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
When an output section has no byte commands and has no input sections then it
would be ideal if the type of the section is SHT_NOBITS so that the file can
take up less space. This change sets the default type of of output sections to
SHT_NOBITS instead of SHT_PROGBITS to allow this. This required some minor test
changes (which double as tests for this new behavior) but extend-pt-load.s had
be changed in a non-trivial way. Since it seems to me that the point of the
test is to point out the consequences of how flags are assigned to output
sections that don't have input sections I changed the test to work and still
show how the memsize of the executable segment was changed.
Differential Revision: https://reviews.llvm.org/D41082
llvm-svn: 320437
An output section can include elements from two input sections with
different sh_entsize. When that happens the output section itself
should not have a sh_entsize.
llvm-svn: 318311
No difference in practice other than having sh_entsize in the output.
This should simplify the patch for handling SHF_MERGE in -r.
Based on a patch by George Rimar.
llvm-svn: 318306
InputSections may contain MergeInputSection members which trigger
a segmentation fault when trying to cast them to InputSection.
Differential Revision: https://reviews.llvm.org/D33628
llvm-svn: 304189
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
Currently lld will implicitly reserve space for the headers. This is
not the case is bfd, where it is the script responsibility to use
SIZEOF_HEADERS. This means that a script not using SIZEOF_HEADERS and
expecting the address of the first section to be 0 would fail with lld.
I am fixing that is the next commit. This one just makes the tests
explicitly use SIZEOF_HEADERS to avoid the dependency on the current
behaviour.
llvm-svn: 282814
Since they end up going on the same PT_LOAD, there is no reason to
sort them. This matches bfd's behaviour and is user visible in the
placement of orphan sections.
llvm-svn: 282799
In most cases that means just not checking the address when we don't
need it.
For some tests it is easier to just set . to a known value.
llvm-svn: 281976
This fixes pr30367, but more importantly, it changes how we compute offsets.
Now offset computation in a walk over linker script commands, like the
rest of assignAddresses. IMHO this is simpler to understand and if we
ever have to create multiple outputsections or chunks to change how we
handle test/ELF/linkerscript/alternate-sections.s it should be easier
to do it.
llvm-svn: 281736
Previously we combined sections by name if linkerscript was used.
For that we had to disable SHF_MERGE handling temporarily, but then
found that implementing it properly will require additional complexity layers like
subsections or something.
At the same time looks we can live with multiple output sections approach for now.
That patch do this change.
Differential revision: https://reviews.llvm.org/D24127
llvm-svn: 280801
Fangrui Song