/// <summary>
/// Parses compile time constants from the specified <paramref name = "offset" /> until it encounters an instruction that is not compile-time-constant. Returns the compile time values in the order they appear in the code (the "right" order).
/// </summary>
/// <param name = "instructions">The code to parse from.</param>
/// <param name = "localVariableMapping">The local variable mapping to apply when confronted with index-instructions (e.g., <code>ldloci</code>)</param>
/// <param name = "offset">The offset of the first possible compile time constant.</param>
/// <param name="cache">The cache to use. See <see cref="StackContext"/> or <see cref="Module"/> on how to get one.</param>
/// <param name="internalModule">The module that contains the instructions.</param>
/// <returns>the compile time values in the order they appear in the code (the "right" order).</returns>
public static CompileTimeValue[] ParseSequenceReverse(IList<Instruction> instructions,
IDictionary<int, string> localVariableMapping, int offset, CentralCache cache, ModuleName internalModule)
{
var compileTimeValues = new LinkedList<CompileTimeValue>();
CompileTimeValue compileTimeValue;
while (0 <= offset &&
TryParse(instructions[offset--], localVariableMapping, cache, internalModule, out compileTimeValue))
compileTimeValues.AddFirst(compileTimeValue);
return compileTimeValues.ToArray();
}
/// <summary>
/// Tries to parse the supplied instruction into a compile time value.
/// </summary>
/// <param name = "instruction">The instruction to parse.</param>
/// <param name = "localVariableMapping">The local variable mapping to apply when confronted with index-instructions (e.g., <code>ldloci</code>)</param>
/// <param name="cache">The cache to use for module names and entity references.</param>
/// <param name="internalModule"> The module the instruction lives in. Necessary to create absolute entity references.</param>
/// <param name = "compileTimeValue">The parsed compile time value, if parsing was successful; undefined otherwise</param>
/// <returns>True if parsing was successful; false otherwise</returns>
public static bool TryParse(Instruction instruction, IDictionary<int, string> localVariableMapping, CentralCache cache, ModuleName internalModule, out CompileTimeValue compileTimeValue)
{
var argc = instruction.Arguments;
switch (instruction.OpCode)
{
case OpCode.ldc_int:
compileTimeValue.Interpretation = CompileTimeInterpretation.Int;
compileTimeValue.Value = (int?) argc;
return true;
case OpCode.ldc_real:
compileTimeValue = default(CompileTimeValue);
return false;
case OpCode.ldc_bool:
compileTimeValue.Interpretation = CompileTimeInterpretation.Bool;
compileTimeValue.Value = argc != 0;
return true;
case OpCode.ldc_string:
compileTimeValue.Interpretation = CompileTimeInterpretation.String;
compileTimeValue.Value = instruction.Id;
return true;
case OpCode.ldc_null:
compileTimeValue.Interpretation = CompileTimeInterpretation.Null;
compileTimeValue.Value = null;
return true;
case OpCode.ldr_loc:
compileTimeValue.Interpretation =
CompileTimeInterpretation.LocalVariableReference;
compileTimeValue.Value = cache[EntityRef.Variable.Local.Create(instruction.Id)];
return true;
case OpCode.ldr_loci:
string id;
if (!localVariableMapping.TryGetValue(argc, out id) || id == null)
goto default;
compileTimeValue.Interpretation =
CompileTimeInterpretation.LocalVariableReference;
compileTimeValue.Value = cache[EntityRef.Variable.Local.Create(id)];
return true;
case OpCode.ldr_glob:
compileTimeValue.Interpretation =
CompileTimeInterpretation.GlobalVariableReference;
compileTimeValue.Value = cache[EntityRef.Variable.Global.Create(instruction.Id, instruction.ModuleName ?? internalModule)];
return true;
case OpCode.ldr_func:
compileTimeValue.Interpretation = CompileTimeInterpretation.FunctionReference;
compileTimeValue.Value = cache[EntityRef.Function.Create(instruction.Id, instruction.ModuleName ?? internalModule)];
return true;
case OpCode.ldr_cmd:
compileTimeValue.Interpretation = CompileTimeInterpretation.CommandReference;
compileTimeValue.Value = cache[EntityRef.Command.Create(instruction.Id)];
return true;
case OpCode.ldr_app:
compileTimeValue = default(CompileTimeValue);
return false;
case OpCode.ldr_eng:
compileTimeValue = default(CompileTimeValue);
return false;
case OpCode.ldr_type:
compileTimeValue = default(CompileTimeValue);
return false;
default:
compileTimeValue = default(CompileTimeValue);
return false;
}
}
