Commit Graph

26 Commits

Author SHA1 Message Date
Georgii Rymar e98d5c3192 [libObject,llvm-readelf/obj] - Don't use @@ when printing versions of undefined symbols.
A default version (@@) is only available for defined symbols.

Currently we use "@@" for undefined symbols too.
This patch fixes the issue and improves our test case.

Differential revision: https://reviews.llvm.org/D95219
2021-01-26 12:05:59 +03:00
Georgii Rymar 51f4958057 [yaml2obj/obj2yaml] - Improve dumping/creating of ELF versioning sections.
This makes the following improvements.

For `SHT_GNU_versym`:
 * yaml2obj: set `sh_link` to index of `.dynsym` section automatically.
For `SHT_GNU_verdef`:
 * yaml2obj: set `sh_link` to index of `.dynstr` section automatically.
 * yaml2obj: set `sh_info` field automatically.
 * obj2yaml: don't dump the `Info` field when its value matches the number of version definitions.
For `SHT_GNU_verneed`:
 * yaml2obj: set `sh_link` to index of `.dynstr` section automatically.
 * yaml2obj: set `sh_info` field automatically.
 * obj2yaml: don't dump the `Info` field when its value matches the number of version dependencies.

Also, simplifies few test cases.

Differential revision: https://reviews.llvm.org/D94956
2021-01-21 10:36:48 +03:00
Georgii Rymar 45ef053bd7 [llvm-readobj][test] - Remove excessive YAML fields from tests.
This removes excessive YAML keys from `SHT_GNU_verdef` sections.
Those keys are set by default.

Differential revision: https://reviews.llvm.org/D94660
2021-01-15 12:46:39 +03:00
Georgii Rymar 141906fa14 [llvm-readelf/obj] - Add support of multiple SHT_SYMTAB_SHNDX sections.
Currently we don't support multiple SHT_SYMTAB_SHNDX sections
and the DT_SYMTAB_SHNDX tag currently.

This patch implements it and fixes the
https://bugs.llvm.org/show_bug.cgi?id=43991.

I had to introduce the `struct DataRegion` to ELF.h,
it is used to represent a region that might have no known size.
It is needed, because we don't know the size of the extended
section indices table when it is located via DT_SYMTAB_SHNDX.
In this case we still want to validate that we don't read
past the end of the file.

Differential revision: https://reviews.llvm.org/D92923
2021-01-13 11:36:43 +03:00
Georgii Rymar 1daace3fbb [llvm-readelf/obj] - Lowercase the warning message reported.
Our warnings/errors reported are using lowercase normally.

This addresses one of review comments from D92382.
2020-12-02 13:09:47 +03:00
Georgii Rymar 21b6c04e3a [llvm-readelf/obj] - Report unique warnings in `parseDynamicTable`.
This makes the warnings reported to be unique and adds test cases.

Differential revision: https://reviews.llvm.org/D92382
2020-12-02 12:52:42 +03:00
Georgii Rymar 01e49204b8 [llvm-readelf/obj] - Refine the error message about the broken string table.
This:
1) Changes `reportWarning` to `reportUniqueWarning` (no-op here).
2) Adds more context to the message.
3) Merges `broken-dynsym-link.test` into `dyn-symbols.test`, adds more testing.

Differential revision: https://reviews.llvm.org/D92380
2020-12-02 12:06:16 +03:00
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 28b84dd138 [llvm-readobj/elf] - Stop reporting invalid extended indexes in warnings for unnamed section symbols.
We have an issue with `getFullSymbolName`: it assumes that the symbol passed is
always in the `.symtab`, what is wrong. We might calculate and report a wrong index currently.
I've added a test case revealing that.

This patch adds the "symbol index" argument to `getFullSymbolName` signature,
what fixes the issue.

Differential revision: https://reviews.llvm.org/D87899
2020-09-22 11:55:15 +03:00
Georgii Rymar 095f6fbbd7 [llvm-readelf/obj] - Stop printing invalid names for unnamed section symbols.
We have an issue with `ELFDumper<ELFT>::getSymbolSectionName`:
1) It is used deeply for both LLVM/GNU styles and might return LLVM-style only
   values to describe symbols: "Undefined", "Processor Specific", "Absolute", etc.

2) `getSymbolSectionName` is used by `getFullSymbolName` and these special values
   might appear instead of symbol names in many places.
   This occurs for unnamed section symbols currently.

This patch extracts the LLVM specific logic to `LLVMStyle<ELFT>::printSymbolSection`,
which seems to be the only place where we want to print the special values mentioned.
It also adds a meaningful new warning that is reported when we are unable to get
a section index for a section symbol.

Differential revision: https://reviews.llvm.org/D87764
2020-09-21 13:05:46 +03:00
Georgii Rymar 0dca1ac617 [llvm-readelf/obj][test] - Document what we print in various places for unnamed section symbols.
We have an issue with `ELFDumper<ELFT>::getSymbolSectionName`:
1) It is used deeply for both LLVM/GNU styles and might return LLVM-style only
   values to describe symbols: "Undefined", "Processor Specific", "Absolute", etc.

2) `getSymbolSectionName` is used by `getFullSymbolName` and these special values
   might appear in instead of symbol names in many places.
   This occurs for unnamed section symbols.

It was not noticed because for most cases I've found it is unexpected to have an
unnamed section symbol. This patch documents the existent behavior, adds tests and FIXMEs.

Differential revision: https://reviews.llvm.org/D87763
2020-09-17 15:56:51 +03:00
Georgii Rymar 275bed899e [llvm-readelf/obj] - Change the return type of the `createDRI(...)` to `Expected<>`
This allows to get rid of "Invalid data was encountered while parsing the file"
error reported in cases when sh_size/sh_offset of sections are broken.

Differential revision: https://reviews.llvm.org/D86451
2020-08-25 12:11:26 +03:00
Georgii Rymar a6436b0b3a [yaml2obj] - Make the 'Machine' key optional.
Currently we have to set 'Machine' to something in our
YAML descriptions. Usually we use 'EM_X86_64' for 64-bit targets
and 'EM_386' for 32-bit targets. At the same time, in fact, in most
cases our tests do not need a machine type and we can use
'EM_NONE'.

This is cleaner, because avoids the need of using a particular machine.

In this patch I've made the 'Machine' key optional (the default value,
when it is not specified is `EM_NONE`) and removed it (where possible)
from yaml2obj, obj2yaml and llvm-readobj tests.

There are few tests left where I decided not to remove it, because
I didn't want to touch CHECK lines or doing anything more complex
than a removing a "Machine: *" line and formatting lines around.

Differential revision: https://reviews.llvm.org/D86202
2020-08-20 11:40:51 +03:00
Georgii Rymar 2bca784ab8 [llvm-readobj] - Massive test cases cleanup.
This patch does the following:
1) Starts using YAML macro to reduce the number of YAML documents in tests.
2) Adds `#` before 'RUN'/`CHECK` lines in a few tests where it is missing.
3) Removes unused YAML keys.
4) Starts using `ENTSIZE=<none>` to simplify tests (see D84526).
5) Removes trailing white spaces in a few places.

Differential revision: https://reviews.llvm.org/D85013
2020-08-03 14:07:06 +03:00
Georgii Rymar e2529e2dfa [llvm-readobj] - Don't get the name of the symbol table in ELFDumper<ELFT>::printSymbolsHelper.
It was requested in D84173 thread to not do it, because otherwise we extract and
check the name of the symbol table in LLVM style, but do not use it and
might report a warning which perhaps might be confusing.

Differential revision: https://reviews.llvm.org/D84231
2020-07-22 17:28:20 +03:00
Georgii Rymar 3520297039 [llvm-readelf] - Introduce describe() helper functions.
These functions can be used to generate strings like
"SHT_?? section with index ?" to describe sections in error/warning messages,
what helps to simplify and generalize them.

Also this allows to isolate the following common code pattern:
`&Sec - &cantFail(Obj->sections()).front();`

Differential revision: https://reviews.llvm.org/D84240
2020-07-22 14:03:17 +03:00
Georgii Rymar 54ef74f738 [llvm-readobj/readelf] - Don't fail dumping when unable to read the name of the SHT_DYNSYM section.
We have an issue currently: we are trying to read the name of the SHT_DYNSYM section
very early and using `unwrapOrError` call for that.

The name is needed only for the GNU output. Because of the current logic, the tool
fails to dump the whole object when something is wrong with the name of the .dynsym section.

This patch delays reading the name and also allows it to be broken.

Differential revision: https://reviews.llvm.org/D84173
2020-07-22 13:11:46 +03:00
Georgii Rymar 64156347ba [llvm-readelf] - Do not error out when dumping symbols.
When the --symbols option/--dyn-symbols is given we might report an
error and exit when something goes not right. E.g. when the SHT_SYMTAB
section is broken. Though we could report a warning and try to continue
dumping instead in many cases.

This patch removes `unwrapOrErr` calls from the code involved in the
flow described.

Differential revision: https://reviews.llvm.org/D82955
2020-07-03 11:55:35 +03:00
Georgii Rymar f38f068b14 [llvm-readelf] - Do not crash when dumping the dynamic symbol table when its sh_entzize == 0.
We have a division by zero crash currently when
the sh_entzize of the dynamic symbol table is 0.

Differential revision: https://reviews.llvm.org/D82180
2020-06-22 15:41:34 +03:00
Georgii Rymar ba808b157e [llvm-readobj] - Validate the DT_STRSZ value to avoid crash.
It is possible to trigger a crash when a dynamic symbol has a
broken (too large) st_name and the DT_STRSZ is also broken.

We have the following code in the `Elf_Sym_Impl<ELFT>::getName`:

```
template <class ELFT>
Expected<StringRef> Elf_Sym_Impl<ELFT>::getName(StringRef StrTab) const {
  uint32_t Offset = this->st_name;
  if (Offset >= StrTab.size())
    return createStringError(object_error::parse_failed,
                             "st_name (0x%" PRIx32
                             ") is past the end of the string table"
                             " of size 0x%zx",
                             Offset, StrTab.size());
...
```

The problem is that `StrTab` here is a `ELFDumper::DynamicStringTab` member
which is not validated properly on initialization. So it is possible to bypass the
`if` even when the `st_name` is huge.

This patch fixes the issue.

Differential revision: https://reviews.llvm.org/D82201
2020-06-22 15:24:59 +03:00
Georgii Rymar b87a0f7416 [llvm-readobj] - Report a warning when an unexpected DT_SYMENT tag value is met.
There was a short discussion about this:
https://reviews.llvm.org/D73484#inline-676942

To summarize:
It is a bit unclear to me why the `DT_SYMENT` tag exist.
LLD has the code that does:
"addInt(DT_SYMENT, sizeof(Elf_Sym));" and I guess other linkers has the same logic.
It is unclear why it can be possible to have other values rather than values of
a size of platform symbol. Seems it is not possible, and atm for me it looks that
this tag should not be used. This patch starts reporting the warning when the
value it contains differs from a symbol size for a 32/64 bit platform for safety.
It keeps the rest of the logic we have unchanged. Before this patch we did not handle
the tag at all.

Differential review: https://reviews.llvm.org/D74479
2020-02-18 14:36:17 +03:00
Georgii Rymar 2930dab315 [llvm-readobj] - Improve error message reported by DynRegionInfo.
DynRegionInfo is a helper class used to create memory ranges.
It is used for many things and can report errors.
Errors reported currently do not provide a good diagnostic.
This patch fixes it and adds a test for each possible case.

Differential revision: https://reviews.llvm.org/D73484
2020-01-30 14:34:20 +03:00
Georgii Rymar 5c6f8f73ff [llvm-readobj] - Add a test for --dyn-symbols when there are no dynamic symbols.
It removes the Object/readobj-absent.test test and creates a one more case in
dyn-symbols.test we have.

Differential revision: https://reviews.llvm.org/D73169
2020-01-27 12:34:58 +03:00
Georgii Rymar 5f6ff71641 [llvm-readobj][test] - Add a check for --dyn-syms.
We have a `-dyn-symbols` option. It has a `--dyn-syms` alias
that is not tested in llvm-readobj tests currently.

There was a Object/readobj-elf-versioning.test where it is used,
but I've removed it in D73163. And also it is not the
right place to test it anyways.

Differential revision: https://reviews.llvm.org/D73164
2020-01-23 12:20:19 +03:00
Georgii Rymar 18188a7f44 [llvm-readobj][test] - Improve dyn-symbols.test.
This removes the precompiled binary used, simplifies
the first test case, adds comments and llvm-readelf tool
invocations.
It also adds a test case for checking versioning symbols.

Differential revision: https://reviews.llvm.org/D71595
2019-12-19 11:39:45 +03:00
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