LLD supports multi-threading, and it seems to be working well as
you can see in r287140. In short, LLD runs a few percent to 30%
faster with -threads and more than 50% faster if you are using
-build-id (your mileage may vary depending on your computer).

However, I don't think most users even don't know about that because
-threads is not a default option.

This patch enables it by default.

Discussion thread:
http://lists.llvm.org/pipermail/llvm-dev/2016-November/107160.html

llvm-svn: 287237

Our build-id is a tree hash anyway, so I'll define this as a synonym
for sha1. GNU gold takes this parameter, so this is for compatibility
with that.

llvm-svn: 287119

llvm-svn: 287072

The functions getBitcodeTargetTriple(), isBitcodeContainingObjCCategory(),
getBitcodeProducerString() and hasGlobalValueSummary() now return errors
via their return value rather than via the diagnostic handler.

To make this work, re-implement these functions using non-member functions
so that they can be used without the LLVMContext required by BitcodeReader.

Differential Revision: https://reviews.llvm.org/D26532

llvm-svn: 286623

This is forcing to use Error::success(), which is in a wide majority
of cases a lot more readable.

Differential Revision: https://reviews.llvm.org/D26481

llvm-svn: 286561

The previous code didn't make sense at all. Now an error condition
is handled with fatal(). Thanks to Mehdi for pointing out the issue.

llvm-svn: 286547

Patch allows to pass a symbols file to linker.
LLD will map symbols to sections and sort sections
in output according to symbol ordering file.

That can help to reduce the startup time and/or
amount of pagefaults during startup.

Also, interesting benchmark result was produced by Rafael Espíndola. 
After applying the symbols file for clang he timed compiling 
X86MCTargetDesc.ii to an object file.  

The page faults went from just
56,988 to 56,946 since most faults are not in the binary.
Running time went from 4.403053515 to 4.178112244. 
The speedup seems to be because of better cache
locality.

Differential revision: https://reviews.llvm.org/D26130

llvm-svn: 286440

llvm-svn: 286406

Avoids having to skip them multiple times.

llvm-svn: 286261

In short the patch introduces support for linking object file conform
MIPS N32 ABI [1]. This ABI is similar to N64 ABI but uses 32-bit
pointer size.

The most non-trivial requirement of this ABI is one more relocation
packing format. N64 ABI puts multiple relocation type into the single
relocation record. The N32 ABI uses series of successive relocations
with the same offset for this purpose. In this patch, new function
`mergeMipsN32RelTypes` handle this case and "convert" N32 relocation to
the N64 relocation so the rest of the code keep unchanged.

For now, linker does not support series of relocations applied to sections
without SHF_ALLOC bit. Probably later I will add the support or insert
some sort of assert into the `relocateNonAlloc` routine to catch this
case.

[1] ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/MIPS-N32-ABI-Handbook.pdf

Differential revision: https://reviews.llvm.org/D26298

llvm-svn: 286052

Previously, we do this piece of code to iterate over all input sections.

  for (elf::ObjectFile<ELFT> *F : Symtab.getObjectFiles())
    for (InputSectionBase<ELFT> *S : F->getSections())

It turned out that this mechanisms doesn't work well with synthetic
input sections because synthetic input sections don't belong to any
input file.

This patch defines a vector that contains all input sections including
synthetic ones.

llvm-svn: 286051

You can now write make<T>(Args) instead of new (alloc<T>()) T(Args).

llvm-svn: 285760

This patch replaces GAlloc<ELFT>::<sometype>.Allocate() with
alloc<sometype<ELFT>>().

Patch by Rui!

llvm-svn: 285748

Previously, we have a lot of BumpPtrAllocators, but all these
allocators virtually have the same lifetime because they are
not freed until the linker finishes its job. This patch aggregates
them into a single allocator.

Differential revision: https://reviews.llvm.org/D26042

llvm-svn: 285452

This allows us to set a value for it based on -m.

llvm-svn: 285294

As the state of lld gets more complicated, shutting down gets more
expensive.

In a normal lld run we can just call _exit immediately after renaming
the temporary output file. We still want the ability to run a full
shutdown since that is useful for detecting memory leaks.

This patch adds a --full-shutdown flag and changes lit to use it.

llvm-svn: 285224

We used to have one allocator per file, which reduces the advantage of
using an allocator in the first place.

This is a small speed up is most cases. The largest speedup was in
1.014X in chromium no-gc. The largest slowdown was scylla at 1.003X.

llvm-svn: 285205

llvm-svn: 285169

llvm-svn: 285164

This is in sync with what clang does.

llvm-svn: 285163

In this patch partial gdb_index section is created. 
For costructing the .gdb_index section 6 steps should be performed (details are in
SplitDebugInfo.cpp file header), this patch do first 3:

Creates proper section header.
Fills list of compilation units.
Types CU list area is not supposed to be supported, so it is ignored and therefore
can be treated as implemented either.

Differential revision: https://reviews.llvm.org/D24706

llvm-svn: 284708

llvm-svn: 284705

llvm-svn: 284697

This member is used only by LinkerDriver, so move it to LinkerDriver.

llvm-svn: 284696

llvm-svn: 284695

llvm-svn: 284694

-format=<foo>, -format <foo> and -b <foo> are all the same.
Previous code was intended to produce an error message with the
same spelling as given from the command line, but it actually
always printed out this string: "unknown -format= value:".
This is probably more confusing than "unknown -format value:".
So I changed the message.

llvm-svn: 284693

llvm-svn: 284692

Previously, we were checking the existence of an entry symbol
too early. It was done before the linker script processor creates
symbols defined in scripts. Fixes bug 30743.

llvm-svn: 284676

llvm-svn: 284641

This is what other linkers and clang driver do.

Differential Revision: https://reviews.llvm.org/D25780

llvm-svn: 284634

Other error messages don't end with ".".

llvm-svn: 284625

The R_ARM_TARGET2 relocation is used in ARM exception tables to encode
a data dependency that will only be dereferenced by code in the
run-time support library. In a similar way to R_ARM_TARGET1 the
handling of the relocation is target specific, it maps to one of
R_ARM_ABS32, R_ARM_REL32 or R_ARM_GOT_PREL. The choice depends on the 
run-time library. R_ARM_GOT_PREL is used for linux and BSD,
R_ARM_ABS32 and R_ARM_REL32 are used for bare-metal.

The command line option --target2=<target> can be used to select the
relocation used for R_ARM_TARGET2. The default is R_ARM_GOT_PREL.

Differential revision: https://reviews.llvm.org/D25684

llvm-svn: 284404

This is https://llvm.org/bugs/show_bug.cgi?id=30696,

Differential revision: https://reviews.llvm.org/D25676

llvm-svn: 284388

-z wxneeded creates a PHDR PT_OPENBSD_WXNEEDED.

PT_OPENBSD_WXNEEDED
The array element specifies that a process executing this file may need to be able to map or protect memory regions as simultaneously executable and writable. If the system is unable or unwilling to permit that for this executable then it may fail immediately. This segment type is meaningful only for executable files and is ignored in other objects.

http://man.openbsd.org/OpenBSD-current/man5/elf.5

Differential revision: https://reviews.llvm.org/D25472

llvm-svn: 284226

llvm-svn: 283910

Differential Revision:   https://reviews.llvm.org/D25452

llvm-svn: 283817

llvm-svn: 282964

It's better because it's a verb.

llvm-svn: 282763

This options issupported by both BFD ld and gold and allows
overriding the max page size whose default values are defined by
the target.

https://llvm.org/bugs/show_bug.cgi?id=30541

Differential Revision: https://reviews.llvm.org/D24891

llvm-svn: 282596