Specialize operands depending on bitwidth.

Author: Török Edvin

libclamav/bytecode.c

@@ -482,6 +482,16 @@ static int parseBB(struct cli_bc *bc, unsigned func, unsigned bb, unsigned char
 	    case OP_TRUNC:
 		inst.u.cast.source = readOperand(bcfunc, buffer, &offset, len, &ok);
 		inst.u.cast.mask = bcfunc->types[inst.u.cast.source];
+		if (inst.u.cast.mask == 1)
+		    inst.u.cast.size = 0;
+		else if (inst.u.cast.mask <= 8)
+		    inst.u.cast.size = 1;
+		else if (inst.u.cast.mask <= 16)
+		    inst.u.cast.size = 2;
+		else if (inst.u.cast.mask <= 32)
+		    inst.u.cast.size = 3;
+		else if (inst.u.cast.mask <= 64)
+		    inst.u.cast.size = 4;
 		/* calculate mask */
 		if (inst.opcode != OP_SEXT)
 		    inst.u.cast.mask = inst.u.cast.mask != 64 ?
@@ -533,6 +543,15 @@ static int parseBB(struct cli_bc *bc, unsigned func, unsigned bb, unsigned char
 		inst.type = bcfunc->types[inst.u.binop[0]];
 		break;
 	}
+	inst.interp_op = inst.opcode*5;
+	if (inst.type > 1 && inst.type <= 8)
+	    inst.interp_op += 1;
+	else if (inst.type <= 16)
+	    inst.interp_op += 2;
+	else if (inst.type <= 32)
+	    inst.interp_op += 3;
+	else if (inst.type <= 64)
+	    inst.interp_op += 4;
 	BB->insts[BB->numInsts++] = inst;
     }
     if (bb+1 == bc->funcs[func].numBB) {
@@ -636,6 +655,7 @@ int cli_bytecode_run(const struct cli_bc *bc, struct cli_bc_ctx *ctx)
     func.numValues = 1;
 
     inst.opcode = OP_CALL_DIRECT;
+    inst.interp_op = OP_CALL_DIRECT*5;
     inst.dest = func.numArgs;
     inst.type = 0;/* TODO: support toplevel functions with return values */
     inst.u.ops.numOps = ctx->numParams;

libclamav/bytecode_priv.h

@@ -47,12 +47,16 @@ struct cli_bc_value {
 };
 
 struct cli_bc_cast {
-    operand_t source;
     uint64_t mask;
+    operand_t source;
+    uint8_t size;/* 0: 1-bit, 1: 8b, 2: 16b, 3: 32b, 4: 64b */
 };
+
+typedef uint8_t interp_op_t;
 struct cli_bc_inst {
     enum bc_opcode opcode;
     uint16_t type;
+    interp_op_t interp_op;/* opcode for interpreter */
     operand_t dest;
     union {
 	operand_t unaryop;