Minor optimization in JIT loader.

libclamav/c++/bytecode2llvm.cpp

@@ -810,6 +810,33 @@ public:
 	}
     }
 
+    Value *GEPOperand(Value *V) {
+	if (LoadInst *LI = dyn_cast<LoadInst>(V)) {
+	    Value *VI = LI->getOperand(0);
+	    StoreInst *SI = 0;
+	    for (Value::use_iterator I=VI->use_begin(),
+		 E=VI->use_end(); I != E; ++I) {
+		if (StoreInst *S = dyn_cast<StoreInst>(I)) {
+		    if (SI)
+			return V;
+		    SI = S;
+		} else if (!isa<LoadInst>(I))
+		    return V;
+	    }
+	    V = SI->getOperand(0);
+	}
+	if (EE->getTargetData()->getPointerSize() == 8) {
+	    // eliminate useless trunc, GEP can take i64 too
+	    if (TruncInst *I = dyn_cast<TruncInst>(V)) {
+		Value *Src = I->getOperand(0);
+		if (Src->getType() == Type::getInt64Ty(Context) &&
+		    I->getType() == Type::getInt32Ty(Context))
+		    return Src;
+	    }
+	}
+	return V;
+    }
+
     bool generate() {
 	TypeMap = new LLVMTypeMapper(Context, bc->types + 4, bc->num_types - 5);
 	for (unsigned i=0;i<bc->dbgnode_cnt;i++) {
@@ -871,6 +898,7 @@ public:
 	    Functions[j]->setCallingConv(CallingConv::Fast);
 	}
 	const Type *I32Ty = Type::getInt32Ty(Context);
+	PM.add(createDeadCodeEliminationPass());
 	if (!bc->trusted)
 	    PM.add(createClamBCRTChecks());
 	PM.add(new RuntimeLimits());
@@ -1162,6 +1190,7 @@ public:
 			    }
 			    CallInst *CI = Builder.CreateCall(DestF, args.begin(), args.end());
 			    CI->setCallingConv(CallingConv::Fast);
+			    CI->setDoesNotThrow(true);
 			    if (CI->getType()->getTypeID() != Type::VoidTyID)
 				Store(inst->dest, CI);
 			    break;
@@ -1176,7 +1205,9 @@ public:
 				operand_t op = inst->u.ops.ops[a];
 				args.push_back(convertOperand(func, DestF->getFunctionType()->getParamType(a+1), op));
 			    }
-			    Store(inst->dest, Builder.CreateCall(DestF, args.begin(), args.end()));
+			    CallInst *CI = Builder.CreateCall(DestF, args.begin(), args.end());
+			    CI->setDoesNotThrow(true);
+			    Store(inst->dest, CI);
 			    break;
 			}
 			case OP_BC_GEP1:
@@ -1184,7 +1215,7 @@ public:
 			    const Type *SrcTy = mapType(inst->u.three[0]);
 			    Value *V = convertOperand(func, SrcTy, inst->u.three[1]);
 			    Value *Op = convertOperand(func, I32Ty, inst->u.three[2]);
-//			    Op = Builder.CreateTrunc(Op, I32Ty);
+			    Op = GEPOperand(Op);
 			    if (!createGEP(inst->dest, V, &Op, &Op+1))
 				return false;
 			    break;
@@ -1196,7 +1227,7 @@ public:
 			    const Type *SrcTy = mapType(inst->u.three[0]);
 			    Value *V = convertOperand(func, SrcTy, inst->u.three[1]);
 			    Ops[1] = convertOperand(func, I32Ty, inst->u.three[2]);
-//			    Ops[1] = Builder.CreateTrunc(Ops[1], I32Ty);
+			    Ops[1] = GEPOperand(Ops[1]);
 			    if (!createGEP(inst->dest, V, Ops, Ops+2))
 				return false;
 			    break;
@@ -1209,7 +1240,7 @@ public:
 			    Value *V = convertOperand(func, SrcTy, inst->u.ops.ops[1]);
 			    for (unsigned a=2;a<inst->u.ops.numOps;a++) {
 				Value *Op = convertOperand(func, I32Ty, inst->u.ops.ops[a]);
-//				Op = Builder.CreateTrunc(Op, I32Ty);
+				Op = GEPOperand(Op);
 				Idxs.push_back(Op);
 			    }
 			    if (!createGEP(inst->dest, V, Idxs.begin(), Idxs.end()))
@@ -1669,6 +1700,8 @@ int cli_bytecode_prepare_jit(struct cli_all_bc *bcs)
 	addFunctionProtos(&CF, EE, M);
 
 	FunctionPassManager OurFPM(M);
+	M->setDataLayout(EE->getTargetData()->getStringRepresentation());
+	M->setTargetTriple(sys::getHostTriple());
 	// Set up the optimizer pipeline.  Start with registering info about how
 	// the target lays out data structures.
 	OurFPM.add(new TargetData(*EE->getTargetData()));