While there was a breakpoint hook, it was for only breakpoints and more
was needed. Now there's a generic hook that is called for tracing,
breakpoints, watch points, runtime errors and VM errors, with the
"event" type passed as the first parameter and a data pointer in the
second.
The idea is to find th def that contains the address. Had to write my
own bsearch (well... lifted from wikipedia) because libc's is exact. The
defs are assumed to be sorted (which qfcc now ensures when it writes
progs and sym files).
This "pushes" a temp string onto the callee's stack frame after removing
it from the caller's stack frame. This is so builtins can pass
auto-freed memory to called progs code. No checking is done, but mayhem
is likely to ensue if a string is pushed that was allocated in an
earlier frame.
PR_AllocTempBlock() works the same way as PR_SetTempString(), except
that it takes a size parameter and always allocates (never tries to
merge). This is, in a way, abusing the string system, but I needed a way
to allocate a block of progs memory that would be automatically freed
when the current frame ended. The biggest abuse is the need to cast away
the const of PR_GetString()'s return value.
The progs execution code will call a breakpoint handler just before
executing an instruction with the flag set. This means there's no need
for the breakpoint handler to mess with execution state or even the
instruction in order to continue past the breakpoint.
The flag being set in a progs file is invalid.
The debug subsystem now uses the resources system to ensure it cleans
up, and its data is now semi-private. Unfortunately, PR_LoadDebug had to
remain public for qfprogs because using PR_RunLoadFuncs would cause
builtin resolution to complain.
It is now set to 0 when progs are loaded and every time
PR_ExecuteProgram() returns. This takes care of the default case, but
when setting parameters, pr_argc needs to be set correctly in case a
vararg function is called.
PR_SaveParams() is required for implementing the +initialize diversion
used by Objective-QuakeC because builtins do not have local def spaces
(of course, a normal stack calling convention would help). However, it
is entirely possible for a call to +initialize to trigger another call
to +initialize, thus the need for stacking parameter stashes. As a
bonus, this implementation cleans up some fields in progs_t.
The engine now requires non-v6 progs to store the log2 alignment for the
param struct in .param_alignment.
PR_EnterFunction is clearer and possibly more efficient.
Only as scalars, I still need to think about what to do for vectors and
quaternions due to param size issues. Also, doubles are not yet
guaranteed to be correctly aligned.
I've decided that setting pr.max_edicts and pr.zone_size as part of the
local progs initialization rather than in PR_LoadProgsFile makes more
sense. For one, it is unlikely for the limits to change every time progs is
reloaded. Also, they seem to be a property of the VM rather than the progs.
However, there is nothing stopping the caller from updating max_edicts and
zone_size every call.
I'd forgotten that ED_ConvertToPlist mangled light into light_lev and
single component angle values into a vector. This fixes much of the
breakage in qflight (but not the light levels)
