Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0
2
3/*
4 * Must come before the linux/compiler.h include, which defines several
5 * macros (e.g. noinline) that conflict with compiler builtins used
6 * by LLVM.
7 */
8#pragma GCC diagnostic push
9#pragma GCC diagnostic ignored "-Wunused-parameter" /* Needed for LLVM <= 15 */
10#include <llvm/DebugInfo/Symbolize/Symbolize.h>
11#include <llvm/Support/TargetSelect.h>
12#pragma GCC diagnostic pop
13
14#include <inttypes.h>
15#include <stdio.h>
16#include <sys/types.h>
17#include <linux/compiler.h>
18extern "C" {
19#include <linux/zalloc.h>
20}
21#include "llvm-c-helpers.h"
22
23extern "C"
24char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name);
25
26using namespace llvm;
27using llvm::symbolize::LLVMSymbolizer;
28
29/*
30 * Allocate a static LLVMSymbolizer, which will live to the end of the program.
31 * Unlike the bfd paths, LLVMSymbolizer has its own cache, so we do not need
32 * to store anything in the dso struct.
33 */
34static LLVMSymbolizer *get_symbolizer()
35{
36 static LLVMSymbolizer *instance = nullptr;
37 if (instance == nullptr) {
38 LLVMSymbolizer::Options opts;
39 /*
40 * LLVM sometimes demangles slightly different from the rest
41 * of the code, and this mismatch can cause new_inline_sym()
42 * to get confused and mark non-inline symbol as inlined
43 * (since the name does not properly match up with base_sym).
44 * Thus, disable the demangling and let the rest of the code
45 * handle it.
46 */
47 opts.Demangle = false;
48 instance = new LLVMSymbolizer(opts);
49 }
50 return instance;
51}
52
53/* Returns 0 on error, 1 on success. */
54static int extract_file_and_line(const DILineInfo &line_info, char **file,
55 unsigned int *line)
56{
57 if (file) {
58 if (line_info.FileName == "<invalid>") {
59 /* Match the convention of libbfd. */
60 *file = nullptr;
61 } else {
62 /* The caller expects to get something it can free(). */
63 *file = strdup(line_info.FileName.c_str());
64 if (*file == nullptr)
65 return 0;
66 }
67 }
68 if (line)
69 *line = line_info.Line;
70 return 1;
71}
72
73extern "C"
74int llvm_addr2line(const char *dso_name, u64 addr,
75 char **file, unsigned int *line,
76 bool unwind_inlines,
77 llvm_a2l_frame **inline_frames)
78{
79 LLVMSymbolizer *symbolizer = get_symbolizer();
80 object::SectionedAddress sectioned_addr = {
81 addr,
82 object::SectionedAddress::UndefSection
83 };
84
85 if (unwind_inlines) {
86 Expected<DIInliningInfo> res_or_err =
87 symbolizer->symbolizeInlinedCode(dso_name,
88 sectioned_addr);
89 if (!res_or_err)
90 return 0;
91 unsigned num_frames = res_or_err->getNumberOfFrames();
92 if (num_frames == 0)
93 return 0;
94
95 if (extract_file_and_line(res_or_err->getFrame(0),
96 file, line) == 0)
97 return 0;
98
99 *inline_frames = (llvm_a2l_frame *)calloc(
100 num_frames, sizeof(**inline_frames));
101 if (*inline_frames == nullptr)
102 return 0;
103
104 for (unsigned i = 0; i < num_frames; ++i) {
105 const DILineInfo &src = res_or_err->getFrame(i);
106
107 llvm_a2l_frame &dst = (*inline_frames)[i];
108 if (src.FileName == "<invalid>")
109 /* Match the convention of libbfd. */
110 dst.filename = nullptr;
111 else
112 dst.filename = strdup(src.FileName.c_str());
113 dst.funcname = strdup(src.FunctionName.c_str());
114 dst.line = src.Line;
115
116 if (dst.filename == nullptr ||
117 dst.funcname == nullptr) {
118 for (unsigned j = 0; j <= i; ++j) {
119 zfree(&(*inline_frames)[j].filename);
120 zfree(&(*inline_frames)[j].funcname);
121 }
122 zfree(inline_frames);
123 return 0;
124 }
125 }
126
127 return num_frames;
128 } else {
129 if (inline_frames)
130 *inline_frames = nullptr;
131
132 Expected<DILineInfo> res_or_err =
133 symbolizer->symbolizeCode(dso_name, sectioned_addr);
134 if (!res_or_err)
135 return 0;
136 return extract_file_and_line(*res_or_err, file, line);
137 }
138}
139
140static char *
141make_symbol_relative_string(struct dso *dso, const char *sym_name,
142 u64 addr, u64 base_addr)
143{
144 if (!strcmp(sym_name, "<invalid>"))
145 return NULL;
146
147 char *demangled = dso__demangle_sym(dso, 0, sym_name);
148 if (base_addr && base_addr != addr) {
149 char buf[256];
150 snprintf(buf, sizeof(buf), "%s+0x%" PRIx64,
151 demangled ? demangled : sym_name, addr - base_addr);
152 free(demangled);
153 return strdup(buf);
154 } else {
155 if (demangled)
156 return demangled;
157 else
158 return strdup(sym_name);
159 }
160}
161
162extern "C"
163char *llvm_name_for_code(struct dso *dso, const char *dso_name, u64 addr)
164{
165 LLVMSymbolizer *symbolizer = get_symbolizer();
166 object::SectionedAddress sectioned_addr = {
167 addr,
168 object::SectionedAddress::UndefSection
169 };
170 Expected<DILineInfo> res_or_err =
171 symbolizer->symbolizeCode(dso_name, sectioned_addr);
172 if (!res_or_err) {
173 return NULL;
174 }
175 return make_symbol_relative_string(
176 dso, res_or_err->FunctionName.c_str(),
177 addr, res_or_err->StartAddress ? *res_or_err->StartAddress : 0);
178}
179
180extern "C"
181char *llvm_name_for_data(struct dso *dso, const char *dso_name, u64 addr)
182{
183 LLVMSymbolizer *symbolizer = get_symbolizer();
184 object::SectionedAddress sectioned_addr = {
185 addr,
186 object::SectionedAddress::UndefSection
187 };
188 Expected<DIGlobal> res_or_err =
189 symbolizer->symbolizeData(dso_name, sectioned_addr);
190 if (!res_or_err) {
191 return NULL;
192 }
193 return make_symbol_relative_string(
194 dso, res_or_err->Name.c_str(),
195 addr, res_or_err->Start);
196}