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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	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	ea99ce5e9b	[ELF][ARM] Implement --fix-cortex-a8 to fix erratum 657417 The --fix-cortex-a8 option implements a linker workaround for the coretex-a8 erratum 657417. A summary of the erratum conditions is: - A 32-bit Thumb-2 branch instruction B.w, Bcc.w, BL, BLX spans two 4KiB regions. - The destination of the branch is to the first 4KiB region. - The instruction before the branch is a 32-bit Thumb-2 non-branch instruction. The linker fix is to redirect the branch to a patch not in the first 4KiB region. The patch forwards the branch on to its target. The cortex-a8, is an old CPU, with the first implementation of this workaround in ld.bfd appearing in 2009. The cortex-a8 has been used in early Android Phones and there are some critical applications that still need to run on a cortex-a8 that have the erratum. The patch is applied roughly 10 times on LLD and 20 on Clang when they are built with --fix-cortex-a8 on an Arm system. The formal erratum description is avaliable in the ARM Core Cortex-A8 (AT400/AT401) Errata Notice document. This is available from Arm on request but it seems to be findable via a web search. Differential Revision: https://reviews.llvm.org/D67284 llvm-svn: 371965	2019-09-16 09:38:38 +00:00

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

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

ea99ce5e9b

[ELF][ARM] Implement --fix-cortex-a8 to fix erratum 657417

The --fix-cortex-a8 option implements a linker workaround for the
coretex-a8 erratum 657417. A summary of the erratum conditions is:
- A 32-bit Thumb-2 branch instruction B.w, Bcc.w, BL, BLX spans two
4KiB regions.
- The destination of the branch is to the first 4KiB region.
- The instruction before the branch is a 32-bit Thumb-2 non-branch
instruction.

The linker fix is to redirect the branch to a patch not in the first
4KiB region. The patch forwards the branch on to its target.

The cortex-a8, is an old CPU, with the first implementation of this
workaround in ld.bfd appearing in 2009. The cortex-a8 has been used in
early Android Phones and there are some critical applications that still
need to run on a cortex-a8 that have the erratum. The patch is applied
roughly 10 times on LLD and 20 on Clang when they are built with
--fix-cortex-a8 on an Arm system.

The formal erratum description is avaliable in the ARM Core Cortex-A8
(AT400/AT401) Errata Notice document. This is available from Arm on
request but it seems to be findable via a web search.

Differential Revision: https://reviews.llvm.org/D67284

llvm-svn: 371965

2019-09-16 09:38:38 +00:00

3 Commits