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//===-- addFuncEntryCallPass.cpp - Optimize druntime calls ----------------===//
//
// LDC – the LLVM D compiler
//
// This file is distributed under the University of Illinois Open Source
// License. See the LICENSE file for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Pass.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Passes/PassBuilder.h"
#include "llvm/Passes/PassPlugin.h"
using namespace llvm;
namespace {
class FuncEntryCallPass : public FunctionPass {
Value *funcToCallUponEntry = nullptr;
public:
static char ID;
FuncEntryCallPass() : FunctionPass(ID) {}
bool doInitialization(Module &M) override;
bool runOnFunction(Function &F) override;
};
}
char FuncEntryCallPass::ID = 0;
bool FuncEntryCallPass::doInitialization(Module &M) {
// Add fwd declaration of the `void __test_funcentrycall(void)` function.
auto functionType = FunctionType::get(Type::getVoidTy(M.getContext()), false);
funcToCallUponEntry =
M.getOrInsertFunction("__test_funcentrycall", functionType).getCallee();
return true;
}
bool FuncEntryCallPass::runOnFunction(Function &F) {
// Add call to `__test_funcentrycall(void)` at the start of _every_ function
// (this includes e.g. `ldc.register_dso`!)
llvm::BasicBlock &block = F.getEntryBlock();
IRBuilder<> builder(&block, block.begin());
builder.CreateCall(FunctionCallee(cast<Function>(funcToCallUponEntry)));
return true;
}
namespace {
struct MyPass : public PassInfoMixin<MyPass> {
// The first argument of the run() function defines on what level
// of granularity your pass will run (e.g. Module, Function).
// The second argument is the corresponding AnalysisManager
// (e.g ModuleAnalysisManager, FunctionAnalysisManager)
PreservedAnalyses run(Module &M, ModuleAnalysisManager &MAM) {
FuncEntryCallPass pass;
pass.doInitialization(M);
for (Function &F : M.functions()) {
if (!F.isDeclaration())
pass.runOnFunction(F);
}
return PreservedAnalyses::none();
}
};
}
// This part is the new way of registering your pass
extern "C" ::llvm::PassPluginLibraryInfo LLVM_ATTRIBUTE_WEAK
llvmGetPassPluginInfo() {
return {
LLVM_PLUGIN_API_VERSION, "MyPass", "v0.1",
[](PassBuilder &PB) {
PB.registerPipelineStartEPCallback(
[](ModulePassManager &mpm, OptimizationLevel) {
mpm.addPass(MyPass());
}
);
}
};
}
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