blob: 9496632c53244454fdc5c629ef7fcc8169780cab [file] [log] [blame]
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
/*
* code coverage
*/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include "tree.h"
#include <ureg_amd64.h>
#include <mach.h>
typedef struct Ureg Ureg;
void
usage(void)
{
fprint(2, "usage: cov [-lsv] [-g substring] [-m minlines] [6.out args...]\n");
fprint(2, "-g specifies pattern of interesting functions or files\n");
exits("usage");
}
typedef struct Range Range;
struct Range
{
uvlong pc;
uvlong epc;
};
int chatty;
int fd;
int longnames;
int pid;
int doshowsrc;
Map *mem;
Map *text;
Fhdr fhdr;
char *substring;
char cwd[1000];
int ncwd;
int minlines = -1000;
Tree breakpoints; // code ranges not run
/*
* comparison for Range structures
* they are "equal" if they overlap, so
* that a search for [pc, pc+1) finds the
* Range containing pc.
*/
int
rangecmp(void *va, void *vb)
{
Range *a = va, *b = vb;
if(a->epc <= b->pc)
return 1;
if(b->epc <= a->pc)
return -1;
return 0;
}
/*
* remember that we ran the section of code [pc, epc).
*/
void
ran(uvlong pc, uvlong epc)
{
Range key;
Range *r;
uvlong oldepc;
if(chatty)
print("run %#llux-%#llux\n", pc, epc);
key.pc = pc;
key.epc = pc+1;
r = treeget(&breakpoints, &key);
if(r == nil)
sysfatal("unchecked breakpoint at %#llux+%d", pc, (int)(epc-pc));
// Might be that the tail of the sequence
// was run already, so r->epc is before the end.
// Adjust len.
if(epc > r->epc)
epc = r->epc;
if(r->pc == pc) {
r->pc = epc;
} else {
// Chop r to before pc;
// add new entry for after if needed.
// Changing r->epc does not affect r's position in the tree.
oldepc = r->epc;
r->epc = pc;
if(epc < oldepc) {
Range *n;
n = malloc(sizeof *n);
n->pc = epc;
n->epc = oldepc;
treeput(&breakpoints, n, n);
}
}
}
void
showsrc(char *file, int line1, int line2)
{
Biobuf *b;
char *p;
int n, stop;
if((b = Bopen(file, OREAD)) == nil) {
print("\topen %s: %r\n", file);
return;
}
for(n=1; n<line1 && (p = Brdstr(b, '\n', 1)) != nil; n++)
free(p);
// print up to five lines (this one and 4 more).
// if there are more than five lines, print 4 and "..."
stop = n+4;
if(stop > line2)
stop = line2;
if(stop < line2)
stop--;
for(; n<=stop && (p = Brdstr(b, '\n', 1)) != nil; n++) {
print(" %d %s\n", n, p);
free(p);
}
if(n < line2)
print(" ...\n");
Bterm(b);
}
/*
* if s is in the current directory or below,
* return the relative path.
*/
char*
shortname(char *s)
{
if(!longnames && strlen(s) > ncwd && memcmp(s, cwd, ncwd) == 0 && s[ncwd] == '/')
return s+ncwd+1;
return s;
}
/*
* we've decided that [pc, epc) did not run.
* do something about it.
*/
void
missing(uvlong pc, uvlong epc)
{
char file[1000];
int line1, line2;
char buf[100];
Symbol s;
char *p;
uvlong uv;
if(!findsym(pc, CTEXT, &s) || !fileline(file, sizeof file, pc)) {
notfound:
print("%#llux-%#llux\n", pc, epc);
return;
}
p = strrchr(file, ':');
*p++ = 0;
line1 = atoi(p);
for(uv=pc; uv<epc; ) {
if(!fileline(file, sizeof file, epc-2))
goto notfound;
uv += machdata->instsize(text, uv);
}
p = strrchr(file, ':');
*p++ = 0;
line2 = atoi(p);
if(line2+1-line2 < minlines)
return;
if(pc == s.value) {
// never entered function
print("%s:%d %s never called (%#llux-%#llux)\n", shortname(file), line1, s.name, pc, epc);
return;
}
if(pc <= s.value+13) {
// probably stub for stack growth.
// check whether last instruction is call to morestack.
// the -5 below is the length of
// CALL sys.morestack.
buf[0] = 0;
machdata->das(text, epc-5, 0, buf, sizeof buf);
if(strstr(buf, "morestack"))
return;
}
if(epc - pc == 5) {
// check for CALL sys.panicindex
buf[0] = 0;
machdata->das(text, pc, 0, buf, sizeof buf);
if(strstr(buf, "panicindex"))
return;
}
if(epc - pc == 2 || epc -pc == 3) {
// check for XORL inside shift.
// (on x86 have to implement large left or unsigned right shift with explicit zeroing).
// f+90 0x00002c9f CMPL CX,$20
// f+93 0x00002ca2 JCS f+97(SB)
// f+95 0x00002ca4 XORL AX,AX <<<
// f+97 0x00002ca6 SHLL CL,AX
// f+99 0x00002ca8 MOVL $1,CX
//
// f+c8 0x00002cd7 CMPL CX,$40
// f+cb 0x00002cda JCS f+d0(SB)
// f+cd 0x00002cdc XORQ AX,AX <<<
// f+d0 0x00002cdf SHLQ CL,AX
// f+d3 0x00002ce2 MOVQ $1,CX
buf[0] = 0;
machdata->das(text, pc, 0, buf, sizeof buf);
if(strncmp(buf, "XOR", 3) == 0) {
machdata->das(text, epc, 0, buf, sizeof buf);
if(strncmp(buf, "SHL", 3) == 0 || strncmp(buf, "SHR", 3) == 0)
return;
}
}
if(epc - pc == 3) {
// check for SAR inside shift.
// (on x86 have to implement large signed right shift as >>31).
// f+36 0x00016216 CMPL CX,$20
// f+39 0x00016219 JCS f+3e(SB)
// f+3b 0x0001621b SARL $1f,AX <<<
// f+3e 0x0001621e SARL CL,AX
// f+40 0x00016220 XORL CX,CX
// f+42 0x00016222 CMPL CX,AX
buf[0] = 0;
machdata->das(text, pc, 0, buf, sizeof buf);
if(strncmp(buf, "SAR", 3) == 0) {
machdata->das(text, epc, 0, buf, sizeof buf);
if(strncmp(buf, "SAR", 3) == 0)
return;
}
}
// show first instruction to make clear where we were.
machdata->das(text, pc, 0, buf, sizeof buf);
if(line1 != line2)
print("%s:%d,%d %#llux-%#llux %s\n",
shortname(file), line1, line2, pc, epc, buf);
else
print("%s:%d %#llux-%#llux %s\n",
shortname(file), line1, pc, epc, buf);
if(doshowsrc)
showsrc(file, line1, line2);
}
/*
* walk the tree, calling missing for each non-empty
* section of missing code.
*/
void
walktree(TreeNode *t)
{
Range *n;
if(t == nil)
return;
walktree(t->left);
n = t->key;
if(n->pc < n->epc)
missing(n->pc, n->epc);
walktree(t->right);
}
/*
* set a breakpoint all over [pc, epc)
* and remember that we did.
*/
void
breakpoint(uvlong pc, uvlong epc)
{
Range *r;
r = malloc(sizeof *r);
r->pc = pc;
r->epc = epc;
treeput(&breakpoints, r, r);
for(; pc < epc; pc+=machdata->bpsize)
put1(mem, pc, machdata->bpinst, machdata->bpsize);
}
/*
* install breakpoints over all text symbols
* that match the pattern.
*/
void
cover(void)
{
Symbol s;
char *lastfn;
uvlong lastpc;
int i;
char buf[200];
lastfn = nil;
lastpc = 0;
for(i=0; textsym(&s, i); i++) {
switch(s.type) {
case 'T':
case 't':
if(lastpc != 0) {
breakpoint(lastpc, s.value);
lastpc = 0;
}
// Ignore second entry for a given name;
// that's the debugging blob.
if(lastfn && strcmp(s.name, lastfn) == 0)
break;
lastfn = s.name;
buf[0] = 0;
fileline(buf, sizeof buf, s.value);
if(substring == nil || strstr(buf, substring) || strstr(s.name, substring))
lastpc = s.value;
}
}
}
uvlong
rgetzero(Map *map, char *reg)
{
USED(map);
USED(reg);
return 0;
}
/*
* remove the breakpoints at pc and successive instructions,
* up to and including the first jump or other control flow transfer.
*/
void
uncover(uvlong pc)
{
uchar buf[1000];
int n, n1, n2;
uvlong foll[2];
// Double-check that we stopped at a breakpoint.
if(get1(mem, pc, buf, machdata->bpsize) < 0)
sysfatal("read mem inst at %#llux: %r", pc);
if(memcmp(buf, machdata->bpinst, machdata->bpsize) != 0)
sysfatal("stopped at %#llux; not at breakpoint %d", pc, machdata->bpsize);
// Figure out how many bytes of straight-line code
// there are in the text starting at pc.
n = 0;
while(n < sizeof buf) {
n1 = machdata->instsize(text, pc+n);
if(n+n1 > sizeof buf)
break;
n2 = machdata->foll(text, pc+n, rgetzero, foll);
n += n1;
if(n2 != 1 || foll[0] != pc+n)
break;
}
// Record that this section of code ran.
ran(pc, pc+n);
// Put original instructions back.
if(get1(text, pc, buf, n) < 0)
sysfatal("get1: %r");
if(put1(mem, pc, buf, n) < 0)
sysfatal("put1: %r");
}
int
startprocess(char **argv)
{
int pid;
if((pid = fork()) < 0)
sysfatal("fork: %r");
if(pid == 0) {
pid = getpid();
if(ctlproc(pid, "hang") < 0)
sysfatal("ctlproc hang: %r");
exec(argv[0], argv);
sysfatal("exec %s: %r", argv[0]);
}
if(ctlproc(pid, "attached") < 0 || ctlproc(pid, "waitstop") < 0)
sysfatal("attach %d %s: %r", pid, argv[0]);
return pid;
}
int
go(void)
{
uvlong pc;
char buf[100];
int n;
for(n = 0;; n++) {
ctlproc(pid, "startstop");
if(get8(mem, offsetof(Ureg, ip), &pc) < 0) {
rerrstr(buf, sizeof buf);
if(strstr(buf, "exited") || strstr(buf, "No such process"))
return n;
sysfatal("cannot read pc: %r");
}
pc--;
if(put8(mem, offsetof(Ureg, ip), pc) < 0)
sysfatal("cannot write pc: %r");
uncover(pc);
}
}
void
main(int argc, char **argv)
{
int n;
ARGBEGIN{
case 'g':
substring = EARGF(usage());
break;
case 'l':
longnames++;
break;
case 'n':
minlines = atoi(EARGF(usage()));
break;
case 's':
doshowsrc = 1;
break;
case 'v':
chatty++;
break;
default:
usage();
}ARGEND
getwd(cwd, sizeof cwd);
ncwd = strlen(cwd);
if(argc == 0) {
*--argv = "6.out";
}
fd = open(argv[0], OREAD);
if(fd < 0)
sysfatal("open %s: %r", argv[0]);
if(crackhdr(fd, &fhdr) <= 0)
sysfatal("crackhdr: %r");
machbytype(fhdr.type);
if(syminit(fd, &fhdr) <= 0)
sysfatal("syminit: %r");
text = loadmap(nil, fd, &fhdr);
if(text == nil)
sysfatal("loadmap: %r");
pid = startprocess(argv);
mem = attachproc(pid, &fhdr);
if(mem == nil)
sysfatal("attachproc: %r");
breakpoints.cmp = rangecmp;
cover();
n = go();
walktree(breakpoints.root);
if(chatty)
print("%d breakpoints\n", n);
detachproc(mem);
exits(0);
}