From d3030191d3a6292408c5cf999ebcc1d10e00e9c2 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Tue, 16 Jan 2024 22:26:51 -0800 Subject: perf annotate-data: Handle array style accesses On x86, instructions for array access often looks like below. mov 0x1234(%rax,%rbx,8), %rcx Usually the first register holds the type information and the second one has the index. And the current code only looks up a variable for the first register. But it's possible to be in the other way around so it needs to check the second register if the first one failed. The stat changed like this. Annotate data type stats: total 294, ok 148 (50.3%), bad 146 (49.7%) ----------------------------------------------------------- 30 : no_sym 32 : no_mem_ops 66 : no_var 10 : no_typeinfo 8 : bad_offset Reviewed-by: Ian Rogers Cc: Stephane Eranian Cc: Masami Hiramatsu Link: https://lore.kernel.org/r/20240117062657.985479-4-namhyung@kernel.org Signed-off-by: Namhyung Kim --- tools/perf/util/annotate-data.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) (limited to 'tools/perf/util/annotate-data.c') diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c index f22b4f18271c..d1ceac7e2441 100644 --- a/tools/perf/util/annotate-data.c +++ b/tools/perf/util/annotate-data.c @@ -9,6 +9,7 @@ #include #include +#include "annotate.h" #include "annotate-data.h" #include "debuginfo.h" #include "debug.h" @@ -207,7 +208,8 @@ static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset) * It expects a pointer type for a memory access. * Convert to a real type it points to. */ - if (dwarf_tag(type_die) != DW_TAG_pointer_type || + if ((dwarf_tag(type_die) != DW_TAG_pointer_type && + dwarf_tag(type_die) != DW_TAG_array_type) || die_get_real_type(type_die, type_die) == NULL) { pr_debug("no pointer or no type\n"); ann_data_stat.no_typeinfo++; @@ -233,10 +235,11 @@ static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset) /* The result will be saved in @type_die */ static int find_data_type_die(struct debuginfo *di, u64 pc, - int reg, int offset, Dwarf_Die *type_die) + struct annotated_op_loc *loc, Dwarf_Die *type_die) { Dwarf_Die cu_die, var_die; Dwarf_Die *scopes = NULL; + int reg, offset; int ret = -1; int i, nr_scopes; @@ -250,6 +253,10 @@ static int find_data_type_die(struct debuginfo *di, u64 pc, /* Get a list of nested scopes - i.e. (inlined) functions and blocks. */ nr_scopes = die_get_scopes(&cu_die, pc, &scopes); + reg = loc->reg1; + offset = loc->offset; + +retry: /* Search from the inner-most scope to the outer */ for (i = nr_scopes - 1; i >= 0; i--) { /* Look up variables/parameters in this scope */ @@ -260,6 +267,12 @@ static int find_data_type_die(struct debuginfo *di, u64 pc, ret = check_variable(&var_die, type_die, offset); goto out; } + + if (loc->multi_regs && reg == loc->reg1 && loc->reg1 != loc->reg2) { + reg = loc->reg2; + goto retry; + } + if (ret < 0) ann_data_stat.no_var++; @@ -272,15 +285,14 @@ out: * find_data_type - Return a data type at the location * @ms: map and symbol at the location * @ip: instruction address of the memory access - * @reg: register that holds the base address - * @offset: offset from the base address + * @loc: instruction operand location * * This functions searches the debug information of the binary to get the data * type it accesses. The exact location is expressed by (ip, reg, offset). * It return %NULL if not found. */ struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip, - int reg, int offset) + struct annotated_op_loc *loc) { struct annotated_data_type *result = NULL; struct dso *dso = map__dso(ms->map); @@ -300,7 +312,7 @@ struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip, * a file address for DWARF processing. */ pc = map__rip_2objdump(ms->map, ip); - if (find_data_type_die(di, pc, reg, offset, &type_die) < 0) + if (find_data_type_die(di, pc, loc, &type_die) < 0) goto out; result = dso__findnew_data_type(dso, &type_die); -- cgit v1.2.3 From 83bfa06d08050d03d35004e8579df9718a614100 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Tue, 16 Jan 2024 22:26:53 -0800 Subject: perf annotate-data: Handle PC-relative addressing Extend find_data_type_die() to find data type from PC-relative address using die_find_variable_by_addr(). Users need to pass the address for the (global) variable. The offset for the variable should be updated after finding the type because the offset in the instruction is just to calcuate the address for the variable. So it changed to pass a pointer to offset and renamed it to 'poffset'. First it searches variables in the CU DIE as it's likely that the global variables are defined in the file level. And then it iterates the scope DIEs to find a local (static) variable. Reviewed-by: Ian Rogers Cc: Stephane Eranian Cc: Masami Hiramatsu Link: https://lore.kernel.org/r/20240117062657.985479-6-namhyung@kernel.org Signed-off-by: Namhyung Kim --- tools/perf/util/annotate-data.c | 56 ++++++++++++++++++++++++++++------------- 1 file changed, 38 insertions(+), 18 deletions(-) (limited to 'tools/perf/util/annotate-data.c') diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c index d1ceac7e2441..58c0fac42e9d 100644 --- a/tools/perf/util/annotate-data.c +++ b/tools/perf/util/annotate-data.c @@ -14,6 +14,7 @@ #include "debuginfo.h" #include "debug.h" #include "dso.h" +#include "dwarf-regs.h" #include "evsel.h" #include "evlist.h" #include "map.h" @@ -193,7 +194,8 @@ static bool find_cu_die(struct debuginfo *di, u64 pc, Dwarf_Die *cu_die) } /* The type info will be saved in @type_die */ -static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset) +static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset, + bool is_pointer) { Dwarf_Word size; @@ -205,15 +207,18 @@ static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset) } /* - * It expects a pointer type for a memory access. - * Convert to a real type it points to. + * Usually it expects a pointer type for a memory access. + * Convert to a real type it points to. But global variables + * are accessed directly without a pointer. */ - if ((dwarf_tag(type_die) != DW_TAG_pointer_type && - dwarf_tag(type_die) != DW_TAG_array_type) || - die_get_real_type(type_die, type_die) == NULL) { - pr_debug("no pointer or no type\n"); - ann_data_stat.no_typeinfo++; - return -1; + if (is_pointer) { + if ((dwarf_tag(type_die) != DW_TAG_pointer_type && + dwarf_tag(type_die) != DW_TAG_array_type) || + die_get_real_type(type_die, type_die) == NULL) { + pr_debug("no pointer or no type\n"); + ann_data_stat.no_typeinfo++; + return -1; + } } /* Get the size of the actual type */ @@ -234,7 +239,7 @@ static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset) } /* The result will be saved in @type_die */ -static int find_data_type_die(struct debuginfo *di, u64 pc, +static int find_data_type_die(struct debuginfo *di, u64 pc, u64 addr, struct annotated_op_loc *loc, Dwarf_Die *type_die) { Dwarf_Die cu_die, var_die; @@ -250,21 +255,36 @@ static int find_data_type_die(struct debuginfo *di, u64 pc, return -1; } - /* Get a list of nested scopes - i.e. (inlined) functions and blocks. */ - nr_scopes = die_get_scopes(&cu_die, pc, &scopes); - reg = loc->reg1; offset = loc->offset; + if (reg == DWARF_REG_PC && + die_find_variable_by_addr(&cu_die, pc, addr, &var_die, &offset)) { + ret = check_variable(&var_die, type_die, offset, + /*is_pointer=*/false); + goto out; + } + + /* Get a list of nested scopes - i.e. (inlined) functions and blocks. */ + nr_scopes = die_get_scopes(&cu_die, pc, &scopes); + retry: /* Search from the inner-most scope to the outer */ for (i = nr_scopes - 1; i >= 0; i--) { - /* Look up variables/parameters in this scope */ - if (!die_find_variable_by_reg(&scopes[i], pc, reg, &var_die)) - continue; + if (reg == DWARF_REG_PC) { + if (!die_find_variable_by_addr(&scopes[i], pc, addr, + &var_die, &offset)) + continue; + } else { + /* Look up variables/parameters in this scope */ + if (!die_find_variable_by_reg(&scopes[i], pc, reg, + &var_die)) + continue; + } /* Found a variable, see if it's correct */ - ret = check_variable(&var_die, type_die, offset); + ret = check_variable(&var_die, type_die, offset, + reg != DWARF_REG_PC); goto out; } @@ -312,7 +332,7 @@ struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip, * a file address for DWARF processing. */ pc = map__rip_2objdump(ms->map, ip); - if (find_data_type_die(di, pc, loc, &type_die) < 0) + if (find_data_type_die(di, pc, 0, loc, &type_die) < 0) goto out; result = dso__findnew_data_type(dso, &type_die); -- cgit v1.2.3 From 5f7cdde843dd21c7228d9ae47d985086ce165985 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Tue, 16 Jan 2024 22:26:54 -0800 Subject: perf annotate-data: Support global variables Global variables are accessed using PC-relative address so it needs to be handled separately. The PC-rel addressing is detected by using DWARF_REG_PC. On x86, %rip register would be used. The address can be calculated using the ip and offset in the instruction. But it should start from the next instruction so add calculate_pcrel_addr() to do it properly. But global variables defined in a different file would only have a declaration which doesn't include a location list. So it first tries to get the type info using the address, and then looks up the variable declarations using name. The name of global variables should be get from the symbol table. The declaration would have the type info. So extend find_var_type() to take both address and name for global variables. The stat is now looks like: Annotate data type stats: total 294, ok 153 (52.0%), bad 141 (48.0%) ----------------------------------------------------------- 30 : no_sym 32 : no_mem_ops 61 : no_var 10 : no_typeinfo 8 : bad_offset Reviewed-by: Ian Rogers Cc: Stephane Eranian Cc: Masami Hiramatsu Link: https://lore.kernel.org/r/20240117062657.985479-7-namhyung@kernel.org Signed-off-by: Namhyung Kim --- tools/perf/util/annotate-data.c | 38 ++++++++++++++++++++------- tools/perf/util/annotate-data.h | 6 +++-- tools/perf/util/annotate.c | 57 +++++++++++++++++++++++++++++++++++++++-- tools/perf/util/annotate.h | 4 +++ 4 files changed, 92 insertions(+), 13 deletions(-) (limited to 'tools/perf/util/annotate-data.c') diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c index 58c0fac42e9d..e375dd288f67 100644 --- a/tools/perf/util/annotate-data.c +++ b/tools/perf/util/annotate-data.c @@ -240,7 +240,8 @@ static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset, /* The result will be saved in @type_die */ static int find_data_type_die(struct debuginfo *di, u64 pc, u64 addr, - struct annotated_op_loc *loc, Dwarf_Die *type_die) + const char *var_name, struct annotated_op_loc *loc, + Dwarf_Die *type_die) { Dwarf_Die cu_die, var_die; Dwarf_Die *scopes = NULL; @@ -258,11 +259,21 @@ static int find_data_type_die(struct debuginfo *di, u64 pc, u64 addr, reg = loc->reg1; offset = loc->offset; - if (reg == DWARF_REG_PC && - die_find_variable_by_addr(&cu_die, pc, addr, &var_die, &offset)) { - ret = check_variable(&var_die, type_die, offset, - /*is_pointer=*/false); - goto out; + if (reg == DWARF_REG_PC) { + if (die_find_variable_by_addr(&cu_die, pc, addr, &var_die, &offset)) { + ret = check_variable(&var_die, type_die, offset, + /*is_pointer=*/false); + loc->offset = offset; + goto out; + } + + if (var_name && die_find_variable_at(&cu_die, var_name, pc, + &var_die)) { + ret = check_variable(&var_die, type_die, 0, + /*is_pointer=*/false); + /* loc->offset will be updated by the caller */ + goto out; + } } /* Get a list of nested scopes - i.e. (inlined) functions and blocks. */ @@ -285,6 +296,7 @@ retry: /* Found a variable, see if it's correct */ ret = check_variable(&var_die, type_die, offset, reg != DWARF_REG_PC); + loc->offset = offset; goto out; } @@ -306,13 +318,21 @@ out: * @ms: map and symbol at the location * @ip: instruction address of the memory access * @loc: instruction operand location + * @addr: data address of the memory access + * @var_name: global variable name * * This functions searches the debug information of the binary to get the data - * type it accesses. The exact location is expressed by (ip, reg, offset). + * type it accesses. The exact location is expressed by (@ip, reg, offset) + * for pointer variables or (@ip, @addr) for global variables. Note that global + * variables might update the @loc->offset after finding the start of the variable. + * If it cannot find a global variable by address, it tried to fine a declaration + * of the variable using @var_name. In that case, @loc->offset won't be updated. + * * It return %NULL if not found. */ struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip, - struct annotated_op_loc *loc) + struct annotated_op_loc *loc, u64 addr, + const char *var_name) { struct annotated_data_type *result = NULL; struct dso *dso = map__dso(ms->map); @@ -332,7 +352,7 @@ struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip, * a file address for DWARF processing. */ pc = map__rip_2objdump(ms->map, ip); - if (find_data_type_die(di, pc, 0, loc, &type_die) < 0) + if (find_data_type_die(di, pc, addr, var_name, loc, &type_die) < 0) goto out; result = dso__findnew_data_type(dso, &type_die); diff --git a/tools/perf/util/annotate-data.h b/tools/perf/util/annotate-data.h index 214c625e7bc9..1b0db8e8c40e 100644 --- a/tools/perf/util/annotate-data.h +++ b/tools/perf/util/annotate-data.h @@ -107,7 +107,8 @@ extern struct annotated_data_stat ann_data_stat; /* Returns data type at the location (ip, reg, offset) */ struct annotated_data_type *find_data_type(struct map_symbol *ms, u64 ip, - struct annotated_op_loc *loc); + struct annotated_op_loc *loc, u64 addr, + const char *var_name); /* Update type access histogram at the given offset */ int annotated_data_type__update_samples(struct annotated_data_type *adt, @@ -121,7 +122,8 @@ void annotated_data_type__tree_delete(struct rb_root *root); static inline struct annotated_data_type * find_data_type(struct map_symbol *ms __maybe_unused, u64 ip __maybe_unused, - struct annotated_op_loc *loc __maybe_unused) + struct annotated_op_loc *loc __maybe_unused, + u64 addr __maybe_unused, const char *var_name __maybe_unused) { return NULL; } diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c index 655bd9443f5e..107b264fa41e 100644 --- a/tools/perf/util/annotate.c +++ b/tools/perf/util/annotate.c @@ -37,6 +37,7 @@ #include "util/sharded_mutex.h" #include "arch/common.h" #include "namespaces.h" +#include "thread.h" #include #include #include @@ -3744,6 +3745,30 @@ static bool is_stack_operation(struct arch *arch, struct disasm_line *dl) return false; } +u64 annotate_calc_pcrel(struct map_symbol *ms, u64 ip, int offset, + struct disasm_line *dl) +{ + struct annotation *notes; + struct disasm_line *next; + u64 addr; + + notes = symbol__annotation(ms->sym); + /* + * PC-relative addressing starts from the next instruction address + * But the IP is for the current instruction. Since disasm_line + * doesn't have the instruction size, calculate it using the next + * disasm_line. If it's the last one, we can use symbol's end + * address directly. + */ + if (&dl->al.node == notes->src->source.prev) + addr = ms->sym->end + offset; + else { + next = list_next_entry(dl, al.node); + addr = ip + (next->al.offset - dl->al.offset) + offset; + } + return map__rip_2objdump(ms->map, addr); +} + /** * hist_entry__get_data_type - find data type for given hist entry * @he: hist entry @@ -3763,7 +3788,9 @@ struct annotated_data_type *hist_entry__get_data_type(struct hist_entry *he) struct annotated_op_loc *op_loc; struct annotated_data_type *mem_type; struct annotated_item_stat *istat; - u64 ip = he->ip; + u64 ip = he->ip, addr = 0; + const char *var_name = NULL; + int var_offset; int i; ann_data_stat.total++; @@ -3822,12 +3849,38 @@ retry: /* Recalculate IP because of LOCK prefix or insn fusion */ ip = ms->sym->start + dl->al.offset; - mem_type = find_data_type(ms, ip, op_loc); + var_offset = op_loc->offset; + + /* PC-relative addressing */ + if (op_loc->reg1 == DWARF_REG_PC) { + struct addr_location al; + struct symbol *var; + u64 map_addr; + + addr = annotate_calc_pcrel(ms, ip, op_loc->offset, dl); + /* Kernel symbols might be relocated */ + map_addr = addr + map__reloc(ms->map); + + addr_location__init(&al); + var = thread__find_symbol_fb(he->thread, he->cpumode, + map_addr, &al); + if (var) { + var_name = var->name; + /* Calculate type offset from the start of variable */ + var_offset = map_addr - map__unmap_ip(al.map, var->start); + } + addr_location__exit(&al); + } + + mem_type = find_data_type(ms, ip, op_loc, addr, var_name); if (mem_type) istat->good++; else istat->bad++; + if (mem_type && var_name) + op_loc->offset = var_offset; + if (symbol_conf.annotate_data_sample) { annotated_data_type__update_samples(mem_type, evsel, op_loc->offset, diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h index d0ff677b460c..94435607c958 100644 --- a/tools/perf/util/annotate.h +++ b/tools/perf/util/annotate.h @@ -491,4 +491,8 @@ struct annotated_item_stat { }; extern struct list_head ann_insn_stat; +/* Calculate PC-relative address */ +u64 annotate_calc_pcrel(struct map_symbol *ms, u64 ip, int offset, + struct disasm_line *dl); + #endif /* __PERF_ANNOTATE_H */ -- cgit v1.2.3 From bc10db8eb8955fbcaf29f75c91147e4e724b740d Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Tue, 16 Jan 2024 22:26:56 -0800 Subject: perf annotate-data: Support stack variables Local variables are allocated in the stack and the location list should look like base register(s) and an offset. Extend the die_find_variable_by_reg() to handle the following expressions * DW_OP_breg{0..31} * DW_OP_bregx * DW_OP_fbreg Ususally DWARF subprogram entries have frame base information and use it to locate stack variable like below: <2><43d1575>: Abbrev Number: 62 (DW_TAG_variable) <43d1576> DW_AT_location : 2 byte block: 91 7c (DW_OP_fbreg: -4) <--- here <43d1579> DW_AT_name : (indirect string, offset: 0x2c00c9): i <43d157d> DW_AT_decl_file : 1 <43d157e> DW_AT_decl_line : 78 <43d157f> DW_AT_type : <0x43d19d7> I found some differences on saving the frame base between gcc and clang. The gcc uses the CFA to get the base so it needs to check the current frame's CFI info. In this case, stack offset needs to be adjusted from the start of the CFA. <1><1bb8d>: Abbrev Number: 102 (DW_TAG_subprogram) <1bb8e> DW_AT_name : (indirect string, offset: 0x74d41): kernel_init <1bb92> DW_AT_decl_file : 2 <1bb92> DW_AT_decl_line : 1440 <1bb94> DW_AT_decl_column : 18 <1bb95> DW_AT_prototyped : 1 <1bb95> DW_AT_type : <0xcc> <1bb99> DW_AT_low_pc : 0xffffffff81bab9e0 <1bba1> DW_AT_high_pc : 0x1b2 <1bba9> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa) <------ here <1bbab> DW_AT_call_all_calls: 1 <1bbab> DW_AT_sibling : <0x1bf5a> While clang sets it to a register directly and it can check the register and offset in the instruction directly. <1><43d1542>: Abbrev Number: 60 (DW_TAG_subprogram) <43d1543> DW_AT_low_pc : 0xffffffff816a7c60 <43d154b> DW_AT_high_pc : 0x98 <43d154f> DW_AT_frame_base : 1 byte block: 56 (DW_OP_reg6 (rbp)) <---------- here <43d1551> DW_AT_GNU_all_call_sites: 1 <43d1551> DW_AT_name : (indirect string, offset: 0x3bce91): foo <43d1555> DW_AT_decl_file : 1 <43d1556> DW_AT_decl_line : 75 <43d1557> DW_AT_prototyped : 1 <43d1557> DW_AT_type : <0x43c7332> <43d155b> DW_AT_external : 1 Also it needs to update the offset after finding the type like global variables since the offset was from the frame base. Factor out match_var_offset() to check global and local variables in the same way. The type stats are improved too: Annotate data type stats: total 294, ok 160 (54.4%), bad 134 (45.6%) ----------------------------------------------------------- 30 : no_sym 32 : no_mem_ops 51 : no_var 14 : no_typeinfo 7 : bad_offset Reviewed-by: Ian Rogers Cc: Stephane Eranian Cc: Masami Hiramatsu Link: https://lore.kernel.org/r/20240117062657.985479-9-namhyung@kernel.org Signed-off-by: Namhyung Kim --- tools/perf/util/annotate-data.c | 35 ++++++++++++++++-- tools/perf/util/dwarf-aux.c | 79 ++++++++++++++++++++++++++++++----------- tools/perf/util/dwarf-aux.h | 3 ++ 3 files changed, 93 insertions(+), 24 deletions(-) (limited to 'tools/perf/util/annotate-data.c') diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c index e375dd288f67..30c4d19fcf11 100644 --- a/tools/perf/util/annotate-data.c +++ b/tools/perf/util/annotate-data.c @@ -209,7 +209,7 @@ static int check_variable(Dwarf_Die *var_die, Dwarf_Die *type_die, int offset, /* * Usually it expects a pointer type for a memory access. * Convert to a real type it points to. But global variables - * are accessed directly without a pointer. + * and local variables are accessed directly without a pointer. */ if (is_pointer) { if ((dwarf_tag(type_die) != DW_TAG_pointer_type && @@ -248,6 +248,9 @@ static int find_data_type_die(struct debuginfo *di, u64 pc, u64 addr, int reg, offset; int ret = -1; int i, nr_scopes; + int fbreg = -1; + bool is_fbreg = false; + int fb_offset = 0; /* Get a compile_unit for this address */ if (!find_cu_die(di, pc, &cu_die)) { @@ -279,7 +282,33 @@ static int find_data_type_die(struct debuginfo *di, u64 pc, u64 addr, /* Get a list of nested scopes - i.e. (inlined) functions and blocks. */ nr_scopes = die_get_scopes(&cu_die, pc, &scopes); + if (reg != DWARF_REG_PC && dwarf_hasattr(&scopes[0], DW_AT_frame_base)) { + Dwarf_Attribute attr; + Dwarf_Block block; + + /* Check if the 'reg' is assigned as frame base register */ + if (dwarf_attr(&scopes[0], DW_AT_frame_base, &attr) != NULL && + dwarf_formblock(&attr, &block) == 0 && block.length == 1) { + switch (*block.data) { + case DW_OP_reg0 ... DW_OP_reg31: + fbreg = *block.data - DW_OP_reg0; + break; + case DW_OP_call_frame_cfa: + if (die_get_cfa(di->dbg, pc, &fbreg, + &fb_offset) < 0) + fbreg = -1; + break; + default: + break; + } + } + } + retry: + is_fbreg = (reg == fbreg); + if (is_fbreg) + offset = loc->offset - fb_offset; + /* Search from the inner-most scope to the outer */ for (i = nr_scopes - 1; i >= 0; i--) { if (reg == DWARF_REG_PC) { @@ -289,13 +318,13 @@ retry: } else { /* Look up variables/parameters in this scope */ if (!die_find_variable_by_reg(&scopes[i], pc, reg, - &var_die)) + &offset, is_fbreg, &var_die)) continue; } /* Found a variable, see if it's correct */ ret = check_variable(&var_die, type_die, offset, - reg != DWARF_REG_PC); + reg != DWARF_REG_PC && !is_fbreg); loc->offset = offset; goto out; } diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 3d42a8613869..7caf52fdc255 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -1272,11 +1272,39 @@ struct find_var_data { unsigned reg; /* Access offset, set for global data */ int offset; + /* True if the current register is the frame base */ + bool is_fbreg; }; /* Max number of registers DW_OP_regN supports */ #define DWARF_OP_DIRECT_REGS 32 +static bool match_var_offset(Dwarf_Die *die_mem, struct find_var_data *data, + u64 addr_offset, u64 addr_type) +{ + Dwarf_Die type_die; + Dwarf_Word size; + + if (addr_offset == addr_type) { + /* Update offset relative to the start of the variable */ + data->offset = 0; + return true; + } + + if (die_get_real_type(die_mem, &type_die) == NULL) + return false; + + if (dwarf_aggregate_size(&type_die, &size) < 0) + return false; + + if (addr_offset >= addr_type + size) + return false; + + /* Update offset relative to the start of the variable */ + data->offset = addr_offset - addr_type; + return true; +} + /* Only checks direct child DIEs in the given scope. */ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) { @@ -1301,14 +1329,30 @@ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) if (start > data->pc) break; + /* Local variables accessed using frame base register */ + if (data->is_fbreg && ops->atom == DW_OP_fbreg && + data->offset >= (int)ops->number && + match_var_offset(die_mem, data, data->offset, ops->number)) + return DIE_FIND_CB_END; + /* Only match with a simple case */ if (data->reg < DWARF_OP_DIRECT_REGS) { if (ops->atom == (DW_OP_reg0 + data->reg) && nops == 1) return DIE_FIND_CB_END; + + /* Local variables accessed by a register + offset */ + if (ops->atom == (DW_OP_breg0 + data->reg) && + match_var_offset(die_mem, data, data->offset, ops->number)) + return DIE_FIND_CB_END; } else { if (ops->atom == DW_OP_regx && ops->number == data->reg && nops == 1) return DIE_FIND_CB_END; + + /* Local variables accessed by a register + offset */ + if (ops->atom == DW_OP_bregx && data->reg == ops->number && + match_var_offset(die_mem, data, data->offset, ops->number2)) + return DIE_FIND_CB_END; } } return DIE_FIND_CB_SIBLING; @@ -1319,18 +1363,29 @@ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) * @sc_die: a scope DIE * @pc: the program address to find * @reg: the register number to find + * @poffset: pointer to offset, will be updated for fbreg case + * @is_fbreg: boolean value if the current register is the frame base * @die_mem: a buffer to save the resulting DIE * - * Find the variable DIE accessed by the given register. + * Find the variable DIE accessed by the given register. It'll update the @offset + * 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 *die_mem) { struct find_var_data data = { .pc = pc, .reg = reg, + .offset = *poffset, + .is_fbreg = is_fbreg, }; - return die_find_child(sc_die, __die_find_var_reg_cb, &data, die_mem); + Dwarf_Die *result; + + result = die_find_child(sc_die, __die_find_var_reg_cb, &data, die_mem); + if (result) + *poffset = data.offset; + return result; } /* Only checks direct child DIEs in the given scope */ @@ -1341,8 +1396,6 @@ static int __die_find_var_addr_cb(Dwarf_Die *die_mem, void *arg) ptrdiff_t off = 0; Dwarf_Attribute attr; Dwarf_Addr base, start, end; - Dwarf_Word size; - Dwarf_Die type_die; Dwarf_Op *ops; size_t nops; @@ -1359,24 +1412,8 @@ static int __die_find_var_addr_cb(Dwarf_Die *die_mem, void *arg) if (data->addr < ops->number) continue; - if (data->addr == ops->number) { - /* Update offset relative to the start of the variable */ - data->offset = 0; + if (match_var_offset(die_mem, data, data->addr, ops->number)) return DIE_FIND_CB_END; - } - - if (die_get_real_type(die_mem, &type_die) == NULL) - continue; - - if (dwarf_aggregate_size(&type_die, &size) < 0) - continue; - - if (data->addr >= ops->number + size) - continue; - - /* Update offset relative to the start of the variable */ - data->offset = data->addr - ops->number; - return DIE_FIND_CB_END; } return DIE_FIND_CB_SIBLING; } diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h index f209f9162908..85dd527ae1f7 100644 --- a/tools/perf/util/dwarf-aux.h +++ b/tools/perf/util/dwarf-aux.h @@ -142,6 +142,7 @@ 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 *die_mem); /* Find a (global) variable located in the 'addr' */ @@ -161,6 +162,8 @@ static inline int die_get_var_range(Dwarf_Die *sp_die __maybe_unused, static inline Dwarf_Die *die_find_variable_by_reg(Dwarf_Die *sc_die __maybe_unused, Dwarf_Addr pc __maybe_unused, int reg __maybe_unused, + int *poffset __maybe_unused, + bool is_fbreg __maybe_unused, Dwarf_Die *die_mem __maybe_unused) { return NULL; -- cgit v1.2.3