C++ Function::Materialize方法代码示例

    bool _runOnFunction(llvm::Function& f) {
        Timer _t2("(sum)");
        Timer _t("initializing");
        initialize();
        _t.split("overhead");

        // f.dump();

        llvm::Module* cur_module = f.getParent();

#if LLVMREV < 217548
        llvm::PassManager fake_pm;
#else
        llvm::legacy::PassManager fake_pm;
#endif
        llvm::InlineCostAnalysis* cost_analysis = new llvm::InlineCostAnalysis();
        fake_pm.add(cost_analysis);
        // llvm::errs() << "doing fake run\n";
        fake_pm.run(*fake_module);
        // llvm::errs() << "done with fake run\n";

        bool did_any_inlining = false;

        // TODO I haven't gotten the callgraph-updating part of the inliner to work,
        // so it's not easy to tell what callsites have been inlined into (ie added to)
        // the function.
        // One simple-but-not-great way to handle it is to just iterate over the entire function
        // multiple times and re-inline things until we don't want to inline any more;
        // NPASSES controls the maximum number of times to attempt that.
        // Right now we actually don't need that, since we only inline fully-optimized
        // functions (from the stdlib), and those will already have had inlining
        // applied recursively.
        const int NPASSES = 1;
        for (int passnum = 0; passnum < NPASSES; passnum++) {
            _t.split("collecting calls");

            std::vector<llvm::CallSite> calls;
            for (llvm::inst_iterator I = llvm::inst_begin(f), E = llvm::inst_end(f); I != E; ++I) {
                llvm::CallInst* call = llvm::dyn_cast<llvm::CallInst>(&(*I));
                // From Inliner.cpp:
                if (!call || llvm::isa<llvm::IntrinsicInst>(call))
                    continue;
                // I->dump();
                llvm::CallSite CS(call);

                llvm::Value* v = CS.getCalledValue();
                llvm::ConstantExpr* ce = llvm::dyn_cast<llvm::ConstantExpr>(v);
                if (!ce)
                    continue;

                assert(ce->isCast());
                llvm::ConstantInt* l_addr = llvm::cast<llvm::ConstantInt>(ce->getOperand(0));
                int64_t addr = l_addr->getSExtValue();

                if (addr == (int64_t)printf)
                    continue;
                llvm::Function* f = g.func_addr_registry.getLLVMFuncAtAddress((void*)addr);
                if (f == NULL) {
                    if (VERBOSITY()) {
                        printf("Giving up on inlining %s:\n",
                               g.func_addr_registry.getFuncNameAtAddress((void*)addr, true).c_str());
                        call->dump();
                    }
                    continue;
                }

                // We load the bitcode lazily, so check if we haven't yet fully loaded the function:
                if (f->isMaterializable()) {
#if LLVMREV < 220600
                    f->Materialize();
#else
                    f->materialize();
#endif
                }

                // It could still be a declaration, though I think the code won't generate this case any more:
                if (f->isDeclaration())
                    continue;

                // Keep this section as a release_assert since the code-to-be-inlined, as well as the inlining
                // decisions, can be different in release mode:
                int op_idx = -1;
                for (llvm::Argument& arg : f->args()) {
                    ++op_idx;
                    llvm::Type* op_type = call->getOperand(op_idx)->getType();
                    if (arg.getType() != op_type) {
                        llvm::errs() << f->getName() << " has arg " << op_idx << " mismatched!\n";
                        llvm::errs() << "Given ";
                        op_type->dump();
                        llvm::errs() << " but underlying function expected ";
                        arg.getType()->dump();
                        llvm::errs() << '\n';
                    }
                    RELEASE_ASSERT(arg.getType() == call->getOperand(op_idx)->getType(), "");
                }

                assert(!f->isDeclaration());
                CS.setCalledFunction(f);
                calls.push_back(CS);
            }
//.........这里部分代码省略.........