This change continues what was started by D27040
Now all allocatable synthetics should be available from script side.
Differential revision: https://reviews.llvm.org/D27131
llvm-svn: 288150
The MipsGotSection::getPageEntryOffset calculates index of GOT entry
with a "page" address. Previously this method changes the state
of MipsGotSection because it modifies PageIndexMap field. That leads
to the unpredictable results if getPageEntryOffset called from multiple threads.
The patch makes getPageEntryOffset constant. To do so it calculates GOT
entry index but does not update PageIndexMap field. Later in the
MipsGotSection::writeTo method linker calculates "page" addresses and
writes them to the output.
llvm-svn: 288129
If output section which referenced by R_MIPS_GOT_PAGE or R_MIPS_GOT16
relocations is small (less that 0x10000 bytes) and occupies two adjacent
0xffff-bytes pages, current formula gives incorrect number of required "page"
GOT entries. The problem is that in time of calculation we do not know
the section address and so we cannot calculate number of 0xffff-bytes
pages exactly.
This patch fix the formula. Now it gives a correct number of pages in
the worst case when "small" section intersects 0xffff-bytes page
boundary. From the other side, sometimes it adds one more redundant GOT
entry for each output section. But usually number of output sections
referenced by GOT relocations is small.
llvm-svn: 288127
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
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
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
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
We have different functions to stringize objects to construct
error messages. For InputFile, we have getFilename, and for
InputSection, we have getName. You had to memorize them.
I think this is the case where the function overloading comes in handy.
This patch defines toString() functions that are overloaded for all these
types, so that you just call it in error().
Differential Revision: https://reviews.llvm.org/D27030
llvm-svn: 287787
Some synthetic sections are not derived calsses of SyntehticSection.
They are derived directly from InputSection. For consistencly, we should
use SyntheticSection.
llvm-svn: 287606
MIPS GOT handling is very different from other targets so it is better
to keep the code in the separatre section class MipsGotSection. This
patch introduces the new section and moves all MIPS specific code from
GotSection to the new class. I did not rename fields and methods in the
MipsGotSection class to reduce the diff and plan to do that by the
separate commit.
Differential revision: https://reviews.llvm.org/D26733
llvm-svn: 287150
This patch introduces the following changes:
- DynamicSection now inherits InputSection<ELFT> and was moved
to SyntheticSections.h/.cpp.
- Link and Entsize fields of DynamicSection are propagated to
its output section
- In<ELFT>::SyntheticSections was removed.
- Finalization of synthetic sections was removed from
OutputSection<ELFT>::finalize. Now finalizeSyntheticSections is
used instead.
Differential revision: https://reviews.llvm.org/D26603
llvm-svn: 286950
Summary:
This patch adds a ".comment" section to an output. The comment
section contains the linker's version string. You can now
find out whether a binary is created by LLD or not using objdump
command like this.
$ objdump -s -j .comment foo
foo: file format elf64-x86-64
Contents of section .comment:
0000 00474343 3a202855 62756e74 7520342e .GCC: (Ubuntu 4.
0010 382e342d 32756275 6e747531 7e31342e 8.4-2ubuntu1~14.
...
00c0 766d2f74 72756e6b 20323835 38343629 vm/trunk 285846)
00d0 004c696e 6b65723a 204c4c44 20342e30 .Linker: LLD 4.0
00e0 2e302028 7472756e 6b203238 36343036 .0 (trunk 286406
00f0 2900 ).
Compilers emits .comment section as well, so the output contains
both compiler and linker information.
Alternative considered:
I first tried to add a SHT_NOTE section because GNU gold does that.
A NOTE section starts with a header which contains content type.
It turned out that ld.gold sets type NT_GNU_GOLD_VERSION to their
NOTE section. So the NOTE type is only for GNU gold (surprise!)
Next, I tried to create ".linker-version" section. However, it seems
that reusing the existing ".comment" section is better because 1)
other tools already know about .comment section and is able to strip
it and 2) the result contans not only linker info but also compiler
info.
Differential Revision: https://reviews.llvm.org/D26487
llvm-svn: 286496
Rui Ueyama