Workflow of LLVM and clang - llvm

Question

I am just a beginner in LLVM, and (https://www.cs.cornell.edu/~asampson/blog/llvm.html) webpage along with the stack overflow, and my fellow researcher has helped me a lot.
I would first like to illustrate what I am trying to work on (the problem) and then I will describe the approach that I have taken to work on the problem.
Then, I need your advice and guidance if I am missing anything.
Work Problem
My input is a C program and output is its SSA form in prefix representation printed in an output File.
For eg, if the C code segment is :
x=4;
x++;
z=x+7;
The output SSA form in prefix representation is :
( = x0 4)
( = x1 (+ x0 1) )
( = z (x1 + 7) )
Please ignore the actual IR instruction for now, just assume that I am able to read the IR and convert it to this form, with some extra statements (which I am not presenting here for readability).
My ignorant Approach of using LLVM (Please find the complete program below)
using namespace llvm;
namespace {
struct TestPass: public ModulePass {
IRssa::ptr ir_ssa = IRssa::ptr(new IRssa());
static char ID;
typedef std::list<std::pair<std::string, std::list<Instruction *> > > funcDump;
TestPass() : ModulePass(ID) { }
std::map<std::string, funcDump> workingList;
bool runOnModule(Module &M) {
std::string funcName, bkName;
for (Function &F : M) { //Found a new Function
if (isa<Function>(F) && !(F.getName().startswith("llvm."))) {
funcName = F.getName();
std::pair<std::string, std::list<Instruction *> > funcBlockList;
std::list<std::pair<std::string, std::list<Instruction *> > > wholeFuncBlocks;
for (BasicBlock &B : F) { //Blocks of the Function
if (isa<BasicBlock>(B)) {
bkName = B.getName();
}
std::list<Instruction *> listInst;
for (auto &I : B) {
Instruction *ins;
ins = &I;
listInst.push_back(ins);
}
funcBlockList.first = bkName;
funcBlockList.second = listInst;
wholeFuncBlocks.push_back(funcBlockList);
}
workingList[funcName] = wholeFuncBlocks;//Mapping of the functions
}
}
ir_ssa->setFunctionDump(workingList);
funcDump funcData;
funcData = workingList["start_program"]; //Starting from the start_program function
convertFunctionToSSA(funcData, ir_ssa);
std::ofstream outFile;
outFile.open("Out.ssa");
printSSA_toFile(outFile, ir_ssa);
return false;
}
};
}
char TestPass::ID = 0;
static RegisterPass<TestPass> X("testPass", "Testing A Pass");
static void registerTestPass(const PassManagerBuilder &, legacy::PassManagerBase &PM) {
PM.add(new TestPass());
}
static RegisterStandardPasses RegisterMyPass(PassManagerBuilder::EP_ModuleOptimizerEarly, registerTestPass);
static RegisterStandardPasses RegisterMyPass0(PassManagerBuilder::EP_EnabledOnOptLevel0, registerTestPass);
//Automatically enable the pass (http://adriansampson.net/blog/clangpass.html)
Description:
As shown above I am calling a runOnModule() and collecting all the IR Instructions of all the blocks for each function in the program into a workingList data structure (a std::map in this case). After all the functions in the given program is finished reading, I then do my required task of reading IR instructions one at a time, function by function and block by block (in the user defined function convertFunctionToSSA(funcData, ir_ssa) taking the whole function IR as argument and the result of processing these IR is returned in the argument ir_ssa). I am also printing the resulted value from ir_ssa onto the output file outFile.
Now How do I Run (I type the following)
clang -O1 -g -Xclang -emit-llvm -c someProgram.c -o test.bc
opt -O1 -instnamer -mem2reg -simplifycfg -loops -lcssa -loop-simplify -loop-rotate -loop-unroll -unroll-count=15 -unroll-allow-partial -load src/libTestPass.so -testPass test.bc -o test
My Expectation
I assume (as per my understanding) that the above two commands does the following.
First clang takes the program someProgram.c and generates IR as an output file "test.bc".
The next command opt, takes the file "test.bc" and then applies all the above passes one by one till the last pass "-unroll-allow-partial" and it also links my library libTestPass.so (this .so file is generated on compiling the above ModulePass program) then, finally the pass "-testPass" which I think is the pass where I am doing my process (of converting to SSA prefix representation).
Your Advice and Comments
I am not sure if LLVM is actually running in the sequence as I am assuming (My Expectation). Kindly comment if I am missing anything or if my assumption is not correct. Also please feel free to ask more details if necessary.
Current Problem Faced
I am able to successfully convert most of the C programs but on a specific program I stuck with some error. Debugging this error lead me to think that I am missing somethink or my assumption about this working of LLVM in regards to the calling order of clang and opt is not correct.
Your help is highly appreciated.