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Mantis#3187. Thank you kindly, DoranZemlja for a patch that:

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Adds a warning for an LSL construct that exploits a
popular list memory saving hack.
This commit is contained in:
Charles Krinke
2009-02-23 02:43:51 +00:00
parent 20eb8e54ac
commit 08c76989a7
6 changed files with 169 additions and 0 deletions
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77
OpenSim/Region/ScriptEngine/Shared/CodeTools/CSCodeGenerator.cs
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@@ -40,6 +40,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.CodeTools
private int m_braceCount; // for indentation
private int m_CSharpLine; // the current line of generated C# code
private int m_CSharpCol; // the current column of generated C# code
private List<string> m_warnings = new List<string>();
/// <summary>
/// Creates an 'empty' CSCodeGenerator instance.
@@ -152,6 +153,23 @@ namespace OpenSim.Region.ScriptEngine.Shared.CodeTools
return retstr;
}
/// <summary>
/// Get the set of warnings generated during compilation.
/// </summary>
/// <returns></returns>
public string[] GetWarnings()
{
return m_warnings.ToArray();
}
private void AddWarning(string warning)
{
if (!m_warnings.Contains(warning))
{
m_warnings.Add(warning);
}
}
/// <summary>
/// Recursively called to generate each type of node. Will generate this
/// node, then all it's children.
@@ -446,6 +464,9 @@ namespace OpenSim.Region.ScriptEngine.Shared.CodeTools
{
string retstr = String.Empty;
List<string> identifiers = new List<string>();
checkForMultipleAssignments(identifiers, a);
retstr += GenerateNode((SYMBOL) a.kids.Pop());
retstr += Generate(String.Format(" {0} ", a.AssignmentType), a);
foreach (SYMBOL kid in a.kids)
@@ -454,6 +475,62 @@ namespace OpenSim.Region.ScriptEngine.Shared.CodeTools
return retstr;
}
// This code checks for LSL of the following forms, and generates a
// warning if it finds them.
//
// list l = [ "foo" ];
// l = (l=[]) + l + ["bar"];
// (produces l=["foo","bar"] in SL but l=["bar"] in OS)
//
// integer i;
// integer j;
// i = (j = 3) + (j = 4) + (j = 5);
// (produces j=3 in SL but j=5 in OS)
//
// Without this check, that code passes compilation, but does not do what
// the end user expects, because LSL in SL evaluates right to left instead
// of left to right.
//
// The theory here is that producing an error and alerting the end user that
// something needs to change is better than silently generating incorrect code.
private void checkForMultipleAssignments(List<string> identifiers, SYMBOL s)
{
if (s is Assignment)
{
Assignment a = (Assignment)s;
string newident = null;
if (a.kids[0] is Declaration)
{
newident = ((Declaration)a.kids[0]).Id;
}
else if (a.kids[0] is IDENT)
{
newident = ((IDENT)a.kids[0]).yytext;
}
else if (a.kids[0] is IdentDotExpression)
{
newident = ((IdentDotExpression)a.kids[0]).Name; // +"." + ((IdentDotExpression)a.kids[0]).Member;
}
else
{
AddWarning(String.Format("Multiple assignments checker internal error '{0}' at line {1} column {2}.", a.kids[0].GetType(), ((SYMBOL)a.kids[0]).Line - 1, ((SYMBOL)a.kids[0]).Position));
}
if (identifiers.Contains(newident))
{
AddWarning(String.Format("Multiple assignments to '{0}' at line {1} column {2}; results may differ between LSL and OSSL.", newident, ((SYMBOL)a.kids[0]).Line - 1, ((SYMBOL)a.kids[0]).Position));
}
identifiers.Add(newident);
}
int index;
for (index = 0; index < s.kids.Count; index++)
{
checkForMultipleAssignments(identifiers, (SYMBOL) s.kids[index]);
}
}
/// <summary>
/// Generates the code for a ReturnStatement node.
/// </summary>