05853d0d4a
- Fix reference from compilation unit to partial unit [swo#25398]. * dwz-fix-reference-from-pu-to-cu.patch OBS-URL: https://build.opensuse.org/request/show/765148 OBS-URL: https://build.opensuse.org/package/show/devel:tools:compiler/dwz?expand=0&rev=26
99 lines
3.5 KiB
Diff
99 lines
3.5 KiB
Diff
Fix reference from PU to CU
|
|
|
|
[ Backport of master commit bce3238. ]
|
|
|
|
Consider the following situation:
|
|
- we have two duplicate chains: {A, B} and {C, D, E}
|
|
- each duplicate chain has a representant: A' and C'
|
|
- there's a pseudo-ref from Z to D, which is using one of the CU-local dwarf
|
|
operators DW_OP_GNU_{{regval,deref,const}_type,convert,reinterpret} (which
|
|
is summarized in the code by setting D->die_op_type_referenced).
|
|
|
|
Schematically this looks like this:
|
|
...
|
|
(A') --------d-------> (A) --d--> (B)
|
|
| |
|
|
r r
|
|
| |
|
|
v v
|
|
(C') --d--> (C) --d--> (D) --d--> (E)
|
|
^
|
|
|
|
|
pr
|
|
|
|
|
(Z)
|
|
...
|
|
|
|
Because the die D is referenced using a CU-local dwarf operator, the die is
|
|
kept in the CU (even though it's part of a duplicate chain), to keep the
|
|
pseudo-ref valid. Also other CU-local refs to D keep pointing to D.
|
|
|
|
A situation however arises while writing out A' to a partial unit using A as
|
|
template, when we try to write out the reference to D, and arrive here in
|
|
in write_die with die == A', ref == A, refd == D and refdt == D:
|
|
...
|
|
if (refdt->die_dup && refdt->die_op_type_referenced)
|
|
{
|
|
if (cu == die_cu (refdt->die_dup))
|
|
refd = die_find_dup (refdt, refdt->die_dup, refd);
|
|
}
|
|
else if (refdt->die_dup)
|
|
refd = die_find_dup (refdt, refdt->die_dup, refd);
|
|
...
|
|
|
|
The first if condition evaluates to true because D->die_dup == C' and
|
|
D->die_op_type_referenced == 1.
|
|
|
|
But the following (nested) if condition evalutes to false, because A' and C'
|
|
are not part of the same unit.
|
|
|
|
Consequently, refd remains D, and we get a reference from a die in a partial
|
|
unit (A') to a die in a compilation unit (D):
|
|
...
|
|
(A') --------d--------> (A) --d--> (B)
|
|
\ | |
|
|
+---------------+ r r
|
|
\ | |
|
|
v v v
|
|
(C') --d--> (C) --d--> (D) ---d--> (E)
|
|
^
|
|
|
|
|
pr
|
|
|
|
|
(Z)
|
|
...
|
|
|
|
The behaviour that is triggered is one that is valid for writing out A, but is
|
|
incorrect because in fact we're writing out A' using A as template. Note that
|
|
this problem would not have occurred if the pseudo-reference pointed to E
|
|
instead, in which case we would have had the expected reference from A' to C'.
|
|
|
|
Fix this by detecting that we're writing out A' (in other words,
|
|
cu->cu_kind == CU_PU), and skipping the die_op_type_referenced
|
|
handling in that case, resulting in a reference from A' to C'.
|
|
|
|
2020-01-16 Tom de Vries <tdevries@suse.de>
|
|
|
|
PR dwz/25398
|
|
* dwz.c (write_die): Skip die_op_type_referenced handling if
|
|
cu->cu_kind == CU_PU.
|
|
|
|
---
|
|
dwz.c | 3 ++-
|
|
1 file changed, 2 insertions(+), 1 deletion(-)
|
|
|
|
diff --git a/dwz.c b/dwz.c
|
|
index c7db337..298bca1 100644
|
|
--- a/dwz.c
|
|
+++ b/dwz.c
|
|
@@ -9301,7 +9301,8 @@ write_die (unsigned char *ptr, dw_cu_ref cu, dw_die_ref die,
|
|
refdt = refd;
|
|
while (refdt->die_toplevel == 0)
|
|
refdt = refdt->die_parent;
|
|
- if (refdt->die_dup && refdt->die_op_type_referenced)
|
|
+ if (refdt->die_dup && refdt->die_op_type_referenced
|
|
+ && cu->cu_kind != CU_PU)
|
|
{
|
|
if (cu == die_cu (refdt->die_dup))
|
|
refd = die_find_dup (refdt, refdt->die_dup, refd);
|