Error in Kaleidoscope Chapter3

Beginners
#1

I am working on understand Chapter 3 of the Kaleidoscope example. While doing so I tried the example code; i.e.,

I compiled this program using
clang++ toy.cpp -o toy -g -lLLVM-11

I fed the example Kaleidoscope source code from Chapter one
https://llvm.org/docs/tutorial/MyFirstLanguageFrontend/LangImpl01.html
in to the corresponding program; i.e.

# Compute the x'th fibonacci number.
def fib(x)
  if x < 3 then
    1
  else
    fib(x-1)+fib(x-2)

# This expression will compute the 40th number.
fib(40)

I called the example program toy.kal. When I run
toy < toy.kal
I get the output below which has unexpected errors in it; i.e., it is as if the example toy.kal is not a valid Kaleidoscope program ?

./toy < tol.kal
ready> ready> Error: Unknown variable name
ready> Error: Unknown variable name
ready> Error: Unknown variable name
ready> Read top-level expression:define double @__anon_expr() {
entry:
  ret double 1.000000e+00
}

ready> Error: Unknown variable name
ready> Error: Unknown function referenced
Error: Unknown function referenced
ready> Error: Unknown function referenced
ready> ; ModuleID = 'my cool jit'
source_filename = "my cool jit"
#2

Chapter 5 will add the control flow support. So if you compile chapter 5 source code with “clang++ -g toy.cpp llvm-config --cxxflags --ldflags --system-libs --libs core orcjit native -O3 -o toy” and then run that toy.kal, it should work fine.

#3

I have tried to switch to the Chapter5 vrersion of toy.cpp and get the following error:

KaleidoscopeJIT.h:24:10: fatal error: 'llvm/ExecutionEngine/Orc/TargetProcessControl.h' file not found

It appears that the required include file is not installed on my Fedora 33 system. Here is my investigation into this:

The commands
ls /usr/include/llvm/ExecutionEngine/Orc | grep 'Taget'
Results in the following output:

JITTargetMachineBuilder.h
OrcRemoteTargetClient.h
OrcRemoteTargetRPCAPI.h
OrcRemoteTargetServer.h

The command
sudo dnf install llvm-devel
Results in …
Nothing to do.

The command
dnf info llvm | grep Version
results in
Version 11.0.0

#4

There is only llvm-12 have TargetProcessControl.h file. and you can install llvm-12 or find correct tutorial match with llvm-11.x in this

The code file in this:

#5

Thanks.

The easiest thing for me to do was
git checkout release/11.x
and then copy the Kaleidoscope directory to my testing directory.

Once I did that, I get to the following result for toy.kal (using my installed version of llvm):

/toy < toy.kal
ready> ready> Read function definition:define double @fib(double %x) {
entry:
  %cmptmp = fcmp ult double %x, 3.000000e+00
  br i1 %cmptmp, label %ifcont, label %else

else:                                             ; preds = %entry
  %subtmp = fadd double %x, -1.000000e+00
  %calltmp = call double @fib(double %subtmp)
  %subtmp1 = fadd double %x, -2.000000e+00
  %calltmp2 = call double @fib(double %subtmp1)
  %addtmp = fadd double %calltmp, %calltmp2
  br label %ifcont

ifcont:                                           ; preds = %entry, %else
  %iftmp = phi double [ %addtmp, %else ], [ 1.000000e+00, %entry ]
  ret double %iftmp
}

ready> Evaluated to 102334155.000000
#6

I notice the following in the Kaleidoscope 11.x source code

static std::unique_ptr<legacy::FunctionPassManager> TheFPM;

Does legacy this mean that this class has been deprecated and one should use a different one going forward ?

#7

I have another quesiton about this example. It uses the Function class defined by the following include in toy.cpp:

#include "llvm/IR/Function.h`"

and used as a codegen return value; e.g.

  Function *codegen();

When I search for the documentaiotn for this class I do not find it, not even in the doxygen. Looking in llvm/IR/Function.h I do not see documentation there either. Is this class part of the llvm API and if so, where can I find documentation for what will be supported by future releases ?

#8

Yes, LegacyPassManager was the default pass manager. I think LLVM now switches to NewPassManager. And in the last week, Sjoerd Meijer announced that in this mailing thread. Some documentation is available here: Writing an LLVM Pass — LLVM 12 documentation or you can try llvm-tutor which show creating passes with both PassManagers.

Kaleidoscope codegen documented here:
https://llvm.org/docs/tutorial/MyFirstLanguageFrontend/LangImpl03.html#code-generation-setup

Function and Value class are documentaed here:
https://llvm.org/docs/ProgrammersManual.html#the-function-class
https://llvm.org/docs/ProgrammersManual.html#the-value-class

With every new release of LLVM, a release note is also publish which mentions significant changes to LLVM APIs.

For LLVM 11.0.0 Release it is here.
https://releases.llvm.org/11.0.0/docs/ReleaseNotes.html

#9

My further posts to this discussion were suddenly removed as spam and I do not know why or how to recover them.

#10

Maybe you were at trust level 0, few things you can’t do, like sending more than two hyperlinks in a post, more than 10 replies etc.

To remove these restrictions you need to reach at trust level 1 by…

  • Entering at least 5 topics
  • Reading at least 30 posts
  • Spend a total of 10 minutes reading posts