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1// SPDX-License-Identifier: GPL-2.0
2#include "llvm.h"
3#include "annotate.h"
4#include "debug.h"
5#include "dso.h"
6#include "map.h"
7#include "namespaces.h"
8#include "srcline.h"
9#include "symbol.h"
10#include <errno.h>
11#include <fcntl.h>
12#include <unistd.h>
13#include <linux/zalloc.h>
14
15#ifdef HAVE_LIBLLVM_SUPPORT
16#include "llvm-c-helpers.h"
17#include <llvm-c/Disassembler.h>
18#include <llvm-c/Target.h>
19#endif
20
21#ifdef HAVE_LIBLLVM_SUPPORT
22static void free_llvm_inline_frames(struct llvm_a2l_frame *inline_frames,
23 int num_frames)
24{
25 if (inline_frames != NULL) {
26 for (int i = 0; i < num_frames; ++i) {
27 zfree(&inline_frames[i].filename);
28 zfree(&inline_frames[i].funcname);
29 }
30 zfree(&inline_frames);
31 }
32}
33#endif
34
35int llvm__addr2line(const char *dso_name __maybe_unused, u64 addr __maybe_unused,
36 char **file __maybe_unused, unsigned int *line __maybe_unused,
37 struct dso *dso __maybe_unused, bool unwind_inlines __maybe_unused,
38 struct inline_node *node __maybe_unused, struct symbol *sym __maybe_unused)
39{
40#ifdef HAVE_LIBLLVM_SUPPORT
41 struct llvm_a2l_frame *inline_frames = NULL;
42 int num_frames = llvm_addr2line(dso_name, addr, file, line,
43 node && unwind_inlines, &inline_frames);
44
45 if (num_frames == 0 || !inline_frames) {
46 /* Error, or we didn't want inlines. */
47 return num_frames;
48 }
49
50 for (int i = 0; i < num_frames; ++i) {
51 struct symbol *inline_sym =
52 new_inline_sym(dso, sym, inline_frames[i].funcname);
53 char *srcline = NULL;
54
55 if (inline_frames[i].filename) {
56 srcline =
57 srcline_from_fileline(inline_frames[i].filename,
58 inline_frames[i].line);
59 }
60 if (inline_list__append(inline_sym, srcline, node) != 0) {
61 free_llvm_inline_frames(inline_frames, num_frames);
62 return 0;
63 }
64 }
65 free_llvm_inline_frames(inline_frames, num_frames);
66
67 return num_frames;
68#else
69 return -1;
70#endif
71}
72
73#ifdef HAVE_LIBLLVM_SUPPORT
74static void init_llvm(void)
75{
76 static bool init;
77
78 if (!init) {
79 LLVMInitializeAllTargetInfos();
80 LLVMInitializeAllTargetMCs();
81 LLVMInitializeAllDisassemblers();
82 init = true;
83 }
84}
85
86/*
87 * Whenever LLVM wants to resolve an address into a symbol, it calls this
88 * callback. We don't ever actually _return_ anything (in particular, because
89 * it puts quotation marks around what we return), but we use this as a hint
90 * that there is a branch or PC-relative address in the expression that we
91 * should add some textual annotation for after the instruction. The caller
92 * will use this information to add the actual annotation.
93 */
94struct symbol_lookup_storage {
95 u64 branch_addr;
96 u64 pcrel_load_addr;
97};
98
99static const char *
100symbol_lookup_callback(void *disinfo, uint64_t value,
101 uint64_t *ref_type,
102 uint64_t address __maybe_unused,
103 const char **ref __maybe_unused)
104{
105 struct symbol_lookup_storage *storage = disinfo;
106
107 if (*ref_type == LLVMDisassembler_ReferenceType_In_Branch)
108 storage->branch_addr = value;
109 else if (*ref_type == LLVMDisassembler_ReferenceType_In_PCrel_Load)
110 storage->pcrel_load_addr = value;
111 *ref_type = LLVMDisassembler_ReferenceType_InOut_None;
112 return NULL;
113}
114#endif
115
116int symbol__disassemble_llvm(const char *filename, struct symbol *sym,
117 struct annotate_args *args __maybe_unused)
118{
119#ifdef HAVE_LIBLLVM_SUPPORT
120 struct annotation *notes = symbol__annotation(sym);
121 struct map *map = args->ms->map;
122 struct dso *dso = map__dso(map);
123 u64 start = map__rip_2objdump(map, sym->start);
124 /* Malloc-ed buffer containing instructions read from disk. */
125 u8 *code_buf = NULL;
126 /* Pointer to code to be disassembled. */
127 const u8 *buf;
128 u64 buf_len;
129 u64 pc;
130 bool is_64bit;
131 char disasm_buf[2048];
132 size_t disasm_len;
133 struct disasm_line *dl;
134 LLVMDisasmContextRef disasm = NULL;
135 struct symbol_lookup_storage storage;
136 char *line_storage = NULL;
137 size_t line_storage_len = 0;
138 int ret = -1;
139
140 if (args->options->objdump_path)
141 return -1;
142
143 buf = dso__read_symbol(dso, filename, map, sym,
144 &code_buf, &buf_len, &is_64bit);
145 if (buf == NULL)
146 return errno;
147
148 init_llvm();
149 if (arch__is_x86(args->arch)) {
150 const char *triplet = is_64bit ? "x86_64-pc-linux" : "i686-pc-linux";
151
152 disasm = LLVMCreateDisasm(triplet, &storage, /*tag_type=*/0,
153 /*get_op_info=*/NULL, symbol_lookup_callback);
154 } else {
155 char triplet[64];
156 const char *features = NULL;
157
158 scnprintf(triplet, sizeof(triplet), "%s-linux-gnu",
159 args->arch->name);
160 if (args->arch->id.e_machine == EM_AARCH64)
161 features = "+all";
162 disasm = LLVMCreateDisasmCPUFeatures(triplet, /*cpu=*/"",
163 features, &storage,
164 /*tag_type=*/0,
165 /*get_op_info=*/NULL,
166 symbol_lookup_callback);
167 }
168
169 if (disasm == NULL)
170 goto err;
171
172 if (args->options->disassembler_style &&
173 !strcmp(args->options->disassembler_style, "intel"))
174 LLVMSetDisasmOptions(disasm,
175 LLVMDisassembler_Option_AsmPrinterVariant);
176
177 /*
178 * This needs to be set after AsmPrinterVariant, due to a bug in LLVM;
179 * setting AsmPrinterVariant makes a new instruction printer, making it
180 * forget about the PrintImmHex flag (which is applied before if both
181 * are given to the same call).
182 */
183 LLVMSetDisasmOptions(disasm, LLVMDisassembler_Option_PrintImmHex);
184
185 /* add the function address and name */
186 scnprintf(disasm_buf, sizeof(disasm_buf), "%#"PRIx64" <%s>:",
187 start, sym->name);
188
189 args->offset = -1;
190 args->line = disasm_buf;
191 args->line_nr = 0;
192 args->fileloc = NULL;
193 args->ms->sym = sym;
194
195 dl = disasm_line__new(args);
196 if (dl == NULL)
197 goto err;
198
199 annotation_line__add(&dl->al, &notes->src->source);
200
201 pc = start;
202 for (u64 offset = 0; offset < buf_len; ) {
203 unsigned int ins_len;
204
205 storage.branch_addr = 0;
206 storage.pcrel_load_addr = 0;
207
208 /*
209 * LLVM's API has the code be disassembled as non-const, cast
210 * here as we may be disassembling from mapped read-only memory.
211 */
212 ins_len = LLVMDisasmInstruction(disasm, (u8 *)(buf + offset),
213 buf_len - offset, pc,
214 disasm_buf, sizeof(disasm_buf));
215 if (ins_len == 0)
216 goto err;
217 disasm_len = strlen(disasm_buf);
218
219 if (storage.branch_addr != 0) {
220 char *name = llvm_name_for_code(dso, filename,
221 storage.branch_addr);
222 if (name != NULL) {
223 disasm_len += scnprintf(disasm_buf + disasm_len,
224 sizeof(disasm_buf) -
225 disasm_len,
226 " <%s>", name);
227 free(name);
228 }
229 }
230 if (storage.pcrel_load_addr != 0) {
231 char *name = llvm_name_for_data(dso, filename,
232 storage.pcrel_load_addr);
233 disasm_len += scnprintf(disasm_buf + disasm_len,
234 sizeof(disasm_buf) - disasm_len,
235 " # %#"PRIx64,
236 storage.pcrel_load_addr);
237 if (name) {
238 disasm_len += scnprintf(disasm_buf + disasm_len,
239 sizeof(disasm_buf) -
240 disasm_len,
241 " <%s>", name);
242 free(name);
243 }
244 }
245
246 args->offset = offset;
247 args->line = expand_tabs(disasm_buf, &line_storage,
248 &line_storage_len);
249 args->line_nr = 0;
250 args->fileloc = NULL;
251 args->ms->sym = sym;
252
253 llvm_addr2line(filename, pc, &args->fileloc,
254 (unsigned int *)&args->line_nr, false, NULL);
255
256 dl = disasm_line__new(args);
257 if (dl == NULL)
258 goto err;
259
260 annotation_line__add(&dl->al, &notes->src->source);
261
262 free(args->fileloc);
263 pc += ins_len;
264 offset += ins_len;
265 }
266
267 ret = 0;
268
269err:
270 LLVMDisasmDispose(disasm);
271 free(code_buf);
272 free(line_storage);
273 return ret;
274#else // HAVE_LIBLLVM_SUPPORT
275 pr_debug("The LLVM disassembler isn't linked in for %s in %s\n",
276 sym->name, filename);
277 return -1;
278#endif
279}