MOVEP's opc itself is always known and used, whether it's a constant
pointer or variable doesn't matter. This fixes the lost pointer calculation
for va_list.list[j] = object_from_plist (item);
Dead nodes are those that generate unused values (unassigned leaf nodes,
expressions or destinationless move(p) nodes). The revoval is done by the
flow analysis code (via the dags code) so that any pre and post removal
flow analysis and manipulation may be done (eg, available expressions).
assign_expr mangles the destination expression for dereferenced
assignments into something that is invalid as an lvalue, so simply use
new_binary_expr with the same opcode.
It turns out expression trees are (mostly?) valid DAGs, so all edges being
constrained works, though the graphs get a little tall (but easier to read).
This fixes the infinite loop in if ((x = self.heat && x))
Really, I think I need to revisit the whole expression tree code. It's
proving to be rather fragile.
The source of the assignment is used as the value to test, and the
assignment itself is inserted into the boolean expressions's block. This
fixes the inernal error for "if ((x = 0))".
Normally, it will happen only as a follow-on error, but I can think of a
way to force it without other errors, so treating it as an internal error
is a bit harsh.
But reset current_symtab to its prior value when done. This fixes a
segfault caused by initializing the class system while parsing a struct
(eg, one of the members is of type id).
The keywords table was rather awkward to edit (and sometimes confusing).
Worse, because the hash table used to look up the keywords was initialized
only once, changing modes in the same execution of qfcc would not work
properly as keywords would not be added or removed as appropriate.
Now there are four categories of keywords:
o "core" Always available. They form the core of QuakeC except for two
extensions.
o "@" In extended and advanced modes, the preceeding @ is optional,
but tranditional mode requires the keywords to be preceeded by
an @. They are the C keywords that QuakeC did not use, but can
be implemented in v6 progs under certain circumstances.
o "QF" These keywords require the QuakeForge VM to be usable.
o "Obj" These keywords form Ruamoko/Objective-QuakeC and require both
advanced mode and the QuakeForge VM.
This fixes the segfault/null pointer access in sendv.r. While I wanted to
use the edge setting code to set the live bit, I didn't expect it to be
this easy. def_visit_all is proving to be worth every bit it consumes :)
It seems dag_set_live_vars still served a purpose after all, but I don't
feel like bringing it as I'd rather implement its param handing in
dagnode_set_edges. I've now got a test case for it, though the test
currently causes the VM to segfault (even with pr_boundscheck 2!).
If the final block ends in a conditional statement, appending return to the
block will hide the conditional statement from the flow analyzer. This may
cause the conditional statement's destination node be become unreachable
according to the analyzer and thus eliminated. The label for the branch
then loses its target sblock and thus the code generator will produce a
zero-distance jump resulting in an infinite loop.
Thus, if the final block ends in a conditional statement (or, for
completeness, a call statement), append a new empty block before adding the
return statement.
If MOVEP's destination is variable, then the actual destination isn't (at
this stage) knowable, so it can't be attached to the dagnode and thus must
be a child.
Getting the operands directly from the statement was missing the
destination operand of movep when movep's op_c was a constant pointer and
thus the flowvar wasn't being counted/created early enough. This led to a
segfault in the set code when attempting to add -1 to the set.
It turns out the recent dead-block code "broke" vector component access
from objects. The breakage is really highlighting a problem with temporary
operands and aliasing. The problem was hiding behind a basic-block split
that the recent dead-block work mended and thus exposed the bug.
type_id is implemented as a pointer to "struct obj_object" (ie, not really
a class), so the correct check is to ensure the type is:
1 a pointer
2 to a struct
3 using the same symbol table as type_obj_object
Empty structs are now (correctly) invalid. The hack of using an empty
struct to represent a handle returned from a builtin has been unnecessary
since opaque structs were implemented: now a pointer to an opaque struct
can be used. This is mostly safe as handles are aways negative and thus
attempting to dereference such a pointer should result in a VM error. It
will be even safer once const is implemented and the pointers can be made
constant (eg, typedef struct handle * const handle;)
void foo (int); is fine for a prototype (or, presumably, a qc function
variable), but not for an actual function body. This fixes the segmentation
fault when the parameter name is omitted.
This is needed to allow compile-time protocol conformance checks, though
nothing along those lines has been implemented yet.
id has been changed from TYPE to OBJECT, required to allow id <proto> to be
parsed. OBJECT uses symbol, allowing id to be redefined once suitable work
has been done on the parser.
It uses the new block merge code. Now forgotten return statements are
detected properly (naive dead block removal) and all unreachable code is
eliminated (flow analysis unreachable node removal).
This reverts commit 83ead0842f.
Note: does not compile.
It turns out basic dead block removal is needed for the "control reaches
end of non-void function" warning to work correctly.
Empty sblocks are removed (unless it's the only sblock), and blocks that
are split unnecessarily are merged.
This mostly fixes bogus "no return" warnings.
Unreachable nodes will cause the first elements of the array to remain
unwritten by df_search. This fixes the segfaults caused by unreachable
nodes (the reason they were an internal error before).
The current implementation probably needs more work, but for the case where
I needed it, it does the job.
grid.r💯 vector size = {range, range, 0};
0115 store.f range, size
0116 store.f range, [$2ac]
0117 store.f .zero, [$2ad]
After all that effort getting the class def initialized early enough for
type encodings to work, it proved to be a problem: just including a header
with an interface in it would cause linker errors if there was no
implementation available (even if the class is never used).
qfcc now does local common subexpression elimination. It seems to work, but
is optional (default off): use -O to enable. Also, uninitialized variable
detection is finally back :)
The progs engine now has very basic valgrind-like functionality for
checking pointer accesses. Enable with pr_boundscheck 2
Temps aren't supported yet :P
The alias defs themselves aren't killed (still want any assignments to
occur) but rather, their nodes are. Also, edges to the alias defs' nodes
are added to the assigning node. Fixes structlive.r :)
I got fed up with using "int" types, but the members being "integer"
(hold-over from before the int rename).
Also, correct the names of those types and @va_list (error reporting was
chopping off part of the name).
MOVE (static move) and MOVEP to a pointer constant know exactly where their
data is going, so treat them similarly to assignments: save their
distination operands (the addressed def for MOVEP) and mark them as
defined.
The live var flow analysis doesn't check for aliases. Rather than changing
it to check for aliases (which might break uninitialized var analysis, as
it uses "use" from the live var analysis), make dag_remove_dead_vars do the
check. Fixes the misplaced text in the menus.
Nifty: if you pass a struct via reference to a function, and a field of
that struct may be both set and not set (eg, set only in an if statement),
gcc will report that field assuming that fields that are never set will be
set by the function (my interpretation).
* taniwha ponders the flow analysis for that
Nifty: if you pass a struct via reference to a function, and a field of
that struct may be both set and not set (eg, set only in an if statement),
gcc will report that field assuming that fields that are never set will be
set by the function (my interpretation).
* taniwha ponders the flow analysis for that
At the statement level, all pointer types are the same, so just return the
op obtained from the sub-expression when the low-level type of the alias
expression matches the low-level type of the type of type sub-expression
operand.
With this, the alias of a value code can be removed (I always thought it
was wrong), which is what broke calling obj_msgSend_super (type &.super
param lost the &).
Now I have to deal with pointer values in the optimizer :/
When an alais def (or aliased def) is used, any overlapping aliases that
have previously been assigned need to be marked as live, and edges to the
aliases added to the new node. However, when assigned to, live-forcing
needs to be turned off.
This fixes the lost assignments to .super.
This fixes the bogus temps for "*to = *from++;", but qfcc ices due to the
operand types being lost. It seems alias operands need to be resurrected,
if only for code output by dags.
I forgot to add func->num_statements :P. Fixes the weirdness where only
some alias temps were being (bogusly) detected as uninitialized. Now they
all are.
When the naive uninitialized variable detection finds a node with possible
uses of uninitialized variables, the statements in the node are scanned one
at a time checking each usage and removing uninitialized definitions as
appropriate. vectest.r now compiles without warnings. As an added bonus,
accurate line number information is reported for uninitialized variables.
Unfortunately, there is still a problem with uninitialized temps in
switch.r, but that might just be poor handling of temp op aliases.
Only definitions for the def used in the current statement (whether an
alias or not) are suitable for killing. Doing otherwise defeats the purpose
of this work :P
Fixes the false negatives found in a modified quattest.r (commented out the
"tq.s = 0;" line).
Nicely, the use sets from live_variable analysis can be used too, though
there are some problems with the naive implementation. For:
vector foo (float x, float y, float z)
{
vector v;
v.x = x;
v.y = y;
v.z = z;
return v;
}
qfcc thinks v is uninitialized, but if "if (x) return nil;" (or any other
basic-block splitter) is put just before the return v; qfcc correctly
detects that v is initialized. The reason is that the inits are in the same
basic block as the return, and thus aren't affecting the reaching
definitions, which are stored per-block.
The naive implementation should be good for a fast-cull before doing a
per-statement check.
The exit dummy block is setup to provide dummy uses of global variables to
the live variable analysis doesn't miss global variables. Much cleaner than
the previous code :) There may be some issues with aliases, though.
The entry dummy block is setup to provide dummy definitions of local
variables so the reaching definitions analysis can be used to detect
uninitialized variables (not implemented yet). Fake statement numbers
(func->num_statements + X) are used to represent the definitions. Local
variables (ie, not temp ops) use their offsets (ie, the offset range they
cover) for X. Temp ops use their flowvar number + the size of the
function's defspace for X. flow_kill_aliases() should take care of temp op
aliasing, while the use of the actual offsets spanned by the variable's def
should take care of any wild aliasing so structures and unions should
become a non-issue.
The dummy nodes are for detectining uninitialized variables (entry dummy)
and making globals live at function exit (exit dummy). The reaching defs
and live vars code currently seg because neither node has had its sets
initialized.
Fixed aliases are those that will never change through the life of the
code. They are generated from structure accesses and thus what they alias
is always known.
Also move the ALLOC/FREE macros from qfcc.h to QF/alloc.h (needed to for
set.c).
Both modules are more generally useful than just for qfcc (eg, set
builtins for ruamoko).
Set of everything is implemented by inverting the meaning of bits in the
bitmap: 1 becomes non-member, 0 member. This means that set_size and
set_first/set_next become inverted and represent non-members as counting
members becomes impossible :)
Aliasing the jump table to an integer broke statement_get_targetlist with
the new alias def handling, and was really wrong anyway. I probably did
that due to being fed up with things and wanting to get qfcc working again
rather than spending time getting jumpb right.
With the need to handle aliasing in the optimizer, it has become apparent
that having the flow data attached to symbols is not nearly as useful as
having it attached to defs (which are views of the actual variables).
This also involves a bit of a cleanup of operand types: op_pointer and
op_alias are gone (this seems to greatly simplify the optimizer)
There is a bit of a problem with enums in switch statements, but this might
actually be a sign that something is not quite right in the switch code
(other than enums not being recognized as ints for jump table
optimization).
Turns out there was only one place to fix (for qc, anyway: I don't have
tests for qp yet). func-static now passes :)
Hmm, how to test for static var naming... (not implemented yet)
Simply "backed" and "virutal". Backed spaces have memory allocated to them
while virtual spaces do not. Virtual spaces are intended for local
variables and entity fields.
It turns out they're not getting allocated properly (they're put in the
function's locals defspace rather than near data), but fixing it proved a
little more problematic than expected, so the test is marked as XFAIL for
now to remind me to fix it.
With this, alias defs become singletons based on the def they alias and the
type and offset of the alias. Thus, the removal of the free_def call in
emit.c.
alias_def now always creates an offset def (though the usual case has an
offset of 0). The if the alias escapes the bounds of the base def, an
internal error will be generated.
It really doesn't seem wise to allow the compiler to do so as it would
overwrite unrelated defs. The only time such a thing is valid is the return
statement (silly vm design), and that's read-only.
Also remove the extern for current_storage as it belongs in shared.h.
I'm not satisfied with the documentation for initialize_def, but it will do
for now. I probably have to rewrite the thing as it's a bit of a beast.
With the intoduction of the statement type enum came a prefix clash. As
"st" makes sense for "statement type", I decided that "storage class"
should be "sc". Although there haven't been any problems as of yet, I
decided it would be a good idea to clean up the clash now. It also helps
avoid confusion (I was a bit surprised after working with st_assign etc to
be reminded of st_extern etc).
qfcc isn't meant to be long running, so I'm not super worried about memory
usage, but definitely lost memory blocks when compiling just a single
function seems a tad sloppy.
It doesn't quite work yet, but...
It has proven necessary to know what type .return has at any point in the
function. The segfault in ctf is caused by the return statement added to
the end of the void function messing with the expr pointer stored in the
daglabel for .return. While this is actually by design (though the
statement really should have a valid expr pointer rather than), it actually
highlights a bigger problem: there's no stable knowledge of the current
type of .return. This is not a problem in expression statements as the
dagnodes for expression statements store the desired types of all operands.
However, when assigning from .return to attached variables in a leaf node,
the type of .return is not stored anywhere but the expression last
accessing .return.
Bill Currie