- implement throwing by storing exception information in a struct, then return from the jitted function and throw from c++

src/scripting/vm/jit.cpp

@@ -292,22 +292,6 @@ static int64_t ToMemAddress(const void *d)
 	return (int64_t)(ptrdiff_t)d;
 }
 
-void setPCOnAbort(VMScriptFunction *sfunc, VMOP* pc) {
-	sfunc->pcOnJitAbort = pc;
-}
-
-void emitAbortExceptionCall(asmjit::X86Compiler& cc, VMScriptFunction* sfunc, const VMOP* pc, EVMAbortException reason, const char* moreinfo) {
-	using namespace asmjit;
-
-	CCFuncCall* setPCCall = cc.call(imm_ptr((void*)setPCOnAbort), FuncSignature2<void, VMScriptFunction*, VMOP*>(CallConv::kIdHost));
-	setPCCall->setArg(0, imm_ptr(sfunc));
-	setPCCall->setArg(1, imm_ptr(pc));
-
-	CCFuncCall* throwAbortCall = cc.call(imm_ptr((void*)ThrowAbortException), FuncSignatureT<void, int, const char*>(CallConv::kIdHost));
-	throwAbortCall->setArg(0, imm(reason));
-	throwAbortCall->setArg(1, imm_ptr(moreinfo));
-}
-
 static void CallSqrt(asmjit::X86Compiler& cc, const asmjit::X86Xmm &a, const asmjit::X86Xmm &b)
 {
 	using namespace asmjit;
@@ -317,6 +301,43 @@ static void CallSqrt(asmjit::X86Compiler& cc, const asmjit::X86Xmm &a, const asm
 	call->setArg(0, b);
 }
 
+static void EmitThrowException(asmjit::X86Compiler& cc, asmjit::X86Gp exceptInfo, const VMOP* pc, EVMAbortException reason)
+{
+	using namespace asmjit;
+
+	// Update JitExceptionInfo struct
+	cc.mov(x86::dword_ptr(exceptInfo, 0 * 4), (int32_t)reason);
+	#ifdef ASMJIT_ARCH_X64
+	cc.mov(x86::qword_ptr(exceptInfo, 4 * 4), ToMemAddress(pc));
+	#else
+	cc.mov(x86::dword_ptr(exceptInfo, 4 * 4), ToMemAddress(pc));
+	#endif
+
+	// Return from function
+	X86Gp vReg = cc.newInt32();
+	cc.mov(vReg, 0);
+	cc.ret(vReg);
+}
+
+static void EmitThrowException(asmjit::X86Compiler& cc, asmjit::X86Gp exceptInfo, const VMOP* pc, EVMAbortException reason, asmjit::X86Gp arg1)
+{
+	using namespace asmjit;
+
+	// Update JitExceptionInfo struct
+	cc.mov(x86::dword_ptr(exceptInfo, 0 * 4), (int32_t)reason);
+	cc.mov(x86::dword_ptr(exceptInfo, 1 * 4), arg1);
+	#ifdef ASMJIT_ARCH_X64
+	cc.mov(x86::qword_ptr(exceptInfo, 4 * 4), ToMemAddress(pc));
+	#else
+	cc.mov(x86::dword_ptr(exceptInfo, 4 * 4), ToMemAddress(pc));
+	#endif
+
+	// Return from function
+	X86Gp vReg = cc.newInt32();
+	cc.mov(vReg, 0);
+	cc.ret(vReg);
+}
+
 JitFuncPtr JitCompile(VMScriptFunction *sfunc)
 {
 #if 0 // For debugging
@@ -345,12 +366,14 @@ JitFuncPtr JitCompile(VMScriptFunction *sfunc)
 		X86Gp vmregs = cc.newIntPtr("vmregs"); // void *vmregs
 		X86Gp ret = cc.newIntPtr("ret"); // VMReturn *ret
 		X86Gp numret = cc.newInt32("numret"); // int numret
+		X86Gp exceptInfo = cc.newIntPtr("exceptinfo"); // JitExceptionInfo *exceptInfo
 
-		cc.addFunc(FuncSignature4<int, void *, void *, void *, int>());
+		cc.addFunc(FuncSignature5<int, void *, void *, void *, int, void *>());
 		cc.setArg(0, stack);
 		cc.setArg(1, vmregs);
 		cc.setArg(2, ret);
 		cc.setArg(3, numret);
+		cc.setArg(4, exceptInfo);
 
 		const int *konstd = sfunc->KonstD;
 		const double *konstf = sfunc->KonstF;
@@ -929,7 +952,7 @@ JitFuncPtr JitCompile(VMScriptFunction *sfunc)
 				cc.mov(regD[A], tmp0);
 
 				cc.bind(label);
-				emitAbortExceptionCall(cc, sfunc, pc, X_DIVISION_BY_ZERO, nullptr);
+				EmitThrowException(cc, exceptInfo, pc, X_DIVISION_BY_ZERO);
 				break;
 			}
 			case OP_DIV_RK:

src/scripting/vm/vm.h

@@ -45,6 +45,8 @@
 #include "scripting/backend/scopebarrier.h"
 
 class DObject;
+union VMOP;
+class VMScriptFunction;
 
 extern FMemArena ClassDataAllocator;
 
@@ -104,6 +106,7 @@ public:
 
 // This must be a separate function because the VC compiler would otherwise allocate memory on the stack for every separate instance of the exception object that may get thrown.
 void ThrowAbortException(EVMAbortException reason, const char *moreinfo, ...);
+void ThrowAbortException(VMScriptFunction *sfunc, VMOP *line, EVMAbortException reason, const char *moreinfo, ...);
 
 struct VMReturn
 {

src/scripting/vm/vmexec.h

@@ -80,17 +80,16 @@ static int Exec(VMFrameStack *stack, const VMOP *pc, VMReturn *ret, int numret)
 			sfunc->JitFunc = JitCompile(sfunc);
 			sfunc->JitCompiled = true;
 		}
-		if (sfunc->JitFunc) {
+		if (sfunc->JitFunc)
-			try {
+		{
-				return sfunc->JitFunc(stack, &reg, ret, numret);
+			JitExceptionInfo exceptInfo;
-			}
+			exceptInfo.reason = -1;
-			catch (CVMAbortException &err)
+			int result = sfunc->JitFunc(stack, &reg, ret, numret, &exceptInfo);
+			if (exceptInfo.reason != -1)
 			{
-				err.MaybePrintMessage();
+				ThrowAbortException(sfunc, exceptInfo.pcOnJitAbort, (EVMAbortException)exceptInfo.reason, nullptr);
-				err.stacktrace.AppendFormat("Called from %s at %s, line %d\n", sfunc->PrintableName.GetChars(), sfunc->SourceFileName.GetChars(), sfunc->PCToLine(sfunc->pcOnJitAbort));
-				// PrintParameters(reg.param + f->NumParam - B, B);
-				throw;
 			}
+			return result;
 		}
 	}
 

src/scripting/vm/vmframe.cpp

@@ -577,6 +577,16 @@ void ThrowAbortException(EVMAbortException reason, const char *moreinfo, ...)
 	va_end(ap);
 }
 
+void ThrowAbortException(VMScriptFunction *sfunc, VMOP *line, EVMAbortException reason, const char *moreinfo, ...)
+{
+	va_list ap;
+	va_start(ap, moreinfo);
+	CVMAbortException err(reason, moreinfo, ap);
+	err.stacktrace.AppendFormat("Called from %s at %s, line %d\n", sfunc->PrintableName.GetChars(), sfunc->SourceFileName.GetChars(), sfunc->PCToLine(line));
+	throw err;
+	va_end(ap);
+}
+
 DEFINE_ACTION_FUNCTION(DObject, ThrowAbortException)
 {
 	PARAM_PROLOGUE;

src/scripting/vm/vmintern.h

@@ -437,7 +437,14 @@ extern thread_local VMFrameStack GlobalVMStack;
 
 typedef std::pair<const class PType *, unsigned> FTypeAndOffset;
 
-typedef int(*JitFuncPtr)(VMFrameStack *stack, const void *vmregs, VMReturn *ret, int numret);
+struct JitExceptionInfo
+{
+	int32_t reason; // EVMAbortException
+	int32_t args[3];
+	VMOP* pcOnJitAbort;
+};
+
+typedef int(*JitFuncPtr)(VMFrameStack *stack, const void *vmregs, VMReturn *ret, int numret, JitExceptionInfo *exceptInfo);
 
 class VMScriptFunction : public VMFunction
 {
@@ -471,7 +478,6 @@ public:
 
 	bool JitCompiled = false;
 	JitFuncPtr JitFunc = nullptr;
-	VMOP* pcOnJitAbort = nullptr;
 
 	void InitExtra(void *addr);
 	void DestroyExtra(void *addr);