diff options
Diffstat (limited to 'tools/perf/util/dwarf-aux.c')
| -rw-r--r-- | tools/perf/util/dwarf-aux.c | 511 |
1 files changed, 475 insertions, 36 deletions
diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 7aa5fee0da19..559c953ca172 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -9,6 +9,7 @@ #include <stdlib.h> #include "debug.h" #include "dwarf-aux.h" +#include "dwarf-regs.h" #include "strbuf.h" #include "string2.h" @@ -266,7 +267,7 @@ Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem) } /* Get a type die, but skip qualifiers */ -static Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem) +Dwarf_Die *__die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem) { int tag; @@ -696,6 +697,49 @@ Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr, return die_mem; } +static int __die_find_func_rettype_cb(Dwarf_Die *die_mem, void *data) +{ + const char *func_name; + + if (dwarf_tag(die_mem) != DW_TAG_subprogram) + return DIE_FIND_CB_SIBLING; + + func_name = dwarf_diename(die_mem); + if (func_name && !strcmp(func_name, data)) + return DIE_FIND_CB_END; + + return DIE_FIND_CB_SIBLING; +} + +/** + * die_find_func_rettype - Search a return type of function + * @cu_die: a CU DIE + * @name: target function name + * @die_mem: a buffer for result DIE + * + * Search a non-inlined function which matches to @name and stores the + * return type of the function to @die_mem and returns it if found. + * Returns NULL if failed. Note that it doesn't needs to find a + * definition of the function, so it doesn't match with address. + * Most likely, it can find a declaration at the top level. Thus the + * callback function continues to sibling entries only. + */ +Dwarf_Die *die_find_func_rettype(Dwarf_Die *cu_die, const char *name, + Dwarf_Die *die_mem) +{ + Dwarf_Die tmp_die; + + cu_die = die_find_child(cu_die, __die_find_func_rettype_cb, + (void *)name, &tmp_die); + if (!cu_die) + return NULL; + + if (die_get_real_type(&tmp_die, die_mem) == NULL) + return NULL; + + return die_mem; +} + struct __instance_walk_param { void *addr; int (*callback)(Dwarf_Die *, void *); @@ -1066,8 +1110,10 @@ int die_get_typename_from_type(Dwarf_Die *type_die, struct strbuf *buf) const char *tmp = ""; tag = dwarf_tag(type_die); - if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type) + if (tag == DW_TAG_pointer_type) tmp = "*"; + else if (tag == DW_TAG_array_type) + tmp = "[]"; else if (tag == DW_TAG_subroutine_type) { /* Function pointer */ return strbuf_add(buf, "(function_type)", 15); @@ -1136,7 +1182,69 @@ int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf) return ret < 0 ? ret : strbuf_addf(buf, "\t%s", dwarf_diename(vr_die)); } -#ifdef HAVE_DWARF_GETLOCATIONS_SUPPORT +static int reg_from_dwarf_op(Dwarf_Op *op) +{ + switch (op->atom) { + case DW_OP_reg0 ... DW_OP_reg31: + return op->atom - DW_OP_reg0; + case DW_OP_breg0 ... DW_OP_breg31: + return op->atom - DW_OP_breg0; + case DW_OP_regx: + case DW_OP_bregx: + return op->number; + case DW_OP_fbreg: + return DWARF_REG_FB; + default: + break; + } + return -1; +} + +static int offset_from_dwarf_op(Dwarf_Op *op) +{ + switch (op->atom) { + case DW_OP_reg0 ... DW_OP_reg31: + case DW_OP_regx: + return 0; + case DW_OP_breg0 ... DW_OP_breg31: + case DW_OP_fbreg: + return op->number; + case DW_OP_bregx: + return op->number2; + default: + break; + } + return -1; +} + +static bool check_allowed_ops(Dwarf_Op *ops, size_t nops) +{ + /* The first op is checked separately */ + ops++; + nops--; + + /* + * It needs to make sure if the location expression matches to the given + * register and offset exactly. Thus it rejects any complex expressions + * and only allows a few of selected operators that doesn't change the + * location. + */ + while (nops) { + switch (ops->atom) { + case DW_OP_stack_value: + case DW_OP_deref_size: + case DW_OP_deref: + case DW_OP_piece: + break; + default: + return false; + } + ops++; + nops--; + } + return true; +} + /** * die_get_var_innermost_scope - Get innermost scope range of given variable DIE * @sp_die: a subprogram DIE @@ -1272,11 +1380,48 @@ 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, bool is_pointer) +{ + 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 (addr_offset < addr_type) + return false; + + if (die_get_real_type(die_mem, &type_die) == NULL) + return false; + + if (is_pointer && dwarf_tag(&type_die) == DW_TAG_pointer_type) { + /* Get the target type of the pointer */ + if (die_get_real_type(&type_die, &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) { @@ -1296,18 +1441,46 @@ static int __die_find_var_reg_cb(Dwarf_Die *die_mem, void *arg) while ((off = dwarf_getlocations(&attr, off, &base, &start, &end, &ops, &nops)) > 0) { /* Assuming the location list is sorted by address */ - if (end < data->pc) + if (end <= data->pc) continue; if (start > data->pc) break; + /* Local variables accessed using frame base register */ + if (data->is_fbreg && ops->atom == DW_OP_fbreg && + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, ops->number, + /*is_pointer=*/false)) + 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) + /* pointer variables saved in a register 0 to 31 */ + if (ops->atom == (DW_OP_reg0 + data->reg) && + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, 0, + /*is_pointer=*/true)) + return DIE_FIND_CB_END; + + /* Local variables accessed by a register + offset */ + if (ops->atom == (DW_OP_breg0 + data->reg) && + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, ops->number, + /*is_pointer=*/false)) return DIE_FIND_CB_END; } else { + /* pointer variables saved in a register 32 or above */ if (ops->atom == DW_OP_regx && ops->number == data->reg && - nops == 1) + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, 0, + /*is_pointer=*/true)) + return DIE_FIND_CB_END; + + /* Local variables accessed by a register + offset */ + if (ops->atom == DW_OP_bregx && data->reg == ops->number && + check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->offset, ops->number2, + /*is_poitner=*/false)) return DIE_FIND_CB_END; } } @@ -1319,18 +1492,29 @@ 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 +1525,6 @@ 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; @@ -1356,27 +1538,10 @@ static int __die_find_var_addr_cb(Dwarf_Die *die_mem, void *arg) if (ops->atom != DW_OP_addr) continue; - if (data->addr < ops->number) - continue; - - if (data->addr == ops->number) { - /* Update offset relative to the start of the variable */ - data->offset = 0; + if (check_allowed_ops(ops, nops) && + match_var_offset(die_mem, data, data->addr, ops->number, + /*is_pointer=*/false)) 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; } @@ -1384,7 +1549,6 @@ static int __die_find_var_addr_cb(Dwarf_Die *die_mem, void *arg) /** * die_find_variable_by_addr - Find variable located at given address * @sc_die: a scope DIE - * @pc: the program address to find * @addr: the data address to find * @die_mem: a buffer to save the resulting DIE * @offset: the offset in the resulting type @@ -1392,12 +1556,10 @@ static int __die_find_var_addr_cb(Dwarf_Die *die_mem, void *arg) * Find the variable DIE located at the given address (in PC-relative mode). * This is usually for global variables. */ -Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr pc, - Dwarf_Addr addr, Dwarf_Die *die_mem, - int *offset) +Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr addr, + Dwarf_Die *die_mem, int *offset) { struct find_var_data data = { - .pc = pc, .addr = addr, }; Dwarf_Die *result; @@ -1407,7 +1569,164 @@ Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr pc, *offset = data.offset; return result; } -#endif + +static int __die_collect_vars_cb(Dwarf_Die *die_mem, void *arg) +{ + struct die_var_type **var_types = arg; + Dwarf_Die type_die; + int tag = dwarf_tag(die_mem); + Dwarf_Attribute attr; + Dwarf_Addr base, start, end; + Dwarf_Op *ops; + size_t nops; + struct die_var_type *vt; + + if (tag != DW_TAG_variable && tag != DW_TAG_formal_parameter) + return DIE_FIND_CB_SIBLING; + + if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL) + return DIE_FIND_CB_SIBLING; + + /* + * Only collect the first location as it can reconstruct the + * remaining state by following the instructions. + * start = 0 means it covers the whole range. + */ + if (dwarf_getlocations(&attr, 0, &base, &start, &end, &ops, &nops) <= 0) + return DIE_FIND_CB_SIBLING; + + if (!check_allowed_ops(ops, nops)) + return DIE_FIND_CB_SIBLING; + + if (die_get_real_type(die_mem, &type_die) == NULL) + return DIE_FIND_CB_SIBLING; + + vt = malloc(sizeof(*vt)); + if (vt == NULL) + return DIE_FIND_CB_END; + + vt->die_off = dwarf_dieoffset(&type_die); + vt->addr = start; + vt->reg = reg_from_dwarf_op(ops); + vt->offset = offset_from_dwarf_op(ops); + vt->next = *var_types; + *var_types = vt; + + return DIE_FIND_CB_SIBLING; +} + +/** + * die_collect_vars - Save all variables and parameters + * @sc_die: a scope DIE + * @var_types: a pointer to save the resulting list + * + * Save all variables and parameters in the @sc_die and save them to @var_types. + * The @var_types is a singly-linked list containing type and location info. + * Actual type can be retrieved using dwarf_offdie() with 'die_off' later. + * + * Callers should free @var_types. + */ +void die_collect_vars(Dwarf_Die *sc_die, struct die_var_type **var_types) +{ + Dwarf_Die die_mem; + + die_find_child(sc_die, __die_collect_vars_cb, (void *)var_types, &die_mem); +} + +static int __die_collect_global_vars_cb(Dwarf_Die *die_mem, void *arg) +{ + struct die_var_type **var_types = arg; + Dwarf_Die type_die; + int tag = dwarf_tag(die_mem); + Dwarf_Attribute attr; + Dwarf_Addr base, start, end; + Dwarf_Op *ops; + size_t nops; + struct die_var_type *vt; + + if (tag != DW_TAG_variable) + return DIE_FIND_CB_SIBLING; + + if (dwarf_attr(die_mem, DW_AT_location, &attr) == NULL) + return DIE_FIND_CB_SIBLING; + + /* Only collect the location with an absolute address. */ + if (dwarf_getlocations(&attr, 0, &base, &start, &end, &ops, &nops) <= 0) + return DIE_FIND_CB_SIBLING; + + if (ops->atom != DW_OP_addr) + return DIE_FIND_CB_SIBLING; + + if (!check_allowed_ops(ops, nops)) + return DIE_FIND_CB_SIBLING; + + if (die_get_real_type(die_mem, &type_die) == NULL) + return DIE_FIND_CB_SIBLING; + + vt = malloc(sizeof(*vt)); + if (vt == NULL) + return DIE_FIND_CB_END; + + vt->die_off = dwarf_dieoffset(&type_die); + vt->addr = ops->number; + vt->reg = -1; + vt->offset = 0; + vt->next = *var_types; + *var_types = vt; + + return DIE_FIND_CB_SIBLING; +} + +/** + * die_collect_global_vars - Save all global variables + * @cu_die: a CU DIE + * @var_types: a pointer to save the resulting list + * + * Save all global variables in the @cu_die and save them to @var_types. + * The @var_types is a singly-linked list containing type and location info. + * Actual type can be retrieved using dwarf_offdie() with 'die_off' later. + * + * Callers should free @var_types. + */ +void die_collect_global_vars(Dwarf_Die *cu_die, struct die_var_type **var_types) +{ + Dwarf_Die die_mem; + + die_find_child(cu_die, __die_collect_global_vars_cb, (void *)var_types, &die_mem); +} + +/** + * die_get_cfa - Get frame base information + * @dwarf: a Dwarf info + * @pc: program address + * @preg: pointer for saved register + * @poffset: pointer for saved offset + * + * This function gets register and offset for CFA (Canonical Frame Address) + * by searching the CIE/FDE info. The CFA usually points to the start address + * of the current stack frame and local variables can be located using an offset + * from the CFA. The @preg and @poffset will be updated if it returns 0. + */ +int die_get_cfa(Dwarf *dwarf, u64 pc, int *preg, int *poffset) +{ + Dwarf_CFI *cfi; + Dwarf_Frame *frame = NULL; + Dwarf_Op *ops = NULL; + size_t nops; + + cfi = dwarf_getcfi(dwarf); + if (cfi == NULL) + return -1; + + if (!dwarf_cfi_addrframe(cfi, pc, &frame) && + !dwarf_frame_cfa(frame, &ops, &nops) && + check_allowed_ops(ops, nops)) { + *preg = reg_from_dwarf_op(ops); + *poffset = offset_from_dwarf_op(ops); + return 0; + } + return -1; +} /* * die_has_loclist - Check if DW_AT_location of @vr_die is a location list @@ -1640,3 +1959,123 @@ int die_get_scopes(Dwarf_Die *cu_die, Dwarf_Addr pc, Dwarf_Die **scopes) *scopes = data.scopes; return data.nr; } + +static int __die_find_member_offset_cb(Dwarf_Die *die_mem, void *arg) +{ + Dwarf_Die type_die; + Dwarf_Word size, loc; + Dwarf_Word offset = (long)arg; + int tag = dwarf_tag(die_mem); + + if (tag != DW_TAG_member) + return DIE_FIND_CB_SIBLING; + + /* Unions might not have location */ + if (die_get_data_member_location(die_mem, &loc) < 0) { + Dwarf_Attribute attr; + + if (dwarf_attr_integrate(die_mem, DW_AT_data_bit_offset, &attr) && + dwarf_formudata(&attr, &loc) == 0) + loc /= 8; + else + loc = 0; + } + + if (offset == loc) + return DIE_FIND_CB_END; + + if (die_get_real_type(die_mem, &type_die) == NULL) { + // TODO: add a pr_debug_dtp() later for this unlikely failure + return DIE_FIND_CB_SIBLING; + } + + if (dwarf_aggregate_size(&type_die, &size) < 0) + size = 0; + + if (loc < offset && offset < (loc + size)) + return DIE_FIND_CB_END; + + return DIE_FIND_CB_SIBLING; +} + +/** + * die_get_member_type - Return type info of struct member + * @type_die: a type DIE + * @offset: offset in the type + * @die_mem: a buffer to save the resulting DIE + * + * This function returns a type of a member in @type_die where it's located at + * @offset if it's a struct. For now, it just returns the first matching + * member in a union. For other types, it'd return the given type directly + * if it's within the size of the type or NULL otherwise. + */ +Dwarf_Die *die_get_member_type(Dwarf_Die *type_die, int offset, + Dwarf_Die *die_mem) +{ + Dwarf_Die *member; + Dwarf_Die mb_type; + int tag; + + tag = dwarf_tag(type_die); + /* If it's not a compound type, return the type directly */ + if (tag != DW_TAG_structure_type && tag != DW_TAG_union_type) { + Dwarf_Word size; + + if (dwarf_aggregate_size(type_die, &size) < 0) + size = 0; + + if ((unsigned)offset >= size) + return NULL; + + *die_mem = *type_die; + return die_mem; + } + + mb_type = *type_die; + /* TODO: Handle union types better? */ + while (tag == DW_TAG_structure_type || tag == DW_TAG_union_type) { + member = die_find_child(&mb_type, __die_find_member_offset_cb, + (void *)(long)offset, die_mem); + if (member == NULL) + return NULL; + + if (die_get_real_type(member, &mb_type) == NULL) + return NULL; + + tag = dwarf_tag(&mb_type); + + if (tag == DW_TAG_structure_type || tag == DW_TAG_union_type) { + Dwarf_Word loc; + + /* Update offset for the start of the member struct */ + if (die_get_data_member_location(member, &loc) == 0) + offset -= loc; + } + } + *die_mem = mb_type; + return die_mem; +} + +/** + * die_deref_ptr_type - Return type info for pointer access + * @ptr_die: a pointer type DIE + * @offset: access offset for the pointer + * @die_mem: a buffer to save the resulting DIE + * + * This function follows the pointer in @ptr_die with given @offset + * and saves the resulting type in @die_mem. If the pointer points + * a struct type, actual member at the offset would be returned. + */ +Dwarf_Die *die_deref_ptr_type(Dwarf_Die *ptr_die, int offset, + Dwarf_Die *die_mem) +{ + Dwarf_Die type_die; + + if (dwarf_tag(ptr_die) != DW_TAG_pointer_type) + return NULL; + + if (die_get_real_type(ptr_die, &type_die) == NULL) + return NULL; + + return die_get_member_type(&type_die, offset, die_mem); +} |