1//===----- UnwindInfoRegistrationPlugin.cpp - libunwind registration ------===//
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#include "llvm/ExecutionEngine/Orc/UnwindInfoRegistrationPlugin.h"
10
11#include "llvm/ExecutionEngine/Orc/Shared/MachOObjectFormat.h"
12#include "llvm/ExecutionEngine/Orc/Shared/OrcRTBridge.h"
13#include "llvm/IR/Module.h"
14
15#define DEBUG_TYPE "orc"
16
17using namespace llvm::jitlink;
18
19namespace llvm::orc {
20
21Expected<std::shared_ptr<UnwindInfoRegistrationPlugin>>
22UnwindInfoRegistrationPlugin::Create(
23 ExecutionSession &ES, rt::MachOUnwindInfoRegistrarSymbolNames SNs) {
24
25 ExecutorAddr RegisterSections, DeregisterSections;
26
27 auto &EPC = ES.getExecutorProcessControl();
28 if (auto Err = EPC.getBootstrapSymbols(
29 Pairs: {{RegisterSections, SNs.RegisterSectionsName},
30 {DeregisterSections, SNs.DeregisterSectionsName}}))
31 return std::move(Err);
32
33 return std::make_shared<UnwindInfoRegistrationPlugin>(args&: ES, args&: RegisterSections,
34 args&: DeregisterSections);
35}
36
37void UnwindInfoRegistrationPlugin::modifyPassConfig(
38 MaterializationResponsibility &MR, LinkGraph &G,
39 PassConfiguration &PassConfig) {
40
41 PassConfig.PostFixupPasses.push_back(
42 x: [this](LinkGraph &G) { return addUnwindInfoRegistrationActions(G); });
43}
44
45Error UnwindInfoRegistrationPlugin::addUnwindInfoRegistrationActions(
46 LinkGraph &G) {
47 ExecutorAddrRange EHFrameRange, UnwindInfoRange;
48
49 std::vector<Block *> CodeBlocks;
50
51 auto ScanUnwindInfoSection = [&](Section &Sec, ExecutorAddrRange &SecRange) {
52 if (Sec.empty())
53 return;
54
55 SecRange.Start = (*Sec.blocks().begin())->getAddress();
56 for (auto *B : Sec.blocks()) {
57 auto R = B->getRange();
58 SecRange.Start = std::min(a: SecRange.Start, b: R.Start);
59 SecRange.End = std::max(a: SecRange.End, b: R.End);
60 for (auto &E : B->edges()) {
61 if (E.getKind() != Edge::KeepAlive || !E.getTarget().isDefined())
62 continue;
63 auto &TargetBlock = E.getTarget().getBlock();
64 auto &TargetSection = TargetBlock.getSection();
65 if ((TargetSection.getMemProt() & MemProt::Exec) == MemProt::Exec)
66 CodeBlocks.push_back(x: &TargetBlock);
67 }
68 }
69 };
70
71 if (auto *EHFrame = G.findSectionByName(Name: MachOEHFrameSectionName))
72 ScanUnwindInfoSection(*EHFrame, EHFrameRange);
73
74 if (auto *UnwindInfo = G.findSectionByName(Name: MachOUnwindInfoSectionName))
75 ScanUnwindInfoSection(*UnwindInfo, UnwindInfoRange);
76
77 if (CodeBlocks.empty())
78 return Error::success();
79
80 if ((EHFrameRange == ExecutorAddrRange() &&
81 UnwindInfoRange == ExecutorAddrRange()))
82 return Error::success();
83
84 llvm::sort(C&: CodeBlocks, Comp: [](const Block *LHS, const Block *RHS) {
85 return LHS->getAddress() < RHS->getAddress();
86 });
87
88 SmallVector<ExecutorAddrRange> CodeRanges;
89 for (auto *B : CodeBlocks) {
90 if (CodeRanges.empty() || CodeRanges.back().End != B->getAddress())
91 CodeRanges.push_back(Elt: B->getRange());
92 else
93 CodeRanges.back().End = B->getRange().End;
94 }
95
96 ExecutorAddr DSOBase;
97 if (auto *DSOBaseSym = G.findAbsoluteSymbolByName(Name: DSOBaseName))
98 DSOBase = DSOBaseSym->getAddress();
99 else if (auto *DSOBaseSym = G.findExternalSymbolByName(Name: DSOBaseName))
100 DSOBase = DSOBaseSym->getAddress();
101 else if (auto *DSOBaseSym = G.findDefinedSymbolByName(Name: DSOBaseName))
102 DSOBase = DSOBaseSym->getAddress();
103 else
104 return make_error<StringError>(Args: "In " + G.getName() +
105 " could not find dso base symbol",
106 Args: inconvertibleErrorCode());
107
108 using namespace shared;
109 using SPSRegisterSectionsArgs =
110 SPSArgList<SPSSequence<SPSExecutorAddrRange>, SPSExecutorAddr,
111 SPSExecutorAddrRange, SPSExecutorAddrRange>;
112 using SPSDeregisterSectionsArgs =
113 SPSArgList<SPSSequence<SPSExecutorAddrRange>>;
114
115 G.allocActions().push_back(
116 x: {.Finalize: cantFail(ValOrErr: WrapperFunctionCall::Create<SPSRegisterSectionsArgs>(
117 FnAddr: RegisterSections, Args: CodeRanges, Args: DSOBase, Args: EHFrameRange,
118 Args: UnwindInfoRange)),
119 .Dealloc: cantFail(ValOrErr: WrapperFunctionCall::Create<SPSDeregisterSectionsArgs>(
120 FnAddr: DeregisterSections, Args: CodeRanges))});
121
122 return Error::success();
123}
124
125} // namespace llvm::orc
126