libmach

src/libmach/frame.c

@@ -0,0 +1,130 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <mach.h>
+
+typedef struct LocRegs LocRegs;
+struct LocRegs
+{
+	Regs r;
+	Regs *oldregs;
+	Map *map;
+	ulong *val;
+};
+
+static int
+locregrw(Regs *regs, char *name, ulong *val, int isr)
+{
+	int i;
+	LocRegs *lr;
+
+	lr = (LocRegs*)regs;
+	i = windindex(name);
+	if(i == -1)
+		return lr->oldregs->rw(lr->oldregs, name, val, isr);
+	if(isr){
+		*val = lr->val[i];
+		return 0;
+	}else{
+		werrstr("saved registers are immutable");
+		return -1;
+	}
+}
+
+int
+stacktrace(Map *map, Regs *regs, Tracer trace)
+{
+	char *rname;
+	int i, ipc, ret;
+	ulong nextpc, pc, v;
+	ulong *cur, *next;
+	LocRegs lr;
+	Symbol s, *sp;
+
+	/*
+	 * Allocate location arrays.
+	 */
+	ret = -1;
+	cur = malloc(mach->nwindreg*sizeof(cur[0]));
+	next = malloc(mach->nwindreg*sizeof(cur[0]));
+	if(cur==nil || next==nil)
+		goto out;
+	
+	/*
+	 * Initialize current registers using regs.
+	 */
+	if(rget(regs, mach->pc, &pc) < 0){
+		werrstr("cannot fetch initial pc: %r");
+		goto out;	
+	}
+
+	for(i=0; i<mach->nwindreg; i++){
+		rname = mach->windreg[i];
+		if(rget(regs, rname, &v) < 0)
+			v = ~(ulong)0;
+		cur[i] = v;
+	}
+
+	ipc = windindex(mach->pc);
+	ret = 0;
+
+	/* set up cur[i]==next[i] for unwindframe */
+	memmove(next, cur, mach->nwindreg*sizeof(next[0]));
+	for(;;){
+		sp = &s;
+		if(findsym(locaddr(pc), CTEXT, &s) < 0)
+			sp = nil;
+
+		lr.r.rw = locregrw;
+		lr.oldregs = regs;
+		lr.val = cur;
+		lr.map = map;
+		if((i = unwindframe(map, &lr.r, next)) >= 0)
+			nextpc = next[ipc];
+		else
+			nextpc = ~(ulong)0;
+		if((*trace)(map, &lr.r, pc, nextpc, sp, ++ret) <= 0)
+			break;
+		if(i < 0)
+			break;
+		if(sp && strcmp(sp->name, "main") == 0)
+			break;
+		pc = nextpc;
+		memmove(cur, next, mach->nwindreg*sizeof(cur[0]));
+	}
+
+out:
+	free(cur);
+	free(next);
+	return ret;
+}
+
+int
+windindex(char *reg)
+{
+	char **p;
+	int i;
+
+	p = mach->windreg;
+	for(i=0; i<mach->nwindreg; i++)
+		if(strcmp(p[i], reg) == 0)
+			return i;
+	werrstr("%s is not a winding register", reg);
+	return -1;
+}
+
+Loc*
+windreglocs(void)
+{
+	int i;
+	Loc *loc;
+
+	loc = malloc(mach->nwindreg*sizeof(loc[0]));
+	if(loc == nil)
+		return nil;
+	for(i=0; i<mach->nwindreg; i++){
+		loc[i].type = LREG;
+		loc[i].reg = mach->windreg[i];
+	}
+	return loc;
+}