/// <summary>
/// Transpiles a method to replace instances of one constant value with another.
///
/// Note that values of type byte, short, char, and bool are also represented with "i4"
/// constants which can be targeted by this method.
/// </summary>
/// <param name="method">The method to patch.</param>
/// <param name="oldValue">The old constant to remove.</param>
/// <param name="newValue">The new constant to replace.</param>
/// <param name="all">true to replace all instances, or false to replace the first
/// instance (default).</param>
/// <returns>A transpiled version of that method which replaces instances of the first
/// constant with that of the second.</returns>
public static TranspiledMethod ReplaceConstant(TranspiledMethod method, int oldValue,
int newValue, bool all = false)
{
int replaced = 0;
bool quickCode = oldValue >= -1 && oldValue <= 8;
var qc = OpCodes.Nop;
if (method == null)
{
throw new ArgumentNullException(nameof(method));
}
// Quick test for the opcode on the shorthand forms
if (quickCode)
{
qc = PTranspilerTools.LOAD_INT[oldValue + 1];
}
foreach (var inst in method)
{
var instruction = inst;
var opcode = instruction.opcode;
object operand = instruction.operand;
if ((opcode == OpCodes.Ldc_I4 && (operand is int ival) && ival == oldValue) ||
(opcode == OpCodes.Ldc_I4_S && (operand is byte bval) && bval ==
oldValue) || (quickCode && qc == opcode))
{
// Replace instruction if first instance, or all to be replaced
if (all || replaced == 0)
{
PTranspilerTools.ModifyLoadI4(instruction, newValue);
}
replaced++;
}
yield return(instruction);
}
}
/// <summary>
/// Transpiles a method to replace calls to the specified victim methods with
/// replacement methods, altering the call type if necessary.
///
/// Each key to value pair must meet the criteria defined in
/// ReplaceMethodCall(TranspiledMethod, MethodInfo, MethodInfo).
/// </summary>
/// <param name="method">The method to patch.</param>
/// <param name="translation">A mapping from the old method calls to replace, to the
/// new method calls to use instead.</param>
/// <returns>A transpiled version of that method that replaces or removes all calls
/// to the specified methods.</returns>
/// <exception cref="ArgumentException">If any of the new methods' argument types do
/// not exactly match the old methods' argument types.</exception>
public static TranspiledMethod ReplaceMethodCall(TranspiledMethod method,
IDictionary <MethodInfo, MethodInfo> translation)
{
if (method == null)
{
throw new ArgumentNullException(nameof(method));
}
if (translation == null)
{
throw new ArgumentNullException(nameof(translation));
}
// Sanity check arguments
int replaced = 0;
foreach (var pair in translation)
{
var victim = pair.Key;
var newMethod = pair.Value;
if (victim == null)
{
throw new ArgumentNullException(nameof(victim));
}
if (newMethod != null)
{
PTranspilerTools.CompareMethodParams(victim, victim.GetParameterTypes(),
newMethod);
}
else if (victim.ReturnType != typeof(void))
{
throw new ArgumentException("Cannot remove method {0} with a return value".
F(victim.Name));
}
}
foreach (var instruction in method)
{
var opcode = instruction.opcode;
MethodInfo target;
if ((opcode == OpCodes.Call || opcode == OpCodes.Calli || opcode == OpCodes.
Callvirt) && translation.TryGetValue(target = instruction.operand as
MethodInfo, out MethodInfo newMethod))
{
if (newMethod != null)
{
// Replace with new method
instruction.opcode = newMethod.IsStatic ? OpCodes.Call :
OpCodes.Callvirt;
instruction.operand = newMethod;
yield return(instruction);
}
else
{
// Pop "this" if needed
int n = target.GetParameters().Length;
if (!target.IsStatic)
{
n++;
}
// Pop the arguments off the stack
instruction.opcode = (n == 0) ? OpCodes.Nop : OpCodes.Pop;
instruction.operand = null;
yield return(instruction);
for (int i = 0; i < n - 1; i++)
{
yield return(new CodeInstruction(OpCodes.Pop));
}
}
replaced++;
}
else
{
yield return(instruction);
}
}
#if DEBUG
if (replaced == 0)
{
if (translation.Count == 1)
{
// Diagnose the method that could not be replaced
var items = new KeyValuePair <MethodInfo, MethodInfo> [1];
translation.CopyTo(items, 0);
MethodInfo from = items[0].Key, to = items[0].Value;
PUtil.LogWarning("No method calls replaced: {0}.{1} to {2}.{3}".F(
from.DeclaringType.FullName, from.Name, to.DeclaringType.FullName,
to.Name));
}
else
{
PUtil.LogWarning("No method calls replaced (multiple replacements)");
}
}
#endif
}
public static void LogAllExceptions()
{
PUtil.LogWarning("PLib in mod " + Assembly.GetCallingAssembly().GetName()?.Name +
" is logging ALL unhandled exceptions!");
PTranspilerTools.LogAllExceptions();
}
public static void LogAllFailedAsserts()
{
PUtil.LogWarning("PLib in mod " + Assembly.GetCallingAssembly().GetName()?.Name +
" is logging ALL failed assertions!");
PTranspilerTools.LogAllFailedAsserts();
}
/// <summary>
/// Checks to see if an instruction opcode is a branch instruction.
/// </summary>
/// <param name="opcode">The opcode to check.</param>
/// <returns>true if it is a branch, or false otherwise.</returns>
public static bool IsConditionalBranchInstruction(this OpCode opcode)
{
return(PTranspilerTools.IsConditionalBranchInstruction(opcode));
}
