Commit 6243b9dc authored by Ravi Bangoria's avatar Ravi Bangoria Committed by Arnaldo Carvalho de Melo

perf probe: Move dwarf specific functions to dwarf-aux.c

Move generic dwarf related functions from util/probe-finder.c to
util/dwarf-aux.c. Functions name and their prototype are also changed
accordingly. No functionality changes.
Suggested-and-Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1472546377-25612-1-git-send-email-ravi.bangoria@linux.vnet.ibm.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e47392bf
......@@ -1085,3 +1085,182 @@ int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
return -ENOTSUP;
}
#endif
/*
* die_has_loclist - Check if DW_AT_location of @vr_die is a location list
* @vr_die: a variable DIE
*/
static bool die_has_loclist(Dwarf_Die *vr_die)
{
Dwarf_Attribute loc;
int tag = dwarf_tag(vr_die);
if (tag != DW_TAG_formal_parameter &&
tag != DW_TAG_variable)
return false;
return (dwarf_attr_integrate(vr_die, DW_AT_location, &loc) &&
dwarf_whatform(&loc) == DW_FORM_sec_offset);
}
/*
* die_is_optimized_target - Check if target program is compiled with
* optimization
* @cu_die: a CU DIE
*
* For any object in given CU whose DW_AT_location is a location list,
* target program is compiled with optimization. This is applicable to
* clang as well.
*/
bool die_is_optimized_target(Dwarf_Die *cu_die)
{
Dwarf_Die tmp_die;
if (die_has_loclist(cu_die))
return true;
if (!dwarf_child(cu_die, &tmp_die) &&
die_is_optimized_target(&tmp_die))
return true;
if (!dwarf_siblingof(cu_die, &tmp_die) &&
die_is_optimized_target(&tmp_die))
return true;
return false;
}
/*
* die_search_idx - Search index of given line address
* @lines: Line records of single CU
* @nr_lines: Number of @lines
* @addr: address we are looking for
* @idx: index to be set by this function (return value)
*
* Search for @addr by looping over every lines of CU. If address
* matches, set index of that line in @idx. Note that single source
* line can have multiple line records. i.e. single source line can
* have multiple index.
*/
static bool die_search_idx(Dwarf_Lines *lines, unsigned long nr_lines,
Dwarf_Addr addr, unsigned long *idx)
{
unsigned long i;
Dwarf_Addr tmp;
for (i = 0; i < nr_lines; i++) {
if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &tmp))
return false;
if (tmp == addr) {
*idx = i;
return true;
}
}
return false;
}
/*
* die_get_postprologue_addr - Search next address after function prologue
* @entrypc_idx: entrypc index
* @lines: Line records of single CU
* @nr_lines: Number of @lines
* @hignpc: high PC address of function
* @postprologue_addr: Next address after function prologue (return value)
*
* Look for prologue-end marker. If there is no explicit marker, return
* address of next line record or next source line.
*/
static bool die_get_postprologue_addr(unsigned long entrypc_idx,
Dwarf_Lines *lines,
unsigned long nr_lines,
Dwarf_Addr highpc,
Dwarf_Addr *postprologue_addr)
{
unsigned long i;
int entrypc_lno, lno;
Dwarf_Line *line;
Dwarf_Addr addr;
bool p_end;
/* entrypc_lno is actual source line number */
line = dwarf_onesrcline(lines, entrypc_idx);
if (dwarf_lineno(line, &entrypc_lno))
return false;
for (i = entrypc_idx; i < nr_lines; i++) {
line = dwarf_onesrcline(lines, i);
if (dwarf_lineaddr(line, &addr) ||
dwarf_lineno(line, &lno) ||
dwarf_lineprologueend(line, &p_end))
return false;
/* highpc is exclusive. [entrypc,highpc) */
if (addr >= highpc)
break;
/* clang supports prologue-end marker */
if (p_end)
break;
/* Actual next line in source */
if (lno != entrypc_lno)
break;
/*
* Single source line can have multiple line records.
* For Example,
* void foo() { printf("hello\n"); }
* contains two line records. One points to declaration and
* other points to printf() line. Variable 'lno' won't get
* incremented in this case but 'i' will.
*/
if (i != entrypc_idx)
break;
}
dwarf_lineaddr(line, postprologue_addr);
if (*postprologue_addr >= highpc)
dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
postprologue_addr);
return true;
}
/*
* die_skip_prologue - Use next address after prologue as probe location
* @sp_die: a subprogram DIE
* @cu_die: a CU DIE
* @entrypc: entrypc of the function
*
* Function prologue prepares stack and registers before executing function
* logic. When target program is compiled without optimization, function
* parameter information is only valid after prologue. When we probe entrypc
* of the function, and try to record function parameter, it contains
* garbage value.
*/
void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
Dwarf_Addr *entrypc)
{
size_t nr_lines = 0;
unsigned long entrypc_idx = 0;
Dwarf_Lines *lines = NULL;
Dwarf_Addr postprologue_addr;
Dwarf_Addr highpc;
if (dwarf_highpc(sp_die, &highpc))
return;
if (dwarf_getsrclines(cu_die, &lines, &nr_lines))
return;
if (!die_search_idx(lines, nr_lines, *entrypc, &entrypc_idx))
return;
if (!die_get_postprologue_addr(entrypc_idx, lines, nr_lines,
highpc, &postprologue_addr))
return;
*entrypc = postprologue_addr;
}
......@@ -125,4 +125,12 @@ int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf);
/* Get the name and type of given variable DIE, stored as "type\tname" */
int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf);
int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf);
/* Check if target program is compiled with optimization */
bool die_is_optimized_target(Dwarf_Die *cu_die);
/* Use next address after prologue as probe location */
void die_skip_prologue(Dwarf_Die *sp_die, Dwarf_Die *cu_die,
Dwarf_Addr *entrypc);
#endif
......@@ -907,138 +907,6 @@ static int find_probe_point_lazy(Dwarf_Die *sp_die, struct probe_finder *pf)
return die_walk_lines(sp_die, probe_point_lazy_walker, pf);
}
static bool var_has_loclist(Dwarf_Die *cu_die)
{
Dwarf_Attribute loc;
int tag = dwarf_tag(cu_die);
if (tag != DW_TAG_formal_parameter &&
tag != DW_TAG_variable)
return false;
return (dwarf_attr_integrate(cu_die, DW_AT_location, &loc) &&
dwarf_whatform(&loc) == DW_FORM_sec_offset);
}
/*
* For any object in given CU whose DW_AT_location is a location list,
* target program is compiled with optimization.
*/
static bool optimized_target(Dwarf_Die *cu_die)
{
Dwarf_Die tmp_die;
if (var_has_loclist(cu_die))
return true;
if (!dwarf_child(cu_die, &tmp_die) && optimized_target(&tmp_die))
return true;
if (!dwarf_siblingof(cu_die, &tmp_die) && optimized_target(&tmp_die))
return true;
return false;
}
static bool get_entrypc_idx(Dwarf_Lines *lines, unsigned long nr_lines,
Dwarf_Addr pf_addr, unsigned long *entrypc_idx)
{
unsigned long i;
Dwarf_Addr addr;
for (i = 0; i < nr_lines; i++) {
if (dwarf_lineaddr(dwarf_onesrcline(lines, i), &addr))
return false;
if (addr == pf_addr) {
*entrypc_idx = i;
return true;
}
}
return false;
}
static bool get_postprologue_addr(unsigned long entrypc_idx,
Dwarf_Lines *lines,
unsigned long nr_lines,
Dwarf_Addr highpc,
Dwarf_Addr *postprologue_addr)
{
unsigned long i;
int entrypc_lno, lno;
Dwarf_Line *line;
Dwarf_Addr addr;
bool p_end;
/* entrypc_lno is actual source line number */
line = dwarf_onesrcline(lines, entrypc_idx);
if (dwarf_lineno(line, &entrypc_lno))
return false;
for (i = entrypc_idx; i < nr_lines; i++) {
line = dwarf_onesrcline(lines, i);
if (dwarf_lineaddr(line, &addr) ||
dwarf_lineno(line, &lno) ||
dwarf_lineprologueend(line, &p_end))
return false;
/* highpc is exclusive. [entrypc,highpc) */
if (addr >= highpc)
break;
/* clang supports prologue-end marker */
if (p_end)
break;
/* Actual next line in source */
if (lno != entrypc_lno)
break;
/*
* Single source line can have multiple line records.
* For Example,
* void foo() { printf("hello\n"); }
* contains two line records. One points to declaration and
* other points to printf() line. Variable 'lno' won't get
* incremented in this case but 'i' will.
*/
if (i != entrypc_idx)
break;
}
dwarf_lineaddr(line, postprologue_addr);
if (*postprologue_addr >= highpc)
dwarf_lineaddr(dwarf_onesrcline(lines, i - 1),
postprologue_addr);
return true;
}
static void __skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
{
size_t nr_lines = 0;
unsigned long entrypc_idx = 0;
Dwarf_Lines *lines = NULL;
Dwarf_Addr postprologue_addr;
Dwarf_Addr highpc;
if (dwarf_highpc(sp_die, &highpc))
return;
if (dwarf_getsrclines(&pf->cu_die, &lines, &nr_lines))
return;
if (!get_entrypc_idx(lines, nr_lines, pf->addr, &entrypc_idx))
return;
if (!get_postprologue_addr(entrypc_idx, lines, nr_lines,
highpc, &postprologue_addr))
return;
pf->addr = postprologue_addr;
}
static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
{
struct perf_probe_point *pp = &pf->pev->point;
......@@ -1048,7 +916,7 @@ static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
return;
/* Compiled with optimization? */
if (optimized_target(&pf->cu_die))
if (die_is_optimized_target(&pf->cu_die))
return;
/* Don't know entrypc? */
......@@ -1068,7 +936,7 @@ static void skip_prologue(Dwarf_Die *sp_die, struct probe_finder *pf)
"Probe on address 0x%" PRIx64 " to force probing at the function entry.\n\n",
pf->addr);
__skip_prologue(sp_die, pf);
die_skip_prologue(sp_die, &pf->cu_die, &pf->addr);
}
static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
......
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