Commit Graph

6 Commits

Author SHA1 Message Date
Igor Kudrin 657e067bb5 [ARMInstPrinter] Print the target address of a branch instruction
This follows other patches that changed printing immediate values of
branch instructions to target addresses, see D76580 (x86), D76591 (PPC),
D77853 (AArch64).

As observing immediate values might sometimes be useful, they are
printed as comments for branch instructions.

// llvm-objdump -d output (before)
000200b4 <_start>:
   200b4: ff ff ff fa   blx     #-4 <thumb>
000200b8 <thumb>:
   200b8: ff f7 fc ef   blx     #-8 <_start>

// llvm-objdump -d output (after)
000200b4 <_start>:
   200b4: ff ff ff fa   blx     0x200b8 <thumb>         @ imm = #-4
000200b8 <thumb>:
   200b8: ff f7 fc ef   blx     0x200b4 <_start>        @ imm = #-8

// GNU objdump -d.
000200b4 <_start>:
   200b4:       faffffff        blx     200b8 <thumb>
000200b8 <thumb>:
   200b8:       f7ff effc       blx     200b4 <_start>

Differential Revision: https://reviews.llvm.org/D104701
2021-06-30 16:35:28 +07:00
Fangrui Song 011b785505 [ELF] Create readonly PT_LOAD in the presence of a SECTIONS command
This essentially drops the change by r288021 (discussed with Georgii Rymar
and Peter Smith and noted down in the release note of lld 10).

GNU ld>=2.31 enables -z separate-code by default for Linux x86. By
default (in the absence of a PHDRS command) a readonly PT_LOAD is
created, which is different from its traditional behavior.

Not emulating GNU ld's traditional behavior is good for us because it
improves code consistency (we create a readonly PT_LOAD in the absence
of a SECTIONS command).

Users can add --no-rosegment to restore the previous behavior (combined
readonly and read-executable sections in a single RX PT_LOAD).
2020-03-19 19:11:11 -07:00
Fangrui Song f0374e7db2 [test] lld/test/: change llvm-objdump single-dash long options to double-dash options 2020-03-15 17:48:36 -07:00
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
Fangrui Song 5387c2cd17 [llvm-objdump] Print newlines before and after "Disassembly of section ...:"
This improves readability and the behavior is consistent with GNU objdump.

The new test test/tools/llvm-objdump/X86/disassemble-section-name.s
checks we print newlines before and after "Disassembly of section ...:"

Differential Revision: https://reviews.llvm.org/D61127

llvm-svn: 359668
2019-05-01 10:40:48 +00:00
Peter Smith 6ece0ad429 [ELF][ARM] Add support for architecture v6m thunks
ARM Architecture v6m is used by the smallest microcontrollers such as the
cortex-m0. It is Thumb only (no Thumb 2) which prevents it from using the
existing Thumb 2 range extension thunks as these use the Thumb 2 movt/movw
instructions. Range extension thunks are not usually needed for
microcontrollers due to the small amount of flash and ram on the device,
however if code is copied from flash into ram then a range extension thunk
is required to call that code.

This change adds support for v6m range extension thunks. The procedure call
standard APCS permits a thunk to corrupt the intra-procedural scratch
register r12 (referred to as ip in the APCS). Most Thumb instructions do
not permit access to high registers (r8 - r15) so the thunks must spill
some low registers (r0 - r7) to perform the control transfer.

Fixes pr39922

Differential Revision: https://reviews.llvm.org/D55555

llvm-svn: 349337
2018-12-17 10:33:47 +00:00