[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.

llvm-svn: 296024

1 files changed, 16 insertions, 5 deletions

diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 29c307bbef8..e597f469052 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/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);
 }