tools/llvm-exegesis/lib/Assembler.h

   1 //===-- Assembler.h ---------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 ///
   9 /// \file
  10 /// Defines classes to assemble functions composed of a single basic block of
  11 /// MCInsts.
  12 ///
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef LLVM_TOOLS_LLVM_EXEGESIS_ASSEMBLER_H
  16 #define LLVM_TOOLS_LLVM_EXEGESIS_ASSEMBLER_H
  17
  18 #include <memory>
  19
  20 #include "BenchmarkCode.h"
  21 #include "llvm/ADT/ArrayRef.h"
  22 #include "llvm/ADT/BitVector.h"
  23 #include "llvm/CodeGen/MachineFunction.h"
  24 #include "llvm/CodeGen/MachineModuleInfo.h"
  25 #include "llvm/ExecutionEngine/ExecutionEngine.h"
  26 #include "llvm/IR/LLVMContext.h"
  27 #include "llvm/IR/Module.h"
  28 #include "llvm/MC/MCInst.h"
  29 #include "llvm/Object/Binary.h"
  30 #include "llvm/Object/ObjectFile.h"
  31 #include "llvm/Support/raw_ostream.h"
  32 #include "llvm/Target/TargetMachine.h"
  33
  34 namespace llvm {
  35 namespace exegesis {
  36
  37 class ExegesisTarget;
  38
  39 // Gather the set of reserved registers (depends on function's calling
  40 // convention and target machine).
  41 llvm::BitVector getFunctionReservedRegs(const llvm::TargetMachine &TM);
  42
  43 // Creates a temporary `void foo(char*)` function containing the provided
  44 // Instructions. Runs a set of llvm Passes to provide correct prologue and
  45 // epilogue. Once the MachineFunction is ready, it is assembled for TM to
  46 // AsmStream, the temporary function is eventually discarded.
  47 void assembleToStream(const ExegesisTarget &ET,
  48                       std::unique_ptr<llvm::LLVMTargetMachine> TM,
  49                       llvm::ArrayRef<unsigned> LiveIns,
  50                       llvm::ArrayRef<RegisterValue> RegisterInitialValues,
  51                       llvm::ArrayRef<llvm::MCInst> Instructions,
  52                       llvm::raw_pwrite_stream &AsmStream);
  53
  54 // Creates an ObjectFile in the format understood by the host.
  55 // Note: the resulting object keeps a copy of Buffer so it can be discarded once
  56 // this function returns.
  57 llvm::object::OwningBinary<llvm::object::ObjectFile>
  58 getObjectFromBuffer(llvm::StringRef Buffer);
  59
  60 // Loads the content of Filename as on ObjectFile and returns it.
  61 llvm::object::OwningBinary<llvm::object::ObjectFile>
  62 getObjectFromFile(llvm::StringRef Filename);
  63
  64 // Consumes an ObjectFile containing a `void foo(char*)` function and make it
  65 // executable.
  66 struct ExecutableFunction {
  67   explicit ExecutableFunction(
  68       std::unique_ptr<llvm::LLVMTargetMachine> TM,
  69       llvm::object::OwningBinary<llvm::object::ObjectFile> &&ObjectFileHolder);
  70
  71   // Retrieves the function as an array of bytes.
  72   llvm::StringRef getFunctionBytes() const { return FunctionBytes; }
  73
  74   // Executes the function.
  75   void operator()(char *Memory) const {
  76     ((void (*)(char *))(intptr_t)FunctionBytes.data())(Memory);
  77   }
  78
  79   std::unique_ptr<llvm::LLVMContext> Context;
  80   std::unique_ptr<llvm::ExecutionEngine> ExecEngine;
  81   llvm::StringRef FunctionBytes;
  82 };
  83
  84 } // namespace exegesis
  85 } // namespace llvm
  86
  87 #endif // LLVM_TOOLS_LLVM_EXEGESIS_ASSEMBLER_H