1 //===------- UnwindInfoManager.cpp - Register unwind info sections --------===//
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/TargetProcess/UnwindInfoManager.h"
10 #include "llvm/ExecutionEngine/Orc/Shared/OrcRTBridge.h"
11 #include "llvm/ExecutionEngine/Orc/Shared/WrapperFunctionUtils.h"
12
13 #ifdef __APPLE__
14 #include <dlfcn.h>
15 #endif // __APPLE__
16
17 #define DEBUG_TYPE "orc"
18
19 using namespace llvm;
20 using namespace llvm::orc;
21 using namespace llvm::orc::shared;
22
23 static orc::shared::CWrapperFunctionResult
llvm_orc_rt_alt_UnwindInfoManager_register(const char * ArgData,size_t ArgSize)24 llvm_orc_rt_alt_UnwindInfoManager_register(const char *ArgData,
25 size_t ArgSize) {
26 using SPSSig = SPSError(SPSSequence<SPSExecutorAddrRange>, SPSExecutorAddr,
27 SPSExecutorAddrRange, SPSExecutorAddrRange);
28
29 return WrapperFunction<SPSSig>::handle(
30 ArgData, ArgSize,
31 [](std::vector<ExecutorAddrRange> CodeRanges, ExecutorAddr DSOBase,
32 ExecutorAddrRange DWARFRange,
33 ExecutorAddrRange CompactUnwindRange) {
34 return UnwindInfoManager::registerSections(
35 CodeRanges, DSOBase, DWARFRange, CompactUnwindRange);
36 })
37 .release();
38 }
39
40 static orc::shared::CWrapperFunctionResult
llvm_orc_rt_alt_UnwindInfoManager_deregister(const char * ArgData,size_t ArgSize)41 llvm_orc_rt_alt_UnwindInfoManager_deregister(const char *ArgData,
42 size_t ArgSize) {
43 using SPSSig = SPSError(SPSSequence<SPSExecutorAddrRange>);
44
45 return WrapperFunction<SPSSig>::handle(
46 ArgData, ArgSize,
47 [](std::vector<ExecutorAddrRange> CodeRanges) {
48 return UnwindInfoManager::deregisterSections(CodeRanges);
49 })
50 .release();
51 }
52
53 namespace llvm::orc {
54
55 [[maybe_unused]] static const char *AddFnName =
56 "__unw_add_find_dynamic_unwind_sections";
57 [[maybe_unused]] static const char *RemoveFnName =
58 "__unw_remove_find_dynamic_unwind_sections";
59 static std::unique_ptr<UnwindInfoManager> Instance;
60 static int (*RemoveFindDynamicUnwindSections)(void *) = nullptr;
61
~UnwindInfoManager()62 UnwindInfoManager::~UnwindInfoManager() {
63 if (int Err = RemoveFindDynamicUnwindSections((void *)&findSections)) {
64 (void)Err; // Silence unused variable warning in release builds.
65 LLVM_DEBUG({
66 dbgs() << "Failed call to " << RemoveFnName << ": error = " << Err
67 << "\n";
68 });
69 (void)Err;
70 }
71 }
72
TryEnable()73 bool UnwindInfoManager::TryEnable() {
74 #ifdef __APPLE__
75 static std::mutex M;
76 std::lock_guard<std::mutex> Lock(M);
77
78 if (Instance)
79 return true;
80
81 auto AddFn = (int (*)(void *))dlsym(RTLD_DEFAULT, AddFnName);
82 if (!AddFn)
83 return false;
84
85 auto RemoveFn = (int (*)(void *))dlsym(RTLD_DEFAULT, RemoveFnName);
86 if (!RemoveFn)
87 return false;
88
89 Instance.reset(new UnwindInfoManager());
90
91 if (auto Err = AddFn((void *)&findSections)) {
92 (void)Err; // Silence unused variable warning in release builds.
93 LLVM_DEBUG({
94 dbgs() << "Failed call to " << AddFnName << ": error = " << Err << "\n";
95 });
96 Instance = nullptr;
97 return false;
98 }
99
100 RemoveFindDynamicUnwindSections = RemoveFn;
101 return true;
102
103 #else
104 return false;
105 #endif // __APPLE__
106 }
107
addBootstrapSymbols(StringMap<ExecutorAddr> & M)108 void UnwindInfoManager::addBootstrapSymbols(StringMap<ExecutorAddr> &M) {
109 M[rt_alt::UnwindInfoManagerRegisterActionName] =
110 ExecutorAddr::fromPtr(llvm_orc_rt_alt_UnwindInfoManager_register);
111 M[rt_alt::UnwindInfoManagerDeregisterActionName] =
112 ExecutorAddr::fromPtr(llvm_orc_rt_alt_UnwindInfoManager_deregister);
113 }
114
registerSections(ArrayRef<orc::ExecutorAddrRange> CodeRanges,orc::ExecutorAddr DSOBase,orc::ExecutorAddrRange DWARFEHFrame,orc::ExecutorAddrRange CompactUnwind)115 Error UnwindInfoManager::registerSections(
116 ArrayRef<orc::ExecutorAddrRange> CodeRanges, orc::ExecutorAddr DSOBase,
117 orc::ExecutorAddrRange DWARFEHFrame, orc::ExecutorAddrRange CompactUnwind) {
118 return Instance->registerSectionsImpl(CodeRanges, DSOBase, DWARFEHFrame,
119 CompactUnwind);
120 }
121
deregisterSections(ArrayRef<orc::ExecutorAddrRange> CodeRanges)122 Error UnwindInfoManager::deregisterSections(
123 ArrayRef<orc::ExecutorAddrRange> CodeRanges) {
124 return Instance->deregisterSectionsImpl(CodeRanges);
125 }
126
findSectionsImpl(uintptr_t Addr,UnwindSections * Info)127 int UnwindInfoManager::findSectionsImpl(uintptr_t Addr, UnwindSections *Info) {
128 std::lock_guard<std::mutex> Lock(M);
129 auto I = UWSecs.upper_bound(Addr);
130 if (I == UWSecs.begin())
131 return 0;
132 --I;
133 *Info = I->second;
134 return 1;
135 }
136
findSections(uintptr_t Addr,UnwindSections * Info)137 int UnwindInfoManager::findSections(uintptr_t Addr, UnwindSections *Info) {
138 return Instance->findSectionsImpl(Addr, Info);
139 }
140
registerSectionsImpl(ArrayRef<ExecutorAddrRange> CodeRanges,ExecutorAddr DSOBase,ExecutorAddrRange DWARFEHFrame,ExecutorAddrRange CompactUnwind)141 Error UnwindInfoManager::registerSectionsImpl(
142 ArrayRef<ExecutorAddrRange> CodeRanges, ExecutorAddr DSOBase,
143 ExecutorAddrRange DWARFEHFrame, ExecutorAddrRange CompactUnwind) {
144 std::lock_guard<std::mutex> Lock(M);
145 for (auto &R : CodeRanges)
146 UWSecs[R.Start.getValue()] =
147 UnwindSections{static_cast<uintptr_t>(DSOBase.getValue()),
148 static_cast<uintptr_t>(DWARFEHFrame.Start.getValue()),
149 static_cast<size_t>(DWARFEHFrame.size()),
150 static_cast<uintptr_t>(CompactUnwind.Start.getValue()),
151 static_cast<size_t>(CompactUnwind.size())};
152 return Error::success();
153 }
154
deregisterSectionsImpl(ArrayRef<ExecutorAddrRange> CodeRanges)155 Error UnwindInfoManager::deregisterSectionsImpl(
156 ArrayRef<ExecutorAddrRange> CodeRanges) {
157 std::lock_guard<std::mutex> Lock(M);
158 for (auto &R : CodeRanges) {
159 auto I = UWSecs.find(R.Start.getValue());
160 if (I == UWSecs.end())
161 return make_error<StringError>(
162 "No unwind-info sections registered for range " +
163 formatv("{0:x} - {1:x}", R.Start, R.End),
164 inconvertibleErrorCode());
165 UWSecs.erase(I);
166 }
167 return Error::success();
168 }
169
170 } // namespace llvm::orc
171