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//===--------- LLJITRemovableCode.cpp -- LLJIT with Code Removal ----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// In this example we will use an the resource management APIs to transfer
// ownership of modules, remove modules from a JITDylib, and then a whole
// JITDylib from the ExecutionSession.
//
//===----------------------------------------------------------------------===//
#include "llvm/ExecutionEngine/Orc/LLJIT.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/Pass.h"
#include "llvm/Support/InitLLVM.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Scalar.h"
#include "../ExampleModules.h"
using namespace llvm;
using namespace llvm::orc;
ExitOnError ExitOnErr;
// Example IR modules.
//
// We will use a few modules containing no-op functions to demonstrate the code
// removal APIs.
const llvm::StringRef FooMod =
R"(
define void @foo() {
entry:
ret void
}
)";
const llvm::StringRef BarMod =
R"(
define void @bar() {
entry:
ret void
}
)";
const llvm::StringRef BazMod =
R"(
define void @baz() {
entry:
ret void
}
)";
int main(int argc, char *argv[]) {
// Initialize LLVM.
InitLLVM X(argc, argv);
InitializeNativeTarget();
InitializeNativeTargetAsmPrinter();
ExitOnErr.setBanner(std::string(argv[0]) + ": ");
// (1) Create LLJIT instance.
auto J = ExitOnErr(LLJITBuilder().create());
// (2) Create a new JITDylib to use for this example.
auto &JD = ExitOnErr(J->createJITDylib("JD"));
// (3) Add the 'foo' module with no explicit resource tracker. The resources
// for 'foo' will be tracked by the default tracker for JD. We will not be
// able to free it separately, but its resources will still be freed when we
// clear or remove JD.
ExitOnErr(J->addIRModule(JD, ExitOnErr(parseExampleModule(FooMod, "foo"))));
// (4) Create a tracker for the module 'bar' and use it to add that module.
auto BarRT = JD.createResourceTracker();
ExitOnErr(
J->addIRModule(BarRT, ExitOnErr(parseExampleModule(BarMod, "bar"))));
// (5) Create a tracker for the module 'baz' and use it to add that module.
auto BazRT = JD.createResourceTracker();
ExitOnErr(
J->addIRModule(BazRT, ExitOnErr(parseExampleModule(BazMod, "baz"))));
// (6) Print out the symbols in their initial state:
auto PrintSymbol = [&](StringRef Name) {
dbgs() << Name << " = ";
if (auto Sym = J->lookup(JD, Name))
dbgs() << *Sym;
else
dbgs() << "error: " << toString(Sym.takeError()) << "\n";
};
dbgs() << "Initially:\n";
PrintSymbol("foo");
PrintSymbol("bar");
PrintSymbol("baz");
// (7) Reset BazRT. This will implicitly transfer tracking of module baz to
// JD's default resource tracker.
dbgs() << "After implicitly transferring ownership of baz to JD's default "
"tracker:\n";
BazRT = nullptr;
PrintSymbol("foo");
PrintSymbol("bar");
PrintSymbol("baz");
// (8) Remove BarRT. This should remove the bar symbol.
dbgs() << "After removing bar (lookup for bar should yield a missing symbol "
"error):\n";
ExitOnErr(BarRT->remove());
PrintSymbol("foo");
PrintSymbol("bar");
PrintSymbol("baz");
// (9) Clear JD. This should remove all symbols currently in the JITDylib.
dbgs() << "After clearing JD (lookup should yield missing symbol errors for "
"all symbols):\n";
ExitOnErr(JD.clear());
PrintSymbol("foo");
PrintSymbol("bar");
PrintSymbol("baz");
// (10) Remove JD from the ExecutionSession. JD can no longer be used.
dbgs() << "Removing JD.\n";
ExitOnErr(J->getExecutionSession().removeJITDylib(JD));
dbgs() << "done.\n";
return 0;
}
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