An archive looks like
<header>
<symbol table>
<tail>
The symbol table refers to offsets in the tail. A complication is that
we would like to support symbol tables that use 64 bit offsets if it
turns out that any of the offsets is too big.
This patch changes the archive writer to first compute the tail. We
cannot just compute one big StringRef since that would require reading
every member upfront, but we can represent it as a series of
StringRefs.
Having done that it is much easier to compute the symbol table and all
offsets are computed before it is written. With this if there is an
accounting problem it will show up with a regular symbol table, not
just when a 64 bit one is needed.
llvm-svn: 314844
Previously these were being included as both imports and
exports, with the import being satisfied by the export
(or some strong symbol) at runtime. However proved
unnecessary and actually complicated linking as it meant
there was not a 1-to-1 mapping between a wasm function
/global index and a linker symbol.
Differential Revision: https://reviews.llvm.org/D38246
llvm-svn: 314245
It is useful for the symbol to contain the index of the
function of global it represents in the function/global
index space.
For imports we also store the import index so that the
linker can find, for example, the signature of the
corresponding function, which is defined by the import
In the long run we need to decide whether this API
surface should be closer to binary (where imported
functions are seperate) or the wasm spec (where the
function index space is unified).
Differential Revision: https://reviews.llvm.org/D38189
llvm-svn: 314230
When dsymutil generates the companion file, its strips all unnecessary
sections by omitting their body and setting the offset in their
corresponding load command to zero.
One such section is the .eh_frame section, as it contains runtime
information rather than debug information and is part of the __TEXT
segment. When reading this section, we would just read the number of
bytes specified in the load command, starting from offset 0 (i.e. the
beginning of the file).
Rather than trying to parse this obviously invalid section, dwarfdump
now skips this.
Differential revision: https://reviews.llvm.org/D38135
llvm-svn: 314208
Summary:
This manifested itself in lld since it meant that weak
symbols were not appearing in archive symbol tables.
Subscribers: jfb, dschuff, jgravelle-google, aheejin
Differential Revision: https://reviews.llvm.org/D38111
llvm-svn: 313838
Add adds support for naming data segments. This is useful
useful linkers so that they can merge similar sections.
Differential Revision: https://reviews.llvm.org/D37886
llvm-svn: 313795
This patch renames K_MIPS64 to K_GNU64 as part of a change to add
support for writing archives with 64-bit indexes in the symbol table.
llvm-svn: 313787
Add adds support for naming data segments. This is useful
useful linkers so that they can merge similar sections.
Differential Revision: https://reviews.llvm.org/D37886
llvm-svn: 313692
Move logic that allows for Triple deduction from an ObjectFile object
out of llvm-objdump.cpp into a public factory, found in the ObjectFile
class.
This should allow other tools in the future to use this logic without
reimplementation.
Patch by Mitch Phillips
Differential Revision: https://reviews.llvm.org/D37719
llvm-svn: 313605
This change only treats imported and exports functions and globals
as symbol table entries the object has a "linking" section (i.e. it is
relocatable object file).
In this case all globals must be of type I32 and initialized with
i32.const. This was previously being assumed but not checked for and
was causing a failure on big endian machines due to using the wrong
value of then union.
See: https://bugs.llvm.org/show_bug.cgi?id=34487
Differential Revision: https://reviews.llvm.org/D37497
llvm-svn: 312674
The code wasn't previously taking into account that the
global index space is not same as the into in the Globals
array since the latter does not include imported globals.
This fixes the WebAssembly waterfall failures.
Differential Revision: https://reviews.llvm.org/D37384
llvm-svn: 312340
writeArchive returned a pair, but the first element of the pair is always
its first argument on failure, so it doesn't make sense to return it from
the function. This patch change the return type so that it does't return it.
Differential Revision: https://reviews.llvm.org/D37313
llvm-svn: 312177
Summary:
Previously, llvm-cvtres crashes on .res files which are empty except for
the null header. This allows the library to simply pass over them.
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D37044
llvm-svn: 311625
When creating an import library from lld, the cases with
Name != ExtName shouldn't end up as a weak alias, but as a real
export of the new name, which is what actually is exported from
the DLL.
This restores the behaviour of renamed exports to what it was in
4.0.
The other half of this commit, including test, goes into lld.
Differential Revision: https://reviews.llvm.org/D36633
llvm-svn: 310991
Hook up the -k option (that in the original GNU dlltool removes the
@n suffix from the symbol that the final executable ends up linked to).
In llvm-dlltool, make sure that functions end up with the undecorate
name type if this option is set and they are decorated. In mingw, when
creating import libraries from def files instead of creating an import
library as a side effect of linking a DLL, the symbol names in the def
contain the stdcall/fastcall decoration (but no leading underscore).
By setting the undecorate name type, a linker linking to the import
library will omit the decoration from the DLL import entry.
With this in place, mingw-w64 for i386 built with llvm-dlltool/clang
produces import libraries that actually work.
Differential Revision: https://reviews.llvm.org/D36548
llvm-svn: 310990
The previous Name and ExtName aren't enough to convey all the nuances
between weak aliases and stdcall decorated function names.
A test for this will be added in LLD.
Differential Revision: https://reviews.llvm.org/D36544
llvm-svn: 310988
Summary:
isThumb returns true for Thumb triples (little and big endian), isARM
returns true for ARM triples (little and big endian).
There are a few more checks using arm/thumb that are not covered by
those functions, e.g. that the architecture is either ARM or Thumb
(little endian) or ARM/Thumb little endian only.
Reviewers: javed.absar, rengolin, kristof.beyls, t.p.northover
Reviewed By: rengolin
Subscribers: llvm-commits, aemerson
Differential Revision: https://reviews.llvm.org/D34682
llvm-svn: 310781
I was surprised to see the code model being passed to MC. After all,
it assembles code, it doesn't create it.
The one place it is used is in the expansion of .cfi directives to
handle .eh_frame being more that 2gb away from the code.
As far as I can tell, gnu assembler doesn't even have an option to
enable this. Compiling a c file with gcc -mcmodel=large produces a
regular looking .eh_frame. This is probably because in practice linker
parse and recreate .eh_frames.
In llvm this is used because the JIT can place the code and .eh_frame
very far apart. Ideally we would fix the jit and delete this
option. This is hard.
Apart from confusion another problem with the current interface is
that most callers pass CodeModel::Default, which is bad since MC has
no way to map it to the target default if it actually needed to.
This patch then replaces the argument with a boolean with a default
value. The vast majority of users don't ever need to look at it. In
fact, only CodeGen and llvm-mc use it and llvm-mc just to enable more
testing.
llvm-svn: 309884
Previously, the created object files for the import library were broken.
Write the symbol table before the string table. Simplify the code by
using a separate variable Prefix instead of duplicating a few lines.
Also update the coff-weak-exports to actually check that the generated
weak symbols can be found as intended.
Differential Revision: https://reviews.llvm.org/D36065
llvm-svn: 309555
This diff removes the second argument of the method MachOObjectFile::exports.
In all in-tree uses this argument is equal to "this" and
without this argument the interface seems to be cleaner.
Test plan: make check-all
llvm-svn: 309462
Summary:
ELF linkers generate __start_<secname> and __stop_<secname> symbols
when there is a value in a section <secname> where the name is a valid
C identifier. If dead stripping determines that the values declared
in section <secname> are dead, and we then internalize (and delete)
such a symbol, programs that reference the corresponding start and end
section symbols will get undefined reference linking errors.
To fix this, add the section name to the IRSymtab entry when a symbol is
defined in a specific section. Then use this in the gold-plugin to mark
the symbol as external and visible from outside the summary when the
section name is a valid C identifier.
Reviewers: pcc
Subscribers: mehdi_amini, inglorion, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D35639
llvm-svn: 309009
entries in libObject (done in r308690). In the case when the last node
has no children setting State.Current = Children + 1; where that would be past
Trie.end() is actually ok since the pointer is not used with zero children.
rdar://33490512
llvm-svn: 308924
lld needs a matching change for this will be my next commit.
Expect it to fail build until that matching commit is picked up by the bots.
Like the changes in r296527 for dyld bind entires and the changes in
r298883 for lazy bind, weak bind and rebase entries the export
entries are the last of the dyld compact info to have error handling added.
This follows the model of iterators that can fail that Lang Hanes
designed when fixing the problem for bad archives r275316 (or r275361).
So that iterating through the exports now terminates if there is an error
and returns an llvm::Error with an error message in all cases for malformed
input.
This change provides the plumbing for the error handling, all the needed
testing of error conditions and test cases for all of the unique error messages.
llvm-svn: 308690
Preserve the actual library name as provided by the user. This is
required to properly replicate link's behaviour about the module import
name handling. This requires an associated change to lld for updating
the tests for the proper behaviour for the import library module name
handling in various cases.
Associated tests will be part of the lld change.
llvm-svn: 308406
When I originally wrote this code, I neglected the fact that the import
library may be created for executables. This name is not the name of
the DLL, but rather the name for the imported module. It will be
embedded into the IAT/ILT reference. Rename it to make it more obvious.
NFC.
llvm-svn: 308384
When given an extension as part of the `library` directive in a def
file, the extension is preserved/honoured by link/lib. Behave similarly
when parsing the def file. This requires checking if a native extension
is provided as a keyword parameter. If no extension is present, append
a standard `.dll` or `.exe` extension.
This is best tested via lld, and I will add tests there as a follow up.
llvm-svn: 308383
Rafael Espindola