformed the temporary into an object. Skip the cast to &&.
// Ignore CK_UncheckedDerivedToBase which would lead to (A)c where neither A nor c is a pointer.
if(not castDestType->isRValueReferenceType() and not(CastKind::CK_UncheckedDerivedToBase == kind)) {
mOutputFormatHelper.Append("(", GetName(castDestType), ")");
// ARM p 221:
// C* pc = new C;
// B* pb = pc -> pc = (B*) ((char*)pc+delta(B))
if(is{kind}.any_of(CastKind::CK_DerivedToBase, CastKind::CK_BaseToDerived)) {
// We have to switch in case of a base to derived cast
auto [key,
sign] = [&]() -> std::pair<std::pair<const CXXRecordDecl*, const CXXRecordDecl*>, std::string_view> {
auto plainType = [](QualType t) {
if(const auto* pt = dyn_cast_or_null<PointerType>(t.getTypePtrOrNull())) {
return pt->getPointeeType()->getAsCXXRecordDecl();
}
return t->getAsCXXRecordDecl();
};
auto base = plainType(castDestType);
auto derived = plainType(subExpr->getType());
if((CastKind::CK_BaseToDerived == kind)) {
return {{base, derived}, "-"sv};
}
return {{derived, base}, "+"sv};
}();
if(auto off = mThisPointerOffset[key]) {
mOutputFormatHelper.Append("((char*)"sv);
InsertArg(subExpr);
mOutputFormatHelper.Append(sign, off, ")"sv);
return;
}
}
}
InsertArg(subExpr);
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::InsertArg(const CXXNullPtrLiteralExpr*)
{
EnableGlobalInsert(GlobalInserts::HeaderStddef);
mOutputFormatHelper.Append(kwNull);
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::InsertArg(const StaticAssertDecl* stmt)
{
EnableGlobalInsert(GlobalInserts::HeaderAssert);
mOutputFormatHelper.Append("_Static_assert"sv);
WrapInParens([&] {
InsertArg(stmt->getAssertExpr());
if(stmt->getMessage()) {
mOutputFormatHelper.Append(", "sv);
InsertArg(stmt->getMessage());
}
});
mOutputFormatHelper.AppendSemiNewLine();
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::InsertArg(const TypedefDecl* stmt)
{
mOutputFormatHelper.AppendSemiNewLine(kwTypedefSpace, GetName(stmt->getUnderlyingType()), " "sv, GetName(*stmt));
mOutputFormatHelper.AppendNewLine();
}
//-----------------------------------------------------------------------------
static void ProcessFields(CXXRecordDecl* recordDecl, const CXXRecordDecl* rd)
{
RETURN_IF(not rd->hasDefinition())
auto AddField = [&](const FieldDecl* field) {
recordDecl->addDecl(mkFieldDecl(recordDecl, GetName(*field), field->getType()));
};
// Insert field from base classes
for(const auto& base : rd->bases()) {
// XXX: ignoring TemplateSpecializationType
if(const auto* rdBase = dyn_cast_or_null<CXXRecordDecl>(base.getType().getCanonicalType()->getAsRecordDecl())) {
ProcessFields(recordDecl, rdBase);
}
}
// insert vtable pointer if required
if(rd->isPolymorphic() and (rd->getNumBases() == 0)) {
recordDecl->addDecl(CfrontCodeGenerator::VtableData().VtblPtrField(rd));
}
// insert own fields
for(const auto* d : rd->fields()) {
AddField(d);
}
if(recordDecl->field_empty()) {
AddField(mkFieldDecl(recordDecl, "__dummy"sv, GetGlobalAST().CharTy));
}
}
//-----------------------------------------------------------------------------
static std::string GetFirstPolymorphicBaseName(const RecordDecl* decl, const RecordDecl* to)
{
std::string ret{GetName(*decl)};
if(const auto* rdecl = dyn_cast_or_null<CXXRecordDecl>(decl); rdecl->getNumBases() > 1) {
for(const auto& base : rdecl->bases()) {
if(const auto* rd = base.getType()->getAsRecordDecl(); rd == to) {
ret += GetFirstPolymorphicBaseName(rd, to);
break;
}
}
}
return ret;
}
//-----------------------------------------------------------------------------
///! Find the first polymorphic base class.
static const CXXRecordDecl* GetFirstPolymorphicBase(const RecordDecl* decl)
{
if(const auto* rdecl = dyn_cast_or_null<CXXRecordDecl>(decl); rdecl->getNumBases() >= 1) {
for(const auto& base : rdecl->bases()) {
const auto* rd = base.getType()->getAsRecordDecl();
if(const auto* cxxRd = dyn_cast_or_null<CXXRecordDecl>(rd); not cxxRd or not cxxRd->isPolymorphic()) {
continue;
} else if(const CXXRecordDecl* ret = GetFirstPolymorphicBase(rd)) {
return ret;
}
break;
}
}
return dyn_cast_or_null<CXXRecordDecl>(decl);
}
//-----------------------------------------------------------------------------
void CfrontCodeGenerator::InsertArg(const CXXRecordDecl* stmt)
{
auto* recordDecl = Struct(GetName(*stmt));
if(stmt->hasDefinition() and stmt->isPolymorphic()) {
if(auto* itctx =
static_cast<ItaniumVTableContext*>(const_cast<ASTContext&>(GetGlobalAST()).getVTableContext())) {
#if 0
// Get mangled RTTI name
auto* mc = const_cast<ASTContext&>(GetGlobalAST()).createMangleContext(nullptr);
SmallString<256> rttiName{};
llvm::raw_svector_ostream out(rttiName);
mc->mangleCXXRTTI(QualType(stmt->getTypeForDecl(), 0), out);
DPrint("name: %s\n", rttiName.c_str());
#endif
SmallVector<Expr*, 16> mInitExprs{};
SmallVector<QualType, 5> baseList{};
if(stmt->getNumBases() == 0) {
baseList.push_back(GetRecordDeclType(stmt));
}
for(const auto& base : stmt->bases()) {
baseList.push_back(base.getType());
}
llvm::DenseMap<uint64_t, ThunkInfo> thunkMap{};
const VTableLayout& layout{itctx->getVTableLayout(stmt)};
for(const auto& [idx, thunk] : layout.vtable_thunks()) {
thunkMap[idx] = thunk;
}
unsigned clsIdx{};
unsigned funIdx{};
auto& vtblData = VtableData();
auto pushVtable = [&] {
if(funIdx) {
EnableGlobalInsert(GlobalInserts::FuncVtableStruct);
// struct __mptr __vtbl__A[] = {0, 0, 0, 0, 0, (__vptp)FunA, 0, 0, 0};
auto* thisRd = baseList[clsIdx - 1]->getAsCXXRecordDecl();
auto vtableName{StrCat("__vtbl_"sv, GetFirstPolymorphicBaseName(stmt, thisRd))};
auto* vtabl = Variable(vtableName, ContantArrayTy(vtblData.vtableRecordType, funIdx));
vtabl->setInit(InitList(mInitExprs, vtblData.vtableRecordType));
PushVtableEntry(stmt, thisRd, vtabl);
funIdx = 0;
}
mInitExprs.clear();
};
for(unsigned i = 0; const auto& vc : layout.vtable_components()) {
switch(vc.getKind()) {
case VTableComponent::CK_OffsetToTop: {
auto off = layout.getVTableOffset(clsIdx);
if(auto rem = (off % 4)) {
off += 4 - rem; // sometimes the value is misaligned. Align to 4 bytes
}
mThisPointerOffset[{stmt, baseList[clsIdx]->getAsCXXRecordDecl()}] = off * 4; // we need bytes
if(clsIdx >= 1) {
pushVtable();
}
++clsIdx;
} break;
case VTableComponent::CK_RTTI:
break;
// Source: https://itanium-cxx-abi.github.io/cxx-abi/abi.html#vtable-components
// The entries for virtual destructors are actually pairs of entries. The first destructor,
// called the complete object destructor, performs the destruction without calling delete() on
// the object. The second destructor, called the deleting destructor, calls delete() after
// destroying the object.
case VTableComponent::CK_CompleteDtorPointer:
break; // vc.getKind() == VTableComponent::CK_CompleteDtorPointer
case VTableComponent::CK_DeletingDtorPointer:
case VTableComponent::CK_FunctionPointer: {
auto* thunkOffset = [&] {
if(ThunkInfo thunk = thunkMap.lookup(i); not thunk.isEmpty() and not thunk.This.isEmpty()) {
return Int32(thunk.This.NonVirtual);
}
return Int32(0);
}();
const auto* md = dyn_cast_or_null<FunctionDecl>(vc.getFunctionDecl());
std::string name{};
if(md->isPureVirtual()) {
EnableGlobalInsert(GlobalInserts::HeaderStdlib);
EnableGlobalInsert(GlobalInserts::FuncCxaPureVirtual);
md = Function("__cxa_pure_virtual"sv, VoidTy(), params_vector{{kwInternalThis, VoidTy()}});
name = GetName(*md);
} else {
name = GetSpecialMemberName(md);
}
auto* reicast = ReinterpretCast(vtblData.vptpTypedef, mkVarDeclRefExpr(name, md->getType()));
mInitExprs.push_back(InitList({thunkOffset, Int32(0), reicast}, vtblData.vtableRecordType));
mVirtualFunctions[{md, {stmt, GetFirstPolymorphicBase(stmt)}}] = funIdx;
++funIdx;
break;