* [PATCH] LTO: Handle __real_SYM reference in IR
@ 2022-04-29 17:59 H.J. Lu
2022-05-03 16:45 ` H.J. Lu
2022-05-04 4:12 ` Alan Modra
0 siblings, 2 replies; 4+ messages in thread
From: H.J. Lu @ 2022-04-29 17:59 UTC (permalink / raw)
To: binutils
When an IR symbol SYM is referenced in IR via __real_SYM, its resolution
should be LDPR_PREVAILING_DEF, not PREVAILING_DEF_IRONLY, since LTO
doesn't know that __real_SYM should be resolved by SYM.
bfd/
PR ld/29086
* elflink.c (_bfd_elf_merge_symbol): Mark SYM is referenced in
IR if __real_SYM is referenced in IR.
include/
PR ld/29086
* bfdlink.h (bfd_link_hash_entry): Add ir_ref_real.
ld/
PR ld/29086
* plugin.c (get_symbols): Resolve SYM definition to
LDPR_PREVAILING_DEF for __real_SYM reference in IR.
* testsuite/ld-plugin/lto.exp: Run PR ld/29086 test.
* testsuite/ld-plugin/pr29086.c: New file.
---
bfd/elflink.c | 15 +++++++++++++--
include/bfdlink.h | 4 ++++
ld/plugin.c | 7 +++++--
ld/testsuite/ld-plugin/lto.exp | 8 ++++++++
ld/testsuite/ld-plugin/pr29086.c | 19 +++++++++++++++++++
5 files changed, 49 insertions(+), 4 deletions(-)
create mode 100644 ld/testsuite/ld-plugin/pr29086.c
diff --git a/bfd/elflink.c b/bfd/elflink.c
index b54ee517c75..ced07e40524 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -1101,8 +1101,19 @@ _bfd_elf_merge_symbol (bfd *abfd,
if (! bfd_is_und_section (sec))
h = elf_link_hash_lookup (elf_hash_table (info), name, true, false, false);
else
- h = ((struct elf_link_hash_entry *)
- bfd_wrapped_link_hash_lookup (abfd, info, name, true, false, false));
+ {
+ h = ((struct elf_link_hash_entry *)
+ bfd_wrapped_link_hash_lookup (abfd, info, name, true, false,
+ false));
+ /* Mark SYM is referenced in IR if __real_SYM is referenced in
+ IR. */
+ if (h != NULL
+ && info->wrap_hash != NULL
+ && (abfd->flags & BFD_PLUGIN) != 0
+ && strcmp (h->root.root.string,
+ name + sizeof "__real_" - 1) == 0)
+ h->root.ir_ref_real = 1;
+ }
if (h == NULL)
return false;
*sym_hash = h;
diff --git a/include/bfdlink.h b/include/bfdlink.h
index b16f3f44ca5..3b8cc7f8f96 100644
--- a/include/bfdlink.h
+++ b/include/bfdlink.h
@@ -114,6 +114,10 @@ struct bfd_link_hash_entry
as distinct from a LTO IR object file. */
unsigned int non_ir_ref_dynamic : 1;
+ /* The symbol, SYM, is referenced by __real_SYM in an LTO IR object
+ file. */
+ unsigned int ir_ref_real : 1;
+
/* Symbol is a built-in define. These will be overridden by PROVIDE
in a linker script. */
unsigned int linker_def : 1;
diff --git a/ld/plugin.c b/ld/plugin.c
index 6db52d16802..c8cdf580a67 100644
--- a/ld/plugin.c
+++ b/ld/plugin.c
@@ -863,8 +863,11 @@ get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms,
/* We need to know if the sym is referenced from non-IR files. Or
even potentially-referenced, perhaps in a future final link if
this is a partial one, perhaps dynamically at load-time if the
- symbol is externally visible. Also check for wrapper symbol. */
- if (blhe->non_ir_ref_regular || wrap_status == wrapper)
+ symbol is externally visible. Also check for __real_SYM
+ reference and wrapper symbol. */
+ if (blhe->non_ir_ref_regular
+ || blhe->ir_ref_real
+ || wrap_status == wrapper)
res = LDPR_PREVAILING_DEF;
else if (wrap_status == wrapped)
res = LDPR_RESOLVED_IR;
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index 33af6c45a41..fa5d2500aa3 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -522,6 +522,14 @@ set lto_link_elf_tests [list \
{{"nm" {-D} "pr28849.d"}} \
"pr28849" \
] \
+ [list \
+ "PR ld/pr29086" \
+ "-Wl,--wrap=foo" \
+ "-O0 -flto" \
+ {pr29086.c} \
+ {} \
+ "pr29086" \
+ ] \
]
# PR 14918 checks that libgcc is not spuriously included in a shared link of
diff --git a/ld/testsuite/ld-plugin/pr29086.c b/ld/testsuite/ld-plugin/pr29086.c
new file mode 100644
index 00000000000..d333d68e262
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr29086.c
@@ -0,0 +1,19 @@
+int
+foo (void)
+{
+ return 0;
+}
+
+int
+main ()
+{
+ return foo ();
+}
+
+extern int __real_foo (void);
+
+int
+__wrap_foo (void)
+{
+ return __real_foo ();
+}
--
2.35.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] LTO: Handle __real_SYM reference in IR
2022-04-29 17:59 [PATCH] LTO: Handle __real_SYM reference in IR H.J. Lu
@ 2022-05-03 16:45 ` H.J. Lu
2022-05-04 4:12 ` Alan Modra
1 sibling, 0 replies; 4+ messages in thread
From: H.J. Lu @ 2022-05-03 16:45 UTC (permalink / raw)
To: binutils, Alan Modra, Nick Clifton
On Fri, Apr 29, 2022 at 10:59 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> When an IR symbol SYM is referenced in IR via __real_SYM, its resolution
> should be LDPR_PREVAILING_DEF, not PREVAILING_DEF_IRONLY, since LTO
> doesn't know that __real_SYM should be resolved by SYM.
>
> bfd/
>
> PR ld/29086
> * elflink.c (_bfd_elf_merge_symbol): Mark SYM is referenced in
> IR if __real_SYM is referenced in IR.
>
> include/
>
> PR ld/29086
> * bfdlink.h (bfd_link_hash_entry): Add ir_ref_real.
>
> ld/
>
> PR ld/29086
> * plugin.c (get_symbols): Resolve SYM definition to
> LDPR_PREVAILING_DEF for __real_SYM reference in IR.
> * testsuite/ld-plugin/lto.exp: Run PR ld/29086 test.
> * testsuite/ld-plugin/pr29086.c: New file.
> ---
> bfd/elflink.c | 15 +++++++++++++--
> include/bfdlink.h | 4 ++++
> ld/plugin.c | 7 +++++--
> ld/testsuite/ld-plugin/lto.exp | 8 ++++++++
> ld/testsuite/ld-plugin/pr29086.c | 19 +++++++++++++++++++
> 5 files changed, 49 insertions(+), 4 deletions(-)
> create mode 100644 ld/testsuite/ld-plugin/pr29086.c
>
> diff --git a/bfd/elflink.c b/bfd/elflink.c
> index b54ee517c75..ced07e40524 100644
> --- a/bfd/elflink.c
> +++ b/bfd/elflink.c
> @@ -1101,8 +1101,19 @@ _bfd_elf_merge_symbol (bfd *abfd,
> if (! bfd_is_und_section (sec))
> h = elf_link_hash_lookup (elf_hash_table (info), name, true, false, false);
> else
> - h = ((struct elf_link_hash_entry *)
> - bfd_wrapped_link_hash_lookup (abfd, info, name, true, false, false));
> + {
> + h = ((struct elf_link_hash_entry *)
> + bfd_wrapped_link_hash_lookup (abfd, info, name, true, false,
> + false));
> + /* Mark SYM is referenced in IR if __real_SYM is referenced in
> + IR. */
> + if (h != NULL
> + && info->wrap_hash != NULL
> + && (abfd->flags & BFD_PLUGIN) != 0
> + && strcmp (h->root.root.string,
> + name + sizeof "__real_" - 1) == 0)
> + h->root.ir_ref_real = 1;
> + }
> if (h == NULL)
> return false;
> *sym_hash = h;
> diff --git a/include/bfdlink.h b/include/bfdlink.h
> index b16f3f44ca5..3b8cc7f8f96 100644
> --- a/include/bfdlink.h
> +++ b/include/bfdlink.h
> @@ -114,6 +114,10 @@ struct bfd_link_hash_entry
> as distinct from a LTO IR object file. */
> unsigned int non_ir_ref_dynamic : 1;
>
> + /* The symbol, SYM, is referenced by __real_SYM in an LTO IR object
> + file. */
> + unsigned int ir_ref_real : 1;
> +
> /* Symbol is a built-in define. These will be overridden by PROVIDE
> in a linker script. */
> unsigned int linker_def : 1;
> diff --git a/ld/plugin.c b/ld/plugin.c
> index 6db52d16802..c8cdf580a67 100644
> --- a/ld/plugin.c
> +++ b/ld/plugin.c
> @@ -863,8 +863,11 @@ get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms,
> /* We need to know if the sym is referenced from non-IR files. Or
> even potentially-referenced, perhaps in a future final link if
> this is a partial one, perhaps dynamically at load-time if the
> - symbol is externally visible. Also check for wrapper symbol. */
> - if (blhe->non_ir_ref_regular || wrap_status == wrapper)
> + symbol is externally visible. Also check for __real_SYM
> + reference and wrapper symbol. */
> + if (blhe->non_ir_ref_regular
> + || blhe->ir_ref_real
> + || wrap_status == wrapper)
> res = LDPR_PREVAILING_DEF;
> else if (wrap_status == wrapped)
> res = LDPR_RESOLVED_IR;
> diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
> index 33af6c45a41..fa5d2500aa3 100644
> --- a/ld/testsuite/ld-plugin/lto.exp
> +++ b/ld/testsuite/ld-plugin/lto.exp
> @@ -522,6 +522,14 @@ set lto_link_elf_tests [list \
> {{"nm" {-D} "pr28849.d"}} \
> "pr28849" \
> ] \
> + [list \
> + "PR ld/pr29086" \
> + "-Wl,--wrap=foo" \
> + "-O0 -flto" \
> + {pr29086.c} \
> + {} \
> + "pr29086" \
> + ] \
> ]
>
> # PR 14918 checks that libgcc is not spuriously included in a shared link of
> diff --git a/ld/testsuite/ld-plugin/pr29086.c b/ld/testsuite/ld-plugin/pr29086.c
> new file mode 100644
> index 00000000000..d333d68e262
> --- /dev/null
> +++ b/ld/testsuite/ld-plugin/pr29086.c
> @@ -0,0 +1,19 @@
> +int
> +foo (void)
> +{
> + return 0;
> +}
> +
> +int
> +main ()
> +{
> + return foo ();
> +}
> +
> +extern int __real_foo (void);
> +
> +int
> +__wrap_foo (void)
> +{
> + return __real_foo ();
> +}
> --
> 2.35.1
>
Hi Nick, Alan,
Can you review this?
Thanks.
--
H.J.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] LTO: Handle __real_SYM reference in IR
2022-04-29 17:59 [PATCH] LTO: Handle __real_SYM reference in IR H.J. Lu
2022-05-03 16:45 ` H.J. Lu
@ 2022-05-04 4:12 ` Alan Modra
2022-05-04 23:26 ` H.J. Lu
1 sibling, 1 reply; 4+ messages in thread
From: Alan Modra @ 2022-05-04 4:12 UTC (permalink / raw)
To: H.J. Lu; +Cc: binutils
On Fri, Apr 29, 2022 at 10:59:32AM -0700, H.J. Lu via Binutils wrote:
> --- a/bfd/elflink.c
> +++ b/bfd/elflink.c
> @@ -1101,8 +1101,19 @@ _bfd_elf_merge_symbol (bfd *abfd,
> if (! bfd_is_und_section (sec))
> h = elf_link_hash_lookup (elf_hash_table (info), name, true, false, false);
> else
> - h = ((struct elf_link_hash_entry *)
> - bfd_wrapped_link_hash_lookup (abfd, info, name, true, false, false));
> + {
> + h = ((struct elf_link_hash_entry *)
> + bfd_wrapped_link_hash_lookup (abfd, info, name, true, false,
> + false));
> + /* Mark SYM is referenced in IR if __real_SYM is referenced in
> + IR. */
> + if (h != NULL
> + && info->wrap_hash != NULL
> + && (abfd->flags & BFD_PLUGIN) != 0
> + && strcmp (h->root.root.string,
> + name + sizeof "__real_" - 1) == 0)
> + h->root.ir_ref_real = 1;
> + }
> if (h == NULL)
> return false;
> *sym_hash = h;
How about putting the above in linker.c:bfd_wrapped_link_hash_lookup
instead, to avoid the extra strcmp? That seems like a better place to
me since there isn't really anything ELF specific about wrapped symbol
lookup.
Hmm, and maybe without the BFD_PLUGIN test and losing "ir" from the
flag name.
If that works for you, OK with those changes.
--
Alan Modra
Australia Development Lab, IBM
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] LTO: Handle __real_SYM reference in IR
2022-05-04 4:12 ` Alan Modra
@ 2022-05-04 23:26 ` H.J. Lu
0 siblings, 0 replies; 4+ messages in thread
From: H.J. Lu @ 2022-05-04 23:26 UTC (permalink / raw)
To: Alan Modra; +Cc: binutils
[-- Attachment #1: Type: text/plain, Size: 1544 bytes --]
On Tue, May 3, 2022 at 9:12 PM Alan Modra <amodra@gmail.com> wrote:
>
> On Fri, Apr 29, 2022 at 10:59:32AM -0700, H.J. Lu via Binutils wrote:
> > --- a/bfd/elflink.c
> > +++ b/bfd/elflink.c
> > @@ -1101,8 +1101,19 @@ _bfd_elf_merge_symbol (bfd *abfd,
> > if (! bfd_is_und_section (sec))
> > h = elf_link_hash_lookup (elf_hash_table (info), name, true, false, false);
> > else
> > - h = ((struct elf_link_hash_entry *)
> > - bfd_wrapped_link_hash_lookup (abfd, info, name, true, false, false));
> > + {
> > + h = ((struct elf_link_hash_entry *)
> > + bfd_wrapped_link_hash_lookup (abfd, info, name, true, false,
> > + false));
> > + /* Mark SYM is referenced in IR if __real_SYM is referenced in
> > + IR. */
> > + if (h != NULL
> > + && info->wrap_hash != NULL
> > + && (abfd->flags & BFD_PLUGIN) != 0
> > + && strcmp (h->root.root.string,
> > + name + sizeof "__real_" - 1) == 0)
> > + h->root.ir_ref_real = 1;
> > + }
> > if (h == NULL)
> > return false;
> > *sym_hash = h;
>
> How about putting the above in linker.c:bfd_wrapped_link_hash_lookup
> instead, to avoid the extra strcmp? That seems like a better place to
> me since there isn't really anything ELF specific about wrapped symbol
> lookup.
>
> Hmm, and maybe without the BFD_PLUGIN test and losing "ir" from the
> flag name.
>
> If that works for you, OK with those changes.
>
It works. This is what I am checking in.
Thanks.
--
H.J.
[-- Attachment #2: v2-0001-LTO-Handle-__real_SYM-reference-in-IR.patch --]
[-- Type: text/x-patch, Size: 3750 bytes --]
From 3463163b5b9901a15567b98837c55e05f33f6b9f Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Mon, 25 Apr 2022 10:51:39 -0700
Subject: [PATCH v2] LTO: Handle __real_SYM reference in IR
When an IR symbol SYM is referenced in IR via __real_SYM, its resolution
should be LDPR_PREVAILING_DEF, not PREVAILING_DEF_IRONLY, since LTO
doesn't know that __real_SYM should be resolved by SYM.
bfd/
PR ld/29086
* linker.c (bfd_wrapped_link_hash_lookup): Mark SYM is referenced
via __real_SYM.
include/
PR ld/29086
* bfdlink.h (bfd_link_hash_entry): Add ref_real.
ld/
PR ld/29086
* plugin.c (get_symbols): Resolve SYM definition to
LDPR_PREVAILING_DEF for __real_SYM reference.
* testsuite/ld-plugin/lto.exp: Run PR ld/29086 test.
* testsuite/ld-plugin/pr29086.c: New file.
---
bfd/linker.c | 1 +
include/bfdlink.h | 3 +++
ld/plugin.c | 7 +++++--
ld/testsuite/ld-plugin/lto.exp | 8 ++++++++
ld/testsuite/ld-plugin/pr29086.c | 19 +++++++++++++++++++
5 files changed, 36 insertions(+), 2 deletions(-)
create mode 100644 ld/testsuite/ld-plugin/pr29086.c
diff --git a/bfd/linker.c b/bfd/linker.c
index 088c1d06f3d..e9ebdbad040 100644
--- a/bfd/linker.c
+++ b/bfd/linker.c
@@ -599,6 +599,7 @@ bfd_wrapped_link_hash_lookup (bfd *abfd,
n[1] = '\0';
strcat (n, l + sizeof REAL - 1);
h = bfd_link_hash_lookup (info->hash, n, create, true, follow);
+ h->ref_real = 1;
free (n);
return h;
}
diff --git a/include/bfdlink.h b/include/bfdlink.h
index 88cc8e26183..27a8e11cc22 100644
--- a/include/bfdlink.h
+++ b/include/bfdlink.h
@@ -114,6 +114,9 @@ struct bfd_link_hash_entry
as distinct from a LTO IR object file. */
unsigned int non_ir_ref_dynamic : 1;
+ /* The symbol, SYM, is referenced by __real_SYM in an object file. */
+ unsigned int ref_real : 1;
+
/* Symbol is a built-in define. These will be overridden by PROVIDE
in a linker script. */
unsigned int linker_def : 1;
diff --git a/ld/plugin.c b/ld/plugin.c
index 6db52d16802..fe203104677 100644
--- a/ld/plugin.c
+++ b/ld/plugin.c
@@ -863,8 +863,11 @@ get_symbols (const void *handle, int nsyms, struct ld_plugin_symbol *syms,
/* We need to know if the sym is referenced from non-IR files. Or
even potentially-referenced, perhaps in a future final link if
this is a partial one, perhaps dynamically at load-time if the
- symbol is externally visible. Also check for wrapper symbol. */
- if (blhe->non_ir_ref_regular || wrap_status == wrapper)
+ symbol is externally visible. Also check for __real_SYM
+ reference and wrapper symbol. */
+ if (blhe->non_ir_ref_regular
+ || blhe->ref_real
+ || wrap_status == wrapper)
res = LDPR_PREVAILING_DEF;
else if (wrap_status == wrapped)
res = LDPR_RESOLVED_IR;
diff --git a/ld/testsuite/ld-plugin/lto.exp b/ld/testsuite/ld-plugin/lto.exp
index f4ea1d48533..4e8e2dc7748 100644
--- a/ld/testsuite/ld-plugin/lto.exp
+++ b/ld/testsuite/ld-plugin/lto.exp
@@ -522,6 +522,14 @@ set lto_link_elf_tests [list \
{{"nm" {-D} "pr28849.d"}} \
"pr28849" \
] \
+ [list \
+ "PR ld/pr29086" \
+ "-Wl,--wrap=foo" \
+ "-O0 -flto" \
+ {pr29086.c} \
+ {} \
+ "pr29086" \
+ ] \
]
# PR 14918 checks that libgcc is not spuriously included in a shared link of
diff --git a/ld/testsuite/ld-plugin/pr29086.c b/ld/testsuite/ld-plugin/pr29086.c
new file mode 100644
index 00000000000..d333d68e262
--- /dev/null
+++ b/ld/testsuite/ld-plugin/pr29086.c
@@ -0,0 +1,19 @@
+int
+foo (void)
+{
+ return 0;
+}
+
+int
+main ()
+{
+ return foo ();
+}
+
+extern int __real_foo (void);
+
+int
+__wrap_foo (void)
+{
+ return __real_foo ();
+}
--
2.35.1
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-05-04 23:27 UTC | newest]
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2022-04-29 17:59 [PATCH] LTO: Handle __real_SYM reference in IR H.J. Lu
2022-05-03 16:45 ` H.J. Lu
2022-05-04 4:12 ` Alan Modra
2022-05-04 23:26 ` H.J. Lu
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