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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ART_COMPILER_OPTIMIZING_INTRINSICS_UTILS_H_
     18 #define ART_COMPILER_OPTIMIZING_INTRINSICS_UTILS_H_
     19 
     20 #include "base/macros.h"
     21 #include "code_generator.h"
     22 #include "locations.h"
     23 #include "nodes.h"
     24 #include "utils/assembler.h"
     25 #include "utils/label.h"
     26 
     27 namespace art {
     28 
     29 // Default slow-path for fallback (calling the managed code to handle the intrinsic) in an
     30 // intrinsified call. This will copy the arguments into the positions for a regular call.
     31 //
     32 // Note: The actual parameters are required to be in the locations given by the invoke's location
     33 //       summary. If an intrinsic modifies those locations before a slowpath call, they must be
     34 //       restored!
     35 //
     36 // Note: If an invoke wasn't sharpened, we will put down an invoke-virtual here. That's potentially
     37 //       sub-optimal (compared to a direct pointer call), but this is a slow-path.
     38 
     39 template <typename TDexCallingConvention>
     40 class IntrinsicSlowPath : public SlowPathCode {
     41  public:
     42   explicit IntrinsicSlowPath(HInvoke* invoke) : SlowPathCode(invoke), invoke_(invoke) { }
     43 
     44   Location MoveArguments(CodeGenerator* codegen) {
     45     TDexCallingConvention calling_convention_visitor;
     46     IntrinsicVisitor::MoveArguments(invoke_, codegen, &calling_convention_visitor);
     47     return calling_convention_visitor.GetMethodLocation();
     48   }
     49 
     50   void EmitNativeCode(CodeGenerator* codegen) OVERRIDE {
     51     Assembler* assembler = codegen->GetAssembler();
     52     assembler->Bind(GetEntryLabel());
     53 
     54     SaveLiveRegisters(codegen, invoke_->GetLocations());
     55 
     56     Location method_loc = MoveArguments(codegen);
     57 
     58     if (invoke_->IsInvokeStaticOrDirect()) {
     59       codegen->GenerateStaticOrDirectCall(invoke_->AsInvokeStaticOrDirect(), method_loc, this);
     60     } else {
     61       codegen->GenerateVirtualCall(invoke_->AsInvokeVirtual(), method_loc, this);
     62     }
     63 
     64     // Copy the result back to the expected output.
     65     Location out = invoke_->GetLocations()->Out();
     66     if (out.IsValid()) {
     67       DCHECK(out.IsRegister());  // TODO: Replace this when we support output in memory.
     68       DCHECK(!invoke_->GetLocations()->GetLiveRegisters()->ContainsCoreRegister(out.reg()));
     69       codegen->MoveFromReturnRegister(out, invoke_->GetType());
     70     }
     71 
     72     RestoreLiveRegisters(codegen, invoke_->GetLocations());
     73     assembler->Jump(GetExitLabel());
     74   }
     75 
     76   const char* GetDescription() const OVERRIDE { return "IntrinsicSlowPath"; }
     77 
     78  private:
     79   // The instruction where this slow path is happening.
     80   HInvoke* const invoke_;
     81 
     82   DISALLOW_COPY_AND_ASSIGN(IntrinsicSlowPath);
     83 };
     84 
     85 }  // namespace art
     86 
     87 #endif  // ART_COMPILER_OPTIMIZING_INTRINSICS_UTILS_H_
     88