Commit Graph

6 Commits

Author SHA1 Message Date
Fangrui Song f17e7df04a [ELF][test] Delete unneeded --triple=thumb* from llvm-objdump RUN lines 2021-07-28 12:47:12 -07:00
Fangrui Song ac46bc35e9 [ELF][test] Fix some llvm-objdump RUN lines which don't actually test anything 2020-08-19 22:49:04 -07:00
Peter Smith da74537e87 [LLD][ELF][ARM] use .reloc directive for Thumb assembler tests
In the near future llvm-mc will resolve the fixups that generate
R_ARM_THUMB_PC8 and R_ARM_THUMB_PC12 at assembly time (see comments in
D72892), and forbid inter-section references. Change the LLD tests for
these relocations to use .inst and .reloc to avoid LLD tests failing when
this happens. The tests generate the same instructions, relocations
and symbols.

I will need to make equivalent changes for D75349 Arm equivalent
relocations, but this is still in review so these don't need changing
before llvm-mc.

Differential Revision: https://reviews.llvm.org/D77200
2020-04-03 11:44:31 +01:00
Fangrui Song 71e2ca6e32 [llvm-objdump] -d: print `00000000 <foo>:` instead of `00000000 foo:`
The new behavior matches GNU objdump. A pair of angle brackets makes tests slightly easier.

`.foo:` is not unique and thus cannot be used in a `CHECK-LABEL:` directive.
Without `-LABEL`, the CHECK line can match the `Disassembly of section`
line and causes the next `CHECK-NEXT:` to fail.

```
Disassembly of section .foo:

0000000000001634 .foo:
```

Bdragon: <> has metalinguistic connotation. it just "feels right"

Reviewed By: rupprecht

Differential Revision: https://reviews.llvm.org/D75713
2020-03-05 18:05:28 -08:00
Peter Smith 1b025665c9 [ELF][LLD][ARM] Add missing REQUIRES: arm to tests
Fix buildbots that don't build ARM backend.
2020-02-28 11:46:01 +00:00
Peter Smith 6b035b607f [LLD][ELF][ARM] Implement Thumb pc-relative relocations for adr and ldr
MC will now output the R_ARM_THM_PC8, R_ARM_THM_PC12 and
R_ARM_THM_PREL_11_0 relocations. These are short-ranged relocations that
are used to implement the adr rd, literal and ldr rd, literal pseudo
instructions.

The instructions use a new RelExpr called R_ARM_PCA in order to calculate
the required S + A - Pa expression, where Pa is AlignDown(P, 4) as the
instructions add their immediate to AlignDown(PC, 4). We also do not want
these relocations to generate or resolve against a PLT entry as the range
of these relocations is so short they would never reach.

The R_ARM_THM_PC8 has a special encoding convention for the relocation
addend, the immediate field is unsigned, yet the addend must be -4 to
account for the Thumb PC bias. The ABI (not the architecture) uses the
convention that the 8-byte immediate of 0xff represents -4.

Differential Revision: https://reviews.llvm.org/D75042
2020-02-28 11:29:29 +00:00