1 files changed, 190 insertions, 17 deletions

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index d2fcbea..44647a6 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -7378,38 +7378,147 @@ public:
 namespace {
 
 class AMDGPUABIInfo final : public DefaultABIInfo {
+private:
+  static const unsigned MaxNumRegsForArgsRet = 16;
+
+  bool shouldReturnTypeInRegister(QualType Ty,
+                                  ASTContext &Context) const;
+  unsigned numRegsForType(QualType Ty) const;
+
+  bool isHomogeneousAggregateBaseType(QualType Ty) const override;
+  bool isHomogeneousAggregateSmallEnough(const Type *Base,
+                                         uint64_t Members) const override;
+
 public:
-  explicit AMDGPUABIInfo(CodeGen::CodeGenTypes &CGT) : DefaultABIInfo(CGT) {}
+  explicit AMDGPUABIInfo(CodeGen::CodeGenTypes &CGT) :
+    DefaultABIInfo(CGT) {}
 
-private:
-  ABIArgInfo classifyArgumentType(QualType Ty) const;
+  ABIArgInfo classifyReturnType(QualType RetTy) const;
+  ABIArgInfo classifyKernelArgumentType(QualType Ty) const;
+  ABIArgInfo classifyArgumentType(QualType Ty, unsigned &NumRegsLeft) const;
 
   void computeInfo(CGFunctionInfo &FI) const override;
 };
 
+bool AMDGPUABIInfo::isHomogeneousAggregateBaseType(QualType Ty) const {
+  return true;
+}
+
+bool AMDGPUABIInfo::isHomogeneousAggregateSmallEnough(
+  const Type *Base, uint64_t Members) const {
+  uint32_t NumRegs = (getContext().getTypeSize(Base) + 31) / 32;
+
+  // Homogeneous Aggregates may occupy at most 16 registers.
+  return Members * NumRegs <= MaxNumRegsForArgsRet;
+}
+
+/// Check whether the type is small enough to consider passing directly in
+/// registers.
+bool AMDGPUABIInfo::shouldReturnTypeInRegister(QualType Ty,
+                                               ASTContext &Ctx) const {
+  return ((Ctx.getTypeSize(Ty) + 31) / 32) <= MaxNumRegsForArgsRet;
+}
+
+/// Estimate number of registers the type will use when passed in registers.
+unsigned AMDGPUABIInfo::numRegsForType(QualType Ty) const {
+  unsigned NumRegs = 0;
+
+  if (const VectorType *VT = Ty->getAs<VectorType>()) {
+    // Compute from the number of elements. The reported size is based on the
+    // in-memory size, which includes the padding 4th element for 3-vectors.
+    QualType EltTy = VT->getElementType();
+    unsigned EltSize = getContext().getTypeSize(EltTy);
+
+    // 16-bit element vectors should be passed as packed.
+    if (EltSize == 16)
+      return (VT->getNumElements() + 1) / 2;
+
+    unsigned EltNumRegs = (EltSize + 31) / 32;
+    return EltNumRegs * VT->getNumElements();
+  }
+
+  if (const RecordType *RT = Ty->getAs<RecordType>()) {
+    const RecordDecl *RD = RT->getDecl();
+    assert(!RD->hasFlexibleArrayMember());
+
+    for (const FieldDecl *Field : RD->fields()) {
+      QualType FieldTy = Field->getType();
+      NumRegs += numRegsForType(FieldTy);
+    }
+
+    return NumRegs;
+  }
+
+  return (getContext().getTypeSize(Ty) + 31) / 32;
+}
+
 void AMDGPUABIInfo::computeInfo(CGFunctionInfo &FI) const {
+  llvm::CallingConv::ID CC = FI.getCallingConvention();
+
   if (!getCXXABI().classifyReturnType(FI))
     FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
 
-  unsigned CC = FI.getCallingConvention();
-  for (auto &Arg : FI.arguments())
-    if (CC == llvm::CallingConv::AMDGPU_KERNEL)
-      Arg.info = classifyArgumentType(Arg.type);
-    else
-      Arg.info = DefaultABIInfo::classifyArgumentType(Arg.type);
+  unsigned NumRegsLeft = MaxNumRegsForArgsRet;
+  for (auto &Arg : FI.arguments()) {
+    if (CC == llvm::CallingConv::AMDGPU_KERNEL) {
+      Arg.info = classifyKernelArgumentType(Arg.type);
+    } else {
+      Arg.info = classifyArgumentType(Arg.type, NumRegsLeft);
+    }
+  }
 }
 
-/// \brief Classify argument of given type \p Ty.
-ABIArgInfo AMDGPUABIInfo::classifyArgumentType(QualType Ty) const {
-  llvm::StructType *StrTy = dyn_cast<llvm::StructType>(CGT.ConvertType(Ty));
-  if (!StrTy) {
-    return DefaultABIInfo::classifyArgumentType(Ty);
+ABIArgInfo AMDGPUABIInfo::classifyReturnType(QualType RetTy) const {
+  if (isAggregateTypeForABI(RetTy)) {
+    // Records with non-trivial destructors/copy-constructors should not be
+    // returned by value.
+    if (!getRecordArgABI(RetTy, getCXXABI())) {
+      // Ignore empty structs/unions.
+      if (isEmptyRecord(getContext(), RetTy, true))
+        return ABIArgInfo::getIgnore();
+
+      // Lower single-element structs to just return a regular value.
+      if (const Type *SeltTy = isSingleElementStruct(RetTy, getContext()))
+        return ABIArgInfo::getDirect(CGT.ConvertType(QualType(SeltTy, 0)));
+
+      if (const RecordType *RT = RetTy->getAs<RecordType>()) {
+        const RecordDecl *RD = RT->getDecl();
+        if (RD->hasFlexibleArrayMember())
+          return DefaultABIInfo::classifyReturnType(RetTy);
+      }
+
+      // Pack aggregates <= 4 bytes into single VGPR or pair.
+      uint64_t Size = getContext().getTypeSize(RetTy);
+      if (Size <= 16)
+        return ABIArgInfo::getDirect(llvm::Type::getInt16Ty(getVMContext()));
+
+      if (Size <= 32)
+        return ABIArgInfo::getDirect(llvm::Type::getInt32Ty(getVMContext()));
+
+      if (Size <= 64) {
+        llvm::Type *I32Ty = llvm::Type::getInt32Ty(getVMContext());
+        return ABIArgInfo::getDirect(llvm::ArrayType::get(I32Ty, 2));
+      }
+
+      if (numRegsForType(RetTy) <= MaxNumRegsForArgsRet)
+        return ABIArgInfo::getDirect();
+    }
   }
 
+  // Otherwise just do the default thing.
+  return DefaultABIInfo::classifyReturnType(RetTy);
+}
+
+/// For kernels all parameters are really passed in a special buffer. It doesn't
+/// make sense to pass anything byval, so everything must be direct.
+ABIArgInfo AMDGPUABIInfo::classifyKernelArgumentType(QualType Ty) const {
+  Ty = useFirstFieldIfTransparentUnion(Ty);
+
+  // TODO: Can we omit empty structs?
+
   // Coerce single element structs to its element.
-  if (StrTy->getNumElements() == 1) {
-    return ABIArgInfo::getDirect();
-  }
+  if (const Type *SeltTy = isSingleElementStruct(Ty, getContext()))
+    return ABIArgInfo::getDirect(CGT.ConvertType(QualType(SeltTy, 0)));
 
   // If we set CanBeFlattened to true, CodeGen will expand the struct to its
   // individual elements, which confuses the Clover OpenCL backend; therefore we
@@ -7417,6 +7526,70 @@ ABIArgInfo AMDGPUABIInfo::classifyArgumentType(QualType Ty) const {
   return ABIArgInfo::getDirect(nullptr, 0, nullptr, false);
 }
 
+ABIArgInfo AMDGPUABIInfo::classifyArgumentType(QualType Ty,
+                                               unsigned &NumRegsLeft) const {
+  assert(NumRegsLeft <= MaxNumRegsForArgsRet && "register estimate underflow");
+
+  Ty = useFirstFieldIfTransparentUnion(Ty);
+
+  if (isAggregateTypeForABI(Ty)) {
+    // Records with non-trivial destructors/copy-constructors should not be
+    // passed by value.
+    if (auto RAA = getRecordArgABI(Ty, getCXXABI()))
+      return getNaturalAlignIndirect(Ty, RAA == CGCXXABI::RAA_DirectInMemory);
+
+    // Ignore empty structs/unions.
+    if (isEmptyRecord(getContext(), Ty, true))
+      return ABIArgInfo::getIgnore();
+
+    // Lower single-element structs to just pass a regular value. TODO: We
+    // could do reasonable-size multiple-element structs too, using getExpand(),
+    // though watch out for things like bitfields.
+    if (const Type *SeltTy = isSingleElementStruct(Ty, getContext()))
+      return ABIArgInfo::getDirect(CGT.ConvertType(QualType(SeltTy, 0)));
+
+    if (const RecordType *RT = Ty->getAs<RecordType>()) {
+      const RecordDecl *RD = RT->getDecl();
+      if (RD->hasFlexibleArrayMember())
+        return DefaultABIInfo::classifyArgumentType(Ty);
+    }
+
+    // Pack aggregates <= 8 bytes into single VGPR or pair.
+    uint64_t Size = getContext().getTypeSize(Ty);
+    if (Size <= 64) {
+      unsigned NumRegs = (Size + 31) / 32;
+      NumRegsLeft -= std::min(NumRegsLeft, NumRegs);
+
+      if (Size <= 16)
+        return ABIArgInfo::getDirect(llvm::Type::getInt16Ty(getVMContext()));
+
+      if (Size <= 32)
+        return ABIArgInfo::getDirect(llvm::Type::getInt32Ty(getVMContext()));
+
+      // XXX: Should this be i64 instead, and should the limit increase?
+      llvm::Type *I32Ty = llvm::Type::getInt32Ty(getVMContext());
+      return ABIArgInfo::getDirect(llvm::ArrayType::get(I32Ty, 2));
+    }
+
+    if (NumRegsLeft > 0) {
+      unsigned NumRegs = numRegsForType(Ty);
+      if (NumRegsLeft >= NumRegs) {
+        NumRegsLeft -= NumRegs;
+        return ABIArgInfo::getDirect();
+      }
+    }
+  }
+
+  // Otherwise just do the default thing.
+  ABIArgInfo ArgInfo = DefaultABIInfo::classifyArgumentType(Ty);
+  if (!ArgInfo.isIndirect()) {
+    unsigned NumRegs = numRegsForType(Ty);
+    NumRegsLeft -= std::min(NumRegs, NumRegsLeft);
+  }
+
+  return ArgInfo;
+}
+
 class AMDGPUTargetCodeGenInfo : public TargetCodeGenInfo {
 public:
   AMDGPUTargetCodeGenInfo(CodeGenTypes &CGT)