1 //===-LTOBackend.h - LLVM Link Time Optimizer Backend ---------------------===//
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 // This file implements the "backend" phase of LTO, i.e. it performs
10 // optimization and code generation on a loaded module. It is generally used
11 // internally by the LTO class but can also be used independently, for example
12 // to implement a standalone ThinLTO backend.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_LTO_LTOBACKEND_H
17 #define LLVM_LTO_LTOBACKEND_H
18 
19 #include "llvm/ADT/MapVector.h"
20 #include "llvm/IR/DiagnosticInfo.h"
21 #include "llvm/IR/ModuleSummaryIndex.h"
22 #include "llvm/LTO/LTO.h"
23 #include "llvm/Support/MemoryBuffer.h"
24 #include "llvm/Target/TargetOptions.h"
25 #include "llvm/Transforms/IPO/FunctionImport.h"
26 
27 namespace llvm {
28 
29 class BitcodeModule;
30 class Error;
31 class Module;
32 class Target;
33 
34 namespace lto {
35 
36 /// Runs middle-end LTO optimizations on \p Mod.
37 bool opt(const Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod,
38          bool IsThinLTO, ModuleSummaryIndex *ExportSummary,
39          const ModuleSummaryIndex *ImportSummary,
40          const std::vector<uint8_t> &CmdArgs);
41 
42 /// Runs a regular LTO backend. The regular LTO backend can also act as the
43 /// regular LTO phase of ThinLTO, which may need to access the combined index.
44 Error backend(const Config &C, AddStreamFn AddStream,
45               unsigned ParallelCodeGenParallelismLevel, Module &M,
46               ModuleSummaryIndex &CombinedIndex);
47 
48 /// Runs a ThinLTO backend.
49 /// If \p ModuleMap is not nullptr, all the module files to be imported have
50 /// already been mapped to memory and the corresponding BitcodeModule objects
51 /// are saved in the ModuleMap. If \p ModuleMap is nullptr, module files will
52 /// be mapped to memory on demand and at any given time during importing, only
53 /// one source module will be kept open at the most.
54 Error thinBackend(const Config &C, unsigned Task, AddStreamFn AddStream,
55                   Module &M, const ModuleSummaryIndex &CombinedIndex,
56                   const FunctionImporter::ImportMapTy &ImportList,
57                   const GVSummaryMapTy &DefinedGlobals,
58                   MapVector<StringRef, BitcodeModule> *ModuleMap,
59                   const std::vector<uint8_t> &CmdArgs = std::vector<uint8_t>());
60 
61 Error finalizeOptimizationRemarks(
62     std::unique_ptr<ToolOutputFile> DiagOutputFile);
63 
64 /// Returns the BitcodeModule that is ThinLTO.
65 BitcodeModule *findThinLTOModule(MutableArrayRef<BitcodeModule> BMs);
66 
67 /// Variant of the above.
68 Expected<BitcodeModule> findThinLTOModule(MemoryBufferRef MBRef);
69 
70 /// Distributed ThinLTO: collect the referenced modules based on
71 /// module summary and initialize ImportList. Returns false if the
72 /// operation failed.
73 bool initImportList(const Module &M, const ModuleSummaryIndex &CombinedIndex,
74                     FunctionImporter::ImportMapTy &ImportList);
75 }
76 }
77 
78 #endif
79