Same IL code, different output - how is it possible?
- by Hali
When I compile this code with mono (gmcs) and run it, it outputs -1 (both with mono and .Net framework).
When I compile it with VS (csc), it outputs -1 when I run it with mono, and 0 when I run it with the .Net framework.
The code in question is:
using System;
public class Program {
public static void Main() {
Console.WriteLine(string.Compare("alo\0alo\0", "alo\0alo\0\0", false, System.Globalization.CultureInfo.InvariantCulture));
}
}
Compiled with VS:
.method public hidebysig static void Main() cil managed
{
.entrypoint
// Code size 29 (0x1d)
.maxstack 8
IL_0000: nop
IL_0001: ldstr bytearray (61 00 6C 00 6F 00 00 00 61 00 6C 00 6F 00 00 00 ) // a.l.o...a.l.o...
IL_0006: ldstr bytearray (61 00 6C 00 6F 00 00 00 61 00 6C 00 6F 00 00 00 // a.l.o...a.l.o...
00 00 )
IL_000b: ldc.i4.0
IL_000c: call class [mscorlib]System.Globalization.CultureInfo [mscorlib]System.Globalization.CultureInfo::get_InvariantCulture()
IL_0011: call int32 [mscorlib]System.String::Compare(string,
string,
bool,
class [mscorlib]System.Globalization.CultureInfo)
IL_0016: call void [mscorlib]System.Console::WriteLine(int32)
IL_001b: nop
IL_001c: ret
} // end of method Program::Main
Compiled with mono:
.method public hidebysig static void Main() cil managed
{
.entrypoint
// Code size 27 (0x1b)
.maxstack 8
IL_0000: ldstr bytearray (61 00 6C 00 6F 00 00 00 61 00 6C 00 6F 00 00 00 ) // a.l.o...a.l.o...
IL_0005: ldstr bytearray (61 00 6C 00 6F 00 00 00 61 00 6C 00 6F 00 00 00 // a.l.o...a.l.o...
00 00 )
IL_000a: ldc.i4.0
IL_000b: call class [mscorlib]System.Globalization.CultureInfo [mscorlib]System.Globalization.CultureInfo::get_InvariantCulture()
IL_0010: call int32 [mscorlib]System.String::Compare(string,
string,
bool,
class [mscorlib]System.Globalization.CultureInfo)
IL_0015: call void [mscorlib]System.Console::WriteLine(int32)
IL_001a: ret
} // end of method Program::Main
The only difference is the two extra NOP instructions in the VS version.
How is it possible?
