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 "BenchmarkCode.h"
22 #include "llvm/ADT/ArrayRef.h"
23 #include "llvm/ADT/BitVector.h"
24 #include "llvm/CodeGen/MachineFunction.h"
25 #include "llvm/CodeGen/MachineModuleInfo.h"
26 #include "llvm/ExecutionEngine/ExecutionEngine.h"
27 #include "llvm/IR/LLVMContext.h"
28 #include "llvm/IR/Module.h"
29 #include "llvm/MC/MCInst.h"
30 #include "llvm/Object/Binary.h"
31 #include "llvm/Object/ObjectFile.h"
32 #include "llvm/Support/raw_ostream.h"
33 #include "llvm/Target/TargetMachine.h"
34 
35 namespace llvm {
36 namespace exegesis {
37 
38 class ExegesisTarget;
39 
40 // Gather the set of reserved registers (depends on function's calling
41 // convention and target machine).
42 llvm::BitVector getFunctionReservedRegs(const llvm::TargetMachine &TM);
43 
44 // Creates a temporary `void foo(char*)` function containing the provided
45 // Instructions. Runs a set of llvm Passes to provide correct prologue and
46 // epilogue. Once the MachineFunction is ready, it is assembled for TM to
47 // AsmStream, the temporary function is eventually discarded.
48 void assembleToStream(const ExegesisTarget &ET,
49                       std::unique_ptr<llvm::LLVMTargetMachine> TM,
50                       llvm::ArrayRef<unsigned> LiveIns,
51                       llvm::ArrayRef<RegisterValue> RegisterInitialValues,
52                       llvm::ArrayRef<llvm::MCInst> Instructions,
53                       llvm::raw_pwrite_stream &AsmStream);
54 
55 // Creates an ObjectFile in the format understood by the host.
56 // Note: the resulting object keeps a copy of Buffer so it can be discarded once
57 // this function returns.
58 llvm::object::OwningBinary<llvm::object::ObjectFile>
59 getObjectFromBuffer(llvm::StringRef Buffer);
60 
61 // Loads the content of Filename as on ObjectFile and returns it.
62 llvm::object::OwningBinary<llvm::object::ObjectFile>
63 getObjectFromFile(llvm::StringRef Filename);
64 
65 // Consumes an ObjectFile containing a `void foo(char*)` function and make it
66 // executable.
67 struct ExecutableFunction {
68   explicit ExecutableFunction(
69       std::unique_ptr<llvm::LLVMTargetMachine> TM,
70       llvm::object::OwningBinary<llvm::object::ObjectFile> &&ObjectFileHolder);
71 
72   // Retrieves the function as an array of bytes.
getFunctionBytesExecutableFunction73   llvm::StringRef getFunctionBytes() const { return FunctionBytes; }
74 
75   // Executes the function.
operatorExecutableFunction76   void operator()(char *Memory) const {
77     ((void (*)(char *))(intptr_t)FunctionBytes.data())(Memory);
78   }
79 
80   std::unique_ptr<llvm::LLVMContext> Context;
81   std::unique_ptr<llvm::ExecutionEngine> ExecEngine;
82   llvm::StringRef FunctionBytes;
83 };
84 
85 } // namespace exegesis
86 } // namespace llvm
87 
88 #endif // LLVM_TOOLS_LLVM_EXEGESIS_ASSEMBLER_H
89