Commit Graph

4350 Commits

Author SHA1 Message Date
Peter Collingbourne 9106b2becd Use /pdbaltpath to avoid a path length dependency.
llvm-svn: 330485
2018-04-20 21:54:55 +00:00
Peter Collingbourne 3d636edc56 COFF: Merge .xdata into .rdata by default.
Differential Revision: https://reviews.llvm.org/D45804

llvm-svn: 330484
2018-04-20 21:32:37 +00:00
Peter Collingbourne 326f419335 COFF: Merge .bss into .data by default.
Differential Revision: https://reviews.llvm.org/D45803

llvm-svn: 330483
2018-04-20 21:30:36 +00:00
Rui Ueyama 88fe5c9557 Add -z {combreloc,copyreloc,noexecstack,lazy,relro,text}.
Differential Revision: https://reviews.llvm.org/D45902

llvm-svn: 330482
2018-04-20 21:24:08 +00:00
Peter Collingbourne 71c7de5b77 COFF: Preserve section type when processing /section flag.
It turns out that we were dropping this before.

Differential Revision: https://reviews.llvm.org/D45802

llvm-svn: 330481
2018-04-20 21:23:16 +00:00
Peter Collingbourne 381b3d8aa3 COFF: Use (name, output characteristics) as a key when grouping input sections into output sections.
This is what link.exe does and lets us avoid needing to worry about
merging output characteristics while adding input sections to output
sections.

With this change we can't process /merge in the same way as before
because sections with different output characteristics can still
be merged into one another. So this change moves the processing of
/merge to just before we assign addresses. In the case where there
are multiple output sections with the same name, link.exe only merges
the first section with the source name into the first section with
the target name, and we do the same.

At the same time I also implemented transitive merging (which means
that /merge:.c=.b /merge:.b=.a merges both .c and .b into .a).

This isn't quite enough though because link.exe has a special case for
.CRT in 32-bit mode: it processes sections whose output characteristics
are DATA | R | W as though the output characteristics were DATA | R
(so that they get merged into things like constructor lists in the
expected way). Chromium has a few such sections, and it turns out
that those sections were causing the problem that resulted in r318699
(merge .xdata into .rdata) being reverted: because of the previous
permission merging semantics, the .CRT sections were causing the entire
.rdata section to become writable, which caused the SEH runtime to
crash because it apparently requires .xdata to be read-only. This
change also implements the same special case.

This should unblock being able to merge .xdata into .rdata by default,
as well as .bss into .data, both of which will be done in followups.

Differential Revision: https://reviews.llvm.org/D45801

llvm-svn: 330479
2018-04-20 21:10:33 +00:00
Sterling Augustine 7026d3bac4 Under some scenarios, the current directory isn't writable
during a test. Set the output path to avoid that problem.

llvm-svn: 330464
2018-04-20 18:45:24 +00:00
Zachary Turner 194be871b9 [LLD/PDB] Emit first section contribution for DBI Module Descriptor.
Part of the DBI stream is a list of variable length structures
describing each module that contributes to the final executable.

One member of this structure is a section contribution entry that
describes the first section contribution in the output file for
the given module.

We have been leaving this structure unpopulated until now, so with
this patch it is now filled out correctly.

Differential Revision: https://reviews.llvm.org/D45832

llvm-svn: 330457
2018-04-20 18:00:46 +00:00
Nicholas Wilson 358af38d37 [WebAssembly] Implement -print-gc-sections, to better test GC of globals
Differential Revision: https://reviews.llvm.org/D44311

llvm-svn: 330456
2018-04-20 17:28:12 +00:00
Nicholas Wilson a1e299f58b [WebAssembly] Implement GC for imports
Differential Revision: https://reviews.llvm.org/D44313

llvm-svn: 330454
2018-04-20 17:18:06 +00:00
Nicholas Wilson 6c7fe30a1c [WebAssembly] Implement --print-gc-sections for synthetic functions
Enables cleaning up confusion between which name variables are mangled
and which are unmangled, and --print-gc-sections then excersises and
tests that.

Differential Revision: https://reviews.llvm.org/D44440

llvm-svn: 330449
2018-04-20 17:09:18 +00:00
Fangrui Song 2416d7fcb2 [ELF] --warn-backrefs: use the same GroupId for object files in the same --{start,end}-lib
Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D45849

llvm-svn: 330443
2018-04-20 16:33:01 +00:00
Rafael Espindola a59aacf52b Fix trap instruction on pp64.
The test was passing on a big endian host, but just because od with x4
was compensating for it.

llvm-svn: 330386
2018-04-20 01:21:24 +00:00
Fangrui Song b72daf00f4 [ELF] Increase NextGroupId with --end-group
Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D45846

llvm-svn: 330379
2018-04-19 23:23:23 +00:00
Sam Clegg 0dbe57e752 [WebAssembly] Fix bug where reloc addends were written as unsigned
Relocation addends can be negative so should be written as
signed LEBs. This bug meant that writing value between 64
and 128 would be incorrectly interpreted as negative by the
object file readers.

Differential Revision: https://reviews.llvm.org/D45825

llvm-svn: 330374
2018-04-19 22:48:03 +00:00
Rafael Espindola 991c1cd5f7 Add a test. NFC.
We have relatively few tests on the contents of non alloc
sections. This one would have found a bug in a patch I am working on.

llvm-svn: 330369
2018-04-19 21:58:28 +00:00
Reid Kleckner 8f1a28f190 [COFF] Mark images with no exception handlers for /safeseh
Summary:
DLLs and executables with no exception handlers need to be marked with
IMAGE_DLL_CHARACTERISTICS_NO_SEH, even if they have a load config.

Discovered here when building Chromium with LLD on Windows:
https://crbug.com/833951

Reviewers: ruiu, mstorsjo

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45778

llvm-svn: 330300
2018-04-18 22:37:10 +00:00
Peter Collingbourne 3108802f16 COFF: Friendlier undefined symbol errors.
Summary:
This change does three things:
- Try to find the file and line number of an undefined symbol
  reference by reading codeview debug info.
- Try to find the name of the function or global variable with the
  undefined symbol reference by searching the object file's symbol
  table.
- Prints the information in the same style as the ELF linker.

Differential Revision: https://reviews.llvm.org/D45467

llvm-svn: 330235
2018-04-17 23:32:33 +00:00
Michael J. Spencer b842725c1d [ELF] Add profile guided section layout
This adds profile guided layout using the Call-Chain Clustering (C³) heuristic
from https://research.fb.com/wp-content/uploads/2017/01/cgo2017-hfsort-final1.pdf .

RFC: [llvm-dev] [RFC] Profile guided section layout
     http://lists.llvm.org/pipermail/llvm-dev/2017-June/114178.html

Pass `--call-graph-ordering-file <file>` to read a call graph profile where each
line has the format:

    <from symbol> <to symbol> <call count>

Differential Revision: https://reviews.llvm.org/D36351

llvm-svn: 330234
2018-04-17 23:30:05 +00:00
Peter Collingbourne 66f1c9a858 Reland r330223, "COFF: Merge .idata, .didat and .edata into .rdata by default.", which was reverted in r330228.
In this reland I removed an unnecessary use of /debug in the test
delayimports32.test and used the /pdbaltpath flag in the test
pdb-publics-import.test, both of which avoid embedding absolute PDB
paths in executables which could affect later RVAs.

Original commit message:
> COFF: Merge .idata, .didat and .edata into .rdata by default.
>
> This saves a little space and matches what link.exe does.
>
> Tested using the chromium Windows trybots:
> https://chromium-review.googlesource.com/c/chromium/src/+/1014784

Differential Revision: https://reviews.llvm.org/D45737

llvm-svn: 330233
2018-04-17 23:28:52 +00:00
Peter Collingbourne 94aa62e48a COFF: Implement /pdbaltpath flag.
I needed to revert r330223 because we were embedding an absolute PDB
path in the .rdata section, which ended up being laid out before the
.idata section and affecting its RVAs. This flag will let us control
the embedded path.

Differential Revision: https://reviews.llvm.org/D45747

llvm-svn: 330232
2018-04-17 23:28:38 +00:00
Peter Collingbourne 1254f3e77c Revert r330223, "COFF: Merge .idata, .didat and .edata into .rdata by default."
Seems to have uncovered some sort of non-determinism on the bots.

llvm-svn: 330228
2018-04-17 22:16:39 +00:00
Peter Collingbourne 09e0e2e656 COFF: Merge .idata, .didat and .edata into .rdata by default.
This saves a little space and matches what link.exe does.

Tested using the chromium Windows trybots:
https://chromium-review.googlesource.com/c/chromium/src/+/1014784

Differential Revision: https://reviews.llvm.org/D45737

llvm-svn: 330223
2018-04-17 21:44:31 +00:00
Peter Collingbourne 7c26663f58 llvm-pdbutil: Fix an off-by-one error.
Differential Revision: https://reviews.llvm.org/D45740

llvm-svn: 330222
2018-04-17 21:44:17 +00:00
Zachary Turner bee6c22414 [llvm-pdbutil] Dump first section contribution for each module.
The DBI stream contains a list of module descriptors.  At the
beginning of each descriptor is a structure representing the first
section contribution in the output file for that module.  LLD
currently doesn't fill out this structure at all, but link.exe
does.  So as a precursor to emitting this data in LLD, we first
need a way to dump it so that it can be checked.

This patch adds support for the dumping, and verifies via a test
that LLD emits bogus information.

llvm-svn: 330208
2018-04-17 20:06:43 +00:00
Reid Kleckner 9c86a31307 Revert r329960 "Do not keep shared symbols created from garbage-collected eliminated DSOs."
This is causing large numbers of Chromium test executables to crash on
shutdown. The relevant symbol seems to be __cxa_finalize, which gets
removed from the dynamic symbol table for some of the support libraries.

llvm-svn: 330164
2018-04-16 22:45:23 +00:00
Zachary Turner e3fe669855 Resubmit "Fix some incorrect fields in our generated PDBs."
This fixes the failing tests.  They simply hadn't been updated
to match the new output resulting from this patch.

llvm-svn: 330145
2018-04-16 18:17:13 +00:00
Simon Atanasyan 1ba194212a [ELF][MIPS] Support linking of PIE for MIPS
MIPS ABI requires creation of the MIPS_RLD_MAP dynamic tag for non-PIE
executables only and MIPS_RLD_MAP_REL tag for both PIE and non-PIE
executables. The patch skips definition of the MIPS_RLD_MAP for PIE
files and defines MIPS_RLD_MAP_REL.

The MIPS_RLD_MAP_REL tag stores the offset to the .rld_map section
relative to the address of the tag itself.

Differential Revision: https://reviews.llvm.org/D43347

llvm-svn: 329996
2018-04-13 08:15:01 +00:00
Rui Ueyama 039d248778 Do not keep shared symbols created from garbage-collected eliminated DSOs.
If all references to a DSO happen to be weak, and if the DSO is
specified with --as-needed, the DSO is not added to DT_NEEDED.
If that happens, we also need to eliminate shared symbols created
from the DSO. Otherwise, they become dangling references that point
to non-exsitent DSO.

Fixes https://bugs.llvm.org/show_bug.cgi?id=36991

Differential Revision: https://reviews.llvm.org/D45536

llvm-svn: 329960
2018-04-12 21:57:04 +00:00
Sam Clegg 225c4697b4 [WebAssembly] Match llvm change to custom section size
Summary:
The content of custome sections no longer includes the
name itself.

See: https://reviews.llvm.org/D45579

Subscribers: jfb, dschuff, jgravelle-google, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D45580

llvm-svn: 329948
2018-04-12 20:31:35 +00:00
George Rimar c552619fc1 [ELF] - Reorder local symbols.
This fixes PR36716 (https://bugs.llvm.org/show_bug.cgi?id=36716),

Patch sorts local symbols to match the
following order: file1, local1, hidden1, file2, local2, hidden2 ...

Differential revision: https://reviews.llvm.org/D45325

llvm-svn: 329787
2018-04-11 09:24:27 +00:00
Rafael Espindola 262589db70 Don't warn on ICFed symbols, warn on synthetic ones.
Based on a patch for the ICF warning by Rui.

llvm-svn: 329757
2018-04-10 21:13:52 +00:00
Sam Clegg 80ba43872e [WebAssembly] Add support for custom sections
Copy user-defined custom sections into the output, concatenating
sections with the same name.

Differential Revision: https://reviews.llvm.org/D45340

llvm-svn: 329717
2018-04-10 16:12:49 +00:00
George Rimar e160473823 [ELF] - Do not crash when trying to order --defsym/linker script symbols.
Currently, we crash because File is null for
such symbols.

Differential revision: https://reviews.llvm.org/D45440

llvm-svn: 329678
2018-04-10 09:44:44 +00:00
Rui Ueyama e4ba9044ad Add a test for nested --start-group.
llvm-svn: 329642
2018-04-09 23:30:21 +00:00
Rui Ueyama 1d92aa7380 Add --warn-backrefs to maintain compatibility with other linkers
I'm proposing a new command line flag, --warn-backrefs in this patch.
The flag and the feature proposed below don't exist in GNU linkers
nor the current lld.

--warn-backrefs is an option to detect reverse or cyclic dependencies
between static archives, and it can be used to keep your program
compatible with GNU linkers after you switch to lld. I'll explain the
feature and why you may find it useful below.

lld's symbol resolution semantics is more relaxed than traditional
Unix linkers. Therefore,

  ld.lld foo.a bar.o

succeeds even if bar.o contains an undefined symbol that have to be
resolved by some object file in foo.a. Traditional Unix linkers
don't allow this kind of backward reference, as they visit each
file only once from left to right in the command line while
resolving all undefined symbol at the moment of visiting.

In the above case, since there's no undefined symbol when a linker
visits foo.a, no files are pulled out from foo.a, and because the
linker forgets about foo.a after visiting, it can't resolve
undefined symbols that could have been resolved otherwise.

That lld accepts more relaxed form means (besides it makes more
sense) that you can accidentally write a command line or a build
file that works only with lld, even if you have a plan to
distribute it to wider users who may be using GNU linkers.  With
--check-library-dependency, you can detect a library order that
doesn't work with other Unix linkers.

The option is also useful to detect cyclic dependencies between
static archives. Again, lld accepts

  ld.lld foo.a bar.a

even if foo.a and bar.a depend on each other. With --warn-backrefs
it is handled as an error.

Here is how the option works. We assign a group ID to each file. A
file with a smaller group ID can pull out object files from an
archive file with an equal or greater group ID. Otherwise, it is a
reverse dependency and an error.

A file outside --{start,end}-group gets a fresh ID when
instantiated. All files within the same --{start,end}-group get the
same group ID. E.g.

  ld.lld A B --start-group C D --end-group E

A and B form group 0, C, D and their member object files form group
1, and E forms group 2. I think that you can see how this group
assignment rule simulates the traditional linker's semantics.

Differential Revision: https://reviews.llvm.org/D45195

llvm-svn: 329636
2018-04-09 23:05:48 +00:00
Rumeet Dhindsa 682a417e51 Added support for LTO options: sample_profile, new_pass_manager and debug_pass_manager
Differential Revision: https://reviews.llvm.org/D45275

llvm-svn: 329598
2018-04-09 17:56:07 +00:00
George Rimar aeb7e305b8 [ELF] - Simplify test case. NFC.
llvm-svn: 329563
2018-04-09 13:13:36 +00:00
George Rimar 0029f21482 [ELF] - Stop setting OutSecOff too early.
Currently LLD sets OutSecOff in addSection for input sections.
That is a fake offset (just a rude approximation to remember the order), 
used for sorting SHF_LINK_ORDER sections
(see resolveShfLinkOrder, compareByFilePosition).

There are 2 problems with such approach:

1. We currently change and reuse Size field as a value assigned. Changing size is
not good because leads to bugs. Currently, SIZEOF(.bss) for empty .bss returns 2
because we add two empty synthetic sections and increase size twice by 1. 
(See PR37011: https://bugs.llvm.org/show_bug.cgi?id=37011)

2. Such approach simply does not work when --symbol-ordering-file is involved,
because processing of the ordering file might break the initial section order.

This fixes PR37011.

Differential revision: https://reviews.llvm.org/D45368

llvm-svn: 329560
2018-04-09 13:01:50 +00:00
George Rimar 9bc20fff4a [ELF] - Fix cref.s test case.
The intention of -gc-sections flag was to check
that discarded is not in the output. It should be
specified in the executable command line invocation
and also, the symbol must be global as local symbols
are anyways not printed.

Differential revision: https://reviews.llvm.org/D45159

llvm-svn: 329559
2018-04-09 12:45:29 +00:00
George Rimar 7bf92be676 [ELF] - Allow LLD to produce file symbols.
This is for PR36716 and
this enables emitting STT_FILE symbols.

Output size affect is minor:
lld binary size changes from 52,883,408 to 52,949,400
clang binary size changes from 83,136,456 to 83,219,600

Differential revision: https://reviews.llvm.org/D45261

llvm-svn: 329557
2018-04-09 11:43:52 +00:00
Aaron Smith c3b5515e51 [tests] Fix format-binary-non-ascii.s to work with Python 3 on Windows
Some platforms interpret the pound sign as one character. Platforms that use 
Python 2.x actually interpret it as two characters because in the Python 2.x 
version of lit, the string used for the file name is a byte string and the pound 
sign is two bytes.

Patch by Stella Stamenova!

llvm-svn: 329472
2018-04-07 00:55:26 +00:00
Peter Collingbourne 4902508934 COFF: Process /merge flag as we create output sections.
With this we can merge builtin sections.

Differential Revision: https://reviews.llvm.org/D45350

llvm-svn: 329471
2018-04-07 00:46:55 +00:00
Benjamin Kramer d726d04f45 [ELF] Don't write to the source directory in test.
llvm-svn: 329384
2018-04-06 10:05:47 +00:00
Rafael Espindola 3bd98b1031 Change which file we print when a symbol cannot be ordered.
Currently there are a few odd things about the warning about symbols
that cannot be ordered. This patch fixes:

* When there is an undefined symbol that resolves to a shared file, we
  were printing the location of the undefined reference.

* If there are multiple comdats, we were reporting them all.

llvm-svn: 329371
2018-04-06 03:36:19 +00:00
Rafael Espindola 9b6a65b144 Don't ignore addend when a SHF_MERGE section is dead.
This is similar to r329219, but for the entire section. Like r329219 I
don't expect this to have any real impact, it is just more consistent
and simpler.

llvm-svn: 329367
2018-04-06 01:10:33 +00:00
Fangrui Song c43eff6208 [ELF] Add CHECK to test/ELF/undef-start.s
llvm-svn: 329333
2018-04-05 19:20:33 +00:00
Rui Ueyama 4e150c4c88 Make "Size" column in the map file one characters shorter.
Previously, "size" column is 9 characters long which is too long
at least for 32-bit (because at maximum it needs 8 columns). This
patch make it one column shorter than before. That's also a reasonable
default for 64-bit.

llvm-svn: 329317
2018-04-05 17:20:18 +00:00
Rui Ueyama 16a130bc78 Fix column size in the map file.
Size can be narrow, but LMA should be the same width as VMA.

llvm-svn: 329312
2018-04-05 16:45:37 +00:00
Rafael Espindola 5f8e77afb5 Initialize OutputOff to zero.
We have a dedicated Live bit, so we don't need a special value and we
were not accounting for in at least one place.

llvm-svn: 329307
2018-04-05 15:56:04 +00:00