- fixed code generation for using local variables as array index. This must use a different register for the array element offset because the original register may not be overwritten.
This could cause problems with functions that take states as parameters but use them to set them internally instead of passing them through the A_Jump interface back to the caller, like A_Chase or A_LookEx.
This required some quite significant refactoring because the entire state resolution logic had been baked into the compiler which turned out to be a major maintenance problem.
Fixed this by adding a new builtin type 'statelabel'. This is an opaque identifier representing a state, with the actual data either directly encoded into the number for single label state or an index into a state information table.
The state resolution is now the task of the called function as it should always have remained. Note, that this required giving back the 'action' qualifier to most state jumping functions.
- refactored most A_Jump checkers to a two stage setup with a pure checker that returns a boolean and a scripted A_Jump wrapper, for some simpler checks the checker function was entirely omitted and calculated inline in the A_Jump function. It is strongly recommended to use the boolean checkers unless using an inline function invocation in a state as they lead to vastly clearer code and offer more flexibility.
- let Min() and Max() use the OP_MIN and OP_MAX opcodes. Although these were present, these function were implemented using some grossly inefficient branching tests.
- the DECORATE 'state' cast kludge will now actually call ResolveState because a state label is not a state and needs conversion.
- Since the number of small allocations here is extremely high this will help a lot to prevent fragmentation and since most nodes are collected up front and this is done when no large resources are being loaded it won't cause heap spikes.
let Emit methods delete FxExpression arrays when they are done.
- For some reason the deletion process does not work 100%, there are always some nodes left behind and so far I haven't found them. This ensures that these arrays do not live any longer than needed.
* use the function build list instead of the function to pass the info. The function is permanent so not the best place for compile-time info.
* pass along the current state index which is needed to calculate the target state.
- added support for global variables to the code generator - not the compiler, though. For the handful of entries this is needed for it may just as well be done manually. So far FLevelLocals level is the only one being exported.
- fixed: The VM disassembler truncated 64 bit pointers to 15 digits because the output buffer was too small.
- resolve entire FxSequences instead of aborting on the first failed entry. This allows to output all errors at once.
- exported thinker iterator and drop item chain to scripting. Unlike its native counterpart the script-side iterator is wrapped into a DObject to allow proper handling for memory management.
- fixed: The VMFunctionBuilder only distinguished between member and action functions but failed on static ones.
- fixed: FxAssign did not add all needed type casts. Except for purely numeric types it will now wrap the expression in an FxTypeCast. Numeric handling remains unchanged for both performance reasons and not altering semantics for DECORATE.
- exported all internal flags as variables to scripting. They still cannot be used in an actor definition.
- make ATAG_STATE the same as ATAG_GENERIC. Since state pointers exist as actual variables they can take both values which on occasion can trigger some asserts.
- gave PClass a bExported flag, so that scripts cannot see purely internal classes. Especially the types like PInt can cause problems.
Todo: we need readonly references to safely expose the actor defaults. Right now some badly behaving code could overwrite them.
- removed mulv_kr and divv_kr instructions. The first are redundant and the second are useless. Maybe remove all other vector/const operations as well? They won't get used by the code generator.
- fixed disassembly of vector multiplication and division instructions.
- fixed: ZCCCompiler did not process array access nodes.
- fixed: Function argument names were not placed in the destination list by the compiler.
- scriptified several trivial functions from p_actionfunctions.cpp.
- disabled the assert in PType::GetRegType. This assert blocks any use to check for types that are incompatible with function parameters.
- pass the default parameter constants to the native functions. At the moment this is not used yet.
- use the function defaults to complete argument lists to script functions.
- fixed all default values that got flagged by the expression evaluator as non-constant. Most were state labels and colors which were defaulted to "". The proper value is null for states and 0 for colors.
- also replaced all "" defaults for names with "none".
- fixed: Script functions did not receive the function name when being created.
- relaxed the asserts for PARAM_STATE, because the VM knows nothing about ATAG_STATE. Any state variable's content (e.g. Actor.SeeState) will receive ATAG_GENERIC, rather than ATAG_STATE.
- added a 'NeedResult' flag so that certain operations can create shorter code if the result of the expression is not needed. So far only used for postdecrement/increment statements on local variables (which is the most frequent case where this matters.)
- fixed postincrement and decrement for local variables. Due to the result preservation semantics it created faulty code.
- synthesize PField entries from the flag list for AActor. This intentionally excludes the bounce flags for now.
- allow deprecated flags that do not call the deprecated flag handler.
- disallow constructs like (a = b) = c by not allowing an address request on an assignment operation.
- restrict modify/assign on boolean variables to the bit operators. Everything else needs to promote the result to an integer to make sense so it should be disallowed.
- added the above for the 'if' condition. It works for integers, floats and pointers and will save 3 instructions if the condition is a non-boolean that can be implicitly casted to bool.
- added a TESTN instruction. This is like TEST but negates the operand. This was added to avoid flooding the constant table with too many case labels. With TEST and TESTN combined, all numbers between -65535 and 65535 can be kept entirely inside the instruction. Numbers outside this range still use a BEQ instruction.
This is not testable right now because finally the action function mess has come full circle. The current setup makes it impossible to call action functions from non-action functions because the needed info is local to the functions.
Long avoided, this needs to be refactored now so that the different semantics for action functions are no longer needed.
- fixed: FxMemberIdentifier checked for ClassPointers instead of object pointers to resolve the left hand side of the expression.
- allow comparison of pointers.
The generated object code can definitely use an optimization pass but that's something left for later when more things are working. Right now it creates one opcode more than necessary for all member accesses (instead of using the offset in the store command it calculates an actual address of the variable in another address register) and can create one too many for non-constant expressions being assigned to local variables (a move between two registers because the emitted expression on the right hand side does not know that it can emit to the actual variable's register.)
- create proper variable data from the function prototype instead of assuming that there's just 3 pointers.
- added a printable name to VMScriptFunction for error output during gameplay in case something goes wrong.
All break and continue statements were collected in one list, and each loop statement taking hold of that entire list, including the breaks and continues from previous outer loops.
Changed it so that loop statements contain the jump addresses themselves and set a pointer in FCompileContext, so that the jump point can be set directly in the loop statement - and an error printed if there is none in the resolving stage, not the emitting one.
Consolidated the identical backpatching code of the three loop statement nodes into a subfunction.
- handle all binary operators which are already implemented in the code generator.
- implemented sizeof/alignof operators in code generator.
- rewrote RequestAddress so that its return value is not the writability of an address but the mere existence. Also changed it to not output errors itself because those cannot be dealt with by the calling function.
- fixed: FxBinary::ResolveLR' check for numeric operations was incomplete. Like far too many other places it just assumed that everything with ValueType->GetRegType() == REGT_INT is a numeric type, but for names this is not the case.
- added a descriptive name to all types for error messages.
- added a generic type cast node to the code generator.
- added a few more cast operations to the 'cast' VM instruction.
- extended FxClassTypeCast to handle all possible input that can be cast to a class pointer, not just names.
