Revisit advanced LLJIT examples and tests

llvm/examples/OrcV2Examples/LLJITWithRemoteDebugging/CMakeLists.txt

@@ -3,6 +3,7 @@ set(LLVM_LINK_COMPONENTS
   ExecutionEngine
   IRReader
   JITLink
+  OrcDebugging
   OrcJIT
   OrcShared
   OrcTargetProcess

llvm/examples/OrcV2Examples/LLJITWithRemoteDebugging/LLJITWithRemoteDebugging.cpp

@@ -77,6 +77,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ExecutionEngine/Orc/Debugging/DebuggerSupport.h"
 #include "llvm/ExecutionEngine/Orc/JITTargetMachineBuilder.h"
 #include "llvm/ExecutionEngine/Orc/LLJIT.h"
 #include "llvm/ExecutionEngine/Orc/ObjectLinkingLayer.h"
@@ -174,32 +175,13 @@ int main(int argc, char *argv[]) {
     TSMs.push_back(ExitOnErr(parseExampleModuleFromFile(Path)));
   }
 
-  std::string TT;
-  StringRef MainModuleName;
-  TSMs.front().withModuleDo([&MainModuleName, &TT](Module &M) {
-    MainModuleName = M.getName();
-    TT = M.getTargetTriple();
-    if (TT.empty())
-      TT = sys::getProcessTriple();
-  });
-
-  // Create a target machine that matches the input triple.
-  JITTargetMachineBuilder JTMB((Triple(TT)));
-  JTMB.setCodeModel(CodeModel::Small);
-  JTMB.setRelocationModel(Reloc::PIC_);
-
   // Create LLJIT and destroy it before disconnecting the target process.
   outs() << "Initializing LLJIT for remote executor\n";
-  auto J = ExitOnErr(LLJITBuilder()
-                          .setExecutorProcessControl(std::move(EPC))
-                          .setJITTargetMachineBuilder(std::move(JTMB))
-                          .setObjectLinkingLayerCreator([&](auto &ES, const auto &TT) {
-                            return std::make_unique<ObjectLinkingLayer>(ES);
-                          })
-                          .create());
+  auto J = ExitOnErr(
+      LLJITBuilder().setExecutorProcessControl(std::move(EPC)).create());
 
   // Add plugin for debug support.
-  ExitOnErr(addDebugSupport(J->getObjLinkingLayer()));
+  ExitOnErr(enableDebuggerSupport(*J));
 
   // Load required shared libraries on the remote target and add a generator
   // for each of it, so the compiler can lookup their symbols.

llvm/examples/OrcV2Examples/LLJITWithRemoteDebugging/RemoteJITUtils.cpp

@@ -27,22 +27,6 @@
 using namespace llvm;
 using namespace llvm::orc;
 
-Error addDebugSupport(ObjectLayer &ObjLayer) {
-  ExecutionSession &ES = ObjLayer.getExecutionSession();
-  auto Registrar = createJITLoaderGDBRegistrar(ES);
-  if (!Registrar)
-    return Registrar.takeError();
-
-  auto *ObjLinkingLayer = cast<ObjectLinkingLayer>(&ObjLayer);
-  if (!ObjLinkingLayer)
-    return createStringError(inconvertibleErrorCode(),
-                             "No debug support for given object layer type");
-
-  ObjLinkingLayer->addPlugin(std::make_unique<DebugObjectManagerPlugin>(
-      ES, std::move(*Registrar), true, true));
-  return Error::success();
-}
-
 Expected<std::unique_ptr<DefinitionGenerator>>
 loadDylib(ExecutionSession &ES, StringRef RemotePath) {
   if (auto Handle = ES.getExecutorProcessControl().loadDylib(RemotePath.data()))
@@ -111,11 +95,15 @@ launchLocalExecutor(StringRef ExecutablePath) {
     close(FromExecutor[ReadEnd]);
 
     // Execute the child process.
-    std::unique_ptr<char[]> ExecPath, FDSpecifier;
+    std::unique_ptr<char[]> ExecPath, FDSpecifier, TestOutputFlag;
     {
       ExecPath = std::make_unique<char[]>(ExecutablePath.size() + 1);
       strcpy(ExecPath.get(), ExecutablePath.data());
 
+      const char *TestOutputFlagStr = "test-jitloadergdb";
+      TestOutputFlag = std::make_unique<char[]>(strlen(TestOutputFlagStr) + 1);
+      strcpy(TestOutputFlag.get(), TestOutputFlagStr);
+
       std::string FDSpecifierStr("filedescs=");
       FDSpecifierStr += utostr(ToExecutor[ReadEnd]);
       FDSpecifierStr += ',';
@@ -124,7 +112,8 @@ launchLocalExecutor(StringRef ExecutablePath) {
       strcpy(FDSpecifier.get(), FDSpecifierStr.c_str());
     }
 
-    char *const Args[] = {ExecPath.get(), FDSpecifier.get(), nullptr};
+    char *const Args[] = {ExecPath.get(), TestOutputFlag.get(),
+                          FDSpecifier.get(), nullptr};
     int RC = execvp(ExecPath.get(), Args);
     if (RC != 0)
       return make_error<StringError>(

llvm/examples/OrcV2Examples/LLJITWithRemoteDebugging/RemoteJITUtils.h

@@ -36,8 +36,6 @@ launchLocalExecutor(llvm::StringRef ExecutablePath);
 llvm::Expected<std::unique_ptr<llvm::orc::SimpleRemoteEPC>>
 connectTCPSocket(llvm::StringRef NetworkAddress);
 
-llvm::Error addDebugSupport(llvm::orc::ObjectLayer &ObjLayer);
-
 llvm::Expected<std::unique_ptr<llvm::orc::DefinitionGenerator>>
 loadDylib(llvm::orc::ExecutionSession &ES, llvm::StringRef RemotePath);
 

llvm/test/Examples/OrcV2Examples/Inputs/argc_sub1.ll

@@ -0,0 +1,16 @@
+define i32 @sub1(i32 %0) {
+  %2 = add i32 %0, -1
+  ret i32 %2
+}
+
+define i32 @main(i32 %0) {
+  %2 = call i32 @sub1(i32 %0)
+  ret i32 %2
+}
+
+!llvm.module.flags = !{!0}
+!llvm.dbg.cu = !{!1}
+
+!0 = !{i32 2, !"Debug Info Version", i32 3}
+!1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang 18.0.0git", emissionKind: FullDebug)
+!2 = !DIFile(filename: "argc_sub1.c", directory: ".")

llvm/test/Examples/OrcV2Examples/lljit-with-remote-debugging.test

@@ -1,15 +1,21 @@
-# This test makes sure that the example builds and executes as expected.
+# Check that the debug support plugin appends a jit_code_entry to the
+# jit_descriptor of the child process.
+
 # Instructions for debugging can be found in LLJITWithRemoteDebugging.cpp
 
 # REQUIRES: default_triple
 # UNSUPPORTED: target=powerpc64{{.*}}
 
-# RUN: LLJITWithRemoteDebugging %p/Inputs/argc_sub1_elf.ll | FileCheck --check-prefix=CHECK0 %s
-# CHECK0: Parsing input IR code from: {{.*}}/Inputs/argc_sub1_elf.ll
+# RUN: LLJITWithRemoteDebugging %p/Inputs/argc_sub1.ll 2>&1 | FileCheck --check-prefix=CHECK0 %s
+# CHECK0: __jit_debug_descriptor.last_entry = [[BEFORE0:0x[0-9a-f]+]]
+# CHECK0-NOT: __jit_debug_descriptor.last_entry = [[BEFORE0]]
+# CHECK0: Parsing input IR code from: {{.*}}/Inputs/argc_sub1.ll
 # CHECK0: Running: main()
 # CHECK0: Exit code: 0
 
-# RUN: LLJITWithRemoteDebugging %p/Inputs/argc_sub1_elf.ll --args 2nd 3rd 4th | FileCheck --check-prefix=CHECK3 %s
-# CHECK3: Parsing input IR code from: {{.*}}/Inputs/argc_sub1_elf.ll
+# RUN: LLJITWithRemoteDebugging %p/Inputs/argc_sub1.ll --args 2nd 3rd 4th 2>&1 | FileCheck --check-prefix=CHECK3 %s
+# CHECK3: __jit_debug_descriptor.last_entry = [[BEFORE3:0x[0-9a-f]+]]
+# CHECK3-NOT: __jit_debug_descriptor.last_entry = [[BEFORE3]]
+# CHECK3: Parsing input IR code from: {{.*}}/Inputs/argc_sub1.ll
 # CHECK3: Running: main("2nd", "3rd", "4th")
 # CHECK3: Exit code: 3

llvm/tools/llvm-jitlink/llvm-jitlink-executor/llvm-jitlink-executor.cpp

@@ -112,6 +112,44 @@ int openListener(std::string Host, std::string PortStr) {
 #endif // LLVM_ON_UNIX
 }
 
+// This must be kept in sync with gdb/gdb/jit.h .
+extern "C" {
+
+typedef enum {
+  JIT_NOACTION = 0,
+  JIT_REGISTER_FN,
+  JIT_UNREGISTER_FN
+} jit_actions_t;
+
+struct jit_code_entry {
+  struct jit_code_entry *next_entry;
+  struct jit_code_entry *prev_entry;
+  const char *symfile_addr;
+  uint64_t symfile_size;
+};
+
+struct jit_descriptor {
+  uint32_t version;
+  // This should be jit_actions_t, but we want to be specific about the
+  // bit-width.
+  uint32_t action_flag;
+  struct jit_code_entry *relevant_entry;
+  struct jit_code_entry *first_entry;
+};
+
+// We put information about the JITed function in this global, which the
+// debugger reads.  Make sure to specify the version statically, because the
+// debugger checks the version before we can set it during runtime.
+extern struct jit_descriptor __jit_debug_descriptor;
+
+static void *findLastDebugDescriptorEntryPtr() {
+  struct jit_code_entry *Last = __jit_debug_descriptor.first_entry;
+  while (Last && Last->next_entry)
+    Last = Last->next_entry;
+  return Last;
+}
+}
+
 int main(int argc, char *argv[]) {
 #if LLVM_ENABLE_THREADS
 
@@ -121,10 +159,11 @@ int main(int argc, char *argv[]) {
   int InFD = 0;
   int OutFD = 0;
 
+  std::vector<StringRef> TestOutputFlags;
+
   if (argc < 2)
     printErrorAndExit("insufficient arguments");
   else {
-
     StringRef ConnectArg = argv[FirstProgramArg++];
 #ifndef NDEBUG
     if (ConnectArg == "debug") {
@@ -133,6 +172,11 @@ int main(int argc, char *argv[]) {
     }
 #endif
 
+    while (ConnectArg.starts_with("test-")) {
+      TestOutputFlags.push_back(ConnectArg);
+      ConnectArg = argv[FirstProgramArg++];
+    }
+
     StringRef SpecifierType, Specifier;
     std::tie(SpecifierType, Specifier) = ConnectArg.split('=');
     if (SpecifierType == "filedescs") {
@@ -156,6 +200,10 @@ int main(int argc, char *argv[]) {
       printErrorAndExit("invalid specifier type \"" + SpecifierType + "\"");
   }
 
+  if (llvm::is_contained(TestOutputFlags, "test-jitloadergdb"))
+    fprintf(stderr, "__jit_debug_descriptor.last_entry = 0x%016" PRIx64 "\n",
+            pointerToJITTargetAddress(findLastDebugDescriptorEntryPtr()));
+
   auto Server =
       ExitOnErr(SimpleRemoteEPCServer::Create<FDSimpleRemoteEPCTransport>(
           [](SimpleRemoteEPCServer::Setup &S) -> Error {
@@ -173,6 +221,11 @@ int main(int argc, char *argv[]) {
           InFD, OutFD));
 
   ExitOnErr(Server->waitForDisconnect());
+
+  if (llvm::is_contained(TestOutputFlags, "test-jitloadergdb"))
+    fprintf(stderr, "__jit_debug_descriptor.last_entry = 0x%016" PRIx64 "\n",
+            pointerToJITTargetAddress(findLastDebugDescriptorEntryPtr()));
+
   return 0;
 
 #else