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use pc/ln table to print source lines in traceback

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r45=; 6.out
oops
panic PC=0x400316
0x400316?zi /home/rsc/go/src/runtime/rt0_amd64_linux.s:83
	main·g(4195177, 0, 4205661, ...)
	main·g(0x400369, 0x402c5d, 0x403e49, ...)
0x40034c?zi /home/rsc/go/src/runtime/x.go:24
	main·f(4205661, 0, 4210249, ...)
	main·f(0x402c5d, 0x403e49, 0x1, ...)
0x400368?zi /home/rsc/go/src/runtime/x.go:37
	main·main(4210249, 0, 1, ...)
	main·main(0x403e49, 0x1, 0x7fff9d894bd8, ...)
0x402c5c?zi /home/rsc/go/src/runtime/rt0_amd64.s:70
	mainstart(1, 0, 2643020760, ...)
	mainstart(0x1, 0x7fff9d894bd8, 0x0, ...)
r45=;

R=r
DELTA=251  (198 added, 25 deleted, 28 changed)
OCL=19965
CL=19979
This commit is contained in:
Russ Cox 2008-11-25 09:23:36 -08:00
parent afff0ff1b8
commit a5433369aa
3 changed files with 222 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/runtime/rt2_amd64.c
View File

@ -11,8 +11,6 @@ extern uint8 end;
void
traceback(uint8 *pc, uint8 *sp, void* r15)
{
int32 spoff;
int8* spp;
uint8* callpc;
int32 counter;
int32 i;
@ -60,7 +58,11 @@ traceback(uint8 *pc, uint8 *sp, void* r15)
/* print this frame */
prints("0x");
sys·printpointer(callpc - 1); // -1 to get to CALL instr.
prints("?zi\n");
prints("?zi ");
sys·printstring(f->src);
prints(":");
sys·printint(funcline(f, (uint64)callpc-1)); // -1 to get to CALL instr.
prints("\n");
prints("\t");
sys·printstring(name);
prints("(");

11
src/runtime/runtime.h
View File

@ -189,9 +189,13 @@ struct SigTab
struct Func
{
string name;
string type;
uint64 entry;
int64 frame;
string type; // go type string
string src; // src file name
uint64 entry; // entry pc
int64 frame; // stack frame size
Array pcln; // pc/ln tab for this func
int64 pc0; // starting pc, ln for table
int32 ln0;
};
/*
@ -261,6 +265,7 @@ void signalstack(byte*, int32);
G* malg(int32);
void minit(void);
Func* findfunc(uint64);
int32 funcline(Func*, uint64);
/*
* mutual exclusion locks. in the uncontended case,

252
src/runtime/symtab.c
View File

@ -2,21 +2,22 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "runtime.h"
// Runtime symbol table access. Work in progress.
// The Plan 9 symbol table is not in a particularly convenient form.
// The routines here massage it into a more usable form; eventually
// we'll change 6l to do this for us, but it is easier to experiment
// here than to change 6l and all the other tools.
//
// The symbol table also needs to be better integrated with the type
// strings table in the future. This is just a quick way to get started
// and figure out exactly what we want.
// Runtime symbol table access.
// Very much a work in progress.
#include "runtime.h"
#define SYMCOUNTS ((int32*)(0x99LL<<32)) // known to 6l
#define SYMDATA ((byte*)(0x99LL<<32) + 8)
// Return a pointer to a byte array containing the symbol table segment.
//
// NOTE(rsc): I expect that we will clean up both the method of getting
// at the symbol table and the exact format of the symbol table at some
// point in the future. It probably needs to be better integrated with
// the type strings table too. This is just a quick way to get started
// and figure out what we want from/can do with it.
void
sys·symdat(Array *symtab, Array *pclntab)
{
@ -50,7 +51,7 @@ struct Sym
};
// Walk over symtab, calling fn(&s) for each symbol.
void
static void
walksymtab(void (*fn)(Sym*))
{
int32 *v;
@ -68,10 +69,10 @@ walksymtab(void (*fn)(Sym*))
break;
s.symtype = p[4] & ~0x80;
p += 5;
s.name = p;
if(s.symtype == 'z' || s.symtype == 'Z') {
// path reference string - skip first byte,
// then 2-byte pairs ending at two zeros.
// for now, just skip over it and ignore it.
q = p+1;
for(;;) {
if(q+2 > ep)
@ -81,12 +82,10 @@ walksymtab(void (*fn)(Sym*))
q += 2;
}
p = q+2;
s.name = nil;
}else{
q = mchr(p, '\0', ep);
if(q == nil)
break;
s.name = p;
p = q+1;
}
q = mchr(p, '\0', ep);
@ -100,33 +99,198 @@ walksymtab(void (*fn)(Sym*))
// Symtab walker; accumulates info about functions.
Func *func;
int32 nfunc;
static Func *func;
static int32 nfunc;
static byte **fname;
static int32 nfname;
static void
dofunc(Sym *sym)
{
static byte *lastfuncname;
static Func *lastfunc;
Func *f;
if(lastfunc && sym->symtype == 'm') {
lastfunc->frame = sym->value;
return;
}
if(sym->symtype != 'T' && sym->symtype != 't')
return;
if(strcmp(sym->name, (byte*)"etext") == 0)
return;
if(func == nil) {
nfunc++;
return;
switch(sym->symtype) {
case 't':
case 'T':
if(strcmp(sym->name, (byte*)"etext") == 0)
break;
if(func == nil) {
nfunc++;
break;
}
f = &func[nfunc++];
f->name = gostring(sym->name);
f->entry = sym->value;
break;
case 'm':
if(nfunc > 0 && func != nil)
func[nfunc-1].frame = sym->value;
break;
case 'f':
if(fname == nil) {
if(sym->value >= nfname)
nfname = sym->value+1;
break;
}
fname[sym->value] = sym->name;
break;
}
}
f = &func[nfunc++];
f->name = gostring(sym->name);
f->entry = sym->value;
lastfunc = f;
// put together the path name for a z entry.
// the f entries have been accumulated into fname already.
static void
makepath(byte *buf, int32 nbuf, byte *path)
{
int32 n, len;
byte *p, *ep, *q;
if(nbuf <= 0)
return;
p = buf;
ep = buf + nbuf;
*p = '\0';
for(;;) {
if(path[0] == 0 && path[1] == 0)
break;
n = (path[0]<<8) | path[1];
path += 2;
if(n >= nfname)
break;
q = fname[n];
len = findnull(q);
if(p+1+len >= ep)
break;
if(p > buf && p[-1] != '/')
*p++ = '/';
mcpy(p, q, len+1);
p += len;
}
}
// walk symtab accumulating path names for use by pc/ln table.
// don't need the full generality of the z entry history stack because
// there are no includes in go (and only sensible includes in our c).
static void
dosrcline(Sym *sym)
{
static byte srcbuf[1000];
static string srcstring;
static int32 lno, incstart;
static int32 nf, nhist;
Func *f;
switch(sym->symtype) {
case 't':
case 'T':
f = &func[nf++];
f->src = srcstring;
f->ln0 += lno;
break;
case 'z':
if(sym->value == 1) {
// entry for main source file for a new object.
makepath(srcbuf, sizeof srcbuf, sym->name+1);
srcstring = gostring(srcbuf);
lno = 0;
nhist = 0;
} else {
// push or pop of included file.
makepath(srcbuf, sizeof srcbuf, sym->name+1);
if(srcbuf[0] != '\0') {
if(nhist++ == 0)
incstart = sym->value;
}else{
if(--nhist == 0)
lno -= sym->value - incstart;
}
}
}
}
enum { PcQuant = 1 };
// Interpret pc/ln table, saving the subpiece for each func.
static void
splitpcln(void)
{
int32 line;
uint64 pc;
byte *p, *ep;
Func *f, *ef;
int32 *v;
// pc/ln table bounds
v = SYMCOUNTS;
p = SYMDATA;
p += v[0];
ep = p+v[1];
f = func;
ef = func + nfunc;
f->pcln.array = p;
pc = func[0].entry; // text base
line = 0;
for(; p < ep; p++) {
if(f < ef && pc >= (f+1)->entry) {
f->pcln.nel = p - f->pcln.array;
f->pcln.cap = f->pcln.nel;
f++;
f->pcln.array = p;
f->pc0 = pc;
f->ln0 = line;
}
if(*p == 0) {
// 4 byte add to line
line += (p[1]<<24) | (p[2]<<16) | (p[3]<<8) | p[4];
p += 4;
} else if(*p <= 64) {
line += *p;
} else if(*p <= 128) {
line -= *p - 64;
} else {
pc += PcQuant*(*p - 129);
}
pc += PcQuant;
}
if(f < ef) {
f->pcln.nel = p - f->pcln.array;
f->pcln.cap = f->pcln.nel;
}
}
// Return actual file line number for targetpc in func f.
// (Source file is f->src.)
int32
funcline(Func *f, uint64 targetpc)
{
byte *p, *ep;
uint64 pc;
int32 line;
p = f->pcln.array;
ep = p + f->pcln.nel;
pc = f->pc0;
line = f->ln0;
for(; p < ep; p++) {
if(pc >= targetpc)
return line;
if(*p == 0) {
line += (p[1]<<24) | (p[2]<<16) | (p[3]<<8) | p[4];
p += 4;
} else if(*p <= 64) {
line += *p;
} else if(*p <= 128) {
line -= *p - 64;
} else {
pc += PcQuant*(*p - 129);
}
pc += PcQuant;
}
return line;
}
static void
@ -136,19 +300,30 @@ buildfuncs(void)
if(func != nil)
return;
// count funcs, fnames
nfunc = 0;
nfname = 0;
walksymtab(dofunc);
// initialize tables
func = mal((nfunc+1)*sizeof func[0]);
func[nfunc].entry = (uint64)etext;
fname = mal(nfname*sizeof fname[0]);
nfunc = 0;
walksymtab(dofunc);
func[nfunc].entry = (uint64)etext;
// split pc/ln table by func
splitpcln();
// record src file and line info for each func
walksymtab(dosrcline);
}
Func*
findfunc(uint64 addr)
{
Func *f;
int32 i, nf, n;
int32 nf, n;
if(func == nil)
buildfuncs();
@ -157,15 +332,6 @@ findfunc(uint64 addr)
if(addr < func[0].entry || addr >= func[nfunc].entry)
return nil;
// linear search, for debugging
if(0) {
for(i=0; i<nfunc; i++) {
if(func[i].entry <= addr && addr < func[i+1].entry)
return &func[i];
}
return nil;
}
// binary search to find func with entry <= addr.
f = func;
nf = nfunc;