Commit Graph

1444 Commits

Author SHA1 Message Date
Yi Kong b9d87b9528 [llvm-objdump] Add the missing ARMv8 subarch detection
Differential Revision: https://reviews.llvm.org/D66849

llvm-svn: 370163
2019-08-28 06:37:22 +00:00
Jason Liu 7c72e82b25 [XCOFF][AIX] Generate symbol table entries with llvm-readobj
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
2019-08-27 18:54:46 +00:00
Cyndy Ishida 9443d0e2c0 [Object] FIX: update PlatformKind name in TapiFile
Buildbots that use GCC failed to compile because overwritten
namespace with variable name

llvm-svn: 369602
2019-08-21 23:57:57 +00:00
Cyndy Ishida c20d1f90b5 [Object] Add tapi files to object
Summary:
The intention for this is to allow reading and printing symbols out from
llvm-nm. Tapi file, and Tapi universal follow a similiar format to
their respective MachO Object format.

The tests are dependent on llvm-nm processing tbd files which is why its in D66160

Reviewers: ributzka, steven_wu, lhames

Reviewed By: ributzka, lhames

Subscribers: mgorny, hiraditya, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66159

llvm-svn: 369600
2019-08-21 23:30:53 +00:00
Cyndy Ishida 359840a6e4 [BinaryFormat] Teach identify_magic about Tapi files.
Summary:
Tapi files are YAML files that start with the !tapi tag. The only execption are
TBD v1 files, which don't have a tag. In that case we have to scan a little
further and check if the first key "archs" exists.

This is the first patch in a series of patches to add libObject support for
text-based dynamic library (.tbd) files.

This patch is practically exactly the same as D37820, that was never pushed to master,
and is needed for future commits related to reading tbd files for llvm-nm

Reviewers: ributzka, steven_wu, bollu, espindola, jfb, shafik, jdoerfert

Reviewed By: steven_wu

Subscribers: dexonsmith, llvm-commits

Tags: #llvm, #clang, #sanitizers, #lldb, #libc, #openmp

Differential Revision: https://reviews.llvm.org/D66149

llvm-svn: 369579
2019-08-21 21:00:16 +00:00
Serge Guelton d1262a6e91 Be explicit about Windows coff name trailing character policy
It's okay to *not* copy the trailing zero of a windows section/symbol name.
This is compatible with strncpy behavior but gcc doesn't know that and
throws an invalid warning. Encode this behavior in a proper function.

Differential Revision: https://reviews.llvm.org/D66420

llvm-svn: 369501
2019-08-21 07:54:42 +00:00
Seiya Nuta 522377494b [yaml2obj/obj2yaml][MachO] Allow setting custom section data
Reviewers: alexshap, jhenderson, rupprecht

Reviewed By: alexshap, jhenderson

Subscribers: abrachet, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65799

llvm-svn: 369348
2019-08-20 08:49:07 +00:00
George Rimar 9d5e8a476f [Object/COFF.h] - Stop returning std::error_code in a few methods. NFCI.
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
2019-08-19 14:32:23 +00:00
Yonghong Song a8dad5c79b [BPF] Fix bpf llvm-objdump issues.
Commit https://reviews.llvm.org/D57939 ("[DWARF] Refactor
RelocVisitor and fix computation of SHT_RELA-typed relocation entries)
made a change for relocation resolution when operating
on an object file.

The change unfortunately broke BPF as given SymbolValue (S) and
Addent (A), previously relocation is resolved to
    S + A
and after the change, it is resolved to
    S

This patch fixed the issue by resolving relocation correctly.

It looks not all relocation resolution reaches here and I did not
trace down exactly when. But I do find if the object file includes
codes in two different ELF sections than default ".text",
the above bug will be triggered.

This patch included a trivial two function source code to
demonstrate this issue. The relocation for .debug_loc is resolved
incorrectly due to this and llvm-objdump cannot display source
annotated assembly.

Differential Revision: https://reviews.llvm.org/D66372

llvm-svn: 369199
2019-08-17 22:12:00 +00:00
Jonas Devlieghere 0eaee545ee [llvm] Migrate llvm::make_unique to std::make_unique
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
2019-08-15 15:54:37 +00:00
George Rimar bcc00e1afb Recommit r368812 "[llvm/Object] - Convert SectionRef::getName() to return Expected<>"
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
2019-08-14 11:10:11 +00:00
George Rimar 468919e182 Revert r368812 "[llvm/Object] - Convert SectionRef::getName() to return Expected<>"
It broke clang BB: http://lab.llvm.org:8011/builders/clang-x86_64-debian-fast/builds/16455

llvm-svn: 368813
2019-08-14 08:56:55 +00:00
George Rimar a0c6a35714 [llvm/Object] - Convert SectionRef::getName() to return Expected<>
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
2019-08-14 08:46:54 +00:00
Sean Fertile 29141da75e [XCOFF] Use a single symbolic constant for the size of an embeded name. [NFC]
Convert SymbolNameSize and SectionNameSize into just `NameSize`. The length of
a name embeded in a symbol table entry or section header table entry is length 8
for Sections, Symbols and Files. No need to have a distinct constant for each
one. Also removes the Size argument to 'generateStringRef' as the size is
always 'XCOFF::NameSize'.

llvm-svn: 368584
2019-08-12 15:27:40 +00:00
Sunil Srivastava 27f6f2f88b Print reasonable representations of type names in llvm-nm, readelf and readobj
For type values that do not have proper names, print reasonable representation
in llvm-nm, llvm-readobj and llvm-readelf, matching GNU tools.s

Fixes PR41713.

Differential Revision: https://reviews.llvm.org/D65537

llvm-svn: 368451
2019-08-09 16:54:51 +00:00
Igor Kudrin f26a70a5e7 Switch LLVM to use 64-bit offsets (2/5)
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
2019-08-06 10:49:40 +00:00
David Candler 7eacefedab [NFC] Test commit, corrected some spelling in comment
Test commit, corrected some spelling in comment.

Differential Revision: https://reviews.llvm.org/D65516

llvm-svn: 367685
2019-08-02 14:44:17 +00:00
Shoaib Meenai a67f6f1746 [Object] Add public MaxSectionAlignment to MachOUniversal
Change MAXSECTALIGN to a public MaxSectionAlignment in MachOUniversal.
Will be used in a follow-up.

Patch by Anusha Basana <anusha.basana@gmail.com>

Differential Revision: https://reviews.llvm.org/D65117

llvm-svn: 366969
2019-07-25 00:29:13 +00:00
Owen Reynolds 24f3e102a6 [llvm-ar] Fix support for archives with members larger than 4GB
llvm-ar outputs a strange error message when handling archives with
members larger than 4GB due to not checking file size when passing the
value as an unsigned 32 bit integer. This overflow issue caused
malformed archives to be created.:

https://bugs.llvm.org/show_bug.cgi?id=38058

This change allows for members above 4GB and will error in a case that
is over the formats size limit, a 10 digit decimal integer.

Differential Revision: https://reviews.llvm.org/D65093

llvm-svn: 366813
2019-07-23 14:44:21 +00:00
Sean Fertile 8034daca5f [Object][XCOFF] Remove extra includes from XCOFF related files. [NFC]
Differential Revision: https://reviews.llvm.org/D60885

llvm-svn: 366723
2019-07-22 18:47:55 +00:00
Hsiangkai Wang 18ccfadd46 [DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame.
It is necessary to generate fixups in .debug_frame or .eh_frame as
relaxation is enabled due to the address delta may be changed after
relaxation.

There is an opcode with 6-bits data in debug frame encoding. So, we
also need 6-bits fixup types.

Differential Revision: https://reviews.llvm.org/D58335

llvm-svn: 366524
2019-07-19 02:03:34 +00:00
Steven Wu dac7fca530 Remove the static initialize introduced in r365099
Summary:
Some polish for r365099 which adds a static initializer to
MachOObjectFile. Remove it by moving it to file scope.

Reviewers: smeenai, alexshap, compnerd, mtrent, anushabasana

Reviewed By: smeenai

Subscribers: hiraditya, jkorous, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64873

llvm-svn: 366496
2019-07-18 21:01:21 +00:00
Hsiangkai Wang 657277e0f1 Revert "[DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame."
This reverts commit 17e3cbf5fe656483d9016d0ba9e1d0cd8629379e.

llvm-svn: 366444
2019-07-18 15:06:50 +00:00
Hsiangkai Wang e43ce1a958 [DebugInfo] Generate fixups as emitting DWARF .debug_frame/.eh_frame.
It is necessary to generate fixups in .debug_frame or .eh_frame as
relaxation is enabled due to the address delta may be changed after
relaxation.

There is an opcode with 6-bits data in debug frame encoding. So, we
also need 6-bits fixup types.

Differential Revision: https://reviews.llvm.org/D58335

llvm-svn: 366442
2019-07-18 14:47:34 +00:00
Alex Bradbury 44deaf7e54 [DWARF][RISCV] Add support for RISC-V relocations needed for debug info
When code relaxation is enabled many RISC-V fixups are not resolved but
instead relocations are emitted. This happens even for DWARF debug
sections. Therefore, to properly support the parsing of DWARF debug info
we need to be able to resolve RISC-V relocations. This patch adds:

* Support for RISC-V relocations in RelocationResolver
* DWARF support for two relocations per object file offset
* DWARF changes to support relocations in more DIE fields

The two relocations per offset change is needed because some RISC-V
relocations (used for label differences) come in pairs.

Relocations can also be emitted for DWARF fields where relocations were
not yet evaluated. Adding relocation support for some of these fields is
essencial. On the other hand, LLVM currently emits RISC-V relocations
for fixups that could be safely evaluated, since they can never be
affected by code relaxations. This patch also adds relocation support
for the fields affected by those extraneous relocations (the DWARF unit
entry Length, and the DWARF debug line entry TotalLength and
PrologueLength), for testing purposes.

Differential Revision: https://reviews.llvm.org/D62062
Patch by Luís Marques.

llvm-svn: 366402
2019-07-18 05:22:55 +00:00
Fangrui Song 327db23b66 [Object] isNotObjectErrorInvalidFileType: simplify
llvm-svn: 365997
2019-07-13 09:28:33 +00:00
Fangrui Song 16ac7a5a27 [Object] isNotObjectErrorInvalidFileType: fix use-after-move
llvm-svn: 365996
2019-07-13 09:23:35 +00:00
Reid Kleckner cc418a3af4 [Support] Move llvm::MemoryBuffer to sys::fs::file_t
Summary:
On Windows, Posix integer file descriptors are a compatibility layer
over native file handles provided by the C runtime. There is a hard
limit on the maximum number of file descriptors that a process can open,
and the limit is 8192. LLD typically doesn't run into this limit because
it opens input files, maps them into memory, and then immediately closes
the file descriptor. This prevents it from running out of FDs.

For various reasons, I'd like to open handles to every input file and
keep them open during linking. That requires migrating MemoryBuffer over
to taking open native file handles instead of integer FDs.

Reviewers: aganea, Bigcheese

Reviewed By: aganea

Subscribers: smeenai, silvas, mehdi_amini, hiraditya, steven_wu, dexonsmith, dang, llvm-commits, zturner

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63453

llvm-svn: 365588
2019-07-10 00:34:13 +00:00
Sean Fertile 210314ae8c Try to appease the Windows build bots.
Several of the conditonal operators commited in llvm-svn: 365524 fail to compile
on the windows buildbots. Converting to an if and early return to try to fix.

llvm-svn: 365535
2019-07-09 18:44:28 +00:00
Sean Fertile 837ae69f8b [Object][XCOFF] Add support for 64-bit file header and section header dumping.
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
2019-07-09 18:09:11 +00:00
George Rimar d0921a4696 [Object/ELF.h] - Improve error reporting.
The errors coming from ELF.h are usually not very
useful because they are uninformative. This patch is a
first step to improve the situation.

I tested this patch with a run of check-llvm and found
that few messages are untested. In this patch, I did not
add more tests but marked all such cases with a "TODO" comment.

For all tested messages I extended the error text to
provide more details (see test cases changed).

Differential revision: https://reviews.llvm.org/D64014

llvm-svn: 365183
2019-07-05 11:28:49 +00:00
Shoaib Meenai 995798d2d5 [MachO] Add valid architecture function
Added array of valid architectures and function returning array.
Modified llvm-lipo to include list of valid architectures in error message for invalid arch.

Patch by Anusha Basana <anusha.basana@gmail.com>

Differential Revision: https://reviews.llvm.org/D63735

llvm-svn: 365099
2019-07-04 00:17:02 +00:00
Nico Weber 1dc2123d64 Share /machine: handling code with llvm-cvtres too
r363016 let lld-link and llvm-lib share the /machine: parsing code.
This lets llvm-cvtres share it as well.

Making llvm-cvtres depend on llvm-lib seemed a bit strange (it doesn't
need llvm-lib's dependencies on BinaryFormat and BitReader) and I
couldn't find a good place to put this code. Since it's just a few
lines, put it in lib/Object for now.

Differential Revision: https://reviews.llvm.org/D63120

llvm-svn: 363144
2019-06-12 11:32:43 +00:00
Nico Weber af6bc65ddf lld-link: Reject more than one resource .obj file
Users are exepcted to pass all .res files to the linker, which then
merges all the resource in all .res files into a tree structure and then
converts the final tree structure to a .obj file with .rsrc$01 and
.rsrc$02 sections and then links that.

If the user instead passes several .obj files containing such resources,
the correct thing to do would be to have custom code to merge the trees
in the resource sections instead of doing normal section merging -- but
link.exe rejects if multiple resource obj files are passed in with
LNK4078, so let lld-link do that too instead of silently writing broken
.rsrc sections in that case.

The only real way to run into this is if users manually convert .res
files to .obj files by running cvtres and then handing the resulting
.obj files to lld-link instead, which in practice likely never happens.

(lld-link is slightly stricter than link.exe now: If link.exe is passed
one .obj file created by cvtres, and a .res file, for some reason it
just emits a warning instead of an error and outputs strange looking
data. lld-link now errors out on mixed input like this.)

One way users could accidentally run into this is the following
scenario: If a .res file is passed to lib.exe, then lib.exe calls
cvtres.exe on the .res file before putting it in the output .lib.
(llvm-lib currently doesn't do this.)
link.exe's /wholearchive seems to only add obj files referenced from the
static library index, but lld-link current really adds all files in the
archive. So if lld-link /wholearchive is used with .lib files produced
by lib.exe and .res files were among the files handed to lib.exe, we
previously silently produced invalid output, but now we error out.

link.exe's /wholearchive semantics on the other hand mean that it
wouldn't load the resource object files from the .lib file at all.
Since this scenario is probably still an unlikely corner case,
the difference in behavior here seems fine -- and lld-link might have to
change to use link.exe's /wholearchive semantics in the future anyways.

Vaguely related to PR42180.

Differential Revision: https://reviews.llvm.org/D63109

llvm-svn: 363078
2019-06-11 15:22:28 +00:00
Nico Weber dd6019526d Let writeWindowsResourceCOFF() take a TimeStamp parameter
For lld, pass in Config->Timestamp (which is set based on lld's
/timestamp: and /Brepro flags). Since the writeWindowsResourceCOFF()
data is only used in-memory by LLD and the obj's timestamp isn't used
for anything in the output, this doesn't change behavior.

For llvm-cvtres, add an optional /timestamp: parameter, and use the
current behavior of calling time() if the parameter is not passed in.

This doesn't really change observable behavior (unless someone passes
/timestamp: to llvm-cvtres, which wasn't possible before), but it
removes the last unqualified call to time() from llvm/lib, which seems
like a good thing.

Differential Revision: https://reviews.llvm.org/D63116

llvm-svn: 363050
2019-06-11 11:26:50 +00:00
Alex Brachet c33944832c [MACHO] Replaced calls to getStruct with getStructOrErr in functions returning Error or Expected or similar
llvm-svn: 362526
2019-06-04 16:55:30 +00:00
Peter Smith 49d7221f71 [AArch64][ELF][llvm-readobj] Add support for BTI and PAC dynamic tags
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
2019-06-04 11:44:33 +00:00
Owen Reynolds 5d5078e341 [llvm-ar] Reapply Fix relative thin archive path handling
Includes a fix for an introduced build failure due to a post c++11 use of std::mismatch. 

This fixes some thin archive relative path issues, paths are shortened where possible and paths are output correctly when using the display table command.

Differential Revision: https://reviews.llvm.org/D59491

llvm-svn: 362484
2019-06-04 10:13:03 +00:00
Dmitri Gribenko 857de979a7 Revert "[llvm-ar] Fix relative thin archive path handling"
This reverts commit r362407.  It broke compilation of
llvm/lib/Object/ArchiveWriter.cpp:

error: type 'llvm::sys::path::const_iterator' does not provide a call
operator

llvm-svn: 362413
2019-06-03 16:21:37 +00:00
Owen Reynolds fade9cbed7 [llvm-ar] Fix relative thin archive path handling
This fixes some thin archive relative path issues, paths are shortened where possible and paths are output correctly when using the display table command.

Differential Revision: https://reviews.llvm.org/D59491

llvm-svn: 362407
2019-06-03 15:26:07 +00:00
Sjoerd Meijer 930dee2c0b [ARM] add target arch definitions for 8.1-M and MVE
This adds:
- LLVM subtarget features to make all the new instructions conditional on,
- CPU and FPU names for use on clang's command line, with default FPUs set
  so that "armv8.1-m.main+fp" and "armv8.1-m.main+fp.dp" will select the right
  FPU features,
- architecture extension names "mve" and "mve.fp",
- ABI build attribute support for v8.1-M (a new value for Tag_CPU_arch) and MVE
  (a new actual tag).

Patch mostly by Simon Tatham.

Differential Revision: https://reviews.llvm.org/D60698

llvm-svn: 362090
2019-05-30 12:57:04 +00:00
Peter Collingbourne 31fda09b2d Add IR support, ELF section and user documentation for partitioning feature.
The partitioning feature was proposed here:
http://lists.llvm.org/pipermail/llvm-dev/2019-February/130583.html

This is mostly just documentation. The feature itself will be contributed
in subsequent patches.

Differential Revision: https://reviews.llvm.org/D60242

llvm-svn: 361923
2019-05-29 03:29:01 +00:00
Simon Tatham 760df47b77 [ARM] Replace fp-only-sp and d16 with fp64 and d32.
Those two subtarget features were awkward because their semantics are
reversed: each one indicates the _lack_ of support for something in
the architecture, rather than the presence. As a consequence, you
don't get the behavior you want if you combine two sets of feature
bits.

Each SubtargetFeature for an FP architecture version now comes in four
versions, one for each combination of those options. So you can still
say (for example) '+vfp2' in a feature string and it will mean what
it's always meant, but there's a new string '+vfp2d16sp' meaning the
version without those extra options.

A lot of this change is just mechanically replacing positive checks
for the old features with negative checks for the new ones. But one
more interesting change is that I've rearranged getFPUFeatures() so
that the main FPU feature is appended to the output list *before*
rather than after the features derived from the Restriction field, so
that -fp64 and -d32 can override defaults added by the main feature.

Reviewers: dmgreen, samparker, SjoerdMeijer

Subscribers: srhines, javed.absar, eraman, kristof.beyls, hiraditya, zzheng, Petar.Avramovic, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D60691

llvm-svn: 361845
2019-05-28 16:13:20 +00:00
Jason Liu 9212206d25 [XCOFF] Implement parsing symbol table for xcoffobjfile and output as yaml format
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
2019-05-28 14:37:59 +00:00
Robert Widmann b0fd12b689 [LLVM-C] Add Accessor for Mach-O Universal Binary Slices
Summary: Allow for retrieving an object file corresponding to an architecture-specific slice in a Mach-O universal binary file.

Reviewers: whitequark, deadalnix

Reviewed By: whitequark

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60378

llvm-svn: 361705
2019-05-25 16:47:27 +00:00
Martin Storsjo de6038b265 [llvm-dlltool] Respect NONAME keyword
This adds proper handling of the NONAME-keyword, which makes llvm-dlltool
generate an import using the ordinal instead of the name.

Patch by by Jannik Vogel, test added by Stefan Schmidt.

Differential Revision: https://reviews.llvm.org/D62175

llvm-svn: 361367
2019-05-22 09:49:54 +00:00
Ben Dunbobbin 1d16515fb4 [ELF] Implement Dependent Libraries Feature
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
2019-05-17 03:44:15 +00:00
Pavel Labath 2d29e16c30 Minidump: Add support for the MemoryList stream
Summary:
the stream format is exactly the same as for ThreadList and ModuleList
streams, only the entry types are slightly different, so the changes in
this patch are just straight-forward applications of established
patterns.

Reviewers: amccarth, jhenderson, clayborg

Subscribers: markmentovai, lldb-commits, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61885

llvm-svn: 360908
2019-05-16 15:17:30 +00:00
Fangrui Song e183340c29 Recommit [Object] Change object::SectionRef::getContents() to return Expected<StringRef>
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
2019-05-16 13:24:04 +00:00
Hans Wennborg 4da9ff9fcf Revert r360876 "[Object] Change object::SectionRef::getContents() to return Expected<StringRef>"
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
2019-05-16 12:08:34 +00:00