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