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 22 static 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 35 int 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 void dso__free_a2l_llvm(struct dso *dso __maybe_unused) 74 { 75 /* Nothing to free. */ 76 } 77 78 #ifdef HAVE_LIBLLVM_SUPPORT 79 static void init_llvm(void) 80 { 81 static bool init; 82 83 if (!init) { 84 LLVMInitializeAllTargetInfos(); 85 LLVMInitializeAllTargetMCs(); 86 LLVMInitializeAllDisassemblers(); 87 init = true; 88 } 89 } 90 91 /* 92 * Whenever LLVM wants to resolve an address into a symbol, it calls this 93 * callback. We don't ever actually _return_ anything (in particular, because 94 * it puts quotation marks around what we return), but we use this as a hint 95 * that there is a branch or PC-relative address in the expression that we 96 * should add some textual annotation for after the instruction. The caller 97 * will use this information to add the actual annotation. 98 */ 99 struct symbol_lookup_storage { 100 u64 branch_addr; 101 u64 pcrel_load_addr; 102 }; 103 104 static const char * 105 symbol_lookup_callback(void *disinfo, uint64_t value, 106 uint64_t *ref_type, 107 uint64_t address __maybe_unused, 108 const char **ref __maybe_unused) 109 { 110 struct symbol_lookup_storage *storage = disinfo; 111 112 if (*ref_type == LLVMDisassembler_ReferenceType_In_Branch) 113 storage->branch_addr = value; 114 else if (*ref_type == LLVMDisassembler_ReferenceType_In_PCrel_Load) 115 storage->pcrel_load_addr = value; 116 *ref_type = LLVMDisassembler_ReferenceType_InOut_None; 117 return NULL; 118 } 119 #endif 120 121 int symbol__disassemble_llvm(const char *filename, struct symbol *sym, 122 struct annotate_args *args __maybe_unused) 123 { 124 #ifdef HAVE_LIBLLVM_SUPPORT 125 struct annotation *notes = symbol__annotation(sym); 126 struct map *map = args->ms.map; 127 struct dso *dso = map__dso(map); 128 u64 start = map__rip_2objdump(map, sym->start); 129 /* Malloc-ed buffer containing instructions read from disk. */ 130 u8 *code_buf = NULL; 131 /* Pointer to code to be disassembled. */ 132 const u8 *buf; 133 u64 buf_len; 134 u64 pc; 135 bool is_64bit; 136 char disasm_buf[2048]; 137 size_t disasm_len; 138 struct disasm_line *dl; 139 LLVMDisasmContextRef disasm = NULL; 140 struct symbol_lookup_storage storage; 141 char *line_storage = NULL; 142 size_t line_storage_len = 0; 143 int ret = -1; 144 145 if (args->options->objdump_path) 146 return -1; 147 148 buf = dso__read_symbol(dso, filename, map, sym, 149 &code_buf, &buf_len, &is_64bit); 150 if (buf == NULL) 151 return errno; 152 153 init_llvm(); 154 if (arch__is(args->arch, "x86")) { 155 const char *triplet = is_64bit ? "x86_64-pc-linux" : "i686-pc-linux"; 156 157 disasm = LLVMCreateDisasm(triplet, &storage, /*tag_type=*/0, 158 /*get_op_info=*/NULL, symbol_lookup_callback); 159 } else { 160 char triplet[64]; 161 162 scnprintf(triplet, sizeof(triplet), "%s-linux-gnu", 163 args->arch->name); 164 disasm = LLVMCreateDisasm(triplet, &storage, /*tag_type=*/0, 165 /*get_op_info=*/NULL, symbol_lookup_callback); 166 } 167 168 if (disasm == NULL) 169 goto err; 170 171 if (args->options->disassembler_style && 172 !strcmp(args->options->disassembler_style, "intel")) 173 LLVMSetDisasmOptions(disasm, 174 LLVMDisassembler_Option_AsmPrinterVariant); 175 176 /* 177 * This needs to be set after AsmPrinterVariant, due to a bug in LLVM; 178 * setting AsmPrinterVariant makes a new instruction printer, making it 179 * forget about the PrintImmHex flag (which is applied before if both 180 * are given to the same call). 181 */ 182 LLVMSetDisasmOptions(disasm, LLVMDisassembler_Option_PrintImmHex); 183 184 /* add the function address and name */ 185 scnprintf(disasm_buf, sizeof(disasm_buf), "%#"PRIx64" <%s>:", 186 start, sym->name); 187 188 args->offset = -1; 189 args->line = disasm_buf; 190 args->line_nr = 0; 191 args->fileloc = NULL; 192 args->ms.sym = sym; 193 194 dl = disasm_line__new(args); 195 if (dl == NULL) 196 goto err; 197 198 annotation_line__add(&dl->al, ¬es->src->source); 199 200 pc = start; 201 for (u64 offset = 0; offset < buf_len; ) { 202 unsigned int ins_len; 203 204 storage.branch_addr = 0; 205 storage.pcrel_load_addr = 0; 206 207 /* 208 * LLVM's API has the code be disassembled as non-const, cast 209 * here as we may be disassembling from mapped read-only memory. 210 */ 211 ins_len = LLVMDisasmInstruction(disasm, (u8 *)(buf + offset), 212 buf_len - offset, pc, 213 disasm_buf, sizeof(disasm_buf)); 214 if (ins_len == 0) 215 goto err; 216 disasm_len = strlen(disasm_buf); 217 218 if (storage.branch_addr != 0) { 219 char *name = llvm_name_for_code(dso, filename, 220 storage.branch_addr); 221 if (name != NULL) { 222 disasm_len += scnprintf(disasm_buf + disasm_len, 223 sizeof(disasm_buf) - 224 disasm_len, 225 " <%s>", name); 226 free(name); 227 } 228 } 229 if (storage.pcrel_load_addr != 0) { 230 char *name = llvm_name_for_data(dso, filename, 231 storage.pcrel_load_addr); 232 disasm_len += scnprintf(disasm_buf + disasm_len, 233 sizeof(disasm_buf) - disasm_len, 234 " # %#"PRIx64, 235 storage.pcrel_load_addr); 236 if (name) { 237 disasm_len += scnprintf(disasm_buf + disasm_len, 238 sizeof(disasm_buf) - 239 disasm_len, 240 " <%s>", name); 241 free(name); 242 } 243 } 244 245 args->offset = offset; 246 args->line = expand_tabs(disasm_buf, &line_storage, 247 &line_storage_len); 248 args->line_nr = 0; 249 args->fileloc = NULL; 250 args->ms.sym = sym; 251 252 llvm_addr2line(filename, pc, &args->fileloc, 253 (unsigned int *)&args->line_nr, false, NULL); 254 255 dl = disasm_line__new(args); 256 if (dl == NULL) 257 goto err; 258 259 annotation_line__add(&dl->al, ¬es->src->source); 260 261 free(args->fileloc); 262 pc += ins_len; 263 offset += ins_len; 264 } 265 266 ret = 0; 267 268 err: 269 LLVMDisasmDispose(disasm); 270 free(code_buf); 271 free(line_storage); 272 return ret; 273 #else // HAVE_LIBLLVM_SUPPORT 274 pr_debug("The LLVM disassembler isn't linked in for %s in %s\n", 275 sym->name, filename); 276 return -1; 277 #endif 278 } 279