(float)"1.1754944e-38" is != 0
(float)"1.1754943e-38" is == 0
Yet, 1.1754944e-38 == 1.1754943e-38.
The fix is to perform the operations as doubles, and convert to F32 *after* comparing the denormal range.
LSO allows this. The compiler does too, but it chokes in RAIL.
This affected a test, which has been adjusted too.
Untyped lazy list elements can no longer be used in isolation in expression lists (including FOR initializator and iterator).
Also rename the terribly named 'self.forbidlabels' to 'self.optenabled' which is more descriptive.
This extremely uncommon coding pattern was becoming a hell to support. It has caused many bugs in past that need them being treated as special cases.
Getting rid of the possibility entirely seems like the best approach.
It's still supported if the code is not to be optimized (e.g. with --pretty).
While not strictly a bug because it would be caught later in the function (it passes the tests either way), it made me nervous to leave a dangling NextToken().
This may cause more trouble than it's worth, but it's how LSL behaves and one of our objectives is to document the darker corners of LSL. Mono chokes at the RAIL postprocessing stage, not in compilation proper. LSO chokes at runtime for string, key and list, and works fine for the other types.
That was long overdue. Obviously, this is a large commit.
The new nr (node record) class has built-in dump capabilities, rather than using print_node().
SEF always exists now, and is a boolean, rather than using the existence of SEF as the flag. This was changed for sanity. However, other flags like 'X' are still possibly absent, and in some cases the absence itself has meaning (in the case of 'X', its absence means that the node has not yet been analyzed).
Similarly, an event is distinguished from a UDF by checking for the existence of the 'scope' attribute. This trick works because events are not in the symbol table therefore they have no scope. But this should probably be changed in future to something more rational and faster.
A few minor bugfixes were applied while going through the code.
- Some tabs used as Unicode were written as byte strings. Add the u'\t' prefix.
- After simplifying a%1 -> a&0, fold again the node and return. It's not clear why it didn't return, and whether it depended on subsequent passes (e.g. after DCR) for possibly optimizing out the result. Now we're sure.
- A few places lacked a SEF declaration.
- Formatting changes to split lines that spilled the margin.
- Some comment changes.
- Expanded lazy_list_set definition while adapting it to object format. The plan was to re-compress it after done, but decided to leave it in expanded form.
- Added a few TODOs & FIXMEs, resisting the temptation to fix them in the same commit:
- TODO: ~-~-~-expr -> expr + -3.
- FIXME: Now that we have CompareTrees, we can easily check if expr + -expr cancels out and remove a TODO. Low-hanging fruit.
- TODO: Check what we can do when comparing non-SEF and non-CONST values in '>' (current code relies on converting '>' to '<' for applying more optimizations, but that may miss some opportunities).
- FIXME: Could remove one comparison in nt == '&&' or nt == '||'. Low-hanging fruit.
-a == -b -> a == b
If both a and b either are constants or have a minus sign, negate both.
!(a - b) can be optimized to a == b.
!(a + b) can be optimized to -a == b, relying on the first optimization to remove redundant minus signs.
int != int was not properly optimized, because the != was transformed into the equivalent !(int == int) at an earlier stage. Fixed.
!(a ^ b) can be optimized to a == b, so do it.
Our previous fix was incomplete, because it failed to detect the last IF in a chain of ELSE IFs. For example:
if (a == 2) llDie(); else if (a) llDie(); else if (a == 3) llDie();
That would be transformed by the IF swapper into:
if (a ^ 2)
if (a)
llDie();
else if (a == 3)
llDie();
else
llDie();
Note that the last 'else' would bind to the last 'if', not to the first one. So the condition is actually like this:
child[1] of an 'if' statement needs to be guarded in {} if the 'else' may belong to the wrong 'if'.
It will belong to the wrong 'if' if child[1] is a (possibly empty) chain of 'if {whatever} else ...', followed by an 'if' without 'else', that is:
if (cond) stmt;
(which was what our previous check did), but also e.g.:
if (cond) stmt; else if (cond) stmt; else if (cond) stmt;
which we neglected to consider in our previous fix.
Since our syntax extensions transform the source at parse time, all syntax extensions are disabled. The optimizations are disabled too, as it doesn't make sense to prettify and optimize at the same time (the optimizer would remove the constants that we're trying to keep).
Addresses #4 in a more user-friendly way.
097c054 introduced a bug that we hadn't caught until now.
In some occasions, it could swap nested conditions in such a way that the 'else' of the outer statement was made to belong to the inner one, like this:
if (a)
if (b)
stuff;
else
stuff;
That is of course parsed with the 'else' belonging to if(b).
Fix implemented at output time, by detecting 'if(a) stmt; else y;' with stmt being an 'if' without 'else', and wrapping the stmt in {} like this: 'if(a){if(b) x;} else y;'. This has some similarity with parenthesis addition.
But the fix has the corner case that, since {} hides visibility of labels, when the inner 'if' has a label as direct child, it can't be swapped lest the label becomes out of scope. So these cases are detected and skipped in the constant folding module.
In the case of 'if(cond);', we transform it to 'cond;', but we forgot to wrap the cond in an EXPR node as required. Fixed too.
Reorganize into different statements with early return.
Add constants, unary operators and binary operators. Check if operator is commutative and check with operands swapped when so.
Constant equality is somewhat sketchy at the moment: just compare the values with Python's ==.
Implements another TODO.
There was a TODO about a new counter per scope, but that makes no sense. The renamer only acts on global variables, global function and parameter names, state names, and event parameters. We're already restarting the counters at every function, which is the closest to what that TODO was about.
This has been a TODO item for long. Now that we have lsllastpass, it's actually easy to implement.
Adds an LSLTypeDefaults dictionary to lslcommon, just in case the state-changing function returns a value and we need to insert a return statement.
We've also added subtree-local info to lsllastpass (lost when we return to the parent after visiting a subtree).
This fixes a bug where naked switch statements could appear as a result of optimization, and cause the compilation to fail.
Still somewhat messy, but still reported as soon as it can be detected.
If an ELSE token is detected at the top level, for example, the error position will be rewound to the state change and reported there.
This means that in this situation:
x()
{
if (1)
{
state default;
x(2);
}
else ;
}
default{timer(){}}
an error will be reported in x(2), because the ELSE hasn't been found at that point, therefore the state change statement isn't found to be at fault yet.
However, in this case:
x()
{
if (1)
state default;
else
x(2);
}
default{timer(){}}
the error WILL be reported at the state change statement.
This commit also changes the position where the exception is reported, to be at the STATE token. As an inconsequential side effect, EParseCantChangeState takes precedence over undefined identifiers, in case the state change is to an undefined state, but only in cases where it can be immediately detected.
if (!cond) X; else Y; -> if (cond) Y; else X;
if (int1 == int2) X; else Y; -> if (int1 ^ int2) Y; else X;
When 'cond' is of a type other than 'key': if (cond) ; else X; -> if (!cond) X; (this required changing if(str) to its compiled equivalent if(!(str == "")), so that 'cond' is always either key or integer).
if (cond) ; -> cond; and folds it as a statement, which may eliminate it if it's SEF. This is done after eliminating 'else ;' so that it also optimizes 'if (cond) ; else ;' the same way.
This removes a TODO item.
Allows detection of empty events, for example, even if they have labels.
Also, it is OK if there's a label inserted in a nested {}; that case wasn't contemplated.
Gives us a few more opportunities for catching single-letter identifiers.
UsedNames was not restarted. It's unlikely that this had any detrimental effect on optimization, and it was certainly safe to not restart it. But it looks more correct like this.
When a constant was negative internally, it was output with the sign included. The code was not prepared to handle this, and could therefore cause double minus signs. For example, -2147483648 was output as --2147483648, and -4294967296 was output as --1.
Fixed by adding a space for floats, and by translating the number to the range 2147483648..4294967295 for integers (hex would have worked just as well).
The comment was wrong anyway. If one side changes x and the other side uses x, then order is still important, no matter whether one side is SEF.
But the reversal is safe when one side is a constant, so we still perform it, to enable optimization of some important cases.
For floats:
When const >= function.max, comparisons of function > const always yield FALSE.
When const < function.min, comparisons of function > const always yield TRUE.
When const > function.max, comparisons of function < const always yield TRUE.
When const <= function.min, comparisons of function < const always yield FALSE.
For integers:
When min = -1, cond(function > -1) is the same as cond(!~function).
When min = -1, cond(function < 0) is the same as cond(~function).
To implement the above, we got rid of the cond(x < 0) -> cond(x & 0x80000000) optimization, which has caused more trouble than it has solved for just 1 byte gain.
When min = 0, cond(function > 0) is the same as cond(function).
When min = 0, cond(function < 1) is the same as cond(!function).
Similar expressions can be obtained for max in [-1, 0], but it's not worth it, as there are no functions with -1 as maximum, and the ones with max=0 also have min=0 (always return 0).
We had dormant code to check for boolean-ness of functions, which is now active. But it didn't cover all possible booleans. Now it does.
An idea for the future is to associate ranges to expressions, and attach them to calculable functions. For example, (integer)llFrand(2) could be resolved to a boolean.
This solves a long-standing issue where we needed more data about LSL functions than just whether it's side-effect-free.
There's still some debug code, which is kept for history purposes.
- Separate library loading code into a new module. parser.__init__() no longer loads the library; it accepts (but does not depend on) a library as a parameter.
- Add an optional library argument to parse(). It's no longer mandatory to create a new parser for switching to a different builtins or seftable file.
- Move warning() and types from lslparse to lslcommon.
- Add .copy() to uses of base_keywords, to not rely on it being a frozen set.
- Adjust the test suite.
They were returning TOUCH_INVALID_TEXCOORD for num <= idx <= 15 in detection events which were not touch events. That is incorrect.
Now it correctly returns:
- ZERO_VECTOR when idx < 0 or idx > 15 or the event is known not to be a detection event.
- TOUCH_INVALID_TEXCOORD when idx == 0 and the event is known to be a detection event that is not a touch event.
- Raises ELSLCantCompute otherwise.
We oversought that the optimization that 8d33746 applied was already present, so no need to duplicate it.
A better place for handling '|' was under the code that already did so. No functionality change involved.
CleanNode was too greedy, because children of global declarations (particularly lists) are not marked executable. Make a special case for them and don't recurse, since what matters is whether the declaration itself is executed. Its contents can't be cleaned up.
In Python, NaN*Indet in any order returns the second operand, and NaN/Indet in any order returns the first operand. LSL consistently returns NaN in all cases.
The force type functions ff(), fi(), fs()... should normally trigger ELSLTypeMismatch when the input is not in the expected range of types, rather than ELSLInvalidType, which is reserved for the case where the type is not a valid LSL type.
It can't be done always: flag1 and flag2 must be nonzero powers of two. In that case, we can transform it to:
!~(x|~(flag1|flag2)) = !~(x|constant)
The -2147483648 case has trouble with the sign hack detector and I couldn't trigger it.
Rather than assert that the types are correct, use the force type functions on the parameters:
ff, fk, fs, q2f, v2f, and the new fi, fl.
These functions have also been modified to ensure that the input type supports an implicit typecast to the target type and perform it, or emit ELSLInvalidType otherwise, rather than an assertion failure. fl in particular returns the original list if it isn't changed, or a copy if it is.
A couple bugs were found in testfuncs.py as a result, which have been fixed as well. A test has been added to ensure that the exception that caught these bugs remains in place.
The isxxxx functions are no longer necessary, so they are removed. Same goes for the painful cast handling process in foldconst, which was basically performing this task, and not necessarily well.
This approach is much more robust and should have been used since the beginning, but I didn't figure it out then.
Also simplify and fix the matching expression for #line (gcc inserts numeric flags at the end).
It still has many problems. It's O(n^2). It's calculated at every EParse, and EParse can be triggered and ignored while scanning vectors or globals. UniConvScript doesn't read #line at all, thus failing to report a meaningful input line. But at least it's a start.
ReportError() needed to account for terminal encodings that don't support the characters being printed. It was also reporting an inaccurate column number and its corresponding marker position, because the count was in bytes, not in characters, so that has been fixed.
Now EParse.__init__() calls a new function GetErrLineCol() that calculates the line and column corresponding to an error position.
The algorithm for finding the start of the line has also been changed in both ReportError() and EParse.__init__(); as a result, function fieldpos() has been removed.
The exception's lno and cno fields have been changed to be 1-based, rather than 0-based.
Thanks to @Jomik for the report. Fixes#5.
lslcleanup: Variables renamed, order changed, comments added.
Other changes: remove semicolon at end of sentence, use self.Cast instead of creating a CAST node on the fly.
That's exactly what 'cond' is for. Things like a loop with a constant zero vector condition should be recognized.
It was correct before just by chance, because FoldCond currently transforms a constant node into an integer node, but let's not rely on that.
When the index is good, on non-touch functions:
- llDetectedTouchFace returns -1.
- llDetectedTouchST and llDetectedTouchUV return TOUCH_INVALID_TEXCOORD.
We were returning 0 and ZERO_VECTOR respectively.
No other functional changes. This required quite some reorganization affecting many files. As a side effect, PythonType2LSL and LSLType2Python aren't duplicate anymore.
- Resolve for lists that aren't constants, but that are SEF, and reference a constant element, e.g. llList2String([llGetKey(), 5], 1) -> 5.
- Make it work with invalid conversions, if they are SEF.
- Simplify invalid conversions when the list argument is a llGetObjectDetails call and SEF.
- Simplify llList2String(llGetObjectDetails(id, [single_element]), 0) (or -1) to (string)llGetObjectDetails...; same with llList2Key and llList2Integer, converting it to (integer)((string)llGetObjectDetails...).
- Add TODO item to do it similarly for llGet[Link]PrimitiveParams.
Adds auxiliary functions to return a node or constant from a list in any of its forms, its length, and a constant for a node or constant.
Adds some utility members for LSL<->Python type conversion (one of them duplicated from lslparse.py).
Needs maintenance of the types returned by llGetObjectDetails.
if(list!=[]) is always better than if(list), which compiles to if(!(list==[])).
if(float) can't be optimized, but it is equivalent to if(float!=0.0) which can. Same for vector, rotation.
It was failing with a && b && c where a, b, c were known to be bools. It managed to simplify them to a & b & -c but that's not optimal.
Now it recurses on some operators that may return bool when used with bool operands: &, |, ^, * (in the case of &, it's bool if either operand is; for the rest, it's bool if both are). As a result, the above now simplifies to a & b & c, which is optimal.
Adds a new EParseInvalidBrkContArg exception. Previously it raised EParseInvalidBreak or EParseInvalidCont, whose text was misleading for this type of error.
We were letting Python typecast, and that causes the wrong result on Windows. Return the correct result explicitly when "nan" is found in the string.
Also, small reformatting of an else if -> elif.
The reusable names table was being emptied as identifiers were used. This was sub-optimal for function parameters, because new identifiers would need to be created when exhausted.
Reset the reusable names list to a saved copy every time a new parameter list is started, in a similar fashion to what we did with the sequentially generated identifiers.
Rather than using tuples for set belonging, use a frozen set. That eliminates the need to separate them by lengths.
Also, 'Pop' is not a reserved word. It's perfectly valid as a possible substitution identifier, so allow it. If used, it will go to the used words anyway and thus will be skipped by the sequential name generator.
The former ones don't match LSL's behaviour, in particular llRotBetween(<1,0,0>,<-1,0,0>) should return <0,0,1,0> but it didn't. Fix by using an algorithm that is closer to the one used by the sim.
We had too much precision. In LSL, llRound(0.49999997) gives 1, not 0, because the loss of precision after adding 0.5 to that makes the result 1. Fixed by converting to F32 prior to flooring.
LL's algorithm for llEuler2Rot involves calculating a rotation matrix from the Eulers, then transforming the rotation matrix to quaternion. This generates sign discrepancies with our direct quaternion calculation algorithm.
Fixed by making only the necessary calculations to find the correct sign. Unfortunately, they are still heavy (notably, six more trig functions).
Mainly, the input quaternion wasn't being normalized prior to using it for calculations, and that broke compatibility. But even then, sometimes the arc sine of a value greater than 1 could be calculated, so we clamp it.
For all zeros input, the result was <1,0,0,0> but we were producing <0,0,0,.5> because the first branch was taken. Fixed.
We forgot to take the square root when calculating the magnitude of the quaternion while normalizing. Fixed.
Use qnz instead of special casing.
LSL behaves as if it was ZERO_ROTATION instead, so we fix it by creating a function that returns ZERO_ROTATION when given <0,0,0,0>. Use it for llRot2{Fwd,Left,Up} as well.
llAbs(-2147483648) raises this:
System.OverflowException: Value is too small.
at System.Math.Abs (Int32 value) [0x00000] in <filename unknown>:0
at LindenLab.SecondLife.Library.llAbs (Int32 i) [0x00000] in <filename unknown>:0
So it's actually not computable. In LSO it returns -2147483648, though.
llGetSubString and llList2List could produce output longer than the input for some params. Fix that, and join the functions into one unique function for uniformity. Also, get rid of the special case of empty elements, because it can be treated properly by the general case, and it's not so common as to merit special attention.
When the input was of the form e.g. "%4%40", the second "%" was erroneously starting another quoted character. LSL doesn't behave that way: parsing resumes without starting another quoted character. Disturbingly, the expected result in the corresponding test was wrong. Fixed both the test case and the code to match actual LSL behaviour.
llBase64ToString hid another surprise: characters in range from U+0000 to U+001F are substituted by "?" except for tabs (\x09), form feeds (\x0A), shift ins (\x0F) and unit separators (\x1F), which were kept verbatim. So, mimic this behaviour.
When a function was successfully applied, the resulting constant node was not marked as side effect-free. This could potentially lead to poor optimization.
Testing shows that AGENT_LIST_xxx values are not used as a bitfield, but as an enum. There are only three possible valid values. Check only those three.
Lists can't contain lists at runtime, but they can at parse time, so the optimizer must behave properly when handling nested lists. And it didn't, because it neglected to preserve the previous state of self.listmode. So we fix that.
The function's SEF status was not taken into account when substituting functions with their values. This affected llModPow and llXorBase64Strings, both of which have a delay, and were erroneously substituted.
But allow them to be substituted when in calculator mode.
When 'if', 'for', and 'while' statements have a label as the sub-statement, e.g. `while (FALSE) @label;`, the label was improperly removed in some cases, causing a potential compilation failure.
Why someone would want to do that, one never knows, but just to be sure, it has been fixed.
When a global list includes a reference to a global variable of type key, the corresponding list entry type is string, not key (SCR-295, possibly caused by SVC-1710 or SVC-4485).
This implementation is fishy, because it hard-codes the type in the node regardless of the child types. But in some quick experimenting, it seemed to work. And since the main purpose is to document LSO's behaviour, rather than actually being usable, it's OK like that.
The rationale for using -1 was that it had all bits set, but that's a pretty weak argument, really. Lack of optimization of the sign could be worse, so we change it to 1, which is the value of the constant TRUE.
Also change the wording of a comment, for clarity.
The reason is they have an embedded delay. A script might rely on it, therefore substituting the call with its value is not equivalent to leaving the call. They were both already excluded from the SEF table for the same reason.
When we reduced the scope of the try block in commit a823158, we introduced a bug because the tree modification was attempted even if no value was assigned (when the exception was triggered). Returning when the function is not computable ensures that this won't happen.
Scaringly, there was no check that caught this.
Apparently, under Windows, Python does a UTF-16 word-by-word comparison when comparing two strings:
>>> u'\ud700' < u'\U0001d41a'
True
>>> u'\ue000' < u'\U0001d41a'
False
Fix it by encoding as UTF-32 big endian before comparison, when that happens.
- Remove it from lslextrafuncs, and move all the code to lslbasefuncs.
- Make it behave like SL's more accurately. Denormals return 0 always in SL.
- Use int() for truncation rather then floor/ceil.
- Add test cases.
inf and nan already did the right thing in Python, but just in case that doesn't happen in all platforms, we handle them explicitly. Also, that will make it more immune to bugs in future.
We had a big chaos with type conversion. That caused a bug where passing a key to a function that required a string, or vice versa, crashed the script.
Diminish the chaos by modifying the parameters just prior to invocation (in lslfoldconst). We also remove the, now unnecessary, calls to force floats, either alone or within vectors or quaternions.
The previous commit didn't work as expected. "from module import var" freezes the value at load time; changing it later has no effect. A reference to the module needs to be used.
Fix that and the similar problem with LSO. Also revert some "from lslcommon import *" introduced earlier.
That also revealed another bug about missing 'cond' in the import list of lslextrafuncs. This should fix all functions that return values on null key input.
Instead of using an option in the command line, use a global in lslcommon, settable by the main program (only the main LSLCalc program, which differs from LSL-PyOptimizer's main, changes it).
