The ud- and du-chains include known side-effects of the instructions and
thus depict a more accurate view of what operands an instruction uses or
defines. Fixes the arraylife2 test.
Like defs, a partial write should not define the whole temp. Thus, copy
the "don't visit main" behavior recently added to def_visit_all. Fixes
missing ud-chains for component-by-component assignments to temporary
vectors.
I'm not certain this is correct, but it seems to me that du-chains are
the same information as ud-chains, but from the defining statement's
point of view instead of that of the using statement.
As certain statements (in particular, function calls) can use additional
variables via pointer parameters, it's necessary to iterate ud-chain
building until the count stabilizes. This should make live variable
analysis much easier.
I think the current build_element_chain implementation does a reasonable
job, but I'm in the process of getting designated initializers working,
thus it will become important to ensure uninitialized members get
initialized.
I never liked the various hacks I had come up with for representing
resource handles in Ruamoko. Structs with an int were awkward to test,
pointers and ints could be modified, etc etc. The new @handle keyword (@
used to keep handle free for use) works just like struct, union and
enum in syntax, but creates an opaque type suitable for a 32-bit handle.
The backing type is a function so v6 progs can use it without (all the
necessary opcodes exist) and no modifications were needed for
type-checking in binary expressions, but only assignment and comparisons
are supported, and (of course) nil. Tested using cbuf_t and QFile: seems
to work as desired.
I had considered 64-bit handles, but really, if more than 4G resource
objects are needed, I'm not sure QF can handle the game. However, that
limit is per resource manager, not total.
This takes advantage of the ud-chains to follow the trail of pointer
assignments looking for an address. This gets array element assignments
surviving across blocks when the array itself is passed to a function.
It doesn't help when the address of the element is taken though. I think
that's a dags problem and probably needs du-chains. Also, the ud-chain
creation should probably be done in two passes so the newly found
information can be recorded.
Def and kill are still handled in flow_analyze_statement, but this makes
call meta data more consistent between v6 and ruamoko progs, allowing
the statement use chain to be used for call argument analysis. It even
found a bug in the extraction of param counts from the call instruction.
I had missed the flowvar clearing for auxiliary use/def/kill operands.
It's possible it wasn't necessary at the time since the operands were
added just for dealloc checking, but there's every reason it could
become necessary.
The first use will be pointer analysis for function arguments where the
argument points to an array to mark the array as live, but I'm sure
there'll be plenty of other uses.
A partial write to a def should not define the whole def, thus
def_visit_all's overlap parameter now has a flag that prevents a visit
to the main def when accessing the def from an alias def. This prevents
a lot of spurious kills and defines in flow analysis.
The array access code was loading the vector, modifying the element,
then forgetting to write the modified vector back to whence it came.
However, that would be rather sub-optimal, so now when the vector is
accessed by a pointer, the array code switches to field access to get at
the vector element thus avoiding the need to copy the whole vector.
Needed for proper analysis (ud-chains etc). Of course, it was then
necessary to remove the parameter defs from the uninitialized defs.
Also, plug a couple of memory leaks (forgot to free some temporary
sets).
That is, `array + offset`. This actually works around the bug
highlighted by arraylife.r (because the array is explicitly used), but
is not a proper solution, so that test still fails of course. However,
with this, it's no longer necessary to use `&array[index]` instead of
`array + index`.
I could never remember what any of the numbers meant. While define is
still a little fuzzy (they're (pseudo)statement numbers), at least now
I'll always know that the numbers are the define set. Also, having the
flow address of the variable helps with understanding the reaching defs
output.
I had messed up the handling of declarators for combinations of pointer,
function, and array: the pointer would get lost (and presumably arrays
of functions etc). I think I had gotten confused and thought things were
a tree rather than a simple list, but Holub set me straight once again
(I've never regretted getting that book). Once I understood that, it was
just a matter of finding all the places that needed to be fixed. Nicely,
most of the duplicated code has been refactored and should be easier to
debug in the future.
The type system rewrite had lost some of the checks for function fields.
This puts the actual code in the one place and covers parameters as well
as globals.
Internally, * is not really a valid operator for vectors since it can
have many meanings. This didn't cause trouble until trying to build
everything in game-source (since there's still a lot of legacy code in
there).
The precedence check changes done in
63795e790b seem to have been incorrect
(game-source/ctf produced many false positives), so putting that check
against '=' back into the code seems like a good idea (no more false
positives). That sounds a bit cargo-cult, but I'm really not sure what I
was thinking when I did the changes (probably just tired).
This applies only to the top-level scope of the function. I'm not sure
if it's right for traditional quakec code, but that can be adjusted
easily enough.
The symtab code itself cares only about global/not global for the size
of the hash table, but other code can use the symtab type for various
checks (eg, parameter shadowing).
Along with QuakeC's, of course. This fixes type typeredef2 test (a lot
of work for one little syntax error). Unfortunately, it came at the cost
of requiring `>>` in front of state expressions on C-style functions
(QuakeC-style functions are unaffected). Also, there are now two
shift/reduce conflicts with structs and unions (but these same conflicts
are in gcc 3.4).
This has highlighted the need for having the equivalent of the
expression tree for the declaration system as there are now several
hacks to deal with the separation of types and declarators. But that's a
job for another week.
The grammar constructs for declarations come from gcc 3.4's parser (I
think it's the last version of gcc that used bison. Also, 3.4 is still
GPL 2, so no chance of an issue there).
This simplifies type type_specifier rule significantly as now TYPE_SPEC
(was TYPE) includes all types and their basic modifiers (long, short,
signed, unsigned). This should allow me to make the type system closer
to gcc's (as of 3.4 as that seems to be the last version that used a
bison parser) and thus fix typeredef2.
Once a unicode char (ie, > 127) was used, any ascii chars would get the
tail of the last unicode char resulting in broken utf-8 streams. The
resulting null glyph boxes were not very appealing.
This fixes the basic vecconst test (extending it to other types breaks
because long and ulong are not properly supported yet). The conversion
is done by the progs VM rather than writing another 256 conversions
(though loops could be used). This works nicely as a test for using the
VM to help with compiling.
While the option to make '*' mean dot product for vectors is important,
it breaks vector scaling in ruamoko progs as the resultant vector op
becomes a dot product instead of the indented hadamard product (ie,
component-wise).
