Commit Graph

1130 Commits

Author SHA1 Message Date
Simon Atanasyan 253125af03 [Mips] Reject R_MIPS_CALL16 against local symbols
llvm-svn: 240765
2015-06-26 07:25:20 +00:00
Simon Atanasyan b7bcff8796 [Mips] Create LA25 stubs for all branch relocations
llvm-svn: 240763
2015-06-26 07:25:06 +00:00
Rui Ueyama 923cb64801 COFF: Add a test for r240719.
llvm-svn: 240758
2015-06-26 03:50:27 +00:00
Rui Ueyama 32f8e1cb4e COFF: Change symbol resolution order for entry and /include.
We were resolving entry symbols and /include'd symbols after all other
symbols are resolved. But looks like it's too late. I found that it
causes some program to fail to link.

Let's say we have an object file A which defines symbols X and Y in an
archive. We also have another file B after A which defines X, Y and
_DLLMainCRTStartup in another archive. They conflict each other, so
either A or B can be linked.

If we have _DLLMainCRTStartup as an undefined symbol, file B is always
chosen. If not, there's a chance that A is chosen. If the linker
find it needs _DllMainCRTStartup after that, it's too late.

This patch adds undefined symbols to the symbol table as soon as
possible to fix the issue.

llvm-svn: 240757
2015-06-26 03:44:00 +00:00
Rui Ueyama ccde19d77e COFF: Fix local absolute symbols.
Absolute symbols were always handled as external symbols, so if two
or more object files define the same absolute symbol, they would
conflict even if the symbol is private to each file.
This patch fixes that bug.

llvm-svn: 240756
2015-06-26 03:09:23 +00:00
Rui Ueyama a29948873f COFF: Don't read non-x64 object files.
Currently the new LLD supports only x86-64.

llvm-svn: 240749
2015-06-26 00:42:21 +00:00
Rui Ueyama f799edef28 COFF: Rename /opt:icf -> /opt:lldicf.
ICF implemented in LLD is so experimental that we don't want to
enable that even if /opt:icf option is passed. I'll rename it back
once the feature is complete.

llvm-svn: 240721
2015-06-25 23:26:58 +00:00
Rui Ueyama 5817ebb0c8 COFF: Fix lexer for the module-definition file.
Previously it would hang if there's a stray punctuation (e.g. ?).

llvm-svn: 240697
2015-06-25 21:06:00 +00:00
Rafael Espindola 69e942aefe Update for llvm change.
llvm-svn: 240658
2015-06-25 17:04:12 +00:00
Rui Ueyama 88e0f9206b COFF: Fix a bug of __imp_ symbol.
The change I made in r240620 was not correct. If a symbol foo is
defined, and if you use __imp_foo, __imp_foo symbol is automatically
defined as a pointer (not just an alias) to foo.

Now that we need to create a chunk for automatically-created symbols.
I defined LocalImportChunk class for them.

llvm-svn: 240622
2015-06-25 03:31:47 +00:00
Rui Ueyama d766653534 COFF: Handle undefined symbols starting with __imp_ in a special way.
MSVC linker is able to link an object file created from the following code.
Note that __imp_hello is not defined anywhere.

  void hello() { printf("Hello\n"); }
  extern void (*__imp_hello)();
  int main() { __imp_hello(); }

Function symbols exported from DLLs are automatically mangled by appending
__imp_ prefix, so they have two names (original one and with the prefix).
This "feature" seems to simulate that behavior even for non-DLL symbols.

This is in my opnion very odd feature. Even MSVC linker warns if you use this.
I'm adding that anyway for the sake of compatibiltiy.

llvm-svn: 240620
2015-06-25 02:21:44 +00:00
Adhemerval Zanella 3ebea27d66 [ELF] Fix .init_array initialization
Some compilers may not add the section symbol in '.symtab' for the
.init_array and 'ldd' just ignore it.  It results in global constructor
not being called in final executable.

This patch add both '.init_array' and '.fini_array' to be added in
Atom graph generation even when the section contains no symbol.  An
already existing testcase is modified to check for such scenario.

The issue fixes the llvm test-suite regressions for both Single
and MultiSource files.

llvm-svn: 240570
2015-06-24 19:26:00 +00:00
Rui Ueyama ddf71fc370 COFF: Initial implementation of Identical COMDAT Folding.
Identical COMDAT Folding (ICF) is an optimization to reduce binary
size by merging COMDAT sections that contain the same metadata,
actual data and relocations. MSVC link.exe and many other linkers
have this feature. LLD achieves on per with MSVC in terms produced
binary size with this patch.

This technique is pretty effective. For example, LLD's size is
reduced from 64MB to 54MB by enaling this optimization.

The algorithm implemented in this patch is extremely inefficient.
It puts all COMDAT sections into a set to identify duplicates.
Time to self-link with/without ICF are 3.3 and 320 seconds,
respectively. So this option roughly makes LLD 100x slower.
But it's okay as I wanted to achieve correctness first.
LLD is still able to link itself with this optimization.
I'm going to make it more efficient in followup patches.

Note that this optimization is *not* entirely safe. C/C++ require
different functions have different addresses. If your program
relies on that property, your program wouldn't work with ICF.
However, it's not going to be an issue on Windows because MSVC
link.exe turns ICF on by default. As long as your program works
with default settings (or not passing /opt:noicf), your program
would work with LLD too.

llvm-svn: 240519
2015-06-24 04:36:52 +00:00
Peter Collingbourne c7b685d997 COFF: Ignore debug symbols.
Differential Revision: http://reviews.llvm.org/D10675

llvm-svn: 240487
2015-06-24 00:05:50 +00:00
Rui Ueyama 0d2e999050 COFF: Make link order compatible with MSVC link.exe.
Previously, we added files in directive sections to the symbol
table as we read the sections, so the link order was depth-first.
That's not compatible with MSVC link.exe nor the old LLD.

This patch is to queue files so that new files are added to the
end of the queue and processed last. Now addFile() doesn't parse
files nor resolve symbols. You need to call run() to process
queued files.

llvm-svn: 240483
2015-06-23 23:56:39 +00:00
Lang Hames 49047039b0 [lld] Add MachO thread-local storage support.
This allows LLD to correctly link MachO objects that use thread-local storage.

Differential Revision: http://reviews.llvm.org/D10578

llvm-svn: 240454
2015-06-23 20:35:31 +00:00
Simon Atanasyan 356d7c52b6 [Mips] Support R_MICROMIPS_HI0_LO16 relocation handling
llvm-svn: 240268
2015-06-22 09:27:05 +00:00
Simon Atanasyan f44f854af3 [Mips] Support R_MICROMIPS_LITERAL relocation handling
llvm-svn: 240267
2015-06-22 09:26:57 +00:00
Simon Atanasyan 692e792575 [Mips] Support R_MIPS_LITERAL relocation handling
llvm-svn: 240266
2015-06-22 09:26:48 +00:00
Simon Atanasyan ca0fe2f4a4 [Mips] Support R_MICROMIPS_SUB relocation handling
llvm-svn: 240265
2015-06-22 09:26:41 +00:00
Simon Atanasyan 1af72b898c [Mips] Reject R_MIPS_GPREL32 against external symbols
llvm-svn: 240264
2015-06-22 09:26:33 +00:00
Simon Atanasyan 74a07c5457 [Mips] Fix test case - do not use R_MIPS_GPREL32 against external symbols
No functional changes.

llvm-svn: 240263
2015-06-22 09:26:25 +00:00
Simon Atanasyan b5d26b1433 [Mips] Reject position-dependent relocations in case of shared library linking
llvm-svn: 240262
2015-06-22 09:26:20 +00:00
Simon Atanasyan 7851f3b111 [Mips] Fix test case - do not use R_MIPS_HI16 for shared library linking
No functional changes.

llvm-svn: 240261
2015-06-22 09:26:12 +00:00
Simon Atanasyan 46d97f246b [Mips] Support R_MICROMIPS_HIGHER / R_MICROMIPS_HIGHEST relocations handling
llvm-svn: 240260
2015-06-22 09:26:05 +00:00
Simon Atanasyan e55110454d [Mips] Support R_MIPS_HIGHER / R_MIPS_HIGHEST relocations handling
llvm-svn: 240259
2015-06-22 09:25:57 +00:00
Rui Ueyama a77336bd5d COFF: Support delay-load import tables.
DLLs are usually resolved at process startup, but you can
delay-load them by passing /delayload option to the linker.

If a /delayload is specified, the linker has to create data
which is similar to regular import table.
One notable difference is that the pointers in a delay-load
import table are originally pointing to thunks that resolves
themselves. Each thunk loads a DLL, resolve its name, and then
overwrites the pointer with the result so that subsequent
function calls directly call a desired function. The linker
has to emit thunks.

llvm-svn: 240250
2015-06-21 22:31:52 +00:00
Rui Ueyama 4d769c3a57 COFF: Support exception table.
.pdata section contains a list of triplets of function start address,
function end address and its unwind information. Linkers have to
sort section contents by function start address and set the section
address to the file header (so that runtime is able to find it and
do binary search.)

This change seems to resolve all but one remaining test failures in
check{,-clang,-lld} when building the entire stuff with clang-cl and
lld-link.

llvm-svn: 240231
2015-06-21 04:00:54 +00:00
Rui Ueyama 5e31d0b2e9 COFF: Fix common symbol alignment.
llvm-svn: 240217
2015-06-20 07:25:45 +00:00
Rui Ueyama efb7e1aa29 COFF: Fix a common symbol bug.
This is a case that one mistake caused a very mysterious bug.
I made a mistake to calculate addresses of common symbols, so
each common symbol pointed not to the beginning of its location
but to the end of its location. (Ouch!)

Common symbols are aligned on 16 byte boundaries. If a common
symbol is small enough to fit between the end of its real
location and whatever comes next, this bug didn't cause any harm.

However, if a common symbol is larger than that, its memory
naturally overlapped with other symbols. That means some
uninitialized variables accidentally shared memory. Because
totally unrelated memory writes mutated other varaibles, it was
hard to debug.

It's surprising that LLD was able to link itself and all LLD
tests except gunit tests passed with this nasty bug.

With this fix, the new COFF linker is able to pass all tests
for LLVM, Clang and LLD if I use MSVC cl.exe as a compiler.
Only three tests are failing when used with clang-cl.

llvm-svn: 240216
2015-06-20 07:21:57 +00:00
Rui Ueyama f00df0af2d COFF: Fix precedence between LIB and /libpath.
/libpath should take precedence over LIB.
Previously, LIB took precedence over /libpath.

llvm-svn: 240182
2015-06-19 22:39:48 +00:00
Rui Ueyama 165b254e06 COFF: Add search paths in the correct order.
Previously, we added search paths in reverse order.

llvm-svn: 240180
2015-06-19 21:44:32 +00:00
Rui Ueyama 573bf7de9c COFF: Continue reading object files until converge.
In this linker model, adding an undefined symbol may trigger chain
reactions. It may trigger a Lazy symbol to read a new file.
A new file may contain a directive section, which may contain various
command line options.

Previously, we didn't handle chain reactions well. We visited /include'd
symbols only once, so newly-added /include symbols were ignored.
This patch fixes that bug.

Now, the symbol table is versioned; every time the symbol table is
updated, the version number is incremented. We repeat adding undefined
symbols until the version number does not change. It is guaranteed to
converge -- the number of undefined symbol in the system is finite,
and adding the same undefined symbol more than once is basically no-op.

llvm-svn: 240177
2015-06-19 21:12:48 +00:00
Rui Ueyama 4d2834bd7b COFF: Don't add new undefined symbols for /alternatename.
Alternatename option is in the form of /alternatename:<from>=<to>.
It's effect is to resolve <from> as <to> if <from> is still undefined
at end of name resolution.

If <from> is not undefined but completely a new symbol, alternatename
shouldn't do anything. Previously, it introduced a new undefined
symbol for <from>, which resulted in undefined symbol error.

llvm-svn: 240161
2015-06-19 19:23:43 +00:00
Rui Ueyama 08d5e1875f COFF: Handle /include in .drectve.
We don't want to insert a new symbol to the symbol table while reading
a .drectve section because it's going to be too complicated.
That we are reading a directive section means that we are currently
reading some object file. Adding a new undefined symbol to the symbol
table can trigger a library file to read a new file, so it would make
the call stack too deep.

In this patch, I add new symbol names to a list to resolve them later.

llvm-svn: 240076
2015-06-18 23:20:11 +00:00
Rui Ueyama e8d56b5258 COFF: Allow identical alternatename options.
Alternatename option is in the form of /alternatename:<from>=<to>.
It is an error if there are two options having the same <from> but
different <to>. It is *not* an error if both are the same.

llvm-svn: 240075
2015-06-18 23:04:26 +00:00
Rui Ueyama 562daa8148 COFF: Unknown options in .drectve section is an error.
We skip unknown options in the command line with a warning message
being printed out, but we shouldn't do that for .drectve section.
The section is not visible to the user. We should handle unknown
options as an error.

llvm-svn: 240067
2015-06-18 21:50:38 +00:00
Rui Ueyama b95188cb2c COFF: Add /implib option.
llvm-svn: 240045
2015-06-18 20:27:09 +00:00
Rui Ueyama 2edb35a264 COFF: Handle /alternatename in .drectve section.
llvm-svn: 240037
2015-06-18 19:09:30 +00:00
Peter Collingbourne 8b2492f2a0 COFF: Implement DLL symbol exports for bitcode files.
Differential Revision: http://reviews.llvm.org/D10530

llvm-svn: 239994
2015-06-18 05:22:15 +00:00
Rui Ueyama ae36985af7 COFF: Fix entry point inference bug.
Previously, LLD couldn't find a default entry point if it's
defined by a library.

llvm-svn: 239982
2015-06-18 00:40:33 +00:00
Rui Ueyama 24c5fd0419 COFF: Support /manifest{,uac,dependency,file} options.
The linker has to create an XML file for each executable.
This patch supports that feature.

You can optionally embed an XML file to an executable as .rsrc
section. If you choose to do that (by passing /manifest:embed
option), the linker has to create a textual resource file
containing an XML file, compile that using rc.exe to a binary
resource file, conver that resource file to a COFF file using
cvtres.exe, and then link that COFF file. This patch implements
that feature too.

llvm-svn: 239978
2015-06-18 00:12:42 +00:00
Simon Atanasyan faf558224d [Mips] Use new llvm-readobj -mips-reginfo flag to check .reginfo content
No functional changes.

llvm-svn: 239962
2015-06-17 22:28:38 +00:00
Simon Atanasyan f8b082a6aa [Mips] Support R_MICROMIPS_GPREL16 / R_MICROMIPS_GPREL7_S2 relocations handling
llvm-svn: 239960
2015-06-17 22:27:54 +00:00
Simon Atanasyan 17478c5804 [Mips] Support R_MIPS_16 relocation handling
llvm-svn: 239959
2015-06-17 22:27:39 +00:00
Rui Ueyama 151d862d97 COFF: Create import library files.
On Windows, we have to create a .lib file for each .dll.
When linking against DLLs, the linker doesn't use the DLL files,
but instead read a list of dllexported symbols from corresponding
lib files.

A library file containing descriptors of a DLL is called an
import library file.

lib.exe has a feature to create an import library file from a
module-definition file. In this patch, we create a module-definition
file and pass that to lib.exe.

We eventually want to create an import library file by ourselves
to eliminate dependency to lib.exe. For now, we just use the MSVC
tool.

llvm-svn: 239937
2015-06-17 20:40:43 +00:00
Rui Ueyama 39026589b9 COFF: Fix a test which was failing with debug build.
llvm-svn: 239931
2015-06-17 19:28:01 +00:00
Rui Ueyama 1f373704e3 COFF: Support module-definition files.
Module-definition files (.def files) are yet another way to
specify parameters to the linker. You can write a list of dllexported
symbols in module-definition files instead of using /export command
line option. It also supports a few more directives.

The parser code is taken from lib/Driver/WinLinkModuleDef.cpp
with the following modifications.

 - variable names are updated to comply with the LLVM coding style.
 - Instead of returning parsing results as "directive" objects,
   it updates Config object directly.

llvm-svn: 239929
2015-06-17 19:19:25 +00:00
Adhemerval Zanella b19f5cfee6 [ELF/x86_64] Fix initial-exec TLS access
Current approach for initial-exec in ELF/x86_64 is to create a GOT entry
and change the relocation to R_X86_64_PC32 to be handled as a GOT offfset.
However there are two issues with this approach: 1. the R_X86_64_PC32 is
not really required since the GOT relocation will be handle dynamically and
2. the TLS symbols are not being exported externally and then correct
realocation are not being applied.

This patch fixes the R_X86_64_GOTTPOFF handling by just emitting a
R_X86_64_TPOFF64 dynamically one; it also sets R_X86_64_TPOFF64 to be
handled by runtime one.  For second part, the patches uses a similar
strategy used for aarch64, by reimplementing buildDynamicSymbolTable
from X86_64ExecutableWriter and adding the TLS symbols in the dynamic
symbol table.

Some tests had to be adjusted due the now missing R_X86_64_PC32 relocation.
With this test the simple testcase:

* t1.c:

__thread int t0;
__thread int t1;
__thread int t2;
__thread int t3;

* t0.c:

extern __thread int t0;
extern __thread int t1;
extern __thread int t2;
extern __thread int t3;

__thread int t4;
__thread int t5;
__thread int t6;
__thread int t7;

int main ()
{
  t0 = 1;
  t1 = 2;
  t2 = 3;
  t3 = 4;

  t4 = 5;
  t5 = 6;
  t6 = 7;
  t7 = 8;

  printf ("%i %i %i %i\n", t0, t1, t2, t3);
  printf ("%i %i %i %i\n", t4, t5, t6, t7);

  return 0;
}

Shows correct output for x86_64.

llvm-svn: 239908
2015-06-17 14:00:12 +00:00
Adhemerval Zanella 9c5831f3de [ELF] Fix wrong TBSS size
This patch fixes the wrong .tbss segment size generated for cases where
multiple modules have non initialized threads variables.  For instance:

* t0.c

__thread int x0;
__thread int x1;
__thread int x2;

extern __thread int e0;
extern __thread int e1;
extern __thread int e2;
extern __thread int e3;

int foo0 ()
{
  return x0;
}

int main ()
{
  return x0;
}

* t1.c

__thread int e0;
__thread int e1;
__thread int e2;
__thread int e3;


lld is generating (for aarch64):

  [14] .tbss             NOBITS           0000000000401000  00001000
       0000000000000010  0000000000000000 WAT       0     0     4

Where is just taking in consideration the largest tbss segment, not all
from all objects.  ld generates a correct output:

  [17] .tbss             NOBITS           0000000000410dec  00000dec
       000000000000001c  0000000000000000 WAT       0     0     4

This issue is at 'lib/ReaderWriter/ELF/SegmentChunks.cpp' where
Segment<ELFT>::assignVirtualAddress is setting wrong slice values, not taking care
of although tbss segments file size does noy play role in other segment virtual
address placement, its size should still be considered.

llvm-svn: 239906
2015-06-17 13:46:07 +00:00