[ORC] Remove the automagic Main JITDylib fram ExecutionSession.

This patch removes the magic "main" JITDylib from ExecutionEngine. The main
JITDylib was created automatically at ExecutionSession construction time, and
all subsequently created JITDylibs were added to the main JITDylib's
links-against list by default. This saves a couple of lines of boilerplate for
simple JIT setups, but this isn't worth introducing magical behavior for.

ORCv2 clients should now construct their own main JITDylib using
ExecutionSession::createJITDylib and set up its linkages manually using
JITDylib::setSearchOrder (or related methods in JITDylib).

3 files changed, 26 insertions, 22 deletions

diff --git a/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter1/KaleidoscopeJIT.h b/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter1/KaleidoscopeJIT.h
index a7fa3afc470..020b72c2394 100644
--- a/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter1/KaleidoscopeJIT.h
+++ b/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter1/KaleidoscopeJIT.h
@@ -39,14 +39,17 @@ private:
   MangleAndInterner Mangle;
   ThreadSafeContext Ctx;
 
+  JITDylib &MainJD;
+
 public:
   KaleidoscopeJIT(JITTargetMachineBuilder JTMB, DataLayout DL)
       : ObjectLayer(ES,
                     []() { return std::make_unique<SectionMemoryManager>(); }),
         CompileLayer(ES, ObjectLayer, ConcurrentIRCompiler(std::move(JTMB))),
         DL(std::move(DL)), Mangle(ES, this->DL),
-        Ctx(std::make_unique<LLVMContext>()) {
-    ES.getMainJITDylib().addGenerator(
+        Ctx(std::make_unique<LLVMContext>()),
+        MainJD(ES.createJITDylib("<main>")) {
+    MainJD.addGenerator(
         cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
             DL.getGlobalPrefix())));
   }
@@ -69,12 +72,11 @@ public:
   LLVMContext &getContext() { return *Ctx.getContext(); }
 
   Error addModule(std::unique_ptr<Module> M) {
-    return CompileLayer.add(ES.getMainJITDylib(),
-                            ThreadSafeModule(std::move(M), Ctx));
+    return CompileLayer.add(MainJD, ThreadSafeModule(std::move(M), Ctx));
   }
 
   Expected<JITEvaluatedSymbol> lookup(StringRef Name) {
-    return ES.lookup({&ES.getMainJITDylib()}, Mangle(Name.str()));
+    return ES.lookup({&MainJD}, Mangle(Name.str()));
   }
 };
 
diff --git a/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter2/KaleidoscopeJIT.h b/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter2/KaleidoscopeJIT.h
index e9999efd37a..8037e58ae4f 100644
--- a/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter2/KaleidoscopeJIT.h
+++ b/llvm/examples/Kaleidoscope/BuildingAJIT/Chapter2/KaleidoscopeJIT.h
@@ -45,15 +45,17 @@ private:
   MangleAndInterner Mangle;
   ThreadSafeContext Ctx;
 
+  JITDylib &MainJD;
+
 public:
   KaleidoscopeJIT(JITTargetMachineBuilder JTMB, DataLayout DL)
       : ObjectLayer(ES,
                     []() { return std::make_unique<SectionMemoryManager>(); }),
         CompileLayer(ES, ObjectLayer, ConcurrentIRCompiler(std::move(JTMB))),
-        OptimizeLayer(ES, CompileLayer, optimizeModule),
-        DL(std::move(DL)), Mangle(ES, this->DL),
-        Ctx(std::make_unique<LLVMContext>()) {
-    ES.getMainJITDylib().addGenerator(
+        OptimizeLayer(ES, CompileLayer, optimizeModule), DL(std::move(DL)),
+        Mangle(ES, this->DL), Ctx(std::make_unique<LLVMContext>()),
+        MainJD(ES.createJITDylib("<main>")) {
+    MainJD.addGenerator(
         cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
             DL.getGlobalPrefix())));
   }
@@ -76,12 +78,11 @@ public:
   }
 
   Error addModule(std::unique_ptr<Module> M) {
-    return OptimizeLayer.add(ES.getMainJITDylib(),
-                             ThreadSafeModule(std::move(M), Ctx));
+    return OptimizeLayer.add(MainJD, ThreadSafeModule(std::move(M), Ctx));
   }
 
   Expected<JITEvaluatedSymbol> lookup(StringRef Name) {
-    return ES.lookup({&ES.getMainJITDylib()}, Mangle(Name.str()));
+    return ES.lookup({&MainJD}, Mangle(Name.str()));
   }
 
 private:
diff --git a/llvm/examples/SpeculativeJIT/SpeculativeJIT.cpp b/llvm/examples/SpeculativeJIT/SpeculativeJIT.cpp
index 5a0ad376bcd..f4cfb7403db 100644
--- a/llvm/examples/SpeculativeJIT/SpeculativeJIT.cpp
+++ b/llvm/examples/SpeculativeJIT/SpeculativeJIT.cpp
@@ -76,12 +76,12 @@ public:
 
   ExecutionSession &getES() { return *ES; }
 
-  Error addModule(JITDylib &JD, ThreadSafeModule TSM) {
-    return CODLayer.add(JD, std::move(TSM));
+  Error addModule(ThreadSafeModule TSM) {
+    return CODLayer.add(MainJD, std::move(TSM));
   }
 
   Expected<JITEvaluatedSymbol> lookup(StringRef UnmangledName) {
-    return ES->lookup({&ES->getMainJITDylib()}, Mangle(UnmangledName));
+    return ES->lookup({&MainJD}, Mangle(UnmangledName));
   }
 
   ~SpeculativeJIT() { CompileThreads.wait(); }
@@ -101,15 +101,15 @@ private:
       std::unique_ptr<LazyCallThroughManager> LCTMgr,
       IndirectStubsManagerBuilderFunction ISMBuilder,
       std::unique_ptr<DynamicLibrarySearchGenerator> ProcessSymbolsGenerator)
-      : ES(std::move(ES)), DL(std::move(DL)), LCTMgr(std::move(LCTMgr)),
+      : ES(std::move(ES)), DL(std::move(DL)),
+        MainJD(this->ES->createJITDylib("<main>")), LCTMgr(std::move(LCTMgr)),
         CompileLayer(*this->ES, ObjLayer,
                      ConcurrentIRCompiler(std::move(JTMB))),
         S(Imps, *this->ES),
         SpeculateLayer(*this->ES, CompileLayer, S, Mangle, BlockFreqQuery()),
         CODLayer(*this->ES, SpeculateLayer, *this->LCTMgr,
                  std::move(ISMBuilder)) {
-    this->ES->getMainJITDylib().addGenerator(
-        std::move(ProcessSymbolsGenerator));
+    MainJD.addGenerator(std::move(ProcessSymbolsGenerator));
     this->CODLayer.setImplMap(&Imps);
     this->ES->setDispatchMaterialization(
 
@@ -119,9 +119,9 @@ private:
           auto Work = [SharedMU, &JD]() { SharedMU->doMaterialize(JD); };
           CompileThreads.async(std::move(Work));
         });
-    ExitOnErr(S.addSpeculationRuntime(this->ES->getMainJITDylib(), Mangle));
+    ExitOnErr(S.addSpeculationRuntime(MainJD, Mangle));
     LocalCXXRuntimeOverrides CXXRuntimeoverrides;
-    ExitOnErr(CXXRuntimeoverrides.enable(this->ES->getMainJITDylib(), Mangle));
+    ExitOnErr(CXXRuntimeoverrides.enable(MainJD, Mangle));
   }
 
   static std::unique_ptr<SectionMemoryManager> createMemMgr() {
@@ -133,6 +133,8 @@ private:
   MangleAndInterner Mangle{*ES, DL};
   ThreadPool CompileThreads{NumThreads};
 
+  JITDylib &MainJD;
+
   Triple TT;
   std::unique_ptr<LazyCallThroughManager> LCTMgr;
   IRCompileLayer CompileLayer;
@@ -172,8 +174,7 @@ int main(int argc, char *argv[]) {
       return 1;
     }
 
-    ExitOnErr(SJ->addModule(SJ->getES().getMainJITDylib(),
-                            ThreadSafeModule(std::move(M), std::move(Ctx))));
+    ExitOnErr(SJ->addModule(ThreadSafeModule(std::move(M), std::move(Ctx))));
   }
 
   auto MainSym = ExitOnErr(SJ->lookup("main"));