Mercurial > hg > CbC > CbC_llvm

comparison lld/MachO/ConcatOutputSection.h @ 207:2e18cbf3894f

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
LLVM12
author Shinji KONO <kono@ie.u-ryukyu.ac.jp>
date Tue, 08 Jun 2021 06:07:14 +0900
parents
children 5f17cb93ff66
comparison
equal deleted inserted replaced
173:0572611fdcc8 207:2e18cbf3894f
1 //===- ConcatOutputSection.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 #ifndef LLD_MACHO_MERGED_OUTPUT_SECTION_H
10 #define LLD_MACHO_MERGED_OUTPUT_SECTION_H
11
12 #include "InputSection.h"
13 #include "OutputSection.h"
14 #include "lld/Common/LLVM.h"
15 #include "llvm/ADT/DenseMap.h"
16 #include "llvm/ADT/MapVector.h"
17
18 namespace lld {
19 namespace macho {
20
21 class Defined;
22
23 // Linking multiple files will inevitably mean resolving sections in different
24 // files that are labeled with the same segment and section name. This class
25 // contains all such sections and writes the data from each section sequentially
26 // in the final binary.
27 class ConcatOutputSection : public OutputSection {
28 public:
29 explicit ConcatOutputSection(StringRef name)
30 : OutputSection(ConcatKind, name) {}
31
32 const InputSection *firstSection() const { return inputs.front(); }
33 const InputSection *lastSection() const { return inputs.back(); }
34
35 // These accessors will only be valid after finalizing the section
36 uint64_t getSize() const override { return size; }
37 uint64_t getFileSize() const override { return fileSize; }
38
39 void addInput(InputSection *input);
40 void finalize() override;
41 bool needsThunks() const;
42 uint64_t estimateStubsInRangeVA(size_t callIdx) const;
43
44 void writeTo(uint8_t *buf) const override;
45
46 std::vector<InputSection *> inputs;
47 std::vector<InputSection *> thunks;
48
49 static bool classof(const OutputSection *sec) {
50 return sec->kind() == ConcatKind;
51 }
52
53 private:
54 void mergeFlags(InputSection *input);
55
56 size_t size = 0;
57 uint64_t fileSize = 0;
58 };
59
60 // We maintain one ThunkInfo per real function.
61 //
62 // The "active thunk" is represented by the sym/isec pair that
63 // turns-over during finalize(): as the call-site address advances,
64 // the active thunk goes out of branch-range, and we create a new
65 // thunk to take its place.
66 //
67 // The remaining members -- bools and counters -- apply to the
68 // collection of thunks associated with the real function.
69
70 struct ThunkInfo {
71 // These denote the active thunk:
72 Defined *sym = nullptr; // private-extern symbol for active thunk
73 InputSection *isec = nullptr; // input section for active thunk
74
75 // The following values are cumulative across all thunks on this function
76 uint32_t callSiteCount = 0; // how many calls to the real function?
77 uint32_t callSitesUsed = 0; // how many call sites processed so-far?
78 uint32_t thunkCallCount = 0; // how many call sites went to thunk?
79 uint8_t sequence = 0; // how many thunks created so-far?
80 };
81
82 extern llvm::DenseMap<Symbol *, ThunkInfo> thunkMap;
83
84 } // namespace macho
85 } // namespace lld
86
87 #endif