Displaying 20 results from an estimated 3000 matches similar to: "RFC: LLD: creating linker-generated sections as input sections instead of output sections"
2016 Oct 19
2
LLD: creating linker-generated sections as input sections instead of output sections
I would suggest converting only part of linker generated sections to
input sections to reduce amount of code changes.
For example it's unlikely that SymbolTableSection or
StringTableSection would ever require such treatment, so why
converting them to input sections?
2016-10-19 11:03 GMT+03:00 George Rimar <grimar at accesssoftek.com>:
>>This idea popped up in the review thread
2016 Oct 19
3
LLD: creating linker-generated sections as input sections instead of output sections
On Wed, Oct 19, 2016 at 3:34 AM, Peter Smith via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Thanks for the RFC.
>
> I'm in favour of the option of creating InputSections for some linker
> generated content. I think it would add extra flexibility to the
> linker. ARM's proprietary linker uses the equivalent of InputSections
> with a pseudo linker defined
2017 Mar 10
3
[ELF] [RFC] Padding between executable sections
Hi,
I was doing some experiments with LLD and noticed that it pads out
OutputSections with null bytes in all cases (as far as I could tell).
However, for executable sections on some targets, 0x00 forms part of an
executable instruction that is not nop. In particular, for x86_64 targets
at least, the sequence 0x00 0x00 is an add instruction. This can result in
confusing disassembly.
For example,
2016 Jun 21
2
[LLD] thunk implementation correctness depends on order of input section.
I've been working on supporting ARM/Thumb interworking thunks in LLD
and have encountered a limitation that I think it is worth bringing up
in a wider context. This is all LLD specific, apologies if I've abused
llvm-dev here.
TL;DR summary:
- Thunks in lld may not work if they are added to InputSections that
have already been scanned.
- There is a short term fix, but in the longer term I
2017 Sep 19
1
Do I need to modify the AddrLoc of LLD for ARC target?
Hello Leslie,
The errors coming from the gnu assembler are due to the file being
assembled in Arm state, to get rid of the errors you'll either need to
put a .thumb directive in the file, or pass -mthumb to the assembler
via arm-linux-gnu-gcc -Wa,-mthumb (I think).
I'm not able to explain what you are seeing in your print out as it
doesn't quite match the map file. Looking at your
2017 Sep 18
1
Do I need to modify the AddrLoc of LLD for ARC target?
Hello Leslie,
I don't know quite what to say as I don't know precisely what your
question is? If I am not being precise enough please can you put some
explicit questions in? From what I can see in the output, here are
some comments.
>From your arc mapfiles it looks like that in the output both linker's
have given the .text output section the correct base address given the
2020 Nov 18
1
LTO with Linker Scripts
On 2020-11-18, Teresa Johnson via llvm-dev wrote:
>AFAIK this effort stalled when Tobias changed jobs. Adding Sergei who may
>know the current status of the support within Qualcomm.
>
>Teresa
>
>On Wed, Nov 18, 2020 at 11:12 AM Mitra, Gaurav via llvm-dev <
>llvm-dev at lists.llvm.org> wrote:
>
>> Hello All,
>>
>>
>>
>> I’d like to pick up
2017 Sep 14
4
Do I need to modify the AddrLoc of LLD for ARC target?
Hello Leslie,
I think we are going to need to know a bit more about the ELF ABI for
what looks like the ArcCompact before we can help you.
LLD's calculation of P (the place to be relocated) is as it is in the
generic ELF specification. The Rel.Offset corresponds to the ELF
r_offset field. This is covered by: "For a relocatable file, the value
is the byte offset from the beginning of the
2017 Jul 31
3
[RFC] Profile guided section layout
Hi Rafael,
On 07/31/2017 04:20 PM, Rafael Avila de Espindola via llvm-dev wrote:
> However, do we need to start with instrumentation? The original paper
> uses sampling with good results and current intel cpus can record every
> branch in a program.
>
> I would propose starting with just an lld patch that reads the call
> graph from a file. The format would be very similar to
2020 Mar 27
2
[lld] RFC: Allow custom sections to be under GNU_RELRO
Peter,
Thanks for the great feedback!
> The first is the use of a custom suffix, all other linker conventions,
that I know of, use prefixes as these are much easier and faster to match
against names.
> This can be important in large programs compiled -ffunction-sections as
there can be millions of sections to match.
I understand the reason of having these conventions in linkers. On the
2020 Mar 26
2
[lld] RFC: Allow custom sections to be under GNU_RELRO
Hey,
We would like to propose an idea that would help security harden
applications that define custom sections.
Motivation and Background
In Chromium we have a garbage collector that implements some RTTI machinery
in the form of a table. This table is used by the collector to trace and
finalize garbage collected objects. We're thinking of using
__attribute__((section(...))) so that the table
2016 Feb 03
2
lld dynamic relocation creation issue
Hi all,
Working on lld aarch64 support I came across an issue where I am not sure which
would be best design approach to solve.
The aarch64 R_AARCH64_ABS64 relocation for PIC/PIE build requires a dynamic
relocation (R_AARCH64_RELATIVE) with the value set as the addend of the
relocation. For instance, when linking the crtbeginS.o which contains:
Relocation section '.rela.init_array' at
2017 Jan 04
5
RFC: LLD range extension thunks
I'm about to start working on range extension thunks in lld. This is
an attempt to summarize the approach I'd like to take and what the
impact will be on lld outside of thunks. I'm interested if anyone has
any constraints the approach will break, alternative suggestions, or
is working on something I'll need to take account of?
I expect range extension thunks to be important for
2017 Apr 05
4
[LLD] RFC Range Thunks Implementation review for ARM and Mips
Are you suggesting other linker jobs such as creating _end symbols to the
linker script?
The linker script support was implemented after we wrote the current Writer
class, so it is somewhat "plugged in" to the Writer. It might not be the
best design, and not many other options have been explored. So there might
be room to improve code by moving work loads from the Writer to the
2020 Mar 30
2
LLD bug causing objcopy ELF to binary generation to create large binaries
Hi Andrew,
Thanks for the background and context.
"In your issue, just to clarify, is the ELF output from LLD also
"large", or is it just the output from the llvm-objcopy operating on
that ELF that is "large"? Do you have a simple sample to demonstrate
this issue?"
The ELF size is actually smaller, compared to what was generated from
LLVM 7.x. (~900Kb vs
2016 Oct 21
2
LLD: creating linker-generated sections as input sections instead of output sections
> Is anyone already working on it? If not then I can take this task.
Me - not.
George.
2017 Apr 04
2
[LLD] RFC Range Thunks Implementation review for ARM and Mips
This RFC is primarily to support the review of the range extension
thunks implementation of lld. This concerns ARM and Mips as all of the
thunk creation step is skipped over if the target doesn't need thunks.
Mips LA25 Thunks are not range extension Thunks but these are
generated using the same code, I've kept the behaviour the same as it
is now, although the implementation is obviously
2017 Jan 05
2
RFC: LLD range extension thunks
Hello Rui,
Thanks for the comments
- Synthetic sections and rewriting relocations
I think that this would definitely be worth trying. It should remove
the need for thunks to be represented in the core data structures, and
would allow .
It would also mean that we wouldn't have to associate symbols with
thunks as the relocations would directly target the thunks. ARM
interworking makes reusing
2018 May 15
1
[RFC] (Thin)LTO with Linker Scripts
Hi Peter,
On Mon, May 14, 2018 at 8:14 AM Peter Smith via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> My understanding from the RFC is:
> - All global objects in the bitcode file will be assigned a section name.
>
... which is equal to the section name that they would have been emitted to
if this was a regular compilation. In addition to allowing the linker to
read section
2016 Jan 21
3
Need to refactor relocation handlers in ELF LLD
We have fairly large and complex code to handle relocations in Writer.cpp,
Target.cpp, OutputSections.cpp and InputSections.cpp. They started with
simple code, but because each patch added a small piece of code to the
existing one, it is becoming out of control now. For example, we have lots
of entangled boolean flags in the functions that interfere with each other
in an obscure fashion. Even I