On 5/4/22 14:32, Alexander Monakov wrote:
> On Wed, 4 May 2022, Martin Liška wrote:
>
>> The patch is a follow-up of the discussion we've got in:
>> https://gcc.gnu.org/pipermail/gcc-patches/2022-May/593901.html
>>
>> Mold linker would appreciate knowing in advance if get_symbols_v3 is
>> supported
>> by a GCC plug-in or not.
>>
>> Ready to be installed?
>
> Quick note: if the linker is supposed to check for presence of this symbol
> via dlsym(), I expect it won't work as-is since lto-plugin.map hides every
> symbol except 'onload'.
Oh, good point!
Changing that, I get now:
$ nm ./lto-plugin/.libs/liblto_plugin.so | grep v3
0000000000015008 D supports_get_symbols_v3
>
> (also it might be nicer to reword the comment to say 'Presence of the
> following
> symbols is used for ...', because you're leaving the value as 'false').
Sure. I'm also changing it's default value.
Sending v2.
Cheers,
Martin
>
> Alexander
>
>> Thanks,
>> Martin
>>
>> lto-plugin/ChangeLog:
>>
>> * lto-plugin.c (supports_get_symbols_v3): Add symbol.
>> ---
>> lto-plugin/lto-plugin.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>> diff --git a/lto-plugin/lto-plugin.c b/lto-plugin/lto-plugin.c
>> index 47378435612..049f3841d5b 100644
>> --- a/lto-plugin/lto-plugin.c
>> +++ b/lto-plugin/lto-plugin.c
>> @@ -1554,3 +1554,8 @@ onload (struct ld_plugin_tv *tv)
>>
>> return LDPS_OK;
>> }
>> +
>> +/* The following symbols are used for dynamic detection of plug-in features
>> + from linker side. */
>> +
>> +bool supports_get_symbols_v3;
From 7b5acd79a749e50bc825a49b283d4f9e82a5e1b5 Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Tue, 1 Mar 2022 12:27:45 +0100
Subject: [PATCH] lto-plugin: add support for feature detection
lto-plugin/ChangeLog:
* lto-plugin.c (supports_get_symbols_v3): Add symbol and
initialize it to true;
lto-plugin/ChangeLog:
* lto-plugin.map: Add supports_get_symbols_v3 symbol.
---
lto-plugin/lto-plugin.c | 5 +++++
lto-plugin/lto-plugin.map | 5 ++++-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/lto-plugin/lto-plugin.c b/lto-plugin/lto-plugin.c
index 47378435612..6aac5867066 100644
--- a/lto-plugin/lto-plugin.c
+++ b/lto-plugin/lto-plugin.c
@@ -1554,3 +1554,8 @@ onload (struct ld_plugin_tv *tv)
return LDPS_OK;
}
+
+/* Presence of the following symbols is used for dynamic detection of plug-in features
+ from linker side. */
+
+bool supports_get_symbols_v3 = true;
diff --git a/lto-plugin/lto-plugin.map b/lto-plugin/lto-plugin.map
index 3d60e71cc2d..42dc50a819c 100644
--- a/lto-plugin/lto-plugin.map
+++ b/lto-plugin/lto-plugin.map
@@ -1,3 +1,6 @@
{
- global: onload; local: *;
+ global: onload;
+ supports_get_symbols_v3;
+
+ local: *;
};
--
2.36.0
