From 23f6626262895d5307e2398e3377dc38c978ea43 Mon Sep 17 00:00:00 2001
From: John McCall <rjmccall@apple.com>
Date: Wed, 26 May 2010 22:34:26 +0000
Subject: Correctly pass aggregates by reference when emitting thunks.

llvm-svn: 104778
---
 clang/lib/CodeGen/CGCall.cpp | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

(limited to 'clang/lib/CodeGen/CGCall.cpp')

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 0d6a70c64d4..73cee3c10d2 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -862,6 +862,36 @@ void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI,
   }
 }
 
+RValue CodeGenFunction::EmitDelegateCallArg(const VarDecl *Param) {
+  // StartFunction converted the ABI-lowered parameter(s) into a
+  // local alloca.  We need to turn that into an r-value suitable
+  // for EmitCall.
+  llvm::Value *Local = GetAddrOfLocalVar(Param);
+
+  QualType ArgType = Param->getType();
+ 
+  // For the most part, we just need to load the alloca, except:
+  // 1) aggregate r-values are actually pointers to temporaries, and
+  // 2) references to aggregates are pointers directly to the aggregate.
+  // I don't know why references to non-aggregates are different here.
+  if (const ReferenceType *RefType = ArgType->getAs<ReferenceType>()) {
+    if (hasAggregateLLVMType(RefType->getPointeeType()))
+      return RValue::getAggregate(Local);
+
+    // Locals which are references to scalars are represented
+    // with allocas holding the pointer.
+    return RValue::get(Builder.CreateLoad(Local));
+  }
+
+  if (ArgType->isAnyComplexType())
+    return RValue::getComplex(LoadComplexFromAddr(Local, /*volatile*/ false));
+
+  if (hasAggregateLLVMType(ArgType))
+    return RValue::getAggregate(Local);
+
+  return RValue::get(EmitLoadOfScalar(Local, false, ArgType));
+}
+
 RValue CodeGenFunction::EmitCallArg(const Expr *E, QualType ArgType) {
   if (ArgType->isReferenceType())
     return EmitReferenceBindingToExpr(E);
-- 
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