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2017-Mar-31 06:27 UTC

[llvm-dev] How to write the same things as `opt` command in C++ API

Hi, I'm Ryo Ota. I'm using LLVM 3.8.1. I have a quesion about inlining
function in C++ API.

I'd like to inline some functions in a module in the same way as `opt
-inline` command. But my C++ code didn't work what I want to do.

For example, by using `opt -inline` command,`main.ll` is converted into the
`inlined.ll`(`opt` command worked what I want to do)

[main.ll  (Not inlined)]

; ModuleID = 'my module'

define private i32 @a() {
entry:
  %c = call i32 @c()
  ret i32 %c
}

define private i32 @b() {
entry:
  %a = call i32 @a()
  %b = call i32 @b() ; key-point (infinite-recursive)
  %res = add i32 %a, %b
  ret i32 %res
}

define private i32 @c() {
entry:
  ret i32 2
}

define i32 @main() {
entrypoint:
  %b = call i32 @b()
  ret i32 %b

}



[inlined.ll] Made by `opt-3.8 -S -inline main.ll > inlined.ll` command

define private i32 @b() {
entry:
  %b = call i32 @b()
  %res = add i32 2, %b ; a is inlined. (a == c, c == 2)
  ret i32 %res
}

define i32 @main() {
entrypoint:
  %b = call i32 @b()
  ret i32 %b
}



`opt` command worked what I want to do. But my C++ doesn't work like
`opt` command. The following code is my C++ code, which didn't work I
what to do. My code has `undef`. `inlined.ll` doen't have `undef`.

@main returns @b(). But below code, @main returns undef. I think @b
has a infinite-recursive call. But I don't want it to dump `undef`.
Could you tell me how to stop inlining of `undef`?





[output of C++ doe]

; ModuleID = 'my module'

; Function Attrs: norecurse nounwind readnone
define i32 @main() #0 {
entrypoint:
  ret i32 undef
}

attributes #0 = { norecurse nounwind readnone }



[C++ code]

/// @brief context
llvm::LLVMContext context;
/// @brief module
std::unique_ptr<llvm::Module> module
llvm::make_unique<llvm::Module>("my module", context);

llvm::PassManagerBuilder pm_builder;

llvm::legacy::PassManager pm;

pm_builder.Inliner = llvm::createFunctionInliningPass();

pm_builder.populateModulePassManager(pm);


/// @brief Create function type (void) => i32
llvm::FunctionType       *commonfuncType
llvm::FunctionType::get(llvm::Type::getInt32Ty(context), {}, false);

/// @brief Create a function (define i32 a())
llvm::Function           *aFun     llvm::Function::Create(commonfuncType,
llvm::Function::PrivateLinkage,
"a", module.get());
/// @brief Create a function (define i32 b())
llvm::Function           *bFun     llvm::Function::Create(commonfuncType,
llvm::Function::PrivateLinkage,
"b", module.get());
/// @brief Create a function (define i32 c())
llvm::Function           *cFun     llvm::Function::Create(commonfuncType,
llvm::Function::PrivateLinkage,
"c", module.get());



// Body of the `a` function
{
    /// @brief Set entry label
    llvm::BasicBlock *block = llvm::BasicBlock::Create(context,
"entry", aFun);
    /// @brief builder
    llvm::IRBuilder<> builder(block);
    builder.SetInsertPoint(block);

    llvm::CallInst *cCall = builder.CreateCall(cFun, {}, "c");

    llvm::Value *res = cCall;


    builder.CreateRet(res);
    llvm::verifyFunction(*aFun);
}

// Body of the `b` function
{
    /// @brief Set entry label
    llvm::BasicBlock *block = llvm::BasicBlock::Create(context,
"entry", bFun);
    /// @brief builder
    llvm::IRBuilder<> builder(block);
    builder.SetInsertPoint(block);


    llvm::CallInst *aCall = builder.CreateCall(aFun, {}, "a");
    llvm::CallInst *cCall = builder.CreateCall(bFun, {}, "c");

    llvm::Value *res = builder.CreateAdd(aCall, cCall, "res");


    builder.CreateRet(res);
    llvm::verifyFunction(*bFun);
}

// Body of the `c` function
{
    /// @brief Set entry label
    llvm::BasicBlock *block = llvm::BasicBlock::Create(context,
"entry", cFun);
    /// @brief builder
    llvm::IRBuilder<> builder(block);
    builder.SetInsertPoint(block);


    llvm::Value *res llvm::ConstantInt::get(llvm::Type::getInt32Ty(context), 2);

    builder.CreateRet(res);
    llvm::verifyFunction(*cFun);
}


/// @brief Start of Main function
{
    llvm::FunctionType *const func_type
llvm::FunctionType::get(llvm::Type::getInt32Ty(context), false);
    llvm::Function *const main_func llvm::Function::Create(func_type,
llvm::Function::ExternalLinkage,
"main",
                                                             module.get());
    llvm::BasicBlock *const entry = llvm::BasicBlock::Create(context,
"entrypoint", main_func);
    llvm::IRBuilder<> builder(entry);

    builder.SetInsertPoint(entry);

    llvm::CallInst *bCall = builder.CreateCall(bFun, {}, "b");
    builder.CreateRet(bCall);

    llvm::verifyFunction(*main_func);
}

pm.run(*module);

module->dump();




if you comment-outed `pm.run(*module);` you have the following output.


define private i32 @a() {
entry:
  %c = call i32 @c()
  ret i32 %c
}

define private i32 @b() {
entry:
  %a = call i32 @a()
  %c = call i32 @b()
  %res = add i32 %a, %c
  ret i32 %res
}

define private i32 @c() {
entry:
  ret i32 2
}

define i32 @main() {
entrypoint:
  %b = call i32 @b()
  ret i32 %b
}




Sincerely,
Ryo
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Craig Topper via llvm-dev

2017-Mar-31 06:50 UTC

head link

[llvm-dev] How to write the same things as `opt` command in C++ API

I believe calling pm_builder.populateModulePassManager(pm); will cause a
bunch of passes to be ran as if you had ran 'opt -O2'. What do you get
if
you run 'opt-3.8 -S -O2 main.ll'?

~Craig

On Thu, Mar 30, 2017 at 11:27 PM, via llvm-dev <llvm-dev at
lists.llvm.org>
wrote:
> Hi, I'm Ryo Ota. I'm using LLVM 3.8.1. I have a quesion about
inlining
> function in C++ API.
>
> I'd like to inline some functions in a module in the same way as `opt
> -inline` command. But my C++ code didn't work what I want to do.
>
> For example, by using `opt -inline` command,`main.ll` is converted into
> the `inlined.ll`(`opt` command worked what I want to do)
>
> [main.ll  (Not inlined)]
>
> ; ModuleID = 'my module'
>
> define private i32 @a() {
> entry:
>   %c = call i32 @c()
>   ret i32 %c
> }
>
> define private i32 @b() {
> entry:
>   %a = call i32 @a()
>   %b = call i32 @b() ; key-point (infinite-recursive)
>   %res = add i32 %a, %b
>   ret i32 %res
> }
>
> define private i32 @c() {
> entry:
>   ret i32 2
> }
>
> define i32 @main() {
> entrypoint:
>   %b = call i32 @b()
>   ret i32 %b
>
> }
>
>
>
> [inlined.ll] Made by `opt-3.8 -S -inline main.ll > inlined.ll` command
>
> define private i32 @b() {
> entry:
>   %b = call i32 @b()
>   %res = add i32 2, %b ; a is inlined. (a == c, c == 2)
>   ret i32 %res
> }
>
> define i32 @main() {
> entrypoint:
>   %b = call i32 @b()
>   ret i32 %b
> }
>
>
>
> `opt` command worked what I want to do. But my C++ doesn't work like
`opt` command. The following code is my C++ code, which didn't work I what
to do. My code has `undef`. `inlined.ll` doen't have `undef`.
>
> @main returns @b(). But below code, @main returns undef. I think @b has a
infinite-recursive call. But I don't want it to dump `undef`. Could you tell
me how to stop inlining of `undef`?
>
>
>
>
>
> [output of C++ doe]
>
> ; ModuleID = 'my module'
>
> ; Function Attrs: norecurse nounwind readnone
> define i32 @main() #0 {
> entrypoint:
>   ret i32 undef
> }
>
> attributes #0 = { norecurse nounwind readnone }
>
>
>
> [C++ code]
>
> /// @brief context
> llvm::LLVMContext context;
> /// @brief module
> std::unique_ptr<llvm::Module> module =
llvm::make_unique<llvm::Module>("my module", context);
>
> llvm::PassManagerBuilder pm_builder;
>
> llvm::legacy::PassManager pm;
>
> pm_builder.Inliner = llvm::createFunctionInliningPass();
>
> pm_builder.populateModulePassManager(pm);
>
>
> /// @brief Create function type (void) => i32
> llvm::FunctionType       *commonfuncType =
llvm::FunctionType::get(llvm::Type::getInt32Ty(context), {}, false);
>
> /// @brief Create a function (define i32 a())
> llvm::Function           *aFun     = llvm::Function::Create(commonfuncType,
llvm::Function::PrivateLinkage, "a", module.get());
> /// @brief Create a function (define i32 b())
> llvm::Function           *bFun     = llvm::Function::Create(commonfuncType,
llvm::Function::PrivateLinkage, "b", module.get());
> /// @brief Create a function (define i32 c())
> llvm::Function           *cFun     = llvm::Function::Create(commonfuncType,
llvm::Function::PrivateLinkage, "c", module.get());
>
>
>
> // Body of the `a` function
> {
>     /// @brief Set entry label
>     llvm::BasicBlock *block = llvm::BasicBlock::Create(context,
"entry", aFun);
>     /// @brief builder
>     llvm::IRBuilder<> builder(block);
>     builder.SetInsertPoint(block);
>
>     llvm::CallInst *cCall = builder.CreateCall(cFun, {}, "c");
>
>     llvm::Value *res = cCall;
>
>
>     builder.CreateRet(res);
>     llvm::verifyFunction(*aFun);
> }
>
> // Body of the `b` function
> {
>     /// @brief Set entry label
>     llvm::BasicBlock *block = llvm::BasicBlock::Create(context,
"entry", bFun);
>     /// @brief builder
>     llvm::IRBuilder<> builder(block);
>     builder.SetInsertPoint(block);
>
>
>     llvm::CallInst *aCall = builder.CreateCall(aFun, {}, "a");
>     llvm::CallInst *cCall = builder.CreateCall(bFun, {}, "c");
>
>     llvm::Value *res = builder.CreateAdd(aCall, cCall, "res");
>
>
>     builder.CreateRet(res);
>     llvm::verifyFunction(*bFun);
> }
>
> // Body of the `c` function
> {
>     /// @brief Set entry label
>     llvm::BasicBlock *block = llvm::BasicBlock::Create(context,
"entry", cFun);
>     /// @brief builder
>     llvm::IRBuilder<> builder(block);
>     builder.SetInsertPoint(block);
>
>
>     llvm::Value *res =
llvm::ConstantInt::get(llvm::Type::getInt32Ty(context), 2);
>
>     builder.CreateRet(res);
>     llvm::verifyFunction(*cFun);
> }
>
>
> /// @brief Start of Main function
> {
>     llvm::FunctionType *const func_type =
llvm::FunctionType::get(llvm::Type::getInt32Ty(context), false);
>     llvm::Function *const main_func = llvm::Function::Create(func_type,
llvm::Function::ExternalLinkage, "main",
>                                                              module.get());
>     llvm::BasicBlock *const entry = llvm::BasicBlock::Create(context,
"entrypoint", main_func);
>     llvm::IRBuilder<> builder(entry);
>
>     builder.SetInsertPoint(entry);
>
>     llvm::CallInst *bCall = builder.CreateCall(bFun, {}, "b");
>     builder.CreateRet(bCall);
>
>     llvm::verifyFunction(*main_func);
> }
>
> pm.run(*module);
>
> module->dump();
>
>
>
>
> if you comment-outed `pm.run(*module);` you have the following output.
>
>
> define private i32 @a() {
> entry:
>   %c = call i32 @c()
>   ret i32 %c
> }
>
> define private i32 @b() {
> entry:
>   %a = call i32 @a()
>   %c = call i32 @b()
>   %res = add i32 %a, %c
>   ret i32 %res
> }
>
> define private i32 @c() {
> entry:
>   ret i32 2
> }
>
> define i32 @main() {
> entrypoint:
>   %b = call i32 @b()
>   ret i32 %b
> }
>
>
>
>
> Sincerely,
> Ryo
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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via llvm-dev

2017-Mar-31 06:57 UTC

head link

[llvm-dev] How to write the same things as `opt` command in C++ API

Thank you very much your fast response!
When typed 'opt-3.8 -S -O2 main.ll', I got:

; ModuleID = 'main.ll'


; Function Attrs: norecurse nounwind readnone

define i32 @main() #0 {

entrypoint:

  ret i32 undef

}


attributes #0 = { norecurse nounwind readnone }


This result is the same as my C++ code.

I'm not sure my use of `llvm::legacyPassManeger` and
`llvm::PassManagerBuilder`. To write inlining in C++, I explored in llvm's
Github and other repositories which use LLVM, then I wrote the C++ code.
I'd like to be taught the correct use.



Sincerely,

Ryo




2017年3月31日(金) 15:50 Craig Topper <craig.topper at gmail.com>:
> I believe calling pm_builder.populateModulePassManager(pm); will cause a
> bunch of passes to be ran as if you had ran 'opt -O2'. What do you
get if
> you run 'opt-3.8 -S -O2 main.ll'?
>
> ~Craig
>
> On Thu, Mar 30, 2017 at 11:27 PM, via llvm-dev <llvm-dev at
lists.llvm.org>
> wrote:
>
> Hi, I'm Ryo Ota. I'm using LLVM 3.8.1. I have a quesion about
inlining
> function in C++ API.
>
> I'd like to inline some functions in a module in the same way as `opt
> -inline` command. But my C++ code didn't work what I want to do.
>
> For example, by using `opt -inline` command,`main.ll` is converted into
> the `inlined.ll`(`opt` command worked what I want to do)
>
> [main.ll  (Not inlined)]
>
> ; ModuleID = 'my module'
>
> define private i32 @a() {
> entry:
>   %c = call i32 @c()
>   ret i32 %c
> }
>
> define private i32 @b() {
> entry:
>   %a = call i32 @a()
>   %b = call i32 @b() ; key-point (infinite-recursive)
>   %res = add i32 %a, %b
>   ret i32 %res
> }
>
> define private i32 @c() {
> entry:
>   ret i32 2
> }
>
> define i32 @main() {
> entrypoint:
>   %b = call i32 @b()
>   ret i32 %b
>
> }
>
>
>
> [inlined.ll] Made by `opt-3.8 -S -inline main.ll > inlined.ll` command
>
> define private i32 @b() {
> entry:
>   %b = call i32 @b()
>   %res = add i32 2, %b ; a is inlined. (a == c, c == 2)
>   ret i32 %res
> }
>
> define i32 @main() {
> entrypoint:
>   %b = call i32 @b()
>   ret i32 %b
> }
>
>
>
> `opt` command worked what I want to do. But my C++ doesn't work like
`opt` command. The following code is my C++ code, which didn't work I what
to do. My code has `undef`. `inlined.ll` doen't have `undef`.
>
> @main returns @b(). But below code, @main returns undef. I think @b has a
infinite-recursive call. But I don't want it to dump `undef`. Could you tell
me how to stop inlining of `undef`?
>
>
>
>
>
> [output of C++ doe]
>
> ; ModuleID = 'my module'
>
> ; Function Attrs: norecurse nounwind readnone
> define i32 @main() #0 {
> entrypoint:
>   ret i32 undef
> }
>
> attributes #0 = { norecurse nounwind readnone }
>
>
>
> [C++ code]
>
> /// @brief context
> llvm::LLVMContext context;
> /// @brief module
> std::unique_ptr<llvm::Module> module =
llvm::make_unique<llvm::Module>("my module", context);
>
> llvm::PassManagerBuilder pm_builder;
>
> llvm::legacy::PassManager pm;
>
> pm_builder.Inliner = llvm::createFunctionInliningPass();
>
> pm_builder.populateModulePassManager(pm);
>
>
> /// @brief Create function type (void) => i32
> llvm::FunctionType       *commonfuncType =
llvm::FunctionType::get(llvm::Type::getInt32Ty(context), {}, false);
>
> /// @brief Create a function (define i32 a())
> llvm::Function           *aFun     = llvm::Function::Create(commonfuncType,
llvm::Function::PrivateLinkage, "a", module.get());
> /// @brief Create a function (define i32 b())
> llvm::Function           *bFun     = llvm::Function::Create(commonfuncType,
llvm::Function::PrivateLinkage, "b", module.get());
> /// @brief Create a function (define i32 c())
> llvm::Function           *cFun     = llvm::Function::Create(commonfuncType,
llvm::Function::PrivateLinkage, "c", module.get());
>
>
>
> // Body of the `a` function
> {
>     /// @brief Set entry label
>     llvm::BasicBlock *block = llvm::BasicBlock::Create(context,
"entry", aFun);
>     /// @brief builder
>     llvm::IRBuilder<> builder(block);
>     builder.SetInsertPoint(block);
>
>     llvm::CallInst *cCall = builder.CreateCall(cFun, {}, "c");
>
>     llvm::Value *res = cCall;
>
>
>     builder.CreateRet(res);
>     llvm::verifyFunction(*aFun);
> }
>
> // Body of the `b` function
> {
>     /// @brief Set entry label
>     llvm::BasicBlock *block = llvm::BasicBlock::Create(context,
"entry", bFun);
>     /// @brief builder
>     llvm::IRBuilder<> builder(block);
>     builder.SetInsertPoint(block);
>
>
>     llvm::CallInst *aCall = builder.CreateCall(aFun, {}, "a");
>     llvm::CallInst *cCall = builder.CreateCall(bFun, {}, "c");
>
>     llvm::Value *res = builder.CreateAdd(aCall, cCall, "res");
>
>
>     builder.CreateRet(res);
>     llvm::verifyFunction(*bFun);
> }
>
> // Body of the `c` function
> {
>     /// @brief Set entry label
>     llvm::BasicBlock *block = llvm::BasicBlock::Create(context,
"entry", cFun);
>     /// @brief builder
>     llvm::IRBuilder<> builder(block);
>     builder.SetInsertPoint(block);
>
>
>     llvm::Value *res =
llvm::ConstantInt::get(llvm::Type::getInt32Ty(context), 2);
>
>     builder.CreateRet(res);
>     llvm::verifyFunction(*cFun);
> }
>
>
> /// @brief Start of Main function
> {
>     llvm::FunctionType *const func_type =
llvm::FunctionType::get(llvm::Type::getInt32Ty(context), false);
>     llvm::Function *const main_func = llvm::Function::Create(func_type,
llvm::Function::ExternalLinkage, "main",
>                                                              module.get());
>     llvm::BasicBlock *const entry = llvm::BasicBlock::Create(context,
"entrypoint", main_func);
>     llvm::IRBuilder<> builder(entry);
>
>     builder.SetInsertPoint(entry);
>
>     llvm::CallInst *bCall = builder.CreateCall(bFun, {}, "b");
>     builder.CreateRet(bCall);
>
>     llvm::verifyFunction(*main_func);
> }
>
> pm.run(*module);
>
> module->dump();
>
>
>
>
> if you comment-outed `pm.run(*module);` you have the following output.
>
>
> define private i32 @a() {
> entry:
>   %c = call i32 @c()
>   ret i32 %c
> }
>
> define private i32 @b() {
> entry:
>   %a = call i32 @a()
>   %c = call i32 @b()
>   %res = add i32 %a, %c
>   ret i32 %res
> }
>
> define private i32 @c() {
> entry:
>   ret i32 2
> }
>
> define i32 @main() {
> entrypoint:
>   %b = call i32 @b()
>   ret i32 %b
> }
>
>
>
>
> Sincerely,
> Ryo
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
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