search for: embeddedmetadata

On Feb 8, 2010, at 8:51 PM, Duncan Sands wrote: > this can be done using debug info. Check out > http://llvm.org/docs/SourceLevelDebugging.html Wow, that threw me for a loop. I'm using the 2.6 release, thinking I was up to date, but its debug output doesn't look anything like what's described in the above link. It appears to document the upcoming 2.7 version, which

On Feb 9, 2010, at 11:13 AM, Trevor Harmon wrote: > Is there any information about these changes and why they were > necessary? I think I found it: http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt Still looking for an API to access the metadata... Trevor

...ot;uses" of these values because metadata is maintained 'on the side'. This ensures that the optimizer is not influenced by auxiliary information. For example, !1 = { i32 42 } define void @foo() { %x = call i8 @llvm.something(metadata !1) } See http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt for more information. This metadata support is not useful if the auxiliary information is not referenced by any LLVM IR entity. This is a limiting factor. The proposed solution is to introduced NamedMetadata. The NamedMetadata is derived from GlobalValue. The NamedMetadata is an array of meta...

Hi All, I'd like to propose some extensions to LLVM that will make it substantially faster at manipulating debug info, and will make the general annotation mechanisms in LLVM much richer: http://nondot.org/sabre/LLVMNotes/EmbeddedMetadata.txt Thoughts welcome, -Chris

...Consider you are debugging a crash in optimized code: Hey, your program crashed somewhere in function foo in foo.o vs. Hey, your program crashed in function foo in region foo1.c:100 - foo1.c:120 Also preserving debug info about variable names can be useful. http://nondot.org/sabre/LLVMNotes/EmbeddedMetadata.txt > For llvm.readcyclecounter, I think it's fine to inhibit > optimizations. It's hard to understand what it means if it > doesn't :-). Do you have an example where being able to > do optimizations would be useful? > > Dan > I don't have a real example fo...

...ta is maintained 'on the side'. This ensures that the > optimizer is not influenced by auxiliary information. For example, > > !1 = { i32 42 } > > define void @foo() { > %x = call i8 @llvm.something(metadata !1) > } > > > See http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt for more > information. > > This metadata support is not useful if the auxiliary information is > not referenced by any LLVM IR entity. This is a limiting factor. The > proposed solution is to introduced NamedMetadata. The NamedMetadata is > derived from GlobalValue. So, the...

...This ensures that the >> optimizer is not influenced by auxiliary information. For example, >> >> !1 = { i32 42 } >> >> define void @foo() { >>  %x = call i8 @llvm.something(metadata !1) >> } >> >> >> See http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt for more >> information. >> >> This metadata support is not useful if the auxiliary information is >> not referenced by any LLVM IR entity.  This is a limiting factor. The >> proposed solution is to introduced NamedMetadata. The NamedMetadata is >> derived fr...

...fo for highly optimized code. They don't care at all about variable values, but it is very useful to have them attribute time samples to source lines (even if inherently fuzzy). > Also preserving debug info about variable names can be useful. > > http://nondot.org/sabre/LLVMNotes/EmbeddedMetadata.txt See also: http://nondot.org/sabre/LLVMNotes/DebugInfoImprovements.txt :) >> For llvm.readcyclecounter, I think it's fine to inhibit >> optimizations. It's hard to understand what it means if it >> doesn't :-). Do you have an example where being able to >>...

...hat. The notes should be considered to be part of the LLVM IR, and documented in langref (Devang, did you do this?). The metadata proposal I sent out would be a more appropriate way of handling cases where front-ends want to propagate arbitrary information. http://nondot.org/sabre/LLVMNotes/EmbeddedMetadata.txt -Chris

...maintained 'on the side'. This ensures that the > optimizer is not influenced by auxiliary information. For example, > > !1 = { i32 42 } > > define void @foo() { > %x = call i8 @llvm.something(metadata !1) > } > > > See http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt for more > information. > > This metadata support is not useful if the auxiliary information is > not referenced by any LLVM IR entity. This is a limiting factor. The > proposed solution is to introduced NamedMetadata. The NamedMetadata is > derived from GlobalValue. The Nam...

...track of exactly what we want to support. What about making MDNodes that refer to Instructions? Is that desired any more, or is that obsolete? I had a patch to do this locally and I either want to fix it up and commit it or discard it. The relevant section of my locally modified test/Feature/embeddedmetadata.ll reads: define void @foo() { ;; Intrinsic using MDNode and MDString %x = call i8 @llvm.something(metadata !21, i32 42, metadata !"bar") %y = call i8 @llvm.something( metadata !{i8 %x, i8 %y, i32 %z, metadata* @llvm.foo, null, i32* null, metadata undef, metadata !...

...= { i32 42 } >>> >>> >>> >>> define void @foo() { >>> >>> %x = call i8 @llvm.something(metadata !1) >>> >>> } >>> >>> >>> >>> >>> >>> See http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt for more >>> >>> information. >>> >>> >>> >>> This metadata support is not useful if the auxiliary information is >>> >>> not referenced by any LLVM IR entity. This is a limiting factor. >>> The >>> &gt...

Hi Devang, > All supported notes must be documented in LLVM language reference. Does this also mean that undocumented / unsupported notes are invalid? In particular, when I have a custom frontend and backend, using custom notes could be a great way to communicate between those, if the LLVM IR would allow unknown notes. Other than that, this seems like a decent approach. As Andrew pointed out,

Can we help in local variable debug info work. Dale Johannesen wrote: > On Apr 7, 2009, at 9:52 PMPDT, vasudev wrote: > > >> Thanks for the info regarding DebugLoc field. Another related >> question >> that I have is regarding debug info for local variables. With -fast >> option, ISD::DECLARE nodes are created in DAG for debug info of local >>

...even if inherently fuzzy). > Yes, I need something similar to that too, see above. (Analysis pass that can give messages containing original source:line info). > >> Also preserving debug info about variable names can be useful. >> >> http://nondot.org/sabre/LLVMNotes/EmbeddedMetadata.txt >> > > See also: > http://nondot.org/sabre/LLVMNotes/DebugInfoImprovements.txt > > :) > > Thanks for the pointer. >>> For llvm.readcyclecounter, I think it's fine to inhibit >>> optimizations. It's hard to understand what it means i...

Thanks for the quick responses. "disappearing function calls" is by far the preferred way for me, as I want my pass to work with standard LLVM and not a hacked version that supports extra pragmas, or intrinsics. I am just new to LLVM and wanted to make sure that there isn't already a mechanism for passing meta-data between the user and the optimizer. I am planning to

Pre-empting Chris's inevitable response: don't add intrinsics! I really like the 'disappearing function calls' idea. Chris suggested practically the same thing for a previous question about adding BigInt support. Anthony, whichever route you take in the end, please consider documenting your 'code adventure' on the wiki so others can learn from your experience. Justing

Hi Evan Thanks for the email. I had a look at gcc implementation of TBAA and I think three main steps in implementation of TBAA for LLVM will be this: April 20 ~ May 23: I will read gcc implementation in depth and play around with LLVM code. May 23 ~ July 6: Implementation and test of a simple version of TBAA that does not work with all aggregate types. I think part of the coding required for

Here is a proposal that I mentioned sometime ago. Any thoughts,comments or suggestions on this proposal would be appreciated. - Devang // = = =---------------------------------------------------------------------- ===// // Function Notes (or Traits) // = = =---------------------------------------------------------------------- ===// This document describes the

...declare "success", but it is worthwhile, and important and useful steps can be made without solving the whole problem. This proposal should solve half of this problem. That is to keep the line number information with optimization code. (From Chris)<http://www.nondot.org/sabre/LLVMNotes/EmbeddedMetadata.txt> The following sub-sections define specific requirements to improve the debug information in LLVM. *2.1 ** Verification Flow* The most important of this project is to make the debug information do not block any optimization by LLVM transform passes. Here I propose a way to determin...