[lli] Add option -lljit-platform=Inactive to disable platform support explicitly

[sgraenitz]

Summary

This option tells LLJIT to disable platform support explicitly: JITDylibs aren't scanned for special init/deinit symbols and no runtime API interposes are injected.
It's useful in two cases: for platforms that don't have such requirements and platforms for which we have no explicit support yet and that don't work well with the generic IR platform.

[sgraenitz]

This can be used to fix test failures on Windows when re-applying D98931

llvm/tools/lli/lli.cpp

242

Inactive appeared to me as a sound term in code. Alternatives like No/None/Disabled/Passive seemed misleading in one or the other context (e.g. setUp__Platform).

For the option value I am uncertain. On the one hand it's always good to keep terms aligned, on the other hand it might be confusing the user. It could also be Off or something else.

What do you think?

[sgraenitz]

Apply MCJIT small code-model tests to ORC in preparation for default JIT engine switch

[lhames]

LGTM. Thanks Stefan!

llvm/include/llvm/ExecutionEngine/Orc/LLJIT.h

 ///
 /// MachOPlatform installs an ObjectLinkingLayer plugin to scrape initializers
 /// from the __mod_inits section. It also provides interposes for the dlfcn
 /// functions (dlopen, dlclose, dlsym, dlerror) that work for JITDylibs as
 /// well as regular libraries (JITDylibs will be preferenced, so make sure
 /// your JITDylib names do not shadow any real library paths).
 Error setUpMachOPlatform(LLJIT &J);
 
+/// Configure the LLJIT instance to disable platform support explicitly. This is
+/// useful in two cases: for platforms that don't have such requirements and for
+/// platforms, that we have no explicit support yet and that don't work well
+/// with the generic IR platform.
+Error setUpInactivePlatform(LLJIT &J);
+
 } // End namespace orc
 } // End namespace llvm
 
 #endif // LLVM_EXECUTIONENGINE_ORC_LLJIT_H

llvm/lib/ExecutionEngine/Orc/LLJIT.cpp

 
 /// Generic IR Platform Support
 ///
 /// Scrapes llvm.global_ctors and llvm.global_dtors and replaces them with
 /// specially named 'init' and 'deinit'. Injects definitions / interposes for
 /// some runtime API, including __cxa_atexit, dlopen, and dlclose.
 class GenericLLVMIRPlatformSupport : public LLJIT::PlatformSupport {
 public:
-  // GenericLLVMIRPlatform &P) : P(P) {
   GenericLLVMIRPlatformSupport(LLJIT &J)
       : J(J), InitFunctionPrefix(J.mangle("__orc_init_func.")) {
 
     getExecutionSession().setPlatform(
         std::make_unique<GenericLLVMIRPlatform>(*this));
 
     setInitTransform(J, GlobalCtorDtorScraper(*this, InitFunctionPrefix));
 
private:
   LLJIT &J;
   MachOPlatform &MP;
   DlFcnValues DlFcn;
   ItaniumCXAAtExitSupport AtExitMgr;
   DenseMap<void *, unsigned> JDRefCounts;
   std::map<std::thread::id, std::unique_ptr<std::string>> dlErrorMsgs;
 };
 
+/// Inactive Platform Support
+///
+/// Explicitly disables platform support. JITDylib are not scanned for special
+/// init/deinit symbols. No runtime API interposes are injected.
+class InactivePlatformSupport : public LLJIT::PlatformSupport {
+public:
+  InactivePlatformSupport() = default;
+
+  Error initialize(JITDylib &JD) override {
+    LLVM_DEBUG(dbgs() << "InactivePlatformSupport: no initializers running for "
+                      << JD.getName() << "\n");
+    return Error::success();
+  }
+
+  Error deinitialize(JITDylib &JD) override {
+    LLVM_DEBUG(
+        dbgs() << "InactivePlatformSupport: no deinitializers running for "
+               << JD.getName() << "\n");
+    return Error::success();
+  }
+};
+
 } // end anonymous namespace
 
 namespace llvm {
 namespace orc {
 
 void LLJIT::PlatformSupport::setInitTransform(
     LLJIT &J, IRTransformLayer::TransformFunction T) {
   J.InitHelperTransformLayer->setTransform(std::move(T));
Error setUpMachOPlatform(LLJIT &J) {
   LLVM_DEBUG({ dbgs() << "Setting up MachOPlatform support for LLJIT\n"; });
   auto MP = MachOPlatformSupport::Create(J, J.getMainJITDylib());
   if (!MP)
     return MP.takeError();
   J.setPlatformSupport(std::move(*MP));
   return Error::success();
 }
 
+Error setUpInactivePlatform(LLJIT &J) {
+  LLVM_DEBUG(
+      { dbgs() << "Explicitly deactivated platform support for LLJIT\n"; });
+  J.setPlatformSupport(std::make_unique<InactivePlatformSupport>());
+  return Error::success();
+}
+
 Error LLLazyJITBuilderState::prepareForConstruction() {
   if (auto Err = LLJITBuilderState::prepareForConstruction())
     return Err;
   TT = JTMB->getTargetTriple();
   return Error::success();
 }
 
 Error LLLazyJIT::addLazyIRModule(JITDylib &JD, ThreadSafeModule TSM) {

llvm/test/ExecutionEngine/MCJIT/cross-module-sm-pic-a.ll

-; RUN: %lli -extra-module=%p/Inputs/cross-module-b.ll -relocation-model=pic -code-model=small %s > /dev/null
+; RUN: %lli -jit-kind=mcjit -extra-module=%p/Inputs/cross-module-b.ll -relocation-model=pic -code-model=small %s > /dev/null
+; RUN: %lli -jit-kind=orc -lljit-platform=Inactive -extra-module=%p/Inputs/cross-module-b.ll -relocation-model=pic -code-model=small %s > /dev/null
 ; XFAIL: mips-, mipsel-, i686, i386
 
 declare i32 @FB()
 
 define i32 @FA() {
   ret i32 0
 }
 
 define i32 @main() {
   %r = call i32 @FB( )   ; <i32> [#uses=1]
   ret i32 %r
 }
 

llvm/test/ExecutionEngine/MCJIT/multi-module-sm-pic-a.ll

-; RUN: %lli -extra-module=%p/Inputs/multi-module-b.ll -extra-module=%p/Inputs/multi-module-c.ll -relocation-model=pic -code-model=small %s > /dev/null
+; RUN: %lli -jit-kind=mcjit -extra-module=%p/Inputs/multi-module-b.ll -extra-module=%p/Inputs/multi-module-c.ll -relocation-model=pic -code-model=small %s > /dev/null
+; RUN: %lli -jit-kind=orc -lljit-platform=Inactive -extra-module=%p/Inputs/multi-module-b.ll -extra-module=%p/Inputs/multi-module-c.ll -relocation-model=pic -code-model=small %s > /dev/null
 ; XFAIL: mips-, mipsel-, i686, i386
 
 declare i32 @FB()
 
 define i32 @main() {
   %r = call i32 @FB( )   ; <i32> [#uses=1]
   ret i32 %r
 }
 

llvm/test/ExecutionEngine/MCJIT/test-global-init-nonzero-sm-pic.ll

-; RUN: %lli -relocation-model=pic -code-model=small %s > /dev/null
+; RUN: %lli -jit-kind=mcjit -relocation-model=pic -code-model=small %s > /dev/null
+; RUN: %lli -jit-kind=orc -lljit-platform=Inactive -relocation-model=pic -code-model=small %s > /dev/null
 ; XFAIL: mips-, mipsel-, aarch64, arm, i686, i386
 
 @count = global i32 1, align 4
 
 define i32 @main() nounwind uwtable {
 entry:
   %retval = alloca i32, align 4
   %i = alloca i32, align 4

llvm/test/ExecutionEngine/MCJIT/test-ptr-reloc-sm-pic.ll

-; RUN: %lli -O0 -relocation-model=pic -code-model=small %s
+; RUN: %lli -jit-kind=mcjit -O0 -relocation-model=pic -code-model=small %s
+; RUN: %lli -jit-kind=orc -lljit-platform=Inactive -O0 -relocation-model=pic -code-model=small %s
 ; XFAIL: mips-, mipsel-, aarch64, arm, i686, i386
 
 @.str = private unnamed_addr constant [6 x i8] c"data1\00", align 1
 @ptr = global i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str, i32 0, i32 0), align 4
 @.str1 = private unnamed_addr constant [6 x i8] c"data2\00", align 1
 @ptr2 = global i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str1, i32 0, i32 0), align 4
 
 define i32 @main(i32 %argc, i8** nocapture %argv) nounwind readonly {
 entry:
   %0 = load i8*, i8** @ptr, align 4
   %1 = load i8*, i8** @ptr2, align 4
   %cmp = icmp eq i8* %0, %1
   %. = zext i1 %cmp to i32
   ret i32 %.
 }
 

llvm/tools/lli/lli.cpp

GenerateSoftFloatCalls("soft-float",
     cl::desc("Generate software floating point library calls"),
     cl::init(false));
 
   cl::opt<bool> NoProcessSymbols(
       "no-process-syms",
       cl::desc("Do not resolve lli process symbols in JIT'd code"),
       cl::init(false));
 
-  enum class LLJITPlatform { DetectHost, GenericIR, MachO };
+  enum class LLJITPlatform { Inactive, DetectHost, GenericIR, MachO };
 
   cl::opt<LLJITPlatform>
       Platform("lljit-platform", cl::desc("Platform to use with LLJIT"),
                cl::init(LLJITPlatform::DetectHost),
                cl::values(clEnumValN(LLJITPlatform::DetectHost, "DetectHost",
                                      "Select based on JIT target triple"),
                           clEnumValN(LLJITPlatform::GenericIR, "GenericIR",
                                      "Use LLJITGenericIRPlatform"),
                           clEnumValN(LLJITPlatform::MachO, "MachO",
-                                     "Use LLJITMachOPlatform")),
+                                     "Use LLJITMachOPlatform"),
+                          clEnumValN(LLJITPlatform::Inactive, "Inactive",
+                                     "Disable platform support explicitly")),
                cl::Hidden);
 
   enum class DumpKind {
     NoDump,
     DumpFuncsToStdOut,
     DumpModsToStdOut,
     DumpModsToDisk
   };
// Set up LLJIT platform.
     switch (P) {
     case LLJITPlatform::GenericIR:
       // Nothing to do: LLJITBuilder will use this by default.
       break;
     case LLJITPlatform::MachO:
       Builder.setPlatformSetUp(orc::setUpMachOPlatform);
       ExitOnErr(orc::enableObjCRegistration("libobjc.dylib"));
       break;
+    case LLJITPlatform::Inactive:
+      Builder.setPlatformSetUp(orc::setUpInactivePlatform);
+      break;
     default:
       llvm_unreachable("Unrecognized platform value");
     }
   }
 
   std::unique_ptr<orc::TargetProcessControl> TPC = nullptr;
   if (JITLinker == JITLinkerKind::JITLink) {
     TPC = ExitOnErr(orc::SelfTargetProcessControl::Create(