196 lines · cpp
1//===- LLJITWithExecutorProcessControl.cpp - LLJIT example with EPC utils -===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// In this example we will use the lazy re-exports utility to lazily compile10// IR modules. We will do this in seven steps:11//12// 1. Create an LLJIT instance.13// 2. Install a transform so that we can see what is being compiled.14// 3. Create an indirect stubs manager and lazy call-through manager.15// 4. Add two modules that will be conditionally compiled, plus a main module.16// 5. Add lazy-rexports of the symbols in the conditionally compiled modules.17// 6. Dump the ExecutionSession state to see the symbol table prior to18// executing any code.19// 7. Verify that only modules containing executed code are compiled.20//21//===----------------------------------------------------------------------===//22 23#include "llvm/ADT/StringMap.h"24#include "llvm/ExecutionEngine/JITLink/JITLinkMemoryManager.h"25#include "llvm/ExecutionEngine/Orc/EPCIndirectionUtils.h"26#include "llvm/ExecutionEngine/Orc/ExecutorProcessControl.h"27#include "llvm/ExecutionEngine/Orc/LLJIT.h"28#include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"29#include "llvm/ExecutionEngine/Orc/OrcABISupport.h"30#include "llvm/ExecutionEngine/Orc/SelfExecutorProcessControl.h"31#include "llvm/Support/InitLLVM.h"32#include "llvm/Support/TargetSelect.h"33#include "llvm/Support/raw_ostream.h"34 35#include "../ExampleModules.h"36 37#include <future>38 39using namespace llvm;40using namespace llvm::orc;41 42ExitOnError ExitOnErr;43 44// Example IR modules.45//46// Note that in the conditionally compiled modules, FooMod and BarMod, functions47// have been given an _body suffix. This is to ensure that their names do not48// clash with their lazy-reexports.49// For clients who do not wish to rename function bodies (e.g. because they want50// to re-use cached objects between static and JIT compiles) techniques exist to51// avoid renaming. See the lazy-reexports section of the ORCv2 design doc.52 53const llvm::StringRef FooMod =54 R"(55 declare i32 @return1()56 57 define i32 @foo_body() {58 entry:59 %0 = call i32 @return1()60 ret i32 %061 }62)";63 64const llvm::StringRef BarMod =65 R"(66 declare i32 @return2()67 68 define i32 @bar_body() {69 entry:70 %0 = call i32 @return2()71 ret i32 %072 }73)";74 75const llvm::StringRef MainMod =76 R"(77 78 define i32 @entry(i32 %argc) {79 entry:80 %and = and i32 %argc, 181 %tobool = icmp eq i32 %and, 082 br i1 %tobool, label %if.end, label %if.then83 84 if.then: ; preds = %entry85 %call = tail call i32 @foo() #286 br label %return87 88 if.end: ; preds = %entry89 %call1 = tail call i32 @bar() #290 br label %return91 92 return: ; preds = %if.end, %if.then93 %retval.0 = phi i32 [ %call, %if.then ], [ %call1, %if.end ]94 ret i32 %retval.095 }96 97 declare i32 @foo()98 declare i32 @bar()99)";100 101extern "C" int32_t return1() { return 1; }102extern "C" int32_t return2() { return 2; }103 104static void *reenter(void *Ctx, void *TrampolineAddr) {105 std::promise<void *> LandingAddressP;106 auto LandingAddressF = LandingAddressP.get_future();107 108 auto *EPCIU = static_cast<EPCIndirectionUtils *>(Ctx);109 EPCIU->getLazyCallThroughManager().resolveTrampolineLandingAddress(110 ExecutorAddr::fromPtr(TrampolineAddr), [&](ExecutorAddr LandingAddress) {111 LandingAddressP.set_value(LandingAddress.toPtr<void *>());112 });113 return LandingAddressF.get();114}115 116static void reportErrorAndExit() {117 errs() << "Unable to lazily compile function. Exiting.\n";118 exit(1);119}120 121static cl::list<std::string> InputArgv(cl::Positional,122 cl::desc("<program arguments>..."));123 124int main(int argc, char *argv[]) {125 // Initialize LLVM.126 InitLLVM X(argc, argv);127 128 InitializeNativeTarget();129 InitializeNativeTargetAsmPrinter();130 131 cl::ParseCommandLineOptions(argc, argv, "LLJITWithLazyReexports");132 ExitOnErr.setBanner(std::string(argv[0]) + ": ");133 134 // (1) Create LLJIT instance.135 auto EPC = ExitOnErr(SelfExecutorProcessControl::Create());136 auto J = ExitOnErr(137 LLJITBuilder().setExecutorProcessControl(std::move(EPC)).create());138 139 // (2) Install transform to print modules as they are compiled:140 J->getIRTransformLayer().setTransform(141 [](ThreadSafeModule TSM,142 const MaterializationResponsibility &R) -> Expected<ThreadSafeModule> {143 TSM.withModuleDo([](Module &M) { dbgs() << "---Compiling---\n" << M; });144 return std::move(TSM); // Not a redundant move: fix build on gcc-7.5145 });146 147 // (3) Create stubs and call-through managers:148 auto EPCIU = ExitOnErr(EPCIndirectionUtils::Create(J->getExecutionSession()));149 ExitOnErr(EPCIU->writeResolverBlock(ExecutorAddr::fromPtr(&reenter),150 ExecutorAddr::fromPtr(EPCIU.get())));151 EPCIU->createLazyCallThroughManager(152 J->getExecutionSession(), ExecutorAddr::fromPtr(&reportErrorAndExit));153 auto ISM = EPCIU->createIndirectStubsManager();154 155 // (4) Add modules.156 ExitOnErr(J->addIRModule(ExitOnErr(parseExampleModule(FooMod, "foo-mod"))));157 ExitOnErr(J->addIRModule(ExitOnErr(parseExampleModule(BarMod, "bar-mod"))));158 ExitOnErr(J->addIRModule(ExitOnErr(parseExampleModule(MainMod, "main-mod"))));159 160 // (5) Add lazy reexports.161 MangleAndInterner Mangle(J->getExecutionSession(), J->getDataLayout());162 SymbolAliasMap ReExports(163 {{Mangle("foo"),164 {Mangle("foo_body"),165 JITSymbolFlags::Exported | JITSymbolFlags::Callable}},166 {Mangle("bar"),167 {Mangle("bar_body"),168 JITSymbolFlags::Exported | JITSymbolFlags::Callable}}});169 ExitOnErr(J->getMainJITDylib().define(170 lazyReexports(EPCIU->getLazyCallThroughManager(), *ISM,171 J->getMainJITDylib(), std::move(ReExports))));172 173 // (6) Dump the ExecutionSession state.174 dbgs() << "---Session state---\n";175 J->getExecutionSession().dump(dbgs());176 dbgs() << "\n";177 178 // (7) Execute the JIT'd main function and pass the example's command line179 // arguments unmodified. This should cause either ExampleMod1 or ExampleMod2180 // to be compiled, and either "1" or "2" returned depending on the number of181 // arguments passed.182 183 // Look up the JIT'd function, cast it to a function pointer, then call it.184 auto EntryAddr = ExitOnErr(J->lookup("entry"));185 auto *Entry = EntryAddr.toPtr<int(int)>();186 187 int Result = Entry(argc);188 outs() << "---Result---\n"189 << "entry(" << argc << ") = " << Result << "\n";190 191 // Destroy the EPCIndirectionUtils utility.192 ExitOnErr(EPCIU->cleanup());193 194 return 0;195}196