AMDGPUResourceUsageAnalysis.h

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//===- AMDGPUResourceUsageAnalysis.h ---- analysis of resources -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
/// \file
/// \brief Analyzes how many registers and other resources are used by
/// functions.
///
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_LIB_TARGET_AMDGPU_AMDGPURESOURCEUSAGEANALYSIS_H
#define LLVM_LIB_TARGET_AMDGPU_AMDGPURESOURCEUSAGEANALYSIS_H
 
#include "llvm/Analysis/CallGraphSCCPass.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
 
namespace llvm {
 
class GCNSubtarget;
class MachineFunction;
class TargetMachine;
 
struct AMDGPUResourceUsageAnalysis : public ModulePass {
  static char ID;
 
public:
  // Track resource usage for callee functions.
  struct SIFunctionResourceInfo {
    // Track the number of explicitly used VGPRs. Special registers reserved at
    // the end are tracked separately.
    int32_t NumVGPR = 0;
    int32_t NumAGPR = 0;
    int32_t NumExplicitSGPR = 0;
    uint64_t PrivateSegmentSize = 0;
    bool UsesVCC = false;
    bool UsesFlatScratch = false;
    bool HasDynamicallySizedStack = false;
    bool HasRecursion = false;
    bool HasIndirectCall = false;
 
    int32_t getTotalNumSGPRs(const GCNSubtarget &ST) const;
    // Total number of VGPRs is actually a combination of AGPR and VGPR
    // depending on architecture - and some alignment constraints
    int32_t getTotalNumVGPRs(const GCNSubtarget &ST, int32_t NumAGPR,
                             int32_t NumVGPR) const;
    int32_t getTotalNumVGPRs(const GCNSubtarget &ST) const;
  };
 
  AMDGPUResourceUsageAnalysis() : ModulePass(ID) {}
 
  bool doInitialization(Module &M) override {
    CallGraphResourceInfo.clear();
    return ModulePass::doInitialization(M);
  }
 
  bool runOnModule(Module &M) override;
 
  void getAnalysisUsage(AnalysisUsage &AU) const override {
    AU.addRequired<MachineModuleInfoWrapperPass>();
    AU.setPreservesAll();
  }
 
  const SIFunctionResourceInfo &getResourceInfo(const Function *F) const {
    auto Info = CallGraphResourceInfo.find(F);
    assert(Info != CallGraphResourceInfo.end() &&
           "Failed to find resource info for function");
    return Info->getSecond();
  }
 
private:
  SIFunctionResourceInfo analyzeResourceUsage(const MachineFunction &MF,
                                              const TargetMachine &TM) const;
  void propagateIndirectCallRegisterUsage();
 
  DenseMap<const Function *, SIFunctionResourceInfo> CallGraphResourceInfo;
};
} // namespace llvm
#endif // LLVM_LIB_TARGET_AMDGPU_AMDGPURESOURCEUSAGEANALYSIS_H