4.4BSD/usr/src/old/dbx/runtime.vax.c
/*
* Copyright (c) 1983 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char sccsid[] = "@(#)runtime.vax.c 5.6 (Berkeley) 1/27/91";
#endif /* not lint */
/*
* Runtime organization dependent routines, mostly dealing with
* activation records.
*/
#include "defs.h"
#include "runtime.h"
#include "process.h"
#include "machine.h"
#include "events.h"
#include "mappings.h"
#include "symbols.h"
#include "tree.h"
#include "eval.h"
#include "operators.h"
#include "object.h"
#include <sys/param.h>
#include <signal.h>
#ifndef public
typedef struct Frame *Frame;
#include "machine.h"
#endif
#define NSAVEREG 12
struct Frame {
integer condition_handler;
integer mask;
Address save_ap; /* argument pointer */
Address save_fp; /* frame pointer */
Address save_pc; /* program counter */
Word save_reg[NSAVEREG]; /* not necessarily there */
};
private Frame curframe = nil;
private struct Frame curframerec;
private Boolean walkingstack = false;
#define frameeq(f1, f2) ((f1)->save_fp == (f2)->save_fp)
#define inSignalHandler(addr) \
(((addr) < 0x80000000) and ((addr) > 0x80000000 - ctob(UPAGES)))
typedef struct {
Node callnode;
Node cmdnode;
boolean isfunc;
} CallEnv;
private CallEnv endproc;
/*
* Set a frame to the current activation record.
*/
private getcurframe(frp)
Frame frp;
{
register int i;
checkref(frp);
frp->mask = reg(NREG);
frp->save_ap = reg(ARGP);
frp->save_fp = reg(FRP);
frp->save_pc = reg(PROGCTR);
for (i = 0; i < NSAVEREG; i++) {
frp->save_reg[i] = reg(i);
}
}
/*
* Get the saved registers from one frame to another
* given mask specifying which registers were actually saved.
*/
#define bis(b, n) ((b & (1 << (n))) != 0)
private getsaveregs (newfrp, frp, mask)
Frame newfrp, frp;
integer mask;
{
integer i, j;
j = 0;
for (i = 0; i < NSAVEREG; i++) {
if (bis(mask, i)) {
newfrp->save_reg[i] = frp->save_reg[j];
++j;
}
}
}
/*
* Return a pointer to the next activation record up the stack.
* Return nil if there is none.
* Writes over space pointed to by given argument.
*/
private Frame nextframe(frp)
Frame frp;
{
Frame newfrp;
struct Frame frame;
integer mask;
Address prev_frame, callpc;
static integer ntramp = 0;
newfrp = frp;
prev_frame = frp->save_fp;
/*
* The check for interrupt generated frames is taken from adb with only
* partial understanding. If you're in "sub" and on a sigxxx "sigsub"
* gets control, then the stack does NOT look like <main, sub, sigsub>.
*
* As best I can make out it looks like:
*
* <main, (machine check exception block + sub), sysframe, sigsub>.
*
* When the signal occurs an exception block and a frame for the routine
* in which it occured are pushed on the user stack. Then another frame
* is pushed corresponding to a call from the kernel to sigsub.
*
* The addr in sub at which the exception occured is not in sub.save_pc
* but in the machine check exception block. It is at the magic address
* fp + 84.
*
* The current approach ignores the sys_frame (what adb reports as sigtramp)
* and takes the pc for sub from the exception block. This allows the
* "where" command to report <main, sub, sigsub>, which seems reasonable.
*/
nextf:
if (prev_frame + sizeof(struct Frame) <= USRSTACK) {
dread(&frame, prev_frame, sizeof(struct Frame));
} else if (USRSTACK - prev_frame > 2 * sizeof(Word)) {
dread(&frame, prev_frame, USRSTACK - prev_frame);
} else {
frame.save_fp = nil;
}
if (ntramp == 1) {
dread(&callpc, prev_frame + 92, sizeof(callpc));
} else {
callpc = frame.save_pc;
}
if (frame.save_fp == nil or frame.save_pc == (Address) -1) {
newfrp = nil;
} else {
if (inSignalHandler(callpc)) {
ntramp++;
prev_frame = frame.save_fp;
goto nextf;
}
frame.save_pc = callpc;
ntramp = 0;
newfrp->save_fp = frame.save_fp;
newfrp->save_pc = frame.save_pc;
mask = ((frame.mask >> 16) & 0x0fff);
getsaveregs(newfrp, &frame, mask);
newfrp->condition_handler = frame.condition_handler;
newfrp->mask = mask;
newfrp->save_ap = frame.save_ap;
}
return newfrp;
}
/*
* Get the current frame information in the given Frame and store the
* associated function in the given value-result parameter.
*/
private getcurfunc (frp, fp)
Frame frp;
Symbol *fp;
{
getcurframe(frp);
*fp = whatblock(frp->save_pc);
}
/*
* Return the frame associated with the next function up the call stack, or
* nil if there is none. The function is returned in a value-result parameter.
* For "inline" functions the statically outer function and same frame
* are returned.
*/
public Frame nextfunc (frp, fp)
Frame frp;
Symbol *fp;
{
Symbol t;
Frame nfrp;
t = *fp;
checkref(t);
if (isinline(t)) {
t = container(t);
nfrp = frp;
} else {
nfrp = nextframe(frp);
if (nfrp == nil) {
t = nil;
} else {
t = whatblock(nfrp->save_pc);
}
}
*fp = t;
return nfrp;
}
/*
* Return the frame associated with the given function.
* If the function is nil, return the most recently activated frame.
*
* Static allocation for the frame.
*/
public Frame findframe(f)
Symbol f;
{
Frame frp;
static struct Frame frame;
Symbol p;
Boolean done;
frp = &frame;
getcurframe(frp);
if (f != nil) {
if (f == curfunc and curframe != nil) {
*frp = *curframe;
} else {
done = false;
p = whatblock(frp->save_pc);
do {
if (p == f) {
done = true;
} else if (p == program) {
done = true;
frp = nil;
} else {
frp = nextfunc(frp, &p);
if (frp == nil) {
done = true;
}
}
} while (not done);
}
}
return frp;
}
/*
* Set the registers according to the given frame pointer.
*/
public getnewregs (addr)
Address addr;
{
struct Frame frame;
integer i, j, mask;
dread(&frame, addr, sizeof(frame));
setreg(FRP, frame.save_fp);
setreg(PROGCTR, frame.save_pc);
setreg(ARGP, frame.save_ap);
mask = ((frame.mask >> 16) & 0x0fff);
j = 0;
for (i = 0; i < NSAVEREG; i++) {
if (bis(mask, i)) {
setreg(i, frame.save_reg[j]);
++j;
}
}
pc = frame.save_pc;
setcurfunc(whatblock(pc));
}
/*
* Find the return address of the current procedure/function.
*/
public Address return_addr()
{
Frame frp;
Address addr;
struct Frame frame;
frp = &frame;
getcurframe(frp);
frp = nextframe(frp);
if (frp == nil) {
addr = 0;
} else {
addr = frp->save_pc;
}
return addr;
}
/*
* Push the value associated with the current function.
*/
public pushretval(len, isindirect)
integer len;
boolean isindirect;
{
Word r0;
r0 = reg(0);
if (isindirect) {
rpush((Address) r0, len);
} else {
switch (len) {
case sizeof(char):
push(char, r0);
break;
case sizeof(short):
push(short, r0);
break;
default:
if (len == sizeof(Word)) {
push(Word, r0);
} else if (len == 2*sizeof(Word)) {
push(Word, r0);
push(Word, reg(1));
} else {
error("[internal error: bad size %d in pushretval]", len);
}
break;
}
}
}
/*
* Return the base address for locals in the given frame.
*/
public Address locals_base(frp)
Frame frp;
{
return (frp == nil) ? reg(FRP) : frp->save_fp;
}
/*
* Return the base address for arguments in the given frame.
*/
public Address args_base(frp)
Frame frp;
{
return (frp == nil) ? reg(ARGP) : frp->save_ap;
}
/*
* Return saved register n from the given frame.
*/
public Word savereg(n, frp)
integer n;
Frame frp;
{
Word w;
if (frp == nil) {
w = reg(n);
} else {
switch (n) {
case ARGP:
w = frp->save_ap;
break;
case FRP:
w = frp->save_fp;
break;
case STKP:
w = reg(STKP);
break;
case PROGCTR:
w = frp->save_pc;
break;
default:
assert(n >= 0 and n < NSAVEREG);
w = frp->save_reg[n];
break;
}
}
return w;
}
/*
* Return the nth argument to the current procedure.
*/
public Word argn(n, frp)
integer n;
Frame frp;
{
Address argaddr;
Word w;
argaddr = args_base(frp) + (n * sizeof(Word));
dread(&w, argaddr, sizeof(w));
return w;
}
/*
* Print a list of currently active blocks starting with most recent.
*/
public wherecmd()
{
walkstack(false);
}
/*
* Print the variables in the given frame or the current one if nil.
*/
public dump (func)
Symbol func;
{
Symbol f;
Frame frp;
if (func == nil) {
f = curfunc;
if (curframe != nil) {
frp = curframe;
} else {
frp = findframe(f);
}
} else {
f = func;
frp = findframe(f);
}
showaggrs = true;
printcallinfo(f, frp);
dumpvars(f, frp);
}
/*
* Dump all values.
*/
public dumpall ()
{
walkstack(true);
}
/*
* Walk the stack of active procedures printing information
* about each active procedure.
*/
private walkstack(dumpvariables)
Boolean dumpvariables;
{
Frame frp;
boolean save;
Symbol f;
struct Frame frame;
if (notstarted(process) or isfinished(process)) {
error("program is not active");
} else {
save = walkingstack;
walkingstack = true;
showaggrs = dumpvariables;
frp = &frame;
getcurfunc(frp, &f);
for (;;) {
printcallinfo(f, frp);
if (dumpvariables) {
dumpvars(f, frp);
putchar('\n');
}
frp = nextfunc(frp, &f);
if (frp == nil or f == program) {
break;
}
}
if (dumpvariables) {
printf("in \"%s\":\n", symname(program));
dumpvars(program, nil);
putchar('\n');
}
walkingstack = save;
}
}
/*
* Print out the information about a call, i.e.,
* routine name, parameter values, and source location.
*/
private printcallinfo (f, frp)
Symbol f;
Frame frp;
{
Lineno line;
Address savepc;
savepc = frp->save_pc;
if (frp->save_fp != reg(FRP)) {
savepc -= 1;
}
printname(stdout, f);
if (not isinline(f)) {
printparams(f, frp);
}
line = srcline(savepc);
if (line != 0) {
printf(", line %d", line);
printf(" in \"%s\"\n", srcfilename(savepc));
} else {
printf(" at 0x%x\n", savepc);
}
}
/*
* Set the current function to the given symbol.
* We must adjust "curframe" so that subsequent operations are
* not confused; for simplicity we simply clear it.
*/
public setcurfunc (f)
Symbol f;
{
curfunc = f;
curframe = nil;
}
/*
* Return the frame for the current function.
* The space for the frame is allocated statically.
*/
public Frame curfuncframe ()
{
static struct Frame frame;
Frame frp;
if (curframe == nil) {
frp = findframe(curfunc);
curframe = &curframerec;
*curframe = *frp;
} else {
frp = &frame;
*frp = *curframe;
}
return frp;
}
/*
* Set curfunc to be N up/down the stack from its current value.
*/
public up (n)
integer n;
{
integer i;
Symbol f;
Frame frp;
boolean done;
if (not isactive(program)) {
error("program is not active");
} else if (curfunc == nil) {
error("no current function");
} else {
i = 0;
f = curfunc;
frp = curfuncframe();
done = false;
do {
if (frp == nil) {
done = true;
error("not that many levels");
} else if (i >= n) {
done = true;
curfunc = f;
curframe = &curframerec;
*curframe = *frp;
showaggrs = false;
printcallinfo(curfunc, curframe);
} else if (f == program) {
done = true;
error("not that many levels");
} else {
frp = nextfunc(frp, &f);
}
++i;
} while (not done);
}
}
public down (n)
integer n;
{
integer i, depth;
Frame frp, curfrp;
Symbol f;
struct Frame frame;
if (not isactive(program)) {
error("program is not active");
} else if (curfunc == nil) {
error("no current function");
} else {
depth = 0;
frp = &frame;
getcurfunc(frp, &f);
if (curframe == nil) {
curfrp = findframe(curfunc);
curframe = &curframerec;
*curframe = *curfrp;
}
while ((f != curfunc or !frameeq(frp, curframe)) and f != nil) {
frp = nextfunc(frp, &f);
++depth;
}
if (f == nil or n > depth) {
error("not that many levels");
} else {
depth -= n;
frp = &frame;
getcurfunc(frp, &f);
for (i = 0; i < depth; i++) {
frp = nextfunc(frp, &f);
assert(frp != nil);
}
curfunc = f;
*curframe = *frp;
showaggrs = false;
printcallinfo(curfunc, curframe);
}
}
}
/*
* Find the entry point of a procedure or function.
*
* On the VAX we add the size of the register mask (FUNCOFFSET) or
* the size of the Modula-2 internal entry sequence, on other machines
* (68000's) we add the entry sequence size (FUNCOFFSET) unless
* we're right at the beginning of the program.
*/
public findbeginning (f)
Symbol f;
{
if (isinternal(f)) {
f->symvalue.funcv.beginaddr += 18; /* VAX only */
} else {
f->symvalue.funcv.beginaddr += FUNCOFFSET;
}
}
/*
* Return the address corresponding to the first line in a function.
*/
public Address firstline(f)
Symbol f;
{
Address addr;
addr = codeloc(f);
while (linelookup(addr) == 0 and addr < objsize) {
++addr;
}
if (addr == objsize) {
addr = -1;
}
return addr;
}
/*
* Catcher drops strike three ...
*/
public runtofirst()
{
Address addr, endaddr;
addr = pc;
endaddr = objsize + CODESTART;
while (linelookup(addr) == 0 and addr < endaddr) {
++addr;
}
if (addr < endaddr) {
stepto(addr);
}
}
/*
* Return the address corresponding to the end of the program.
*
* We look for the entry to "exit".
*/
public Address lastaddr()
{
Symbol s;
s = lookup(identname("exit", true));
if (s == nil) {
panic("can't find exit");
}
return codeloc(s);
}
/*
* Decide if the given function is currently active.
*
* We avoid calls to "findframe" during a stack trace for efficiency.
* Presumably information evaluated while walking the stack is active.
*/
public Boolean isactive (f)
Symbol f;
{
Boolean b;
if (isfinished(process)) {
b = false;
} else {
if (walkingstack or f == program or f == nil or
(ismodule(f) and isactive(container(f)))) {
b = true;
} else {
b = (Boolean) (findframe(f) != nil);
}
}
return b;
}
/*
* Evaluate a call to a procedure.
*/
public callproc(exprnode, isfunc)
Node exprnode;
boolean isfunc;
{
Node procnode, arglist;
Symbol proc;
integer argc;
procnode = exprnode->value.arg[0];
arglist = exprnode->value.arg[1];
if (procnode->op != O_SYM) {
beginerrmsg();
fprintf(stderr, "can't call \"");
prtree(stderr, procnode);
fprintf(stderr, "\"");
enderrmsg();
}
assert(procnode->op == O_SYM);
proc = procnode->value.sym;
if (not isblock(proc)) {
error("\"%s\" is not a procedure or function", symname(proc));
}
endproc.isfunc = isfunc;
endproc.callnode = exprnode;
endproc.cmdnode = topnode;
pushenv();
pc = codeloc(proc);
argc = pushargs(proc, arglist);
setreg(FRP, 1); /* have to ensure it's non-zero for return_addr() */
beginproc(proc, argc);
event_once(
build(O_EQ, build(O_SYM, pcsym), build(O_SYM, retaddrsym)),
buildcmdlist(build(O_PROCRTN, proc))
);
isstopped = false;
if (not bpact()) {
isstopped = true;
cont(0);
}
/*
* bpact() won't return true, it will call printstatus() and go back
* to command input if a breakpoint is found.
*/
/* NOTREACHED */
}
/*
* Push the arguments on the process' stack. We do this by first
* evaluating them on the "eval" stack, then copying into the process'
* space.
*/
private integer pushargs(proc, arglist)
Symbol proc;
Node arglist;
{
Stack *savesp;
int argc, args_size;
savesp = sp;
if (varIsSet("$unsafecall")) {
argc = unsafe_evalargs(proc, arglist);
} else {
argc = evalargs(proc, arglist);
}
args_size = sp - savesp;
setreg(STKP, reg(STKP) - args_size);
dwrite(savesp, reg(STKP), args_size);
sp = savesp;
return argc;
}
/*
* Check to see if an expression is correct for a given parameter.
* If the given parameter is false, don't worry about type inconsistencies.
*
* Return whether or not it is ok.
*/
private boolean chkparam (actual, formal, chk)
Node actual;
Symbol formal;
boolean chk;
{
boolean b;
b = true;
if (chk) {
if (formal == nil) {
beginerrmsg();
fprintf(stderr, "too many parameters");
b = false;
} else if (not compatible(formal->type, actual->nodetype)) {
beginerrmsg();
fprintf(stderr, "type mismatch for %s", symname(formal));
b = false;
}
}
if (b and formal != nil and
isvarparam(formal) and not isopenarray(formal->type) and
not (
actual->op == O_RVAL or actual->nodetype == t_addr or
(
actual->op == O_TYPERENAME and
(
actual->value.arg[0]->op == O_RVAL or
actual->value.arg[0]->nodetype == t_addr
)
)
)
) {
beginerrmsg();
fprintf(stderr, "expected variable, found \"");
prtree(stderr, actual);
fprintf(stderr, "\"");
b = false;
}
return b;
}
/*
* Pass an expression to a particular parameter.
*
* Normally we pass either the address or value, but in some cases
* (such as C strings) we want to copy the value onto the stack and
* pass its address.
*
* Another special case raised by strings is the possibility that
* the actual parameter will be larger than the formal, even with
* appropriate type-checking. This occurs because we assume during
* evaluation that strings are null-terminated, whereas some languages,
* notably Pascal, do not work under that assumption.
*/
private passparam (actual, formal)
Node actual;
Symbol formal;
{
boolean b;
Address addr;
Stack *savesp;
integer actsize, formsize;
if (formal != nil and isvarparam(formal) and
(not isopenarray(formal->type))
) {
addr = lval(actual->value.arg[0]);
push(Address, addr);
} else if (passaddr(formal, actual->nodetype)) {
savesp = sp;
eval(actual);
actsize = sp - savesp;
setreg(STKP,
reg(STKP) - ((actsize + sizeof(Word) - 1) & ~(sizeof(Word) - 1))
);
dwrite(savesp, reg(STKP), actsize);
sp = savesp;
push(Address, reg(STKP));
if (formal != nil and isopenarray(formal->type)) {
push(integer, actsize div size(formal->type->type));
}
} else if (formal != nil) {
formsize = size(formal);
savesp = sp;
eval(actual);
actsize = sp - savesp;
if (actsize > formsize) {
sp -= (actsize - formsize);
}
} else {
eval(actual);
}
}
/*
* Evaluate an argument list left-to-right.
*/
private integer evalargs(proc, arglist)
Symbol proc;
Node arglist;
{
Node p, actual;
Symbol formal;
Stack *savesp;
integer count;
boolean chk;
savesp = sp;
count = 0;
formal = proc->chain;
chk = (boolean) (not nosource(proc));
for (p = arglist; p != nil; p = p->value.arg[1]) {
assert(p->op == O_COMMA);
actual = p->value.arg[0];
if (not chkparam(actual, formal, chk)) {
fprintf(stderr, " in call to %s", symname(proc));
sp = savesp;
enderrmsg();
}
passparam(actual, formal);
if (formal != nil) {
formal = formal->chain;
}
++count;
}
if (chk) {
if (formal != nil) {
sp = savesp;
error("not enough parameters to %s", symname(proc));
}
}
return count;
}
/*
* Evaluate an argument list without any type checking.
* This is only useful for procedures with a varying number of
* arguments that are compiled -g.
*/
private integer unsafe_evalargs (proc, arglist)
Symbol proc;
Node arglist;
{
Node p;
integer count;
count = 0;
for (p = arglist; p != nil; p = p->value.arg[1]) {
assert(p->op == O_COMMA);
eval(p->value.arg[0]);
++count;
}
return count;
}
public procreturn(f)
Symbol f;
{
integer retvalsize;
Node tmp;
char *copy;
flushoutput();
popenv();
if (endproc.isfunc) {
retvalsize = size(f->type);
if (retvalsize > sizeof(long)) {
pushretval(retvalsize, true);
copy = newarr(char, retvalsize);
popn(retvalsize, copy);
tmp = build(O_SCON, copy);
} else {
tmp = build(O_LCON, (long) (reg(0)));
}
tmp->nodetype = f->type;
tfree(endproc.callnode);
*(endproc.callnode) = *(tmp);
dispose(tmp);
eval(endproc.cmdnode);
} else {
putchar('\n');
printname(stdout, f);
printf(" returns successfully\n");
}
erecover();
}
/*
* Push the current environment.
*/
private pushenv()
{
push(Address, pc);
push(Lineno, curline);
push(String, cursource);
push(Boolean, isstopped);
push(Symbol, curfunc);
push(Frame, curframe);
push(struct Frame, curframerec);
push(CallEnv, endproc);
push(Word, reg(PROGCTR));
push(Word, reg(STKP));
push(Word, reg(FRP));
}
/*
* Pop back to the real world.
*/
public popenv()
{
String filename;
setreg(FRP, pop(Word));
setreg(STKP, pop(Word));
setreg(PROGCTR, pop(Word));
endproc = pop(CallEnv);
curframerec = pop(struct Frame);
curframe = pop(Frame);
curfunc = pop(Symbol);
isstopped = pop(Boolean);
filename = pop(String);
curline = pop(Lineno);
pc = pop(Address);
setsource(filename);
}
/*
* Flush the debuggee's standard output.
*
* This is VERY dependent on the use of stdio.
*/
public flushoutput()
{
Symbol p, iob;
Stack *savesp;
p = lookup(identname("fflush", true));
while (p != nil and not isblock(p)) {
p = p->next_sym;
}
if (p != nil) {
iob = lookup(identname("__sF", true));
if (iob != nil) {
pushenv();
pc = codeloc(p) - FUNCOFFSET;
savesp = sp;
push(long, address(iob, nil) + sizeof(*stdout));
setreg(STKP, reg(STKP) - sizeof(long));
dwrite(savesp, reg(STKP), sizeof(long));
sp = savesp;
beginproc(p, 1);
stepto(return_addr());
popenv();
}
}
}