1 //===- JITLoaderGDB.h - Register objects via GDB JIT interface -*- 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 #include "llvm/ExecutionEngine/Orc/TargetProcess/JITLoaderGDB.h"
10
11 #include "llvm/ExecutionEngine/JITSymbol.h"
12 #include "llvm/Support/BinaryStreamReader.h"
13 #include "llvm/Support/FormatVariadic.h"
14
15 #include <cstdint>
16 #include <mutex>
17 #include <utility>
18
19 #define DEBUG_TYPE "orc"
20
21 // First version as landed in August 2009
22 static constexpr uint32_t JitDescriptorVersion = 1;
23
24 extern "C" {
25
26 // We put information about the JITed function in this global, which the
27 // debugger reads. Make sure to specify the version statically, because the
28 // debugger checks the version before we can set it during runtime.
29 struct jit_descriptor __jit_debug_descriptor = {JitDescriptorVersion, 0,
30 nullptr, nullptr};
31
32 // Debuggers that implement the GDB JIT interface put a special breakpoint in
33 // this function.
__jit_debug_register_code()34 LLVM_ATTRIBUTE_NOINLINE void __jit_debug_register_code() {
35 // The noinline and the asm prevent calls to this function from being
36 // optimized out.
37 #if !defined(_MSC_VER)
38 asm volatile("" ::: "memory");
39 #endif
40 }
41 }
42
43 using namespace llvm;
44 using namespace llvm::orc;
45
46 // Register debug object, return error message or null for success.
appendJITDebugDescriptor(const char * ObjAddr,size_t Size)47 static void appendJITDebugDescriptor(const char *ObjAddr, size_t Size) {
48 LLVM_DEBUG({
49 dbgs() << "Adding debug object to GDB JIT interface "
50 << formatv("([{0:x16} -- {1:x16}])",
51 reinterpret_cast<uintptr_t>(ObjAddr),
52 reinterpret_cast<uintptr_t>(ObjAddr + Size))
53 << "\n";
54 });
55
56 jit_code_entry *E = new jit_code_entry;
57 E->symfile_addr = ObjAddr;
58 E->symfile_size = Size;
59 E->prev_entry = nullptr;
60
61 // Serialize rendezvous with the debugger as well as access to shared data.
62 static std::mutex JITDebugLock;
63 std::lock_guard<std::mutex> Lock(JITDebugLock);
64
65 // Insert this entry at the head of the list.
66 jit_code_entry *NextEntry = __jit_debug_descriptor.first_entry;
67 E->next_entry = NextEntry;
68 if (NextEntry) {
69 NextEntry->prev_entry = E;
70 }
71
72 __jit_debug_descriptor.first_entry = E;
73 __jit_debug_descriptor.relevant_entry = E;
74 __jit_debug_descriptor.action_flag = JIT_REGISTER_FN;
75 }
76
77 extern "C" orc::shared::CWrapperFunctionResult
llvm_orc_registerJITLoaderGDBAllocAction(const char * Data,size_t Size)78 llvm_orc_registerJITLoaderGDBAllocAction(const char *Data, size_t Size) {
79 using namespace orc::shared;
80 return WrapperFunction<SPSError(SPSExecutorAddrRange, bool)>::handle(
81 Data, Size,
82 [](ExecutorAddrRange R, bool AutoRegisterCode) {
83 appendJITDebugDescriptor(R.Start.toPtr<const char *>(),
84 R.size());
85 // Run into the rendezvous breakpoint.
86 if (AutoRegisterCode)
87 __jit_debug_register_code();
88 return Error::success();
89 })
90 .release();
91 }
92
93 extern "C" orc::shared::CWrapperFunctionResult
llvm_orc_registerJITLoaderGDBWrapper(const char * Data,uint64_t Size)94 llvm_orc_registerJITLoaderGDBWrapper(const char *Data, uint64_t Size) {
95 using namespace orc::shared;
96 return WrapperFunction<SPSError(SPSExecutorAddrRange, bool)>::handle(
97 Data, Size,
98 [](ExecutorAddrRange R, bool AutoRegisterCode) {
99 appendJITDebugDescriptor(R.Start.toPtr<const char *>(),
100 R.size());
101 // Run into the rendezvous breakpoint.
102 if (AutoRegisterCode)
103 __jit_debug_register_code();
104 return Error::success();
105 })
106 .release();
107 }
108