@@ -226,7 +226,7 @@ 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 &&
@@ -265,6 +265,9 @@ 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)) {
@@ -296,7 +299,33 @@ 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) {
@@ -306,13 +335,13 @@ static int find_data_type_die(struct debuginfo *di, u64 pc, u64 addr,
} 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;
}
@@ -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;
}
@@ -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' */
@@ -164,6 +165,8 @@ 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;