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 "Error.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/Orc/LLJIT.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
35namespace llvm {
36namespace exegesis {
37
38class ExegesisTarget;
39
40// Gather the set of reserved registers (depends on function's calling
41// convention and target machine).
42BitVector getFunctionReservedRegs(const TargetMachine &TM);
43
44// Helper to fill in a basic block.
45class BasicBlockFiller {
46public:
47 BasicBlockFiller(MachineFunction &MF, MachineBasicBlock *MBB,
48 const MCInstrInfo *MCII);
49
50 void addInstruction(const MCInst &Inst, const DebugLoc &DL = DebugLoc());
51 void addInstructions(ArrayRef<MCInst> Insts, const DebugLoc &DL = DebugLoc());
52
53 void addReturn(const ExegesisTarget &ET, bool SubprocessCleanup,
54 const DebugLoc &DL = DebugLoc());
55
56 MachineFunction &MF;
57 MachineBasicBlock *const MBB;
58 const MCInstrInfo *const MCII;
59};
60
61// Helper to fill in a function.
62class FunctionFiller {
63public:
64 FunctionFiller(MachineFunction &MF, std::vector<unsigned> RegistersSetUp);
65
66 // Adds a basic block to the function.
67 BasicBlockFiller addBasicBlock();
68
69 // Returns the function entry point.
70 BasicBlockFiller getEntry() { return Entry; }
71
72 MachineFunction &MF;
73 const MCInstrInfo *const MCII;
74
75 // Returns the set of registers in the snippet setup code.
76 ArrayRef<unsigned> getRegistersSetUp() const;
77
78private:
79 BasicBlockFiller Entry;
80 // The set of registers that are set up in the basic block.
81 std::vector<unsigned> RegistersSetUp;
82};
83
84// A callback that fills a function.
85using FillFunction = std::function<void(FunctionFiller &)>;
86
87// Creates a temporary `void foo(char*)` function containing the provided
88// Instructions. Runs a set of llvm Passes to provide correct prologue and
89// epilogue. Once the MachineFunction is ready, it is assembled for TM to
90// AsmStream, the temporary function is eventually discarded.
91Error assembleToStream(const ExegesisTarget &ET,
92 std::unique_ptr<LLVMTargetMachine> TM,
93 ArrayRef<unsigned> LiveIns, const FillFunction &Fill,
94 raw_pwrite_stream &AsmStreamm, const BenchmarkKey &Key,
95 bool GenerateMemoryInstructions);
96
97// Creates an ObjectFile in the format understood by the host.
98// Note: the resulting object keeps a copy of Buffer so it can be discarded once
99// this function returns.
100object::OwningBinary<object::ObjectFile> getObjectFromBuffer(StringRef Buffer);
101
102// Loads the content of Filename as on ObjectFile and returns it.
103object::OwningBinary<object::ObjectFile> getObjectFromFile(StringRef Filename);
104
105// Consumes an ObjectFile containing a `void foo(char*)` function and make it
106// executable.
107class ExecutableFunction {
108public:
109 static Expected<ExecutableFunction>
110 create(std::unique_ptr<LLVMTargetMachine> TM,
111 object::OwningBinary<object::ObjectFile> &&ObjectFileHolder);
112
113 // Retrieves the function as an array of bytes.
114 StringRef getFunctionBytes() const { return FunctionBytes; }
115
116 // Executes the function.
117 void operator()(char *Memory) const {
118 ((void (*)(char *))(intptr_t)FunctionBytes.data())(Memory);
119 }
120
121 StringRef FunctionBytes;
122
123private:
124 ExecutableFunction(std::unique_ptr<LLVMContext> Ctx,
125 std::unique_ptr<orc::LLJIT> EJIT, StringRef FunctionBytes);
126
127 std::unique_ptr<LLVMContext> Context;
128 std::unique_ptr<orc::LLJIT> ExecJIT;
129};
130
131// Copies benchmark function's bytes from benchmark object.
132Error getBenchmarkFunctionBytes(const StringRef InputData,
133 std::vector<uint8_t> &Bytes);
134
135// Creates a void(int8*) MachineFunction.
136MachineFunction &createVoidVoidPtrMachineFunction(StringRef FunctionID,
137 Module *Module,
138 MachineModuleInfo *MMI);
139
140} // namespace exegesis
141} // namespace llvm
142
143#endif // LLVM_TOOLS_LLVM_EXEGESIS_ASSEMBLER_H
144