- modify exception checks to jump ahead if the exception is to be thrown as it limits static misprediction

src/scripting/vm/jit.cpp

@@ -678,11 +678,9 @@ void JitCompiler::EmitPopFrame()
 
 void JitCompiler::EmitNullPointerThrow(int index, EVMAbortException reason)
 {
-	auto label = cc.newLabel();
+	auto label = EmitThrowExceptionLabel(reason);
 	cc.test(regA[index], regA[index]);
-	cc.jne(label);
+	cc.je(label);
-	EmitThrowException(reason);
-	cc.bind(label);
 }
 
 void JitCompiler::ThrowException(VMScriptFunction *func, VMOP *line, int reason)
@@ -705,6 +703,16 @@ void JitCompiler::EmitThrowException(EVMAbortException reason)
 	call->setArg(2, asmjit::imm(reason));
 }
 
+asmjit::Label JitCompiler::EmitThrowExceptionLabel(EVMAbortException reason)
+{
+	auto label = cc.newLabel();
+	auto cursor = cc.getCursor();
+	cc.bind(label);
+	EmitThrowException(reason);
+	cc.setCursor(cursor);
+	return label;
+}
+
 asmjit::X86Gp JitCompiler::CheckRegD(int r0, int r1)
 {
 	if (r0 != r1)

src/scripting/vm/jit_flow.cpp

@@ -50,11 +50,9 @@ void JitCompiler::EmitIJMP()
 
 void JitCompiler::EmitVTBL()
 {
-	auto notnull = cc.newLabel();
+	auto label = EmitThrowExceptionLabel(X_READ_NIL);
 	cc.test(regA[B], regA[B]);
-	cc.jnz(notnull);
+	cc.jz(label);
-	EmitThrowException(X_READ_NIL);
-	cc.bind(notnull);
 
 	auto result = newResultIntPtr();
 	auto call = CreateCall<VMFunction*, DObject*, int>([](DObject *o, int c) -> VMFunction* {
@@ -70,11 +68,9 @@ void JitCompiler::EmitVTBL()
 
 void JitCompiler::EmitSCOPE()
 {
-	auto notnull = cc.newLabel();
+	auto label = EmitThrowExceptionLabel(X_READ_NIL);
 	cc.test(regA[A], regA[A]);
-	cc.jnz(notnull);
+	cc.jz(label);
-	EmitThrowException(X_READ_NIL);
-	cc.bind(notnull);
 
 	auto f = newTempIntPtr();
 	cc.mov(f, asmjit::imm_ptr(konsta[C].v));
@@ -355,48 +351,50 @@ void JitCompiler::EmitTHROW()
 
 void JitCompiler::EmitBOUND()
 {
+	auto cursor = cc.getCursor();
 	auto label = cc.newLabel();
-
+	cc.bind(label);
-	cc.cmp(regD[A], (int)BC);
-	cc.jb(label);
-
 	auto call = CreateCall<void, VMScriptFunction *, VMOP *, int, int>(&JitCompiler::ThrowArrayOutOfBounds);
 	call->setArg(0, asmjit::imm_ptr(sfunc));
 	call->setArg(1, asmjit::imm_ptr(pc));
 	call->setArg(2, regD[A]);
 	call->setArg(3, asmjit::imm(BC));
+	cc.setCursor(cursor);
 
-	cc.bind(label);
+	cc.cmp(regD[A], (int)BC);
+	cc.jae(label);
 }
 
 void JitCompiler::EmitBOUND_K()
 {
+	auto cursor = cc.getCursor();
 	auto label = cc.newLabel();
-	cc.cmp(regD[A], (int)konstd[BC]);
+	cc.bind(label);
-	cc.jb(label);
-
 	auto call = CreateCall<void, VMScriptFunction *, VMOP *, int, int>(&JitCompiler::ThrowArrayOutOfBounds);
 	call->setArg(0, asmjit::imm_ptr(sfunc));
 	call->setArg(1, asmjit::imm_ptr(pc));
 	call->setArg(2, regD[A]);
 	call->setArg(3, asmjit::imm(konstd[BC]));
+	cc.setCursor(cursor);
 
-	cc.bind(label);
+	cc.cmp(regD[A], (int)konstd[BC]);
+	cc.jae(label);
 }
 
 void JitCompiler::EmitBOUND_R()
 {
+	auto cursor = cc.getCursor();
 	auto label = cc.newLabel();
-	cc.cmp(regD[A], regD[B]);
+	cc.bind(label);
-	cc.jb(label);
-
 	auto call = CreateCall<void, VMScriptFunction *, VMOP *, int, int>(&JitCompiler::ThrowArrayOutOfBounds);
 	call->setArg(0, asmjit::imm_ptr(sfunc));
 	call->setArg(1, asmjit::imm_ptr(pc));
 	call->setArg(2, regD[A]);
 	call->setArg(3, regD[B]);
+	cc.setCursor(cursor);
 
-	cc.bind(label);
+	cc.cmp(regD[A], regD[B]);
+	cc.jae(label);
 }
 
 void JitCompiler::ThrowArrayOutOfBounds(VMScriptFunction *func, VMOP *line, int index, int size)

src/scripting/vm/jit_load.cpp

@@ -78,11 +78,9 @@ void JitCompiler::EmitLFP()
 
 void JitCompiler::EmitMETA()
 {
-	auto label = cc.newLabel();
+	auto label = EmitThrowExceptionLabel(X_READ_NIL);
 	cc.test(regA[B], regA[B]);
-	cc.jne(label);
+	cc.je(label);
-	EmitThrowException(X_READ_NIL);
-	cc.bind(label);
 
 	auto result = newResultIntPtr();
 	auto call = CreateCall<uint8_t*, DObject*>([](DObject *o) { return o->GetClass()->Meta; });
@@ -93,11 +91,9 @@ void JitCompiler::EmitMETA()
 
 void JitCompiler::EmitCLSS()
 {
-	auto label = cc.newLabel();
+	auto label = EmitThrowExceptionLabel(X_READ_NIL);
 	cc.test(regA[B], regA[B]);
-	cc.jne(label);
+	cc.je(label);
-	EmitThrowException(X_READ_NIL);
-	cc.bind(label);
 
 	auto result = newResultIntPtr();
 	auto call = CreateCall<PClass*, DObject*>([](DObject *o) { return o->GetClass(); });

src/scripting/vm/jit_math.cpp

@@ -200,14 +200,11 @@ void JitCompiler::EmitDIV_RR()
 {
 	auto tmp0 = newTempInt32();
 	auto tmp1 = newTempInt32();
-	auto label = cc.newLabel();
 
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.test(regD[C], regD[C]);
-	cc.jne(label);
+	cc.je(label);
 
-	EmitThrowException(X_DIVISION_BY_ZERO);
-
-	cc.bind(label);
 	cc.mov(tmp0, regD[B]);
 	cc.cdq(tmp1, tmp0);
 	cc.idiv(tmp1, tmp0, regD[C]);
@@ -227,21 +224,21 @@ void JitCompiler::EmitDIV_RK()
 		cc.idiv(tmp1, tmp0, asmjit::x86::ptr(konstTmp));
 		cc.mov(regD[A], tmp0);
 	}
-	else EmitThrowException(X_DIVISION_BY_ZERO);
+	else
+	{
+		EmitThrowException(X_DIVISION_BY_ZERO);
+	}
 }
 
 void JitCompiler::EmitDIV_KR()
 {
 	auto tmp0 = newTempInt32();
 	auto tmp1 = newTempInt32();
-	auto label = cc.newLabel();
 
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.test(regD[C], regD[C]);
-	cc.jne(label);
+	cc.je(label);
 
-	EmitThrowException(X_DIVISION_BY_ZERO);
-
-	cc.bind(label);
 	cc.mov(tmp0, konstd[B]);
 	cc.cdq(tmp1, tmp0);
 	cc.idiv(tmp1, tmp0, regD[C]);
@@ -252,14 +249,11 @@ void JitCompiler::EmitDIVU_RR()
 {
 	auto tmp0 = newTempInt32();
 	auto tmp1 = newTempInt32();
-	auto label = cc.newLabel();
 
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.test(regD[C], regD[C]);
-	cc.jne(label);
+	cc.je(label);
 
-	EmitThrowException(X_DIVISION_BY_ZERO);
-
-	cc.bind(label);
 	cc.mov(tmp0, regD[B]);
 	cc.mov(tmp1, 0);
 	cc.div(tmp1, tmp0, regD[C]);
@@ -279,21 +273,21 @@ void JitCompiler::EmitDIVU_RK()
 		cc.div(tmp1, tmp0, asmjit::x86::ptr(konstTmp));
 		cc.mov(regD[A], tmp0);
 	}
-	else EmitThrowException(X_DIVISION_BY_ZERO);
+	else
+	{
+		EmitThrowException(X_DIVISION_BY_ZERO);
+	}
 }
 
 void JitCompiler::EmitDIVU_KR()
 {
 	auto tmp0 = newTempInt32();
 	auto tmp1 = newTempInt32();
-	auto label = cc.newLabel();
 
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.test(regD[C], regD[C]);
-	cc.jne(label);
+	cc.je(label);
 
-	EmitThrowException(X_DIVISION_BY_ZERO);
-
-	cc.bind(label);
 	cc.mov(tmp0, konstd[B]);
 	cc.mov(tmp1, 0);
 	cc.div(tmp1, tmp0, regD[C]);
@@ -304,14 +298,11 @@ void JitCompiler::EmitMOD_RR()
 {
 	auto tmp0 = newTempInt32();
 	auto tmp1 = newTempInt32();
-	auto label = cc.newLabel();
 
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.test(regD[C], regD[C]);
-	cc.jne(label);
+	cc.je(label);
 
-	EmitThrowException(X_DIVISION_BY_ZERO);
-
-	cc.bind(label);
 	cc.mov(tmp0, regD[B]);
 	cc.cdq(tmp1, tmp0);
 	cc.idiv(tmp1, tmp0, regD[C]);
@@ -331,21 +322,21 @@ void JitCompiler::EmitMOD_RK()
 		cc.idiv(tmp1, tmp0, asmjit::x86::ptr(konstTmp));
 		cc.mov(regD[A], tmp1);
 	}
-	else EmitThrowException(X_DIVISION_BY_ZERO);
+	else
+	{
+		EmitThrowException(X_DIVISION_BY_ZERO);
+	}
 }
 
 void JitCompiler::EmitMOD_KR()
 {
 	auto tmp0 = newTempInt32();
 	auto tmp1 = newTempInt32();
-	auto label = cc.newLabel();
 
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.test(regD[C], regD[C]);
-	cc.jne(label);
+	cc.je(label);
 
-	EmitThrowException(X_DIVISION_BY_ZERO);
-
-	cc.bind(label);
 	cc.mov(tmp0, konstd[B]);
 	cc.cdq(tmp1, tmp0);
 	cc.idiv(tmp1, tmp0, regD[C]);
@@ -356,14 +347,11 @@ void JitCompiler::EmitMODU_RR()
 {
 	auto tmp0 = newTempInt32();
 	auto tmp1 = newTempInt32();
-	auto label = cc.newLabel();
 
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.test(regD[C], regD[C]);
-	cc.jne(label);
+	cc.je(label);
 
-	EmitThrowException(X_DIVISION_BY_ZERO);
-
-	cc.bind(label);
 	cc.mov(tmp0, regD[B]);
 	cc.mov(tmp1, 0);
 	cc.div(tmp1, tmp0, regD[C]);
@@ -383,21 +371,21 @@ void JitCompiler::EmitMODU_RK()
 		cc.div(tmp1, tmp0, asmjit::x86::ptr(konstTmp));
 		cc.mov(regD[A], tmp1);
 	}
-	else EmitThrowException(X_DIVISION_BY_ZERO);
+	else
+	{
+		EmitThrowException(X_DIVISION_BY_ZERO);
+	}
 }
 
 void JitCompiler::EmitMODU_KR()
 {
 	auto tmp0 = newTempInt32();
 	auto tmp1 = newTempInt32();
-	auto label = cc.newLabel();
 
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.test(regD[C], regD[C]);
-	cc.jne(label);
+	cc.je(label);
 
-	EmitThrowException(X_DIVISION_BY_ZERO);
-
-	cc.bind(label);
 	cc.mov(tmp0, konstd[B]);
 	cc.mov(tmp1, 0);
 	cc.div(tmp1, tmp0, regD[C]);
@@ -717,11 +705,10 @@ void JitCompiler::EmitMULF_RK()
 
 void JitCompiler::EmitDIVF_RR()
 {
-	auto label = cc.newLabel();
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.ptest(regF[C], regF[C]);
-	cc.jne(label);
+	cc.je(label);
-	EmitThrowException(X_DIVISION_BY_ZERO);
+
-	cc.bind(label);
 	auto rc = CheckRegF(C, A);
 	cc.movsd(regF[A], regF[B]);
 	cc.divsd(regF[A], rc);
@@ -753,11 +740,9 @@ void JitCompiler::EmitDIVF_KR()
 
 void JitCompiler::EmitMODF_RR()
 {
-	auto label = cc.newLabel();
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.ptest(regF[C], regF[C]);
-	cc.jne(label);
+	cc.je(label);
-	EmitThrowException(X_DIVISION_BY_ZERO);
-	cc.bind(label);
 
 	auto result = newResultXmmSd();
 	auto call = CreateCall<double, double, double>([](double a, double b) -> double
@@ -772,11 +757,9 @@ void JitCompiler::EmitMODF_RR()
 
 void JitCompiler::EmitMODF_RK()
 {
-	auto label = cc.newLabel();
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.ptest(regF[C], regF[C]);
-	cc.jne(label);
+	cc.je(label);
-	EmitThrowException(X_DIVISION_BY_ZERO);
-	cc.bind(label);
 
 	auto tmp = newTempXmmSd();
 	cc.movsd(tmp, asmjit::x86::ptr(ToMemAddress(&konstf[C])));
@@ -795,11 +778,9 @@ void JitCompiler::EmitMODF_KR()
 {
 	using namespace asmjit;
 
-	auto label = cc.newLabel();
+	auto label = EmitThrowExceptionLabel(X_DIVISION_BY_ZERO);
 	cc.ptest(regF[C], regF[C]);
-	cc.jne(label);
+	cc.je(label);
-	EmitThrowException(X_DIVISION_BY_ZERO);
-	cc.bind(label);
 
 	auto tmp = newTempXmmSd();
 	cc.movsd(tmp, x86::ptr(ToMemAddress(&konstf[B])));

src/scripting/vm/jitintern.h

@@ -146,6 +146,7 @@ private:
 
 	void EmitNullPointerThrow(int index, EVMAbortException reason);
 	void EmitThrowException(EVMAbortException reason);
+	asmjit::Label EmitThrowExceptionLabel(EVMAbortException reason);
 
 	static void ThrowArrayOutOfBounds(VMScriptFunction *func, VMOP *line, int index, int size);
 	static void ThrowException(VMScriptFunction *func, VMOP *line, int reason);