similar to: TableGen pseudo lowering

Hi all, I'm trying to solve a problem that we have in implementation of the assembler for Mips platform in llvm. Mips has some pseudo instructions that, depending on the arguments can be emitted as one or more real instructions by the assembler. For example load immediate instruction can have multiple expansions depending on a size of immediate operand: This expansion is for 0 ≤ j ≤ 65535. li

Hi Vladimir, The pass you refer to isn't used by the assembler at all. That's strictly a compiler codegen thing. The assembler equivalents are expressed via InstAlias constructions. Again, though, those are for a single output instruction, so you need something more. Sprecifically, you can handle assembly pseudo-instructions in C++ code. Something like the ARM assembler's

Hi Jim, thank you for the quick response. I have used InstAlias in some cases, but these are really simple pseudo instructions where the pseudo instruction is more like a special case of existing one, like using fixed operand or simply a more human understandable way of presenting an operation. I know that there are predicates available to improve matching, but can InstAlias use conditions to

I included the ability to get/set an operand by name because I thought it would be easier to copy+modify an existing DAG by specifying the name of the operand you want to replace rather than having to remember its position. For example, if you want to replace the first source, isn't it easier to specify $src than remember it's the second operand? Perhaps the people actually coding these

I understood that the name is a matching tag for the operand and not its name (as in named macro or function arguments). However, I was assuming that the names in any one DAG node had to be unique and so could serve as selectors for operands. But a quick investigation shows that I was wrong: names can be duplicated in the same node. So DAG indexes are integers only. At 10/12/2020 01:46 PM,

On Tue, Oct 13, 2020 at 10:47 AM Madhur Amilkanthwar <madhur13490 at gmail.com> wrote: > What do you guys think about the below enhancements? > > 5. !getdagrestype(dag [, index]) - Returns type of result value. If the DAG computes multiple values then return type of 'index'th result. > > 6. !setdagrestype(dag target_dag, type T [, index]) - Set return type of

This is a proposal to enhance TableGen's ability to analyze and manipulate DAGs. Hopefully this will allows more complex DAGs to be built in TableGen. 1. Add a new value suffix. value(index) The value must be a DAG. The index specifies the operator or an operand, whose value is produced. The index can be 0 produce the operator 1...n produce operand by

Now that I've learned my way around TableGen just a bit, I'd like to solicit suggestions for improving and enhancing it. Perhaps there are some lexical changes that could improve readability of .td files (e.g., I'm planning to enhance the lexer to allow an apostrophe as a digit group separator in integers, a la C++). Perhaps there are some syntactic enhancements that would make .td

I was wondering today whether the TableGen DAG support would be more useful if you could manipulate DAGs a little more easily. Right now, you can: * Specify a DAG with (...) * Catenate DAGs with !con(). * Construct a DAG with !dag(). * Iterate over a DAG with !foreach(). * Get and set the DAG operator with !getop() and !setop(). What if you could also get and set a DAG's operands

Thank you for driving this Paul, I agree that it is better to have one doc on TableGen. This has been a point of confusion for me as well - when I land in the wrong one and can’t find what I’m looking for :-). -Chris > On Jul 31, 2020, at 1:49 PM, Paul C. Anagnostopoulos via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Thanks, David. I have started a new document titled

I certainly agree that there are a boatload of CMake options. I haven't even scratched the surface. In keeping with your suggestion: Is there a way to tell Ninja to build just one target machine? At 10/7/2020 02:58 PM, Nicolai Hähnle wrote: >Hi Paul, > >On Wed, Oct 7, 2020 at 3:33 PM Paul C. Anagnostopoulos via llvm-dev ><llvm-dev at lists.llvm.org> wrote: >>

John, I'm pretty much down to details and smoothing the text. Here is a pdf. Can you mark it with comments? Or you can send an email with a list. I will incorporate your comments and send you a second proof, so you can be sure I understood you. Is a week long enough? ~~ Paul At 8/5/2020 02:16 PM, John Byrd wrote: >I'd like to collaborate, if you point me at your tree. Like you,

A question for all you TableGen aficionados: Does anyone know why the collection of RecordVal field values stored in a Record are represented by a SmallVector rather than some sort of map? This means that every time a record field is looked up by name, a linear search is performed. Is it a question of RAM usage?

I'm pondering a new timing feature for TableGen and am wondering whether anyone uses the existing -time-regions option. Some instrumentation for it appears in CodeGenTarget.cpp and GICombinerEmitter.cpp but nowhere else. If no one is using it, I'll be tempted to remove it.

I'm glad you find it useful. I haven't thought about it being done as part of the build, nor am I any sort of build guru. What do other people think? At 10/7/2020 08:12 AM, Nemanja Ivanovic wrote: >This is really useful. Is there a way to produce this output automatically (by providing some CMake variable)? For example, something like: >-DBUILD_TBLGEN_DEBUG=<Target> >

Well, I was hinting at LLVM_DEBUG messages. You can pretty much dump all "actions" Tablegen would take to process a .td file, which should suffice, IMO. On Wed, Aug 5, 2020 at 5:59 PM Paul C. Anagnostopoulos <paul at windfall.com> wrote: > Your reply suggests that there is a way to see debug messages from > TableGen. Is that what you meant? If so, can you explain how that

Are all the records collected as they are parsed, with template parameter substitution and lets, and *then*, after all records are collected, a "pass" is made to calculate the inter-field expressions? Once I understand this, I will add a section to the new guide to explain it. I presume it is the case that this behavior should be publicized. It also appears to be the case that a record

I’d like to propose that Paul C. Anagnostopoulos takes on the role as the code owner of TableGen. This is a critical tool in LLVM and Paul has been doing a great job making across the board upgrades to it. Any concerns? -Chris

Yes, I understand the problem. To be more useful, TableGen would have to carry the traces along with the classes and records and (re)display the values while the substitutions are being made. I'm writing a new Programmer's Guide for TableGen and have been digging into the parse-time versus substitution-time issue. I haven't found a document that makes it clear. Can you give a quick

Let's say I wanted to start writing a document on how to create a backend for TableGen. Such a document is suggested in "TableGen Backends." Should I describe the classes that are available to the backend in detail, or should I spend time updating the Doxygen comments in the class header files and simply present an overview in the document?