[llvm-c] Expose debug support for LLJIT in Orc bindings

Author: weliveindetail

llvm/include/llvm-c/LLJIT.h

@@ -242,6 +242,12 @@ LLVMOrcIRTransformLayerRef LLVMOrcLLJITGetIRTransformLayer(LLVMOrcLLJITRef J);
  */
 const char *LLVMOrcLLJITGetDataLayoutStr(LLVMOrcLLJITRef J);
 
+/**
+ * Install the plugin that submits debug objects to the executor. Executors must
+ * expose the llvm_orc_registerJITLoaderGDBWrapper symbol.
+ */
+LLVMErrorRef LLVMOrcLLJITEnableDebugSupport(LLVMOrcLLJITRef J);
+
 /**
  * @}
  */

llvm/lib/ExecutionEngine/Orc/Debugging/DebuggerSupport.cpp

@@ -39,7 +39,7 @@ Error enableDebuggerSupport(LLJIT &J) {
     if (!Registrar)
       return Registrar.takeError();
     ObjLinkingLayer->addPlugin(std::make_unique<DebugObjectManagerPlugin>(
-        ES, std::move(*Registrar), true, true));
+        ES, std::move(*Registrar), false, true));
     return Error::success();
   }
   case Triple::MachO: {

llvm/lib/ExecutionEngine/Orc/OrcV2CBindings.cpp

@@ -11,6 +11,7 @@
 #include "llvm-c/OrcEE.h"
 #include "llvm-c/TargetMachine.h"
 
+#include "llvm/ExecutionEngine/Orc/Debugging/DebuggerSupport.h"
 #include "llvm/ExecutionEngine/Orc/JITTargetMachineBuilder.h"
 #include "llvm/ExecutionEngine/Orc/LLJIT.h"
 #include "llvm/ExecutionEngine/Orc/ObjectTransformLayer.h"
@@ -1179,3 +1180,7 @@ void LLVMOrcDisposeLazyCallThroughManager(
     LLVMOrcLazyCallThroughManagerRef LCM) {
   std::unique_ptr<LazyCallThroughManager> TmpLCM(unwrap(LCM));
 }
+
+LLVMErrorRef LLVMOrcLLJITEnableDebugSupport(LLVMOrcLLJITRef J) {
+  return wrap(llvm::orc::enableDebuggerSupport(*unwrap(J)));
+}

llvm/unittests/ExecutionEngine/Orc/CMakeLists.txt

@@ -5,6 +5,7 @@ set(LLVM_LINK_COMPONENTS
   IRReader
   JITLink
   Object
+  OrcDebugging
   OrcJIT
   OrcShared
   OrcTargetProcess

llvm/unittests/ExecutionEngine/Orc/OrcCAPITest.cpp

@@ -494,6 +494,70 @@ TEST_F(OrcCAPITestBase, AddObjectBuffer) {
   ASSERT_TRUE(!!SumAddr);
 }
 
+// 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.
+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;
+}
+}
+
+#if defined(_AIX) or (not defined(__ELF__) and not defined(__MACH__))
+TEST_F(OrcCAPITestBase, DISABLED_EnableDebugSupport) {
+#else
+TEST_F(OrcCAPITestBase, EnableDebugSupport) {
+#endif
+  if (LLVMErrorRef E = LLVMOrcLLJITEnableDebugSupport(Jit))
+    FAIL() << "Error testing LLJIT debug support (triple = " << TargetTriple
+           << "): " << toString(E);
+
+  void *Before = findLastDebugDescriptorEntryPtr();
+  LLVMMemoryBufferRef ObjBuffer = createTestObject(SumExample, "sum.ll");
+  LLVMOrcObjectLayerRef ObjLayer = LLVMOrcLLJITGetObjLinkingLayer(Jit);
+  if (LLVMErrorRef E =
+          LLVMOrcObjectLayerAddObjectFile(ObjLayer, MainDylib, ObjBuffer))
+    FAIL() << "Failed to add object file to ObjLinkingLayer (triple = "
+           << TargetTriple << "): " << toString(E);
+
+  LLVMOrcJITTargetAddress SumAddr;
+  if (LLVMErrorRef E = LLVMOrcLLJITLookup(Jit, &SumAddr, "sum"))
+    FAIL() << "Symbol \"sum\" was not added into JIT (triple = " << TargetTriple
+           << "): " << toString(E);
+
+  void *After = findLastDebugDescriptorEntryPtr();
+  ASSERT_NE(Before, After);
+}
+
 #if defined(_AIX)
 TEST_F(OrcCAPITestBase, DISABLED_ExecutionTest) {
 #else