[LoongArch64] Initial DFEATURE_EMULATE_SINGLESTEP for LA64. (#105741)

Author: LuckyXu-HF

src/coreclr/clrdefinitions.cmake

@@ -28,6 +28,8 @@ if (CLR_CMAKE_TARGET_UNIX)
     add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:UNIX_ARM_ABI>)
   elseif (CLR_CMAKE_TARGET_ARCH_I386)
     add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:UNIX_X86_ABI>)
+  elseif (CLR_CMAKE_TARGET_ARCH_LOONGARCH64)
+    add_definitions(-DFEATURE_EMULATE_SINGLESTEP)
   endif()
 
 endif(CLR_CMAKE_TARGET_UNIX)

src/coreclr/debug/ee/controller.cpp

@@ -3202,7 +3202,7 @@ void DebuggerController::ApplyTraceFlag(Thread *thread)
     g_pEEInterface->MarkThreadForDebugStepping(thread, true);
     LOG((LF_CORDB,LL_INFO1000, "DC::ApplyTraceFlag marked thread for debug stepping\n"));
 
-    SetSSFlag(reinterpret_cast<DT_CONTEXT *>(context) ARM_ARG(thread) ARM64_ARG(thread) RISCV64_ARG(thread));
+    SetSSFlag(reinterpret_cast<DT_CONTEXT *>(context) ARM_ARG(thread) ARM64_ARG(thread) RISCV64_ARG(thread) LOONGARCH64_ARG(thread));
 }
 
 //
@@ -3239,7 +3239,7 @@ void DebuggerController::UnapplyTraceFlag(Thread *thread)
 
     // Always need to unmark for stepping
     g_pEEInterface->MarkThreadForDebugStepping(thread, false);
-    UnsetSSFlag(reinterpret_cast<DT_CONTEXT *>(context) ARM_ARG(thread) ARM64_ARG(thread) RISCV64_ARG(thread));
+    UnsetSSFlag(reinterpret_cast<DT_CONTEXT *>(context) ARM_ARG(thread) ARM64_ARG(thread) RISCV64_ARG(thread) LOONGARCH64_ARG(thread));
 }
 
 void DebuggerController::EnableExceptionHook()

src/coreclr/debug/ee/debugger.cpp

@@ -15890,7 +15890,7 @@ BOOL Debugger::IsThreadContextInvalid(Thread *pThread, CONTEXT *pCtx)
     if (success)
     {
         // Check single-step flag
-        if (IsSSFlagEnabled(reinterpret_cast<DT_CONTEXT *>(pCtx) ARM_ARG(pThread) ARM64_ARG(pThread) RISCV64_ARG(pThread)))
+        if (IsSSFlagEnabled(reinterpret_cast<DT_CONTEXT *>(pCtx) ARM_ARG(pThread) ARM64_ARG(pThread) RISCV64_ARG(pThread) LOONGARCH64_ARG(pThread)))
         {
             // Can't hijack a thread whose SS-flag is set. This could lead to races
             // with the thread taking the SS-exception.

src/coreclr/debug/ee/loongarch64/primitives.cpp

@@ -10,3 +10,25 @@ void CopyREGDISPLAY(REGDISPLAY* pDst, REGDISPLAY* pSrc)
     CONTEXT tmp;
     CopyRegDisplay(pSrc, pDst, &tmp);
 }
+
+void SetSSFlag(DT_CONTEXT *, Thread *pThread)
+{
+    _ASSERTE(pThread != NULL);
+
+    pThread->EnableSingleStep();
+}
+
+void UnsetSSFlag(DT_CONTEXT *, Thread *pThread)
+{
+    _ASSERTE(pThread != NULL);
+
+    pThread->DisableSingleStep();
+}
+
+// Check if single stepping is enabled.
+bool IsSSFlagEnabled(DT_CONTEXT *, Thread *pThread)
+{
+    _ASSERTE(pThread != NULL);
+
+    return pThread->IsSingleStepEnabled();
+}

src/coreclr/debug/inc/loongarch64/primitives.h

@@ -219,24 +219,15 @@ inline bool AddressIsBreakpoint(CORDB_ADDRESS_TYPE* address)
     return CORDbgGetInstruction(address) == CORDbg_BREAK_INSTRUCTION;
 }
 
-inline void SetSSFlag(DT_CONTEXT *pContext)
-{
-    // TODO-LoongArch64: LoongArch64 doesn't support cpsr.
-    _ASSERTE(!"unimplemented on LOONGARCH64 yet");
-}
+class Thread;
+// Enable single stepping.
+void SetSSFlag(DT_CONTEXT *pCtx, Thread *pThread);
 
-inline void UnsetSSFlag(DT_CONTEXT *pContext)
-{
-    // TODO-LoongArch64: LoongArch64 doesn't support cpsr.
-    _ASSERTE(!"unimplemented on LOONGARCH64 yet");
-}
+// Disable single stepping
+void UnsetSSFlag(DT_CONTEXT *pCtx, Thread *pThread);
 
-inline bool IsSSFlagEnabled(DT_CONTEXT * pContext)
-{
-    // TODO-LoongArch64: LoongArch64 doesn't support cpsr.
-    _ASSERTE(!"unimplemented on LOONGARCH64 yet");
-    return false;
-}
+// Check if single stepping is enabled.
+bool IsSSFlagEnabled(DT_CONTEXT *pCtx, Thread *pThread);
 
 
 inline bool PRDIsEqual(PRD_TYPE p1, PRD_TYPE p2)

src/coreclr/vm/CMakeLists.txt

@@ -842,6 +842,7 @@ elseif(CLR_CMAKE_TARGET_ARCH_LOONGARCH64)
 
     set(VM_SOURCES_WKS_ARCH
         ${ARCH_SOURCES_DIR}/profiler.cpp
+        ${ARCH_SOURCES_DIR}/singlestepper.cpp
         gcinfodecoder.cpp
     )
 elseif(CLR_CMAKE_TARGET_ARCH_RISCV64)