The root nodes of the dag need to be evaluated in execution order as some
roots may depend on the results of earlier roots (but then, this might also
be related to the problem of function calls not specifying all of their
parameters to the dag).
An instruction that both reads and writes the same variable will read the
variable before writing to it, so the instruction uses the variable rather
than defines it (for live-variable purposes).
First, it turns out using daglabels wasn't such a workable plan (due to
labels being flushed every sblock). Instead, flowvars are used. Each actual
variable (whether normal or temp) has a pointer to the flowvar attached to
that variable.
For each variable, the statements that use or define the variable are
recorded in the appropriate set attached to each (flow)variable.
The flow graph nodes are now properly separated from the graph, and edge
information is stored in the graph struct. This actually made for much
cleaner code (partly thanks to the use of sets and set iterators).
Flow graph reduction has been (temporarily) ripped out as the entire
approach was wrong. There was also a bug in that I didn't really understand
the dragon book about selecting nodes and thus messed things up. The
depth-first search tree "fixed" the problem, but was really the wrong
solution (sledge hammer :P).
Also, now that I understand that dot's directed graphs must be acyclic, I
now have much better control over the graphs (back edges need to be
flipped).
It turns out dot does not like cyclic graphs (thus some of the weird
layouts), but fixing it by flipping back-edges requires proper recording of
edge info (I guess that's what T is for in the dragon book).
The reduction is performed itteratively until the graph is irreducible, but
such that each reduction wraps the previous graph. Unfortunately, due
depth-first searching not being implemented, graphs that should be reduced
(ie, those with natural loops).
set_first() now returns a pointer to a setstate_t struct that holds the
state necessary for scanning a set. set_next() will automatically delete
the state block when the end of the set is reached. set_delstate() is also
provided to allow early termination of the scan.
They're now dot_sblock.c and print_sblock. The new names both better
reflect their purpose and free up "flow" for outputting the real flow
analysis graphs.
Much of the data recently added to sblock_t has been moved to flownode_t.
No graph reduction is carried out yet, but the initial (innermost level)
graph has been built.
Dot interprets escape sequences in non-html string, and needs the quotes to
be escaped, so quote the result of operand_string. Unfortunately,
operand_string uses quote_string and quote_string returns a static pointer,
so some hoop-jumping is necessary.
It seems the dag creation algorithm doesn't like "a = a op a", so use
"b = a op a" instead. Since I plan on fixing temp leaks anyway, this won't
be a problem (also, few people even use qfcc's v6 float modulo :P).
Because of the way it is used, the data in the type encodings space needs
to always be correct (ie, relocated), even for partially linked object
files.
Rather, only that it is neither external nor local. The idea was to catch
myself swapping the arguments to resolve_external_def, but for some reason
I decided type encoding defs would not be global (save game reasons?).
Fixes the bogus redefined errors when entity fields are used.
Also, rename extern_defs and defined_defs to extern_data_defs and
defined_data_defs (more consistent with the other tables).
The problem was caused by add_relocs and process_loose_relocs adjusting the
reloc offset based on the reloc's space's base address. This is fine for
most relocs, but as relocs for the type space have already been adjusted by
process_type_space, those relocs must be left alone by add_relocs and
process_loose_relocs. As a bonus, the duplicate code has been refactored
into a separate function :)
Now each encoding is copied across def by def using memcpy, with the
expectation that any references to other types will be handled via the
reloc system. Unfortunately, it seems there's an off-by-4 (hmm, suspicious
number...) in the reloc offsets, but I'll look into that after I get some
sleep.
defspace_alloc_loc can cause a realloc which will break the work qfo space
data pointers, so wrap it with alloc_data, which updates the appropriate
pointers and sizes.
The field/data def handling has been moved into process_data_def and
process_field def. The code for handling external defs has been moved into
its own function (extern_def()),
In passing, rename add_space to add_data_space, since it is limited to
handling data spaces.
For now, no other change has been made, but I'll be able to split up
process_def for data def vs field def processing and add a function for
processing type encoding defs.
First, the class def needed to be created before the class type, then the
def space indices had to be set early, otherwise the relocs wound up with
space 0 instead of the correct space.
