[CodeGen] Fix ExtParameterInfo bugs in C++ CodeGen code.

This patch makes use of the prefix/suffix ABI argument distinction that
was introduced in r295870, so that we now emit ExtParameterInfo at the
correct offset for member calls that have added ABI arguments. I don't
see a good way to test the generated param info, since we don't actually
seem to use it in CGFunctionInfo outside of Swift. Any
suggestions/thoughts for how to better test this are welcome. :)

This patch also fixes a small bug with inheriting constructors: if we
decide not to pass args into an base class ctor, we would still
generate ExtParameterInfo as though we did. The added test-case is for
that behavior.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@296024 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGCall.cpp

@@ -362,18 +362,31 @@ getExtParameterInfosForCall(const FunctionProtoType *proto,
 }
 
 /// Arrange a call to a C++ method, passing the given arguments.
+///
+/// ExtraPrefixArgs is the number of ABI-specific args passed after the `this`
+/// parameter.
+/// ExtraSuffixArgs is the number of ABI-specific args passed at the end of
+/// args.
+/// PassProtoArgs indicates whether `args` has args for the parameters in the
+/// given CXXConstructorDecl.
 const CGFunctionInfo &
 CodeGenTypes::arrangeCXXConstructorCall(const CallArgList &args,
                                         const CXXConstructorDecl *D,
                                         CXXCtorType CtorKind,
-                                        unsigned ExtraArgs) {
+                                        unsigned ExtraPrefixArgs,
+                                        unsigned ExtraSuffixArgs,
+                                        bool PassProtoArgs) {
   // FIXME: Kill copy.
   SmallVector<CanQualType, 16> ArgTypes;
   for (const auto &Arg : args)
     ArgTypes.push_back(Context.getCanonicalParamType(Arg.Ty));
 
+  // +1 for implicit this, which should always be args[0].
+  unsigned TotalPrefixArgs = 1 + ExtraPrefixArgs;
+
   CanQual<FunctionProtoType> FPT = GetFormalType(D);
-  RequiredArgs Required = RequiredArgs::forPrototypePlus(FPT, 1 + ExtraArgs, D);
+  RequiredArgs Required =
+      RequiredArgs::forPrototypePlus(FPT, TotalPrefixArgs + ExtraSuffixArgs, D);
   GlobalDecl GD(D, CtorKind);
   CanQualType ResultType = TheCXXABI.HasThisReturn(GD)
                                ? ArgTypes.front()
@@ -382,8 +395,14 @@ CodeGenTypes::arrangeCXXConstructorCall(const CallArgList &args,
                                      : Context.VoidTy;
 
   FunctionType::ExtInfo Info = FPT->getExtInfo();
-  auto ParamInfos = getExtParameterInfosForCall(FPT.getTypePtr(), 1 + ExtraArgs,
-                                                ArgTypes.size());
+  llvm::SmallVector<FunctionProtoType::ExtParameterInfo, 16> ParamInfos;
+  // If the prototype args are elided, we should only have ABI-specific args,
+  // which never have param info.
+  if (PassProtoArgs && FPT->hasExtParameterInfos()) {
+    // ABI-specific suffix arguments are treated the same as variadic arguments.
+    addExtParameterInfosForCall(ParamInfos, FPT.getTypePtr(), TotalPrefixArgs,
+                                ArgTypes.size());
+  }
   return arrangeLLVMFunctionInfo(ResultType, /*instanceMethod=*/true,
                                  /*chainCall=*/false, ArgTypes, Info,
                                  ParamInfos, Required);
@@ -627,15 +646,20 @@ CodeGenTypes::arrangeBuiltinFunctionDeclaration(CanQualType resultType,
 }
 
 /// Arrange a call to a C++ method, passing the given arguments.
+///
+/// numPrefixArgs is the number of ABI-specific prefix arguments we have. It
+/// does not count `this`.
 const CGFunctionInfo &
 CodeGenTypes::arrangeCXXMethodCall(const CallArgList &args,
                                    const FunctionProtoType *proto,
-                                   RequiredArgs required) {
-  unsigned numRequiredArgs =
-    (proto->isVariadic() ? required.getNumRequiredArgs() : args.size());
-  unsigned numPrefixArgs = numRequiredArgs - proto->getNumParams();
+                                   RequiredArgs required,
+                                   unsigned numPrefixArgs) {
+  assert(numPrefixArgs + 1 <= args.size() &&
+         "Emitting a call with less args than the required prefix?");
+  // Add one to account for `this`. It's a bit awkward here, but we don't count
+  // `this` in similar places elsewhere.
   auto paramInfos =
-    getExtParameterInfosForCall(proto, numPrefixArgs, args.size());
+    getExtParameterInfosForCall(proto, numPrefixArgs + 1, args.size());
 
   // FIXME: Kill copy.
   auto argTypes = getArgTypesForCall(Context, args);

lib/CodeGen/CGClass.cpp

@@ -1979,7 +1979,7 @@ static bool canEmitDelegateCallArgs(CodeGenFunction &CGF,
 
     // Likewise if they're inalloca.
     const CGFunctionInfo &Info =
-        CGF.CGM.getTypes().arrangeCXXConstructorCall(Args, Ctor, Type, 0);
+        CGF.CGM.getTypes().arrangeCXXConstructorCall(Args, Ctor, Type, 0, 0);
     if (Info.usesInAlloca())
       return false;
   }
@@ -2021,10 +2021,11 @@ void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
     return;
   }
 
+  bool PassPrototypeArgs = true;
   // Check whether we can actually emit the constructor before trying to do so.
   if (auto Inherited = D->getInheritedConstructor()) {
-    if (getTypes().inheritingCtorHasParams(Inherited, Type) &&
-        !canEmitDelegateCallArgs(*this, D, Type, Args)) {
+    PassPrototypeArgs = getTypes().inheritingCtorHasParams(Inherited, Type);
+    if (PassPrototypeArgs && !canEmitDelegateCallArgs(*this, D, Type, Args)) {
       EmitInlinedInheritingCXXConstructorCall(D, Type, ForVirtualBase,
                                               Delegating, Args);
       return;
@@ -2040,7 +2041,7 @@ void CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
   llvm::Constant *CalleePtr =
     CGM.getAddrOfCXXStructor(D, getFromCtorType(Type));
   const CGFunctionInfo &Info = CGM.getTypes().arrangeCXXConstructorCall(
-      Args, D, Type, ExtraArgs.Prefix + ExtraArgs.Suffix);
+      Args, D, Type, ExtraArgs.Prefix, ExtraArgs.Suffix, PassPrototypeArgs);
   CGCallee Callee = CGCallee::forDirect(CalleePtr, D);
   EmitCall(Info, Callee, ReturnValueSlot(), Args);
 

lib/CodeGen/CGExprCXX.cpp

@@ -24,7 +24,15 @@
 using namespace clang;
 using namespace CodeGen;
 
-static RequiredArgs
+namespace {
+struct MemberCallInfo {
+  RequiredArgs ReqArgs;
+  // Number of prefix arguments for the call. Ignores the `this` pointer.
+  unsigned PrefixSize;
+};
+}
+
+static MemberCallInfo
 commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, const CXXMethodDecl *MD,
                                   llvm::Value *This, llvm::Value *ImplicitParam,
                                   QualType ImplicitParamTy, const CallExpr *CE,
@@ -48,6 +56,7 @@ commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, const CXXMethodDecl *MD,
 
   const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
   RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size(), MD);
+  unsigned PrefixSize = Args.size() - 1;
 
   // And the rest of the call args.
   if (RtlArgs) {
@@ -65,7 +74,7 @@ commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, const CXXMethodDecl *MD,
         FPT->getNumParams() == 0 &&
         "No CallExpr specified for function with non-zero number of arguments");
   }
-  return required;
+  return {required, PrefixSize};
 }
 
 RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
@@ -75,9 +84,10 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
     const CallExpr *CE, CallArgList *RtlArgs) {
   const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
   CallArgList Args;
-  RequiredArgs required = commonEmitCXXMemberOrOperatorCall(
+  MemberCallInfo CallInfo = commonEmitCXXMemberOrOperatorCall(
       *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args, RtlArgs);
-  auto &FnInfo = CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required);
+  auto &FnInfo = CGM.getTypes().arrangeCXXMethodCall(
+      Args, FPT, CallInfo.ReqArgs, CallInfo.PrefixSize);
   return EmitCall(FnInfo, Callee, ReturnValue, Args);
 }
 
@@ -425,7 +435,8 @@ CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
 
   // And the rest of the call args
   EmitCallArgs(Args, FPT, E->arguments());
-  return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required),
+  return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required,
+                                                      /*PrefixSize=*/0),
                   Callee, ReturnValue, Args);
 }
 

lib/CodeGen/CGVTables.cpp

@@ -284,6 +284,7 @@ void CodeGenFunction::EmitCallAndReturnForThunk(llvm::Constant *CalleePtr,
   if (isa<CXXDestructorDecl>(MD))
     CGM.getCXXABI().adjustCallArgsForDestructorThunk(*this, CurGD, CallArgs);
 
+  unsigned PrefixArgs = CallArgs.size() - 1;
   // Add the rest of the arguments.
   for (const ParmVarDecl *PD : MD->parameters())
     EmitDelegateCallArg(CallArgs, PD, SourceLocation());
@@ -292,7 +293,7 @@ void CodeGenFunction::EmitCallAndReturnForThunk(llvm::Constant *CalleePtr,
 
 #ifndef NDEBUG
   const CGFunctionInfo &CallFnInfo = CGM.getTypes().arrangeCXXMethodCall(
-      CallArgs, FPT, RequiredArgs::forPrototypePlus(FPT, 1, MD));
+      CallArgs, FPT, RequiredArgs::forPrototypePlus(FPT, 1, MD), PrefixArgs);
   assert(CallFnInfo.getRegParm() == CurFnInfo->getRegParm() &&
          CallFnInfo.isNoReturn() == CurFnInfo->isNoReturn() &&
          CallFnInfo.getCallingConvention() == CurFnInfo->getCallingConvention());

lib/CodeGen/CodeGenTypes.h

@@ -303,11 +303,14 @@ public:
   const CGFunctionInfo &arrangeCXXConstructorCall(const CallArgList &Args,
                                                   const CXXConstructorDecl *D,
                                                   CXXCtorType CtorKind,
-                                                  unsigned ExtraArgs);
+                                                  unsigned ExtraPrefixArgs,
+                                                  unsigned ExtraSuffixArgs,
+                                                  bool PassProtoArgs = true);
 
   const CGFunctionInfo &arrangeCXXMethodCall(const CallArgList &args,
                                              const FunctionProtoType *type,
-                                             RequiredArgs required);
+                                             RequiredArgs required,
+                                             unsigned numPrefixArgs);
   const CGFunctionInfo &arrangeMSMemberPointerThunk(const CXXMethodDecl *MD);
   const CGFunctionInfo &arrangeMSCtorClosure(const CXXConstructorDecl *CD,
                                                  CXXCtorType CT);

lib/CodeGen/MicrosoftCXXABI.cpp

@@ -3934,7 +3934,7 @@ MicrosoftCXXABI::getAddrOfCXXCtorClosure(const CXXConstructorDecl *CD,
     CGM.getAddrOfCXXStructor(CD, StructorType::Complete);
   CGCallee Callee = CGCallee::forDirect(CalleePtr, CD);
   const CGFunctionInfo &CalleeInfo = CGM.getTypes().arrangeCXXConstructorCall(
-      Args, CD, Ctor_Complete, ExtraArgs.Prefix + ExtraArgs.Suffix);
+      Args, CD, Ctor_Complete, ExtraArgs.Prefix, ExtraArgs.Suffix);
   CGF.EmitCall(CalleeInfo, Callee, ReturnValueSlot(), Args);
 
   Cleanups.ForceCleanup();

test/CodeGenObjCXX/arc-attrs-abi.mm

@@ -1,8 +1,8 @@
-// RUN: %clang_cc1 -triple x86_64-apple -emit-llvm -fobjc-arc -o - %s
-// RUN: %clang_cc1 -triple x86_64-windows -emit-llvm -fobjc-arc -o - %s
+// RUN: %clang_cc1 -triple x86_64-apple -emit-llvm -fobjc-arc -o - %s -std=c++11 | FileCheck %s --check-prefix=ITANIUM
+// RUN: %clang_cc1 -triple x86_64-windows -emit-llvm -fobjc-arc -o - %s -std=c++11
 //
-// Test caess where we weren't properly adding parameter infos declarations,
-// which caused assertions to fire. Hence, no CHECKs.
+// Test cases where we weren't properly adding extended parameter info, which
+// caused assertions to fire. Hence, minimal CHECKs.
 
 struct VirtualBase {
   VirtualBase(__attribute__((ns_consumed)) id x);
@@ -13,3 +13,25 @@ struct WithVirtualBase : virtual VirtualBase {
 
 WithVirtualBase::WithVirtualBase(__attribute__((ns_consumed)) id x)
     : VirtualBase(x) {}
+
+
+struct VirtualBase2 {
+  VirtualBase2(__attribute__((ns_consumed)) id x, void *y);
+};
+
+// In this case, we don't actually end up passing the `id` param from
+// WithVirtualBaseLast's ctor to WithVirtualBaseMid's. So, we shouldn't emit
+// ext param info for `id` to `Mid`. Itanium-only check since MSABI seems to
+// emit the construction code inline.
+struct WithVirtualBaseMid : virtual VirtualBase2 {
+  // Ensure we only pass in `this` and a vtable. Otherwise this test is useless.
+  // ITANIUM: define {{.*}} void @_ZN18WithVirtualBaseMidCI212VirtualBase2EP11objc_objectPv({{.*}}, {{.*}})
+  using VirtualBase2::VirtualBase2;
+};
+struct WithVirtualBaseLast : WithVirtualBaseMid {
+  using WithVirtualBaseMid::WithVirtualBaseMid;
+};
+
+void callLast(__attribute__((ns_consumed)) id x) {
+  WithVirtualBaseLast{x, (void*)0};
+}