mirror of
https://github.com/reactos/reactos.git
synced 2024-11-07 15:10:53 +00:00
407 lines
8.6 KiB
C
407 lines
8.6 KiB
C
/*
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* Dwarf call frame unwinding.
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*
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* The call frame unwinding values are encoded using a state machine
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* like the pc<->line mapping, but it's a different machine.
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* The expressions to generate the old values are similar in function to the
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* ``dwarf expressions'' used for locations in the code, but of course not
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* the same encoding.
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*/
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#define NTOSAPI
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#include <ntddk.h>
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#include <reactos/rossym.h>
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#include "rossympriv.h"
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#include <ntimage.h>
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#define NDEBUG
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#include <debug.h>
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#include "dwarf.h"
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#define trace 0
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typedef struct State State;
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struct State
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{
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ulong loc;
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ulong endloc;
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ulong iquantum;
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ulong dquantum;
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char *augmentation;
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int version;
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ulong rareg;
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DwarfBuf init;
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DwarfExpr *cfa;
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DwarfExpr *ra;
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DwarfExpr *r;
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DwarfExpr *initr;
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int nr;
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DwarfExpr **stack;
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int nstack;
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};
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static int findfde(Dwarf*, ulong, State*, DwarfBuf*);
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static int dexec(DwarfBuf*, State*, int);
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int
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dwarfunwind(Dwarf *d, ulong pc, DwarfExpr *cfa, DwarfExpr *ra, DwarfExpr *r, int nr)
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{
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int i, ret;
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DwarfBuf fde, b;
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DwarfExpr *initr;
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State s;
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initr = mallocz(nr*sizeof(initr[0]), 1);
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if(initr == 0)
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return -1;
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memset(&s, 0, sizeof s);
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s.loc = 0;
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s.cfa = cfa;
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s.ra = ra;
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s.r = r;
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s.nr = nr;
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if(findfde(d, pc, &s, &fde) < 0){
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free(initr);
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return -1;
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}
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memset(r, 0, nr*sizeof(r[0]));
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for(i=0; i<nr; i++)
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r[i].type = RuleSame;
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if(trace) werrstr("s.init %p-%p, fde %p-%p\n", s.init.p, s.init.ep, fde.p, fde.ep);
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b = s.init;
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if(dexec(&b, &s, 0) < 0)
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goto err;
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s.initr = initr;
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memmove(initr, r, nr*sizeof(initr[0]));
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if(trace) werrstr("s.loc 0x%lux pc 0x%lux\n", s.loc, pc);
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while(s.loc < pc){
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if(trace) werrstr("s.loc 0x%lux pc 0x%lux\n", s.loc, pc);
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if(dexec(&fde, &s, 1) < 0)
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goto err;
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}
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*ra = s.r[s.rareg];
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ret = 0;
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goto out;
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err:
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ret = -1;
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out:
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free(initr);
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for(i=0; i<s.nstack; i++)
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free(s.stack[i]);
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free(s.stack);
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return ret;
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}
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/*
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* XXX This turns out to be much more expensive than the actual
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* running of the machine in dexec. It probably makes sense to
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* cache the last 10 or so fde's we've found, since stack traces
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* will keep asking for the same info over and over.
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*/
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static int
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findfde(Dwarf *d, ulong pc, State *s, DwarfBuf *fde)
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{
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static int nbad;
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char *aug;
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uchar *next;
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int i, vers;
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ulong len, id, base, size;
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DwarfBuf b;
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if(d->frame.data == nil){
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werrstr("no frame debugging information");
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return -1;
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}
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b.d = d;
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b.p = d->frame.data;
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b.ep = b.p + d->frame.len;
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b.addrsize = d->addrsize;
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if(b.addrsize == 0)
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b.addrsize = 4; /* where should i find this? */
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for(; b.p < b.ep; b.p = next){
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if((i = (b.p - d->frame.data) % b.addrsize))
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b.p += b.addrsize - i;
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len = dwarfget4(&b);
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if(len > b.ep-b.p){
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werrstr("bad length in cie/fde header");
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return -1;
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}
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next = b.p+len;
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id = dwarfget4(&b);
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if(id == 0xFFFFFFFF){ /* CIE */
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vers = dwarfget1(&b);
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if(vers != 1 && vers != 2 && vers != 3){
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if(++nbad == 1)
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werrstr("unknown cie version %d (wanted 1-3)\n", vers);
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continue;
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}
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aug = dwarfgetstring(&b);
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if(aug && *aug){
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if(++nbad == 1)
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werrstr("unknown augmentation: %s\n", aug);
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continue;
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}
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s->iquantum = dwarfget128(&b);
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s->dquantum = dwarfget128s(&b);
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s->rareg = dwarfget128(&b);
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if(s->rareg > s->nr){
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werrstr("return address is register %d but only have %d registers",
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s->rareg, s->nr);
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return -1;
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}
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s->init.p = b.p;
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s->init.ep = next;
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}else{ /* FDE */
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base = dwarfgetaddr(&b);
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size = dwarfgetaddr(&b);
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fde->p = b.p;
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fde->ep = next;
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s->loc = base;
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s->endloc = base+size;
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if(base <= pc && pc < base+size)
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return 0;
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}
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}
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werrstr("cannot find call frame information for pc 0x%lux", pc);
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return -1;
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}
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static int
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checkreg(State *s, long r)
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{
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if(r < 0 || r >= s->nr){
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werrstr("bad register number 0x%lux", r);
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return -1;
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}
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return 0;
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}
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static int
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dexec(DwarfBuf *b, State *s, int locstop)
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{
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int c;
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long arg1, arg2;
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DwarfExpr *e;
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for(;;){
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if(b->p == b->ep){
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if(s->initr)
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s->loc = s->endloc;
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return 0;
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}
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c = dwarfget1(b);
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if(b->p == nil){
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werrstr("ran out of instructions during cfa program");
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if(trace) werrstr("%r\n");
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return -1;
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}
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if(trace) werrstr("+ loc=0x%lux op 0x%ux ", s->loc, c);
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switch(c>>6){
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case 1: /* advance location */
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arg1 = c&0x3F;
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advance:
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if(trace) werrstr("loc += %ld\n", arg1*s->iquantum);
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s->loc += arg1 * s->iquantum;
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if(locstop)
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return 0;
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continue;
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case 2: /* offset rule */
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arg1 = c&0x3F;
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arg2 = dwarfget128(b);
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offset:
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if(trace) werrstr("r%ld += %ld\n", arg1, arg2*s->dquantum);
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if(checkreg(s, arg1) < 0)
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return -1;
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s->r[arg1].type = RuleCfaOffset;
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s->r[arg1].offset = arg2 * s->dquantum;
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continue;
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case 3: /* restore initial setting */
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arg1 = c&0x3F;
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restore:
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if(trace) werrstr("r%ld = init\n", arg1);
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if(checkreg(s, arg1) < 0)
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return -1;
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s->r[arg1] = s->initr[arg1];
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continue;
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}
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switch(c){
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case 0: /* nop */
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if(trace) werrstr("nop\n");
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continue;
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case 0x01: /* set location */
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s->loc = dwarfgetaddr(b);
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if(trace) werrstr("loc = 0x%lux\n", s->loc);
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if(locstop)
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return 0;
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continue;
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case 0x02: /* advance loc1 */
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arg1 = dwarfget1(b);
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goto advance;
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case 0x03: /* advance loc2 */
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arg1 = dwarfget2(b);
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goto advance;
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case 0x04: /* advance loc4 */
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arg1 = dwarfget4(b);
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goto advance;
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case 0x05: /* offset extended */
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arg1 = dwarfget128(b);
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arg2 = dwarfget128(b);
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goto offset;
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case 0x06: /* restore extended */
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arg1 = dwarfget128(b);
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goto restore;
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case 0x07: /* undefined */
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arg1 = dwarfget128(b);
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if(trace) werrstr("r%ld = undef\n", arg1);
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if(checkreg(s, arg1) < 0)
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return -1;
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s->r[arg1].type = RuleUndef;
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continue;
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case 0x08: /* same value */
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arg1 = dwarfget128(b);
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if(trace) werrstr("r%ld = same\n", arg1);
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if(checkreg(s, arg1) < 0)
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return -1;
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s->r[arg1].type = RuleSame;
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continue;
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case 0x09: /* register */
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arg1 = dwarfget128(b);
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arg2 = dwarfget128(b);
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if(trace) werrstr("r%ld = r%ld\n", arg1, arg2);
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if(checkreg(s, arg1) < 0 || checkreg(s, arg2) < 0)
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return -1;
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s->r[arg1].type = RuleRegister;
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s->r[arg1].reg = arg2;
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continue;
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case 0x0A: /* remember state */
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e = malloc(s->nr*sizeof(e[0]));
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if(trace) werrstr("push\n");
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if(e == nil)
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return -1;
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void *newstack = malloc(s->nstack*sizeof(s->stack[0]));
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RtlMoveMemory(newstack, s->stack, s->nstack*sizeof(s->stack[0]));
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if (newstack) {
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free(s->stack);
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s->stack = newstack;
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} else {
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free(e);
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return -1;
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}
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if(b->p == nil){
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free(e);
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return -1;
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}
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s->stack[s->nstack++] = e;
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memmove(e, s->r, s->nr*sizeof(e[0]));
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continue;
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case 0x0B: /* restore state */
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if(trace) werrstr("pop\n");
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if(s->nstack == 0){
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werrstr("restore state underflow");
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return -1;
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}
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e = s->stack[s->nstack-1];
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memmove(s->r, e, s->nr*sizeof(e[0]));
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free(e);
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s->nstack--;
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continue;
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case 0x0C: /* def cfa */
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arg1 = dwarfget128(b);
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arg2 = dwarfget128(b);
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defcfa:
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if(trace) werrstr("cfa %ld(r%ld)\n", arg2, arg1);
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if(checkreg(s, arg1) < 0)
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return -1;
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s->cfa->type = RuleRegOff;
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s->cfa->reg = arg1;
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s->cfa->offset = arg2;
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continue;
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case 0x0D: /* def cfa register */
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arg1 = dwarfget128(b);
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if(trace) werrstr("cfa reg r%ld\n", arg1);
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if(s->cfa->type != RuleRegOff){
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werrstr("change CFA register but CFA not in register+offset form");
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return -1;
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}
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if(checkreg(s, arg1) < 0)
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return -1;
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s->cfa->reg = arg1;
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continue;
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case 0x0E: /* def cfa offset */
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arg1 = dwarfget128(b);
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cfaoffset:
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if(trace) werrstr("cfa off %ld\n", arg1);
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if(s->cfa->type != RuleRegOff){
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werrstr("change CFA offset but CFA not in register+offset form");
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return -1;
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}
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s->cfa->offset = arg1;
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continue;
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case 0x0F: /* def cfa expression */
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if(trace) werrstr("cfa expr\n");
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s->cfa->type = RuleLocation;
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s->cfa->loc.len = dwarfget128(b);
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s->cfa->loc.data = dwarfgetnref(b, s->cfa->loc.len);
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continue;
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case 0x10: /* def reg expression */
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arg1 = dwarfget128(b);
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if(trace) werrstr("reg expr r%ld\n", arg1);
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if(checkreg(s, arg1) < 0)
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return -1;
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s->r[arg1].type = RuleLocation;
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s->r[arg1].loc.len = dwarfget128(b);
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s->r[arg1].loc.data = dwarfgetnref(b, s->r[arg1].loc.len);
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continue;
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case 0x11: /* offset extended */
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arg1 = dwarfget128(b);
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arg2 = dwarfget128s(b);
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goto offset;
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case 0x12: /* cfa sf */
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arg1 = dwarfget128(b);
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arg2 = dwarfget128s(b);
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goto defcfa;
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case 0x13: /* cfa offset sf */
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arg1 = dwarfget128s(b);
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goto cfaoffset;
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default: /* unknown */
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werrstr("unknown opcode 0x%ux in cfa program", c);
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return -1;
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}
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}
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/* not reached */
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}
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