llvm dev - Nov 2015 - Confused on how to do a machinefunction pass

Thank you so much.
That helped alot.

Fami

On Wed, Nov 4, 2015 at 9:40 AM, John Criswell <jtcriswel at gmail.com>
wrote:
> On 11/3/15 7:54 PM, fateme Hoseini wrote:
>
> Dear John,
> Thank you so much for your help. I looked at those documents. Could you
> kindly answer the following questions:
>
> Does it mean that I have to make my own backend target in order to write a
> machine pass even if I want to run a simple machinefunction pass?  for
> example,if I want my pass to get MIPS instructions as an input, I have to
> copy all the files from mips target and add a file to it which implements
> my pass. and there should be a way to connect the pass to other MIPS
> backend files?
>
>
> No, you do not need to create a new backend.  All you need to do is to add
> your pass to the list of passes that are run when the MIPS code generator
> is used.
>
> In LLVM 3.3, there was a file in the X86 backend that had code to schedule
> all the MachineFunctionPass'es  when the X86 code generator was used. 
That
> was in lib/Target/X86/X86TargetMachine.cpp.  You can probably find a
> similar file for LLVM 3.7 for the MIPS backend.
>
> So, to summarize, you'll add your source file to the MIPS backend, add
a
> line somewhere to run your pass when the MIPS code generator is used, and
> then recompile llvm/lib and llvm/tools/llc.
>
>
>
> As a result, is the way that I described in my first post completely wrong
> because I cannot run a stand alone machine function pass like a frontend
> function pass?
>
>
> As far as I know, there is no way to load a MachineFunctionPass and run it
> using llc, opt, or clang.  I believe you need to compile it into the MIPS
> backend code.
>
>
> Also another question, I'm a PhD student and I'm completely new to
the
> llvm backend process. I want to estimate my project time. How long
> approximately do you think it will take to be get familiar with backend and
> be able to write machinefunction pass? for further steps I have to
> implement a register allocation algorithm.
>
>
> It's difficult to estimate (especially since I haven't implemented
> anything as complicated as a register allocator).  Your profiling pass may
> take anywhere from 1 week to 1 month depending on how complicated it is.  I
> think a register allocator would take anywhere from 1 month up to 6 months
> depending on how robust you need it to be, but since I've never built
one,
> I can't say for certain.
>
> Regards,
>
> John Criswell
>
>
>
> Regards,
> Fami
>
>
> On Tue, Nov 3, 2015 at 3:52 PM, John Criswell <jtcriswel at
gmail.com> wrote:
>
>> Dear Fami,
>>
>> A MachineFunctionPass is run by the code generator, so you can only use
>> it in tools like llc, clang, and libLTO.  The opt program only
manipulates
>> LLVM IR and therefore does not run MachineFunctionPass'es.
>>
>> Regarding documentation, have you looked at the following?
>>
>> http://llvm.org/docs/WritingAnLLVMBackend.html
>> http://llvm.org/docs/CodeGenerator.html
>> http://llvm.org/docs/MIRLangRef.html
>>
>> Regards,
>>
>> John Criswell
>>
>>
>> On 11/3/15 3:47 PM, fateme Hoseini via llvm-dev wrote:
>>
>> Hi everyone,
>> I am a LLVM newbie. I need to write a machinefunction pass for my
>> project. This should be an analyzer of the machine code to do some
>> profiling. I have written a couple of function passes for front end,
but it
>> seems they are completely different. I searched through forum and llvm
>> documents, but couldn't find anything useful or questions were
unanswered.
>> Can anyone reference me to any material on how to do that or help me
with
>> my roblem.
>>
>> I have created a folder in: lib/Transform and put my pass in it.
>> I am writing a simple pass like this:
>>
>> using namespace llvm;
>>
>> namespace {
>>     struct analyzer : public MachineFunctionPass {
>> static char ID;
>> analyzer() : MachineFunctionPass(ID) {}
>> virtual bool runOnMachineFunction(MachineFunction &MF) {
>> errs() << "hello " ;
>> return false;
>> }
>>   };
>> }
>> char analyzer::ID = 0;
>> static RegisterPass<analyzer> X("analyzer", "WAW
analyzer");
>>
>> I make it successfully. But when I load it for my test code I get this
>> error:
>>
>> Pass 'WAW analyzer' is not initialized.
>> Verify if there is a pass dependency cycle.
>> Required Passes:
>> opt: /llvm/llvm-3.7/lib/IR/LegacyPassManager.cpp:635: void
>> llvm::PMTopLevelManager::schedulePass(llvm::Pass*): Assertion `PI
&&
>> "Expected required passes to be initialized"' failed.
>> .....
>>
>> I don't know how to solve it? Do we have to run machinefunction
passes
>> with OPT command? Is this correct to put machinefunction pass in an
>> external folder or do we have to change some llvm built-in files?
>>
>> Regards,
>> Fami
>>
>>
>>
>> _______________________________________________
>> LLVM Developers mailing listllvm-dev at
lists.llvm.orghttp://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>>
>>
>> --
>> John Criswell
>> Assistant Professor
>> Department of Computer Science, University of
Rochesterhttp://www.cs.rochester.edu/u/criswell
>>
>>
>
>
> --
> John Criswell
> Assistant Professor
> Department of Computer Science, University of
Rochesterhttp://www.cs.rochester.edu/u/criswell
>
>
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Hi
So I m trying to write my first backend pass. I created a file in
target\x86\wawanalyzer.cpp based on hexagonHardwareLoops.cpp file. Now it's
just a simple file that prints hello to the output. I have attached the
file to this post.

Then I did the following:

1. add "FunctionPass *createwawAnalyzer();" line to x86.h
2. add file name to CMakelist.txt.
3. This is going to run after postRAscheduler and before code emission so I
changed the x86TrgetMachine.cpp as follow:
void X86PassConfig::addPreEmitPass() {
/////////////add mypass here///////
  addPass(createwawAnalyzer());
//////////////////////////////////
  if (getOptLevel() != CodeGenOpt::None)
    addPass(createExecutionDependencyFixPass(&X86::VR128RegClass));

  if (UseVZeroUpper)
    addPass(createX86IssueVZeroUpperPass());

  if (getOptLevel() != CodeGenOpt::None) {
    addPass(createX86PadShortFunctions());
    addPass(createX86FixupLEAs());
  }
then I run make on mypass and remake  llvm3.7\lib and llvm3.7\tool\llc.
but when I run llc -help it doesn't show my pass. Did I miss some steps or
did something wrong? What's the correct way to run the pass with llc
command?

I appreciate any help,
Regards
Fami

On Wed, Nov 4, 2015 at 1:02 PM, fateme Hoseini <hoseini.f at gmail.com>
wrote:
> Thank you so much.
> That helped alot.
>
> Fami
>
> On Wed, Nov 4, 2015 at 9:40 AM, John Criswell <jtcriswel at
gmail.com> wrote:
>
>> On 11/3/15 7:54 PM, fateme Hoseini wrote:
>>
>> Dear John,
>> Thank you so much for your help. I looked at those documents. Could you
>> kindly answer the following questions:
>>
>> Does it mean that I have to make my own backend target in order to
write
>> a machine pass even if I want to run a simple machinefunction pass? 
for
>> example,if I want my pass to get MIPS instructions as an input, I have
to
>> copy all the files from mips target and add a file to it which
implements
>> my pass. and there should be a way to connect the pass to other MIPS
>> backend files?
>>
>>
>> No, you do not need to create a new backend.  All you need to do is to
>> add your pass to the list of passes that are run when the MIPS code
>> generator is used.
>>
>> In LLVM 3.3, there was a file in the X86 backend that had code to
>> schedule all the MachineFunctionPass'es  when the X86 code
generator was
>> used.  That was in lib/Target/X86/X86TargetMachine.cpp.  You can
probably
>> find a similar file for LLVM 3.7 for the MIPS backend.
>>
>> So, to summarize, you'll add your source file to the MIPS backend,
add a
>> line somewhere to run your pass when the MIPS code generator is used,
and
>> then recompile llvm/lib and llvm/tools/llc.
>>
>>
>>
>> As a result, is the way that I described in my first post completely
>> wrong because I cannot run a stand alone machine function pass like a
>> frontend function pass?
>>
>>
>> As far as I know, there is no way to load a MachineFunctionPass and run
>> it using llc, opt, or clang.  I believe you need to compile it into the
>> MIPS backend code.
>>
>>
>> Also another question, I'm a PhD student and I'm completely new
to the
>> llvm backend process. I want to estimate my project time. How long
>> approximately do you think it will take to be get familiar with backend
and
>> be able to write machinefunction pass? for further steps I have to
>> implement a register allocation algorithm.
>>
>>
>> It's difficult to estimate (especially since I haven't
implemented
>> anything as complicated as a register allocator).  Your profiling pass
may
>> take anywhere from 1 week to 1 month depending on how complicated it
is.  I
>> think a register allocator would take anywhere from 1 month up to 6
months
>> depending on how robust you need it to be, but since I've never
built one,
>> I can't say for certain.
>>
>> Regards,
>>
>> John Criswell
>>
>>
>>
>> Regards,
>> Fami
>>
>>
>> On Tue, Nov 3, 2015 at 3:52 PM, John Criswell <jtcriswel at
gmail.com>
>> wrote:
>>
>>> Dear Fami,
>>>
>>> A MachineFunctionPass is run by the code generator, so you can only
use
>>> it in tools like llc, clang, and libLTO.  The opt program only
manipulates
>>> LLVM IR and therefore does not run MachineFunctionPass'es.
>>>
>>> Regarding documentation, have you looked at the following?
>>>
>>> http://llvm.org/docs/WritingAnLLVMBackend.html
>>> http://llvm.org/docs/CodeGenerator.html
>>> http://llvm.org/docs/MIRLangRef.html
>>>
>>> Regards,
>>>
>>> John Criswell
>>>
>>>
>>> On 11/3/15 3:47 PM, fateme Hoseini via llvm-dev wrote:
>>>
>>> Hi everyone,
>>> I am a LLVM newbie. I need to write a machinefunction pass for my
>>> project. This should be an analyzer of the machine code to do some
>>> profiling. I have written a couple of function passes for front
end, but it
>>> seems they are completely different. I searched through forum and
llvm
>>> documents, but couldn't find anything useful or questions were
unanswered.
>>> Can anyone reference me to any material on how to do that or help
me with
>>> my roblem.
>>>
>>> I have created a folder in: lib/Transform and put my pass in it.
>>> I am writing a simple pass like this:
>>>
>>> using namespace llvm;
>>>
>>> namespace {
>>>     struct analyzer : public MachineFunctionPass {
>>> static char ID;
>>> analyzer() : MachineFunctionPass(ID) {}
>>> virtual bool runOnMachineFunction(MachineFunction &MF) {
>>> errs() << "hello " ;
>>> return false;
>>> }
>>>   };
>>> }
>>> char analyzer::ID = 0;
>>> static RegisterPass<analyzer> X("analyzer",
"WAW analyzer");
>>>
>>> I make it successfully. But when I load it for my test code I get
this
>>> error:
>>>
>>> Pass 'WAW analyzer' is not initialized.
>>> Verify if there is a pass dependency cycle.
>>> Required Passes:
>>> opt: /llvm/llvm-3.7/lib/IR/LegacyPassManager.cpp:635: void
>>> llvm::PMTopLevelManager::schedulePass(llvm::Pass*): Assertion `PI
&&
>>> "Expected required passes to be initialized"' failed.
>>> .....
>>>
>>> I don't know how to solve it? Do we have to run machinefunction
passes
>>> with OPT command? Is this correct to put machinefunction pass in an
>>> external folder or do we have to change some llvm built-in files?
>>>
>>> Regards,
>>> Fami
>>>
>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing listllvm-dev at
lists.llvm.orghttp://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>>>
>>>
>>> --
>>> John Criswell
>>> Assistant Professor
>>> Department of Computer Science, University of
Rochesterhttp://www.cs.rochester.edu/u/criswell
>>>
>>>
>>
>>
>> --
>> John Criswell
>> Assistant Professor
>> Department of Computer Science, University of
Rochesterhttp://www.cs.rochester.edu/u/criswell
>>
>>
>
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On 11/6/2015 9:56 AM, fateme Hoseini via llvm-dev wrote:
>
> then I run make on mypass and remake  llvm3.7\lib and llvm3.7\tool\llc.
> but when I run llc -help it doesn't show my pass. Did I miss some steps
> or did something wrong? What's the correct way to run the pass with llc
> command?
You cannot run individual passes from llc.  Llc -help only shows the 
available command-line options.

Try compiling some .ll file with the llc.  You should see the message 
that your pass it printing.

-Krzysztof

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, 
hosted by The Linux Foundation

Hi,
So, I run my pass in X86 target with llc command and it printed out
"hello****". Now I am trying to do the same pass for ARM target. So I
did
exactly what I did for X86 as mentioned in my previous posts. When I run
the following command:
llc -march=arm test.ll -o test
nothing prints out. I did the same for MIPS target too and I got no result.
Can anyone tell me what I'm doing wrong. Is there any difference between
writing machinefunction passes in x86 and other targets?
Thank you,
Fami

On Fri, Nov 6, 2015 at 10:56 AM, fateme Hoseini <hoseini.f at gmail.com>
wrote:
> Hi
> So I m trying to write my first backend pass. I created a file in
> target\x86\wawanalyzer.cpp based on hexagonHardwareLoops.cpp file. Now
it's
> just a simple file that prints hello to the output. I have attached the
> file to this post.
>
> Then I did the following:
>
> 1. add "FunctionPass *createwawAnalyzer();" line to x86.h
> 2. add file name to CMakelist.txt.
> 3. This is going to run after postRAscheduler and before code emission so
> I changed the x86TrgetMachine.cpp as follow:
> void X86PassConfig::addPreEmitPass() {
> /////////////add mypass here///////
>   addPass(createwawAnalyzer());
> //////////////////////////////////
>   if (getOptLevel() != CodeGenOpt::None)
>     addPass(createExecutionDependencyFixPass(&X86::VR128RegClass));
>
>   if (UseVZeroUpper)
>     addPass(createX86IssueVZeroUpperPass());
>
>   if (getOptLevel() != CodeGenOpt::None) {
>     addPass(createX86PadShortFunctions());
>     addPass(createX86FixupLEAs());
>   }
> then I run make on mypass and remake  llvm3.7\lib and llvm3.7\tool\llc.
> but when I run llc -help it doesn't show my pass. Did I miss some steps
or
> did something wrong? What's the correct way to run the pass with llc
> command?
>
> I appreciate any help,
> Regards
> Fami
>
> On Wed, Nov 4, 2015 at 1:02 PM, fateme Hoseini <hoseini.f at
gmail.com>
> wrote:
>
>> Thank you so much.
>> That helped alot.
>>
>> Fami
>>
>> On Wed, Nov 4, 2015 at 9:40 AM, John Criswell <jtcriswel at
gmail.com>
>> wrote:
>>
>>> On 11/3/15 7:54 PM, fateme Hoseini wrote:
>>>
>>> Dear John,
>>> Thank you so much for your help. I looked at those documents. Could
you
>>> kindly answer the following questions:
>>>
>>> Does it mean that I have to make my own backend target in order to
write
>>> a machine pass even if I want to run a simple machinefunction pass?
for
>>> example,if I want my pass to get MIPS instructions as an input, I
have to
>>> copy all the files from mips target and add a file to it which
implements
>>> my pass. and there should be a way to connect the pass to other
MIPS
>>> backend files?
>>>
>>>
>>> No, you do not need to create a new backend.  All you need to do is
to
>>> add your pass to the list of passes that are run when the MIPS code
>>> generator is used.
>>>
>>> In LLVM 3.3, there was a file in the X86 backend that had code to
>>> schedule all the MachineFunctionPass'es  when the X86 code
generator was
>>> used.  That was in lib/Target/X86/X86TargetMachine.cpp.  You can
probably
>>> find a similar file for LLVM 3.7 for the MIPS backend.
>>>
>>> So, to summarize, you'll add your source file to the MIPS
backend, add a
>>> line somewhere to run your pass when the MIPS code generator is
used, and
>>> then recompile llvm/lib and llvm/tools/llc.
>>>
>>>
>>>
>>> As a result, is the way that I described in my first post
completely
>>> wrong because I cannot run a stand alone machine function pass like
a
>>> frontend function pass?
>>>
>>>
>>> As far as I know, there is no way to load a MachineFunctionPass and
run
>>> it using llc, opt, or clang.  I believe you need to compile it into
the
>>> MIPS backend code.
>>>
>>>
>>> Also another question, I'm a PhD student and I'm completely
new to the
>>> llvm backend process. I want to estimate my project time. How long
>>> approximately do you think it will take to be get familiar with
backend and
>>> be able to write machinefunction pass? for further steps I have to
>>> implement a register allocation algorithm.
>>>
>>>
>>> It's difficult to estimate (especially since I haven't
implemented
>>> anything as complicated as a register allocator).  Your profiling
pass may
>>> take anywhere from 1 week to 1 month depending on how complicated
it is.  I
>>> think a register allocator would take anywhere from 1 month up to 6
months
>>> depending on how robust you need it to be, but since I've never
built one,
>>> I can't say for certain.
>>>
>>> Regards,
>>>
>>> John Criswell
>>>
>>>
>>>
>>> Regards,
>>> Fami
>>>
>>>
>>> On Tue, Nov 3, 2015 at 3:52 PM, John Criswell <jtcriswel at
gmail.com>
>>> wrote:
>>>
>>>> Dear Fami,
>>>>
>>>> A MachineFunctionPass is run by the code generator, so you can
only use
>>>> it in tools like llc, clang, and libLTO.  The opt program only
manipulates
>>>> LLVM IR and therefore does not run MachineFunctionPass'es.
>>>>
>>>> Regarding documentation, have you looked at the following?
>>>>
>>>> http://llvm.org/docs/WritingAnLLVMBackend.html
>>>> http://llvm.org/docs/CodeGenerator.html
>>>> http://llvm.org/docs/MIRLangRef.html
>>>>
>>>> Regards,
>>>>
>>>> John Criswell
>>>>
>>>>
>>>> On 11/3/15 3:47 PM, fateme Hoseini via llvm-dev wrote:
>>>>
>>>> Hi everyone,
>>>> I am a LLVM newbie. I need to write a machinefunction pass for
my
>>>> project. This should be an analyzer of the machine code to do
some
>>>> profiling. I have written a couple of function passes for front
end, but it
>>>> seems they are completely different. I searched through forum
and llvm
>>>> documents, but couldn't find anything useful or questions
were unanswered.
>>>> Can anyone reference me to any material on how to do that or
help me with
>>>> my roblem.
>>>>
>>>> I have created a folder in: lib/Transform and put my pass in
it.
>>>> I am writing a simple pass like this:
>>>>
>>>> using namespace llvm;
>>>>
>>>> namespace {
>>>>     struct analyzer : public MachineFunctionPass {
>>>> static char ID;
>>>> analyzer() : MachineFunctionPass(ID) {}
>>>> virtual bool runOnMachineFunction(MachineFunction &MF) {
>>>> errs() << "hello " ;
>>>> return false;
>>>> }
>>>>   };
>>>> }
>>>> char analyzer::ID = 0;
>>>> static RegisterPass<analyzer> X("analyzer",
"WAW analyzer");
>>>>
>>>> I make it successfully. But when I load it for my test code I
get this
>>>> error:
>>>>
>>>> Pass 'WAW analyzer' is not initialized.
>>>> Verify if there is a pass dependency cycle.
>>>> Required Passes:
>>>> opt: /llvm/llvm-3.7/lib/IR/LegacyPassManager.cpp:635: void
>>>> llvm::PMTopLevelManager::schedulePass(llvm::Pass*): Assertion
`PI &&
>>>> "Expected required passes to be initialized"'
failed.
>>>> .....
>>>>
>>>> I don't know how to solve it? Do we have to run
machinefunction passes
>>>> with OPT command? Is this correct to put machinefunction pass
in an
>>>> external folder or do we have to change some llvm built-in
files?
>>>>
>>>> Regards,
>>>> Fami
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> LLVM Developers mailing listllvm-dev at
lists.llvm.orghttp://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>
>>>>
>>>>
>>>> --
>>>> John Criswell
>>>> Assistant Professor
>>>> Department of Computer Science, University of
Rochesterhttp://www.cs.rochester.edu/u/criswell
>>>>
>>>>
>>>
>>>
>>> --
>>> John Criswell
>>> Assistant Professor
>>> Department of Computer Science, University of
Rochesterhttp://www.cs.rochester.edu/u/criswell
>>>
>>>
>>
>
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