[CIR] Upstream support for calling constructors (llvm#143579)

This change adds support for calling C++ constructors. The support for
actually defining a constructor is still missing and will be added in a
later change.

Author: andykaylor

clang/include/clang/CIR/MissingFeatures.h

@@ -222,6 +222,9 @@ struct MissingFeatures {
   static bool instrumentation() { return false; }
   static bool cleanupAfterErrorDiags() { return false; }
   static bool cxxRecordStaticMembers() { return false; }
+  static bool isMemcpyEquivalentSpecialMember() { return false; }
+  static bool isTrivialCtorOrDtor() { return false; }
+  static bool implicitConstructorArgs() { return false; }
 
   // Missing types
   static bool dataMemberType() { return false; }

clang/lib/CIR/CodeGen/CIRGenCall.cpp

@@ -60,6 +60,13 @@ CIRGenCallee CIRGenCallee::prepareConcreteCallee(CIRGenFunction &cgf) const {
   return *this;
 }
 
+/// Returns the canonical formal type of the given C++ method.
+static CanQual<FunctionProtoType> getFormalType(const CXXMethodDecl *md) {
+  return md->getType()
+      ->getCanonicalTypeUnqualified()
+      .getAs<FunctionProtoType>();
+}
+
 /// Adds the formal parameters in FPT to the given prefix. If any parameter in
 /// FPT has pass_object_size_attrs, then we'll add parameters for those, too.
 /// TODO(cir): this should be shared with LLVM codegen
@@ -76,6 +83,48 @@ static void appendParameterTypes(const CIRGenTypes &cgt,
   cgt.getCGModule().errorNYI("appendParameterTypes: hasExtParameterInfos");
 }
 
+const CIRGenFunctionInfo &
+CIRGenTypes::arrangeCXXStructorDeclaration(GlobalDecl gd) {
+  auto *md = cast<CXXMethodDecl>(gd.getDecl());
+
+  llvm::SmallVector<CanQualType, 16> argTypes;
+  argTypes.push_back(deriveThisType(md->getParent(), md));
+
+  bool passParams = true;
+
+  if (auto *cd = dyn_cast<CXXConstructorDecl>(md)) {
+    // A base class inheriting constructor doesn't get forwarded arguments
+    // needed to construct a virtual base (or base class thereof)
+    if (cd->getInheritedConstructor())
+      cgm.errorNYI(cd->getSourceRange(),
+                   "arrangeCXXStructorDeclaration: inheriting constructor");
+  }
+
+  CanQual<FunctionProtoType> fpt = getFormalType(md);
+
+  if (passParams)
+    appendParameterTypes(*this, argTypes, fpt);
+
+  assert(!cir::MissingFeatures::implicitConstructorArgs());
+
+  RequiredArgs required =
+      (passParams && md->isVariadic() ? RequiredArgs(argTypes.size())
+                                      : RequiredArgs::All);
+
+  CanQualType resultType = theCXXABI.hasThisReturn(gd) ? argTypes.front()
+                           : theCXXABI.hasMostDerivedReturn(gd)
+                               ? astContext.VoidPtrTy
+                               : astContext.VoidTy;
+
+  assert(!theCXXABI.hasThisReturn(gd) &&
+         "Please send PR with a test and remove this");
+
+  assert(!cir::MissingFeatures::opCallCIRGenFuncInfoExtParamInfo());
+  assert(!cir::MissingFeatures::opCallFnInfoOpts());
+
+  return arrangeCIRFunctionInfo(resultType, argTypes, required);
+}
+
 /// Derives the 'this' type for CIRGen purposes, i.e. ignoring method CVR
 /// qualification. Either or both of `rd` and `md` may be null. A null `rd`
 /// indicates that there is no meaningful 'this' type, and a null `md` can occur
@@ -103,13 +152,13 @@ CanQualType CIRGenTypes::deriveThisType(const CXXRecordDecl *rd,
 /// top of any implicit parameters already stored.
 static const CIRGenFunctionInfo &
 arrangeCIRFunctionInfo(CIRGenTypes &cgt, SmallVectorImpl<CanQualType> &prefix,
-                       CanQual<FunctionProtoType> ftp) {
+                       CanQual<FunctionProtoType> fpt) {
   assert(!cir::MissingFeatures::opCallFnInfoOpts());
   RequiredArgs required =
-      RequiredArgs::getFromProtoWithExtraSlots(ftp, prefix.size());
+      RequiredArgs::getFromProtoWithExtraSlots(fpt, prefix.size());
   assert(!cir::MissingFeatures::opCallExtParameterInfo());
-  appendParameterTypes(cgt, prefix, ftp);
-  CanQualType resultType = ftp->getReturnType().getUnqualifiedType();
+  appendParameterTypes(cgt, prefix, fpt);
+  CanQualType resultType = fpt->getReturnType().getUnqualifiedType();
   return cgt.arrangeCIRFunctionInfo(resultType, prefix, required);
 }
 
@@ -141,6 +190,44 @@ arrangeFreeFunctionLikeCall(CIRGenTypes &cgt, CIRGenModule &cgm,
   return cgt.arrangeCIRFunctionInfo(retType, argTypes, required);
 }
 
+/// Arrange a call to a C++ method, passing the given arguments.
+///
+/// passProtoArgs indicates whether `args` has args for the parameters in the
+/// given CXXConstructorDecl.
+const CIRGenFunctionInfo &CIRGenTypes::arrangeCXXConstructorCall(
+    const CallArgList &args, const CXXConstructorDecl *d, CXXCtorType ctorKind,
+    bool passProtoArgs) {
+
+  // FIXME: Kill copy.
+  llvm::SmallVector<CanQualType, 16> argTypes;
+  for (const auto &arg : args)
+    argTypes.push_back(astContext.getCanonicalParamType(arg.ty));
+
+  assert(!cir::MissingFeatures::implicitConstructorArgs());
+  // +1 for implicit this, which should always be args[0]
+  unsigned totalPrefixArgs = 1;
+
+  CanQual<FunctionProtoType> fpt = getFormalType(d);
+  RequiredArgs required =
+      passProtoArgs
+          ? RequiredArgs::getFromProtoWithExtraSlots(fpt, totalPrefixArgs)
+          : RequiredArgs::All;
+
+  GlobalDecl gd(d, ctorKind);
+  if (theCXXABI.hasThisReturn(gd))
+    cgm.errorNYI(d->getSourceRange(),
+                 "arrangeCXXConstructorCall: hasThisReturn");
+  if (theCXXABI.hasMostDerivedReturn(gd))
+    cgm.errorNYI(d->getSourceRange(),
+                 "arrangeCXXConstructorCall: hasMostDerivedReturn");
+  CanQualType resultType = astContext.VoidTy;
+
+  assert(!cir::MissingFeatures::opCallFnInfoOpts());
+  assert(!cir::MissingFeatures::opCallCIRGenFuncInfoExtParamInfo());
+
+  return arrangeCIRFunctionInfo(resultType, argTypes, required);
+}
+
 /// Arrange a call to a C++ method, passing the given arguments.
 ///
 /// numPrefixArgs is the number of the ABI-specific prefix arguments we have. It
@@ -198,7 +285,7 @@ CIRGenTypes::arrangeCXXMethodDeclaration(const CXXMethodDecl *md) {
 /// constructor or destructor.
 const CIRGenFunctionInfo &
 CIRGenTypes::arrangeCXXMethodType(const CXXRecordDecl *rd,
-                                  const FunctionProtoType *ftp,
+                                  const FunctionProtoType *fpt,
                                   const CXXMethodDecl *md) {
   llvm::SmallVector<CanQualType, 16> argTypes;
 
@@ -208,7 +295,7 @@ CIRGenTypes::arrangeCXXMethodType(const CXXRecordDecl *rd,
   assert(!cir::MissingFeatures::opCallFnInfoOpts());
   return ::arrangeCIRFunctionInfo(
       *this, argTypes,
-      ftp->getCanonicalTypeUnqualified().getAs<FunctionProtoType>());
+      fpt->getCanonicalTypeUnqualified().getAs<FunctionProtoType>());
 }
 
 /// Arrange the argument and result information for the declaration or

clang/lib/CIR/CodeGen/CIRGenClass.cpp

@@ -10,9 +10,12 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "CIRGenCXXABI.h"
 #include "CIRGenFunction.h"
 
+#include "clang/AST/ExprCXX.h"
 #include "clang/AST/RecordLayout.h"
+#include "clang/AST/Type.h"
 #include "clang/CIR/MissingFeatures.h"
 
 using namespace clang;
@@ -63,3 +66,74 @@ Address CIRGenFunction::getAddressOfBaseClass(
 
   return value;
 }
+
+void CIRGenFunction::emitCXXConstructorCall(const clang::CXXConstructorDecl *d,
+                                            clang::CXXCtorType type,
+                                            bool forVirtualBase,
+                                            bool delegating,
+                                            AggValueSlot thisAVS,
+                                            const clang::CXXConstructExpr *e) {
+  CallArgList args;
+  Address thisAddr = thisAVS.getAddress();
+  QualType thisType = d->getThisType();
+  mlir::Value thisPtr = thisAddr.getPointer();
+
+  assert(!cir::MissingFeatures::addressSpace());
+
+  args.add(RValue::get(thisPtr), thisType);
+
+  // In LLVM Codegen: If this is a trivial constructor, just emit what's needed.
+  // If this is a union copy constructor, we must emit a memcpy, because the AST
+  // does not model that copy.
+  assert(!cir::MissingFeatures::isMemcpyEquivalentSpecialMember());
+
+  const FunctionProtoType *fpt = d->getType()->castAs<FunctionProtoType>();
+
+  assert(!cir::MissingFeatures::opCallArgEvaluationOrder());
+
+  emitCallArgs(args, fpt, e->arguments(), e->getConstructor(),
+               /*ParamsToSkip=*/0);
+
+  assert(!cir::MissingFeatures::sanitizers());
+  emitCXXConstructorCall(d, type, forVirtualBase, delegating, thisAddr, args,
+                         e->getExprLoc());
+}
+
+void CIRGenFunction::emitCXXConstructorCall(
+    const CXXConstructorDecl *d, CXXCtorType type, bool forVirtualBase,
+    bool delegating, Address thisAddr, CallArgList &args, SourceLocation loc) {
+
+  const CXXRecordDecl *crd = d->getParent();
+
+  // If this is a call to a trivial default constructor:
+  // In LLVM: do nothing.
+  // In CIR: emit as a regular call, other later passes should lower the
+  // ctor call into trivial initialization.
+  assert(!cir::MissingFeatures::isTrivialCtorOrDtor());
+
+  assert(!cir::MissingFeatures::isMemcpyEquivalentSpecialMember());
+
+  bool passPrototypeArgs = true;
+
+  // Check whether we can actually emit the constructor before trying to do so.
+  if (d->getInheritedConstructor()) {
+    cgm.errorNYI(d->getSourceRange(),
+                 "emitCXXConstructorCall: inherited constructor");
+    return;
+  }
+
+  // Insert any ABI-specific implicit constructor arguments.
+  assert(!cir::MissingFeatures::implicitConstructorArgs());
+
+  // Emit the call.
+  auto calleePtr = cgm.getAddrOfCXXStructor(GlobalDecl(d, type));
+  const CIRGenFunctionInfo &info = cgm.getTypes().arrangeCXXConstructorCall(
+      args, d, type, passPrototypeArgs);
+  CIRGenCallee callee = CIRGenCallee::forDirect(calleePtr, GlobalDecl(d, type));
+  cir::CIRCallOpInterface c;
+  emitCall(info, callee, ReturnValueSlot(), args, &c, getLoc(loc));
+
+  if (cgm.getCodeGenOpts().OptimizationLevel != 0 && !crd->isDynamicClass() &&
+      type != Ctor_Base && cgm.getCodeGenOpts().StrictVTablePointers)
+    cgm.errorNYI(d->getSourceRange(), "vtable assumption loads");
+}

clang/lib/CIR/CodeGen/CIRGenExpr.cpp

@@ -1393,6 +1393,57 @@ RValue CIRGenFunction::emitCXXMemberCallExpr(const CXXMemberCallExpr *ce,
       ce, md, returnValue, hasQualifier, qualifier, isArrow, base);
 }
 
+void CIRGenFunction::emitCXXConstructExpr(const CXXConstructExpr *e,
+                                          AggValueSlot dest) {
+  assert(!dest.isIgnored() && "Must have a destination!");
+  const CXXConstructorDecl *cd = e->getConstructor();
+
+  // If we require zero initialization before (or instead of) calling the
+  // constructor, as can be the case with a non-user-provided default
+  // constructor, emit the zero initialization now, unless destination is
+  // already zeroed.
+  if (e->requiresZeroInitialization() && !dest.isZeroed()) {
+    cgm.errorNYI(e->getSourceRange(),
+                 "emitCXXConstructExpr: requires initialization");
+    return;
+  }
+
+  // If this is a call to a trivial default constructor:
+  // In LLVM: do nothing.
+  // In CIR: emit as a regular call, other later passes should lower the
+  // ctor call into trivial initialization.
+
+  // Elide the constructor if we're constructing from a temporary
+  if (getLangOpts().ElideConstructors && e->isElidable()) {
+    cgm.errorNYI(e->getSourceRange(),
+                 "emitCXXConstructExpr: elidable constructor");
+    return;
+  }
+
+  if (getContext().getAsArrayType(e->getType())) {
+    cgm.errorNYI(e->getSourceRange(), "emitCXXConstructExpr: array type");
+    return;
+  }
+
+  clang::CXXCtorType type = Ctor_Complete;
+  bool forVirtualBase = false;
+  bool delegating = false;
+
+  switch (e->getConstructionKind()) {
+  case CXXConstructionKind::Complete:
+    type = Ctor_Complete;
+    break;
+  case CXXConstructionKind::Delegating:
+  case CXXConstructionKind::VirtualBase:
+  case CXXConstructionKind::NonVirtualBase:
+    cgm.errorNYI(e->getSourceRange(),
+                 "emitCXXConstructExpr: other construction kind");
+    return;
+  }
+
+  emitCXXConstructorCall(cd, type, forVirtualBase, delegating, dest, e);
+}
+
 RValue CIRGenFunction::emitReferenceBindingToExpr(const Expr *e) {
   // Emit the expression as an lvalue.
   LValue lv = emitLValue(e);

clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp

@@ -51,6 +51,7 @@ class AggExprEmitter : public StmtVisitor<AggExprEmitter> {
   void Visit(Expr *e) { StmtVisitor<AggExprEmitter>::Visit(e); }
 
   void VisitInitListExpr(InitListExpr *e);
+  void VisitCXXConstructExpr(const CXXConstructExpr *e);
 
   void visitCXXParenListOrInitListExpr(Expr *e, ArrayRef<Expr *> args,
                                        FieldDecl *initializedFieldInUnion,
@@ -213,6 +214,11 @@ void AggExprEmitter::emitInitializationToLValue(Expr *e, LValue lv) {
   }
 }
 
+void AggExprEmitter::VisitCXXConstructExpr(const CXXConstructExpr *e) {
+  AggValueSlot slot = ensureSlot(cgf.getLoc(e->getSourceRange()), e->getType());
+  cgf.emitCXXConstructExpr(e, slot);
+}
+
 void AggExprEmitter::emitNullInitializationToLValue(mlir::Location loc,
                                                     LValue lv) {
   const QualType type = lv.getType();

clang/lib/CIR/CodeGen/CIRGenFunction.h

@@ -744,6 +744,19 @@ class CIRGenFunction : public CIRGenTypeCache {
 
   mlir::LogicalResult emitContinueStmt(const clang::ContinueStmt &s);
 
+  void emitCXXConstructExpr(const clang::CXXConstructExpr *e,
+                            AggValueSlot dest);
+
+  void emitCXXConstructorCall(const clang::CXXConstructorDecl *d,
+                              clang::CXXCtorType type, bool forVirtualBase,
+                              bool delegating, AggValueSlot thisAVS,
+                              const clang::CXXConstructExpr *e);
+
+  void emitCXXConstructorCall(const clang::CXXConstructorDecl *d,
+                              clang::CXXCtorType type, bool forVirtualBase,
+                              bool delegating, Address thisAddr,
+                              CallArgList &args, clang::SourceLocation loc);
+
   mlir::LogicalResult emitCXXForRangeStmt(const CXXForRangeStmt &s,
                                           llvm::ArrayRef<const Attr *> attrs);