Fix https://github.com/llvm/llvm-project/issues/53073
In case of a relocation error, GNU ld's link map includes
the archive member extraction information but not output sections.
Our -Map and --why-extract= are currently no-op in case of an error.
This change makes the two options work.
Reviewed By: ikudrin, peter.smith
Differential Revision: https://reviews.llvm.org/D116838
This adds thin archives to the map file test.
I noticed that we had this test-case in our downstream
testsuite but it wasn't in the upstream testing.
Differential revision: https://reviews.llvm.org/D107555
A repeated typo in lld/test/ELF/map-file.s prevented a number of checks from being executed.
CHECk-NEXT -> CHECK-NEXT
^ ^
After correcting the typo, a small adjustment was needed to match the size of the synthetic .comment section (which always contains "LLD 1.0" in the test environment).
Differential revision: https://reviews.llvm.org/D88023
Summary:
Based on Peter Collingbourne's suggestion in D56828.
Before D56828: PT_LOAD(.data PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) .bss)
Old: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) .data .bss)
New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro)) PT_LOAD(.data. .bss)
The new layout reflects the runtime memory mappings.
By having two PT_LOAD segments, we can utilize the NOBITS part of the
first PT_LOAD and save bytes for .bss.rel.ro.
.bss.rel.ro is currently small and only used by copy relocations of
symbols in read-only segments, but it can be used for other purposes in
the future, e.g. if a relro section's statically relocated data is all
zeros, we can move it to .bss.rel.ro.
Reviewers: espindola, ruiu, pcc
Reviewed By: ruiu
Subscribers: nemanjai, jvesely, nhaehnle, javed.absar, kbarton, emaste, arichardson, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58892
llvm-svn: 356226
Old: PT_LOAD(.data | PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .bss)
New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .data .bss)
The placement of | indicates page alignment caused by PT_GNU_RELRO. The
new layout has simpler rules and saves space for many cases.
Old size: roundup(.data) + roundup(.data.rel.ro)
New size: roundup(.data.rel.ro + .bss.rel.ro) + .data
Other advantages:
* At runtime the 3 memory mappings decrease to 2.
* start(PT_TLS) = start(PT_GNU_RELRO) = start(RW PT_LOAD). This
simplifies binary manipulation tools.
GNU strip before 2.31 discards PT_GNU_RELRO if its
address is not equal to the start of its associated PT_LOAD.
This has been fixed by https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2731e0c374e5323ce4cdae2bcc7b7fe22da1a6f
But with this change, we will be compatible with GNU strip before 2.31
* Before, .got.plt (non-relro by default) was placed before .got (relro
by default), which made it impossible to have _GLOBAL_OFFSET_TABLE_
(start of .got.plt on x86-64) equal to the end of .got (R_GOT*_FROM_END)
(https://bugs.llvm.org/show_bug.cgi?id=36555). With the new ordering, we
can improve on this regard if we'd like to.
Reviewers: ruiu, espindola, pcc
Subscribers: emaste, arichardson, llvm-commits, joerg, jdoerfert
Differential Revision: https://reviews.llvm.org/D56828
llvm-svn: 356117
This generalizes the old heuristic placing SHT_DYNSYM SHT_DYNSTR first in the readonly SHF_ALLOC segment.
Reviewers: espindola
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D48406
llvm-svn: 335674
This CL places .dynsym and .dynstr at the beginning of SHF_ALLOC
sections. We do this to mitigate the possibility that huge .dynsym and
.dynstr sections placed between ro-data and text sections cause
relocation overflow.
Differential Revision: https://reviews.llvm.org/D45788
llvm-svn: 332374
This CL is to mitigate R_X86_64_PC32 relocation overflow problems for huge binaries that has near 4G allocated sections.
By examining those binaries, there're 2 issues contributes to the problem:
1). huge ".dynsym" and ".dynstr" stands in the way between .rodata and .text
2). _init_array_start/end are placed at 0 if no ".init_array" presents, this causes .text relocation against them become more prone to overflow.
This CL addresses 1st problem (the 2nd will be addressed in another CL.) by assigning a smaller sortrank to .dynsym and .dynstr thus they no longer stand in between.
llvm-svn: 332038
Summary: This is not technically required, but glibc unwind-dw2-fde.c classify_object_over_fdes expects there is a CIE record length 0 as a terminator.
Reviewers: ruiu, espindola
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D46566
llvm-svn: 331708
This is slightly simpler to read IMHO. Now if a symbol has a position
in the file, it is Defined.
The main motivation is that with this a SharedSymbol doesn't need a
section, which reduces the size of SymbolUnion.
With this the peak allocation when linking chromium goes from 568.1 to
564.2 MB.
llvm-svn: 330966
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
Currently, LLD prints VA, but not LMA in a map file.
It seems can be useful to print both to reveal layout
details and patch implements it.
Differential revision: https://reviews.llvm.org/D44899
llvm-svn: 329271
Newer versions of the gnu assembler produce a X86_64_PLT32 for
calls. There is a change under review in llvm to do the same, so update
the tests to not depend on it.
We can still produce a R_X86_64_PC32 with ".long foo - .".
llvm-svn: 325379
As mentioned in PR35471, shared functions for which
.plt entry address is used shows up in bfd's map files.
Patch teaches LLD to do the same.
Differential revision: https://reviews.llvm.org/D40839
llvm-svn: 319879
With fix:
Specify -soname for input dso to fix up the .dynstr section
size in different environments.
Original commit message:
As mentioned in PR35471, copied symbols did not show
in --Map output. Patch fixes that.
Differential revision: https://reviews.llvm.org/D40785
llvm-svn: 319769
As mentioned in PR35471, copied symbols did not show
in --Map output. Patch fixes that.
Differential revision: https://reviews.llvm.org/D40785
llvm-svn: 319747
to separate commons based on file name patterns. The following linker script
construct does not work because commons are allocated before section placement
is done and the only synthesized BssSection that holds all commons has no file
associated with it:
SECTIONS { .common_0 : { *file0.o(COMMON) }}
This patch changes the allocation of commons to create a section per common
symbol and let the section logic do the layout.
Differential revision: https://reviews.llvm.org/D37489
llvm-svn: 312796
This is PR33886,
previously we did not output common symbols to map,
patch fixes that.
Differential revision: https://reviews.llvm.org/D36466
llvm-svn: 310703
Previously, we printed out input sections and input files in
separate columns as shown below.
Address Size Align Out In File Symbol
0000000000201000 0000000000000015 4 .text
0000000000201000 000000000000000e 4 .text
0000000000201000 000000000000000e 4 foo.o
0000000000201000 0000000000000000 0 _start
0000000000201005 0000000000000000 0 f(int)
000000000020100e 0000000000000000 0 local
0000000000201010 0000000000000002 4 bar.o
0000000000201010 0000000000000000 0 foo
0000000000201011 0000000000000000 0 bar
This format doesn't make much sense because for each input section,
there's always exactly one input file. This patch changes the format
to this.
Address Size Align Out In Symbol
0000000000201000 0000000000000015 4 .text
0000000000201000 000000000000000e 4 foo.o:(.text)
0000000000201000 0000000000000000 0 _start
0000000000201005 0000000000000000 0 f(int)
000000000020100e 0000000000000000 0 local
0000000000201010 0000000000000002 4 bar.o:(.text)
0000000000201010 0000000000000000 0 foo
0000000000201011 0000000000000000 0 bar
Differential Revision: https://reviews.llvm.org/D32657
llvm-svn: 301683
We found that some part of code for the -Map option takes O(m*n)
where m is the number of input sections in some file and n is
the number of symbols in the same file. If you do LTO, we usually
have only a few object files as inputs for the -Map option
feature, so this performance characteristic was worse than I
expected.
This patch rewrites the -Map option feature to speed it up.
I eliminated the O(m*n) bottleneck and also used multi-threading.
As a result, clang link time with the -Map option improved from
18.7 seconds to 11.2 seconds. Without -Map, it takes 7.7 seconds,
so the -Map option is now about 3x faster than before for this
test case (from 11.0 seconds to 3.5 seconds.) The generated output
file size was 223 MiB, and the file contains 1.2M lines.
Differential Revision: https://reviews.llvm.org/D32631
llvm-svn: 301659
As with the changes made in r297645, we do not want a potentially long link to
be run, if it will ultimately fail because the map file is not writable. This
change reuses the same functionality as the output file path check. See
https://reviews.llvm.org/D30449 for further justification and explanations.
Reviewers: ruiu
Differential Revision: https://reviews.llvm.org/D31603
llvm-svn: 299420
This reverts commit r296378.
I am pretty sure this is incorrect. In particular, for just
.cfi_startproc
nop
.cfi_endproc
We now add an extra 4 zeros that neither bfd nor gold add.
llvm-svn: 296503
Patch by Mark Kettenis.
Currenlty ld.lld does not add a terminator (a CIE with its length field
set to zero) to the .eh_frame sections it generates. While the relevant
standards (the AMD64 SysV ABI and the Linux LSB) are not explicit about
this, such a terminator is expected by some unwinder implementations and
seems to be always emitted by ld.bfd. In addition to that, the Linux LSB
https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html#EHFRAME
explicitly says that
The .eh_frame section shall contain 1 or more Call Frame Information
(CFI) records.
Currently, if the .eh_frame sections of the input files only contain
terminators, ld.lld emits a zero=sized .eh_frame section
which clearly doesn't meet that requirement.
The diff makes sure a terminator gets added to each .eh_frame section
and adjusts all the relevant tests to account for that. An additional
test isn't needed as these adjustments mean that the existence of the
terminator is tested for by several tests already.
Differential Revision: https://reviews.llvm.org/D30335
llvm-svn: 296378
With this we complete the transition out of special output sections,
and with the previous patches it should be possible to merge
OutputSectionBase and OuputSection.
llvm-svn: 296023
With a synthetic merge section we can have, for example, a single
.rodata section with stings, fixed sized constants and non merge
constants.
I can be simplified further by not setting Entsize, but that is
probably better done is a followup patch.
This should allow some cleanup in the linker script code now that
every output section command maps to just one output section.
llvm-svn: 294005
Previously, we were printing out something like this for
sections/symbols with alignment 16
0000000000201000 0000000000000182 10 .data
which I think confusing. I think printing it in decimal is better.
Differential Revision: https://reviews.llvm.org/D29258
llvm-svn: 293685
This patch adds a test for an invalid output path for -Map option,
though that test is not for verifying that we are using error()
instead of fatal() in writeMapFile.
llvm-svn: 292336
Fangrui Song