Implement Edit and Continue on Linux and MacOS

src/coreclr/clrdefinitions.cmake

@@ -56,11 +56,9 @@ endif(CLR_CMAKE_HOST_WIN32)
 if (NOT (CLR_CMAKE_TARGET_ARCH_I386 AND CLR_CMAKE_TARGET_UNIX))
   add_compile_definitions(EnC_SUPPORTED)
 endif()
-if(CLR_CMAKE_TARGET_ARCH_AMD64 OR CLR_CMAKE_TARGET_ARCH_I386 OR CLR_CMAKE_TARGET_ARCH_ARM64)
-  if(CLR_CMAKE_TARGET_WIN32)
-    add_compile_definitions(FEATURE_ENC_SUPPORTED)
-  endif(CLR_CMAKE_TARGET_WIN32)
-endif(CLR_CMAKE_TARGET_ARCH_AMD64 OR CLR_CMAKE_TARGET_ARCH_I386 OR CLR_CMAKE_TARGET_ARCH_ARM64)
+if(CLR_CMAKE_TARGET_ARCH_AMD64 OR CLR_CMAKE_TARGET_ARCH_ARM64 OR (CLR_CMAKE_TARGET_ARCH_I386 AND CLR_CMAKE_TARGET_WIN32))
+  add_compile_definitions(FEATURE_ENC_SUPPORTED)
+endif(CLR_CMAKE_TARGET_ARCH_AMD64 OR CLR_CMAKE_TARGET_ARCH_ARM64 OR (CLR_CMAKE_TARGET_ARCH_I386 AND CLR_CMAKE_TARGET_WIN32))
 
 if(CLR_CMAKE_TARGET_WIN32 AND CLR_CMAKE_TARGET_ARCH_AMD64)
 add_compile_definitions(OUT_OF_PROCESS_SETTHREADCONTEXT)

src/coreclr/debug/di/rsthread.cpp

@@ -2135,11 +2135,6 @@ HRESULT CordbThread::InterceptCurrentException(ICorDebugFrame * pFrame)
     FAIL_IF_NEUTERED(this);
     ATT_REQUIRE_STOPPED_MAY_FAIL(GetProcess());
 
-#if defined(FEATURE_DBGIPC_TRANSPORT_DI)
-    // Continuable exceptions are not implemented on Unix-like platforms.
-    return E_NOTIMPL;
-
-#else  // !FEATURE_DBGIPC_TRANSPORT_DI
     HRESULT hr = S_OK;
     EX_TRY
     {
@@ -2216,7 +2211,6 @@ HRESULT CordbThread::InterceptCurrentException(ICorDebugFrame * pFrame)
     }
     EX_CATCH_HRESULT(hr);
     return hr;
-#endif // FEATURE_DBGIPC_TRANSPORT_DI
 }
 
 //---------------------------------------------------------------------------------------

src/coreclr/inc/eetwain.h

@@ -332,7 +332,7 @@ virtual void            LeaveCatch(GCInfoToken gcInfoToken,
                                    PCONTEXT pCtx)=0;
 #endif // FEATURE_EH_FUNCLETS
 
-#ifdef EnC_SUPPORTED
+#ifdef FEATURE_ENC_SUPPORTED
 
 /*
     Last chance for the runtime support to do fixups in the context
@@ -347,7 +347,7 @@ virtual HRESULT FixContextForEnC(PCONTEXT        pCtx,
                const ICorDebugInfo::NativeVarInfo * newMethodVars,
                                     SIZE_T          newMethodVarsCount) = 0;
 
-#endif // EnC_SUPPORTED
+#endif // FEATURE_ENC_SUPPORTED
 
 #endif // #ifndef DACCESS_COMPILE
 
@@ -597,7 +597,7 @@ virtual void LeaveCatch(GCInfoToken gcInfoToken,
                          PCONTEXT pCtx);
 #endif // FEATURE_EH_FUNCLETS
 
-#ifdef EnC_SUPPORTED
+#ifdef FEATURE_ENC_SUPPORTED
 /*
     Last chance for the runtime support to do fixups in the context
     before execution continues inside an EnC updated function.
@@ -610,7 +610,7 @@ HRESULT FixContextForEnC(PCONTEXT        pCtx,
                             EECodeInfo    * pNewCodeInfo,
        const ICorDebugInfo::NativeVarInfo * newMethodVars,
                             SIZE_T          newMethodVarsCount);
-#endif // EnC_SUPPORTED
+#endif // FEATURE_ENC_SUPPORTED
 
 #endif // #ifndef DACCESS_COMPILE
 

src/coreclr/jit/codegenxarch.cpp

@@ -8910,7 +8910,7 @@ void CodeGen::genCreateAndStoreGCInfoX64(unsigned codeSize, unsigned prologSize
         //  -saved bool for synchronized methods
 
         // slots for ret address + FP + EnC callee-saves
-        int preservedAreaSize = (2 + genCountBits(RBM_ENC_CALLEE_SAVED)) * REGSIZE_BYTES;
+        int preservedAreaSize = (2 + genCountBits((uint64_t)RBM_ENC_CALLEE_SAVED)) * REGSIZE_BYTES;
 
         if (compiler->info.compFlags & CORINFO_FLG_SYNCH)
         {

src/coreclr/jit/targetamd64.h

@@ -303,6 +303,9 @@
   /* NOTE: Sync with variable name defined in compiler.h */
   #define REG_CALLEE_SAVED_ORDER   REG_EBX,REG_ETW_FRAMED_EBP_LIST REG_R12,REG_R13,REG_R14,REG_R15
   #define RBM_CALLEE_SAVED_ORDER   RBM_EBX,RBM_ETW_FRAMED_EBP_LIST RBM_R12,RBM_R13,RBM_R14,RBM_R15
+
+  // For SysV we have more volatile registers so we do not save any callee saves for EnC.
+  #define RBM_ENC_CALLEE_SAVED     0
 #else // !UNIX_AMD64_ABI
   #define CNT_CALLEE_SAVED         (7 + REG_ETW_FRAMED_EBP_COUNT)
   #define CNT_CALLEE_TRASH         (7)
@@ -314,6 +317,9 @@
   /* NOTE: Sync with variable name defined in compiler.h */
   #define REG_CALLEE_SAVED_ORDER   REG_EBX,REG_ESI,REG_EDI,REG_ETW_FRAMED_EBP_LIST REG_R12,REG_R13,REG_R14,REG_R15
   #define RBM_CALLEE_SAVED_ORDER   RBM_EBX,RBM_ESI,RBM_EDI,RBM_ETW_FRAMED_EBP_LIST RBM_R12,RBM_R13,RBM_R14,RBM_R15
+
+  // Callee-preserved registers we always save and allow use of for EnC code, since there are quite few volatile registers.
+  #define RBM_ENC_CALLEE_SAVED     (RBM_RSI | RBM_RDI)
 #endif // !UNIX_AMD64_ABI
 
   #define CNT_CALLEE_TRASH_FLOAT   get_CNT_CALLEE_TRASH_FLOAT()
@@ -327,9 +333,6 @@
   #define CALLEE_SAVED_REG_MAXSZ   (CNT_CALLEE_SAVED*REGSIZE_BYTES)
   #define CALLEE_SAVED_FLOAT_MAXSZ (CNT_CALLEE_SAVED_FLOAT*16)
 
-  // callee-preserved registers we always save and allow use of for EnC code
-  #define RBM_ENC_CALLEE_SAVED     (RBM_RSI | RBM_RDI)
-
   // register to hold shift amount
   #define REG_SHIFT                REG_ECX
   #define RBM_SHIFT                RBM_ECX

src/coreclr/pal/inc/pal.h

@@ -4490,6 +4490,7 @@ struct PAL_SEHException
         ExceptionPointers.ExceptionRecord = ex.ExceptionPointers.ExceptionRecord;
         ExceptionPointers.ContextRecord = ex.ExceptionPointers.ContextRecord;
         TargetFrameSp = ex.TargetFrameSp;
+        TargetIp = ex.TargetIp;
         RecordsOnStack = ex.RecordsOnStack;
         IsExternal = ex.IsExternal;
         ManagedToNativeExceptionCallback = ex.ManagedToNativeExceptionCallback;
@@ -4512,6 +4513,8 @@ struct PAL_SEHException
     EXCEPTION_POINTERS ExceptionPointers;
     // Target frame stack pointer set before the 2nd pass.
     SIZE_T TargetFrameSp;
+    SIZE_T TargetIp;
+    SIZE_T ReturnValue;
     bool RecordsOnStack;
     // The exception is a hardware exception coming from a native code out of
     // the well known runtime helpers
@@ -4525,6 +4528,7 @@ struct PAL_SEHException
         ExceptionPointers.ExceptionRecord = pExceptionRecord;
         ExceptionPointers.ContextRecord = pContextRecord;
         TargetFrameSp = NoTargetFrameSp;
+        TargetIp = 0;
         RecordsOnStack = onStack;
         IsExternal = false;
         ManagedToNativeExceptionCallback = NULL;
@@ -4564,6 +4568,7 @@ struct PAL_SEHException
         ExceptionPointers.ExceptionRecord = NULL;
         ExceptionPointers.ContextRecord = NULL;
         TargetFrameSp = NoTargetFrameSp;
+        TargetIp = 0;
         RecordsOnStack = false;
         IsExternal = false;
         ManagedToNativeExceptionCallback = NULL;

src/coreclr/vm/eetwain.cpp

@@ -792,7 +792,7 @@ bool        VarIsInReg(ICorDebugInfo::VarLoc varLoc)
     }
 }
 
-#ifdef EnC_SUPPORTED
+#ifdef FEATURE_ENC_SUPPORTED
 /*****************************************************************************
  *  Last chance for the runtime support to do fixups in the context
  *  before execution continues inside an EnC updated function.
@@ -831,7 +831,6 @@ HRESULT EECodeManager::FixContextForEnC(PCONTEXT         pCtx,
     T_CONTEXT oldCtx = *pCtx;
 
 #if defined(TARGET_X86)
-    LOG((LF_CORDB, LL_INFO100, "EECM::FixContextForEnC\n"));
 
     /* Extract the necessary information from the info block header */
 
@@ -997,22 +996,29 @@ HRESULT EECodeManager::FixContextForEnC(PCONTEXT         pCtx,
     _ASSERTE(pOldCodeInfo->HasFrameRegister());
     _ASSERTE(pNewCodeInfo->HasFrameRegister());
 
-    LOG((LF_CORDB, LL_INFO100, "EECM::FixContextForEnC: Old and new fixed stack sizes are %u and %u\n", oldFixedStackSize, newFixedStackSize));
-
-    // x64: SP == FP before localloc
-    if (oldStackBase != GetFP(&oldCtx))
-        return E_FAIL;
 #elif defined(TARGET_ARM64)
     DWORD oldFixedStackSize = oldGcDecoder.GetSizeOfEditAndContinueFixedStackFrame();
     DWORD newFixedStackSize = newGcDecoder.GetSizeOfEditAndContinueFixedStackFrame();
+#else
+    PORTABILITY_ASSERT("Edit-and-continue not enabled on this platform.");
+#endif
 
     LOG((LF_CORDB, LL_INFO100, "EECM::FixContextForEnC: Old and new fixed stack sizes are %u and %u\n", oldFixedStackSize, newFixedStackSize));
 
-    // ARM64: FP + 16 == SP + oldFixedStackSize before localloc
-    if (GetFP(&oldCtx) + 16 != oldStackBase + oldFixedStackSize)
+#if defined(TARGET_AMD64) && defined(TARGET_WINDOWS)
+    // win-x64: SP == FP before localloc
+    if (oldStackBase != GetFP(&oldCtx))
+    {
         return E_FAIL;
+    }
 #else
-    PORTABILITY_ASSERT("Edit-and-continue not enabled on this platform.");
+    // All other 64-bit targets use frame chaining with the FP stored right below the
+    // return address (LR is always pushed on arm64). FP + 16 == SP + oldFixedStackSize
+    // gives the caller's SP before stack alloc.
+    if (GetFP(&oldCtx) + 16 != oldStackBase + oldFixedStackSize)
+    {
+        return E_FAIL;
+    }
 #endif
 
     // EnC remap inside handlers is not supported
@@ -1028,14 +1034,15 @@ HRESULT EECodeManager::FixContextForEnC(PCONTEXT         pCtx,
     TADDR callerSP = oldStackBase + oldFixedStackSize;
 
 #ifdef _DEBUG
-    // If the old method has a PSPSym, then its value should == FP for x64 and callerSP for arm64
+    // If the old method has a PSPSym, then its value should == initial-SP (i.e.
+    // oldStackBase) for x64 and callerSP for arm64
     INT32 nOldPspSymStackSlot = oldGcDecoder.GetPSPSymStackSlot();
     if (nOldPspSymStackSlot != NO_PSP_SYM)
     {
 #if defined(TARGET_AMD64)
         TADDR oldPSP = *PTR_TADDR(oldStackBase + nOldPspSymStackSlot);
-        _ASSERTE(oldPSP == GetFP(&oldCtx));
-#elif defined(TARGET_ARM64)
+        _ASSERTE(oldPSP == oldStackBase);
+#else
         TADDR oldPSP = *PTR_TADDR(callerSP + nOldPspSymStackSlot);
         _ASSERTE(oldPSP == callerSP);
 #endif
@@ -1222,8 +1229,7 @@ HRESULT EECodeManager::FixContextForEnC(PCONTEXT         pCtx,
 
 #if defined(TARGET_X86)
         // Zero out all  the registers as some may hold new variables.
-        pCtx->Eax = pCtx->Ecx = pCtx->Edx = pCtx->Ebx =
-        pCtx->Esi = pCtx->Edi = 0;
+        pCtx->Eax = pCtx->Ecx = pCtx->Edx = pCtx->Ebx = pCtx->Esi = pCtx->Edi = 0;
 
         // 3) zero out the stack frame - this'll initialize _all_ variables
 
@@ -1240,7 +1246,7 @@ HRESULT EECodeManager::FixContextForEnC(PCONTEXT         pCtx,
         _ASSERTE( frameHeaderSize <= oldInfo.stackSize );
         _ASSERTE( GetSizeOfFrameHeaderForEnC( &oldInfo ) == frameHeaderSize );
 
-#elif defined(TARGET_AMD64)
+#elif defined(TARGET_AMD64) && !defined(UNIX_AMD64_ABI)
 
         // Next few statements zero out all registers that may end up holding new variables.
 
@@ -1276,14 +1282,24 @@ HRESULT EECodeManager::FixContextForEnC(PCONTEXT         pCtx,
         // For EnC-compliant x64 code, FP == SP.  Since SP changed above, update FP now
         pCtx->Rbp = newStackBase;
 
-#elif defined(TARGET_ARM64)
+#else
+#if defined(TARGET_ARM64)
         // Zero out volatile part of stack frame
         // x0-x17
         memset(&pCtx->X[0], 0, sizeof(pCtx->X[0]) * 18);
         // v0-v7
         memset(&pCtx->V[0], 0, sizeof(pCtx->V[0]) * 8);
         // v16-v31
         memset(&pCtx->V[16], 0, sizeof(pCtx->V[0]) * 16);
+#elif defined(TARGET_AMD64)
+        // SysV ABI
+        pCtx->Rax = pCtx->Rdi = pCtx->Rsi = pCtx->Rdx = pCtx->Rcx = pCtx->R8 = pCtx->R9 = 0;
+
+        // volatile float registers
+        memset(&pCtx->Xmm0, 0, sizeof(pCtx->Xmm0) * 16);
+#else
+        PORTABILITY_ASSERT("Edit-and-continue not enabled on this platform.");
+#endif
 
         TADDR newStackBase = callerSP - newFixedStackSize;
 
@@ -1293,12 +1309,9 @@ HRESULT EECodeManager::FixContextForEnC(PCONTEXT         pCtx,
         _ASSERTE(frameHeaderSize <= oldFixedStackSize);
         _ASSERTE(frameHeaderSize <= newFixedStackSize);
 
-        // EnC prolog saves only fp,lr and does it at sp-16. It should already
-        // be set up from previous version.
+        // EnC prolog saves only FP (and LR on arm64), and FP points to saved FP for frame chaining.
+        // These should already be set up from previous version.
         _ASSERTE(GetFP(pCtx) == callerSP - 16);
-
-#else   // !X86
-        PORTABILITY_ASSERT("Edit-and-continue not enabled on this platform.");
 #endif
 
         // Perform some debug-only sanity checks on stack variables.  Some checks are
@@ -1416,7 +1429,7 @@ HRESULT EECodeManager::FixContextForEnC(PCONTEXT         pCtx,
         if (nNewPspSymStackSlot != NO_PSP_SYM)
         {
 #if defined(TARGET_AMD64)
-            *PTR_TADDR(newStackBase + nNewPspSymStackSlot) = GetFP(pCtx);
+            *PTR_TADDR(newStackBase + nNewPspSymStackSlot) = newStackBase;
 #elif defined(TARGET_ARM64)
             *PTR_TADDR(callerSP + nNewPspSymStackSlot) = callerSP;
 #else

src/coreclr/vm/encee.cpp

@@ -733,9 +733,11 @@ HRESULT EditAndContinueModule::ResumeInUpdatedFunction(
     // Win32 handlers on the stack so cannot ever return from this function.
     EEPOLICY_HANDLE_FATAL_ERROR(CORDBG_E_ENC_INTERNAL_ERROR);
     return E_FAIL;
-#endif // #if defined(TARGET_ARM) || defined(TARGET_LOONGARCH64)
+#endif // #if defined(TARGET_ARM) || defined(TARGET_LOONGARCH64) || defined(TARGET_RISCV64)
+
 }
 
+#ifdef FEATURE_ENC_SUPPORTED
 //---------------------------------------------------------------------------------------
 //
 // FixContextAndResume - Modify the thread context for EnC remap and resume execution
@@ -871,6 +873,8 @@ NOINLINE void EditAndContinueModule::FixContextAndResume(
     LOG((LF_ENC, LL_ERROR, "**Error** EnCModule::ResumeInUpdatedFunction returned from ResumeAtJit"));
     _ASSERTE(!"Should not return from ResumeAtJit()");
 }
+#endif // #ifdef FEATURE_ENC_SUPPORTED
+
 #endif // #ifndef DACCESS_COMPILE
 
 //---------------------------------------------------------------------------------------

src/coreclr/vm/encee.h

@@ -247,12 +247,14 @@ class EditAndContinueModule : public Module
                                     SIZE_T newILOffset,
                                     T_CONTEXT *pContext);
 
+#ifdef FEATURE_ENC_SUPPORTED
     // Modify the thread context for EnC remap and resume execution
     void FixContextAndResume(MethodDesc *pMD,
                              void *oldDebuggerFuncHandle,
                              T_CONTEXT *pContext,
                              EECodeInfo *pOldCodeInfo,
                              EECodeInfo *pNewCodeInfo);
+#endif // FEATURE_ENC_SUPPORTED
 
     // Get a pointer to the value of a field added by EnC or return NULL if it doesn't exist
     PTR_CBYTE ResolveField(OBJECTREF thisPointer,

src/coreclr/vm/excep.h

@@ -710,10 +710,9 @@ bool IsInterceptableException(Thread *pThread);
 // perform simple checking to see if the current exception is intercepted
 bool CheckThreadExceptionStateForInterception();
 
-#ifndef TARGET_UNIX
-// Currently, only Windows supports ClrUnwindEx (used inside ClrDebuggerDoUnwindAndIntercept)
+#if defined(TARGET_AMD64) || defined(TARGET_ARM64) || defined(TARGET_ARM) || defined(TARGET_X86)
 #define DEBUGGER_EXCEPTION_INTERCEPTION_SUPPORTED
-#endif // !TARGET_UNIX
+#endif // defined(TARGET_AMD64) || defined(TARGET_ARM64) || defined(TARGET_ARM) || defined(TARGET_X86)
 
 #ifdef DEBUGGER_EXCEPTION_INTERCEPTION_SUPPORTED
 // Intercept the current exception and start an unwind.  This function may never return.

src/coreclr/vm/exceptionhandling.cpp

@@ -46,6 +46,10 @@ ClrUnwindEx(EXCEPTION_RECORD* pExceptionRecord,
                  UINT_PTR          TargetFrameSp);
 #endif // !TARGET_UNIX
 
+#if defined(TARGET_UNIX) && !defined(DACCESS_COMPILE)
+VOID UnwindManagedExceptionPass2(PAL_SEHException& ex, CONTEXT* unwindStartContext);
+#endif // TARGET_UNIX && !DACCESS_COMPILE
+
 #ifdef USE_CURRENT_CONTEXT_IN_FILTER
 inline void CaptureNonvolatileRegisters(PKNONVOLATILE_CONTEXT pNonvolatileContext, PCONTEXT pContext)
 {
@@ -4210,7 +4214,16 @@ EXCEPTION_DISPOSITION ClrDebuggerDoUnwindAndIntercept(X86_FIRST_ARG(EXCEPTION_RE
                                                            (PBYTE*)&uInterceptStackFrame,
                                                            NULL, NULL);
 
+#ifdef TARGET_UNIX
+    CONTEXT *pContext = pThread->GetExceptionState()->GetContextRecord();
+    PAL_SEHException ex(pThread->GetExceptionState()->GetExceptionRecord(), pContext, /* onStack */ false);
+    ex.TargetIp = INVALID_RESUME_ADDRESS;
+    ex.TargetFrameSp = uInterceptStackFrame;
+    ex.ReturnValue = (UINT_PTR)pThread;
+    UnwindManagedExceptionPass2(ex, pContext);
+#else // TARGET_UNIX
     ClrUnwindEx(pExceptionRecord, (UINT_PTR)pThread, INVALID_RESUME_ADDRESS, uInterceptStackFrame);
+#endif // TARGET_UNIX
 
     UNREACHABLE();
 }
@@ -4554,6 +4567,29 @@ VOID UnwindManagedExceptionPass2(PAL_SEHException& ex, CONTEXT* unwindStartConte
 
     } while (Thread::IsAddressInCurrentStack(sp) && (establisherFrame != ex.TargetFrameSp));
 
+#ifdef DEBUGGER_EXCEPTION_INTERCEPTION_SUPPORTED
+    if ((establisherFrame == ex.TargetFrameSp) && (ex.TargetIp != 0))
+    {
+#ifdef TARGET_AMD64
+#define RETURN_REG Rax
+#elif defined(TARGET_ARM64)
+#define RETURN_REG X0
+#elif defined(TARGET_ARM)
+#define RETURN_REG R0
+#elif defined(TARGET_X86)
+#define RETURN_REG Eax
+#else
+#error Missing definition of RETURN_REG for the current architecture
+#endif
+        currentFrameContext->RETURN_REG = ex.ReturnValue;
+        if (ex.GetExceptionRecord()->ExceptionCode != STATUS_UNWIND_CONSOLIDATE)
+        {
+            SetIP(currentFrameContext, ex.TargetIp);
+        }
+        ExceptionTracker::ResumeExecution(currentFrameContext);
+    }
+#endif // DEBUGGER_EXCEPTION_INTERCEPTION_SUPPORTED
+
     _ASSERTE(!"UnwindManagedExceptionPass2: Unwinding failed. Reached the end of the stack");
     EEPOLICY_HANDLE_FATAL_ERROR(COR_E_EXECUTIONENGINE);
 }