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The additional check_variable call is redundant, and its need_pointer logic is only a heuristic. Since DWARF encodes accurate type information, which match_var_offset verifies, skipping check_variable improves both coverage and accuracy. Return type from die_find_variable_by_reg via a new `type` field in find_var_data. Signed-off-by: Zecheng Li --- tools/perf/util/annotate-data.c | 8 +++++--- tools/perf/util/dwarf-aux.c | 18 +++++++++++------- tools/perf/util/dwarf-aux.h | 2 +- 3 files changed, 17 insertions(+), 11 deletions(-) diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c index e183c6104d59..4b08331b9dd3 100644 --- a/tools/perf/util/annotate-data.c +++ b/tools/perf/util/annotate-data.c @@ -1603,19 +1603,21 @@ static int find_data_type_die(struct data_loc_info *dloc, Dwarf_Die *type_die) if (!die_find_variable_by_addr(&scopes[i], dloc->var_addr, &var_die, &type_offset)) continue; + /* Found a variable, see if it's correct */ + result = check_variable(dloc, &var_die, &mem_die, reg, + type_offset, is_fbreg); } else { /* Look up variables/parameters in this scope */ if (!die_find_variable_by_reg(&scopes[i], pc, reg, - &type_offset, is_fbreg, &var_die)) + &mem_die, &type_offset, is_fbreg, &var_die)) continue; + result = PERF_TMR_OK; } pr_debug_dtp("found \"%s\" (die: %#lx) in scope=%d/%d (die: %#lx) ", dwarf_diename(&var_die), (long)dwarf_dieoffset(&var_die), i+1, nr_scopes, (long)dwarf_dieoffset(&scopes[i])); - /* Found a variable, see if it's correct */ - result = check_variable(dloc, &var_die, &mem_die, reg, type_offset, is_fbreg); if (result == PERF_TMR_OK) { if (reg == DWARF_REG_PC) { pr_debug_dtp("addr=%#"PRIx64" type_offset=%#x\n", diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 9267af204c7d..b57cdc8860f0 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -1378,6 +1378,8 @@ struct find_var_data { Dwarf_Addr addr; /* Target register */ unsigned reg; + /* Access data type */ + Dwarf_Die type; /* Access offset, set for global data */ int offset; /* True if the current register is the frame base */ @@ -1390,7 +1392,6 @@ struct find_var_data { static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data, s64 addr_offset, s64 addr_type, bool is_pointer) { - Dwarf_Die type_die; Dwarf_Word size; s64 offset = addr_offset - addr_type; @@ -1403,16 +1404,16 @@ static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data, if (offset < 0) return false; - if (die_get_real_type(die_mem, &type_die) == NULL) + if (die_get_real_type(die_mem, &data->type) == NULL) return false; - if (is_pointer && dwarf_tag(&type_die) == DW_TAG_pointer_type) { + if (is_pointer && dwarf_tag(&data->type) == DW_TAG_pointer_type) { /* Get the target type of the pointer */ - if (die_get_real_type(&type_die, &type_die) == NULL) + if (die_get_real_type(&data->type, &data->type) == NULL) return false; } - if (dwarf_aggregate_size(&type_die, &size) < 0) + if (dwarf_aggregate_size(&data->type, &size) < 0) return false; if ((u64)offset >= size) @@ -1529,7 +1530,7 @@ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) * when the variable is in the stack. */ Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die, Dwarf_Addr pc, int reg, - int *poffset, bool is_fbreg, + Dwarf_Die *type_die, int *poffset, bool is_fbreg, Dwarf_Die *die_mem) { struct find_var_data data = { @@ -1541,8 +1542,11 @@ Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die, Dwarf_Addr pc, int reg, Dwarf_Die *result; result = die_find_child(sc_die, __die_find_var_reg_cb, &data, die_mem); - if (result) + if (result) { *poffset = data.offset; + *type_die = data.type; + } + return result; } diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h index cd481ec9c5a1..b3ee5df0b6be 100644 --- a/tools/perf/util/dwarf-aux.h +++ b/tools/perf/util/dwarf-aux.h @@ -163,7 +163,7 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf); /* Find a variable saved in the 'reg' at given address */ Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die, Dwarf_Addr pc, int reg, - int *poffset, bool is_fbreg, + Dwarf_Die *type_die, int *poffset, bool is_fbreg, Dwarf_Die *die_mem); /* Find a (global) variable located in the 'addr' */ -- 2.51.0.788.g6d19910ace-goog