./bin/opt: unknown pass name 'passname'

Beginners
1

I have installed the llvm from this repository…
git clone --depth=1 GitHub - llvm/llvm-project: The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. Note: the repository does not accept github pull requests at this moment. Please submit your patches at http://reviews.llvm.org.

I want to create a new pass that identifies all implicit invocations of constructors in a C++ program, including the source location, the variable involved and the constructor being invoked. hence I followed this link. Writing an LLVM Pass — LLVM 18.0.0git documentation

I have created a new directory with name : ConstructorPass in /llvm/lib/Transforms

Then I changed the /Transforms/CMakeLists.txt and added add_subdirectory(ConstructorPass)

Then I have created two files at ConstructorPass directory: CMakeLists.txt and ConstructorPass.cpp

Here is the CMakeLists.txt

add_llvm_library( LLVMConstructorPass MODULE
ConstructorPass.cpp
PLUGIN_TOOL
opt
)

Here is the ConstructorPass.cpp
#include “llvm/Pass.h”
#include “llvm/IR/Function.h”
#include “llvm/IR/Module.h”
#include “llvm/IR/Instructions.h”
#include “llvm/Support/raw_ostream.h”

using namespace llvm;

namespace {
struct ConstructorPass : public FunctionPass {
static char ID;
ConstructorPass() : FunctionPass(ID) {}

    bool runOnFunction(Function &F) override {
        //functionality coded here...
        return modified;
    }
};

}

char ConstructorPass::ID = 0;

static RegisterPass X(“constructor-pass”, “Identify implicit invocations of constructors in C++ functions”, false, false);

Then I tried to build the project using

llvm-project/build> cmake -DLLVM_ENABLE_PROJECTS=clang -DCMAKE_BUILD_TYPE=Release -G “Unix Makefiles” …/llvm

Then I have created a file hello.cpp at /llvm/build directory
Then I compiled the hello.cpp as

clang -c -emit-llvm hello.cpp

Then when I try to use the pass that I have created… I got this error…

./bin/opt -load lib/LLVMConstructorPass.so -passes=constructor-pass < hello.bc > /dev/null
./bin/opt: unknown pass name ‘constructor-pass’

This is the version:
llvm-project/build/bin$ llvm-cov --version
Ubuntu LLVM version 14.0.0

Optimized build.
Default target: x86_64-pc-linux-gnu
Host CPU: alderlake

Please help me to fix this issue…

2

You’re trying to use the old pass manager, and not the new. Unfortunately it looks like the documentation you linked wasn’t updated. See this instead