Hello,
The attached patch adds PLT entry recognition for aarch64, plus a couple
of other small fixes.
Regards,
Jonathan Byrd
Senior Application Developer
Allinea Software Ltd.
diff --git a/src/aarch64/Gstep.c b/src/aarch64/Gstep.c
index 0c35f98..35e7d1a 100644
--- a/src/aarch64/Gstep.c
+++ b/src/aarch64/Gstep.c
@@ -27,6 +27,30 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include "unwind_i.h"
#include "offsets.h"
+/* Recognise PLT entries such as:
+ 40ddf0: b0000570 adrp x16, 4ba000 <_GLOBAL_OFFSET_TABLE_+0x2a8>
+ 40ddf4: f9433611 ldr x17, [x16,#1640]
+ 40ddf8: 9119a210 add x16, x16, #0x668
+ 40ddfc: d61f0220 br x17 */
+static int
+is_plt_entry (struct dwarf_cursor *c)
+{
+ unw_word_t w0, w1;
+ unw_accessors_t *a;
+ int ret;
+
+ a = unw_get_accessors (c->as);
+ if ((ret = (*a->access_mem) (c->as, c->ip, &w0, 0, c->as_arg)) < 0
+ || (ret = (*a->access_mem) (c->as, c->ip + 8, &w1, 0, c->as_arg)) < 0)
+ return 0;
+
+ ret = (((w0 & 0xff000000ff000000) == 0xf9000000b0000000)
+ && ((w1 & 0xffffffffff000000) == 0xd61f022091000000));
+
+ Debug (14, "ip=0x%lx => 0x%016lx 0x%016lx, ret = %d\n", c->ip, w0, w1, ret);
+ return ret;
+}
+
PROTECTED int
unw_handle_signal_frame (unw_cursor_t *cursor)
{
@@ -101,6 +125,7 @@ unw_handle_signal_frame (unw_cursor_t *cursor)
dwarf_get (&c->dwarf, c->dwarf.loc[UNW_AARCH64_PC], &c->dwarf.ip);
c->dwarf.pi_valid = 0;
+ c->dwarf.use_prev_instr = 0;
return 1;
}
@@ -125,7 +150,40 @@ unw_step (unw_cursor_t *cursor)
return ret;
if (unlikely (ret < 0))
- return 0;
+ {
+ /* DWARF failed. */
+ if (is_plt_entry (&c->dwarf))
+ {
+ Debug (2, "found plt entry\n");
+ c->frame_info.frame_type = UNW_AARCH64_FRAME_STANDARD;
+ }
+ else
+ {
+ Debug (2, "fallback\n");
+ c->frame_info.frame_type = UNW_AARCH64_FRAME_GUESSED;
+ }
+ /* Use link register (X30). */
+ c->frame_info.cfa_reg_offset = 0;
+ c->frame_info.cfa_reg_sp = 0;
+ c->frame_info.fp_cfa_offset = -1;
+ c->frame_info.lr_cfa_offset = -1;
+ c->frame_info.sp_cfa_offset = -1;
+ c->dwarf.loc[UNW_AARCH64_PC] = c->dwarf.loc[UNW_AARCH64_X30];
+ c->dwarf.loc[UNW_AARCH64_X30] = DWARF_NULL_LOC;
+ if (!DWARF_IS_NULL_LOC (c->dwarf.loc[UNW_AARCH64_PC]))
+ {
+ ret = dwarf_get (&c->dwarf, c->dwarf.loc[UNW_AARCH64_PC], &c->dwarf.ip);
+ if (ret < 0)
+ {
+ Debug (2, "failed to get pc from link register: %d\n", ret);
+ return ret;
+ }
+ Debug (2, "link register (x30) = 0x%016lx\n", c->dwarf.ip);
+ ret = 1;
+ }
+ else
+ c->dwarf.ip = 0;
+ }
return (c->dwarf.ip == 0) ? 0 : 1;
}
diff --git a/src/dwarf/Gfde.c b/src/dwarf/Gfde.c
index dc973fe..b1e55d3 100644
--- a/src/dwarf/Gfde.c
+++ b/src/dwarf/Gfde.c
@@ -32,7 +32,7 @@ is_cie_id (unw_word_t val, int is_debug_frame)
0xffffffffffffffff (for 64-bit ELF). However, .eh_frame
uses 0. */
if (is_debug_frame)
- return (val == - (uint32_t) 1 || val == - (uint64_t) 1);
+ return (val == (uint32_t)(-1) || val == (uint64_t)(-1));
else
return (val == 0);
}
diff --git a/src/dwarf/Gfind_proc_info-lsb.c b/src/dwarf/Gfind_proc_info-lsb.c
index 6e1f4c3..2a0e6d0 100644
--- a/src/dwarf/Gfind_proc_info-lsb.c
+++ b/src/dwarf/Gfind_proc_info-lsb.c
@@ -650,12 +650,13 @@ dwarf_callback (struct dl_phdr_info *info, size_t size, void *ptr)
/* XXX we know how to build a local binary search table for
.debug_frame, so we could do that here too. */
- cb_data->single_fde = 1;
found = linear_search (unw_local_addr_space, ip,
eh_frame_start, eh_frame_end, fde_count,
pi, need_unwind_info, NULL);
if (found != 1)
found = 0;
+ else
+ cb_data->single_fde = 1;
}
else
{
diff --git a/src/dwarf/Gparser.c b/src/dwarf/Gparser.c
index 3a47255..1e59642 100644
--- a/src/dwarf/Gparser.c
+++ b/src/dwarf/Gparser.c
@@ -792,7 +792,7 @@ apply_reg_state (struct dwarf_cursor *c, struct dwarf_reg_state *rs)
break;
case DWARF_WHERE_REG:
- c->loc[i] = DWARF_REG_LOC (c, dwarf_to_unw_regnum (rs->reg[i].val));
+ c->loc[i] = c->loc[rs->reg[i].val];
break;
case DWARF_WHERE_EXPR:
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