1 //===-- Assembler.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 classes to assemble functions composed of a single basic block of 12 /// MCInsts. 13 /// 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_TOOLS_LLVM_EXEGESIS_ASSEMBLER_H 17 #define LLVM_TOOLS_LLVM_EXEGESIS_ASSEMBLER_H 18 19 #include <memory> 20 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 exegesis { 35 36 class ExegesisTarget; 37 38 // Gather the set of reserved registers (depends on function's calling 39 // convention and target machine). 40 llvm::BitVector getFunctionReservedRegs(const llvm::TargetMachine &TM); 41 42 // Creates a temporary `void foo()` function containing the provided 43 // Instructions. Runs a set of llvm Passes to provide correct prologue and 44 // epilogue. Once the MachineFunction is ready, it is assembled for TM to 45 // AsmStream, the temporary function is eventually discarded. 46 void assembleToStream(const ExegesisTarget &ET, 47 std::unique_ptr<llvm::LLVMTargetMachine> TM, 48 llvm::ArrayRef<unsigned> RegsToDef, 49 llvm::ArrayRef<llvm::MCInst> Instructions, 50 llvm::raw_pwrite_stream &AsmStream); 51 52 // Creates an ObjectFile in the format understood by the host. 53 // Note: the resulting object keeps a copy of Buffer so it can be discarded once 54 // this function returns. 55 llvm::object::OwningBinary<llvm::object::ObjectFile> 56 getObjectFromBuffer(llvm::StringRef Buffer); 57 58 // Loads the content of Filename as on ObjectFile and returns it. 59 llvm::object::OwningBinary<llvm::object::ObjectFile> 60 getObjectFromFile(llvm::StringRef Filename); 61 62 // Consumes an ObjectFile containing a `void foo()` function and make it 63 // executable. 64 struct ExecutableFunction { 65 explicit ExecutableFunction( 66 std::unique_ptr<llvm::LLVMTargetMachine> TM, 67 llvm::object::OwningBinary<llvm::object::ObjectFile> &&ObjectFileHolder); 68 69 // Retrieves the function as an array of bytes. getFunctionBytesExecutableFunction70 llvm::StringRef getFunctionBytes() const { return FunctionBytes; } 71 72 // Executes the function. operatorExecutableFunction73 void operator()() const { ((void (*)())(intptr_t)FunctionBytes.data())(); } 74 75 std::unique_ptr<llvm::LLVMContext> Context; 76 std::unique_ptr<llvm::ExecutionEngine> ExecEngine; 77 llvm::StringRef FunctionBytes; 78 }; 79 80 } // namespace exegesis 81 82 #endif // LLVM_TOOLS_LLVM_EXEGESIS_ASSEMBLER_H 83