Commit Graph

1402 Commits

Author SHA1 Message Date
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
Fangrui Song a076ec54be [Object] Change object::SectionRef::getContents() to return Expected<StringRef>
Expected<ArrayRef<uint8_t>> may be better but use Expected<StringRef> for now.

Follow-up of D61781.

llvm-svn: 360876
2019-05-16 11:33:48 +00:00
Tim Northover ff6875acd9 AArch64: support binutils-like things on arm64_32.
This adds support for the arm64_32 watchOS ABI to LLVM's low level tools,
teaching them about the specific MachO choices and constants needed to
disassemble things.

llvm-svn: 360663
2019-05-14 11:25:44 +00:00
Fangrui Song e1cb2c0f40 [Object] Change ObjectFile::getSectionContents to return Expected<ArrayRef<uint8_t>>
Change
std::error_code getSectionContents(DataRefImpl, StringRef &) const;
to
Expected<ArrayRef<uint8_t>> getSectionContents(DataRefImpl) const;

Many object formats use ArrayRef<uint8_t> as the underlying type, which
is generally better than StringRef to represent binary data, so change
the type to decrease the number of type conversions.

Reviewed By: ruiu, sbc100

Differential Revision: https://reviews.llvm.org/D61781

llvm-svn: 360648
2019-05-14 04:22:51 +00:00
Fangrui Song 93b6aa0751 [Object] Move ELF specific ObjectFile::getBuildAttributes to ELFObjectFileBase
Change the return type from std::error_code to Error and make the
function protected.

llvm-svn: 360416
2019-05-10 10:19:08 +00:00
Fangrui Song e357ca8231 [Object] Change SymbolicFile::printSymbolName to use Error
llvm-svn: 360414
2019-05-10 09:59:04 +00:00
Sean Fertile fd75ee9154 [Object][XCOFF] Add an XCOFF dumper for llvm-readobj.
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
2019-05-03 12:57:07 +00:00
Nico Weber 81862f82ee lld-link: Add /force:multipleres extension to make dupe resource diag non-fatal
As a side benefit, lld-link now reports more than one duplicate resource
entry before exiting with an error even if the new flag is not passed.

llvm-svn: 359829
2019-05-02 21:21:55 +00:00
Fangrui Song 8be28cdc52 [Object] Change getSectionName() to return Expected<StringRef>
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
2019-05-02 10:32:03 +00:00
Pavel Labath cfc4519ef3 Object/Minidump: Add support for the ThreadList stream
Summary:
The stream contains the list of threads belonging to the process
described by the minidump. Its structure is the same as the ModuleList
stream, and in fact, I have generalized the ModuleList reading code to
handle this stream too.

Reviewers: amccarth, jhenderson, clayborg

Subscribers: llvm-commits, lldb-commits, markmentovai, zturner

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61064

llvm-svn: 359762
2019-05-02 07:45:42 +00:00
Nico Weber 413517ecfe lld-link: Make "duplicate resource" error message a bit more concise
Reduces the error message from:
    lld-link: error: failed to parse .res file: duplicate resource: type STRINGTABLE (ID 6)/name ID 3/language 1033, in test1.res and in test2.res

To:
    lld-link: error: duplicate resource: type STRINGTABLE (ID 6)/name ID 3/language 1033, in test1.res and in test2.res

Make sure every error message emitted by cvtres contains the name of at
least one ".res" file, so that removing the "failed to parse .res file"
string doesn't lose information.

Differential Revision: https://reviews.llvm.org/D61388

llvm-svn: 359749
2019-05-02 01:52:24 +00:00
Simon Pilgrim 4559739f7c Remove duplicate line. NFCI.
Reported in https://www.viva64.com/en/b/0629/

llvm-svn: 359483
2019-04-29 18:58:32 +00:00
Nico Weber cf6267cecb llvm-cvtres: Attempt to make llvm-cvtres/duplicate.test work on big-endian systems
llvm-svn: 359414
2019-04-29 00:51:41 +00:00
Sean Fertile a93a33cb87 [Object][XCOFF] Add intial support for section header table.
Adds a representation of the section header table to XCOFFObjectFile,
and implements enough to dump the section headers with llvm-obdump.

Differential Revision: https://reviews.llvm.org/D60784

llvm-svn: 359244
2019-04-25 21:36:04 +00:00
Nico Weber 23cb79ff93 llvm-cvtres: Make new dupe resource error a bit friendlier
For well-known type IDs, include the name of the type.

To not duplicate the ID->name map, make llvm-readobj call this new
function as well.  It has slightly different output, so this also
requires updating a few tests.

Differential Revision: https://reviews.llvm.org/D61086

llvm-svn: 359153
2019-04-24 23:26:30 +00:00
Nico Weber ccf096463a Let llvm-cvtres (and lld-link) report duplicate resources
If two .res files contain the same resource, cvtres.exe (and hence
link.exe) reject the input with this message:

    CVTRES : fatal error CVT1100: duplicate resource.  type:STRING, name:101, language:0x0409
    LINK : fatal error LNK1123: failure during conversion to COFF: file invalid or corrupt

llvm-cvtres (and lld-link) used to silently pick one of the duplicate
resources instead. This patch makes them report an error as well.
We slightly improve on cvtres by printing the name of two .res files
containing duplicate entries as well.

Differential Revision: https://reviews.llvm.org/D61049

llvm-svn: 359083
2019-04-24 11:42:59 +00:00
Nico Weber 6967da8ffa llvm-cvtres: Split addChild(ID) into two functions
Before, there was an IsData parameter. Now, there are two different
functions for data nodes and ID nodes. No behavior change, needed for a
follow-up change to make two data nodes (but not two ID nodes) with the
same ID an error.

For consistency, rename another addChild() overload to addNameChild().

llvm-svn: 359024
2019-04-23 18:46:53 +00:00
Sam Clegg fe8aabf9d9 [WebAssembly] Object: Improve error messages on invalid section
Also add a test.

Differential Revision: https://reviews.llvm.org/D60836

llvm-svn: 358801
2019-04-20 00:11:46 +00:00
Thomas Lively fef8de66a6 [WebAssembly] Add DataCount section to object files
Summary:
This ensures that object files will continue to validate as
WebAssembly modules in the presence of bulk memory operations. Engines
that don't support bulk memory operations will not recognize the
DataCount section and will report validation errors, but that's ok
because object files aren't supposed to be run directly anyway.

Reviewers: aheejin, dschuff, sbc100

Subscribers: jgravelle-google, hiraditya, sunfish, rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60623

llvm-svn: 358315
2019-04-12 22:27:48 +00:00
Robert Widmann d1ba3b13f8 [LLVM-C] Add Section and Symbol Iterator Accessors for Object File Binaries
Summary: This brings us to full feature parity with the old API, so I've deprecated it and updated the tests.  I'll do a follow-up patch to do some more cleanup and documentation work in this header.

Reviewers: whitequark, deadalnix

Reviewed By: whitequark

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60407

llvm-svn: 358037
2019-04-09 21:53:31 +00:00
Pavel Labath aaff480c68 Object/Minidump: Add support for reading the ModuleList stream
Summary:
The ModuleList stream consists of an integer giving the number of
entries in the list, followed by the list itself. Each entry in the list
describes a module (dynamically loaded objects which were loaded in the
process when it crashed (or when the minidump was generated).

The code for reading the list is relatively straight-forward, with a
single gotcha. Some minidump writers are emitting padding after the
"count" field in order to align the subsequent list on 8 byte boundary
(this depends on how their ModuleList type was defined and the native
alignment of various types on their platform). Fortunately, the minidump
format contains enough redundancy (in the form of the stream length
field in the stream directory), which allows us to detect this situation
and correct it.

This patch just adds the ability to parse the stream. Code for
conversion to/from yaml will come in a follow-up patch.

Reviewers: zturner, amccarth, jhenderson, clayborg

Subscribers: jdoerfert, markmentovai, lldb-commits, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60121

llvm-svn: 357897
2019-04-08 09:57:29 +00:00
Robert Widmann a51883cfab [LLVM-C] Allow Access to the Type of a Binary
Summary:  Add an accessor for the type of a binary file.

Reviewers: whitequark, deadalnix

Reviewed By: whitequark

Subscribers: hiraditya, aheejin, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60366

llvm-svn: 357872
2019-04-07 18:18:42 +00:00
Fangrui Song 6a0746a92f Change some StringRef::data() reinterpret_cast to bytes_begin() or arrayRefFromStringRef()
llvm-svn: 357852
2019-04-07 03:58:42 +00:00
Robert Widmann c76b621530 [LLVM-C] Begin to Expose A More General Binary Interface
Summary:
Provides a new type, `LLVMBinaryRef`, and a binding to `llvm::object::createBinary` for more general interoperation with binary files than `LLVMObjectFileRef`.  It also provides the proper non-consuming API for input buffers and populates an out parameter for error handling if necessary - two things the previous API did not do.

In a follow-up, I'll define section and symbol iterators and begin to build upon the existing test infrastructure.

This patch is a first step towards deprecating that API and replacing it with something more robust.

Reviewers: deadalnix, whitequark

Reviewed By: whitequark

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60322

llvm-svn: 357822
2019-04-05 21:36:50 +00:00
Pavel Labath ebdc698dbc Fix r357749 for big-endian architectures
We need to read the strings from the minidump files as little-endian,
regardless of the host byte order.

I definitely remember thinking about this case while writing the patch
(and in fact, I have implemented that for the "write" case), but somehow
I have ended up not implementing the byte swapping when reading the
data. This adds the necessary byte-swapping and should hopefully fix
test failures on big-endian bots.

llvm-svn: 357754
2019-04-05 08:43:54 +00:00
Pavel Labath 51d9fa0a22 Minidump: Add support for reading/writing strings
Summary:
Strings in minidump files are stored as a 32-bit length field, giving
the length of the string in *bytes*, which is followed by the
appropriate number of UTF16 code units. The string is also supposed to
be null-terminated, and the null-terminator is not a part of the length
field. This patch:
- adds support for reading these strings out of the minidump file (this
  implementation does not depend on proper null-termination)
- adds support for writing them to a minidump file
- using the previous two pieces implements proper (de)serialization of
  the CSDVersion field of the SystemInfo stream. Previously, this was
  only read/written as hex, and no attempt was made to access the
  referenced string -- now this string is read and written correctly.

The changes are tested via yaml2obj|obj2yaml round-trip as well as a
unit test which checks the corner cases of the string deserialization
logic.

Reviewers: jhenderson, zturner, clayborg

Subscribers: llvm-commits, aprantl, markmentovai, amccarth, lldb-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59775

llvm-svn: 357749
2019-04-05 08:06:26 +00:00
Sam Clegg 2a7cac932b [WebAssembly] Add new explicit relocation types for PIC relocations
See https://github.com/WebAssembly/tool-conventions/pull/106

Differential Revision: https://reviews.llvm.org/D59907

llvm-svn: 357710
2019-04-04 17:43:50 +00:00
Joseph Tremoulet 9f598ac706 [COFF] Fix delay import directory iterator
Summary:
Take the Index into account in `getDelayImportTable`, otherwise we
always return the entry for the first delay DLL reference.

Reviewers: ruiu

Reviewed By: ruiu

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60081

llvm-svn: 357697
2019-04-04 14:13:28 +00:00
Hubert Tong ab2eb2bfac [XCOFF] Add functionality for parsing AIX XCOFF object file headers
Summary:
1. Add functionality for parsing AIX XCOFF object files headers.
2. Only support 32-bit AIX XCOFF object files in this patch.
3. Print out the AIX XCOFF object file header in YAML format.

Reviewers: sfertile, hubert.reinterpretcast, jasonliu, mstorsjo, zturner, rnk

Reviewed By: sfertile, hubert.reinterpretcast

Subscribers: jsji, mgorny, hiraditya, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59419

Patch by Digger Lin

llvm-svn: 357663
2019-04-04 00:53:21 +00:00
Sam Clegg 492f752969 [WebAssembly] Initial implementation of PIC code generation
This change implements lowering of references global symbols in PIC
mode.

This change implements lowering of global references in PIC mode using a
new @GOT reference type. @GOT references can be used with function or
data symbol names combined with the get_global instruction. In this case
the linker will insert the wasm global that stores the address of the
symbol (either in memory for data symbols or in the wasm table for
function symbols).

For now I'm continuing to use the R_WASM_GLOBAL_INDEX_LEB relocation
type for this type of reference which means that this relocation type
can refer to either a global or a function or data symbol. We could
choose to introduce specific relocation types for GOT entries in the
future.  See the current dynamic linking proposal:

https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md

Differential Revision: https://reviews.llvm.org/D54647

llvm-svn: 357022
2019-03-26 19:46:15 +00:00
Martin Storsjo 146db4405c [llvm-dlltool] Set a proper machine type for weak symbol object files
This makes GNU binutils not reject the libraries outright.

GNU ld handles weak externals slightly differently though, so it
can't use them for aliases in import libraries, but this makes GNU
ld able to use the rest of the import libraries.

LLD accepted object files with machine type 0 aka
IMAGE_FILE_MACHINE_UNKNOWN.

Differential Revision: https://reviews.llvm.org/D59742

llvm-svn: 356982
2019-03-26 09:02:44 +00:00
Fangrui Song 4597dce483 [DWARF] Refactor RelocVisitor and fix computation of SHT_RELA-typed relocation entries
Summary:
getRelocatedValue may compute incorrect value for SHT_RELA-typed relocation entries.

// DWARFDataExtractor.cpp
uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint32_t *Off,
...
  // This formula is correct for REL, but may be incorrect for RELA if the value
  // stored in the location (getUnsigned(Off, Size)) is not zero.
  return getUnsigned(Off, Size) + Rel->Value;

In this patch, we

* refactor these visit* functions to include a new parameter `uint64_t A`.
  Since these visit* functions are no longer used as visitors, rename them to resolve*.
  + REL: A is used as the addend. A is the value stored in the location where the
    relocation applies: getUnsigned(Off, Size)
  + RELA: The addend encoded in RelocationRef is used, e.g. getELFAddend(R)
* and add another set of supports* functions to check if a given relocation type is handled.
  DWARFObjInMemory uses them to fail early.

Reviewers: echristo, dblaikie

Reviewed By: echristo

Subscribers: mgorny, aprantl, aheejin, fedor.sergeev, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57939

llvm-svn: 356729
2019-03-22 02:43:11 +00:00
Steven Wu 5a59354760 [Object] Fix reading objects created with -fembed-bitcode-marker
Currently, this fails with many tools, e.g.

$ clang -fembed-bitcode-marker -c -o test.o test.c
$ nm test.o
nm: test.o The file was not recognized as a valid object file

-fembed-bitcode-marker creates a LLVM,bitcode section consisting of a single
byte. When reading the object file, IRObjectFile::findBitcodeInObject succeeds,
causing SymbolicFile::createSymbolicFile to try to read the "bitcode" rather
than using the outer Mach-O data - when then fails.

Fix this by making findBitcodeInObject return an error if the section size <= 1.

Patched by: Nicholas Allegra

Differential Revision: https://reviews.llvm.org/D44373

llvm-svn: 356718
2019-03-21 21:01:31 +00:00
Pavel Labath 581d79a440 [Object] Add basic minidump support
Summary:
This patch adds basic support for reading minidump files. It contains
the definitions of various important minidump data structures (header,
stream directory), and of one minidump stream (SystemInfo). The ability
to read other streams will be added in follow-up patches. However, all
streams can be read even now as raw data, which means lldb's minidump
support (where this code is taken from) can be immediately rebased on
top of this patch as soon as it lands.

As we don't have any support for generating minidump files (yet), this
tests the code via unit tests with some small handcrafted binaries in
the form of c char arrays.

Reviewers: Bigcheese, jhenderson, zturner

Subscribers: srhines, dschuff, mgorny, fedor.sergeev, lemo, clayborg, JDevlieghere, aprantl, lldb-commits, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59291

llvm-svn: 356652
2019-03-21 09:18:59 +00:00
Michael Trent 02a2ce9a4b Fix Mach-O bind and rebase validation errors in libObject
Summary:
llvm-objdump (via libObject) validates DYLD_INFO rebase and bind
entries against the basic structure found in the Mach-O file before
evaluating the contents of those entries. Certain malformed Mach-Os can
defeat the validation check and force llvm-objdump (libObject) to crash.

The previous logic verified a rebase or bind started in a valid Mach-O
section, but did not verify that the section wholely contained the
fixup. It also generally allows rebases or binds to start immediately
after a valid section even if that range is not itself part of a valid
section. Finally, bind and rebase opcodes that indicate more than one
fixup (apply N times...) are not completely validated: only the first
and final fixups are checked.

The previous logic also rejected certain binaries as false positives.
Some bind and rebase opcodes can modify the state machine such that the
next bind or rebase will fail. libObject will reject these opcodes as
invalid in order to be helpful and print an error message associated
with the instruction that caused the problem, even though the binary is
not actually illegal until it consumes the invalid state in the state
machine. In other words, libObject may reject a Mach-O binary that
Apple's dynamic linker may consider legal. The original version of
macho-rebase-add-addr-uleb-too-big is an example of such a binary.

I have replaced the existing checkSegAndOffset and checkCountAndSkip
functions with a single function, checkSegAndOffsets, which validates
all of the fixups realized by a DYLD_INFO opcode. checkSegAndOffsets
verifies that a Mach-O section fully contains each fixup. Every fixup
realized by an opcode is validated, and some (but not all!)
inconsistencies in the state machine are allowed until a fixup is
realized. This means that libObject may fail on an opcode that realizes
a fixup, not on the opcode that introduced the arithmetic error.

Existing test cases have been modified to reflect the changes in error
messages returned by libObject. What's more, the test case for 
macho-rebase-add-addr-uleb-too-big has been modified so that it actually
triggers the error condition; the new code in libObject considers the
original test binary "legal".

rdar://47797757

Reviewers: lhames, pete, ab

Reviewed By: pete

Subscribers: rupprecht, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59574

llvm-svn: 356629
2019-03-20 23:21:16 +00:00
Thomas Lively f6f4f84378 [WebAssembly] Target features section
Summary:
Implements a new target features section in assembly and object files
that records what features are used, required, and disallowed in
WebAssembly objects. The linker uses this information to ensure that
all objects participating in a link are feature-compatible and records
the set of used features in the output binary for use by optimizers
and other tools later in the toolchain.

The "atomics" feature is always required or disallowed to prevent
linking code with stripped atomics into multithreaded binaries. Other
features are marked used if they are enabled globally or on any
function in a module.

Future CLs will add linker flags for ignoring feature compatibility
checks and for specifying the set of allowed features, implement using
the presence of the "atomics" feature to control the type of memory
and segments in the linked binary, and add front-end flags for
relaxing the linkage policy for atomics.

Reviewers: aheejin, sbc100, dschuff

Subscribers: jgravelle-google, hiraditya, sunfish, mgrang, jfb, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59173

llvm-svn: 356610
2019-03-20 20:26:45 +00:00
Sam Clegg a688a42cdd [WebAssembly] Improve support for "needed" list in dylink section
This change adds basic support for shared library dependencies
via the dylink section.

See https://github.com/WebAssembly/tool-conventions/pull/77

Differential Revision: https://reviews.llvm.org/D59237

llvm-svn: 356102
2019-03-13 21:29:20 +00:00
Jonas Hahnfeld c64d73cce2 [ELF] Fix GCC8 warnings about "fall through", NFCI
Add break statements in Object/ELF.cpp since the code should consider the
generic tags for Hexagon, MIPS, and PPC. Add a test (copied from llvm-readobj)
to show that this works correctly (earlier versions of this patch would have
asserted).

The warnings in X86ELFObjectWriter.cpp are actually false-positives since
the nested switch() handles all possible values and returns in all cases.
Make this explicit by adding llvm_unreachable's.

Differential Revision: https://reviews.llvm.org/D58837

llvm-svn: 356037
2019-03-13 10:38:17 +00:00
Michael Trent 76d66123b2 Detect malformed LC_LINKER_COMMANDs in Mach-O binaries
Summary:
llvm-objdump can be tricked into reading beyond valid memory and
segfaulting if LC_LINKER_COMMAND strings are not null terminated. libObject
does have code to validate the integrity of the LC_LINKER_COMMAND struct,
but this validator improperly assumes linker command strings are null
terminated.

The solution is to report an error if a string extends beyond the end of
the LC_LINKER_COMMAND struct.

Reviewers: lhames, pete

Reviewed By: pete

Subscribers: rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59179

llvm-svn: 355851
2019-03-11 18:29:25 +00:00
Sunil Srivastava ae8fe4e093 Improve "llvm-nm -f sysv" output for Elf files
Specifically, compute and Print Type and Section columns.

This is a re-commit of rL354833, after fixing the Asan problem found a a buildbot.

Differential Revision: https://reviews.llvm.org/D59060

llvm-svn: 355742
2019-03-08 22:00:50 +00:00
Xing GUO b285878907 [llvm-objdump] Should print unknown d_tag in hex format
Summary:
Currently, `llvm-objdump` prints "unknown" instead of d_tag value in hex format. Because getDynamicTagAsString returns "unknown" rather than empty 
string.

Reviewers: grimar, jhenderson

Reviewed By: jhenderson

Subscribers: rupprecht, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58763

llvm-svn: 355262
2019-03-02 04:20:28 +00:00
Vlad Tsyrklevich c6d54ae9da Revert "Improve "llvm-nm -f sysv" output for Elf files"
This reverts commit r354833, it was causing ASan test failures on
sanitizer-x86_64-linux-fast.

llvm-svn: 354849
2019-02-26 07:04:56 +00:00
Sunil Srivastava d72d16f444 Improve "llvm-nm -f sysv" output for Elf files
Specifically, compute and Print Type and Section columns.

Differential Revision: https://reviews.llvm.org/D58263

llvm-svn: 354833
2019-02-26 00:19:39 +00:00