In this patch `llvm-readobj` prints ASEs flags on a single line
separated by a comma. GNU `readelf` prints each ASEs flag on
a separate line. It will be fixed later.
llvm-svn: 373732
Initially llvm-readobj supports multiple command line options like
`--arm-attributes` and `--mips-plt-got` for display ELF arch-specific
information. Now all these options are superseded by the
`--arch-specific` one. It makes sense to have a single `printArchSpecificInfo`
method in the base `ObjDumper`, and hide all ELF/target specific details
in the `ELFDumper::printArchSpecificInfo` override.
Differential Revision: https://reviews.llvm.org/D68385
llvm-svn: 373731
llvm-readobj "non-standard" flags `--mips-plt-got`, `--mips-abi-flags`,
`--mips-reginfo`, and `--mips-options` are superseded by the `--arch-specific`
flag and can be removed now.
llvm-svn: 373590
It is possible to craft a .hash section that triggers an infinite loop
in llvm-readelf code. This patch fixes the issue and introduces
a warning.
Differential revision: https://reviews.llvm.org/D68086
llvm-svn: 373476
D68110 added --arch-specific (supported by GNU readelf) and made
--arm-attributes an alias for it. The tests were later migrated to use
--arch-specific.
Note, llvm-readelf --arch-specific currently just uses llvm-readobj
style output for ARM attributes. The readelf-style output is not
implemented.
Reviewed By: compnerd, kongyi, rupprecht
Differential Revision: https://reviews.llvm.org/D68196
llvm-svn: 373291
This is for compatibility with GNU readobj. --arm-attributes option is
left as a hidden alias due to large number of tests using it.
Differential Revision: https://reviews.llvm.org/D68110
llvm-svn: 373125
I started this patch as a refactoring, tried to make a helper for
getting symbol names, similar to how we get section names
used in warning messages.
So this patch cleanups the code and fixes an issue: symbol names
in warning messages were not demangled.
Differential revision: https://reviews.llvm.org/D68012
llvm-svn: 372867
The crash might happen when we have either a broken or unsupported object
and trying to resolve relocations when dumping the .stack_sizes section.
For the test case I used a 32-bits ELF header and a 64-bit relocation.
In this case a null pointer is returned by the code instead of the relocation
resolver function and then we crash.
Differential revision: https://reviews.llvm.org/D67962
llvm-svn: 372838
llvm-readobj currently handles .stack_sizes.* (e.g. .stack_sizes.foo)
as a normal stack sizes section. Though MC does not produce sections with
such names. Also, linkers do not combine .stack_sizes.* into .stack_sizes.
A mini discussion about this correctness issue is here: https://reviews.llvm.org/D67757#inline-609274
This patch changes implementation so that only now only '.stack_sizes' name is
accepted as a real stack sizes section.
Differential revision: https://reviews.llvm.org/D67824
llvm-svn: 372578
The new constructor can simplify some llvm-readobj call sites.
Reviewed By: grimar, dblaikie
Differential Revision: https://reviews.llvm.org/D67797
llvm-svn: 372473
Before this patch we gave a priority to a dynamic table found
from the section header.
It was discussed (here: https://reviews.llvm.org/D67078?id=218356#inline-602082)
that probably preferring the table from PT_DYNAMIC is better,
because it is what runtime loader sees.
This patch makes the table from PT_DYNAMIC be chosen at first place if it is available.
But also it adds logic to fall back to SHT_DYNAMIC if the table from the dynamic segment is
broken or fall back to use no table if both are broken.
It adds a few more diagnostic warnings for the logic above.
Differential revision: https://reviews.llvm.org/D67547
llvm-svn: 372122
It's a straightforward refactoring that allows to simplify and encapsulate the code.
Differential revision: https://reviews.llvm.org/D67624
llvm-svn: 372083
This is a fix for https://bugs.llvm.org/show_bug.cgi?id=40785.
llvm-readelf does not print the st_value of the symbol when
st_value has any non-visibility bits set.
This patch:
* Aligns "Ndx" row for the default and a new cases.
(it was 1 space character off for the case when "PROTECTED" visibility was printed)
* Prints "[<other>: 0x??]" for symbols which has an additional st_other bits set.
In compare with GNU, this logic is a bit simpler and seems to be more consistent.
For MIPS GNU can print named flags, though can't print a mix of them:
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 NOTYPE GLOBAL DEFAULT [OPTIONAL] UND a1
2: 00000000 0 NOTYPE GLOBAL DEFAULT [MIPS PLT] UND a2
3: 00000000 0 NOTYPE GLOBAL DEFAULT [MIPS PIC] UND a3
4: 00000000 0 NOTYPE GLOBAL DEFAULT [MICROMIPS] UND a4
5: 00000000 0 NOTYPE GLOBAL DEFAULT [MIPS16] UND a5
6: 00000000 0 NOTYPE GLOBAL DEFAULT [<other>: c] UND b1
7: 00000000 0 NOTYPE GLOBAL DEFAULT [<other>: 28] UND b2
On PPC64 it can print a localentry value that is encoded in the high bits of st_other
63: 0000000000000850 208 FUNC GLOBAL DEFAULT [<localentry>: 8] 12
We chose to print the raw st_other field, prefixed with '0x'.
Differential revision: https://reviews.llvm.org/D67094
llvm-svn: 371201
See http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html
and D60242 for the lld partition feature.
This patch:
* Teaches yaml2obj to parse the 3 section types.
* Teaches llvm-readobj/llvm-readelf to dump the 3 section types.
There is no test for SHT_LLVM_DEPENDENT_LIBRARIES in llvm-readobj. Add
it as well.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D67228
llvm-svn: 371157
D62179 introduced a regression. llvm-readelf lose the ability to dump the dynamic symbols
when there is .dynamic section with a DT_SYMTAB, but there are no program headers:
https://reviews.llvm.org/D62179#1652778
Below is a program flow before the D62179 change:
1) Find SHT_DYNSYM.
2) Find there is no PT_DYNAMIC => don't try to parse it.
3) Print dynamic symbols using information about them found on step (1).
And after the change it became:
1) Find SHT_DYNSYM.
2) Find there is no PT_DYNAMIC => find SHT_DYNAMIC.
3) Parse dynamic table, but fail to handle the DT_SYMTAB because of the absence of the PT_LOAD. Report the "Virtual address is not in any segment" error.
This patch fixes the issue. For doing this it checks that the value of DT_SYMTAB was
mapped to a segment. If not - it ignores it.
Differential revision: https://reviews.llvm.org/D67078
llvm-svn: 371071
This allows llvm-readobj to print the contents of each resource
when printing resources from an object file or executable, like it
already does for plain .res files.
This requires providing the whole COFFObjectFile to ResourceSectionRef.
This supports both object files and executables. For executables,
the DataRVA field is used as is to look up the right section.
For object files, ideally we would need to complete linking of them
and fix up all relocations to know what the DataRVA field would end up
being. In practice, the only thing that makes sense for an RVA field
is an ADDR32NB relocation. Thus, find a relocation pointing at this
field, verify that it has the expected type, locate the symbol it
points at, look up the section the symbol points at, and read from the
right offset in that section.
This works both for GNU windres object files (which use one single
.rsrc section, with all relocations against the base of the .rsrc
section, with the original value of the DataRVA field being the
offset of the data from the beginning of the .rsrc section) and
cvtres object files (with two separate .rsrc$01 and .rsrc$02 sections,
and one symbol per data entry, with the original pre-relocated DataRVA
field being set to zero).
Differential Revision: https://reviews.llvm.org/D66820
llvm-svn: 370433
Add an WASM_SYMBOL_NO_STRIP flag, so that __attribute__((used)) doesn't
need to imply exporting. When targeting Emscripten, have
WASM_SYMBOL_NO_STRIP imply exporting.
Differential Revision: https://reviews.llvm.org/D62542
llvm-svn: 370415
When we have a dynamic relocation with a broken symbol's st_name,
tools report a useless error: "Invalid data was encountered while parsing the file".
After this change we report a warning + "<corrupt>" as a symbol name.
Differential revision: https://reviews.llvm.org/D66734
llvm-svn: 370330
Instead of blindly incrementing pointers in llvm-readobj, use this
helper, which does bounds checking against the available section
data.
Differential Revision: https://reviews.llvm.org/D66818
llvm-svn: 370310
Summary:
This patch implements main entry and auxiliary entries of symbol table generation for llvm-readobj on AIX.
The source code of aix_xcoff_xlc_test8.o (compile with xlc) is:
-bash-4.2$ cat test8.c
extern int i;
extern int TestforXcoff;
extern int fun(int i);
static int static_i;
char* p="abcd";
int fun1(int j) {
static_i++;
j++;
j=j+*p;
return j;
}
int main() {
i++;
fun(i);
return fun1(i);
}
Patch provided by DiggerLin
Differential Revision: https://reviews.llvm.org/D65240
llvm-svn: 370097
We do not need it, std::error_code is used mostly for COFF and
this patch rewrites the calls to use a different overload.
Having reportError(std::error_code EC, ... is excessive by itself,
because API that use error codes actually needs refactoring to
use Error/Expected<> instead.
DIfferential revision: https://reviews.llvm.org/D66521
llvm-svn: 369630
Summary:
Currently, we report:
error: ...
Prepend argv[0] (tool name):
llvm-readobj: error: ...
This is consistent with most GNU binutils/clang/lld, and gives a bit
more context in a long build log.
Reviewed By: grimar, jhenderson, rupprecht
Differential Revision: https://reviews.llvm.org/D66425
llvm-svn: 369377
There are 4 methods that return std::error_code now,
though they do not have to because they are always succeed.
I refactored them.
This allows to simplify the code in tools a bit.
llvm-svn: 369263
Fix: Add a `consumeError` call removed by mistake to 'printStackSize',
this should fix the "Expected<T> must be checked before access or destruction." reported by following bot:
http://lab.llvm.org:8011/builders/clang-x64-windows-msvc/builds/9743/steps/stage%201%20check/logs/stdio
Original commit message:
Currently we have the following functions for error reporting:
LLVM_ATTRIBUTE_NORETURN void reportError(Twine Msg);
void reportError(Error Err, StringRef Input);
void reportWarning(Twine Msg);
void reportWarning(StringRef Input, Error Err);
void warn(llvm::Error Err);
void error(std::error_code EC);
Problems are: naming is inconsistent, arguments order is inconsistent,
some of the functions looks excessive.
After applying this patch we have:
void reportError(Error Err, StringRef Input);
void reportError(std::error_code EC, StringRef Input);
void reportWarning(Error Err, StringRef Input);
I'd be happy to remove reportError(std::error_code EC, StringRef Input) too, but it
is used by COFF heavily.
Test cases were updated, they show an improvement introduced.
Differential revision: https://reviews.llvm.org/D66286
llvm-svn: 369194
Few BB failed with the following error:
Command Output (stderr):
--
/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/test/tools/llvm-readobj/stack-sizes.test:263:19: error: BADSECTION-OUT: expected string not found in input
# BADSECTION-OUT: 8 ?
^
<stdin>:4:1: note: scanning from here
^
It doesn't reproduce on ubuntu/windows I have. Also, seems many of the bots
are happy too.
This slightly reorders the code to make fouts().flush() call earlier,
like it was before the r369191.
llvm-svn: 369192
urrently we have the following functions for error reporting:
--
LLVM_ATTRIBUTE_NORETURN void reportError(Twine Msg);
void reportError(Error Err, StringRef Input);
void reportWarning(Twine Msg);
void reportWarning(StringRef Input, Error Err);
void warn(llvm::Error Err);
void error(std::error_code EC);
---
Problems are: naming is inconsistent, arguments order is inconsistent,
some of the functions looks excessive.
After applying this patch we have:
---
LLVM_ATTRIBUTE_NORETURN void reportError(Error Err, StringRef Input);
LLVM_ATTRIBUTE_NORETURN void reportError(std::error_code EC, StringRef Input);
void reportWarning(Error Err, StringRef Input);
---
I'd be happy to remove reportError(std::error_code EC, StringRef Input) too, but it
is used by COFF heavily.
Test cases were updated, they show an improvement introduced.
Differential revision: https://reviews.llvm.org/D66286
llvm-svn: 369190
This addresses the issue introduced in r369169, we need to unwrap
the value first before we can check whether it's empty. This also
swaps the two branches to put the common path first which should
be NFC.
llvm-svn: 369177
This is useful when trying to read notes from stripped files and matches
the behavior of GNU readelf and eu-readelf.
Differential Revision: https://reviews.llvm.org/D66358
llvm-svn: 369169
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
Changes: no changes. A fix for the clang code will be landed right on top.
Original commit message:
SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.
For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)
This patch makes a change for all users to switch to Expected<> version.
Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).
Differential revision: https://reviews.llvm.org/D66089
llvm-svn: 368826
SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.
For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)
This patch makes a change for all users to switch to Expected<> version.
Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).
Differential revision: https://reviews.llvm.org/D66089
llvm-svn: 368812
I am changing this to work around an issue that is being hit when
building with clang 3.8. Specifically, clang 3.8 requires that we have a user
defined default constructor for SectionRef for the default initialization of a
const SectionRef.
llvm-svn: 368758
Summary:
This patch implements two note parsers; one for NT_FILE coredumps, e.g.:
```
CORE 0x00000080 NT_FILE (mapped files)
Page size: 4096
Start End Page Offset
0x0000000000001000 0x0000000000002000 0x0000000000003000
/path/to/a.out
0x0000000000004000 0x0000000000005000 0x0000000000006000
/path/to/libc.so
0x0000000000007000 0x0000000000008000 0x0000000000009000
[stack]
```
(A more realistic example can be tested locally by creating a crashing program and running `llvm-readelf -n core`)
And also implements a raw hex dump for unknown descriptor data for unhandled descriptor types.
Reviewers: MaskRay, jhenderson, grimar, alexshap
Reviewed By: MaskRay, grimar
Subscribers: emaste, llvm-commits, labath
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65832
llvm-svn: 368698
This patch addresses two closely related bugs:
https://bugs.llvm.org/show_bug.cgi?id=42930 and
https://bugs.llvm.org/show_bug.cgi?id=42931.
GNU readelf prints the file name for every input unless there is only
one input and that input is not an archive. This patch adds the printing
for multiple inputs. A previous change did it for archives, but
introduced a regression with GNU compatibility for single-output
formatting, resulting in a spurious initial blank line. This is fixed in
this patch too.
Reviewed by: grimar, MaskRay
Differential Revision: https://reviews.llvm.org/D65953
llvm-svn: 368435
This is a bit strange method. It works like a unwrapOrError,
but named error. It does not report an Input name.
I removed it.
Differential revision: https://reviews.llvm.org/D66000
llvm-svn: 368430
This patch changes the code to use a modern unwrapOrError(StringRef Input, Expected<T> EO)
version that contains the input source name and removes the deprecated version.
Differential revision: https://reviews.llvm.org/D65946
llvm-svn: 368428
It is outdated. Using of Expected<> is preferred, also it does
not provide a way to report a file name.
I updated the code to use the modern version of unwrapOrError instead.
Differential revision: https://reviews.llvm.org/D65951
llvm-svn: 368410
Currently, we have a code duplication in llvm-readobj which was introduced in D63266.
The duplication was introduced to allow llvm-readobj to dump the partially
broken object. Methods in ELFFile<ELFT> perform a strict validation of the inputs,
what is itself good, but not for dumper tools, that might want to dump the information,
even if some pieces are broken/unexpected.
This patch introduces a warning handler which can be passed to ELFFile<ELFT> methods
and can allow skipping the non-critical errors when needed/possible.
For demonstration, I removed the duplication from llvm-readobj and implemented a warning using
the new custom warning handler. It also deduplicates the strings printed, making the output less verbose.
Differential revision: https://reviews.llvm.org/D65515
llvm-svn: 368260
readelf -n:
```
// "Data size" is not left justified
Owner Data size Description
GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)
```
llvm-readelf -n (before):
```
// "Data size" column shifted by 1
Owner Data size Description
GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)
```
llvm-readelf -n (after):
```
Owner Data size Description
GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)
```
This change is made to reduce the diff with readelf -n, so that it is
slightly easier to check what features readelf implements but we don't.
Reviewed By: grimar, jhenderson
Differential Revision: https://reviews.llvm.org/D65847
llvm-svn: 368138
This updates all libraries and tools in LLVM Core to use 64-bit offsets
which directly or indirectly come to DataExtractor.
Differential Revision: https://reviews.llvm.org/D65638
llvm-svn: 368014
When e_shstrndx is broken, it is impossible to get a section name.
In this patch I improved the error message we show and
added tests for Object and for llvm-readelf/llvm-readobj
Message was changed in two places:
1) llvm-readelf/llvm-readobj previously used a code from Object/ELF.h,
now they have a modified version of it (it has less checks and allows
dumping broken things).
2) Code in Object/ELF.h is still used for generic cases.
Differential revision: https://reviews.llvm.org/D64714
llvm-svn: 366203
It does not make sence to stop dumping the object if the broken
dynamic section was found. In this patch I changed the behavior from
"report an error" to "report a warning". This matches GNU.
Differential revision: https://reviews.llvm.org/D64472
llvm-svn: 365762
Adds a readobj dumper for 32-bit and 64-bit section header tables, and extend
support for the file-header dumping to include 64-bit object files. Also
refactors the binary file parsing to be done in a helper function in an attempt
to cleanup error handeling.
Differential Revision: https://reviews.llvm.org/D63843
llvm-svn: 365524
Many LLVM-based tools already support response files (i.e. files
containing a list of options, specified with '@'). This change simply
updates the documentation and help text for some of these tools to
include it. I haven't attempted to fix all tools, just a selection that
I am interested in.
I've taken the opportunity to add some tests for --help behaviour, where
they were missing. We could expand these tests, but I don't think that's
within scope of this patch.
This fixes https://bugs.llvm.org/show_bug.cgi?id=42233 and
https://bugs.llvm.org/show_bug.cgi?id=42236.
Reviewed by: grimar, MaskRay, jkorous
Differential Revision: https://reviews.llvm.org/D63597
llvm-svn: 364036
Some versions of the Visual C++ 2015 runtime have line tables with the
subsection kind of 0x800000F2. In cvinfo.h, 0x80000000 is documented to
be DEBUG_S_IGNORE. This appears to implement the intended behavior.
llvm-svn: 363724
1) `-x foo` currently dumps one `foo`. This change makes it dump all `foo`.
2) `-x foo -x foo` currently dumps `foo` twice. This change makes it dump `foo` once.
In addition, if foo has section index 9, `-x foo -x 9` dumps `foo` once.
3) Give a warning instead of an error if `foo` does not exist.
The new behaviors match GNU readelf.
Also, print a new line as a separator between two section dumps.
GNU readelf uses two lines, but one seems good enough.
Reviewed By: grimar, jhenderson
Differential Revision: https://reviews.llvm.org/D63475
llvm-svn: 363683
If dynamic table is missing, output "dynamic strtab not found'. If the index is
out of range, output "Invalid Offset<..>".
https://bugs.llvm.org/show_bug.cgi?id=40807
Reviewed by: jhenderson, grimar, MaskRay
Differential Revision: https://reviews.llvm.org/D63084
Patch by Yuanfang Chen.
llvm-svn: 363374
Summary:
Use llvm::fouts() as the default stream for outputing. No new stream
should be constructed to output at the same time.
https://bugs.llvm.org/show_bug.cgi?id=42140
Reviewers: jhenderson, grimar, MaskRay, phosek, rupprecht
Reviewed By: rupprecht
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63115
Patch by Yuanfang Chen!
llvm-svn: 363198
ELF for the 64-bit Arm Architecture defines two processor-specific dynamic
tags:
DT_AARCH64_BTI_PLT 0x70000001, d_val
DT_AARCH64_PAC_PLT 0x70000003, d_val
These presence of these tags indicate that PLT sequences have been
protected using Branch Target Identification and Pointer Authentication
respectively. The presence of both indicates that the PLT sequences have
been protected with both Branch Target Identification and Pointer
Authentication.
This patch adds the tags and tests for llvm-readobj and yaml2obj.
As some of the processor specific dynamic tags overlap, this patch splits
them up, keeping their original default value if they were not previously
mentioned explicitly in a switch case.
Differential Revision: https://reviews.llvm.org/D62596
llvm-svn: 362493
ELF for the 64-bit Arm Architecture defines a processor specific property
type GNU_PROPERTY_AARCH64_FEATURE_1_AND as GNU_PROPERTY_LOPROC. This
property works in a similar way to the existing X86 processor specific
property GNU_PROPERTY_GNU_X86_FEATURE_1_AND.
Two feature bits are defined for GNU_PROPERTY_AARCH64_FEATURE_1_AND:
- GNU_PROPERTY_AARCH64_FEATURE_1_BTI 0x1
- GNU_PROPERTY_AARCH64_FEATURE_1_PAC 0x2
This patch defines the property, feature bits and implements support for
printing in llvm-readobj.
Differential Revision: https://reviews.llvm.org/D62595
llvm-svn: 362490
BB failed:
http://lab.llvm.org:8011/builders/clang-armv7-linux-build-cache/builds/15062/steps/build%20stage%201/logs/stdio
Error was:
/home/buildslave/buildslave/clang-armv7-linux-build-cache/llvm/tools/llvm-readobj/ELFDumper.cpp:3540:7:
error: non-constant-expression cannot be narrowed from type 'llvm::support::detail::packed_endian_specific_integral<unsigned long long,
llvm::support::endianness::little, 1>::value_type' (aka 'unsigned long long') to 'size_t' (aka 'unsigned int') in initializer list [-Wc++11-narrowing]
StrTabSec->sh_size};
llvm-svn: 362084
It is now possible after D61937 was landed and was discussed
in it's review comments. It is not consistent with GNU, which
does not output .dynamic section content in this case for
no visible reason.
Differential revision: https://reviews.llvm.org/D62179
llvm-svn: 361943
This is how multi-partition combined output files are going to look. If we
see multiple sections, the tools will just read the first one.
Differential Revision: https://reviews.llvm.org/D62349
llvm-svn: 361869
Summary:
This patch implement parsing symbol table for xcoffobjfile and
output as yaml format. Parsing auxiliary entries of a symbol
will be in a separate patch.
The XCOFF object file (aix_xcoff.o) used in the test comes from
-bash-4.2$ cat test.c
extern int i;
extern int TestforXcoff;
int main()
{
i++;
TestforXcoff--;
}
Patch by DiggerLin
Reviewers: sfertile, hubert.reinterpretcast, MaskRay, daltenty
Differential Revision: https://reviews.llvm.org/D61532
llvm-svn: 361832
They were failing on 32-bit Windows. In the cases where I've changed
test expectations, I've checked that they match the output of GNU
readelf.
llvm-svn: 361807
GNU readelf tool prints slightly different dynamic table "header" and
surrounds dynamic tag names by brackets. This patch implements the same
formatting for GNU-style output of the `llvm-readobj`.
LLVM
```
DynamicSection [ (13 entries)
Tag Type Name/Value
0x00000006 SYMTAB 0x168
...
]
```
GNU
```
Dynamic section at offset 0x1d0 contains 13 entries:
Tag Type Name/Value
0x00000006 (SYMTAB) 0x168
...
```
Differential Revision: https://reviews.llvm.org/D62256
llvm-svn: 361633
It is now possible after D61937 was landed and was discussed
in it's review comments. It is not consistent with GNU, which
does not output .dynamic section content in this case for
no visible reason.
Differential revision: https://reviews.llvm.org/D62179
llvm-svn: 361630
This is a result of what I found during my work on https://bugs.llvm.org/show_bug.cgi?id=41679.
Previously LLVM readelf took the information about .dynamic section
from its PT_DYNAMIC segment only. GNU tools have a bit different logic.
They also use the information from the .dynamic section header if it is available.
This patch changes the code to improve the compatibility with the GNU Binutils.
Differential revision: https://reviews.llvm.org/D61937
llvm-svn: 361165
This patch implements a limited form of autolinking primarily designed to allow
either the --dependent-library compiler option, or "comment lib" pragmas (
https://docs.microsoft.com/en-us/cpp/preprocessor/comment-c-cpp?view=vs-2017) in
C/C++ e.g. #pragma comment(lib, "foo"), to cause an ELF linker to automatically
add the specified library to the link when processing the input file generated
by the compiler.
Currently this extension is unique to LLVM and LLD. However, care has been taken
to design this feature so that it could be supported by other ELF linkers.
The design goals were to provide:
- A simple linking model for developers to reason about.
- The ability to to override autolinking from the linker command line.
- Source code compatibility, where possible, with "comment lib" pragmas in other
environments (MSVC in particular).
Dependent library support is implemented differently for ELF platforms than on
the other platforms. Primarily this difference is that on ELF we pass the
dependent library specifiers directly to the linker without manipulating them.
This is in contrast to other platforms where they are mapped to a specific
linker option by the compiler. This difference is a result of the greater
variety of ELF linkers and the fact that ELF linkers tend to handle libraries in
a more complicated fashion than on other platforms. This forces us to defer
handling the specifiers to the linker.
In order to achieve a level of source code compatibility with other platforms
we have restricted this feature to work with libraries that meet the following
"reasonable" requirements:
1. There are no competing defined symbols in a given set of libraries, or
if they exist, the program owner doesn't care which is linked to their
program.
2. There may be circular dependencies between libraries.
The binary representation is a mergeable string section (SHF_MERGE,
SHF_STRINGS), called .deplibs, with custom type SHT_LLVM_DEPENDENT_LIBRARIES
(0x6fff4c04). The compiler forms this section by concatenating the arguments of
the "comment lib" pragmas and --dependent-library options in the order they are
encountered. Partial (-r, -Ur) links are handled by concatenating .deplibs
sections with the normal mergeable string section rules. As an example, #pragma
comment(lib, "foo") would result in:
.section ".deplibs","MS",@llvm_dependent_libraries,1
.asciz "foo"
For LTO, equivalent information to the contents of a the .deplibs section can be
retrieved by the LLD for bitcode input files.
LLD processes the dependent library specifiers in the following way:
1. Dependent libraries which are found from the specifiers in .deplibs sections
of relocatable object files are added when the linker decides to include that
file (which could itself be in a library) in the link. Dependent libraries
behave as if they were appended to the command line after all other options. As
a consequence the set of dependent libraries are searched last to resolve
symbols.
2. It is an error if a file cannot be found for a given specifier.
3. Any command line options in effect at the end of the command line parsing apply
to the dependent libraries, e.g. --whole-archive.
4. The linker tries to add a library or relocatable object file from each of the
strings in a .deplibs section by; first, handling the string as if it was
specified on the command line; second, by looking for the string in each of the
library search paths in turn; third, by looking for a lib<string>.a or
lib<string>.so (depending on the current mode of the linker) in each of the
library search paths.
5. A new command line option --no-dependent-libraries tells LLD to ignore the
dependent libraries.
Rationale for the above points:
1. Adding the dependent libraries last makes the process simple to understand
from a developers perspective. All linkers are able to implement this scheme.
2. Error-ing for libraries that are not found seems like better behavior than
failing the link during symbol resolution.
3. It seems useful for the user to be able to apply command line options which
will affect all of the dependent libraries. There is a potential problem of
surprise for developers, who might not realize that these options would apply
to these "invisible" input files; however, despite the potential for surprise,
this is easy for developers to reason about and gives developers the control
that they may require.
4. This algorithm takes into account all of the different ways that ELF linkers
find input files. The different search methods are tried by the linker in most
obvious to least obvious order.
5. I considered adding finer grained control over which dependent libraries were
ignored (e.g. MSVC has /nodefaultlib:<library>); however, I concluded that this
is not necessary: if finer control is required developers can fall back to using
the command line directly.
RFC thread: http://lists.llvm.org/pipermail/llvm-dev/2019-March/131004.html.
Differential Revision: https://reviews.llvm.org/D60274
llvm-svn: 360984
r360876 didn't fix 2 call sites in clang.
Expected<ArrayRef<uint8_t>> may be better but use Expected<StringRef> for now.
Follow-up of D61781.
llvm-svn: 360892
It broke the Clang build, see llvm-commits thread.
> Expected<ArrayRef<uint8_t>> may be better but use Expected<StringRef> for now.
>
> Follow-up of D61781.
llvm-svn: 360878
In the r360676 "Apply clang format. NFC" I applied clang-format
for whole ELFDumper.cpp. It caused a little discussion,
one of the points mentioned was that previously nicely lined up
tables are not so nice now.
This patch reverts them.
llvm-svn: 360860
Patch adds support for dumping of file headers with llvm-readobj. XCOFF
object files are added to test dumping a well formed file, and dumping
both negative timestamps and negative symbol counts, both of which are
allowed in the XCOFF definition.
Differential Revision: https://reviews.llvm.org/D60878
llvm-svn: 359878
Summary:
It currently receives an output parameter and returns
std::error_code. Expected<StringRef> fits for this purpose perfectly.
Differential Revision: https://reviews.llvm.org/D61421
llvm-svn: 359774
Simon Atanasyan