similar to: [LLVMdev] Fwd: [llvm-commits] Proof of concept patch for unifying the .s/ELF emission of .ARM.attributes

On Thu, Oct 21, 2010 at 7:50 AM, Rafael Espíndola <rafael.espindola at gmail.com> wrote: >> Hmm, I wish we had this discussion way earlier.. >> >> How would I emit things in different subsections? I can do a high >> level switch to .ARM.attributes, and if I were emitting one blob from >> begin to end, using the higher level interface would be preferable,

> Hmm, I wish we had this discussion way earlier.. > > How would I emit things in different subsections? I can do a high > level switch to .ARM.attributes, and if I were emitting one blob from > begin to end, using the higher level interface would be preferable, > but it contains additional subsections - which are naturally > represented by MCDataFragments - Is there an MC

2010/10/21 Jason Kim <jasonwkim at google.com>: > That is exactly what I need - I need a nice MC way to output a at > least two different 4 byte size fields after all of the blobs in the > .ARM.attributes are sent out. Hi Jason, If I got it right, you need to write to the attributes section after you have moved out to print the rest of the file. I can't think of an example

> Also what is the preferred method for MC way of setting out subsection > sizes after the fact? I am guessing I need to use an MCFixup? > How do I get an MCExpr to evaluate a method for the subsection size? > Is there an equivalent use in the places using MCFixup? > Do I need to add a new subclass to MCExpr for doing this? > > JimG, can you please comment on the MachO

On Thu, Oct 21, 2010 at 11:42 AM, Rafael Espíndola <rafael.espindola at gmail.com> wrote: >> Also what is the preferred method for MC way of setting out subsection >> sizes after the fact? I am guessing I need to use an MCFixup? >> How do I get an MCExpr to evaluate a method for the subsection size? >> Is there an equivalent use in the places using MCFixup? >>

---------- Forwarded message ---------- From: Jason Kim <jasonwkim at google.com> Date: Fri, Oct 22, 2010 at 12:59 PM Subject: Re: [llvm-commits] Fwd: Proof of concept patch for unifying the .s/ELF emission of .ARM.attributes To: Rafael Espíndola <rafael.espindola at gmail.com> On Fri, Oct 22, 2010 at 12:51 PM, Jason Kim <jasonwkim at google.com> wrote: > On Thu, Oct 21,

2010/10/21 Jason Kim <jasonwkim at google.com>: > Of the 45 remaining, there are 4 interesting uses in MCAsmStreamer.cpp > - (I suppose for emitting data constants in a cross platform manner) > The other remaining uses are in AsmPrinter, again to do cross platform things. > It seems a bit strange to use a high level hammer to do ballpeen > work..... But when in Rome.... :-)

OK, after reading the docs I have some extra comments (and an updated patch). *) To support per section or per symbol attributes we would have to move this to the processing done in the end of the file. Lets not do this right now. *) We don't currently use any string attributes, so I did not implement them. *) Having an attribute emitter class is a nice way to separate the job of creating the

I also noticed that we were trying to optimize the output of 41 bytes of data :-) The attached patch is similar to the previous one but drops the API changes by just accumulating the attributes locally before outputting them. Cheers, Rafael -------------- next part -------------- A non-text attachment was scrubbed... Name: attrs.patch Type: text/x-patch Size: 12333 bytes Desc: not available URL:

Hi Jim, Thanks for reviewing the patch. I couldn't get rid of STLExtras.h, but other than that, I followed all the suggestions in your email. Please let me know if you notice anything else that needs fixing. On Thu, Mar 22, 2012 at 4:42 PM, Jim Grosbach <grosbach at apple.com> wrote: > Hi Akira, > > This is looking good. Some specific comments on the details below. > >

Hi Akira, Just two very minor things that I missed the first time around. 1. The 'fixup" member of ELFRelocation entry should be "Fixup" instead. 2. Since we're always passing in a non-NULL fixup, that should probably be a reference, not a pointer. Good for commit with those tweaks. Thanks! -Jim On Mar 23, 2012, at 1:07 PM, Akira Hatanaka wrote: > Hi Jim, >

Hi Akira, This is looking good. Some specific comments on the details below. Thanks! Jim > diff --git a/include/llvm/MC/MCELFObjectWriter.h b/include/llvm/MC/MCELFObjectWriter.h > index 6e9f5d8..220ecd0 100644 > --- a/include/llvm/MC/MCELFObjectWriter.h > +++ b/include/llvm/MC/MCELFObjectWriter.h > @@ -13,6 +13,7 @@ > #include "llvm/MC/MCObjectWriter.h" >

Hi Jack, Everything should be already using the sized Emit* routines directly rather than outputting individual bytes of larger entities piecemeal. Have you found that not to be the case? The Emit* routines handle endianness for you, so you shouldn't have to do much beyond that. For example, here's the EmitInvValue() implementation that underlies things and does the endianness transform:

Hi Jack, I would have expected the Mips backend to be using these routines (or more likely something on top of them) to emit the contents of the data and text sections and thus have the bit-twiddling done by these routines. I take it that's not happening? Basically, this should already work without any additional infrastructure. If it's not, something is broken and bypassing the

Jim, I see routines that are already available to do the endianizing, but the data and text section contents don't have sizing for the individual elements as far as I can see so that I can endianize them. That is the part I am trying to solve, not the bit twiddling algorithm. Did I miss something? Jack ________________________________________ From: Jim Grosbach [grosbach at apple.com] Sent:

Hi all, Just wanted to report that I've found a second way to achieve data/code layout (the first being the linker script that Eugene mentioned). The key is that gnu as supports a feature called subsections. http://sourceware.org/binutils/docs-2.20/as/Sub_002dSections.html#Sub_002dSections The way this works is that you can put stuff into a section like '.text 2', where 2 is a

> There is one complication though. LLVM (and GCC as well) don't support > subsections. While you can define what section globals and functions > are in, this doesn't support defining the subsection. If you say to > LLVM, put function f in section "text 12", it produces assembly like: > > .section text 12,"rw" @progbits This seems easy to fix during

Hi Zach (or anyone else who may have a clue), I'm currently investigating making use of LLVM for PDB parsing for with a view to supporting partial PDBs as produced by /DEBUG:FASTLINK as the VS DIA SDK hasn't been updated to handle them. I know this is probably low on your priority list but since /DEBUG:FASTLINK is now the implied default for VS2017 I figure it's a good time to take a

Hi all, The AsmPrinter class supports functions like EmitInt8, EmitInt16, and EmitInt32 for writing a 1/2/4 byte directive to the assembly. Each of these calls the MCStreamer::EmitIntValue method with the corresponding size. For some reason, there is no EmitInt64, and I was wondering if there was a fundamental reason why? The EmitIntValue function appears to support 8-byte inputs. I dug into

DWARF already needs to emit 64-bit values, being the type-unit hashes. How is that being done? (If it's going directly to the streamer, then we're already assuming all assemblers are okay with what the streamer does, and adding an AsmPrinter helper seems very reasonable.) --paulr From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of James Henderson via llvm-dev Sent: