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>
18 extern "C" {
19 #include <linux/zalloc.h>
20 }
21 #include "symbol_conf.h"
22 #include "llvm-c-helpers.h"
23
24 extern "C"
25 char *dso__demangle_sym(struct dso *dso, int kmodule, const char *elf_name);
26
27 using namespace llvm;
28 using llvm::symbolize::LLVMSymbolizer;
29
30 /*
31 * Allocate a static LLVMSymbolizer, which will live to the end of the program.
32 * Unlike the bfd paths, LLVMSymbolizer has its own cache, so we do not need
33 * to store anything in the dso struct.
34 */
35 static LLVMSymbolizer *get_symbolizer()
36 {
37 static LLVMSymbolizer *instance = nullptr;
38 if (instance == nullptr) {
39 LLVMSymbolizer::Options opts;
40 /*
41 * LLVM sometimes demangles slightly different from the rest
42 * of the code, and this mismatch can cause new_inline_sym()
43 * to get confused and mark non-inline symbol as inlined
44 * (since the name does not properly match up with base_sym).
45 * Thus, disable the demangling and let the rest of the code
46 * handle it.
47 */
48 opts.Demangle = false;
49 instance = new LLVMSymbolizer(opts);
50 }
51 return instance;
52 }
53
54 /* Returns 0 on error, 1 on success. */
55 static int extract_file_and_line(const DILineInfo &line_info, char **file,
56 unsigned int *line)
57 {
58 if (file) {
59 if (line_info.FileName == "<invalid>") {
60 /* Match the convention of libbfd. */
61 *file = nullptr;
62 } else {
63 /* The caller expects to get something it can free(). */
64 *file = strdup(line_info.FileName.c_str());
65 if (*file == nullptr)
66 return 0;
67 }
68 }
69 if (line)
70 *line = line_info.Line;
71 return 1;
72 }
73
74 extern "C"
75 int llvm_addr2line(const char *dso_name, u64 addr,
76 char **file, unsigned int *line,
77 bool unwind_inlines,
78 llvm_a2l_frame **inline_frames)
79 {
80 LLVMSymbolizer *symbolizer = get_symbolizer();
81 object::SectionedAddress sectioned_addr = {
82 addr,
83 object::SectionedAddress::UndefSection
84 };
85
86 if (unwind_inlines) {
87 Expected<DIInliningInfo> res_or_err =
88 symbolizer->symbolizeInlinedCode(dso_name,
89 sectioned_addr);
90 if (!res_or_err)
91 return 0;
92 unsigned num_frames = res_or_err->getNumberOfFrames();
93 if (num_frames == 0)
94 return 0;
95
96 if (extract_file_and_line(res_or_err->getFrame(0),
97 file, line) == 0)
98 return 0;
99
100 *inline_frames = (llvm_a2l_frame *)calloc(
101 num_frames, sizeof(**inline_frames));
102 if (*inline_frames == nullptr)
103 return 0;
104
105 for (unsigned i = 0; i < num_frames; ++i) {
106 const DILineInfo &src = res_or_err->getFrame(i);
107
108 llvm_a2l_frame &dst = (*inline_frames)[i];
109 if (src.FileName == "<invalid>")
110 /* Match the convention of libbfd. */
111 dst.filename = nullptr;
112 else
113 dst.filename = strdup(src.FileName.c_str());
114 dst.funcname = strdup(src.FunctionName.c_str());
115 dst.line = src.Line;
116
117 if (dst.filename == nullptr ||
118 dst.funcname == nullptr) {
119 for (unsigned j = 0; j <= i; ++j) {
120 zfree(&(*inline_frames)[j].filename);
121 zfree(&(*inline_frames)[j].funcname);
122 }
123 zfree(inline_frames);
124 return 0;
125 }
126 }
127
128 return num_frames;
129 } else {
130 if (inline_frames)
131 *inline_frames = nullptr;
132
133 Expected<DILineInfo> res_or_err =
134 symbolizer->symbolizeCode(dso_name, sectioned_addr);
135 if (!res_or_err)
136 return 0;
137 return extract_file_and_line(*res_or_err, file, line);
138 }
139 }
140
141 static char *
142 make_symbol_relative_string(struct dso *dso, const char *sym_name,
143 u64 addr, u64 base_addr)
144 {
145 if (!strcmp(sym_name, "<invalid>"))
146 return NULL;
147
148 char *demangled = dso__demangle_sym(dso, 0, sym_name);
149 if (base_addr && base_addr != addr) {
150 char buf[256];
151 snprintf(buf, sizeof(buf), "%s+0x%" PRIx64,
152 demangled ? demangled : sym_name, addr - base_addr);
153 free(demangled);
154 return strdup(buf);
155 } else {
156 if (demangled)
157 return demangled;
158 else
159 return strdup(sym_name);
160 }
161 }
162
163 extern "C"
164 char *llvm_name_for_code(struct dso *dso, const char *dso_name, u64 addr)
165 {
166 LLVMSymbolizer *symbolizer = get_symbolizer();
167 object::SectionedAddress sectioned_addr = {
168 addr,
169 object::SectionedAddress::UndefSection
170 };
171 Expected<DILineInfo> res_or_err =
172 symbolizer->symbolizeCode(dso_name, sectioned_addr);
173 if (!res_or_err) {
174 return NULL;
175 }
176 return make_symbol_relative_string(
177 dso, res_or_err->FunctionName.c_str(),
178 addr, res_or_err->StartAddress ? *res_or_err->StartAddress : 0);
179 }
180
181 extern "C"
182 char *llvm_name_for_data(struct dso *dso, const char *dso_name, u64 addr)
183 {
184 LLVMSymbolizer *symbolizer = get_symbolizer();
185 object::SectionedAddress sectioned_addr = {
186 addr,
187 object::SectionedAddress::UndefSection
188 };
189 Expected<DIGlobal> res_or_err =
190 symbolizer->symbolizeData(dso_name, sectioned_addr);
191 if (!res_or_err) {
192 return NULL;
193 }
194 return make_symbol_relative_string(
195 dso, res_or_err->Name.c_str(),
196 addr, res_or_err->Start);
197 }
198
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