tools/llvm-exegesis/lib/SnippetGenerator.h

   1 //===-- SnippetGenerator.h --------------------------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 ///
  10 /// \file
  11 /// Defines the abstract SnippetGenerator class for generating code that allows
  12 /// measuring a certain property of instructions (e.g. latency).
  13 ///
  14 //===----------------------------------------------------------------------===//
  15
  16 #ifndef LLVM_TOOLS_LLVM_EXEGESIS_SNIPPETGENERATOR_H
  17 #define LLVM_TOOLS_LLVM_EXEGESIS_SNIPPETGENERATOR_H
  18
  19 #include "Assembler.h"
  20 #include "BenchmarkCode.h"
  21 #include "LlvmState.h"
  22 #include "MCInstrDescView.h"
  23 #include "RegisterAliasing.h"
  24 #include "llvm/MC/MCInst.h"
  25 #include "llvm/Support/Error.h"
  26 #include <cstdlib>
  27 #include <memory>
  28 #include <vector>
  29
  30 namespace exegesis {
  31
  32 // A class representing failures that happened during Benchmark, they are used
  33 // to report informations to the user.
  34 class SnippetGeneratorFailure : public llvm::StringError {
  35 public:
  36   SnippetGeneratorFailure(const llvm::Twine &S);
  37 };
  38
  39 // Common code for all benchmark modes.
  40 class SnippetGenerator {
  41 public:
  42   explicit SnippetGenerator(const LLVMState &State);
  43
  44   virtual ~SnippetGenerator();
  45
  46   // Calls generateCodeTemplate and expands it into one or more BenchmarkCode.
  47   llvm::Expected<std::vector<BenchmarkCode>>
  48   generateConfigurations(unsigned Opcode) const;
  49
  50   // Given a snippet, computes which registers the setup code needs to define.
  51   std::vector<RegisterValue> computeRegisterInitialValues(
  52       const std::vector<InstructionBuilder> &Snippet) const;
  53
  54 protected:
  55   const LLVMState &State;
  56   const RegisterAliasingTrackerCache RATC;
  57
  58   // Generates a single code template that has a self-dependency.
  59   llvm::Expected<CodeTemplate>
  60   generateSelfAliasingCodeTemplate(const Instruction &Instr) const;
  61   // Generates a single code template without assignment constraints.
  62   llvm::Expected<CodeTemplate>
  63   generateUnconstrainedCodeTemplate(const Instruction &Instr,
  64                                     llvm::StringRef Msg) const;
  65
  66 private:
  67   // API to be implemented by subclasses.
  68   virtual llvm::Expected<CodeTemplate>
  69   generateCodeTemplate(unsigned Opcode) const = 0;
  70 };
  71
  72 } // namespace exegesis
  73
  74 #endif // LLVM_TOOLS_LLVM_EXEGESIS_SNIPPETGENERATOR_H