test/MC/Mips/sort-relocation-table.s

   1 # RUN: llvm-mc -filetype=obj -arch mipsel %s | llvm-readobj -r | FileCheck %s
   2
   3 # Test the order of records in the relocation table.
   4 #
   5 # MIPS has a few relocations that have an AHL component in the expression used
   6 # to evaluate them. This AHL component is an addend with the same number of
   7 # bits as a symbol value but not all of our ABI's are able to supply a
   8 # sufficiently sized addend in a single relocation.
   9 #
  10 # The O32 ABI for example, uses REL relocations which store the addend in the
  11 # section data. All the relocations with AHL components affect 16-bit fields
  12 # so the addend is limited to 16-bit. This ABI resolves the limitation by
  13 # linking relocations (e.g. R_MIPS_HI16 and R_MIPS_LO16) and distributing the
  14 # addend between the linked relocations. The ABI mandates that such relocations
  15 # must be next to each other in a particular order (e.g. R_MIPS_HI16 must be
  16 # followed by a matching R_MIPS_LO16) but the rule is less strict in practice.
  17 #
  18 # See MipsELFObjectWriter.cpp for a full description of the rules.
  19 #
  20 # TODO: Add mips16 and micromips tests.
  21
  22 # HILO 1: HI/LO already match
  23         .section .mips_hilo_1, "ax", @progbits
  24         lui $2, %hi(sym1)
  25         addiu $2, $2, %lo(sym1)
  26
  27 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_1 {
  28 # CHECK-NEXT:    0x0 R_MIPS_HI16 sym1
  29 # CHECK-NEXT:    0x4 R_MIPS_LO16 sym1
  30 # CHECK-NEXT:  }
  31
  32 # HILO 2: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
  33         .section .mips_hilo_2, "ax", @progbits
  34         addiu $2, $2, %lo(sym1)
  35         lui $2, %hi(sym1)
  36
  37 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_2 {
  38 # CHECK-NEXT:    0x4 R_MIPS_HI16 sym1
  39 # CHECK-NEXT:    0x0 R_MIPS_LO16 sym1
  40 # CHECK-NEXT:  }
  41
  42 # HILO 3: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
  43 #         The second relocation matches if the symbol is the same.
  44         .section .mips_hilo_3, "ax", @progbits
  45         addiu $2, $2, %lo(sym1)
  46         lui $2, %hi(sym2)
  47         addiu $2, $2, %lo(sym2)
  48         lui $2, %hi(sym1)
  49
  50 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_3 {
  51 # CHECK-NEXT:    0xC R_MIPS_HI16 sym1
  52 # CHECK-NEXT:    0x0 R_MIPS_LO16 sym1
  53 # CHECK-NEXT:    0x4 R_MIPS_HI16 sym2
  54 # CHECK-NEXT:    0x8 R_MIPS_LO16 sym2
  55 # CHECK-NEXT:  }
  56
  57 # HILO 3b: Same as 3 but a different starting order.
  58         .section .mips_hilo_3b, "ax", @progbits
  59         addiu $2, $2, %lo(sym1)
  60         lui $2, %hi(sym1)
  61         addiu $2, $2, %lo(sym2)
  62         lui $2, %hi(sym2)
  63
  64 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_3b {
  65 # CHECK-NEXT:    0x4 R_MIPS_HI16 sym1
  66 # CHECK-NEXT:    0x0 R_MIPS_LO16 sym1
  67 # CHECK-NEXT:    0xC R_MIPS_HI16 sym2
  68 # CHECK-NEXT:    0x8 R_MIPS_LO16 sym2
  69 # CHECK-NEXT:  }
  70
  71 # HILO 4: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
  72 #         The second relocation matches if the symbol is the same and the
  73 #         offset is the same.
  74         .section .mips_hilo_4, "ax", @progbits
  75         addiu $2, $2, %lo(sym1)
  76         addiu $2, $2, %lo(sym1+4)
  77         lui $2, %hi(sym1+4)
  78         lui $2, %hi(sym1)
  79
  80 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_4 {
  81 # CHECK-NEXT:    0xC R_MIPS_HI16 sym1
  82 # CHECK-NEXT:    0x0 R_MIPS_LO16 sym1
  83 # CHECK-NEXT:    0x8 R_MIPS_HI16 sym1
  84 # CHECK-NEXT:    0x4 R_MIPS_LO16 sym1
  85 # CHECK-NEXT:  }
  86
  87 # HILO 5: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
  88 #         The second relocation matches if the symbol is the same and the
  89 #         offset is greater or equal. Exact matches are preferred so both
  90 #         R_MIPS_HI16's match the same R_MIPS_LO16.
  91         .section .mips_hilo_5, "ax", @progbits
  92         lui $2, %hi(sym1)
  93         lui $2, %hi(sym1)
  94         addiu $2, $2, %lo(sym1+1)
  95         addiu $2, $2, %lo(sym1)
  96
  97 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_5 {
  98 # CHECK-NEXT:    0x8 R_MIPS_LO16 sym1
  99 # CHECK-NEXT:    0x0 R_MIPS_HI16 sym1
 100 # CHECK-NEXT:    0x4 R_MIPS_HI16 sym1
 101 # CHECK-NEXT:    0xC R_MIPS_LO16 sym1
 102 # CHECK-NEXT:  }
 103
 104 # HILO 6: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
 105 #         The second relocation matches if the symbol is the same and the
 106 #         offset is greater or equal. Smaller offsets are preferred so both
 107 #         R_MIPS_HI16's still match the same R_MIPS_LO16.
 108         .section .mips_hilo_6, "ax", @progbits
 109         lui $2, %hi(sym1)
 110         lui $2, %hi(sym1)
 111         addiu $2, $2, %lo(sym1+2)
 112         addiu $2, $2, %lo(sym1+1)
 113
 114 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_6 {
 115 # CHECK-NEXT:    0x8 R_MIPS_LO16 sym1
 116 # CHECK-NEXT:    0x0 R_MIPS_HI16 sym1
 117 # CHECK-NEXT:    0x4 R_MIPS_HI16 sym1
 118 # CHECK-NEXT:    0xC R_MIPS_LO16 sym1
 119 # CHECK-NEXT:  }
 120
 121 # HILO 7: R_MIPS_HI16 must be followed by a matching R_MIPS_LO16.
 122 #         The second relocation matches if the symbol is the same and the
 123 #         offset is greater or equal so that the carry bit is correct. The two
 124 #         R_MIPS_HI16's therefore match different R_MIPS_LO16's.
 125         .section .mips_hilo_7, "ax", @progbits
 126         addiu $2, $2, %lo(sym1+1)
 127         addiu $2, $2, %lo(sym1+6)
 128         lui $2, %hi(sym1+4)
 129         lui $2, %hi(sym1)
 130
 131 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_7 {
 132 # CHECK-NEXT:    0xC R_MIPS_HI16 sym1
 133 # CHECK-NEXT:    0x0 R_MIPS_LO16 sym1
 134 # CHECK-NEXT:    0x8 R_MIPS_HI16 sym1
 135 # CHECK-NEXT:    0x4 R_MIPS_LO16 sym1
 136 # CHECK-NEXT:  }
 137
 138 # HILO 8: R_MIPS_LO16's may be orphaned.
 139         .section .mips_hilo_8, "ax", @progbits
 140         lw $2, %lo(sym1)
 141
 142 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_8 {
 143 # CHECK-NEXT:    0x0 R_MIPS_LO16 sym1
 144 # CHECK-NEXT:  }
 145
 146 # HILO 8b: Another example of 8. The R_MIPS_LO16 at 0x4 is orphaned.
 147         .section .mips_hilo_8b, "ax", @progbits
 148         lw $2, %lo(sym1)
 149         lw $2, %lo(sym1)
 150         lui $2, %hi(sym1)
 151
 152 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_8b {
 153 # CHECK-NEXT:    0x8 R_MIPS_HI16 sym1
 154 # CHECK-NEXT:    0x0 R_MIPS_LO16 sym1
 155 # CHECK-NEXT:    0x4 R_MIPS_LO16 sym1
 156 # CHECK-NEXT:  }
 157
 158 # HILO 9: R_MIPS_HI16's don't need a matching R_MIPS_LO16 to immediately follow
 159 #         so long as there is one after the R_MIPS_HI16 somewhere. This isn't
 160 #         permitted by the ABI specification but has been allowed in practice
 161 #         for a very long time. The R_MIPS_HI16's should be ordered by the
 162 #         address they affect for purely cosmetic reasons.
 163         .section .mips_hilo_9, "ax", @progbits
 164         lw $2, %lo(sym1)
 165         lui $2, %hi(sym1)
 166         lui $2, %hi(sym1)
 167
 168 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_9 {
 169 # CHECK-NEXT:    0x4 R_MIPS_HI16 sym1
 170 # CHECK-NEXT:    0x8 R_MIPS_HI16 sym1
 171 # CHECK-NEXT:    0x0 R_MIPS_LO16 sym1
 172 # CHECK-NEXT:  }
 173
 174 # HILO 10: R_MIPS_HI16's must have a matching R_MIPS_LO16 somewhere though.
 175 #          When this is impossible we have two possible bad behaviours
 176 #          depending on the linker implementation:
 177 #          * The linker silently computes the wrong value using a partially
 178 #            matching R_MIPS_LO16.
 179 #          * The linker rejects the relocation table as invalid.
 180 #          The latter is preferable since it's far easier to detect and debug so
 181 #          check that we encourage this behaviour by putting invalid
 182 #          R_MIPS_HI16's at the end of the relocation table where the risk of a
 183 #          partial match is very low.
 184         .section .mips_hilo_10, "ax", @progbits
 185         lui $2, %hi(sym1)
 186         lw $2, %lo(sym1)
 187         lui $2, %hi(sym2)
 188         lui $2, %hi(sym3)
 189         lw $2, %lo(sym3)
 190
 191 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_hilo_10 {
 192 # CHECK-NEXT:    0x0 R_MIPS_HI16 sym1
 193 # CHECK-NEXT:    0x4 R_MIPS_LO16 sym1
 194 # CHECK-NEXT:    0xC R_MIPS_HI16 sym3
 195 # CHECK-NEXT:    0x10 R_MIPS_LO16 sym3
 196 # CHECK-NEXT:    0x8 R_MIPS_HI16 sym2
 197 # CHECK-NEXT:  }
 198
 199 # Now do the same tests for GOT/LO.
 200 # The rules only apply to R_MIPS_GOT16 on local symbols which are also
 201 # rewritten into section relative relocations.
 202
 203 # GOTLO 1: GOT/LO already match
 204         .section .mips_gotlo_1, "ax", @progbits
 205         lui $2, %got(local1)
 206         addiu $2, $2, %lo(local1)
 207
 208 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_1 {
 209 # CHECK-NEXT:    0x0 R_MIPS_GOT16 .text
 210 # CHECK-NEXT:    0x4 R_MIPS_LO16 .text
 211 # CHECK-NEXT:  }
 212
 213 # GOTLO 2: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
 214         .section .mips_gotlo_2, "ax", @progbits
 215         addiu $2, $2, %lo(local1)
 216         lui $2, %got(local1)
 217
 218 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_2 {
 219 # CHECK-NEXT:    0x4 R_MIPS_GOT16 .text
 220 # CHECK-NEXT:    0x0 R_MIPS_LO16 .text
 221 # CHECK-NEXT:  }
 222
 223 # GOTLO 3: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
 224 #          The second relocation matches if the symbol is the same.
 225         .section .mips_gotlo_3, "ax", @progbits
 226         addiu $2, $2, %lo(local1)
 227         lui $2, %got(local2)
 228         addiu $2, $2, %lo(local2)
 229         lui $2, %got(local1)
 230
 231 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_3 {
 232 # CHECK-NEXT:    0xC R_MIPS_GOT16 .text
 233 # CHECK-NEXT:    0x0 R_MIPS_LO16 .text
 234 # CHECK-NEXT:    0x4 R_MIPS_GOT16 .text
 235 # CHECK-NEXT:    0x8 R_MIPS_LO16 .text
 236 # CHECK-NEXT:  }
 237
 238 # GOTLO 3b: Same as 3 but a different starting order.
 239         .section .mips_gotlo_3b, "ax", @progbits
 240         addiu $2, $2, %lo(local1)
 241         lui $2, %got(local1)
 242         addiu $2, $2, %lo(local2)
 243         lui $2, %got(local2)
 244
 245 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_3b {
 246 # CHECK-NEXT:    0x4 R_MIPS_GOT16 .text
 247 # CHECK-NEXT:    0x0 R_MIPS_LO16 .text
 248 # CHECK-NEXT:    0xC R_MIPS_GOT16 .text
 249 # CHECK-NEXT:    0x8 R_MIPS_LO16 .text
 250 # CHECK-NEXT:  }
 251
 252 # GOTLO 4: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
 253 #          The second relocation matches if the symbol is the same and the
 254 #          offset is the same.
 255         .section .mips_gotlo_4, "ax", @progbits
 256         addiu $2, $2, %lo(local1)
 257         addiu $2, $2, %lo(local1+4)
 258         lui $2, %got(local1+4)
 259         lui $2, %got(local1)
 260
 261 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_4 {
 262 # CHECK-NEXT:    0xC R_MIPS_GOT16 .text
 263 # CHECK-NEXT:    0x0 R_MIPS_LO16 .text
 264 # CHECK-NEXT:    0x8 R_MIPS_GOT16 .text
 265 # CHECK-NEXT:    0x4 R_MIPS_LO16 .text
 266 # CHECK-NEXT:  }
 267
 268 # GOTLO 5: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
 269 #          The second relocation matches if the symbol is the same and the
 270 #          offset is greater or equal. Exact matches are preferred so both
 271 #          R_MIPS_GOT16's match the same R_MIPS_LO16.
 272         .section .mips_gotlo_5, "ax", @progbits
 273         lui $2, %got(local1)
 274         lui $2, %got(local1)
 275         addiu $2, $2, %lo(local1+1)
 276         addiu $2, $2, %lo(local1)
 277
 278 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_5 {
 279 # CHECK-NEXT:    0x8 R_MIPS_LO16 .text
 280 # CHECK-NEXT:    0x0 R_MIPS_GOT16 .text
 281 # CHECK-NEXT:    0x4 R_MIPS_GOT16 .text
 282 # CHECK-NEXT:    0xC R_MIPS_LO16 .text
 283 # CHECK-NEXT:  }
 284
 285 # GOTLO 6: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
 286 #          The second relocation matches if the symbol is the same and the
 287 #          offset is greater or equal. Smaller offsets are preferred so both
 288 #          R_MIPS_GOT16's still match the same R_MIPS_LO16.
 289         .section .mips_gotlo_6, "ax", @progbits
 290         lui $2, %got(local1)
 291         lui $2, %got(local1)
 292         addiu $2, $2, %lo(local1+2)
 293         addiu $2, $2, %lo(local1+1)
 294
 295 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_6 {
 296 # CHECK-NEXT:    0x8 R_MIPS_LO16 .text
 297 # CHECK-NEXT:    0x0 R_MIPS_GOT16 .text
 298 # CHECK-NEXT:    0x4 R_MIPS_GOT16 .text
 299 # CHECK-NEXT:    0xC R_MIPS_LO16 .text
 300 # CHECK-NEXT:  }
 301
 302 # GOTLO 7: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
 303 #          The second relocation matches if the symbol is the same and the
 304 #          offset is greater or equal so that the carry bit is correct. The two
 305 #          R_MIPS_GOT16's therefore match different R_MIPS_LO16's.
 306         .section .mips_gotlo_7, "ax", @progbits
 307         addiu $2, $2, %lo(local1+1)
 308         addiu $2, $2, %lo(local1+6)
 309         lui $2, %got(local1+4)
 310         lui $2, %got(local1)
 311
 312 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_7 {
 313 # CHECK-NEXT:    0xC R_MIPS_GOT16 .text
 314 # CHECK-NEXT:    0x0 R_MIPS_LO16 .text
 315 # CHECK-NEXT:    0x8 R_MIPS_GOT16 .text
 316 # CHECK-NEXT:    0x4 R_MIPS_LO16 .text
 317 # CHECK-NEXT:  }
 318
 319 # GOTLO 8: R_MIPS_LO16's may be orphaned.
 320         .section .mips_gotlo_8, "ax", @progbits
 321         lw $2, %lo(local1)
 322
 323 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_8 {
 324 # CHECK-NEXT:    0x0 R_MIPS_LO16 .text
 325 # CHECK-NEXT:  }
 326
 327 # GOTLO 8b: Another example of 8. The R_MIPS_LO16 at 0x4 is orphaned.
 328         .section .mips_gotlo_8b, "ax", @progbits
 329         lw $2, %lo(local1)
 330         lw $2, %lo(local1)
 331         lui $2, %got(local1)
 332
 333 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_8b {
 334 # CHECK-NEXT:    0x8 R_MIPS_GOT16 .text
 335 # CHECK-NEXT:    0x0 R_MIPS_LO16 .text
 336 # CHECK-NEXT:    0x4 R_MIPS_LO16 .text
 337 # CHECK-NEXT:  }
 338
 339 # GOTLO 9: R_MIPS_GOT16's don't need a matching R_MIPS_LO16 to immediately
 340 #          follow so long as there is one after the R_MIPS_GOT16 somewhere.
 341 #          This isn't permitted by the ABI specification but has been allowed
 342 #          in practice for a very long time. The R_MIPS_GOT16's should be
 343 #          ordered by the address they affect for purely cosmetic reasons.
 344         .section .mips_gotlo_9, "ax", @progbits
 345         lw $2, %lo(local1)
 346         lui $2, %got(local1)
 347         lui $2, %got(local1)
 348
 349 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_9 {
 350 # CHECK-NEXT:    0x4 R_MIPS_GOT16 .text
 351 # CHECK-NEXT:    0x8 R_MIPS_GOT16 .text
 352 # CHECK-NEXT:    0x0 R_MIPS_LO16 .text
 353 # CHECK-NEXT:  }
 354
 355 # GOTLO 10: R_MIPS_GOT16's must have a matching R_MIPS_LO16 somewhere though.
 356 #           When this is impossible we have two possible bad behaviours
 357 #           depending on the linker implementation:
 358 #           * The linker silently computes the wrong value using a partially
 359 #             matching R_MIPS_LO16.
 360 #           * The linker rejects the relocation table as invalid.
 361 #           The latter is preferable since it's far easier to detect and debug
 362 #           so check that we encourage this behaviour by putting invalid
 363 #           R_MIPS_GOT16's at the end of the relocation table where the risk of
 364 #           a partial match is very low.
 365         .section .mips_gotlo_10, "ax", @progbits
 366         lui $2, %got(local1)
 367         lw $2, %lo(local1)
 368         lui $2, %got(local2)
 369         lui $2, %got(local3)
 370         lw $2, %lo(local3)
 371
 372 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_gotlo_10 {
 373 # CHECK-NEXT:    0x0 R_MIPS_GOT16 .text
 374 # CHECK-NEXT:    0x4 R_MIPS_LO16 .text
 375 # CHECK-NEXT:    0xC R_MIPS_GOT16 .text
 376 # CHECK-NEXT:    0x10 R_MIPS_LO16 .text
 377 # CHECK-NEXT:    0x8 R_MIPS_GOT16 .text
 378 # CHECK-NEXT:  }
 379
 380 # Finally, do test 2 for R_MIPS_GOT16 on external symbols to prove they are
 381 # exempt from the rules for local symbols.
 382
 383 # External GOTLO 2: R_MIPS_GOT16 must be followed by a matching R_MIPS_LO16.
 384         .section .mips_ext_gotlo_2, "ax", @progbits
 385         addiu $2, $2, %lo(sym1)
 386         lui $2, %got(sym1)
 387
 388 # CHECK-LABEL: Section ({{[0-9]+}}) .rel.mips_ext_gotlo_2 {
 389 # CHECK-NEXT:    0x0 R_MIPS_LO16 sym1
 390 # CHECK-NEXT:    0x4 R_MIPS_GOT16 sym1
 391 # CHECK-NEXT:  }
 392
 393 # Define some local symbols.
 394         .text
 395         nop
 396 local1: nop
 397 local2: nop
 398 local3: nop