perf probe: Introduce kprobe_trace_event and perf_probe_event

Introduce kprobe_trace_event and perf_probe_event and replace
old probe_point structure with it. probe_point structure is
not enough flexible nor extensible. New data structures
will help implementing further features.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100316220612.32050.33806.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 63 insertions, 77 deletions

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 3942e14e95cf..251b4c49653e 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -319,19 +319,20 @@ static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
  */
 
 /* Show a location */
-static void show_location(Dwarf_Op *op, struct probe_finder *pf)
+static void convert_location(Dwarf_Op *op, struct probe_finder *pf)
 {
         unsigned int regn;
         Dwarf_Word offs = 0;
-        int deref = 0, ret;
+        bool ref = false;
         const char *regs;
+        struct kprobe_trace_arg *tvar = pf->tvar;
 
         /* TODO: support CFA */
         /* If this is based on frame buffer, set the offset */
         if (op->atom == DW_OP_fbreg) {
                 if (pf->fb_ops == NULL)
                         die("The attribute of frame base is not supported.\n");
-                deref = 1;
+                ref = true;
                 offs = op->number;
                 op = &pf->fb_ops[0];
         }
@@ -339,13 +340,13 @@ static void show_location(Dwarf_Op *op, struct probe_finder *pf)
         if (op->atom >= DW_OP_breg0 && op->atom <= DW_OP_breg31) {
                 regn = op->atom - DW_OP_breg0;
                 offs += op->number;
-                deref = 1;
+                ref = true;
         } else if (op->atom >= DW_OP_reg0 && op->atom <= DW_OP_reg31) {
                 regn = op->atom - DW_OP_reg0;
         } else if (op->atom == DW_OP_bregx) {
                 regn = op->number;
                 offs += op->number2;
-                deref = 1;
+                ref = true;
         } else if (op->atom == DW_OP_regx) {
                 regn = op->number;
         } else
@@ -355,17 +356,15 @@ static void show_location(Dwarf_Op *op, struct probe_finder *pf)
         if (!regs)
                 die("%u exceeds max register number.", regn);
 
-        if (deref)
-                ret = snprintf(pf->buf, pf->len, " %s=%+jd(%s)",
-                               pf->var, (intmax_t)offs, regs);
-        else
-                ret = snprintf(pf->buf, pf->len, " %s=%s", pf->var, regs);
-        DIE_IF(ret < 0);
-        DIE_IF(ret >= pf->len);
+        tvar->value = xstrdup(regs);
+        if (ref) {
+                tvar->ref = xzalloc(sizeof(struct kprobe_trace_arg_ref));
+                tvar->ref->offset = (long)offs;
+        }
 }
 
 /* Show a variables in kprobe event format */
-static void show_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
+static void convert_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
 {
         Dwarf_Attribute attr;
         Dwarf_Op *expr;
@@ -379,50 +378,51 @@ static void show_variable(Dwarf_Die *vr_die, struct probe_finder *pf)
         if (ret <= 0 || nexpr == 0)
                 goto error;
 
-        show_location(expr, pf);
+        convert_location(expr, pf);
         /* *expr will be cached in libdw. Don't free it. */
         return ;
 error:
         /* TODO: Support const_value */
         die("Failed to find the location of %s at this address.\n"
-            " Perhaps, it has been optimized out.", pf->var);
+            " Perhaps, it has been optimized out.", pf->pvar->name);
 }
 
 /* Find a variable in a subprogram die */
 static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 {
-        int ret;
         Dwarf_Die vr_die;
 
         /* TODO: Support struct members and arrays */
-        if (!is_c_varname(pf->var)) {
-                /* Output raw parameters */
-                ret = snprintf(pf->buf, pf->len, " %s", pf->var);
-                DIE_IF(ret < 0);
-                DIE_IF(ret >= pf->len);
-                return ;
+        if (!is_c_varname(pf->pvar->name)) {
+                /* Copy raw parameters */
+                pf->tvar->value = xstrdup(pf->pvar->name);
+        } else {
+                pf->tvar->name = xstrdup(pf->pvar->name);
+                pr_debug("Searching '%s' variable in context.\n",
+                         pf->pvar->name);
+                /* Search child die for local variables and parameters. */
+                if (!die_find_variable(sp_die, pf->pvar->name, &vr_die))
+                        die("Failed to find '%s' in this function.",
+                            pf->pvar->name);
+                convert_variable(&vr_die, pf);
         }
-
-        pr_debug("Searching '%s' variable in context.\n", pf->var);
-        /* Search child die for local variables and parameters. */
-        if (!die_find_variable(sp_die, pf->var, &vr_die))
-                die("Failed to find '%s' in this function.", pf->var);
-
-        show_variable(&vr_die, pf);
 }
 
 /* Show a probe point to output buffer */
-static void show_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
+static void convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
 {
-        struct probe_point *pp = pf->pp;
+        struct kprobe_trace_event *tev;
         Dwarf_Addr eaddr;
         Dwarf_Die die_mem;
         const char *name;
-        char tmp[MAX_PROBE_BUFFER];
-        int ret, i, len;
+        int ret, i;
         Dwarf_Attribute fb_attr;
         size_t nops;
 
+        if (pf->ntevs == MAX_PROBES)
+                die("Too many( > %d) probe point found.\n", MAX_PROBES);
+        tev = &pf->tevs[pf->ntevs++];
+
         /* If no real subprogram, find a real one */
         if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
                 sp_die = die_find_real_subprogram(&pf->cu_die,
@@ -431,31 +431,18 @@ static void show_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
                         die("Probe point is not found in subprograms.");
         }
 
-        /* Output name of probe point */
+        /* Copy the name of probe point */
         name = dwarf_diename(sp_die);
         if (name) {
                 dwarf_entrypc(sp_die, &eaddr);
-                ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%lu", name,
-                                (unsigned long)(pf->addr - eaddr));
-                /* Copy the function name if possible */
-                if (!pp->function) {
-                        pp->function = xstrdup(name);
-                        pp->offset = (size_t)(pf->addr - eaddr);
-                }
-        } else {
+                tev->point.symbol = xstrdup(name);
+                tev->point.offset = (unsigned long)(pf->addr - eaddr);
+        } else
                 /* This function has no name. */
-                ret = snprintf(tmp, MAX_PROBE_BUFFER, "0x%jx",
-                               (uintmax_t)pf->addr);
-                if (!pp->function) {
-                        /* TODO: Use _stext */
-                        pp->function = xstrdup("");
-                        pp->offset = (size_t)pf->addr;
-                }
-        }
-        DIE_IF(ret < 0);
-        DIE_IF(ret >= MAX_PROBE_BUFFER);
-        len = ret;
-        pr_debug("Probe point found: %s\n", tmp);
+                tev->point.offset = (unsigned long)pf->addr;
+
+        pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
+                 tev->point.offset);
 
         /* Get the frame base attribute/ops */
         dwarf_attr(sp_die, DW_AT_frame_base, &fb_attr);
@@ -465,22 +452,16 @@ static void show_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
 
         /* Find each argument */
         /* TODO: use dwarf_cfi_addrframe */
-        for (i = 0; i < pp->nr_args; i++) {
-                pf->var = pp->args[i];
-                pf->buf = &tmp[len];
-                pf->len = MAX_PROBE_BUFFER - len;
+        tev->nargs = pf->pev->nargs;
+        tev->args = xzalloc(sizeof(struct kprobe_trace_arg) * tev->nargs);
+        for (i = 0; i < pf->pev->nargs; i++) {
+                pf->pvar = &pf->pev->args[i];
+                pf->tvar = &tev->args[i];
                 find_variable(sp_die, pf);
-                len += strlen(pf->buf);
         }
 
         /* *pf->fb_ops will be cached in libdw. Don't free it. */
         pf->fb_ops = NULL;
-
-        if (pp->found == MAX_PROBES)
-                die("Too many( > %d) probe point found.\n", MAX_PROBES);
-
-        pp->probes[pp->found] = xstrdup(tmp);
-        pp->found++;
 }
 
 /* Find probe point from its line number */
@@ -512,7 +493,7 @@ static void find_probe_point_by_line(struct probe_finder *pf)
                          (int)i, lineno, (uintmax_t)addr);
                 pf->addr = addr;
 
-                show_probe_point(NULL, pf);
+                convert_probe_point(NULL, pf);
                 /* Continuing, because target line might be inlined. */
         }
 }
@@ -563,7 +544,7 @@ static void find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
         if (list_empty(&pf->lcache)) {
                 /* Matching lazy line pattern */
                 ret = find_lazy_match_lines(&pf->lcache, pf->fname,
-                                            pf->pp->lazy_line);
+                                            pf->pev->point.lazy_line);
                 if (ret <= 0)
                         die("No matched lines found in %s.", pf->fname);
         }
@@ -596,7 +577,7 @@ static void find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
                          (int)i, lineno, (unsigned long long)addr);
                 pf->addr = addr;
 
-                show_probe_point(sp_die, pf);
+                convert_probe_point(sp_die, pf);
                 /* Continuing, because target line might be inlined. */
         }
         /* TODO: deallocate lines, but how? */
@@ -605,7 +586,7 @@ static void find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
 static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 {
         struct probe_finder *pf = (struct probe_finder *)data;
-        struct probe_point *pp = pf->pp;
+        struct perf_probe_point *pp = &pf->pev->point;
 
         if (pp->lazy_line)
                 find_probe_point_lazy(in_die, pf);
@@ -616,7 +597,7 @@ static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
                 pr_debug("found inline addr: 0x%jx\n",
                          (uintmax_t)pf->addr);
 
-                show_probe_point(in_die, pf);
+                convert_probe_point(in_die, pf);
         }
 
         return DWARF_CB_OK;
@@ -626,7 +607,7 @@ static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
 static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
 {
         struct probe_finder *pf = (struct probe_finder *)data;
-        struct probe_point *pp = pf->pp;
+        struct perf_probe_point *pp = &pf->pev->point;
 
         /* Check tag and diename */
         if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
@@ -646,7 +627,7 @@ static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
                         pf->addr = die_get_entrypc(sp_die);
                         pf->addr += pp->offset;
                         /* TODO: Check the address in this function */
-                        show_probe_point(sp_die, pf);
+                        convert_probe_point(sp_die, pf);
                 }
         } else
                 /* Inlined function: search instances */
@@ -660,20 +641,25 @@ static void find_probe_point_by_func(struct probe_finder *pf)
         dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, pf, 0);
 }
 
-/* Find a probe point */
-int find_probe_point(int fd, struct probe_point *pp)
+/* Find kprobe_trace_events specified by perf_probe_event from debuginfo */
+int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
+                             struct kprobe_trace_event **tevs)
 {
-        struct probe_finder pf = {.pp = pp};
+        struct probe_finder pf = {.pev = pev};
+        struct perf_probe_point *pp = &pev->point;
         Dwarf_Off off, noff;
         size_t cuhl;
         Dwarf_Die *diep;
         Dwarf *dbg;
 
+        pf.tevs = xzalloc(sizeof(struct kprobe_trace_event) * MAX_PROBES);
+        *tevs = pf.tevs;
+        pf.ntevs = 0;
+
         dbg = dwarf_begin(fd, DWARF_C_READ);
         if (!dbg)
                 return -ENOENT;
 
-        pp->found = 0;
         off = 0;
         line_list__init(&pf.lcache);
         /* Loop on CUs (Compilation Unit) */
@@ -704,7 +690,7 @@ int find_probe_point(int fd, struct probe_point *pp)
         line_list__free(&pf.lcache);
         dwarf_end(dbg);
 
-        return pp->found;
+        return pf.ntevs;
 }
 
 /* Find line range from its line number */