Commit Graph

6 Commits

Author SHA1 Message Date
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 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
George Rimar 0e7ed91264 [yaml2obj][obj2yaml] - Add support for dumping/parsing .dynamic sections.
This teaches the tools to parse and dump
the .dynamic section and its dynamic tags.

Differential revision: https://reviews.llvm.org/D57691

llvm-svn: 353606
2019-02-09 11:34:28 +00:00
Armando Montanez 8367b0750f [elfabi] Add support for reading dynamic symbols from binaries
This patch adds initial support for reading dynamic symbols from ELF binaries. Currently, STT_NOTYPE, STT_OBJECT, STT_FUNC, and STT_TLS are explicitly supported. Other symbol types are mapped to ELFSymbolType::Unknown to improve signal/noise ratio.

Symbols must meet two criteria to be read into in an ELFStub:

 - The symbol's binding must be STB_GLOBAL or STB_WEAK.
 - The symbol's visibility must be STV_DEFAULT or STV_PROTECTED.

This filters out symbols that aren't of interest during compile-time linking against a shared object.

This change uses DT_HASH and DT_GNU_HASH to determine the size of .dynsym. Using hash tables to determine the number of symbols in .dynsym allows llvm-elfabi to work on binaries without relying on section headers.

Differential Revision: https://reviews.llvm.org/D56031

llvm-svn: 352121
2019-01-24 22:39:21 +00:00
Armando Montanez fe7ab3c22e [elfabi] Add support for reading DT_SONAME from binaries
This change gives the llvm-elfabi tool the ability to read DT_SONAME from a binary ELF file into an ELFStub.

Added:

 - DynamicEntries struct for storing dynamic entries that are relevant to elfabi.
 - terminatedSubstr() retrieves a null-terminated substring from a StringRef.
 - appendToError() appends a string to an error, allowing more specific error messages.

Differential Revision: https://reviews.llvm.org/D55629

llvm-svn: 351361
2019-01-16 17:47:16 +00:00