Right now we just remember a SymbolBody for each got entry and
duplicate a bit of logic to decide what value, if any, should be
written for that SymbolBody.

With ARM there will be more complicated values, and it seems better to
just use the relocation code to fill the got entries. This makes it
clear that each entry is filled by the dynamic linker or by the static
linker.

llvm-svn: 288107

llvm-svn: 288102

That unifies handling cases when we have SECTIONS and when
-no-rosegment is given in compareSectionsNonScript()

Now Config->SingleRoRx is used for check, testcase is provided.

llvm-svn: 288022

Previously Config->SingleRoRx was set in
createFiles() and used HasSections.

This change moves it to readConfigs at place of
common flags handling, and adds logic that sets
this flag separatelly from ScriptParser if SECTIONS present.

llvm-svn: 288021

--no-rosegment: Do not put read-only non-executable sections in their own segment

Differential revision: https://reviews.llvm.org/D26889

llvm-svn: 288020

Differential revision: https://reviews.llvm.org/D27108

llvm-svn: 288019

Unfortunatelly PT_ARM_EXIDX is special. There is no way to create it
from linker scripts, so we have to create it even if PHDRS is used.

This matches bfd and is required for the lld output to survive bfd's strip.

llvm-svn: 288012

When we iterate over numbers as opposed to iterable elements,
parallel_for fits better than parallel_for_each.

llvm-svn: 288002

Unfortunatelly some scripts look like

kernphys = ...
. = ....

and the expectation in that every orphan section is after the
assignment.

llvm-svn: 287996

This is an horrible special case, but seems to match bfd's behaviour
and is important for avoiding placing an orphan section before the
expected start of the file.

llvm-svn: 287994

They return new vectors, but at the same time they mutate other vectors,
so returning values doesn't make much sense. We should just mutate two
vectors.

llvm-svn: 287979

Config->ColorDiagnostics was of type enum before. Now it is just a
boolean flag. Thanks Rafael for suggestion.

llvm-svn: 287978

llvm-svn: 287977

This matches the behaviour of bfd ld. Using 0 was causing problems
with strip, which would remove these sections.

llvm-svn: 287969

llvm-svn: 287967

llvm-svn: 287951

llvm-svn: 287950

-color-diagnostics=auto is default because that's the same as
Clang's default. When color is enabled, error or warning messages
are colored like this.

  error:
  <bold>ld.lld</bold> <red>error:</red> foo.o: no such file

  warning:
  <bold>ld.lld</bold> <magenta>warning:</magenta> foo.o: no such file

Differential Revision: https://reviews.llvm.org/D27117

llvm-svn: 287949

llvm-svn: 287948

Uncompressing section contents and spliting mergeable section contents
into smaller chunks are heavy tasks. They scan entire section contents
and do CPU-intensive tasks such as uncompressing zlib-compressed data
or computing a hash value for each section piece.

Luckily, these tasks are independent to each other, so we can do that
in parallel_for_each. The number of input sections is large (as opposed
to the number of output sections), so there's a large parallelism here.

Actually the current design to call uncompress() and splitIntoPieces()
in batch was chosen with doing this in mind. Basically what we need to
do here is to replace `for` with `parallel_for_each`.

It seems this patch improves latency significantly if linked programs
contain debug info (which in turn contain lots of mergeable strings.)
For example, the latency to link Clang (debug build) improved by 20% on
my machine as shown below. Note that ld.gold took 19.2 seconds to do
the same thing.

Before:
    30801.782712 task-clock (msec)         #    3.652 CPUs utilized            ( +-  2.59% )
         104,084 context-switches          #    0.003 M/sec                    ( +-  1.02% )
           5,063 cpu-migrations            #    0.164 K/sec                    ( +- 13.66% )
       2,528,130 page-faults               #    0.082 M/sec                    ( +-  0.47% )
  85,317,809,130 cycles                    #    2.770 GHz                      ( +-  2.62% )
  67,352,463,373 stalled-cycles-frontend   #   78.94% frontend cycles idle     ( +-  3.06% )
 <not supported> stalled-cycles-backend
  44,295,945,493 instructions              #    0.52  insns per cycle
                                           #    1.52  stalled cycles per insn  ( +-  0.44% )
   8,572,384,877 branches                  #  278.308 M/sec                    ( +-  0.66% )
     141,806,726 branch-misses             #    1.65% of all branches          ( +-  0.13% )

     8.433424003 seconds time elapsed                                          ( +-  1.20% )

After:
    35523.764575 task-clock (msec)         #    5.265 CPUs utilized            ( +-  2.67% )
         159,107 context-switches          #    0.004 M/sec                    ( +-  0.48% )
           8,123 cpu-migrations            #    0.229 K/sec                    ( +- 23.34% )
       2,372,483 page-faults               #    0.067 M/sec                    ( +-  0.36% )
  98,395,342,152 cycles                    #    2.770 GHz                      ( +-  2.62% )
  79,294,670,125 stalled-cycles-frontend   #   80.59% frontend cycles idle     ( +-  3.03% )
 <not supported> stalled-cycles-backend
  46,274,151,813 instructions              #    0.47  insns per cycle
                                           #    1.71  stalled cycles per insn  ( +-  0.47% )
   8,987,621,670 branches                  #  253.003 M/sec                    ( +-  0.60% )
     148,900,624 branch-misses             #    1.66% of all branches          ( +-  0.27% )

     6.747548004 seconds time elapsed                                          ( +-  0.40% )

llvm-svn: 287946

llvm-svn: 287945

llvm-svn: 287944

The function was used only within Relocations.cpp, but now we are
using it in many places, so this patch moves it to a file that fits
to the functionality.

llvm-svn: 287943

llvm-svn: 287938

Differential revision: https://reviews.llvm.org/D27055

llvm-svn: 287915

Differential revision: https://reviews.llvm.org/D27098

llvm-svn: 287914

This is important for cases like:

  .sdata        : {
    *(.got.plt .got)
...
  }

That was not supported before as there was no way to get access to 
synthetic sections from script.

More details on review page.

Differential revision: https://reviews.llvm.org/D27040

llvm-svn: 287913

llvm-svn: 287901

This patch changes the error message from

  too many errors emitted, stopping now

to

  too many errors emitted, stopping now (use -error-limit=0 to see all errors)

Thanks for Sean for the suggestion!

llvm-svn: 287900

Differential Revision: https://reviews.llvm.org/D27065

llvm-svn: 287899

llvm-svn: 287895

    
The .ARM.exidx table has an entry for each function with the first entry
giving the start address of the function, the table is sorted in ascending
order of function address. Given a PC value, the unwinder will search the
table for the entry that contains the PC value.
    
If the table entry happens to be the last, the range of the addresses that
the final unwinding table describes will extend to the end of the address
space. To prevent an incorrect address outside the address range of the
program matching the last entry we follow ld.bfd's example and add a
sentinel EXIDX_CANTUNWIND entry at the end of the table. This gives the
final real table entry an upper bound.
    
In addition the llvm libunwind unwinder currently depends on the presence
of a sentinel entry (PR31091).

Differential revision: https://reviews.llvm.org/D26977

llvm-svn: 287869

llvm-svn: 287860

llvm-svn: 287850

HasError was always true if ErrorCount > 0, so we can use ErrorCount instead.

llvm-svn: 287849

Previously, if a symbol specified by -e or ENTRY() is not found,
we didn't set entry point address. That is incompatible with GNU
because GNU linkers set the first address of .text to entry.
This patch implement that behavior.

llvm-svn: 287836

Offset between beginning of a .got section and _gp symbols used in MIPS
GOT relocations calculations. Usually the expression looks like
VA + Offset - GP, where VA is the .got section address, Offset - offset
of the GOT entry, GP - offset between .got and _gp. Also there two "magic"
symbols _gp_disp and __gnu_local_gp which hold the offset mentioned above.
These symbols might be referenced by MIPS relocations.

Now the linker always defines _gp symbol and uses hardcoded value for
its initialization. So offset between .got and _gp is 0x7ff0. The _gp_disp
and __gnu_local_gp defined if required and initialized by 0x7ff0.
In fact that is not correct because _gp symbol might be defined by a linker
script and holds arbitrary value. In that case we need to use this value
in relocation calculation and initialize _gp_disp and __gnu_local_gp
properly.

The patch fixes the problem and completes fixing the bug #30311.
https://llvm.org/bugs/show_bug.cgi?id=30311

Differential revision: https://reviews.llvm.org/D27036

llvm-svn: 287832

llvm-svn: 287830

They are essentially the same in this context, so I prefer the one
that doesn't need `Twine::`.

llvm-svn: 287814

Looks like we have no 32 bit bot that builds with mips support.

llvm-svn: 287799