1 //===------ EPCEHFrameRegistrar.cpp - EPC-based eh-frame 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/EPCEHFrameRegistrar.h"
10 
11 #include "llvm/ExecutionEngine/Orc/Core.h"
12 #include "llvm/Support/BinaryStreamWriter.h"
13 
14 using namespace llvm::orc::shared;
15 
16 namespace llvm {
17 namespace orc {
18 
19 Expected<std::unique_ptr<EPCEHFrameRegistrar>> EPCEHFrameRegistrar::Create(
20     ExecutionSession &ES,
21     std::optional<ExecutorAddr> RegistrationFunctionsDylib) {
22   // FIXME: Proper mangling here -- we really need to decouple linker mangling
23   // from DataLayout.
24 
25   // Find the addresses of the registration/deregistration functions in the
26   // executor process.
27   auto &EPC = ES.getExecutorProcessControl();
28 
29   if (!RegistrationFunctionsDylib) {
30     if (auto D = EPC.loadDylib(nullptr))
31       RegistrationFunctionsDylib = *D;
32     else
33       return D.takeError();
34   }
35 
36   std::string RegisterWrapperName, DeregisterWrapperName;
37   if (EPC.getTargetTriple().isOSBinFormatMachO()) {
38     RegisterWrapperName += '_';
39     DeregisterWrapperName += '_';
40   }
41   RegisterWrapperName += "llvm_orc_registerEHFrameSectionWrapper";
42   DeregisterWrapperName += "llvm_orc_deregisterEHFrameSectionWrapper";
43 
44   SymbolLookupSet RegistrationSymbols;
45   RegistrationSymbols.add(EPC.intern(RegisterWrapperName));
46   RegistrationSymbols.add(EPC.intern(DeregisterWrapperName));
47 
48   auto Result =
49       EPC.lookupSymbols({{*RegistrationFunctionsDylib, RegistrationSymbols}});
50   if (!Result)
51     return Result.takeError();
52 
53   assert(Result->size() == 1 && "Unexpected number of dylibs in result");
54   assert((*Result)[0].size() == 2 &&
55          "Unexpected number of addresses in result");
56 
57   auto RegisterEHFrameWrapperFnAddr = (*Result)[0][0];
58   auto DeregisterEHFrameWrapperFnAddr = (*Result)[0][1];
59 
60   return std::make_unique<EPCEHFrameRegistrar>(
61       ES, ExecutorAddr(RegisterEHFrameWrapperFnAddr),
62       ExecutorAddr(DeregisterEHFrameWrapperFnAddr));
63 }
64 
65 Error EPCEHFrameRegistrar::registerEHFrames(ExecutorAddrRange EHFrameSection) {
66   return ES.callSPSWrapper<void(SPSExecutorAddrRange)>(
67       RegisterEHFrameWrapperFnAddr, EHFrameSection);
68 }
69 
70 Error EPCEHFrameRegistrar::deregisterEHFrames(
71     ExecutorAddrRange EHFrameSection) {
72   return ES.callSPSWrapper<void(SPSExecutorAddrRange)>(
73       DeregisterEHFrameWrapperFnAddr, EHFrameSection);
74 }
75 
76 } // end namespace orc
77 } // end namespace llvm
78