This question got me wondering about where the concrete implementaiton of a generic method actually comes into existence. I've tried the google but am not coming up with the right search.
If we take this simple example:
class Program
{
public static T GetDefault<T>()
{
return default(T);
}
static void Main(string[] args)
{
int i = GetDefault<int>();
double d = GetDefault<double>();
string s = GetDefault<string>();
}
}
in my head I've always assumed that at some point it results in an implementation with the 3 necessary concrete implementations such that, in naive pseudo mangling, we would have this logical concrete implementaiton where the specific types used result in the correct stack allocations etc.
class Program
{
static void Main(string[] args)
{
int i = GetDefaultSystemInt32();
double d = GetDefaultSystemFloat64();
string s = GetDefaultSystemString();
}
static int GetDefaultSystemInt32()
{
int i = 0;
return i;
}
static double GetDefaultSystemFloat64()
{
double d = 0.0;
return d;
}
static string GetDefaultSystemString()
{
string s = null;
return s;
}
}
Looking at the IL for the generic program it is still expressed in terms of generic types:
.method public hidebysig static !!T GetDefault<T>() cil managed
{
// Code size 15 (0xf)
.maxstack 1
.locals init ([0] !!T CS$1$0000,
[1] !!T CS$0$0001)
IL_0000: nop
IL_0001: ldloca.s CS$0$0001
IL_0003: initobj !!T
IL_0009: ldloc.1
IL_000a: stloc.0
IL_000b: br.s IL_000d
IL_000d: ldloc.0
IL_000e: ret
} // end of method Program::GetDefault
So how and at what point is it decided that an int, and then a double and then a string have to be allocated on the stack and returned to the caller? Is this an operation of the JIT process? Am I looking at this in the completely wrong light?
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