Commit Graph

11 Commits

Author SHA1 Message Date
Fangrui Song aa3df8ddcd [test] Avoid llvm-readelf/llvm-readobj one-dash long options and deprecated aliases (e.g. --file-headers) 2021-07-15 10:26:21 -07:00
Fangrui Song 46580d43fc [llvm-readobj] Switch command line parsing from llvm::cl to OptTable
Users should generally observe no difference as long as they don't use
unintended option forms. Behavior changes:

* `-t=d` is removed. Use `-t d` instead.
* `--demangle=false` and `--demangle=0` cannot be used. Omit the option or use `--no-demangle`. Other flag-style options don't have `--no-` forms.
* `--help-list` is removed. This is a `cl::` specific option.
* llvm-readobj now supports grouped short options as well.
* `--color` is removed. This is generally not useful (only apply to errors/warnings) but was inherited from Support.

Some adjustment to the canonical forms
(usually from GNU readelf; currently llvm-readobj has too many redundant aliases):

* --dyn-syms is canonical. --dyn-symbols is a hidden alias
* --file-header is canonical. --file-headers is a hidden alias
* --histogram is canonical. --elf-hash-histogram is a hidden alias
* --relocs is canonical. --relocations is a hidden alias
* --section-groups is canonical. --elf-section-groups is a hidden alias

OptTable avoids global option collision if we decide to support multiplexing for binary utilities.

* Most one-dash long options are still supported. `-dt, -sd, -st, -sr` are dropped due to their conflict with grouped short options.
* `--section-mapping=false` (D57365) is strange but is kept for now.
* Many `cl::opt` variables were unnecessarily external. I added `static` whenever appropriate.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D105532
2021-07-12 10:14:42 -07:00
Fangrui Song ca3bdb57fa [MC][ELF] Change SHT_LLVM_CALL_GRAPH_PROFILE relocations from SHT_RELA to SHT_REL
... even on targets preferring RELA. The section is only consumed by ld.lld
which can handle REL.

Follow-up to D104080 as I explained in the review. There are two advantages:

* The D104080 code only handles RELA, so arm/i386/mips32 etc may warn for -fprofile-use=/-fprofile-sample-use= usage.
* Decrease object file size for RELA targets

While here, change the relocation to relocate weights, instead of 0,1,2,3,..
I failed to catch the issue during review.
2021-06-24 21:35:48 -07:00
Alexander Yermolovich a224c5199b [LLD][LLVM] CG Graph profile using relocations
Currently when .llvm.call-graph-profile is created by llvm it explicitly encodes the symbol indices. This section is basically a black box for post processing tools. For example, if we run strip -s on the object files the symbol table changes, but indices in that section do not. In non-visible behavior indices point to wrong symbols. The visible behavior indices point outside of Symbol table: "invalid symbol index".

This patch changes the format by using R_*_NONE relocations to indicate the from/to symbols. The Frequency (Weight) will still be in the .llvm.call-graph-profile, but symbol information will be in relocation section. In LLD information from both sections is used to reconstruct call graph profile. Relocations themselves will never be applied.

With this approach post processing tools that handle relocations correctly work for this section also. Tools can add/remove symbols and as long as they handle relocation sections with this approach information stays correct.

Doing a quick experiment with clang-13.
The size went up from 107KB to 322KB, aggregate of all the input sections. Size of clang-13 binary is ~118MB. For users of -fprofile-use/-fprofile-sample-use the size of object files will go up slightly, it will not impact final binary size.

Reviewed By: jhenderson, MaskRay

Differential Revision: https://reviews.llvm.org/D104080
2021-06-24 09:09:33 -07:00
Georgii Rymar a7a447be0f [yaml2obj] - ProgramHeaders: introduce FirstSec/LastSec instead of Sections list.
Imagine we have a YAML declaration of few sections: `foo1`, `<unnamed 2>`, `foo3`, `foo4`.

To put them into segment we can do (1*):

```
Sections:
 - Section: foo1
 - Section: foo4
```

or we can use (2*):

```
Sections:
 - Section: foo1
 - Section: foo3
 - Section: foo4
```

or (3*) :

```
Sections:
 - Section: foo1
## "(index 2)" here is a name that we automatically created for a unnamed section.
 - Section: (index 2)
 - Section: foo3
 - Section: foo4
```

It looks really confusing that we don't have to list all of sections.

At first I've tried to make this rule stricter and report an error when there is a gap
(i.e. when a section is included into segment, but not listed explicitly).
This did not work perfect, because such approach conflicts with unnamed sections/fills (see (3*)).

This patch drops "Sections" key and introduces 2 keys instead: `FirstSec` and `LastSec`.
Both are optional.

Differential revision: https://reviews.llvm.org/D90458
2020-11-09 13:00:50 +03:00
Georgii Rymar 55a60af237 [llvm-readelf] - Implement --addrsig option.
We have `--addrsig` implemented for `llvm-readobj`.
Usually it is convenient to use a single tool for dumping,
so it seems we might want to implement `--addrsig` for `llvm-readelf` too.

I've selected a simple output format which is a bit similar to one,
used for dumping of the symbol table. It looks like:

```
Address-significant symbols section '.llvm_addrsig' contains 2 entries:
   Num: Name
     1: foo
     2: bar
```

Differential revision: https://reviews.llvm.org/D88835
2020-10-07 16:45:30 +03:00
Zequan Wu bbf89644b5 [llvm-readobj] set --elf-cg-profile as alias of --cg-profile
Summary: Rename --elf-cg-profile to --cg-profile and keep --elf-cg-profile as an alias of --cg-profile.

Reviewers: jhenderson, MaskRay, espindola, hans

Reviewed By: jhenderson, MaskRay

Subscribers: emaste, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81855
2020-06-17 11:24:45 -07:00
Georgii Rymar 3471ae9dad [yaml2obj] - Verify that sections are sorted by their file offsets when creating segments.
This validates that sections listed for a segment in the YAML
declaration are ordered by their file offsets.

It might help to simplify the file size computation, but also
is useful by itself as helps to avoid issues in test cases and
to maintain their readability.

Differential revision: https://reviews.llvm.org/D78361
2020-04-21 15:50:42 +03:00
Georgii Rymar b236b4cb43 [yaml2obj] - Set a default value for `PAddr` property of a program header to a value of `VAddr`
`PAddr` corresponds to `p_paddr` of a program header, which is the segment's physical
address for systems in which physical addressing is relevant. `p_paddr` is often equal
to `p_vaddr`, which is the virtual address of a segment.

This patch changes the default for `PAddr` from 0 to a value of `VAddr`.

Differential revision: https://reviews.llvm.org/D76131
2020-03-14 17:44:57 +03:00
Fangrui Song 55c81d4282 [test] Use yaml2obj -o %t instead of > %t
To improve consistency and avoid unneeded shell feature (output
redirection).

While here, make other changes to improve consistency

--docnum 1 => --docnum=1
-docnum=x => --docnum=x
2020-01-21 17:20:18 -08:00
Georgii Rymar dbf520f617 [llvm-readobj][test] - Move platform specific test cases and their inputs to separate folders.
This creates the next subfolders in the test directory:
"COFF", "ELF", "MachO", "wasm".

I've also removed platform specific prefixes, like "coff-*".
One unused binary was removed as well: `Inputs/relocs.obj.elf-mips`

Differential revision: https://reviews.llvm.org/D71203
2019-12-10 11:36:23 +03:00